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freebsd-skq/contrib/libpcap/gencode.c
hselasky 30f165e2d7 MFV r333789: libpcap 1.9.0 (pre-release) 
MFC after:	1 month
Sponsored by:	Mellanox Technologies
2018-05-28 08:12:18 +00:00

9243 lines
239 KiB
C
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/*#define CHASE_CHAIN*/
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <pcap-types.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#ifdef __NetBSD__
#include <sys/param.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>
#endif /* _WIN32 */
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <setjmp.h>
#include <stdarg.h>
#ifdef MSDOS
#include "pcap-dos.h"
#endif
#include "pcap-int.h"
#include "ethertype.h"
#include "nlpid.h"
#include "llc.h"
#include "gencode.h"
#include "ieee80211.h"
#include "atmuni31.h"
#include "sunatmpos.h"
#include "ppp.h"
#include "pcap/sll.h"
#include "pcap/ipnet.h"
#include "arcnet.h"
#include "grammar.h"
#include "scanner.h"
#if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
#include <linux/types.h>
#include <linux/if_packet.h>
#include <linux/filter.h>
#endif
#ifdef HAVE_NET_PFVAR_H
#include <sys/socket.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <net/if_pflog.h>
#endif
#ifndef offsetof
#define offsetof(s, e) ((size_t)&((s *)0)->e)
#endif
#ifdef _WIN32
#ifdef INET6
#if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
/* IPv6 address */
struct in6_addr
{
union
{
uint8_t u6_addr8[16];
uint16_t u6_addr16[8];
uint32_t u6_addr32[4];
} in6_u;
#define s6_addr in6_u.u6_addr8
#define s6_addr16 in6_u.u6_addr16
#define s6_addr32 in6_u.u6_addr32
#define s6_addr64 in6_u.u6_addr64
};
typedef unsigned short sa_family_t;
#define __SOCKADDR_COMMON(sa_prefix) \
sa_family_t sa_prefix##family
/* Ditto, for IPv6. */
struct sockaddr_in6
{
__SOCKADDR_COMMON (sin6_);
uint16_t sin6_port; /* Transport layer port # */
uint32_t sin6_flowinfo; /* IPv6 flow information */
struct in6_addr sin6_addr; /* IPv6 address */
};
#ifndef EAI_ADDRFAMILY
struct addrinfo {
int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
int ai_family; /* PF_xxx */
int ai_socktype; /* SOCK_xxx */
int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
size_t ai_addrlen; /* length of ai_addr */
char *ai_canonname; /* canonical name for hostname */
struct sockaddr *ai_addr; /* binary address */
struct addrinfo *ai_next; /* next structure in linked list */
};
#endif /* EAI_ADDRFAMILY */
#endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
#endif /* INET6 */
#else /* _WIN32 */
#include <netdb.h> /* for "struct addrinfo" */
#endif /* _WIN32 */
#include <pcap/namedb.h>
#include "nametoaddr.h"
#define ETHERMTU 1500
#ifndef ETHERTYPE_TEB
#define ETHERTYPE_TEB 0x6558
#endif
#ifndef IPPROTO_HOPOPTS
#define IPPROTO_HOPOPTS 0
#endif
#ifndef IPPROTO_ROUTING
#define IPPROTO_ROUTING 43
#endif
#ifndef IPPROTO_FRAGMENT
#define IPPROTO_FRAGMENT 44
#endif
#ifndef IPPROTO_DSTOPTS
#define IPPROTO_DSTOPTS 60
#endif
#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif
#define GENEVE_PORT 6081
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#define JMP(c) ((c)|BPF_JMP|BPF_K)
/*
* "Push" the current value of the link-layer header type and link-layer
* header offset onto a "stack", and set a new value. (It's not a
* full-blown stack; we keep only the top two items.)
*/
#define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
{ \
(cs)->prevlinktype = (cs)->linktype; \
(cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
(cs)->linktype = (new_linktype); \
(cs)->off_linkhdr.is_variable = (new_is_variable); \
(cs)->off_linkhdr.constant_part = (new_constant_part); \
(cs)->off_linkhdr.reg = (new_reg); \
(cs)->is_geneve = 0; \
}
/*
* Offset "not set" value.
*/
#define OFFSET_NOT_SET 0xffffffffU
/*
* Absolute offsets, which are offsets from the beginning of the raw
* packet data, are, in the general case, the sum of a variable value
* and a constant value; the variable value may be absent, in which
* case the offset is only the constant value, and the constant value
* may be zero, in which case the offset is only the variable value.
*
* bpf_abs_offset is a structure containing all that information:
*
* is_variable is 1 if there's a variable part.
*
* constant_part is the constant part of the value, possibly zero;
*
* if is_variable is 1, reg is the register number for a register
* containing the variable value if the register has been assigned,
* and -1 otherwise.
*/
typedef struct {
int is_variable;
u_int constant_part;
int reg;
} bpf_abs_offset;
/*
* Value passed to gen_load_a() to indicate what the offset argument
* is relative to the beginning of.
*/
enum e_offrel {
OR_PACKET, /* full packet data */
OR_LINKHDR, /* link-layer header */
OR_PREVLINKHDR, /* previous link-layer header */
OR_LLC, /* 802.2 LLC header */
OR_PREVMPLSHDR, /* previous MPLS header */
OR_LINKTYPE, /* link-layer type */
OR_LINKPL, /* link-layer payload */
OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */
OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */
OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */
};
/*
* We divy out chunks of memory rather than call malloc each time so
* we don't have to worry about leaking memory. It's probably
* not a big deal if all this memory was wasted but if this ever
* goes into a library that would probably not be a good idea.
*
* XXX - this *is* in a library....
*/
#define NCHUNKS 16
#define CHUNK0SIZE 1024
struct chunk {
size_t n_left;
void *m;
};
/* Code generator state */
struct _compiler_state {
jmp_buf top_ctx;
pcap_t *bpf_pcap;
struct icode ic;
int snaplen;
int linktype;
int prevlinktype;
int outermostlinktype;
bpf_u_int32 netmask;
int no_optimize;
/* Hack for handling VLAN and MPLS stacks. */
u_int label_stack_depth;
u_int vlan_stack_depth;
/* XXX */
u_int pcap_fddipad;
/*
* As errors are handled by a longjmp, anything allocated must
* be freed in the longjmp handler, so it must be reachable
* from that handler.
*
* One thing that's allocated is the result of pcap_nametoaddrinfo();
* it must be freed with freeaddrinfo(). This variable points to
* any addrinfo structure that would need to be freed.
*/
struct addrinfo *ai;
/*
* Various code constructs need to know the layout of the packet.
* These values give the necessary offsets from the beginning
* of the packet data.
*/
/*
* Absolute offset of the beginning of the link-layer header.
*/
bpf_abs_offset off_linkhdr;
/*
* If we're checking a link-layer header for a packet encapsulated
* in another protocol layer, this is the equivalent information
* for the previous layers' link-layer header from the beginning
* of the raw packet data.
*/
bpf_abs_offset off_prevlinkhdr;
/*
* This is the equivalent information for the outermost layers'
* link-layer header.
*/
bpf_abs_offset off_outermostlinkhdr;
/*
* Absolute offset of the beginning of the link-layer payload.
*/
bpf_abs_offset off_linkpl;
/*
* "off_linktype" is the offset to information in the link-layer
* header giving the packet type. This is an absolute offset
* from the beginning of the packet.
*
* For Ethernet, it's the offset of the Ethernet type field; this
* means that it must have a value that skips VLAN tags.
*
* For link-layer types that always use 802.2 headers, it's the
* offset of the LLC header; this means that it must have a value
* that skips VLAN tags.
*
* For PPP, it's the offset of the PPP type field.
*
* For Cisco HDLC, it's the offset of the CHDLC type field.
*
* For BSD loopback, it's the offset of the AF_ value.
*
* For Linux cooked sockets, it's the offset of the type field.
*
* off_linktype.constant_part is set to OFFSET_NOT_SET for no
* encapsulation, in which case, IP is assumed.
*/
bpf_abs_offset off_linktype;
/*
* TRUE if the link layer includes an ATM pseudo-header.
*/
int is_atm;
/*
* TRUE if "geneve" appeared in the filter; it causes us to
* generate code that checks for a Geneve header and assume
* that later filters apply to the encapsulated payload.
*/
int is_geneve;
/*
* TRUE if we need variable length part of VLAN offset
*/
int is_vlan_vloffset;
/*
* These are offsets for the ATM pseudo-header.
*/
u_int off_vpi;
u_int off_vci;
u_int off_proto;
/*
* These are offsets for the MTP2 fields.
*/
u_int off_li;
u_int off_li_hsl;
/*
* These are offsets for the MTP3 fields.
*/
u_int off_sio;
u_int off_opc;
u_int off_dpc;
u_int off_sls;
/*
* This is the offset of the first byte after the ATM pseudo_header,
* or -1 if there is no ATM pseudo-header.
*/
u_int off_payload;
/*
* These are offsets to the beginning of the network-layer header.
* They are relative to the beginning of the link-layer payload
* (i.e., they don't include off_linkhdr.constant_part or
* off_linkpl.constant_part).
*
* If the link layer never uses 802.2 LLC:
*
* "off_nl" and "off_nl_nosnap" are the same.
*
* If the link layer always uses 802.2 LLC:
*
* "off_nl" is the offset if there's a SNAP header following
* the 802.2 header;
*
* "off_nl_nosnap" is the offset if there's no SNAP header.
*
* If the link layer is Ethernet:
*
* "off_nl" is the offset if the packet is an Ethernet II packet
* (we assume no 802.3+802.2+SNAP);
*
* "off_nl_nosnap" is the offset if the packet is an 802.3 packet
* with an 802.2 header following it.
*/
u_int off_nl;
u_int off_nl_nosnap;
/*
* Here we handle simple allocation of the scratch registers.
* If too many registers are alloc'd, the allocator punts.
*/
int regused[BPF_MEMWORDS];
int curreg;
/*
* Memory chunks.
*/
struct chunk chunks[NCHUNKS];
int cur_chunk;
};
void PCAP_NORETURN
bpf_syntax_error(compiler_state_t *cstate, const char *msg)
{
bpf_error(cstate, "syntax error in filter expression: %s", msg);
/* NOTREACHED */
}
/* VARARGS */
void PCAP_NORETURN
bpf_error(compiler_state_t *cstate, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (cstate->bpf_pcap != NULL)
(void)pcap_vsnprintf(pcap_geterr(cstate->bpf_pcap),
PCAP_ERRBUF_SIZE, fmt, ap);
va_end(ap);
longjmp(cstate->top_ctx, 1);
/* NOTREACHED */
}
static void init_linktype(compiler_state_t *, pcap_t *);
static void init_regs(compiler_state_t *);
static int alloc_reg(compiler_state_t *);
static void free_reg(compiler_state_t *, int);
static void initchunks(compiler_state_t *cstate);
static void *newchunk(compiler_state_t *cstate, size_t);
static void freechunks(compiler_state_t *cstate);
static inline struct block *new_block(compiler_state_t *cstate, int);
static inline struct slist *new_stmt(compiler_state_t *cstate, int);
static struct block *gen_retblk(compiler_state_t *cstate, int);
static inline void syntax(compiler_state_t *cstate);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32);
static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32);
static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32);
static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32);
static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32);
static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_int32, bpf_u_int32);
static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
u_int, const u_char *);
static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, bpf_u_int32,
bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32);
static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
u_int, u_int);
static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
u_int);
static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
static struct block *gen_uncond(compiler_state_t *, int);
static inline struct block *gen_true(compiler_state_t *);
static inline struct block *gen_false(compiler_state_t *);
static struct block *gen_ether_linktype(compiler_state_t *, int);
static struct block *gen_ipnet_linktype(compiler_state_t *, int);
static struct block *gen_linux_sll_linktype(compiler_state_t *, int);
static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
static void insert_compute_vloffsets(compiler_state_t *, struct block *);
static struct slist *gen_abs_offset_varpart(compiler_state_t *,
bpf_abs_offset *);
static int ethertype_to_ppptype(int);
static struct block *gen_linktype(compiler_state_t *, int);
static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
static struct block *gen_llc_linktype(compiler_state_t *, int);
static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
int, int, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
struct in6_addr *, int, int, u_int, u_int);
#endif
static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
static struct block *gen_mpls_linktype(compiler_state_t *, int);
static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
int, int, int);
#ifdef INET6
static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
struct in6_addr *, int, int, int);
#endif
#ifndef INET6
static struct block *gen_gateway(compiler_state_t *, const u_char *,
struct addrinfo *, int, int);
#endif
static struct block *gen_ipfrag(compiler_state_t *);
static struct block *gen_portatom(compiler_state_t *, int, bpf_int32);
static struct block *gen_portrangeatom(compiler_state_t *, int, bpf_int32,
bpf_int32);
static struct block *gen_portatom6(compiler_state_t *, int, bpf_int32);
static struct block *gen_portrangeatom6(compiler_state_t *, int, bpf_int32,
bpf_int32);
struct block *gen_portop(compiler_state_t *, int, int, int);
static struct block *gen_port(compiler_state_t *, int, int, int);
struct block *gen_portrangeop(compiler_state_t *, int, int, int, int);
static struct block *gen_portrange(compiler_state_t *, int, int, int, int);
struct block *gen_portop6(compiler_state_t *, int, int, int);
static struct block *gen_port6(compiler_state_t *, int, int, int);
struct block *gen_portrangeop6(compiler_state_t *, int, int, int, int);
static struct block *gen_portrange6(compiler_state_t *, int, int, int, int);
static int lookup_proto(compiler_state_t *, const char *, int);
static struct block *gen_protochain(compiler_state_t *, int, int, int);
static struct block *gen_proto(compiler_state_t *, int, int, int);
static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
static struct block *gen_mac_multicast(compiler_state_t *, int);
static struct block *gen_len(compiler_state_t *, int, int);
static struct block *gen_check_802_11_data_frame(compiler_state_t *);
static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
static struct block *gen_ppi_dlt_check(compiler_state_t *);
static struct block *gen_msg_abbrev(compiler_state_t *, int type);
static void
initchunks(compiler_state_t *cstate)
{
int i;
for (i = 0; i < NCHUNKS; i++) {
cstate->chunks[i].n_left = 0;
cstate->chunks[i].m = NULL;
}
cstate->cur_chunk = 0;
}
static void *
newchunk(compiler_state_t *cstate, size_t n)
{
struct chunk *cp;
int k;
size_t size;
#ifndef __NetBSD__
/* XXX Round up to nearest long. */
n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
#else
/* XXX Round up to structure boundary. */
n = ALIGN(n);
#endif
cp = &cstate->chunks[cstate->cur_chunk];
if (n > cp->n_left) {
++cp;
k = ++cstate->cur_chunk;
if (k >= NCHUNKS)
bpf_error(cstate, "out of memory");
size = CHUNK0SIZE << k;
cp->m = (void *)malloc(size);
if (cp->m == NULL)
bpf_error(cstate, "out of memory");
memset((char *)cp->m, 0, size);
cp->n_left = size;
if (n > size)
bpf_error(cstate, "out of memory");
}
cp->n_left -= n;
return (void *)((char *)cp->m + cp->n_left);
}
static void
freechunks(compiler_state_t *cstate)
{
int i;
for (i = 0; i < NCHUNKS; ++i)
if (cstate->chunks[i].m != NULL)
free(cstate->chunks[i].m);
}
/*
* A strdup whose allocations are freed after code generation is over.
*/
char *
sdup(compiler_state_t *cstate, const char *s)
{
size_t n = strlen(s) + 1;
char *cp = newchunk(cstate, n);
strlcpy(cp, s, n);
return (cp);
}
static inline struct block *
new_block(compiler_state_t *cstate, int code)
{
struct block *p;
p = (struct block *)newchunk(cstate, sizeof(*p));
p->s.code = code;
p->head = p;
return p;
}
static inline struct slist *
new_stmt(compiler_state_t *cstate, int code)
{
struct slist *p;
p = (struct slist *)newchunk(cstate, sizeof(*p));
p->s.code = code;
return p;
}
static struct block *
gen_retblk(compiler_state_t *cstate, int v)
{
struct block *b = new_block(cstate, BPF_RET|BPF_K);
b->s.k = v;
return b;
}
static inline PCAP_NORETURN_DEF void
syntax(compiler_state_t *cstate)
{
bpf_error(cstate, "syntax error in filter expression");
}
int
pcap_compile(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
#ifdef _WIN32
static int done = 0;
#endif
compiler_state_t cstate;
const char * volatile xbuf = buf;
yyscan_t scanner = NULL;
YY_BUFFER_STATE in_buffer = NULL;
u_int len;
int rc;
/*
* If this pcap_t hasn't been activated, it doesn't have a
* link-layer type, so we can't use it.
*/
if (!p->activated) {
pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"not-yet-activated pcap_t passed to pcap_compile");
return (-1);
}
#ifdef _WIN32
if (!done)
pcap_wsockinit();
done = 1;
#endif
#ifdef ENABLE_REMOTE
/*
* If the device on which we're capturing need to be notified
* that a new filter is being compiled, do so.
*
* This allows them to save a copy of it, in case, for example,
* they're implementing a form of remote packet capture, and
* want the remote machine to filter out the packets in which
* it's sending the packets it's captured.
*
* XXX - the fact that we happen to be compiling a filter
* doesn't necessarily mean we'll be installing it as the
* filter for this pcap_t; we might be running it from userland
* on captured packets to do packet classification. We really
* need a better way of handling this, but this is all that
* the WinPcap code did.
*/
if (p->save_current_filter_op != NULL)
(p->save_current_filter_op)(p, buf);
#endif
initchunks(&cstate);
cstate.no_optimize = 0;
#ifdef INET6
cstate.ai = NULL;
#endif
cstate.ic.root = NULL;
cstate.ic.cur_mark = 0;
cstate.bpf_pcap = p;
init_regs(&cstate);
if (setjmp(cstate.top_ctx)) {
#ifdef INET6
if (cstate.ai != NULL)
freeaddrinfo(cstate.ai);
#endif
rc = -1;
goto quit;
}
cstate.netmask = mask;
cstate.snaplen = pcap_snapshot(p);
if (cstate.snaplen == 0) {
pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"snaplen of 0 rejects all packets");
rc = -1;
goto quit;
}
if (pcap_lex_init(&scanner) != 0)
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "can't initialize scanner");
in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
/*
* Associate the compiler state with the lexical analyzer
* state.
*/
pcap_set_extra(&cstate, scanner);
init_linktype(&cstate, p);
(void)pcap_parse(scanner, &cstate);
if (cstate.ic.root == NULL)
cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
if (optimize && !cstate.no_optimize) {
bpf_optimize(&cstate, &cstate.ic);
if (cstate.ic.root == NULL ||
(cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0))
bpf_error(&cstate, "expression rejects all packets");
}
program->bf_insns = icode_to_fcode(&cstate, &cstate.ic, cstate.ic.root, &len);
program->bf_len = len;
rc = 0; /* We're all okay */
quit:
/*
* Clean up everything for the lexical analyzer.
*/
if (in_buffer != NULL)
pcap__delete_buffer(in_buffer, scanner);
if (scanner != NULL)
pcap_lex_destroy(scanner);
/*
* Clean up our own allocated memory.
*/
freechunks(&cstate);
return (rc);
}
/*
* entry point for using the compiler with no pcap open
* pass in all the stuff that is needed explicitly instead.
*/
int
pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
pcap_t *p;
int ret;
p = pcap_open_dead(linktype_arg, snaplen_arg);
if (p == NULL)
return (-1);
ret = pcap_compile(p, program, buf, optimize, mask);
pcap_close(p);
return (ret);
}
/*
* Clean up a "struct bpf_program" by freeing all the memory allocated
* in it.
*/
void
pcap_freecode(struct bpf_program *program)
{
program->bf_len = 0;
if (program->bf_insns != NULL) {
free((char *)program->bf_insns);
program->bf_insns = NULL;
}
}
/*
* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
* which of the jt and jf fields has been resolved and which is a pointer
* back to another unresolved block (or nil). At least one of the fields
* in each block is already resolved.
*/
static void
backpatch(struct block *list, struct block *target)
{
struct block *next;
while (list) {
if (!list->sense) {
next = JT(list);
JT(list) = target;
} else {
next = JF(list);
JF(list) = target;
}
list = next;
}
}
/*
* Merge the lists in b0 and b1, using the 'sense' field to indicate
* which of jt and jf is the link.
*/
static void
merge(struct block *b0, struct block *b1)
{
register struct block **p = &b0;
/* Find end of list. */
while (*p)
p = !((*p)->sense) ? &JT(*p) : &JF(*p);
/* Concatenate the lists. */
*p = b1;
}
void
finish_parse(compiler_state_t *cstate, struct block *p)
{
struct block *ppi_dlt_check;
/*
* Insert before the statements of the first (root) block any
* statements needed to load the lengths of any variable-length
* headers into registers.
*
* XXX - a fancier strategy would be to insert those before the
* statements of all blocks that use those lengths and that
* have no predecessors that use them, so that we only compute
* the lengths if we need them. There might be even better
* approaches than that.
*
* However, those strategies would be more complicated, and
* as we don't generate code to compute a length if the
* program has no tests that use the length, and as most
* tests will probably use those lengths, we would just
* postpone computing the lengths so that it's not done
* for tests that fail early, and it's not clear that's
* worth the effort.
*/
insert_compute_vloffsets(cstate, p->head);
/*
* For DLT_PPI captures, generate a check of the per-packet
* DLT value to make sure it's DLT_IEEE802_11.
*
* XXX - TurboCap cards use DLT_PPI for Ethernet.
* Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
* with appropriate Ethernet information and use that rather
* than using something such as DLT_PPI where you don't know
* the link-layer header type until runtime, which, in the
* general case, would force us to generate both Ethernet *and*
* 802.11 code (*and* anything else for which PPI is used)
* and choose between them early in the BPF program?
