/* $OpenBSD: pf.c,v 1.91 2001/07/01 17:16:03 kjell Exp $ */ /* * Copyright (c) 2001, Daniel Hartmeier * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - 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 COPYRIGHT HOLDERS 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 * COPYRIGHT HOLDERS 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "bpfilter.h" #include "pflog.h" int pf_debug = 0; #define DPFPRINTF(x) if (pf_debug) printf x /* * Tree data structure */ struct pf_tree_node { struct pf_tree_key { struct in_addr addr[2]; u_int16_t port[2]; u_int8_t proto; } key; struct pf_state *state; struct pf_tree_node *parent; struct pf_tree_node *left; struct pf_tree_node *right; signed char balance; }; struct pf_frent { LIST_ENTRY(pf_frent) fr_next; struct ip *fr_ip; struct mbuf *fr_m; }; #define PFFRAG_SEENLAST 0x0001 /* Seen the last fragment for this */ struct pf_fragment { TAILQ_ENTRY(pf_fragment) frag_next; struct in_addr fr_src; struct in_addr fr_dst; u_int8_t fr_p; /* protocol of this fragment */ u_int8_t fr_flags; /* status flags */ u_int16_t fr_id; /* fragment id for reassemble */ u_int16_t fr_max; /* fragment data max */ struct timeval fr_timeout; LIST_HEAD(pf_fragq, pf_frent) fr_queue; }; /* * Global variables */ TAILQ_HEAD(pf_fragqueue, pf_fragment) pf_fragqueue; TAILQ_HEAD(pf_rulequeue, pf_rule) pf_rules[2]; TAILQ_HEAD(pf_natqueue, pf_nat) pf_nats[2]; TAILQ_HEAD(pf_rdrqueue, pf_rdr) pf_rdrs[2]; struct pf_rulequeue *pf_rules_active; struct pf_rulequeue *pf_rules_inactive; struct pf_natqueue *pf_nats_active; struct pf_natqueue *pf_nats_inactive; struct pf_rdrqueue *pf_rdrs_active; struct pf_rdrqueue *pf_rdrs_inactive; struct pf_tree_node *tree_lan_ext, *tree_ext_gwy; struct pf_tree_node *tree_fragment; struct timeval pftv; struct pf_status pf_status; struct ifnet *status_ifp; u_int32_t pf_last_purge = 0; u_int32_t ticket_rules_active = 0; u_int32_t ticket_rules_inactive = 0; u_int32_t ticket_nats_active = 0; u_int32_t ticket_nats_inactive = 0; u_int32_t ticket_rdrs_active = 0; u_int32_t ticket_rdrs_inactive = 0; u_int16_t pf_next_port_tcp = 50001; u_int16_t pf_next_port_udp = 50001; struct pool pf_tree_pl; struct pool pf_rule_pl; struct pool pf_nat_pl; struct pool pf_rdr_pl; struct pool pf_state_pl; struct pool pf_frent_pl; struct pool pf_frag_pl; int pf_nfrents; /* * Prototypes */ int pf_tree_key_compare(struct pf_tree_key *, struct pf_tree_key *); void pf_tree_rotate_left(struct pf_tree_node **); void pf_tree_rotate_right(struct pf_tree_node **); int pf_tree_insert(struct pf_tree_node **, struct pf_tree_node *, struct pf_tree_key *, struct pf_state *); int pf_tree_remove(struct pf_tree_node **, struct pf_tree_node *, struct pf_tree_key *); struct pf_tree_node *pf_tree_first(struct pf_tree_node *); struct pf_tree_node *pf_tree_next(struct pf_tree_node *); struct pf_tree_node *pf_tree_search(struct pf_tree_node *, struct pf_tree_key *); struct pf_state *pf_find_state(struct pf_tree_node *, struct pf_tree_key *); void pf_insert_state(struct pf_state *); void pf_purge_expired_states(void); void pf_print_host(u_int32_t, u_int16_t); void pf_print_state(int, struct pf_state *); void pf_print_flags(u_int8_t); void pfattach(int); int pfopen(dev_t, int, int, struct proc *); int pfclose(dev_t, int, int, struct proc *); int pfioctl(dev_t, u_long, caddr_t, int, struct proc *); u_int16_t pf_cksum_fixup(u_int16_t, u_int16_t, u_int16_t); void pf_change_ap(u_int32_t *, u_int16_t *, u_int16_t *, u_int16_t *, u_int32_t, u_int16_t); void pf_change_a(u_int32_t *, u_int16_t *, u_int32_t); void pf_change_icmp(u_int32_t *, u_int16_t *, u_int32_t *, u_int32_t, u_int16_t, u_int16_t *, u_int16_t *, u_int16_t *, u_int16_t *); void pf_send_reset(int, struct ifnet *, struct ip *, int, struct tcphdr *); int pf_match_addr(u_int8_t, u_int32_t, u_int32_t, u_int32_t); int pf_match_port(u_int8_t, u_int16_t, u_int16_t, u_int16_t); u_int16_t pf_map_port_range(struct pf_rdr *, u_int16_t); struct pf_nat *pf_get_nat(struct ifnet *, u_int8_t, u_int32_t); struct pf_rdr *pf_get_rdr(struct ifnet *, u_int8_t, u_int32_t, u_int16_t); int pf_test_tcp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct tcphdr *); int pf_test_udp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct udphdr *); int pf_test_icmp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct icmp *); int pf_test_other(int, struct ifnet *, struct mbuf *, struct ip *); struct pf_state *pf_test_state_tcp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct tcphdr *); struct pf_state *pf_test_state_udp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct udphdr *); struct pf_state *pf_test_state_icmp(int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct icmp *); void *pf_pull_hdr(struct ifnet *, struct mbuf *, int, int, void *, int, struct ip *, u_short *, u_short *); int pflog_packet(struct mbuf *, int, u_short, u_short, struct pf_rule *); int pf_normalize_ip(struct mbuf **, int, struct ifnet *, struct ip *, u_short *); void pf_purge_expired_fragments(void); void pf_ip2key(struct pf_tree_key *, struct ip *); void pf_remove_fragment(struct pf_fragment *); void pf_flush_fragments(void); void pf_free_fragment(struct pf_fragment *); struct pf_fragment *pf_find_fragment(struct ip *); struct mbuf *pf_reassemble(struct mbuf **, struct pf_fragment *, struct pf_frent *, int); #if NPFLOG > 0 #define PFLOG_PACKET(x,a,b,c,d,e) \ do { \ HTONS((x)->ip_len); \ HTONS((x)->ip_off); \ pflog_packet(a,b,c,d,e); \ NTOHS((x)->ip_len); \ NTOHS((x)->ip_off); \ } while (0) #else #define PFLOG_PACKET #endif #define MATCH_TUPLE(h,r,d,i) \ ( \ (r->direction == d) && \ (r->ifp == NULL || r->ifp == i) && \ (!r->proto || r->proto == h->ip_p) && \ (!r->src.mask || pf_match_addr(r->src.not, r->src.addr, \ r->src.mask, h->ip_src.s_addr)) && \ (!r->dst.mask || pf_match_addr(r->dst.not, r->dst.addr, \ r->dst.mask, h->ip_dst.s_addr)) \ ) #define PFFRAG_FRENT_HIWAT 5000 /* Number of fragment entries */ #define PFFRAG_FRAG_HIWAT 1000 /* Number of fragmented packets */ int pf_tree_key_compare(struct pf_tree_key *a, struct pf_tree_key *b) { /* * could use memcmp(), but with the best manual order, we can * minimize the number of average compares. what is faster? */ if (a->proto < b->proto ) return (-1); if (a->proto > b->proto ) return ( 1); if (a->addr[0].s_addr < b->addr[0].s_addr) return (-1); if (a->addr[0].s_addr > b->addr[0].s_addr) return ( 1); if (a->addr[1].s_addr < b->addr[1].s_addr) return (-1); if (a->addr[1].s_addr > b->addr[1].s_addr) return ( 1); if (a->port[0] < b->port[0]) return (-1); if (a->port[0] > b->port[0]) return ( 1); if (a->port[1] < b->port[1]) return (-1); if (a->port[1] > b->port[1]) return ( 1); return (0); } void pf_tree_rotate_left(struct pf_tree_node **n) { struct pf_tree_node *q = *n, *p = (*n)->parent; (*n)->parent = (*n)->right; *n = (*n)->right; (*n)->parent = p; q->right = (*n)->left; if (q->right) q->right->parent = q; (*n)->left = q; q->balance--; if ((*n)->balance > 0) q->balance -= (*n)->balance; (*n)->balance--; if (q->balance < 0) (*n)->balance += q->balance; } void pf_tree_rotate_right(struct pf_tree_node **n) { struct pf_tree_node *q = *n, *p = (*n)->parent; (*n)->parent = (*n)->left; *n = (*n)->left; (*n)->parent = p; q->left = (*n)->right; if (q->left) q->left->parent = q; (*n)->right = q; q->balance++; if ((*n)->balance < 0) q->balance -= (*n)->balance; (*n)->balance++; if (q->balance > 0) (*n)->balance += q->balance; } int pf_tree_insert(struct pf_tree_node **n, struct pf_tree_node *p, struct pf_tree_key *key, struct pf_state *state) { int deltaH = 0; if (*n == NULL) { *n = pool_get(&pf_tree_pl, PR_NOWAIT); if (*n == NULL) { return (0); } bcopy(key, &(*n)->key, sizeof(struct pf_tree_key)); (*n)->state = state; (*n)->balance = 0; (*n)->parent = p; (*n)->left = (*n)->right = NULL; deltaH = 1; } else if (pf_tree_key_compare(key, &(*n)->key) > 0) { if (pf_tree_insert(&(*n)->right, *n, key, state)) { (*n)->balance++; if ((*n)->balance == 1) deltaH = 1; else if ((*n)->balance == 2) { if ((*n)->right->balance == -1) pf_tree_rotate_right(&(*n)->right); pf_tree_rotate_left(n); } } } else { if (pf_tree_insert(&(*n)->left, *n, key, state)) { (*n)->balance--; if ((*n)->balance == -1) deltaH = 1; else if ((*n)->balance == -2) { if ((*n)->left->balance == 1) pf_tree_rotate_left(&(*n)->left); pf_tree_rotate_right(n); } } } return (deltaH); } int pf_tree_remove(struct pf_tree_node **n, struct pf_tree_node *p, struct pf_tree_key *key) { int deltaH = 0; int c; if (*n == NULL) return (0); c = pf_tree_key_compare(key, &(*n)->key); if (c < 0) { if (pf_tree_remove(&(*n)->left, *n, key)) { (*n)->balance++; if ((*n)->balance == 0) deltaH = 1; else if ((*n)->balance == 2) { if ((*n)->right->balance == -1) pf_tree_rotate_right(&(*n)->right); pf_tree_rotate_left(n); if ((*n)->balance == 0) deltaH = 1; } } } else if (c > 0) { if (pf_tree_remove(&(*n)->right, *n, key)) { (*n)->balance--; if ((*n)->balance == 0) deltaH = 1; else if ((*n)->balance == -2) { if ((*n)->left->balance == 1) pf_tree_rotate_left(&(*n)->left); pf_tree_rotate_right(n); if ((*n)->balance == 0) deltaH = 1; } } } else { if ((*n)->right == NULL) { struct pf_tree_node *n0 = *n; *n = (*n)->left; if (*n != NULL) (*n)->parent = p; pool_put(&pf_tree_pl, n0); deltaH = 1; } else if ((*n)->left == NULL) { struct pf_tree_node *n0 = *n; *n = (*n)->right; if (*n != NULL) (*n)->parent = p; pool_put(&pf_tree_pl, n0); deltaH = 1; } else { struct pf_tree_node **qq = &(*n)->left; while ((*qq)->right != NULL) qq = &(*qq)->right; bcopy(&(*qq)->key, &(*n)->key, sizeof(struct pf_tree_key)); (*n)->state = (*qq)->state; bcopy(key, &(*qq)->key, sizeof(struct pf_tree_key)); if (pf_tree_remove(&(*n)->left, *n, key)) { (*n)->balance++; if ((*n)->balance == 0) deltaH = 1; else if ((*n)->balance == 2) { if ((*n)->right->balance == -1) pf_tree_rotate_right( &(*n)->right); pf_tree_rotate_left(n); if ((*n)->balance == 0) deltaH = 1; } } } } return (deltaH); } int pflog_packet(struct mbuf *m, int af, u_short dir, u_short reason, struct pf_rule *rm) { #if NBPFILTER > 0 struct ifnet *ifn, *ifp = NULL; struct pfloghdr hdr; struct mbuf m1; if (m == NULL) return(-1); hdr.af = htonl(af); /* Set the right interface name */ if (rm != NULL) ifp = rm->ifp; if (m->m_pkthdr.rcvif != NULL) ifp = m->m_pkthdr.rcvif; if (ifp != NULL) memcpy(hdr.ifname, ifp->if_xname, sizeof(hdr.ifname)); else strcpy(hdr.ifname, "unkn"); hdr.rnr = htons(rm->nr); hdr.reason = htons(reason); hdr.dir = htons(dir); hdr.action = htons(rm->action); m1.m_next = m; m1.m_len = PFLOG_HDRLEN; m1.m_data = (char *) &hdr; ifn = &(pflogif[0].sc_if); if (ifn->if_bpf) bpf_mtap(ifn->if_bpf, &m1); #endif return (0); } struct pf_tree_node * pf_tree_first(struct pf_tree_node *n) { if (n == NULL) return (NULL); /* go up to root, so the caller can pass any node. useful? */ while (n->parent) n = n->parent; while (n->left) n = n->left; return (n); } struct pf_tree_node * pf_tree_next(struct pf_tree_node *n) { if (n == NULL) return (NULL); if (n->right) { n = n->right; while (n->left) n = n->left; } else { if (n->parent && (n == n->parent->left)) n = n->parent; else { while (n->parent && (n == n->parent->right)) n = n->parent; n = n->parent; } } return (n); } struct pf_tree_node * pf_tree_search(struct pf_tree_node *n, struct pf_tree_key *key) { int c; while (n && (c = pf_tree_key_compare(&n->key, key))) n = (c > 0) ? n->left : n->right; pf_status.fcounters[FCNT_STATE_SEARCH]++; return (n); } struct pf_state * pf_find_state(struct pf_tree_node *n, struct pf_tree_key *key) { n = pf_tree_search(n, key); return (n ? n->state : NULL); } void pf_insert_state(struct pf_state *state) { struct pf_tree_key key; key.proto = state->proto; key.addr[0].s_addr = state->lan.addr; key.port[0] = state->lan.port; key.addr[1].s_addr = state->ext.addr; key.port[1] = state->ext.port; /* sanity checks can be removed later, should never occur */ if (pf_find_state(tree_lan_ext, &key) != NULL) printf("pf: ERROR! insert invalid\n"); else { pf_tree_insert(&tree_lan_ext, NULL, &key, state); if (pf_find_state(tree_lan_ext, &key) != state) printf("pf: ERROR! insert failed\n"); } key.proto = state->proto; key.addr[0].s_addr = state->ext.addr; key.port[0] = state->ext.port; key.addr[1].s_addr = state->gwy.addr; key.port[1] = state->gwy.port; if (pf_find_state(tree_ext_gwy, &key) != NULL) printf("pf: ERROR! insert invalid\n"); else { pf_tree_insert(&tree_ext_gwy, NULL, &key, state); if (pf_find_state(tree_ext_gwy, &key) != state) printf("pf: ERROR! insert failed\n"); } pf_status.fcounters[FCNT_STATE_INSERT]++; pf_status.states++; } void pf_purge_expired_states(void) { struct pf_tree_node *cur, *next; struct pf_tree_key key; cur = pf_tree_first(tree_ext_gwy); while (cur != NULL) { if (cur->state->expire <= pftv.tv_sec) { key.proto = cur->state->proto; key.addr[0].s_addr = cur->state->lan.addr; key.port[0] = cur->state->lan.port; key.addr[1].s_addr = cur->state->ext.addr; key.port[1] = cur->state->ext.port; /* remove state from second tree */ if (pf_find_state(tree_lan_ext, &key) != cur->state) printf("pf: ERROR: remove invalid!\n"); pf_tree_remove(&tree_lan_ext, NULL, &key); if (pf_find_state(tree_lan_ext, &key) != NULL) printf("pf: ERROR: remove failed\n"); /* free state */ pool_put(&pf_state_pl, cur->state); /* * remove state from tree being traversed, use next * state's key to search after removal, since removal * can invalidate pointers. */ next = pf_tree_next(cur); if (next) { key = next->key; pf_tree_remove(&tree_ext_gwy, NULL, &cur->key); cur = pf_tree_search(tree_ext_gwy, &key); if (cur == NULL) printf( "pf: ERROR: next not refound\n"); } else { pf_tree_remove(&tree_ext_gwy, NULL, &cur->key); cur = NULL; } pf_status.fcounters[FCNT_STATE_REMOVALS]++; pf_status.states--; } else cur = pf_tree_next(cur); } } void pf_print_host(u_int32_t a, u_int16_t p) { a = ntohl(a); p = ntohs(p); printf("%u.%u.%u.