2b25acc158
packet forwarding state ("annotations") during ip processing.
The code is considerably cleaner now.
The variables removed by this change are:
ip_divert_cookie used by divert sockets
ip_fw_fwd_addr used for transparent ip redirection
last_pkt used by dynamic pipes in dummynet
Removal of the first two has been done by carrying the annotations
into volatile structs prepended to the mbuf chains, and adding
appropriate code to add/remove annotations in the routines which
make use of them, i.e. ip_input(), ip_output(), tcp_input(),
bdg_forward(), ether_demux(), ether_output_frame(), div_output().
On passing, remove a bug in divert handling of fragmented packet.
Now it is the fragment at offset 0 which sets the divert status of
the whole packet, whereas formerly it was the last incoming fragment
to decide.
Removal of last_pkt required a change in the interface of ip_fw_chk()
and dummynet_io(). On passing, use the same mechanism for dummynet
annotations and for divert/forward annotations.
option IPFIREWALL_FORWARD is effectively useless, the code to
implement it is very small and is now in by default to avoid the
obfuscation of conditionally compiled code.
NOTES:
* there is at least one global variable left, sro_fwd, in ip_output().
I am not sure if/how this can be removed.
* I have deliberately avoided gratuitous style changes in this commit
to avoid cluttering the diffs. Minor stule cleanup will likely be
necessary
* this commit only focused on the IP layer. I am sure there is a
number of global variables used in the TCP and maybe UDP stack.
* despite the number of files touched, there are absolutely no API's
or data structures changed by this commit (except the interfaces of
ip_fw_chk() and dummynet_io(), which are internal anyways), so
an MFC is quite safe and unintrusive (and desirable, given the
improved readability of the code).
MFC after: 10 days
360 lines
12 KiB
C
360 lines
12 KiB
C
/*
|
|
* Copyright (c) 1993 Daniel Boulet
|
|
* Copyright (c) 1994 Ugen J.S.Antsilevich
|
|
*
|
|
* Redistribution and use in source forms, with and without modification,
|
|
* are permitted provided that this entire comment appears intact.
|
|
*
|
|
* Redistribution in binary form may occur without any restrictions.
|
|
* Obviously, it would be nice if you gave credit where credit is due
|
|
* but requiring it would be too onerous.
|
|
*
|
|
* This software is provided ``AS IS'' without any warranties of any kind.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#ifndef _IP_FW_H
|
|
#define _IP_FW_H
|
|
|
|
#include <sys/queue.h>
|
|
|
|
/*
|
|
* This union structure identifies an interface, either explicitly
|
|
* by name or implicitly by IP address. The flags IP_FW_F_IIFNAME
|
|
* and IP_FW_F_OIFNAME say how to interpret this structure. An
|
|
* interface unit number of -1 matches any unit number, while an
|
|
* IP address of 0.0.0.0 indicates matches any interface.
|
|
*
|
|
* The receive and transmit interfaces are only compared against the
|
|
* the packet if the corresponding bit (IP_FW_F_IIFACE or IP_FW_F_OIFACE)
|
|
* is set. Note some packets lack a receive or transmit interface
|
|
* (in which case the missing "interface" never matches).
|
|
*/
|
|
|
|
union ip_fw_if {
|
|
struct in_addr fu_via_ip; /* Specified by IP address */
|
|
struct { /* Specified by interface name */
|
|
#define FW_IFNLEN 10 /* need room ! was IFNAMSIZ */
|
|
char name[FW_IFNLEN];
|
|
short unit; /* -1 means match any unit */
|
|
} fu_via_if;
|
|
};
|
|
|
|
/*
|
|
* Format of an IP firewall descriptor
|
|
*
|
|
* fw_src, fw_dst, fw_smsk, fw_dmsk are always stored in network byte order.
|
|
* fw_flg and fw_n*p are stored in host byte order (of course).
|
|
* Port numbers are stored in HOST byte order.
|
|
*/
|
|
|
|
/*
|
|
* To match MAC headers:
|
|
* 12 bytes at fw_mac_hdr contain the dst-src MAC address after masking.
|
|
* 12 bytes at fw_mac_mask contain the mask to apply to dst-src
|
|
* 2 bytes at fw_mac_type contain the mac type after mask (in net format)
|
|
* 2 bytes at fw_mac_type_mask contain the mac type mask
|
|
* If IP_FW_F_SRNG, the two contain the low-high of a range of types.