*/
ppi_dlt_check = gen_ppi_dlt_check(cstate);
if (ppi_dlt_check != NULL)
gen_and(ppi_dlt_check, p);
backpatch(p, gen_retblk(cstate, cstate->snaplen));
p->sense = !p->sense;
backpatch(p, gen_retblk(cstate, 0));
cstate->ic.root = p->head;
}
void
gen_and(struct block *b0, struct block *b1)
{
backpatch(b0, b1->head);
b0->sense = !b0->sense;
b1->sense = !b1->sense;
merge(b1, b0);
b1->sense = !b1->sense;
b1->head = b0->head;
}
void
gen_or(struct block *b0, struct block *b1)
{
b0->sense = !b0->sense;
backpatch(b0, b1->head);
b0->sense = !b0->sense;
merge(b1, b0);
b1->head = b0->head;
}
void
gen_not(struct block *b)
{
b->sense = !b->sense;
}
static struct block *
gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v)
{
return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
}
static struct block *
gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v)
{
return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
}
static struct block *
gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v)
{
return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
}
static struct block *
gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v)
{
return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
}
static struct block *
gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v)
{
return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
}
static struct block *
gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, bpf_int32 v, bpf_u_int32 mask)
{
return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
}
static struct block *
gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size, const u_char *v)
{
register struct block *b, *tmp;
b = NULL;
while (size >= 4) {
register const u_char *p = &v[size - 4];
bpf_int32 w = ((bpf_int32)p[0] << 24) |
((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 4;
}
while (size >= 2) {
register const u_char *p = &v[size - 2];
bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 2;
}
if (size > 0) {
tmp = gen_cmp(cstate, offrel, offset, BPF_B, (bpf_int32)v[0]);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
}
return b;
}
/*
* AND the field of size "size" at offset "offset" relative to the header
* specified by "offrel" with "mask", and compare it with the value "v"
* with the test specified by "jtype"; if "reverse" is true, the test
* should test the opposite of "jtype".
*/
static struct block *
gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, bpf_u_int32 offset,
bpf_u_int32 size, bpf_u_int32 mask, bpf_u_int32 jtype, int reverse,
bpf_int32 v)
{
struct slist *s, *s2;
struct block *b;
s = gen_load_a(cstate, offrel, offset, size);
if (mask != 0xffffffff) {
s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
s2->s.k = mask;
sappend(s, s2);
}
b = new_block(cstate, JMP(jtype));
b->stmts = s;
b->s.k = v;
if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
gen_not(b);
return b;
}
static void
init_linktype(compiler_state_t *cstate, pcap_t *p)
{
cstate->pcap_fddipad = p->fddipad;
/*
* We start out with only one link-layer header.
*/
cstate->outermostlinktype = pcap_datalink(p);
cstate->off_outermostlinkhdr.constant_part = 0;
cstate->off_outermostlinkhdr.is_variable = 0;
cstate->off_outermostlinkhdr.reg = -1;
cstate->prevlinktype = cstate->outermostlinktype;
cstate->off_prevlinkhdr.constant_part = 0;
cstate->off_prevlinkhdr.is_variable = 0;
cstate->off_prevlinkhdr.reg = -1;
cstate->linktype = cstate->outermostlinktype;
cstate->off_linkhdr.constant_part = 0;
cstate->off_linkhdr.is_variable = 0;
cstate->off_linkhdr.reg = -1;
/*
* XXX
*/
cstate->off_linkpl.constant_part = 0;
cstate->off_linkpl.is_variable = 0;
cstate->off_linkpl.reg = -1;
cstate->off_linktype.constant_part = 0;
cstate->off_linktype.is_variable = 0;
cstate->off_linktype.reg = -1;
/*
* Assume it's not raw ATM with a pseudo-header, for now.
*/
cstate->is_atm = 0;
cstate->off_vpi = OFFSET_NOT_SET;
cstate->off_vci = OFFSET_NOT_SET;
cstate->off_proto = OFFSET_NOT_SET;
cstate->off_payload = OFFSET_NOT_SET;
/*
* And not Geneve.
*/
cstate->is_geneve = 0;
/*
* No variable length VLAN offset by default
*/
cstate->is_vlan_vloffset = 0;
/*
* And assume we're not doing SS7.
*/
cstate->off_li = OFFSET_NOT_SET;
cstate->off_li_hsl = OFFSET_NOT_SET;
cstate->off_sio = OFFSET_NOT_SET;
cstate->off_opc = OFFSET_NOT_SET;
cstate->off_dpc = OFFSET_NOT_SET;
cstate->off_sls = OFFSET_NOT_SET;
cstate->label_stack_depth = 0;
cstate->vlan_stack_depth = 0;
switch (cstate->linktype) {
case DLT_ARCNET:
cstate->off_linktype.constant_part = 2;
cstate->off_linkpl.constant_part = 6;
cstate->off_nl = 0; /* XXX in reality, variable! */
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_ARCNET_LINUX:
cstate->off_linktype.constant_part = 4;
cstate->off_linkpl.constant_part = 8;
cstate->off_nl = 0; /* XXX in reality, variable! */
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_EN10MB:
cstate->off_linktype.constant_part = 12;
cstate->off_linkpl.constant_part = 14; /* Ethernet header length */
cstate->off_nl = 0; /* Ethernet II */
cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
break;
case DLT_SLIP:
/*
* SLIP doesn't have a link level type. The 16 byte
* header is hacked into our SLIP driver.
*/
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 16;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_SLIP_BSDOS:
/* XXX this may be the same as the DLT_PPP_BSDOS case */
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
/* XXX end */
cstate->off_linkpl.constant_part = 24;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_NULL:
case DLT_LOOP:
cstate->off_linktype.constant_part = 0;
cstate->off_linkpl.constant_part = 4;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_ENC:
cstate->off_linktype.constant_part = 0;
cstate->off_linkpl.constant_part = 12;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_PPP:
case DLT_PPP_PPPD:
case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
cstate->off_linktype.constant_part = 2; /* skip HDLC-like framing */
cstate->off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_PPP_ETHER:
/*
* This does no include the Ethernet header, and
* only covers session state.
*/
cstate->off_linktype.constant_part = 6;
cstate->off_linkpl.constant_part = 8;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_PPP_BSDOS:
cstate->off_linktype.constant_part = 5;
cstate->off_linkpl.constant_part = 24;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_FDDI:
/*
* FDDI doesn't really have a link-level type field.
* We set "off_linktype" to the offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*/
cstate->off_linktype.constant_part = 13;
cstate->off_linktype.constant_part += cstate->pcap_fddipad;
cstate->off_linkpl.constant_part = 13; /* FDDI MAC header length */
cstate->off_linkpl.constant_part += cstate->pcap_fddipad;
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_IEEE802:
/*
* Token Ring doesn't really have a link-level type field.
* We set "off_linktype" to the offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*
* XXX - the header is actually variable-length.
* Some various Linux patched versions gave 38
* as "off_linktype" and 40 as "off_nl"; however,
* if a token ring packet has *no* routing
* information, i.e. is not source-routed, the correct
* values are 20 and 22, as they are in the vanilla code.
*
* A packet is source-routed iff the uppermost bit
* of the first byte of the source address, at an
* offset of 8, has the uppermost bit set. If the
* packet is source-routed, the total number of bytes
* of routing information is 2 plus bits 0x1F00 of
* the 16-bit value at an offset of 14 (shifted right
* 8 - figure out which byte that is).
*/
cstate->off_linktype.constant_part = 14;
cstate->off_linkpl.constant_part = 14; /* Token Ring MAC header length */
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
cstate->off_linkhdr.is_variable = 1;
/* Fall through, 802.11 doesn't have a variable link
* prefix but is otherwise the same. */
case DLT_IEEE802_11:
/*
* 802.11 doesn't really have a link-level type field.
* We set "off_linktype.constant_part" to the offset of
* the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*
* We also handle variable-length radio headers here.
* The Prism header is in theory variable-length, but in
* practice it's always 144 bytes long. However, some
* drivers on Linux use ARPHRD_IEEE80211_PRISM, but
* sometimes or always supply an AVS header, so we
* have to check whether the radio header is a Prism
* header or an AVS header, so, in practice, it's
* variable-length.
*/
cstate->off_linktype.constant_part = 24;
cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
cstate->off_linkpl.is_variable = 1;
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_PPI:
/*
* At the moment we treat PPI the same way that we treat
* normal Radiotap encoded packets. The difference is in
* the function that generates the code at the beginning
* to compute the header length. Since this code generator
* of PPI supports bare 802.11 encapsulation only (i.e.
* the encapsulated DLT should be DLT_IEEE802_11) we
* generate code to check for this too.
*/
cstate->off_linktype.constant_part = 24;
cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
cstate->off_linkpl.is_variable = 1;
cstate->off_linkhdr.is_variable = 1;
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_ATM_RFC1483:
case DLT_ATM_CLIP: /* Linux ATM defines this */
/*
* assume routed, non-ISO PDUs
* (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
*
* XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
* or PPP with the PPP NLPID (e.g., PPPoA)? The
* latter would presumably be treated the way PPPoE
* should be, so you can do "pppoe and udp port 2049"
* or "pppoa and tcp port 80" and have it check for
* PPPo{A,E} and a PPP protocol of IP and....
*/
cstate->off_linktype.constant_part = 0;
cstate->off_linkpl.constant_part = 0; /* packet begins with LLC header */
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_SUNATM:
/*
* Full Frontal ATM; you get AALn PDUs with an ATM
* pseudo-header.
*/
cstate->is_atm = 1;
cstate->off_vpi = SUNATM_VPI_POS;
cstate->off_vci = SUNATM_VCI_POS;
cstate->off_proto = PROTO_POS;
cstate->off_payload = SUNATM_PKT_BEGIN_POS;
cstate->off_linktype.constant_part = cstate->off_payload;
cstate->off_linkpl.constant_part = cstate->off_payload; /* if LLC-encapsulated */
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_RAW:
case DLT_IPV4:
case DLT_IPV6:
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 0;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
cstate->off_linktype.constant_part = 14;
cstate->off_linkpl.constant_part = 16;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_LTALK:
/*
* LocalTalk does have a 1-byte type field in the LLAP header,
* but really it just indicates whether there is a "short" or
* "long" DDP packet following.
*/
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 0;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_IP_OVER_FC:
/*
* RFC 2625 IP-over-Fibre-Channel doesn't really have a
* link-level type field. We set "off_linktype" to the
* offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP? RFC
* 2625 says SNAP should be used.
*/
cstate->off_linktype.constant_part = 16;
cstate->off_linkpl.constant_part = 16;
cstate->off_nl = 8; /* 802.2+SNAP */
cstate->off_nl_nosnap = 3; /* 802.2 */
break;
case DLT_FRELAY:
/*
* XXX - we should set this to handle SNAP-encapsulated
* frames (NLPID of 0x80).
*/
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 0;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
/*
* the only BPF-interesting FRF.16 frames are non-control frames;
* Frame Relay has a variable length link-layer
* so lets start with offset 4 for now and increments later on (FIXME);
*/
case DLT_MFR:
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 0;
cstate->off_nl = 4;
cstate->off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
break;
case DLT_APPLE_IP_OVER_IEEE1394:
cstate->off_linktype.constant_part = 16;
cstate->off_linkpl.constant_part = 18;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
case DLT_SYMANTEC_FIREWALL:
cstate->off_linktype.constant_part = 6;
cstate->off_linkpl.constant_part = 44;
cstate->off_nl = 0; /* Ethernet II */
cstate->off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
break;
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
cstate->off_linktype.constant_part = 0;
cstate->off_linkpl.constant_part = PFLOG_HDRLEN;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
break;
#endif
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_FRELAY:
cstate->off_linktype.constant_part = 4;
cstate->off_linkpl.constant_part = 4;
cstate->off_nl = 0;
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_JUNIPER_ATM1:
cstate->off_linktype.constant_part = 4; /* in reality variable between 4-8 */
cstate->off_linkpl.constant_part = 4; /* in reality variable between 4-8 */
cstate->off_nl = 0;
cstate->off_nl_nosnap = 10;
break;
case DLT_JUNIPER_ATM2:
cstate->off_linktype.constant_part = 8; /* in reality variable between 8-12 */
cstate->off_linkpl.constant_part = 8; /* in reality variable between 8-12 */
cstate->off_nl = 0;
cstate->off_nl_nosnap = 10;
break;
/* frames captured on a Juniper PPPoE service PIC
* contain raw ethernet frames */
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_ETHER:
cstate->off_linkpl.constant_part = 14;
cstate->off_linktype.constant_part = 16;
cstate->off_nl = 18; /* Ethernet II */
cstate->off_nl_nosnap = 21; /* 802.3+802.2 */
break;
case DLT_JUNIPER_PPPOE_ATM:
cstate->off_linktype.constant_part = 4;
cstate->off_linkpl.constant_part = 6;
cstate->off_nl = 0;
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_JUNIPER_GGSN:
cstate->off_linktype.constant_part = 6;
cstate->off_linkpl.constant_part = 12;
cstate->off_nl = 0;
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_JUNIPER_ES:
cstate->off_linktype.constant_part = 6;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
cstate->off_nl = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_JUNIPER_MONITOR:
cstate->off_linktype.constant_part = 12;
cstate->off_linkpl.constant_part = 12;
cstate->off_nl = 0; /* raw IP/IP6 header */
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_BACNET_MS_TP:
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_JUNIPER_SERVICES:
cstate->off_linktype.constant_part = 12;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
cstate->off_nl = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_JUNIPER_VP:
cstate->off_linktype.constant_part = 18;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_JUNIPER_ST:
cstate->off_linktype.constant_part = 18;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_JUNIPER_ISM:
cstate->off_linktype.constant_part = 8;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
cstate->off_linktype.constant_part = 8;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_MTP2:
cstate->off_li = 2;
cstate->off_li_hsl = 4;
cstate->off_sio = 3;
cstate->off_opc = 4;
cstate->off_dpc = 4;
cstate->off_sls = 7;
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_MTP2_WITH_PHDR:
cstate->off_li = 6;
cstate->off_li_hsl = 8;
cstate->off_sio = 7;
cstate->off_opc = 8;
cstate->off_dpc = 8;
cstate->off_sls = 11;
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_ERF:
cstate->off_li = 22;
cstate->off_li_hsl = 24;
cstate->off_sio = 23;
cstate->off_opc = 24;
cstate->off_dpc = 24;
cstate->off_sls = 27;
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_PFSYNC:
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = 4;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0;
break;
case DLT_AX25_KISS:
/*
* Currently, only raw "link[N:M]" filtering is supported.
*/
cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* variable, min 15, max 71 steps of 7 */
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET; /* variable, min 16, max 71 steps of 7 */
cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
break;
case DLT_IPNET:
cstate->off_linktype.constant_part = 1;
cstate->off_linkpl.constant_part = 24; /* ipnet header length */
cstate->off_nl = 0;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
break;
case DLT_NETANALYZER:
cstate->off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */
cstate->off_nl = 0; /* Ethernet II */
cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
break;
case DLT_NETANALYZER_TRANSPARENT:
cstate->off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
cstate->off_nl = 0; /* Ethernet II */
cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
break;
default:
/*
* For values in the range in which we've assigned new
* DLT_ values, only raw "link[N:M]" filtering is supported.
*/
if (cstate->linktype >= DLT_MATCHING_MIN &&
cstate->linktype <= DLT_MATCHING_MAX) {
cstate->off_linktype.constant_part = OFFSET_NOT_SET;
cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
cstate->off_nl = OFFSET_NOT_SET;
cstate->off_nl_nosnap = OFFSET_NOT_SET;
} else {
bpf_error(cstate, "unknown data link type %d", cstate->linktype);
}
break;
}
cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr;
}
/*
* Load a value relative to the specified absolute offset.
*/
static struct slist *
gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset,
u_int offset, u_int size)
{
struct slist *s, *s2;
s = gen_abs_offset_varpart(cstate, abs_offset);
/*
* If "s" is non-null, it has code to arrange that the X register
* contains the variable part of the absolute offset, so we
* generate a load relative to that, with an offset of
* abs_offset->constant_part + offset.
*
* Otherwise, we can do an absolute load with an offset of
* abs_offset->constant_part + offset.
*/
if (s != NULL) {
/*
* "s" points to a list of statements that puts the
* variable part of the absolute offset into the X register.
* Do an indirect load, to use the X register as an offset.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
s2->s.k = abs_offset->constant_part + offset;
sappend(s, s2);
} else {
/*
* There is no variable part of the absolute offset, so
* just do an absolute load.
*/
s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
s->s.k = abs_offset->constant_part + offset;
}
return s;
}
/*
* Load a value relative to the beginning of the specified header.
*/
static struct slist *
gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
u_int size)
{
struct slist *s, *s2;
switch (offrel) {
case OR_PACKET:
s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
s->s.k = offset;
break;
case OR_LINKHDR:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size);
break;
case OR_PREVLINKHDR:
s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size);
break;
case OR_LLC:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size);
break;
case OR_PREVMPLSHDR:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size);
break;
case OR_LINKPL:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size);
break;
case OR_LINKPL_NOSNAP:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size);
break;
case OR_LINKTYPE:
s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size);
break;
case OR_TRAN_IPV4:
/*
* Load the X register with the length of the IPv4 header
* (plus the offset of the link-layer header, if it's
* preceded by a variable-length header such as a radio
* header), in bytes.
*/
s = gen_loadx_iphdrlen(cstate);
/*
* Load the item at {offset of the link-layer payload} +
* {offset, relative to the start of the link-layer
* paylod, of the IPv4 header} + {length of the IPv4 header} +
* {specified offset}.
*
* If the offset of the link-layer payload is variable,
* the variable part of that offset is included in the
* value in the X register, and we include the constant
* part in the offset of the load.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset;
sappend(s, s2);
break;
case OR_TRAN_IPV6:
s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size);
break;
default:
abort();
/* NOTREACHED */
}
return s;
}
/*
* Generate code to load into the X register the sum of the length of
* the IPv4 header and the variable part of the offset of the link-layer
* payload.
*/
static struct slist *
gen_loadx_iphdrlen(compiler_state_t *cstate)
{
struct slist *s, *s2;
s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
if (s != NULL) {
/*
* The offset of the link-layer payload has a variable
* part. "s" points to a list of statements that put
* the variable part of that offset into the X register.
*
* The 4*([k]&0xf) addressing mode can't be used, as we
* don't have a constant offset, so we have to load the
* value in question into the A register and add to it
* the value from the X register.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
s2->s.k = 0xf;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
s2->s.k = 2;
sappend(s, s2);
/*
* The A register now contains the length of the IP header.
* We need to add to it the variable part of the offset of
* the link-layer payload, which is still in the X
* register, and move the result into the X register.
*/
sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
} else {
/*
* The offset of the link-layer payload is a constant,
* so no code was generated to load the (non-existent)
* variable part of that offset.
*
* This means we can use the 4*([k]&0xf) addressing
* mode. Load the length of the IPv4 header, which
* is at an offset of cstate->off_nl from the beginning of
* the link-layer payload, and thus at an offset of
* cstate->off_linkpl.constant_part + cstate->off_nl from the beginning
* of the raw packet data, using that addressing mode.
*/
s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
}
return s;
}
static struct block *
gen_uncond(compiler_state_t *cstate, int rsense)
{
struct block *b;
struct slist *s;
s = new_stmt(cstate, BPF_LD|BPF_IMM);
s->s.k = !rsense;
b = new_block(cstate, JMP(BPF_JEQ));
b->stmts = s;
return b;
}
static inline struct block *
gen_true(compiler_state_t *cstate)
{
return gen_uncond(cstate, 1);
}
static inline struct block *
gen_false(compiler_state_t *cstate)
{
return gen_uncond(cstate, 0);
}
/*
* Byte-swap a 32-bit number.
* ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
* big-endian platforms.)
*/
#define SWAPLONG(y) \
((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
/*
* Generate code to match a particular packet type.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the type/length field or to check the type/length field for
* a value <= ETHERMTU to see whether it's a type field and then do
* the appropriate test.
*/
static struct block *
gen_ether_linktype(compiler_state_t *cstate, int proto)
{
struct block *b0, *b1;
switch (proto) {
case LLCSAP_ISONS:
case LLCSAP_IP:
case LLCSAP_NETBEUI:
/*
* OSI protocols and NetBEUI always use 802.2 encapsulation,
* so we check the DSAP and SSAP.
*
* LLCSAP_IP checks for IP-over-802.2, rather
* than IP-over-Ethernet or IP-over-SNAP.
*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other types <= ETHERMTU
* (i.e., other SAP values)?
*/
b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
gen_not(b0);
b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
((proto << 8) | proto));
gen_and(b0, b1);
return b1;
case LLCSAP_IPX:
/*
* Check for;
*
* Ethernet_II frames, which are Ethernet
* frames with a frame type of ETHERTYPE_IPX;
*
* Ethernet_802.3 frames, which are 802.3
* frames (i.e., the type/length field is
* a length field, <= ETHERMTU, rather than
* a type field) with the first two bytes
* after the Ethernet/802.3 header being
* 0xFFFF;
*
* Ethernet_802.2 frames, which are 802.3
* frames with an 802.2 LLC header and
* with the IPX LSAP as the DSAP in the LLC
* header;
*
* Ethernet_SNAP frames, which are 802.3
* frames with an LLC header and a SNAP
* header and with an OUI of 0x000000
* (encapsulated Ethernet) and a protocol
* ID of ETHERTYPE_IPX in the SNAP header.
*
* XXX - should we generate the same code both
* for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
*/
/*
* This generates code to check both for the
* IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
*/
b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
gen_or(b0, b1);
/*
* Now we add code to check for SNAP frames with
* ETHERTYPE_IPX, i.e. Ethernet_SNAP.
*/
b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
gen_or(b0, b1);
/*
* Now we generate code to check for 802.3
* frames in general.
*/
b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
gen_not(b0);
/*
* Now add the check for 802.3 frames before the
* check for Ethernet_802.2 and Ethernet_802.3,
* as those checks should only be done on 802.3
* frames, not on Ethernet frames.
*/
gen_and(b0, b1);
/*
* Now add the check for Ethernet_II frames, and
* do that before checking for the other frame
* types.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
gen_or(b0, b1);
return b1;
case ETHERTYPE_ATALK:
case ETHERTYPE_AARP:
/*
* EtherTalk (AppleTalk protocols on Ethernet link
* layer) may use 802.2 encapsulation.
*/
/*
* Check for 802.2 encapsulation (EtherTalk phase 2?);
* we check for an Ethernet type field less than
* 1500, which means it's an 802.3 length field.
*/
b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
gen_not(b0);
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* 802.2-encapsulated ETHERTYPE_AARP packets are
* SNAP packets with an organization code of
* 0x000000 (encapsulated Ethernet) and a protocol
* type of ETHERTYPE_AARP (Appletalk ARP).
*/
if (proto == ETHERTYPE_ATALK)
b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
else /* proto == ETHERTYPE_AARP */
b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
gen_and(b0, b1);
/*
* Check for Ethernet encapsulation (Ethertalk
* phase 1?); we just check for the Ethernet
* protocol type.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
gen_or(b0, b1);
return b1;
default:
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so the frames
* that match would be 802.2 frames.
* Check that the frame is an 802.2 frame
* (i.e., that the length/type field is
* a length field, <= ETHERMTU) and
* then check the DSAP.
*/
b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
gen_not(b0);
b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, (bpf_int32)proto);
gen_and(b0, b1);
return b1;
} else {
/*
* This is an Ethernet type, so compare
* the length/type field with it (if
* the frame is an 802.2 frame, the length
* field will be <= ETHERMTU, and, as
* "proto" is > ETHERMTU, this test
* will fail and the frame won't match,
* which is what we want).
