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 #include "opt_ipsec.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/condvar.h> 45 #include <sys/counter.h> 46 #include <sys/eventhandler.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/jail.h> 52 #include <sys/module.h> 53 #include <sys/priv.h> 54 #include <sys/proc.h> 55 #include <sys/rwlock.h> 56 #include <sys/rmlock.h> 57 #include <sys/socket.h> 58 #include <sys/socketvar.h> 59 #include <sys/sysctl.h> 60 #include <sys/syslog.h> 61 #include <sys/ucred.h> 62 #include <net/ethernet.h> /* for ETHERTYPE_IP */ 63 #include <net/if.h> 64 #include <net/if_var.h> 65 #include <net/route.h> 66 #include <net/pfil.h> 67 #include <net/vnet.h> 68 69 #include <netpfil/pf/pf_mtag.h> 70 71 #include <netinet/in.h> 72 #include <netinet/in_var.h> 73 #include <netinet/in_pcb.h> 74 #include <netinet/ip.h> 75 #include <netinet/ip_var.h> 76 #include <netinet/ip_icmp.h> 77 #include <netinet/ip_fw.h> 78 #include <netinet/ip_carp.h> 79 #include <netinet/pim.h> 80 #include <netinet/tcp_var.h> 81 #include <netinet/udp.h> 82 #include <netinet/udp_var.h> 83 #include <netinet/sctp.h> 84 85 #include <netinet/ip6.h> 86 #include <netinet/icmp6.h> 87 #include <netinet/in_fib.h> 88 #ifdef INET6 89 #include <netinet6/in6_fib.h> 90 #include <netinet6/in6_pcb.h> 91 #include <netinet6/scope6_var.h> 92 #include <netinet6/ip6_var.h> 93 #endif 94 95 #include <net/if_gre.h> /* for struct grehdr */ 96 97 #include <netpfil/ipfw/ip_fw_private.h> 98 99 #include <machine/in_cksum.h> /* XXX for in_cksum */ 100 101 #ifdef MAC 102 #include <security/mac/mac_framework.h> 103 #endif 104 105 /* 106 * static variables followed by global ones. 107 * All ipfw global variables are here. 108 */ 109 110 static VNET_DEFINE(int, fw_deny_unknown_exthdrs); 111 #define V_fw_deny_unknown_exthdrs VNET(fw_deny_unknown_exthdrs) 112 113 static VNET_DEFINE(int, fw_permit_single_frag6) = 1; 114 #define V_fw_permit_single_frag6 VNET(fw_permit_single_frag6) 115 116 #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 117 static int default_to_accept = 1; 118 #else 119 static int default_to_accept; 120 #endif 121 122 VNET_DEFINE(int, autoinc_step); 123 VNET_DEFINE(int, fw_one_pass) = 1; 124 125 VNET_DEFINE(unsigned int, fw_tables_max); 126 VNET_DEFINE(unsigned int, fw_tables_sets) = 0; /* Don't use set-aware tables */ 127 /* Use 128 tables by default */ 128 static unsigned int default_fw_tables = IPFW_TABLES_DEFAULT; 129 130 #ifndef LINEAR_SKIPTO 131 static int jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 132 int tablearg, int jump_backwards); 133 #define JUMP(ch, f, num, targ, back) jump_fast(ch, f, num, targ, back) 134 #else 135 static int jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num, 136 int tablearg, int jump_backwards); 137 #define JUMP(ch, f, num, targ, back) jump_linear(ch, f, num, targ, back) 138 #endif 139 140 /* 141 * Each rule belongs to one of 32 different sets (0..31). 142 * The variable set_disable contains one bit per set. 143 * If the bit is set, all rules in the corresponding set 144 * are disabled. Set RESVD_SET(31) is reserved for the default rule 145 * and rules that are not deleted by the flush command, 146 * and CANNOT be disabled. 147 * Rules in set RESVD_SET can only be deleted individually. 148 */ 149 VNET_DEFINE(u_int32_t, set_disable); 150 #define V_set_disable VNET(set_disable) 151 152 VNET_DEFINE(int, fw_verbose); 153 /* counter for ipfw_log(NULL...) */ 154 VNET_DEFINE(u_int64_t, norule_counter); 155 VNET_DEFINE(int, verbose_limit); 156 157 /* layer3_chain contains the list of rules for layer 3 */ 158 VNET_DEFINE(struct ip_fw_chain, layer3_chain); 159 160 /* ipfw_vnet_ready controls when we are open for business */ 161 VNET_DEFINE(int, ipfw_vnet_ready) = 0; 162 163 VNET_DEFINE(int, ipfw_nat_ready) = 0; 164 165 ipfw_nat_t *ipfw_nat_ptr = NULL; 166 struct cfg_nat *(*lookup_nat_ptr)(struct nat_list *, int); 167 ipfw_nat_cfg_t *ipfw_nat_cfg_ptr; 168 ipfw_nat_cfg_t *ipfw_nat_del_ptr; 169 ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr; 170 ipfw_nat_cfg_t *ipfw_nat_get_log_ptr; 171 172 #ifdef SYSCTL_NODE 173 uint32_t dummy_def = IPFW_DEFAULT_RULE; 174 static int sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS); 175 static int sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS); 176 177 SYSBEGIN(f3) 178 179 SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 180 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 181 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_one_pass), 0, 182 "Only do a single pass through ipfw when using dummynet(4)"); 183 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, 184 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(autoinc_step), 0, 185 "Rule number auto-increment step"); 186 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, 187 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_verbose), 0, 188 "Log matches to ipfw rules"); 189 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, 190 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(verbose_limit), 0, 191 "Set upper limit of matches of ipfw rules logged"); 192 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, default_rule, CTLFLAG_RD, 193 &dummy_def, 0, 194 "The default/max possible rule number."); 195 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_max, 196 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_table_num, "IU", 197 "Maximum number of concurrently used tables"); 198 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, tables_sets, 199 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 200 0, 0, sysctl_ipfw_tables_sets, "IU", 201 "Use per-set namespace for tables"); 202 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, default_to_accept, CTLFLAG_RDTUN, 203 &default_to_accept, 0, 204 "Make the default rule accept all packets."); 205 TUNABLE_INT("net.inet.ip.fw.tables_max", (int *)&default_fw_tables); 206 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, 207 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(layer3_chain.n_rules), 0, 208 "Number of static rules"); 209 210 #ifdef INET6 211 SYSCTL_DECL(_net_inet6_ip6); 212 SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 213 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, deny_unknown_exthdrs, 214 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 215 &VNET_NAME(fw_deny_unknown_exthdrs), 0, 216 "Deny packets with unknown IPv6 Extension Headers"); 217 SYSCTL_INT(_net_inet6_ip6_fw, OID_AUTO, permit_single_frag6, 218 CTLFLAG_VNET | CTLFLAG_RW | CTLFLAG_SECURE, 219 &VNET_NAME(fw_permit_single_frag6), 0, 220 "Permit single packet IPv6 fragments"); 221 #endif /* INET6 */ 222 223 SYSEND 224 225 #endif /* SYSCTL_NODE */ 226 227 228 /* 229 * Some macros used in the various matching options. 230 * L3HDR maps an ipv4 pointer into a layer3 header pointer of type T 231 * Other macros just cast void * into the appropriate type 232 */ 233 #define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 234 #define TCP(p) ((struct tcphdr *)(p)) 235 #define SCTP(p) ((struct sctphdr *)(p)) 236 #define UDP(p) ((struct udphdr *)(p)) 237 #define ICMP(p) ((struct icmphdr *)(p)) 238 #define ICMP6(p) ((struct icmp6_hdr *)(p)) 239 240 static __inline int 241 icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd) 242 { 243 int type = icmp->icmp_type; 244 245 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 246 } 247 248 #define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 249 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 250 251 static int 252 is_icmp_query(struct icmphdr *icmp) 253 { 254 int type = icmp->icmp_type; 255 256 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 257 } 258 #undef TT 259 260 /* 261 * The following checks use two arrays of 8 or 16 bits to store the 262 * bits that we want set or clear, respectively. They are in the 263 * low and high half of cmd->arg1 or cmd->d[0]. 264 * 265 * We scan options and store the bits we find set. We succeed if 266 * 267 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 268 * 269 * The code is sometimes optimized not to store additional variables. 