Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/ip_fw2.c
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1 /*- 2 * Copyright (c) 2002 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 * $FreeBSD: releng/6.4/sys/netinet/ip_fw2.c 179148 2008-05-20 11:17:51Z dwmalone $ 26 */ 27 28 #define DEB(x) 29 #define DDB(x) x 30 31 /* 32 * Implement IP packet firewall (new version) 33 */ 34 35 #if !defined(KLD_MODULE) 36 #include "opt_ipfw.h" 37 #include "opt_ip6fw.h" 38 #include "opt_ipdivert.h" 39 #include "opt_ipdn.h" 40 #include "opt_inet.h" 41 #ifndef INET 42 #error IPFIREWALL requires INET. 43 #endif /* INET */ 44 #endif 45 #include "opt_inet6.h" 46 #include "opt_ipsec.h" 47 #include "opt_mac.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/condvar.h> 52 #include <sys/malloc.h> 53 #include <sys/mbuf.h> 54 #include <sys/kernel.h> 55 #include <sys/jail.h> 56 #include <sys/mac.h> 57 #include <sys/module.h> 58 #include <sys/proc.h> 59 #include <sys/socket.h> 60 #include <sys/socketvar.h> 61 #include <sys/sysctl.h> 62 #include <sys/syslog.h> 63 #include <sys/ucred.h> 64 #include <net/if.h> 65 #include <net/radix.h> 66 #include <net/route.h> 67 #include <netinet/in.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/in_var.h> 70 #include <netinet/in_pcb.h> 71 #include <netinet/ip.h> 72 #include <netinet/ip_var.h> 73 #include <netinet/ip_icmp.h> 74 #include <netinet/ip_fw.h> 75 #include <netinet/ip_divert.h> 76 #include <netinet/ip_dummynet.h> 77 #include <netinet/ip_carp.h> 78 #include <netinet/pim.h> 79 #include <netinet/tcp.h> 80 #include <netinet/tcp_timer.h> 81 #include <netinet/tcp_var.h> 82 #include <netinet/tcpip.h> 83 #include <netinet/udp.h> 84 #include <netinet/udp_var.h> 85 86 #include <netgraph/ng_ipfw.h> 87 88 #include <altq/if_altq.h> 89 90 #ifdef IPSEC 91 #include <netinet6/ipsec.h> 92 #endif 93 94 #include <netinet/ip6.h> 95 #include <netinet/icmp6.h> 96 #ifdef INET6 97 #include <netinet6/scope6_var.h> 98 #endif 99 100 #include <netinet/if_ether.h> /* XXX for ETHERTYPE_IP */ 101 102 #include <machine/in_cksum.h> /* XXX for in_cksum */ 103 104 /* 105 * set_disable contains one bit per set value (0..31). 106 * If the bit is set, all rules with the corresponding set 107 * are disabled. Set RESVD_SET(31) is reserved for the default rule 108 * and rules that are not deleted by the flush command, 109 * and CANNOT be disabled. 110 * Rules in set RESVD_SET can only be deleted explicitly. 111 */ 112 static u_int32_t set_disable; 113 114 static int fw_verbose; 115 static int verbose_limit; 116 117 static struct callout ipfw_timeout; 118 static uma_zone_t ipfw_dyn_rule_zone; 119 #define IPFW_DEFAULT_RULE 65535 120 121 /* 122 * Data structure to cache our ucred related 123 * information. This structure only gets used if 124 * the user specified UID/GID based constraints in 125 * a firewall rule. 126 */ 127 struct ip_fw_ugid { 128 gid_t fw_groups[NGROUPS]; 129 int fw_ngroups; 130 uid_t fw_uid; 131 int fw_prid; 132 }; 133 134 #define IPFW_TABLES_MAX 128 135 struct ip_fw_chain { 136 struct ip_fw *rules; /* list of rules */ 137 struct ip_fw *reap; /* list of rules to reap */ 138 struct radix_node_head *tables[IPFW_TABLES_MAX]; 139 struct mtx mtx; /* lock guarding rule list */ 140 int busy_count; /* busy count for rw locks */ 141 int want_write; 142 struct cv cv; 143 }; 144 #define IPFW_LOCK_INIT(_chain) \ 145 mtx_init(&(_chain)->mtx, "IPFW static rules", NULL, \ 146 MTX_DEF | MTX_RECURSE) 147 #define IPFW_LOCK_DESTROY(_chain) mtx_destroy(&(_chain)->mtx) 148 #define IPFW_WLOCK_ASSERT(_chain) do { \ 149 mtx_assert(&(_chain)->mtx, MA_OWNED); \ 150 NET_ASSERT_GIANT(); \ 151 } while (0) 152 153 static __inline void 154 IPFW_RLOCK(struct ip_fw_chain *chain) 155 { 156 mtx_lock(&chain->mtx); 157 chain->busy_count++; 158 mtx_unlock(&chain->mtx); 159 } 160 161 static __inline void 162 IPFW_RUNLOCK(struct ip_fw_chain *chain) 163 { 164 mtx_lock(&chain->mtx); 165 chain->busy_count--; 166 if (chain->busy_count == 0 && chain->want_write) 167 cv_signal(&chain->cv); 168 mtx_unlock(&chain->mtx); 169 } 170 171 static __inline void 172 IPFW_WLOCK(struct ip_fw_chain *chain) 173 { 174 mtx_lock(&chain->mtx); 175 chain->want_write++; 176 while (chain->busy_count > 0) 177 cv_wait(&chain->cv, &chain->mtx); 178 } 179 180 static __inline void 181 IPFW_WUNLOCK(struct ip_fw_chain *chain) 182 { 183 chain->want_write--; 184 cv_signal(&chain->cv); 185 mtx_unlock(&chain->mtx); 186 } 187 188 /* 189 * list of rules for layer 3 190 */ 191 static struct ip_fw_chain layer3_chain; 192 193 MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's"); 194 MALLOC_DEFINE(M_IPFW_TBL, "ipfw_tbl", "IpFw tables"); 195 196 struct table_entry { 197 struct radix_node rn[2]; 198 struct sockaddr_in addr, mask; 199 u_int32_t value; 200 }; 201 202 static int fw_debug = 1; 203 static int autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 204 205 #ifdef SYSCTL_NODE 206 SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 207 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, 