*/
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
(bpf_int32)proto);
}
}
}
static struct block *
gen_loopback_linktype(compiler_state_t *cstate, int proto)
{
/*
* For DLT_NULL, the link-layer header is a 32-bit word
* containing an AF_ value in *host* byte order, and for
* DLT_ENC, the link-layer header begins with a 32-bit
* word containing an AF_ value in host byte order.
*
* In addition, if we're reading a saved capture file,
* the host byte order in the capture may not be the
* same as the host byte order on this machine.
*
* For DLT_LOOP, the link-layer header is a 32-bit
* word containing an AF_ value in *network* byte order.
*/
if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) {
/*
* The AF_ value is in host byte order, but the BPF
* interpreter will convert it to network byte order.
*
* If this is a save file, and it's from a machine
* with the opposite byte order to ours, we byte-swap
* the AF_ value.
*
* Then we run it through "htonl()", and generate
* code to compare against the result.
*/
if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped)
proto = SWAPLONG(proto);
proto = htonl(proto);
}
return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, (bpf_int32)proto));
}
/*
* "proto" is an Ethernet type value and for IPNET, if it is not IPv4
* or IPv6 then we have an error.
*/
static struct block *
gen_ipnet_linktype(compiler_state_t *cstate, int proto)
{
switch (proto) {
case ETHERTYPE_IP:
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, (bpf_int32)IPH_AF_INET);
/* NOTREACHED */
case ETHERTYPE_IPV6:
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)IPH_AF_INET6);
/* NOTREACHED */
default:
break;
}
return gen_false(cstate);
}
/*
* Generate code to match a particular packet type.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the type field or to check the type field for the special
* LINUX_SLL_P_802_2 value and then do the appropriate test.
*/
static struct block *
gen_linux_sll_linktype(compiler_state_t *cstate, int proto)
{
struct block *b0, *b1;
switch (proto) {
case LLCSAP_ISONS:
case LLCSAP_IP:
case LLCSAP_NETBEUI:
/*
* OSI protocols and NetBEUI always use 802.2 encapsulation,
* so we check the DSAP and SSAP.
*
* LLCSAP_IP checks for IP-over-802.2, rather
* than IP-over-Ethernet or IP-over-SNAP.
*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other types <= ETHERMTU
* (i.e., other SAP values)?
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
((proto << 8) | proto));
gen_and(b0, b1);
return b1;
case LLCSAP_IPX:
/*
* Ethernet_II frames, which are Ethernet
* frames with a frame type of ETHERTYPE_IPX;
*
* Ethernet_802.3 frames, which have a frame
* type of LINUX_SLL_P_802_3;
*
* Ethernet_802.2 frames, which are 802.3
* frames with an 802.2 LLC header (i.e, have
* a frame type of LINUX_SLL_P_802_2) and
* with the IPX LSAP as the DSAP in the LLC
* header;
*
* Ethernet_SNAP frames, which are 802.3
* frames with an LLC header and a SNAP
* header and with an OUI of 0x000000
* (encapsulated Ethernet) and a protocol
* ID of ETHERTYPE_IPX in the SNAP header.
*
* First, do the checks on LINUX_SLL_P_802_2
* frames; generate the check for either
* Ethernet_802.2 or Ethernet_SNAP frames, and
* then put a check for LINUX_SLL_P_802_2 frames
* before it.
*/
b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
gen_or(b0, b1);
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
gen_and(b0, b1);
/*
* Now check for 802.3 frames and OR that with
* the previous test.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3);
gen_or(b0, b1);
/*
* Now add the check for Ethernet_II frames, and
* do that before checking for the other frame
* types.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
gen_or(b0, b1);
return b1;
case ETHERTYPE_ATALK:
case ETHERTYPE_AARP:
/*
* EtherTalk (AppleTalk protocols on Ethernet link
* layer) may use 802.2 encapsulation.
*/
/*
* Check for 802.2 encapsulation (EtherTalk phase 2?);
* we check for the 802.2 protocol type in the
* "Ethernet type" field.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* 802.2-encapsulated ETHERTYPE_AARP packets are
* SNAP packets with an organization code of
* 0x000000 (encapsulated Ethernet) and a protocol
* type of ETHERTYPE_AARP (Appletalk ARP).
*/
if (proto == ETHERTYPE_ATALK)
b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
else /* proto == ETHERTYPE_AARP */
b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
gen_and(b0, b1);
/*
* Check for Ethernet encapsulation (Ethertalk
* phase 1?); we just check for the Ethernet
* protocol type.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
gen_or(b0, b1);
return b1;
default:
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so the frames
* that match would be 802.2 frames.
* Check for the 802.2 protocol type
* in the "Ethernet type" field, and
* then check the DSAP.
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B,
(bpf_int32)proto);
gen_and(b0, b1);
return b1;
} else {
/*
* This is an Ethernet type, so compare
* the length/type field with it (if
* the frame is an 802.2 frame, the length
* field will be <= ETHERMTU, and, as
* "proto" is > ETHERMTU, this test
* will fail and the frame won't match,
* which is what we want).
*/
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
}
}
}
static struct slist *
gen_load_prism_llprefixlen(compiler_state_t *cstate)
{
struct slist *s1, *s2;
struct slist *sjeq_avs_cookie;
struct slist *sjcommon;
/*
* This code is not compatible with the optimizer, as
* we are generating jmp instructions within a normal
* slist of instructions
*/
cstate->no_optimize = 1;
/*
* Generate code to load the length of the radio header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*
* Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
* or always use the AVS header rather than the Prism header.
* We load a 4-byte big-endian value at the beginning of the
* raw packet data, and see whether, when masked with 0xFFFFF000,
* it's equal to 0x80211000. If so, that indicates that it's
* an AVS header (the masked-out bits are the version number).
* Otherwise, it's a Prism header.
*
* XXX - the Prism header is also, in theory, variable-length,
* but no known software generates headers that aren't 144
* bytes long.
*/
if (cstate->off_linkhdr.reg != -1) {
/*
* Load the cookie.
*/
s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
s1->s.k = 0;
/*
* AND it with 0xFFFFF000.
*/
s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
s2->s.k = 0xFFFFF000;
sappend(s1, s2);
/*
* Compare with 0x80211000.
*/
sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ));
sjeq_avs_cookie->s.k = 0x80211000;
sappend(s1, sjeq_avs_cookie);
/*
* If it's AVS:
*
* The 4 bytes at an offset of 4 from the beginning of
* the AVS header are the length of the AVS header.
* That field is big-endian.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
s2->s.k = 4;
sappend(s1, s2);
sjeq_avs_cookie->s.jt = s2;
/*
* Now jump to the code to allocate a register
* into which to save the header length and
* store the length there. (The "jump always"
* instruction needs to have the k field set;
* it's added to the PC, so, as we're jumping
* over a single instruction, it should be 1.)
*/
sjcommon = new_stmt(cstate, JMP(BPF_JA));
sjcommon->s.k = 1;
sappend(s1, sjcommon);
/*
* Now for the code that handles the Prism header.
* Just load the length of the Prism header (144)
* into the A register. Have the test for an AVS
* header branch here if we don't have an AVS header.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
s2->s.k = 144;
sappend(s1, s2);
sjeq_avs_cookie->s.jf = s2;
/*
* Now allocate a register to hold that value and store
* it. The code for the AVS header will jump here after
* loading the length of the AVS header.
*/
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkhdr.reg;
sappend(s1, s2);
sjcommon->s.jf = s2;
/*
* Now move it into the X register.
*/
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
static struct slist *
gen_load_avs_llprefixlen(compiler_state_t *cstate)
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the AVS header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
if (cstate->off_linkhdr.reg != -1) {
/*
* The 4 bytes at an offset of 4 from the beginning of
* the AVS header are the length of the AVS header.
* That field is big-endian.
*/
s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
s1->s.k = 4;
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkhdr.reg;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
static struct slist *
gen_load_radiotap_llprefixlen(compiler_state_t *cstate)
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the radiotap header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
if (cstate->off_linkhdr.reg != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* header; unfortunately, it's little-endian, so we have
* to load it a byte at a time and construct the value.
*/
/*
* Load the high-order byte, at an offset of 3, shift it
* left a byte, and put the result in the X register.
*/
s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
s1->s.k = 3;
s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
sappend(s1, s2);
s2->s.k = 8;
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
/*
* Load the next byte, at an offset of 2, and OR the
* value from the X register into it.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
sappend(s1, s2);
s2->s.k = 2;
s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
sappend(s1, s2);
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkhdr.reg;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
/*
* At the moment we treat PPI as normal Radiotap encoded
* packets. The difference is in the function that generates
* the code at the beginning to compute the header length.
* Since this code generator of PPI supports bare 802.11
* encapsulation only (i.e. the encapsulated DLT should be
* DLT_IEEE802_11) we generate code to check for this too;
* that's done in finish_parse().
*/
static struct slist *
gen_load_ppi_llprefixlen(compiler_state_t *cstate)
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the radiotap header
* into the register assigned to hold that length, if one has
* been assigned.
*/
if (cstate->off_linkhdr.reg != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* header; unfortunately, it's little-endian, so we have
* to load it a byte at a time and construct the value.
*/
/*
* Load the high-order byte, at an offset of 3, shift it
* left a byte, and put the result in the X register.
*/
s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
s1->s.k = 3;
s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
sappend(s1, s2);
s2->s.k = 8;
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
/*
* Load the next byte, at an offset of 2, and OR the
* value from the X register into it.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
sappend(s1, s2);
s2->s.k = 2;
s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
sappend(s1, s2);
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkhdr.reg;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
/*
* Load a value relative to the beginning of the link-layer header after the 802.11
* header, i.e. LLC_SNAP.
* The link-layer header doesn't necessarily begin at the beginning
* of the packet data; there might be a variable-length prefix containing
* radio information.
*/
static struct slist *
gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext)
{
struct slist *s2;
struct slist *sjset_data_frame_1;
struct slist *sjset_data_frame_2;
struct slist *sjset_qos;
struct slist *sjset_radiotap_flags_present;
struct slist *sjset_radiotap_ext_present;
struct slist *sjset_radiotap_tsft_present;
struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
struct slist *s_roundup;
if (cstate->off_linkpl.reg == -1) {
/*
* No register has been assigned to the offset of
* the link-layer payload, which means nobody needs
* it; don't bother computing it - just return
* what we already have.
*/
return (s);
}
/*
* This code is not compatible with the optimizer, as
* we are generating jmp instructions within a normal
* slist of instructions
*/
cstate->no_optimize = 1;
/*
* If "s" is non-null, it has code to arrange that the X register
* contains the length of the prefix preceding the link-layer
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
* header is "off_outermostlinkhdr.constant_part".
*/
if (s == NULL) {
/*
* There is no variable-length header preceding the
* link-layer header.
*
* Load the length of the fixed-length prefix preceding
* the link-layer header (if any) into the X register,
* and store it in the cstate->off_linkpl.reg register.
* That length is off_outermostlinkhdr.constant_part.
*/
s = new_stmt(cstate, BPF_LDX|BPF_IMM);
s->s.k = cstate->off_outermostlinkhdr.constant_part;
}
/*
* The X register contains the offset of the beginning of the
* link-layer header; add 24, which is the minimum length
* of the MAC header for a data frame, to that, and store it
* in cstate->off_linkpl.reg, and then load the Frame Control field,
* which is at the offset in the X register, with an indexed load.
*/
s2 = new_stmt(cstate, BPF_MISC|BPF_TXA);
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s2->s.k = 24;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkpl.reg;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s2->s.k = 0;
sappend(s, s2);
/*
* Check the Frame Control field to see if this is a data frame;
* a data frame has the 0x08 bit (b3) in that field set and the
* 0x04 bit (b2) clear.
*/
sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET));
sjset_data_frame_1->s.k = 0x08;
sappend(s, sjset_data_frame_1);
/*
* If b3 is set, test b2, otherwise go to the first statement of
* the rest of the program.
*/
sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET));
sjset_data_frame_2->s.k = 0x04;
sappend(s, sjset_data_frame_2);
sjset_data_frame_1->s.jf = snext;
/*
* If b2 is not set, this is a data frame; test the QoS bit.
* Otherwise, go to the first statement of the rest of the
* program.
*/
sjset_data_frame_2->s.jt = snext;
sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET));
sjset_qos->s.k = 0x80; /* QoS bit */
sappend(s, sjset_qos);
/*
* If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS
* field.
* Otherwise, go to the first statement of the rest of the
* program.
*/
sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
s2->s.k = cstate->off_linkpl.reg;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 2;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkpl.reg;
sappend(s, s2);
/*
* If we have a radiotap header, look at it to see whether
* there's Atheros padding between the MAC-layer header
* and the payload.
*
* Note: all of the fields in the radiotap header are
* little-endian, so we byte-swap all of the values
* we test against, as they will be loaded as big-endian
* values.
*
* XXX - in the general case, we would have to scan through
* *all* the presence bits, if there's more than one word of
* presence bits. That would require a loop, meaning that
* we wouldn't be able to run the filter in the kernel.
*
* We assume here that the Atheros adapters that insert the
* annoying padding don't have multiple antennae and therefore
* do not generate radiotap headers with multiple presence words.
*/
if (cstate->linktype == DLT_IEEE802_11_RADIO) {
/*
* Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
* in the first presence flag word?
*/
sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W);
s2->s.k = 4;
sappend(s, s2);
sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET));
sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002);
sappend(s, sjset_radiotap_flags_present);
/*
* If not, skip all of this.
*/
sjset_radiotap_flags_present->s.jf = snext;
/*
* Otherwise, is the "extension" bit set in that word?
*/
sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET));
sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000);
sappend(s, sjset_radiotap_ext_present);
sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present;
/*
* If so, skip all of this.
*/
sjset_radiotap_ext_present->s.jt = snext;
/*
* Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
*/
sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET));
sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001);
sappend(s, sjset_radiotap_tsft_present);
sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present;
/*
* If IEEE80211_RADIOTAP_TSFT is set, the flags field is
* at an offset of 16 from the beginning of the raw packet
* data (8 bytes for the radiotap header and 8 bytes for
* the TSFT field).
*
* Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
* is set.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
s2->s.k = 16;
sappend(s, s2);
sjset_radiotap_tsft_present->s.jt = s2;
sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
sjset_tsft_datapad->s.k = 0x20;
sappend(s, sjset_tsft_datapad);
/*
* If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
* at an offset of 8 from the beginning of the raw packet
* data (8 bytes for the radiotap header).
*
* Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
* is set.
*/
s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
s2->s.k = 8;
sappend(s, s2);
sjset_radiotap_tsft_present->s.jf = s2;
sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
sjset_notsft_datapad->s.k = 0x20;
sappend(s, sjset_notsft_datapad);
/*
* In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
* set, round the length of the 802.11 header to
* a multiple of 4. Do that by adding 3 and then
* dividing by and multiplying by 4, which we do by
* ANDing with ~3.
*/
s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM);
s_roundup->s.k = cstate->off_linkpl.reg;
sappend(s, s_roundup);
s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 3;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM);
s2->s.k = ~3;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkpl.reg;
sappend(s, s2);
sjset_tsft_datapad->s.jt = s_roundup;
sjset_tsft_datapad->s.jf = snext;
sjset_notsft_datapad->s.jt = s_roundup;
sjset_notsft_datapad->s.jf = snext;
} else
sjset_qos->s.jf = snext;
return s;
}
static void
insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
{
struct slist *s;
/* There is an implicit dependency between the link
* payload and link header since the payload computation
* includes the variable part of the header. Therefore,
* if nobody else has allocated a register for the link
* header and we need it, do it now. */
if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable &&
cstate->off_linkhdr.reg == -1)
cstate->off_linkhdr.reg = alloc_reg(cstate);
/*
* For link-layer types that have a variable-length header
* preceding the link-layer header, generate code to load
* the offset of the link-layer header into the register
* assigned to that offset, if any.
*
* XXX - this, and the next switch statement, won't handle
* encapsulation of 802.11 or 802.11+radio information in
* some other protocol stack. That's significantly more
* complicated.
*/
switch (cstate->outermostlinktype) {
case DLT_PRISM_HEADER:
s = gen_load_prism_llprefixlen(cstate);
break;
case DLT_IEEE802_11_RADIO_AVS:
s = gen_load_avs_llprefixlen(cstate);
break;
case DLT_IEEE802_11_RADIO:
s = gen_load_radiotap_llprefixlen(cstate);
break;
case DLT_PPI:
s = gen_load_ppi_llprefixlen(cstate);
break;
default:
s = NULL;
break;
}
/*
* For link-layer types that have a variable-length link-layer
* header, generate code to load the offset of the link-layer
* payload into the register assigned to that offset, if any.
*/
switch (cstate->outermostlinktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
s = gen_load_802_11_header_len(cstate, s, b->stmts);
break;
}
/*
* If there there is no initialization yet and we need variable
* length offsets for VLAN, initialize them to zero
*/
if (s == NULL && cstate->is_vlan_vloffset) {
struct slist *s2;
if (cstate->off_linkpl.reg == -1)
cstate->off_linkpl.reg = alloc_reg(cstate);
if (cstate->off_linktype.reg == -1)
cstate->off_linktype.reg = alloc_reg(cstate);
s = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
s->s.k = 0;
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linkpl.reg;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = cstate->off_linktype.reg;
sappend(s, s2);
}
/*
* If we have any offset-loading code, append all the
* existing statements in the block to those statements,
* and make the resulting list the list of statements
* for the block.
*/
if (s != NULL) {
sappend(s, b->stmts);
b->stmts = s;
}
}
static struct block *
gen_ppi_dlt_check(compiler_state_t *cstate)
{
struct slist *s_load_dlt;
struct block *b;
if (cstate->linktype == DLT_PPI)
{
/* Create the statements that check for the DLT
*/
s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
s_load_dlt->s.k = 4;
b = new_block(cstate, JMP(BPF_JEQ));
b->stmts = s_load_dlt;
b->s.k = SWAPLONG(DLT_IEEE802_11);
}
else
{
b = NULL;
}
return b;
}
/*
* Take an absolute offset, and:
*
* if it has no variable part, return NULL;
*
* if it has a variable part, generate code to load the register
* containing that variable part into the X register, returning
* a pointer to that code - if no register for that offset has
* been allocated, allocate it first.
*
* (The code to set that register will be generated later, but will
* be placed earlier in the code sequence.)
*/
static struct slist *
gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off)
{
struct slist *s;
if (off->is_variable) {
if (off->reg == -1) {
/*
* We haven't yet assigned a register for the
* variable part of the offset of the link-layer
* header; allocate one.
*/
off->reg = alloc_reg(cstate);
}
/*
* Load the register containing the variable part of the
* offset of the link-layer header into the X register.
*/
s = new_stmt(cstate, BPF_LDX|BPF_MEM);
s->s.k = off->reg;
return s;
} else {
/*
* That offset isn't variable, there's no variable part,
* so we don't need to generate any code.
*/
return NULL;
}
}
/*
* Map an Ethernet type to the equivalent PPP type.
*/
static int
ethertype_to_ppptype(int proto)
{
switch (proto) {
case ETHERTYPE_IP:
proto = PPP_IP;
break;
case ETHERTYPE_IPV6:
proto = PPP_IPV6;
break;
case ETHERTYPE_DN:
proto = PPP_DECNET;
break;
case ETHERTYPE_ATALK:
proto = PPP_APPLE;
break;
case ETHERTYPE_NS:
proto = PPP_NS;
break;
case LLCSAP_ISONS:
proto = PPP_OSI;
break;
case LLCSAP_8021D:
/*
* I'm assuming the "Bridging PDU"s that go
* over PPP are Spanning Tree Protocol
* Bridging PDUs.
*/
proto = PPP_BRPDU;
break;
case LLCSAP_IPX:
proto = PPP_IPX;
break;
}
return (proto);
}
/*
* Generate any tests that, for encapsulation of a link-layer packet
* inside another protocol stack, need to be done to check for those
* link-layer packets (and that haven't already been done by a check
* for that encapsulation).
*/
static struct block *
gen_prevlinkhdr_check(compiler_state_t *cstate)
{
struct block *b0;
if (cstate->is_geneve)
return gen_geneve_ll_check(cstate);
switch (cstate->prevlinktype) {
case DLT_SUNATM:
/*
* This is LANE-encapsulated Ethernet; check that the LANE
* packet doesn't begin with an LE Control marker, i.e.
* that it's data, not a control message.
*
* (We've already generated a test for LANE.)
*/
b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00);
gen_not(b0);
return b0;
default:
/*
* No such tests are necessary.
*/
return NULL;
}
/*NOTREACHED*/
}
/*
* The three different values we should check for when checking for an
* IPv6 packet with DLT_NULL.
*/
#define BSD_AFNUM_INET6_BSD 24 /* NetBSD, OpenBSD, BSD/OS, Npcap */
#define BSD_AFNUM_INET6_FREEBSD 28 /* FreeBSD */
#define BSD_AFNUM_INET6_DARWIN 30 /* macOS, iOS, other Darwin-based OSes */
/*
* Generate code to match a particular packet type by matching the
* link-layer type field or fields in the 802.2 LLC header.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU.
*/
static struct block *
gen_linktype(compiler_state_t *cstate, int proto)
{
struct block *b0, *b1, *b2;
const char *description;
/* are we checking MPLS-encapsulated packets? */
if (cstate->label_stack_depth > 0) {
switch (proto) {
case ETHERTYPE_IP:
case PPP_IP:
/* FIXME add other L3 proto IDs */
return gen_mpls_linktype(cstate, Q_IP);
case ETHERTYPE_IPV6:
case PPP_IPV6:
/* FIXME add other L3 proto IDs */
return gen_mpls_linktype(cstate, Q_IPV6);
default:
bpf_error(cstate, "unsupported protocol over mpls");
/* NOTREACHED */
}
}
switch (cstate->linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
/* Geneve has an EtherType regardless of whether there is an
* L2 header. */
if (!cstate->is_geneve)
b0 = gen_prevlinkhdr_check(cstate);
else
b0 = NULL;
b1 = gen_ether_linktype(cstate, proto);
if (b0 != NULL)
gen_and(b0, b1);
return b1;
/*NOTREACHED*/
break;
case DLT_C_HDLC:
switch (proto) {
case LLCSAP_ISONS:
proto = (proto << 8 | LLCSAP_ISONS);
/* fall through */
default:
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
/*NOTREACHED*/
break;
}
break;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
/*
* Check that we have a data frame.
*/
b0 = gen_check_802_11_data_frame(cstate);
/*
* Now check for the specified link-layer type.
*/
b1 = gen_llc_linktype(cstate, proto);
gen_and(b0, b1);
return b1;
/*NOTREACHED*/
break;
case DLT_FDDI:
/*
* XXX - check for LLC frames.
*/
return gen_llc_linktype(cstate, proto);
/*NOTREACHED*/
break;
case DLT_IEEE802:
/*
* XXX - check for LLC PDUs, as per IEEE 802.5.
