1 /*- 2 * Copyright (c) 2002-2009 Luigi Rizzo, Universita` di Pisa 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 /* 30 * The FreeBSD IP packet firewall, main file 31 */ 32 33 #include "opt_ipfw.h" 34 #include "opt_ipdivert.h" 35 #include "opt_inet.h" 36 #ifndef INET 37 #error "IPFIREWALL requires INET" 38 #endif /* INET */ 39 #include "opt_inet6.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/condvar.h> 44 #include <sys/counter.h> 45 #include <sys/eventhandler.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #include <sys/kernel.h> 49 #include <sys/lock.h> 50 #include <sys/jail.h> 51 #include <sys/module.h> 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/rwlock.h> 55 #include <sys/rmlock.h> 56 #include <sys/socket.h> 57 #include <sys/socketvar.h> 58 #include <sys/sysctl.h> 59 #include <sys/syslog.h> 60 #include <sys/ucred.h> 61 #include <net/ethernet.h> /* for ETHERTYPE_IP */ 62 #include <net/if.h> 63 #include <net/if_var.h> 64 #include <net/route.h> 65 #include <net/pfil.h> 66 #include <net/vnet.h> 67 68 #include <netpfil/pf/pf_mtag.h> 69 70 #include <netinet/in.h> 71 #include <netinet/in_var.h> 72 #include <netinet/in_pcb.h> 73 #include <netinet/ip.h> 74 #include <netinet/ip_var.h> 75 #include <netinet/ip_icmp.h> 76 #include <netinet/ip_fw.h> 77 #include <netinet/ip_carp.h> 78 #include <netinet/pim.h> 79 #include <netinet/tcp_var.h> 80 #include <netinet/udp.h> 81 #include <netinet/udp_var.h> 82 #include <netinet/sctp.h> 83 84 #include <netinet/ip6.h> 85 #include <netinet/icmp6.h> 86 #include <netinet/in_fib.h> 87 #ifdef INET6 88 #include <netinet6/in6_fib.h> 89 #include <netinet6/in6_pcb.h> 90 #include <netinet6/scope6_var.h> 91 #include <netinet6/ip6_var.h> 92 #endif 93 94 #include <net/if_gre.h> /* for struct grehdr */ 95 96 #include <netpfil/ipfw/ip_fw_private.h> 97 98 #include <machine/in_cksum.h> /* XXX for in_cksum */ 99 100 #ifdef MAC 101 #include <security/mac/mac_framework.h> 102 #endif 103 104 /* 105 * static variables followed by global ones. 106 * All ipfw global variables are here. 107 */ 108 109 static VNET_DEFINE(int, fw_deny_unknown_exthdrs); 110 #define V_fw_deny_unknown_exthdrs VNET(fw_deny_unknown_exthdrs) 111 112 static VNET_DEFINE(int, fw_permit_single_frag6) = 1; 113 #define V_fw_permit_single_frag6 VNET(fw_permit_single_frag6) 114 115 #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 116 static int default_to_accept = 1; 117 #else 118 static int default_to_accept; 119 #endif 120 121 VNET_DEFINE(int, autoinc_step); 122 VNET_DEFINE(int, fw_one_pass) = 1; 123 124 VNET_DEFINE(unsigned int, fw_tables_max); 125 VNET_DEFINE(unsigned int, fw_tables_sets) = 0; /* Don't use set-aware tables */ 126 /* Use 128 tables by default */ 127 static unsigned int default_fw_tables = IPFW_TABLES_DEFAULT; 128 129 #ifndef LINEAR_SKIPTO 130 static int jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 131 int tablearg, int jump_backwards); 132 #define JUMP(ch, f, num, targ, back) jump_fast(ch, f, num, targ, back) 133 #else 134 static int jump_linear(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_linear(ch, f, num, targ, back) 137 #endif 138 139 /* 140 * Each rule belongs to one of 32 different sets (0..31). 141 * The variable set_disable contains one bit per set. 142 * If the bit is set, all rules in the corresponding set 143 * are disabled. Set RESVD_SET(31) is reserved for the default rule 144 * and rules that are not deleted by the flush command, 145 * and CANNOT be disabled. 146 * Rules in set RESVD_SET can only be deleted individually. 147 */ 148 VNET_DEFINE(u_int32_t, set_disable); 149 #define V_set_disable VNET(set_disable) 150 151 VNET_DEFINE(int, fw_verbose); 152 /* counter for ipfw_log(NULL...) */ 153 VNET_DEFINE(u_int64_t, norule_counter); 154 VNET_DEFINE(int, verbose_limit); 155 156 /* layer3_chain contains the list of rules for layer 3 */ 157 VNET_DEFINE(struct ip_fw_chain, layer3_chain); 158 159 /* ipfw_vnet_ready controls when we are open for business */ 160 VNET_DEFINE(int, ipfw_vnet_ready) = 0; 161 162 VNET_DEFINE(int, ipfw_nat_ready) = 0; 163 164 ipfw_nat_t *ipfw_nat_ptr = NULL; 165 struct cfg_nat *(*lookup_nat_ptr)(struct nat_list *, int); 166 ipfw_nat_cfg_t *ipfw_nat_cfg_ptr; 167 ipfw_nat_cfg_t *ipfw_nat_del_ptr; 168 ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr; 169 ipfw_nat_cfg_t *ipfw_nat_get_log_ptr; 170 171 #ifdef SYSCTL_NODE 172 uint32_t dummy_def = IPFW_DEFAULT_RULE; 173 static int sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS); 174 static int sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS); 175 176 SYSBEGIN(f3) 177 178 SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 179 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 180 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_one_pass), 0, 181 "Only do a single pass through ipfw when using dummynet(4)"); 182 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, 183 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(autoinc_step), 0, 184 "Rule number auto-increment step"); 185 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, 186 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_verbose), 0, 187 "Log matches to ipfw rules"); 188 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, 189 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(verbose_limit), 0, 190 "Set upper limit of matches of ipfw rules logged"); 191 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, default_rule, CTLFLAG_RD, 192 &dummy_def, 0, 193 "The default/max possible rule number."); 194 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_max, 195 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_table_num, "IU", 196 "Maximum number of concurrently used tables"); 197 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_sets, 198 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 199 0, 0, sysctl_ipfw_tables_sets, "IU", 200 "Use per-set namespace for tables"); 201 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, default_to_accept, CTLFLAG_RDTUN, 202 &default_to_accept, 0, 203 "Make the default rule accept all packets."); 204 TUNABLE_INT("net.inet.ip.fw.tables_max", (int *)&default_fw_tables); 205 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, 206 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(layer3_chain.n_rules), 0, 207 "Number of static rules"); 208 209 #ifdef INET6 210 SYSCTL_DECL(_net_inet6_ip6); 211 SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 212 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, deny_unknown_exthdrs, 213 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 214 &VNET_NAME(fw_deny_unknown_exthdrs), 0, 215 "Deny packets with unknown IPv6 Extension Headers"); 216 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, permit_single_frag6, 217 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 218 &VNET_NAME(fw_permit_single_frag6), 0, 219 "Permit single packet IPv6 fragments"); 220 #endif /* INET6 */ 221 222 SYSEND 223 224 #endif /* SYSCTL_NODE */ 225 226 227 /* 228 * Some macros used in the various matching options. 229 * L3HDR maps an ipv4 pointer into a layer3 header pointer of type T 230 * Other macros just cast void * into the appropriate type 231 */ 232 #define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 233 #define TCP(p) ((struct tcphdr *)(p)) 234 #define SCTP(p) ((struct sctphdr *)(p)) 235 #define UDP(p) ((struct udphdr *)(p)) 236 #define ICMP(p) ((struct icmphdr *)(p)) 237 #define ICMP6(p) ((struct icmp6_hdr *)(p)) 238 239 static __inline int 240 icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd) 241 { 242 int type = icmp->icmp_type; 243 244 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 245 } 246 247 #define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 248 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 249 250 static int 251 is_icmp_query(struct icmphdr *icmp) 252 { 253 int type = icmp->icmp_type; 254 255 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 256 } 257 #undef TT 258 259 /* 260 * The following checks use two arrays of 8 or 16 bits to store the 261 * bits that we want set or clear, respectively. They are in the 262 * low and high half of cmd->arg1 or cmd->d[0]. 263 * 264 * We scan options and store the bits we find set. We succeed if 265 * 266 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 267 * 268 * The code is sometimes optimized not to store additional variables. 269 */ 270 271 static int 272 flags_match(ipfw_insn *cmd, u_int8_t bits) 273 { 274 u_char want_clear; 275 bits = ~bits; 276 277 if ( ((cmd->arg1 & 0xff) & bits) != 0) 278 return 0; /* some bits we want set were clear */ 279 want_clear = (cmd->arg1 >> 8) & 0xff; 280 if ( (want_clear & bits) != want_clear) 281 return 0; /* some bits we want clear were set */ 282 return 1; 283 } 284 285 static int 286 ipopts_match(struct ip *ip, ipfw_insn *cmd) 287 { 288 int optlen, bits = 0; 289 u_char *cp = (u_char *)(ip + 1); 290 int x = (ip->ip_hl << 2) - sizeof (struct ip); 291 292 for (; x > 0; x -= optlen, cp += optlen) { 293 int opt = cp[IPOPT_OPTVAL]; 294 295 if (opt == IPOPT_EOL) 296 break; 297 if (opt == IPOPT_NOP) 298 optlen = 1; 299 else { 300 optlen = cp[IPOPT_OLEN]; 301 if (optlen <= 0 || optlen > x) 302 return 0; /* invalid or truncated */ 303 } 304 switch (opt) { 305 306 default: 307 break; 308 309 case IPOPT_LSRR: 310 bits |= IP_FW_IPOPT_LSRR; 311 break; 312 313 case IPOPT_SSRR: 314 bits |= IP_FW_IPOPT_SSRR; 315 break; 316 317 case IPOPT_RR: 318 bits |= IP_FW_IPOPT_RR; 319 break; 320 321 case IPOPT_TS: 322 bits |= IP_FW_IPOPT_TS; 323 break; 324 } 325 } 326 return (flags_match(cmd, bits)); 327 } 328 329 static int 330 tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd) 331 { 332 int optlen, bits = 0; 333 u_char *cp = (u_char *)(tcp + 1); 334 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 335 336 for (; x > 0; x -= optlen, cp += optlen) { 337 int opt = cp[0]; 338 if (opt == TCPOPT_EOL) 339 break; 340 if (opt == TCPOPT_NOP) 341 optlen = 1; 342 else { 343 optlen = cp[1]; 344 if (optlen <= 0) 345 break; 346 } 347 348 switch (opt) { 349 350 default: 351 break; 352 353 case TCPOPT_MAXSEG: 354 bits |= IP_FW_TCPOPT_MSS; 355 break; 356 357 case TCPOPT_WINDOW: 358 bits |= IP_FW_TCPOPT_WINDOW; 359 break; 360 361 case TCPOPT_SACK_PERMITTED: 362 case TCPOPT_SACK: 363 bits |= IP_FW_TCPOPT_SACK; 364 break; 365 366 case TCPOPT_TIMESTAMP: 367 bits |= IP_FW_TCPOPT_TS; 368 break; 369 370 } 371 } 372 return (flags_match(cmd, bits)); 373 } 374 375 static int 376 iface_match(struct ifnet *ifp, ipfw_insn_if *cmd, struct ip_fw_chain *chain, 377 uint32_t *tablearg) 378 { 379 380 if (ifp == NULL) /* no iface with this packet, match fails */ 381 return (0); 382 383 /* Check by name or by IP address */ 384 if (cmd->name[0] != '\0') { /* match by name */ 385 if (cmd->name[0] == '\1') /* use tablearg to match */ 386 return ipfw_lookup_table(chain, cmd->p.kidx, 0, 387 &ifp->if_index, tablearg); 388 /* Check name */ 389 if (cmd->p.glob) { 390 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 391 return(1); 392 } else { 393 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 394 return(1); 395 } 396 } else { 397 #if !defined(USERSPACE) && defined(__FreeBSD__) /* and OSX too ? */ 398 struct ifaddr *ia; 399 400 if_addr_rlock(ifp); 401 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 402 if (ia->ifa_addr->sa_family != AF_INET) 403 continue; 404 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 405 (ia->ifa_addr))->sin_addr.s_addr) { 406 if_addr_runlock(ifp); 407 return(1); /* match */ 408 } 409 } 410 if_addr_runlock(ifp); 411 #endif /* __FreeBSD__ */ 412 } 413 return(0); /* no match, fail ... */ 414 } 415 416 /* 417 * The verify_path function checks if a route to the src exists and 418 * if it is reachable via ifp (when provided). 