208 CTLFLAG_RW | CTLFLAG_SECURE3, 209 &fw_enable, 0, "Enable ipfw"); 210 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, CTLFLAG_RW, 211 &autoinc_step, 0, "Rule number autincrement step"); 212 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 213 CTLFLAG_RW | CTLFLAG_SECURE3, 214 &fw_one_pass, 0, 215 "Only do a single pass through ipfw when using dummynet(4)"); 216 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW, 217 &fw_debug, 0, "Enable printing of debug ip_fw statements"); 218 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, 219 CTLFLAG_RW | CTLFLAG_SECURE3, 220 &fw_verbose, 0, "Log matches to ipfw rules"); 221 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, 222 &verbose_limit, 0, "Set upper limit of matches of ipfw rules logged"); 223 224 /* 225 * Description of dynamic rules. 226 * 227 * Dynamic rules are stored in lists accessed through a hash table 228 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 229 * be modified through the sysctl variable dyn_buckets which is 230 * updated when the table becomes empty. 231 * 232 * XXX currently there is only one list, ipfw_dyn. 233 * 234 * When a packet is received, its address fields are first masked 235 * with the mask defined for the rule, then hashed, then matched 236 * against the entries in the corresponding list. 237 * Dynamic rules can be used for different purposes: 238 * + stateful rules; 239 * + enforcing limits on the number of sessions; 240 * + in-kernel NAT (not implemented yet) 241 * 242 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 243 * measured in seconds and depending on the flags. 244 * 245 * The total number of dynamic rules is stored in dyn_count. 246 * The max number of dynamic rules is dyn_max. When we reach 247 * the maximum number of rules we do not create anymore. This is 248 * done to avoid consuming too much memory, but also too much 249 * time when searching on each packet (ideally, we should try instead 250 * to put a limit on the length of the list on each bucket...). 251 * 252 * Each dynamic rule holds a pointer to the parent ipfw rule so 253 * we know what action to perform. Dynamic rules are removed when 254 * the parent rule is deleted. XXX we should make them survive. 255 * 256 * There are some limitations with dynamic rules -- we do not 257 * obey the 'randomized match', and we do not do multiple 258 * passes through the firewall. XXX check the latter!!! 259 */ 260 static ipfw_dyn_rule **ipfw_dyn_v = NULL; 261 static u_int32_t dyn_buckets = 256; /* must be power of 2 */ 262 static u_int32_t curr_dyn_buckets = 256; /* must be power of 2 */ 263 264 static struct mtx ipfw_dyn_mtx; /* mutex guarding dynamic rules */ 265 #define IPFW_DYN_LOCK_INIT() \ 266 mtx_init(&ipfw_dyn_mtx, "IPFW dynamic rules", NULL, MTX_DEF) 267 #define IPFW_DYN_LOCK_DESTROY() mtx_destroy(&ipfw_dyn_mtx) 268 #define IPFW_DYN_LOCK() mtx_lock(&ipfw_dyn_mtx) 269 #define IPFW_DYN_UNLOCK() mtx_unlock(&ipfw_dyn_mtx) 270 #define IPFW_DYN_LOCK_ASSERT() mtx_assert(&ipfw_dyn_mtx, MA_OWNED) 271 272 /* 273 * Timeouts for various events in handing dynamic rules. 274 */ 275 static u_int32_t dyn_ack_lifetime = 300; 276 static u_int32_t dyn_syn_lifetime = 20; 277 static u_int32_t dyn_fin_lifetime = 1; 278 static u_int32_t dyn_rst_lifetime = 1; 279 static u_int32_t dyn_udp_lifetime = 10; 280 static u_int32_t dyn_short_lifetime = 5; 281 282 /* 283 * Keepalives are sent if dyn_keepalive is set. They are sent every 284 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 285 * seconds of lifetime of a rule. 286 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 287 * than dyn_keepalive_period. 288 */ 289 290 static u_int32_t dyn_keepalive_interval = 20; 291 static u_int32_t dyn_keepalive_period = 5; 292 static u_int32_t dyn_keepalive = 1; /* do send keepalives */ 293 294 static u_int32_t static_count; /* # of static rules */ 295 static u_int32_t static_len; /* size in bytes of static rules */ 296 static u_int32_t dyn_count; /* # of dynamic rules */ 297 static u_int32_t dyn_max = 4096; /* max # of dynamic rules */ 298 299 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW, 300 &dyn_buckets, 0, "Number of dyn. buckets"); 301 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD, 302 &curr_dyn_buckets, 0, "Current Number of dyn. buckets"); 303 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD, 304 &dyn_count, 0, "Number of dyn. rules"); 305 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW, 306 &dyn_max, 0, "Max number of dyn. rules"); 307 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD, 308 &static_count, 0, "Number of static rules"); 309 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW, 310 &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks"); 311 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW, 312 &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn"); 313 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW, 314 &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin"); 315 