*/
return gen_llc_linktype(cstate, proto);
/*NOTREACHED*/
break;
case DLT_ATM_RFC1483:
case DLT_ATM_CLIP:
case DLT_IP_OVER_FC:
return gen_llc_linktype(cstate, proto);
/*NOTREACHED*/
break;
case DLT_SUNATM:
/*
* Check for an LLC-encapsulated version of this protocol;
* if we were checking for LANE, linktype would no longer
* be DLT_SUNATM.
*
* Check for LLC encapsulation and then check the protocol.
*/
b0 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
b1 = gen_llc_linktype(cstate, proto);
gen_and(b0, b1);
return b1;
/*NOTREACHED*/
break;
case DLT_LINUX_SLL:
return gen_linux_sll_linktype(cstate, proto);
/*NOTREACHED*/
break;
case DLT_SLIP:
case DLT_SLIP_BSDOS:
case DLT_RAW:
/*
* These types don't provide any type field; packets
* are always IPv4 or IPv6.
*
* XXX - for IPv4, check for a version number of 4, and,
* for IPv6, check for a version number of 6?
*/
switch (proto) {
case ETHERTYPE_IP:
/* Check for a version number of 4. */
return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0);
case ETHERTYPE_IPV6:
/* Check for a version number of 6. */
return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0);
default:
return gen_false(cstate); /* always false */
}
/*NOTREACHED*/
break;
case DLT_IPV4:
/*
* Raw IPv4, so no type field.
*/
if (proto == ETHERTYPE_IP)
return gen_true(cstate); /* always true */
/* Checking for something other than IPv4; always false */
return gen_false(cstate);
/*NOTREACHED*/
break;
case DLT_IPV6:
/*
* Raw IPv6, so no type field.
*/
if (proto == ETHERTYPE_IPV6)
return gen_true(cstate); /* always true */
/* Checking for something other than IPv6; always false */
return gen_false(cstate);
/*NOTREACHED*/
break;
case DLT_PPP:
case DLT_PPP_PPPD:
case DLT_PPP_SERIAL:
case DLT_PPP_ETHER:
/*
* We use Ethernet protocol types inside libpcap;
* map them to the corresponding PPP protocol types.
*/
proto = ethertype_to_ppptype(proto);
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
/*NOTREACHED*/
break;
case DLT_PPP_BSDOS:
/*
* We use Ethernet protocol types inside libpcap;
* map them to the corresponding PPP protocol types.
*/
switch (proto) {
case ETHERTYPE_IP:
/*
* Also check for Van Jacobson-compressed IP.
* XXX - do this for other forms of PPP?
*/
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP);
b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC);
gen_or(b0, b1);
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC);
gen_or(b1, b0);
return b0;
default:
proto = ethertype_to_ppptype(proto);
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
(bpf_int32)proto);
}
/*NOTREACHED*/
break;
case DLT_NULL:
case DLT_LOOP:
case DLT_ENC:
switch (proto) {
case ETHERTYPE_IP:
return (gen_loopback_linktype(cstate, AF_INET));
case ETHERTYPE_IPV6:
/*
* AF_ values may, unfortunately, be platform-
* dependent; AF_INET isn't, because everybody
* used 4.2BSD's value, but AF_INET6 is, because
* 4.2BSD didn't have a value for it (given that
* IPv6 didn't exist back in the early 1980's),
* and they all picked their own values.
*
* This means that, if we're reading from a
* savefile, we need to check for all the
* possible values.
*
* If we're doing a live capture, we only need
* to check for this platform's value; however,
* Npcap uses 24, which isn't Windows's AF_INET6
* value. (Given the multiple different values,
* programs that read pcap files shouldn't be
* checking for their platform's AF_INET6 value
* anyway, they should check for all of the
* possible values. and they might as well do
* that even for live captures.)
*/
if (cstate->bpf_pcap->rfile != NULL) {
/*
* Savefile - check for all three
* possible IPv6 values.
*/
b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD);
b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD);
gen_or(b0, b1);
b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN);
gen_or(b0, b1);
return (b1);
} else {
/*
* Live capture, so we only need to
* check for the value used on this
* platform.
*/
#ifdef _WIN32
/*
* Npcap doesn't use Windows's AF_INET6,
* as that collides with AF_IPX on
* some BSDs (both have the value 23).
* Instead, it uses 24.
*/
return (gen_loopback_linktype(cstate, 24));
#else /* _WIN32 */
#ifdef AF_INET6
return (gen_loopback_linktype(cstate, AF_INET6));
#else /* AF_INET6 */
/*
* I guess this platform doesn't support
* IPv6, so we just reject all packets.
*/
return gen_false(cstate);
#endif /* AF_INET6 */
#endif /* _WIN32 */
}
default:
/*
* Not a type on which we support filtering.
* XXX - support those that have AF_ values
* #defined on this platform, at least?
*/
return gen_false(cstate);
}
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
/*
* af field is host byte order in contrast to the rest of
* the packet.
*/
if (proto == ETHERTYPE_IP)
return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
BPF_B, (bpf_int32)AF_INET));
else if (proto == ETHERTYPE_IPV6)
return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
BPF_B, (bpf_int32)AF_INET6));
else
return gen_false(cstate);
/*NOTREACHED*/
break;
#endif /* HAVE_NET_PFVAR_H */
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
/*
* XXX should we check for first fragment if the protocol
* uses PHDS?
*/
switch (proto) {
default:
return gen_false(cstate);
case ETHERTYPE_IPV6:
return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_INET6));
case ETHERTYPE_IP:
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_IP);
b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_IP_OLD);
gen_or(b0, b1);
return (b1);
case ETHERTYPE_ARP:
b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_ARP);
b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_ARP_OLD);
gen_or(b0, b1);
return (b1);
case ETHERTYPE_REVARP:
return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_REVARP));
case ETHERTYPE_ATALK:
return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
(bpf_int32)ARCTYPE_ATALK));
}
/*NOTREACHED*/
break;
case DLT_LTALK:
switch (proto) {
case ETHERTYPE_ATALK:
return gen_true(cstate);
default:
return gen_false(cstate);
}
/*NOTREACHED*/
break;
case DLT_FRELAY:
/*
* XXX - assumes a 2-byte Frame Relay header with
* DLCI and flags. What if the address is longer?
*/
switch (proto) {
case ETHERTYPE_IP:
/*
* Check for the special NLPID for IP.
*/
return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc);
case ETHERTYPE_IPV6:
/*
* Check for the special NLPID for IPv6.
*/
return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e);
case LLCSAP_ISONS:
/*
* Check for several OSI protocols.
*
* Frame Relay packets typically have an OSI
* NLPID at the beginning; we check for each
* of them.
*
* What we check for is the NLPID and a frame
* control field of UI, i.e. 0x03 followed
* by the NLPID.
*/
b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
gen_or(b1, b2);
gen_or(b0, b2);
return b2;
default:
return gen_false(cstate);
}
/*NOTREACHED*/
break;
case DLT_MFR:
bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented");
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_ATM1:
case DLT_JUNIPER_ATM2:
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_PPPOE_ATM:
case DLT_JUNIPER_GGSN:
case DLT_JUNIPER_ES:
case DLT_JUNIPER_MONITOR:
case DLT_JUNIPER_SERVICES:
case DLT_JUNIPER_ETHER:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_FRELAY:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_VP:
case DLT_JUNIPER_ST:
case DLT_JUNIPER_ISM:
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
/* just lets verify the magic number for now -
* on ATM we may have up to 6 different encapsulations on the wire
* and need a lot of heuristics to figure out that the payload
* might be;
*
* FIXME encapsulation specific BPF_ filters
*/
return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
case DLT_BACNET_MS_TP:
return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000);
case DLT_IPNET:
return gen_ipnet_linktype(cstate, proto);
case DLT_LINUX_IRDA:
bpf_error(cstate, "IrDA link-layer type filtering not implemented");
case DLT_DOCSIS:
bpf_error(cstate, "DOCSIS link-layer type filtering not implemented");
case DLT_MTP2:
case DLT_MTP2_WITH_PHDR:
bpf_error(cstate, "MTP2 link-layer type filtering not implemented");
case DLT_ERF:
bpf_error(cstate, "ERF link-layer type filtering not implemented");
case DLT_PFSYNC:
bpf_error(cstate, "PFSYNC link-layer type filtering not implemented");
case DLT_LINUX_LAPD:
bpf_error(cstate, "LAPD link-layer type filtering not implemented");
case DLT_USB_FREEBSD:
case DLT_USB_LINUX:
case DLT_USB_LINUX_MMAPPED:
case DLT_USBPCAP:
bpf_error(cstate, "USB link-layer type filtering not implemented");
case DLT_BLUETOOTH_HCI_H4:
case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
bpf_error(cstate, "Bluetooth link-layer type filtering not implemented");
case DLT_CAN20B:
case DLT_CAN_SOCKETCAN:
bpf_error(cstate, "CAN link-layer type filtering not implemented");
case DLT_IEEE802_15_4:
case DLT_IEEE802_15_4_LINUX:
case DLT_IEEE802_15_4_NONASK_PHY:
case DLT_IEEE802_15_4_NOFCS:
bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented");
case DLT_IEEE802_16_MAC_CPS_RADIO:
bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented");
case DLT_SITA:
bpf_error(cstate, "SITA link-layer type filtering not implemented");
case DLT_RAIF1:
bpf_error(cstate, "RAIF1 link-layer type filtering not implemented");
case DLT_IPMB:
bpf_error(cstate, "IPMB link-layer type filtering not implemented");
case DLT_AX25_KISS:
bpf_error(cstate, "AX.25 link-layer type filtering not implemented");
case DLT_NFLOG:
/* Using the fixed-size NFLOG header it is possible to tell only
* the address family of the packet, other meaningful data is
* either missing or behind TLVs.
*/
bpf_error(cstate, "NFLOG link-layer type filtering not implemented");
default:
/*
* Does this link-layer header type have a field
* indicating the type of the next protocol? If
* so, off_linktype.constant_part will be the offset of that
* field in the packet; if not, it will be OFFSET_NOT_SET.
*/
if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) {
/*
* Yes; assume it's an Ethernet type. (If
* it's not, it needs to be handled specially
* above.)
*/
return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
} else {
/*
* No; report an error.
*/
description = pcap_datalink_val_to_description(cstate->linktype);
if (description != NULL) {
bpf_error(cstate, "%s link-layer type filtering not implemented",
description);
} else {
bpf_error(cstate, "DLT %u link-layer type filtering not implemented",
cstate->linktype);
}
}
break;
}
}
/*
* Check for an LLC SNAP packet with a given organization code and
* protocol type; we check the entire contents of the 802.2 LLC and
* snap headers, checking for DSAP and SSAP of SNAP and a control
* field of 0x03 in the LLC header, and for the specified organization
* code and protocol type in the SNAP header.
*/
static struct block *
gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype)
{
u_char snapblock[8];
snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
snapblock[2] = 0x03; /* control = UI */
snapblock[3] = (u_char)(orgcode >> 16); /* upper 8 bits of organization code */
snapblock[4] = (u_char)(orgcode >> 8); /* middle 8 bits of organization code */
snapblock[5] = (u_char)(orgcode >> 0); /* lower 8 bits of organization code */
snapblock[6] = (u_char)(ptype >> 8); /* upper 8 bits of protocol type */
snapblock[7] = (u_char)(ptype >> 0); /* lower 8 bits of protocol type */
return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock);
}
/*
* Generate code to match frames with an LLC header.
*/
struct block *
gen_llc(compiler_state_t *cstate)
{
struct block *b0, *b1;
switch (cstate->linktype) {
case DLT_EN10MB:
/*
* We check for an Ethernet type field less than
* 1500, which means it's an 802.3 length field.
*/
b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
gen_not(b0);
/*
* Now check for the purported DSAP and SSAP not being
* 0xFF, to rule out NetWare-over-802.3.
*/
b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
gen_not(b1);
gen_and(b0, b1);
return b1;
case DLT_SUNATM:
/*
* We check for LLC traffic.
*/
b0 = gen_atmtype_abbrev(cstate, A_LLC);
return b0;
case DLT_IEEE802: /* Token Ring */
/*
* XXX - check for LLC frames.
*/
return gen_true(cstate);
case DLT_FDDI:
/*
* XXX - check for LLC frames.
*/
return gen_true(cstate);
case DLT_ATM_RFC1483:
/*
* For LLC encapsulation, these are defined to have an
* 802.2 LLC header.
*
* For VC encapsulation, they don't, but there's no
* way to check for that; the protocol used on the VC
* is negotiated out of band.
*/
return gen_true(cstate);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_PPI:
/*
* Check that we have a data frame.
*/
b0 = gen_check_802_11_data_frame(cstate);
return b0;
default:
bpf_error(cstate, "'llc' not supported for linktype %d", cstate->linktype);
/* NOTREACHED */
}
}
struct block *
gen_llc_i(compiler_state_t *cstate)
{
struct block *b0, *b1;
struct slist *s;
/*
* Check whether this is an LLC frame.
*/
b0 = gen_llc(cstate);
/*
* Load the control byte and test the low-order bit; it must
* be clear for I frames.
*/
s = gen_load_a(cstate, OR_LLC, 2, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x01;
b1->stmts = s;
gen_not(b1);
gen_and(b0, b1);
return b1;
}
struct block *
gen_llc_s(compiler_state_t *cstate)
{
struct block *b0, *b1;
/*
* Check whether this is an LLC frame.
*/
b0 = gen_llc(cstate);
/*
* Now compare the low-order 2 bit of the control byte against
* the appropriate value for S frames.
*/
b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03);
gen_and(b0, b1);
return b1;
}
struct block *
gen_llc_u(compiler_state_t *cstate)
{
struct block *b0, *b1;
/*
* Check whether this is an LLC frame.
*/
b0 = gen_llc(cstate);
/*
* Now compare the low-order 2 bit of the control byte against
* the appropriate value for U frames.
*/
b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03);
gen_and(b0, b1);
return b1;
}
struct block *
gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
{
struct block *b0, *b1;
/*
* Check whether this is an LLC frame.
*/
b0 = gen_llc(cstate);
/*
* Now check for an S frame with the appropriate type.
*/
b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK);
gen_and(b0, b1);
return b1;
}
struct block *
gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
{
struct block *b0, *b1;
/*
* Check whether this is an LLC frame.
*/
b0 = gen_llc(cstate);
/*
* Now check for a U frame with the appropriate type.
*/
b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK);
gen_and(b0, b1);
return b1;
}
/*
* Generate code to match a particular packet type, for link-layer types
* using 802.2 LLC headers.
*
* This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
* for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the DSAP or both DSAP and LSAP or to check the OUI and
* protocol ID in a SNAP header.
*/
static struct block *
gen_llc_linktype(compiler_state_t *cstate, int proto)
{
/*
* XXX - handle token-ring variable-length header.
*/
switch (proto) {
case LLCSAP_IP:
case LLCSAP_ISONS:
case LLCSAP_NETBEUI:
/*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other SAP values?
*/
return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32)
((proto << 8) | proto));
case LLCSAP_IPX:
/*
* XXX - are there ever SNAP frames for IPX on
* non-Ethernet 802.x networks?
*/
return gen_cmp(cstate, OR_LLC, 0, BPF_B,
(bpf_int32)LLCSAP_IPX);
case ETHERTYPE_ATALK:
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* XXX - check for an organization code of
* encapsulated Ethernet as well?
*/
return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
default:
/*
* XXX - we don't have to check for IPX 802.3
* here, but should we check for the IPX Ethertype?
*/
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so check
* the DSAP.
*/
return gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)proto);
} else {
/*
* This is an Ethernet type; we assume that it's
* unlikely that it'll appear in the right place
* at random, and therefore check only the
* location that would hold the Ethernet type
* in a SNAP frame with an organization code of
* 0x000000 (encapsulated Ethernet).
*
* XXX - if we were to check for the SNAP DSAP and
* LSAP, as per XXX, and were also to check for an
* organization code of 0x000000 (encapsulated
* Ethernet), we'd do
*
* return gen_snap(cstate, 0x000000, proto);
*
* here; for now, we don't, as per the above.
* I don't know whether it's worth the extra CPU
* time to do the right check or not.
*/
return gen_cmp(cstate, OR_LLC, 6, BPF_H, (bpf_int32)proto);
}
}
}
static struct block *
gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
int dir, int proto, u_int src_off, u_int dst_off)
{
struct block *b0, *b1;
u_int offset;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_RA:
bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
break;
case Q_TA:
bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
break;
default:
abort();
}
b0 = gen_linktype(cstate, proto);
b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, (bpf_int32)addr, mask);
gen_and(b0, b1);
return b1;
}
#ifdef INET6
static struct block *
gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off)
{
struct block *b0, *b1;
u_int offset;
uint32_t *a, *m;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
break;
case Q_RA:
bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
break;
case Q_TA:
bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
break;
default:
abort();
}
/* this order is important */
a = (uint32_t *)addr;
m = (uint32_t *)mask;
b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
gen_and(b0, b1);
b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
gen_and(b0, b1);
b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
gen_and(b0, b1);
b0 = gen_linktype(cstate, proto);
gen_and(b0, b1);
return b1;
}
#endif
static struct block *
gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
case Q_DST:
return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
case Q_AND:
b0 = gen_ehostop(cstate, eaddr, Q_SRC);
b1 = gen_ehostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ehostop(cstate, eaddr, Q_SRC);
b1 = gen_ehostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11 with 802.11 headers");
break;
case Q_RA:
bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers");
break;
case Q_TA:
bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_FDDI
*/
static struct block *
gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
case Q_DST:
return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
case Q_AND:
b0 = gen_fhostop(cstate, eaddr, Q_SRC);
b1 = gen_fhostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_fhostop(cstate, eaddr, Q_SRC);
b1 = gen_fhostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
break;
case Q_RA:
bpf_error(cstate, "'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error(cstate, "'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
*/
static struct block *
gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
case Q_DST:
return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
case Q_AND:
b0 = gen_thostop(cstate, eaddr, Q_SRC);
b1 = gen_thostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_thostop(cstate, eaddr, Q_SRC);
b1 = gen_thostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
break;
case Q_RA:
bpf_error(cstate, "'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error(cstate, "'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
* various 802.11 + radio headers.
*/
static struct block *
gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
register struct block *b0, *b1, *b2;
register struct slist *s;
#ifdef ENABLE_WLAN_FILTERING_PATCH
/*
* TODO GV 20070613
* We need to disable the optimizer because the optimizer is buggy
* and wipes out some LD instructions generated by the below
* code to validate the Frame Control bits
*/
cstate->no_optimize = 1;
#endif /* ENABLE_WLAN_FILTERING_PATCH */
switch (dir) {
case Q_SRC:
/*
* Oh, yuk.
*
* For control frames, there is no SA.
*
* For management frames, SA is at an
* offset of 10 from the beginning of
* the packet.
*
* For data frames, SA is at an offset
* of 10 from the beginning of the packet
* if From DS is clear, at an offset of
* 16 from the beginning of the packet
* if From DS is set and To DS is clear,
* and an offset of 24 from the beginning
* of the packet if From DS is set and To DS
* is set.
*/
/*
* Generate the tests to be done for data frames
* with From DS set.
*
* First, check for To DS set, i.e. check "link[1] & 0x01".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the SA is at 24.
*/
b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the SA is at 16.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames with
* From DS set.
*/
gen_or(b1, b0);
/*
* Now check for From DS being set, and AND that with
* the ORed-together checks.
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x02; /* From DS */
b1->stmts = s;
gen_and(b1, b0);
/*
* Now check for data frames with From DS not set.
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x02; /* From DS */
b2->stmts = s;
gen_not(b2);
/*
* If From DS isn't set, the SA is at 10.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the checks for data frames with
* From DS not set and for data frames with From DS
* set; that gives the checks done for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the SA is at 10.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case Q_DST:
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case Q_RA:
/*
* Not present in management frames; addr1 in other
* frames.
*/
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "(link[0] & 0x08)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* Check addr1.
*/
b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
/*
* AND that with the check of addr1.
*/
gen_and(b1, b0);
return (b0);
case Q_TA:
/*
* Not present in management frames; addr2, if present,
* in other frames.
*/
/*
* Not present in CTS or ACK control frames.
*/
b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b1);
b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b2);
gen_and(b1, b2);
gen_or(b0, b2);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "(link[0] & 0x08)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the check for frames other than
* CTS and ACK frames.
*/
gen_and(b1, b2);
/*
* Check addr2.
*/
b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
gen_and(b2, b1);
return b1;
/*
* XXX - add BSSID keyword?
*/
case Q_ADDR1:
return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr));
case Q_ADDR2:
/*
* Not present in CTS or ACK control frames.
*/
b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b1);
b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b2);
gen_and(b1, b2);
gen_or(b0, b2);
b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
gen_and(b2, b1);
return b1;
case Q_ADDR3:
/*
* Not present in control frames.
*/
b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
gen_and(b0, b1);
return b1;
case Q_ADDR4:
/*
* Present only if the direction mask has both "From DS"
* and "To DS" set. Neither control frames nor management
* frames should have both of those set, so we don't
* check the frame type.
*/
b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B,
IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
gen_and(b0, b1);
return b1;
case Q_AND:
b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
* (We assume that the addresses are IEEE 48-bit MAC addresses,
* as the RFC states.)
*/
static struct block *
gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
case Q_DST:
return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
case Q_AND:
b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
break;
case Q_RA:
bpf_error(cstate, "'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error(cstate, "'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* This is quite tricky because there may be pad bytes in front of the
* DECNET header, and then there are two possible data packet formats that
* carry both src and dst addresses, plus 5 packet types in a format that
* carries only the src node, plus 2 types that use a different format and
* also carry just the src node.
*
* Yuck.
*
* Instead of doing those all right, we just look for data packets with
* 0 or 1 bytes of padding. If you want to look at other packets, that
* will require a lot more hacking.
*
* To add support for filtering on DECNET "areas" (network numbers)
* one would want to add a "mask" argument to this routine. That would
* make the filter even more inefficient, although one could be clever
* and not generate masking instructions if the mask is 0xFFFF.
*/
static struct block *
gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir)
{
struct block *b0, *b1, *b2, *tmp;
u_int offset_lh; /* offset if long header is received */
u_int offset_sh; /* offset if short header is received */
switch (dir) {
case Q_DST:
offset_sh = 1; /* follows flags */
offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
break;
case Q_SRC:
offset_sh = 3; /* follows flags, dstnode */
offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
break;
case Q_AND:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(cstate, addr, Q_SRC);
b1 = gen_dnhostop(cstate, addr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(cstate, addr, Q_SRC);
b1 = gen_dnhostop(cstate, addr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ISO:
bpf_error(cstate, "ISO host filtering not implemented");
default:
abort();
}
b0 = gen_linktype(cstate, ETHERTYPE_DN);
/* Check for pad = 1, long header case */
tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
(bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh,
BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b1);
/* Check for pad = 0, long header case */
tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 1, short header case */
tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
(bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 0, short header case */
tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Combine with test for cstate->linktype */
gen_and(b0, b1);
return b1;
}
/*
* Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
* test the bottom-of-stack bit, and then check the version number
* field in the IP header.
