/* $OpenBSD: pf.c,v 1.117 2001/07/19 00:07:36 krw 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 #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 key; struct pf_state *state; struct pf_tree_node *parent; struct pf_tree_node *left; struct pf_tree_node *right; int balance; }; /* * Global variables */ TAILQ_HEAD(pf_natqueue, pf_nat) pf_nats[2]; TAILQ_HEAD(pf_rdrqueue, pf_rdr) pf_rdrs[2]; struct pf_rulequeue pf_rules[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 timeval pftv; struct pf_status pf_status; struct ifnet *status_ifp; u_int32_t pf_last_purge; u_int32_t ticket_rules_active; u_int32_t ticket_rules_inactive; u_int32_t ticket_nats_active; u_int32_t ticket_nats_inactive; u_int32_t ticket_rdrs_active; u_int32_t ticket_rdrs_inactive; u_int16_t pf_next_port_tcp = 50001; u_int16_t pf_next_port_udp = 50001; struct pool pf_tree_pl, pf_rule_pl, pf_nat_pl; struct pool pf_rdr_pl, pf_state_pl; 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 **); 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 *); 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(struct ip *, int, struct tcphdr *); void pf_send_icmp(struct mbuf *, u_int8_t, u_int8_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, u_int32_t); struct pf_rdr *pf_get_rdr(struct ifnet *, u_int8_t, u_int32_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 *); int pf_test_state_tcp(struct pf_state **, int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct tcphdr *); int pf_test_state_udp(struct pf_state **, int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct udphdr *); int pf_test_state_icmp(struct pf_state **, int, struct ifnet *, struct mbuf *, int, int, struct ip *, struct icmp *); void *pf_pull_hdr(struct mbuf *, int, void *, int, u_short *, u_short *); #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 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); 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))) if (c > 0) n = n->left; else n = 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); if (n) return (n->state); else return (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); 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]; pf_normalize_init(); } 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); if (tail) rule->nr = tail->nr + 1; else rule->nr = 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; } } else rule->ifp = NULL; 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); if (tail) pr->nr = tail->nr + 1; else pr->nr = 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)); if (nat->ifname[0]) { nat->ifp = ifunit(nat->ifname); if (nat->ifp == NULL) { pool_put(&pf_nat_pl, nat); error = EINVAL; break; } } else nat->ifp = NULL; 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)); if (rdr->ifname[0]) { rdr->ifp = ifunit(rdr->ifname); if (rdr->ifp == NULL) { pool_put(&pf_rdr_pl, rdr); error = EINVAL; break; } } else rdr->ifp = NULL; 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; } case DIOCNATLOOK: { struct pf_natlook *pnl = (struct pf_natlook *)addr; struct pf_state *st; struct pf_tree_key key; int direction = pnl->direction; key.proto = pnl->proto; /* * userland gives us source and dest of connetion, reverse * the lookup so we ask for what happens with the return * traffic, enabling us to find it in the state tree. */ key.addr[1].s_addr = pnl->saddr; key.port[1] = pnl->sport; key.addr[0].s_addr = pnl->daddr; key.port[0] = pnl->dport; if (!pnl->proto || !pnl->saddr || !pnl->daddr || !pnl->dport || !pnl->sport) error = EINVAL; else { s = splsoftnet(); if (direction == PF_IN) st = pf_find_state(tree_ext_gwy, &key); else st = pf_find_state(tree_lan_ext, &key); if (st != NULL) { if (direction == PF_IN) { pnl->rsaddr = st->lan.addr; pnl->rsport = st->lan.port; pnl->rdaddr = pnl->daddr; pnl->rdport = pnl->dport; } else { pnl->rdaddr = st->gwy.addr; pnl->rdport = st->gwy.port; pnl->rsaddr = pnl->saddr; pnl->rsport = pnl->sport; } } else error = ENOENT; splx(s); } 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; if (l) return (l); else return (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(struct ip *h, int off, struct tcphdr *th) { struct mbuf *m; struct m_tag *mtag; 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 */ mtag = m_tag_get(PACKET_TAG_PF_GENERATED, 0, M_NOWAIT); if (mtag == NULL) return; m = m_gethdr(M_DONTWAIT, MT_HEADER); if (m == NULL) { m_tag_free(mtag); return; } m_tag_prepend(m, mtag); 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(*th2)); 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); if (th->th_flags & TH_SYN) tlen++; if (th->th_flags & TH_FIN) tlen++; 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(*h2) >> 2; h2->ip_ttl = 128; h2->ip_sum = 0; h2->ip_len = len; h2->ip_off = 0; ip_output(m, NULL, NULL, 0, NULL, NULL); } void pf_send_icmp(struct mbuf *m, u_int8_t type, u_int8_t code) { struct m_tag *mtag; struct mbuf *m0; mtag = m_tag_get(PACKET_TAG_PF_GENERATED, 0, M_NOWAIT); if (mtag == NULL) return; m0 = m_copy(m, 0, M_COPYALL); if (m0 == NULL) { m_tag_free(mtag); return; } m_tag_prepend(m0, mtag); icmp_error(m0, type, code, 0, 0); } /* * Return 1 if the addresses a and b match (with mask m), otherwise return 0. * If n is 0, they match if they are equal. If n is != 0, they match if they * are different. */ int pf_match_addr(u_int8_t n, u_int32_t a, u_int32_t m, u_int32_t b) { if ((a & m) == (b & m)) { if (n) return (0); else return (1); } else { if (n) return (1); else return (0); } } int pf_match_port(u_int8_t op, u_int16_t a1, u_int16_t a2, u_int16_t p) { NTOHS(a1); NTOHS(a2); NTOHS(p); switch (op) { case PF_OP_IRG: return (p > a1) && (p < a2); case PF_OP_XRG: 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 saddr, u_int32_t daddr) { struct pf_nat *n, *nm = NULL; n = TAILQ_FIRST(pf_nats_active); while (n && nm == NULL) { if (((n->ifp == NULL) || (n->ifp == ifp && !n->ifnot) || (n->ifp != ifp && n->ifnot)) && (!n->proto || n->proto == proto) && pf_match_addr(n->snot, n->saddr, n->smask, saddr) && pf_match_addr(n->dnot, n->daddr, n->dmask, daddr)) 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 saddr, u_int32_t daddr, u_int16_t dport) { struct pf_rdr *r, *rm = NULL; r = TAILQ_FIRST(pf_rdrs_active); while (r && rm == NULL) { if (((r->ifp == NULL) || (r->ifp == ifp && !r->ifnot) || (r->ifp != ifp && r->ifnot)) && (!r->proto || r->proto == proto) && pf_match_addr(r->snot, r->saddr, r->smask, saddr) && pf_match_addr(r->dnot, r->daddr, r->dmask, daddr) && ((!r->dport2 && dport == r->dport) || (r->dport2 && (ntohs(dport) >= ntohs(r->dport)) && ntohs(dport) <= ntohs(r->dport2)))) rm = r; else r = TAILQ_NEXT(r, entries); } return (rm); } 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, h->ip_dst.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->raddr, htons(pf_next_port_tcp)); rewrite++; } } else { /* check incoming packet for RDR */ if ((rdr = pf_get_rdr(ifp, IPPROTO_TCP, h->ip_src.s_addr, 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) && ((rm->rule_flag & PFRULE_RETURNRST) || rm->return_icmp)) { /* 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++; } if (rm->rule_flag & PFRULE_RETURNRST) pf_send_reset(h, off, th); else pf_send_icmp(m, rm->return_icmp >> 8, rm->return_icmp & 255); } 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; if (th->th_flags & TH_SYN) s->src.seqlo++; if (th->th_flags & TH_FIN) s->src.seqlo++; 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, h->ip_dst.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->raddr, htons(pf_next_port_udp)); rewrite++; } } else { /* check incoming packet for RDR */ if ((rdr = pf_get_rdr(ifp, IPPROTO_UDP, h->ip_src.s_addr, 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_DROP) && rm->return_icmp) { /* undo NAT/RST changes, if they have taken place */ if (nat != NULL) { pf_change_ap(&h->ip_src.s_addr, &uh->uh_sport, &h->ip_sum, &uh->uh_sum, baddr, bport); rewrite++; } else if (rdr != NULL) { pf_change_ap(&h->ip_dst.s_addr, &uh->uh_dport, &h->ip_sum, &uh->uh_sum, baddr, bport); rewrite++; } pf_send_icmp(m, rm->return_icmp >> 8, rm->return_icmp & 255); } 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 - sizeof(*uh); 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; if (direction == PF_OUT) { /* check outgoing packet for NAT */ if ((nat = pf_get_nat(ifp, IPPROTO_ICMP, h->ip_src.s_addr, h->ip_dst.s_addr)) != NULL) { baddr = h->ip_src.s_addr; pf_change_a(&h->ip_src.s_addr, &h->ip_sum, nat->raddr); } } 