1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002-2009 Luigi Rizzo, Universita` di Pisa 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 /* 32 * The FreeBSD IP packet firewall, main file 33 */ 34 35 #include "opt_ipfw.h" 36 #include "opt_ipdivert.h" 37 #include "opt_inet.h" 38 #ifndef INET 39 #error "IPFIREWALL requires INET" 40 #endif /* INET */ 41 #include "opt_inet6.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/condvar.h> 46 #include <sys/counter.h> 47 #include <sys/eventhandler.h> 48 #include <sys/malloc.h> 49 #include <sys/mbuf.h> 50 #include <sys/kernel.h> 51 #include <sys/lock.h> 52 #include <sys/jail.h> 53 #include <sys/module.h> 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/rwlock.h> 57 #include <sys/rmlock.h> 58 #include <sys/socket.h> 59 #include <sys/socketvar.h> 60 #include <sys/sysctl.h> 61 #include <sys/syslog.h> 62 #include <sys/ucred.h> 63 #include <net/ethernet.h> /* for ETHERTYPE_IP */ 64 #include <net/if.h> 65 #include <net/if_var.h> 66 #include <net/route.h> 67 #include <net/pfil.h> 68 #include <net/vnet.h> 69 70 #include <netpfil/pf/pf_mtag.h> 71 72 #include <netinet/in.h> 73 #include <netinet/in_var.h> 74 #include <netinet/in_pcb.h> 75 #include <netinet/ip.h> 76 #include <netinet/ip_var.h> 77 #include <netinet/ip_icmp.h> 78 #include <netinet/ip_fw.h> 79 #include <netinet/ip_carp.h> 80 #include <netinet/pim.h> 81 #include <netinet/tcp_var.h> 82 #include <netinet/udp.h> 83 #include <netinet/udp_var.h> 84 #include <netinet/sctp.h> 85 #include <netinet/sctp_crc32.h> 86 #include <netinet/sctp_header.h> 87 88 #include <netinet/ip6.h> 89 #include <netinet/icmp6.h> 90 #include <netinet/in_fib.h> 91 #ifdef INET6 92 #include <netinet6/in6_fib.h> 93 #include <netinet6/in6_pcb.h> 94 #include <netinet6/scope6_var.h> 95 #include <netinet6/ip6_var.h> 96 #endif 97 98 #include <net/if_gre.h> /* for struct grehdr */ 99 100 #include <netpfil/ipfw/ip_fw_private.h> 101 102 #include <machine/in_cksum.h> /* XXX for in_cksum */ 103 104 #ifdef MAC 105 #include <security/mac/mac_framework.h> 106 #endif 107 108 /* 109 * static variables followed by global ones. 110 * All ipfw global variables are here. 111 */ 112 113 VNET_DEFINE_STATIC(int, fw_deny_unknown_exthdrs); 114 #define V_fw_deny_unknown_exthdrs VNET(fw_deny_unknown_exthdrs) 115 116 VNET_DEFINE_STATIC(int, fw_permit_single_frag6) = 1; 117 #define V_fw_permit_single_frag6 VNET(fw_permit_single_frag6) 118 119 #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 120 static int default_to_accept = 1; 121 #else 122 static int default_to_accept; 123 #endif 124 125 VNET_DEFINE(int, autoinc_step); 126 VNET_DEFINE(int, fw_one_pass) = 1; 127 128 VNET_DEFINE(unsigned int, fw_tables_max); 129 VNET_DEFINE(unsigned int, fw_tables_sets) = 0; /* Don't use set-aware tables */ 130 /* Use 128 tables by default */ 131 static unsigned int default_fw_tables = IPFW_TABLES_DEFAULT; 132 133 #ifndef LINEAR_SKIPTO 134 static int jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 135 int tablearg, int jump_backwards); 136 #define JUMP(ch, f, num, targ, back) jump_fast(ch, f, num, targ, back) 137 #else 138 static int jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num, 139 int tablearg, int jump_backwards); 140 #define JUMP(ch, f, num, targ, back) jump_linear(ch, f, num, targ, back) 141 #endif 142 143 /* 144 * Each rule belongs to one of 32 different sets (0..31). 145 * The variable set_disable contains one bit per set. 146 * If the bit is set, all rules in the corresponding set 147 * are disabled. Set RESVD_SET(31) is reserved for the default rule 148 * and rules that are not deleted by the flush command, 149 * and CANNOT be disabled. 150 * Rules in set RESVD_SET can only be deleted individually. 151 */ 152 VNET_DEFINE(u_int32_t, set_disable); 153 #define V_set_disable VNET(set_disable) 154 155 VNET_DEFINE(int, fw_verbose); 156 /* counter for ipfw_log(NULL...) */ 157 VNET_DEFINE(u_int64_t, norule_counter); 158 VNET_DEFINE(int, verbose_limit); 159 160 /* layer3_chain contains the list of rules for layer 3 */ 161 VNET_DEFINE(struct ip_fw_chain, layer3_chain); 162 163 /* ipfw_vnet_ready controls when we are open for business */ 164 VNET_DEFINE(int, ipfw_vnet_ready) = 0; 165 166 VNET_DEFINE(int, ipfw_nat_ready) = 0; 167 168 ipfw_nat_t *ipfw_nat_ptr = NULL; 169 struct cfg_nat *(*lookup_nat_ptr)(struct nat_list *, int); 170 ipfw_nat_cfg_t *ipfw_nat_cfg_ptr; 171 ipfw_nat_cfg_t *ipfw_nat_del_ptr; 172 ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr; 173 ipfw_nat_cfg_t *ipfw_nat_get_log_ptr; 174 175 #ifdef SYSCTL_NODE 176 uint32_t dummy_def = IPFW_DEFAULT_RULE; 177 static int sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS); 178 static int sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS); 179 180 SYSBEGIN(f3) 181 182 SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 183 "Firewall"); 184 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 185 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_one_pass), 0, 186 "Only do a single pass through ipfw when using dummynet(4)"); 187 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, 188 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(autoinc_step), 0, 189 "Rule number auto-increment step"); 190 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, 191 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_verbose), 0, 192 "Log matches to ipfw rules"); 193 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, 194 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(verbose_limit), 0, 195 "Set upper limit of matches of ipfw rules logged"); 196 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, default_rule, CTLFLAG_RD, 197 &dummy_def, 0, 198 "The default/max possible rule number."); 199 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_max, 200 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, 201 0, 0, sysctl_ipfw_table_num, "IU", 202 "Maximum number of concurrently used tables"); 203 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_sets, 204 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, 205 0, 0, sysctl_ipfw_tables_sets, "IU", 206 "Use per-set namespace for tables"); 207 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, default_to_accept, CTLFLAG_RDTUN, 208 &default_to_accept, 0, 209 "Make the default rule accept all packets."); 210 TUNABLE_INT("net.inet.ip.fw.tables_max", (int *)&default_fw_tables); 211 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, 212 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(layer3_chain.n_rules), 0, 213 "Number of static rules"); 214 215 #ifdef INET6 216 SYSCTL_DECL(_net_inet6_ip6); 217 SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 218 "Firewall"); 219 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, deny_unknown_exthdrs, 220 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 221 &VNET_NAME(fw_deny_unknown_exthdrs), 0, 222 "Deny packets with unknown IPv6 Extension Headers"); 223 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, permit_single_frag6, 224 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 225 &VNET_NAME(fw_permit_single_frag6), 0, 226 "Permit single packet IPv6 fragments"); 227 #endif /* INET6 */ 228 229 SYSEND 230 231 #endif /* SYSCTL_NODE */ 232 233 234 /* 235 * Some macros used in the various matching options. 236 * L3HDR maps an ipv4 pointer into a layer3 header pointer of type T 237 * Other macros just cast void * into the appropriate type 238 */ 239 #define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 240 #define TCP(p) ((struct tcphdr *)(p)) 241 #define SCTP(p) ((struct sctphdr *)(p)) 242 #define UDP(p) ((struct udphdr *)(p)) 243 #define ICMP(p) ((struct icmphdr *)(p)) 244 #define ICMP6(p) ((struct icmp6_hdr *)(p)) 245 246 static __inline int 247 icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd) 248 { 249 int type = icmp->icmp_type; 250 251 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 252 } 253 254 #define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 255 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 256 257 static int 258 is_icmp_query(struct icmphdr *icmp) 259 { 260 int type = icmp->icmp_type; 261 262 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 263 } 264 #undef TT 265 266 /* 267 * The following checks use two arrays of 8 or 16 bits to store the 268 * bits that we want set or clear, respectively. They are in the 269 * low and high half of cmd->arg1 or cmd->d[0]. 270 * 271 * We scan options and store the bits we find set. We succeed if 272 * 273 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 274 * 275 * The code is sometimes optimized not to store additional variables. 276 */ 277 278 static int 279 flags_match(ipfw_insn *cmd, u_int8_t bits) 280 { 281 u_char want_clear; 282 bits = ~bits; 283 284 if ( ((cmd->arg1 & 0xff) & bits) != 0) 285 return 0; /* some bits we want set were clear */ 286 want_clear = (cmd->arg1 >> 8) & 0xff; 287 if ( (want_clear & bits) != want_clear) 288 return 0; /* some bits we want clear were set */ 289 return 1; 290 } 291 292 static int 293 ipopts_match(struct ip *ip, ipfw_insn *cmd) 294 { 295 int optlen, bits = 0; 296 u_char *cp = (u_char *)(ip + 1); 297 int x = (ip->ip_hl << 2) - sizeof (struct ip); 298 299 for (; x > 0; x -= optlen, cp += optlen) { 300 int opt = cp[IPOPT_OPTVAL]; 301 302 if (opt == IPOPT_EOL) 303 break; 304 if (opt == IPOPT_NOP) 305 optlen = 1; 306 else { 307 optlen = cp[IPOPT_OLEN]; 308 if (optlen <= 0 || optlen > x) 309 return 0; /* invalid or truncated */ 310 } 311 switch (opt) { 312 313 default: 314 break; 315 316 case IPOPT_LSRR: 317 bits |= IP_FW_IPOPT_LSRR; 318 break; 319 320 case IPOPT_SSRR: 321 bits |= IP_FW_IPOPT_SSRR; 322 break; 323 324 case IPOPT_RR: 325 bits |= IP_FW_IPOPT_RR; 326 break; 327 328 case IPOPT_TS: 329 bits |= IP_FW_IPOPT_TS; 330 break; 331 } 332 } 333 return (flags_match(cmd, bits)); 334 } 335 336 /* 337 * Parse TCP options. The logic copied from tcp_dooptions(). 338 */ 339 static int 340 tcpopts_parse(const struct tcphdr *tcp, uint16_t *mss) 341 { 342 const u_char *cp = (const u_char *)(tcp + 1); 343 int optlen, bits = 0; 344 int cnt = (tcp->th_off << 2) - sizeof(struct tcphdr); 345 346 for (; cnt > 0; cnt -= optlen, cp += optlen) { 347 int opt = cp[0]; 348 if (opt == TCPOPT_EOL) 349 break; 350 if (opt == TCPOPT_NOP) 351 optlen = 1; 352 else { 353 if (cnt < 2) 354 break; 355 optlen = cp[1]; 356 if (optlen < 2 || optlen > cnt) 357 break; 358 } 359 360 switch (opt) { 361 default: 362 break; 363 364 case TCPOPT_MAXSEG: 365 if (optlen != TCPOLEN_MAXSEG) 366 break; 367 bits |= IP_FW_TCPOPT_MSS; 368 if (mss != NULL) 369 *mss = be16dec(cp + 2); 370 break; 371 372 case TCPOPT_WINDOW: 373 if (optlen == TCPOLEN_WINDOW) 374 bits |= IP_FW_TCPOPT_WINDOW; 375 break; 376 377 case TCPOPT_SACK_PERMITTED: 378 if (optlen == TCPOLEN_SACK_PERMITTED) 379 bits |= IP_FW_TCPOPT_SACK; 380 break; 381 382 case TCPOPT_SACK: 383 if (optlen > 2 && (optlen - 2) % TCPOLEN_SACK == 0) 384 bits |= IP_FW_TCPOPT_SACK; 385 break; 386 387 case TCPOPT_TIMESTAMP: 388 if (optlen == TCPOLEN_TIMESTAMP) 389 bits |= IP_FW_TCPOPT_TS; 390 break; 391 } 392 } 393 return (bits); 394 } 395 396 static int 397 tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd) 398 { 399 400 return (flags_match(cmd, tcpopts_parse(tcp, NULL))); 401 } 402 403 static int 404 iface_match(struct ifnet *ifp, ipfw_insn_if *cmd, struct ip_fw_chain *chain, 405 uint32_t *tablearg) 406 { 407 408 if (ifp == NULL) /* no iface with this packet, match fails */ 409 return (0); 410 411 /* Check by name or by IP address */ 412 if (cmd->name[0] != '\0') { /* match by name */ 413 if (cmd->name[0] == '\1') /* use tablearg to match */ 414 return ipfw_lookup_table(chain, cmd->p.kidx, 0, 415 &ifp->if_index, tablearg); 416 /* Check name */ 417 if (cmd->p.glob) { 418 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 419 return(1); 420 } else { 421 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 422 return(1); 423 } 424 } else { 425 #if !defined(USERSPACE) && defined(__FreeBSD__) /* and OSX too ? */ 426 struct ifaddr *ia; 427 428 NET_EPOCH_ASSERT(); 429 430 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 431 if (ia->ifa_addr->sa_family != AF_INET) 432 continue; 433 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 434 (ia->ifa_addr))->sin_addr.s_addr) 435 return (1); /* match */ 436 } 437 #endif /* __FreeBSD__ */ 438 } 439 return(0); /* no match, fail ... */ 440 } 441 442 /* 443 * The verify_path function checks if a route to the src exists and 444 * if it is reachable via ifp (when provided). 