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW, 316 &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst"); 317 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW, 318 &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP"); 319 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW, 320 &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations"); 321 SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, CTLFLAG_RW, 322 &dyn_keepalive, 0, "Enable keepalives for dyn. rules"); 323 324 #ifdef INET6 325 /* 326 * IPv6 specific variables 327 */ 328 SYSCTL_DECL(_net_inet6_ip6); 329 330 static struct sysctl_ctx_list ip6_fw_sysctl_ctx; 331 static struct sysctl_oid *ip6_fw_sysctl_tree; 332 #endif /* INET6 */ 333 #endif /* SYSCTL_NODE */ 334 335 static int fw_deny_unknown_exthdrs = 1; 336 337 338 /* 339 * L3HDR maps an ipv4 pointer into a layer3 header pointer of type T 340 * Other macros just cast void * into the appropriate type 341 */ 342 #define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 343 #define TCP(p) ((struct tcphdr *)(p)) 344 #define UDP(p) ((struct udphdr *)(p)) 345 #define ICMP(p) ((struct icmphdr *)(p)) 346 #define ICMP6(p) ((struct icmp6_hdr *)(p)) 347 348 static __inline int 349 icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd) 350 { 351 int type = icmp->icmp_type; 352 353 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 354 } 355 356 #define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 357 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 358 359 static int 360 is_icmp_query(struct icmphdr *icmp) 361 { 362 int type = icmp->icmp_type; 363 364 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 365 } 366 #undef TT 367 368 /* 369 * The following checks use two arrays of 8 or 16 bits to store the 370 * bits that we want set or clear, respectively. They are in the 371 * low and high half of cmd->arg1 or cmd->d[0]. 372 * 373 * We scan options and store the bits we find set. We succeed if 374 * 375 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 376 * 377 * The code is sometimes optimized not to store additional variables. 378 */ 379 380 static int 381 flags_match(ipfw_insn *cmd, u_int8_t bits) 382 { 383 u_char want_clear; 384 bits = ~bits; 385 386 if ( ((cmd->arg1 & 0xff) & bits) != 0) 387 return 0; /* some bits we want set were clear */ 388 want_clear = (cmd->arg1 >> 8) & 0xff; 389 if ( (want_clear & bits) != want_clear) 390 return 0; /* some bits we want clear were set */ 391 return 1; 392 } 393 394 static int 395 ipopts_match(struct ip *ip, ipfw_insn *cmd) 396 { 397 int optlen, bits = 0; 398 u_char *cp = (u_char *)(ip + 1); 399 int x = (ip->ip_hl << 2) - sizeof (struct ip); 400 401 for (; x > 0; x -= optlen, cp += optlen) { 402 int opt = cp[IPOPT_OPTVAL]; 403 404 if (opt == IPOPT_EOL) 405 break; 406 if (opt == IPOPT_NOP) 407 optlen = 1; 408 else { 409 optlen = cp[IPOPT_OLEN]; 410 if (optlen <= 0 || optlen > x) 411 return 0; /* invalid or truncated */ 412 } 413 switch (opt) { 414 415 default: 416 break; 417 418 case IPOPT_LSRR: 419 bits |= IP_FW_IPOPT_LSRR; 420 break; 421 422 case IPOPT_SSRR: 423 bits |= IP_FW_IPOPT_SSRR; 424 break; 425 426 case IPOPT_RR: 427 bits |= IP_FW_IPOPT_RR; 428 break; 429 430 case IPOPT_TS: 431 bits |= IP_FW_IPOPT_TS; 432 break; 433 } 434 } 435 return (flags_match(cmd, bits)); 436 } 437 438 static int 439 tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd) 440 { 441 int optlen, bits = 0; 442 u_char *cp = (u_char *)(tcp + 1); 443 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 444 445 for (; x > 0; x -= optlen, cp += optlen) { 446 int opt = cp[0]; 447 if (opt == TCPOPT_EOL) 448 break; 449 if (opt == TCPOPT_NOP) 450 optlen = 1; 451 else { 452 optlen = cp[1]; 453 if (optlen <= 0) 454 break; 455 } 456 457 switch (opt) { 458 459 default: 460 break; 461 462 case TCPOPT_MAXSEG: 463 bits |= IP_FW_TCPOPT_MSS; 464 break; 465 466 case TCPOPT_WINDOW: 467 bits |= IP_FW_TCPOPT_WINDOW; 468 break; 469 470 case TCPOPT_SACK_PERMITTED: 471 case TCPOPT_SACK: 472 bits |= IP_FW_TCPOPT_SACK; 473 break; 474 475 case TCPOPT_TIMESTAMP: 476 bits |= IP_FW_TCPOPT_TS; 477 break; 478 479 } 480 } 481 return (flags_match(cmd, bits)); 482 } 483 484 static int 485 iface_match(struct ifnet *ifp, ipfw_insn_if *cmd) 486 { 487 if (ifp == NULL) /* no iface with this packet, match fails */ 488 return 0; 489 /* Check by name or by IP address */ 490 if (cmd->name[0] != '\0') { /* match by name */ 491 /* Check name */ 492 if (cmd->p.glob) { 493 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 494 return(1); 495 } else { 496 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 497 return(1); 498 } 499 } else { 500 struct ifaddr *ia; 501 502 /* XXX lock? */ 503 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 504 if (ia->ifa_addr == NULL) 505 continue; 506 if (ia->ifa_addr->sa_family != AF_INET) 507 continue; 508 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 509 (ia->ifa_addr))->sin_addr.s_addr) 510 return(1); /* match */ 511 } 512 } 513 return(0); /* no match, fail ... */ 514 } 515 516 /* 517 * The verify_path function checks if a route to the src exists and 518 * if it is reachable via ifp (when provided). 