419 * 420 * The 'verrevpath' option checks that the interface that an IP packet 421 * arrives on is the same interface that traffic destined for the 422 * packet's source address would be routed out of. 423 * The 'versrcreach' option just checks that the source address is 424 * reachable via any route (except default) in the routing table. 425 * These two are a measure to block forged packets. This is also 426 * commonly known as "anti-spoofing" or Unicast Reverse Path 427 * Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 428 * is purposely reminiscent of the Cisco IOS command, 429 * 430 * ip verify unicast reverse-path 431 * ip verify unicast source reachable-via any 432 * 433 * which implements the same functionality. But note that the syntax 434 * is misleading, and the check may be performed on all IP packets 435 * whether unicast, multicast, or broadcast. 436 */ 437 static int 438 verify_path(struct in_addr src, struct ifnet *ifp, u_int fib) 439 { 440 #if defined(USERSPACE) || !defined(__FreeBSD__) 441 return 0; 442 #else 443 struct nhop4_basic nh4; 444 445 if (fib4_lookup_nh_basic(fib, src, NHR_IFAIF, 0, &nh4) != 0) 446 return (0); 447 448 /* 449 * If ifp is provided, check for equality with rtentry. 450 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 451 * in order to pass packets injected back by if_simloop(): 452 * routing entry (via lo0) for our own address 453 * may exist, so we need to handle routing assymetry. 454 */ 455 if (ifp != NULL && ifp != nh4.nh_ifp) 456 return (0); 457 458 /* if no ifp provided, check if rtentry is not default route */ 459 if (ifp == NULL && (nh4.nh_flags & NHF_DEFAULT) != 0) 460 return (0); 461 462 /* or if this is a blackhole/reject route */ 463 if (ifp == NULL && (nh4.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 464 return (0); 465 466 /* found valid route */ 467 return 1; 468 #endif /* __FreeBSD__ */ 469 } 470 471 #ifdef INET6 472 /* 473 * ipv6 specific rules here... 474 */ 475 static __inline int 476 icmp6type_match (int type, ipfw_insn_u32 *cmd) 477 { 478 return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) ); 479 } 480 481 static int 482 flow6id_match( int curr_flow, ipfw_insn_u32 *cmd ) 483 { 484 int i; 485 for (i=0; i <= cmd->o.arg1; ++i ) 486 if (curr_flow == cmd->d[i] ) 487 return 1; 488 return 0; 489 } 490 491 /* support for IP6_*_ME opcodes */ 492 static const struct in6_addr lla_mask = {{{ 493 0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 494 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff 495 }}}; 496 497 static int 498 ipfw_localip6(struct in6_addr *in6) 499 { 500 struct rm_priotracker in6_ifa_tracker; 501 struct in6_ifaddr *ia; 502 503 if (IN6_IS_ADDR_MULTICAST(in6)) 504 return (0); 505 506 if (!IN6_IS_ADDR_LINKLOCAL(in6)) 507 return (in6_localip(in6)); 508 509 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 510 TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 511 if (!IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) 512 continue; 513 if (IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr, 514 in6, &lla_mask)) { 515 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 516 return (1); 517 } 518 } 519 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 520 return (0); 521 } 522 523 static int 524 verify_path6(struct in6_addr *src, struct ifnet *ifp, u_int fib) 525 { 526 struct nhop6_basic nh6; 527 528 if (IN6_IS_SCOPE_LINKLOCAL(src)) 529 return (1); 530 531 if (fib6_lookup_nh_basic(fib, src, 0, NHR_IFAIF, 0, &nh6) != 0) 532 return (0); 533 534 /* If ifp is provided, check for equality with route table. */ 535 if (ifp != NULL && ifp != nh6.nh_ifp) 536 return (0); 537 538 /* if no ifp provided, check if rtentry is not default route */ 539 if (ifp == NULL && (nh6.nh_flags & NHF_DEFAULT) != 0) 540 return (0); 541 542 /* or if this is a blackhole/reject route */ 543 if (ifp == NULL && (nh6.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 544 return (0); 545 546 /* found valid route */ 547 return 1; 548 } 549 550 static int 551 is_icmp6_query(int icmp6_type) 552 { 553 if ((icmp6_type <= ICMP6_MAXTYPE) && 554 (icmp6_type == ICMP6_ECHO_REQUEST || 555 icmp6_type == ICMP6_MEMBERSHIP_QUERY || 556 icmp6_type == ICMP6_WRUREQUEST || 557 icmp6_type == ICMP6_FQDN_QUERY || 558 icmp6_type == ICMP6_NI_QUERY)) 559 return (1); 560 561 return (0); 562 } 563 564 static void 565 send_reject6(struct ip_fw_args *args, int code, u_int hlen, struct ip6_hdr *ip6) 566 { 567 struct mbuf *m; 568 569 m = args->m; 570 if (code == ICMP6_UNREACH_RST && args->f_id.proto == IPPROTO_TCP) { 571 struct tcphdr *tcp; 572 tcp = (struct tcphdr *)((char *)ip6 + hlen); 573 574 if ((tcp->th_flags & TH_RST) == 0) { 575 struct mbuf *m0; 576 m0 = ipfw_send_pkt(args->m, &(args->f_id), 577 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 578 tcp->th_flags | TH_RST); 579 if (m0 != NULL) 580 ip6_output(m0, NULL, NULL, 0, NULL, NULL, 581 NULL); 582 } 583 FREE_PKT(m); 584 } else if (code != ICMP6_UNREACH_RST) { /* Send an ICMPv6 unreach. */ 585 #if 0 586 /* 587 * Unlike above, the mbufs need to line up with the ip6 hdr, 588 * as the contents are read. We need to m_adj() the 589 * needed amount. 590 * The mbuf will however be thrown away so we can adjust it. 591 * Remember we did an m_pullup on it already so we 592 * can make some assumptions about contiguousness. 593 */ 594 if (args->L3offset) 595 m_adj(m, args->L3offset); 596 #endif 597 icmp6_error(m, ICMP6_DST_UNREACH, code, 0); 598 } else 599 FREE_PKT(m); 600 601 args->m = NULL; 602 } 603 604 #endif /* INET6 */ 605 606 607 /* 608 * sends a reject message, consuming the mbuf passed as an argument. 609 */ 610 static void 611 send_reject(struct ip_fw_args *args, int code, int iplen, struct ip *ip) 612 { 613 614 #if 0 615 /* XXX When ip is not guaranteed to be at mtod() we will 616 * need to account for this */ 617 * The mbuf will however be thrown away so we can adjust it. 618 * Remember we did an m_pullup on it already so we 619 * can make some assumptions about contiguousness. 620 */ 621 if (args->L3offset) 622 m_adj(m, args->L3offset); 623 #endif 624 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */ 625 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 626 } else if (args->f_id.proto == IPPROTO_TCP) { 627 struct tcphdr *const tcp = 628 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 629 if ( (tcp->th_flags & TH_RST) == 0) { 630 struct mbuf *m; 631 m = ipfw_send_pkt(args->m, &(args->f_id), 632 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 633 tcp->th_flags | TH_RST); 634 if (m != NULL) 635 ip_output(m, NULL, NULL, 0, NULL, NULL); 636 } 637 FREE_PKT(args->m); 638 } else 639 FREE_PKT(args->m); 640 args->m = NULL; 641 } 642 643 /* 644 * Support for uid/gid/jail lookup. These tests are expensive 645 * (because we may need to look into the list of active sockets) 646 * so we cache the results. ugid_lookupp is 0 if we have not 647 * yet done a lookup, 1 if we succeeded, and -1 if we tried 648 * and failed. The function always returns the match value. 649 * We could actually spare the variable and use *uc, setting 650 * it to '(void *)check_uidgid if we have no info, NULL if 651 * we tried and failed, or any other value if successful. 652 */ 653 static int 654 check_uidgid(ipfw_insn_u32 *insn, struct ip_fw_args *args, int *ugid_lookupp, 655 struct ucred **uc) 656 { 657 #if defined(USERSPACE) 658 return 0; // not supported in userspace 659 #else 660 #ifndef __FreeBSD__ 661 /* XXX */ 662 return cred_check(insn, proto, oif, 663 dst_ip, dst_port, src_ip, src_port, 664 (struct bsd_ucred *)uc, ugid_lookupp, ((struct mbuf *)inp)->m_skb); 665 #else /* FreeBSD */ 666 struct in_addr src_ip, dst_ip; 667 struct inpcbinfo *pi; 668 struct ipfw_flow_id *id; 669 struct inpcb *pcb, *inp; 670 struct ifnet *oif; 671 int lookupflags; 672 int match; 673 674 id = &args->f_id; 675 inp = args->inp; 676 oif = args->oif; 677 678 /* 679 * Check to see if the UDP or TCP stack supplied us with 680 * the PCB. If so, rather then holding a lock and looking 681 * up the PCB, we can use the one that was supplied. 682 */ 683 if (inp && *ugid_lookupp == 0) { 684 INP_LOCK_ASSERT(inp); 685 if (inp->inp_socket != NULL) { 686 *uc = crhold(inp->inp_cred); 687 *ugid_lookupp = 1; 688 } else 689 *ugid_lookupp = -1; 690 } 691 /* 692 * If we have already been here and the packet has no 693 * PCB entry associated with it, then we can safely 694 * assume that this is a no match. 695 */ 696 if (*ugid_lookupp == -1) 697 return (0); 698 if (id->proto == IPPROTO_TCP) { 699 lookupflags = 0; 700 pi = &V_tcbinfo; 701 } else if (id->proto == IPPROTO_UDP) { 702 lookupflags = INPLOOKUP_WILDCARD; 703 pi = &V_udbinfo; 704 } else 705 return 0; 706 lookupflags |= INPLOOKUP_RLOCKPCB; 707 match = 0; 708 if (*ugid_lookupp == 0) { 709 if (id->addr_type == 6) { 710 #ifdef INET6 711 if (oif == NULL) 712 pcb = in6_pcblookup_mbuf(pi, 713 &id->src_ip6, htons(id->src_port), 714 &id->dst_ip6, htons(id->dst_port), 715 lookupflags, oif, args->m); 716 else 717 pcb = in6_pcblookup_mbuf(pi, 718 &id->dst_ip6, htons(id->dst_port), 719 &id->src_ip6, htons(id->src_port), 720 lookupflags, oif, args->m); 721 #else 722 *ugid_lookupp = -1; 723 return (0); 724 #endif 725 } else { 726 src_ip.s_addr = htonl(id->src_ip); 727 dst_ip.s_addr = htonl(id->dst_ip); 728 if (oif == NULL) 729 pcb = in_pcblookup_mbuf(pi, 730 src_ip, htons(id->src_port), 731 dst_ip, htons(id->dst_port), 732 lookupflags, oif, args->m); 733 else 734 pcb = in_pcblookup_mbuf(pi, 735 dst_ip, htons(id->dst_port), 736 src_ip, htons(id->src_port), 737 lookupflags, oif, args->m); 738 } 739 if (pcb != NULL) { 740 INP_RLOCK_ASSERT(pcb); 741 *uc = crhold(pcb->inp_cred); 742 *ugid_lookupp = 1; 743 INP_RUNLOCK(pcb); 744 } 745 if (*ugid_lookupp == 0) { 746 /* 747 * We tried and failed, set the variable to -1 748 * so we will not try again on this packet. 