|
|
* IP_FW_F_DRNG is used to indicare we want to match a vlan.
|
|
*/
|
|
#define fw_mac_hdr fw_src
|
|
#define fw_mac_mask fw_uar
|
|
#define fw_mac_type fw_iplen
|
|
#define fw_mac_mask_type fw_ipid
|
|
|
|
struct ip_fw {
|
|
LIST_ENTRY(ip_fw) next; /* bidirectional list of rules */
|
|
u_int fw_flg; /* Operational Flags word */
|
|
u_int64_t fw_pcnt; /* Packet counters */
|
|
u_int64_t fw_bcnt; /* Byte counters */
|
|
|
|
struct in_addr fw_src; /* Source IP address */
|
|
struct in_addr fw_dst; /* Destination IP address */
|
|
struct in_addr fw_smsk; /* Mask for source IP address */
|
|
struct in_addr fw_dmsk; /* Mask for destination address */
|
|
u_short fw_number; /* Rule number */
|
|
u_char fw_prot; /* IP protocol */
|
|
#if 1
|
|
u_char fw_nports; /* # of src/dst port in array */
|
|
#define IP_FW_GETNSRCP(rule) ((rule)->fw_nports & 0x0f)
|
|
#define IP_FW_SETNSRCP(rule, n) do { \
|
|
(rule)->fw_nports &= ~0x0f; \
|
|
(rule)->fw_nports |= (n); \
|
|
} while (0)
|
|
#define IP_FW_GETNDSTP(rule) ((rule)->fw_nports >> 4)
|
|
#define IP_FW_SETNDSTP(rule, n) do { \
|
|
(rule)->fw_nports &= ~0xf0; \
|
|
(rule)->fw_nports |= (n) << 4;\
|
|
} while (0)
|
|
#define IP_FW_HAVEPORTS(rule) ((rule)->fw_nports != 0)
|
|
#else
|
|
u_char __pad[1];
|
|
u_int _nsrcp;
|
|
u_int _ndstp;
|
|
#define IP_FW_GETNSRCP(rule) (rule)->_nsrcp
|
|
#define IP_FW_SETNSRCP(rule,n) (rule)->_nsrcp = n
|
|
#define IP_FW_GETNDSTP(rule) (rule)->_ndstp
|
|
#define IP_FW_SETNDSTP(rule,n) (rule)->_ndstp = n
|
|
#define IP_FW_HAVEPORTS(rule) ((rule)->_ndstp + (rule)->_nsrcp != 0)
|
|
#endif
|
|
#define IP_FW_MAX_PORTS 10 /* A reasonable maximum */
|
|
union {
|
|
u_short fw_pts[IP_FW_MAX_PORTS]; /* port numbers to match */
|
|
#define IP_FW_ICMPTYPES_MAX 128
|
|
#define IP_FW_ICMPTYPES_DIM (IP_FW_ICMPTYPES_MAX / (sizeof(unsigned) * 8))
|
|
unsigned fw_icmptypes[IP_FW_ICMPTYPES_DIM]; /*ICMP types bitmap*/
|
|
} fw_uar;
|
|
|
|
u_int fw_ipflg; /* IP flags word */
|
|
u_short fw_iplen; /* IP length */
|
|
u_short fw_ipid; /* Identification */
|
|
u_char fw_ipopt; /* IP options set */
|
|
u_char fw_ipnopt; /* IP options unset */
|
|
u_char fw_iptos; /* IP type of service set */
|
|
u_char fw_ipntos; /* IP type of service unset */
|
|
u_char fw_ipttl; /* IP time to live */
|
|
u_int fw_ipver:4; /* IP version */
|
|
u_char fw_tcpopt; /* TCP options set */
|
|
u_char fw_tcpnopt; /* TCP options unset */
|
|
u_char fw_tcpf; /* TCP flags set */
|
|
u_char fw_tcpnf; /* TCP flags unset */
|
|
u_short fw_tcpwin; /* TCP window size */
|
|
u_int32_t fw_tcpseq; /* TCP sequence */
|
|
u_int32_t fw_tcpack; /* TCP acknowledgement */
|
|
long timestamp; /* timestamp (tv_sec) of last match */
|
|
union ip_fw_if fw_in_if; /* Incoming interfaces */
|
|
union ip_fw_if fw_out_if; /* Outgoing interfaces */