519 * 520 * The 'verrevpath' option checks that the interface that an IP packet 521 * arrives on is the same interface that traffic destined for the 522 * packet's source address would be routed out of. The 'versrcreach' 523 * option just checks that the source address is reachable via any route 524 * (except default) in the routing table. These two are a measure to block 525 * forged packets. This is also commonly known as "anti-spoofing" or Unicast 526 * Reverse Path Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 527 * is purposely reminiscent of the Cisco IOS command, 528 * 529 * ip verify unicast reverse-path 530 * ip verify unicast source reachable-via any 531 * 532 * which implements the same functionality. But note that syntax is 533 * misleading. The check may be performed on all IP packets whether unicast, 534 * multicast, or broadcast. 535 */ 536 static int 537 verify_path(struct in_addr src, struct ifnet *ifp) 538 { 539 struct route ro; 540 struct sockaddr_in *dst; 541 542 bzero(&ro, sizeof(ro)); 543 544 dst = (struct sockaddr_in *)&(ro.ro_dst); 545 dst->sin_family = AF_INET; 546 dst->sin_len = sizeof(*dst); 547 dst->sin_addr = src; 548 rtalloc_ign(&ro, RTF_CLONING); 549 550 if (ro.ro_rt == NULL) 551 return 0; 552 553 /* 554 * If ifp is provided, check for equality with rtentry. 555 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 556 * in order to pass packets injected back by if_simloop(): 557 * if useloopback == 1 routing entry (via lo0) for our own address 558 * may exist, so we need to handle routing assymetry. 559 */ 560 if (ifp != NULL && ro.ro_rt->rt_ifa->ifa_ifp != ifp) { 561 RTFREE(ro.ro_rt); 562 return 0; 563 } 564 565 /* if no ifp provided, check if rtentry is not default route */ 566 if (ifp == NULL && 567 satosin(rt_key(ro.ro_rt))->sin_addr.s_addr == INADDR_ANY) { 568 RTFREE(ro.ro_rt); 569 return 0; 570 } 571 572 /* or if this is a blackhole/reject route */ 573 if (ifp == NULL && ro.ro_rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 574 RTFREE(ro.ro_rt); 575 return 0; 576 } 577 578 /* found valid route */ 579 RTFREE(ro.ro_rt); 580 return 1; 581 } 582 583 #ifdef INET6 584 /* 585 * ipv6 specific rules here... 586 */ 587 static __inline int 588 icmp6type_match (int type, ipfw_insn_u32 *cmd) 589 { 590 return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) ); 591 } 592 593 static int 594 flow6id_match( int curr_flow, ipfw_insn_u32 *cmd ) 595 { 596 int i; 597 for (i=0; i <= cmd->o.arg1; ++i ) 598 if (curr_flow == cmd->d[i] ) 599 return 1; 600 return 0; 601 } 602 603 /* support for IP6_*_ME opcodes */ 604 static int 605 search_ip6_addr_net (struct in6_addr * ip6_addr) 606 { 607 struct ifnet *mdc; 608 struct ifaddr *mdc2; 609 struct in6_ifaddr *fdm; 610 struct in6_addr copia; 611 612 TAILQ_FOREACH(mdc, &ifnet, if_link) 613 TAILQ_FOREACH(mdc2, &mdc->if_addrlist, ifa_list) { 614 if (!mdc2->ifa_addr) 615 continue; 616 if (mdc2->ifa_addr->sa_family == AF_INET6) { 617 fdm = (struct in6_ifaddr *)mdc2; 618 copia = fdm->ia_addr.sin6_addr; 619 /* need for leaving scope_id in the sock_addr */ 620 in6_clearscope(&copia); 621 if (IN6_ARE_ADDR_EQUAL(ip6_addr, &copia)) 622 return 1; 623 } 624 } 625 return 0; 626 } 627 628 static int 629 verify_path6(struct in6_addr *src, struct ifnet *ifp) 630 { 631 struct route_in6 ro; 632 struct sockaddr_in6 *dst; 633 634 bzero(&ro, sizeof(ro)); 635 636 dst = (struct sockaddr_in6 * )&(ro.ro_dst); 637 dst->sin6_family = AF_INET6; 638 dst->sin6_len = sizeof(*dst); 639 dst->sin6_addr = *src; 640 rtalloc_ign((struct route *)&ro, RTF_CLONING); 641 642 if (ro.ro_rt == NULL) 643 return 0; 644 645 /* 646 * if ifp is provided, check for equality with rtentry 647 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 648 * to support the case of sending packets to an address of our own. 649 * (where the former interface is the first argument of if_simloop() 650 * (=ifp), the latter is lo0) 651 */ 652 if (ifp != NULL && ro.ro_rt->rt_ifa->ifa_ifp != ifp) { 653 RTFREE(ro.ro_rt); 654 return 0; 655 } 656 657 /* if no ifp provided, check if rtentry is not default route */ 658 if (ifp == NULL && 659 IN6_IS_ADDR_UNSPECIFIED(&satosin6(rt_key(ro.ro_rt))->sin6_addr)) { 660 RTFREE(ro.ro_rt); 661 return 0; 662 } 663 664 /* or if this is a blackhole/reject route */ 665 if (ifp == NULL && ro.ro_rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 666 RTFREE(ro.ro_rt); 667 return 0; 668 } 669 670 /* found valid route */ 671 RTFREE(ro.ro_rt); 672 return 1; 673 674 } 675 static __inline int 676 hash_packet6(struct ipfw_flow_id *id) 677 { 678 u_int32_t i; 679 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 680 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 681 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 682 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^ 683 (id->dst_port) ^ (id->src_port); 684 