270 */ 271 272 static int 273 flags_match(ipfw_insn *cmd, u_int8_t bits) 274 { 275 u_char want_clear; 276 bits = ~bits; 277 278 if ( ((cmd->arg1 & 0xff) & bits) != 0) 279 return 0; /* some bits we want set were clear */ 280 want_clear = (cmd->arg1 >> 8) & 0xff; 281 if ( (want_clear & bits) != want_clear) 282 return 0; /* some bits we want clear were set */ 283 return 1; 284 } 285 286 static int 287 ipopts_match(struct ip *ip, ipfw_insn *cmd) 288 { 289 int optlen, bits = 0; 290 u_char *cp = (u_char *)(ip + 1); 291 int x = (ip->ip_hl << 2) - sizeof (struct ip); 292 293 for (; x > 0; x -= optlen, cp += optlen) { 294 int opt = cp[IPOPT_OPTVAL]; 295 296 if (opt == IPOPT_EOL) 297 break; 298 if (opt == IPOPT_NOP) 299 optlen = 1; 300 else { 301 optlen = cp[IPOPT_OLEN]; 302 if (optlen <= 0 || optlen > x) 303 return 0; /* invalid or truncated */ 304 } 305 switch (opt) { 306 307 default: 308 break; 309 310 case IPOPT_LSRR: 311 bits |= IP_FW_IPOPT_LSRR; 312 break; 313 314 case IPOPT_SSRR: 315 bits |= IP_FW_IPOPT_SSRR; 316 break; 317 318 case IPOPT_RR: 319 bits |= IP_FW_IPOPT_RR; 320 break; 321 322 case IPOPT_TS: 323 bits |= IP_FW_IPOPT_TS; 324 break; 325 } 326 } 327 return (flags_match(cmd, bits)); 328 } 329 330 static int 331 tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd) 332 { 333 int optlen, bits = 0; 334 u_char *cp = (u_char *)(tcp + 1); 335 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 336 337 for (; x > 0; x -= optlen, cp += optlen) { 338 int opt = cp[0]; 339 if (opt == TCPOPT_EOL) 340 break; 341 if (opt == TCPOPT_NOP) 342 optlen = 1; 343 else { 344 optlen = cp[1]; 345 if (optlen <= 0) 346 break; 347 } 348 349 switch (opt) { 350 351 default: 352 break; 353 354 case TCPOPT_MAXSEG: 355 bits |= IP_FW_TCPOPT_MSS; 356 break; 357 358 case TCPOPT_WINDOW: 359 bits |= IP_FW_TCPOPT_WINDOW; 360 break; 361 362 case TCPOPT_SACK_PERMITTED: 363 case TCPOPT_SACK: 364 bits |= IP_FW_TCPOPT_SACK; 365 break; 366 367 case TCPOPT_TIMESTAMP: 368 bits |= IP_FW_TCPOPT_TS; 369 break; 370 371 } 372 } 373 return (flags_match(cmd, bits)); 374 } 375 376 static int 377 iface_match(struct ifnet *ifp, ipfw_insn_if *cmd, struct ip_fw_chain *chain, 378 uint32_t *tablearg) 379 { 380 381 if (ifp == NULL) /* no iface with this packet, match fails */ 382 return (0); 383 384 /* Check by name or by IP address */ 385 if (cmd->name[0] != '\0') { /* match by name */ 386 if (cmd->name[0] == '\1') /* use tablearg to match */ 387 return ipfw_lookup_table(chain, cmd->p.kidx, 0, 388 &ifp->if_index, tablearg); 389 /* Check name */ 390 if (cmd->p.glob) { 391 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 392 return(1); 393 } else { 394 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 395 return(1); 396 } 397 } else { 398 #if !defined(USERSPACE) && defined(__FreeBSD__) /* and OSX too ? */ 399 struct ifaddr *ia; 400 401 if_addr_rlock(ifp); 402 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 403 if (ia->ifa_addr->sa_family != AF_INET) 404 continue; 405 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 406 (ia->ifa_addr))->sin_addr.s_addr) { 407 if_addr_runlock(ifp); 408 return(1); /* match */ 409 } 410 } 411 if_addr_runlock(ifp); 412 #endif /* __FreeBSD__ */ 413 } 414 return(0); /* no match, fail ... */ 415 } 416 417 /* 418 * The verify_path function checks if a route to the src exists and 419 * if it is reachable via ifp (when provided). 420 * 421 * The 'verrevpath' option checks that the interface that an IP packet 422 * arrives on is the same interface that traffic destined for the 423 * packet's source address would be routed out of. 424 * The 'versrcreach' option just checks that the source address is 425 * reachable via any route (except default) in the routing table. 426 * These two are a measure to block forged packets. This is also 427 * commonly known as "anti-spoofing" or Unicast Reverse Path 428 * Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 429 * is purposely reminiscent of the Cisco IOS command, 430 * 431 * ip verify unicast reverse-path 432 * ip verify unicast source reachable-via any 433 * 434 * which implements the same functionality. But note that the syntax 435 * is misleading, and the check may be performed on all IP packets 436 * whether unicast, multicast, or broadcast. 437 */ 438 static int 439 verify_path(struct in_addr src, struct ifnet *ifp, u_int fib) 440 { 441 #if defined(USERSPACE) || !defined(__FreeBSD__) 442 return 0; 443 #else 444 struct nhop4_basic nh4; 445 446 if (fib4_lookup_nh_basic(fib, src, NHR_IFAIF, 0, &nh4) != 0) 447 return (0); 448 449 /* 450 * If ifp is provided, check for equality with rtentry. 451 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 452 * in order to pass packets injected back by if_simloop(): 453 * routing entry (via lo0) for our own address 454 * may exist, so we need to handle routing assymetry. 455 */ 456 if (ifp != NULL && ifp != nh4.nh_ifp) 457 return (0); 458 459 /* if no ifp provided, check if rtentry is not default route */ 460 if (ifp == NULL && (nh4.nh_flags & NHF_DEFAULT) != 0) 461 return (0); 462 463 /* or if this is a blackhole/reject route */ 464 if (ifp == NULL && (nh4.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 465 return (0); 466 467 /* found valid route */ 468 return 1; 469 #endif /* __FreeBSD__ */ 470 } 471 472 #ifdef INET6 473 /* 474 * ipv6 specific rules here... 475 */ 476 static __inline int 477 icmp6type_match (int type, ipfw_insn_u32 *cmd) 478 { 479 return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) ); 480 } 481 482 static int 483 flow6id_match( int curr_flow, ipfw_insn_u32 *cmd ) 484 { 485 int i; 486 for (i=0; i <= cmd->o.arg1; ++i ) 487 if (curr_flow == cmd->d[i] ) 488 return 1; 489 return 0; 490 } 491 492 /* support for IP6_*_ME opcodes */ 493 static const struct in6_addr lla_mask = {{{ 494 0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 495 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff 496 }}}; 497 498 static int 499 ipfw_localip6(struct in6_addr *in6) 500 { 501 struct rm_priotracker in6_ifa_tracker; 502 struct in6_ifaddr *ia; 503 504 if (IN6_IS_ADDR_MULTICAST(in6)) 505 return (0); 506 507 if (!IN6_IS_ADDR_LINKLOCAL(in6)) 508 return (in6_localip(in6)); 509 510 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 511 TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 512 if (!IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) 513 continue; 514 if (IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr, 515 in6, &lla_mask)) { 516 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 517 return (1); 518 } 519 } 520 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 521 return (0); 522 } 523 524 static int 525 verify_path6(struct in6_addr *src, struct ifnet *ifp, u_int fib) 526 { 527 struct nhop6_basic nh6; 528 529 if (IN6_IS_SCOPE_LINKLOCAL(src)) 530 return (1); 531 532 if (fib6_lookup_nh_basic(fib, src, 0, NHR_IFAIF, 0, &nh6) != 0) 533 return (0); 534 535 /* If ifp is provided, check for equality with route table. */ 536 if (ifp != NULL && ifp != nh6.nh_ifp) 537 return (0); 538 539 /* if no ifp provided, check if rtentry is not default route */ 540 if (ifp == NULL && (nh6.nh_flags & NHF_DEFAULT) != 0) 541 return (0); 542 543 /* or if this is a blackhole/reject route */ 544 if (ifp == NULL && (nh6.nh_flags & (NHF_REJECT|NHF_BLACKHOLE)) != 0) 545 return (0); 546 547 /* found valid route */ 548 return 1; 549 } 550 551 static int 552 is_icmp6_query(int icmp6_type) 553 { 554 if ((icmp6_type <= ICMP6_MAXTYPE) && 555 (icmp6_type == ICMP6_ECHO_REQUEST || 556 icmp6_type == ICMP6_MEMBERSHIP_QUERY || 557 icmp6_type == ICMP6_WRUREQUEST || 558 icmp6_type == ICMP6_FQDN_QUERY || 559 icmp6_type == ICMP6_NI_QUERY)) 560 return (1); 561 562 return (0); 563 } 564 565 static void 566 send_reject6(struct ip_fw_args *args, int code, u_int hlen, struct ip6_hdr *ip6) 567 { 568 struct mbuf *m; 569 570 m = args->m; 571 if (code == ICMP6_UNREACH_RST && args->f_id.proto == IPPROTO_TCP) { 572 struct tcphdr *tcp; 573 tcp = (struct tcphdr *)((char *)ip6 + hlen); 574 575 if ((tcp->th_flags & TH_RST) == 0) { 576 struct mbuf *m0; 577 m0 = ipfw_send_pkt(args->m, &(args->f_id), 578 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 579 tcp->th_flags | TH_RST); 580 if (m0 != NULL) 581 ip6_output(m0, NULL, NULL, 0, NULL, NULL, 582 NULL); 583 } 584 FREE_PKT(m); 585 } else if (code != ICMP6_UNREACH_RST) { /* Send an ICMPv6 unreach. */ 586 #if 0 587 /* 588 * Unlike above, the mbufs need to line up with the ip6 hdr, 589 * as the contents are read. We need to m_adj() the 590 * needed amount. 591 * The mbuf will however be thrown away so we can adjust it. 592 * Remember we did an m_pullup on it already so we 593 * can make some assumptions about contiguousness. 594 */ 595 if (args->L3offset) 596 m_adj(m, args->L3offset); 597 #endif 598 icmp6_error(m, ICMP6_DST_UNREACH, code, 0); 599 } else 600 FREE_PKT(m); 601 602 args->m = NULL; 603 } 604 605 #endif /* INET6 */ 606 607 608 /* 609 * sends a reject message, consuming the mbuf passed as an argument. 610 */ 611 static void 612 send_reject(struct ip_fw_args *args, int code, int iplen, struct ip *ip) 613 { 614 615 #if 0 616 /* XXX When ip is not guaranteed to be at mtod() we will 617 * need to account for this */ 618 * The mbuf will however be thrown away so we can adjust it. 619 * Remember we did an m_pullup on it already so we 620 * can make some assumptions about contiguousness. 