749 */ 750 *ugid_lookupp = -1; 751 return (0); 752 } 753 } 754 if (insn->o.opcode == O_UID) 755 match = ((*uc)->cr_uid == (uid_t)insn->d[0]); 756 else if (insn->o.opcode == O_GID) 757 match = groupmember((gid_t)insn->d[0], *uc); 758 else if (insn->o.opcode == O_JAIL) 759 match = ((*uc)->cr_prison->pr_id == (int)insn->d[0]); 760 return (match); 761 #endif /* __FreeBSD__ */ 762 #endif /* not supported in userspace */ 763 } 764 765 /* 766 * Helper function to set args with info on the rule after the matching 767 * one. slot is precise, whereas we guess rule_id as they are 768 * assigned sequentially. 769 */ 770 static inline void 771 set_match(struct ip_fw_args *args, int slot, 772 struct ip_fw_chain *chain) 773 { 774 args->rule.chain_id = chain->id; 775 args->rule.slot = slot + 1; /* we use 0 as a marker */ 776 args->rule.rule_id = 1 + chain->map[slot]->id; 777 args->rule.rulenum = chain->map[slot]->rulenum; 778 } 779 780 #ifndef LINEAR_SKIPTO 781 /* 782 * Helper function to enable cached rule lookups using 783 * cached_id and cached_pos fields in ipfw rule. 784 */ 785 static int 786 jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 787 int tablearg, int jump_backwards) 788 { 789 int f_pos; 790 791 /* If possible use cached f_pos (in f->cached_pos), 792 * whose version is written in f->cached_id 793 * (horrible hacks to avoid changing the ABI). 794 */ 795 if (num != IP_FW_TARG && f->cached_id == chain->id) 796 f_pos = f->cached_pos; 797 else { 798 int i = IP_FW_ARG_TABLEARG(chain, num, skipto); 799 /* make sure we do not jump backward */ 800 if (jump_backwards == 0 && i <= f->rulenum) 801 i = f->rulenum + 1; 802 if (chain->idxmap != NULL) 803 f_pos = chain->idxmap[i]; 804 else 805 f_pos = ipfw_find_rule(chain, i, 0); 806 /* update the cache */ 807 if (num != IP_FW_TARG) { 808 f->cached_id = chain->id; 809 f->cached_pos = f_pos; 810 } 811 } 812 813 return (f_pos); 814 } 815 #else 816 /* 817 * Helper function to enable real fast rule lookups. 818 */ 819 static int 820 jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num, 821 int tablearg, int jump_backwards) 822 { 823 int f_pos; 824 825 num = IP_FW_ARG_TABLEARG(chain, num, skipto); 826 /* make sure we do not jump backward */ 827 if (jump_backwards == 0 && num <= f->rulenum) 828 num = f->rulenum + 1; 829 f_pos = chain->idxmap[num]; 830 831 return (f_pos); 832 } 833 #endif 834 835 #define TARG(k, f) IP_FW_ARG_TABLEARG(chain, k, f) 836 /* 837 * The main check routine for the firewall. 838 * 839 * All arguments are in args so we can modify them and return them 840 * back to the caller. 841 * 842 * Parameters: 843 * 844 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 845 * Starts with the IP header. 846 * args->eh (in) Mac header if present, NULL for layer3 packet. 847 * args->L3offset Number of bytes bypassed if we came from L2. 848 * e.g. often sizeof(eh) ** NOTYET ** 849 * args->oif Outgoing interface, NULL if packet is incoming. 850 * The incoming interface is in the mbuf. (in) 851 * args->divert_rule (in/out) 852 * Skip up to the first rule past this rule number; 853 * upon return, non-zero port number for divert or tee. 854 * 855 * args->rule Pointer to the last matching rule (in/out) 856 * args->next_hop Socket we are forwarding to (out). 857 * args->next_hop6 IPv6 next hop we are forwarding to (out). 858 * args->f_id Addresses grabbed from the packet (out) 859 * args->rule.info a cookie depending on rule action 860 * 861 * Return value: 862 * 863 * IP_FW_PASS the packet must be accepted 864 * IP_FW_DENY the packet must be dropped 865 * IP_FW_DIVERT divert packet, port in m_tag 866 * IP_FW_TEE tee packet, port in m_tag 867 * IP_FW_DUMMYNET to dummynet, pipe in args->cookie 868 * IP_FW_NETGRAPH into netgraph, cookie args->cookie 869 * args->rule contains the matching rule, 870 * args->rule.info has additional information. 871 * 872 */ 873 int 874 ipfw_chk(struct ip_fw_args *args) 875 { 876 877 /* 878 * Local variables holding state while processing a packet: 879 * 880 * IMPORTANT NOTE: to speed up the processing of rules, there 881 * are some assumption on the values of the variables, which 882 * are documented here. Should you change them, please check 883 * the implementation of the various instructions to make sure 884 * that they still work. 885 * 886 * args->eh The MAC header. It is non-null for a layer2 887 * packet, it is NULL for a layer-3 packet. 888 * **notyet** 889 * args->L3offset Offset in the packet to the L3 (IP or equiv.) header. 890 * 891 * m | args->m Pointer to the mbuf, as received from the caller. 892 * It may change if ipfw_chk() does an m_pullup, or if it 893 * consumes the packet because it calls send_reject(). 894 * XXX This has to change, so that ipfw_chk() never modifies 895 * or consumes the buffer. 896 * ip is the beginning of the ip(4 or 6) header. 897 * Calculated by adding the L3offset to the start of data. 898 * (Until we start using L3offset, the packet is 899 * supposed to start with the ip header). 900 */ 901 struct mbuf *m = args->m; 902 struct ip *ip = mtod(m, struct ip *); 903 904 /* 905 * For rules which contain uid/gid or jail constraints, cache 906 * a copy of the users credentials after the pcb lookup has been 907 * executed. This will speed up the processing of rules with 908 * these types of constraints, as well as decrease contention 909 * on pcb related locks. 910 */ 911 #ifndef __FreeBSD__ 912 struct bsd_ucred ucred_cache; 913 #else 914 struct ucred *ucred_cache = NULL; 915 #endif 916 int ucred_lookup = 0; 917 918 /* 919 * oif | args->oif If NULL, ipfw_chk has been called on the 920 * inbound path (ether_input, ip_input). 921 * If non-NULL, ipfw_chk has been called on the outbound path 922 * (ether_output, ip_output). 923 */ 924 struct ifnet *oif = args->oif; 925 926 int f_pos = 0; /* index of current rule in the array */ 927 int retval = 0; 928 929 /* 930 * hlen The length of the IP header. 931 */ 932 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 933 934 /* 935 * offset The offset of a fragment. offset != 0 means that 936 * we have a fragment at this offset of an IPv4 packet. 937 * offset == 0 means that (if this is an IPv4 packet) 938 * this is the first or only fragment. 939 * For IPv6 offset|ip6f_mf == 0 means there is no Fragment Header 940 * or there is a single packet fragment (fragment header added 941 * without needed). We will treat a single packet fragment as if 942 * there was no fragment header (or log/block depending on the 943 * V_fw_permit_single_frag6 sysctl setting). 944 */ 945 u_short offset = 0; 946 u_short ip6f_mf = 0; 947 948 /* 949 * Local copies of addresses. They are only valid if we have 950 * an IP packet. 951 * 952 * proto The protocol. Set to 0 for non-ip packets, 953 * or to the protocol read from the packet otherwise. 954 * proto != 0 means that we have an IPv4 packet. 955 * 956 * src_port, dst_port port numbers, in HOST format. Only 957 * valid for TCP and UDP packets. 958 * 959 * src_ip, dst_ip ip addresses, in NETWORK format. 960 * Only valid for IPv4 packets. 961 */ 962 uint8_t proto; 963 uint16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 964 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 965 int iplen = 0; 966 int pktlen; 967 uint16_t etype = 0; /* Host order stored ether type */ 968 969 /* 970 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 971 * MATCH_NONE when checked and not matched (q = NULL), 972 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 973 */ 974 int dyn_dir = MATCH_UNKNOWN; 975 uint16_t dyn_name = 0; 976 ipfw_dyn_rule *q = NULL; 977 struct ip_fw_chain *chain = &V_layer3_chain; 978 979 /* 980 * We store in ulp a pointer to the upper layer protocol header. 981 * In the ipv4 case this is easy to determine from the header, 982 * but for ipv6 we might have some additional headers in the middle. 983 * ulp is NULL if not found. 984 */ 985 void *ulp = NULL; /* upper layer protocol pointer. */ 986 987 /* XXX ipv6 variables */ 988 int is_ipv6 = 0; 989 uint8_t icmp6_type = 0; 990 uint16_t ext_hd = 0; /* bits vector for extension header filtering */ 991 /* end of ipv6 variables */ 992 993 int is_ipv4 = 0; 994 995 int done = 0; /* flag to exit the outer loop */ 996 997 if (m->m_flags & M_SKIP_FIREWALL || (! V_ipfw_vnet_ready)) 998 return (IP_FW_PASS); /* accept */ 999 1000 dst_ip.s_addr = 0; /* make sure it is initialized */ 1001 src_ip.s_addr = 0; /* make sure it is initialized */ 1002 pktlen = m->m_pkthdr.len; 1003 args->f_id.fib = M_GETFIB(m); /* note mbuf not altered) */ 1004 proto = args->f_id.proto = 0; /* mark f_id invalid */ 1005 /* XXX 0 is a valid proto: IP/IPv6 Hop-by-Hop Option */ 1006 1007 /* 1008 * PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous, 1009 * then it sets p to point at the offset "len" in the mbuf. WARNING: the 1010 * pointer might become stale after other pullups (but we never use it 1011 * this way). 