2004-06-16 23:03:14 +00:00
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/* $OpenBSD: pf_norm.c,v 1.80 2004/03/09 21:44:41 mcbride Exp $ */
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2004-02-26 02:04:28 +00:00
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/*
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* Copyright 2001 Niels Provos <provos@citi.umich.edu>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "pflog.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/filio.h>
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#include <sys/fcntl.h>
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#include <sys/socket.h>
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#include <sys/kernel.h>
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#include <sys/time.h>
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#include <sys/pool.h>
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#include <dev/rndvar.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/bpf.h>
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#include <net/route.h>
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#include <net/if_pflog.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/udp.h>
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#include <netinet/ip_icmp.h>
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#ifdef INET6
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#include <netinet/ip6.h>
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#endif /* INET6 */
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#include <net/pfvar.h>
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struct pf_frent {
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LIST_ENTRY(pf_frent) fr_next;
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struct ip *fr_ip;
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struct mbuf *fr_m;
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};
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struct pf_frcache {
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LIST_ENTRY(pf_frcache) fr_next;
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uint16_t fr_off;
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uint16_t fr_end;
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};
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#define PFFRAG_SEENLAST 0x0001 /* Seen the last fragment for this */
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#define PFFRAG_NOBUFFER 0x0002 /* Non-buffering fragment cache */
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#define PFFRAG_DROP 0x0004 /* Drop all fragments */
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#define BUFFER_FRAGMENTS(fr) (!((fr)->fr_flags & PFFRAG_NOBUFFER))
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struct pf_fragment {
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RB_ENTRY(pf_fragment) fr_entry;
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TAILQ_ENTRY(pf_fragment) frag_next;
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struct in_addr fr_src;
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struct in_addr fr_dst;
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u_int8_t fr_p; /* protocol of this fragment */
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u_int8_t fr_flags; /* status flags */
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u_int16_t fr_id; /* fragment id for reassemble */
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u_int16_t fr_max; /* fragment data max */
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u_int32_t fr_timeout;
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#define fr_queue fr_u.fru_queue
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#define fr_cache fr_u.fru_cache
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union {
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LIST_HEAD(pf_fragq, pf_frent) fru_queue; /* buffering */
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LIST_HEAD(pf_cacheq, pf_frcache) fru_cache; /* non-buf */
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} fr_u;
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};
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TAILQ_HEAD(pf_fragqueue, pf_fragment) pf_fragqueue;
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TAILQ_HEAD(pf_cachequeue, pf_fragment) pf_cachequeue;
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static __inline int pf_frag_compare(struct pf_fragment *,
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struct pf_fragment *);
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RB_HEAD(pf_frag_tree, pf_fragment) pf_frag_tree, pf_cache_tree;
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RB_PROTOTYPE(pf_frag_tree, pf_fragment, fr_entry, pf_frag_compare);
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RB_GENERATE(pf_frag_tree, pf_fragment, fr_entry, pf_frag_compare);
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/* Private prototypes */
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void pf_ip2key(struct pf_fragment *, struct ip *);
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void pf_remove_fragment(struct pf_fragment *);
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void pf_flush_fragments(void);
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void pf_free_fragment(struct pf_fragment *);
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struct pf_fragment *pf_find_fragment(struct ip *, struct pf_frag_tree *);
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struct mbuf *pf_reassemble(struct mbuf **, struct pf_fragment **,
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struct pf_frent *, int);
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struct mbuf *pf_fragcache(struct mbuf **, struct ip*,
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struct pf_fragment **, int, int, int *);
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u_int16_t pf_cksum_fixup(u_int16_t, u_int16_t, u_int16_t);
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int pf_normalize_tcpopt(struct pf_rule *, struct mbuf *,
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struct tcphdr *, int);
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#define DPFPRINTF(x) if (pf_status.debug >= PF_DEBUG_MISC) \
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{ printf("%s: ", __func__); printf x ;}
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/* Globals */
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struct pool pf_frent_pl, pf_frag_pl, pf_cache_pl, pf_cent_pl;
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struct pool pf_state_scrub_pl;
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int pf_nfrents, pf_ncache;
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void
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pf_normalize_init(void)
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{
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pool_init(&pf_frent_pl, sizeof(struct pf_frent), 0, 0, 0, "pffrent",
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NULL);
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pool_init(&pf_frag_pl, sizeof(struct pf_fragment), 0, 0, 0, "pffrag",
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NULL);
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pool_init(&pf_cache_pl, sizeof(struct pf_fragment), 0, 0, 0,
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"pffrcache", NULL);
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pool_init(&pf_cent_pl, sizeof(struct pf_frcache), 0, 0, 0, "pffrcent",
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NULL);
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pool_init(&pf_state_scrub_pl, sizeof(struct pf_state_scrub), 0, 0, 0,
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"pfstscr", NULL);
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pool_sethiwat(&pf_frag_pl, PFFRAG_FRAG_HIWAT);
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pool_sethardlimit(&pf_frent_pl, PFFRAG_FRENT_HIWAT, NULL, 0);
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pool_sethardlimit(&pf_cache_pl, PFFRAG_FRCACHE_HIWAT, NULL, 0);
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pool_sethardlimit(&pf_cent_pl, PFFRAG_FRCENT_HIWAT, NULL, 0);
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TAILQ_INIT(&pf_fragqueue);
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TAILQ_INIT(&pf_cachequeue);
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}
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static __inline int
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pf_frag_compare(struct pf_fragment *a, struct pf_fragment *b)
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{
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int diff;
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if ((diff = a->fr_id - b->fr_id))
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return (diff);
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else if ((diff = a->fr_p - b->fr_p))
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return (diff);
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else if (a->fr_src.s_addr < b->fr_src.s_addr)
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return (-1);
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else if (a->fr_src.s_addr > b->fr_src.s_addr)
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return (1);
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else if (a->fr_dst.s_addr < b->fr_dst.s_addr)
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return (-1);
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else if (a->fr_dst.s_addr > b->fr_dst.s_addr)
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return (1);
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return (0);
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}
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void
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pf_purge_expired_fragments(void)