621 */ 622 if (args->L3offset) 623 m_adj(m, args->L3offset); 624 #endif 625 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */ 626 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 627 } else if (args->f_id.proto == IPPROTO_TCP) { 628 struct tcphdr *const tcp = 629 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 630 if ( (tcp->th_flags & TH_RST) == 0) { 631 struct mbuf *m; 632 m = ipfw_send_pkt(args->m, &(args->f_id), 633 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 634 tcp->th_flags | TH_RST); 635 if (m != NULL) 636 ip_output(m, NULL, NULL, 0, NULL, NULL); 637 } 638 FREE_PKT(args->m); 639 } else 640 FREE_PKT(args->m); 641 args->m = NULL; 642 } 643 644 /* 645 * Support for uid/gid/jail lookup. These tests are expensive 646 * (because we may need to look into the list of active sockets) 647 * so we cache the results. ugid_lookupp is 0 if we have not 648 * yet done a lookup, 1 if we succeeded, and -1 if we tried 649 * and failed. The function always returns the match value. 650 * We could actually spare the variable and use *uc, setting 651 * it to '(void *)check_uidgid if we have no info, NULL if 652 * we tried and failed, or any other value if successful. 653 */ 654 static int 655 check_uidgid(ipfw_insn_u32 *insn, struct ip_fw_args *args, int *ugid_lookupp, 656 struct ucred **uc) 657 { 658 #if defined(USERSPACE) 659 return 0; // not supported in userspace 660 #else 661 #ifndef __FreeBSD__ 662 /* XXX */ 663 return cred_check(insn, proto, oif, 664 dst_ip, dst_port, src_ip, src_port, 665 (struct bsd_ucred *)uc, ugid_lookupp, ((struct mbuf *)inp)->m_skb); 666 #else /* FreeBSD */ 667 struct in_addr src_ip, dst_ip; 668 struct inpcbinfo *pi; 669 struct ipfw_flow_id *id; 670 struct inpcb *pcb, *inp; 671 struct ifnet *oif; 672 int lookupflags; 673 int match; 674 675 id = &args->f_id; 676 inp = args->inp; 677 oif = args->oif; 678 679 /* 680 * Check to see if the UDP or TCP stack supplied us with 681 * the PCB. If so, rather then holding a lock and looking 682 * up the PCB, we can use the one that was supplied. 683 */ 684 if (inp && *ugid_lookupp == 0) { 685 INP_LOCK_ASSERT(inp); 686 if (inp->inp_socket != NULL) { 687 *uc = crhold(inp->inp_cred); 688 *ugid_lookupp = 1; 689 } else 690 *ugid_lookupp = -1; 691 } 692 /* 693 * If we have already been here and the packet has no 694 * PCB entry associated with it, then we can safely 695 * assume that this is a no match. 696 */ 697 if (*ugid_lookupp == -1) 698 return (0); 699 if (id->proto == IPPROTO_TCP) { 700 lookupflags = 0; 701 pi = &V_tcbinfo; 702 } else if (id->proto == IPPROTO_UDP) { 703 lookupflags = INPLOOKUP_WILDCARD; 704 pi = &V_udbinfo; 705 } else 706 return 0; 707 lookupflags |= INPLOOKUP_RLOCKPCB; 708 match = 0; 709 if (*ugid_lookupp == 0) { 710 if (id->addr_type == 6) { 711 #ifdef INET6 712 if (oif == NULL) 713 pcb = in6_pcblookup_mbuf(pi, 714 &id->src_ip6, htons(id->src_port), 715 &id->dst_ip6, htons(id->dst_port), 716 lookupflags, oif, args->m); 717 else 718 pcb = in6_pcblookup_mbuf(pi, 719 &id->dst_ip6, htons(id->dst_port), 720 &id->src_ip6, htons(id->src_port), 721 lookupflags, oif, args->m); 722 #else 723 *ugid_lookupp = -1; 724 return (0); 725 #endif 726 } else { 727 src_ip.s_addr = htonl(id->src_ip); 728 dst_ip.s_addr = htonl(id->dst_ip); 729 if (oif == NULL) 730 pcb = in_pcblookup_mbuf(pi, 731 src_ip, htons(id->src_port), 732 dst_ip, htons(id->dst_port), 733 lookupflags, oif, args->m); 734 else 735 pcb = in_pcblookup_mbuf(pi, 736 dst_ip, htons(id->dst_port), 737 src_ip, htons(id->src_port), 738 lookupflags, oif, args->m); 739 } 740 if (pcb != NULL) { 741 INP_RLOCK_ASSERT(pcb); 742 *uc = crhold(pcb->inp_cred); 743 *ugid_lookupp = 1; 744 INP_RUNLOCK(pcb); 745 } 746 if (*ugid_lookupp == 0) { 747 /* 748 * We tried and failed, set the variable to -1 749 * so we will not try again on this packet. 750 */ 751 *ugid_lookupp = -1; 752 return (0); 753 } 754 } 755 if (insn->o.opcode == O_UID) 756 match = ((*uc)->cr_uid == (uid_t)insn->d[0]); 757 else if (insn->o.opcode == O_GID) 758 match = groupmember((gid_t)insn->d[0], *uc); 759 else if (insn->o.opcode == O_JAIL) 760 match = ((*uc)->cr_prison->pr_id == (int)insn->d[0]); 761 return (match); 762 #endif /* __FreeBSD__ */ 763 #endif /* not supported in userspace */ 764 } 765 766 /* 767 * Helper function to set args with info on the rule after the matching 768 * one. slot is precise, whereas we guess rule_id as they are 769 * assigned sequentially. 770 */ 771 static inline void 772 set_match(struct ip_fw_args *args, int slot, 773 struct ip_fw_chain *chain) 774 { 775 args->rule.chain_id = chain->id; 776 args->rule.slot = slot + 1; /* we use 0 as a marker */ 777 args->rule.rule_id = 1 + chain->map[slot]->id; 778 args->rule.rulenum = chain->map[slot]->rulenum; 779 } 780 781 #ifndef LINEAR_SKIPTO 782 /* 783 * Helper function to enable cached rule lookups using 784 * cached_id and cached_pos fields in ipfw rule. 785 */ 786 static int 787 jump_fast(struct ip_fw_chain *chain, struct ip_fw *f, int num, 788 int tablearg, int jump_backwards) 789 { 790 int f_pos; 791 792 /* If possible use cached f_pos (in f->cached_pos), 793 * whose version is written in f->cached_id 794 * (horrible hacks to avoid changing the ABI). 795 */ 796 if (num != IP_FW_TARG && f->cached_id == chain->id) 797 f_pos = f->cached_pos; 798 else { 799 int i = IP_FW_ARG_TABLEARG(chain, num, skipto); 800 /* make sure we do not jump backward */ 801 if (jump_backwards == 0 && i <= f->rulenum) 802 i = f->rulenum + 1; 803 if (chain->idxmap != NULL) 804 f_pos = chain->idxmap[i]; 805 else 806 f_pos = ipfw_find_rule(chain, i, 0); 807 /* update the cache */ 808 if (num != IP_FW_TARG) { 809 f->cached_id = chain->id; 810 f->cached_pos = f_pos; 811 } 812 } 813 814 return (f_pos); 815 } 816 #else 817 /* 818 * Helper function to enable real fast rule lookups. 819 */ 820 static int 821 jump_linear(struct ip_fw_chain *chain, struct ip_fw *f, int num, 822 int tablearg, int jump_backwards) 823 { 824 int f_pos; 825 826 num = IP_FW_ARG_TABLEARG(chain, num, skipto); 827 /* make sure we do not jump backward */ 828 if (jump_backwards == 0 && num <= f->rulenum) 829 num = f->rulenum + 1; 830 f_pos = chain->idxmap[num]; 831 832 return (f_pos); 833 } 834 #endif 835 836 #define TARG(k, f) IP_FW_ARG_TABLEARG(chain, k, f) 837 /* 838 * The main check routine for the firewall. 839 * 840 * All arguments are in args so we can modify them and return them 841 * back to the caller. 842 * 843 * Parameters: 844 * 845 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 846 * Starts with the IP header. 847 * args->eh (in) Mac header if present, NULL for layer3 packet. 848 * args->L3offset Number of bytes bypassed if we came from L2. 849 * e.g. often sizeof(eh) ** NOTYET ** 850 * args->oif Outgoing interface, NULL if packet is incoming. 851 * The incoming interface is in the mbuf. (in) 852 * args->divert_rule (in/out) 853 * Skip up to the first rule past this rule number; 854 * upon return, non-zero port number for divert or tee. 855 * 856 * args->rule Pointer to the last matching rule (in/out) 857 * args->next_hop Socket we are forwarding to (out). 858 * args->next_hop6 IPv6 next hop we are forwarding to (out). 859 * args->f_id Addresses grabbed from the packet (out) 860 * args->rule.info a cookie depending on rule action 861 * 862 * Return value: 863 * 864 * IP_FW_PASS the packet must be accepted 865 * IP_FW_DENY the packet must be dropped 866 * IP_FW_DIVERT divert packet, port in m_tag 867 * IP_FW_TEE tee packet, port in m_tag 868 * IP_FW_DUMMYNET to dummynet, pipe in args->cookie 869 * IP_FW_NETGRAPH into netgraph, cookie args->cookie 870 * args->rule contains the matching rule, 871 * args->rule.info has additional information. 872 * 873 */ 874 int 875 ipfw_chk(struct ip_fw_args *args) 876 { 877 878 /* 879 * Local variables holding state while processing a packet: 880 * 881 * IMPORTANT NOTE: to speed up the processing of rules, there 882 * are some assumption on the values of the variables, which 883 * are documented here. Should you change them, please check 884 * the implementation of the various instructions to make sure 885 * that they still work. 886 * 887 * args->eh The MAC header. It is non-null for a layer2 888 * packet, it is NULL for a layer-3 packet. 889 * **notyet** 890 * args->L3offset Offset in the packet to the L3 (IP or equiv.) header. 891 * 892 * m | args->m Pointer to the mbuf, as received from the caller. 893 * It may change if ipfw_chk() does an m_pullup, or if it 894 * consumes the packet because it calls send_reject(). 895 * XXX This has to change, so that ipfw_chk() never modifies 896 * or consumes the buffer. 897 * ip is the beginning of the ip(4 or 6) header. 