1012 */ 1013 #define PULLUP_TO(_len, p, T) PULLUP_LEN(_len, p, sizeof(T)) 1014 #define PULLUP_LEN(_len, p, T) \ 1015 do { \ 1016 int x = (_len) + T; \ 1017 if ((m)->m_len < x) { \ 1018 args->m = m = m_pullup(m, x); \ 1019 if (m == NULL) \ 1020 goto pullup_failed; \ 1021 } \ 1022 p = (mtod(m, char *) + (_len)); \ 1023 } while (0) 1024 1025 /* 1026 * if we have an ether header, 1027 */ 1028 if (args->eh) 1029 etype = ntohs(args->eh->ether_type); 1030 1031 /* Identify IP packets and fill up variables. */ 1032 if (pktlen >= sizeof(struct ip6_hdr) && 1033 (args->eh == NULL || etype == ETHERTYPE_IPV6) && ip->ip_v == 6) { 1034 struct ip6_hdr *ip6 = (struct ip6_hdr *)ip; 1035 is_ipv6 = 1; 1036 args->f_id.addr_type = 6; 1037 hlen = sizeof(struct ip6_hdr); 1038 proto = ip6->ip6_nxt; 1039 1040 /* Search extension headers to find upper layer protocols */ 1041 while (ulp == NULL && offset == 0) { 1042 switch (proto) { 1043 case IPPROTO_ICMPV6: 1044 PULLUP_TO(hlen, ulp, struct icmp6_hdr); 1045 icmp6_type = ICMP6(ulp)->icmp6_type; 1046 break; 1047 1048 case IPPROTO_TCP: 1049 PULLUP_TO(hlen, ulp, struct tcphdr); 1050 dst_port = TCP(ulp)->th_dport; 1051 src_port = TCP(ulp)->th_sport; 1052 /* save flags for dynamic rules */ 1053 args->f_id._flags = TCP(ulp)->th_flags; 1054 break; 1055 1056 case IPPROTO_SCTP: 1057 PULLUP_TO(hlen, ulp, struct sctphdr); 1058 src_port = SCTP(ulp)->src_port; 1059 dst_port = SCTP(ulp)->dest_port; 1060 break; 1061 1062 case IPPROTO_UDP: 1063 PULLUP_TO(hlen, ulp, struct udphdr); 1064 dst_port = UDP(ulp)->uh_dport; 1065 src_port = UDP(ulp)->uh_sport; 1066 break; 1067 1068 case IPPROTO_HOPOPTS: /* RFC 2460 */ 1069 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1070 ext_hd |= EXT_HOPOPTS; 1071 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1072 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1073 ulp = NULL; 1074 break; 1075 1076 case IPPROTO_ROUTING: /* RFC 2460 */ 1077 PULLUP_TO(hlen, ulp, struct ip6_rthdr); 1078 switch (((struct ip6_rthdr *)ulp)->ip6r_type) { 1079 case 0: 1080 ext_hd |= EXT_RTHDR0; 1081 break; 1082 case 2: 1083 ext_hd |= EXT_RTHDR2; 1084 break; 1085 default: 1086 if (V_fw_verbose) 1087 printf("IPFW2: IPV6 - Unknown " 1088 "Routing Header type(%d)\n", 1089 ((struct ip6_rthdr *) 1090 ulp)->ip6r_type); 1091 if (V_fw_deny_unknown_exthdrs) 1092 return (IP_FW_DENY); 1093 break; 1094 } 1095 ext_hd |= EXT_ROUTING; 1096 hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3; 1097 proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt; 1098 ulp = NULL; 1099 break; 1100 1101 case IPPROTO_FRAGMENT: /* RFC 2460 */ 1102 PULLUP_TO(hlen, ulp, struct ip6_frag); 1103 ext_hd |= EXT_FRAGMENT; 1104 hlen += sizeof (struct ip6_frag); 1105 proto = ((struct ip6_frag *)ulp)->ip6f_nxt; 1106 offset = ((struct ip6_frag *)ulp)->ip6f_offlg & 1107 IP6F_OFF_MASK; 1108 ip6f_mf = ((struct ip6_frag *)ulp)->ip6f_offlg & 1109 IP6F_MORE_FRAG; 1110 if (V_fw_permit_single_frag6 == 0 && 1111 offset == 0 && ip6f_mf == 0) { 1112 if (V_fw_verbose) 1113 printf("IPFW2: IPV6 - Invalid " 1114 "Fragment Header\n"); 1115 if (V_fw_deny_unknown_exthdrs) 1116 return (IP_FW_DENY); 1117 break; 1118 } 1119 args->f_id.extra = 1120 ntohl(((struct ip6_frag *)ulp)->ip6f_ident); 1121 ulp = NULL; 1122 break; 1123 1124 case IPPROTO_DSTOPTS: /* RFC 2460 */ 1125 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1126 ext_hd |= EXT_DSTOPTS; 1127 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1128 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1129 ulp = NULL; 1130 break; 1131 1132 case IPPROTO_AH: /* RFC 2402 */ 1133 PULLUP_TO(hlen, ulp, struct ip6_ext); 1134 ext_hd |= EXT_AH; 1135 hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2; 1136 proto = ((struct ip6_ext *)ulp)->ip6e_nxt; 1137 ulp = NULL; 1138 break; 1139 1140 case IPPROTO_ESP: /* RFC 2406 */ 1141 PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */ 1142 /* Anything past Seq# is variable length and 1143 * data past this ext. header is encrypted. */ 1144 ext_hd |= EXT_ESP; 1145 break; 1146 1147 case IPPROTO_NONE: /* RFC 2460 */ 1148 /* 1149 * Packet ends here, and IPv6 header has 1150 * already been pulled up. If ip6e_len!=0 1151 * then octets must be ignored. 1152 */ 1153 ulp = ip; /* non-NULL to get out of loop. */ 1154 break; 1155 1156 case IPPROTO_OSPFIGP: 1157 /* XXX OSPF header check? */ 1158 PULLUP_TO(hlen, ulp, struct ip6_ext); 1159 break; 1160 1161 case IPPROTO_PIM: 1162 /* XXX PIM header check? */ 1163 PULLUP_TO(hlen, ulp, struct pim); 1164 break; 1165 1166 case IPPROTO_GRE: /* RFC 1701 */ 1167 /* XXX GRE header check? */ 1168 PULLUP_TO(hlen, ulp, struct grehdr); 1169 break; 1170 1171 case IPPROTO_CARP: 1172 PULLUP_TO(hlen, ulp, struct carp_header); 1173 if (((struct carp_header *)ulp)->carp_version != 1174 CARP_VERSION) 1175 return (IP_FW_DENY); 1176 if (((struct carp_header *)ulp)->carp_type != 1177 CARP_ADVERTISEMENT) 1178 return (IP_FW_DENY); 1179 break; 1180 1181 case IPPROTO_IPV6: /* RFC 2893 */ 1182 PULLUP_TO(hlen, ulp, struct ip6_hdr); 1183 break; 1184 1185 case IPPROTO_IPV4: /* RFC 2893 */ 1186 PULLUP_TO(hlen, ulp, struct ip); 1187 break; 1188 1189 default: 1190 if (V_fw_verbose) 1191 printf("IPFW2: IPV6 - Unknown " 1192 "Extension Header(%d), ext_hd=%x\n", 1193 proto, ext_hd); 1194 if (V_fw_deny_unknown_exthdrs) 1195 return (IP_FW_DENY); 1196 PULLUP_TO(hlen, ulp, struct ip6_ext); 1197 break; 1198 } /*switch */ 1199 } 1200 ip = mtod(m, struct ip *); 1201 ip6 = (struct ip6_hdr *)ip; 1202 args->f_id.src_ip6 = ip6->ip6_src; 1203 args->f_id.dst_ip6 = ip6->ip6_dst; 1204 args->f_id.src_ip = 0; 1205 args->f_id.dst_ip = 0; 1206 args->f_id.flow_id6 = ntohl(ip6->ip6_flow); 1207 iplen = ntohs(ip6->ip6_plen) + sizeof(*ip6); 1208 } else if (pktlen >= sizeof(struct ip) && 1209 (args->eh == NULL || etype == ETHERTYPE_IP) && ip->ip_v == 4) { 1210 is_ipv4 = 1; 1211 hlen = ip->ip_hl << 2; 1212 args->f_id.addr_type = 4; 1213 1214 /* 1215 * Collect parameters into local variables for faster matching. 1216 */ 1217 proto = ip->ip_p; 1218 src_ip = ip->ip_src; 1219 dst_ip = ip->ip_dst; 1220 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1221 iplen = ntohs(ip->ip_len); 1222 1223 if (offset == 0) { 1224 switch (proto) { 1225 case IPPROTO_TCP: 1226 PULLUP_TO(hlen, ulp, struct tcphdr); 1227 dst_port = TCP(ulp)->th_dport; 1228 src_port = TCP(ulp)->th_sport; 1229 /* save flags for dynamic rules */ 1230 args->f_id._flags = TCP(ulp)->th_flags; 1231 break; 1232 1233 case IPPROTO_SCTP: 1234 PULLUP_TO(hlen, ulp, struct sctphdr); 1235 src_port = SCTP(ulp)->src_port; 1236 dst_port = SCTP(ulp)->dest_port; 1237 break; 1238 1239 case IPPROTO_UDP: 1240 PULLUP_TO(hlen, ulp, struct udphdr); 1241 dst_port = UDP(ulp)->uh_dport; 1242 src_port = UDP(ulp)->uh_sport; 1243 break; 1244 1245 case IPPROTO_ICMP: 1246 PULLUP_TO(hlen, ulp, struct icmphdr); 1247 //args->f_id.flags = ICMP(ulp)->icmp_type; 1248 break; 1249 1250 default: 1251 break; 1252 } 1253 } 1254 1255 ip = mtod(m, struct ip *); 1256 args->f_id.src_ip = ntohl(src_ip.s_addr); 1257 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1258 } 1259 #undef PULLUP_TO 1260 pktlen = iplen < pktlen ? iplen: pktlen; 1261 if (proto) { /* we may have port numbers, store them */ 1262 args->f_id.proto = proto; 1263 args->f_id.src_port = src_port = ntohs(src_port); 1264 args->f_id.dst_port = dst_port = ntohs(dst_port); 1265 } 1266 1267 IPFW_PF_RLOCK(chain); 1268 if (! V_ipfw_vnet_ready) { /* shutting down, leave NOW. */ 1269 IPFW_PF_RUNLOCK(chain); 1270 return (IP_FW_PASS); /* accept */ 1271 } 1272 if (args->rule.slot) { 1273 /* 1274 * Packet has already been tagged as a result of a previous 1275 * match on rule args->rule aka args->rule_id (PIPE, QUEUE, 1276 * REASS, NETGRAPH, DIVERT/TEE...) 1277 * Validate the slot and continue from the next one 1278 * if still present, otherwise do a lookup. 1279 */ 1280 f_pos = (args->rule.chain_id == chain->id) ? 1281 args->rule.slot : 1282 ipfw_find_rule(chain, args->rule.rulenum, 1283 args->rule.rule_id); 1284 } else { 1285 f_pos = 0; 1286 } 1287 1288 /* 1289 * Now scan the rules, and parse microinstructions for each rule. 1290 * We have two nested loops and an inner switch. Sometimes we 1291 * need to break out of one or both loops, or re-enter one of 1292 * the loops with updated variables. Loop variables are: 1293 * 1294 * f_pos (outer loop) points to the current rule. 1295 * On output it points to the matching rule. 1296 * done (outer loop) is used as a flag to break the loop. 1297 * l (inner loop) residual length of current rule. 1298 * cmd points to the current microinstruction. 1299 * 1300 * We break the inner loop by setting l=0 and possibly 1301 * cmdlen=0 if we don't want to advance cmd. 1302 * We break the outer loop by setting done=1 1303 * We can restart the inner loop by setting l>0 and f_pos, f, cmd 1304 * as needed. 1305 */ 1306 for (; f_pos < chain->n_rules; f_pos++) { 1307 ipfw_insn *cmd; 1308 uint32_t tablearg = 0; 1309 int l, cmdlen, skip_or; /* skip rest of OR block */ 1310 struct ip_fw *f; 1311 1312 f = chain->map[f_pos]; 1313 if (V_set_disable & (1 << f->set) ) 1314 continue; 1315 1316 skip_or = 0; 1317 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1318 l -= cmdlen, cmd += cmdlen) { 1319 int match; 1320 1321 /* 1322 * check_body is a jump target used when we find a 1323 * CHECK_STATE, and need to jump to the body of 1324 * the target rule. 1325 */ 1326 1327 /* check_body: */ 1328 cmdlen = F_LEN(cmd); 1329 /* 1330 * An OR block (insn_1 || .. || insn_n) has the 1331 * F_OR bit set in all but the last instruction. 1332 * The first match will set "skip_or", and cause 1333 * the following instructions to be skipped until 1334 * past the one with the F_OR bit clear. 1335 */ 1336 if (skip_or) { /* skip this instruction */ 1337 if ((cmd->len & F_OR) == 0) 1338 skip_or = 0; /* next one is good */ 1339 continue; 1340 } 1341 match = 0; /* set to 1 if we succeed */ 1342 1343 switch (cmd->opcode) { 1344 /* 1345 * The first set of opcodes compares the packet's 1346 * fields with some pattern, setting 'match' if a 1347 * match is found. At the end of the loop there is 1348 * logic to deal with F_NOT and F_OR flags associated 1349 * with the opcode. 1350 */ 1351 case O_NOP: 1352 match = 1; 1353 break; 1354 1355 case O_FORWARD_MAC: 1356 printf("ipfw: opcode %d unimplemented\n", 1357 cmd->opcode); 1358 break; 1359 1360 case O_GID: 1361 case O_UID: 1362 case O_JAIL: 1363 /* 1364 * We only check offset == 0 && proto != 0, 1365 * as this ensures that we have a 1366 * packet with the ports info. 1367 */ 1368 if (offset != 0) 1369 break; 1370 if (proto == IPPROTO_TCP || 1371 proto == IPPROTO_UDP) 1372 match = check_uidgid( 1373 (ipfw_insn_u32 *)cmd, 1374 args, &ucred_lookup, 1375 #ifdef __FreeBSD__ 1376 &ucred_cache); 1377 #else 1378 (void *)&ucred_cache); 1379 #endif 1380 break; 1381 1382 case O_RECV: 1383 match = iface_match(m->m_pkthdr.rcvif, 1384 (ipfw_insn_if *)cmd, chain, &tablearg); 1385 break; 1386 1387 case O_XMIT: 1388 match = iface_match(oif, (ipfw_insn_if *)cmd, 1389 chain, &tablearg); 1390 break; 1391 1392 case O_VIA: 1393 match = iface_match(oif ? oif : 1394 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd, 1395 chain, &tablearg); 1396 break; 1397 1398 case O_MACADDR2: 1399 if (args->eh != NULL) { /* have MAC header */ 1400 u_int32_t *want = (u_int32_t *) 1401 ((ipfw_insn_mac *)cmd)->addr; 1402 u_int32_t *mask = (u_int32_t *) 1403 ((ipfw_insn_mac *)cmd)->mask; 1404 u_int32_t *hdr = (u_int32_t *)args->eh; 1405 1406 match = 1407 ( want[0] == (hdr[0] & mask[0]) && 1408 want[1] == (hdr[1] & mask[1]) && 1409 want[2] == (hdr[2] & mask[2]) ); 1410 } 1411 break; 1412 1413 case O_MAC_TYPE: 1414 if (args->eh != NULL) { 1415 u_int16_t *p = 1416 ((ipfw_insn_u16 *)cmd)->ports; 1417 int i; 1418 1419 for (i = cmdlen - 1; !match && i>0; 1420 i--, p += 2) 1421 match = (etype >= p[0] && 1422 etype <= p[1]); 1423 } 1424 break; 1425 1426 case O_FRAG: 1427 match = (offset != 0); 1428 break; 1429 1430 case O_IN: /* "out" is "not in" */ 1431 match = (oif == NULL); 1432 break; 1433 1434 case O_LAYER2: 1435 match = (args->eh != NULL); 1436 break; 1437 1438 case O_DIVERTED: 1439 { 1440 /* For diverted packets, args->rule.info 1441 * contains the divert port (in host format) 1442 * reason and direction. 