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{
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struct pf_fragment *frag;
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u_int32_t expire = time.tv_sec -
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pf_default_rule.timeout[PFTM_FRAG];
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while ((frag = TAILQ_LAST(&pf_fragqueue, pf_fragqueue)) != NULL) {
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KASSERT(BUFFER_FRAGMENTS(frag));
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if (frag->fr_timeout > expire)
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break;
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DPFPRINTF(("expiring %d(%p)\n", frag->fr_id, frag));
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pf_free_fragment(frag);
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}
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while ((frag = TAILQ_LAST(&pf_cachequeue, pf_cachequeue)) != NULL) {
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KASSERT(!BUFFER_FRAGMENTS(frag));
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if (frag->fr_timeout > expire)
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break;
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DPFPRINTF(("expiring %d(%p)\n", frag->fr_id, frag));
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pf_free_fragment(frag);
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KASSERT(TAILQ_EMPTY(&pf_cachequeue) ||
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TAILQ_LAST(&pf_cachequeue, pf_cachequeue) != frag);
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}
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}
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/*
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* Try to flush old fragments to make space for new ones
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*/
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void
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pf_flush_fragments(void)
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{
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struct pf_fragment *frag;
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int goal;
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goal = pf_nfrents * 9 / 10;
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DPFPRINTF(("trying to free > %d frents\n",
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pf_nfrents - goal));
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while (goal < pf_nfrents) {
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frag = TAILQ_LAST(&pf_fragqueue, pf_fragqueue);
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if (frag == NULL)
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break;
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pf_free_fragment(frag);
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}
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goal = pf_ncache * 9 / 10;
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DPFPRINTF(("trying to free > %d cache entries\n",
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pf_ncache - goal));
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while (goal < pf_ncache) {
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frag = TAILQ_LAST(&pf_cachequeue, pf_cachequeue);
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if (frag == NULL)
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break;
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pf_free_fragment(frag);
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}
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}
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/* Frees the fragments and all associated entries */
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void
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pf_free_fragment(struct pf_fragment *frag)
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{
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struct pf_frent *frent;
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struct pf_frcache *frcache;
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/* Free all fragments */
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if (BUFFER_FRAGMENTS(frag)) {
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for (frent = LIST_FIRST(&frag->fr_queue); frent;
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frent = LIST_FIRST(&frag->fr_queue)) {
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LIST_REMOVE(frent, fr_next);
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m_freem(frent->fr_m);
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pool_put(&pf_frent_pl, frent);
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pf_nfrents--;
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}
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} else {
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for (frcache = LIST_FIRST(&frag->fr_cache); frcache;
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frcache = LIST_FIRST(&frag->fr_cache)) {
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LIST_REMOVE(frcache, fr_next);
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KASSERT(LIST_EMPTY(&frag->fr_cache) ||
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LIST_FIRST(&frag->fr_cache)->fr_off >
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frcache->fr_end);
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pool_put(&pf_cent_pl, frcache);
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pf_ncache--;
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}
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}
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pf_remove_fragment(frag);
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}
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void
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pf_ip2key(struct pf_fragment *key, struct ip *ip)
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{
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key->fr_p = ip->ip_p;
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key->fr_id = ip->ip_id;
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key->fr_src.s_addr = ip->ip_src.s_addr;
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key->fr_dst.s_addr = ip->ip_dst.s_addr;
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}
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struct pf_fragment *
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pf_find_fragment(struct ip *ip, struct pf_frag_tree *tree)
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{
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struct pf_fragment key;
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struct pf_fragment *frag;
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pf_ip2key(&key, ip);
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frag = RB_FIND(pf_frag_tree, tree, &key);
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if (frag != NULL) {
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/* XXX Are we sure we want to update the timeout? */
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frag->fr_timeout = time.tv_sec;
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if (BUFFER_FRAGMENTS(frag)) {
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TAILQ_REMOVE(&pf_fragqueue, frag, frag_next);
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TAILQ_INSERT_HEAD(&pf_fragqueue, frag, frag_next);
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} else {
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TAILQ_REMOVE(&pf_cachequeue, frag, frag_next);
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TAILQ_INSERT_HEAD(&pf_cachequeue, frag, frag_next);
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}
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}
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return (frag);
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}
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/* Removes a fragment from the fragment queue and frees the fragment */
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void
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pf_remove_fragment(struct pf_fragment *frag)
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{
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if (BUFFER_FRAGMENTS(frag)) {
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RB_REMOVE(pf_frag_tree, &pf_frag_tree, frag);
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TAILQ_REMOVE(&pf_fragqueue, frag, frag_next);
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pool_put(&pf_frag_pl, frag);
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} else {
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RB_REMOVE(pf_frag_tree, &pf_cache_tree, frag);
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TAILQ_REMOVE(&pf_cachequeue, frag, frag_next);
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pool_put(&pf_cache_pl, frag);
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}
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}
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#define FR_IP_OFF(fr) ((ntohs((fr)->fr_ip->ip_off) & IP_OFFMASK) << 3)
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struct mbuf *
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pf_reassemble(struct mbuf **m0, struct pf_fragment **frag,
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struct pf_frent *frent, int mff)
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{
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struct mbuf *m = *m0, *m2;
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struct pf_frent *frea, *next;
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struct pf_frent *frep = NULL;
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struct ip *ip = frent->fr_ip;
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int hlen = ip->ip_hl << 2;
