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freebsd-skq/sys/netpfil/ipfw/ip_fw2.c
pfg d9c9113377 sys/net*: minor spelling fixes. 
No functional change.
2016-05-03 18:05:43 +00:00

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/*-
* Copyright (c) 2002-2009 Luigi Rizzo, Universita` di Pisa
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* The FreeBSD IP packet firewall, main file
*/
#include "opt_ipfw.h"
#include "opt_ipdivert.h"
#include "opt_inet.h"
#ifndef INET
#error "IPFIREWALL requires INET"
#endif /* INET */
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/condvar.h>
#include <sys/counter.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/jail.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/ucred.h>
#include <net/ethernet.h> /* for ETHERTYPE_IP */
#include <net/if.h>
#include <net/if_var.h>
#include <net/route.h>
#include <net/pfil.h>
#include <net/vnet.h>
#include <netpfil/pf/pf_mtag.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_pcb.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_carp.h>
#include <netinet/pim.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/sctp.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet/in_fib.h>
#ifdef INET6
#include <netinet6/in6_fib.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/scope6_var.h>
#include <netinet6/ip6_var.h>
#endif
#include <netpfil/ipfw/ip_fw_private.h>
#include <machine/in_cksum.h> /* XXX for in_cksum */
#ifdef MAC
#include <security/mac/mac_framework.h>
#endif
/*
* static variables followed by global ones.
* All ipfw global variables are here.
*/
static VNET_DEFINE(int, fw_deny_unknown_exthdrs);
#define V_fw_deny_unknown_exthdrs VNET(fw_deny_unknown_exthdrs)
static VNET_DEFINE(int, fw_permit_single_frag6) = 1;
#define V_fw_permit_single_frag6 VNET(fw_permit_single_frag6)
#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
static int default_to_accept = 1;
#else
static int default_to_accept;
#endif
VNET_DEFINE(int, autoinc_step);
VNET_DEFINE(int, fw_one_pass) = 1;
VNET_DEFINE(unsigned int, fw_tables_max);
VNET_DEFINE(unsigned int, fw_tables_sets) = 0; /* Don't use set-aware tables */
/* Use 128 tables by default */
static unsigned int default_fw_tables = IPFW_TABLES_DEFAULT;
#ifndef LINEAR_SKIPTO
static int jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num,
int tablearg, int jump_backwards);
#define JUMP(ch, f, num, targ, back) jump_fast(ch, f, num, targ, back)
#else
static int jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num,
int tablearg, int jump_backwards);
#define JUMP(ch, f, num, targ, back) jump_linear(ch, f, num, targ, back)
#endif
/*
* Each rule belongs to one of 32 different sets (0..31).
* The variable set_disable contains one bit per set.
* If the bit is set, all rules in the corresponding set
* are disabled. Set RESVD_SET(31) is reserved for the default rule
* and rules that are not deleted by the flush command,
* and CANNOT be disabled.
* Rules in set RESVD_SET can only be deleted individually.
*/
VNET_DEFINE(u_int32_t, set_disable);
#define V_set_disable VNET(set_disable)
VNET_DEFINE(int, fw_verbose);
/* counter for ipfw_log(NULL...) */
VNET_DEFINE(u_int64_t, norule_counter);
VNET_DEFINE(int, verbose_limit);
/* layer3_chain contains the list of rules for layer 3 */
VNET_DEFINE(struct ip_fw_chain, layer3_chain);
/* ipfw_vnet_ready controls when we are open for business */
VNET_DEFINE(int, ipfw_vnet_ready) = 0;
VNET_DEFINE(int, ipfw_nat_ready) = 0;
ipfw_nat_t *ipfw_nat_ptr = NULL;
struct cfg_nat *(*lookup_nat_ptr)(struct nat_list *, int);
ipfw_nat_cfg_t *ipfw_nat_cfg_ptr;
ipfw_nat_cfg_t *ipfw_nat_del_ptr;
ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr;
ipfw_nat_cfg_t *ipfw_nat_get_log_ptr;
#ifdef SYSCTL_NODE
uint32_t dummy_def = IPFW_DEFAULT_RULE;
static int sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS);
static int sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS);
SYSBEGIN(f3)
SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass,
CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_one_pass), 0,
"Only do a single pass through ipfw when using dummynet(4)");
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(autoinc_step), 0,
"Rule number auto-increment step");
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose,
CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_verbose), 0,
"Log matches to ipfw rules");
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(verbose_limit), 0,
"Set upper limit of matches of ipfw rules logged");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, default_rule, CTLFLAG_RD,
&dummy_def, 0,
"The default/max possible rule number.");
SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_max,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_table_num, "IU",
"Maximum number of concurrently used tables");
SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_sets,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW,
0, 0, sysctl_ipfw_tables_sets, "IU",
"Use per-set namespace for tables");
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, default_to_accept, CTLFLAG_RDTUN,
&default_to_accept, 0,
"Make the default rule accept all packets.");
TUNABLE_INT("net.inet.ip.fw.tables_max", (int *)&default_fw_tables);
SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count,
CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(layer3_chain.n_rules), 0,
"Number of static rules");
#ifdef INET6
SYSCTL_DECL(_net_inet6_ip6);
SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, deny_unknown_exthdrs,
CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE,
&VNET_NAME(fw_deny_unknown_exthdrs), 0,
"Deny packets with unknown IPv6 Extension Headers");
SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, permit_single_frag6,
CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE,
&VNET_NAME(fw_permit_single_frag6), 0,
"Permit single packet IPv6 fragments");
#endif /* INET6 */
SYSEND
#endif /* SYSCTL_NODE */
/*
* Some macros used in the various matching options.
* L3HDR maps an ipv4 pointer into a layer3 header pointer of type T
* Other macros just cast void * into the appropriate type
*/
#define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl))
#define TCP(p) ((struct tcphdr *)(p))
#define SCTP(p) ((struct sctphdr *)(p))
#define UDP(p) ((struct udphdr *)(p))
#define ICMP(p) ((struct icmphdr *)(p))
#define ICMP6(p) ((struct icmp6_hdr *)(p))
static __inline int
icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd)
{
int type = icmp->icmp_type;
return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) );
}
#define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \
(1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) )
static int
is_icmp_query(struct icmphdr *icmp)
{
int type = icmp->icmp_type;
return (type <= ICMP_MAXTYPE && (TT & (1<<type)) );
}
#undef TT
/*
* The following checks use two arrays of 8 or 16 bits to store the
* bits that we want set or clear, respectively. They are in the
* low and high half of cmd->arg1 or cmd->d[0].
*
* We scan options and store the bits we find set. We succeed if
*
* (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear
*
* The code is sometimes optimized not to store additional variables.
*/
static int
flags_match(ipfw_insn *cmd, u_int8_t bits)
{
u_char want_clear;
bits = ~bits;
if ( ((cmd->arg1 & 0xff) & bits) != 0)
return 0; /* some bits we want set were clear */
want_clear = (cmd->arg1 >> 8) & 0xff;
if ( (want_clear & bits) != want_clear)
return 0; /* some bits we want clear were set */
return 1;
}
static int
ipopts_match(struct ip *ip, ipfw_insn *cmd)
{
int optlen, bits = 0;
u_char *cp = (u_char *)(ip + 1);
int x = (ip->ip_hl << 2) - sizeof (struct ip);
for (; x > 0; x -= optlen, cp += optlen) {
int opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else {
optlen = cp[IPOPT_OLEN];
if (optlen <= 0 || optlen > x)
return 0; /* invalid or truncated */
}
switch (opt) {
default:
break;
case IPOPT_LSRR:
bits |= IP_FW_IPOPT_LSRR;
break;
case IPOPT_SSRR:
bits |= IP_FW_IPOPT_SSRR;
break;
case IPOPT_RR:
bits |= IP_FW_IPOPT_RR;
break;
case IPOPT_TS:
bits |= IP_FW_IPOPT_TS;
break;
}
}
return (flags_match(cmd, bits));
}
static int
tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd)
{
int optlen, bits = 0;
u_char *cp = (u_char *)(tcp + 1);
int x = (tcp->th_off << 2) - sizeof(struct tcphdr);
for (; x > 0; x -= optlen, cp += optlen) {
int opt = cp[0];
if (opt == TCPOPT_EOL)
break;
if (opt == TCPOPT_NOP)
optlen = 1;
else {
optlen = cp[1];
if (optlen <= 0)
break;
}
switch (opt) {
default:
break;
case TCPOPT_MAXSEG:
bits |= IP_FW_TCPOPT_MSS;
break;
case TCPOPT_WINDOW:
bits |= IP_FW_TCPOPT_WINDOW;
break;
case TCPOPT_SACK_PERMITTED:
case TCPOPT_SACK:
bits |= IP_FW_TCPOPT_SACK;
break;
case TCPOPT_TIMESTAMP:
bits |= IP_FW_TCPOPT_TS;
break;
}
}
return (flags_match(cmd, bits));
}
static int
iface_match(struct ifnet *ifp, ipfw_insn_if *cmd, struct ip_fw_chain *chain,
uint32_t *tablearg)
{
if (ifp == NULL) /* no iface with this packet, match fails */
return (0);
/* Check by name or by IP address */
if (cmd->name[0] != '\0') { /* match by name */
if (cmd->name[0] == '\1') /* use tablearg to match */
return ipfw_lookup_table_extended(chain, cmd->p.kidx, 0,
&ifp->if_index, tablearg);
/* Check name */
if (cmd->p.glob) {
if (fnmatch(cmd->name, ifp->if_xname, 0) == 0)
return(1);
} else {
if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0)
return(1);
}
} else {
#if !defined(USERSPACE) && defined(__FreeBSD__) /* and OSX too ? */
struct ifaddr *ia;
if_addr_rlock(ifp);
TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
if (ia->ifa_addr->sa_family != AF_INET)
continue;
if (cmd->p.ip.s_addr == ((struct sockaddr_in *)
(ia->ifa_addr))->sin_addr.s_addr) {
if_addr_runlock(ifp);
return(1); /* match */
}
}
if_addr_runlock(ifp);
#endif /* __FreeBSD__ */
}
return(0); /* no match, fail ... */
}
/*
* The verify_path function checks if a route to the src exists and
* if it is reachable via ifp (when provided).
*
* The 'verrevpath' option checks that the interface that an IP packet
* arrives on is the same interface that traffic destined for the
* packet's source address would be routed out of.
* The 'versrcreach' option just checks that the source address is
* reachable via any route (except default) in the routing table.