1443 */ 1444 uint32_t i = args->rule.info; 1445 match = (i&IPFW_IS_MASK) == IPFW_IS_DIVERT && 1446 cmd->arg1 & ((i & IPFW_INFO_IN) ? 1 : 2); 1447 } 1448 break; 1449 1450 case O_PROTO: 1451 /* 1452 * We do not allow an arg of 0 so the 1453 * check of "proto" only suffices. 1454 */ 1455 match = (proto == cmd->arg1); 1456 break; 1457 1458 case O_IP_SRC: 1459 match = is_ipv4 && 1460 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1461 src_ip.s_addr); 1462 break; 1463 1464 case O_IP_DST_LOOKUP: 1465 { 1466 void *pkey; 1467 uint32_t vidx, key; 1468 uint16_t keylen; 1469 1470 if (cmdlen > F_INSN_SIZE(ipfw_insn_u32)) { 1471 /* Determine lookup key type */ 1472 vidx = ((ipfw_insn_u32 *)cmd)->d[1]; 1473 if (vidx != 4 /* uid */ && 1474 vidx != 5 /* jail */ && 1475 is_ipv6 == 0 && is_ipv4 == 0) 1476 break; 1477 /* Determine key length */ 1478 if (vidx == 0 /* dst-ip */ || 1479 vidx == 1 /* src-ip */) 1480 keylen = is_ipv6 ? 1481 sizeof(struct in6_addr): 1482 sizeof(in_addr_t); 1483 else { 1484 keylen = sizeof(key); 1485 pkey = &key; 1486 } 1487 if (vidx == 0 /* dst-ip */) 1488 pkey = is_ipv4 ? (void *)&dst_ip: 1489 (void *)&args->f_id.dst_ip6; 1490 else if (vidx == 1 /* src-ip */) 1491 pkey = is_ipv4 ? (void *)&src_ip: 1492 (void *)&args->f_id.src_ip6; 1493 else if (vidx == 6 /* dscp */) { 1494 if (is_ipv4) 1495 key = ip->ip_tos >> 2; 1496 else { 1497 key = args->f_id.flow_id6; 1498 key = (key & 0x0f) << 2 | 1499 (key & 0xf000) >> 14; 1500 } 1501 key &= 0x3f; 1502 } else if (vidx == 2 /* dst-port */ || 1503 vidx == 3 /* src-port */) { 1504 /* Skip fragments */ 1505 if (offset != 0) 1506 break; 1507 /* Skip proto without ports */ 1508 if (proto != IPPROTO_TCP && 1509 proto != IPPROTO_UDP && 1510 proto != IPPROTO_SCTP) 1511 break; 1512 if (vidx == 2 /* dst-port */) 1513 key = dst_port; 1514 else 1515 key = src_port; 1516 } 1517 #ifndef USERSPACE 1518 else if (vidx == 4 /* uid */ || 1519 vidx == 5 /* jail */) { 1520 check_uidgid( 1521 (ipfw_insn_u32 *)cmd, 1522 args, &ucred_lookup, 1523 #ifdef __FreeBSD__ 1524 &ucred_cache); 1525 if (vidx == 4 /* uid */) 1526 key = ucred_cache->cr_uid; 1527 else if (vidx == 5 /* jail */) 1528 key = ucred_cache->cr_prison->pr_id; 1529 #else /* !__FreeBSD__ */ 1530 (void *)&ucred_cache); 1531 if (vidx == 4 /* uid */) 1532 key = ucred_cache.uid; 1533 else if (vidx == 5 /* jail */) 1534 key = ucred_cache.xid; 1535 #endif /* !__FreeBSD__ */ 1536 } 1537 #endif /* !USERSPACE */ 1538 else 1539 break; 1540 match = ipfw_lookup_table(chain, 1541 cmd->arg1, keylen, pkey, &vidx); 1542 if (!match) 1543 break; 1544 tablearg = vidx; 1545 break; 1546 } 1547 /* cmdlen =< F_INSN_SIZE(ipfw_insn_u32) */ 1548 /* FALLTHROUGH */ 1549 } 1550 case O_IP_SRC_LOOKUP: 1551 { 1552 void *pkey; 1553 uint32_t vidx; 1554 uint16_t keylen; 1555 1556 if (is_ipv4) { 1557 keylen = sizeof(in_addr_t); 1558 if (cmd->opcode == O_IP_DST_LOOKUP) 1559 pkey = &dst_ip; 1560 else 1561 pkey = &src_ip; 1562 } else if (is_ipv6) { 1563 keylen = sizeof(struct in6_addr); 1564 if (cmd->opcode == O_IP_DST_LOOKUP) 1565 pkey = &args->f_id.dst_ip6; 1566 else 1567 pkey = &args->f_id.src_ip6; 1568 } else 1569 break; 1570 match = ipfw_lookup_table(chain, cmd->arg1, 1571 keylen, pkey, &vidx); 1572 if (!match) 1573 break; 1574 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) { 1575 match = ((ipfw_insn_u32 *)cmd)->d[0] == 1576 TARG_VAL(chain, vidx, tag); 1577 if (!match) 1578 break; 1579 } 1580 tablearg = vidx; 1581 break; 1582 } 1583 1584 case O_IP_FLOW_LOOKUP: 1585 { 1586 uint32_t v = 0; 1587 match = ipfw_lookup_table(chain, 1588 cmd->arg1, 0, &args->f_id, &v); 1589 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 1590 match = ((ipfw_insn_u32 *)cmd)->d[0] == 1591 TARG_VAL(chain, v, tag); 1592 if (match) 1593 tablearg = v; 1594 } 1595 break; 1596 case O_IP_SRC_MASK: 1597 case O_IP_DST_MASK: 1598 if (is_ipv4) { 1599 uint32_t a = 1600 (cmd->opcode == O_IP_DST_MASK) ? 1601 dst_ip.s_addr : src_ip.s_addr; 1602 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 1603 int i = cmdlen-1; 1604 1605 for (; !match && i>0; i-= 2, p+= 2) 1606 match = (p[0] == (a & p[1])); 1607 } 1608 break; 1609 1610 case O_IP_SRC_ME: 1611 if (is_ipv4) { 1612 match = in_localip(src_ip); 1613 break; 1614 } 1615 #ifdef INET6 1616 /* FALLTHROUGH */ 1617 case O_IP6_SRC_ME: 1618 match= is_ipv6 && ipfw_localip6(&args->f_id.src_ip6); 1619 #endif 1620 break; 1621 1622 case O_IP_DST_SET: 1623 case O_IP_SRC_SET: 1624 if (is_ipv4) { 1625 u_int32_t *d = (u_int32_t *)(cmd+1); 1626 u_int32_t addr = 1627 cmd->opcode == O_IP_DST_SET ? 1628 args->f_id.dst_ip : 1629 args->f_id.src_ip; 1630 1631 if (addr < d[0]) 1632 break; 1633 addr -= d[0]; /* subtract base */ 1634 match = (addr < cmd->arg1) && 1635 ( d[ 1 + (addr>>5)] & 1636 (1<<(addr & 0x1f)) ); 1637 } 1638 break; 1639 1640 case O_IP_DST: 1641 match = is_ipv4 && 1642 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1643 dst_ip.s_addr); 1644 break; 1645 1646 case O_IP_DST_ME: 1647 if (is_ipv4) { 1648 match = in_localip(dst_ip); 1649 break; 1650 } 1651 #ifdef INET6 1652 /* FALLTHROUGH */ 1653 case O_IP6_DST_ME: 1654 match= is_ipv6 && ipfw_localip6(&args->f_id.dst_ip6); 1655 #endif 1656 break; 1657 1658 1659 case O_IP_SRCPORT: 1660 case O_IP_DSTPORT: 1661 /* 1662 * offset == 0 && proto != 0 is enough 1663 * to guarantee that we have a 1664 * packet with port info. 1665 */ 1666 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP || 1667 proto==IPPROTO_SCTP) && offset == 0) { 1668 u_int16_t x = 1669 (cmd->opcode == O_IP_SRCPORT) ? 1670 src_port : dst_port ; 1671 u_int16_t *p = 1672 ((ipfw_insn_u16 *)cmd)->ports; 1673 int i; 1674 1675 for (i = cmdlen - 1; !match && i>0; 1676 i--, p += 2) 1677 match = (x>=p[0] && x<=p[1]); 1678 } 1679 break; 1680 1681 case O_ICMPTYPE: 1682 match = (offset == 0 && proto==IPPROTO_ICMP && 1683 icmptype_match(ICMP(ulp), (ipfw_insn_u32 *)cmd) ); 1684 break; 1685 1686 #ifdef INET6 1687 case O_ICMP6TYPE: 1688 match = is_ipv6 && offset == 0 && 1689 proto==IPPROTO_ICMPV6 && 1690 icmp6type_match( 1691 ICMP6(ulp)->icmp6_type, 1692 (ipfw_insn_u32 *)cmd); 1693 break; 1694 #endif /* INET6 */ 1695 1696 case O_IPOPT: 1697 match = (is_ipv4 && 1698 ipopts_match(ip, cmd) ); 1699 break; 1700 1701 case O_IPVER: 1702 match = (is_ipv4 && 1703 cmd->arg1 == ip->ip_v); 1704 break; 1705 1706 case O_IPID: 1707 case O_IPLEN: 1708 case O_IPTTL: 1709 if (is_ipv4) { /* only for IP packets */ 1710 uint16_t x; 1711 uint16_t *p; 1712 int i; 1713 1714 if (cmd->opcode == O_IPLEN) 1715 x = iplen; 1716 else if (cmd->opcode == O_IPTTL) 1717 x = ip->ip_ttl; 1718 else /* must be IPID */ 1719 x = ntohs(ip->ip_id); 1720 if (cmdlen == 1) { 1721 match = (cmd->arg1 == x); 1722 break; 1723 } 1724 /* otherwise we have ranges */ 1725 p = ((ipfw_insn_u16 *)cmd)->ports; 1726 i = cmdlen - 1; 1727 for (; !match && i>0; i--, p += 2) 1728 match = (x >= p[0] && x <= p[1]); 1729 } 1730 break; 1731 1732 case O_IPPRECEDENCE: 1733 match = (is_ipv4 && 1734 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 1735 break; 1736 1737 case O_IPTOS: 1738 match = (is_ipv4 && 1739 flags_match(cmd, ip->ip_tos)); 1740 break; 1741 1742 case O_DSCP: 1743 { 1744 uint32_t *p; 1745 uint16_t x; 1746 1747 p = ((ipfw_insn_u32 *)cmd)->d; 1748 1749 if (is_ipv4) 1750 x = ip->ip_tos >> 2; 1751 else if (is_ipv6) { 1752 uint8_t *v; 1753 v = &((struct ip6_hdr *)ip)->ip6_vfc; 1754 x = (*v & 0x0F) << 2; 1755 v++; 1756 x |= *v >> 6; 1757 } else 1758 break; 1759 1760 /* DSCP bitmask is stored as low_u32 high_u32 */ 1761 if (x >= 32) 1762 match = *(p + 1) & (1 << (x - 32)); 1763 else 1764 match = *p & (1 << x); 1765 } 1766 break; 1767 1768 case O_TCPDATALEN: 1769 if (proto == IPPROTO_TCP && offset == 0) { 1770 struct tcphdr *tcp; 1771 uint16_t x; 1772 uint16_t *p; 1773 int i; 1774 #ifdef INET6 1775 if (is_ipv6) { 1776 struct ip6_hdr *ip6; 1777 1778 ip6 = (struct ip6_hdr *)ip; 1779 if (ip6->ip6_plen == 0) { 1780 /* 1781 * Jumbo payload is not 1782 * supported by this 1783 * opcode. 1784 */ 1785 break; 1786 } 1787 x = iplen - hlen; 1788 } else 1789 #endif /* INET6 */ 1790 x = iplen - (ip->ip_hl << 2); 1791 tcp = TCP(ulp); 1792 x -= tcp->th_off << 2; 1793 if (cmdlen == 1) { 1794 match = (cmd->arg1 == x); 1795 break; 1796 } 1797 /* otherwise we have ranges */ 1798 p = ((ipfw_insn_u16 *)cmd)->ports; 1799 i = cmdlen - 1; 1800 for (; !match && i>0; i--, p += 2) 1801 match = (x >= p[0] && x <= p[1]); 1802 } 1803 break; 1804 1805 case O_TCPFLAGS: 1806 match = (proto == IPPROTO_TCP && offset == 0 && 1807 flags_match(cmd, TCP(ulp)->th_flags)); 1808 break; 1809 1810 case O_TCPOPTS: 1811 if (proto == IPPROTO_TCP && offset == 0 && ulp){ 1812 PULLUP_LEN(hlen, ulp, 1813 (TCP(ulp)->th_off << 2)); 1814 match = tcpopts_match(TCP(ulp), cmd); 1815 } 1816 break; 1817 1818 case O_TCPSEQ: 1819 match = (proto == IPPROTO_TCP && offset == 0 && 1820 ((ipfw_insn_u32 *)cmd)->d[0] == 1821 TCP(ulp)->th_seq); 1822 break; 1823 1824 case O_TCPACK: 1825 match = (proto == IPPROTO_TCP && offset == 0 && 1826 ((ipfw_insn_u32 *)cmd)->d[0] == 1827 TCP(ulp)->th_ack); 1828 break; 1829 1830 case O_TCPWIN: 1831 if (proto == IPPROTO_TCP && offset == 0) { 1832 uint16_t x; 1833 uint16_t *p; 1834 int i; 1835 1836 x = ntohs(TCP(ulp)->th_win); 1837 if (cmdlen == 1) { 1838 match = (cmd->arg1 == x); 1839 break; 1840 } 1841 /* Otherwise we have ranges. */ 1842 p = ((ipfw_insn_u16 *)cmd)->ports; 1843 i = cmdlen - 1; 1844 for (; !match && i > 0; i--, p += 2) 1845 match = (x >= p[0] && x <= p[1]); 1846 } 1847 break; 1848 1849 case O_ESTAB: 1850 /* reject packets which have SYN only */ 1851 /* XXX should i also check for TH_ACK ? */ 1852 match = (proto == IPPROTO_TCP && offset == 0 && 1853 (TCP(ulp)->th_flags & 1854 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 1855 break; 1856 1857 case O_ALTQ: { 1858 struct pf_mtag *at; 1859 struct m_tag *mtag; 1860 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 1861 1862 /* 1863 * ALTQ uses mbuf tags from another 1864 * packet filtering system - pf(4). 