445 * 446 * The 'verrevpath' option checks that the interface that an IP packet 447 * arrives on is the same interface that traffic destined for the 448 * packet's source address would be routed out of. 449 * The 'versrcreach' option just checks that the source address is 450 * reachable via any route (except default) in the routing table. 451 * These two are a measure to block forged packets. This is also 452 * commonly known as "anti-spoofing" or Unicast Reverse Path 453 * Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 454 * is purposely reminiscent of the Cisco IOS command, 455 * 456 * ip verify unicast reverse-path 457 * ip verify unicast source reachable-via any 458 * 459 * which implements the same functionality. But note that the syntax 460 * is misleading, and the check may be performed on all IP packets 461 * whether unicast, multicast, or broadcast. 462 */ 463 static int 464 verify_path(struct in_addr src, struct ifnet *ifp, u_int fib) 465 { 466 #if defined(USERSPACE) || !defined(__FreeBSD__) 467 return 0; 468 #else 469 struct nhop4_basic nh4; 470 471 if (fib4_lookup_nh_basic(fib, src, NHR_IFAIF, 0, &nh4) != 0) 472 return (0); 473 474 /* 475 * If ifp is provided, check for equality with rtentry. 476 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 477 * in order to pass packets injected back by if_simloop(): 478 * routing entry (via lo0) for our own address 479 * may exist, so we need to handle routing assymetry. 480 */ 481 if (ifp != NULL && ifp != nh4.nh_ifp) 482 return (0); 483 484 /* if no ifp provided, check if rtentry is not default route */ 485 if (ifp == NULL && (nh4.nh_flags & NHF_DEFAULT) != 0) 486 return (0); 487 488 /* or if this is a blackhole/reject route */ 489 if (ifp == NULL && (nh4.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 490 return (0); 491 492 /* found valid route */ 493 return 1; 494 #endif /* __FreeBSD__ */ 495 } 496 497 /* 498 * Generate an SCTP packet containing an ABORT chunk. The verification tag 499 * is given by vtag. The T-bit is set in the ABORT chunk if and only if 500 * reflected is not 0. 501 */ 502 503 static struct mbuf * 504 ipfw_send_abort(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t vtag, 505 int reflected) 506 { 507 struct mbuf *m; 508 struct ip *ip; 509 #ifdef INET6 510 struct ip6_hdr *ip6; 511 #endif 512 struct sctphdr *sctp; 513 struct sctp_chunkhdr *chunk; 514 u_int16_t hlen, plen, tlen; 515 516 MGETHDR(m, M_NOWAIT, MT_DATA); 517 if (m == NULL) 518 return (NULL); 519 520 M_SETFIB(m, id->fib); 521 #ifdef MAC 522 if (replyto != NULL) 523 mac_netinet_firewall_reply(replyto, m); 524 else 525 mac_netinet_firewall_send(m); 526 #else 527 (void)replyto; /* don't warn about unused arg */ 528 #endif 529 530 switch (id->addr_type) { 531 case 4: 532 hlen = sizeof(struct ip); 533 break; 534 #ifdef INET6 535 case 6: 536 hlen = sizeof(struct ip6_hdr); 537 break; 538 #endif 539 default: 540 /* XXX: log me?!? */ 541 FREE_PKT(m); 542 return (NULL); 543 } 544 plen = sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr); 545 tlen = hlen + plen; 546 m->m_data += max_linkhdr; 547 m->m_flags |= M_SKIP_FIREWALL; 548 m->m_pkthdr.len = m->m_len = tlen; 549 m->m_pkthdr.rcvif = NULL; 550 bzero(m->m_data, tlen); 551 552 switch (id->addr_type) { 553 case 4: 554 ip = mtod(m, struct ip *); 555 556 ip->ip_v = 4; 557 ip->ip_hl = sizeof(struct ip) >> 2; 558 ip->ip_tos = IPTOS_LOWDELAY; 559 ip->ip_len = htons(tlen); 560 ip->ip_id = htons(0); 561 ip->ip_off = htons(0); 562 ip->ip_ttl = V_ip_defttl; 563 ip->ip_p = IPPROTO_SCTP; 564 ip->ip_sum = 0; 565 ip->ip_src.s_addr = htonl(id->dst_ip); 566 ip->ip_dst.s_addr = htonl(id->src_ip); 567 568 sctp = (struct sctphdr *)(ip + 1); 569 break; 570 #ifdef INET6 571 case 6: 572 ip6 = mtod(m, struct ip6_hdr *); 573 574 ip6->ip6_vfc = IPV6_VERSION; 575 ip6->ip6_plen = htons(plen); 576 ip6->ip6_nxt = IPPROTO_SCTP; 577 ip6->ip6_hlim = IPV6_DEFHLIM; 578 ip6->ip6_src = id->dst_ip6; 579 ip6->ip6_dst = id->src_ip6; 580 581 sctp = (struct sctphdr *)(ip6 + 1); 582 break; 583 #endif 584 } 585 586 sctp->src_port = htons(id->dst_port); 587 sctp->dest_port = htons(id->src_port); 588 sctp->v_tag = htonl(vtag); 589 sctp->checksum = htonl(0); 590 591 chunk = (struct sctp_chunkhdr *)(sctp + 1); 592 chunk->chunk_type = SCTP_ABORT_ASSOCIATION; 593 chunk->chunk_flags = 0; 594 if (reflected != 0) { 595 chunk->chunk_flags |= SCTP_HAD_NO_TCB; 596 } 597 chunk->chunk_length = htons(sizeof(struct sctp_chunkhdr)); 598 599 sctp->checksum = sctp_calculate_cksum(m, hlen); 600 601 return (m); 602 } 603 604 /* 605 * Generate a TCP packet, containing either a RST or a keepalive. 606 * When flags & TH_RST, we are sending a RST packet, because of a 607 * "reset" action matched the packet. 608 * Otherwise we are sending a keepalive, and flags & TH_ 609 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 610 * so that MAC can label the reply appropriately. 611 */ 612 struct mbuf * 613 ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 614 u_int32_t ack, int flags) 615 { 616 struct mbuf *m = NULL; /* stupid compiler */ 617 struct ip *h = NULL; /* stupid compiler */ 618 #ifdef INET6 619 struct ip6_hdr *h6 = NULL; 620 #endif 621 struct tcphdr *th = NULL; 622 int len, dir; 623 624 MGETHDR(m, M_NOWAIT, MT_DATA); 625 if (m == NULL) 626 return (NULL); 627 628 M_SETFIB(m, id->fib); 629 #ifdef MAC 630 if (replyto != NULL) 631 mac_netinet_firewall_reply(replyto, m); 632 else 633 mac_netinet_firewall_send(m); 634 #else 635 (void)replyto; /* don't warn about unused arg */ 636 #endif 637 638 switch (id->addr_type) { 639 case 4: 640 len = sizeof(struct ip) + sizeof(struct tcphdr); 641 break; 642 #ifdef INET6 643 case 6: 644 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 645 break; 646 #endif 647 default: 648 /* XXX: log me?!? */ 649 FREE_PKT(m); 650 return (NULL); 651 } 652 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 653 654 m->m_data += max_linkhdr; 655 m->m_flags |= M_SKIP_FIREWALL; 656 m->m_pkthdr.len = m->m_len = len; 657 m->m_pkthdr.rcvif = NULL; 658 bzero(m->m_data, len); 659 660 switch (id->addr_type) { 661 case 4: 662 h = mtod(m, struct ip *); 663 664 /* prepare for checksum */ 665 h->ip_p = IPPROTO_TCP; 666 h->ip_len = htons(sizeof(struct tcphdr)); 667 if (dir) { 668 h->ip_src.s_addr = htonl(id->src_ip); 669 h->ip_dst.s_addr = htonl(id->dst_ip); 670 } else { 671 h->ip_src.s_addr = htonl(id->dst_ip); 672 h->ip_dst.s_addr = htonl(id->src_ip); 673 } 674 675 th = (struct tcphdr *)(h + 1); 676 break; 677 #ifdef INET6 678 case 6: 679 h6 = mtod(m, struct ip6_hdr *); 680 681 /* prepare for checksum */ 682 h6->ip6_nxt = IPPROTO_TCP; 683 h6->ip6_plen = htons(sizeof(struct tcphdr)); 684 if (dir) { 685 h6->ip6_src = id->src_ip6; 686 h6->ip6_dst = id->dst_ip6; 687 } else { 688 h6->ip6_src = id->dst_ip6; 689 h6->ip6_dst = id->src_ip6; 690 } 691 692 th = (struct tcphdr *)(h6 + 1); 693 break; 694 #endif 695 } 696 697 if (dir) { 698 th->th_sport = htons(id->src_port); 699 th->th_dport = htons(id->dst_port); 700 } else { 701 th->th_sport = htons(id->dst_port); 702 th->th_dport = htons(id->src_port); 703 } 704 th->th_off = sizeof(struct tcphdr) >> 2; 705 706 if (flags & TH_RST) { 707 if (flags & TH_ACK) { 708 th->th_seq = htonl(ack); 709 th->th_flags = TH_RST; 710 } else { 711 if (flags & TH_SYN) 712 seq++; 713 th->th_ack = htonl(seq); 714 th->th_flags = TH_RST | TH_ACK; 715 } 716 } else { 717 /* 718 * Keepalive - use caller provided sequence numbers 719 */ 720 th->th_seq = htonl(seq); 721 th->th_ack = htonl(ack); 722 th->th_flags = TH_ACK; 723 } 724 725 switch (id->addr_type) { 726 case 4: 727 th->th_sum = in_cksum(m, len); 728 729 /* finish the ip header */ 730 h->ip_v = 4; 731 h->ip_hl = sizeof(*h) >> 2; 732 h->ip_tos = IPTOS_LOWDELAY; 733 h->ip_off = htons(0); 734 h->ip_len = htons(len); 735 h->ip_ttl = V_ip_defttl; 736 h->ip_sum = 0; 737 break; 738 #ifdef INET6 739 case 6: 740 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 741 sizeof(struct tcphdr)); 742 743 /* finish the ip6 header */ 744 h6->ip6_vfc |= IPV6_VERSION; 745 h6->ip6_hlim = IPV6_DEFHLIM; 746 break; 747 #endif 748 } 749 750 return (m); 751 } 752 753 #ifdef INET6 754 /* 755 * ipv6 specific rules here... 756 */ 757 static __inline int 758 icmp6type_match (int type, ipfw_insn_u32 *cmd) 759 { 760 return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) ); 761 } 762 763 static int 764 flow6id_match( int curr_flow, ipfw_insn_u32 *cmd ) 765 { 766 int i; 767 for (i=0; i <= cmd->o.arg1; ++i ) 768 if (curr_flow == cmd->d[i] ) 769 return 1; 770 return 0; 771 } 772 773 /* support for IP6_*_ME opcodes */ 774 static const struct in6_addr lla_mask = {{{ 775 0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 776 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff 777 }}}; 778 779 static int 780 ipfw_localip6(struct in6_addr *in6) 781 { 782 struct rm_priotracker in6_ifa_tracker; 783 struct in6_ifaddr *ia; 784 785 if (IN6_IS_ADDR_MULTICAST(in6)) 786 return (0); 787 788 if (!IN6_IS_ADDR_LINKLOCAL(in6)) 789 return (in6_localip(in6)); 790 791 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 792 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 793 if (!IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) 794 continue; 795 if (IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr, 796 in6, &lla_mask)) { 797 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 798 return (1); 799 } 800 } 801 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 802 return (0); 803 } 804 805 static int 806 verify_path6(struct in6_addr *src, struct ifnet *ifp, u_int fib) 807 { 808 struct nhop6_basic nh6; 809 810 if (IN6_IS_SCOPE_LINKLOCAL(src)) 811 return (1); 812 813 if (fib6_lookup_nh_basic(fib, src, 0, NHR_IFAIF, 0, &nh6) != 0) 814 return (0); 815 816 /* If ifp is provided, check for equality with route table. */ 817 if (ifp != NULL && ifp != nh6.nh_ifp) 818 return (0); 819 820 /* if no ifp provided, check if rtentry is not default route */ 821 if (ifp == NULL && (nh6.nh_flags & NHF_DEFAULT) != 0) 822 return (0); 823 824 /* or if this is a blackhole/reject route */ 825 if (ifp == NULL && (nh6.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 826 return (0); 827 828 /* found valid route */ 829 return 1; 830 } 831 832 static int 833 is_icmp6_query(int icmp6_type) 834 { 835 if ((icmp6_type <= ICMP6_MAXTYPE) && 836 (icmp6_type == ICMP6_ECHO_REQUEST || 837 icmp6_type == ICMP6_MEMBERSHIP_QUERY || 838 icmp6_type == ICMP6_WRUREQUEST || 839 icmp6_type == ICMP6_FQDN_QUERY || 840 icmp6_type == ICMP6_NI_QUERY)) 841 return (1); 842 843 return (0); 844 } 845 846 static int 847 map_icmp_unreach(int code) 848 { 849 850 /* RFC 7915 p4.2 */ 851 switch (code) { 852 case ICMP_UNREACH_NET: 853 case ICMP_UNREACH_HOST: 854 case ICMP_UNREACH_SRCFAIL: 855 case ICMP_UNREACH_NET_UNKNOWN: 856 case ICMP_UNREACH_HOST_UNKNOWN: 857 case ICMP_UNREACH_TOSNET: 858 case ICMP_UNREACH_TOSHOST: 859 return (ICMP6_DST_UNREACH_NOROUTE); 860 case ICMP_UNREACH_PORT: 861 return (ICMP6_DST_UNREACH_NOPORT); 862 default: 863 /* 864 * Map the rest of codes into admit prohibited. 