return i; 685 } 686 687 static int 688 is_icmp6_query(int icmp6_type) 689 { 690 if ((icmp6_type <= ICMP6_MAXTYPE) && 691 (icmp6_type == ICMP6_ECHO_REQUEST || 692 icmp6_type == ICMP6_MEMBERSHIP_QUERY || 693 icmp6_type == ICMP6_WRUREQUEST || 694 icmp6_type == ICMP6_FQDN_QUERY || 695 icmp6_type == ICMP6_NI_QUERY)) 696 return (1); 697 698 return (0); 699 } 700 701 static void 702 send_reject6(struct ip_fw_args *args, int code, u_short offset, u_int hlen, struct ip6_hdr *ip6) 703 { 704 struct mbuf *m; 705 706 m = args->m; 707 if (code == ICMP6_UNREACH_RST && offset == 0 && 708 args->f_id.proto == IPPROTO_TCP) { 709 struct tcphdr *tcp; 710 tcp_seq ack, seq; 711 int flags; 712 struct { 713 struct ip6_hdr ip6; 714 struct tcphdr th; 715 } ti; 716 tcp = (struct tcphdr *)((char *)ip6 + hlen); 717 718 if ((tcp->th_flags & TH_RST) != 0) { 719 m_freem(m); 720 args->m = NULL; 721 return; 722 } 723 724 ti.ip6 = *ip6; 725 ti.th = *tcp; 726 ti.th.th_seq = ntohl(ti.th.th_seq); 727 ti.th.th_ack = ntohl(ti.th.th_ack); 728 ti.ip6.ip6_nxt = IPPROTO_TCP; 729 730 if (ti.th.th_flags & TH_ACK) { 731 ack = 0; 732 seq = ti.th.th_ack; 733 flags = TH_RST; 734 } else { 735 ack = ti.th.th_seq; 736 if ((m->m_flags & M_PKTHDR) != 0) { 737 /* 738 * total new data to ACK is: 739 * total packet length, 740 * minus the header length, 741 * minus the tcp header length. 742 */ 743 ack += m->m_pkthdr.len - hlen 744 - (ti.th.th_off << 2); 745 } else if (ip6->ip6_plen) { 746 ack += ntohs(ip6->ip6_plen) + sizeof(*ip6) - 747 hlen - (ti.th.th_off << 2); 748 } else { 749 m_freem(m); 750 return; 751 } 752 if (tcp->th_flags & TH_SYN) 753 ack++; 754 seq = 0; 755 flags = TH_RST|TH_ACK; 756 } 757 bcopy(&ti, ip6, sizeof(ti)); 758 /* 759 * m is only used to recycle the mbuf 760 * The data in it is never read so we don't need 761 * to correct the offsets or anything 762 */ 763 tcp_respond(NULL, ip6, tcp, m, ack, seq, flags); 764 } else if (code != ICMP6_UNREACH_RST) { /* Send an ICMPv6 unreach. */ 765 #if 0 766 /* 767 * Unlike above, the mbufs need to line up with the ip6 hdr, 768 * as the contents are read. We need to m_adj() the 769 * needed amount. 770 * The mbuf will however be thrown away so we can adjust it. 771 * Remember we did an m_pullup on it already so we 772 * can make some assumptions about contiguousness. 773 */ 774 if (args->L3offset) 775 m_adj(m, args->L3offset); 776 #endif 777 icmp6_error(m, ICMP6_DST_UNREACH, code, 0); 778 } else 779 m_freem(m); 780 781 args->m = NULL; 782 } 783 784 #endif /* INET6 */ 785 786 static u_int64_t norule_counter; /* counter for ipfw_log(NULL...) */ 787 788 #define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0 789 #define SNP(buf) buf, sizeof(buf) 790 791 /* 792 * We enter here when we have a rule with O_LOG. 793 * XXX this function alone takes about 2Kbytes of code! 794 */ 795 static void 796 ipfw_log(struct ip_fw *f, u_int hlen, struct ip_fw_args *args, 797 struct mbuf *m, struct ifnet *oif, u_short offset, uint32_t tablearg, struct ip *ip) 798 { 799 struct ether_header *eh = args->eh; 800 char *action; 801 int limit_reached = 0; 802 char action2[40], proto[128], fragment[32]; 803 804 fragment[0] = '\0'; 805 proto[0] = '\0'; 806 807 if (f == NULL) { /* bogus pkt */ 808 if (verbose_limit != 0 && norule_counter >= verbose_limit) 809 return; 810 norule_counter++; 811 if (norule_counter == verbose_limit) 812 limit_reached = verbose_limit; 813 action = "Refuse"; 814 } else { /* O_LOG is the first action, find the real one */ 815 ipfw_insn *cmd = ACTION_PTR(f); 816 ipfw_insn_log *l = (ipfw_insn_log *)cmd; 817 818 if (l->max_log != 0 && l->log_left == 0) 819 return; 820 l->log_left--; 821 if (l->log_left == 0) 822 limit_reached = l->max_log; 823 cmd += F_LEN(cmd); /* point to first action */ 824 if (cmd->opcode == O_ALTQ) { 825 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 826 827 snprintf(SNPARGS(action2, 0), "Altq %d", 828 altq->qid); 829 cmd += F_LEN(cmd); 830 } 831 if (cmd->opcode == O_PROB) 832 cmd += F_LEN(cmd); 833 834 if (cmd->opcode == O_TAG) 835 cmd += F_LEN(cmd); 836 837 action = action2; 838 switch (cmd->opcode) { 839 case O_DENY: 840 action = "Deny"; 841 break; 842 843 case O_REJECT: 844 if (cmd->arg1==ICMP_REJECT_RST) 845 action = "Reset"; 846 else if (cmd->arg1==ICMP_UNREACH_HOST) 847 action = "Reject"; 848 else 849 snprintf(SNPARGS(action2, 0), "Unreach %d", 850 cmd->arg1); 851 break; 852 853 case O_UNREACH6: 854 if (cmd->arg1==ICMP6_UNREACH_RST) 855 action = "Reset"; 856 else 857 snprintf(SNPARGS(action2, 0), "Unreach %d", 858 cmd->arg1); 859 break; 860 861 case O_ACCEPT: 862 action = "Accept"; 863 break; 864 case O_COUNT: 865 action = "Count"; 866 break; 867 case O_DIVERT: 868 snprintf(SNPARGS(action2, 0), "Divert %d", 869 cmd->arg1); 870 break; 871 case O_TEE: 872 snprintf(SNPARGS(action2, 0), "Tee %d", 873 cmd->arg1); 874 break; 875 case O_SKIPTO: 876 snprintf(SNPARGS(action2, 0), "SkipTo %d", 877 cmd->arg1); 878 break; 879 case O_PIPE: 880 snprintf(SNPARGS(action2, 0), "Pipe %d", 881 cmd->arg1); 882 