898 * Calculated by adding the L3offset to the start of data. 899 * (Until we start using L3offset, the packet is 900 * supposed to start with the ip header). 901 */ 902 struct mbuf *m = args->m; 903 struct ip *ip = mtod(m, struct ip *); 904 905 /* 906 * For rules which contain uid/gid or jail constraints, cache 907 * a copy of the users credentials after the pcb lookup has been 908 * executed. This will speed up the processing of rules with 909 * these types of constraints, as well as decrease contention 910 * on pcb related locks. 911 */ 912 #ifndef __FreeBSD__ 913 struct bsd_ucred ucred_cache; 914 #else 915 struct ucred *ucred_cache = NULL; 916 #endif 917 int ucred_lookup = 0; 918 919 /* 920 * oif | args->oif If NULL, ipfw_chk has been called on the 921 * inbound path (ether_input, ip_input). 922 * If non-NULL, ipfw_chk has been called on the outbound path 923 * (ether_output, ip_output). 924 */ 925 struct ifnet *oif = args->oif; 926 927 int f_pos = 0; /* index of current rule in the array */ 928 int retval = 0; 929 930 /* 931 * hlen The length of the IP header. 932 */ 933 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 934 935 /* 936 * offset The offset of a fragment. offset != 0 means that 937 * we have a fragment at this offset of an IPv4 packet. 938 * offset == 0 means that (if this is an IPv4 packet) 939 * this is the first or only fragment. 940 * For IPv6 offset|ip6f_mf == 0 means there is no Fragment Header 941 * or there is a single packet fragment (fragment header added 942 * without needed). We will treat a single packet fragment as if 943 * there was no fragment header (or log/block depending on the 944 * V_fw_permit_single_frag6 sysctl setting). 945 */ 946 u_short offset = 0; 947 u_short ip6f_mf = 0; 948 949 /* 950 * Local copies of addresses. They are only valid if we have 951 * an IP packet. 952 * 953 * proto The protocol. Set to 0 for non-ip packets, 954 * or to the protocol read from the packet otherwise. 955 * proto != 0 means that we have an IPv4 packet. 956 * 957 * src_port, dst_port port numbers, in HOST format. Only 958 * valid for TCP and UDP packets. 959 * 960 * src_ip, dst_ip ip addresses, in NETWORK format. 961 * Only valid for IPv4 packets. 962 */ 963 uint8_t proto; 964 uint16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 965 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 966 uint16_t iplen=0; 967 int pktlen; 968 uint16_t etype = 0; /* Host order stored ether type */ 969 970 /* 971 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 972 * MATCH_NONE when checked and not matched (q = NULL), 973 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 974 */ 975 int dyn_dir = MATCH_UNKNOWN; 976 uint16_t dyn_name = 0; 977 ipfw_dyn_rule *q = NULL; 978 struct ip_fw_chain *chain = &V_layer3_chain; 979 980 /* 981 * We store in ulp a pointer to the upper layer protocol header. 982 * In the ipv4 case this is easy to determine from the header, 983 * but for ipv6 we might have some additional headers in the middle. 984 * ulp is NULL if not found. 985 */ 986 void *ulp = NULL; /* upper layer protocol pointer. */ 987 988 /* XXX ipv6 variables */ 989 int is_ipv6 = 0; 990 uint8_t icmp6_type = 0; 991 uint16_t ext_hd = 0; /* bits vector for extension header filtering */ 992 /* end of ipv6 variables */ 993 994 int is_ipv4 = 0; 995 996 int done = 0; /* flag to exit the outer loop */ 997 998 if (m->m_flags & M_SKIP_FIREWALL || (! V_ipfw_vnet_ready)) 999 return (IP_FW_PASS); /* accept */ 1000 1001 dst_ip.s_addr = 0; /* make sure it is initialized */ 1002 src_ip.s_addr = 0; /* make sure it is initialized */ 1003 pktlen = m->m_pkthdr.len; 1004 args->f_id.fib = M_GETFIB(m); /* note mbuf not altered) */ 1005 proto = args->f_id.proto = 0; /* mark f_id invalid */ 1006 /* XXX 0 is a valid proto: IP/IPv6 Hop-by-Hop Option */ 1007 1008 /* 1009 * PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous, 1010 * then it sets p to point at the offset "len" in the mbuf. WARNING: the 1011 * pointer might become stale after other pullups (but we never use it 1012 * this way). 1013 */ 1014 #define PULLUP_TO(_len, p, T) PULLUP_LEN(_len, p, sizeof(T)) 1015 #define PULLUP_LEN(_len, p, T) \ 1016 do { \ 1017 int x = (_len) + T; \ 1018 if ((m)->m_len < x) { \ 1019 args->m = m = m_pullup(m, x); \ 1020 if (m == NULL) \ 1021 goto pullup_failed; \ 1022 } \ 1023 p = (mtod(m, char *) + (_len)); \ 1024 } while (0) 1025 1026 /* 1027 * if we have an ether header, 1028 */ 1029 if (args->eh) 1030 etype = ntohs(args->eh->ether_type); 1031 1032 /* Identify IP packets and fill up variables. */ 1033 if (pktlen >= sizeof(struct ip6_hdr) && 1034 (args->eh == NULL || etype == ETHERTYPE_IPV6) && ip->ip_v == 6) { 1035 struct ip6_hdr *ip6 = (struct ip6_hdr *)ip; 1036 is_ipv6 = 1; 1037 args->f_id.addr_type = 6; 1038 hlen = sizeof(struct ip6_hdr); 1039 proto = ip6->ip6_nxt; 1040 1041 /* Search extension headers to find upper layer protocols */ 1042 while (ulp == NULL && offset == 0) { 1043 switch (proto) { 1044 case IPPROTO_ICMPV6: 1045 PULLUP_TO(hlen, ulp, struct icmp6_hdr); 1046 icmp6_type = ICMP6(ulp)->icmp6_type; 1047 break; 1048 1049 case IPPROTO_TCP: 1050 PULLUP_TO(hlen, ulp, struct tcphdr); 1051 dst_port = TCP(ulp)->th_dport; 1052 src_port = TCP(ulp)->th_sport; 1053 /* save flags for dynamic rules */ 1054 args->f_id._flags = TCP(ulp)->th_flags; 1055 break; 1056 1057 case IPPROTO_SCTP: 1058 PULLUP_TO(hlen, ulp, struct sctphdr); 1059 src_port = SCTP(ulp)->src_port; 1060 dst_port = SCTP(ulp)->dest_port; 1061 break; 1062 1063 case IPPROTO_UDP: 1064 PULLUP_TO(hlen, ulp, struct udphdr); 1065 dst_port = UDP(ulp)->uh_dport; 1066 src_port = UDP(ulp)->uh_sport; 1067 break; 1068 1069 case IPPROTO_HOPOPTS: /* RFC 2460 */ 1070 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1071 ext_hd |= EXT_HOPOPTS; 1072 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1073 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1074 ulp = NULL; 1075 break; 1076 1077 case IPPROTO_ROUTING: /* RFC 2460 */ 1078 PULLUP_TO(hlen, ulp, struct ip6_rthdr); 1079 switch (((struct ip6_rthdr *)ulp)->ip6r_type) { 1080 case 0: 1081 ext_hd |= EXT_RTHDR0; 1082 break; 1083 case 2: 1084 ext_hd |= EXT_RTHDR2; 1085 break; 1086 default: 1087 if (V_fw_verbose) 1088 printf("IPFW2: IPV6 - Unknown " 1089 "Routing Header type(%d)\n", 1090 ((struct ip6_rthdr *) 1091 ulp)->ip6r_type); 1092 if (V_fw_deny_unknown_exthdrs) 1093 return (IP_FW_DENY); 1094 break; 1095 } 1096 ext_hd |= EXT_ROUTING; 1097 hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3; 1098 proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt; 1099 ulp = NULL; 1100 break; 1101 1102 case IPPROTO_FRAGMENT: /* RFC 2460 */ 1103 PULLUP_TO(hlen, ulp, struct ip6_frag); 1104 ext_hd |= EXT_FRAGMENT; 1105 hlen += sizeof (struct ip6_frag); 1106 proto = ((struct ip6_frag *)ulp)->ip6f_nxt; 1107 offset = ((struct ip6_frag *)ulp)->ip6f_offlg & 1108 IP6F_OFF_MASK; 1109 ip6f_mf = ((struct ip6_frag *)ulp)->ip6f_offlg & 1110 IP6F_MORE_FRAG; 1111 if (V_fw_permit_single_frag6 == 0 && 1112 offset == 0 && ip6f_mf == 0) { 1113 if (V_fw_verbose) 1114 printf("IPFW2: IPV6 - Invalid " 1115 "Fragment Header\n"); 1116 if (V_fw_deny_unknown_exthdrs) 1117 return (IP_FW_DENY); 1118 break; 1119 } 1120 args->f_id.extra = 1121 ntohl(((struct ip6_frag *)ulp)->ip6f_ident); 1122 ulp = NULL; 1123 break; 1124 1125 case IPPROTO_DSTOPTS: /* RFC 2460 */ 1126 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1127 ext_hd |= EXT_DSTOPTS; 1128 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1129 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1130 ulp = NULL; 1131 break; 1132 1133 case IPPROTO_AH: /* RFC 2402 */ 1134 PULLUP_TO(hlen, ulp, struct ip6_ext); 1135 ext_hd |= EXT_AH; 1136 hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2; 1137 proto = ((struct ip6_ext *)ulp)->ip6e_nxt; 1138 ulp = NULL; 1139 break; 1140 1141 case IPPROTO_ESP: /* RFC 2406 */ 1142 PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */ 1143 /* Anything past Seq# is variable length and 1144 * data past this ext. header is encrypted. */ 1145 ext_hd |= EXT_ESP; 1146 break; 1147 1148 case IPPROTO_NONE: /* RFC 2460 */ 1149 /* 1150 * Packet ends here, and IPv6 header has 1151 * already been pulled up. If ip6e_len!=0 1152 * then octets must be ignored. 