1865 * We allocate a tag in its format 1866 * and fill it in, pretending to be pf(4). 1867 */ 1868 match = 1; 1869 at = pf_find_mtag(m); 1870 if (at != NULL && at->qid != 0) 1871 break; 1872 mtag = m_tag_get(PACKET_TAG_PF, 1873 sizeof(struct pf_mtag), M_NOWAIT | M_ZERO); 1874 if (mtag == NULL) { 1875 /* 1876 * Let the packet fall back to the 1877 * default ALTQ. 1878 */ 1879 break; 1880 } 1881 m_tag_prepend(m, mtag); 1882 at = (struct pf_mtag *)(mtag + 1); 1883 at->qid = altq->qid; 1884 at->hdr = ip; 1885 break; 1886 } 1887 1888 case O_LOG: 1889 ipfw_log(chain, f, hlen, args, m, 1890 oif, offset | ip6f_mf, tablearg, ip); 1891 match = 1; 1892 break; 1893 1894 case O_PROB: 1895 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 1896 break; 1897 1898 case O_VERREVPATH: 1899 /* Outgoing packets automatically pass/match */ 1900 match = ((oif != NULL) || 1901 (m->m_pkthdr.rcvif == NULL) || 1902 ( 1903 #ifdef INET6 1904 is_ipv6 ? 1905 verify_path6(&(args->f_id.src_ip6), 1906 m->m_pkthdr.rcvif, args->f_id.fib) : 1907 #endif 1908 verify_path(src_ip, m->m_pkthdr.rcvif, 1909 args->f_id.fib))); 1910 break; 1911 1912 case O_VERSRCREACH: 1913 /* Outgoing packets automatically pass/match */ 1914 match = (hlen > 0 && ((oif != NULL) || 1915 #ifdef INET6 1916 is_ipv6 ? 1917 verify_path6(&(args->f_id.src_ip6), 1918 NULL, args->f_id.fib) : 1919 #endif 1920 verify_path(src_ip, NULL, args->f_id.fib))); 1921 break; 1922 1923 case O_ANTISPOOF: 1924 /* Outgoing packets automatically pass/match */ 1925 if (oif == NULL && hlen > 0 && 1926 ( (is_ipv4 && in_localaddr(src_ip)) 1927 #ifdef INET6 1928 || (is_ipv6 && 1929 in6_localaddr(&(args->f_id.src_ip6))) 1930 #endif 1931 )) 1932 match = 1933 #ifdef INET6 1934 is_ipv6 ? verify_path6( 1935 &(args->f_id.src_ip6), 1936 m->m_pkthdr.rcvif, 1937 args->f_id.fib) : 1938 #endif 1939 verify_path(src_ip, 1940 m->m_pkthdr.rcvif, 1941 args->f_id.fib); 1942 else 1943 match = 1; 1944 break; 1945 1946 case O_IPSEC: 1947 match = (m_tag_find(m, 1948 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 1949 /* otherwise no match */ 1950 break; 1951 1952 #ifdef INET6 1953 case O_IP6_SRC: 1954 match = is_ipv6 && 1955 IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6, 1956 &((ipfw_insn_ip6 *)cmd)->addr6); 1957 break; 1958 1959 case O_IP6_DST: 1960 match = is_ipv6 && 1961 IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6, 1962 &((ipfw_insn_ip6 *)cmd)->addr6); 1963 break; 1964 case O_IP6_SRC_MASK: 1965 case O_IP6_DST_MASK: 1966 if (is_ipv6) { 1967 int i = cmdlen - 1; 1968 struct in6_addr p; 1969 struct in6_addr *d = 1970 &((ipfw_insn_ip6 *)cmd)->addr6; 1971 1972 for (; !match && i > 0; d += 2, 1973 i -= F_INSN_SIZE(struct in6_addr) 1974 * 2) { 1975 p = (cmd->opcode == 1976 O_IP6_SRC_MASK) ? 1977 args->f_id.src_ip6: 1978 args->f_id.dst_ip6; 1979 APPLY_MASK(&p, &d[1]); 1980 match = 1981 IN6_ARE_ADDR_EQUAL(&d[0], 1982 &p); 1983 } 1984 } 1985 break; 1986 1987 case O_FLOW6ID: 1988 match = is_ipv6 && 1989 flow6id_match(args->f_id.flow_id6, 1990 (ipfw_insn_u32 *) cmd); 1991 break; 1992 1993 case O_EXT_HDR: 1994 match = is_ipv6 && 1995 (ext_hd & ((ipfw_insn *) cmd)->arg1); 1996 break; 1997 1998 case O_IP6: 1999 match = is_ipv6; 2000 break; 2001 #endif 2002 2003 case O_IP4: 2004 match = is_ipv4; 2005 break; 2006 2007 case O_TAG: { 2008 struct m_tag *mtag; 2009 uint32_t tag = TARG(cmd->arg1, tag); 2010 2011 /* Packet is already tagged with this tag? */ 2012 mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL); 2013 2014 /* We have `untag' action when F_NOT flag is 2015 * present. And we must remove this mtag from 2016 * mbuf and reset `match' to zero (`match' will 2017 * be inversed later). 2018 * Otherwise we should allocate new mtag and 2019 * push it into mbuf. 2020 */ 2021 if (cmd->len & F_NOT) { /* `untag' action */ 2022 if (mtag != NULL) 2023 m_tag_delete(m, mtag); 2024 match = 0; 2025 } else { 2026 if (mtag == NULL) { 2027 mtag = m_tag_alloc( MTAG_IPFW, 2028 tag, 0, M_NOWAIT); 2029 if (mtag != NULL) 2030 m_tag_prepend(m, mtag); 2031 } 2032 match = 1; 2033 } 2034 break; 2035 } 2036 2037 case O_FIB: /* try match the specified fib */ 2038 if (args->f_id.fib == cmd->arg1) 2039 match = 1; 2040 break; 2041 2042 case O_SOCKARG: { 2043 #ifndef USERSPACE /* not supported in userspace */ 2044 struct inpcb *inp = args->inp; 2045 struct inpcbinfo *pi; 2046 2047 if (is_ipv6) /* XXX can we remove this ? */ 2048 break; 2049 2050 if (proto == IPPROTO_TCP) 2051 pi = &V_tcbinfo; 2052 else if (proto == IPPROTO_UDP) 2053 pi = &V_udbinfo; 2054 else 2055 break; 2056 2057 /* 2058 * XXXRW: so_user_cookie should almost 2059 * certainly be inp_user_cookie? 2060 */ 2061 2062 /* For incoming packet, lookup up the 2063 inpcb using the src/dest ip/port tuple */ 2064 if (inp == NULL) { 2065 inp = in_pcblookup(pi, 2066 src_ip, htons(src_port), 2067 dst_ip, htons(dst_port), 2068 INPLOOKUP_RLOCKPCB, NULL); 2069 if (inp != NULL) { 2070 tablearg = 2071 inp->inp_socket->so_user_cookie; 2072 if (tablearg) 2073 match = 1; 2074 INP_RUNLOCK(inp); 2075 } 2076 } else { 2077 if (inp->inp_socket) { 2078 tablearg = 2079 inp->inp_socket->so_user_cookie; 2080 if (tablearg) 2081 match = 1; 2082 } 2083 } 2084 #endif /* !USERSPACE */ 2085 break; 2086 } 2087 2088 case O_TAGGED: { 2089 struct m_tag *mtag; 2090 uint32_t tag = TARG(cmd->arg1, tag); 2091 2092 if (cmdlen == 1) { 2093 match = m_tag_locate(m, MTAG_IPFW, 2094 tag, NULL) != NULL; 2095 break; 2096 } 2097 2098 /* we have ranges */ 2099 for (mtag = m_tag_first(m); 2100 mtag != NULL && !match; 2101 mtag = m_tag_next(m, mtag)) { 2102 uint16_t *p; 2103 int i; 2104 2105 if (mtag->m_tag_cookie != MTAG_IPFW) 2106 continue; 2107 2108 p = ((ipfw_insn_u16 *)cmd)->ports; 2109 i = cmdlen - 1; 2110 for(; !match && i > 0; i--, p += 2) 2111 match = 2112 mtag->m_tag_id >= p[0] && 2113 mtag->m_tag_id <= p[1]; 2114 } 2115 break; 2116 } 2117 2118 /* 2119 * The second set of opcodes represents 'actions', 2120 * i.e. the terminal part of a rule once the packet 2121 * matches all previous patterns. 2122 * Typically there is only one action for each rule, 2123 * and the opcode is stored at the end of the rule 2124 * (but there are exceptions -- see below). 2125 * 2126 * In general, here we set retval and terminate the 2127 * outer loop (would be a 'break 3' in some language, 2128 * but we need to set l=0, done=1) 2129 * 2130 * Exceptions: 2131 * O_COUNT and O_SKIPTO actions: 2132 * instead of terminating, we jump to the next rule 2133 * (setting l=0), or to the SKIPTO target (setting 2134 * f/f_len, cmd and l as needed), respectively. 2135 * 2136 * O_TAG, O_LOG and O_ALTQ action parameters: 2137 * perform some action and set match = 1; 2138 * 2139 * O_LIMIT and O_KEEP_STATE: these opcodes are 2140 * not real 'actions', and are stored right 2141 * before the 'action' part of the rule. 2142 * These opcodes try to install an entry in the 2143 * state tables; if successful, we continue with 2144 * the next opcode (match=1; break;), otherwise 2145 * the packet must be dropped (set retval, 2146 * break loops with l=0, done=1) 2147 * 2148 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 2149 * cause a lookup of the state table, and a jump 2150 * to the 'action' part of the parent rule 2151 * if an entry is found, or 2152 * (CHECK_STATE only) a jump to the next rule if 2153 * the entry is not found. 2154 * The result of the lookup is cached so that 2155 * further instances of these opcodes become NOPs. 2156 * The jump to the next rule is done by setting 2157 * l=0, cmdlen=0. 2158 */ 2159 case O_LIMIT: 2160 case O_KEEP_STATE: 2161 if (ipfw_install_state(chain, f, 2162 (ipfw_insn_limit *)cmd, args, tablearg)) { 2163 /* error or limit violation */ 2164 retval = IP_FW_DENY; 2165 l = 0; /* exit inner loop */ 2166 done = 1; /* exit outer loop */ 2167 } 2168 match = 1; 2169 break; 2170 2171 case O_PROBE_STATE: 2172 case O_CHECK_STATE: 2173 /* 2174 * dynamic rules are checked at the first 2175 * keep-state or check-state occurrence, 2176 * with the result being stored in dyn_dir 2177 * and dyn_name. 2178 * The compiler introduces a PROBE_STATE 2179 * instruction for us when we have a 2180 * KEEP_STATE (because PROBE_STATE needs 2181 * to be run first). 2182 * 2183 * (dyn_dir == MATCH_UNKNOWN) means this is 2184 * first lookup for such f_id. Do lookup. 2185 * 2186 * (dyn_dir != MATCH_UNKNOWN && 2187 * dyn_name != 0 && dyn_name != cmd->arg1) 2188 * means previous lookup didn't find dynamic 2189 * rule for specific state name and current 2190 * lookup will search rule with another state 2191 * name. Redo lookup. 2192 * 2193 * (dyn_dir != MATCH_UNKNOWN && dyn_name == 0) 2194 * means previous lookup was for `any' name 2195 * and it didn't find rule. No need to do 2196 * lookup again. 2197 */ 2198 if ((dyn_dir == MATCH_UNKNOWN || 2199 (dyn_name != 0 && 2200 dyn_name != cmd->arg1)) && 2201 (q = ipfw_lookup_dyn_rule(&args->f_id, 2202 &dyn_dir, proto == IPPROTO_TCP ? 2203 TCP(ulp): NULL, 2204 (dyn_name = cmd->arg1))) != NULL) { 2205 /* 2206 * Found dynamic entry, update stats 2207 * and jump to the 'action' part of 2208 * the parent rule by setting 2209 * f, cmd, l and clearing cmdlen. 2210 */ 2211 IPFW_INC_DYN_COUNTER(q, pktlen); 2212 /* XXX we would like to have f_pos 2213 * readily accessible in the dynamic 2214 * rule, instead of having to 2215 * lookup q->rule. 2216 */ 2217 f = q->rule; 2218 f_pos = ipfw_find_rule(chain, 2219 f->rulenum, f->id); 2220 cmd = ACTION_PTR(f); 2221 l = f->cmd_len - f->act_ofs; 2222 ipfw_dyn_unlock(q); 2223 cmdlen = 0; 2224 match = 1; 2225 break; 2226 } 2227 /* 2228 * Dynamic entry not found. If CHECK_STATE, 2229 * skip to next rule, if PROBE_STATE just 2230 * ignore and continue with next opcode. 2231 */ 2232 if (cmd->opcode == O_CHECK_STATE) 2233 l = 0; /* exit inner loop */ 2234 match = 1; 2235 break; 2236 2237 case O_ACCEPT: 2238 retval = 0; /* accept */ 2239 l = 0; /* exit inner loop */ 2240 done = 1; /* exit outer loop */ 2241 break; 2242 2243 case O_PIPE: 2244 case O_QUEUE: 2245 set_match(args, f_pos, chain); 2246 args->rule.info = TARG(cmd->arg1, pipe); 2247 if (cmd->opcode == O_PIPE) 2248 args->rule.info |= IPFW_IS_PIPE; 2249 if (V_fw_one_pass) 2250 args->rule.info |= IPFW_ONEPASS; 2251 retval = IP_FW_DUMMYNET; 2252 l = 0; /* exit inner loop */ 2253 done = 1; /* exit outer loop */ 2254 break; 2255 2256 case O_DIVERT: 2257 case O_TEE: 2258 if (args->eh) /* not on layer 2 */ 2259 break; 2260 /* otherwise this is terminal */ 2261 l = 0; /* exit inner loop */ 2262 done = 1; /* exit outer loop */ 2263 retval = (cmd->opcode == O_DIVERT) ? 