break; 883 case O_QUEUE: 884 snprintf(SNPARGS(action2, 0), "Queue %d", 885 cmd->arg1); 886 break; 887 case O_FORWARD_IP: { 888 ipfw_insn_sa *sa = (ipfw_insn_sa *)cmd; 889 int len; 890 struct in_addr dummyaddr; 891 if (sa->sa.sin_addr.s_addr == INADDR_ANY) 892 dummyaddr.s_addr = htonl(tablearg); 893 else 894 dummyaddr.s_addr = sa->sa.sin_addr.s_addr; 895 896 len = snprintf(SNPARGS(action2, 0), "Forward to %s", 897 inet_ntoa(dummyaddr)); 898 899 if (sa->sa.sin_port) 900 snprintf(SNPARGS(action2, len), ":%d", 901 sa->sa.sin_port); 902 } 903 break; 904 case O_NETGRAPH: 905 snprintf(SNPARGS(action2, 0), "Netgraph %d", 906 cmd->arg1); 907 break; 908 case O_NGTEE: 909 snprintf(SNPARGS(action2, 0), "Ngtee %d", 910 cmd->arg1); 911 break; 912 default: 913 action = "UNKNOWN"; 914 break; 915 } 916 } 917 918 if (hlen == 0) { /* non-ip */ 919 snprintf(SNPARGS(proto, 0), "MAC"); 920 921 } else { 922 int len; 923 char src[48], dst[48]; 924 struct icmphdr *icmp; 925 struct tcphdr *tcp; 926 struct udphdr *udp; 927 #ifdef INET6 928 struct ip6_hdr *ip6 = NULL; 929 struct icmp6_hdr *icmp6; 930 #endif 931 src[0] = '\0'; 932 dst[0] = '\0'; 933 #ifdef INET6 934 if (IS_IP6_FLOW_ID(&(args->f_id))) { 935 snprintf(src, sizeof(src), "[%s]", 936 ip6_sprintf(&args->f_id.src_ip6)); 937 snprintf(dst, sizeof(dst), "[%s]", 938 ip6_sprintf(&args->f_id.dst_ip6)); 939 940 ip6 = (struct ip6_hdr *)ip; 941 tcp = (struct tcphdr *)(((char *)ip) + hlen); 942 udp = (struct udphdr *)(((char *)ip) + hlen); 943 } else 944 #endif 945 { 946 tcp = L3HDR(struct tcphdr, ip); 947 udp = L3HDR(struct udphdr, ip); 948 949 inet_ntoa_r(ip->ip_src, src); 950 inet_ntoa_r(ip->ip_dst, dst); 951 } 952 953 switch (args->f_id.proto) { 954 case IPPROTO_TCP: 955 len = snprintf(SNPARGS(proto, 0), "TCP %s", src); 956 if (offset == 0) 957 snprintf(SNPARGS(proto, len), ":%d %s:%d", 958 ntohs(tcp->th_sport), 959 dst, 960 ntohs(tcp->th_dport)); 961 else 962 snprintf(SNPARGS(proto, len), " %s", dst); 963 break; 964 965 case IPPROTO_UDP: 966 len = snprintf(SNPARGS(proto, 0), "UDP %s", src); 967 if (offset == 0) 968 snprintf(SNPARGS(proto, len), ":%d %s:%d", 969 ntohs(udp->uh_sport), 970 dst, 971 ntohs(udp->uh_dport)); 972 else 973 snprintf(SNPARGS(proto, len), " %s", dst); 974 break; 975 976 case IPPROTO_ICMP: 977 icmp = L3HDR(struct icmphdr, ip); 978 if (offset == 0) 979 len = snprintf(SNPARGS(proto, 0), 980 "ICMP:%u.%u ", 981 icmp->icmp_type, icmp->icmp_code); 982 else 983 len = snprintf(SNPARGS(proto, 0), "ICMP "); 984 len += snprintf(SNPARGS(proto, len), "%s", src); 985 snprintf(SNPARGS(proto, len), " %s", dst); 986 break; 987 #ifdef INET6 988 case IPPROTO_ICMPV6: 989 icmp6 = (struct icmp6_hdr *)(((char *)ip) + hlen); 990 if (offset == 0) 991 len = snprintf(SNPARGS(proto, 0), 992 "ICMPv6:%u.%u ", 993 icmp6->icmp6_type, icmp6->icmp6_code); 994 else 995 len = snprintf(SNPARGS(proto, 0), "ICMPv6 "); 996 len += snprintf(SNPARGS(proto, len), "%s", src); 997 snprintf(SNPARGS(proto, len), " %s", dst); 998 break; 999 #endif 1000 default: 1001 len = snprintf(SNPARGS(proto, 0), "P:%d %s", 1002 args->f_id.proto, src); 1003 snprintf(SNPARGS(proto, len), " %s", dst); 1004 break; 1005 } 1006 1007 #ifdef INET6 1008 if (IS_IP6_FLOW_ID(&(args->f_id))) { 1009 if (offset & (IP6F_OFF_MASK | IP6F_MORE_FRAG)) 1010 snprintf(SNPARGS(fragment, 0), 1011 " (frag %08x:%d@%d%s)", 1012 args->f_id.frag_id6, 1013 ntohs(ip6->ip6_plen) - hlen, 1014 ntohs(offset & IP6F_OFF_MASK) << 3, 1015 (offset & IP6F_MORE_FRAG) ? "+" : ""); 1016 } else 1017 #endif 1018 { 1019 int ip_off, ip_len; 1020 if (eh != NULL) { /* layer 2 packets are as on the wire */ 1021 ip_off = ntohs(ip->ip_off); 1022 ip_len = ntohs(ip->ip_len); 1023 } else { 1024 ip_off = ip->ip_off; 1025 ip_len = ip->ip_len; 1026 } 1027 if (ip_off & (IP_MF | IP_OFFMASK)) 1028 snprintf(SNPARGS(fragment, 0), 1029 " (frag %d:%d@%d%s)", 1030 ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2), 1031 offset << 3, 1032 (ip_off & IP_MF) ? "+" : ""); 1033 } 1034 } 1035 if (oif || m->m_pkthdr.rcvif) 1036 log(LOG_SECURITY | LOG_INFO, 1037 "ipfw: %d %s %s %s via %s%s\n", 1038 f ? f->rulenum : -1, 1039 action, proto, oif ? "out" : "in", 1040 oif ? oif->if_xname : m->m_pkthdr.rcvif->if_xname, 1041 fragment); 1042 else 1043 log(LOG_SECURITY | LOG_INFO, 1044 "ipfw: %d %s %s [no if info]%s\n", 1045 f ? f->rulenum : -1, 1046 action, proto, fragment); 1047 if (limit_reached) 1048 log(LOG_SECURITY | LOG_NOTICE, 1049 "ipfw: limit %d reached on entry %d\n", 1050 limit_reached, f ? f->rulenum : -1); 1051 } 1052 1053 /* 1054 * IMPORTANT: the hash function for dynamic rules must be commutative 1055 * in source and destination (ip,port), because rules are bidirectional 1056 * and we want to find both in the same bucket. 1057 */ 1058 static __inline int 1059 hash_packet(struct ipfw_flow_id *id) 1060 { 1061 u_int32_t i; 1062 1063 #ifdef INET6 1064 if (IS_IP6_FLOW_ID(id)) 1065 i = hash_packet6(id); 1066 else 1067 #endif /* INET6 */ 1068 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 1069 i &= (curr_dyn_buckets - 1); 1070 return i; 1071 } 1072 1073 /** 1074 * unlink a dynamic rule from a chain. prev is a pointer to 1075 * the previous one, q is a pointer to the rule to delete, 1076 * head is a pointer to the head of the queue. 