1153 */ 1154 ulp = ip; /* non-NULL to get out of loop. */ 1155 break; 1156 1157 case IPPROTO_OSPFIGP: 1158 /* XXX OSPF header check? */ 1159 PULLUP_TO(hlen, ulp, struct ip6_ext); 1160 break; 1161 1162 case IPPROTO_PIM: 1163 /* XXX PIM header check? */ 1164 PULLUP_TO(hlen, ulp, struct pim); 1165 break; 1166 1167 case IPPROTO_GRE: /* RFC 1701 */ 1168 /* XXX GRE header check? */ 1169 PULLUP_TO(hlen, ulp, struct grehdr); 1170 break; 1171 1172 case IPPROTO_CARP: 1173 PULLUP_TO(hlen, ulp, struct carp_header); 1174 if (((struct carp_header *)ulp)->carp_version != 1175 CARP_VERSION) 1176 return (IP_FW_DENY); 1177 if (((struct carp_header *)ulp)->carp_type != 1178 CARP_ADVERTISEMENT) 1179 return (IP_FW_DENY); 1180 break; 1181 1182 case IPPROTO_IPV6: /* RFC 2893 */ 1183 PULLUP_TO(hlen, ulp, struct ip6_hdr); 1184 break; 1185 1186 case IPPROTO_IPV4: /* RFC 2893 */ 1187 PULLUP_TO(hlen, ulp, struct ip); 1188 break; 1189 1190 default: 1191 if (V_fw_verbose) 1192 printf("IPFW2: IPV6 - Unknown " 1193 "Extension Header(%d), ext_hd=%x\n", 1194 proto, ext_hd); 1195 if (V_fw_deny_unknown_exthdrs) 1196 return (IP_FW_DENY); 1197 PULLUP_TO(hlen, ulp, struct ip6_ext); 1198 break; 1199 } /*switch */ 1200 } 1201 ip = mtod(m, struct ip *); 1202 ip6 = (struct ip6_hdr *)ip; 1203 args->f_id.src_ip6 = ip6->ip6_src; 1204 args->f_id.dst_ip6 = ip6->ip6_dst; 1205 args->f_id.src_ip = 0; 1206 args->f_id.dst_ip = 0; 1207 args->f_id.flow_id6 = ntohl(ip6->ip6_flow); 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 pktlen = iplen < pktlen ? iplen : pktlen; 1223 1224 if (offset == 0) { 1225 switch (proto) { 1226 case IPPROTO_TCP: 1227 PULLUP_TO(hlen, ulp, struct tcphdr); 1228 dst_port = TCP(ulp)->th_dport; 1229 src_port = TCP(ulp)->th_sport; 1230 /* save flags for dynamic rules */ 1231 args->f_id._flags = TCP(ulp)->th_flags; 1232 break; 1233 1234 case IPPROTO_SCTP: 1235 PULLUP_TO(hlen, ulp, struct sctphdr); 1236 src_port = SCTP(ulp)->src_port; 1237 dst_port = SCTP(ulp)->dest_port; 1238 break; 1239 1240 case IPPROTO_UDP: 1241 PULLUP_TO(hlen, ulp, struct udphdr); 1242 dst_port = UDP(ulp)->uh_dport; 1243 src_port = UDP(ulp)->uh_sport; 1244 break; 1245 1246 case IPPROTO_ICMP: 1247 PULLUP_TO(hlen, ulp, struct icmphdr); 1248 //args->f_id.flags = ICMP(ulp)->icmp_type; 1249 break; 1250 1251 default: 1252 break; 1253 } 1254 } 1255 1256 ip = mtod(m, struct ip *); 1257 args->f_id.src_ip = ntohl(src_ip.s_addr); 1258 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1259 } 1260 #undef PULLUP_TO 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 1775 tcp = TCP(ulp); 1776 x = iplen - 1777 ((ip->ip_hl + tcp->th_off) << 2); 1778 if (cmdlen == 1) { 1779 match = (cmd->arg1 == x); 1780 break; 1781 } 1782 /* otherwise we have ranges */ 1783 p = ((ipfw_insn_u16 *)cmd)->ports; 1784 i = cmdlen - 1; 1785 for (; !match && i>0; i--, p += 2) 1786 match = (x >= p[0] && x <= p[1]); 1787 } 1788 break; 1789 1790 case O_TCPFLAGS: 1791 match = (proto == IPPROTO_TCP && offset == 0 && 1792 flags_match(cmd, TCP(ulp)->th_flags)); 1793 break; 1794 1795 case O_TCPOPTS: 1796 if (proto == IPPROTO_TCP && offset == 0 && ulp){ 1797 PULLUP_LEN(hlen, ulp, 1798 (TCP(ulp)->th_off << 2)); 1799 match = tcpopts_match(TCP(ulp), cmd); 1800 } 1801 break; 1802 1803 case O_TCPSEQ: 1804 match = (proto == IPPROTO_TCP && offset == 0 && 1805 ((ipfw_insn_u32 *)cmd)->d[0] == 1806 TCP(ulp)->th_seq); 1807 break; 1808 1809 case O_TCPACK: 1810 match = (proto == IPPROTO_TCP && offset == 0 && 1811 ((ipfw_insn_u32 *)cmd)->d[0] == 1812 TCP(ulp)->th_ack); 1813 break; 1814 1815 case O_TCPWIN: 1816 if (proto == IPPROTO_TCP && offset == 0) { 1817 uint16_t x; 1818 uint16_t *p; 1819 int i; 1820 1821 x = ntohs(TCP(ulp)->th_win); 1822 if (cmdlen == 1) { 1823 match = (cmd->arg1 == x); 1824 break; 1825 } 1826 /* Otherwise we have ranges. */ 1827 p = ((ipfw_insn_u16 *)cmd)->ports; 1828 i = cmdlen - 1; 1829 for (; !match && i > 0; i--, p += 2) 1830 match = (x >= p[0] && x <= p[1]); 1831 } 1832 break; 1833 1834 case O_ESTAB: 1835 /* reject packets which have SYN only */ 1836 /* XXX should i also check for TH_ACK ? */ 1837 match = (proto == IPPROTO_TCP && offset == 0 && 1838 (TCP(ulp)->th_flags & 1839 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 1840 break; 1841 1842 case O_ALTQ: { 1843 struct pf_mtag *at; 1844 struct m_tag *mtag; 1845 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 1846 1847 /* 1848 * ALTQ uses mbuf tags from another 1849 * packet filtering system - pf(4). 1850 * We allocate a tag in its format 1851 * and fill it in, pretending to be pf(4). 1852 */ 1853 match = 1; 1854 at = pf_find_mtag(m); 1855 if (at != NULL && at->qid != 0) 1856 break; 1857 mtag = m_tag_get(PACKET_TAG_PF, 1858 sizeof(struct pf_mtag), M_NOWAIT | M_ZERO); 1859 if (mtag == NULL) { 1860 /* 1861 * Let the packet fall back to the 1862 * default ALTQ. 1863 */ 1864 break; 1865 } 1866 m_tag_prepend(m, mtag); 1867 at = (struct pf_mtag *)(mtag + 1); 1868 at->qid = altq->qid; 1869 at->hdr = ip; 1870 break; 1871 } 1872 1873 case O_LOG: 1874 ipfw_log(chain, f, hlen, args, m, 1875 oif, offset | ip6f_mf, tablearg, ip); 1876 match = 1; 1877 break; 1878 1879 case O_PROB: 1880 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 1881 break; 1882 1883 case O_VERREVPATH: 1884 /* Outgoing packets automatically pass/match */ 1885 match = ((oif != NULL) || 1886 (m->m_pkthdr.rcvif == NULL) || 1887 ( 1888 #ifdef INET6 1889 is_ipv6 ? 1890 verify_path6(&(args->f_id.src_ip6), 1891 m->m_pkthdr.rcvif, args->f_id.fib) : 1892 #endif 1893 verify_path(src_ip, m->m_pkthdr.rcvif, 1894 args->f_id.fib))); 1895 break; 1896 1897 case O_VERSRCREACH: 1898 /* Outgoing packets automatically pass/match */ 1899 match = (hlen > 0 && ((oif != NULL) || 1900 #ifdef INET6 1901 is_ipv6 ? 1902 verify_path6(&(args->f_id.src_ip6), 1903 NULL, args->f_id.fib) : 1904 #endif 1905 verify_path(src_ip, NULL, args->f_id.fib))); 1906 break; 1907 1908 case O_ANTISPOOF: 1909 /* Outgoing packets automatically pass/match */ 1910 if (oif == NULL && hlen > 0 && 1911 ( (is_ipv4 && in_localaddr(src_ip)) 1912 #ifdef INET6 1913 || (is_ipv6 && 1914 in6_localaddr(&(args->f_id.src_ip6))) 1915 #endif 1916 )) 1917 match = 1918 #ifdef INET6 1919 is_ipv6 ? verify_path6( 1920 &(args->f_id.src_ip6), 1921 m->m_pkthdr.rcvif, 1922 args->f_id.fib) : 1923 #endif 1924 verify_path(src_ip, 1925 m->m_pkthdr.rcvif, 1926 args->f_id.fib); 1927 else 1928 match = 1; 1929 break; 1930 1931 case O_IPSEC: 1932 #ifdef IPSEC 1933 match = (m_tag_find(m, 1934 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 1935 #endif 1936 /* otherwise no match */ 1937 break; 1938 1939 #ifdef INET6 1940 case O_IP6_SRC: 1941 match = is_ipv6 && 1942 IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6, 1943 &((ipfw_insn_ip6 *)cmd)->addr6); 1944 break; 1945 1946 case O_IP6_DST: 1947 match = is_ipv6 && 1948 IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6, 1949 &((ipfw_insn_ip6 *)cmd)->addr6); 1950 break; 1951 case O_IP6_SRC_MASK: 1952 case O_IP6_DST_MASK: 1953 if (is_ipv6) { 1954 int i = cmdlen - 1; 1955 struct in6_addr p; 1956 struct in6_addr *d = 1957 &((ipfw_insn_ip6 *)cmd)->addr6; 1958 1959 for (; !match && i > 0; d += 2, 1960 i -= F_INSN_SIZE(struct in6_addr) 1961 * 2) { 1962 p = (cmd->opcode == 1963 O_IP6_SRC_MASK) ? 1964 args->f_id.src_ip6: 1965 args->f_id.dst_ip6; 1966 APPLY_MASK(&p, &d[1]); 1967 match = 1968 IN6_ARE_ADDR_EQUAL(&d[0], 1969 &p); 1970 } 1971 } 1972 break; 1973 1974 case O_FLOW6ID: 1975 match = is_ipv6 && 1976 flow6id_match(args->f_id.flow_id6, 1977 (ipfw_insn_u32 *) cmd); 1978 break; 1979 1980 case O_EXT_HDR: 1981 match = is_ipv6 && 1982 (ext_hd & ((ipfw_insn *) cmd)->arg1); 1983 break; 1984 1985 case O_IP6: 1986 match = is_ipv6; 1987 break; 1988 #endif 1989 1990 case O_IP4: 1991 match = is_ipv4; 1992 break; 1993 1994 case O_TAG: { 1995 struct m_tag *mtag; 1996 uint32_t tag = TARG(cmd->arg1, tag); 1997 1998 /* Packet is already tagged with this tag? */ 1999 mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL); 2000 2001 /* We have `untag' action when F_NOT flag is 2002 * present. And we must remove this mtag from 2003 * mbuf and reset `match' to zero (`match' will 2004 * be inversed later). 2005 * Otherwise we should allocate new mtag and 2006 * push it into mbuf. 2007 */ 2008 if (cmd->len & F_NOT) { /* `untag' action */ 2009 if (mtag != NULL) 2010 m_tag_delete(m, mtag); 2011 match = 0; 2012 } else { 2013 if (mtag == NULL) { 2014 mtag = m_tag_alloc( MTAG_IPFW, 2015 tag, 0, M_NOWAIT); 2016 if (mtag != NULL) 2017 m_tag_prepend(m, mtag); 2018 } 2019 match = 1; 2020 } 2021 break; 2022 } 2023 2024 case O_FIB: /* try match the specified fib */ 2025 if (args->f_id.fib == cmd->arg1) 2026 match = 1; 2027 break; 2028 2029 case O_SOCKARG: { 2030 #ifndef USERSPACE /* not supported in userspace */ 2031 struct inpcb *inp = args->inp; 2032 struct inpcbinfo *pi; 2033 2034 if (is_ipv6) /* XXX can we remove this ? */ 2035 break; 2036 2037 if (proto == IPPROTO_TCP) 2038 pi = &V_tcbinfo; 2039 else if (proto == IPPROTO_UDP) 2040 pi = &V_udbinfo; 2041 else 2042 break; 2043 2044 /* 2045 * XXXRW: so_user_cookie should almost 2046 * certainly be inp_user_cookie? 