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u_int16_t off = (ntohs(ip->ip_off) & IP_OFFMASK) << 3;
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u_int16_t ip_len = ntohs(ip->ip_len) - ip->ip_hl * 4;
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u_int16_t max = ip_len + off;
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KASSERT(*frag == NULL || BUFFER_FRAGMENTS(*frag));
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/* Strip off ip header */
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m->m_data += hlen;
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m->m_len -= hlen;
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/* Create a new reassembly queue for this packet */
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if (*frag == NULL) {
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*frag = pool_get(&pf_frag_pl, PR_NOWAIT);
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if (*frag == NULL) {
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pf_flush_fragments();
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*frag = pool_get(&pf_frag_pl, PR_NOWAIT);
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if (*frag == NULL)
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goto drop_fragment;
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}
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(*frag)->fr_flags = 0;
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|
|
|
(*frag)->fr_max = 0;
|
|
|
|
(*frag)->fr_src = frent->fr_ip->ip_src;
|
|
|
|
(*frag)->fr_dst = frent->fr_ip->ip_dst;
|
|
|
|
(*frag)->fr_p = frent->fr_ip->ip_p;
|
|
|
|
(*frag)->fr_id = frent->fr_ip->ip_id;
|
|
|
|
(*frag)->fr_timeout = time.tv_sec;
|
|
|
|
LIST_INIT(&(*frag)->fr_queue);
|
|
|
|
|
|
|
|
RB_INSERT(pf_frag_tree, &pf_frag_tree, *frag);
|
|
|
|
TAILQ_INSERT_HEAD(&pf_fragqueue, *frag, frag_next);
|
|
|
|
|
|
|
|
/* We do not have a previous fragment */
|
|
|
|
frep = NULL;
|
|
|
|
goto insert;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Find a fragment after the current one:
|
|
|
|
* - off contains the real shifted offset.
|
|
|
|
*/
|
|
|
|
LIST_FOREACH(frea, &(*frag)->fr_queue, fr_next) {
|
|
|
|
if (FR_IP_OFF(frea) > off)
|
|
|
|
break;
|
|
|
|
frep = frea;
|
|
|
|
}
|
|
|
|
|
|
|
|
KASSERT(frep != NULL || frea != NULL);
|
|
|
|
|
|
|
|
if (frep != NULL &&
|
|
|
|
FR_IP_OFF(frep) + ntohs(frep->fr_ip->ip_len) - frep->fr_ip->ip_hl *
|
2004-06-16 23:03:14 +00:00
|
|
|
4 > off)
|
2004-02-26 02:04:28 +00:00
|
|
|
{
|
|
|
|
u_int16_t precut;
|
|
|
|
|
|
|
|
precut = FR_IP_OFF(frep) + ntohs(frep->fr_ip->ip_len) -
|
|
|
|
frep->fr_ip->ip_hl * 4 - off;
|
|
|
|
if (precut >= ip_len)
|
|
|
|
goto drop_fragment;
|
|
|
|
m_adj(frent->fr_m, precut);
|
|
|
|
DPFPRINTF(("overlap -%d\n", precut));
|
|
|
|
/* Enforce 8 byte boundaries */
|
|
|
|
ip->ip_off = htons(ntohs(ip->ip_off) + (precut >> 3));
|
|
|
|
off = (ntohs(ip->ip_off) & IP_OFFMASK) << 3;
|
|
|
|
ip_len -= precut;
|
|
|
|
ip->ip_len = htons(ip_len);
|
|
|
|
}
|
|
|
|
|
|
|
|
for (; frea != NULL && ip_len + off > FR_IP_OFF(frea);
|
|
|
|
frea = next)
|
|
|
|
{
|
|
|
|
u_int16_t aftercut;
|
|
|
|
|
|
|
|
aftercut = ip_len + off - FR_IP_OFF(frea);
|
|
|
|
DPFPRINTF(("adjust overlap %d\n", aftercut));
|
|
|
|
if (aftercut < ntohs(frea->fr_ip->ip_len) - frea->fr_ip->ip_hl
|
|
|
|
* 4)
|
|
|
|
{
|
|
|
|
frea->fr_ip->ip_len =
|
|
|
|
htons(ntohs(frea->fr_ip->ip_len) - aftercut);
|
|
|
|
frea->fr_ip->ip_off = htons(ntohs(frea->fr_ip->ip_off) +
|
|
|
|
(aftercut >> 3));
|
|
|
|
m_adj(frea->fr_m, aftercut);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This fragment is completely overlapped, loose it */
|
|
|
|
next = LIST_NEXT(frea, fr_next);
|
|
|
|
m_freem(frea->fr_m);
|
|
|
|
LIST_REMOVE(frea, fr_next);
|
|
|
|
pool_put(&pf_frent_pl, frea);
|
|
|
|
pf_nfrents--;
|
|
|
|
}
|
|
|
|
|
|
|
|
insert:
|
|
|
|
/* Update maximum data size */
|
|
|
|
if ((*frag)->fr_max < max)
|
|
|
|
(*frag)->fr_max = max;
|
|
|
|
/* This is the last segment */
|
|
|
|
if (!mff)
|
|
|
|
(*frag)->fr_flags |= PFFRAG_SEENLAST;
|
|
|
|
|
|
|
|
if (frep == NULL)
|
|
|
|
LIST_INSERT_HEAD(&(*frag)->fr_queue, frent, fr_next);
|
|
|
|
else
|
|
|
|
LIST_INSERT_AFTER(frep, frent, fr_next);
|
|
|
|
|
|
|
|
/* Check if we are completely reassembled */
|
|
|
|
if (!((*frag)->fr_flags & PFFRAG_SEENLAST))
|
|
|
|
return (NULL);
|
|
|
|
|
|
|
|
/* Check if we have all the data */
|
|
|
|
off = 0;
|
|
|
|
for (frep = LIST_FIRST(&(*frag)->fr_queue); frep; frep = next) {
|
|
|
|
next = LIST_NEXT(frep, fr_next);
|
|
|
|
|
|
|
|
off += ntohs(frep->fr_ip->ip_len) - frep->fr_ip->ip_hl * 4;
|
|
|
|
if (off < (*frag)->fr_max &&
|
|
|
|
(next == NULL || FR_IP_OFF(next) != off))
|
|
|
|
{
|
|
|
|
DPFPRINTF(("missing fragment at %d, next %d, max %d\n",
|
|
|
|
off, next == NULL ? -1 : FR_IP_OFF(next),
|
|
|
|
(*frag)->fr_max));
|
|
|
|
return (NULL);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
DPFPRINTF(("%d < %d?\n", off, (*frag)->fr_max));
|
|
|
|
if (off < (*frag)->fr_max)
|
|
|
|
return (NULL);
|
|
|
|
|
|
|
|
/* We have all the data */
|
|
|
|
frent = LIST_FIRST(&(*frag)->fr_queue);
|
|
|
|
KASSERT(frent != NULL);
|
|
|
|
if ((frent->fr_ip->ip_hl << 2) + off > IP_MAXPACKET) {
|
|
|
|
DPFPRINTF(("drop: too big: %d\n", off));
|
|
|
|
pf_free_fragment(*frag);
|
|
|
|
*frag = NULL;
|
|
|
|
return (NULL);
|
|
|
|
}
|
|
|
|
next = LIST_NEXT(frent, fr_next);
|
|
|
|
|
|
|
|
/* Magic from ip_input */
|
|
|
|
ip = frent->fr_ip;
|
|
|
|
m = frent->fr_m;
|
|
|
|
m2 = m->m_next;
|
|
|
|
m->m_next = NULL;
|
|
|
|
m_cat(m, m2);
|
|
|
|
pool_put(&pf_frent_pl, frent);
|
|
|
|
pf_nfrents--;
|
|
|
|
for (frent = next; frent != NULL; frent = next) {
|
|
|
|
next = LIST_NEXT(frent, fr_next);
|
|
|
|
|
|
|
|
m2 = frent->fr_m;
|
|
|
|
pool_put(&pf_frent_pl, frent);
|
|
|
|
pf_nfrents--;
|
|
|
|
m_cat(m, m2);
|
|
|
|
}
|
|
|
|
|
|
|
|
ip->ip_src = (*frag)->fr_src;
|
|
|
|
ip->ip_dst = (*frag)->fr_dst;
|
|
|
|
|
|
|
|
/* Remove from fragment queue */
|
|
|
|
pf_remove_fragment(*frag);
|
|
|
|
*frag = NULL;
|
|
|
|
|
|
|
|
hlen = ip->ip_hl << 2;
|
|
|
|
ip->ip_len = htons(off + hlen);
|
|
|
|
m->m_len += hlen;
|
|
|
|
m->m_data -= hlen;
|
|
|
|
|
|
|
|
/* some debugging cruft by sklower, below, will go away soon */
|
|
|
|
/* XXX this should be done elsewhere */
|
|
|
|
if (m->m_flags & M_PKTHDR) {
|
|
|
|
int plen = 0;
|
|
|
|
for (m2 = m; m2; m2 = m2->m_next)
|
|
|
|
plen += m2->m_len;
|
|
|
|
m->m_pkthdr.len = plen;
|
|
|
|
}
|
|
|
|
|
|
|
|
DPFPRINTF(("complete: %p(%d)\n", m, ntohs(ip->ip_len)));
|
|
|
|
return (m);
|
|
|
|
|
|
|
|
drop_fragment:
|
|
|
|
/* Oops - fail safe - drop packet */
|
|
|
|
pool_put(&pf_frent_pl, frent);
|
|
|
|
pf_nfrents--;
|
|
|
|
m_freem(m);
|
|
|
|
return (NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
struct mbuf *
|
|
|
|
pf_fragcache(struct mbuf **m0, struct ip *h, struct pf_fragment **frag, int mff,
|
|
|
|
int drop, int *nomem)
|
|
|
|
{
|
|
|
|
struct mbuf *m = *m0;
|
|
|
|
struct pf_frcache *frp, *fra, *cur = NULL;
|
|
|
|
int ip_len = ntohs(h->ip_len) - (h->ip_hl << 2);
|
|
|
|
u_int16_t off = ntohs(h->ip_off) << 3;
|
|
|
|
u_int16_t max = ip_len + off;
|
|
|
|
int hosed = 0;
|
|
|
|
|
|
|
|
KASSERT(*frag == NULL || !BUFFER_FRAGMENTS(*frag));
|
|
|
|
|
|
|
|
/* Create a new range queue for this packet */
|
|
|
|
if (*frag == NULL) {
|
|
|
|
*frag = pool_get(&pf_cache_pl, PR_NOWAIT);
|
|
|
|
if (*frag == NULL) {
|
|
|
|
pf_flush_fragments();
|
|
|
|
*frag = pool_get(&pf_cache_pl, PR_NOWAIT);
|
|
|
|
if (*frag == NULL)
|
|
|
|
goto no_mem;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Get an entry for the queue */
|
|
|
|
cur = pool_get(&pf_cent_pl, PR_NOWAIT);
|
|
|
|
if (cur == NULL) {
|
|
|
|
pool_put(&pf_cache_pl, *frag);
|
|
|
|
*frag = NULL;
|
|
|
|
goto no_mem;
|
|
|
|
}
|
|
|
|
pf_ncache++;
|
|
|
|
|
|
|
|
(*frag)->fr_flags = PFFRAG_NOBUFFER;
|
|
|
|
(*frag)->fr_max = 0;
|
|
|
|
(*frag)->fr_src = h->ip_src;
|
|
|
|
(*frag)->fr_dst = h->ip_dst;
|
|
|
|
(*frag)->fr_p = h->ip_p;
|
|
|
|
(*frag)->fr_id = h->ip_id;
|
|
|
|
(*frag)->fr_timeout = time.tv_sec;
|
|
|
|
|
|
|
|
cur->fr_off = off;
|
|
|
|
cur->fr_end = max;
|
|
|
|
LIST_INIT(&(*frag)->fr_cache);
|
|
|
|
LIST_INSERT_HEAD(&(*frag)->fr_cache, cur, fr_next);
|
|
|
|
|
|
|
|
RB_INSERT(pf_frag_tree, &pf_cache_tree, *frag);
|
|
|
|
TAILQ_INSERT_HEAD(&pf_cachequeue, *frag, frag_next);
|
|
|
|
|
|
|
|
DPFPRINTF(("fragcache[%d]: new %d-%d\n", h->ip_id, off, max));
|
|
|
|
|
|
|
|
goto pass;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Find a fragment after the current one:
|
|
|
|
* - off contains the real shifted offset.
|
|
|
|
*/
|
|
|
|
frp = NULL;
|
|
|
|
LIST_FOREACH(fra, &(*frag)->fr_cache, fr_next) {
|
|
|
|
if (fra->fr_off > off)
|
|
|
|
break;
|
|
|
|
frp = fra;
|
|
|
|
}
|
|
|
|
|
|
|
|
KASSERT(frp != NULL || fra != NULL);
|
|
|
|
|
|
|
|
if (frp != NULL) {
|
|
|
|
int precut;
|
|
|
|
|
|
|
|
precut = frp->fr_end - off;
|
|
|
|
if (precut >= ip_len) {
|
|
|
|
/* Fragment is entirely a duplicate */
|
|
|
|
DPFPRINTF(("fragcache[%d]: dead (%d-%d) %d-%d\n",
|
|
|
|
h->ip_id, frp->fr_off, frp->fr_end, off, max));
|
|
|
|
goto drop_fragment;
|
|
|
|
}
|
|
|
|
if (precut == 0) {
|
|
|
|
/* They are adjacent. Fixup cache entry */
|
|
|
|
DPFPRINTF(("fragcache[%d]: adjacent (%d-%d) %d-%d\n",
|
|
|
|
h->ip_id, frp->fr_off, frp->fr_end, off, max));
|
|
|
|
frp->fr_end = max;
|
|
|
|
} else if (precut > 0) {
|
|
|
|
/* The first part of this payload overlaps with a
|
|
|
|
* fragment that has already been passed.
|
|
|
|
* Need to trim off the first part of the payload.
|
|
|
|
* But to do so easily, we need to create another
|
|
|
|
* mbuf to throw the original header into.
|
|
|
|
*/
|
|
|
|
|
|
|
|
DPFPRINTF(("fragcache[%d]: chop %d (%d-%d) %d-%d\n",
|
|
|
|
h->ip_id, precut, frp->fr_off, frp->fr_end, off,
|
|
|
|
max));
|
|
|
|
|
|
|
|
off += precut;
|
|
|
|
max -= precut;
|
|
|
|
/* Update the previous frag to encompass this one */
|
|
|
|
frp->fr_end = max;
|
|
|
|
|
|
|
|
if (!drop) {
|
|
|
|
/* XXX Optimization opportunity
|
|
|
|
* This is a very heavy way to trim the payload.