%u:%u", (a>>24)&255, (a>>16)&255, (a>>8)&255, a&255, p); } void pf_print_state(int direction, struct pf_state *s) { pf_print_host(s->lan.addr, s->lan.port); printf(" "); pf_print_host(s->gwy.addr, s->gwy.port); printf(" "); pf_print_host(s->ext.addr, s->ext.port); printf(" [lo=%lu high=%lu win=%u]", s->src.seqlo, s->src.seqhi, s->src.max_win); printf(" [lo=%lu high=%lu win=%u]", s->dst.seqlo, s->dst.seqhi, s->dst.max_win); printf(" %u:%u", s->src.state, s->dst.state); } void pf_print_flags(u_int8_t f) { if (f) printf(" "); if (f & TH_FIN) printf("F"); if (f & TH_SYN) printf("S"); if (f & TH_RST) printf("R"); if (f & TH_PUSH) printf("P"); if (f & TH_ACK) printf("A"); if (f & TH_URG) printf("U"); } void pfattach(int num) { /* XXX - no M_* tags, but they are not used anyway */ pool_init(&pf_tree_pl, sizeof(struct pf_tree_node), 0, 0, 0, "pftrpl", 0, NULL, NULL, 0); pool_init(&pf_rule_pl, sizeof(struct pf_rule), 0, 0, 0, "pfrulepl", 0, NULL, NULL, 0); pool_init(&pf_nat_pl, sizeof(struct pf_nat), 0, 0, 0, "pfnatpl", 0, NULL, NULL, 0); pool_init(&pf_rdr_pl, sizeof(struct pf_rdr), 0, 0, 0, "pfrdrpl", 0, NULL, NULL, 0); pool_init(&pf_state_pl, sizeof(struct pf_state), 0, 0, 0, "pfstatepl", 0, NULL, NULL, 0); pool_init(&pf_frent_pl, sizeof(struct pf_frent), 0, 0, 0, "pffrent", 0, NULL, NULL, 0); pool_init(&pf_frag_pl, sizeof(struct pf_fragment), 0, 0, 0, "pffrag", 0, NULL, NULL, 0); pool_sethiwat(&pf_frag_pl, PFFRAG_FRAG_HIWAT); pool_sethardlimit(&pf_frent_pl, PFFRAG_FRENT_HIWAT, NULL, 0); TAILQ_INIT(&pf_fragqueue); TAILQ_INIT(&pf_rules[0]); TAILQ_INIT(&pf_rules[1]); TAILQ_INIT(&pf_nats[0]); TAILQ_INIT(&pf_nats[1]); TAILQ_INIT(&pf_rdrs[0]); TAILQ_INIT(&pf_rdrs[1]); pf_rules_active = &pf_rules[0]; pf_rules_inactive = &pf_rules[1]; pf_nats_active = &pf_nats[0]; pf_nats_inactive = &pf_nats[1]; pf_rdrs_active = &pf_rdrs[0]; pf_rdrs_inactive = &pf_rdrs[1]; } int pfopen(dev_t dev, int flags, int fmt, struct proc *p) { if (minor(dev) >= 1) return (ENXIO); return (0); } int pfclose(dev_t dev, int flags, int fmt, struct proc *p) { if (minor(dev) >= 1) return (ENXIO); return (0); } int pfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p) { int error = 0; int s; if (!(flags & FWRITE)) return (EACCES); if (securelevel > 1) switch (cmd) { case DIOCSTART: case DIOCSTOP: case DIOCBEGINRULES: case DIOCADDRULE: case DIOCCOMMITRULES: case DIOCBEGINNATS: case DIOCADDNAT: case DIOCCOMMITNATS: case DIOCBEGINRDRS: case DIOCADDRDR: case DIOCCOMMITRDRS: case DIOCCLRSTATES: return EPERM; } switch (cmd) { case DIOCSTART: if (pf_status.running) error = EEXIST; else { u_int32_t states = pf_status.states; bzero(&pf_status, sizeof(struct pf_status)); pf_status.running = 1; pf_status.states = states; microtime(&pftv); pf_status.since = pftv.tv_sec; printf("pf: started\n"); } break; case DIOCSTOP: if (!pf_status.running) error = ENOENT; else { pf_status.running = 0; printf("pf: stopped\n"); } break; case DIOCBEGINRULES: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_rule *rule; while ((rule = TAILQ_FIRST(pf_rules_inactive)) != NULL) { TAILQ_REMOVE(pf_rules_inactive, rule, entries); pool_put(&pf_rule_pl, rule); } *ticket = ++ticket_rules_inactive; break; } case DIOCADDRULE: { struct pfioc_rule *pr = (struct pfioc_rule *)addr; struct pf_rule *rule, *tail; if (pr->ticket != ticket_rules_inactive) { error = EBUSY; break; } rule = pool_get(&pf_rule_pl, PR_NOWAIT); if (rule == NULL) { error = ENOMEM; break; } bcopy(&pr->rule, rule, sizeof(struct pf_rule)); tail = TAILQ_LAST(pf_rules_inactive, pf_rulequeue); rule->nr = tail ? tail->nr + 1 : 0; rule->ifp = NULL; if (rule->ifname[0]) { rule->ifp = ifunit(rule->ifname); if (rule->ifp == NULL) { pool_put(&pf_rule_pl, rule); error = EINVAL; break; } } TAILQ_INSERT_TAIL(pf_rules_inactive, rule, entries); break; } case DIOCCOMMITRULES: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_rulequeue *old_rules; struct pf_rule *rule; struct pf_tree_node *n; if (*ticket != ticket_rules_inactive) { error = EBUSY; break; } /* Swap rules, keep the old. */ s = splsoftnet(); /* * Rules are about to get freed, clear rule pointers in states */ for (n = pf_tree_first(tree_ext_gwy); n != NULL; n = pf_tree_next(n)) n->state->rule = NULL; old_rules = pf_rules_active; pf_rules_active = pf_rules_inactive; pf_rules_inactive = old_rules; ticket_rules_active = ticket_rules_inactive; splx(s); /* Purge the old rule list. */ while ((rule = TAILQ_FIRST(old_rules)) != NULL) { TAILQ_REMOVE(old_rules, rule, entries); pool_put(&pf_rule_pl, rule); } break; } case DIOCGETRULES: { struct pfioc_rule *pr = (struct pfioc_rule *)addr; struct pf_rule *tail; s = splsoftnet(); tail = TAILQ_LAST(pf_rules_active, pf_rulequeue); pr->nr = tail ? tail->nr + 1 : 0; pr->ticket = ticket_rules_active; splx(s); break; } case DIOCGETRULE: { struct pfioc_rule *pr = (struct pfioc_rule *)addr; struct pf_rule *rule; if (pr->ticket != ticket_rules_active) { error = EBUSY; break; } s = splsoftnet(); rule = TAILQ_FIRST(pf_rules_active); while ((rule != NULL) && (rule->nr != pr->nr)) rule = TAILQ_NEXT(rule, entries); if (rule == NULL) { error = EBUSY; splx(s); break; } bcopy(rule, &pr->rule, sizeof(struct pf_rule)); splx(s); break; } case DIOCBEGINNATS: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_nat *nat; while ((nat = TAILQ_FIRST(pf_nats_inactive)) != NULL) { TAILQ_REMOVE(pf_nats_inactive, nat, entries); pool_put(&pf_nat_pl, nat); } *ticket = ++ticket_nats_inactive; break; } case DIOCADDNAT: { struct pfioc_nat *pn = (struct pfioc_nat *)addr; struct pf_nat *nat; if (pn->ticket != ticket_nats_inactive) { error = EBUSY; break; } nat = pool_get(&pf_nat_pl, PR_NOWAIT); if (nat == NULL) { error = ENOMEM; break; } bcopy(&pn->nat, nat, sizeof(struct pf_nat)); nat->ifp = ifunit(nat->ifname); if (nat->ifp == NULL) { pool_put(&pf_nat_pl, nat); error = EINVAL; break; } TAILQ_INSERT_TAIL(pf_nats_inactive, nat, entries); break; } case DIOCCOMMITNATS: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_natqueue *old_nats; struct pf_nat *nat; if (*ticket != ticket_nats_inactive) { error = EBUSY; break; } /* Swap nats, keep the old. */ s = splsoftnet(); old_nats = pf_nats_active; pf_nats_active = pf_nats_inactive; pf_nats_inactive = old_nats; ticket_nats_active = ticket_nats_inactive; splx(s); /* Purge the old nat list */ while ((nat = TAILQ_FIRST(old_nats)) != NULL) { TAILQ_REMOVE(old_nats, nat, entries); pool_put(&pf_nat_pl, nat); } break; } case DIOCGETNATS: { struct pfioc_nat *pn = (struct pfioc_nat *)addr; struct pf_nat *nat; pn->nr = 0; s = splsoftnet(); TAILQ_FOREACH(nat, pf_nats_active, entries) pn->nr++; pn->ticket = ticket_nats_active; splx(s); break; } case DIOCGETNAT: { struct pfioc_nat *pn = (struct pfioc_nat *)addr; struct pf_nat *nat; u_int32_t nr; if (pn->ticket != ticket_nats_active) { error = EBUSY; break; } nr = 0; s = splsoftnet(); nat = TAILQ_FIRST(pf_nats_active); while ((nat != NULL) && (nr < pn->nr)) { nat = TAILQ_NEXT(nat, entries); nr++; } if (nat == NULL) { error = EBUSY; splx(s); break; } bcopy(nat, &pn->nat, sizeof(struct pf_nat)); splx(s); break; } case DIOCBEGINRDRS: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_rdr *rdr; while ((rdr = TAILQ_FIRST(pf_rdrs_inactive)) != NULL) { TAILQ_REMOVE(pf_rdrs_inactive, rdr, entries); pool_put(&pf_rdr_pl, rdr); } *ticket = ++ticket_rdrs_inactive; break; } case DIOCADDRDR: { struct pfioc_rdr *pr = (struct pfioc_rdr *)addr; struct pf_rdr *rdr; if (pr->ticket != ticket_rdrs_inactive) { error = EBUSY; break; } rdr = pool_get(&pf_rdr_pl, PR_NOWAIT); if (rdr == NULL) { error = ENOMEM; break; } bcopy(&pr->rdr, rdr, sizeof(struct