2047 */ 2048 2049 /* For incoming packet, lookup up the 2050 inpcb using the src/dest ip/port tuple */ 2051 if (inp == NULL) { 2052 inp = in_pcblookup(pi, 2053 src_ip, htons(src_port), 2054 dst_ip, htons(dst_port), 2055 INPLOOKUP_RLOCKPCB, NULL); 2056 if (inp != NULL) { 2057 tablearg = 2058 inp->inp_socket->so_user_cookie; 2059 if (tablearg) 2060 match = 1; 2061 INP_RUNLOCK(inp); 2062 } 2063 } else { 2064 if (inp->inp_socket) { 2065 tablearg = 2066 inp->inp_socket->so_user_cookie; 2067 if (tablearg) 2068 match = 1; 2069 } 2070 } 2071 #endif /* !USERSPACE */ 2072 break; 2073 } 2074 2075 case O_TAGGED: { 2076 struct m_tag *mtag; 2077 uint32_t tag = TARG(cmd->arg1, tag); 2078 2079 if (cmdlen == 1) { 2080 match = m_tag_locate(m, MTAG_IPFW, 2081 tag, NULL) != NULL; 2082 break; 2083 } 2084 2085 /* we have ranges */ 2086 for (mtag = m_tag_first(m); 2087 mtag != NULL && !match; 2088 mtag = m_tag_next(m, mtag)) { 2089 uint16_t *p; 2090 int i; 2091 2092 if (mtag->m_tag_cookie != MTAG_IPFW) 2093 continue; 2094 2095 p = ((ipfw_insn_u16 *)cmd)->ports; 2096 i = cmdlen - 1; 2097 for(; !match && i > 0; i--, p += 2) 2098 match = 2099 mtag->m_tag_id >= p[0] && 2100 mtag->m_tag_id <= p[1]; 2101 } 2102 break; 2103 } 2104 2105 /* 2106 * The second set of opcodes represents 'actions', 2107 * i.e. the terminal part of a rule once the packet 2108 * matches all previous patterns. 2109 * Typically there is only one action for each rule, 2110 * and the opcode is stored at the end of the rule 2111 * (but there are exceptions -- see below). 2112 * 2113 * In general, here we set retval and terminate the 2114 * outer loop (would be a 'break 3' in some language, 2115 * but we need to set l=0, done=1) 2116 * 2117 * Exceptions: 2118 * O_COUNT and O_SKIPTO actions: 2119 * instead of terminating, we jump to the next rule 2120 * (setting l=0), or to the SKIPTO target (setting 2121 * f/f_len, cmd and l as needed), respectively. 2122 * 2123 * O_TAG, O_LOG and O_ALTQ action parameters: 2124 * perform some action and set match = 1; 2125 * 2126 * O_LIMIT and O_KEEP_STATE: these opcodes are 2127 * not real 'actions', and are stored right 2128 * before the 'action' part of the rule. 2129 * These opcodes try to install an entry in the 2130 * state tables; if successful, we continue with 2131 * the next opcode (match=1; break;), otherwise 2132 * the packet must be dropped (set retval, 2133 * break loops with l=0, done=1) 2134 * 2135 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 2136 * cause a lookup of the state table, and a jump 2137 * to the 'action' part of the parent rule 2138 * if an entry is found, or 2139 * (CHECK_STATE only) a jump to the next rule if 2140 * the entry is not found. 2141 * The result of the lookup is cached so that 2142 * further instances of these opcodes become NOPs. 2143 * The jump to the next rule is done by setting 2144 * l=0, cmdlen=0. 2145 */ 2146 case O_LIMIT: 2147 case O_KEEP_STATE: 2148 if (ipfw_install_state(chain, f, 2149 (ipfw_insn_limit *)cmd, args, tablearg)) { 2150 /* error or limit violation */ 2151 retval = IP_FW_DENY; 2152 l = 0; /* exit inner loop */ 2153 done = 1; /* exit outer loop */ 2154 } 2155 match = 1; 2156 break; 2157 2158 case O_PROBE_STATE: 2159 case O_CHECK_STATE: 2160 /* 2161 * dynamic rules are checked at the first 2162 * keep-state or check-state occurrence, 2163 * with the result being stored in dyn_dir 2164 * and dyn_name. 2165 * The compiler introduces a PROBE_STATE 2166 * instruction for us when we have a 2167 * KEEP_STATE (because PROBE_STATE needs 2168 * to be run first). 2169 * 2170 * (dyn_dir == MATCH_UNKNOWN) means this is 2171 * first lookup for such f_id. Do lookup. 2172 * 2173 * (dyn_dir != MATCH_UNKNOWN && 2174 * dyn_name != 0 && dyn_name != cmd->arg1) 2175 * means previous lookup didn't find dynamic 2176 * rule for specific state name and current 2177 * lookup will search rule with another state 2178 * name. Redo lookup. 2179 * 2180 * (dyn_dir != MATCH_UNKNOWN && dyn_name == 0) 2181 * means previous lookup was for `any' name 2182 * and it didn't find rule. No need to do 2183 * lookup again. 2184 */ 2185 if ((dyn_dir == MATCH_UNKNOWN || 2186 (dyn_name != 0 && 2187 dyn_name != cmd->arg1)) && 2188 (q = ipfw_lookup_dyn_rule(&args->f_id, 2189 &dyn_dir, proto == IPPROTO_TCP ? 2190 TCP(ulp): NULL, 2191 (dyn_name = cmd->arg1))) != NULL) { 2192 /* 2193 * Found dynamic entry, update stats 2194 * and jump to the 'action' part of 2195 * the parent rule by setting 2196 * f, cmd, l and clearing cmdlen. 2197 */ 2198 IPFW_INC_DYN_COUNTER(q, pktlen); 2199 /* XXX we would like to have f_pos 2200 * readily accessible in the dynamic 2201 * rule, instead of having to 2202 * lookup q->rule. 2203 */ 2204 f = q->rule; 2205 f_pos = ipfw_find_rule(chain, 2206 f->rulenum, f->id); 2207 cmd = ACTION_PTR(f); 2208 l = f->cmd_len - f->act_ofs; 2209 ipfw_dyn_unlock(q); 2210 cmdlen = 0; 2211 match = 1; 2212 break; 2213 } 2214 /* 2215 * Dynamic entry not found. If CHECK_STATE, 2216 * skip to next rule, if PROBE_STATE just 2217 * ignore and continue with next opcode. 2218 */ 2219 if (cmd->opcode == O_CHECK_STATE) 2220 l = 0; /* exit inner loop */ 2221 match = 1; 2222 break; 2223 2224 case O_ACCEPT: 2225 retval = 0; /* accept */ 2226 l = 0; /* exit inner loop */ 2227 done = 1; /* exit outer loop */ 2228 break; 2229 2230 case O_PIPE: 2231 case O_QUEUE: 2232 set_match(args, f_pos, chain); 2233 args->rule.info = TARG(cmd->arg1, pipe); 2234 if (cmd->opcode == O_PIPE) 2235 args->rule.info |= IPFW_IS_PIPE; 2236 if (V_fw_one_pass) 2237 args->rule.info |= IPFW_ONEPASS; 2238 retval = IP_FW_DUMMYNET; 2239 l = 0; /* exit inner loop */ 2240 done = 1; /* exit outer loop */ 2241 break; 2242 2243 case O_DIVERT: 2244 case O_TEE: 2245 if (args->eh) /* not on layer 2 */ 2246 break; 2247 /* otherwise this is terminal */ 2248 l = 0; /* exit inner loop */ 2249 done = 1; /* exit outer loop */ 2250 retval = (cmd->opcode == O_DIVERT) ? 2251 IP_FW_DIVERT : IP_FW_TEE; 2252 set_match(args, f_pos, chain); 2253 args->rule.info = TARG(cmd->arg1, divert); 2254 break; 2255 2256 case O_COUNT: 2257 IPFW_INC_RULE_COUNTER(f, pktlen); 2258 l = 0; /* exit inner loop */ 2259 break; 2260 2261 case O_SKIPTO: 2262 IPFW_INC_RULE_COUNTER(f, pktlen); 2263 f_pos = JUMP(chain, f, cmd->arg1, tablearg, 0); 2264 /* 2265 * Skip disabled rules, and re-enter 2266 * the inner loop with the correct 2267 * f_pos, f, l and cmd. 2268 * Also clear cmdlen and skip_or 2269 */ 2270 for (; f_pos < chain->n_rules - 1 && 2271 (V_set_disable & 2272 (1 << chain->map[f_pos]->set)); 2273 f_pos++) 2274 ; 2275 /* Re-enter the inner loop at the skipto rule. */ 2276 f = chain->map[f_pos]; 2277 l = f->cmd_len; 2278 cmd = f->cmd; 2279 match = 1; 2280 cmdlen = 0; 2281 skip_or = 0; 2282 continue; 2283 break; /* not reached */ 2284 2285 case O_CALLRETURN: { 2286 /* 2287 * Implementation of `subroutine' call/return, 2288 * in the stack carried in an mbuf tag. This 2289 * is different from `skipto' in that any call 2290 * address is possible (`skipto' must prevent 2291 * backward jumps to avoid endless loops). 2292 * We have `return' action when F_NOT flag is 2293 * present. The `m_tag_id' field is used as 2294 * stack pointer. 2295 */ 2296 struct m_tag *mtag; 2297 uint16_t jmpto, *stack; 2298 2299 #define IS_CALL ((cmd->len & F_NOT) == 0) 2300 #define IS_RETURN ((cmd->len & F_NOT) != 0) 2301 /* 2302 * Hand-rolled version of m_tag_locate() with 2303 * wildcard `type'. 2304 * If not already tagged, allocate new tag. 2305 */ 2306 mtag = m_tag_first(m); 2307 while (mtag != NULL) { 2308 if (mtag->m_tag_cookie == 2309 MTAG_IPFW_CALL) 2310 break; 2311 mtag = m_tag_next(m, mtag); 2312 } 2313 if (mtag == NULL && IS_CALL) { 2314 mtag = m_tag_alloc(MTAG_IPFW_CALL, 0, 2315 IPFW_CALLSTACK_SIZE * 2316 sizeof(uint16_t), M_NOWAIT); 2317 if (mtag != NULL) 2318 m_tag_prepend(m, mtag); 2319 } 2320 2321 /* 2322 * On error both `call' and `return' just 2323 * continue with next rule. 2324 */ 2325 if (IS_RETURN && (mtag == NULL || 2326 mtag->m_tag_id == 0)) { 2327 l = 0; /* exit inner loop */ 2328 break; 2329 } 2330 if (IS_CALL && (mtag == NULL || 2331 mtag->m_tag_id >= IPFW_CALLSTACK_SIZE)) { 2332 printf("ipfw: call stack error, " 2333 "go to next rule\n"); 2334 l = 0; /* exit inner loop */ 2335 break; 2336 } 2337 2338 IPFW_INC_RULE_COUNTER(f, pktlen); 2339 stack = (uint16_t *)(mtag + 1); 2340 2341 /* 2342 * The `call' action may use cached f_pos 2343 * (in f->next_rule), whose version is written 2344 * in f->next_rule. 2345 * The `return' action, however, doesn't have 2346 * fixed jump address in cmd->arg1 and can't use 2347 * cache. 