* These two are a measure to block forged packets. This is also
* commonly known as "anti-spoofing" or Unicast Reverse Path
* Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs
* is purposely reminiscent of the Cisco IOS command,
*
* ip verify unicast reverse-path
* ip verify unicast source reachable-via any
*
* which implements the same functionality. But note that the syntax
* is misleading, and the check may be performed on all IP packets
* whether unicast, multicast, or broadcast.
*/
static int
verify_path(struct in_addr src, struct ifnet *ifp, u_int fib)
{
#if defined(USERSPACE) || !defined(__FreeBSD__)
return 0;
#else
struct nhop4_basic nh4;
if (fib4_lookup_nh_basic(fib, src, NHR_IFAIF, 0, &nh4) != 0)
return (0);
/*
* If ifp is provided, check for equality with rtentry.
* We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp,
* in order to pass packets injected back by if_simloop():
* routing entry (via lo0) for our own address
* may exist, so we need to handle routing assymetry.
*/
if (ifp != NULL && ifp != nh4.nh_ifp)
return (0);
/* if no ifp provided, check if rtentry is not default route */
if (ifp == NULL && (nh4.nh_flags & NHF_DEFAULT) != 0)
return (0);
/* or if this is a blackhole/reject route */
if (ifp == NULL && (nh4.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0)
return (0);
/* found valid route */
return 1;
#endif /* __FreeBSD__ */
}
#ifdef INET6
/*
* ipv6 specific rules here...
*/
static __inline int
icmp6type_match (int type, ipfw_insn_u32 *cmd)
{
return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) );
}
static int
flow6id_match( int curr_flow, ipfw_insn_u32 *cmd )
{
int i;
for (i=0; i <= cmd->o.arg1; ++i )
if (curr_flow == cmd->d[i] )
return 1;
return 0;
}
/* support for IP6_*_ME opcodes */
static const struct in6_addr lla_mask = {{{
0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
}}};
static int
ipfw_localip6(struct in6_addr *in6)
{
struct rm_priotracker in6_ifa_tracker;
struct in6_ifaddr *ia;
if (IN6_IS_ADDR_MULTICAST(in6))
return (0);
if (!IN6_IS_ADDR_LINKLOCAL(in6))
return (in6_localip(in6));
IN6_IFADDR_RLOCK(&in6_ifa_tracker);
TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
if (!IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr))
continue;
if (IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
in6, &lla_mask)) {
IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
return (1);
}
}
IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
return (0);
}
static int
verify_path6(struct in6_addr *src, struct ifnet *ifp, u_int fib)
{
struct nhop6_basic nh6;
if (IN6_IS_SCOPE_LINKLOCAL(src))
return (1);
if (fib6_lookup_nh_basic(fib, src, 0, NHR_IFAIF, 0, &nh6) != 0)
return (0);
/* If ifp is provided, check for equality with route table. */
if (ifp != NULL && ifp != nh6.nh_ifp)
return (0);
/* if no ifp provided, check if rtentry is not default route */
if (ifp == NULL && (nh6.nh_flags & NHF_DEFAULT) != 0)
return (0);
/* or if this is a blackhole/reject route */
if (ifp == NULL && (nh6.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0)
return (0);
/* found valid route */
return 1;
}
static int
is_icmp6_query(int icmp6_type)
{
if ((icmp6_type <= ICMP6_MAXTYPE) &&
(icmp6_type == ICMP6_ECHO_REQUEST ||
icmp6_type == ICMP6_MEMBERSHIP_QUERY ||
icmp6_type == ICMP6_WRUREQUEST ||
icmp6_type == ICMP6_FQDN_QUERY ||
icmp6_type == ICMP6_NI_QUERY))
return (1);
return (0);
}
static void
send_reject6(struct ip_fw_args *args, int code, u_int hlen, struct ip6_hdr *ip6)
{
struct mbuf *m;
m = args->m;
if (code == ICMP6_UNREACH_RST && args->f_id.proto == IPPROTO_TCP) {
struct tcphdr *tcp;
tcp = (struct tcphdr *)((char *)ip6 + hlen);
if ((tcp->th_flags & TH_RST) == 0) {
struct mbuf *m0;
m0 = ipfw_send_pkt(args->m, &(args->f_id),
ntohl(tcp->th_seq), ntohl(tcp->th_ack),
tcp->th_flags | TH_RST);
if (m0 != NULL)
ip6_output(m0, NULL, NULL, 0, NULL, NULL,
NULL);
}
FREE_PKT(m);
} else if (code != ICMP6_UNREACH_RST) { /* Send an ICMPv6 unreach. */
#if 0
/*
* Unlike above, the mbufs need to line up with the ip6 hdr,
* as the contents are read. We need to m_adj() the
* needed amount.
* The mbuf will however be thrown away so we can adjust it.
* Remember we did an m_pullup on it already so we
* can make some assumptions about contiguousness.
*/
if (args->L3offset)
m_adj(m, args->L3offset);
#endif
icmp6_error(m, ICMP6_DST_UNREACH, code, 0);
} else
FREE_PKT(m);
args->m = NULL;
}
#endif /* INET6 */
/*
* sends a reject message, consuming the mbuf passed as an argument.
*/
static void
send_reject(struct ip_fw_args *args, int code, int iplen, struct ip *ip)
{
#if 0
/* XXX When ip is not guaranteed to be at mtod() we will
* need to account for this */
* The mbuf will however be thrown away so we can adjust it.
* Remember we did an m_pullup on it already so we
* can make some assumptions about contiguousness.
*/
if (args->L3offset)
m_adj(m, args->L3offset);
#endif
if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */
icmp_error(args->m, ICMP_UNREACH, code, 0L, 0);
} else if (args->f_id.proto == IPPROTO_TCP) {
struct tcphdr *const tcp =
L3HDR(struct tcphdr, mtod(args->m, struct ip *));
if ( (tcp->th_flags & TH_RST) == 0) {
struct mbuf *m;
m = ipfw_send_pkt(args->m, &(args->f_id),
ntohl(tcp->th_seq), ntohl(tcp->th_ack),
tcp->th_flags | TH_RST);
if (m != NULL)
ip_output(m, NULL, NULL, 0, NULL, NULL);
}
FREE_PKT(args->m);
} else
FREE_PKT(args->m);
args->m = NULL;
}
/*
* Support for uid/gid/jail lookup. These tests are expensive
* (because we may need to look into the list of active sockets)
* so we cache the results. ugid_lookupp is 0 if we have not
* yet done a lookup, 1 if we succeeded, and -1 if we tried
* and failed. The function always returns the match value.
* We could actually spare the variable and use *uc, setting
* it to '(void *)check_uidgid if we have no info, NULL if
* we tried and failed, or any other value if successful.
*/
static int
check_uidgid(ipfw_insn_u32 *insn, struct ip_fw_args *args, int *ugid_lookupp,
struct ucred **uc)
{
#if defined(USERSPACE)
return 0; // not supported in userspace
#else
#ifndef __FreeBSD__
/* XXX */
return cred_check(insn, proto, oif,
dst_ip, dst_port, src_ip, src_port,
(struct bsd_ucred *)uc, ugid_lookupp, ((struct mbuf *)inp)->m_skb);
#else /* FreeBSD */
struct in_addr src_ip, dst_ip;
struct inpcbinfo *pi;
struct ipfw_flow_id *id;
struct inpcb *pcb, *inp;
struct ifnet *oif;
int lookupflags;
int match;
id = &args->f_id;
inp = args->inp;
oif = args->oif;
/*
* Check to see if the UDP or TCP stack supplied us with
* the PCB. If so, rather then holding a lock and looking
* up the PCB, we can use the one that was supplied.
*/
if (inp && *ugid_lookupp == 0) {
INP_LOCK_ASSERT(inp);
if (inp->inp_socket != NULL) {
*uc = crhold(inp->inp_cred);
*ugid_lookupp = 1;
} else
*ugid_lookupp = -1;
}
/*
* If we have already been here and the packet has no
* PCB entry associated with it, then we can safely
* assume that this is a no match.
*/
if (*ugid_lookupp == -1)
return (0);
if (id->proto == IPPROTO_TCP) {
lookupflags = 0;
pi = &V_tcbinfo;
} else if (id->proto == IPPROTO_UDP) {
lookupflags = INPLOOKUP_WILDCARD;
pi = &V_udbinfo;
} else
return 0;
lookupflags |= INPLOOKUP_RLOCKPCB;
match = 0;
if (*ugid_lookupp == 0) {
if (id->addr_type == 6) {
#ifdef INET6
if (oif == NULL)
pcb = in6_pcblookup_mbuf(pi,
&id->src_ip6, htons(id->src_port),
&id->dst_ip6, htons(id->dst_port),
lookupflags, oif, args->m);
else
pcb = in6_pcblookup_mbuf(pi,
&id->dst_ip6, htons(id->dst_port),
&id->src_ip6, htons(id->src_port),
lookupflags, oif, args->m);
#else
*ugid_lookupp = -1;
return (0);
#endif
} else {
src_ip.s_addr = htonl(id->src_ip);
dst_ip.s_addr = htonl(id->dst_ip);
if (oif == NULL)
pcb = in_pcblookup_mbuf(pi,
src_ip, htons(id->src_port),
dst_ip, htons(id->dst_port),
lookupflags, oif, args->m);
else
pcb = in_pcblookup_mbuf(pi,
dst_ip, htons(id->dst_port),
src_ip, htons(id->src_port),
lookupflags, oif, args->m);
}
if (pcb != NULL) {
INP_RLOCK_ASSERT(pcb);
*uc = crhold(pcb->inp_cred);
*ugid_lookupp = 1;
INP_RUNLOCK(pcb);
}
if (*ugid_lookupp == 0) {
/*
* We tried and failed, set the variable to -1
* so we will not try again on this packet.
*/
*ugid_lookupp = -1;
return (0);
}
}
if (insn->o.opcode == O_UID)
match = ((*uc)->cr_uid == (uid_t)insn->d[0]);
else if (insn->o.opcode == O_GID)
match = groupmember((gid_t)insn->d[0], *uc);
else if (insn->o.opcode == O_JAIL)
match = ((*uc)->cr_prison->pr_id == (int)insn->d[0]);
return (match);
#endif /* __FreeBSD__ */
#endif /* not supported in userspace */
}
/*
* Helper function to set args with info on the rule after the matching
* one. slot is precise, whereas we guess rule_id as they are
* assigned sequentially.