pf_rdr)); rdr->ifp = ifunit(rdr->ifname); if (rdr->ifp == NULL) { pool_put(&pf_rdr_pl, rdr); error = EINVAL; break; } TAILQ_INSERT_TAIL(pf_rdrs_inactive, rdr, entries); break; } case DIOCCOMMITRDRS: { u_int32_t *ticket = (u_int32_t *)addr; struct pf_rdrqueue *old_rdrs; struct pf_rdr *rdr; if (*ticket != ticket_rdrs_inactive) { error = EBUSY; break; } /* Swap rdrs, keep the old. */ s = splsoftnet(); old_rdrs = pf_rdrs_active; pf_rdrs_active = pf_rdrs_inactive; pf_rdrs_inactive = old_rdrs; ticket_rdrs_active = ticket_rdrs_inactive; splx(s); /* Purge the old rdr list */ while ((rdr = TAILQ_FIRST(old_rdrs)) != NULL) { TAILQ_REMOVE(old_rdrs, rdr, entries); pool_put(&pf_rdr_pl, rdr); } break; } case DIOCGETRDRS: { struct pfioc_rdr *pr = (struct pfioc_rdr *)addr; struct pf_rdr *rdr; pr->nr = 0; s = splsoftnet(); TAILQ_FOREACH(rdr, pf_rdrs_active, entries) pr->nr++; pr->ticket = ticket_rdrs_active; splx(s); break; } case DIOCGETRDR: { struct pfioc_rdr *pr = (struct pfioc_rdr *)addr; struct pf_rdr *rdr; u_int32_t nr; if (pr->ticket != ticket_rdrs_active) { error = EBUSY; break; } nr = 0; s = splsoftnet(); rdr = TAILQ_FIRST(pf_rdrs_active); while ((rdr != NULL) && (nr < pr->nr)) { rdr = TAILQ_NEXT(rdr, entries); nr++; } if (rdr == NULL) { error = EBUSY; splx(s); break; } bcopy(rdr, &pr->rdr, sizeof(struct pf_rdr)); splx(s); break; } case DIOCCLRSTATES: { struct pf_tree_node *n; s = splsoftnet(); for (n = pf_tree_first(tree_ext_gwy); n != NULL; n = pf_tree_next(n)) n->state->expire = 0; pf_purge_expired_states(); splx(s); break; } case DIOCGETSTATE: { struct pfioc_state *ps = (struct pfioc_state *)addr; struct pf_tree_node *n; u_int32_t nr; nr = 0; s = splsoftnet(); n = pf_tree_first(tree_ext_gwy); while ((n != NULL) && (nr < ps->nr)) { n = pf_tree_next(n); nr++; } if (n == NULL) { error = EBUSY; splx(s); break; } bcopy(n->state, &ps->state, sizeof(struct pf_state)); splx(s); microtime(&pftv); ps->state.creation = pftv.tv_sec - ps->state.creation; if (ps->state.expire <= pftv.tv_sec) ps->state.expire = 0; else ps->state.expire -= pftv.tv_sec; break; } case DIOCSETSTATUSIF: { struct pfioc_if *pi = (struct pfioc_if *)addr; struct ifnet *ifp; if ((ifp = ifunit(pi->ifname)) == NULL) error = EINVAL; else status_ifp = ifp; break; } case DIOCGETSTATUS: { struct pf_status *s = (struct pf_status *)addr; bcopy(&pf_status, s, sizeof(struct pf_status)); break; } case DIOCCLRSTATUS: { u_int8_t running = pf_status.running; u_int32_t states = pf_status.states; bzero(&pf_status, sizeof(struct pf_status)); pf_status.running = running; pf_status.states = states; break; } default: error = ENODEV; break; } return (error); } u_int16_t pf_cksum_fixup(u_int16_t cksum, u_int16_t old, u_int16_t new) { u_int32_t l = cksum + old - new; l = (l >> 16) + (l & 65535); l = l & 65535; return (l ? l : 65535); } void pf_change_ap(u_int32_t *a, u_int16_t *p, u_int16_t *ic, u_int16_t *pc, u_int32_t an, u_int16_t pn) { u_int32_t ao = *a; u_int16_t po = *p; *a = an; *ic = pf_cksum_fixup(pf_cksum_fixup(*ic, ao / 65536, an / 65536), ao % 65536, an % 65536); *p = pn; *pc = pf_cksum_fixup(pf_cksum_fixup(pf_cksum_fixup(*pc, ao / 65536, an / 65536), ao % 65536, an % 65536), po, pn); } void pf_change_a(u_int32_t *a, u_int16_t *c, u_int32_t an) { u_int32_t ao = *a; *a = an; *c = pf_cksum_fixup(pf_cksum_fixup(*c, ao / 65536, an / 65536), ao % 65536, an % 65536); } void pf_change_icmp(u_int32_t *ia, u_int16_t *ip, u_int32_t *oa, u_int32_t na, u_int16_t np, u_int16_t *pc, u_int16_t *h2c, u_int16_t *ic, u_int16_t *hc) { u_int32_t oia = *ia, ooa = *oa, opc, oh2c = *h2c; u_int16_t oip = *ip; if (pc != NULL) opc = *pc; /* Change inner protocol port, fix inner protocol checksum. */ *ip = np; if (pc != NULL) *pc = pf_cksum_fixup(*pc, oip, *ip); *ic = pf_cksum_fixup(*ic, oip, *ip); if (pc != NULL) *ic = pf_cksum_fixup(*ic, opc, *pc); /* Change inner ip address, fix inner ip checksum and icmp checksum. */ *ia = na; *h2c = pf_cksum_fixup(pf_cksum_fixup(*h2c, oia / 65536, *ia / 65536), oia % 65536, *ia % 65536); *ic = pf_cksum_fixup(pf_cksum_fixup(*ic, oia / 65536, *ia / 65536), oia % 65536, *ia % 65536); *ic = pf_cksum_fixup(*ic, oh2c, *h2c); /* Change outer ip address, fix outer ip checksum. */ *oa = na; *hc = pf_cksum_fixup(pf_cksum_fixup(*hc, ooa / 65536, *oa / 65536), ooa % 65536, *oa % 65536); } void pf_send_reset(int direction, struct ifnet *ifp, struct ip *h, int off, struct tcphdr *th) { struct mbuf *m; int len = sizeof(struct ip) + sizeof(struct tcphdr); struct ip *h2; struct tcphdr *th2; /* don't reply to RST packets */ if (th->th_flags & TH_RST) return; /* create outgoing mbuf */ m = m_gethdr(M_DONTWAIT, MT_HEADER); if (m == NULL) return; m->m_data += max_linkhdr; m->m_pkthdr.len = m->m_len = len; m->m_pkthdr.rcvif = NULL; bzero(m->m_data, len); h2 = mtod(m, struct ip *); /* IP header fields included in the TCP checksum */ h2->ip_p = IPPROTO_TCP; h2->ip_len = htons(sizeof(struct tcphdr)); h2->ip_src.s_addr = h->ip_dst.s_addr; h2->ip_dst.s_addr = h->ip_src.s_addr; /* TCP header */ th2 = (struct tcphdr *)((caddr_t)h2 + sizeof(struct ip)); th2->th_sport = th->th_dport; th2->th_dport = th->th_sport; if (th->th_flags & TH_ACK) { th2->th_seq = th->th_ack; th2->th_flags = TH_RST; } else { int tlen = h->ip_len - off - (th->th_off << 2) + ((th->th_flags & TH_SYN) ? 1 : 0) + ((th->th_flags & TH_FIN) ? 1 : 0); th2->th_ack = htonl(ntohl(th->th_seq) + tlen); th2->th_flags = TH_RST | TH_ACK; } th2->th_off = sizeof(*th2) >> 2; /* TCP checksum */ th2->th_sum = in_cksum(m, len); /* Finish the IP header */ h2->ip_v = 4; h2->ip_hl = sizeof(struct ip) >> 2; h2->ip_len = htons(len); h2->ip_ttl = 128; h2->ip_sum = 0; /* IP header checksum */ h2->ip_sum = in_cksum(m, sizeof(struct ip)); if (direction == PF_IN) { /* set up route and send RST out through the same interface */ struct route iproute; struct route *ro = &iproute; struct sockaddr_in *dst; int error; bzero(ro, sizeof(*ro)); dst = (struct sockaddr_in *)&ro->ro_dst; dst->sin_family = AF_INET; dst->sin_addr = h2->ip_dst; dst->sin_len = sizeof(*dst); rtalloc(ro); if (ro->ro_rt != NULL) ro->ro_rt->rt_use++; error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst, ro->ro_rt); } else { /* send RST through the loopback interface */ struct sockaddr_in dst; dst.sin_family = AF_INET; dst.sin_addr = h2->ip_dst; dst.sin_len = sizeof(struct sockaddr_in); m->m_pkthdr.rcvif = ifp; looutput(lo0ifp, m, sintosa(&dst), NULL); } } int pf_match_addr(u_int8_t n, u_int32_t a, u_int32_t m, u_int32_t b) { return (n == !