1077 * Modifies q and potentially also head. 1078 */ 1079 #define UNLINK_DYN_RULE(prev, head, q) { \ 1080 ipfw_dyn_rule *old_q = q; \ 1081 \ 1082 /* remove a refcount to the parent */ \ 1083 if (q->dyn_type == O_LIMIT) \ 1084 q->parent->count--; \ 1085 DEB(printf("ipfw: unlink entry 0x%08x %d -> 0x%08x %d, %d left\n",\ 1086 (q->id.src_ip), (q->id.src_port), \ 1087 (q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \ 1088 if (prev != NULL) \ 1089 prev->next = q = q->next; \ 1090 else \ 1091 head = q = q->next; \ 1092 dyn_count--; \ 1093 uma_zfree(ipfw_dyn_rule_zone, old_q); } 1094 1095 #define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 1096 1097 /** 1098 * Remove dynamic rules pointing to "rule", or all of them if rule == NULL. 1099 * 1100 * If keep_me == NULL, rules are deleted even if not expired, 1101 * otherwise only expired rules are removed. 1102 * 1103 * The value of the second parameter is also used to point to identify 1104 * a rule we absolutely do not want to remove (e.g. because we are 1105 * holding a reference to it -- this is the case with O_LIMIT_PARENT 1106 * rules). The pointer is only used for comparison, so any non-null 1107 * value will do. 1108 */ 1109 static void 1110 remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me) 1111 { 1112 static u_int32_t last_remove = 0; 1113 1114 #define FORCE (keep_me == NULL) 1115 1116 ipfw_dyn_rule *prev, *q; 1117 int i, pass = 0, max_pass = 0; 1118 1119 IPFW_DYN_LOCK_ASSERT(); 1120 1121 if (ipfw_dyn_v == NULL || dyn_count == 0) 1122 return; 1123 /* do not expire more than once per second, it is useless */ 1124 if (!FORCE && last_remove == time_uptime) 1125 return; 1126 last_remove = time_uptime; 1127 1128 /* 1129 * because O_LIMIT refer to parent rules, during the first pass only 1130 * remove child and mark any pending LIMIT_PARENT, and remove 1131 * them in a second pass. 1132 */ 1133 next_pass: 1134 for (i = 0 ; i < curr_dyn_buckets ; i++) { 1135 for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) { 1136 /* 1137 * Logic can become complex here, so we split tests. 1138 */ 1139 if (q == keep_me) 1140 goto next; 1141 if (rule != NULL && rule != q->rule) 1142 goto next; /* not the one we are looking for */ 1143 if (q->dyn_type == O_LIMIT_PARENT) { 1144 /* 1145 * handle parent in the second pass, 1146 * record we need one. 1147 */ 1148 max_pass = 1; 1149 if (pass == 0) 1150 goto next; 1151 if (FORCE && q->count != 0 ) { 1152 /* XXX should not happen! */ 1153 printf("ipfw: OUCH! cannot remove rule," 1154 " count %d\n", q->count); 1155 } 1156 } else { 1157 if (!FORCE && 1158 !TIME_LEQ( q->expire, time_uptime )) 1159 goto next; 1160 } 1161 if (q->dyn_type != O_LIMIT_PARENT || !q->count) { 1162 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 1163 continue; 1164 } 1165 next: 1166 prev=q; 1167 q=q->next; 1168 } 1169 } 1170 if (pass++ < max_pass) 1171 goto next_pass; 1172 } 1173 1174 1175 /** 1176 * lookup a dynamic rule. 1177 */ 1178 static ipfw_dyn_rule * 1179 lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int *match_direction, 1180 struct tcphdr *tcp) 1181 { 1182 /* 1183 * stateful ipfw extensions. 1184 * Lookup into dynamic session queue 1185 */ 1186 #define MATCH_REVERSE 0 1187 #define MATCH_FORWARD 1 1188 #define MATCH_NONE 2 1189 #define MATCH_UNKNOWN 3 1190 int i, dir = MATCH_NONE; 1191 ipfw_dyn_rule *prev, *q=NULL; 1192 1193 IPFW_DYN_LOCK_ASSERT(); 1194 1195 if (ipfw_dyn_v == NULL) 1196 goto done; /* not found */ 1197 i = hash_packet( pkt ); 1198 for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) { 1199 if (q->dyn_type == O_LIMIT_PARENT && q->count) 1200 goto next; 1201 if (TIME_LEQ( q->expire, time_uptime)) { /* expire entry */ 1202 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 1203 continue; 1204 } 1205 if (pkt->proto == q->id.proto && 1206 q->dyn_type != O_LIMIT_PARENT) { 1207 if (IS_IP6_FLOW_ID(pkt)) { 1208 if (IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 1209 &(q->id.src_ip6)) && 1210 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 1211 &(q->id.dst_ip6)) && 1212 pkt->src_port == q->id.src_port && 1213 pkt->dst_port == q->id.dst_port ) { 1214 dir = MATCH_FORWARD; 1215 break; 1216 } 1217 if (IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 1218 &(q->id.dst_ip6)) && 1219 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 1220 &(q->id.src_ip6)) && 1221 pkt->src_port == q->id.dst_port && 1222 pkt->dst_port == q->id.src_port ) { 1223 dir = MATCH_REVERSE; 1224 break; 1225 } 1226 } else { 1227 if (pkt->src_ip == q->id.src_ip && 1228 pkt->dst_ip == q->id.dst_ip && 1229 pkt->src_port == q->id.src_port && 1230 pkt->dst_port == q->id.dst_port ) { 1231 dir = MATCH_FORWARD; 1232 break; 1233 } 1234 if (pkt->src_ip == q->id.dst_ip && 1235 pkt->dst_ip == q->id.src_ip && 