|
|
|
|
* we could do it much faster by diddling mbuf
|
|
|
|
* internals but that would be even less legible
|
|
|
|
* than this mbuf magic. For my next trick,
|
|
|
|
* I'll pull a rabbit out of my laptop.
|
|
|
|
*/
|
|
|
|
*m0 = m_copym2(m, 0, h->ip_hl << 2, M_NOWAIT);
|
|
|
|
if (*m0 == NULL)
|
|
|
|
goto no_mem;
|
|
|
|
KASSERT((*m0)->m_next == NULL);
|
|
|
|
m_adj(m, precut + (h->ip_hl << 2));
|
|
|
|
m_cat(*m0, m);
|
|
|
|
m = *m0;
|
|
|
|
if (m->m_flags & M_PKTHDR) {
|
|
|
|
int plen = 0;
|
|
|
|
struct mbuf *t;
|
|
|
|
for (t = m; t; t = t->m_next)
|
|
|
|
plen += t->m_len;
|
|
|
|
m->m_pkthdr.len = plen;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
h = mtod(m, struct ip *);
|
|
|
|
|
|
|
|
|
2004-06-16 23:03:14 +00:00
|
|
|
KASSERT((int)m->m_len ==
|
|
|
|
ntohs(h->ip_len) - precut);
|
|
|
|
h->ip_off = htons(ntohs(h->ip_off) +
|
|
|
|
(precut >> 3));
|
2004-02-26 02:04:28 +00:00
|
|
|
h->ip_len = htons(ntohs(h->ip_len) - precut);
|
|
|
|
} else {
|
|
|
|
hosed++;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
/* There is a gap between fragments */
|
|
|
|
|
|
|
|
DPFPRINTF(("fragcache[%d]: gap %d (%d-%d) %d-%d\n",
|
|
|
|
h->ip_id, -precut, frp->fr_off, frp->fr_end, off,
|
|
|
|
max));
|
|
|
|
|
|
|
|
cur = pool_get(&pf_cent_pl, PR_NOWAIT);
|
|
|
|
if (cur == NULL)
|
|
|
|
goto no_mem;
|
|
|
|
pf_ncache++;
|
|
|
|
|
|
|
|
cur->fr_off = off;
|
|
|
|
cur->fr_end = max;
|
|
|
|
LIST_INSERT_AFTER(frp, cur, fr_next);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (fra != NULL) {
|
|
|
|
int aftercut;
|
|
|
|
int merge = 0;
|
|
|
|
|
|
|
|
aftercut = max - fra->fr_off;
|
|
|
|
if (aftercut == 0) {
|
|
|
|
/* Adjacent fragments */
|
|
|
|
DPFPRINTF(("fragcache[%d]: adjacent %d-%d (%d-%d)\n",
|
|
|
|
h->ip_id, off, max, fra->fr_off, fra->fr_end));
|
|
|
|
fra->fr_off = off;
|
|
|
|
merge = 1;
|
|
|
|
} else if (aftercut > 0) {
|
|
|
|
/* Need to chop off the tail of this fragment */
|
|
|
|
DPFPRINTF(("fragcache[%d]: chop %d %d-%d (%d-%d)\n",
|
|
|
|
h->ip_id, aftercut, off, max, fra->fr_off,
|
|
|
|
fra->fr_end));
|
|
|
|
fra->fr_off = off;
|
|
|
|
max -= aftercut;
|
|
|
|
|
|
|
|
merge = 1;
|
|
|
|
|
|
|
|
if (!drop) {
|
|
|
|
m_adj(m, -aftercut);
|
|
|
|
if (m->m_flags & M_PKTHDR) {
|
|
|
|
int plen = 0;
|
|
|
|
struct mbuf *t;
|
|
|
|
for (t = m; t; t = t->m_next)
|
|
|
|
plen += t->m_len;
|
|
|
|
m->m_pkthdr.len = plen;
|
|
|
|
}
|
|
|
|
h = mtod(m, struct ip *);
|
2004-06-16 23:03:14 +00:00
|
|
|
KASSERT((int)m->m_len ==
|
|
|
|
ntohs(h->ip_len) - aftercut);
|
2004-02-26 02:04:28 +00:00
|
|
|
h->ip_len = htons(ntohs(h->ip_len) - aftercut);
|
|
|
|
} else {
|
|
|
|
hosed++;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
/* There is a gap between fragments */
|
|
|
|
DPFPRINTF(("fragcache[%d]: gap %d %d-%d (%d-%d)\n",
|
|
|
|
h->ip_id, -aftercut, off, max, fra->fr_off,
|
|
|
|
fra->fr_end));
|
|
|
|
|
|
|
|
cur = pool_get(&pf_cent_pl, PR_NOWAIT);
|
|
|
|
if (cur == NULL)
|
|
|
|
goto no_mem;
|
|
|
|
pf_ncache++;
|
|
|
|
|
|
|
|
cur->fr_off = off;
|
|
|
|
cur->fr_end = max;
|
|
|
|
LIST_INSERT_BEFORE(fra, cur, fr_next);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* Need to glue together two separate fragment descriptors */
|
|
|
|
if (merge) {
|
|
|
|
if (cur && fra->fr_off <= cur->fr_end) {
|
|
|
|
/* Need to merge in a previous 'cur' */
|
|
|
|
DPFPRINTF(("fragcache[%d]: adjacent(merge "
|
|
|
|
"%d-%d) %d-%d (%d-%d)\n",
|
|
|
|
h->ip_id, cur->fr_off, cur->fr_end, off,
|
|
|
|
max, fra->fr_off, fra->fr_end));
|
|
|
|
fra->fr_off = cur->fr_off;
|
|
|
|
LIST_REMOVE(cur, fr_next);
|
|
|
|
pool_put(&pf_cent_pl, cur);
|
|
|
|
pf_ncache--;
|
|
|
|
cur = NULL;
|
|
|
|
|
|
|
|
} else if (frp && fra->fr_off <= frp->fr_end) {
|
|
|
|
/* Need to merge in a modified 'frp' */
|
|
|
|
KASSERT(cur == NULL);
|
|
|
|
DPFPRINTF(("fragcache[%d]: adjacent(merge "
|
|
|
|
"%d-%d) %d-%d (%d-%d)\n",
|
|
|
|
h->ip_id, frp->fr_off, frp->fr_end, off,
|
|
|
|
max, fra->fr_off, fra->fr_end));
|
|
|
|
fra->fr_off = frp->fr_off;
|
|
|
|
LIST_REMOVE(frp, fr_next);
|
|
|
|
pool_put(&pf_cent_pl, frp);
|
|
|
|
pf_ncache--;
|
|
|
|
frp = NULL;
|
|
|
|
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (hosed) {
|
|
|
|
/*
|
|
|
|
* We must keep tracking the overall fragment even when
|
|
|
|
* we're going to drop it anyway so that we know when to
|
|
|
|
* free the overall descriptor. Thus we drop the frag late.