*/
static struct block *
gen_mpls_linktype(compiler_state_t *cstate, int proto)
{
struct block *b0, *b1;
switch (proto) {
case Q_IP:
/* match the bottom-of-stack bit */
b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
/* match the IPv4 version number */
b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0);
gen_and(b0, b1);
return b1;
case Q_IPV6:
/* match the bottom-of-stack bit */
b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
/* match the IPv4 version number */
b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
gen_and(b0, b1);
return b1;
default:
abort();
}
}
static struct block *
gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
int proto, int dir, int type)
{
struct block *b0, *b1;
const char *typestr;
if (type == Q_NET)
typestr = "net";
else
typestr = "host";
switch (proto) {
case Q_DEFAULT:
b0 = gen_host(cstate, addr, mask, Q_IP, dir, type);
/*
* Only check for non-IPv4 addresses if we're not
* checking MPLS-encapsulated packets.
*/
if (cstate->label_stack_depth == 0) {
b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type);
gen_or(b0, b1);
b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type);
gen_or(b1, b0);
}
return b0;
case Q_IP:
return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16);
case Q_RARP:
return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
case Q_ARP:
return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24);
case Q_TCP:
bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
case Q_SCTP:
bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
case Q_UDP:
bpf_error(cstate, "'udp' modifier applied to %s", typestr);
case Q_ICMP:
bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
case Q_IGMP:
bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
case Q_IGRP:
bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
case Q_PIM:
bpf_error(cstate, "'pim' modifier applied to %s", typestr);
case Q_VRRP:
bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
case Q_CARP:
bpf_error(cstate, "'carp' modifier applied to %s", typestr);
case Q_ATALK:
bpf_error(cstate, "ATALK host filtering not implemented");
case Q_AARP:
bpf_error(cstate, "AARP host filtering not implemented");
case Q_DECNET:
return gen_dnhostop(cstate, addr, dir);
case Q_SCA:
bpf_error(cstate, "SCA host filtering not implemented");
case Q_LAT:
bpf_error(cstate, "LAT host filtering not implemented");
case Q_MOPDL:
bpf_error(cstate, "MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error(cstate, "MOPRC host filtering not implemented");
case Q_IPV6:
bpf_error(cstate, "'ip6' modifier applied to ip host");
case Q_ICMPV6:
bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
case Q_AH:
bpf_error(cstate, "'ah' modifier applied to %s", typestr);
case Q_ESP:
bpf_error(cstate, "'esp' modifier applied to %s", typestr);
case Q_ISO:
bpf_error(cstate, "ISO host filtering not implemented");
case Q_ESIS:
bpf_error(cstate, "'esis' modifier applied to %s", typestr);
case Q_ISIS:
bpf_error(cstate, "'isis' modifier applied to %s", typestr);
case Q_CLNP:
bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
case Q_STP:
bpf_error(cstate, "'stp' modifier applied to %s", typestr);
case Q_IPX:
bpf_error(cstate, "IPX host filtering not implemented");
case Q_NETBEUI:
bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
case Q_RADIO:
bpf_error(cstate, "'radio' modifier applied to %s", typestr);
default:
abort();
}
/* NOTREACHED */
}
#ifdef INET6
static struct block *
gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
struct in6_addr *mask, int proto, int dir, int type)
{
const char *typestr;
if (type == Q_NET)
typestr = "net";
else
typestr = "host";
switch (proto) {
case Q_DEFAULT:
return gen_host6(cstate, addr, mask, Q_IPV6, dir, type);
case Q_LINK:
bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr);
case Q_IP:
bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr);
case Q_RARP:
bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr);
case Q_ARP:
bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr);
case Q_SCTP:
bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
case Q_TCP:
bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
case Q_UDP:
bpf_error(cstate, "'udp' modifier applied to %s", typestr);
case Q_ICMP:
bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
case Q_IGMP:
bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
case Q_IGRP:
bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
case Q_PIM:
bpf_error(cstate, "'pim' modifier applied to %s", typestr);
case Q_VRRP:
bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
case Q_CARP:
bpf_error(cstate, "'carp' modifier applied to %s", typestr);
case Q_ATALK:
bpf_error(cstate, "ATALK host filtering not implemented");
case Q_AARP:
bpf_error(cstate, "AARP host filtering not implemented");
case Q_DECNET:
bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr);
case Q_SCA:
bpf_error(cstate, "SCA host filtering not implemented");
case Q_LAT:
bpf_error(cstate, "LAT host filtering not implemented");
case Q_MOPDL:
bpf_error(cstate, "MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error(cstate, "MOPRC host filtering not implemented");
case Q_IPV6:
return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
case Q_ICMPV6:
bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
case Q_AH:
bpf_error(cstate, "'ah' modifier applied to %s", typestr);
case Q_ESP:
bpf_error(cstate, "'esp' modifier applied to %s", typestr);
case Q_ISO:
bpf_error(cstate, "ISO host filtering not implemented");
case Q_ESIS:
bpf_error(cstate, "'esis' modifier applied to %s", typestr);
case Q_ISIS:
bpf_error(cstate, "'isis' modifier applied to %s", typestr);
case Q_CLNP:
bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
case Q_STP:
bpf_error(cstate, "'stp' modifier applied to %s", typestr);
case Q_IPX:
bpf_error(cstate, "IPX host filtering not implemented");
case Q_NETBEUI:
bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
case Q_RADIO:
bpf_error(cstate, "'radio' modifier applied to %s", typestr);
default:
abort();
}
/* NOTREACHED */
}
#endif
#ifndef INET6
static struct block *
gen_gateway(compiler_state_t *cstate, const u_char *eaddr,
struct addrinfo *alist, int proto, int dir)
{
struct block *b0, *b1, *tmp;
struct addrinfo *ai;
struct sockaddr_in *sin;
if (dir != 0)
bpf_error(cstate, "direction applied to 'gateway'");
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_ARP:
case Q_RARP:
switch (cstate->linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b1 = gen_prevlinkhdr_check(cstate);
b0 = gen_ehostop(cstate, eaddr, Q_OR);
if (b1 != NULL)
gen_and(b1, b0);
break;
case DLT_FDDI:
b0 = gen_fhostop(cstate, eaddr, Q_OR);
break;
case DLT_IEEE802:
b0 = gen_thostop(cstate, eaddr, Q_OR);
break;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
break;
case DLT_SUNATM:
/*
* This is LLC-multiplexed traffic; if it were
* LANE, cstate->linktype would have been set to
* DLT_EN10MB.
*/
bpf_error(cstate,
"'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
break;
case DLT_IP_OVER_FC:
b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
break;
default:
bpf_error(cstate,
"'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
}
b1 = NULL;
for (ai = alist; ai != NULL; ai = ai->ai_next) {
/*
* Does it have an address?
*/
if (ai->ai_addr != NULL) {
/*
* Yes. Is it an IPv4 address?
*/
if (ai->ai_addr->sa_family == AF_INET) {
/*
* Generate an entry for it.
*/
sin = (struct sockaddr_in *)ai->ai_addr;
tmp = gen_host(cstate,
ntohl(sin->sin_addr.s_addr),
0xffffffff, proto, Q_OR, Q_HOST);
/*
* Is it the *first* IPv4 address?
*/
if (b1 == NULL) {
/*
* Yes, so start with it.
*/
b1 = tmp;
} else {
/*
* No, so OR it into the
* existing set of
* addresses.
*/
gen_or(b1, tmp);
b1 = tmp;
}
}
}
}
if (b1 == NULL) {
/*
* No IPv4 addresses found.
*/
return (NULL);
}
gen_not(b1);
gen_and(b0, b1);
return b1;
}
bpf_error(cstate, "illegal modifier of 'gateway'");
/* NOTREACHED */
}
#endif
struct block *
gen_proto_abbrev(compiler_state_t *cstate, int proto)
{
struct block *b0;
struct block *b1;
switch (proto) {
case Q_SCTP:
b1 = gen_proto(cstate, IPPROTO_SCTP, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_TCP:
b1 = gen_proto(cstate, IPPROTO_TCP, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_UDP:
b1 = gen_proto(cstate, IPPROTO_UDP, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ICMP:
b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGMP
#define IPPROTO_IGMP 2
#endif
case Q_IGMP:
b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGRP
#define IPPROTO_IGRP 9
#endif
case Q_IGRP:
b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_PIM
#define IPPROTO_PIM 103
#endif
case Q_PIM:
b1 = gen_proto(cstate, IPPROTO_PIM, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
#ifndef IPPROTO_VRRP
#define IPPROTO_VRRP 112
#endif
case Q_VRRP:
b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_CARP
#define IPPROTO_CARP 112
#endif
case Q_CARP:
b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT);
break;
case Q_IP:
b1 = gen_linktype(cstate, ETHERTYPE_IP);
break;
case Q_ARP:
b1 = gen_linktype(cstate, ETHERTYPE_ARP);
break;
case Q_RARP:
b1 = gen_linktype(cstate, ETHERTYPE_REVARP);
break;
case Q_LINK:
bpf_error(cstate, "link layer applied in wrong context");
case Q_ATALK:
b1 = gen_linktype(cstate, ETHERTYPE_ATALK);
break;
case Q_AARP:
b1 = gen_linktype(cstate, ETHERTYPE_AARP);
break;
case Q_DECNET:
b1 = gen_linktype(cstate, ETHERTYPE_DN);
break;
case Q_SCA:
b1 = gen_linktype(cstate, ETHERTYPE_SCA);
break;
case Q_LAT:
b1 = gen_linktype(cstate, ETHERTYPE_LAT);
break;
case Q_MOPDL:
b1 = gen_linktype(cstate, ETHERTYPE_MOPDL);
break;
case Q_MOPRC:
b1 = gen_linktype(cstate, ETHERTYPE_MOPRC);
break;
case Q_IPV6:
b1 = gen_linktype(cstate, ETHERTYPE_IPV6);
break;
#ifndef IPPROTO_ICMPV6
#define IPPROTO_ICMPV6 58
#endif
case Q_ICMPV6:
b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
break;
#ifndef IPPROTO_AH
#define IPPROTO_AH 51
#endif
case Q_AH:
b1 = gen_proto(cstate, IPPROTO_AH, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_AH, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
#ifndef IPPROTO_ESP
#define IPPROTO_ESP 50
#endif
case Q_ESP:
b1 = gen_proto(cstate, IPPROTO_ESP, Q_IP, Q_DEFAULT);
b0 = gen_proto(cstate, IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISO:
b1 = gen_linktype(cstate, LLCSAP_ISONS);
break;
case Q_ESIS:
b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT);
break;
case Q_ISIS:
b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
break;
case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_LSP:
b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_SNP:
b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_CSNP:
b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_PSNP:
b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_CLNP:
b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT);
break;
case Q_STP:
b1 = gen_linktype(cstate, LLCSAP_8021D);
break;
case Q_IPX:
b1 = gen_linktype(cstate, LLCSAP_IPX);
break;
case Q_NETBEUI:
b1 = gen_linktype(cstate, LLCSAP_NETBEUI);
break;
case Q_RADIO:
bpf_error(cstate, "'radio' is not a valid protocol type");
default:
abort();
}
return b1;
}
static struct block *
gen_ipfrag(compiler_state_t *cstate)
{
struct slist *s;
struct block *b;
/* not IPv4 frag other than the first frag */
s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H);
b = new_block(cstate, JMP(BPF_JSET));
b->s.k = 0x1fff;
b->stmts = s;
gen_not(b);
return b;
}
/*
* Generate a comparison to a port value in the transport-layer header
* at the specified offset from the beginning of that header.
*
* XXX - this handles a variable-length prefix preceding the link-layer
* header, such as the radiotap or AVS radio prefix, but doesn't handle
* variable-length link-layer headers (such as Token Ring or 802.11
* headers).
*/
static struct block *
gen_portatom(compiler_state_t *cstate, int off, bpf_int32 v)
{
return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
}
static struct block *
gen_portatom6(compiler_state_t *cstate, int off, bpf_int32 v)
{
return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
}
struct block *
gen_portop(compiler_state_t *cstate, int port, int proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' and not a fragment other than the first fragment */
tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag(cstate);
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portatom(cstate, 0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom(cstate, 2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom(cstate, 0, (bpf_int32)port);
b1 = gen_portatom(cstate, 2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom(cstate, 0, (bpf_int32)port);
b1 = gen_portatom(cstate, 2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port(compiler_state_t *cstate, int port, int ip_proto, int dir)
{
struct block *b0, *b1, *tmp;
/*
* ether proto ip
*
* For FDDI, RFC 1188 says that SNAP encapsulation is used,
* not LLC encapsulation with LLCSAP_IP.
*
* For IEEE 802 networks - which includes 802.5 token ring
* (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
* says that SNAP encapsulation is used, not LLC encapsulation
* with LLCSAP_IP.
*
* For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
* RFC 2225 say that SNAP encapsulation is used, not LLC
* encapsulation with LLCSAP_IP.
*
* So we always check for ETHERTYPE_IP.
*/
b0 = gen_linktype(cstate, ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portop(cstate, port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
struct block *
gen_portop6(compiler_state_t *cstate, int port, int proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ip6 proto 'proto' */
/* XXX - catch the first fragment of a fragmented packet? */
b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portatom6(cstate, 0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port6(compiler_state_t *cstate, int port, int ip_proto, int dir)
{
struct block *b0, *b1, *tmp;
/* link proto ip6 */
b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portop6(cstate, port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
/* gen_portrange code */
static struct block *
gen_portrangeatom(compiler_state_t *cstate, int off, bpf_int32 v1,
bpf_int32 v2)
{
struct block *b1, *b2;
if (v1 > v2) {
/*
* Reverse the order of the ports, so v1 is the lower one.
*/
bpf_int32 vtemp;
vtemp = v1;
v1 = v2;
v2 = vtemp;
}
b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1);
b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2);
gen_and(b1, b2);
return b2;
}
struct block *
gen_portrangeop(compiler_state_t *cstate, int port1, int port2, int proto,
int dir)
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' and not a fragment other than the first fragment */
tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag(cstate);
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_DST:
b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrange(compiler_state_t *cstate, int port1, int port2, int ip_proto,
int dir)
{
struct block *b0, *b1, *tmp;
/* link proto ip */
b0 = gen_linktype(cstate, ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portrangeop(cstate, port1, port2, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrangeatom6(compiler_state_t *cstate, int off, bpf_int32 v1,
bpf_int32 v2)
{
struct block *b1, *b2;
if (v1 > v2) {
/*
* Reverse the order of the ports, so v1 is the lower one.
*/
bpf_int32 vtemp;
vtemp = v1;
v1 = v2;
v2 = vtemp;
}
b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1);
b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2);
gen_and(b1, b2);
return b2;
}
struct block *
gen_portrangeop6(compiler_state_t *cstate, int port1, int port2, int proto,
int dir)
{
struct block *b0, *b1, *tmp;
/* ip6 proto 'proto' */
/* XXX - catch the first fragment of a fragmented packet? */
b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_DST:
b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrange6(compiler_state_t *cstate, int port1, int port2, int ip_proto,
int dir)
{
struct block *b0, *b1, *tmp;
/* link proto ip6 */
b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portrangeop6(cstate, port1, port2, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static int
lookup_proto(compiler_state_t *cstate, const char *name, int proto)
{
register int v;
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_IPV6:
v = pcap_nametoproto(name);
if (v == PROTO_UNDEF)
bpf_error(cstate, "unknown ip proto '%s'", name);
break;
case Q_LINK:
/* XXX should look up h/w protocol type based on cstate->linktype */
v = pcap_nametoeproto(name);
if (v == PROTO_UNDEF) {
v = pcap_nametollc(name);
if (v == PROTO_UNDEF)
bpf_error(cstate, "unknown ether proto '%s'", name);
}
break;
case Q_ISO:
if (strcmp(name, "esis") == 0)
v = ISO9542_ESIS;
else if (strcmp(name, "isis") == 0)
v = ISO10589_ISIS;
else if (strcmp(name, "clnp") == 0)
v = ISO8473_CLNP;
else
bpf_error(cstate, "unknown osi proto '%s'", name);
break;
default:
v = PROTO_UNDEF;
break;
}
return v;
}
#if 0
struct stmt *
gen_joinsp(struct stmt **s, int n)
{
return NULL;
}
#endif
static struct block *
gen_protochain(compiler_state_t *cstate, int v, int proto, int dir)
{
#ifdef NO_PROTOCHAIN
return gen_proto(cstate, v, proto, dir);
#else
struct block *b0, *b;
struct slist *s[100];
int fix2, fix3, fix4, fix5;
int ahcheck, again, end;
int i, max;
int reg2 = alloc_reg(cstate);
memset(s, 0, sizeof(s));
fix3 = fix4 = fix5 = 0;
switch (proto) {
case Q_IP:
case Q_IPV6:
break;
case Q_DEFAULT:
b0 = gen_protochain(cstate, v, Q_IP, dir);
b = gen_protochain(cstate, v, Q_IPV6, dir);
gen_or(b0, b);
return b;
default:
bpf_error(cstate, "bad protocol applied for 'protochain'");
/*NOTREACHED*/
}
/*
* We don't handle variable-length prefixes before the link-layer
* header, or variable-length link-layer headers, here yet.
* We might want to add BPF instructions to do the protochain
* work, to simplify that and, on platforms that have a BPF
* interpreter with the new instructions, let the filtering
* be done in the kernel. (We already require a modified BPF
* engine to do the protochain stuff, to support backward
* branches, and backward branch support is unlikely to appear
* in kernel BPF engines.)
*/
if (cstate->off_linkpl.is_variable)
bpf_error(cstate, "'protochain' not supported with variable length headers");
cstate->no_optimize = 1; /* this code is not compatible with optimizer yet */
/*
* s[0] is a dummy entry to protect other BPF insn from damage
* by s[fix] = foo with uninitialized variable "fix". It is somewhat
* hard to find interdependency made by jump table fixup.
*/
i = 0;
s[i] = new_stmt(cstate, 0); /*dummy*/
i++;
switch (proto) {
case Q_IP:
b0 = gen_linktype(cstate, ETHERTYPE_IP);
/* A = ip->ip_p */
s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9;
i++;
/* X = ip->ip_hl << 2 */
s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
i++;
break;
case Q_IPV6:
b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
/* A = ip6->ip_nxt */
s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6;
i++;
/* X = sizeof(struct ip6_hdr) */
s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM);
s[i]->s.k = 40;
i++;
break;
default:
bpf_error(cstate, "unsupported proto to gen_protochain");
/*NOTREACHED*/
}
/* again: if (A == v) goto end; else fall through; */
again = i;
s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.k = v;
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
fix5 = i;
i++;
#ifndef IPPROTO_NONE
#define IPPROTO_NONE 59
#endif
/* if (A == IPPROTO_NONE) goto end */
s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_NONE;
s[fix5]->s.jf = s[i];
fix2 = i;
i++;
if (proto == Q_IPV6) {
int v6start, v6end, v6advance, j;
v6start = i;
/* if (A == IPPROTO_HOPOPTS) goto v6advance */
s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_HOPOPTS;
s[fix2]->s.jf = s[i];
i++;
/* if (A == IPPROTO_DSTOPTS) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_DSTOPTS;
i++;
/* if (A == IPPROTO_ROUTING) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_ROUTING;
i++;
/* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_FRAGMENT;
fix3 = i;
v6end = i;
i++;
/* v6advance: */
v6advance = i;
/*
* in short,
* A = P[X + packet head];
* X = X + (P[X + packet head + 1] + 1) * 8;
*/
/* A = P[X + packet head] */
s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(cstate, BPF_ST);
s[i]->s.k = reg2;
i++;
/* A = P[X + packet head + 1]; */
s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1;
i++;
/* A += 1 */
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* A *= 8 */
s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 8;
i++;
/* A += X */
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
s[i]->s.k = 0;
i++;
/* X = A; */
s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
s[i - 1]->s.jf = s[i];
i++;
/* fixup */
for (j = v6start; j <= v6end; j++)
s[j]->s.jt = s[v6advance];
} else {
/* nop */
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jf = s[i];
i++;
}
/* ahcheck: */
ahcheck = i;
/* if (A == IPPROTO_AH) then fall through; else goto end; */
s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_AH;
if (fix3)
s[fix3]->s.jf = s[ahcheck];
fix4 = i;
i++;
/*
* in short,
* A = P[X];
* X = X + (P[X + 1] + 2) * 4;
*/
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(cstate, BPF_ST);
s[i]->s.k = reg2;
i++;
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
i++;
/* A += 1 */
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
i++;
/* A += 2 */
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 2;
i++;
/* A *= 4 */
s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 4;
i++;
/* X = A; */
s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
i++;
/* end: nop */
end = i;
s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jt = s[end];
s[fix4]->s.jf = s[end];
s[fix5]->s.jt = s[end];
i++;
/*
* make slist chain
*/
max = i;
for (i = 0; i < max - 1; i++)
s[i]->next = s[i + 1];
s[max - 1]->next = NULL;
/*
* emit final check
*/
b = new_block(cstate, JMP(BPF_JEQ));
b->stmts = s[1]; /*remember, s[0] is dummy*/
b->s.k = v;
free_reg(cstate, reg2);
gen_and(b0, b);
return b;
#endif
}
static struct block *
gen_check_802_11_data_frame(compiler_state_t *cstate)
{
struct slist *s;
struct block *b0, *b1;
/*
* A data frame has the 0x08 bit (b3) in the frame control field set
* and the 0x04 bit (b2) clear.
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b0 = new_block(cstate, JMP(BPF_JSET));
b0->s.k = 0x08;
b0->stmts = s;
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
gen_and(b1, b0);
return b0;
}
/*
* Generate code that checks whether the packet is a packet for protocol
* <proto> and whether the type field in that protocol's header has
* the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
* IP packet and checks the protocol number in the IP header against <v>.
*
* If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
* against Q_IP and Q_IPV6.
*/
static struct block *
gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
{
struct block *b0, *b1;
#ifndef CHASE_CHAIN
struct block *b2;
#endif
if (dir != Q_DEFAULT)
bpf_error(cstate, "direction applied to 'proto'");
switch (proto) {
case Q_DEFAULT:
b0 = gen_proto(cstate, v, Q_IP, dir);
b1 = gen_proto(cstate, v, Q_IPV6, dir);
gen_or(b0, b1);
return b1;
case Q_IP:
/*
* For FDDI, RFC 1188 says that SNAP encapsulation is used,
* not LLC encapsulation with LLCSAP_IP.