*/
static inline void
set_match(struct ip_fw_args *args, int slot,
struct ip_fw_chain *chain)
{
args->rule.chain_id = chain->id;
args->rule.slot = slot + 1; /* we use 0 as a marker */
args->rule.rule_id = 1 + chain->map[slot]->id;
args->rule.rulenum = chain->map[slot]->rulenum;
}
#ifndef LINEAR_SKIPTO
/*
* Helper function to enable cached rule lookups using
* cached_id and cached_pos fields in ipfw rule.
*/
static int
jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num,
int tablearg, int jump_backwards)
{
int f_pos;
/* If possible use cached f_pos (in f->cached_pos),
* whose version is written in f->cached_id
* (horrible hacks to avoid changing the ABI).
*/
if (num != IP_FW_TARG && f->cached_id == chain->id)
f_pos = f->cached_pos;
else {
int i = IP_FW_ARG_TABLEARG(chain, num, skipto);
/* make sure we do not jump backward */
if (jump_backwards == 0 && i <= f->rulenum)
i = f->rulenum + 1;
if (chain->idxmap != NULL)
f_pos = chain->idxmap[i];
else
f_pos = ipfw_find_rule(chain, i, 0);
/* update the cache */
if (num != IP_FW_TARG) {
f->cached_id = chain->id;
f->cached_pos = f_pos;
}
}
return (f_pos);
}
#else
/*
* Helper function to enable real fast rule lookups.
*/
static int
jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num,
int tablearg, int jump_backwards)
{
int f_pos;
num = IP_FW_ARG_TABLEARG(chain, num, skipto);
/* make sure we do not jump backward */
if (jump_backwards == 0 && num <= f->rulenum)
num = f->rulenum + 1;
f_pos = chain->idxmap[num];
return (f_pos);
}
#endif
#define TARG(k, f) IP_FW_ARG_TABLEARG(chain, k, f)
/*
* The main check routine for the firewall.
*
* All arguments are in args so we can modify them and return them
* back to the caller.
*
* Parameters:
*
* args->m (in/out) The packet; we set to NULL when/if we nuke it.
* Starts with the IP header.
* args->eh (in) Mac header if present, NULL for layer3 packet.
* args->L3offset Number of bytes bypassed if we came from L2.
* e.g. often sizeof(eh) ** NOTYET **
* args->oif Outgoing interface, NULL if packet is incoming.
* The incoming interface is in the mbuf. (in)
* args->divert_rule (in/out)
* Skip up to the first rule past this rule number;
* upon return, non-zero port number for divert or tee.
*
* args->rule Pointer to the last matching rule (in/out)
* args->next_hop Socket we are forwarding to (out).
* args->next_hop6 IPv6 next hop we are forwarding to (out).
* args->f_id Addresses grabbed from the packet (out)
* args->rule.info a cookie depending on rule action
*
* Return value:
*
* IP_FW_PASS the packet must be accepted
* IP_FW_DENY the packet must be dropped
* IP_FW_DIVERT divert packet, port in m_tag
* IP_FW_TEE tee packet, port in m_tag
* IP_FW_DUMMYNET to dummynet, pipe in args->cookie
* IP_FW_NETGRAPH into netgraph, cookie args->cookie
* args->rule contains the matching rule,
* args->rule.info has additional information.
*
*/
int
ipfw_chk(struct ip_fw_args *args)
{
/*
* Local variables holding state while processing a packet:
*
* IMPORTANT NOTE: to speed up the processing of rules, there
* are some assumption on the values of the variables, which
* are documented here. Should you change them, please check
* the implementation of the various instructions to make sure
* that they still work.
*
* args->eh The MAC header. It is non-null for a layer2
* packet, it is NULL for a layer-3 packet.
* **notyet**
* args->L3offset Offset in the packet to the L3 (IP or equiv.) header.
*
* m | args->m Pointer to the mbuf, as received from the caller.
* It may change if ipfw_chk() does an m_pullup, or if it
* consumes the packet because it calls send_reject().
* XXX This has to change, so that ipfw_chk() never modifies
* or consumes the buffer.
* ip is the beginning of the ip(4 or 6) header.
* Calculated by adding the L3offset to the start of data.
* (Until we start using L3offset, the packet is
* supposed to start with the ip header).
*/
struct mbuf *m = args->m;
struct ip *ip = mtod(m, struct ip *);
/*
* For rules which contain uid/gid or jail constraints, cache
* a copy of the users credentials after the pcb lookup has been
* executed. This will speed up the processing of rules with
* these types of constraints, as well as decrease contention
* on pcb related locks.
*/
#ifndef __FreeBSD__
struct bsd_ucred ucred_cache;
#else
struct ucred *ucred_cache = NULL;
#endif
int ucred_lookup = 0;
/*
* oif | args->oif If NULL, ipfw_chk has been called on the
* inbound path (ether_input, ip_input).
* If non-NULL, ipfw_chk has been called on the outbound path
* (ether_output, ip_output).
*/
struct ifnet *oif = args->oif;
int f_pos = 0; /* index of current rule in the array */
int retval = 0;
/*
* hlen The length of the IP header.
*/
u_int hlen = 0; /* hlen >0 means we have an IP pkt */
/*
* offset The offset of a fragment. offset != 0 means that
* we have a fragment at this offset of an IPv4 packet.
* offset == 0 means that (if this is an IPv4 packet)
* this is the first or only fragment.
* For IPv6 offset|ip6f_mf == 0 means there is no Fragment Header
* or there is a single packet fragment (fragment header added
* without needed). We will treat a single packet fragment as if
* there was no fragment header (or log/block depending on the
* V_fw_permit_single_frag6 sysctl setting).
*/
u_short offset = 0;
u_short ip6f_mf = 0;
/*
* Local copies of addresses. They are only valid if we have
* an IP packet.
*
* proto The protocol. Set to 0 for non-ip packets,
* or to the protocol read from the packet otherwise.
* proto != 0 means that we have an IPv4 packet.
*
* src_port, dst_port port numbers, in HOST format. Only
* valid for TCP and UDP packets.
*
* src_ip, dst_ip ip addresses, in NETWORK format.
* Only valid for IPv4 packets.
*/
uint8_t proto;
uint16_t src_port = 0, dst_port = 0; /* NOTE: host format */
struct in_addr src_ip, dst_ip; /* NOTE: network format */
uint16_t iplen=0;
int pktlen;
uint16_t etype = 0; /* Host order stored ether type */
/*
* dyn_dir = MATCH_UNKNOWN when rules unchecked,
* MATCH_NONE when checked and not matched (q = NULL),
* MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL)
*/
int dyn_dir = MATCH_UNKNOWN;
ipfw_dyn_rule *q = NULL;
struct ip_fw_chain *chain = &V_layer3_chain;
/*
* We store in ulp a pointer to the upper layer protocol header.
* In the ipv4 case this is easy to determine from the header,
* but for ipv6 we might have some additional headers in the middle.
* ulp is NULL if not found.
*/
void *ulp = NULL; /* upper layer protocol pointer. */
/* XXX ipv6 variables */
int is_ipv6 = 0;
uint8_t icmp6_type = 0;
uint16_t ext_hd = 0; /* bits vector for extension header filtering */
/* end of ipv6 variables */
int is_ipv4 = 0;
int done = 0; /* flag to exit the outer loop */
IPFW_RLOCK_TRACKER;
if (m->m_flags & M_SKIP_FIREWALL || (! V_ipfw_vnet_ready))
return (IP_FW_PASS); /* accept */
dst_ip.s_addr = 0; /* make sure it is initialized */
src_ip.s_addr = 0; /* make sure it is initialized */
pktlen = m->m_pkthdr.len;
args->f_id.fib = M_GETFIB(m); /* note mbuf not altered) */
proto = args->f_id.proto = 0; /* mark f_id invalid */
/* XXX 0 is a valid proto: IP/IPv6 Hop-by-Hop Option */
/*
* PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous,
* then it sets p to point at the offset "len" in the mbuf. WARNING: the
* pointer might become stale after other pullups (but we never use it
* this way).
*/
#define PULLUP_TO(_len, p, T) PULLUP_LEN(_len, p, sizeof(T))
#define PULLUP_LEN(_len, p, T) \
do { \
int x = (_len) + T; \
if ((m)->m_len < x) { \
args->m = m = m_pullup(m, x); \
if (m == NULL) \
goto pullup_failed; \
} \
p = (mtod(m, char *) + (_len)); \
} while (0)
/*
* if we have an ether header,
*/
if (args->eh)
etype = ntohs(args->eh->ether_type);
/* Identify IP packets and fill up variables. */
if (pktlen >= sizeof(struct ip6_hdr) &&
(args->eh == NULL || etype == ETHERTYPE_IPV6) && ip->ip_v == 6) {
struct ip6_hdr *ip6 = (struct ip6_hdr *)ip;
is_ipv6 = 1;
args->f_id.addr_type = 6;
hlen = sizeof(struct ip6_hdr);
proto = ip6->ip6_nxt;
/* Search extension headers to find upper layer protocols */
while (ulp == NULL && offset == 0) {
switch (proto) {
case IPPROTO_ICMPV6:
PULLUP_TO(hlen, ulp, struct icmp6_hdr);
icmp6_type = ICMP6(ulp)->icmp6_type;
break;
case IPPROTO_TCP:
PULLUP_TO(hlen, ulp, struct tcphdr);
dst_port = TCP(ulp)->th_dport;
src_port = TCP(ulp)->th_sport;
/* save flags for dynamic rules */
args->f_id._flags = TCP(ulp)->th_flags;
break;
case IPPROTO_SCTP:
PULLUP_TO(hlen, ulp, struct sctphdr);
src_port = SCTP(ulp)->src_port;
dst_port = SCTP(ulp)->dest_port;
break;
case IPPROTO_UDP:
PULLUP_TO(hlen, ulp, struct udphdr);
dst_port = UDP(ulp)->uh_dport;
src_port = UDP(ulp)->uh_sport;
break;
case IPPROTO_HOPOPTS: /* RFC 2460 */
PULLUP_TO(hlen, ulp, struct ip6_hbh);
ext_hd |= EXT_HOPOPTS;
hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3;
proto = ((struct ip6_hbh *)ulp)->ip6h_nxt;
ulp = NULL;
break;
case IPPROTO_ROUTING: /* RFC 2460 */
PULLUP_TO(hlen, ulp, struct ip6_rthdr);
switch (((struct ip6_rthdr *)ulp)->ip6r_type) {
case 0:
ext_hd |= EXT_RTHDR0;
break;
case 2:
ext_hd |= EXT_RTHDR2;
break;
default:
if (V_fw_verbose)
printf("IPFW2: IPV6 - Unknown "
"Routing Header type(%d)\n",
((struct ip6_rthdr *)
ulp)->ip6r_type);
if (V_fw_deny_unknown_exthdrs)
return (IP_FW_DENY);
break;
}
ext_hd |= EXT_ROUTING;
hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3;
proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt;
ulp = NULL;
break;
case IPPROTO_FRAGMENT: /* RFC 2460 */
PULLUP_TO(hlen, ulp, struct ip6_frag);
ext_hd |= EXT_FRAGMENT;
hlen += sizeof (struct ip6_frag);
proto = ((struct ip6_frag *)ulp)->ip6f_nxt;
offset = ((struct ip6_frag *)ulp)->ip6f_offlg &
IP6F_OFF_MASK;
ip6f_mf = ((struct ip6_frag *)ulp)->ip6f_offlg &
IP6F_MORE_FRAG;
if (V_fw_permit_single_frag6 == 0 &&
offset == 0 && ip6f_mf == 0) {
if (V_fw_verbose)
printf("IPFW2: IPV6 - Invalid "
"Fragment Header\n");
if (V_fw_deny_unknown_exthdrs)
return (IP_FW_DENY);
break;
}
args->f_id.extra =
ntohl(((struct ip6_frag *)ulp)->ip6f_ident);
ulp = NULL;
break;
case IPPROTO_DSTOPTS: /* RFC 2460 */
PULLUP_TO(hlen, ulp, struct ip6_hbh);
ext_hd |= EXT_DSTOPTS;
hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3;
proto = ((struct ip6_hbh *)ulp)->ip6h_nxt;
ulp = NULL;
break;
case IPPROTO_AH: /* RFC 2402 */
PULLUP_TO(hlen, ulp, struct ip6_ext);
ext_hd |= EXT_AH;
hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2;
proto = ((struct ip6_ext *)ulp)->ip6e_nxt;
ulp = NULL;
break;
case IPPROTO_ESP: /* RFC 2406 */
PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */
/* Anything past Seq# is variable length and
* data past this ext. header is encrypted. */
ext_hd |= EXT_ESP;
break;
case IPPROTO_NONE: /* RFC 2460 */
/*
* Packet ends here, and IPv6 header has
* already been pulled up. If ip6e_len!=0
* then octets must be ignored.