|
|
union {
|
|
u_short fu_divert_port; /* Divert/tee port (options IPDIVERT) */
|
|
u_short fu_pipe_nr; /* queue number (option DUMMYNET) */
|
|
u_short fu_skipto_rule; /* SKIPTO command rule number */
|
|
u_short fu_reject_code; /* REJECT response code */
|
|
struct sockaddr_in fu_fwd_ip;
|
|
} fw_un;
|
|
void *pipe_ptr; /* flow_set ptr for dummynet pipe */
|
|
void *next_rule_ptr; /* next rule in case of match */
|
|
uid_t fw_uid; /* uid to match */
|
|
gid_t fw_gid; /* gid to match */
|
|
int fw_logamount; /* amount to log */
|
|
u_int64_t fw_loghighest; /* highest number packet to log */
|
|
|
|
long dont_match_prob; /* 0x7fffffff means 1.0, always fail */
|
|
u_char dyn_type; /* type for dynamic rule */
|
|
|
|
#define DYN_KEEP_STATE 0 /* type for keep-state rules */
|
|
#define DYN_LIMIT 1 /* type for limit connection rules */
|
|
#define DYN_LIMIT_PARENT 2 /* parent entry for limit connection rules */
|
|
|
|
/* following two fields are used to limit number of connections
|
|
* basing on either src, srcport, dst, dstport.
|
|
*/
|
|
u_char limit_mask; /* mask type for limit rule, can
|
|
* have many.
|
|
*/
|
|
#define DYN_SRC_ADDR 0x1
|
|
#define DYN_SRC_PORT 0x2
|
|
#define DYN_DST_ADDR 0x4
|
|
#define DYN_DST_PORT 0x8
|
|
|
|
u_short conn_limit; /* # of connections for limit rule */
|
|
};
|
|
|
|
#define fw_divert_port fw_un.fu_divert_port
|
|
#define fw_skipto_rule fw_un.fu_skipto_rule
|
|
#define fw_reject_code fw_un.fu_reject_code
|
|
#define fw_pipe_nr fw_un.fu_pipe_nr
|
|
#define fw_fwd_ip fw_un.fu_fwd_ip
|
|
|
|
/*
|
|
*
|
|
* rule_ptr -------------+
|
|
* V
|
|
* [ next.le_next ]---->[ next.le_next ]---- [ next.le_next ]--->
|
|
* [ next.le_prev ]<----[ next.le_prev ]<----[ next.le_prev ]<---
|
|
* [ <ip_fw> body ] [ <ip_fw> body ] [ <ip_fw> body ]
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* Flow mask/flow id for each queue.
|
|
*/
|
|
struct ipfw_flow_id {
|
|
u_int32_t dst_ip;
|
|
u_int32_t src_ip;
|
|
u_int16_t dst_port;
|
|
u_int16_t src_port;
|
|
u_int8_t proto;
|
|
u_int8_t flags; /* protocol-specific flags */
|
|
};
|
|
|
|
/*
|
|
* dynamic ipfw rule
|
|
*/
|
|
struct ipfw_dyn_rule {
|
|
struct ipfw_dyn_rule *next;
|
|
struct ipfw_flow_id id; /* (masked) flow id */
|
|
struct ip_fw *rule; /* pointer to rule */
|
|
struct ipfw_dyn_rule *parent; /* pointer to parent rule */
|
|
u_int32_t expire; /* expire time */
|
|
u_int64_t pcnt; /* packet match counters */
|
|
u_int64_t bcnt; /* byte match counters */
|
|
u_int32_t bucket; /* which bucket in hash table */
|
|
u_int32_t state; /* state of this rule (typically a
|
|
* combination of TCP flags)
|
|
*/
|
|
u_int16_t dyn_type; /* rule type */
|
|
u_int16_t count; /* refcount */
|
|
};
|
|
|
|
/*
|
|
* Values for "flags" field .