865 * XXX: unreach proto should be mapped into ICMPv6 866 * parameter problem, but we use only unreach type. 867 */ 868 return (ICMP6_DST_UNREACH_ADMIN); 869 } 870 } 871 872 static void 873 send_reject6(struct ip_fw_args *args, int code, u_int hlen, struct ip6_hdr *ip6) 874 { 875 struct mbuf *m; 876 877 m = args->m; 878 if (code == ICMP6_UNREACH_RST && args->f_id.proto == IPPROTO_TCP) { 879 struct tcphdr *tcp; 880 tcp = (struct tcphdr *)((char *)ip6 + hlen); 881 882 if ((tcp->th_flags & TH_RST) == 0) { 883 struct mbuf *m0; 884 m0 = ipfw_send_pkt(args->m, &(args->f_id), 885 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 886 tcp->th_flags | TH_RST); 887 if (m0 != NULL) 888 ip6_output(m0, NULL, NULL, 0, NULL, NULL, 889 NULL); 890 } 891 FREE_PKT(m); 892 } else if (code == ICMP6_UNREACH_ABORT && 893 args->f_id.proto == IPPROTO_SCTP) { 894 struct mbuf *m0; 895 struct sctphdr *sctp; 896 u_int32_t v_tag; 897 int reflected; 898 899 sctp = (struct sctphdr *)((char *)ip6 + hlen); 900 reflected = 1; 901 v_tag = ntohl(sctp->v_tag); 902 /* Investigate the first chunk header if available */ 903 if (m->m_len >= hlen + sizeof(struct sctphdr) + 904 sizeof(struct sctp_chunkhdr)) { 905 struct sctp_chunkhdr *chunk; 906 907 chunk = (struct sctp_chunkhdr *)(sctp + 1); 908 switch (chunk->chunk_type) { 909 case SCTP_INITIATION: 910 /* 911 * Packets containing an INIT chunk MUST have 912 * a zero v-tag. 913 */ 914 if (v_tag != 0) { 915 v_tag = 0; 916 break; 917 } 918 /* INIT chunk MUST NOT be bundled */ 919 if (m->m_pkthdr.len > 920 hlen + sizeof(struct sctphdr) + 921 ntohs(chunk->chunk_length) + 3) { 922 break; 923 } 924 /* Use the initiate tag if available */ 925 if ((m->m_len >= hlen + sizeof(struct sctphdr) + 926 sizeof(struct sctp_chunkhdr) + 927 offsetof(struct sctp_init, a_rwnd))) { 928 struct sctp_init *init; 929 930 init = (struct sctp_init *)(chunk + 1); 931 v_tag = ntohl(init->initiate_tag); 932 reflected = 0; 933 } 934 break; 935 case SCTP_ABORT_ASSOCIATION: 936 /* 937 * If the packet contains an ABORT chunk, don't 938 * reply. 939 * XXX: We should search through all chunks, 940 * but do not do that to avoid attacks. 941 */ 942 v_tag = 0; 943 break; 944 } 945 } 946 if (v_tag == 0) { 947 m0 = NULL; 948 } else { 949 m0 = ipfw_send_abort(args->m, &(args->f_id), v_tag, 950 reflected); 951 } 952 if (m0 != NULL) 953 ip6_output(m0, NULL, NULL, 0, NULL, NULL, NULL); 954 FREE_PKT(m); 955 } else if (code != ICMP6_UNREACH_RST && code != ICMP6_UNREACH_ABORT) { 956 /* Send an ICMPv6 unreach. */ 957 #if 0 958 /* 959 * Unlike above, the mbufs need to line up with the ip6 hdr, 960 * as the contents are read. We need to m_adj() the 961 * needed amount. 962 * The mbuf will however be thrown away so we can adjust it. 963 * Remember we did an m_pullup on it already so we 964 * can make some assumptions about contiguousness. 965 */ 966 if (args->L3offset) 967 m_adj(m, args->L3offset); 968 #endif 969 icmp6_error(m, ICMP6_DST_UNREACH, code, 0); 970 } else 971 FREE_PKT(m); 972 973 args->m = NULL; 974 } 975 976 #endif /* INET6 */ 977 978 979 /* 980 * sends a reject message, consuming the mbuf passed as an argument. 981 */ 982 static void 983 send_reject(struct ip_fw_args *args, int code, int iplen, struct ip *ip) 984 { 985 986 #if 0 987 /* XXX When ip is not guaranteed to be at mtod() we will 988 * need to account for this */ 989 * The mbuf will however be thrown away so we can adjust it. 990 * Remember we did an m_pullup on it already so we 991 * can make some assumptions about contiguousness. 992 */ 993 if (args->L3offset) 994 m_adj(m, args->L3offset); 995 #endif 996 if (code != ICMP_REJECT_RST && code != ICMP_REJECT_ABORT) { 997 /* Send an ICMP unreach */ 998 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 999 } else if (code == ICMP_REJECT_RST && args->f_id.proto == IPPROTO_TCP) { 1000 struct tcphdr *const tcp = 1001 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 1002 if ( (tcp->th_flags & TH_RST) == 0) { 1003 struct mbuf *m; 1004 m = ipfw_send_pkt(args->m, &(args->f_id), 1005 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 1006 tcp->th_flags | TH_RST); 1007 if (m != NULL) 1008 ip_output(m, NULL, NULL, 0, NULL, NULL); 1009 } 1010 FREE_PKT(args->m); 1011 } else if (code == ICMP_REJECT_ABORT && 1012 args->f_id.proto == IPPROTO_SCTP) { 1013 struct mbuf *m; 1014 struct sctphdr *sctp; 1015 struct sctp_chunkhdr *chunk; 1016 struct sctp_init *init; 1017 u_int32_t v_tag; 1018 int reflected; 1019 1020 sctp = L3HDR(struct sctphdr, mtod(args->m, struct ip *)); 1021 reflected = 1; 1022 v_tag = ntohl(sctp->v_tag); 1023 if (iplen >= (ip->ip_hl << 2) + sizeof(struct sctphdr) + 1024 sizeof(struct sctp_chunkhdr)) { 1025 /* Look at the first chunk header if available */ 1026 chunk = (struct sctp_chunkhdr *)(sctp + 1); 1027 switch (chunk->chunk_type) { 1028 case SCTP_INITIATION: 1029 /* 1030 * Packets containing an INIT chunk MUST have 1031 * a zero v-tag. 1032 */ 1033 if (v_tag != 0) { 1034 v_tag = 0; 1035 break; 1036 } 1037 /* INIT chunk MUST NOT be bundled */ 1038 if (iplen > 1039 (ip->ip_hl << 2) + sizeof(struct sctphdr) + 1040 ntohs(chunk->chunk_length) + 3) { 1041 break; 1042 } 1043 /* Use the initiate tag if available */ 1044 if ((iplen >= (ip->ip_hl << 2) + 1045 sizeof(struct sctphdr) + 1046 sizeof(struct sctp_chunkhdr) + 1047 offsetof(struct sctp_init, a_rwnd))) { 1048 init = (struct sctp_init *)(chunk + 1); 1049 v_tag = ntohl(init->initiate_tag); 1050 reflected = 0; 1051 } 1052 break; 1053 case SCTP_ABORT_ASSOCIATION: 1054 /* 1055 * If the packet contains an ABORT chunk, don't 1056 * reply. 1057 * XXX: We should search through all chunks, 1058 * but do not do that to avoid attacks. 1059 */ 1060 v_tag = 0; 1061 break; 1062 } 1063 } 1064 if (v_tag == 0) { 1065 m = NULL; 1066 } else { 1067 m = ipfw_send_abort(args->m, &(args->f_id), v_tag, 1068 reflected); 1069 } 1070 if (m != NULL) 1071 ip_output(m, NULL, NULL, 0, NULL, NULL); 1072 FREE_PKT(args->m); 1073 } else 1074 FREE_PKT(args->m); 1075 args->m = NULL; 1076 } 1077 1078 /* 1079 * Support for uid/gid/jail lookup. These tests are expensive 1080 * (because we may need to look into the list of active sockets) 1081 * so we cache the results. ugid_lookupp is 0 if we have not 1082 * yet done a lookup, 1 if we succeeded, and -1 if we tried 1083 * and failed. The function always returns the match value. 1084 * We could actually spare the variable and use *uc, setting 1085 * it to '(void *)check_uidgid if we have no info, NULL if 1086 * we tried and failed, or any other value if successful. 1087 */ 1088 static int 1089 check_uidgid(ipfw_insn_u32 *insn, struct ip_fw_args *args, int *ugid_lookupp, 1090 struct ucred **uc) 1091 { 1092 #if defined(USERSPACE) 1093 return 0; // not supported in userspace 1094 #else 1095 #ifndef __FreeBSD__ 1096 /* XXX */ 1097 return cred_check(insn, proto, oif, 1098 dst_ip, dst_port, src_ip, src_port, 1099 (struct bsd_ucred *)uc, ugid_lookupp, ((struct mbuf *)inp)->m_skb); 1100 #else /* FreeBSD */ 1101 struct in_addr src_ip, dst_ip; 1102 struct inpcbinfo *pi; 1103 struct ipfw_flow_id *id; 1104 struct inpcb *pcb, *inp; 1105 int lookupflags; 1106 int match; 1107 1108 id = &args->f_id; 1109 inp = args->inp; 1110 1111 /* 1112 * Check to see if the UDP or TCP stack supplied us with 1113 * the PCB. If so, rather then holding a lock and looking 1114 * up the PCB, we can use the one that was supplied. 1115 */ 1116 if (inp && *ugid_lookupp == 0) { 1117 INP_LOCK_ASSERT(inp); 1118 if (inp->inp_socket != NULL) { 1119 *uc = crhold(inp->inp_cred); 1120 *ugid_lookupp = 1; 1121 } else 1122 *ugid_lookupp = -1; 1123 } 1124 /* 1125 * If we have already been here and the packet has no 1126 * PCB entry associated with it, then we can safely 1127 * assume that this is a no match. 1128 */ 1129 if (*ugid_lookupp == -1) 1130 return (0); 1131 if (id->proto == IPPROTO_TCP) { 1132 lookupflags = 0; 1133 pi = &V_tcbinfo; 1134 } else if (id->proto == IPPROTO_UDP) { 1135 lookupflags = INPLOOKUP_WILDCARD; 1136 pi = &V_udbinfo; 1137 } else if (id->proto == IPPROTO_UDPLITE) { 1138 lookupflags = INPLOOKUP_WILDCARD; 1139 pi = &V_ulitecbinfo; 1140 } else 1141 return 0; 1142 lookupflags |= INPLOOKUP_RLOCKPCB; 1143 match = 0; 1144 if (*ugid_lookupp == 0) { 1145 if (id->addr_type == 6) { 1146 #ifdef INET6 1147 if (args->flags & IPFW_ARGS_IN) 1148 pcb = in6_pcblookup_mbuf(pi, 1149 &id->src_ip6, htons(id->src_port), 1150 &id->dst_ip6, htons(id->dst_port), 1151 lookupflags, NULL, args->m); 1152 else 1153 pcb = in6_pcblookup_mbuf(pi, 1154 &id->dst_ip6, htons(id->dst_port), 1155 &id->src_ip6, htons(id->src_port), 1156 lookupflags, args->ifp, args->m); 1157 #else 1158 *ugid_lookupp = -1; 1159 return (0); 1160 #endif 1161 } else { 1162 src_ip.s_addr = htonl(id->src_ip); 1163 dst_ip.s_addr = htonl(id->dst_ip); 1164 if (args->flags & IPFW_ARGS_IN) 1165 pcb = in_pcblookup_mbuf(pi, 1166 src_ip, htons(id->src_port), 1167 dst_ip, htons(id->dst_port), 1168 lookupflags, NULL, args->m); 1169 else 1170 pcb = in_pcblookup_mbuf(pi, 1171 dst_ip, htons(id->dst_port), 1172 src_ip, htons(id->src_port), 1173 lookupflags, args->ifp, args->m); 1174 } 1175 if (pcb != NULL) { 1176 INP_RLOCK_ASSERT(pcb); 1177 *uc = crhold(pcb->inp_cred); 1178 *ugid_lookupp = 1; 1179 INP_RUNLOCK(pcb); 1180 } 1181 if (*ugid_lookupp == 0) { 1182 /* 1183 * We tried and failed, set the variable to -1 1184 * so we will not try again on this packet. 1185 */ 1186 *ugid_lookupp = -1; 1187 return (0); 1188 } 1189 } 1190 if (insn->o.opcode == O_UID) 1191 match = ((*uc)->cr_uid == (uid_t)insn->d[0]); 1192 else if (insn->o.opcode == O_GID) 1193 match = groupmember((gid_t)insn->d[0], *uc); 1194 else if (insn->o.opcode == O_JAIL) 1195 match = ((*uc)->cr_prison->pr_id == (int)insn->d[0]); 1196 return (match); 1197 #endif /* __FreeBSD__ */ 1198 #endif /* not supported in userspace */ 1199 } 1200 1201 /* 1202 * Helper function to set args with info on the rule after the matching 1203 * one. slot is precise, whereas we guess rule_id as they are 1204 * assigned sequentially. 1205 */ 1206 static inline void 1207 set_match(struct ip_fw_args *args, int slot, 1208 struct ip_fw_chain *chain) 1209 { 1210 args->rule.chain_id = chain->id; 1211 args->rule.slot = slot + 1; /* we use 0 as a marker */ 1212 args->rule.rule_id = 1 + chain->map[slot]->id; 1213 args->rule.rulenum = chain->map[slot]->rulenum; 1214 args->flags |= IPFW_ARGS_REF; 1215 } 1216 1217 #ifndef LINEAR_SKIPTO 1218 /* 1219 * Helper function to enable cached rule lookups using 1220 * cached_id and cached_pos fields in ipfw rule. 1221 */ 1222 static int 1223 jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 1224 int tablearg, int jump_backwards) 1225 { 1226 int f_pos; 1227 1228 /* If possible use cached f_pos (in f->cached_pos), 1229 * whose version is written in f->cached_id 1230 * (horrible hacks to avoid changing the ABI). 1231 */ 1232 if (num != IP_FW_TARG && f->cached_id == chain->id) 1233 f_pos = f->cached_pos; 1234 else { 1235 int i = IP_FW_ARG_TABLEARG(chain, num, skipto); 1236 /* make sure we do not jump backward */ 1237 if (jump_backwards == 0 && i <= f->rulenum) 1238 i = f->rulenum + 1; 1239 if (chain->idxmap != NULL) 1240 f_pos = chain->idxmap[i]; 1241 else 1242 f_pos = ipfw_find_rule(chain, i, 0); 1243 /* update the cache */ 1244 if (num != IP_FW_TARG) { 1245 f->cached_id = chain->id; 1246 f->cached_pos = f_pos; 1247 } 1248 } 1249 1250 return (f_pos); 1251 } 1252 #else 1253 /* 1254 * Helper function to enable real fast rule lookups. 1255 */ 1256 static int 1257 jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num, 1258 int tablearg, int jump_backwards) 1259 { 1260 int f_pos; 1261 1262 num = IP_FW_ARG_TABLEARG(chain, num, skipto); 1263 /* make sure we do not jump backward */ 1264 if (jump_backwards == 0 && num <= f->rulenum) 1265 num = f->rulenum + 1; 1266 f_pos = chain->idxmap[num]; 1267 1268 return (f_pos); 1269 } 1270 #endif 1271 1272 #define TARG(k, f) IP_FW_ARG_TABLEARG(chain, k, f) 1273 /* 1274 * The main check routine for the firewall. 1275 * 1276 * All arguments are in args so we can modify them and return them 1277 * back to the caller. 1278 * 1279 * Parameters: 1280 * 1281 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 1282 * Starts with the IP header. 1283 * args->L3offset Number of bytes bypassed if we came from L2. 1284 * e.g. often sizeof(eh) ** NOTYET ** 1285 * args->ifp Incoming or outgoing interface. 1286 * args->divert_rule (in/out) 1287 * Skip up to the first rule past this rule number; 1288 * upon return, non-zero port number for divert or tee. 1289 * 1290 * args->rule Pointer to the last matching rule (in/out) 1291 * args->next_hop Socket we are forwarding to (out). 1292 * args->next_hop6 IPv6 next hop we are forwarding to (out). 1293 * args->f_id Addresses grabbed from the packet (out) 1294 * args->rule.info a cookie depending on rule action 1295 * 1296 * Return value: 1297 * 1298 * IP_FW_PASS the packet must be accepted 1299 * IP_FW_DENY the packet must be dropped 1300 * IP_FW_DIVERT divert packet, port in m_tag 1301 * IP_FW_TEE tee packet, port in m_tag 1302 * IP_FW_DUMMYNET to dummynet, pipe in args->cookie 1303 * IP_FW_NETGRAPH into netgraph, cookie args->cookie 1304 * args->rule contains the matching rule, 1305 * args->rule.info has additional information. 