/* $OpenBSD: pf_lb.c,v 1.2 2009/02/12 02:13:15 sthen Exp $ */ /* * Copyright (c) 2001 Daniel Hartmeier * Copyright (c) 2002 - 2008 Henning Brauer * 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. * * Effort sponsored in part by the Defense Advanced Research Projects * Agency (DARPA) and Air Force Research Laboratory, Air Force * Materiel Command, USAF, under agreement number F30602-01-2-0537. * */ #include __FBSDID("$FreeBSD$"); #include "opt_pf.h" #include "opt_inet.h" #include "opt_inet6.h" #include #include #include #include #include #include #include #define DPFPRINTF(n, x) if (V_pf_status.debug >= (n)) printf x static void pf_hash(struct pf_addr *, struct pf_addr *, struct pf_poolhashkey *, sa_family_t); static struct pf_rule *pf_match_translation(struct pf_pdesc *, struct mbuf *, int, int, struct pfi_kif *, struct pf_addr *, u_int16_t, struct pf_addr *, u_int16_t, int); static int pf_get_sport(sa_family_t, u_int8_t, struct pf_rule *, struct pf_addr *, struct pf_addr *, u_int16_t, struct pf_addr *, u_int16_t*, u_int16_t, u_int16_t, struct pf_src_node **); #define mix(a,b,c) \ do { \ a -= b; a -= c; a ^= (c >> 13); \ b -= c; b -= a; b ^= (a << 8); \ c -= a; c -= b; c ^= (b >> 13); \ a -= b; a -= c; a ^= (c >> 12); \ b -= c; b -= a; b ^= (a << 16); \ c -= a; c -= b; c ^= (b >> 5); \ a -= b; a -= c; a ^= (c >> 3); \ b -= c; b -= a; b ^= (a << 10); \ c -= a; c -= b; c ^= (b >> 15); \ } while (0) /* * hash function based on bridge_hash in if_bridge.c */ static void pf_hash(struct pf_addr *inaddr, struct pf_addr *hash, struct pf_poolhashkey *key, sa_family_t af) { u_int32_t a = 0x9e3779b9, b = 0x9e3779b9, c = key->key32[0]; switch (af) { #ifdef INET case AF_INET: a += inaddr->addr32[0]; b += key->key32[1]; mix(a, b, c); hash->addr32[0] = c + key->key32[2]; break; #endif /* INET */ #ifdef INET6 case AF_INET6: a += inaddr->addr32[0]; b += inaddr->addr32[2]; mix(a, b, c); hash->addr32[0] = c; a += inaddr->addr32[1]; b += inaddr->addr32[3]; c += key->key32[1]; mix(a, b, c); hash->addr32[1] = c; a += inaddr->addr32[2]; b += inaddr->addr32[1]; c += key->key32[2]; mix(a, b, c); hash->addr32[2] = c; a += inaddr->addr32[3]; b += inaddr->addr32[0]; c += key->key32[3]; mix(a, b, c); hash->addr32[3] = c; break; #endif /* INET6 */ } } static struct pf_rule * pf_match_translation(struct pf_pdesc *pd, struct mbuf *m, int off, int direction, struct pfi_kif *kif, struct pf_addr *saddr, u_int16_t sport, struct pf_addr *daddr, u_int16_t dport, int rs_num) { struct pf_rule *r, *rm = NULL; struct pf_ruleset *ruleset = NULL; int tag = -1; int rtableid = -1; int asd = 0; r = TAILQ_FIRST(pf_main_ruleset.rules[rs_num].active.ptr); while (r && rm == NULL) { struct pf_rule_addr *src = NULL, *dst = NULL; struct pf_addr_wrap *xdst = NULL; if (r->action == PF_BINAT && direction == PF_IN) { src = &r->dst; if (r->rpool.cur != NULL) xdst = &r->rpool.cur->addr; } else { src = &r->src; dst = &r->dst; } r->evaluations++; if (pfi_kif_match(r->kif, kif) == r->ifnot) r = r->skip[PF_SKIP_IFP].ptr; else if (r->direction && r->direction != direction) r = r->skip[PF_SKIP_DIR].ptr; else if (r->af && r->af != pd->af) r = r->skip[PF_SKIP_AF].ptr; else if (r->proto && r->proto != pd->proto) r = r->skip[PF_SKIP_PROTO].ptr; else if (PF_MISMATCHAW(&src->addr, saddr, pd->af, src->neg, kif, M_GETFIB(m))) r = r->skip[src == &r->src ? PF_SKIP_SRC_ADDR : PF_SKIP_DST_ADDR].ptr; else if (src->port_op && !pf_match_port(src->port_op, src->port[0], src->port[1], sport)) r = r->skip[src == &r->src ? PF_SKIP_SRC_PORT : PF_SKIP_DST_PORT].ptr; else if (dst != NULL && PF_MISMATCHAW(&dst->addr, daddr, pd->af, dst->neg, NULL, M_GETFIB(m))) r = r->skip[PF_SKIP_DST_ADDR].ptr; else if (xdst != NULL && PF_MISMATCHAW(xdst, daddr, pd->af, 0, NULL, M_GETFIB(m))) r = TAILQ_NEXT(r, entries); else if (dst != NULL && dst->port_op && !pf_match_port(dst->port_op, dst->port[0], dst->port[1], dport)) r = r->skip[PF_SKIP_DST_PORT].ptr; else if (r->match_tag && !pf_match_tag(m, r, &tag, pd->pf_mtag ? pd->pf_mtag->tag : 0)) r = TAILQ_NEXT(r, entries); else if (r->os_fingerprint != PF_OSFP_ANY && (pd->proto != IPPROTO_TCP || !pf_osfp_match(pf_osfp_fingerprint(pd, m, off, pd->hdr.tcp), r->os_fingerprint))) r = TAILQ_NEXT(r, entries); else { if (r->tag) tag = r->tag; if (r->rtableid >= 0) rtableid = r->rtableid; if (r->anchor == NULL) { rm = r; } else pf_step_into_anchor(&asd, &ruleset, rs_num, &r, NULL, NULL); } if (r == NULL) pf_step_out_of_anchor(&asd, &ruleset, rs_num, &r, NULL, NULL); } if (tag > 0 && pf_tag_packet(m, pd, tag)) return (NULL); if (rtableid >= 0) M_SETFIB(m, rtableid); if (rm != NULL && (rm->action == PF_NONAT || rm->action == PF_NORDR || rm->action == PF_NOBINAT)) return (NULL); return (rm); } static int pf_get_sport(sa_family_t af, u_int8_t proto, struct pf_rule *r, struct pf_addr *saddr, struct pf_addr *daddr, u_int16_t dport, struct pf_addr *naddr, u_int16_t *nport, u_int16_t low, u_int16_t high, struct pf_src_node **sn) { struct pf_state_key_cmp key; struct pf_addr init_addr; u_int16_t cut; bzero(&init_addr, sizeof(init_addr)); if (pf_map_addr(af, r, saddr, naddr, &init_addr, sn)) return (1); if (proto == IPPROTO_ICMP) { low = 1; high = 65535; } do { key.af = af; key.proto = proto; PF_ACPY(&key.addr[1], daddr, key.af); PF_ACPY(&key.addr[0], naddr, key.af); key.port[1] = dport; /* * port search; start random, step; * similar 2 portloop in in_pcbbind */ if (!(proto == IPPROTO_TCP || proto == IPPROTO_UDP || proto == IPPROTO_ICMP)) { key.port[0] = dport; if (pf_find_state_all(&key, PF_IN, NULL) == NULL) return (0); } else if (low == 0 && high == 0) { key.port[0] = *nport; if (pf_find_state_all(&key, PF_IN, NULL) == NULL) return (0); } else if (low == high) { key.port[0] = htons(low); if (pf_find_state_all(&key, PF_IN, NULL) == NULL) { *nport = htons(low); return (0); } } else { u_int16_t tmp; if (low > high) { tmp = low; low = high; high = tmp; } /* low < high */ cut = htonl(arc4random()) % (1 + high - low) + low; /* low <= cut <= high */ for (tmp = cut; tmp <= high; ++(tmp)) { key.port[0] = htons(tmp); if (pf_find_state_all(&key, PF_IN, NULL) == NULL) { *nport = htons(tmp); return (0); } } for (tmp = cut - 1; tmp >= low; --(tmp)) { key.port[0] = htons(tmp); if (pf_find_state_all(&key, PF_IN, NULL) == NULL) { *nport = htons(tmp); return (0); } } } switch (r->rpool.opts & PF_POOL_TYPEMASK) { case PF_POOL_RANDOM: case PF_POOL_ROUNDROBIN: if (pf_map_addr(af, r, saddr, naddr, &init_addr, sn)) return (1); break; case PF_POOL_NONE: case PF_POOL_SRCHASH: case PF_POOL_BITMASK: default: return (1); } } while (! PF_AEQ(&init_addr, naddr, af) ); return (1); /* none available */ } int pf_map_addr(sa_family_t af, struct pf_rule *r, struct pf_addr *saddr, struct pf_addr *naddr, struct pf_addr *init_addr, struct pf_src_node **sn) { struct pf_pool *rpool = &r->rpool; struct pf_addr *raddr = NULL, *rmask = NULL; if (*sn == NULL && r->rpool.opts & PF_POOL_STICKYADDR && (r->rpool.opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) { *sn = pf_find_src_node(saddr, r, af, 0); if (*sn != NULL && !PF_AZERO(&(*sn)->raddr, af)) { PF_ACPY(naddr, &(*sn)->raddr, af); if (V_pf_status.debug >= PF_DEBUG_MISC) { printf("pf_map_addr: src tracking maps "); pf_print_host(saddr, 0, af); printf(" to "); pf_print_host(naddr, 0, af); printf("\n"); } return (0); } } if (rpool->cur->addr.type == PF_ADDR_NOROUTE) return (1); if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) { switch (af) { #ifdef INET case AF_INET: if (rpool->cur->addr.p.dyn->pfid_acnt4 < 1 && (rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_ROUNDROBIN) return (1); raddr = &rpool->cur->addr.p.dyn->pfid_addr4; rmask = &rpool->cur->addr.p.dyn->pfid_mask4; break; #endif /* INET */ #ifdef INET6 case AF_INET6: if (rpool->cur->addr.p.dyn->pfid_acnt6 < 1 && (rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_ROUNDROBIN) return (1); raddr = &rpool->cur->addr.p.dyn->pfid_addr6; rmask = &rpool->cur->addr.p.dyn->pfid_mask6; break; #endif /* INET6 */ } } else if (rpool->cur->addr.type == PF_ADDR_TABLE) { if ((rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_ROUNDROBIN) return (1); /* unsupported */ } else { raddr = &rpool->cur->addr.v.a.addr; rmask = &rpool->cur->addr.v.a.mask; } switch (rpool->opts & PF_POOL_TYPEMASK) { case PF_POOL_NONE: PF_ACPY(naddr, raddr, af); break; case PF_POOL_BITMASK: PF_POOLMASK(naddr, raddr, rmask, saddr, af); break; case PF_POOL_RANDOM: if (init_addr != NULL && PF_AZERO(init_addr, af)) { switch (af) { #ifdef INET case AF_INET: rpool->counter.addr32[0] = htonl(arc4random()); break; #endif /* INET */ #ifdef INET6 case AF_INET6: if (rmask->addr32[3] != 0xffffffff) rpool->counter.addr32[3] = htonl(arc4random()); else break; if (rmask->addr32[2] != 0xffffffff) rpool->counter.addr32[2] = htonl(arc4random()); else break; if (rmask->addr32[1] != 0xffffffff) rpool->counter.addr32[1] = htonl(arc4random()); else break; if (rmask->addr32[0] != 0xffffffff) rpool->counter.addr32[0] = htonl(arc4random()); break; #endif /* INET6 */ } PF_POOLMASK(naddr, raddr, rmask, &rpool->counter, af); PF_ACPY(init_addr, naddr, af); } else { PF_AINC(&rpool->counter, af); PF_POOLMASK(naddr, raddr, rmask, &rpool->counter, af); } break; case PF_POOL_SRCHASH: { unsigned char hash[16]; pf_hash(saddr, (struct pf_addr *)&hash, &rpool->key, af); PF_POOLMASK(naddr, raddr, rmask, (struct pf_addr *)&hash, af); break; } case PF_POOL_ROUNDROBIN: { struct