|
|
|
|
*/
|
|
|
|
goto drop_fragment;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
pass:
|
|
|
|
/* Update maximum data size */
|
|
|
|
if ((*frag)->fr_max < max)
|
|
|
|
(*frag)->fr_max = max;
|
|
|
|
|
|
|
|
/* This is the last segment */
|
|
|
|
if (!mff)
|
|
|
|
(*frag)->fr_flags |= PFFRAG_SEENLAST;
|
|
|
|
|
|
|
|
/* Check if we are completely reassembled */
|
|
|
|
if (((*frag)->fr_flags & PFFRAG_SEENLAST) &&
|
|
|
|
LIST_FIRST(&(*frag)->fr_cache)->fr_off == 0 &&
|
|
|
|
LIST_FIRST(&(*frag)->fr_cache)->fr_end == (*frag)->fr_max) {
|
|
|
|
/* Remove from fragment queue */
|
|
|
|
DPFPRINTF(("fragcache[%d]: done 0-%d\n", h->ip_id,
|
|
|
|
(*frag)->fr_max));
|
|
|
|
pf_free_fragment(*frag);
|
|
|
|
*frag = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return (m);
|
|
|
|
|
|
|
|
no_mem:
|
|
|
|
*nomem = 1;
|
|
|
|
|
|
|
|
/* Still need to pay attention to !IP_MF */
|
|
|
|
if (!mff && *frag != NULL)
|
|
|
|
(*frag)->fr_flags |= PFFRAG_SEENLAST;
|
|
|
|
|
|
|
|
m_freem(m);
|
|
|
|
return (NULL);
|
|
|
|
|
|
|
|
drop_fragment:
|
|
|
|
|
|
|
|
/* Still need to pay attention to !IP_MF */
|
|
|
|
if (!mff && *frag != NULL)
|
|
|
|
(*frag)->fr_flags |= PFFRAG_SEENLAST;
|
|
|
|
|
|
|
|
if (drop) {
|
|
|
|
/* This fragment has been deemed bad. Don't reass */
|
|
|
|
if (((*frag)->fr_flags & PFFRAG_DROP) == 0)
|
|
|
|
DPFPRINTF(("fragcache[%d]: dropping overall fragment\n",
|
|
|
|
h->ip_id));
|
|
|
|
(*frag)->fr_flags |= PFFRAG_DROP;
|
|
|
|
}
|
|
|
|
|
|
|
|
m_freem(m);
|
|
|
|
return (NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
2004-06-16 23:03:14 +00:00
|
|
|
pf_normalize_ip(struct mbuf **m0, int dir, struct pfi_kif *kif, u_short *reason)
|
2004-02-26 02:04:28 +00:00
|
|
|
{
|
|
|
|
struct mbuf *m = *m0;
|
|
|
|
struct pf_rule *r;
|
|
|
|
struct pf_frent *frent;
|
|
|
|
struct pf_fragment *frag = NULL;
|
|
|
|
struct ip *h = mtod(m, struct ip *);
|
|
|
|
int mff = (ntohs(h->ip_off) & IP_MF);
|
|
|
|
int hlen = h->ip_hl << 2;
|
|
|
|
u_int16_t fragoff = (ntohs(h->ip_off) & IP_OFFMASK) << 3;
|
|
|
|
u_int16_t max;
|
|
|
|
int ip_len;
|
|
|
|
int ip_off;
|
|
|
|
|
|
|
|
r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
|
|
|
|
while (r != NULL) {
|
|
|
|
r->evaluations++;
|
2004-06-16 23:03:14 +00:00
|
|
|
if (r->kif != NULL &&
|
|
|
|
(r->kif != kif && r->kif != kif->pfik_parent) == !r->ifnot)
|
2004-02-26 02:04:28 +00:00
|
|
|
r = r->skip[PF_SKIP_IFP].ptr;
|
|
|
|
else if (r->direction && r->direction != dir)
|
|
|
|
r = r->skip[PF_SKIP_DIR].ptr;
|
|
|
|
else if (r->af && r->af != AF_INET)
|
|
|
|
r = r->skip[PF_SKIP_AF].ptr;
|
|
|
|
else if (r->proto && r->proto != h->ip_p)
|
|
|
|
r = r->skip[PF_SKIP_PROTO].ptr;
|
|
|
|
else if (PF_MISMATCHAW(&r->src.addr,
|
|
|
|
(struct pf_addr *)&h->ip_src.s_addr, AF_INET, r->src.not))
|
|
|
|
r = r->skip[PF_SKIP_SRC_ADDR].ptr;
|
|
|
|
else if (PF_MISMATCHAW(&r->dst.addr,
|
|
|
|
(struct pf_addr *)&h->ip_dst.s_addr, AF_INET, r->dst.not))
|
|
|
|
r = r->skip[PF_SKIP_DST_ADDR].ptr;
|
|
|
|
else
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (r == NULL)
|
|
|
|
return (PF_PASS);
|
|
|
|
else
|
|
|
|
r->packets++;
|
|
|
|
|
|
|
|
/* Check for illegal packets */
|
|
|
|
if (hlen < (int)sizeof(struct ip))
|
|
|
|
goto drop;
|
|
|
|
|
|
|
|
if (hlen > ntohs(h->ip_len))
|
|
|
|
goto drop;
|
|
|
|
|
|
|
|
/* Clear IP_DF if the rule uses the no-df option */
|
|
|
|
if (r->rule_flag & PFRULE_NODF)
|
|
|
|
h->ip_off &= htons(~IP_DF);
|
|
|
|
|
|
|
|
/* We will need other tests here */
|
|
|
|
if (!fragoff && !mff)
|
|
|
|
goto no_fragment;
|
|
|
|
|
|
|
|
/* We're dealing with a fragment now. Don't allow fragments
|
|
|
|
* with IP_DF to enter the cache. If the flag was cleared by
|
|
|
|
* no-df above, fine. Otherwise drop it.
|
|
|
|
*/
|
|
|
|
if (h->ip_off & htons(IP_DF)) {
|
|
|
|
DPFPRINTF(("IP_DF\n"));
|
|
|
|
goto bad;
|
|
|
|
}
|
|
|
|
|
|
|
|
ip_len = ntohs(h->ip_len) - hlen;
|
|
|
|
ip_off = (ntohs(h->ip_off) & IP_OFFMASK) << 3;
|
|
|
|
|
|
|
|
/* All fragments are 8 byte aligned */
|
|
|
|
if (mff && (ip_len & 0x7)) {
|
|
|
|
DPFPRINTF(("mff and %d\n", ip_len));
|
|
|
|
goto bad;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Respect maximum length */
|
|
|
|
if (fragoff + ip_len > IP_MAXPACKET) {
|
|
|
|
DPFPRINTF(("max packet %d\n", fragoff + ip_len));
|
|
|
|
goto bad;
|
|
|
|
}
|
|
|
|
max = fragoff + ip_len;
|
|
|
|
|
|
|
|
if ((r->rule_flag & (PFRULE_FRAGCROP|PFRULE_FRAGDROP)) == 0) {
|
|
|
|
/* Fully buffer all of the fragments */
|
|
|
|
|
|
|
|
frag = pf_find_fragment(h, &pf_frag_tree);
|
|
|
|
|
|
|
|
/* Check if we saw the last fragment already */
|
|
|
|
if (frag != NULL && (frag->fr_flags & PFFRAG_SEENLAST) &&
|
|
|
|
max > frag->fr_max)
|
|
|
|
goto bad;
|
|
|
|
|
|
|
|
/* Get an entry for the fragment queue */
|
|
|
|
frent = pool_get(&pf_frent_pl, PR_NOWAIT);
|
|
|
|
if (frent == NULL) {
|
|
|
|
REASON_SET(reason, PFRES_MEMORY);
|
|
|
|
return (PF_DROP);
|
|
|
|
}
|
|
|
|
pf_nfrents++;
|
|
|
|
frent->fr_ip = h;
|
|
|
|
frent->fr_m = m;
|
|
|
|
|
|
|
|
/* Might return a completely reassembled mbuf, or NULL */
|
|
|
|
DPFPRINTF(("reass frag %d @ %d-%d\n", h->ip_id, fragoff, max));
|
|
|
|
*m0 = m = pf_reassemble(m0, &frag, frent, mff);
|
|
|
|
|
|
|
|
if (m == NULL)
|
|
|
|
return (PF_DROP);
|
|
|
|
|
|
|
|
if (frag != NULL && (frag->fr_flags & PFFRAG_DROP))
|
|
|
|
goto drop;
|
|
|
|
|
|
|
|
h = mtod(m, struct ip *);
|
|
|
|
} else {
|
|
|
|
/* non-buffering fragment cache (drops or masks overlaps) */
|
|
|
|
int nomem = 0;
|
|
|
|
|
|
|
|
if (dir == PF_OUT) {
|
|
|
|
if (m_tag_find(m, PACKET_TAG_PF_FRAGCACHE, NULL) !=
|
|
|
|
NULL) {
|
|
|
|
/* Already passed the fragment cache in the
|
|
|
|
* input direction. If we continued, it would
|
|
|
|
* appear to be a dup and would be dropped.