1306 * 1307 */ 1308 int 1309 ipfw_chk(struct ip_fw_args *args) 1310 { 1311 1312 /* 1313 * Local variables holding state while processing a packet: 1314 * 1315 * IMPORTANT NOTE: to speed up the processing of rules, there 1316 * are some assumption on the values of the variables, which 1317 * are documented here. Should you change them, please check 1318 * the implementation of the various instructions to make sure 1319 * that they still work. 1320 * 1321 * m | args->m Pointer to the mbuf, as received from the caller. 1322 * It may change if ipfw_chk() does an m_pullup, or if it 1323 * consumes the packet because it calls send_reject(). 1324 * XXX This has to change, so that ipfw_chk() never modifies 1325 * or consumes the buffer. 1326 * OR 1327 * args->mem Pointer to contigous memory chunk. 1328 * ip Is the beginning of the ip(4 or 6) header. 1329 * eh Ethernet header in case if input is Layer2. 1330 */ 1331 struct mbuf *m; 1332 struct ip *ip; 1333 struct ether_header *eh; 1334 1335 /* 1336 * For rules which contain uid/gid or jail constraints, cache 1337 * a copy of the users credentials after the pcb lookup has been 1338 * executed. This will speed up the processing of rules with 1339 * these types of constraints, as well as decrease contention 1340 * on pcb related locks. 1341 */ 1342 #ifndef __FreeBSD__ 1343 struct bsd_ucred ucred_cache; 1344 #else 1345 struct ucred *ucred_cache = NULL; 1346 #endif 1347 int ucred_lookup = 0; 1348 int f_pos = 0; /* index of current rule in the array */ 1349 int retval = 0; 1350 struct ifnet *oif, *iif; 1351 1352 /* 1353 * hlen The length of the IP header. 1354 */ 1355 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 1356 1357 /* 1358 * offset The offset of a fragment. offset != 0 means that 1359 * we have a fragment at this offset of an IPv4 packet. 1360 * offset == 0 means that (if this is an IPv4 packet) 1361 * this is the first or only fragment. 1362 * For IPv6 offset|ip6f_mf == 0 means there is no Fragment Header 1363 * or there is a single packet fragment (fragment header added 1364 * without needed). We will treat a single packet fragment as if 1365 * there was no fragment header (or log/block depending on the 1366 * V_fw_permit_single_frag6 sysctl setting). 1367 */ 1368 u_short offset = 0; 1369 u_short ip6f_mf = 0; 1370 1371 /* 1372 * Local copies of addresses. They are only valid if we have 1373 * an IP packet. 1374 * 1375 * proto The protocol. Set to 0 for non-ip packets, 1376 * or to the protocol read from the packet otherwise. 1377 * proto != 0 means that we have an IPv4 packet. 1378 * 1379 * src_port, dst_port port numbers, in HOST format. Only 1380 * valid for TCP and UDP packets. 1381 * 1382 * src_ip, dst_ip ip addresses, in NETWORK format. 1383 * Only valid for IPv4 packets. 1384 */ 1385 uint8_t proto; 1386 uint16_t src_port, dst_port; /* NOTE: host format */ 1387 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 1388 int iplen = 0; 1389 int pktlen; 1390 1391 struct ipfw_dyn_info dyn_info; 1392 struct ip_fw *q = NULL; 1393 struct ip_fw_chain *chain = &V_layer3_chain; 1394 1395 /* 1396 * We store in ulp a pointer to the upper layer protocol header. 1397 * In the ipv4 case this is easy to determine from the header, 1398 * but for ipv6 we might have some additional headers in the middle. 1399 * ulp is NULL if not found. 1400 */ 1401 void *ulp = NULL; /* upper layer protocol pointer. */ 1402 1403 /* XXX ipv6 variables */ 1404 int is_ipv6 = 0; 1405 uint8_t icmp6_type = 0; 1406 uint16_t ext_hd = 0; /* bits vector for extension header filtering */ 1407 /* end of ipv6 variables */ 1408 1409 int is_ipv4 = 0; 1410 1411 int done = 0; /* flag to exit the outer loop */ 1412 IPFW_RLOCK_TRACKER; 1413 bool mem; 1414 1415 if ((mem = (args->flags & IPFW_ARGS_LENMASK))) { 1416 if (args->flags & IPFW_ARGS_ETHER) { 1417 eh = (struct ether_header *)args->mem; 1418 if (eh->ether_type == htons(ETHERTYPE_VLAN)) 1419 ip = (struct ip *) 1420 ((struct ether_vlan_header *)eh + 1); 1421 else 1422 ip = (struct ip *)(eh + 1); 1423 } else { 1424 eh = NULL; 1425 ip = (struct ip *)args->mem; 1426 } 1427 pktlen = IPFW_ARGS_LENGTH(args->flags); 1428 args->f_id.fib = args->ifp->if_fib; /* best guess */ 1429 } else { 1430 m = args->m; 1431 if (m->m_flags & M_SKIP_FIREWALL || (! V_ipfw_vnet_ready)) 1432 return (IP_FW_PASS); /* accept */ 1433 if (args->flags & IPFW_ARGS_ETHER) { 1434 /* We need some amount of data to be contiguous. */ 1435 if (m->m_len < min(m->m_pkthdr.len, max_protohdr) && 1436 (args->m = m = m_pullup(m, min(m->m_pkthdr.len, 1437 max_protohdr))) == NULL) 1438 goto pullup_failed; 1439 eh = mtod(m, struct ether_header *); 1440 ip = (struct ip *)(eh + 1); 1441 } else { 1442 eh = NULL; 1443 ip = mtod(m, struct ip *); 1444 } 1445 pktlen = m->m_pkthdr.len; 1446 args->f_id.fib = M_GETFIB(m); /* mbuf not altered */ 1447 } 1448 1449 dst_ip.s_addr = 0; /* make sure it is initialized */ 1450 src_ip.s_addr = 0; /* make sure it is initialized */ 1451 src_port = dst_port = 0; 1452 1453 DYN_INFO_INIT(&dyn_info); 1454 /* 1455 * PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous, 1456 * then it sets p to point at the offset "len" in the mbuf. WARNING: the 1457 * pointer might become stale after other pullups (but we never use it 1458 * this way). 1459 */ 1460 #define PULLUP_TO(_len, p, T) PULLUP_LEN(_len, p, sizeof(T)) 1461 #define EHLEN (eh != NULL ? ((char *)ip - (char *)eh) : 0) 1462 #define _PULLUP_LOCKED(_len, p, T, unlock) \ 1463 do { \ 1464 int x = (_len) + T + EHLEN; \ 1465 if (mem) { \ 1466 if (__predict_false(pktlen < x)) { \ 1467 unlock; \ 1468 goto pullup_failed; \ 1469 } \ 1470 p = (char *)args->mem + (_len) + EHLEN; \ 1471 } else { \ 1472 if (__predict_false((m)->m_len < x)) { \ 1473 args->m = m = m_pullup(m, x); \ 1474 if (m == NULL) { \ 1475 unlock; \ 1476 goto pullup_failed; \ 1477 } \ 1478 } \ 1479 p = mtod(m, char *) + (_len) + EHLEN; \ 1480 } \ 1481 } while (0) 1482 1483 #define PULLUP_LEN(_len, p, T) _PULLUP_LOCKED(_len, p, T, ) 1484 #define PULLUP_LEN_LOCKED(_len, p, T) \ 1485 _PULLUP_LOCKED(_len, p, T, IPFW_PF_RUNLOCK(chain)); \ 1486 UPDATE_POINTERS() 1487 /* 1488 * In case pointers got stale after pullups, update them. 1489 */ 1490 #define UPDATE_POINTERS() \ 1491 do { \ 1492 if (!mem) { \ 1493 if (eh != NULL) { \ 1494 eh = mtod(m, struct ether_header *); \ 1495 ip = (struct ip *)(eh + 1); \ 1496 } else \ 1497 ip = mtod(m, struct ip *); \ 1498 args->m = m; \ 1499 } \ 1500 } while (0) 1501 1502 /* Identify IP packets and fill up variables. */ 1503 if (pktlen >= sizeof(struct ip6_hdr) && 1504 (eh == NULL || eh->ether_type == htons(ETHERTYPE_IPV6)) && 1505 ip->ip_v == 6) { 1506 struct ip6_hdr *ip6 = (struct ip6_hdr *)ip; 1507 1508 is_ipv6 = 1; 1509 args->flags |= IPFW_ARGS_IP6; 1510 hlen = sizeof(struct ip6_hdr); 1511 proto = ip6->ip6_nxt; 1512 /* Search extension headers to find upper layer protocols */ 1513 while (ulp == NULL && offset == 0) { 1514 switch (proto) { 1515 case IPPROTO_ICMPV6: 1516 PULLUP_TO(hlen, ulp, struct icmp6_hdr); 1517 icmp6_type = ICMP6(ulp)->icmp6_type; 1518 break; 1519 1520 case IPPROTO_TCP: 1521 PULLUP_TO(hlen, ulp, struct tcphdr); 1522 dst_port = TCP(ulp)->th_dport; 1523 src_port = TCP(ulp)->th_sport; 1524 /* save flags for dynamic rules */ 1525 args->f_id._flags = TCP(ulp)->th_flags; 1526 break; 1527 1528 case IPPROTO_SCTP: 1529 if (pktlen >= hlen + sizeof(struct sctphdr) + 1530 sizeof(struct sctp_chunkhdr) + 1531 offsetof(struct sctp_init, a_rwnd)) 1532 PULLUP_LEN(hlen, ulp, 1533 sizeof(struct sctphdr) + 1534 sizeof(struct sctp_chunkhdr) + 1535 offsetof(struct sctp_init, a_rwnd)); 1536 else if (pktlen >= hlen + sizeof(struct sctphdr)) 1537 PULLUP_LEN(hlen, ulp, pktlen - hlen); 1538 else 1539 PULLUP_LEN(hlen, ulp, 1540 sizeof(struct sctphdr)); 1541 src_port = SCTP(ulp)->src_port; 1542 dst_port = SCTP(ulp)->dest_port; 1543 break; 1544 1545 case IPPROTO_UDP: 1546 case IPPROTO_UDPLITE: 1547 PULLUP_TO(hlen, ulp, struct udphdr); 1548 dst_port = UDP(ulp)->uh_dport; 1549 src_port = UDP(ulp)->uh_sport; 1550 break; 1551 1552 case IPPROTO_HOPOPTS: /* RFC 2460 */ 1553 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1554 ext_hd |= EXT_HOPOPTS; 1555 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1556 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1557 ulp = NULL; 1558 break; 1559 1560 case IPPROTO_ROUTING: /* RFC 2460 */ 1561 PULLUP_TO(hlen, ulp, struct ip6_rthdr); 1562 switch (((struct ip6_rthdr *)ulp)->ip6r_type) { 1563 case 0: 1564 ext_hd |= EXT_RTHDR0; 1565 break; 1566 case 2: 1567 ext_hd |= EXT_RTHDR2; 1568 break; 1569 default: 1570 if (V_fw_verbose) 1571 printf("IPFW2: IPV6 - Unknown " 1572 "Routing Header type(%d)\n", 1573 ((struct ip6_rthdr *) 1574 ulp)->ip6r_type); 1575 if (V_fw_deny_unknown_exthdrs) 1576 return (IP_FW_DENY); 1577 break; 1578 } 1579 ext_hd |= EXT_ROUTING; 1580 hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3; 1581 proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt; 1582 ulp = NULL; 1583 break; 1584 1585 case IPPROTO_FRAGMENT: /* RFC 2460 */ 1586 PULLUP_TO(hlen, ulp, struct ip6_frag); 1587 ext_hd |= EXT_FRAGMENT; 1588 hlen += sizeof (struct ip6_frag); 1589 proto = ((struct ip6_frag *)ulp)->ip6f_nxt; 1590 offset = ((struct ip6_frag *)ulp)->ip6f_offlg & 1591 IP6F_OFF_MASK; 1592 ip6f_mf = ((struct ip6_frag *)ulp)->ip6f_offlg & 1593 IP6F_MORE_FRAG; 1594 if (V_fw_permit_single_frag6 == 0 && 1595 offset == 0 && ip6f_mf == 0) { 1596 if (V_fw_verbose) 1597 printf("IPFW2: IPV6 - Invalid " 1598 "Fragment Header\n"); 1599 if (V_fw_deny_unknown_exthdrs) 1600 return (IP_FW_DENY); 1601 break; 1602 } 1603 args->f_id.extra = 1604 ntohl(((struct ip6_frag *)ulp)->ip6f_ident); 1605 ulp = NULL; 1606 break; 1607 1608 case IPPROTO_DSTOPTS: /* RFC 2460 */ 1609 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1610 ext_hd |= EXT_DSTOPTS; 1611 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1612 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1613 ulp = NULL; 1614 break; 1615 1616 case IPPROTO_AH: /* RFC 2402 */ 1617 PULLUP_TO(hlen, ulp, struct ip6_ext); 1618 ext_hd |= EXT_AH; 1619 hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2; 1620 proto = ((struct ip6_ext *)ulp)->ip6e_nxt; 1621 ulp = NULL; 1622 break; 1623 1624 case IPPROTO_ESP: /* RFC 2406 */ 1625 PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */ 1626 /* Anything past Seq# is variable length and 1627 * data past this ext. header is encrypted. */ 1628 ext_hd |= EXT_ESP; 1629 break; 1630 1631 case IPPROTO_NONE: /* RFC 2460 */ 1632 /* 1633 * Packet ends here, and IPv6 header has 1634 * already been pulled up. If ip6e_len!=0 1635 * then octets must be ignored. 1636 */ 1637 ulp = ip; /* non-NULL to get out of loop. */ 1638 break; 1639 1640 case IPPROTO_OSPFIGP: 1641 /* XXX OSPF header check? */ 1642 PULLUP_TO(hlen, ulp, struct ip6_ext); 1643 break; 1644 1645 case IPPROTO_PIM: 1646 /* XXX PIM header check? */ 1647 PULLUP_TO(hlen, ulp, struct pim); 1648 break; 1649 1650 case IPPROTO_GRE: /* RFC 1701 */ 1651 /* XXX GRE header check? */ 1652 PULLUP_TO(hlen, ulp, struct grehdr); 1653 break; 1654 1655 case IPPROTO_CARP: 1656 PULLUP_TO(hlen, ulp, offsetof( 1657 struct carp_header, carp_counter)); 1658 if (CARP_ADVERTISEMENT != 1659 ((struct carp_header *)ulp)->carp_type) 1660 return (IP_FW_DENY); 1661 break; 1662 1663 case IPPROTO_IPV6: /* RFC 2893 */ 1664 PULLUP_TO(hlen, ulp, struct ip6_hdr); 1665 break; 1666 1667 case IPPROTO_IPV4: /* RFC 2893 */ 1668 PULLUP_TO(hlen, ulp, struct ip); 1669 break; 1670 1671 default: 1672 if (V_fw_verbose) 1673 printf("IPFW2: IPV6 - Unknown " 1674 "Extension Header(%d), ext_hd=%x\n", 1675 proto, ext_hd); 1676 if (V_fw_deny_unknown_exthdrs) 1677 return (IP_FW_DENY); 1678 PULLUP_TO(hlen, ulp, struct ip6_ext); 1679 break; 1680 } /*switch */ 1681 } 1682 UPDATE_POINTERS(); 1683 ip6 = (struct ip6_hdr *)ip; 1684 args->f_id.addr_type = 6; 1685 args->f_id.src_ip6 = ip6->ip6_src; 1686 args->f_id.dst_ip6 = ip6->ip6_dst; 1687 args->f_id.flow_id6 = ntohl(ip6->ip6_flow); 1688 iplen = ntohs(ip6->ip6_plen) + sizeof(*ip6); 1689 } else if (pktlen >= sizeof(struct ip) && 1690 (eh == NULL || eh->ether_type == htons(ETHERTYPE_IP)) && 1691 ip->ip_v == 4) { 1692 is_ipv4 = 1; 1693 args->flags |= IPFW_ARGS_IP4; 1694 hlen = ip->ip_hl << 2; 1695 /* 1696 * Collect parameters into local variables for faster 1697 * matching. 