*/
ulp = ip; /* non-NULL to get out of loop. */
break;
case IPPROTO_OSPFIGP:
/* XXX OSPF header check? */
PULLUP_TO(hlen, ulp, struct ip6_ext);
break;
case IPPROTO_PIM:
/* XXX PIM header check? */
PULLUP_TO(hlen, ulp, struct pim);
break;
case IPPROTO_CARP:
PULLUP_TO(hlen, ulp, struct carp_header);
if (((struct carp_header *)ulp)->carp_version !=
CARP_VERSION)
return (IP_FW_DENY);
if (((struct carp_header *)ulp)->carp_type !=
CARP_ADVERTISEMENT)
return (IP_FW_DENY);
break;
case IPPROTO_IPV6: /* RFC 2893 */
PULLUP_TO(hlen, ulp, struct ip6_hdr);
break;
case IPPROTO_IPV4: /* RFC 2893 */
PULLUP_TO(hlen, ulp, struct ip);
break;
default:
if (V_fw_verbose)
printf("IPFW2: IPV6 - Unknown "
"Extension Header(%d), ext_hd=%x\n",
proto, ext_hd);
if (V_fw_deny_unknown_exthdrs)
return (IP_FW_DENY);
PULLUP_TO(hlen, ulp, struct ip6_ext);
break;
} /*switch */
}
ip = mtod(m, struct ip *);
ip6 = (struct ip6_hdr *)ip;
args->f_id.src_ip6 = ip6->ip6_src;
args->f_id.dst_ip6 = ip6->ip6_dst;
args->f_id.src_ip = 0;
args->f_id.dst_ip = 0;
args->f_id.flow_id6 = ntohl(ip6->ip6_flow);
} else if (pktlen >= sizeof(struct ip) &&
(args->eh == NULL || etype == ETHERTYPE_IP) && ip->ip_v == 4) {
is_ipv4 = 1;
hlen = ip->ip_hl << 2;
args->f_id.addr_type = 4;
/*
* Collect parameters into local variables for faster matching.
*/
proto = ip->ip_p;
src_ip = ip->ip_src;
dst_ip = ip->ip_dst;
offset = ntohs(ip->ip_off) & IP_OFFMASK;
iplen = ntohs(ip->ip_len);
pktlen = iplen < pktlen ? iplen : pktlen;
if (offset == 0) {
switch (proto) {
case IPPROTO_TCP:
PULLUP_TO(hlen, ulp, struct tcphdr);
dst_port = TCP(ulp)->th_dport;
src_port = TCP(ulp)->th_sport;
/* save flags for dynamic rules */
args->f_id._flags = TCP(ulp)->th_flags;
break;
case IPPROTO_SCTP:
PULLUP_TO(hlen, ulp, struct sctphdr);
src_port = SCTP(ulp)->src_port;
dst_port = SCTP(ulp)->dest_port;
break;
case IPPROTO_UDP:
PULLUP_TO(hlen, ulp, struct udphdr);
dst_port = UDP(ulp)->uh_dport;
src_port = UDP(ulp)->uh_sport;
break;
case IPPROTO_ICMP:
PULLUP_TO(hlen, ulp, struct icmphdr);
//args->f_id.flags = ICMP(ulp)->icmp_type;
break;
default:
break;
}
}
ip = mtod(m, struct ip *);
args->f_id.src_ip = ntohl(src_ip.s_addr);
args->f_id.dst_ip = ntohl(dst_ip.s_addr);
}
#undef PULLUP_TO
if (proto) { /* we may have port numbers, store them */
args->f_id.proto = proto;
args->f_id.src_port = src_port = ntohs(src_port);
args->f_id.dst_port = dst_port = ntohs(dst_port);
}
IPFW_PF_RLOCK(chain);
if (! V_ipfw_vnet_ready) { /* shutting down, leave NOW. */
IPFW_PF_RUNLOCK(chain);
return (IP_FW_PASS); /* accept */
}
if (args->rule.slot) {
/*
* Packet has already been tagged as a result of a previous
* match on rule args->rule aka args->rule_id (PIPE, QUEUE,
* REASS, NETGRAPH, DIVERT/TEE...)
* Validate the slot and continue from the next one
* if still present, otherwise do a lookup.
*/
f_pos = (args->rule.chain_id == chain->id) ?
args->rule.slot :
ipfw_find_rule(chain, args->rule.rulenum,
args->rule.rule_id);
} else {
f_pos = 0;
}
/*
* Now scan the rules, and parse microinstructions for each rule.
* We have two nested loops and an inner switch. Sometimes we
* need to break out of one or both loops, or re-enter one of
* the loops with updated variables. Loop variables are:
*
* f_pos (outer loop) points to the current rule.
* On output it points to the matching rule.
* done (outer loop) is used as a flag to break the loop.
* l (inner loop) residual length of current rule.
* cmd points to the current microinstruction.
*
* We break the inner loop by setting l=0 and possibly
* cmdlen=0 if we don't want to advance cmd.
* We break the outer loop by setting done=1
* We can restart the inner loop by setting l>0 and f_pos, f, cmd
* as needed.
*/
for (; f_pos < chain->n_rules; f_pos++) {
ipfw_insn *cmd;
uint32_t tablearg = 0;
int l, cmdlen, skip_or; /* skip rest of OR block */
struct ip_fw *f;
f = chain->map[f_pos];
if (V_set_disable & (1 << f->set) )
continue;
skip_or = 0;
for (l = f->cmd_len, cmd = f->cmd ; l > 0 ;
l -= cmdlen, cmd += cmdlen) {
int match;
/*
* check_body is a jump target used when we find a
* CHECK_STATE, and need to jump to the body of
* the target rule.
*/
/* check_body: */
cmdlen = F_LEN(cmd);
/*
* An OR block (insn_1 || .. || insn_n) has the
* F_OR bit set in all but the last instruction.
* The first match will set "skip_or", and cause
* the following instructions to be skipped until
* past the one with the F_OR bit clear.
*/
if (skip_or) { /* skip this instruction */
if ((cmd->len & F_OR) == 0)
skip_or = 0; /* next one is good */
continue;
}
match = 0; /* set to 1 if we succeed */
switch (cmd->opcode) {
/*
* The first set of opcodes compares the packet's
* fields with some pattern, setting 'match' if a
* match is found. At the end of the loop there is
* logic to deal with F_NOT and F_OR flags associated
* with the opcode.
*/
case O_NOP:
match = 1;
break;
case O_FORWARD_MAC:
printf("ipfw: opcode %d unimplemented\n",
cmd->opcode);
break;
case O_GID:
case O_UID:
case O_JAIL:
/*
* We only check offset == 0 && proto != 0,
* as this ensures that we have a
* packet with the ports info.
*/
if (offset != 0)
break;
if (proto == IPPROTO_TCP ||
proto == IPPROTO_UDP)
match = check_uidgid(
(ipfw_insn_u32 *)cmd,
args, &ucred_lookup,
#ifdef __FreeBSD__
&ucred_cache);
#else
(void *)&ucred_cache);
#endif
break;
case O_RECV:
match = iface_match(m->m_pkthdr.rcvif,
(ipfw_insn_if *)cmd, chain, &tablearg);
break;
case O_XMIT:
match = iface_match(oif, (ipfw_insn_if *)cmd,
chain, &tablearg);
break;
case O_VIA:
match = iface_match(oif ? oif :
m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd,
chain, &tablearg);
break;
case O_MACADDR2:
if (args->eh != NULL) { /* have MAC header */
u_int32_t *want = (u_int32_t *)
((ipfw_insn_mac *)cmd)->addr;
u_int32_t *mask = (u_int32_t *)
((ipfw_insn_mac *)cmd)->mask;
u_int32_t *hdr = (u_int32_t *)args->eh;
match =
( want[0] == (hdr[0] & mask[0]) &&
want[1] == (hdr[1] & mask[1]) &&
want[2] == (hdr[2] & mask[2]) );
}
break;
case O_MAC_TYPE:
if (args->eh != NULL) {
u_int16_t *p =
((ipfw_insn_u16 *)cmd)->ports;
int i;
for (i = cmdlen - 1; !match && i>0;
i--, p += 2)
match = (etype >= p[0] &&
etype <= p[1]);
}
break;
case O_FRAG:
match = (offset != 0);
break;
case O_IN: /* "out" is "not in" */
match = (oif == NULL);
break;
case O_LAYER2:
match = (args->eh != NULL);
break;
case O_DIVERTED:
{
/* For diverted packets, args->rule.info
* contains the divert port (in host format)
* reason and direction.