|
|
|
|
*/
|
|
|
|
goto fragment_pass;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
frag = pf_find_fragment(h, &pf_cache_tree);
|
|
|
|
|
|
|
|
/* Check if we saw the last fragment already */
|
|
|
|
if (frag != NULL && (frag->fr_flags & PFFRAG_SEENLAST) &&
|
|
|
|
max > frag->fr_max) {
|
|
|
|
if (r->rule_flag & PFRULE_FRAGDROP)
|
|
|
|
frag->fr_flags |= PFFRAG_DROP;
|
|
|
|
goto bad;
|
|
|
|
}
|
|
|
|
|
|
|
|
*m0 = m = pf_fragcache(m0, h, &frag, mff,
|
|
|
|
(r->rule_flag & PFRULE_FRAGDROP) ? 1 : 0, &nomem);
|
|
|
|
if (m == NULL) {
|
|
|
|
if (nomem)
|
|
|
|
goto no_mem;
|
|
|
|
goto drop;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (dir == PF_IN) {
|
|
|
|
struct m_tag *mtag;
|
|
|
|
|
|
|
|
mtag = m_tag_get(PACKET_TAG_PF_FRAGCACHE, 0, M_NOWAIT);
|
|
|
|
if (mtag == NULL)
|
|
|
|
goto no_mem;
|
|
|
|
m_tag_prepend(m, mtag);
|
|
|
|
}
|
|
|
|
if (frag != NULL && (frag->fr_flags & PFFRAG_DROP))
|
|
|
|
goto drop;
|
|
|
|
goto fragment_pass;
|
|
|
|
}
|
|
|
|
|
|
|
|
no_fragment:
|
|
|
|
/* At this point, only IP_DF is allowed in ip_off */
|
|
|
|
h->ip_off &= htons(IP_DF);
|
|
|
|
|
|
|
|
/* Enforce a minimum ttl, may cause endless packet loops */
|
|
|
|
if (r->min_ttl && h->ip_ttl < r->min_ttl)
|
|
|
|
h->ip_ttl = r->min_ttl;
|
|
|
|
|
|
|
|
if (r->rule_flag & PFRULE_RANDOMID)
|
|
|
|
h->ip_id = ip_randomid();
|
|
|
|
|
|
|
|
return (PF_PASS);
|
|
|
|
|
|
|
|
fragment_pass:
|
|
|
|
/* Enforce a minimum ttl, may cause endless packet loops */
|
|
|
|
if (r->min_ttl && h->ip_ttl < r->min_ttl)
|
|
|
|
h->ip_ttl = r->min_ttl;
|
|
|
|
|
|
|
|
return (PF_PASS);
|
|
|
|
|
|
|
|
no_mem:
|
|
|
|
REASON_SET(reason, PFRES_MEMORY);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
|
|
|
|
drop:
|
|
|
|
REASON_SET(reason, PFRES_NORM);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
|
|
|
|
bad:
|
|
|
|
DPFPRINTF(("dropping bad fragment\n"));
|
|
|
|
|
|
|
|
/* Free associated fragments */
|
|
|
|
if (frag != NULL)
|
|
|
|
pf_free_fragment(frag);
|
|
|
|
|
|
|
|
REASON_SET(reason, PFRES_FRAG);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
|
|
|
|
return (PF_DROP);
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef INET6
|
|
|
|
int
|
2004-06-16 23:03:14 +00:00
|
|
|
pf_normalize_ip6(struct mbuf **m0, int dir, struct pfi_kif *kif,
|
|
|
|
u_short *reason)
|
2004-02-26 02:04:28 +00:00
|
|
|
{
|
|
|
|
struct mbuf *m = *m0;
|
|
|
|
struct pf_rule *r;
|
|
|
|
struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
|
|
|
|
int off;
|
|
|
|
struct ip6_ext ext;
|
|
|
|
struct ip6_opt opt;
|
|
|
|
struct ip6_opt_jumbo jumbo;
|
|
|
|
struct ip6_frag frag;
|
|
|
|
u_int32_t jumbolen = 0, plen;
|
|
|
|
u_int16_t fragoff = 0;
|
|
|
|
int optend;
|
|
|
|
int ooff;
|
|
|
|
u_int8_t proto;
|
|
|
|
int terminal;
|
|
|
|
|
|
|
|
r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
|
|
|
|
while (r != NULL) {
|
|
|
|
r->evaluations++;
|
2004-06-16 23:03:14 +00:00
|
|
|
if (r->kif != NULL &&
|
|
|
|
(r->kif != kif && r->kif != kif->pfik_parent) == !r->ifnot)
|
2004-02-26 02:04:28 +00:00
|
|
|
r = r->skip[PF_SKIP_IFP].ptr;
|
|
|
|
else if (r->direction && r->direction != dir)
|
|
|
|
r = r->skip[PF_SKIP_DIR].ptr;
|
|
|
|
else if (r->af && r->af != AF_INET6)
|
|
|
|
r = r->skip[PF_SKIP_AF].ptr;
|
|
|
|
#if 0 /* header chain! */
|
|
|
|
else if (r->proto && r->proto != h->ip6_nxt)
|
|
|
|
r = r->skip[PF_SKIP_PROTO].ptr;
|
|
|
|
#endif
|
|
|
|
else if (PF_MISMATCHAW(&r->src.addr,
|
|
|
|
(struct pf_addr *)&h->ip6_src, AF_INET6, r->src.not))
|
|
|
|
r = r->skip[PF_SKIP_SRC_ADDR].ptr;
|
|
|
|
else if (PF_MISMATCHAW(&r->dst.addr,
|
|
|
|
(struct pf_addr *)&h->ip6_dst, AF_INET6, r->dst.not))
|
|
|
|
r = r->skip[PF_SKIP_DST_ADDR].ptr;
|
|
|
|
else
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (r == NULL)
|
|
|
|
return (PF_PASS);
|
|
|
|
else
|
|
|
|
r->packets++;
|
|
|
|
|
|
|
|
/* Check for illegal packets */
|
|
|
|
if (sizeof(struct ip6_hdr) + IPV6_MAXPACKET < m->m_pkthdr.len)
|
|
|
|
goto drop;
|
|
|
|
|
|
|
|
off = sizeof(struct ip6_hdr);
|
|
|
|
proto = h->ip6_nxt;
|
|
|
|
terminal = 0;
|
|
|
|
do {
|
|
|
|
switch (proto) {
|
|
|
|
case IPPROTO_FRAGMENT:
|
|
|
|
goto fragment;
|
|
|
|
break;
|
|
|
|
case IPPROTO_AH:
|
|
|
|
case IPPROTO_ROUTING:
|
|
|
|
case IPPROTO_DSTOPTS:
|
|
|
|
if (!pf_pull_hdr(m, off, &ext, sizeof(ext), NULL,
|
|
|
|
NULL, AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
if (proto == IPPROTO_AH)
|
|
|
|
off += (ext.ip6e_len + 2) * 4;
|
|
|
|
else
|
|
|
|
off += (ext.ip6e_len + 1) * 8;
|
|
|
|
proto = ext.ip6e_nxt;
|
|
|
|
break;
|
|
|
|
case IPPROTO_HOPOPTS:
|
|
|
|
if (!pf_pull_hdr(m, off, &ext, sizeof(ext), NULL,
|
|
|
|
NULL, AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
optend = off + (ext.ip6e_len + 1) * 8;
|
|
|
|
ooff = off + sizeof(ext);
|
|
|
|
do {
|
|
|
|
if (!pf_pull_hdr(m, ooff, &opt.ip6o_type,
|
|
|
|
sizeof(opt.ip6o_type), NULL, NULL,
|
|
|
|
AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
if (opt.ip6o_type == IP6OPT_PAD1) {
|
|
|
|
ooff++;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
if (!pf_pull_hdr(m, ooff, &opt, sizeof(opt),
|
|
|
|
NULL, NULL, AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
if (ooff + sizeof(opt) + opt.ip6o_len > optend)
|
|
|
|
goto drop;
|
|
|
|
switch (opt.ip6o_type) {
|
|
|
|
case IP6OPT_JUMBO:
|
|
|
|
if (h->ip6_plen != 0)
|
|
|
|
goto drop;
|
|
|
|
if (!pf_pull_hdr(m, ooff, &jumbo,
|
|
|
|
sizeof(jumbo), NULL, NULL,
|
|
|
|
AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
memcpy(&jumbolen, jumbo.ip6oj_jumbo_len,
|
|
|
|
sizeof(jumbolen));
|
|
|
|
jumbolen = ntohl(jumbolen);
|
|
|
|
if (jumbolen <= IPV6_MAXPACKET)
|
|
|
|
goto drop;
|
|
|
|
if (sizeof(struct ip6_hdr) + jumbolen !=
|
|
|
|
m->m_pkthdr.len)
|
|
|
|
goto drop;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
ooff += sizeof(opt) + opt.ip6o_len;
|
|
|
|
} while (ooff < optend);
|
|
|
|
|
|
|
|
off = optend;
|
|
|
|
proto = ext.ip6e_nxt;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
terminal = 1;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
} while (!terminal);
|
|
|
|
|
|
|
|
/* jumbo payload option must be present, or plen > 0 */
|
|
|
|
if (ntohs(h->ip6_plen) == 0)
|
|
|
|
plen = jumbolen;
|
|
|
|
else
|
|
|
|
plen = ntohs(h->ip6_plen);
|
|
|
|
if (plen == 0)
|
|
|
|
goto drop;
|
|
|
|
if (sizeof(struct ip6_hdr) + plen > m->m_pkthdr.len)
|
|
|
|
goto shortpkt;
|
|
|
|
|
|
|
|
/* Enforce a minimum ttl, may cause endless packet loops */
|
|
|
|
if (r->min_ttl && h->ip6_hlim < r->min_ttl)
|
|
|
|
h->ip6_hlim = r->min_ttl;
|
|
|
|
|
|
|
|
return (PF_PASS);
|
|
|
|
|
|
|
|
fragment:
|
|
|
|
if (ntohs(h->ip6_plen) == 0 || jumbolen)
|
|
|
|
goto drop;
|
|
|
|
plen = ntohs(h->ip6_plen);
|
|
|
|
|
|
|
|
if (!pf_pull_hdr(m, off, &frag, sizeof(frag), NULL, NULL, AF_INET6))
|
|
|
|
goto shortpkt;
|
|
|
|
fragoff = ntohs(frag.ip6f_offlg & IP6F_OFF_MASK);
|
|
|
|
if (fragoff + (plen - off - sizeof(frag)) > IPV6_MAXPACKET)
|
|
|
|
goto badfrag;
|
|
|
|
|
|
|
|
/* do something about it */
|
|
|
|
return (PF_PASS);
|
|
|
|
|
|
|
|
shortpkt:
|
|
|
|
REASON_SET(reason, PFRES_SHORT);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
|
|
|
|
drop:
|
|
|
|
REASON_SET(reason, PFRES_NORM);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