1698 */ 1699 proto = ip->ip_p; 1700 src_ip = ip->ip_src; 1701 dst_ip = ip->ip_dst; 1702 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1703 iplen = ntohs(ip->ip_len); 1704 1705 if (offset == 0) { 1706 switch (proto) { 1707 case IPPROTO_TCP: 1708 PULLUP_TO(hlen, ulp, struct tcphdr); 1709 dst_port = TCP(ulp)->th_dport; 1710 src_port = TCP(ulp)->th_sport; 1711 /* save flags for dynamic rules */ 1712 args->f_id._flags = TCP(ulp)->th_flags; 1713 break; 1714 1715 case IPPROTO_SCTP: 1716 if (pktlen >= hlen + sizeof(struct sctphdr) + 1717 sizeof(struct sctp_chunkhdr) + 1718 offsetof(struct sctp_init, a_rwnd)) 1719 PULLUP_LEN(hlen, ulp, 1720 sizeof(struct sctphdr) + 1721 sizeof(struct sctp_chunkhdr) + 1722 offsetof(struct sctp_init, a_rwnd)); 1723 else if (pktlen >= hlen + sizeof(struct sctphdr)) 1724 PULLUP_LEN(hlen, ulp, pktlen - hlen); 1725 else 1726 PULLUP_LEN(hlen, ulp, 1727 sizeof(struct sctphdr)); 1728 src_port = SCTP(ulp)->src_port; 1729 dst_port = SCTP(ulp)->dest_port; 1730 break; 1731 1732 case IPPROTO_UDP: 1733 case IPPROTO_UDPLITE: 1734 PULLUP_TO(hlen, ulp, struct udphdr); 1735 dst_port = UDP(ulp)->uh_dport; 1736 src_port = UDP(ulp)->uh_sport; 1737 break; 1738 1739 case IPPROTO_ICMP: 1740 PULLUP_TO(hlen, ulp, struct icmphdr); 1741 //args->f_id.flags = ICMP(ulp)->icmp_type; 1742 break; 1743 1744 default: 1745 break; 1746 } 1747 } else { 1748 if (offset == 1 && proto == IPPROTO_TCP) { 1749 /* RFC 3128 */ 1750 goto pullup_failed; 1751 } 1752 } 1753 1754 UPDATE_POINTERS(); 1755 args->f_id.addr_type = 4; 1756 args->f_id.src_ip = ntohl(src_ip.s_addr); 1757 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1758 } else { 1759 proto = 0; 1760 dst_ip.s_addr = src_ip.s_addr = 0; 1761 1762 args->f_id.addr_type = 1; /* XXX */ 1763 } 1764 #undef PULLUP_TO 1765 pktlen = iplen < pktlen ? iplen: pktlen; 1766 1767 /* Properly initialize the rest of f_id */ 1768 args->f_id.proto = proto; 1769 args->f_id.src_port = src_port = ntohs(src_port); 1770 args->f_id.dst_port = dst_port = ntohs(dst_port); 1771 1772 IPFW_PF_RLOCK(chain); 1773 if (! V_ipfw_vnet_ready) { /* shutting down, leave NOW. */ 1774 IPFW_PF_RUNLOCK(chain); 1775 return (IP_FW_PASS); /* accept */ 1776 } 1777 if (args->flags & IPFW_ARGS_REF) { 1778 /* 1779 * Packet has already been tagged as a result of a previous 1780 * match on rule args->rule aka args->rule_id (PIPE, QUEUE, 1781 * REASS, NETGRAPH, DIVERT/TEE...) 1782 * Validate the slot and continue from the next one 1783 * if still present, otherwise do a lookup. 1784 */ 1785 f_pos = (args->rule.chain_id == chain->id) ? 1786 args->rule.slot : 1787 ipfw_find_rule(chain, args->rule.rulenum, 1788 args->rule.rule_id); 1789 } else { 1790 f_pos = 0; 1791 } 1792 1793 if (args->flags & IPFW_ARGS_IN) { 1794 iif = args->ifp; 1795 oif = NULL; 1796 } else { 1797 MPASS(args->flags & IPFW_ARGS_OUT); 1798 iif = mem ? NULL : m_rcvif(m); 1799 oif = args->ifp; 1800 } 1801 1802 /* 1803 * Now scan the rules, and parse microinstructions for each rule. 1804 * We have two nested loops and an inner switch. Sometimes we 1805 * need to break out of one or both loops, or re-enter one of 1806 * the loops with updated variables. Loop variables are: 1807 * 1808 * f_pos (outer loop) points to the current rule. 1809 * On output it points to the matching rule. 1810 * done (outer loop) is used as a flag to break the loop. 1811 * l (inner loop) residual length of current rule. 1812 * cmd points to the current microinstruction. 1813 * 1814 * We break the inner loop by setting l=0 and possibly 1815 * cmdlen=0 if we don't want to advance cmd. 1816 * We break the outer loop by setting done=1 1817 * We can restart the inner loop by setting l>0 and f_pos, f, cmd 1818 * as needed. 1819 */ 1820 for (; f_pos < chain->n_rules; f_pos++) { 1821 ipfw_insn *cmd; 1822 uint32_t tablearg = 0; 1823 int l, cmdlen, skip_or; /* skip rest of OR block */ 1824 struct ip_fw *f; 1825 1826 f = chain->map[f_pos]; 1827 if (V_set_disable & (1 << f->set) ) 1828 continue; 1829 1830 skip_or = 0; 1831 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1832 l -= cmdlen, cmd += cmdlen) { 1833 int match; 1834 1835 /* 1836 * check_body is a jump target used when we find a 1837 * CHECK_STATE, and need to jump to the body of 1838 * the target rule. 1839 */ 1840 1841 /* check_body: */ 1842 cmdlen = F_LEN(cmd); 1843 /* 1844 * An OR block (insn_1 || .. || insn_n) has the 1845 * F_OR bit set in all but the last instruction. 1846 * The first match will set "skip_or", and cause 1847 * the following instructions to be skipped until 1848 * past the one with the F_OR bit clear. 1849 */ 1850 if (skip_or) { /* skip this instruction */ 1851 if ((cmd->len & F_OR) == 0) 1852 skip_or = 0; /* next one is good */ 1853 continue; 1854 } 1855 match = 0; /* set to 1 if we succeed */ 1856 1857 switch (cmd->opcode) { 1858 /* 1859 * The first set of opcodes compares the packet's 1860 * fields with some pattern, setting 'match' if a 1861 * match is found. At the end of the loop there is 1862 * logic to deal with F_NOT and F_OR flags associated 1863 * with the opcode. 1864 */ 1865 case O_NOP: 1866 match = 1; 1867 break; 1868 1869 case O_FORWARD_MAC: 1870 printf("ipfw: opcode %d unimplemented\n", 1871 cmd->opcode); 1872 break; 1873 1874 case O_GID: 1875 case O_UID: 1876 case O_JAIL: 1877 /* 1878 * We only check offset == 0 && proto != 0, 1879 * as this ensures that we have a 1880 * packet with the ports info. 1881 */ 1882 if (offset != 0) 1883 break; 1884 if (proto == IPPROTO_TCP || 1885 proto == IPPROTO_UDP || 1886 proto == IPPROTO_UDPLITE) 1887 match = check_uidgid( 1888 (ipfw_insn_u32 *)cmd, 1889 args, &ucred_lookup, 1890 #ifdef __FreeBSD__ 1891 &ucred_cache); 1892 #else 1893 (void *)&ucred_cache); 1894 #endif 1895 break; 1896 1897 case O_RECV: 1898 match = iface_match(iif, (ipfw_insn_if *)cmd, 1899 chain, &tablearg); 1900 break; 1901 1902 case O_XMIT: 1903 match = iface_match(oif, (ipfw_insn_if *)cmd, 1904 chain, &tablearg); 1905 break; 1906 1907 case O_VIA: 1908 match = iface_match(args->ifp, 1909 (ipfw_insn_if *)cmd, chain, &tablearg); 1910 break; 1911 1912 case O_MACADDR2: 1913 if (args->flags & IPFW_ARGS_ETHER) { 1914 u_int32_t *want = (u_int32_t *) 1915 ((ipfw_insn_mac *)cmd)->addr; 1916 u_int32_t *mask = (u_int32_t *) 1917 ((ipfw_insn_mac *)cmd)->mask; 1918 u_int32_t *hdr = (u_int32_t *)eh; 1919 1920 match = 1921 ( want[0] == (hdr[0] & mask[0]) && 1922 want[1] == (hdr[1] & mask[1]) && 1923 want[2] == (hdr[2] & mask[2]) ); 1924 } 1925 break; 1926 1927 case O_MAC_TYPE: 1928 if (args->flags & IPFW_ARGS_ETHER) { 1929 u_int16_t *p = 1930 ((ipfw_insn_u16 *)cmd)->ports; 1931 int i; 1932 1933 for (i = cmdlen - 1; !match && i>0; 1934 i--, p += 2) 1935 match = 1936 (ntohs(eh->ether_type) >= 1937 p[0] && 1938 ntohs(eh->ether_type) <= 1939 p[1]); 1940 } 1941 break; 1942 1943 case O_FRAG: 1944 match = (offset != 0); 1945 break; 1946 1947 case O_IN: /* "out" is "not in" */ 1948 match = (oif == NULL); 1949 break; 1950 1951 case O_LAYER2: 1952 match = (args->flags & IPFW_ARGS_ETHER); 1953 break; 1954 1955 case O_DIVERTED: 1956 if ((args->flags & IPFW_ARGS_REF) == 0) 1957 break; 1958 /* 1959 * For diverted packets, args->rule.info 1960 * contains the divert port (in host format) 1961 * reason and direction. 1962 */ 1963 match = ((args->rule.info & IPFW_IS_MASK) == 1964 IPFW_IS_DIVERT) && ( 1965 ((args->rule.info & IPFW_INFO_IN) ? 1966 1: 2) & cmd->arg1); 1967 break; 1968 1969 case O_PROTO: 1970 /* 1971 * We do not allow an arg of 0 so the 1972 * check of "proto" only suffices. 1973 */ 1974 match = (proto == cmd->arg1); 1975 break; 1976 1977 case O_IP_SRC: 1978 match = is_ipv4 && 1979 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1980 src_ip.s_addr); 1981 break; 1982 1983 case O_IP_DST_LOOKUP: 1984 { 1985 void *pkey; 1986 uint32_t vidx, key; 1987 uint16_t keylen; 1988 1989 if (cmdlen > F_INSN_SIZE(ipfw_insn_u32)) { 1990 /* Determine lookup key type */ 1991 vidx = ((ipfw_insn_u32 *)cmd)->d[1]; 1992 if (vidx != 4 /* uid */ && 1993 vidx != 5 /* jail */ && 1994 is_ipv6 == 0 && is_ipv4 == 0) 1995 break; 1996 /* Determine key length */ 1997 if (vidx == 0 /* dst-ip */ || 1998 vidx == 1 /* src-ip */) 1999 keylen = is_ipv6 ? 2000 sizeof(struct in6_addr): 2001 sizeof(in_addr_t); 2002 else { 2003 keylen = sizeof(key); 2004 pkey = &key; 2005 } 2006 if (vidx == 0 /* dst-ip */) 2007 pkey = is_ipv4 ? (void *)&dst_ip: 2008 (void *)&args->f_id.dst_ip6; 2009 else if (vidx == 1 /* src-ip */) 2010 pkey = is_ipv4 ? (void *)&src_ip: 2011 (void *)&args->f_id.src_ip6; 2012 else if (vidx == 6 /* dscp */) { 2013 if (is_ipv4) 2014 key = ip->ip_tos >> 2; 2015 else { 2016 key = args->f_id.flow_id6; 2017 key = (key & 0x0f) << 2 | 2018 (key & 0xf000) >> 14; 2019 } 2020 key &= 0x3f; 2021 } else if (vidx == 2 /* dst-port */ || 2022 vidx == 3 /* src-port */) { 2023 /* Skip fragments */ 2024 if (offset != 0) 2025 break; 2026 /* Skip proto without ports */ 2027 if (proto != IPPROTO_TCP && 2028 proto != IPPROTO_UDP && 2029 proto != IPPROTO_UDPLITE && 2030 proto != IPPROTO_SCTP) 2031 break; 2032 if (vidx == 2 /* dst-port */) 2033 key = dst_port; 2034 else 2035 key = src_port; 2036 } 2037 #ifndef USERSPACE 2038 else if (vidx == 4 /* uid */ || 2039 vidx == 5 /* jail */) { 2040 check_uidgid( 2041 (ipfw_insn_u32 *)cmd, 2042 args, &ucred_lookup, 2043 #ifdef __FreeBSD__ 2044 &ucred_cache); 2045 if (vidx == 4 /* uid */) 2046 key = ucred_cache->cr_uid; 2047 else if (vidx == 5 /* jail */) 2048 key = ucred_cache->cr_prison->pr_id; 2049 #else /* !__FreeBSD__ */ 2050 (void *)&ucred_cache); 2051 if (vidx == 4 /* uid */) 2052 key = ucred_cache.uid; 2053 else if (vidx == 5 /* jail */) 2054 key = ucred_cache.xid; 2055 #endif /* !__FreeBSD__ */ 2056 } 2057 #endif /* !USERSPACE */ 2058 else 2059 break; 2060 match = ipfw_lookup_table(chain, 2061 cmd->arg1, keylen, pkey, &vidx); 2062 if (!match) 2063 break; 2064 tablearg = vidx; 2065 break; 2066 } 2067 /* cmdlen =< F_INSN_SIZE(ipfw_insn_u32) */ 2068 /* FALLTHROUGH */ 2069 } 2070 case O_IP_SRC_LOOKUP: 2071 { 2072 void *pkey; 2073 uint32_t vidx; 2074 uint16_t keylen; 2075 2076 if (is_ipv4) { 2077 keylen = sizeof(in_addr_t); 2078 if (cmd->opcode == O_IP_DST_LOOKUP) 2079 pkey = &dst_ip; 2080 else 2081 pkey = &src_ip; 2082 } else if (is_ipv6) { 2083 keylen = sizeof(struct in6_addr); 2084 if (cmd->opcode == O_IP_DST_LOOKUP) 2085 pkey = &args->f_id.dst_ip6; 2086 else 2087 pkey = &args->f_id.src_ip6; 2088 } else 2089 break; 2090 match = ipfw_lookup_table(chain, cmd->arg1, 2091 keylen, pkey, &vidx); 2092 if (!match) 2093 break; 2094 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) { 2095 match = ((ipfw_insn_u32 *)cmd)->d[0] == 2096 TARG_VAL(chain, vidx, tag); 2097 if (!match) 2098 break; 2099 } 2100 tablearg = vidx; 2101 break; 2102 } 2103 2104 case O_IP_FLOW_LOOKUP: 2105 { 2106 uint32_t v = 0; 2107 match = ipfw_lookup_table(chain, 2108 cmd->arg1, 0, &args->f_id, &v); 2109 if (!match) 2110 break; 2111 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 2112 match = ((ipfw_insn_u32 *)cmd)->d[0] == 2113 TARG_VAL(chain, v, tag); 2114 if (match) 2115 tablearg = v; 2116 } 2117 break; 2118 case O_IP_SRC_MASK: 2119 case O_IP_DST_MASK: 2120 if (is_ipv4) { 2121 uint32_t a = 2122 (cmd->opcode == O_IP_DST_MASK) ? 2123 dst_ip.s_addr : src_ip.s_addr; 2124 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 2125 int i = cmdlen-1; 2126 2127 for (; !match && i>0; i-= 2, p+= 2) 2128 match = (p[0] == (a & p[1])); 2129 } 2130 break; 2131 2132 case O_IP_SRC_ME: 2133 if (is_ipv4) { 2134 match = in_localip(src_ip); 2135 break; 2136 } 2137 #ifdef INET6 2138 /* FALLTHROUGH */ 2139 case O_IP6_SRC_ME: 2140 match = is_ipv6 && 2141 ipfw_localip6(&args->f_id.src_ip6); 2142 #endif 2143 break; 2144 2145 case O_IP_DST_SET: 2146 case O_IP_SRC_SET: 2147 if (is_ipv4) { 2148 u_int32_t *d = (u_int32_t *)(cmd+1); 2149 u_int32_t addr = 2150 cmd->opcode == O_IP_DST_SET ? 