*
* For IEEE 802 networks - which includes 802.5 token ring
* (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
* says that SNAP encapsulation is used, not LLC encapsulation
* with LLCSAP_IP.
*
* For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
* RFC 2225 say that SNAP encapsulation is used, not LLC
* encapsulation with LLCSAP_IP.
*
* So we always check for ETHERTYPE_IP.
*/
b0 = gen_linktype(cstate, ETHERTYPE_IP);
#ifndef CHASE_CHAIN
b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(cstate, v, Q_IP);
#endif
gen_and(b0, b1);
return b1;
case Q_ISO:
switch (cstate->linktype) {
case DLT_FRELAY:
/*
* Frame Relay packets typically have an OSI
* NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)"
* generates code to check for all the OSI
* NLPIDs, so calling it and then adding a check
* for the particular NLPID for which we're
* looking is bogus, as we can just check for
* the NLPID.
*
* What we check for is the NLPID and a frame
* control field value of UI, i.e. 0x03 followed
* by the NLPID.
*
* XXX - assumes a 2-byte Frame Relay header with
* DLCI and flags. What if the address is longer?
*
* XXX - what about SNAP-encapsulated frames?
*/
return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v);
/*NOTREACHED*/
break;
case DLT_C_HDLC:
/*
* Cisco uses an Ethertype lookalike - for OSI,
* it's 0xfefe.
*/
b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
/* OSI in C-HDLC is stuffed with a fudge byte */
b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
default:
b0 = gen_linktype(cstate, LLCSAP_ISONS);
b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
}
case Q_ISIS:
b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
/*
* 4 is the offset of the PDU type relative to the IS-IS
* header.
*/
b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
case Q_ARP:
bpf_error(cstate, "arp does not encapsulate another protocol");
/* NOTREACHED */
case Q_RARP:
bpf_error(cstate, "rarp does not encapsulate another protocol");
/* NOTREACHED */
case Q_ATALK:
bpf_error(cstate, "atalk encapsulation is not specifiable");
/* NOTREACHED */
case Q_DECNET:
bpf_error(cstate, "decnet encapsulation is not specifiable");
/* NOTREACHED */
case Q_SCA:
bpf_error(cstate, "sca does not encapsulate another protocol");
/* NOTREACHED */
case Q_LAT:
bpf_error(cstate, "lat does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPRC:
bpf_error(cstate, "moprc does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPDL:
bpf_error(cstate, "mopdl does not encapsulate another protocol");
/* NOTREACHED */
case Q_LINK:
return gen_linktype(cstate, v);
case Q_UDP:
bpf_error(cstate, "'udp proto' is bogus");
/* NOTREACHED */
case Q_TCP:
bpf_error(cstate, "'tcp proto' is bogus");
/* NOTREACHED */
case Q_SCTP:
bpf_error(cstate, "'sctp proto' is bogus");
/* NOTREACHED */
case Q_ICMP:
bpf_error(cstate, "'icmp proto' is bogus");
/* NOTREACHED */
case Q_IGMP:
bpf_error(cstate, "'igmp proto' is bogus");
/* NOTREACHED */
case Q_IGRP:
bpf_error(cstate, "'igrp proto' is bogus");
/* NOTREACHED */
case Q_PIM:
bpf_error(cstate, "'pim proto' is bogus");
/* NOTREACHED */
case Q_VRRP:
bpf_error(cstate, "'vrrp proto' is bogus");
/* NOTREACHED */
case Q_CARP:
bpf_error(cstate, "'carp proto' is bogus");
/* NOTREACHED */
case Q_IPV6:
b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
#ifndef CHASE_CHAIN
/*
* Also check for a fragment header before the final
* header.
*/
b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, (bpf_int32)v);
gen_and(b2, b1);
b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)v);
gen_or(b2, b1);
#else
b1 = gen_protochain(cstate, v, Q_IPV6);
#endif
gen_and(b0, b1);
return b1;
case Q_ICMPV6:
bpf_error(cstate, "'icmp6 proto' is bogus");
case Q_AH:
bpf_error(cstate, "'ah proto' is bogus");
case Q_ESP:
bpf_error(cstate, "'ah proto' is bogus");
case Q_STP:
bpf_error(cstate, "'stp proto' is bogus");
case Q_IPX:
bpf_error(cstate, "'ipx proto' is bogus");
case Q_NETBEUI:
bpf_error(cstate, "'netbeui proto' is bogus");
case Q_RADIO:
bpf_error(cstate, "'radio proto' is bogus");
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
struct block *
gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
{
int proto = q.proto;
int dir = q.dir;
int tproto;
u_char *eaddr;
bpf_u_int32 mask, addr;
struct addrinfo *res, *res0;
struct sockaddr_in *sin4;
#ifdef INET6
int tproto6;
struct sockaddr_in6 *sin6;
struct in6_addr mask128;
#endif /*INET6*/
struct block *b, *tmp;
int port, real_proto;
int port1, port2;
switch (q.addr) {
case Q_NET:
addr = pcap_nametonetaddr(name);
if (addr == 0)
bpf_error(cstate, "unknown network '%s'", name);
/* Left justify network addr and calculate its network mask */
mask = 0xffffffff;
while (addr && (addr & 0xff000000) == 0) {
addr <<= 8;
mask <<= 8;
}
return gen_host(cstate, addr, mask, proto, dir, q.addr);
case Q_DEFAULT:
case Q_HOST:
if (proto == Q_LINK) {
switch (cstate->linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate,
"unknown ether host '%s'", name);
tmp = gen_prevlinkhdr_check(cstate);
b = gen_ehostop(cstate, eaddr, dir);
if (tmp != NULL)
gen_and(tmp, b);
free(eaddr);
return b;
case DLT_FDDI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate,
"unknown FDDI host '%s'", name);
b = gen_fhostop(cstate, eaddr, dir);
free(eaddr);
return b;
case DLT_IEEE802:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate,
"unknown token ring host '%s'", name);
b = gen_thostop(cstate, eaddr, dir);
free(eaddr);
return b;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate,
"unknown 802.11 host '%s'", name);
b = gen_wlanhostop(cstate, eaddr, dir);
free(eaddr);
return b;
case DLT_IP_OVER_FC:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate,
"unknown Fibre Channel host '%s'", name);
b = gen_ipfchostop(cstate, eaddr, dir);
free(eaddr);
return b;
}
bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
} else if (proto == Q_DECNET) {
unsigned short dn_addr;
if (!__pcap_nametodnaddr(name, &dn_addr)) {
#ifdef DECNETLIB
bpf_error(cstate, "unknown decnet host name '%s'\n", name);
#else
bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n",
name);
#endif
}
/*
* I don't think DECNET hosts can be multihomed, so
* there is no need to build up a list of addresses
*/
return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr));
} else {
#ifdef INET6
memset(&mask128, 0xff, sizeof(mask128));
#endif
res0 = res = pcap_nametoaddrinfo(name);
if (res == NULL)
bpf_error(cstate, "unknown host '%s'", name);
cstate->ai = res;
b = tmp = NULL;
tproto = proto;
#ifdef INET6
tproto6 = proto;
#endif
if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
tproto == Q_DEFAULT) {
tproto = Q_IP;
#ifdef INET6
tproto6 = Q_IPV6;
#endif
}
for (res = res0; res; res = res->ai_next) {
switch (res->ai_family) {
case AF_INET:
#ifdef INET6
if (tproto == Q_IPV6)
continue;
#endif
sin4 = (struct sockaddr_in *)
res->ai_addr;
tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
0xffffffff, tproto, dir, q.addr);
break;
#ifdef INET6
case AF_INET6:
if (tproto6 == Q_IP)
continue;
sin6 = (struct sockaddr_in6 *)
res->ai_addr;
tmp = gen_host6(cstate, &sin6->sin6_addr,
&mask128, tproto6, dir, q.addr);
break;
#endif
default:
continue;
}
if (b)
gen_or(b, tmp);
b = tmp;
}
cstate->ai = NULL;
freeaddrinfo(res0);
if (b == NULL) {
bpf_error(cstate, "unknown host '%s'%s", name,
(proto == Q_DEFAULT)
? ""
: " for specified address family");
}
return b;
}
case Q_PORT:
if (proto != Q_DEFAULT &&
proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
bpf_error(cstate, "illegal qualifier of 'port'");
if (pcap_nametoport(name, &port, &real_proto) == 0)
bpf_error(cstate, "unknown port '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error(cstate, "port '%s' is tcp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error(cstate, "port '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error(cstate, "port '%s' is udp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error(cstate, "port '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
if (proto == Q_SCTP) {
if (real_proto == IPPROTO_UDP)
bpf_error(cstate, "port '%s' is udp", name);
else if (real_proto == IPPROTO_TCP)
bpf_error(cstate, "port '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_SCTP;
}
if (port < 0)
bpf_error(cstate, "illegal port number %d < 0", port);
if (port > 65535)
bpf_error(cstate, "illegal port number %d > 65535", port);
b = gen_port(cstate, port, real_proto, dir);
gen_or(gen_port6(cstate, port, real_proto, dir), b);
return b;
case Q_PORTRANGE:
if (proto != Q_DEFAULT &&
proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
bpf_error(cstate, "illegal qualifier of 'portrange'");
if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
bpf_error(cstate, "unknown port in range '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error(cstate, "port in range '%s' is tcp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error(cstate, "port in range '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error(cstate, "port in range '%s' is udp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error(cstate, "port in range '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
if (proto == Q_SCTP) {
if (real_proto == IPPROTO_UDP)
bpf_error(cstate, "port in range '%s' is udp", name);
else if (real_proto == IPPROTO_TCP)
bpf_error(cstate, "port in range '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_SCTP;
}
if (port1 < 0)
bpf_error(cstate, "illegal port number %d < 0", port1);
if (port1 > 65535)
bpf_error(cstate, "illegal port number %d > 65535", port1);
if (port2 < 0)
bpf_error(cstate, "illegal port number %d < 0", port2);
if (port2 > 65535)
bpf_error(cstate, "illegal port number %d > 65535", port2);
b = gen_portrange(cstate, port1, port2, real_proto, dir);
gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
return b;
case Q_GATEWAY:
#ifndef INET6
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(cstate, "unknown ether host: %s", name);
res = pcap_nametoaddrinfo(name);
cstate->ai = res;
if (res == NULL)
bpf_error(cstate, "unknown host '%s'", name);
b = gen_gateway(cstate, eaddr, res, proto, dir);
cstate->ai = NULL;
freeaddrinfo(res);
if (b == NULL)
bpf_error(cstate, "unknown host '%s'", name);
return b;
#else
bpf_error(cstate, "'gateway' not supported in this configuration");
#endif /*INET6*/
case Q_PROTO:
real_proto = lookup_proto(cstate, name, proto);
if (real_proto >= 0)
return gen_proto(cstate, real_proto, proto, dir);
else
bpf_error(cstate, "unknown protocol: %s", name);
case Q_PROTOCHAIN:
real_proto = lookup_proto(cstate, name, proto);
if (real_proto >= 0)
return gen_protochain(cstate, real_proto, proto, dir);
else
bpf_error(cstate, "unknown protocol: %s", name);
case Q_UNDEF:
syntax(cstate);
/* NOTREACHED */
}
abort();
/* NOTREACHED */
}
struct block *
gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
unsigned int masklen, struct qual q)
{
register int nlen, mlen;
bpf_u_int32 n, m;
nlen = __pcap_atoin(s1, &n);
/* Promote short ipaddr */
n <<= 32 - nlen;
if (s2 != NULL) {
mlen = __pcap_atoin(s2, &m);
/* Promote short ipaddr */
m <<= 32 - mlen;
if ((n & ~m) != 0)
bpf_error(cstate, "non-network bits set in \"%s mask %s\"",
s1, s2);
} else {
/* Convert mask len to mask */
if (masklen > 32)
bpf_error(cstate, "mask length must be <= 32");
if (masklen == 0) {
/*
* X << 32 is not guaranteed by C to be 0; it's
* undefined.
*/
m = 0;
} else
m = 0xffffffff << (32 - masklen);
if ((n & ~m) != 0)
bpf_error(cstate, "non-network bits set in \"%s/%d\"",
s1, masklen);
}
switch (q.addr) {
case Q_NET:
return gen_host(cstate, n, m, q.proto, q.dir, q.addr);
default:
bpf_error(cstate, "Mask syntax for networks only");
/* NOTREACHED */
}
/* NOTREACHED */
}
struct block *
gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
{
bpf_u_int32 mask;
int proto = q.proto;
int dir = q.dir;
register int vlen;
if (s == NULL)
vlen = 32;
else if (q.proto == Q_DECNET) {
vlen = __pcap_atodn(s, &v);
if (vlen == 0)
bpf_error(cstate, "malformed decnet address '%s'", s);
} else
vlen = __pcap_atoin(s, &v);
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
case Q_NET:
if (proto == Q_DECNET)
return gen_host(cstate, v, 0, proto, dir, q.addr);
else if (proto == Q_LINK) {
bpf_error(cstate, "illegal link layer address");
} else {
mask = 0xffffffff;
if (s == NULL && q.addr == Q_NET) {
/* Promote short net number */
while (v && (v & 0xff000000) == 0) {
v <<= 8;
mask <<= 8;
}
} else {
/* Promote short ipaddr */
v <<= 32 - vlen;
mask <<= 32 - vlen ;
}
return gen_host(cstate, v, mask, proto, dir, q.addr);
}
case Q_PORT:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_SCTP)
proto = IPPROTO_SCTP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error(cstate, "illegal qualifier of 'port'");
if (v > 65535)
bpf_error(cstate, "illegal port number %u > 65535", v);
{
struct block *b;
b = gen_port(cstate, (int)v, proto, dir);
gen_or(gen_port6(cstate, (int)v, proto, dir), b);
return b;
}
case Q_PORTRANGE:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_SCTP)
proto = IPPROTO_SCTP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error(cstate, "illegal qualifier of 'portrange'");
if (v > 65535)
bpf_error(cstate, "illegal port number %u > 65535", v);
{
struct block *b;
b = gen_portrange(cstate, (int)v, (int)v, proto, dir);
gen_or(gen_portrange6(cstate, (int)v, (int)v, proto, dir), b);
return b;
}
case Q_GATEWAY:
bpf_error(cstate, "'gateway' requires a name");
/* NOTREACHED */
case Q_PROTO:
return gen_proto(cstate, (int)v, proto, dir);
case Q_PROTOCHAIN:
return gen_protochain(cstate, (int)v, proto, dir);
case Q_UNDEF:
syntax(cstate);
/* NOTREACHED */
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
#ifdef INET6
struct block *
gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
unsigned int masklen, struct qual q)
{
struct addrinfo *res;
struct in6_addr *addr;
struct in6_addr mask;
struct block *b;
uint32_t *a, *m;
if (s2)
bpf_error(cstate, "no mask %s supported", s2);
res = pcap_nametoaddrinfo(s1);
if (!res)
bpf_error(cstate, "invalid ip6 address %s", s1);
cstate->ai = res;
if (res->ai_next)
bpf_error(cstate, "%s resolved to multiple address", s1);
addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
if (sizeof(mask) * 8 < masklen)
bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
memset(&mask, 0, sizeof(mask));
memset(&mask, 0xff, masklen / 8);
if (masklen % 8) {
mask.s6_addr[masklen / 8] =
(0xff << (8 - masklen % 8)) & 0xff;
}
a = (uint32_t *)addr;
m = (uint32_t *)&mask;
if ((a[0] & ~m[0]) || (a[1] & ~m[1])
|| (a[2] & ~m[2]) || (a[3] & ~m[3])) {
bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
}
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
if (masklen != 128)
bpf_error(cstate, "Mask syntax for networks only");
/* FALLTHROUGH */
case Q_NET:
b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
cstate->ai = NULL;
freeaddrinfo(res);
return b;
default:
bpf_error(cstate, "invalid qualifier against IPv6 address");
/* NOTREACHED */
}
}
#endif /*INET6*/
struct block *
gen_ecode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
{
struct block *b, *tmp;
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
switch (cstate->linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
tmp = gen_prevlinkhdr_check(cstate);
b = gen_ehostop(cstate, eaddr, (int)q.dir);
if (tmp != NULL)
gen_and(tmp, b);
return b;
case DLT_FDDI:
return gen_fhostop(cstate, eaddr, (int)q.dir);
case DLT_IEEE802:
return gen_thostop(cstate, eaddr, (int)q.dir);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
return gen_wlanhostop(cstate, eaddr, (int)q.dir);
case DLT_IP_OVER_FC:
return gen_ipfchostop(cstate, eaddr, (int)q.dir);
default:
bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
break;
}
}
bpf_error(cstate, "ethernet address used in non-ether expression");
/* NOTREACHED */
}
void
sappend(struct slist *s0, struct slist *s1)
{
/*
* This is definitely not the best way to do this, but the
* lists will rarely get long.
*/
while (s0->next)
s0 = s0->next;
s0->next = s1;
}
static struct slist *
xfer_to_x(compiler_state_t *cstate, struct arth *a)
{
struct slist *s;
s = new_stmt(cstate, BPF_LDX|BPF_MEM);
s->s.k = a->regno;
return s;
}
static struct slist *
xfer_to_a(compiler_state_t *cstate, struct arth *a)
{
struct slist *s;
s = new_stmt(cstate, BPF_LD|BPF_MEM);
s->s.k = a->regno;
return s;
}
/*
* Modify "index" to use the value stored into its register as an
* offset relative to the beginning of the header for the protocol
* "proto", and allocate a register and put an item "size" bytes long
* (1, 2, or 4) at that offset into that register, making it the register
* for "index".
*/
struct arth *
gen_load(compiler_state_t *cstate, int proto, struct arth *inst, int size)
{
struct slist *s, *tmp;
struct block *b;
int regno = alloc_reg(cstate);
free_reg(cstate, inst->regno);
switch (size) {
default:
bpf_error(cstate, "data size must be 1, 2, or 4");
case 1:
size = BPF_B;
break;
case 2:
size = BPF_H;
break;
case 4:
size = BPF_W;
break;
}
switch (proto) {
default:
bpf_error(cstate, "unsupported index operation");
case Q_RADIO:
/*
* The offset is relative to the beginning of the packet
* data, if we have a radio header. (If we don't, this
* is an error.)
*/
if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS &&
cstate->linktype != DLT_IEEE802_11_RADIO &&
cstate->linktype != DLT_PRISM_HEADER)
bpf_error(cstate, "radio information not present in capture");
/*
* Load into the X register the offset computed into the
* register specified by "index".
*/
s = xfer_to_x(cstate, inst);
/*
* Load the item at that offset.
*/
tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
sappend(s, tmp);
sappend(inst->s, s);
break;
case Q_LINK:
/*
* The offset is relative to the beginning of
* the link-layer header.
*
* XXX - what about ATM LANE? Should the index be
* relative to the beginning of the AAL5 frame, so
* that 0 refers to the beginning of the LE Control
* field, or relative to the beginning of the LAN
* frame, so that 0 refers, for Ethernet LANE, to
* the beginning of the destination address?
*/
s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr);
/*
* If "s" is non-null, it has code to arrange that the
* X register contains the length of the prefix preceding
* the link-layer header. Add to it the offset computed
* into the register specified by "index", and move that
* into the X register. Otherwise, just load into the X
* register the offset computed into the register specified
* by "index".
*/
if (s != NULL) {
sappend(s, xfer_to_a(cstate, inst));
sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
} else
s = xfer_to_x(cstate, inst);
/*
* Load the item at the sum of the offset we've put in the
* X register and the offset of the start of the link
* layer header (which is 0 if the radio header is
* variable-length; that header length is what we put
* into the X register and then added to the index).
*/
tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
tmp->s.k = cstate->off_linkhdr.constant_part;
sappend(s, tmp);
sappend(inst->s, s);
break;
case Q_IP:
case Q_ARP:
case Q_RARP:
case Q_ATALK:
case Q_DECNET:
case Q_SCA:
case Q_LAT:
case Q_MOPRC:
case Q_MOPDL:
case Q_IPV6:
/*
* The offset is relative to the beginning of
* the network-layer header.
* XXX - are there any cases where we want
* cstate->off_nl_nosnap?
*/
s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
/*
* If "s" is non-null, it has code to arrange that the
* X register contains the variable part of the offset
* of the link-layer payload. Add to it the offset
* computed into the register specified by "index",
* and move that into the X register. Otherwise, just
* load into the X register the offset computed into
* the register specified by "index".
*/
if (s != NULL) {
sappend(s, xfer_to_a(cstate, inst));
sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
} else
s = xfer_to_x(cstate, inst);
/*
* Load the item at the sum of the offset we've put in the
* X register, the offset of the start of the network
* layer header from the beginning of the link-layer
* payload, and the constant part of the offset of the
* start of the link-layer payload.
*/
tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
sappend(s, tmp);
sappend(inst->s, s);
/*
* Do the computation only if the packet contains
* the protocol in question.
*/
b = gen_proto_abbrev(cstate, proto);
if (inst->b)
gen_and(inst->b, b);
inst->b = b;
break;
case Q_SCTP:
case Q_TCP:
case Q_UDP:
case Q_ICMP:
case Q_IGMP:
case Q_IGRP:
case Q_PIM:
case Q_VRRP:
case Q_CARP:
/*
* The offset is relative to the beginning of
* the transport-layer header.
*
* Load the X register with the length of the IPv4 header
* (plus the offset of the link-layer header, if it's
* a variable-length header), in bytes.
*
* XXX - are there any cases where we want
* cstate->off_nl_nosnap?
* XXX - we should, if we're built with
* IPv6 support, generate code to load either
* IPv4, IPv6, or both, as appropriate.
*/
s = gen_loadx_iphdrlen(cstate);
/*
* The X register now contains the sum of the variable
* part of the offset of the link-layer payload and the
* length of the network-layer header.
*
* Load into the A register the offset relative to
* the beginning of the transport layer header,
* add the X register to that, move that to the
* X register, and load with an offset from the
* X register equal to the sum of the constant part of
* the offset of the link-layer payload and the offset,
* relative to the beginning of the link-layer payload,
* of the network-layer header.
*/
sappend(s, xfer_to_a(cstate, inst));
sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size));
tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
sappend(inst->s, s);
/*
* Do the computation only if the packet contains
* the protocol in question - which is true only
* if this is an IP datagram and is the first or
* only fragment of that datagram.
*/
gen_and(gen_proto_abbrev(cstate, proto), b = gen_ipfrag(cstate));
if (inst->b)
gen_and(inst->b, b);
gen_and(gen_proto_abbrev(cstate, Q_IP), b);
inst->b = b;
break;
case Q_ICMPV6:
/*
* Do the computation only if the packet contains
* the protocol in question.