|
|
|
|
badfrag:
|
|
|
|
REASON_SET(reason, PFRES_FRAG);
|
|
|
|
if (r != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET6, dir, *reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
int
|
2004-06-16 23:03:14 +00:00
|
|
|
pf_normalize_tcp(int dir, struct pfi_kif *kif, struct mbuf *m, int ipoff,
|
2004-02-26 02:04:28 +00:00
|
|
|
int off, void *h, struct pf_pdesc *pd)
|
|
|
|
{
|
|
|
|
struct pf_rule *r, *rm = NULL;
|
|
|
|
struct tcphdr *th = pd->hdr.tcp;
|
|
|
|
int rewrite = 0;
|
|
|
|
u_short reason;
|
|
|
|
u_int8_t flags;
|
|
|
|
sa_family_t af = pd->af;
|
|
|
|
|
|
|
|
r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);
|
|
|
|
while (r != NULL) {
|
|
|
|
r->evaluations++;
|
2004-06-16 23:03:14 +00:00
|
|
|
if (r->kif != NULL &&
|
|
|
|
(r->kif != kif && r->kif != kif->pfik_parent) == !r->ifnot)
|
2004-02-26 02:04:28 +00:00
|
|
|
r = r->skip[PF_SKIP_IFP].ptr;
|
|
|
|
else if (r->direction && r->direction != dir)
|
|
|
|
r = r->skip[PF_SKIP_DIR].ptr;
|
|
|
|
else if (r->af && r->af != af)
|
|
|
|
r = r->skip[PF_SKIP_AF].ptr;
|
|
|
|
else if (r->proto && r->proto != pd->proto)
|
|
|
|
r = r->skip[PF_SKIP_PROTO].ptr;
|
|
|
|
else if (PF_MISMATCHAW(&r->src.addr, pd->src, af, r->src.not))
|
|
|
|
r = r->skip[PF_SKIP_SRC_ADDR].ptr;
|
|
|
|
else if (r->src.port_op && !pf_match_port(r->src.port_op,
|
|
|
|
r->src.port[0], r->src.port[1], th->th_sport))
|
|
|
|
r = r->skip[PF_SKIP_SRC_PORT].ptr;
|
|
|
|
else if (PF_MISMATCHAW(&r->dst.addr, pd->dst, af, r->dst.not))
|
|
|
|
r = r->skip[PF_SKIP_DST_ADDR].ptr;
|
|
|
|
else if (r->dst.port_op && !pf_match_port(r->dst.port_op,
|
|
|
|
r->dst.port[0], r->dst.port[1], th->th_dport))
|
|
|
|
r = r->skip[PF_SKIP_DST_PORT].ptr;
|
|
|
|
else if (r->os_fingerprint != PF_OSFP_ANY && !pf_osfp_match(
|
|
|
|
pf_osfp_fingerprint(pd, m, off, th),
|
|
|
|
r->os_fingerprint))
|
|
|
|
r = TAILQ_NEXT(r, entries);
|
|
|
|
else {
|
|
|
|
rm = r;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (rm == NULL)
|
|
|
|
return (PF_PASS);
|
|
|
|
else
|
|
|
|
r->packets++;
|
|
|
|
|
|
|
|
if (rm->rule_flag & PFRULE_REASSEMBLE_TCP)
|
|
|
|
pd->flags |= PFDESC_TCP_NORM;
|
|
|
|
|
|
|
|
flags = th->th_flags;
|
|
|
|
if (flags & TH_SYN) {
|
|
|
|
/* Illegal packet */
|
|
|
|
if (flags & TH_RST)
|
|
|
|
goto tcp_drop;
|
|
|
|
|
|
|
|
if (flags & TH_FIN)
|
|
|
|
flags &= ~TH_FIN;
|
|
|
|
} else {
|
|
|
|
/* Illegal packet */
|
|
|
|
if (!(flags & (TH_ACK|TH_RST)))
|
|
|
|
goto tcp_drop;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!(flags & TH_ACK)) {
|
|
|
|
/* These flags are only valid if ACK is set */
|
|
|
|
if ((flags & TH_FIN) || (flags & TH_PUSH) || (flags & TH_URG))
|
|
|
|
goto tcp_drop;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check for illegal header length */
|
|
|
|
if (th->th_off < (sizeof(struct tcphdr) >> 2))
|
|
|
|
goto tcp_drop;
|
|
|
|
|
|
|
|
/* If flags changed, or reserved data set, then adjust */
|
|
|
|
if (flags != th->th_flags || th->th_x2 != 0) {
|
|
|
|
u_int16_t ov, nv;
|
|
|
|
|
|
|
|
ov = *(u_int16_t *)(&th->th_ack + 1);
|
|
|
|
th->th_flags = flags;
|
|
|
|
th->th_x2 = 0;
|
|
|
|
nv = *(u_int16_t *)(&th->th_ack + 1);
|
|
|
|
|
|
|
|
th->th_sum = pf_cksum_fixup(th->th_sum, ov, nv);
|
|
|
|
rewrite = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Remove urgent pointer, if TH_URG is not set */
|
|
|
|
if (!(flags & TH_URG) && th->th_urp) {
|
|
|
|
th->th_sum = pf_cksum_fixup(th->th_sum, th->th_urp, 0);
|
|
|
|
th->th_urp = 0;
|
|
|
|
rewrite = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Process options */
|
|
|
|
if (r->max_mss && pf_normalize_tcpopt(r, m, th, off))
|
|
|
|
rewrite = 1;
|
|
|
|
|
|
|
|
/* copy back packet headers if we sanitized */
|
|
|
|
if (rewrite)
|
|
|
|
m_copyback(m, off, sizeof(*th), th);
|
|
|
|
|
|
|
|
return (PF_PASS);
|
|
|
|
|
|
|
|
tcp_drop:
|
|
|
|
REASON_SET(&reason, PFRES_NORM);
|
|
|
|
if (rm != NULL && r->log)
|
2004-06-16 23:03:14 +00:00
|
|
|
PFLOG_PACKET(kif, h, m, AF_INET, dir, reason, r, NULL, NULL);
|
2004-02-26 02:04:28 +00:00
|
|
|
return (PF_DROP);
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
|
|
|
pf_normalize_tcp_init(struct mbuf *m, int off, struct pf_pdesc *pd,
|
|
|
|
struct tcphdr *th, struct pf_state_peer *src, struct pf_state_peer *dst)
|
|
|
|
{
|
|
|
|
u_int8_t hdr[60];
|
|
|
|
u_int8_t *opt;
|
|
|
|
|
|
|
|
KASSERT(src->scrub == NULL);
|
|
|
|
|
|
|
|
src->scrub = pool_get(&pf_state_scrub_pl, PR_NOWAIT);
|
|
|
|
if (src->scrub == NULL)
|
|
|
|
return (1);
|
|
|
|
bzero(src->scrub, sizeof(*src->scrub));
|
|
|
|
|
|
|
|
switch (pd->af) {
|
|
|
|
#ifdef INET
|
|
|
|
case AF_INET: {
|
|
|
|
struct ip *h = mtod(m, struct ip *);
|
|
|
|
src->scrub->pfss_ttl = h->ip_ttl;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
#endif /* INET */
|
|
|
|
#ifdef INET6
|
|
|
|
case AF_INET6: {
|
|
|
|
struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
|
|
|
|
src->scrub->pfss_ttl = h->ip6_hlim;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
#endif /* INET6 */
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* All normalizations below are only begun if we see the start of
|
|
|
|
* the connections. They must all set an enabled bit in pfss_flags
|
|
|
|
*/
|
|
|
|
if ((th->th_flags & TH_SYN) == 0)
|
2004-06-16 23:03:14 +00:00
|
|
|
return (0);
|
2004-02-26 02:04:28 +00:00
|
|
|
|
|
|
|
|
|
|
|
if (th->th_off > (sizeof(struct tcphdr) >> 2) && src->scrub &&
|
|
|
|
pf_pull_hdr(m, off, hdr, th->th_off << 2, NULL, NULL, pd->af)) {
|
|
|
|
/* Diddle with TCP options */
|
|
|
|
int hlen;
|
|
|
|
opt = hdr + sizeof(struct tcphdr);
|
|
|
|
hlen = (th->th_off << 2) - sizeof(struct tcphdr);
|
|
|
|
while (hlen >= TCPOLEN_TIMESTAMP) {
|
|
|
|
switch (*opt) {
|
|
|
|
case TCPOPT_EOL: /* FALLTHROUGH */
|
|
|
|
case TCPOPT_NOP:
|
|
|
|
opt++;
|
|
|
|
hlen--;
|
|
|
|
break;
|
|
|
|
case TCPOPT_TIMESTAMP:
|
|
|
|
if (opt[1] >= TCPOLEN_TIMESTAMP) {
|
|
|
|
src->scrub->pfss_flags |=
|
|
|
|
PFSS_TIMESTAMP;
|
|
|
|
src->scrub->pfss_ts_mod = arc4random();
|
|
|
|
}
|
|
|
|
/* FALLTHROUGH */
|
|
|
|
default:
|
2004-06-16 23:03:14 +00:00
|
|
|
hlen -= opt[1];
|
|
|
|
opt += opt[1];
|
2004-02-26 02:04:28 +00:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return (0);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
pf_normalize_tcp_cleanup(struct pf_state *state)
|
|
|
|
{
|
|
|
|
if (state->src.scrub)
|
|
|
|
pool_put(&pf_state_scrub_pl, state->src.scrub);
|
|
|
|
if (state->dst.scrub)
|
|
|
|
pool_put(&pf_state_scrub_pl, state->dst.scrub);
|
|
|
|
|
|
|
|
/* Someday... flush the TCP segment reassembly descriptors. */
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
|
|
|
pf_normalize_tcp_stateful(struct mbuf *m, int off, struct pf_pdesc *pd,
|
|
|
|
u_short *reason, struct tcphdr *th, struct pf_state_peer *src,
|
|
|
|
struct pf_state_peer *dst, int *writeback)
|
|
|
|
{
|
|
|
|
u_int8_t hdr[60];
|
|
|
|
u_int8_t *opt;
|
|
|
|
int copyback = 0;
|
|
|
|
|
|
|
|
KASSERT(src->scrub || dst->scrub);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Enforce the minimum TTL seen for this connection. Negate a common
|
|
|
|
* technique to evade an intrusion detection system and confuse
|
|
|
|
* firewall state code.