2151 args->f_id.dst_ip : 2152 args->f_id.src_ip; 2153 2154 if (addr < d[0]) 2155 break; 2156 addr -= d[0]; /* subtract base */ 2157 match = (addr < cmd->arg1) && 2158 ( d[ 1 + (addr>>5)] & 2159 (1<<(addr & 0x1f)) ); 2160 } 2161 break; 2162 2163 case O_IP_DST: 2164 match = is_ipv4 && 2165 (((ipfw_insn_ip *)cmd)->addr.s_addr == 2166 dst_ip.s_addr); 2167 break; 2168 2169 case O_IP_DST_ME: 2170 if (is_ipv4) { 2171 match = in_localip(dst_ip); 2172 break; 2173 } 2174 #ifdef INET6 2175 /* FALLTHROUGH */ 2176 case O_IP6_DST_ME: 2177 match = is_ipv6 && 2178 ipfw_localip6(&args->f_id.dst_ip6); 2179 #endif 2180 break; 2181 2182 2183 case O_IP_SRCPORT: 2184 case O_IP_DSTPORT: 2185 /* 2186 * offset == 0 && proto != 0 is enough 2187 * to guarantee that we have a 2188 * packet with port info. 2189 */ 2190 if ((proto == IPPROTO_UDP || 2191 proto == IPPROTO_UDPLITE || 2192 proto == IPPROTO_TCP || 2193 proto == IPPROTO_SCTP) && offset == 0) { 2194 u_int16_t x = 2195 (cmd->opcode == O_IP_SRCPORT) ? 2196 src_port : dst_port ; 2197 u_int16_t *p = 2198 ((ipfw_insn_u16 *)cmd)->ports; 2199 int i; 2200 2201 for (i = cmdlen - 1; !match && i>0; 2202 i--, p += 2) 2203 match = (x>=p[0] && x<=p[1]); 2204 } 2205 break; 2206 2207 case O_ICMPTYPE: 2208 match = (offset == 0 && proto==IPPROTO_ICMP && 2209 icmptype_match(ICMP(ulp), (ipfw_insn_u32 *)cmd) ); 2210 break; 2211 2212 #ifdef INET6 2213 case O_ICMP6TYPE: 2214 match = is_ipv6 && offset == 0 && 2215 proto==IPPROTO_ICMPV6 && 2216 icmp6type_match( 2217 ICMP6(ulp)->icmp6_type, 2218 (ipfw_insn_u32 *)cmd); 2219 break; 2220 #endif /* INET6 */ 2221 2222 case O_IPOPT: 2223 match = (is_ipv4 && 2224 ipopts_match(ip, cmd) ); 2225 break; 2226 2227 case O_IPVER: 2228 match = (is_ipv4 && 2229 cmd->arg1 == ip->ip_v); 2230 break; 2231 2232 case O_IPID: 2233 case O_IPTTL: 2234 if (!is_ipv4) 2235 break; 2236 case O_IPLEN: 2237 { /* only for IP packets */ 2238 uint16_t x; 2239 uint16_t *p; 2240 int i; 2241 2242 if (cmd->opcode == O_IPLEN) 2243 x = iplen; 2244 else if (cmd->opcode == O_IPTTL) 2245 x = ip->ip_ttl; 2246 else /* must be IPID */ 2247 x = ntohs(ip->ip_id); 2248 if (cmdlen == 1) { 2249 match = (cmd->arg1 == x); 2250 break; 2251 } 2252 /* otherwise we have ranges */ 2253 p = ((ipfw_insn_u16 *)cmd)->ports; 2254 i = cmdlen - 1; 2255 for (; !match && i>0; i--, p += 2) 2256 match = (x >= p[0] && x <= p[1]); 2257 } 2258 break; 2259 2260 case O_IPPRECEDENCE: 2261 match = (is_ipv4 && 2262 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 2263 break; 2264 2265 case O_IPTOS: 2266 match = (is_ipv4 && 2267 flags_match(cmd, ip->ip_tos)); 2268 break; 2269 2270 case O_DSCP: 2271 { 2272 uint32_t *p; 2273 uint16_t x; 2274 2275 p = ((ipfw_insn_u32 *)cmd)->d; 2276 2277 if (is_ipv4) 2278 x = ip->ip_tos >> 2; 2279 else if (is_ipv6) { 2280 uint8_t *v; 2281 v = &((struct ip6_hdr *)ip)->ip6_vfc; 2282 x = (*v & 0x0F) << 2; 2283 v++; 2284 x |= *v >> 6; 2285 } else 2286 break; 2287 2288 /* DSCP bitmask is stored as low_u32 high_u32 */ 2289 if (x >= 32) 2290 match = *(p + 1) & (1 << (x - 32)); 2291 else 2292 match = *p & (1 << x); 2293 } 2294 break; 2295 2296 case O_TCPDATALEN: 2297 if (proto == IPPROTO_TCP && offset == 0) { 2298 struct tcphdr *tcp; 2299 uint16_t x; 2300 uint16_t *p; 2301 int i; 2302 #ifdef INET6 2303 if (is_ipv6) { 2304 struct ip6_hdr *ip6; 2305 2306 ip6 = (struct ip6_hdr *)ip; 2307 if (ip6->ip6_plen == 0) { 2308 /* 2309 * Jumbo payload is not 2310 * supported by this 2311 * opcode. 2312 */ 2313 break; 2314 } 2315 x = iplen - hlen; 2316 } else 2317 #endif /* INET6 */ 2318 x = iplen - (ip->ip_hl << 2); 2319 tcp = TCP(ulp); 2320 x -= tcp->th_off << 2; 2321 if (cmdlen == 1) { 2322 match = (cmd->arg1 == x); 2323 break; 2324 } 2325 /* otherwise we have ranges */ 2326 p = ((ipfw_insn_u16 *)cmd)->ports; 2327 i = cmdlen - 1; 2328 for (; !match && i>0; i--, p += 2) 2329 match = (x >= p[0] && x <= p[1]); 2330 } 2331 break; 2332 2333 case O_TCPFLAGS: 2334 match = (proto == IPPROTO_TCP && offset == 0 && 2335 flags_match(cmd, TCP(ulp)->th_flags)); 2336 break; 2337 2338 case O_TCPOPTS: 2339 if (proto == IPPROTO_TCP && offset == 0 && ulp){ 2340 PULLUP_LEN_LOCKED(hlen, ulp, 2341 (TCP(ulp)->th_off << 2)); 2342 match = tcpopts_match(TCP(ulp), cmd); 2343 } 2344 break; 2345 2346 case O_TCPSEQ: 2347 match = (proto == IPPROTO_TCP && offset == 0 && 2348 ((ipfw_insn_u32 *)cmd)->d[0] == 2349 TCP(ulp)->th_seq); 2350 break; 2351 2352 case O_TCPACK: 2353 match = (proto == IPPROTO_TCP && offset == 0 && 2354 ((ipfw_insn_u32 *)cmd)->d[0] == 2355 TCP(ulp)->th_ack); 2356 break; 2357 2358 case O_TCPMSS: 2359 if (proto == IPPROTO_TCP && 2360 (args->f_id._flags & TH_SYN) != 0 && 2361 ulp != NULL) { 2362 uint16_t mss, *p; 2363 int i; 2364 2365 PULLUP_LEN_LOCKED(hlen, ulp, 2366 (TCP(ulp)->th_off << 2)); 2367 if ((tcpopts_parse(TCP(ulp), &mss) & 2368 IP_FW_TCPOPT_MSS) == 0) 2369 break; 2370 if (cmdlen == 1) { 2371 match = (cmd->arg1 == mss); 2372 break; 2373 } 2374 /* Otherwise we have ranges. */ 2375 p = ((ipfw_insn_u16 *)cmd)->ports; 2376 i = cmdlen - 1; 2377 for (; !match && i > 0; i--, p += 2) 2378 match = (mss >= p[0] && 2379 mss <= p[1]); 2380 } 2381 break; 2382 2383 case O_TCPWIN: 2384 if (proto == IPPROTO_TCP && offset == 0) { 2385 uint16_t x; 2386 uint16_t *p; 2387 int i; 2388 2389 x = ntohs(TCP(ulp)->th_win); 2390 if (cmdlen == 1) { 2391 match = (cmd->arg1 == x); 2392 break; 2393 } 2394 /* Otherwise we have ranges. */ 2395 p = ((ipfw_insn_u16 *)cmd)->ports; 2396 i = cmdlen - 1; 2397 for (; !match && i > 0; i--, p += 2) 2398 match = (x >= p[0] && x <= p[1]); 2399 } 2400 break; 2401 2402 case O_ESTAB: 2403 /* reject packets which have SYN only */ 2404 /* XXX should i also check for TH_ACK ? */ 2405 match = (proto == IPPROTO_TCP && offset == 0 && 2406 (TCP(ulp)->th_flags & 2407 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 2408 break; 2409 2410 case O_ALTQ: { 2411 struct pf_mtag *at; 2412 struct m_tag *mtag; 2413 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 2414 2415 /* 2416 * ALTQ uses mbuf tags from another 2417 * packet filtering system - pf(4). 2418 * We allocate a tag in its format 2419 * and fill it in, pretending to be pf(4). 2420 */ 2421 match = 1; 2422 at = pf_find_mtag(m); 2423 if (at != NULL && at->qid != 0) 2424 break; 2425 mtag = m_tag_get(PACKET_TAG_PF, 2426 sizeof(struct pf_mtag), M_NOWAIT | M_ZERO); 2427 if (mtag == NULL) { 2428 /* 2429 * Let the packet fall back to the 2430 * default ALTQ. 2431 */ 2432 break; 2433 } 2434 m_tag_prepend(m, mtag); 2435 at = (struct pf_mtag *)(mtag + 1); 2436 at->qid = altq->qid; 2437 at->hdr = ip; 2438 break; 2439 } 2440 2441 case O_LOG: 2442 ipfw_log(chain, f, hlen, args, 2443 offset | ip6f_mf, tablearg, ip); 2444 match = 1; 2445 break; 2446 2447 case O_PROB: 2448 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 2449 break; 2450 2451 case O_VERREVPATH: 2452 /* Outgoing packets automatically pass/match */ 2453 match = (args->flags & IPFW_ARGS_OUT || 2454 ( 2455 #ifdef INET6 2456 is_ipv6 ? 2457 verify_path6(&(args->f_id.src_ip6), 2458 iif, args->f_id.fib) : 2459 #endif 2460 verify_path(src_ip, iif, args->f_id.fib))); 2461 break; 2462 2463 case O_VERSRCREACH: 2464 /* Outgoing packets automatically pass/match */ 2465 match = (hlen > 0 && ((oif != NULL) || ( 2466 #ifdef INET6 2467 is_ipv6 ? 2468 verify_path6(&(args->f_id.src_ip6), 2469 NULL, args->f_id.fib) : 2470 #endif 2471 verify_path(src_ip, NULL, args->f_id.fib)))); 2472 break; 2473 2474 case O_ANTISPOOF: 2475 /* Outgoing packets automatically pass/match */ 2476 if (oif == NULL && hlen > 0 && 2477 ( (is_ipv4 && in_localaddr(src_ip)) 2478 #ifdef INET6 2479 || (is_ipv6 && 2480 in6_localaddr(&(args->f_id.src_ip6))) 2481 #endif 2482 )) 2483 match = 2484 #ifdef INET6 2485 is_ipv6 ? verify_path6( 2486 &(args->f_id.src_ip6), iif, 2487 args->f_id.fib) : 2488 #endif 2489 verify_path(src_ip, iif, 2490 args->f_id.fib); 2491 else 2492 match = 1; 2493 break; 2494 2495 case O_IPSEC: 2496 match = (m_tag_find(m, 2497 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 2498 /* otherwise no match */ 2499 break; 2500 2501 #ifdef INET6 2502 case O_IP6_SRC: 2503 match = is_ipv6 && 2504 IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6, 2505 &((ipfw_insn_ip6 *)cmd)->addr6); 2506 break; 2507 2508 case O_IP6_DST: 2509 match = is_ipv6 && 2510 IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6, 2511 &((ipfw_insn_ip6 *)cmd)->addr6); 2512 break; 2513 case O_IP6_SRC_MASK: 2514 case O_IP6_DST_MASK: 2515 if (is_ipv6) { 2516 int i = cmdlen - 1; 2517 struct in6_addr p; 2518 struct in6_addr *d = 2519 &((ipfw_insn_ip6 *)cmd)->addr6; 2520 2521 for (; !match && i > 0; d += 2, 2522 i -= F_INSN_SIZE(struct in6_addr) 2523 * 2) { 2524 p = (cmd->opcode == 2525 O_IP6_SRC_MASK) ? 2526 args->f_id.src_ip6: 2527 args->f_id.dst_ip6; 2528 APPLY_MASK(&p, &d[1]); 2529 match = 2530 IN6_ARE_ADDR_EQUAL(&d[0], 2531 &p); 2532 } 2533 } 2534 break; 2535 2536 case O_FLOW6ID: 2537 match = is_ipv6 && 2538 flow6id_match(args->f_id.flow_id6, 2539 (ipfw_insn_u32 *) cmd); 2540 break; 2541 2542 case O_EXT_HDR: 2543 match = is_ipv6 && 2544 (ext_hd & ((ipfw_insn *) cmd)->arg1); 2545 break; 2546 2547 case O_IP6: 2548 match = is_ipv6; 2549 break; 2550 #endif 2551 2552 case O_IP4: 2553 match = is_ipv4; 2554 break; 2555 2556 case O_TAG: { 2557 struct m_tag *mtag; 2558 uint32_t tag = TARG(cmd->arg1, tag); 2559 2560 /* Packet is already tagged with this tag? */ 2561 mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL); 2562 2563 /* We have `untag' action when F_NOT flag is 2564 * present. And we must remove this mtag from 2565 * mbuf and reset `match' to zero (`match' will 2566 * be inversed later). 2567 * Otherwise we should allocate new mtag and 2568 * push it into mbuf. 2569 */ 2570 if (cmd->len & F_NOT) { /* `untag' action */ 2571 if (mtag != NULL) 2572 m_tag_delete(m, mtag); 2573 match = 0; 2574 } else { 2575 if (mtag == NULL) { 2576 mtag = m_tag_alloc( MTAG_IPFW, 2577 tag, 0, M_NOWAIT); 2578 if (mtag != NULL) 2579 m_tag_prepend(m, mtag); 2580 } 2581 match = 1; 2582 } 2583 break; 2584 } 2585 2586 case O_FIB: /* try match the specified fib */ 2587 if (args->f_id.fib == cmd->arg1) 2588 match = 1; 2589 break; 2590 2591 case O_SOCKARG: { 2592 #ifndef USERSPACE /* not supported in userspace */ 2593 struct inpcb *inp = args->inp; 2594 struct inpcbinfo *pi; 2595 2596 if (is_ipv6) /* XXX can we remove this ? */ 2597 break; 2598 2599 if (proto == IPPROTO_TCP) 2600 pi = &V_tcbinfo; 2601 else if (proto == IPPROTO_UDP) 2602 pi = &V_udbinfo; 2603 else if (proto == IPPROTO_UDPLITE) 2604 pi = &V_ulitecbinfo; 2605 else 2606 break; 2607 2608 /* 2609 * XXXRW: so_user_cookie should almost 2610 * certainly be inp_user_cookie? 2611 */ 2612 2613 /* For incoming packet, lookup up the 2614 inpcb using the src/dest ip/port tuple */ 2615 if (inp == NULL) { 2616 inp = in_pcblookup(pi, 2617 src_ip, htons(src_port), 2618 dst_ip, htons(dst_port), 2619 INPLOOKUP_RLOCKPCB, NULL); 2620 if (inp != NULL) { 2621 tablearg = 2622 inp->inp_socket->so_user_cookie; 2623 if (tablearg) 2624 match = 1; 2625 INP_RUNLOCK(inp); 2626 } 2627 } else { 2628 if (inp->inp_socket) { 2629 tablearg = 2630 inp->inp_socket->so_user_cookie; 2631 if (tablearg) 2632 match = 1; 2633 } 2634 } 2635 #endif /* !USERSPACE */ 2636 break; 2637 } 2638 2639 case O_TAGGED: { 2640 struct m_tag *mtag; 2641 uint32_t tag = TARG(cmd->arg1, tag); 2642 2643 if (cmdlen == 1) { 2644 match = m_tag_locate(m, MTAG_IPFW, 2645 tag, NULL) != NULL; 2646 break; 2647 } 2648 2649 /* we have ranges */ 2650 for (mtag = m_tag_first(m); 2651 mtag != NULL && !match; 2652 mtag = m_tag_next(m, mtag)) { 2653 uint16_t *p; 2654 int i; 2655 2656 if (mtag->m_tag_cookie != MTAG_IPFW) 2657 continue; 2658 2659 p = ((ipfw_insn_u16 *)cmd)->ports; 2660 i = cmdlen - 1; 2661 for(; !match && i > 0; i--, p += 2) 2662 match = 2663 mtag->m_tag_id >= p[0] && 2664 mtag->m_tag_id <= p[1]; 2665 } 2666 break; 2667 } 2668 2669 /* 2670 * The second set of opcodes represents 'actions', 2671 * i.e. the terminal part of a rule once the packet 2672 * matches all previous patterns. 2673 * Typically there is only one action for each rule, 2674 * and the opcode is stored at the end of the rule 2675 * (but there are exceptions -- see below). 2676 * 2677 * In general, here we set retval and terminate the 2678 * outer loop (would be a 'break 3' in some language, 2679 * but we need to set l=0, done=1) 2680 * 2681 * Exceptions: 2682 * O_COUNT and O_SKIPTO actions: 2683 * instead of terminating, we jump to the next rule 2684 * (setting l=0), or to the SKIPTO target (setting 2685 * f/f_len, cmd and l as needed), respectively. 