*/
uint32_t i = args->rule.info;
match = (i&IPFW_IS_MASK) == IPFW_IS_DIVERT &&
cmd->arg1 & ((i & IPFW_INFO_IN) ? 1 : 2);
}
break;
case O_PROTO:
/*
* We do not allow an arg of 0 so the
* check of "proto" only suffices.
*/
match = (proto == cmd->arg1);
break;
case O_IP_SRC:
match = is_ipv4 &&
(((ipfw_insn_ip *)cmd)->addr.s_addr ==
src_ip.s_addr);
break;
case O_IP_SRC_LOOKUP:
case O_IP_DST_LOOKUP:
if (is_ipv4) {
uint32_t key =
(cmd->opcode == O_IP_DST_LOOKUP) ?
dst_ip.s_addr : src_ip.s_addr;
uint32_t v = 0;
if (cmdlen > F_INSN_SIZE(ipfw_insn_u32)) {
/* generic lookup. The key must be
* in 32bit big-endian format.
*/
v = ((ipfw_insn_u32 *)cmd)->d[1];
if (v == 0)
key = dst_ip.s_addr;
else if (v == 1)
key = src_ip.s_addr;
else if (v == 6) /* dscp */
key = (ip->ip_tos >> 2) & 0x3f;
else if (offset != 0)
break;
else if (proto != IPPROTO_TCP &&
proto != IPPROTO_UDP)
break;
else if (v == 2)
key = dst_port;
else if (v == 3)
key = src_port;
#ifndef USERSPACE
else if (v == 4 || v == 5) {
check_uidgid(
(ipfw_insn_u32 *)cmd,
args, &ucred_lookup,
#ifdef __FreeBSD__
&ucred_cache);
if (v == 4 /* O_UID */)
key = ucred_cache->cr_uid;
else if (v == 5 /* O_JAIL */)
key = ucred_cache->cr_prison->pr_id;
#else /* !__FreeBSD__ */
(void *)&ucred_cache);
if (v ==4 /* O_UID */)
key = ucred_cache.uid;
else if (v == 5 /* O_JAIL */)
key = ucred_cache.xid;
#endif /* !__FreeBSD__ */
}
#endif /* !USERSPACE */
else
break;
}
match = ipfw_lookup_table(chain,
cmd->arg1, key, &v);
if (!match)
break;
if (cmdlen == F_INSN_SIZE(ipfw_insn_u32))
match =
((ipfw_insn_u32 *)cmd)->d[0] == v;
else
tablearg = v;
} else if (is_ipv6) {
uint32_t v = 0;
void *pkey = (cmd->opcode == O_IP_DST_LOOKUP) ?
&args->f_id.dst_ip6: &args->f_id.src_ip6;
match = ipfw_lookup_table_extended(chain,
cmd->arg1,
sizeof(struct in6_addr),
pkey, &v);
if (cmdlen == F_INSN_SIZE(ipfw_insn_u32))
match = ((ipfw_insn_u32 *)cmd)->d[0] == v;
if (match)
tablearg = v;
}
break;
case O_IP_FLOW_LOOKUP:
{
uint32_t v = 0;
match = ipfw_lookup_table_extended(chain,
cmd->arg1, 0, &args->f_id, &v);
if (cmdlen == F_INSN_SIZE(ipfw_insn_u32))
match = ((ipfw_insn_u32 *)cmd)->d[0] == v;
if (match)
tablearg = v;
}
break;
case O_IP_SRC_MASK:
case O_IP_DST_MASK:
if (is_ipv4) {
uint32_t a =
(cmd->opcode == O_IP_DST_MASK) ?
dst_ip.s_addr : src_ip.s_addr;
uint32_t *p = ((ipfw_insn_u32 *)cmd)->d;
int i = cmdlen-1;
for (; !match && i>0; i-= 2, p+= 2)
match = (p[0] == (a & p[1]));
}
break;
case O_IP_SRC_ME:
if (is_ipv4) {
struct ifnet *tif;
INADDR_TO_IFP(src_ip, tif);
match = (tif != NULL);
break;
}
#ifdef INET6
/* FALLTHROUGH */
case O_IP6_SRC_ME:
match= is_ipv6 && ipfw_localip6(&args->f_id.src_ip6);
#endif
break;
case O_IP_DST_SET:
case O_IP_SRC_SET:
if (is_ipv4) {
u_int32_t *d = (u_int32_t *)(cmd+1);
u_int32_t addr =
cmd->opcode == O_IP_DST_SET ?
args->f_id.dst_ip :
args->f_id.src_ip;
if (addr < d[0])
break;
addr -= d[0]; /* subtract base */
match = (addr < cmd->arg1) &&
( d[ 1 + (addr>>5)] &
(1<<(addr & 0x1f)) );
}
break;
case O_IP_DST:
match = is_ipv4 &&
(((ipfw_insn_ip *)cmd)->addr.s_addr ==
dst_ip.s_addr);
break;
case O_IP_DST_ME:
if (is_ipv4) {
struct ifnet *tif;
INADDR_TO_IFP(dst_ip, tif);
match = (tif != NULL);
break;
}
#ifdef INET6
/* FALLTHROUGH */
case O_IP6_DST_ME:
match= is_ipv6 && ipfw_localip6(&args->f_id.dst_ip6);
#endif
break;
case O_IP_SRCPORT:
case O_IP_DSTPORT:
/*
* offset == 0 && proto != 0 is enough
* to guarantee that we have a
* packet with port info.
*/
if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP)
&& offset == 0) {
u_int16_t x =
(cmd->opcode == O_IP_SRCPORT) ?
src_port : dst_port ;
u_int16_t *p =
((ipfw_insn_u16 *)cmd)->ports;
int i;
for (i = cmdlen - 1; !match && i>0;
i--, p += 2)
match = (x>=p[0] && x<=p[1]);
}
break;
case O_ICMPTYPE:
match = (offset == 0 && proto==IPPROTO_ICMP &&
icmptype_match(ICMP(ulp), (ipfw_insn_u32 *)cmd) );
break;
#ifdef INET6
case O_ICMP6TYPE:
match = is_ipv6 && offset == 0 &&
proto==IPPROTO_ICMPV6 &&
icmp6type_match(
ICMP6(ulp)->icmp6_type,
(ipfw_insn_u32 *)cmd);
break;
#endif /* INET6 */
case O_IPOPT:
match = (is_ipv4 &&
ipopts_match(ip, cmd) );
break;
case O_IPVER:
match = (is_ipv4 &&
cmd->arg1 == ip->ip_v);
break;
case O_IPID:
case O_IPLEN:
case O_IPTTL:
if (is_ipv4) { /* only for IP packets */
uint16_t x;
uint16_t *p;
int i;
if (cmd->opcode == O_IPLEN)
x = iplen;
else if (cmd->opcode == O_IPTTL)
x = ip->ip_ttl;
else /* must be IPID */
x = ntohs(ip->ip_id);
if (cmdlen == 1) {
match = (cmd->arg1 == x);
break;
}
/* otherwise we have ranges */
p = ((ipfw_insn_u16 *)cmd)->ports;
i = cmdlen - 1;
for (; !match && i>0; i--, p += 2)
match = (x >= p[0] && x <= p[1]);
}
break;
case O_IPPRECEDENCE:
match = (is_ipv4 &&
(cmd->arg1 == (ip->ip_tos & 0xe0)) );
break;
case O_IPTOS:
match = (is_ipv4 &&
flags_match(cmd, ip->ip_tos));
break;
case O_DSCP:
{
uint32_t *p;
uint16_t x;
p = ((ipfw_insn_u32 *)cmd)->d;
if (is_ipv4)
x = ip->ip_tos >> 2;
else if (is_ipv6) {
uint8_t *v;
v = &((struct ip6_hdr *)ip)->ip6_vfc;
x = (*v & 0x0F) << 2;
v++;
x |= *v >> 6;
} else
break;
/* DSCP bitmask is stored as low_u32 high_u32 */
if (x >= 32)
match = *(p + 1) & (1 << (x - 32));
else
match = *p & (1 << x);
}
break;
case O_TCPDATALEN:
if (proto == IPPROTO_TCP && offset == 0) {
struct tcphdr *tcp;
uint16_t x;
uint16_t *p;
int i;
tcp = TCP(ulp);
x = iplen -
((ip->ip_hl + tcp->th_off) << 2);
if (cmdlen == 1) {
match = (cmd->arg1 == x);
break;
}
/* otherwise we have ranges */
p = ((ipfw_insn_u16 *)cmd)->ports;
i = cmdlen - 1;
for (; !match && i>0; i--, p += 2)
match = (x >= p[0] && x <= p[1]);
}
break;
case O_TCPFLAGS:
match = (proto == IPPROTO_TCP && offset == 0 &&
flags_match(cmd, TCP(ulp)->th_flags));
break;
case O_TCPOPTS:
if (proto == IPPROTO_TCP && offset == 0 && ulp){
PULLUP_LEN(hlen, ulp,
(TCP(ulp)->th_off << 2));
match = tcpopts_match(TCP(ulp), cmd);
}
break;
case O_TCPSEQ:
match = (proto == IPPROTO_TCP && offset == 0 &&
((ipfw_insn_u32 *)cmd)->d[0] ==
TCP(ulp)->th_seq);
break;
case O_TCPACK:
match = (proto == IPPROTO_TCP && offset == 0 &&
((ipfw_insn_u32 *)cmd)->d[0] ==
TCP(ulp)->th_ack);
break;
case O_TCPWIN:
if (proto == IPPROTO_TCP && offset == 0) {
uint16_t x;
uint16_t *p;
int i;
x = ntohs(TCP(ulp)->th_win);
if (cmdlen == 1) {
match = (cmd->arg1 == x);
break;
}
/* Otherwise we have ranges. */
p = ((ipfw_insn_u16 *)cmd)->ports;
i = cmdlen - 1;
for (; !match && i > 0; i--, p += 2)
match = (x >= p[0] && x <= p[1]);
}
break;
case O_ESTAB:
/* reject packets which have SYN only */
/* XXX should i also check for TH_ACK ? */
match = (proto == IPPROTO_TCP && offset == 0 &&
(TCP(ulp)->th_flags &
(TH_RST | TH_ACK | TH_SYN)) != TH_SYN);
break;
case O_ALTQ: {
struct pf_mtag *at;
struct m_tag *mtag;
ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd;
/*
* ALTQ uses mbuf tags from another
* packet filtering system - pf(4).