pf_pooladdr *acur = rpool->cur; /* * XXXGL: in the round-robin case we need to store * the round-robin machine state in the rule, thus * forwarding thread needs to modify rule. * * This is done w/o locking, because performance is assumed * more important than round-robin precision. * * In the simpliest case we just update the "rpool->cur" * pointer. However, if pool contains tables or dynamic * addresses, then "tblidx" is also used to store machine * state. Since "tblidx" is int, concurrent access to it can't * lead to inconsistence, only to lost of precision. * * Things get worse, if table contains not hosts, but * prefixes. In this case counter also stores machine state, * and for IPv6 address, counter can't be updated atomically. * Probably, using round-robin on a table containing IPv6 * prefixes (or even IPv4) would cause a panic. */ if (rpool->cur->addr.type == PF_ADDR_TABLE) { if (!pfr_pool_get(rpool->cur->addr.p.tbl, &rpool->tblidx, &rpool->counter, af)) goto get_addr; } else if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) { if (!pfr_pool_get(rpool->cur->addr.p.dyn->pfid_kt, &rpool->tblidx, &rpool->counter, af)) goto get_addr; } else if (pf_match_addr(0, raddr, rmask, &rpool->counter, af)) goto get_addr; try_next: if (TAILQ_NEXT(rpool->cur, entries) == NULL) rpool->cur = TAILQ_FIRST(&rpool->list); else rpool->cur = TAILQ_NEXT(rpool->cur, entries); if (rpool->cur->addr.type == PF_ADDR_TABLE) { rpool->tblidx = -1; if (pfr_pool_get(rpool->cur->addr.p.tbl, &rpool->tblidx, &rpool->counter, af)) { /* table contains no address of type 'af' */ if (rpool->cur != acur) goto try_next; return (1); } } else if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) { rpool->tblidx = -1; if (pfr_pool_get(rpool->cur->addr.p.dyn->pfid_kt, &rpool->tblidx, &rpool->counter, af)) { /* table contains no address of type 'af' */ if (rpool->cur != acur) goto try_next; return (1); } } else { raddr = &rpool->cur->addr.v.a.addr; rmask = &rpool->cur->addr.v.a.mask; PF_ACPY(&rpool->counter, raddr, af); } get_addr: PF_ACPY(naddr, &rpool->counter, af); if (init_addr != NULL && PF_AZERO(init_addr, af)) PF_ACPY(init_addr, naddr, af); PF_AINC(&rpool->counter, af); break; } } if (*sn != NULL) PF_ACPY(&(*sn)->raddr, naddr, af); if (V_pf_status.debug >= PF_DEBUG_MISC && (rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) { printf("pf_map_addr: selected address "); pf_print_host(naddr, 0, af); printf("\n"); } return (0); } struct pf_rule * pf_get_translation(struct pf_pdesc *pd, struct mbuf *m, int off, int direction, struct pfi_kif *kif, struct pf_src_node **sn, struct pf_state_key **skp, struct pf_state_key **nkp, struct pf_addr *saddr, struct pf_addr *daddr, u_int16_t sport, u_int16_t dport) { struct pf_rule *r = NULL; struct pf_addr *naddr; uint16_t *nport; PF_RULES_RASSERT(); KASSERT(*skp == NULL, ("*skp not NULL")); KASSERT(*nkp == NULL, ("*nkp not NULL")); if (direction == PF_OUT) { r = pf_match_translation(pd, m, off, direction, kif, saddr, sport, daddr, dport, PF_RULESET_BINAT); if (r == NULL) r = pf_match_translation(pd, m, off, direction, kif, saddr, sport, daddr, dport, PF_RULESET_NAT); } else { r = pf_match_translation(pd, m, off, direction, kif, saddr, sport, daddr, dport, PF_RULESET_RDR); if (r == NULL) r = pf_match_translation(pd, m, off, direction, kif, saddr, sport, daddr, dport, PF_RULESET_BINAT); } if (r == NULL) return (NULL); switch (r->action) { case PF_NONAT: case PF_NOBINAT: case PF_NORDR: return (NULL); } *skp = pf_state_key_setup(pd, saddr, daddr, sport, dport); if (*skp == NULL) return (NULL); *nkp = pf_state_key_clone(*skp); if (*nkp == NULL) { uma_zfree(V_pf_state_key_z, skp); *skp = NULL; return (NULL); } /* XXX We only modify one side for now. */ naddr = &(*nkp)->addr[1]; nport = &(*nkp)->port[1]; switch (r->action) { case PF_NAT: if (pf_get_sport(pd->af, pd->proto, r, saddr, daddr, dport, naddr, nport, r->rpool.proxy_port[0], r->rpool.proxy_port[1], sn)) { DPFPRINTF(PF_DEBUG_MISC, ("pf: NAT proxy port allocation (%u-%u) failed\n", r->rpool.proxy_port[0], r->rpool.proxy_port[1])); goto notrans; } break; case PF_BINAT: switch (direction) { case PF_OUT: if (r->rpool.cur->addr.type == PF_ADDR_DYNIFTL){ switch (pd->af) { #ifdef INET case AF_INET: if (r->rpool.cur->addr.p.dyn-> pfid_acnt4 < 1) goto notrans; PF_POOLMASK(naddr, &r->rpool.cur->addr.p.dyn-> pfid_addr4, &r->rpool.cur->addr.p.dyn-> pfid_mask4, saddr, AF_INET); break; #endif /* INET */ #ifdef INET6 case AF_INET6: if (r->rpool.cur->addr.p.dyn-> pfid_acnt6 < 1) goto notrans; PF_POOLMASK(naddr, &r->rpool.cur->addr.p.dyn-> pfid_addr6, &r->rpool.cur->addr.p.dyn-> pfid_mask6, saddr, AF_INET6); break; #endif /* INET6 */ } } else PF_POOLMASK(naddr, &r->rpool.cur->addr.v.a.addr, &r->rpool.cur->addr.v.a.mask, saddr, pd->af); break; case PF_IN: if (r->src.addr.type == PF_ADDR_DYNIFTL) { switch (pd->af) { #ifdef INET case AF_INET: if (r->src.addr.p.dyn-> pfid_acnt4 < 1) goto notrans; PF_POOLMASK(naddr, &r->src.addr.p.dyn->pfid_addr4, &r->src.addr.p.dyn->pfid_mask4, daddr, AF_INET); break; #endif /* INET */ #ifdef INET6 case AF_INET6: if (r->src.addr.p.dyn->pfid_acnt6 < 1) goto notrans; PF_POOLMASK(naddr, &r->src.addr.p.dyn->pfid_addr6, &r->src.addr.p.dyn->pfid_mask6, daddr, AF_INET6); break; #endif /* INET6 */ } } else PF_POOLMASK(naddr, &r->src.addr.v.a.addr, &r->src.addr.v.a.mask, daddr, pd->af); break; } break; case PF_RDR: { if (pf_map_addr(pd->af, r, saddr, naddr, NULL, sn)) goto notrans; if ((r->rpool.opts & PF_POOL_TYPEMASK) == PF_POOL_BITMASK) PF_POOLMASK(naddr, naddr, &r->rpool.cur->addr.v.a.mask, daddr, pd->af); if (r->rpool.proxy_port[1]) { uint32_t tmp_nport; tmp_nport = ((ntohs(dport) - ntohs(r->dst.port[0])) % (r->rpool.proxy_port[1] - r->rpool.proxy_port[0] + 1)) + r->rpool.proxy_port[0]; /* Wrap around if necessary. */ if (tmp_nport > 65535) tmp_nport -= 65535; *nport = htons((uint16_t)tmp_nport); } else if (r->rpool.proxy_port[0]) *nport = htons(r->rpool.proxy_port[0]); break; } default: panic("%s: unknown action %u", __func__, r->action); } /* Return success only if translation really happened. */ if (bcmp(*skp, *nkp, sizeof(struct pf_state_key_cmp))) return (r); notrans: uma_zfree(V_pf_state_key_z, *nkp); uma_zfree(V_pf_state_key_z, *skp); *skp = *nkp = NULL; return (NULL); }