*/
b = gen_proto_abbrev(cstate, Q_IPV6);
if (inst->b) {
gen_and(inst->b, b);
}
inst->b = b;
/*
* Check if we have an icmp6 next header
*/
b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58);
if (inst->b) {
gen_and(inst->b, b);
}
inst->b = b;
s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
/*
* If "s" is non-null, it has code to arrange that the
* X register contains the variable part of the offset
* of the link-layer payload. Add to it the offset
* computed into the register specified by "index",
* and move that into the X register. Otherwise, just
* load into the X register the offset computed into
* the register specified by "index".
*/
if (s != NULL) {
sappend(s, xfer_to_a(cstate, inst));
sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
} else {
s = xfer_to_x(cstate, inst);
}
/*
* Load the item at the sum of the offset we've put in the
* X register, the offset of the start of the network
* layer header from the beginning of the link-layer
* payload, and the constant part of the offset of the
* start of the link-layer payload.
*/
tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 40;
sappend(s, tmp);
sappend(inst->s, s);
break;
}
inst->regno = regno;
s = new_stmt(cstate, BPF_ST);
s->s.k = regno;
sappend(inst->s, s);
return inst;
}
struct block *
gen_relation(compiler_state_t *cstate, int code, struct arth *a0,
struct arth *a1, int reversed)
{
struct slist *s0, *s1, *s2;
struct block *b, *tmp;
s0 = xfer_to_x(cstate, a1);
s1 = xfer_to_a(cstate, a0);
if (code == BPF_JEQ) {
s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X);
b = new_block(cstate, JMP(code));
sappend(s1, s2);
}
else
b = new_block(cstate, BPF_JMP|code|BPF_X);
if (reversed)
gen_not(b);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
b->stmts = a0->s;
free_reg(cstate, a0->regno);
free_reg(cstate, a1->regno);
/* 'and' together protocol checks */
if (a0->b) {
if (a1->b) {
gen_and(a0->b, tmp = a1->b);
}
else
tmp = a0->b;
} else
tmp = a1->b;
if (tmp)
gen_and(tmp, b);
return b;
}
struct arth *
gen_loadlen(compiler_state_t *cstate)
{
int regno = alloc_reg(cstate);
struct arth *a = (struct arth *)newchunk(cstate, sizeof(*a));
struct slist *s;
s = new_stmt(cstate, BPF_LD|BPF_LEN);
s->next = new_stmt(cstate, BPF_ST);
s->next->s.k = regno;
a->s = s;
a->regno = regno;
return a;
}
struct arth *
gen_loadi(compiler_state_t *cstate, int val)
{
struct arth *a;
struct slist *s;
int reg;
a = (struct arth *)newchunk(cstate, sizeof(*a));
reg = alloc_reg(cstate);
s = new_stmt(cstate, BPF_LD|BPF_IMM);
s->s.k = val;
s->next = new_stmt(cstate, BPF_ST);
s->next->s.k = reg;
a->s = s;
a->regno = reg;
return a;
}
struct arth *
gen_neg(compiler_state_t *cstate, struct arth *a)
{
struct slist *s;
s = xfer_to_a(cstate, a);
sappend(a->s, s);
s = new_stmt(cstate, BPF_ALU|BPF_NEG);
s->s.k = 0;
sappend(a->s, s);
s = new_stmt(cstate, BPF_ST);
s->s.k = a->regno;
sappend(a->s, s);
return a;
}
struct arth *
gen_arth(compiler_state_t *cstate, int code, struct arth *a0,
struct arth *a1)
{
struct slist *s0, *s1, *s2;
/*
* Disallow division by, or modulus by, zero; we do this here
* so that it gets done even if the optimizer is disabled.
*/
if (code == BPF_DIV) {
if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
bpf_error(cstate, "division by zero");
} else if (code == BPF_MOD) {
if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
bpf_error(cstate, "modulus by zero");
}
s0 = xfer_to_x(cstate, a1);
s1 = xfer_to_a(cstate, a0);
s2 = new_stmt(cstate, BPF_ALU|BPF_X|code);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
free_reg(cstate, a0->regno);
free_reg(cstate, a1->regno);
s0 = new_stmt(cstate, BPF_ST);
a0->regno = s0->s.k = alloc_reg(cstate);
sappend(a0->s, s0);
return a0;
}
/*
* Initialize the table of used registers and the current register.
*/
static void
init_regs(compiler_state_t *cstate)
{
cstate->curreg = 0;
memset(cstate->regused, 0, sizeof cstate->regused);
}
/*
* Return the next free register.
*/
static int
alloc_reg(compiler_state_t *cstate)
{
int n = BPF_MEMWORDS;
while (--n >= 0) {
if (cstate->regused[cstate->curreg])
cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS;
else {
cstate->regused[cstate->curreg] = 1;
return cstate->curreg;
}
}
bpf_error(cstate, "too many registers needed to evaluate expression");
/* NOTREACHED */
}
/*
* Return a register to the table so it can
* be used later.
*/
static void
free_reg(compiler_state_t *cstate, int n)
{
cstate->regused[n] = 0;
}
static struct block *
gen_len(compiler_state_t *cstate, int jmp, int n)
{
struct slist *s;
struct block *b;
s = new_stmt(cstate, BPF_LD|BPF_LEN);
b = new_block(cstate, JMP(jmp));
b->stmts = s;
b->s.k = n;
return b;
}
struct block *
gen_greater(compiler_state_t *cstate, int n)
{
return gen_len(cstate, BPF_JGE, n);
}
/*
* Actually, this is less than or equal.
*/
struct block *
gen_less(compiler_state_t *cstate, int n)
{
struct block *b;
b = gen_len(cstate, BPF_JGT, n);
gen_not(b);
return b;
}
/*
* This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
* the beginning of the link-layer header.
* XXX - that means you can't test values in the radiotap header, but
* as that header is difficult if not impossible to parse generally
* without a loop, that might not be a severe problem. A new keyword
* "radio" could be added for that, although what you'd really want
* would be a way of testing particular radio header values, which
* would generate code appropriate to the radio header in question.
*/
struct block *
gen_byteop(compiler_state_t *cstate, int op, int idx, int val)
{
struct block *b;
struct slist *s;
switch (op) {
default:
abort();
case '=':
return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
case '<':
b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
return b;
case '>':
b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
return b;
case '|':
s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K);
break;
case '&':
s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
break;
}
s->s.k = val;
b = new_block(cstate, JMP(BPF_JEQ));
b->stmts = s;
gen_not(b);
return b;
}
static const u_char abroadcast[] = { 0x0 };
struct block *
gen_broadcast(compiler_state_t *cstate, int proto)
{
bpf_u_int32 hostmask;
struct block *b0, *b1, *b2;
static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
switch (cstate->linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
return gen_ahostop(cstate, abroadcast, Q_DST);
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b1 = gen_prevlinkhdr_check(cstate);
b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
if (b1 != NULL)
gen_and(b1, b0);
return b0;
case DLT_FDDI:
return gen_fhostop(cstate, ebroadcast, Q_DST);
case DLT_IEEE802:
return gen_thostop(cstate, ebroadcast, Q_DST);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
return gen_wlanhostop(cstate, ebroadcast, Q_DST);
case DLT_IP_OVER_FC:
return gen_ipfchostop(cstate, ebroadcast, Q_DST);
default:
bpf_error(cstate, "not a broadcast link");
}
break;
case Q_IP:
/*
* We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
* as an indication that we don't know the netmask, and fail
* in that case.
*/
if (cstate->netmask == PCAP_NETMASK_UNKNOWN)
bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported");
b0 = gen_linktype(cstate, ETHERTYPE_IP);
hostmask = ~cstate->netmask;
b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, (bpf_int32)0, hostmask);
b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W,
(bpf_int32)(~0 & hostmask), hostmask);
gen_or(b1, b2);
gen_and(b0, b2);
return b2;
}
bpf_error(cstate, "only link-layer/IP broadcast filters supported");
/* NOTREACHED */
}
/*
* Generate code to test the low-order bit of a MAC address (that's
* the bottom bit of the *first* byte).
*/
static struct block *
gen_mac_multicast(compiler_state_t *cstate, int offset)
{
register struct block *b0;
register struct slist *s;
/* link[offset] & 1 != 0 */
s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B);
b0 = new_block(cstate, JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
struct block *
gen_multicast(compiler_state_t *cstate, int proto)
{
register struct block *b0, *b1, *b2;
register struct slist *s;
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
switch (cstate->linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
/* all ARCnet multicasts use the same address */
return gen_ahostop(cstate, abroadcast, Q_DST);
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b1 = gen_prevlinkhdr_check(cstate);
/* ether[0] & 1 != 0 */
b0 = gen_mac_multicast(cstate, 0);
if (b1 != NULL)
gen_and(b1, b0);
return b0;
case DLT_FDDI:
/*
* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
*
* XXX - was that referring to bit-order issues?
*/
/* fddi[1] & 1 != 0 */
return gen_mac_multicast(cstate, 1);
case DLT_IEEE802:
/* tr[2] & 1 != 0 */
return gen_mac_multicast(cstate, 2);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_mac_multicast(cstate, 16);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_mac_multicast(cstate, 4);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b2 = new_block(cstate, JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_mac_multicast(cstate, 4);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
b1 = new_block(cstate, JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case DLT_IP_OVER_FC:
b0 = gen_mac_multicast(cstate, 2);
return b0;
default:
break;
}
/* Link not known to support multicasts */
break;
case Q_IP:
b0 = gen_linktype(cstate, ETHERTYPE_IP);
b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, (bpf_int32)224);
gen_and(b0, b1);
return b1;
case Q_IPV6:
b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, (bpf_int32)255);
gen_and(b0, b1);
return b1;
}
bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
/* NOTREACHED */
}
/*
* Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
* Outbound traffic is sent by this machine, while inbound traffic is
* sent by a remote machine (and may include packets destined for a
* unicast or multicast link-layer address we are not subscribing to).
* These are the same definitions implemented by pcap_setdirection().
* Capturing only unicast traffic destined for this host is probably
* better accomplished using a higher-layer filter.
*/
struct block *
gen_inbound(compiler_state_t *cstate, int dir)
{
register struct block *b0;
/*
* Only some data link types support inbound/outbound qualifiers.
*/
switch (cstate->linktype) {
case DLT_SLIP:
b0 = gen_relation(cstate, BPF_JEQ,
gen_load(cstate, Q_LINK, gen_loadi(cstate, 0), 1),
gen_loadi(cstate, 0),
dir);
break;
case DLT_IPNET:
if (dir) {
/* match outgoing packets */
b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND);
} else {
/* match incoming packets */
b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND);
}
break;
case DLT_LINUX_SLL:
/* match outgoing packets */
b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING);
if (!dir) {
/* to filter on inbound traffic, invert the match */
gen_not(b0);
}
break;
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
(bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
break;
#endif
case DLT_PPP_PPPD:
if (dir) {
/* match outgoing packets */
b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT);
} else {
/* match incoming packets */
b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN);
}
break;
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_ATM1:
case DLT_JUNIPER_ATM2:
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_PPPOE_ATM:
case DLT_JUNIPER_GGSN:
case DLT_JUNIPER_ES:
case DLT_JUNIPER_MONITOR:
case DLT_JUNIPER_SERVICES:
case DLT_JUNIPER_ETHER:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_FRELAY:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_VP:
case DLT_JUNIPER_ST:
case DLT_JUNIPER_ISM:
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
/* juniper flags (including direction) are stored
* the byte after the 3-byte magic number */
if (dir) {
/* match outgoing packets */
b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01);
} else {
/* match incoming packets */
b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01);
}
break;
default:
/*
* If we have packet meta-data indicating a direction,
* and that metadata can be checked by BPF code, check
* it. Otherwise, give up, as this link-layer type has
* nothing in the packet data.
*
* Currently, the only platform where a BPF filter can
* check that metadata is Linux with the in-kernel
* BPF interpreter. If other packet capture mechanisms
* and BPF filters also supported this, it would be
* nice. It would be even better if they made that
* metadata available so that we could provide it
* with newer capture APIs, allowing it to be saved
* in pcapng files.
*/
#if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
/*
* This is Linux with PF_PACKET support.
* If this is a *live* capture, we can look at
* special meta-data in the filter expression;
* if it's a savefile, we can't.
*/
if (cstate->bpf_pcap->rfile != NULL) {
/* We have a FILE *, so this is a savefile */
bpf_error(cstate, "inbound/outbound not supported on linktype %d when reading savefiles",
cstate->linktype);
b0 = NULL;
/* NOTREACHED */
}
/* match outgoing packets */
b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
PACKET_OUTGOING);
if (!dir) {
/* to filter on inbound traffic, invert the match */
gen_not(b0);
}
#else /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
bpf_error(cstate, "inbound/outbound not supported on linktype %d",
cstate->linktype);
/* NOTREACHED */
#endif /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
}
return (b0);
}
#ifdef HAVE_NET_PFVAR_H
/* PF firewall log matched interface */
struct block *
gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
{
struct block *b0;
u_int len, off;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "ifname supported only on PF linktype");
/* NOTREACHED */
}
len = sizeof(((struct pfloghdr *)0)->ifname);
off = offsetof(struct pfloghdr, ifname);
if (strlen(ifname) >= len) {
bpf_error(cstate, "ifname interface names can only be %d characters",
len-1);
/* NOTREACHED */
}
b0 = gen_bcmp(cstate, OR_LINKHDR, off, strlen(ifname), (const u_char *)ifname);
return (b0);
}
/* PF firewall log ruleset name */
struct block *
gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
{
struct block *b0;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "ruleset supported only on PF linktype");
/* NOTREACHED */
}
if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
bpf_error(cstate, "ruleset names can only be %ld characters",
(long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
/* NOTREACHED */
}
b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
strlen(ruleset), (const u_char *)ruleset);
return (b0);
}
/* PF firewall log rule number */
struct block *
gen_pf_rnr(compiler_state_t *cstate, int rnr)
{
struct block *b0;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "rnr supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
(bpf_int32)rnr);
return (b0);
}
/* PF firewall log sub-rule number */
struct block *
gen_pf_srnr(compiler_state_t *cstate, int srnr)
{
struct block *b0;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "srnr supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
(bpf_int32)srnr);
return (b0);
}
/* PF firewall log reason code */
struct block *
gen_pf_reason(compiler_state_t *cstate, int reason)
{
struct block *b0;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "reason supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
(bpf_int32)reason);
return (b0);
}
/* PF firewall log action */
struct block *
gen_pf_action(compiler_state_t *cstate, int action)
{
struct block *b0;
if (cstate->linktype != DLT_PFLOG) {
bpf_error(cstate, "action supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
(bpf_int32)action);
return (b0);
}
#else /* !HAVE_NET_PFVAR_H */
struct block *
gen_pf_ifname(compiler_state_t *cstate, const char *ifname _U_)
{
bpf_error(cstate, "libpcap was compiled without pf support");
/* NOTREACHED */
}
struct block *
gen_pf_ruleset(compiler_state_t *cstate, char *ruleset _U_)
{
bpf_error(cstate, "libpcap was compiled on a machine without pf support");
/* NOTREACHED */
}
struct block *
gen_pf_rnr(compiler_state_t *cstate, int rnr _U_)
{
bpf_error(cstate, "libpcap was compiled on a machine without pf support");
/* NOTREACHED */
}
struct block *
gen_pf_srnr(compiler_state_t *cstate, int srnr _U_)
{
bpf_error(cstate, "libpcap was compiled on a machine without pf support");
/* NOTREACHED */
}
struct block *
gen_pf_reason(compiler_state_t *cstate, int reason _U_)
{
bpf_error(cstate, "libpcap was compiled on a machine without pf support");
/* NOTREACHED */
}
struct block *
gen_pf_action(compiler_state_t *cstate, int action _U_)
{
bpf_error(cstate, "libpcap was compiled on a machine without pf support");
/* NOTREACHED */
}
#endif /* HAVE_NET_PFVAR_H */
/* IEEE 802.11 wireless header */
struct block *
gen_p80211_type(compiler_state_t *cstate, int type, int mask)
{
struct block *b0;
switch (cstate->linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, (bpf_int32)type,
(bpf_int32)mask);
break;
default:
bpf_error(cstate, "802.11 link-layer types supported only on 802.11");
/* NOTREACHED */
}
return (b0);
}
struct block *
gen_p80211_fcdir(compiler_state_t *cstate, int fcdir)
{
struct block *b0;
switch (cstate->linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
break;
default:
bpf_error(cstate, "frame direction supported only with 802.11 headers");
/* NOTREACHED */
}
b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, (bpf_int32)fcdir,
(bpf_u_int32)IEEE80211_FC1_DIR_MASK);
return (b0);
}
struct block *
gen_acode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
{
switch (cstate->linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
q.proto == Q_LINK)
return (gen_ahostop(cstate, eaddr, (int)q.dir));
else {
bpf_error(cstate, "ARCnet address used in non-arc expression");
/* NOTREACHED */
}
break;
default:
bpf_error(cstate, "aid supported only on ARCnet");
/* NOTREACHED */
}
}
static struct block *
gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
{
register struct block *b0, *b1;
switch (dir) {
/* src comes first, different from Ethernet */
case Q_SRC:
return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr);
case Q_DST:
return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr);
case Q_AND:
b0 = gen_ahostop(cstate, eaddr, Q_SRC);
b1 = gen_ahostop(cstate, eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ahostop(cstate, eaddr, Q_SRC);
b1 = gen_ahostop(cstate, eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
break;
case Q_ADDR2:
bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
break;
case Q_ADDR3:
bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
break;
case Q_ADDR4:
bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
break;
case Q_RA:
bpf_error(cstate, "'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error(cstate, "'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
static struct block *
gen_vlan_tpid_test(compiler_state_t *cstate)
{
struct block *b0, *b1;
/* check for VLAN, including QinQ */
b0 = gen_linktype(cstate, ETHERTYPE_8021Q);
b1 = gen_linktype(cstate, ETHERTYPE_8021AD);
gen_or(b0,b1);
b0 = b1;
b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ);
gen_or(b0,b1);
return b1;
}
static struct block *
gen_vlan_vid_test(compiler_state_t *cstate, int vlan_num)
{
return gen_mcmp(cstate, OR_LINKPL, 0, BPF_H, (bpf_int32)vlan_num, 0x0fff);
}
static struct block *
gen_vlan_no_bpf_extensions(compiler_state_t *cstate, int vlan_num)
{
struct block *b0, *b1;
b0 = gen_vlan_tpid_test(cstate);
if (vlan_num >= 0) {
b1 = gen_vlan_vid_test(cstate, vlan_num);
gen_and(b0, b1);
b0 = b1;
}
/*
* Both payload and link header type follow the VLAN tags so that
* both need to be updated.
*/
cstate->off_linkpl.constant_part += 4;
cstate->off_linktype.constant_part += 4;
return b0;
}
#if defined(SKF_AD_VLAN_TAG_PRESENT)
/* add v to variable part of off */
static void
gen_vlan_vloffset_add(compiler_state_t *cstate, bpf_abs_offset *off, int v, struct slist *s)
{
struct slist *s2;
if (!off->is_variable)
off->is_variable = 1;
if (off->reg == -1)
off->reg = alloc_reg(cstate);
s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
s2->s.k = off->reg;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = v;
sappend(s, s2);
s2 = new_stmt(cstate, BPF_ST);
s2->s.k = off->reg;
sappend(s, s2);
}
/*
* patch block b_tpid (VLAN TPID test) to update variable parts of link payload
* and link type offsets first
*/
static void
gen_vlan_patch_tpid_test(compiler_state_t *cstate, struct block *b_tpid)
{
struct slist s;
/* offset determined at run time, shift variable part */
s.next = NULL;
cstate->is_vlan_vloffset = 1;
gen_vlan_vloffset_add(cstate, &cstate->off_linkpl, 4, &s);
gen_vlan_vloffset_add(cstate, &cstate->off_linktype, 4, &s);
/* we get a pointer to a chain of or-ed blocks, patch first of them */
sappend(s.next, b_tpid->head->stmts);
b_tpid->head->stmts = s.next;
}
/*
* patch block b_vid (VLAN id test) to load VID value either from packet
* metadata (using BPF extensions) if SKF_AD_VLAN_TAG_PRESENT is true
*/
static void
gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
{
struct slist *s, *s2, *sjeq;
unsigned cnt;
s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
/* true -> next instructions, false -> beginning of b_vid */
sjeq = new_stmt(cstate, JMP(BPF_JEQ));
sjeq->s.k = 1;
sjeq->s.jf = b_vid->stmts;
sappend(s, sjeq);
s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
sappend(s, s2);
sjeq->s.jt = s2;
/* jump to the test in b_vid (bypass loading VID from packet data) */
cnt = 0;
for (s2 = b_vid->stmts; s2; s2 = s2->next)
cnt++;
s2 = new_stmt(cstate, JMP(BPF_JA));
s2->s.k = cnt;
sappend(s, s2);
/* insert our statements at the beginning of b_vid */
sappend(s, b_vid->stmts);
b_vid->stmts = s;
}
/*
* Generate check for "vlan" or "vlan <id>" on systems with support for BPF
* extensions. Even if kernel supports VLAN BPF extensions, (outermost) VLAN
* tag can be either in metadata or in packet data; therefore if the
* SKF_AD_VLAN_TAG_PRESENT test is negative, we need to check link
* header for VLAN tag. As the decision is done at run time, we need
* update variable part of the offsets
*/
static struct block *
gen_vlan_bpf_extensions(compiler_state_t *cstate, int vlan_num)
{
struct block *b0, *b_tpid, *b_vid = NULL;
struct slist *s;
/* generate new filter code based on extracting packet
* metadata */
s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
b0 = new_block(cstate, JMP(BPF_JEQ));
b0->stmts = s;
b0->s.k = 1;
/*
* This is tricky. We need to insert the statements updating variable
* parts of offsets before the the traditional TPID and VID tests so
* that they are called whenever SKF_AD_VLAN_TAG_PRESENT fails but
* we do not want this update to affect those checks. That's why we
* generate both test blocks first and insert the statements updating
* variable parts of both offsets after that. This wouldn't work if
* there already were variable length link header when entering this
* function but gen_vlan_bpf_extensions() isn't called in that case.
*/
b_tpid = gen_vlan_tpid_test(cstate);
if (vlan_num >= 0)
b_vid = gen_vlan_vid_test(cstate, vlan_num);
gen_vlan_patch_tpid_test(cstate, b_tpid);
gen_or(b0, b_tpid);
b0 = b_tpid;
if (vlan_num >= 0) {
gen_vlan_patch_vid_test(cstate, b_vid);
gen_and(b0, b_vid);
b0 = b_vid;
}
return b0;
}
#endif
/*
* support IEEE 802.1Q VLAN trunk over ethernet
*/
struct block *
gen_vlan(compiler_state_t *cstate, int vlan_num)
{
struct block *b0;
/* can't check for VLAN-encapsulated packets inside MPLS */
if (cstate->label_stack_depth > 0)
bpf_error(cstate, "no VLAN match after MPLS");
/*
* Check for a VLAN packet, and then change the offsets to point
* to the type and data fields within the VLAN packet. Just
* increment the offsets, so that we can support a hierarchy, e.g.