|
|
*/
|
|
#define IP_FW_F_COMMAND 0x000000ff /* Mask for type of chain entry: */
|
|
#define IP_FW_F_DENY 0x00000000 /* This is a deny rule */
|
|
#define IP_FW_F_REJECT 0x00000001 /* Deny and send a response packet */
|
|
#define IP_FW_F_ACCEPT 0x00000002 /* This is an accept rule */
|
|
#define IP_FW_F_COUNT 0x00000003 /* This is a count rule */
|
|
#define IP_FW_F_DIVERT 0x00000004 /* This is a divert rule */
|
|
#define IP_FW_F_TEE 0x00000005 /* This is a tee rule */
|
|
#define IP_FW_F_SKIPTO 0x00000006 /* This is a skipto rule */
|
|
#define IP_FW_F_FWD 0x00000007 /* This is a "change forwarding
|
|
* address" rule
|
|
*/
|
|
#define IP_FW_F_PIPE 0x00000008 /* This is a dummynet rule */
|
|
#define IP_FW_F_QUEUE 0x00000009 /* This is a dummynet queue */
|
|
|
|
#define IP_FW_F_IN 0x00000100 /* Check inbound packets */
|
|
#define IP_FW_F_OUT 0x00000200 /* Check outbound packets */
|
|
#define IP_FW_F_IIFACE 0x00000400 /* Apply inbound interface test */
|
|
#define IP_FW_F_OIFACE 0x00000800 /* Apply outbound interface test */
|
|
#define IP_FW_F_PRN 0x00001000 /* Print if this rule matches */
|
|
#define IP_FW_F_SRNG 0x00002000 /* The first two src ports are a min
|
|
* and max range (stored in host byte
|
|
* order).
|
|
*/
|
|
#define IP_FW_F_DRNG 0x00004000 /* The first two dst ports are a min
|
|
* and max range (stored in host byte
|
|
* order).
|
|
*/
|
|
#define IP_FW_F_FRAG 0x00008000 /* Fragment */
|
|
#define IP_FW_F_IIFNAME 0x00010000 /* In interface by name/unit (not IP) */
|
|
#define IP_FW_F_OIFNAME 0x00020000 /* Out interface by name/unit (not IP)*/
|
|
#define IP_FW_F_INVSRC 0x00040000 /* Invert sense of src check */
|
|
#define IP_FW_F_INVDST 0x00080000 /* Invert sense of dst check */
|
|
#define IP_FW_F_ICMPBIT 0x00100000 /* ICMP type bitmap is valid */
|
|
#define IP_FW_F_UID 0x00200000 /* filter by uid */
|
|
#define IP_FW_F_GID 0x00400000 /* filter by gid */
|
|
#define IP_FW_F_RND_MATCH 0x00800000 /* probabilistic rule match */
|
|
#define IP_FW_F_SMSK 0x01000000 /* src-port + mask */
|
|
#define IP_FW_F_DMSK 0x02000000 /* dst-port + mask */
|
|
#define IP_FW_BRIDGED 0x04000000 /* only match bridged packets */
|
|
#define IP_FW_F_KEEP_S 0x08000000 /* keep state */
|
|
#define IP_FW_F_CHECK_S 0x10000000 /* check state */
|
|
#define IP_FW_F_SME 0x20000000 /* source = me */
|
|
#define IP_FW_F_DME 0x40000000 /* destination = me */
|
|
#define IP_FW_F_MAC 0x80000000 /* match MAC header */
|
|
|
|
#define IP_FW_F_MASK 0xFFFFFFFF /* All possible flag bits mask */
|
|
|
|
/*
|
|
* Flags for the 'fw_ipflg' field, for comparing values
|
|
* of ip and its protocols.