2686 * 2687 * O_TAG, O_LOG and O_ALTQ action parameters: 2688 * perform some action and set match = 1; 2689 * 2690 * O_LIMIT and O_KEEP_STATE: these opcodes are 2691 * not real 'actions', and are stored right 2692 * before the 'action' part of the rule (one 2693 * exception is O_SKIP_ACTION which could be 2694 * between these opcodes and 'action' one). 2695 * These opcodes try to install an entry in the 2696 * state tables; if successful, we continue with 2697 * the next opcode (match=1; break;), otherwise 2698 * the packet must be dropped (set retval, 2699 * break loops with l=0, done=1) 2700 * 2701 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 2702 * cause a lookup of the state table, and a jump 2703 * to the 'action' part of the parent rule 2704 * if an entry is found, or 2705 * (CHECK_STATE only) a jump to the next rule if 2706 * the entry is not found. 2707 * The result of the lookup is cached so that 2708 * further instances of these opcodes become NOPs. 2709 * The jump to the next rule is done by setting 2710 * l=0, cmdlen=0. 2711 * 2712 * O_SKIP_ACTION: this opcode is not a real 'action' 2713 * either, and is stored right before the 'action' 2714 * part of the rule, right after the O_KEEP_STATE 2715 * opcode. It causes match failure so the real 2716 * 'action' could be executed only if the rule 2717 * is checked via dynamic rule from the state 2718 * table, as in such case execution starts 2719 * from the true 'action' opcode directly. 2720 * 2721 */ 2722 case O_LIMIT: 2723 case O_KEEP_STATE: 2724 if (ipfw_dyn_install_state(chain, f, 2725 (ipfw_insn_limit *)cmd, args, ulp, 2726 pktlen, &dyn_info, tablearg)) { 2727 /* error or limit violation */ 2728 retval = IP_FW_DENY; 2729 l = 0; /* exit inner loop */ 2730 done = 1; /* exit outer loop */ 2731 } 2732 match = 1; 2733 break; 2734 2735 case O_PROBE_STATE: 2736 case O_CHECK_STATE: 2737 /* 2738 * dynamic rules are checked at the first 2739 * keep-state or check-state occurrence, 2740 * with the result being stored in dyn_info. 2741 * The compiler introduces a PROBE_STATE 2742 * instruction for us when we have a 2743 * KEEP_STATE (because PROBE_STATE needs 2744 * to be run first). 2745 */ 2746 if (DYN_LOOKUP_NEEDED(&dyn_info, cmd) && 2747 (q = ipfw_dyn_lookup_state(args, ulp, 2748 pktlen, cmd, &dyn_info)) != NULL) { 2749 /* 2750 * Found dynamic entry, jump to the 2751 * 'action' part of the parent rule 2752 * by setting f, cmd, l and clearing 2753 * cmdlen. 2754 */ 2755 f = q; 2756 f_pos = dyn_info.f_pos; 2757 cmd = ACTION_PTR(f); 2758 l = f->cmd_len - f->act_ofs; 2759 cmdlen = 0; 2760 match = 1; 2761 break; 2762 } 2763 /* 2764 * Dynamic entry not found. If CHECK_STATE, 2765 * skip to next rule, if PROBE_STATE just 2766 * ignore and continue with next opcode. 2767 */ 2768 if (cmd->opcode == O_CHECK_STATE) 2769 l = 0; /* exit inner loop */ 2770 match = 1; 2771 break; 2772 2773 case O_SKIP_ACTION: 2774 match = 0; /* skip to the next rule */ 2775 l = 0; /* exit inner loop */ 2776 break; 2777 2778 case O_ACCEPT: 2779 retval = 0; /* accept */ 2780 l = 0; /* exit inner loop */ 2781 done = 1; /* exit outer loop */ 2782 break; 2783 2784 case O_PIPE: 2785 case O_QUEUE: 2786 set_match(args, f_pos, chain); 2787 args->rule.info = TARG(cmd->arg1, pipe); 2788 if (cmd->opcode == O_PIPE) 2789 args->rule.info |= IPFW_IS_PIPE; 2790 if (V_fw_one_pass) 2791 args->rule.info |= IPFW_ONEPASS; 2792 retval = IP_FW_DUMMYNET; 2793 l = 0; /* exit inner loop */ 2794 done = 1; /* exit outer loop */ 2795 break; 2796 2797 case O_DIVERT: 2798 case O_TEE: 2799 if (args->flags & IPFW_ARGS_ETHER) 2800 break; /* not on layer 2 */ 2801 /* otherwise this is terminal */ 2802 l = 0; /* exit inner loop */ 2803 done = 1; /* exit outer loop */ 2804 retval = (cmd->opcode == O_DIVERT) ? 2805 IP_FW_DIVERT : IP_FW_TEE; 2806 set_match(args, f_pos, chain); 2807 args->rule.info = TARG(cmd->arg1, divert); 2808 break; 2809 2810 case O_COUNT: 2811 IPFW_INC_RULE_COUNTER(f, pktlen); 2812 l = 0; /* exit inner loop */ 2813 break; 2814 2815 case O_SKIPTO: 2816 IPFW_INC_RULE_COUNTER(f, pktlen); 2817 f_pos = JUMP(chain, f, cmd->arg1, tablearg, 0); 2818 /* 2819 * Skip disabled rules, and re-enter 2820 * the inner loop with the correct 2821 * f_pos, f, l and cmd. 2822 * Also clear cmdlen and skip_or 2823 */ 2824 for (; f_pos < chain->n_rules - 1 && 2825 (V_set_disable & 2826 (1 << chain->map[f_pos]->set)); 2827 f_pos++) 2828 ; 2829 /* Re-enter the inner loop at the skipto rule. */ 2830 f = chain->map[f_pos]; 2831 l = f->cmd_len; 2832 cmd = f->cmd; 2833 match = 1; 2834 cmdlen = 0; 2835 skip_or = 0; 2836 continue; 2837 break; /* not reached */ 2838 2839 case O_CALLRETURN: { 2840 /* 2841 * Implementation of `subroutine' call/return, 2842 * in the stack carried in an mbuf tag. This 2843 * is different from `skipto' in that any call 2844 * address is possible (`skipto' must prevent 2845 * backward jumps to avoid endless loops). 2846 * We have `return' action when F_NOT flag is 2847 * present. The `m_tag_id' field is used as 2848 * stack pointer. 2849 */ 2850 struct m_tag *mtag; 2851 uint16_t jmpto, *stack; 2852 2853 #define IS_CALL ((cmd->len & F_NOT) == 0) 2854 #define IS_RETURN ((cmd->len & F_NOT) != 0) 2855 /* 2856 * Hand-rolled version of m_tag_locate() with 2857 * wildcard `type'. 2858 * If not already tagged, allocate new tag. 2859 */ 2860 mtag = m_tag_first(m); 2861 while (mtag != NULL) { 2862 if (mtag->m_tag_cookie == 2863 MTAG_IPFW_CALL) 2864 break; 2865 mtag = m_tag_next(m, mtag); 2866 } 2867 if (mtag == NULL && IS_CALL) { 2868 mtag = m_tag_alloc(MTAG_IPFW_CALL, 0, 2869 IPFW_CALLSTACK_SIZE * 2870 sizeof(uint16_t), M_NOWAIT); 2871 if (mtag != NULL) 2872 m_tag_prepend(m, mtag); 2873 } 2874 2875 /* 2876 * On error both `call' and `return' just 2877 * continue with next rule. 2878 */ 2879 if (IS_RETURN && (mtag == NULL || 2880 mtag->m_tag_id == 0)) { 2881 l = 0; /* exit inner loop */ 2882 break; 2883 } 2884 if (IS_CALL && (mtag == NULL || 2885 mtag->m_tag_id >= IPFW_CALLSTACK_SIZE)) { 2886 printf("ipfw: call stack error, " 2887 "go to next rule\n"); 2888 l = 0; /* exit inner loop */ 2889 break; 2890 } 2891 2892 IPFW_INC_RULE_COUNTER(f, pktlen); 2893 stack = (uint16_t *)(mtag + 1); 2894 2895 /* 2896 * The `call' action may use cached f_pos 2897 * (in f->next_rule), whose version is written 2898 * in f->next_rule. 2899 * The `return' action, however, doesn't have 2900 * fixed jump address in cmd->arg1 and can't use 2901 * cache. 2902 */ 2903 if (IS_CALL) { 2904 stack[mtag->m_tag_id] = f->rulenum; 2905 mtag->m_tag_id++; 2906 f_pos = JUMP(chain, f, cmd->arg1, 2907 tablearg, 1); 2908 } else { /* `return' action */ 2909 mtag->m_tag_id--; 2910 jmpto = stack[mtag->m_tag_id] + 1; 2911 f_pos = ipfw_find_rule(chain, jmpto, 0); 2912 } 2913 2914 /* 2915 * Skip disabled rules, and re-enter 2916 * the inner loop with the correct 2917 * f_pos, f, l and cmd. 2918 * Also clear cmdlen and skip_or 2919 */ 2920 for (; f_pos < chain->n_rules - 1 && 2921 (V_set_disable & 2922 (1 << chain->map[f_pos]->set)); f_pos++) 2923 ; 2924 /* Re-enter the inner loop at the dest rule. */ 2925 f = chain->map[f_pos]; 2926 l = f->cmd_len; 2927 cmd = f->cmd; 2928 cmdlen = 0; 2929 skip_or = 0; 2930 continue; 2931 break; /* NOTREACHED */ 2932 } 2933 #undef IS_CALL 2934 #undef IS_RETURN 2935 2936 case O_REJECT: 2937 /* 2938 * Drop the packet and send a reject notice 2939 * if the packet is not ICMP (or is an ICMP 2940 * query), and it is not multicast/broadcast. 2941 */ 2942 if (hlen > 0 && is_ipv4 && offset == 0 && 2943 (proto != IPPROTO_ICMP || 2944 is_icmp_query(ICMP(ulp))) && 2945 !(m->m_flags & (M_BCAST|M_MCAST)) && 2946 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2947 send_reject(args, cmd->arg1, iplen, ip); 2948 m = args->m; 2949 } 2950 /* FALLTHROUGH */ 2951 #ifdef INET6 2952 case O_UNREACH6: 2953 if (hlen > 0 && is_ipv6 && 2954 ((offset & IP6F_OFF_MASK) == 0) && 2955 (proto != IPPROTO_ICMPV6 || 2956 (is_icmp6_query(icmp6_type) == 1)) && 2957 !(m->m_flags & (M_BCAST|M_MCAST)) && 2958 !IN6_IS_ADDR_MULTICAST( 2959 &args->f_id.dst_ip6)) { 2960 send_reject6(args, 2961 cmd->opcode == O_REJECT ? 2962 map_icmp_unreach(cmd->arg1): 2963 cmd->arg1, hlen, 2964 (struct ip6_hdr *)ip); 2965 m = args->m; 2966 } 2967 /* FALLTHROUGH */ 2968 #endif 2969 case O_DENY: 2970 retval = IP_FW_DENY; 2971 l = 0; /* exit inner loop */ 2972 done = 1; /* exit outer loop */ 2973 break; 2974 2975 case O_FORWARD_IP: 2976 if (args->flags & IPFW_ARGS_ETHER) 2977 break; /* not valid on layer2 pkts */ 2978 if (q != f || 2979 dyn_info.direction == MATCH_FORWARD) { 2980 struct sockaddr_in *sa; 2981 2982 sa = &(((ipfw_insn_sa *)cmd)->sa); 2983 if (sa->sin_addr.s_addr == INADDR_ANY) { 2984 #ifdef INET6 2985 /* 2986 * We use O_FORWARD_IP opcode for 2987 * fwd rule with tablearg, but tables 2988 * now support IPv6 addresses. And 2989 * when we are inspecting IPv6 packet, 2990 * we can use nh6 field from 2991 * table_value as next_hop6 address. 2992 */ 2993 if (is_ipv6) { 2994 struct ip_fw_nh6 *nh6; 2995 2996 args->flags |= IPFW_ARGS_NH6; 2997 nh6 = &args->hopstore6; 2998 nh6->sin6_addr = TARG_VAL( 2999 chain, tablearg, nh6); 3000 nh6->sin6_port = sa->sin_port; 3001 nh6->sin6_scope_id = TARG_VAL( 3002 chain, tablearg, zoneid); 3003 } else 3004 #endif 3005 { 3006 args->flags |= IPFW_ARGS_NH4; 3007 args->hopstore.sin_port = 3008 sa->sin_port; 3009 sa = &args->hopstore; 3010 sa->sin_family = AF_INET; 3011 sa->sin_len = sizeof(*sa); 3012 sa->sin_addr.s_addr = htonl( 3013 TARG_VAL(chain, tablearg, 3014 nh4)); 3015 } 3016 } else { 3017 args->flags |= IPFW_ARGS_NH4PTR; 3018 args->next_hop = sa; 3019 } 3020 } 3021 retval = IP_FW_PASS; 3022 l = 0; /* exit inner loop */ 3023 done = 1; /* exit outer loop */ 3024 break; 3025 3026 #ifdef INET6 3027 case O_FORWARD_IP6: 3028 if (args->flags & IPFW_ARGS_ETHER) 3029 break; /* not valid on layer2 pkts */ 3030 if (q != f || 3031 dyn_info.direction == MATCH_FORWARD) { 3032 struct sockaddr_in6 *sin6; 3033 3034 sin6 = &(((ipfw_insn_sa6 *)cmd)->sa); 3035 args->flags |= IPFW_ARGS_NH6PTR; 3036 args->next_hop6 = sin6; 3037 } 3038 retval = IP_FW_PASS; 3039 l = 0; /* exit inner loop */ 3040 done = 1; /* exit outer loop */ 3041 break; 3042 #endif 3043 3044 case O_NETGRAPH: 3045 case O_NGTEE: 3046 set_match(args, f_pos, chain); 3047 args->rule.info = TARG(cmd->arg1, netgraph); 3048 if (V_fw_one_pass) 3049 args->rule.info |= IPFW_ONEPASS; 3050 retval = (cmd->opcode == O_NETGRAPH) ? 3051 IP_FW_NETGRAPH : IP_FW_NGTEE; 3052 l = 0; /* exit inner loop */ 3053 done = 1; /* exit outer loop */ 3054 break; 3055 3056 case O_SETFIB: { 3057 uint32_t fib; 3058 3059 IPFW_INC_RULE_COUNTER(f, pktlen); 3060 fib = TARG(cmd->arg1, fib) & 0x7FFF; 3061 if (fib >= rt_numfibs) 3062 fib = 0; 3063 M_SETFIB(m, fib); 3064 args->f_id.fib = fib; /* XXX */ 3065 l = 0; /* exit inner loop */ 3066 break; 3067 } 3068 3069 case O_SETDSCP: { 3070 uint16_t code; 3071 3072 code = TARG(cmd->arg1, dscp) & 0x3F; 3073 l = 0; /* exit inner loop */ 3074 if (is_ipv4) { 3075 uint16_t old; 3076 3077 old = *(uint16_t *)ip; 3078 ip->ip_tos = (code << 2) | 3079 (ip->ip_tos & 0x03); 3080 ip->ip_sum = cksum_adjust(ip->ip_sum, 3081 old, *(uint16_t *)ip); 3082 } else if (is_ipv6) { 3083 uint8_t *v; 3084 3085 v = &((struct ip6_hdr *)ip)->ip6_vfc; 3086 *v = (*v & 0xF0) | (code >> 2); 3087 v++; 3088 *v = (*v & 0x3F) | ((code & 0x03) << 6); 3089 } else 3090 break; 3091 3092 IPFW_INC_RULE_COUNTER(f, pktlen); 3093 break; 3094 } 3095 3096 case O_NAT: 3097 l = 0; /* exit inner loop */ 3098 done = 1; /* exit outer loop */ 3099 /* 3100 * Ensure that we do not invoke NAT handler for 3101 * non IPv4 packets. Libalias expects only IPv4. 