* We allocate a tag in its format
* and fill it in, pretending to be pf(4).
*/
match = 1;
at = pf_find_mtag(m);
if (at != NULL && at->qid != 0)
break;
mtag = m_tag_get(PACKET_TAG_PF,
sizeof(struct pf_mtag), M_NOWAIT | M_ZERO);
if (mtag == NULL) {
/*
* Let the packet fall back to the
* default ALTQ.
*/
break;
}
m_tag_prepend(m, mtag);
at = (struct pf_mtag *)(mtag + 1);
at->qid = altq->qid;
at->hdr = ip;
break;
}
case O_LOG:
ipfw_log(chain, f, hlen, args, m,
oif, offset | ip6f_mf, tablearg, ip);
match = 1;
break;
case O_PROB:
match = (random()<((ipfw_insn_u32 *)cmd)->d[0]);
break;
case O_VERREVPATH:
/* Outgoing packets automatically pass/match */
match = ((oif != NULL) ||
(m->m_pkthdr.rcvif == NULL) ||
(
#ifdef INET6
is_ipv6 ?
verify_path6(&(args->f_id.src_ip6),
m->m_pkthdr.rcvif, args->f_id.fib) :
#endif
verify_path(src_ip, m->m_pkthdr.rcvif,
args->f_id.fib)));
break;
case O_VERSRCREACH:
/* Outgoing packets automatically pass/match */
match = (hlen > 0 && ((oif != NULL) ||
#ifdef INET6
is_ipv6 ?
verify_path6(&(args->f_id.src_ip6),
NULL, args->f_id.fib) :
#endif
verify_path(src_ip, NULL, args->f_id.fib)));
break;
case O_ANTISPOOF:
/* Outgoing packets automatically pass/match */
if (oif == NULL && hlen > 0 &&
( (is_ipv4 && in_localaddr(src_ip))
#ifdef INET6
|| (is_ipv6 &&
in6_localaddr(&(args->f_id.src_ip6)))
#endif
))
match =
#ifdef INET6
is_ipv6 ? verify_path6(
&(args->f_id.src_ip6),
m->m_pkthdr.rcvif,
args->f_id.fib) :
#endif
verify_path(src_ip,
m->m_pkthdr.rcvif,
args->f_id.fib);
else
match = 1;
break;
case O_IPSEC:
#ifdef IPSEC
match = (m_tag_find(m,
PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL);
#endif
/* otherwise no match */
break;
#ifdef INET6
case O_IP6_SRC:
match = is_ipv6 &&
IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6,
&((ipfw_insn_ip6 *)cmd)->addr6);
break;
case O_IP6_DST:
match = is_ipv6 &&
IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6,
&((ipfw_insn_ip6 *)cmd)->addr6);
break;
case O_IP6_SRC_MASK:
case O_IP6_DST_MASK:
if (is_ipv6) {
int i = cmdlen - 1;
struct in6_addr p;
struct in6_addr *d =
&((ipfw_insn_ip6 *)cmd)->addr6;
for (; !match && i > 0; d += 2,
i -= F_INSN_SIZE(struct in6_addr)
* 2) {
p = (cmd->opcode ==
O_IP6_SRC_MASK) ?
args->f_id.src_ip6:
args->f_id.dst_ip6;
APPLY_MASK(&p, &d[1]);
match =
IN6_ARE_ADDR_EQUAL(&d[0],
&p);
}
}
break;
case O_FLOW6ID:
match = is_ipv6 &&
flow6id_match(args->f_id.flow_id6,
(ipfw_insn_u32 *) cmd);
break;
case O_EXT_HDR:
match = is_ipv6 &&
(ext_hd & ((ipfw_insn *) cmd)->arg1);
break;
case O_IP6:
match = is_ipv6;
break;
#endif
case O_IP4:
match = is_ipv4;
break;
case O_TAG: {
struct m_tag *mtag;
uint32_t tag = TARG(cmd->arg1, tag);
/* Packet is already tagged with this tag? */
mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL);
/* We have `untag' action when F_NOT flag is
* present. And we must remove this mtag from
* mbuf and reset `match' to zero (`match' will
* be inversed later).
* Otherwise we should allocate new mtag and
* push it into mbuf.
*/
if (cmd->len & F_NOT) { /* `untag' action */
if (mtag != NULL)
m_tag_delete(m, mtag);
match = 0;
} else {
if (mtag == NULL) {
mtag = m_tag_alloc( MTAG_IPFW,
tag, 0, M_NOWAIT);
if (mtag != NULL)
m_tag_prepend(m, mtag);
}
match = 1;
}
break;
}
case O_FIB: /* try match the specified fib */
if (args->f_id.fib == cmd->arg1)
match = 1;
break;
case O_SOCKARG: {
#ifndef USERSPACE /* not supported in userspace */
struct inpcb *inp = args->inp;
struct inpcbinfo *pi;
if (is_ipv6) /* XXX can we remove this ? */
break;
if (proto == IPPROTO_TCP)
pi = &V_tcbinfo;
else if (proto == IPPROTO_UDP)
pi = &V_udbinfo;
else
break;
/*
* XXXRW: so_user_cookie should almost
* certainly be inp_user_cookie?
*/
/* For incoming packet, lookup up the
inpcb using the src/dest ip/port tuple */
if (inp == NULL) {
inp = in_pcblookup(pi,
src_ip, htons(src_port),
dst_ip, htons(dst_port),
INPLOOKUP_RLOCKPCB, NULL);
if (inp != NULL) {
tablearg =
inp->inp_socket->so_user_cookie;
if (tablearg)
match = 1;
INP_RUNLOCK(inp);
}
} else {
if (inp->inp_socket) {
tablearg =
inp->inp_socket->so_user_cookie;
if (tablearg)
match = 1;
}
}
#endif /* !USERSPACE */
break;
}
case O_TAGGED: {
struct m_tag *mtag;
uint32_t tag = TARG(cmd->arg1, tag);
if (cmdlen == 1) {
match = m_tag_locate(m, MTAG_IPFW,
tag, NULL) != NULL;
break;
}
/* we have ranges */
for (mtag = m_tag_first(m);
mtag != NULL && !match;
mtag = m_tag_next(m, mtag)) {
uint16_t *p;
int i;
if (mtag->m_tag_cookie != MTAG_IPFW)
continue;
p = ((ipfw_insn_u16 *)cmd)->ports;
i = cmdlen - 1;
for(; !match && i > 0; i--, p += 2)
match =
mtag->m_tag_id >= p[0] &&
mtag->m_tag_id <= p[1];
}
break;
}
/*
* The second set of opcodes represents 'actions',
* i.e. the terminal part of a rule once the packet
* matches all previous patterns.
* Typically there is only one action for each rule,
* and the opcode is stored at the end of the rule
* (but there are exceptions -- see below).
*
* In general, here we set retval and terminate the
* outer loop (would be a 'break 3' in some language,
* but we need to set l=0, done=1)
*
* Exceptions:
* O_COUNT and O_SKIPTO actions:
* instead of terminating, we jump to the next rule
* (setting l=0), or to the SKIPTO target (setting
* f/f_len, cmd and l as needed), respectively.
*
* O_TAG, O_LOG and O_ALTQ action parameters:
* perform some action and set match = 1;
*
* O_LIMIT and O_KEEP_STATE: these opcodes are
* not real 'actions', and are stored right
* before the 'action' part of the rule.
* These opcodes try to install an entry in the
* state tables; if successful, we continue with
* the next opcode (match=1; break;), otherwise
* the packet must be dropped (set retval,
* break loops with l=0, done=1)
*
* O_PROBE_STATE and O_CHECK_STATE: these opcodes
* cause a lookup of the state table, and a jump
* to the 'action' part of the parent rule
* if an entry is found, or
* (CHECK_STATE only) a jump to the next rule if
* the entry is not found.
* The result of the lookup is cached so that
* further instances of these opcodes become NOPs.
* The jump to the next rule is done by setting
* l=0, cmdlen=0.
*/
case O_LIMIT:
case O_KEEP_STATE:
if (ipfw_install_state(chain, f,
(ipfw_insn_limit *)cmd, args, tablearg)) {
/* error or limit violation */
retval = IP_FW_DENY;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
}
match = 1;
break;
case O_PROBE_STATE:
case O_CHECK_STATE:
/*
* dynamic rules are checked at the first
* keep-state or check-state occurrence,
* with the result being stored in dyn_dir.
* The compiler introduces a PROBE_STATE
* instruction for us when we have a
* KEEP_STATE (because PROBE_STATE needs
* to be run first).
*/
if (dyn_dir == MATCH_UNKNOWN &&
(q = ipfw_lookup_dyn_rule(&args->f_id,
&dyn_dir, proto == IPPROTO_TCP ?
TCP(ulp) : NULL))
!= NULL) {
/*
* Found dynamic entry, update stats
* and jump to the 'action' part of
* the parent rule by setting
* f, cmd, l and clearing cmdlen.
*/
IPFW_INC_DYN_COUNTER(q, pktlen);
/* XXX we would like to have f_pos
* readily accessible in the dynamic
* rule, instead of having to
* lookup q->rule.
*/
f = q->rule;
f_pos = ipfw_find_rule(chain,
f->rulenum, f->id);
cmd = ACTION_PTR(f);
l = f->cmd_len - f->act_ofs;
ipfw_dyn_unlock(q);
cmdlen = 0;
match = 1;
break;
}
/*
* Dynamic entry not found. If CHECK_STATE,
* skip to next rule, if PROBE_STATE just
* ignore and continue with next opcode.
*/
if (cmd->opcode == O_CHECK_STATE)
l = 0; /* exit inner loop */
match = 1;
break;
case O_ACCEPT:
retval = 0; /* accept */
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
case O_PIPE:
case O_QUEUE:
set_match(args, f_pos, chain);
args->rule.info = TARG(cmd->arg1, pipe);
if (cmd->opcode == O_PIPE)
args->rule.info |= IPFW_IS_PIPE;
if (V_fw_one_pass)
args->rule.info |= IPFW_ONEPASS;
retval = IP_FW_DUMMYNET;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
case O_DIVERT:
case O_TEE:
if (args->eh) /* not on layer 2 */
break;
/* otherwise this is terminal */
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
retval = (cmd->opcode == O_DIVERT) ?