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 - ICMP_MINLEN; 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; if (nat != NULL) s->lan.addr = baddr; else s->lan.addr = 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); } 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); } int pf_test_state_tcp(struct pf_state **state, int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct tcphdr *th) { struct pf_tree_key key; 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; int ackskew; struct pf_state_peer *src, *dst; end = seq + len; if (th->th_flags & TH_SYN) end++; if (th->th_flags & TH_FIN) end++; 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; if (direction == PF_IN) *state = pf_find_state(tree_ext_gwy, &key); else *state = pf_find_state(tree_lan_ext, &key); if (*state == NULL) return (PF_DROP); if (direction == (*state)->direction) { src = &(*state)->src; dst = &(*state)->dst; } else { src = &(*state)->dst; dst = &(*state)->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 (src->state < 1) src->state = 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; } (*state)->packets++; (*state)->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) (*state)->expire = pftv.tv_sec + 5; else if (src->state >= 3 && dst->state >= 3) (*state)->expire = pftv.tv_sec + 300; else if (src->state < 2 || dst->state < 2) (*state)->expire = pftv.tv_sec + 30; else (*state)->expire = pftv.tv_sec + 24*60*60; /* translate source/destination address, if needed */ if ((*state)->lan.addr != (*state)->gwy.addr || (*state)->lan.port != (*state)->gwy.port) { if (direction == PF_OUT) pf_change_ap(&h->ip_src.s_addr, &th->th_sport, &h->ip_sum, &th->th_sum, (*state)->gwy.addr, (*state)->gwy.port); else pf_change_ap(&h->ip_dst.s_addr, &th->th_dport, &h->ip_sum, &th->th_sum, (*state)->lan.addr, (*state)->lan.port); m_copyback(m, off, sizeof(*th), (caddr_t)th); } return (PF_PASS); } else { /* XXX Remove these printfs before release */ printf("pf: BAD state: "); pf_print_state(direction, *state); 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'); return (PF_DROP); } } int pf_test_state_udp(struct pf_state **state, int direction, struct ifnet *ifp, struct mbuf *m, int ipoff, int off, struct ip *h, struct udphdr *uh) { u_int16_t len = h->ip_len - off - sizeof(*uh); struct pf_state_peer *src, *dst; struct pf_tree_key key; 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; if (direction == PF_IN) *state = pf_find_state(tree_ext_gwy, &key); else *state = pf_find_state(tree_lan_ext, &key); if (*state == NULL) return (PF_DROP); if (direction == (*state)->direction) { src = &(*state)->src; dst = &(*state)->dst; } else { src = &(*state)->dst; dst = &(*state)->src; } (*state)->packets++; (*state)->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) (*state)->expire = pftv.tv_sec + 60; else (*state)->expire = pftv.tv_sec + 20; /* translate source/destination address, if necessary */ if ((*state)->lan.addr != (*state)->gwy.addr || (*state)->lan.port != (*state)->gwy.port) { if (direction == PF_OUT) pf_change_ap(&h->ip_src.s_addr, &uh->uh_sport, &h->ip_sum, &uh->uh_sum, (*state)->gwy.addr, (*state)->gwy.port); else pf_change_ap(&h->ip_dst.s_addr, &uh->uh_dport, &h->ip_sum, &uh->uh_sum, (*state)->lan.addr, (*state)->lan.port); m_copyback(m, off, sizeof(*uh), (caddr_t)uh); } return (PF_PASS); } int pf_test_state_icmp(struct pf_state **state, 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); 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_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; if (direction == PF_IN) *state = pf_find_state(tree_ext_gwy, &key); else *state = pf_find_state(tree_lan_ext, &key); if (*state == NULL) return (PF_DROP); (*state)->packets++; (*state)->bytes += len; (*state)->expire = pftv.tv_sec + 10; /* translate source/destination address, if needed */ if ((*state)->lan.addr != (*state)->gwy.addr) { if (direction == PF_OUT) pf_change_a(&h->ip_src.s_addr, &h->ip_sum, (*state)->gwy.addr); else pf_change_a(&h->ip_dst.s_addr, &h->ip_sum, (*state)->lan.addr); } return (PF_PASS); } 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 + ICMP_MINLEN; /* offset of h2 in mbuf chain */ if (!pf_pull_hdr(m, ipoff2, &h2, sizeof(h2), NULL, NULL)) { printf("pf: ICMP