2348 */ 2349 if (IS_CALL) { 2350 stack[mtag->m_tag_id] = f->rulenum; 2351 mtag->m_tag_id++; 2352 f_pos = JUMP(chain, f, cmd->arg1, 2353 tablearg, 1); 2354 } else { /* `return' action */ 2355 mtag->m_tag_id--; 2356 jmpto = stack[mtag->m_tag_id] + 1; 2357 f_pos = ipfw_find_rule(chain, jmpto, 0); 2358 } 2359 2360 /* 2361 * Skip disabled rules, and re-enter 2362 * the inner loop with the correct 2363 * f_pos, f, l and cmd. 2364 * Also clear cmdlen and skip_or 2365 */ 2366 for (; f_pos < chain->n_rules - 1 && 2367 (V_set_disable & 2368 (1 << chain->map[f_pos]->set)); f_pos++) 2369 ; 2370 /* Re-enter the inner loop at the dest rule. */ 2371 f = chain->map[f_pos]; 2372 l = f->cmd_len; 2373 cmd = f->cmd; 2374 cmdlen = 0; 2375 skip_or = 0; 2376 continue; 2377 break; /* NOTREACHED */ 2378 } 2379 #undef IS_CALL 2380 #undef IS_RETURN 2381 2382 case O_REJECT: 2383 /* 2384 * Drop the packet and send a reject notice 2385 * if the packet is not ICMP (or is an ICMP 2386 * query), and it is not multicast/broadcast. 2387 */ 2388 if (hlen > 0 && is_ipv4 && offset == 0 && 2389 (proto != IPPROTO_ICMP || 2390 is_icmp_query(ICMP(ulp))) && 2391 !(m->m_flags & (M_BCAST|M_MCAST)) && 2392 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2393 send_reject(args, cmd->arg1, iplen, ip); 2394 m = args->m; 2395 } 2396 /* FALLTHROUGH */ 2397 #ifdef INET6 2398 case O_UNREACH6: 2399 if (hlen > 0 && is_ipv6 && 2400 ((offset & IP6F_OFF_MASK) == 0) && 2401 (proto != IPPROTO_ICMPV6 || 2402 (is_icmp6_query(icmp6_type) == 1)) && 2403 !(m->m_flags & (M_BCAST|M_MCAST)) && 2404 !IN6_IS_ADDR_MULTICAST(&args->f_id.dst_ip6)) { 2405 send_reject6( 2406 args, cmd->arg1, hlen, 2407 (struct ip6_hdr *)ip); 2408 m = args->m; 2409 } 2410 /* FALLTHROUGH */ 2411 #endif 2412 case O_DENY: 2413 retval = IP_FW_DENY; 2414 l = 0; /* exit inner loop */ 2415 done = 1; /* exit outer loop */ 2416 break; 2417 2418 case O_FORWARD_IP: 2419 if (args->eh) /* not valid on layer2 pkts */ 2420 break; 2421 if (q == NULL || q->rule != f || 2422 dyn_dir == MATCH_FORWARD) { 2423 struct sockaddr_in *sa; 2424 2425 sa = &(((ipfw_insn_sa *)cmd)->sa); 2426 if (sa->sin_addr.s_addr == INADDR_ANY) { 2427 #ifdef INET6 2428 /* 2429 * We use O_FORWARD_IP opcode for 2430 * fwd rule with tablearg, but tables 2431 * now support IPv6 addresses. And 2432 * when we are inspecting IPv6 packet, 2433 * we can use nh6 field from 2434 * table_value as next_hop6 address. 2435 */ 2436 if (is_ipv6) { 2437 struct sockaddr_in6 *sa6; 2438 2439 sa6 = args->next_hop6 = 2440 &args->hopstore6; 2441 sa6->sin6_family = AF_INET6; 2442 sa6->sin6_len = sizeof(*sa6); 2443 sa6->sin6_addr = TARG_VAL( 2444 chain, tablearg, nh6); 2445 /* 2446 * Set sin6_scope_id only for 2447 * link-local unicast addresses. 2448 */ 2449 if (IN6_IS_ADDR_LINKLOCAL( 2450 &sa6->sin6_addr)) 2451 sa6->sin6_scope_id = 2452 TARG_VAL(chain, 2453 tablearg, 2454 zoneid); 2455 } else 2456 #endif 2457 { 2458 sa = args->next_hop = 2459 &args->hopstore; 2460 sa->sin_family = AF_INET; 2461 sa->sin_len = sizeof(*sa); 2462 sa->sin_addr.s_addr = htonl( 2463 TARG_VAL(chain, tablearg, 2464 nh4)); 2465 } 2466 } else { 2467 args->next_hop = sa; 2468 } 2469 } 2470 retval = IP_FW_PASS; 2471 l = 0; /* exit inner loop */ 2472 done = 1; /* exit outer loop */ 2473 break; 2474 2475 #ifdef INET6 2476 case O_FORWARD_IP6: 2477 if (args->eh) /* not valid on layer2 pkts */ 2478 break; 2479 if (q == NULL || q->rule != f || 2480 dyn_dir == MATCH_FORWARD) { 2481 struct sockaddr_in6 *sin6; 2482 2483 sin6 = &(((ipfw_insn_sa6 *)cmd)->sa); 2484 args->next_hop6 = sin6; 2485 } 2486 retval = IP_FW_PASS; 2487 l = 0; /* exit inner loop */ 2488 done = 1; /* exit outer loop */ 2489 break; 2490 #endif 2491 2492 case O_NETGRAPH: 2493 case O_NGTEE: 2494 set_match(args, f_pos, chain); 2495 args->rule.info = TARG(cmd->arg1, netgraph); 2496 if (V_fw_one_pass) 2497 args->rule.info |= IPFW_ONEPASS; 2498 retval = (cmd->opcode == O_NETGRAPH) ? 2499 IP_FW_NETGRAPH : IP_FW_NGTEE; 2500 l = 0; /* exit inner loop */ 2501 done = 1; /* exit outer loop */ 2502 break; 2503 2504 case O_SETFIB: { 2505 uint32_t fib; 2506 2507 IPFW_INC_RULE_COUNTER(f, pktlen); 2508 fib = TARG(cmd->arg1, fib) & 0x7FFF; 2509 if (fib >= rt_numfibs) 2510 fib = 0; 2511 M_SETFIB(m, fib); 2512 args->f_id.fib = fib; 2513 l = 0; /* exit inner loop */ 2514 break; 2515 } 2516 2517 case O_SETDSCP: { 2518 uint16_t code; 2519 2520 code = TARG(cmd->arg1, dscp) & 0x3F; 2521 l = 0; /* exit inner loop */ 2522 if (is_ipv4) { 2523 uint16_t old; 2524 2525 old = *(uint16_t *)ip; 2526 ip->ip_tos = (code << 2) | 2527 (ip->ip_tos & 0x03); 2528 ip->ip_sum = cksum_adjust(ip->ip_sum, 2529 old, *(uint16_t *)ip); 2530 } else if (is_ipv6) { 2531 uint8_t *v; 2532 2533 v = &((struct ip6_hdr *)ip)->ip6_vfc; 2534 *v = (*v & 0xF0) | (code >> 2); 2535 v++; 2536 *v = (*v & 0x3F) | ((code & 0x03) << 6); 2537 } else 2538 break; 2539 2540 IPFW_INC_RULE_COUNTER(f, pktlen); 2541 break; 2542 } 2543 2544 case O_NAT: 2545 l = 0; /* exit inner loop */ 2546 done = 1; /* exit outer loop */ 2547 if (!IPFW_NAT_LOADED) { 2548 retval = IP_FW_DENY; 2549 break; 2550 } 2551 2552 struct cfg_nat *t; 2553 int nat_id; 2554 2555 set_match(args, f_pos, chain); 2556 /* Check if this is 'global' nat rule */ 2557 if (cmd->arg1 == IP_FW_NAT44_GLOBAL) { 2558 retval = ipfw_nat_ptr(args, NULL, m); 2559 break; 2560 } 2561 t = ((ipfw_insn_nat *)cmd)->nat; 2562 if (t == NULL) { 2563 nat_id = TARG(cmd->arg1, nat); 2564 t = (*lookup_nat_ptr)(&chain->nat, nat_id); 2565 2566 if (t == NULL) { 2567 retval = IP_FW_DENY; 2568 break; 2569 } 2570 if (cmd->arg1 != IP_FW_TARG) 2571 ((ipfw_insn_nat *)cmd)->nat = t; 2572 } 2573 retval = ipfw_nat_ptr(args, t, m); 2574 break; 2575 2576 case O_REASS: { 2577 int ip_off; 2578 2579 IPFW_INC_RULE_COUNTER(f, pktlen); 2580 l = 0; /* in any case exit inner loop */ 2581 ip_off = ntohs(ip->ip_off); 2582 2583 /* if not fragmented, go to next rule */ 2584 if ((ip_off & (IP_MF | IP_OFFMASK)) == 0) 2585 break; 2586 2587 args->m = m = ip_reass(m); 2588 2589 /* 2590 * do IP header checksum fixup. 2591 */ 2592 if (m == NULL) { /* fragment got swallowed */ 2593 retval = IP_FW_DENY; 2594 } else { /* good, packet complete */ 2595 int hlen; 2596 2597 ip = mtod(m, struct ip *); 2598 hlen = ip->ip_hl << 2; 2599 ip->ip_sum = 0; 2600 if (hlen == sizeof(struct ip)) 2601 ip->ip_sum = in_cksum_hdr(ip); 2602 else 2603 ip->ip_sum = in_cksum(m, hlen); 2604 retval = IP_FW_REASS; 2605 set_match(args, f_pos, chain); 2606 } 2607 done = 1; /* exit outer loop */ 2608 break; 2609 } 2610 case O_EXTERNAL_ACTION: 2611 l = 0; /* in any case exit inner loop */ 2612 retval = ipfw_run_eaction(chain, args, 2613 cmd, &done); 2614 /* 2615 * If both @retval and @done are zero, 2616 * consider this as rule matching and 2617 * update counters. 2618 */ 2619 if (retval == 0 && done == 0) { 2620 IPFW_INC_RULE_COUNTER(f, pktlen); 2621 /* 2622 * Reset the result of the last 2623 * dynamic state lookup. 2624 * External action can change 2625 * @args content, and it may be 2626 * used for new state lookup later. 2627 */ 2628 dyn_dir = MATCH_UNKNOWN; 2629 } 2630 break; 2631 2632 default: 2633 panic("-- unknown opcode %d\n", cmd->opcode); 2634 } /* end of switch() on opcodes */ 2635 /* 2636 * if we get here with l=0, then match is irrelevant. 2637 */ 2638 2639 if (cmd->len & F_NOT) 2640 match = !match; 2641 2642 if (match) { 2643 if (cmd->len & F_OR) 2644 skip_or = 1; 2645 } else { 2646 if (!(cmd->len & F_OR)) /* not an OR block, */ 2647 break; /* try next rule */ 2648 } 2649 2650 } /* end of inner loop, scan opcodes */ 2651 #undef PULLUP_LEN 2652 2653 if (done) 2654 break; 2655 2656 /* next_rule:; */ /* try next rule */ 2657 2658 } /* end of outer for, scan rules */ 2659 2660 if (done) { 2661 struct ip_fw *rule = chain->map[f_pos]; 2662 /* Update statistics */ 2663 IPFW_INC_RULE_COUNTER(rule, pktlen); 2664 } else { 2665 retval = IP_FW_DENY; 2666 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 2667 } 2668 IPFW_PF_RUNLOCK(chain); 2669 #ifdef __FreeBSD__ 2670 if (ucred_cache != NULL) 2671 crfree(ucred_cache); 2672 #endif 2673 return (retval); 2674 2675 pullup_failed: 2676 if (V_fw_verbose) 2677 printf("ipfw: pullup failed\n"); 2678 return (IP_FW_DENY); 2679 } 2680 2681 /* 2682 * Set maximum number of tables that can be used in given VNET ipfw instance. 