2264 IP_FW_DIVERT : IP_FW_TEE; 2265 set_match(args, f_pos, chain); 2266 args->rule.info = TARG(cmd->arg1, divert); 2267 break; 2268 2269 case O_COUNT: 2270 IPFW_INC_RULE_COUNTER(f, pktlen); 2271 l = 0; /* exit inner loop */ 2272 break; 2273 2274 case O_SKIPTO: 2275 IPFW_INC_RULE_COUNTER(f, pktlen); 2276 f_pos = JUMP(chain, f, cmd->arg1, tablearg, 0); 2277 /* 2278 * Skip disabled rules, and re-enter 2279 * the inner loop with the correct 2280 * f_pos, f, l and cmd. 2281 * Also clear cmdlen and skip_or 2282 */ 2283 for (; f_pos < chain->n_rules - 1 && 2284 (V_set_disable & 2285 (1 << chain->map[f_pos]->set)); 2286 f_pos++) 2287 ; 2288 /* Re-enter the inner loop at the skipto rule. */ 2289 f = chain->map[f_pos]; 2290 l = f->cmd_len; 2291 cmd = f->cmd; 2292 match = 1; 2293 cmdlen = 0; 2294 skip_or = 0; 2295 continue; 2296 break; /* not reached */ 2297 2298 case O_CALLRETURN: { 2299 /* 2300 * Implementation of `subroutine' call/return, 2301 * in the stack carried in an mbuf tag. This 2302 * is different from `skipto' in that any call 2303 * address is possible (`skipto' must prevent 2304 * backward jumps to avoid endless loops). 2305 * We have `return' action when F_NOT flag is 2306 * present. The `m_tag_id' field is used as 2307 * stack pointer. 2308 */ 2309 struct m_tag *mtag; 2310 uint16_t jmpto, *stack; 2311 2312 #define IS_CALL ((cmd->len & F_NOT) == 0) 2313 #define IS_RETURN ((cmd->len & F_NOT) != 0) 2314 /* 2315 * Hand-rolled version of m_tag_locate() with 2316 * wildcard `type'. 2317 * If not already tagged, allocate new tag. 2318 */ 2319 mtag = m_tag_first(m); 2320 while (mtag != NULL) { 2321 if (mtag->m_tag_cookie == 2322 MTAG_IPFW_CALL) 2323 break; 2324 mtag = m_tag_next(m, mtag); 2325 } 2326 if (mtag == NULL && IS_CALL) { 2327 mtag = m_tag_alloc(MTAG_IPFW_CALL, 0, 2328 IPFW_CALLSTACK_SIZE * 2329 sizeof(uint16_t), M_NOWAIT); 2330 if (mtag != NULL) 2331 m_tag_prepend(m, mtag); 2332 } 2333 2334 /* 2335 * On error both `call' and `return' just 2336 * continue with next rule. 2337 */ 2338 if (IS_RETURN && (mtag == NULL || 2339 mtag->m_tag_id == 0)) { 2340 l = 0; /* exit inner loop */ 2341 break; 2342 } 2343 if (IS_CALL && (mtag == NULL || 2344 mtag->m_tag_id >= IPFW_CALLSTACK_SIZE)) { 2345 printf("ipfw: call stack error, " 2346 "go to next rule\n"); 2347 l = 0; /* exit inner loop */ 2348 break; 2349 } 2350 2351 IPFW_INC_RULE_COUNTER(f, pktlen); 2352 stack = (uint16_t *)(mtag + 1); 2353 2354 /* 2355 * The `call' action may use cached f_pos 2356 * (in f->next_rule), whose version is written 2357 * in f->next_rule. 2358 * The `return' action, however, doesn't have 2359 * fixed jump address in cmd->arg1 and can't use 2360 * cache. 2361 */ 2362 if (IS_CALL) { 2363 stack[mtag->m_tag_id] = f->rulenum; 2364 mtag->m_tag_id++; 2365 f_pos = JUMP(chain, f, cmd->arg1, 2366 tablearg, 1); 2367 } else { /* `return' action */ 2368 mtag->m_tag_id--; 2369 jmpto = stack[mtag->m_tag_id] + 1; 2370 f_pos = ipfw_find_rule(chain, jmpto, 0); 2371 } 2372 2373 /* 2374 * Skip disabled rules, and re-enter 2375 * the inner loop with the correct 2376 * f_pos, f, l and cmd. 2377 * Also clear cmdlen and skip_or 2378 */ 2379 for (; f_pos < chain->n_rules - 1 && 2380 (V_set_disable & 2381 (1 << chain->map[f_pos]->set)); f_pos++) 2382 ; 2383 /* Re-enter the inner loop at the dest rule. */ 2384 f = chain->map[f_pos]; 2385 l = f->cmd_len; 2386 cmd = f->cmd; 2387 cmdlen = 0; 2388 skip_or = 0; 2389 continue; 2390 break; /* NOTREACHED */ 2391 } 2392 #undef IS_CALL 2393 #undef IS_RETURN 2394 2395 case O_REJECT: 2396 /* 2397 * Drop the packet and send a reject notice 2398 * if the packet is not ICMP (or is an ICMP 2399 * query), and it is not multicast/broadcast. 2400 */ 2401 if (hlen > 0 && is_ipv4 && offset == 0 && 2402 (proto != IPPROTO_ICMP || 2403 is_icmp_query(ICMP(ulp))) && 2404 !(m->m_flags & (M_BCAST|M_MCAST)) && 2405 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2406 send_reject(args, cmd->arg1, iplen, ip); 2407 m = args->m; 2408 } 2409 /* FALLTHROUGH */ 2410 #ifdef INET6 2411 case O_UNREACH6: 2412 if (hlen > 0 && is_ipv6 && 2413 ((offset & IP6F_OFF_MASK) == 0) && 2414 (proto != IPPROTO_ICMPV6 || 2415 (is_icmp6_query(icmp6_type) == 1)) && 2416 !(m->m_flags & (M_BCAST|M_MCAST)) && 2417 !IN6_IS_ADDR_MULTICAST(&args->f_id.dst_ip6)) { 2418 send_reject6( 2419 args, cmd->arg1, hlen, 2420 (struct ip6_hdr *)ip); 2421 m = args->m; 2422 } 2423 /* FALLTHROUGH */ 2424 #endif 2425 case O_DENY: 2426 retval = IP_FW_DENY; 2427 l = 0; /* exit inner loop */ 2428 done = 1; /* exit outer loop */ 2429 break; 2430 2431 case O_FORWARD_IP: 2432 if (args->eh) /* not valid on layer2 pkts */ 2433 break; 2434 if (q == NULL || q->rule != f || 2435 dyn_dir == MATCH_FORWARD) { 2436 struct sockaddr_in *sa; 2437 2438 sa = &(((ipfw_insn_sa *)cmd)->sa); 2439 if (sa->sin_addr.s_addr == INADDR_ANY) { 2440 #ifdef INET6 2441 /* 2442 * We use O_FORWARD_IP opcode for 2443 * fwd rule with tablearg, but tables 2444 * now support IPv6 addresses. And 2445 * when we are inspecting IPv6 packet, 2446 * we can use nh6 field from 2447 * table_value as next_hop6 address. 2448 */ 2449 if (is_ipv6) { 2450 struct sockaddr_in6 *sa6; 2451 2452 sa6 = args->next_hop6 = 2453 &args->hopstore6; 2454 sa6->sin6_family = AF_INET6; 2455 sa6->sin6_len = sizeof(*sa6); 2456 sa6->sin6_addr = TARG_VAL( 2457 chain, tablearg, nh6); 2458 sa6->sin6_port = sa->sin_port; 2459 /* 2460 * Set sin6_scope_id only for 2461 * link-local unicast addresses. 2462 */ 2463 if (IN6_IS_ADDR_LINKLOCAL( 2464 &sa6->sin6_addr)) 2465 sa6->sin6_scope_id = 2466 TARG_VAL(chain, 2467 tablearg, 2468 zoneid); 2469 } else 2470 #endif 2471 { 2472 args->hopstore.sin_port = 2473 sa->sin_port; 2474 sa = args->next_hop = 2475 &args->hopstore; 2476 sa->sin_family = AF_INET; 2477 sa->sin_len = sizeof(*sa); 2478 sa->sin_addr.s_addr = htonl( 2479 TARG_VAL(chain, tablearg, 2480 nh4)); 2481 } 2482 } else { 2483 args->next_hop = sa; 2484 } 2485 } 2486 retval = IP_FW_PASS; 2487 l = 0; /* exit inner loop */ 2488 done = 1; /* exit outer loop */ 2489 break; 2490 2491 #ifdef INET6 2492 case O_FORWARD_IP6: 2493 if (args->eh) /* not valid on layer2 pkts */ 2494 break; 2495 if (q == NULL || q->rule != f || 2496 dyn_dir == MATCH_FORWARD) { 2497 struct sockaddr_in6 *sin6; 2498 2499 sin6 = &(((ipfw_insn_sa6 *)cmd)->sa); 2500 args->next_hop6 = sin6; 2501 } 2502 retval = IP_FW_PASS; 2503 l = 0; /* exit inner loop */ 2504 done = 1; /* exit outer loop */ 2505 break; 2506 #endif 2507 2508 case O_NETGRAPH: 2509 case O_NGTEE: 2510 set_match(args, f_pos, chain); 2511 args->rule.info = TARG(cmd->arg1, netgraph); 2512 if (V_fw_one_pass) 2513 args->rule.info |= IPFW_ONEPASS; 2514 retval = (cmd->opcode == O_NETGRAPH) ? 2515 IP_FW_NETGRAPH : IP_FW_NGTEE; 2516 l = 0; /* exit inner loop */ 2517 done = 1; /* exit outer loop */ 2518 break; 2519 2520 case O_SETFIB: { 2521 uint32_t fib; 2522 2523 IPFW_INC_RULE_COUNTER(f, pktlen); 2524 fib = TARG(cmd->arg1, fib) & 0x7FFF; 2525 if (fib >= rt_numfibs) 2526 fib = 0; 2527 M_SETFIB(m, fib); 2528 args->f_id.fib = fib; 2529 l = 0; /* exit inner loop */ 2530 break; 2531 } 2532 2533 case O_SETDSCP: { 2534 uint16_t code; 2535 2536 code = TARG(cmd->arg1, dscp) & 0x3F; 2537 l = 0; /* exit inner loop */ 2538 if (is_ipv4) { 2539 uint16_t old; 2540 2541 old = *(uint16_t *)ip; 2542 ip->ip_tos = (code << 2) | 2543 (ip->ip_tos & 0x03); 2544 ip->ip_sum = cksum_adjust(ip->ip_sum, 2545 old, *(uint16_t *)ip); 2546 } else if (is_ipv6) { 2547 uint8_t *v; 2548 2549 v = &((struct ip6_hdr *)ip)->ip6_vfc; 2550 *v = (*v & 0xF0) | (code >> 2); 2551 v++; 2552 *v = (*v & 0x3F) | ((code & 0x03) << 6); 2553 } else 2554 break; 2555 2556 IPFW_INC_RULE_COUNTER(f, pktlen); 2557 break; 2558 } 2559 2560 case O_NAT: 2561 l = 0; /* exit inner loop */ 2562 done = 1; /* exit outer loop */ 2563 /* 2564 * Ensure that we do not invoke NAT handler for 2565 * non IPv4 packets. Libalias expects only IPv4. 2566 */ 2567 if (!is_ipv4 || !IPFW_NAT_LOADED) { 2568 retval = IP_FW_DENY; 2569 break; 2570 } 2571 2572 struct cfg_nat *t; 2573 int nat_id; 2574 2575 set_match(args, f_pos, chain); 2576 /* Check if this is 'global' nat rule */ 2577 if (cmd->arg1 == IP_FW_NAT44_GLOBAL) { 2578 retval = ipfw_nat_ptr(args, NULL, m); 2579 break; 2580 } 2581 t = ((ipfw_insn_nat *)cmd)->nat; 2582 if (t == NULL) { 2583 nat_id = TARG(cmd->arg1, nat); 2584 t = (*lookup_nat_ptr)(&chain->nat, nat_id); 2585 2586 if (t == NULL) { 2587 retval = IP_FW_DENY; 2588 break; 2589 } 2590 if (cmd->arg1 != IP_FW_TARG) 2591 ((ipfw_insn_nat *)cmd)->nat = t; 2592 } 2593 retval = ipfw_nat_ptr(args, t, m); 2594 break; 2595 2596 case O_REASS: { 2597 int ip_off; 2598 2599 IPFW_INC_RULE_COUNTER(f, pktlen); 2600 l = 0; /* in any case exit inner loop */ 2601 ip_off = ntohs(ip->ip_off); 2602 2603 /* if not fragmented, go to next rule */ 2604 if ((ip_off & (IP_MF | IP_OFFMASK)) == 0) 2605 break; 2606 2607 args->m = m = ip_reass(m); 2608 2609 /* 2610 * do IP header checksum fixup. 2611 */ 2612 if (m == NULL) { /* fragment got swallowed */ 2613 retval = IP_FW_DENY; 2614 } else { /* good, packet complete */ 2615 int hlen; 2616 2617 ip = mtod(m, struct ip *); 2618 hlen = ip->ip_hl << 2; 2619 ip->ip_sum = 0; 2620 if (hlen == sizeof(struct ip)) 2621 ip->ip_sum = in_cksum_hdr(ip); 2622 else 2623 ip->ip_sum = in_cksum(m, hlen); 2624 retval = IP_FW_REASS; 2625 set_match(args, f_pos, chain); 2626 } 2627 done = 1; /* exit outer loop */ 2628 break; 2629 } 2630 case O_EXTERNAL_ACTION: 2631 l = 0; /* in any case exit inner loop */ 2632 retval = ipfw_run_eaction(chain, args, 2633 cmd, &done); 2634 /* 2635 * If both @retval and @done are zero, 2636 * consider this as rule matching and 2637 * update counters. 2638 */ 2639 if (retval == 0 && done == 0) { 2640 IPFW_INC_RULE_COUNTER(f, pktlen); 2641 /* 2642 * Reset the result of the last 2643 * dynamic state lookup. 2644 * External action can change 2645 * @args content, and it may be 2646 * used for new state lookup later. 2647 */ 2648 dyn_dir = MATCH_UNKNOWN; 2649 } 2650 break; 2651 2652 default: 2653 panic("-- unknown opcode %d\n", cmd->opcode); 2654 } /* end of switch() on opcodes */ 2655 /* 2656 * if we get here with l=0, then match is irrelevant. 2657 */ 2658 2659 if (cmd->len & F_NOT) 2660 match = !match; 2661 2662 if (match) { 2663 if (cmd->len & F_OR) 2664 skip_or = 1; 2665 } else { 2666 if (!