IP_FW_DIVERT : IP_FW_TEE;
set_match(args, f_pos, chain);
args->rule.info = TARG(cmd->arg1, divert);
break;
case O_COUNT:
IPFW_INC_RULE_COUNTER(f, pktlen);
l = 0; /* exit inner loop */
break;
case O_SKIPTO:
IPFW_INC_RULE_COUNTER(f, pktlen);
f_pos = JUMP(chain, f, cmd->arg1, tablearg, 0);
/*
* Skip disabled rules, and re-enter
* the inner loop with the correct
* f_pos, f, l and cmd.
* Also clear cmdlen and skip_or
*/
for (; f_pos < chain->n_rules - 1 &&
(V_set_disable &
(1 << chain->map[f_pos]->set));
f_pos++)
;
/* Re-enter the inner loop at the skipto rule. */
f = chain->map[f_pos];
l = f->cmd_len;
cmd = f->cmd;
match = 1;
cmdlen = 0;
skip_or = 0;
continue;
break; /* not reached */
case O_CALLRETURN: {
/*
* Implementation of `subroutine' call/return,
* in the stack carried in an mbuf tag. This
* is different from `skipto' in that any call
* address is possible (`skipto' must prevent
* backward jumps to avoid endless loops).
* We have `return' action when F_NOT flag is
* present. The `m_tag_id' field is used as
* stack pointer.
*/
struct m_tag *mtag;
uint16_t jmpto, *stack;
#define IS_CALL ((cmd->len & F_NOT) == 0)
#define IS_RETURN ((cmd->len & F_NOT) != 0)
/*
* Hand-rolled version of m_tag_locate() with
* wildcard `type'.
* If not already tagged, allocate new tag.
*/
mtag = m_tag_first(m);
while (mtag != NULL) {
if (mtag->m_tag_cookie ==
MTAG_IPFW_CALL)
break;
mtag = m_tag_next(m, mtag);
}
if (mtag == NULL && IS_CALL) {
mtag = m_tag_alloc(MTAG_IPFW_CALL, 0,
IPFW_CALLSTACK_SIZE *
sizeof(uint16_t), M_NOWAIT);
if (mtag != NULL)
m_tag_prepend(m, mtag);
}
/*
* On error both `call' and `return' just
* continue with next rule.
*/
if (IS_RETURN && (mtag == NULL ||
mtag->m_tag_id == 0)) {
l = 0; /* exit inner loop */
break;
}
if (IS_CALL && (mtag == NULL ||
mtag->m_tag_id >= IPFW_CALLSTACK_SIZE)) {
printf("ipfw: call stack error, "
"go to next rule\n");
l = 0; /* exit inner loop */
break;
}
IPFW_INC_RULE_COUNTER(f, pktlen);
stack = (uint16_t *)(mtag + 1);
/*
* The `call' action may use cached f_pos
* (in f->next_rule), whose version is written
* in f->next_rule.
* The `return' action, however, doesn't have
* fixed jump address in cmd->arg1 and can't use
* cache.
*/
if (IS_CALL) {
stack[mtag->m_tag_id] = f->rulenum;
mtag->m_tag_id++;
f_pos = JUMP(chain, f, cmd->arg1,
tablearg, 1);
} else { /* `return' action */
mtag->m_tag_id--;
jmpto = stack[mtag->m_tag_id] + 1;
f_pos = ipfw_find_rule(chain, jmpto, 0);
}
/*
* Skip disabled rules, and re-enter
* the inner loop with the correct
* f_pos, f, l and cmd.
* Also clear cmdlen and skip_or
*/
for (; f_pos < chain->n_rules - 1 &&
(V_set_disable &
(1 << chain->map[f_pos]->set)); f_pos++)
;
/* Re-enter the inner loop at the dest rule. */
f = chain->map[f_pos];
l = f->cmd_len;
cmd = f->cmd;
cmdlen = 0;
skip_or = 0;
continue;
break; /* NOTREACHED */
}
#undef IS_CALL
#undef IS_RETURN
case O_REJECT:
/*
* Drop the packet and send a reject notice
* if the packet is not ICMP (or is an ICMP
* query), and it is not multicast/broadcast.
*/
if (hlen > 0 && is_ipv4 && offset == 0 &&
(proto != IPPROTO_ICMP ||
is_icmp_query(ICMP(ulp))) &&
!(m->m_flags & (M_BCAST|M_MCAST)) &&
!IN_MULTICAST(ntohl(dst_ip.s_addr))) {
send_reject(args, cmd->arg1, iplen, ip);
m = args->m;
}
/* FALLTHROUGH */
#ifdef INET6
case O_UNREACH6:
if (hlen > 0 && is_ipv6 &&
((offset & IP6F_OFF_MASK) == 0) &&
(proto != IPPROTO_ICMPV6 ||
(is_icmp6_query(icmp6_type) == 1)) &&
!(m->m_flags & (M_BCAST|M_MCAST)) &&
!IN6_IS_ADDR_MULTICAST(&args->f_id.dst_ip6)) {
send_reject6(
args, cmd->arg1, hlen,
(struct ip6_hdr *)ip);
m = args->m;
}
/* FALLTHROUGH */
#endif
case O_DENY:
retval = IP_FW_DENY;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
case O_FORWARD_IP:
if (args->eh) /* not valid on layer2 pkts */
break;
if (q == NULL || q->rule != f ||
dyn_dir == MATCH_FORWARD) {
struct sockaddr_in *sa;
sa = &(((ipfw_insn_sa *)cmd)->sa);
if (sa->sin_addr.s_addr == INADDR_ANY) {
#ifdef INET6
/*
* We use O_FORWARD_IP opcode for
* fwd rule with tablearg, but tables
* now support IPv6 addresses. And
* when we are inspecting IPv6 packet,
* we can use nh6 field from
* table_value as next_hop6 address.
*/
if (is_ipv6) {
struct sockaddr_in6 *sa6;
sa6 = args->next_hop6 =
&args->hopstore6;
sa6->sin6_family = AF_INET6;
sa6->sin6_len = sizeof(*sa6);
sa6->sin6_addr = TARG_VAL(
chain, tablearg, nh6);
/*
* Set sin6_scope_id only for
* link-local unicast addresses.
*/
if (IN6_IS_ADDR_LINKLOCAL(
&sa6->sin6_addr))
sa6->sin6_scope_id =
TARG_VAL(chain,
tablearg,
zoneid);
} else
#endif
{
sa = args->next_hop =
&args->hopstore;
sa->sin_family = AF_INET;
sa->sin_len = sizeof(*sa);
sa->sin_addr.s_addr = htonl(
TARG_VAL(chain, tablearg,
nh4));
}
} else {
args->next_hop = sa;
}
}
retval = IP_FW_PASS;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
#ifdef INET6
case O_FORWARD_IP6:
if (args->eh) /* not valid on layer2 pkts */
break;
if (q == NULL || q->rule != f ||
dyn_dir == MATCH_FORWARD) {
struct sockaddr_in6 *sin6;
sin6 = &(((ipfw_insn_sa6 *)cmd)->sa);
args->next_hop6 = sin6;
}
retval = IP_FW_PASS;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
#endif
case O_NETGRAPH:
case O_NGTEE:
set_match(args, f_pos, chain);
args->rule.info = TARG(cmd->arg1, netgraph);
if (V_fw_one_pass)
args->rule.info |= IPFW_ONEPASS;
retval = (cmd->opcode == O_NETGRAPH) ?
IP_FW_NETGRAPH : IP_FW_NGTEE;
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
break;
case O_SETFIB: {
uint32_t fib;
IPFW_INC_RULE_COUNTER(f, pktlen);
fib = TARG(cmd->arg1, fib) & 0x7FFF;
if (fib >= rt_numfibs)
fib = 0;
M_SETFIB(m, fib);
args->f_id.fib = fib;
l = 0; /* exit inner loop */
break;
}
case O_SETDSCP: {
uint16_t code;
code = TARG(cmd->arg1, dscp) & 0x3F;
l = 0; /* exit inner loop */
if (is_ipv4) {
uint16_t old;
old = *(uint16_t *)ip;
ip->ip_tos = (code << 2) |
(ip->ip_tos & 0x03);
ip->ip_sum = cksum_adjust(ip->ip_sum,
old, *(uint16_t *)ip);
} else if (is_ipv6) {
uint8_t *v;
v = &((struct ip6_hdr *)ip)->ip6_vfc;
*v = (*v & 0xF0) | (code >> 2);
v++;
*v = (*v & 0x3F) | ((code & 0x03) << 6);
} else
break;
IPFW_INC_RULE_COUNTER(f, pktlen);
break;
}
case O_NAT:
l = 0; /* exit inner loop */
done = 1; /* exit outer loop */
if (!IPFW_NAT_LOADED) {
retval = IP_FW_DENY;
break;
}
struct cfg_nat *t;
int nat_id;
set_match(args, f_pos, chain);
/* Check if this is 'global' nat rule */
if (cmd->arg1 == 0) {
retval = ipfw_nat_ptr(args, NULL, m);
break;
}
t = ((ipfw_insn_nat *)cmd)->nat;
if (t == NULL) {
nat_id = TARG(cmd->arg1, nat);
t = (*lookup_nat_ptr)(&chain->nat, nat_id);
if (t == NULL) {
retval = IP_FW_DENY;
break;
}
if (cmd->arg1 != IP_FW_TARG)
((ipfw_insn_nat *)cmd)->nat = t;
}
retval = ipfw_nat_ptr(args, t, m);
break;
case O_REASS: {
int ip_off;
IPFW_INC_RULE_COUNTER(f, pktlen);
l = 0; /* in any case exit inner loop */
ip_off = ntohs(ip->ip_off);
/* if not fragmented, go to next rule */
if ((ip_off & (IP_MF | IP_OFFMASK)) == 0)
break;
args->m = m = ip_reass(m);
/*
* do IP header checksum fixup.
*/
if (m == NULL) { /* fragment got swallowed */
retval = IP_FW_DENY;
} else { /* good, packet complete */
int hlen;
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
ip->ip_sum = 0;
if (hlen == sizeof(struct ip))
ip->ip_sum = in_cksum_hdr(ip);
else
ip->ip_sum = in_cksum(m, hlen);
retval = IP_FW_REASS;
set_match(args, f_pos, chain);
}
done = 1; /* exit outer loop */
break;
}
case O_EXTERNAL_ACTION:
l = 0; /* in any case exit inner loop */
retval = ipfw_run_eaction(chain, args,
cmd, &done);
break;
default:
panic("-- unknown opcode %d\n", cmd->opcode);
} /* end of switch() on opcodes */
/*
* if we get here with l=0, then match is irrelevant.