error message too short (ip)\n"); return (PF_DROP); } /* ICMP error messages don't refer to non-first fragments */ if (h2.ip_off & IP_OFFMASK) return (PF_DROP); /* 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; 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(m, off2, &th, 8, NULL, NULL)) { printf("pf: " "ICMP error message too short (tcp)\n"); return (PF_DROP); } seq = ntohl(th.th_seq); 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; if (direction == PF_IN) *state = pf_find_state(tree_ext_gwy, &key); else *state = pf_find_state(tree_lan_ext, &key); if (*state == NULL) return (PF_DROP); if (direction == (*state)->direction) { src = &(*state)->dst; dst = &(*state)->src; } else { src = &(*state)->src; dst = &(*state)->dst; } if (!SEQ_GEQ(src->seqhi, seq) || !SEQ_GEQ(seq, src->seqlo - dst->max_win)) { printf("pf: BAD ICMP state: "); pf_print_state(direction, *state); printf(" seq=%lu\n", seq); return (PF_DROP); } if ((*state)->lan.addr != (*state)->gwy.addr || (*state)->lan.port != (*state)->gwy.port) { if (direction == PF_IN) { pf_change_icmp(&h2.ip_src.s_addr, &th.th_sport, &h->ip_dst.s_addr, (*state)->lan.addr, (*state)->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, (*state)->gwy.addr, (*state)->gwy.port, NULL, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } m_copyback(m, off, ICMP_MINLEN, (caddr_t)ih); m_copyback(m, ipoff2, sizeof(h2), (caddr_t)&h2); m_copyback(m, off2, 8, (caddr_t)&th); } return (PF_PASS); break; } case IPPROTO_UDP: { struct udphdr uh; struct pf_tree_key key; if (!pf_pull_hdr(m, off2, &uh, sizeof(uh), NULL, NULL)) { printf("pf: ICMP error message too short (udp)\n"); return (PF_DROP); } 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; if (direction == PF_IN) *state = pf_find_state(tree_ext_gwy, &key); else *state = pf_find_state(tree_lan_ext, &key); if (*state == NULL) return (PF_DROP); if ((*state)->lan.addr != (*state)->gwy.addr || (*state)->lan.port != (*state)->gwy.port) { if (direction == PF_IN) { pf_change_icmp(&h2.ip_src.s_addr, &uh.uh_sport, &h->ip_dst.s_addr, (*state)->lan.addr, (*state)->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, (*state)->gwy.addr, (*state)->gwy.port, &uh.uh_sum, &h2.ip_sum, &ih->icmp_cksum, &h->ip_sum); } m_copyback(m, off, ICMP_MINLEN, (caddr_t)ih); m_copyback(m, ipoff2, sizeof(h2), (caddr_t)&h2); m_copyback(m, off2, sizeof(uh), (caddr_t)&uh); } return (PF_PASS); break; } default: printf("pf: ICMP error message for bad proto\n"); 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 mbuf *m, int off, void *p, int len, u_short *actionp, u_short *reasonp) { struct ip *h = mtod(m, struct ip *); u_int16_t fragoff = (h->ip_off & IP_OFFMASK) << 3; 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 || 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 || (m_tag_find(m, PACKET_TAG_PF_GENERATED, NULL) != NULL)) 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; } /* We do IP header normalization and packet reassembly here */ if (pf_normalize_ip(m0, dir, ifp, &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(m, off, &th, sizeof(th), &action, &reason)) { log = action != PF_PASS; goto done; } action = pf_test_state_tcp(&s, dir, ifp, m, 0, off, h , &th); if (action == PF_PASS) { r = s->rule; log = s->log; } else if (s == NULL) action = pf_test_tcp(dir, ifp, m, 0, off, h , &th); break; } case IPPROTO_UDP: { struct udphdr uh; if (!pf_pull_hdr(m, off, &uh, sizeof(uh), &action, &reason)) { log = action != PF_PASS; goto done; } action = pf_test_state_udp(&s, dir, ifp, m, 0, off, h, &uh); if (action == PF_PASS) { r = s->rule; log = s->log; } else if (s == NULL) action = pf_test_udp(dir, ifp, m, 0, off, h, &uh); break; } case IPPROTO_ICMP: { struct icmp ih; if (!pf_pull_hdr(m, off, &ih, ICMP_MINLEN, &action, &reason)) { log = action != PF_PASS; goto done; } action = pf_test_state_icmp(&s, dir, ifp, m, 0, off, h, &ih); if (action == PF_PASS) { r = s->rule; log = s->log; } else if (s == NULL) action = pf_test_icmp(dir, ifp, m, 0, off, h, &ih); break; } default: action = pf_test_other(dir, ifp, m, h); break; } if (ifp == status_ifp) { pf_status.bcounters[dir] += h->ip_len; pf_status.pcounters[dir][action]++; } done: 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); }