2683 */ 2684 #ifdef SYSCTL_NODE 2685 static int 2686 sysctl_ipfw_table_num(SYSCTL_HANDLER_ARGS) 2687 { 2688 int error; 2689 unsigned int ntables; 2690 2691 ntables = V_fw_tables_max; 2692 2693 error = sysctl_handle_int(oidp, &ntables, 0, req); 2694 /* Read operation or some error */ 2695 if ((error != 0) || (req->newptr == NULL)) 2696 return (error); 2697 2698 return (ipfw_resize_tables(&V_layer3_chain, ntables)); 2699 } 2700 2701 /* 2702 * Switches table namespace between global and per-set. 2703 */ 2704 static int 2705 sysctl_ipfw_tables_sets(SYSCTL_HANDLER_ARGS) 2706 { 2707 int error; 2708 unsigned int sets; 2709 2710 sets = V_fw_tables_sets; 2711 2712 error = sysctl_handle_int(oidp, &sets, 0, req); 2713 /* Read operation or some error */ 2714 if ((error != 0) || (req->newptr == NULL)) 2715 return (error); 2716 2717 return (ipfw_switch_tables_namespace(&V_layer3_chain, sets)); 2718 } 2719 #endif 2720 2721 /* 2722 * Module and VNET glue 2723 */ 2724 2725 /* 2726 * Stuff that must be initialised only on boot or module load 2727 */ 2728 static int 2729 ipfw_init(void) 2730 { 2731 int error = 0; 2732 2733 /* 2734 * Only print out this stuff the first time around, 2735 * when called from the sysinit code. 2736 */ 2737 printf("ipfw2 " 2738 #ifdef INET6 2739 "(+ipv6) " 2740 #endif 2741 "initialized, divert %s, nat %s, " 2742 "default to %s, logging ", 2743 #ifdef IPDIVERT 2744 "enabled", 2745 #else 2746 "loadable", 2747 #endif 2748 #ifdef IPFIREWALL_NAT 2749 "enabled", 2750 #else 2751 "loadable", 2752 #endif 2753 default_to_accept ? "accept" : "deny"); 2754 2755 /* 2756 * Note: V_xxx variables can be accessed here but the vnet specific 2757 * initializer may not have been called yet for the VIMAGE case. 2758 * Tuneables will have been processed. We will print out values for 2759 * the default vnet. 2760 * XXX This should all be rationalized AFTER 8.0 2761 */ 2762 if (V_fw_verbose == 0) 2763 printf("disabled\n"); 2764 else if (V_verbose_limit == 0) 2765 printf("unlimited\n"); 2766 else 2767 printf("limited to %d packets/entry by default\n", 2768 V_verbose_limit); 2769 2770 /* Check user-supplied table count for validness */ 2771 if (default_fw_tables > IPFW_TABLES_MAX) 2772 default_fw_tables = IPFW_TABLES_MAX; 2773 2774 ipfw_init_sopt_handler(); 2775 ipfw_init_obj_rewriter(); 2776 ipfw_iface_init(); 2777 return (error); 2778 } 2779 2780 /* 2781 * Called for the removal of the last instance only on module unload. 2782 */ 2783 static void 2784 ipfw_destroy(void) 2785 { 2786 2787 ipfw_iface_destroy(); 2788 ipfw_destroy_sopt_handler(); 2789 ipfw_destroy_obj_rewriter(); 2790 printf("IP firewall unloaded\n"); 2791 } 2792 2793 /* 2794 * Stuff that must be initialized for every instance 2795 * (including the first of course). 2796 */ 2797 static int 2798 vnet_ipfw_init(const void *unused) 2799 { 2800 int error, first; 2801 struct ip_fw *rule = NULL; 2802 struct ip_fw_chain *chain; 2803 2804 chain = &V_layer3_chain; 2805 2806 first = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 2807 2808 /* First set up some values that are compile time options */ 2809 V_autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 2810 V_fw_deny_unknown_exthdrs = 1; 2811 #ifdef IPFIREWALL_VERBOSE 2812 V_fw_verbose = 1; 2813 #endif 2814 #ifdef IPFIREWALL_VERBOSE_LIMIT 2815 V_verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 2816 #endif 2817 #ifdef IPFIREWALL_NAT 2818 LIST_INIT(&chain->nat); 2819 #endif 2820 2821 /* Init shared services hash table */ 2822 ipfw_init_srv(chain); 2823 2824 ipfw_init_counters(); 2825 /* insert the default rule and create the initial map */ 2826 chain->n_rules = 1; 2827 chain->map = malloc(sizeof(struct ip_fw *), M_IPFW, M_WAITOK | M_ZERO); 2828 rule = ipfw_alloc_rule(chain, sizeof(struct ip_fw)); 2829 2830 /* Set initial number of tables */ 2831 V_fw_tables_max = default_fw_tables; 2832 error = ipfw_init_tables(chain, first); 2833 if (error) { 2834 printf("ipfw2: setting up tables failed\n"); 2835 free(chain->map, M_IPFW); 2836 free(rule, M_IPFW); 2837 return (ENOSPC); 2838 } 2839 2840 /* fill and insert the default rule */ 2841 rule->act_ofs = 0; 2842 rule->rulenum = IPFW_DEFAULT_RULE; 2843 rule->cmd_len = 1; 2844 rule->set = RESVD_SET; 2845 rule->cmd[0].len = 1; 2846 rule->cmd[0].opcode = default_to_accept ? O_ACCEPT : O_DENY; 2847 chain->default_rule = chain->map[0] = rule; 2848 chain->id = rule->id = 1; 2849 /* Pre-calculate rules length for legacy dump format */ 2850 chain->static_len = sizeof(struct ip_fw_rule0); 2851 2852 IPFW_LOCK_INIT(chain); 2853 ipfw_dyn_init(chain); 2854 ipfw_eaction_init(chain, first); 2855 #ifdef LINEAR_SKIPTO 2856 ipfw_init_skipto_cache(chain); 2857 #endif 2858 ipfw_bpf_init(first); 2859 2860 /* First set up some values that are compile time options */ 2861 V_ipfw_vnet_ready = 1; /* Open for business */ 2862 2863 /* 2864 * Hook the sockopt handler and pfil hooks for ipv4 and ipv6. 2865 * Even if the latter two fail we still keep the module alive 2866 * because the sockopt and layer2 paths are still useful. 2867 * ipfw[6]_hook return 0 on success, ENOENT on failure, 2868 * so we can ignore the exact return value and just set a flag. 2869 * 2870 * Note that V_fw[6]_enable are manipulated by a SYSCTL_PROC so 2871 * changes in the underlying (per-vnet) variables trigger 2872 * immediate hook()/unhook() calls. 2873 * In layer2 we have the same behaviour, except that V_ether_ipfw 2874 * is checked on each packet because there are no pfil hooks. 2875 */ 2876 V_ip_fw_ctl_ptr = ipfw_ctl3; 2877 error = ipfw_attach_hooks(1); 2878 return (error); 2879 } 2880 2881 /* 2882 * Called for the removal of each instance. 2883 */ 2884 static int 2885 vnet_ipfw_uninit(const void *unused) 2886 { 2887 struct ip_fw *reap; 2888 struct ip_fw_chain *chain = &V_layer3_chain; 2889 int i, last; 2890 2891 V_ipfw_vnet_ready = 0; /* tell new callers to go away */ 2892 /* 2893 * disconnect from ipv4, ipv6, layer2 and sockopt. 2894 * Then grab, release and grab again the WLOCK so we make 2895 * sure the update is propagated and nobody will be in. 2896 */ 2897 (void)ipfw_attach_hooks(0 /* detach */); 2898 V_ip_fw_ctl_ptr = NULL; 2899 2900 last = IS_DEFAULT_VNET(curvnet) ? 1 : 0; 2901 2902 IPFW_UH_WLOCK(chain); 2903 IPFW_UH_WUNLOCK(chain); 2904 2905 ipfw_dyn_uninit(0); /* run the callout_drain */ 2906 2907 IPFW_UH_WLOCK(chain); 2908 2909 reap = NULL; 2910 IPFW_WLOCK(chain); 2911 for (i = 0; i < chain->n_rules; i++) 2912 ipfw_reap_add(chain, &reap, chain->map[i]); 2913 free(chain->map, M_IPFW); 2914 #ifdef LINEAR_SKIPTO 2915 ipfw_destroy_skipto_cache(chain); 2916 #endif 2917 IPFW_WUNLOCK(chain); 2918 IPFW_UH_WUNLOCK(chain); 2919 ipfw_destroy_tables(chain, last); 2920 ipfw_eaction_uninit(chain, last); 2921 if (reap != NULL) 2922 ipfw_reap_rules(reap); 2923 vnet_ipfw_iface_destroy(chain); 2924 ipfw_destroy_srv(chain); 2925 IPFW_LOCK_DESTROY(chain); 2926 ipfw_dyn_uninit(1); /* free the remaining parts */ 2927 ipfw_destroy_counters(); 2928 ipfw_bpf_uninit(last); 2929 return (0); 2930 } 2931 2932 /* 2933 * Module event handler. 2934 * In general we have the choice of handling most of these events by the 2935 * event handler or by the (VNET_)SYS(UN)INIT handlers. I have chosen to 2936 * use the SYSINIT handlers as they are more capable of expressing the 2937 * flow of control during module and vnet operations, so this is just 2938 * a skeleton. Note there is no SYSINIT equivalent of the module 2939 * SHUTDOWN handler, but we don't have anything to do in that case anyhow. 2940 */ 2941 static int 2942 ipfw_modevent(module_t mod, int type, void *unused) 2943 { 2944 int err = 0; 2945 2946 switch (type) { 2947 case MOD_LOAD: 2948 /* Called once at module load or 2949 * system boot if compiled in. */ 2950 break; 2951 case MOD_QUIESCE: 2952 /* Called before unload. May veto unloading. */ 2953 break; 2954 case MOD_UNLOAD: 2955 /* Called during unload. */ 2956 break; 2957 case MOD_SHUTDOWN: 2958 /* Called during system shutdown. */ 2959 break; 2960 default: 2961 err = EOPNOTSUPP; 2962 break; 2963 } 2964 return err; 2965 } 2966 2967 static moduledata_t ipfwmod = { 2968 "ipfw", 2969 ipfw_modevent, 2970 0 2971 }; 2972 2973 /* Define startup order. */ 2974 #define IPFW_SI_SUB_FIREWALL SI_SUB_PROTO_FIREWALL 2975 #define IPFW_MODEVENT_ORDER (SI_ORDER_ANY - 255) /* On boot slot in here. */ 2976 #define IPFW_MODULE_ORDER (IPFW_MODEVENT_ORDER + 1) /* A little later. */ 2977 #define IPFW_VNET_ORDER (IPFW_MODEVENT_ORDER + 2) /* Later still. */ 2978 2979 DECLARE_MODULE(ipfw, ipfwmod, IPFW_SI_SUB_FIREWALL, IPFW_MODEVENT_ORDER); 2980 FEATURE(ipfw_ctl3, "ipfw new sockopt calls"); 2981 MODULE_VERSION(ipfw, 3); 2982 /* should declare some dependencies here */ 2983 2984 /* 2985 * Starting up. Done in order after ipfwmod() has been called. 2986 * VNET_SYSINIT is also called for each existing vnet and each new vnet. 2987 */ 2988 SYSINIT(ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 2989 ipfw_init, NULL); 2990 VNET_SYSINIT(vnet_ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 2991 vnet_ipfw_init, NULL); 2992 2993 /* 2994 * Closing up shop. These are done in REVERSE ORDER, but still 2995 * after ipfwmod() has been called. Not called on reboot. 2996 * VNET_SYSUNINIT is also called for each exiting vnet as it exits. 2997 * or when the module is unloaded. 2998 */ 2999 SYSUNINIT(ipfw_destroy, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 3000 ipfw_destroy, NULL); 3001 VNET_SYSUNINIT(vnet_ipfw_uninit, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 3002 vnet_ipfw_uninit, NULL); 3003 /* end of file */ 3004