*/
if (cmd->len & F_NOT)
match = !match;
if (match) {
if (cmd->len & F_OR)
skip_or = 1;
} else {
if (!(cmd->len & F_OR)) /* not an OR block, */
break; /* try next rule */
}
} /* end of inner loop, scan opcodes */
#undef PULLUP_LEN
if (done)
break;
/* next_rule:; */ /* try next rule */
} /* end of outer for, scan rules */
if (done) {
struct ip_fw *rule = chain->map[f_pos];
/* Update statistics */
IPFW_INC_RULE_COUNTER(rule, pktlen);
} else {
retval = IP_FW_DENY;
printf("ipfw: ouch!, skip past end of rules, denying packet\n");
}
IPFW_PF_RUNLOCK(chain);
#ifdef __FreeBSD__
if (ucred_cache != NULL)
crfree(ucred_cache);
#endif
return (retval);
pullup_failed:
if (V_fw_verbose)
printf("ipfw: pullup failed\n");
return (IP_FW_DENY);
}
/*
* Set maximum number of tables that can be used in given VNET ipfw instance.
*/
#ifdef SYSCTL_NODE
static int
sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS)
{
int error;
unsigned int ntables;
ntables = V_fw_tables_max;
error = sysctl_handle_int(oidp, &ntables, 0, req);
/* Read operation or some error */
if ((error != 0) || (req->newptr == NULL))
return (error);
return (ipfw_resize_tables(&V_layer3_chain, ntables));
}
/*
* Switches table namespace between global and per-set.
*/
static int
sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS)
{
int error;
unsigned int sets;
sets = V_fw_tables_sets;
error = sysctl_handle_int(oidp, &sets, 0, req);
/* Read operation or some error */
if ((error != 0) || (req->newptr == NULL))
return (error);
return (ipfw_switch_tables_namespace(&V_layer3_chain, sets));
}
#endif
/*
* Module and VNET glue
*/
/*
* Stuff that must be initialised only on boot or module load
*/
static int
ipfw_init(void)
{
int error = 0;
/*
* Only print out this stuff the first time around,
* when called from the sysinit code.
*/
printf("ipfw2 "
#ifdef INET6
"(+ipv6) "
#endif
"initialized, divert %s, nat %s, "
"default to %s, logging ",
#ifdef IPDIVERT
"enabled",
#else
"loadable",
#endif
#ifdef IPFIREWALL_NAT
"enabled",
#else
"loadable",
#endif
default_to_accept ? "accept" : "deny");
/*
* Note: V_xxx variables can be accessed here but the vnet specific
* initializer may not have been called yet for the VIMAGE case.
* Tuneables will have been processed. We will print out values for
* the default vnet.
* XXX This should all be rationalized AFTER 8.0
*/
if (V_fw_verbose == 0)
printf("disabled\n");
else if (V_verbose_limit == 0)
printf("unlimited\n");
else
printf("limited to %d packets/entry by default\n",
V_verbose_limit);
/* Check user-supplied table count for validness */
if (default_fw_tables > IPFW_TABLES_MAX)
default_fw_tables = IPFW_TABLES_MAX;
ipfw_init_sopt_handler();
ipfw_log_bpf(1); /* init */
ipfw_iface_init();
return (error);
}
/*
* Called for the removal of the last instance only on module unload.
*/
static void
ipfw_destroy(void)
{
ipfw_iface_destroy();
ipfw_log_bpf(0); /* uninit */
ipfw_destroy_sopt_handler();
printf("IP firewall unloaded\n");
}
/*
* Stuff that must be initialized for every instance
* (including the first of course).
*/
static int
vnet_ipfw_init(const void *unused)
{
int error, first;
struct ip_fw *rule = NULL;
struct ip_fw_chain *chain;
chain = &V_layer3_chain;
first = IS_DEFAULT_VNET(curvnet) ? 1 : 0;
/* First set up some values that are compile time options */
V_autoinc_step = 100; /* bounded to 1..1000 in add_rule() */
V_fw_deny_unknown_exthdrs = 1;
#ifdef IPFIREWALL_VERBOSE
V_fw_verbose = 1;
#endif
#ifdef IPFIREWALL_VERBOSE_LIMIT
V_verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
#endif
#ifdef IPFIREWALL_NAT
LIST_INIT(&chain->nat);
#endif
/* Init shared services hash table */
ipfw_init_srv(chain);
ipfw_init_obj_rewriter();
ipfw_init_counters();
/* insert the default rule and create the initial map */
chain->n_rules = 1;
chain->map = malloc(sizeof(struct ip_fw *), M_IPFW, M_WAITOK | M_ZERO);
rule = ipfw_alloc_rule(chain, sizeof(struct ip_fw));
/* Set initial number of tables */
V_fw_tables_max = default_fw_tables;
error = ipfw_init_tables(chain, first);
if (error) {
printf("ipfw2: setting up tables failed\n");
free(chain->map, M_IPFW);
free(rule, M_IPFW);
return (ENOSPC);
}
/* fill and insert the default rule */
rule->act_ofs = 0;
rule->rulenum = IPFW_DEFAULT_RULE;
rule->cmd_len = 1;
rule->set = RESVD_SET;
rule->cmd[0].len = 1;
rule->cmd[0].opcode = default_to_accept ? O_ACCEPT : O_DENY;
chain->default_rule = chain->map[0] = rule;
chain->id = rule->id = 1;
/* Pre-calculate rules length for legacy dump format */
chain->static_len = sizeof(struct ip_fw_rule0);
IPFW_LOCK_INIT(chain);
ipfw_dyn_init(chain);
ipfw_eaction_init(chain, first);
#ifdef LINEAR_SKIPTO
ipfw_init_skipto_cache(chain);
#endif
/* First set up some values that are compile time options */
V_ipfw_vnet_ready = 1; /* Open for business */
/*
* Hook the sockopt handler and pfil hooks for ipv4 and ipv6.
* Even if the latter two fail we still keep the module alive
* because the sockopt and layer2 paths are still useful.
* ipfw[6]_hook return 0 on success, ENOENT on failure,
* so we can ignore the exact return value and just set a flag.
*
* Note that V_fw[6]_enable are manipulated by a SYSCTL_PROC so
* changes in the underlying (per-vnet) variables trigger
* immediate hook()/unhook() calls.
* In layer2 we have the same behaviour, except that V_ether_ipfw
* is checked on each packet because there are no pfil hooks.
*/
V_ip_fw_ctl_ptr = ipfw_ctl3;
error = ipfw_attach_hooks(1);
return (error);
}
/*
* Called for the removal of each instance.
*/
static int
vnet_ipfw_uninit(const void *unused)
{
struct ip_fw *reap;
struct ip_fw_chain *chain = &V_layer3_chain;
int i, last;
V_ipfw_vnet_ready = 0; /* tell new callers to go away */
/*
* disconnect from ipv4, ipv6, layer2 and sockopt.
* Then grab, release and grab again the WLOCK so we make
* sure the update is propagated and nobody will be in.
*/
(void)ipfw_attach_hooks(0 /* detach */);
V_ip_fw_ctl_ptr = NULL;
last = IS_DEFAULT_VNET(curvnet) ? 1 : 0;
IPFW_UH_WLOCK(chain);
IPFW_UH_WUNLOCK(chain);
ipfw_dyn_uninit(0); /* run the callout_drain */
IPFW_UH_WLOCK(chain);
reap = NULL;
IPFW_WLOCK(chain);
for (i = 0; i < chain->n_rules; i++)
ipfw_reap_add(chain, &reap, chain->map[i]);
free(chain->map, M_IPFW);
#ifdef LINEAR_SKIPTO
ipfw_destroy_skipto_cache(chain);
#endif
IPFW_WUNLOCK(chain);
IPFW_UH_WUNLOCK(chain);
ipfw_destroy_tables(chain, last);
ipfw_eaction_uninit(chain, last);
if (reap != NULL)
ipfw_reap_rules(reap);
vnet_ipfw_iface_destroy(chain);
ipfw_destroy_srv(chain);
IPFW_LOCK_DESTROY(chain);
ipfw_dyn_uninit(1); /* free the remaining parts */
ipfw_destroy_counters();
ipfw_destroy_obj_rewriter();
return (0);
}
/*
* Module event handler.
* In general we have the choice of handling most of these events by the
* event handler or by the (VNET_)SYS(UN)INIT handlers. I have chosen to
* use the SYSINIT handlers as they are more capable of expressing the
* flow of control during module and vnet operations, so this is just
* a skeleton. Note there is no SYSINIT equivalent of the module
* SHUTDOWN handler, but we don't have anything to do in that case anyhow.
*/
static int
ipfw_modevent(module_t mod, int type, void *unused)
{
int err = 0;
switch (type) {
case MOD_LOAD:
/* Called once at module load or
* system boot if compiled in. */
break;
case MOD_QUIESCE:
/* Called before unload. May veto unloading. */
break;
case MOD_UNLOAD:
/* Called during unload. */
break;
case MOD_SHUTDOWN:
/* Called during system shutdown. */
break;
default:
err = EOPNOTSUPP;
break;
}
return err;
}
static moduledata_t ipfwmod = {
"ipfw",
ipfw_modevent,
0
};
/* Define startup order. */
#define IPFW_SI_SUB_FIREWALL SI_SUB_PROTO_IFATTACHDOMAIN
#define IPFW_MODEVENT_ORDER (SI_ORDER_ANY - 255) /* On boot slot in here. */
#define IPFW_MODULE_ORDER (IPFW_MODEVENT_ORDER + 1) /* A little later. */
#define IPFW_VNET_ORDER (IPFW_MODEVENT_ORDER + 2) /* Later still. */
DECLARE_MODULE(ipfw, ipfwmod, IPFW_SI_SUB_FIREWALL, IPFW_MODEVENT_ORDER);
FEATURE(ipfw_ctl3, "ipfw new sockopt calls");
MODULE_VERSION(ipfw, 3);
/* should declare some dependencies here */
/*
* Starting up. Done in order after ipfwmod() has been called.
* VNET_SYSINIT is also called for each existing vnet and each new vnet.
*/
SYSINIT(ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER,
ipfw_init, NULL);
VNET_SYSINIT(vnet_ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER,
vnet_ipfw_init, NULL);
/*
* Closing up shop. These are done in REVERSE ORDER, but still
* after ipfwmod() has been called. Not called on reboot.
* VNET_SYSUNINIT is also called for each exiting vnet as it exits.
* or when the module is unloaded.
*/
SYSUNINIT(ipfw_destroy, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER,
ipfw_destroy, NULL);
VNET_SYSUNINIT(vnet_ipfw_uninit, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER,
vnet_ipfw_uninit, NULL);
/* end of file */
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