((a & m) == (b & m))); } int pf_match_port(u_int8_t op, u_int16_t a1, u_int16_t a2, u_int16_t p) { switch (op) { case PF_OP_GL: return (p >= a1) && (p <= a2); case PF_OP_EQ: return (p == a1); case PF_OP_NE: return (p != a1); case PF_OP_LT: return (p < a1); case PF_OP_LE: return (p <= a1); case PF_OP_GT: return (p > a1); case PF_OP_GE: return (p >= a1); } return (0); /* never reached */ } struct pf_nat * pf_get_nat(struct ifnet *ifp, u_int8_t proto, u_int32_t addr) { struct pf_nat *n, *nm = NULL; n = TAILQ_FIRST(pf_nats_active); while (n && nm == NULL) { if (n->ifp == ifp && (!n->proto || n->proto == proto) && pf_match_addr(n->not, n->saddr, n->smask, addr)) nm = n; else n = TAILQ_NEXT(n, entries); } return (nm); } struct pf_rdr * pf_get_rdr(struct ifnet *ifp, u_int8_t proto, u_int32_t addr, u_int16_t port) { struct pf_rdr *r, *rm = NULL; r = TAILQ_FIRST(pf_rdrs_active); while (r && rm == NULL) { if (r->ifp == ifp && (!r->proto || r->proto == proto) && pf_match_addr(r->not, r->daddr, r->dmask, addr) && (ntohs(port) >= ntohs(r->dport)) && (ntohs(port) <= ntohs(r->dport2))) rm = r; else r = TAILQ_NEXT(r, entries); } return (rm); } #define ACTION_SET(a, x) \ do { \ if ((a) != NULL) \ *(a) = (x); \ } while (0) #define REASON_SET(a, x) \ do { \ if ((a) != NULL) \ *(a) = (x); \ if (x < PFRES_MAX) \ pf_status.counters[x]++; \ } while (0) u_int16_t pf_map_port_range(struct pf_rdr *rdr, u_int16_t port) { u_int32_t nport; nport = ntohs(rdr->rport) - ntohs(rdr->dport) + ntohs(port); /* wrap around if necessary */ if (nport > 65535) nport -= 65535; return htons((u_int16_t)nport); } int pf_test_tcp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct tcphdr *th) { struct pf_nat *nat = NULL; struct pf_rdr *rdr = NULL; u_int32_t baddr; u_int16_t bport, nport; struct pf_rule *r, *rm = NULL; u_short reason; int rewrite = 0; if (direction == PF_OUT) { /* check outgoing packet for NAT */ if ((nat = pf_get_nat(ifp, IPPROTO_TCP, h->ip_src.s_addr)) != NULL) { baddr = h->ip_src.s_addr; bport = th->th_sport; pf_change_ap(&h->ip_src.s_addr, &th->th_sport, &h->ip_sum, &th->th_sum, nat->daddr, htons(pf_next_port_tcp)); rewrite++; } } else { /* check incoming packet for RDR */ if ((rdr = pf_get_rdr(ifp, IPPROTO_TCP, h->ip_dst.s_addr, th->th_dport)) != NULL) { baddr = h->ip_dst.s_addr; bport = th->th_dport; if (rdr->opts & PF_RPORT_RANGE) nport = pf_map_port_range(rdr, th->th_dport); else nport = rdr->rport; pf_change_ap(&h->ip_dst.s_addr, &th->th_dport, &h->ip_sum, &th->th_sum, rdr->raddr, nport); rewrite++; } } TAILQ_FOREACH(r, pf_rules_active, entries) { if (r->action == PF_SCRUB) continue; if (MATCH_TUPLE(h, r, direction, ifp) && ((th->th_flags & r->flagset) == r->flags) && (!r->dst.port_op || pf_match_port(r->dst.port_op, r->dst.port[0], r->dst.port[1], th->th_dport)) && (!r->src.port_op || pf_match_port(r->src.port_op, r->src.port[0], r->src.port[1], th->th_sport)) ) { rm = r; if (r->quick) break; } } if (rm != NULL) { REASON_SET(&reason, PFRES_MATCH); /* XXX will log packet before rewrite */ if (rm->log) PFLOG_PACKET(h, m, AF_INET, direction, reason, rm); if (rm->action == PF_DROP_RST) { /* undo NAT/RST changes, if they have taken place */ if (nat != NULL) { pf_change_ap(&h->ip_src.s_addr, &th->th_sport, &h->ip_sum, &th->th_sum, baddr, bport); rewrite++; } else if (rdr != NULL) { pf_change_ap(&h->ip_dst.s_addr, &th->th_dport, &h->ip_sum, &th->th_sum, baddr, bport); rewrite++; } pf_send_reset(direction, ifp, h, off, th); return (PF_DROP); } if (rm->action == PF_DROP) return (PF_DROP); } if (((rm != NULL) && rm->keep_state) || (nat != NULL) || (rdr != NULL)) { /* create new state */ u_int16_t len; struct pf_state *s; len = h->ip_len - off - (th->th_off << 2); s = pool_get(&pf_state_pl, PR_NOWAIT); if (s == NULL) { return (PF_DROP); } s->rule = rm; s->log = rm && (rm->log & 2); s->proto = IPPROTO_TCP; s->direction = direction; if (direction == PF_OUT) { s->gwy.addr = h->ip_src.s_addr; s->gwy.port = th->th_sport; s->ext.addr = h->ip_dst.s_addr; s->ext.port = th->th_dport; if (nat != NULL) { s->lan.addr = baddr; s->lan.port = bport; pf_next_port_tcp++; if (pf_next_port_tcp == 65535) pf_next_port_tcp = 50001; } else { s->lan.addr = s->gwy.addr; s->lan.port = s->gwy.port; } } else { s->lan.addr = h->ip_dst.s_addr; s->lan.port = th->th_dport; s->ext.addr = h->ip_src.s_addr; s->ext.port = th->th_sport; if (rdr != NULL) { s->gwy.addr = baddr; s->gwy.port = bport; } else { s->gwy.addr = s->lan.addr; s->gwy.port = s->lan.port; } } s->src.seqlo = ntohl(th->th_seq) + len + ((th->th_flags & TH_SYN) ? 1 : 0) + ((th->th_flags & TH_FIN) ? 1 : 0); s->src.seqhi = s->src.seqlo + 1; s->src.max_win = MAX(ntohs(th->th_win), 1); s->dst.seqlo = 0; /* Haven't seen these yet */ s->dst.seqhi = 1; s->dst.max_win = 1; s->src.state = 1; s->dst.state = 0; s->creation = pftv.tv_sec; s->expire = pftv.tv_sec + 60; s->packets = 1; s->bytes = len; pf_insert_state(s); } /* copy back packet headers if we performed NAT operations */ if (rewrite) m_copyback(m, off, sizeof(*th), (caddr_t)th); return (PF_PASS); } int pf_test_udp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct udphdr *uh) { struct pf_nat *nat = NULL; struct pf_rdr *rdr = NULL; u_int32_t baddr; u_int16_t bport, nport; struct pf_rule *r, *rm = NULL; u_short reason; int rewrite = 0; if (direction == PF_OUT) { /* check outgoing packet for NAT */ if ((nat = pf_get_nat(ifp, IPPROTO_UDP, h->ip_src.s_addr)) != NULL) { baddr = h->ip_src.s_addr; bport = uh->uh_sport; pf_change_ap(&h->ip_src.s_addr, &uh->uh_sport, &h->ip_sum, &uh->uh_sum, nat->daddr, htons(pf_next_port_udp)); rewrite++; } } else { /* check incoming packet for RDR */ if ((rdr = pf_get_rdr(ifp, IPPROTO_UDP, h->ip_dst.s_addr, uh->uh_dport)) != NULL) { baddr = h->ip_dst.s_addr; bport = uh->uh_dport; if (rdr->opts & PF_RPORT_RANGE) nport = pf_map_port_range(rdr, uh->uh_dport); else nport = rdr->rport; pf_change_ap(&h->ip_dst.s_addr, &uh->uh_dport, &h->ip_sum, &uh->uh_sum, rdr->raddr, nport); rewrite++; } } TAILQ_FOREACH(r, pf_rules_active, entries) { if (r->action == PF_SCRUB) continue; if (MATCH_TUPLE(h, r, direction, ifp) && (!r->dst.port_op || pf_match_port(r->dst.port_op, r->dst.port[0], r->dst.port[1], uh->uh_dport)) && (!r->src.port_op || pf_match_port(r->src.port_op, r->src.port[0], r->src.port[1], uh->uh_sport))) { rm = r; if (r->quick) break; } } if (rm != NULL) { REASON_SET(&reason, PFRES_MATCH); /* XXX will log packet before rewrite */ if (rm->log) PFLOG_PACKET(h, m, AF_INET, direction, reason, rm); if (rm->action != PF_PASS) return (PF_DROP); } if ((rm != NULL && rm->keep_state) || nat != NULL || rdr != NULL) { /* create new state */ u_int16_t len; struct pf_state *s; len = h->ip_len - off - 8; s = pool_get(&pf_state_pl, PR_NOWAIT); if (s == NULL) { return (PF_DROP); } s->rule = rm; s->log = rm && (rm->log & 2); s->proto = IPPROTO_UDP; s->direction = direction; if (direction == PF_OUT) { s->gwy.addr = h->ip_src.s_addr; s->gwy.port = uh->uh_sport; s->ext.addr = h->ip_dst.s_addr; s->ext.port = uh->uh_dport; if (nat != NULL) { s->lan.addr = baddr; s->lan.port = bport; pf_next_port_udp++; if (pf_next_port_udp == 65535) pf_next_port_udp = 50001; } else { s->lan.addr = s->gwy.addr; s->lan.port = s->gwy.port; } } else { s->lan.addr = h->ip_dst.s_addr; s->lan.port = uh->uh_dport; s->ext.addr = h->ip_src.s_addr; s->ext.port = uh->uh_sport; if (rdr != NULL) { s->gwy.addr = baddr; s->gwy.port = bport; } else { s->gwy.addr = s->lan.addr; s->gwy.port = s->lan.port; } } s->src.seqlo = 0; s->src.seqhi = 0; s->src.max_win = 0; s->src.state = 1; s->dst.seqlo = 0; s->dst.seqhi = 0; s->dst.max_win = 0; s->dst.state = 0; s->creation = pftv.tv_sec; s->expire = pftv.tv_sec + 30; s->packets = 1; s->bytes = len; pf_insert_state(s); } /* copy back packet headers if we performed NAT operations */ if (rewrite) m_copyback(m, off, sizeof(*uh), (caddr_t)uh); return (PF_PASS); } int pf_test_icmp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct icmp *ih) { struct pf_nat *nat = NULL; u_int32_t baddr; struct pf_rule *r, *rm = NULL; u_short reason; int rewrite = 0; if (direction == PF_OUT) { /* check outgoing packet for NAT */ if ((nat = pf_get_nat(ifp, IPPROTO_ICMP, h->ip_src.s_addr)) != NULL) { baddr = h->ip_src.s_addr; pf_change_a(&h->ip_src.s_addr, &h->ip_sum, nat->daddr); rewrite++; } } TAILQ_FOREACH(r, pf_rules_active, entries) { if (r->action == PF_SCRUB) continue; if (MATCH_TUPLE(h, r, direction, ifp) && (!r->type || (r->type == ih->icmp_type + 1)) && (!r->code || (r->code == ih->icmp_code + 1)) ) { rm = r; if (r->quick) break; } } if (rm != NULL) { REASON_SET(&reason, PFRES_MATCH); /* XXX will log packet before rewrite */ if (rm->log) PFLOG_PACKET(h, m, AF_INET, direction, reason, rm); if (rm->action != PF_PASS) return (PF_DROP); } if ((rm != NULL && rm->keep_state) || nat != NULL) { /* create new state */ u_int16_t len; u_int16_t id; struct pf_state *s; len = h->ip_len - off - 8; id = ih->icmp_id; s = pool_get(&pf_state_pl, PR_NOWAIT); if (s == NULL) { return (PF_DROP); } s->rule = rm; s->log = rm && (rm->log & 2); s->proto = IPPROTO_ICMP; s->direction = direction; if (direction == PF_OUT) { s->gwy.addr = h->ip_src.s_addr; s->gwy.port = id; s->ext.addr = h->ip_dst.s_addr; s->ext.port = id; s->lan.addr = nat ? baddr : s->gwy.addr; s->lan.port = id; } else { s->lan.addr = h->ip_dst.s_addr; s->lan.port = id; s->ext.addr = h->ip_src.s_addr; s->ext.port = id; s->gwy.addr = s->lan.addr; s->gwy.port = id; } s->src.seqlo = 0; s->src.seqhi = 0; s->src.max_win = 0; s->src.state = 0; s->dst.seqlo = 0; s->dst.seqhi = 0; s->dst.max_win = 0; s->dst.state = 0; s->creation = pftv.tv_sec; s->expire = pftv.tv_sec + 20; s->packets = 1; s->bytes = len; pf_insert_state(s); } /* copy back packet headers if we performed NAT operations */ if (rewrite) m_copyback(m, off, sizeof(*ih), (caddr_t)ih); return (PF_PASS); } int pf_test_other(int direction, struct ifnet *ifp, struct mbuf *m, struct ip *h) { struct pf_rule *r, *rm = NULL; TAILQ_FOREACH(r, pf_rules_active, entries) { if (r->action == PF_SCRUB) continue; if (MATCH_TUPLE(h, r, direction, ifp)) { rm = r; if (r->quick) break; } } if (rm != NULL) { u_short reason; REASON_SET(&reason, PFRES_MATCH); if (rm->log) PFLOG_PACKET(h, m, AF_INET, direction, reason, rm); if (rm->action != PF_PASS) return (PF_DROP); } return (PF_PASS); } struct pf_state * pf_test_state_tcp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct tcphdr *th) { struct pf_state *s; struct pf_tree_key key; int rewrite = 0; key.proto = IPPROTO_TCP; key.addr[0] = h->ip_src; key.port[0] = th->th_sport; key.addr[1] = h->ip_dst; key.port[1] = th->th_dport; s = pf_find_state((direction == PF_IN) ? tree_ext_gwy : tree_lan_ext, &key); if (s != NULL) { u_int16_t len = h->ip_len - off - (th->th_off << 2); u_int16_t win = ntohs(th->th_win); u_int32_t seq = ntohl(th->th_seq), ack = ntohl(th->th_ack); u_int32_t end = seq + len + ((th->th_flags & TH_SYN) ? 1 : 0) + ((th->th_flags & TH_FIN) ? 1 : 0); int ackskew; struct pf_state_peer *src, *dst; if (direction == s->direction) { src = &s->src; dst = &s->dst; } else { src = &s->dst; dst = &s->src; } if (src->seqlo == 0) { /* First packet from this end. Set its state */ src->seqlo = end; src->seqhi = end + 1; src->max_win = 1; } if ((th->th_flags & TH_ACK) == 0) { /* Let it pass through the ack skew check */ ack = dst->seqlo; } else if (ack == 0 && (th->th_flags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) { /* broken tcp stacks do not set ack */ ack = dst->seqlo; } if (seq == end) { /* Ease sequencing restrictions on no data packets */ seq = src->seqlo; end = seq; } ackskew = dst->seqlo - ack; #define MAXACKWINDOW (0xffff + 1500) if (SEQ_GEQ(src->seqhi, end) && /* Last octet inside other's window space */ SEQ_GEQ(seq, src->seqlo - dst->max_win) && /* Retrans: not more than one window back */ (ackskew >= -MAXACKWINDOW) && /* Acking not more than one window back */ (ackskew <= MAXACKWINDOW)) { /* Acking not more than one window forward */ if (ackskew < 0) { /* The sequencing algorithm is exteremely lossy * when there is fragmentation since the full * packet length can not be determined. So we * deduce how much data passed by what the * other endpoint ACKs. Thanks Guido! * (Why MAXACKWINDOW is used) */ dst->seqlo = ack; } s->packets++; s->bytes += len; /* update max window */ if (src->max_win < win) src->max_win = win; /* syncronize sequencing */ if (SEQ_GT(end, src->seqlo)) src->seqlo = end; /* slide the window of what the other end can send */ if (SEQ_GEQ(ack + win, dst->seqhi)) dst->seqhi = ack + MAX(win, 1); /* update states */ if (th->th_flags & TH_SYN) if (src->state < 1) src->state = 1; if (th->th_flags & TH_FIN) if (src->state < 3) src->state = 3; if (th->th_flags & TH_ACK) { if (dst->state == 1) dst->state = 2; else if (dst->state == 3) dst->state = 4; } if (th->th_flags & TH_RST) src->state = dst->state = 5; /* update expire time */ if (src->state >= 4 && dst->state >= 4) s->expire = pftv.tv_sec + 5; else if (src->state >= 3 || dst->state >= 3) s->expire = pftv.tv_sec + 300; else if (src->state < 2 || dst->state < 2) s->expire = pftv.tv_sec + 30; else s->expire = pftv.tv_sec + 24*60*60; /* translate source/destination address, if needed */ if (s->lan.addr != s->gwy.addr || s->lan.port != s->gwy.port) { if (direction == PF_OUT) pf_change_ap(&h->ip_src.s_addr, &th->th_sport, &h->ip_sum, &th->th_sum, s->gwy.addr, s->gwy.port); else pf_change_ap(&h->ip_dst.s_addr, &th->th_dport, &h->ip_sum, &th->th_sum, s->lan.addr, s->lan.port); rewrite++; } } else { /* XXX Remove these printfs before release */ printf("pf: BAD state: "); pf_print_state(direction, s); pf_print_flags(th->th_flags); printf(" seq=%lu ack=%lu len=%u ", seq, ack, len); printf("\n"); printf("State failure: %c %c %c %c\n", SEQ_GEQ(src->seqhi, end) ? ' ' : '1', SEQ_GEQ(seq, src->seqlo - dst->max_win) ? ' ': '2', (ackskew >= -MAXACKWINDOW) ? ' ' : '3', (ackskew <= MAXACKWINDOW) ? ' ' : '4'); s = NULL; } /* copy back packet headers if we performed NAT operations */ if (rewrite) m_copyback(m, off, sizeof(*th), (caddr_t)th); return (s); } return (NULL); } struct pf_state * pf_test_state_udp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct udphdr *uh) { struct pf_state *s; struct pf_tree_key key; int rewrite = 0; key.proto = IPPROTO_UDP; key.addr[0] = h->ip_src; key.port[0] = uh->uh_sport; key.addr[1] = h->ip_dst; key.port[1] = uh->uh_dport; s = pf_find_state((direction == PF_IN) ? tree_ext_gwy : tree_lan_ext, &key); if (s != NULL) { u_int16_t len = h->ip_len - off - 8; struct pf_state_peer *src, *dst; if (direction == s->direction) { src = &s->src; dst = &s->dst; } else { src = &s->dst; dst = &s->src; } s->packets++; s->bytes += len; /* update states */ if (src->state < 1) src->state = 1; if (dst->state == 1) dst->state = 2; /* update expire time */ if (src->state == 2 && dst->state == 2) s->expire = pftv.tv_sec + 60; else s->expire = pftv.tv_sec + 20; /* translate source/destination address, if necessary */ if (s->lan.addr != s->gwy.addr || s->lan.port != s->gwy.port) { if (direction == PF_OUT) pf_change_ap(&h->ip_src.s_addr, &uh->uh_sport, &h->ip_sum, &uh->uh_sum, s->gwy.addr, s->gwy.port); else pf_change_ap(&h->ip_dst.s_addr, &uh->uh_dport, &h->ip_sum, &uh->uh_sum, s->lan.addr, s->lan.port); rewrite++; } /* copy back packet headers if we performed NAT operations */ if (rewrite) m_copyback(m, off, sizeof(*uh), (caddr_t)uh); return (s); } return (NULL); } struct pf_state * pf_test_state_icmp(int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct icmp *ih) { u_int16_t len = h->ip_len - off - sizeof(*ih); int rewrite = 0; if (ih->icmp_type != ICMP_UNREACH && ih->icmp_type != ICMP_SOURCEQUENCH && ih->icmp_type != ICMP_REDIRECT && ih->icmp_type != ICMP_TIMXCEED && ih->icmp_type != ICMP_PARAMPROB) { /* * ICMP query/reply message not related to a TCP/UDP packet. * Search for an ICMP state. */ struct pf_state *s; struct pf_tree_key key; key.proto = IPPROTO_ICMP; key.addr[0] = h->ip_src; key.port[0] = ih->icmp_id; key.addr[1] = h->ip_dst; key.port[1] = ih->icmp_id; s = pf_find_state((direction == PF_IN) ? tree_ext_gwy : tree_lan_ext, &key); if (s != NULL) { s->packets++; s->bytes += len; s->expire = pftv.tv_sec + 10; /* translate source/destination address, if needed */ if (s->lan.addr != s->gwy.addr) { if (direction == PF_OUT) pf_change_a(&h->ip_src.s_addr, &h->ip_sum, s->gwy.addr); else pf_change_a(&h->ip_dst.s_addr, &h->ip_sum, s->lan.addr); } return (s); } return (NULL); } else { /* * ICMP error message in response to a TCP/UDP packet. * Extract the inner TCP/UDP header and search for that state. */ struct ip h2; int ipoff2; int off2; ipoff2 = off + 8; /* offset of h2 in mbuf chain */ if (!pf_pull_hdr(ifp, m, 0, ipoff2, &h2, sizeof(h2), h, NULL, NULL)) { printf("pf: ICMP error message too short (ip)\n"); return (NULL); } /* offset of protocol header that follows h2 */ off2 = ipoff2 + (h2.ip_hl << 2); switch (h2.ip_p) { case IPPROTO_TCP: { struct tcphdr th; u_int32_t seq, end; struct pf_state *s; struct pf_tree_key key; struct pf_state_peer *src, *dst; /* * Only the first 8 bytes of the TCP header can be * expected. Don't access any TCP header fields after * th_seq, an ackskew test is not possible. */ if (!pf_pull_hdr(ifp, m, ipoff2, off2, &th, 8, &h2, NULL, NULL)) { printf("pf: " "ICMP error message too short (tcp)\n"); return (NULL); } seq = ntohl(th.th_seq); end = seq + h2.ip_len - ((h2.ip_hl + th.th_off)<<2) + ((th.th_flags & TH_SYN) ? 1 : 0) + ((th.th_flags & TH_FIN) ? 1 : 0); key.proto = IPPROTO_TCP; key.addr[0] = h2.ip_dst; key.port[0] = th.th_dport; key.addr[1] = h2.ip_src; key.port[1] = th.th_sport; s = pf_find_state((direction == PF_IN) ? tree_ext_gwy : tree_lan_ext, &key); if (s == NULL) return (NULL); src = (direction == s->direction) ? &s->dst : &s->src; dst = (direction == s->direction) ? &s->src : &s->dst; if (!SEQ_GEQ(src->seqhi, end) || !SEQ_GEQ(seq, src->seqlo - dst->max_win)) { printf("pf: BAD ICMP state: "); pf_print_state(direction, s); printf(" seq=%lu\n", seq); return (NULL); } if (s->lan.addr != s->gwy.addr || s->lan.port != s->gwy.port) { if (direction == PF_IN) { pf_change_icmp(&h2.ip_src.s_addr, &th.th_sport, &h->ip_dst.s_addr, s->lan.addr, s->lan.port, NULL, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } else { pf_change_icmp(&h2.ip_dst.s_addr, &th.th_dport, &h->ip_src.s_addr, s->gwy.addr, s->gwy.port, NULL, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } rewrite++; } /* * copy back packet headers if we performed NAT * operations */ if (rewrite) { m_copyback(m, off, sizeof(*ih), (caddr_t)ih); m_copyback(m, ipoff2, sizeof(h2), (caddr_t)&h2); m_copyback(m, off2, 8, (caddr_t)&th); } return (s); break; } case IPPROTO_UDP: { struct udphdr uh; struct pf_state *s; struct pf_tree_key key; if (!pf_pull_hdr(ifp, m, ipoff2, off2, &uh, sizeof(uh), &h2, NULL, NULL)) { printf("pf: ICMP error message too short (udp)\n"); return (NULL); } key.proto = IPPROTO_UDP; key.addr[0] = h2.ip_dst; key.port[0] = uh.uh_dport; key.addr[1] = h2.ip_src; key.port[1] = uh.uh_sport; s = pf_find_state(direction == PF_IN ? tree_ext_gwy : tree_lan_ext, &key); if (s == NULL) return (NULL); if (s->lan.addr != s->gwy.addr || s->lan.port != s->gwy.port) { if (direction == PF_IN) { pf_change_icmp(&h2.ip_src.s_addr, &uh.uh_sport, &h->ip_dst.s_addr, s->lan.addr, s->lan.port, &uh.uh_sum, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } else { pf_change_icmp(&h2.ip_dst.s_addr, &uh.uh_dport, &h->ip_src.s_addr, s->gwy.addr, s->gwy.port, &uh.uh_sum, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } rewrite++; } /* * copy back packet headers if we performed NAT * operations */ if (rewrite) { m_copyback(m, off, sizeof(*ih), (caddr_t)ih); m_copyback(m, ipoff2, sizeof(h2), (caddr_t)&h2); m_copyback(m, off2, sizeof(uh), (caddr_t)&uh); } return (s); break; } default: printf("pf: ICMP error message for bad proto\n"); return (NULL); } return (NULL); } } #define FRAG_EXPIRE 30 void pf_purge_expired_fragments(void) { struct pf_fragment *frag; struct timeval now, expire; microtime(&now); timerclear(&expire); expire.tv_sec = FRAG_EXPIRE; timersub(&now, &expire, &expire); while ((frag = TAILQ_LAST(&pf_fragqueue, pf_fragqueue)) != NULL) { DPFPRINTF((__FUNCTION__": %d,%d > %d,%d\n", frag->fr_timeout.tv_sec, frag->fr_timeout.tv_usec, expire.tv_sec, expire.tv_usec)); if (timercmp(&frag->fr_timeout, &expire, >)) break; DPFPRINTF((__FUNCTION__": expiring %p\n", frag)); pf_free_fragment(frag); } } /* * Try to flush old fragments to make space for new ones */ void pf_flush_fragments(void) { struct pf_fragment *frag; int goal = pf_nfrents * 9 / 10; DPFPRINTF((__FUNCTION__": trying to free > %d frents\n", pf_nfrents - goal)); while (goal < pf_nfrents) { frag = TAILQ_LAST(&pf_fragqueue, pf_fragqueue); if (frag == NULL) break; pf_free_fragment(frag); } } /* Frees the fragments and all associated entries */ void pf_free_fragment(struct pf_fragment *frag) { struct pf_frent *frent; /* Free all fragments */ for (frent = LIST_FIRST(&frag->fr_queue); frent; frent = LIST_FIRST(&frag->fr_queue)) { LIST_REMOVE(frent, fr_next); m_freem(frent->fr_m); pool_put(&pf_frent_pl, frent); pf_nfrents--; } pf_remove_fragment(frag); } void pf_ip2key(struct pf_tree_key *key, struct ip *ip) { key->proto = ip->ip_p; key->addr[0] = ip->ip_src; key->addr[1] = ip->ip_dst; key->port[0] = ip->ip_id; key->port[1] = 0; } struct pf_fragment * pf_find_fragment(struct ip *ip) { struct pf_tree_key key; struct pf_fragment *frag; pf_ip2key(&key, ip); frag = (struct pf_fragment *)pf_find_state(tree_fragment, &key); if (frag != NULL) { microtime(&frag->fr_timeout); TAILQ_REMOVE(&pf_fragqueue, frag, frag_next); TAILQ_INSERT_HEAD(&pf_fragqueue, frag, frag_next); } return (frag); } /* Removes a fragment from the fragment queue and frees the fragment */ void pf_remove_fragment(struct pf_fragment *frag) { struct pf_tree_key key; key.proto = frag->fr_p; key.addr[0] = frag->fr_src; key.addr[1] = frag->fr_dst; key.port[0] = frag->fr_id; key.port[1] = 0; pf_tree_remove(&tree_fragment, NULL, &key); TAILQ_REMOVE(&pf_fragqueue, frag, frag_next); pool_put(&pf_frag_pl, frag); } struct