3102 */ 3103 if (!is_ipv4 || !IPFW_NAT_LOADED) { 3104 retval = IP_FW_DENY; 3105 break; 3106 } 3107 3108 struct cfg_nat *t; 3109 int nat_id; 3110 3111 args->rule.info = 0; 3112 set_match(args, f_pos, chain); 3113 /* Check if this is 'global' nat rule */ 3114 if (cmd->arg1 == IP_FW_NAT44_GLOBAL) { 3115 retval = ipfw_nat_ptr(args, NULL, m); 3116 break; 3117 } 3118 t = ((ipfw_insn_nat *)cmd)->nat; 3119 if (t == NULL) { 3120 nat_id = TARG(cmd->arg1, nat); 3121 t = (*lookup_nat_ptr)(&chain->nat, nat_id); 3122 3123 if (t == NULL) { 3124 retval = IP_FW_DENY; 3125 break; 3126 } 3127 if (cmd->arg1 != IP_FW_TARG) 3128 ((ipfw_insn_nat *)cmd)->nat = t; 3129 } 3130 retval = ipfw_nat_ptr(args, t, m); 3131 break; 3132 3133 case O_REASS: { 3134 int ip_off; 3135 3136 l = 0; /* in any case exit inner loop */ 3137 if (is_ipv6) /* IPv6 is not supported yet */ 3138 break; 3139 IPFW_INC_RULE_COUNTER(f, pktlen); 3140 ip_off = ntohs(ip->ip_off); 3141 3142 /* if not fragmented, go to next rule */ 3143 if ((ip_off & (IP_MF | IP_OFFMASK)) == 0) 3144 break; 3145 3146 args->m = m = ip_reass(m); 3147 3148 /* 3149 * do IP header checksum fixup. 3150 */ 3151 if (m == NULL) { /* fragment got swallowed */ 3152 retval = IP_FW_DENY; 3153 } else { /* good, packet complete */ 3154 int hlen; 3155 3156 ip = mtod(m, struct ip *); 3157 hlen = ip->ip_hl << 2; 3158 ip->ip_sum = 0; 3159 if (hlen == sizeof(struct ip)) 3160 ip->ip_sum = in_cksum_hdr(ip); 3161 else 3162 ip->ip_sum = in_cksum(m, hlen); 3163 retval = IP_FW_REASS; 3164 args->rule.info = 0; 3165 set_match(args, f_pos, chain); 3166 } 3167 done = 1; /* exit outer loop */ 3168 break; 3169 } 3170 case O_EXTERNAL_ACTION: 3171 l = 0; /* in any case exit inner loop */ 3172 retval = ipfw_run_eaction(chain, args, 3173 cmd, &done); 3174 /* 3175 * If both @retval and @done are zero, 3176 * consider this as rule matching and 3177 * update counters. 3178 */ 3179 if (retval == 0 && done == 0) { 3180 IPFW_INC_RULE_COUNTER(f, pktlen); 3181 /* 3182 * Reset the result of the last 3183 * dynamic state lookup. 3184 * External action can change 3185 * @args content, and it may be 3186 * used for new state lookup later. 3187 */ 3188 DYN_INFO_INIT(&dyn_info); 3189 } 3190 break; 3191 3192 default: 3193 panic("-- unknown opcode %d\n", cmd->opcode); 3194 } /* end of switch() on opcodes */ 3195 /* 3196 * if we get here with l=0, then match is irrelevant. 3197 */ 3198 3199 if (cmd->len & F_NOT) 3200 match = !match; 3201 3202 if (match) { 3203 if (cmd->len & F_OR) 3204 skip_or = 1; 3205 } else { 3206 if (!(cmd->len & F_OR)) /* not an OR block, */ 3207 break; /* try next rule */ 3208 } 3209 3210 } /* end of inner loop, scan opcodes */ 3211 #undef PULLUP_LEN 3212 #undef PULLUP_LEN_LOCKED 3213 3214 if (done) 3215 break; 3216 3217 /* next_rule:; */ /* try next rule */ 3218 3219 } /* end of outer for, scan rules */ 3220 3221 if (done) { 3222 struct ip_fw *rule = chain->map[f_pos]; 3223 /* Update statistics */ 3224 IPFW_INC_RULE_COUNTER(rule, pktlen); 3225 } else { 3226 retval = IP_FW_DENY; 3227 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 3228 } 3229 IPFW_PF_RUNLOCK(chain); 3230 #ifdef __FreeBSD__ 3231 if (ucred_cache != NULL) 3232 crfree(ucred_cache); 3233 #endif 3234 return (retval); 3235 3236 pullup_failed: 3237 if (V_fw_verbose) 3238 printf("ipfw: pullup failed\n"); 3239 return (IP_FW_DENY); 3240 } 3241 3242 /* 3243 * Set maximum number of tables that can be used in given VNET ipfw instance. 3244 */ 3245 #ifdef SYSCTL_NODE 3246 static int 3247 sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS) 3248 { 3249 int error; 3250 unsigned int ntables; 3251 3252 ntables = V_fw_tables_max; 3253 3254 error = sysctl_handle_int(oidp, &ntables, 0, req); 3255 /* Read operation or some error */ 3256 if ((error != 0) || (req->newptr == NULL)) 3257 return (error); 3258 3259 return (ipfw_resize_tables(&V_layer3_chain, ntables)); 3260 } 3261 3262 /* 3263 * Switches table namespace between global and per-set. 3264 */ 3265 static int 3266 sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS) 3267 { 3268 int error; 3269 unsigned int sets; 3270 3271 sets = V_fw_tables_sets; 3272 3273 error = sysctl_handle_int(oidp, &sets, 0, req); 3274 /* Read operation or some error */ 3275 if ((error != 0) || (req->newptr == NULL)) 3276 return (error); 3277 3278 return (ipfw_switch_tables_namespace(&V_layer3_chain, sets)); 3279 } 3280 #endif 3281 3282 /* 3283 * Module and VNET glue 3284 */ 3285 3286 /* 3287 * Stuff that must be initialised only on boot or module load 3288 */ 3289 static int 3290 ipfw_init(void) 3291 { 3292 int error = 0; 3293 3294 /* 3295 * Only print out this stuff the first time around, 3296 * when called from the sysinit code. 3297 */ 3298 printf("ipfw2 " 3299 #ifdef INET6 3300 "(+ipv6) " 3301 #endif 3302 "initialized, divert %s, nat %s, " 3303 "default to %s, logging ", 3304 #ifdef IPDIVERT 3305 "enabled", 3306 #else 3307 "loadable", 3308 #endif 3309 #ifdef IPFIREWALL_NAT 3310 "enabled", 3311 #else 3312 "loadable", 3313 #endif 3314 default_to_accept ? "accept" : "deny"); 3315 3316 /* 3317 * Note: V_xxx variables can be accessed here but the vnet specific 3318 * initializer may not have been called yet for the VIMAGE case. 3319 * Tuneables will have been processed. We will print out values for 3320 * the default vnet. 3321 * XXX This should all be rationalized AFTER 8.0 3322 */ 3323 if (V_fw_verbose == 0) 3324 printf("disabled\n"); 3325 else if (V_verbose_limit == 0) 3326 printf("unlimited\n"); 3327 else 3328 printf("limited to %d packets/entry by default\n", 3329 V_verbose_limit); 3330 3331 /* Check user-supplied table count for validness */ 3332 if (default_fw_tables > IPFW_TABLES_MAX) 3333 default_fw_tables = IPFW_TABLES_MAX; 3334 3335 ipfw_init_sopt_handler(); 3336 ipfw_init_obj_rewriter(); 3337 ipfw_iface_init(); 3338 return (error); 3339 } 3340 3341 /* 3342 * Called for the removal of the last instance only on module unload. 3343 */ 3344 static void 3345 ipfw_destroy(void) 3346 { 3347 3348 ipfw_iface_destroy(); 3349 ipfw_destroy_sopt_handler(); 3350 ipfw_destroy_obj_rewriter(); 3351 printf("IP firewall unloaded\n"); 3352 } 3353 3354 /* 3355 * Stuff that must be initialized for every instance 3356 * (including the first of course). 3357 */ 3358 static int 3359 vnet_ipfw_init(const void *unused) 3360 { 3361 int error, first; 3362 struct ip_fw *rule = NULL; 3363 struct ip_fw_chain *chain; 3364 3365 chain = &V_layer3_chain; 3366 3367 first = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 3368 3369 /* First set up some values that are compile time options */ 3370 V_autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 3371 V_fw_deny_unknown_exthdrs = 1; 3372 #ifdef IPFIREWALL_VERBOSE 3373 V_fw_verbose = 1; 3374 #endif 3375 #ifdef IPFIREWALL_VERBOSE_LIMIT 3376 V_verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 3377 #endif 3378 #ifdef IPFIREWALL_NAT 3379 LIST_INIT(&chain->nat); 3380 #endif 3381 3382 /* Init shared services hash table */ 3383 ipfw_init_srv(chain); 3384 3385 ipfw_init_counters(); 3386 /* Set initial number of tables */ 3387 V_fw_tables_max = default_fw_tables; 3388 error = ipfw_init_tables(chain, first); 3389 if (error) { 3390 printf("ipfw2: setting up tables failed\n"); 3391 free(chain->map, M_IPFW); 3392 free(rule, M_IPFW); 3393 return (ENOSPC); 3394 } 3395 3396 IPFW_LOCK_INIT(chain); 3397 3398 /* fill and insert the default rule */ 3399 rule = ipfw_alloc_rule(chain, sizeof(struct ip_fw)); 3400 rule->flags |= IPFW_RULE_NOOPT; 3401 rule->cmd_len = 1; 3402 rule->cmd[0].len = 1; 3403 rule->cmd[0].opcode = default_to_accept ? O_ACCEPT : O_DENY; 3404 chain->default_rule = rule; 3405 ipfw_add_protected_rule(chain, rule, 0); 3406 3407 ipfw_dyn_init(chain); 3408 ipfw_eaction_init(chain, first); 3409 #ifdef LINEAR_SKIPTO 3410 ipfw_init_skipto_cache(chain); 3411 #endif 3412 ipfw_bpf_init(first); 3413 3414 /* First set up some values that are compile time options */ 3415 V_ipfw_vnet_ready = 1; /* Open for business */ 3416 3417 /* 3418 * Hook the sockopt handler and pfil hooks for ipv4 and ipv6. 3419 * Even if the latter two fail we still keep the module alive 3420 * because the sockopt and layer2 paths are still useful. 3421 * ipfw[6]_hook return 0 on success, ENOENT on failure, 3422 * so we can ignore the exact return value and just set a flag. 3423 * 3424 * Note that V_fw[6]_enable are manipulated by a SYSCTL_PROC so 3425 * changes in the underlying (per-vnet) variables trigger 3426 * immediate hook()/unhook() calls. 3427 * In layer2 we have the same behaviour, except that V_ether_ipfw 3428 * is checked on each packet because there are no pfil hooks. 3429 */ 3430 V_ip_fw_ctl_ptr = ipfw_ctl3; 3431 error = ipfw_attach_hooks(); 3432 return (error); 3433 } 3434 3435 /* 3436 * Called for the removal of each instance. 3437 */ 3438 static int 3439 vnet_ipfw_uninit(const void *unused) 3440 { 3441 struct ip_fw *reap; 3442 struct ip_fw_chain *chain = &V_layer3_chain; 3443 int i, last; 3444 3445 V_ipfw_vnet_ready = 0; /* tell new callers to go away */ 3446 /* 3447 * disconnect from ipv4, ipv6, layer2 and sockopt. 3448 * Then grab, release and grab again the WLOCK so we make 3449 * sure the update is propagated and nobody will be in. 3450 */ 3451 ipfw_detach_hooks(); 3452 V_ip_fw_ctl_ptr = NULL; 3453 3454 last = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 3455 3456 IPFW_UH_WLOCK(chain); 3457 IPFW_UH_WUNLOCK(chain); 3458 3459 ipfw_dyn_uninit(0); /* run the callout_drain */ 3460 3461 IPFW_UH_WLOCK(chain); 3462 3463 reap = NULL; 3464 IPFW_WLOCK(chain); 3465 for (i = 0; i < chain->n_rules; i++) 3466 ipfw_reap_add(chain, &reap, chain->map[i]); 3467 free(chain->map, M_IPFW); 3468 #ifdef LINEAR_SKIPTO 3469 ipfw_destroy_skipto_cache(chain); 3470 #endif 3471 IPFW_WUNLOCK(chain); 3472 IPFW_UH_WUNLOCK(chain); 3473 ipfw_destroy_tables(chain, last); 3474 ipfw_eaction_uninit(chain, last); 3475 if (reap != NULL) 3476 ipfw_reap_rules(reap); 3477 vnet_ipfw_iface_destroy(chain); 3478 ipfw_destroy_srv(chain); 3479 IPFW_LOCK_DESTROY(chain); 3480 ipfw_dyn_uninit(1); /* free the remaining parts */ 3481 ipfw_destroy_counters(); 3482 ipfw_bpf_uninit(last); 3483 return (0); 3484 } 3485 3486 /* 3487 * Module event handler. 3488 * In general we have the choice of handling most of these events by the 3489 * event handler or by the (VNET_)SYS(UN)INIT handlers. I have chosen to 3490 * use the SYSINIT handlers as they are more capable of expressing the 3491 * flow of control during module and vnet operations, so this is just 3492 * a skeleton. Note there is no SYSINIT equivalent of the module 3493 * SHUTDOWN handler, but we don't have anything to do in that case anyhow. 3494 */ 3495 static int 3496 ipfw_modevent(module_t mod, int type, void *unused) 3497 { 3498 int err = 0; 3499 3500 switch (type) { 3501 case MOD_LOAD: 3502 /* Called once at module load or 3503 * system boot if compiled in. */ 3504 break; 3505 case MOD_QUIESCE: 3506 /* Called before unload. May veto unloading. */ 3507 break; 3508 case MOD_UNLOAD: 3509 /* Called during unload. */ 3510 break; 3511 case MOD_SHUTDOWN: 3512 /* Called during system shutdown. */ 3513 break; 3514 default: 3515 err = EOPNOTSUPP; 3516 break; 3517 } 3518 return err; 3519 } 3520 3521 static moduledata_t ipfwmod = { 3522 "ipfw", 3523 ipfw_modevent, 3524 0 3525 }; 3526 3527 /* Define startup order. */ 3528 #define IPFW_SI_SUB_FIREWALL SI_SUB_PROTO_FIREWALL 3529 #define IPFW_MODEVENT_ORDER (SI_ORDER_ANY - 255) /* On boot slot in here. */ 3530 #define IPFW_MODULE_ORDER (IPFW_MODEVENT_ORDER + 1) /* A little later. */ 3531 #define IPFW_VNET_ORDER (IPFW_MODEVENT_ORDER + 2) /* Later still. */ 3532 3533 DECLARE_MODULE(ipfw, ipfwmod, IPFW_SI_SUB_FIREWALL, IPFW_MODEVENT_ORDER); 3534 FEATURE(ipfw_ctl3, "ipfw new sockopt calls"); 3535 MODULE_VERSION(ipfw, 3); 3536 /* should declare some dependencies here */ 3537 3538 /* 3539 * Starting up. Done in order after ipfwmod() has been called. 3540 * VNET_SYSINIT is also called for each existing vnet and each new vnet. 3541 */ 3542 SYSINIT(ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 3543 ipfw_init, NULL); 3544 VNET_SYSINIT(vnet_ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 3545 vnet_ipfw_init, NULL); 3546 3547 /* 3548 * Closing up shop. These are done in REVERSE ORDER, but still 3549 * after ipfwmod() has been called. Not called on reboot. 3550 * VNET_SYSUNINIT is also called for each exiting vnet as it exits. 3551 * or when the module is unloaded. 3552 */ 3553 SYSUNINIT(ipfw_destroy, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 3554 ipfw_destroy, NULL); 3555 VNET_SYSUNINIT(vnet_ipfw_uninit, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 3556 vnet_ipfw_uninit, NULL); 3557 /* end of file */ 3558