(cmd->len & F_OR)) /* not an OR block, */ 2667 break; /* try next rule */ 2668 } 2669 2670 } /* end of inner loop, scan opcodes */ 2671 #undef PULLUP_LEN 2672 2673 if (done) 2674 break; 2675 2676 /* next_rule:; */ /* try next rule */ 2677 2678 } /* end of outer for, scan rules */ 2679 2680 if (done) { 2681 struct ip_fw *rule = chain->map[f_pos]; 2682 /* Update statistics */ 2683 IPFW_INC_RULE_COUNTER(rule, pktlen); 2684 } else { 2685 retval = IP_FW_DENY; 2686 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 2687 } 2688 IPFW_PF_RUNLOCK(chain); 2689 #ifdef __FreeBSD__ 2690 if (ucred_cache != NULL) 2691 crfree(ucred_cache); 2692 #endif 2693 return (retval); 2694 2695 pullup_failed: 2696 if (V_fw_verbose) 2697 printf("ipfw: pullup failed\n"); 2698 return (IP_FW_DENY); 2699 } 2700 2701 /* 2702 * Set maximum number of tables that can be used in given VNET ipfw instance. 2703 */ 2704 #ifdef SYSCTL_NODE 2705 static int 2706 sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS) 2707 { 2708 int error; 2709 unsigned int ntables; 2710 2711 ntables = V_fw_tables_max; 2712 2713 error = sysctl_handle_int(oidp, &ntables, 0, req); 2714 /* Read operation or some error */ 2715 if ((error != 0) || (req->newptr == NULL)) 2716 return (error); 2717 2718 return (ipfw_resize_tables(&V_layer3_chain, ntables)); 2719 } 2720 2721 /* 2722 * Switches table namespace between global and per-set. 2723 */ 2724 static int 2725 sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS) 2726 { 2727 int error; 2728 unsigned int sets; 2729 2730 sets = V_fw_tables_sets; 2731 2732 error = sysctl_handle_int(oidp, &sets, 0, req); 2733 /* Read operation or some error */ 2734 if ((error != 0) || (req->newptr == NULL)) 2735 return (error); 2736 2737 return (ipfw_switch_tables_namespace(&V_layer3_chain, sets)); 2738 } 2739 #endif 2740 2741 /* 2742 * Module and VNET glue 2743 */ 2744 2745 /* 2746 * Stuff that must be initialised only on boot or module load 2747 */ 2748 static int 2749 ipfw_init(void) 2750 { 2751 int error = 0; 2752 2753 /* 2754 * Only print out this stuff the first time around, 2755 * when called from the sysinit code. 2756 */ 2757 printf("ipfw2 " 2758 #ifdef INET6 2759 "(+ipv6) " 2760 #endif 2761 "initialized, divert %s, nat %s, " 2762 "default to %s, logging ", 2763 #ifdef IPDIVERT 2764 "enabled", 2765 #else 2766 "loadable", 2767 #endif 2768 #ifdef IPFIREWALL_NAT 2769 "enabled", 2770 #else 2771 "loadable", 2772 #endif 2773 default_to_accept ? "accept" : "deny"); 2774 2775 /* 2776 * Note: V_xxx variables can be accessed here but the vnet specific 2777 * initializer may not have been called yet for the VIMAGE case. 2778 * Tuneables will have been processed. We will print out values for 2779 * the default vnet. 2780 * XXX This should all be rationalized AFTER 8.0 2781 */ 2782 if (V_fw_verbose == 0) 2783 printf("disabled\n"); 2784 else if (V_verbose_limit == 0) 2785 printf("unlimited\n"); 2786 else 2787 printf("limited to %d packets/entry by default\n", 2788 V_verbose_limit); 2789 2790 /* Check user-supplied table count for validness */ 2791 if (default_fw_tables > IPFW_TABLES_MAX) 2792 default_fw_tables = IPFW_TABLES_MAX; 2793 2794 ipfw_init_sopt_handler(); 2795 ipfw_init_obj_rewriter(); 2796 ipfw_iface_init(); 2797 return (error); 2798 } 2799 2800 /* 2801 * Called for the removal of the last instance only on module unload. 2802 */ 2803 static void 2804 ipfw_destroy(void) 2805 { 2806 2807 ipfw_iface_destroy(); 2808 ipfw_destroy_sopt_handler(); 2809 ipfw_destroy_obj_rewriter(); 2810 printf("IP firewall unloaded\n"); 2811 } 2812 2813 /* 2814 * Stuff that must be initialized for every instance 2815 * (including the first of course). 2816 */ 2817 static int 2818 vnet_ipfw_init(const void *unused) 2819 { 2820 int error, first; 2821 struct ip_fw *rule = NULL; 2822 struct ip_fw_chain *chain; 2823 2824 chain = &V_layer3_chain; 2825 2826 first = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 2827 2828 /* First set up some values that are compile time options */ 2829 V_autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 2830 V_fw_deny_unknown_exthdrs = 1; 2831 #ifdef IPFIREWALL_VERBOSE 2832 V_fw_verbose = 1; 2833 #endif 2834 #ifdef IPFIREWALL_VERBOSE_LIMIT 2835 V_verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 2836 #endif 2837 #ifdef IPFIREWALL_NAT 2838 LIST_INIT(&chain->nat); 2839 #endif 2840 2841 /* Init shared services hash table */ 2842 ipfw_init_srv(chain); 2843 2844 ipfw_init_counters(); 2845 /* insert the default rule and create the initial map */ 2846 chain->n_rules = 1; 2847 chain->map = malloc(sizeof(struct ip_fw *), M_IPFW, M_WAITOK | M_ZERO); 2848 rule = ipfw_alloc_rule(chain, sizeof(struct ip_fw)); 2849 2850 /* Set initial number of tables */ 2851 V_fw_tables_max = default_fw_tables; 2852 error = ipfw_init_tables(chain, first); 2853 if (error) { 2854 printf("ipfw2: setting up tables failed\n"); 2855 free(chain->map, M_IPFW); 2856 free(rule, M_IPFW); 2857 return (ENOSPC); 2858 } 2859 2860 /* fill and insert the default rule */ 2861 rule->act_ofs = 0; 2862 rule->rulenum = IPFW_DEFAULT_RULE; 2863 rule->cmd_len = 1; 2864 rule->set = RESVD_SET; 2865 rule->cmd[0].len = 1; 2866 rule->cmd[0].opcode = default_to_accept ? O_ACCEPT : O_DENY; 2867 chain->default_rule = chain->map[0] = rule; 2868 chain->id = rule->id = 1; 2869 /* Pre-calculate rules length for legacy dump format */ 2870 chain->static_len = sizeof(struct ip_fw_rule0); 2871 2872 IPFW_LOCK_INIT(chain); 2873 ipfw_dyn_init(chain); 2874 ipfw_eaction_init(chain, first); 2875 #ifdef LINEAR_SKIPTO 2876 ipfw_init_skipto_cache(chain); 2877 #endif 2878 ipfw_bpf_init(first); 2879 2880 /* First set up some values that are compile time options */ 2881 V_ipfw_vnet_ready = 1; /* Open for business */ 2882 2883 /* 2884 * Hook the sockopt handler and pfil hooks for ipv4 and ipv6. 2885 * Even if the latter two fail we still keep the module alive 2886 * because the sockopt and layer2 paths are still useful. 2887 * ipfw[6]_hook return 0 on success, ENOENT on failure, 2888 * so we can ignore the exact return value and just set a flag. 2889 * 2890 * Note that V_fw[6]_enable are manipulated by a SYSCTL_PROC so 2891 * changes in the underlying (per-vnet) variables trigger 2892 * immediate hook()/unhook() calls. 2893 * In layer2 we have the same behaviour, except that V_ether_ipfw 2894 * is checked on each packet because there are no pfil hooks. 2895 */ 2896 V_ip_fw_ctl_ptr = ipfw_ctl3; 2897 error = ipfw_attach_hooks(1); 2898 return (error); 2899 } 2900 2901 /* 2902 * Called for the removal of each instance. 2903 */ 2904 static int 2905 vnet_ipfw_uninit(const void *unused) 2906 { 2907 struct ip_fw *reap; 2908 struct ip_fw_chain *chain = &V_layer3_chain; 2909 int i, last; 2910 2911 V_ipfw_vnet_ready = 0; /* tell new callers to go away */ 2912 /* 2913 * disconnect from ipv4, ipv6, layer2 and sockopt. 2914 * Then grab, release and grab again the WLOCK so we make 2915 * sure the update is propagated and nobody will be in. 2916 */ 2917 (void)ipfw_attach_hooks(0 /* detach */); 2918 V_ip_fw_ctl_ptr = NULL; 2919 2920 last = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 2921 2922 IPFW_UH_WLOCK(chain); 2923 IPFW_UH_WUNLOCK(chain); 2924 2925 ipfw_dyn_uninit(0); /* run the callout_drain */ 2926 2927 IPFW_UH_WLOCK(chain); 2928 2929 reap = NULL; 2930 IPFW_WLOCK(chain); 2931 for (i = 0; i < chain->n_rules; i++) 2932 ipfw_reap_add(chain, &reap, chain->map[i]); 2933 free(chain->map, M_IPFW); 2934 #ifdef LINEAR_SKIPTO 2935 ipfw_destroy_skipto_cache(chain); 2936 #endif 2937 IPFW_WUNLOCK(chain); 2938 IPFW_UH_WUNLOCK(chain); 2939 ipfw_destroy_tables(chain, last); 2940 ipfw_eaction_uninit(chain, last); 2941 if (reap != NULL) 2942 ipfw_reap_rules(reap); 2943 vnet_ipfw_iface_destroy(chain); 2944 ipfw_destroy_srv(chain); 2945 IPFW_LOCK_DESTROY(chain); 2946 ipfw_dyn_uninit(1); /* free the remaining parts */ 2947 ipfw_destroy_counters(); 2948 ipfw_bpf_uninit(last); 2949 return (0); 2950 } 2951 2952 /* 2953 * Module event handler. 2954 * In general we have the choice of handling most of these events by the 2955 * event handler or by the (VNET_)SYS(UN)INIT handlers. I have chosen to 2956 * use the SYSINIT handlers as they are more capable of expressing the 2957 * flow of control during module and vnet operations, so this is just 2958 * a skeleton. Note there is no SYSINIT equivalent of the module 2959 * SHUTDOWN handler, but we don't have anything to do in that case anyhow. 2960 */ 2961 static int 2962 ipfw_modevent(module_t mod, int type, void *unused) 2963 { 2964 int err = 0; 2965 2966 switch (type) { 2967 case MOD_LOAD: 2968 /* Called once at module load or 2969 * system boot if compiled in. */ 2970 break; 2971 case MOD_QUIESCE: 2972 /* Called before unload. May veto unloading. */ 2973 break; 2974 case MOD_UNLOAD: 2975 /* Called during unload. */ 2976 break; 2977 case MOD_SHUTDOWN: 2978 /* Called during system shutdown. */ 2979 break; 2980 default: 2981 err = EOPNOTSUPP; 2982 break; 2983 } 2984 return err; 2985 } 2986 2987 static moduledata_t ipfwmod = { 2988 "ipfw", 2989 ipfw_modevent, 2990 0 2991 }; 2992 2993 /* Define startup order. */ 2994 #define IPFW_SI_SUB_FIREWALL SI_SUB_PROTO_FIREWALL 2995 #define IPFW_MODEVENT_ORDER (SI_ORDER_ANY - 255) /* On boot slot in here. */ 2996 #define IPFW_MODULE_ORDER (IPFW_MODEVENT_ORDER + 1) /* A little later. */ 2997 #define IPFW_VNET_ORDER (IPFW_MODEVENT_ORDER + 2) /* Later still. */ 2998 2999 DECLARE_MODULE(ipfw, ipfwmod, IPFW_SI_SUB_FIREWALL, IPFW_MODEVENT_ORDER); 3000 FEATURE(ipfw_ctl3, "ipfw new sockopt calls"); 3001 MODULE_VERSION(ipfw, 3); 3002 /* should declare some dependencies here */ 3003 3004 /* 3005 * Starting up. Done in order after ipfwmod() has been called. 3006 * VNET_SYSINIT is also called for each existing vnet and each new vnet. 3007 */ 3008 SYSINIT(ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 3009 ipfw_init, NULL); 3010 VNET_SYSINIT(vnet_ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 3011 vnet_ipfw_init, NULL); 3012 3013 /* 3014 * Closing up shop. These are done in REVERSE ORDER, but still 3015 * after ipfwmod() has been called. Not called on reboot. 3016 * VNET_SYSUNINIT is also called for each exiting vnet as it exits. 3017 * or when the module is unloaded. 3018 */ 3019 SYSUNINIT(ipfw_destroy, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 3020 ipfw_destroy, NULL); 3021 VNET_SYSUNINIT(vnet_ipfw_uninit, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 3022 vnet_ipfw_uninit, NULL); 3023 /* end of file */ 3024