mbuf * pf_reassemble(struct mbuf **m0, struct pf_fragment *frag, struct pf_frent *frent, int mff) { struct mbuf *m = *m0, *m2; struct pf_frent *frep, *frea, *next; struct ip *ip = frent->fr_ip; int hlen = ip->ip_hl << 2; u_int16_t off = ip->ip_off; u_int16_t max = ip->ip_len + off; /* Strip off ip header */ m->m_data += hlen; m->m_len -= hlen; /* Create a new reassembly queue for this packet */ if (frag == NULL) { struct pf_tree_key key; frag = pool_get(&pf_frag_pl, M_NOWAIT); if (frag == NULL) { pf_flush_fragments(); frag = pool_get(&pf_frag_pl, M_NOWAIT); if (frag == NULL) goto drop_fragment; } frag->fr_flags = 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; LIST_INIT(&frag->fr_queue); pf_ip2key(&key, frent->fr_ip); pf_tree_insert(&tree_fragment, NULL, &key, (struct pf_state *)frag); TAILQ_INSERT_HEAD(&pf_fragqueue, frag, frag_next); DPFPRINTF((__FUNCTION__": insert new fragment\n")); /* 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 (frea->fr_ip->ip_off > off) break; frep = frea; } KASSERT(frep != NULL || frea != NULL); if (frep != NULL) { u_int16_t precut; precut = frep->fr_ip->ip_off + frep->fr_ip->ip_len - off; if (precut > ip->ip_len) goto drop_fragment; m_adj(frent->fr_m, precut); /* We enforce 8 byte boundaries, ip_off not converted yet */ off = ip->ip_off += precut; ip->ip_len -= precut; } for (; frea != NULL && ip->ip_len + off > frea->fr_ip->ip_off; frea = next) { u_int16_t aftercut; aftercut = (ip->ip_len + off) - frea->fr_ip->ip_off; if (aftercut < frea->fr_ip->ip_len) { frea->fr_ip->ip_len -= aftercut; frea->fr_ip->ip_off += aftercut; 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 maxmimum 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 += frep->fr_ip->ip_len; if (off < frag->fr_max && (next == NULL || next->fr_ip->ip_off != off)) return (NULL); } DPFPRINTF((__FUNCTION__": %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((__FUNCTION__": drop: too big: %d\n", off)); pf_free_fragment(frag); 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) { DPFPRINTF((__FUNCTION__": frent %p\n", frent)); 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); hlen = ip->ip_hl << 2; ip->ip_len = 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((__FUNCTION__": complete: %p(%d)\n", m, ip->ip_len)); return (m); drop_fragment: /* Oops - fail safe - drop packet */ m_freem(m); return (NULL); } int pf_normalize_ip(struct mbuf **m0, int dir, struct ifnet *ifp, struct ip *h, u_short *reason) { struct mbuf *m = *m0; struct pf_rule *r; struct pf_frent *frent; struct pf_fragment *frag; int mff = (h->ip_off & IP_MF), hlen = h->ip_hl << 2; u_int16_t fragoff = (h->ip_off & IP_OFFMASK) << 3; u_int16_t max; TAILQ_FOREACH(r, pf_rules_active, entries) { if ((r->action == PF_SCRUB) && MATCH_TUPLE(h, r, dir, ifp)) break; } if (r == NULL) return (PF_PASS); /* Check for illegal packets */ if (hlen < sizeof(struct ip)) goto drop; if (hlen > h->ip_len) goto drop; /* We will need other tests here */ if (!fragoff && !mff) return (PF_PASS); /* Now we are dealing with a fragmented packet */ frag = pf_find_fragment(h); /* This can not happen */ if (h->ip_off & IP_DF) { DPFPRINTF((__FUNCTION__": IP_DF\n")); goto bad; } h->ip_len -= hlen; h->ip_off <<= 3; /* All fragments are 8 byte aligned */ if (mff && (h->ip_len & 0x7)) { DPFPRINTF((__FUNCTION__": mff and %d\n", h->ip_len)); goto bad; } max = fragoff + h->ip_len; /* Respect maximum length */ if (max > IP_MAXPACKET) { DPFPRINTF((__FUNCTION__": max packet %d\n", max)); goto bad; } /* 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) { /* Try to clean up old fragments */ pf_flush_fragments(); 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((__FUNCTION__": reass frag @ %d\n", fragoff)); *m0 = m = pf_reassemble(m0, frag, frent, mff); return (m == NULL ? PF_DROP : PF_PASS); drop: REASON_SET(reason, PFRES_NORM); if (r != NULL && r->log) PFLOG_PACKET(h, m, AF_INET, dir, *reason, r); return (PF_DROP); bad: DPFPRINTF((__FUNCTION__": dropping bad fragment\n")); /* Free assoicated fragments */ if (frag != NULL) pf_free_fragment(frag); if (r != NULL && r->log) PFLOG_PACKET(h, m, AF_INET, dir, *reason, r); return (PF_DROP); } /* * ipoff and off are measured from the start of the mbuf chain. * h must be at "ipoff" on the mbuf chain. */ void * pf_pull_hdr(struct ifnet *ifp, struct mbuf *m, int ipoff, int off, void *p, int len, struct ip *h, u_short *actionp, u_short *reasonp) { u_int16_t fragoff = (h->ip_off & IP_OFFMASK) << 3; /* sanity check */ if (ipoff > off) { ACTION_SET(actionp, PF_DROP); REASON_SET(reasonp, PFRES_BADOFF); return (NULL); } if (fragoff) { if (fragoff >= len) ACTION_SET(actionp, PF_PASS); else { ACTION_SET(actionp, PF_DROP); REASON_SET(reasonp, PFRES_FRAG); } return (NULL); } if (m->m_pkthdr.len < off + len || ipoff + h->ip_len < off + len) { ACTION_SET(actionp, PF_DROP); REASON_SET(reasonp, PFRES_SHORT); return (NULL); } m_copydata(m, off, len, p); return (p); } int pf_test(int dir, struct ifnet *ifp, struct mbuf **m0) { u_short action, reason = 0, log = 0; struct mbuf *m = *m0; struct ip *h; struct pf_rule *r = NULL; struct pf_state *s; int off; if (!pf_status.running) return (PF_PASS); #ifdef DIAGNOSTIC if ((m->m_flags & M_PKTHDR) == 0) panic("non-M_PKTHDR is passed to pf_test"); #endif /* purge expire states, at most once every 10 seconds */ microtime(&pftv); if (pftv.tv_sec - pf_last_purge >= 10) { pf_purge_expired_states(); pf_purge_expired_fragments(); pf_last_purge = pftv.tv_sec; } if (m->m_pkthdr.len < sizeof(*h)) { action = PF_DROP; REASON_SET(&reason, PFRES_SHORT); log = 1; goto done; } h = mtod(m, struct ip *); /* We do IP header normalization and packet reassembly here */ if (pf_normalize_ip(m0, dir, ifp, h, &reason) != PF_PASS) { ACTION_SET(&action, PF_DROP); goto done; } m = *m0; h = mtod(m, struct ip *); off = h->ip_hl << 2; switch (h->ip_p) { case IPPROTO_TCP: { struct tcphdr th; if (!pf_pull_hdr(ifp, m, 0, off, &th, sizeof(th), h, &action, &reason)) { log = action != PF_PASS; goto done; } if ((s = pf_test_state_tcp(dir, ifp, m, 0, off, h, &th))) { action = PF_PASS; r = s->rule; log = s->log; } else action = pf_test_tcp(dir, ifp, m, 0, off, h, &th); break; } case IPPROTO_UDP: { struct udphdr uh; if (!pf_pull_hdr(ifp, m, 0, off, &uh, sizeof(uh), h, &action, &reason)) { log = action != PF_PASS; goto done; } if ((s = pf_test_state_udp(dir, ifp, m, 0, off, h, &uh))) { action = PF_PASS; r = s->rule; log = s->log; } else action = pf_test_udp(dir, ifp, m, 0, off, h, &uh); break; } case IPPROTO_ICMP: { struct icmp ih; if (!pf_pull_hdr(ifp, m, 0, off, &ih, sizeof(ih), h, &action, &reason)) { log = action != PF_PASS; goto done; } if ((s = pf_test_state_icmp(dir, ifp, m, 0, off, h, &ih))) { action = PF_PASS; r = s->rule; log = s->log; } else action = pf_test_icmp(dir, ifp, m, 0, off, h, &ih); break; } default: action = pf_test_other(dir, ifp, m, h); break; } done: if (ifp == status_ifp) { pf_status.bcounters[dir] += h->ip_len; pf_status.pcounters[dir][action]++; } if (log) { struct pf_rule r0; if (r == NULL) { r0.ifp = ifp; r0.action = action; r0.nr = -1; r = &r0; } PFLOG_PACKET(h, m, AF_INET, dir, reason, r); } return (action); }