* "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
* VLAN 100.
*
* XXX - this is a bit of a kludge. If we were to split the
* compiler into a parser that parses an expression and
* generates an expression tree, and a code generator that
* takes an expression tree (which could come from our
* parser or from some other parser) and generates BPF code,
* we could perhaps make the offsets parameters of routines
* and, in the handler for an "AND" node, pass to subnodes
* other than the VLAN node the adjusted offsets.
*
* This would mean that "vlan" would, instead of changing the
* behavior of *all* tests after it, change only the behavior
* of tests ANDed with it. That would change the documented
* semantics of "vlan", which might break some expressions.
* However, it would mean that "(vlan and ip) or ip" would check
* both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
* checking only for VLAN-encapsulated IP, so that could still
* be considered worth doing; it wouldn't break expressions
* that are of the form "vlan and ..." or "vlan N and ...",
* which I suspect are the most common expressions involving
* "vlan". "vlan or ..." doesn't necessarily do what the user
* would really want, now, as all the "or ..." tests would
* be done assuming a VLAN, even though the "or" could be viewed
* as meaning "or, if this isn't a VLAN packet...".
*/
switch (cstate->linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
#if defined(SKF_AD_VLAN_TAG_PRESENT)
/* Verify that this is the outer part of the packet and
* not encapsulated somehow. */
if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable &&
cstate->off_linkhdr.constant_part ==
cstate->off_outermostlinkhdr.constant_part) {
/*
* Do we need special VLAN handling?
*/
if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
b0 = gen_vlan_bpf_extensions(cstate, vlan_num);
else
b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
} else
#endif
b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
break;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
break;
default:
bpf_error(cstate, "no VLAN support for data link type %d",
cstate->linktype);
/*NOTREACHED*/
}
cstate->vlan_stack_depth++;
return (b0);
}
/*
* support for MPLS
*/
struct block *
gen_mpls(compiler_state_t *cstate, int label_num)
{
struct block *b0, *b1;
if (cstate->label_stack_depth > 0) {
/* just match the bottom-of-stack bit clear */
b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01);
} else {
/*
* We're not in an MPLS stack yet, so check the link-layer
* type against MPLS.
*/
switch (cstate->linktype) {
case DLT_C_HDLC: /* fall through */
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b0 = gen_linktype(cstate, ETHERTYPE_MPLS);
break;
case DLT_PPP:
b0 = gen_linktype(cstate, PPP_MPLS_UCAST);
break;
/* FIXME add other DLT_s ...
* for Frame-Relay/and ATM this may get messy due to SNAP headers
* leave it for now */
default:
bpf_error(cstate, "no MPLS support for data link type %d",
cstate->linktype);
/*NOTREACHED*/
break;
}
}
/* If a specific MPLS label is requested, check it */
if (label_num >= 0) {
label_num = label_num << 12; /* label is shifted 12 bits on the wire */
b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, (bpf_int32)label_num,
0xfffff000); /* only compare the first 20 bits */
gen_and(b0, b1);
b0 = b1;
}
/*
* Change the offsets to point to the type and data fields within
* the MPLS packet. Just increment the offsets, so that we
* can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
* capture packets with an outer label of 100000 and an inner
* label of 1024.
*
* Increment the MPLS stack depth as well; this indicates that
* we're checking MPLS-encapsulated headers, to make sure higher
* level code generators don't try to match against IP-related
* protocols such as Q_ARP, Q_RARP etc.
*
* XXX - this is a bit of a kludge. See comments in gen_vlan().
*/
cstate->off_nl_nosnap += 4;
cstate->off_nl += 4;
cstate->label_stack_depth++;
return (b0);
}
/*
* Support PPPOE discovery and session.
*/
struct block *
gen_pppoed(compiler_state_t *cstate)
{
/* check for PPPoE discovery */
return gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOED);
}
struct block *
gen_pppoes(compiler_state_t *cstate, int sess_num)
{
struct block *b0, *b1;
/*
* Test against the PPPoE session link-layer type.
*/
b0 = gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOES);
/* If a specific session is requested, check PPPoE session id */
if (sess_num >= 0) {
b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W,
(bpf_int32)sess_num, 0x0000ffff);
gen_and(b0, b1);
b0 = b1;
}
/*
* Change the offsets to point to the type and data fields within
* the PPP packet, and note that this is PPPoE rather than
* raw PPP.
*
* XXX - this is a bit of a kludge. If we were to split the
* compiler into a parser that parses an expression and
* generates an expression tree, and a code generator that
* takes an expression tree (which could come from our
* parser or from some other parser) and generates BPF code,
* we could perhaps make the offsets parameters of routines
* and, in the handler for an "AND" node, pass to subnodes
* other than the PPPoE node the adjusted offsets.
*
* This would mean that "pppoes" would, instead of changing the
* behavior of *all* tests after it, change only the behavior
* of tests ANDed with it. That would change the documented
* semantics of "pppoes", which might break some expressions.
* However, it would mean that "(pppoes and ip) or ip" would check
* both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
* checking only for VLAN-encapsulated IP, so that could still
* be considered worth doing; it wouldn't break expressions
* that are of the form "pppoes and ..." which I suspect are the
* most common expressions involving "pppoes". "pppoes or ..."
* doesn't necessarily do what the user would really want, now,
* as all the "or ..." tests would be done assuming PPPoE, even
* though the "or" could be viewed as meaning "or, if this isn't
* a PPPoE packet...".
*
* The "network-layer" protocol is PPPoE, which has a 6-byte
* PPPoE header, followed by a PPP packet.
*
* There is no HDLC encapsulation for the PPP packet (it's
* encapsulated in PPPoES instead), so the link-layer type
* starts at the first byte of the PPP packet. For PPPoE,
* that offset is relative to the beginning of the total
* link-layer payload, including any 802.2 LLC header, so
* it's 6 bytes past cstate->off_nl.
*/
PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable,
cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */
cstate->off_linkpl.reg);
cstate->off_linktype = cstate->off_linkhdr;
cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2;
cstate->off_nl = 0;
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
return b0;
}
/* Check that this is Geneve and the VNI is correct if
* specified. Parameterized to handle both IPv4 and IPv6. */
static struct block *
gen_geneve_check(compiler_state_t *cstate,
struct block *(*gen_portfn)(compiler_state_t *, int, int, int),
enum e_offrel offrel, int vni)
{
struct block *b0, *b1;
b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST);
/* Check that we are operating on version 0. Otherwise, we
* can't decode the rest of the fields. The version is 2 bits
* in the first byte of the Geneve header. */
b1 = gen_mcmp(cstate, offrel, 8, BPF_B, (bpf_int32)0, 0xc0);
gen_and(b0, b1);
b0 = b1;
if (vni >= 0) {
vni <<= 8; /* VNI is in the upper 3 bytes */
b1 = gen_mcmp(cstate, offrel, 12, BPF_W, (bpf_int32)vni,
0xffffff00);
gen_and(b0, b1);
b0 = b1;
}
return b0;
}
/* The IPv4 and IPv6 Geneve checks need to do two things:
* - Verify that this actually is Geneve with the right VNI.
* - Place the IP header length (plus variable link prefix if
* needed) into register A to be used later to compute
* the inner packet offsets. */
static struct block *
gen_geneve4(compiler_state_t *cstate, int vni)
{
struct block *b0, *b1;
struct slist *s, *s1;
b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni);
/* Load the IP header length into A. */
s = gen_loadx_iphdrlen(cstate);
s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
sappend(s, s1);
/* Forcibly append these statements to the true condition
* of the protocol check by creating a new block that is
* always true and ANDing them. */
b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
b1->stmts = s;
b1->s.k = 0;
gen_and(b0, b1);
return b1;
}
static struct block *
gen_geneve6(compiler_state_t *cstate, int vni)
{
struct block *b0, *b1;
struct slist *s, *s1;
b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni);
/* Load the IP header length. We need to account for a
* variable length link prefix if there is one. */
s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
if (s) {
s1 = new_stmt(cstate, BPF_LD|BPF_IMM);
s1->s.k = 40;
sappend(s, s1);
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
s1->s.k = 0;
sappend(s, s1);
} else {
s = new_stmt(cstate, BPF_LD|BPF_IMM);
s->s.k = 40;
}
/* Forcibly append these statements to the true condition
* of the protocol check by creating a new block that is
* always true and ANDing them. */
s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s, s1);
b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
b1->stmts = s;
b1->s.k = 0;
gen_and(b0, b1);
return b1;
}
/* We need to store three values based on the Geneve header::
* - The offset of the linktype.
* - The offset of the end of the Geneve header.
* - The offset of the end of the encapsulated MAC header. */
static struct slist *
gen_geneve_offsets(compiler_state_t *cstate)
{
struct slist *s, *s1, *s_proto;
/* First we need to calculate the offset of the Geneve header
* itself. This is composed of the IP header previously calculated
* (include any variable link prefix) and stored in A plus the
* fixed sized headers (fixed link prefix, MAC length, and UDP
* header). */
s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8;
/* Stash this in X since we'll need it later. */
s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s, s1);
/* The EtherType in Geneve is 2 bytes in. Calculate this and
* store it. */
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s1->s.k = 2;
sappend(s, s1);
cstate->off_linktype.reg = alloc_reg(cstate);
cstate->off_linktype.is_variable = 1;
cstate->off_linktype.constant_part = 0;
s1 = new_stmt(cstate, BPF_ST);
s1->s.k = cstate->off_linktype.reg;
sappend(s, s1);
/* Load the Geneve option length and mask and shift to get the
* number of bytes. It is stored in the first byte of the Geneve
* header. */
s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
s1->s.k = 0;
sappend(s, s1);
s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
s1->s.k = 0x3f;
sappend(s, s1);
s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
s1->s.k = 4;
sappend(s, s1);
/* Add in the rest of the Geneve base header. */
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s1->s.k = 8;
sappend(s, s1);
/* Add the Geneve header length to its offset and store. */
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
s1->s.k = 0;
sappend(s, s1);
/* Set the encapsulated type as Ethernet. Even though we may
* not actually have Ethernet inside there are two reasons this
* is useful:
* - The linktype field is always in EtherType format regardless
* of whether it is in Geneve or an inner Ethernet frame.
* - The only link layer that we have specific support for is
* Ethernet. We will confirm that the packet actually is
* Ethernet at runtime before executing these checks. */
PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate));
s1 = new_stmt(cstate, BPF_ST);
s1->s.k = cstate->off_linkhdr.reg;
sappend(s, s1);
/* Calculate whether we have an Ethernet header or just raw IP/
* MPLS/etc. If we have Ethernet, advance the end of the MAC offset
* and linktype by 14 bytes so that the network header can be found
* seamlessly. Otherwise, keep what we've calculated already. */
/* We have a bare jmp so we can't use the optimizer. */
cstate->no_optimize = 1;
/* Load the EtherType in the Geneve header, 2 bytes in. */
s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H);
s1->s.k = 2;
sappend(s, s1);
/* Load X with the end of the Geneve header. */
s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
s1->s.k = cstate->off_linkhdr.reg;
sappend(s, s1);
/* Check if the EtherType is Transparent Ethernet Bridging. At the
* end of this check, we should have the total length in X. In
* the non-Ethernet case, it's already there. */
s_proto = new_stmt(cstate, JMP(BPF_JEQ));
s_proto->s.k = ETHERTYPE_TEB;
sappend(s, s_proto);
s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
sappend(s, s1);
s_proto->s.jt = s1;
/* Since this is Ethernet, use the EtherType of the payload
* directly as the linktype. Overwrite what we already have. */
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s1->s.k = 12;
sappend(s, s1);
s1 = new_stmt(cstate, BPF_ST);
s1->s.k = cstate->off_linktype.reg;
sappend(s, s1);
/* Advance two bytes further to get the end of the Ethernet
* header. */
s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
s1->s.k = 2;
sappend(s, s1);
/* Move the result to X. */
s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
sappend(s, s1);
/* Store the final result of our linkpl calculation. */
cstate->off_linkpl.reg = alloc_reg(cstate);
cstate->off_linkpl.is_variable = 1;
cstate->off_linkpl.constant_part = 0;
s1 = new_stmt(cstate, BPF_STX);
s1->s.k = cstate->off_linkpl.reg;
sappend(s, s1);
s_proto->s.jf = s1;
cstate->off_nl = 0;
return s;
}
/* Check to see if this is a Geneve packet. */
struct block *
gen_geneve(compiler_state_t *cstate, int vni)
{
struct block *b0, *b1;
struct slist *s;
b0 = gen_geneve4(cstate, vni);
b1 = gen_geneve6(cstate, vni);
gen_or(b0, b1);
b0 = b1;
/* Later filters should act on the payload of the Geneve frame,
* update all of the header pointers. Attach this code so that
* it gets executed in the event that the Geneve filter matches. */
s = gen_geneve_offsets(cstate);
b1 = gen_true(cstate);
sappend(s, b1->stmts);
b1->stmts = s;
gen_and(b0, b1);
cstate->is_geneve = 1;
return b1;
}
/* Check that the encapsulated frame has a link layer header
* for Ethernet filters. */
static struct block *
gen_geneve_ll_check(compiler_state_t *cstate)
{
struct block *b0;
struct slist *s, *s1;
/* The easiest way to see if there is a link layer present
* is to check if the link layer header and payload are not
* the same. */
/* Geneve always generates pure variable offsets so we can
* compare only the registers. */
s = new_stmt(cstate, BPF_LD|BPF_MEM);
s->s.k = cstate->off_linkhdr.reg;
s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
s1->s.k = cstate->off_linkpl.reg;
sappend(s, s1);
b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
b0->stmts = s;
b0->s.k = 0;
gen_not(b0);
return b0;
}
struct block *
gen_atmfield_code(compiler_state_t *cstate, int atmfield, bpf_int32 jvalue,
bpf_u_int32 jtype, int reverse)
{
struct block *b0;
switch (atmfield) {
case A_VPI:
if (!cstate->is_atm)
bpf_error(cstate, "'vpi' supported only on raw ATM");
if (cstate->off_vpi == OFFSET_NOT_SET)
abort();
b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffff, jtype,
reverse, jvalue);
break;
case A_VCI:
if (!cstate->is_atm)
bpf_error(cstate, "'vci' supported only on raw ATM");
if (cstate->off_vci == OFFSET_NOT_SET)
abort();
b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffff, jtype,
reverse, jvalue);
break;
case A_PROTOTYPE:
if (cstate->off_proto == OFFSET_NOT_SET)
abort(); /* XXX - this isn't on FreeBSD */
b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0f, jtype,
reverse, jvalue);
break;
case A_MSGTYPE:
if (cstate->off_payload == OFFSET_NOT_SET)
abort();
b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
0xffffffff, jtype, reverse, jvalue);
break;
case A_CALLREFTYPE:
if (!cstate->is_atm)
bpf_error(cstate, "'callref' supported only on raw ATM");
if (cstate->off_proto == OFFSET_NOT_SET)
abort();
b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffff,
jtype, reverse, jvalue);
break;
default:
abort();
}
return b0;
}
struct block *
gen_atmtype_abbrev(compiler_state_t *cstate, int type)
{
struct block *b0, *b1;
switch (type) {
case A_METAC:
/* Get all packets in Meta signalling Circuit */
if (!cstate->is_atm)
bpf_error(cstate, "'metac' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 1, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_BCC:
/* Get all packets in Broadcast Circuit*/
if (!cstate->is_atm)
bpf_error(cstate, "'bcc' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 2, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_OAMF4SC:
/* Get all cells in Segment OAM F4 circuit*/
if (!cstate->is_atm)
bpf_error(cstate, "'oam4sc' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_OAMF4EC:
/* Get all cells in End-to-End OAM F4 Circuit*/
if (!cstate->is_atm)
bpf_error(cstate, "'oam4ec' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_SC:
/* Get all packets in connection Signalling Circuit */
if (!cstate->is_atm)
bpf_error(cstate, "'sc' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 5, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_ILMIC:
/* Get all packets in ILMI Circuit */
if (!cstate->is_atm)
bpf_error(cstate, "'ilmic' supported only on raw ATM");
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 16, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_LANE:
/* Get all LANE packets */
if (!cstate->is_atm)
bpf_error(cstate, "'lane' supported only on raw ATM");
b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
/*
* Arrange that all subsequent tests assume LANE
* rather than LLC-encapsulated packets, and set
* the offsets appropriately for LANE-encapsulated
* Ethernet.
*
* We assume LANE means Ethernet, not Token Ring.
*/
PUSH_LINKHDR(cstate, DLT_EN10MB, 0,
cstate->off_payload + 2, /* Ethernet header */
-1);
cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* Ethernet */
cstate->off_nl = 0; /* Ethernet II */
cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
break;
case A_LLC:
/* Get all LLC-encapsulated packets */
if (!cstate->is_atm)
bpf_error(cstate, "'llc' supported only on raw ATM");
b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
cstate->linktype = cstate->prevlinktype;
break;
default:
abort();
}
return b1;
}
/*
* Filtering for MTP2 messages based on li value
* FISU, length is null
* LSSU, length is 1 or 2
* MSU, length is 3 or more
* For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits
*/
struct block *
gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
{
struct block *b0, *b1;
switch (type) {
case M_FISU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'fisu' supported only on MTP2");
/* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
break;
case M_LSSU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'lssu' supported only on MTP2");
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
gen_and(b1, b0);
break;
case M_MSU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'msu' supported only on MTP2");
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
break;
case MH_FISU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'hfisu' supported only on MTP2_HSL");
/* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JEQ, 0, 0);
break;
case MH_LSSU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'hlssu' supported only on MTP2_HSL");
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 1, 0x0100);
b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0);
gen_and(b1, b0);
break;
case MH_MSU:
if ( (cstate->linktype != DLT_MTP2) &&
(cstate->linktype != DLT_ERF) &&
(cstate->linktype != DLT_MTP2_WITH_PHDR) )
bpf_error(cstate, "'hmsu' supported only on MTP2_HSL");
b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0x0100);
break;
default:
abort();
}
return b0;
}
struct block *
gen_mtp3field_code(compiler_state_t *cstate, int mtp3field, bpf_u_int32 jvalue,
bpf_u_int32 jtype, int reverse)
{
struct block *b0;
bpf_u_int32 val1 , val2 , val3;
u_int newoff_sio = cstate->off_sio;
u_int newoff_opc = cstate->off_opc;
u_int newoff_dpc = cstate->off_dpc;
u_int newoff_sls = cstate->off_sls;
switch (mtp3field) {
case MH_SIO:
newoff_sio += 3; /* offset for MTP2_HSL */
/* FALLTHROUGH */
case M_SIO:
if (cstate->off_sio == OFFSET_NOT_SET)
bpf_error(cstate, "'sio' supported only on SS7");
/* sio coded on 1 byte so max value 255 */
if(jvalue > 255)
bpf_error(cstate, "sio value %u too big; max value = 255",
jvalue);
b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffff,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case MH_OPC:
newoff_opc+=3;
case M_OPC:
if (cstate->off_opc == OFFSET_NOT_SET)
bpf_error(cstate, "'opc' supported only on SS7");
/* opc coded on 14 bits so max value 16383 */
if (jvalue > 16383)
bpf_error(cstate, "opc value %u too big; max value = 16383",
jvalue);
/* the following instructions are made to convert jvalue
* to the form used to write opc in an ss7 message*/
val1 = jvalue & 0x00003c00;
val1 = val1 >>10;
val2 = jvalue & 0x000003fc;
val2 = val2 <<6;
val3 = jvalue & 0x00000003;
val3 = val3 <<22;
jvalue = val1 + val2 + val3;
b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0f,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case MH_DPC:
newoff_dpc += 3;
/* FALLTHROUGH */
case M_DPC:
if (cstate->off_dpc == OFFSET_NOT_SET)
bpf_error(cstate, "'dpc' supported only on SS7");
/* dpc coded on 14 bits so max value 16383 */
if (jvalue > 16383)
bpf_error(cstate, "dpc value %u too big; max value = 16383",
jvalue);
/* the following instructions are made to convert jvalue
* to the forme used to write dpc in an ss7 message*/
val1 = jvalue & 0x000000ff;
val1 = val1 << 24;
val2 = jvalue & 0x00003f00;
val2 = val2 << 8;
jvalue = val1 + val2;
b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case MH_SLS:
newoff_sls+=3;
case M_SLS:
if (cstate->off_sls == OFFSET_NOT_SET)
bpf_error(cstate, "'sls' supported only on SS7");
/* sls coded on 4 bits so max value 15 */
if (jvalue > 15)
bpf_error(cstate, "sls value %u too big; max value = 15",
jvalue);
/* the following instruction is made to convert jvalue
* to the forme used to write sls in an ss7 message*/
jvalue = jvalue << 4;
b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0,
(u_int)jtype,reverse, (u_int)jvalue);
break;
default:
abort();
}
return b0;
}
static struct block *
gen_msg_abbrev(compiler_state_t *cstate, int type)
{
struct block *b1;
/*
* Q.2931 signalling protocol messages for handling virtual circuits
* establishment and teardown
*/
switch (type) {
case A_SETUP:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
break;
case A_CALLPROCEED:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
break;
case A_CONNECT:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
break;
case A_CONNECTACK:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
break;
case A_RELEASE:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
break;
case A_RELEASE_DONE:
b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
break;
default:
abort();
}
return b1;
}
struct block *
gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
{
struct block *b0, *b1;
switch (type) {
case A_OAM:
if (!cstate->is_atm)
bpf_error(cstate, "'oam' supported only on raw ATM");
b1 = gen_atmmulti_abbrev(cstate, A_OAMF4);
break;
case A_OAMF4:
if (!cstate->is_atm)
bpf_error(cstate, "'oamf4' supported only on raw ATM");
/* OAM F4 type */
b0 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
gen_or(b0, b1);
b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_CONNECTMSG:
/*
* Get Q.2931 signalling messages for switched
* virtual connection
*/
if (!cstate->is_atm)
bpf_error(cstate, "'connectmsg' supported only on raw ATM");
b0 = gen_msg_abbrev(cstate, A_SETUP);
b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_CONNECT);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_RELEASE);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
gen_or(b0, b1);
b0 = gen_atmtype_abbrev(cstate, A_SC);
gen_and(b0, b1);
break;
case A_METACONNECT:
if (!cstate->is_atm)
bpf_error(cstate, "'metaconnect' supported only on raw ATM");
b0 = gen_msg_abbrev(cstate, A_SETUP);
b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_CONNECT);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_RELEASE);
gen_or(b0, b1);
b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
gen_or(b0, b1);
b0 = gen_atmtype_abbrev(cstate, A_METAC);
gen_and(b0, b1);
break;
default:
abort();
}
return b1;
}
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