|
|
|
|
*/
|
|
|
|
switch (pd->af) {
|
|
|
|
#ifdef INET
|
|
|
|
case AF_INET: {
|
|
|
|
if (src->scrub) {
|
|
|
|
struct ip *h = mtod(m, struct ip *);
|
|
|
|
if (h->ip_ttl > src->scrub->pfss_ttl)
|
|
|
|
src->scrub->pfss_ttl = h->ip_ttl;
|
|
|
|
h->ip_ttl = src->scrub->pfss_ttl;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
#endif /* INET */
|
|
|
|
#ifdef INET6
|
|
|
|
case AF_INET6: {
|
2004-06-16 23:03:14 +00:00
|
|
|
if (src->scrub) {
|
2004-02-26 02:04:28 +00:00
|
|
|
struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
|
|
|
|
if (h->ip6_hlim > src->scrub->pfss_ttl)
|
|
|
|
src->scrub->pfss_ttl = h->ip6_hlim;
|
|
|
|
h->ip6_hlim = src->scrub->pfss_ttl;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
#endif /* INET6 */
|
|
|
|
}
|
|
|
|
|
|
|
|
if (th->th_off > (sizeof(struct tcphdr) >> 2) &&
|
|
|
|
((src->scrub && (src->scrub->pfss_flags & PFSS_TIMESTAMP)) ||
|
|
|
|
(dst->scrub && (dst->scrub->pfss_flags & PFSS_TIMESTAMP))) &&
|
|
|
|
pf_pull_hdr(m, off, hdr, th->th_off << 2, NULL, NULL, pd->af)) {
|
|
|
|
/* Diddle with TCP options */
|
|
|
|
int hlen;
|
|
|
|
opt = hdr + sizeof(struct tcphdr);
|
|
|
|
hlen = (th->th_off << 2) - sizeof(struct tcphdr);
|
|
|
|
while (hlen >= TCPOLEN_TIMESTAMP) {
|
|
|
|
switch (*opt) {
|
|
|
|
case TCPOPT_EOL: /* FALLTHROUGH */
|
|
|
|
case TCPOPT_NOP:
|
|
|
|
opt++;
|
|
|
|
hlen--;
|
|
|
|
break;
|
|
|
|
case TCPOPT_TIMESTAMP:
|
|
|
|
/* Modulate the timestamps. Can be used for
|
|
|
|
* NAT detection, OS uptime determination or
|
|
|
|
* reboot detection.
|
|
|
|
*/
|
|
|
|
if (opt[1] >= TCPOLEN_TIMESTAMP) {
|
|
|
|
u_int32_t ts_value;
|
|
|
|
if (src->scrub &&
|
|
|
|
(src->scrub->pfss_flags &
|
|
|
|
PFSS_TIMESTAMP)) {
|
|
|
|
memcpy(&ts_value, &opt[2],
|
|
|
|
sizeof(u_int32_t));
|
|
|
|
ts_value = htonl(ntohl(ts_value)
|
|
|
|
+ src->scrub->pfss_ts_mod);
|
|
|
|
pf_change_a(&opt[2],
|
|
|
|
&th->th_sum, ts_value, 0);
|
|
|
|
copyback = 1;
|
|
|
|
}
|
2004-06-16 23:03:14 +00:00
|
|
|
|
|
|
|
/* Modulate TS reply iff valid (!0) */
|
|
|
|
memcpy(&ts_value, &opt[6],
|
|
|
|
sizeof(u_int32_t));
|
|
|
|
if (ts_value && dst->scrub &&
|
2004-02-26 02:04:28 +00:00
|
|
|
(dst->scrub->pfss_flags &
|
|
|
|
PFSS_TIMESTAMP)) {
|
|
|
|
ts_value = htonl(ntohl(ts_value)
|
|
|
|
- dst->scrub->pfss_ts_mod);
|
|
|
|
pf_change_a(&opt[6],
|
|
|
|
&th->th_sum, ts_value, 0);
|
|
|
|
copyback = 1;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
/* FALLTHROUGH */
|
|
|
|
default:
|
2004-06-16 23:03:14 +00:00
|
|
|
hlen -= opt[1];
|
|
|
|
opt += opt[1];
|
2004-02-26 02:04:28 +00:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (copyback) {
|
|
|
|
/* Copyback the options, caller copys back header */
|
|
|
|
*writeback = 1;
|
|
|
|
m_copyback(m, off + sizeof(struct tcphdr),
|
|
|
|
(th->th_off << 2) - sizeof(struct tcphdr), hdr +
|
|
|
|
sizeof(struct tcphdr));
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* I have a dream.... TCP segment reassembly.... */
|
|
|
|
return (0);
|
|
|
|
}
|
|
|
|
int
|
|
|
|
pf_normalize_tcpopt(struct pf_rule *r, struct mbuf *m, struct tcphdr *th,
|
|
|
|
int off)
|
|
|
|
{
|
|
|
|
u_int16_t *mss;
|
|
|
|
int thoff;
|
|
|
|
int opt, cnt, optlen = 0;
|
|
|
|
int rewrite = 0;
|
|
|
|
u_char *optp;
|
|
|
|
|
|
|
|
thoff = th->th_off << 2;
|
|
|
|
cnt = thoff - sizeof(struct tcphdr);
|
|
|
|
optp = mtod(m, caddr_t) + off + sizeof(struct tcphdr);
|
|
|
|
|
|
|
|
for (; cnt > 0; cnt -= optlen, optp += optlen) {
|
|
|
|
opt = optp[0];
|
|
|
|
if (opt == TCPOPT_EOL)
|
|
|
|
break;
|
|
|
|
if (opt == TCPOPT_NOP)
|
|
|
|
optlen = 1;
|
|
|
|
else {
|
|
|
|
if (cnt < 2)
|
|
|
|
break;
|
|
|
|
optlen = optp[1];
|
|
|
|
if (optlen < 2 || optlen > cnt)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
switch (opt) {
|
|
|
|
case TCPOPT_MAXSEG:
|
|
|
|
mss = (u_int16_t *)(optp + 2);
|
|
|
|
if ((ntohs(*mss)) > r->max_mss) {
|
|
|
|
th->th_sum = pf_cksum_fixup(th->th_sum,
|
|
|
|
*mss, htons(r->max_mss));
|
|
|
|
*mss = htons(r->max_mss);
|
|
|
|
rewrite = 1;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return (rewrite);
|
|
|
|
}
|