|
|
*/
|
|
#define IP_FW_IF_TCPOPT 0x00000001 /* tcp options */
|
|
#define IP_FW_IF_TCPFLG 0x00000002 /* tcp flags */
|
|
#define IP_FW_IF_TCPSEQ 0x00000004 /* tcp sequence number */
|
|
#define IP_FW_IF_TCPACK 0x00000008 /* tcp acknowledgement number */
|
|
#define IP_FW_IF_TCPWIN 0x00000010 /* tcp window size */
|
|
#define IP_FW_IF_TCPEST 0x00000020 /* established TCP connection */
|
|
#define IP_FW_IF_TCPMSK 0x0000003f /* mask of all tcp values */
|
|
#define IP_FW_IF_IPOPT 0x00000100 /* ip options */
|
|
#define IP_FW_IF_IPLEN 0x00000200 /* ip length */
|
|
#define IP_FW_IF_IPID 0x00000400 /* ip identification */
|
|
#define IP_FW_IF_IPTOS 0x00000800 /* ip type of service */
|
|
#define IP_FW_IF_IPTTL 0x00001000 /* ip time to live */
|
|
#define IP_FW_IF_IPVER 0x00002000 /* ip version */
|
|
#define IP_FW_IF_IPPRE 0x00004000 /* ip precedence */
|
|
#define IP_FW_IF_IPMSK 0x00007f00 /* mask of all ip values */
|
|
#define IP_FW_IF_MSK 0x0000ffff /* All possible bits mask */
|
|
|
|
/*
|
|
* For backwards compatibility with rules specifying "via iface" but
|
|
* not restricted to only "in" or "out" packets, we define this combination
|
|
* of bits to represent this configuration.
|
|
*/
|
|
|
|
#define IF_FW_F_VIAHACK (IP_FW_F_IN|IP_FW_F_OUT|IP_FW_F_IIFACE|IP_FW_F_OIFACE)
|
|
|
|
/*
|
|
* Definitions for REJECT response codes.
|
|
* Values less than 256 correspond to ICMP unreachable codes.
|
|
*/
|
|
#define IP_FW_REJECT_RST 0x0100 /* TCP packets: send RST */
|
|
|
|
/*
|
|
* Definitions for IP option names.
|
|
*/
|
|
#define IP_FW_IPOPT_LSRR 0x01
|
|
#define IP_FW_IPOPT_SSRR 0x02
|
|
#define IP_FW_IPOPT_RR 0x04
|
|
#define IP_FW_IPOPT_TS 0x08
|
|
|
|
/*
|
|
* Definitions for TCP option names.
|
|
*/
|
|
#define IP_FW_TCPOPT_MSS 0x01
|
|
#define IP_FW_TCPOPT_WINDOW 0x02
|
|
#define IP_FW_TCPOPT_SACK 0x04
|
|
#define IP_FW_TCPOPT_TS 0x08
|
|
#define IP_FW_TCPOPT_CC 0x10
|
|
|
|
/*
|
|
* Main firewall chains definitions and global var's definitions.
|
|
*/
|
|
#ifdef _KERNEL
|
|
|
|
#define IP_FW_PORT_DYNT_FLAG 0x10000
|
|
#define IP_FW_PORT_TEE_FLAG 0x20000
|
|
#define IP_FW_PORT_DENY_FLAG 0x40000
|
|
|
|
/*
|
|
* arguments for calling ip_fw_chk() and dummynet_io(). We put them
|
|
* all into a structure because this way it is easier and more
|
|
* efficient to pass variables around and extend the interface.
|
|
*/
|
|
struct ip_fw_args {
|
|
struct mbuf *m; /* the mbuf chain */
|
|
struct ifnet *oif; /* output interface */
|
|
struct sockaddr_in *next_hop; /* forward address */
|
|
struct ip_fw *rule; /* matching rule */
|
|
struct ether_header *eh; /* for bridged packets */
|
|
|
|
struct route *ro; /* for dummynet */
|
|
struct sockaddr_in *dst; /* for dummynet */
|
|
int flags; /* for dummynet */
|
|
|
|
struct ipfw_flow_id f_id; /* grabbed from IP header */
|
|
u_int16_t divert_rule; /* divert cookie */
|
|
u_int32_t retval;
|
|
};
|
|
|
|
/*
|
|
* Function definitions.
|
|
*/
|
|
void ip_fw_init(void);
|
|
|
|
/* Firewall hooks */
|
|
struct ip;
|
|
struct sockopt;
|
|
typedef int ip_fw_chk_t (struct ip_fw_args *args);
|
|
typedef int ip_fw_ctl_t (struct sockopt *);
|
|
extern ip_fw_chk_t *ip_fw_chk_ptr;
|
|
extern ip_fw_ctl_t *ip_fw_ctl_ptr;
|
|
extern int fw_one_pass;
|
|
extern int fw_enable;
|
|
#define IPFW_LOADED (ip_fw_chk_ptr != NULL)
|
|
#endif /* _KERNEL */
|
|
|
|
#endif /* _IP_FW_H */
|