1236 pkt->src_port == q->id.dst_port && 1237 pkt->dst_port == q->id.src_port ) { 1238 dir = MATCH_REVERSE; 1239 break; 1240 } 1241 } 1242 } 1243 next: 1244 prev = q; 1245 q = q->next; 1246 } 1247 if (q == NULL) 1248 goto done; /* q = NULL, not found */ 1249 1250 if ( prev != NULL) { /* found and not in front */ 1251 prev->next = q->next; 1252 q->next = ipfw_dyn_v[i]; 1253 ipfw_dyn_v[i] = q; 1254 } 1255 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 1256 u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST); 1257 1258 #define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 1259 #define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 1260 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8); 1261 switch (q->state) { 1262 case TH_SYN: /* opening */ 1263 q->expire = time_uptime + dyn_syn_lifetime; 1264 break; 1265 1266 case BOTH_SYN: /* move to established */ 1267 case BOTH_SYN | TH_FIN : /* one side tries to close */ 1268 case BOTH_SYN | (TH_FIN << 8) : 1269 if (tcp) { 1270 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 1271 u_int32_t ack = ntohl(tcp->th_ack); 1272 if (dir == MATCH_FORWARD) { 1273 if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd)) 1274 q->ack_fwd = ack; 1275 else { /* ignore out-of-sequence */ 1276 break; 1277 } 1278 } else { 1279 if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev)) 1280 q->ack_rev = ack; 1281 else { /* ignore out-of-sequence */ 1282 break; 1283 } 1284 } 1285 } 1286 q->expire = time_uptime + dyn_ack_lifetime; 1287 break; 1288 1289 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 1290 if (dyn_fin_lifetime >= dyn_keepalive_period) 1291 dyn_fin_lifetime = dyn_keepalive_period - 1; 1292 q->expire = time_uptime + dyn_fin_lifetime; 1293 break; 1294 1295 default: 1296 #if 0 1297 /* 1298 * reset or some invalid combination, but can also 1299 * occur if we use keep-state the wrong way. 1300 */ 1301 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 1302 printf("invalid state: 0x%x\n", q->state); 1303 #endif 1304 if (dyn_rst_lifetime >= dyn_keepalive_period) 1305 dyn_rst_lifetime = dyn_keepalive_period - 1; 1306 q->expire = time_uptime + dyn_rst_lifetime; 1307 break; 1308 } 1309 } else if (pkt->proto == IPPROTO_UDP) { 1310 q->expire = time_uptime + dyn_udp_lifetime; 1311 } else { 1312 /* other protocols */ 1313 q->expire = time_uptime + dyn_short_lifetime; 1314 } 1315 done: 1316 if (match_direction) 1317 *match_direction = dir; 1318 return q; 1319 } 1320 1321 static ipfw_dyn_rule * 1322 lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 1323 struct tcphdr *tcp) 1324 { 1325 ipfw_dyn_rule *q; 1326 1327 IPFW_DYN_LOCK(); 1328 q = lookup_dyn_rule_locked(pkt, match_direction, tcp); 1329 if (q == NULL) 1330 IPFW_DYN_UNLOCK(); 1331 /* NB: return table locked when q is not NULL */ 1332 return q; 1333 } 1334 1335 static void 1336 realloc_dynamic_table(void) 1337 { 1338 IPFW_DYN_LOCK_ASSERT(); 1339 1340 /* 1341 * Try reallocation, make sure we have a power of 2 and do 1342 * not allow more than 64k entries. In case of overflow, 1343 * default to 1024. 1344 */ 1345 1346 if (dyn_buckets > 65536) 1347 dyn_buckets = 1024; 1348 if ((dyn_buckets & (dyn_buckets-1)) != 0) { /* not a power of 2 */ 1349 dyn_buckets = curr_dyn_buckets; /* reset */ 1350 return; 1351 } 1352 curr_dyn_buckets = dyn_buckets; 1353 if (ipfw_dyn_v != NULL) 1354 free(ipfw_dyn_v, M_IPFW); 1355 for (;;) { 1356 ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof(ipfw_dyn_rule *), 1357 M_IPFW, M_NOWAIT | M_ZERO); 1358 if (ipfw_dyn_v != NULL || curr_dyn_buckets <= 2) 1359 break; 1360 curr_dyn_buckets /= 2; 1361 } 1362 } 1363 1364 /** 1365 * Install state of type 'type' for a dynamic session. 1366 * The hash table contains two type of rules: 1367 * - regular rules (O_KEEP_STATE) 1368 * - rules for sessions with limited number of sess per user 1369 * (O_LIMIT). When they are created, the parent is 1370 * increased by 1, and decreased on delete. In this case, 1371 * the third parameter is the parent rule and not the chain. 1372 * - "parent" rules for the above (O_LIMIT_PARENT). 1373 */ 1374 static ipfw_dyn_rule * 1375 add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule) 1376 { 1377 ipfw_dyn_rule *r; 1378 int i; 1379 1380 IPFW_DYN_LOCK_ASSERT(); 1381 1382 if (ipfw_dyn_v == NULL || 1383 (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) { 1384 realloc_dynamic_table(); 1385 if (ipfw_dyn_v == NULL) 1386 return NULL; /* failed ! */ 1387 } 1388 i = hash_packet(id); 1389 1390 r = uma_zalloc(ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 1391 if (r == NULL) { 1392 printf ("ipfw: sorry cannot allocate state\n"); 1393 return NULL; 1394 } 1395 1396 /* increase refcount on parent, and set pointer */ 1397 if (dyn_type == O_LIMIT) { 1398 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 1399 if ( parent->dyn_type != O_LIMIT_PARENT) 1400 panic("invalid parent"); 1401 parent->count++; 1402 r->parent = parent; 1403 rule = parent->rule; 1404 } 1405 1406 r->id = *id; 1407 r->expire = time_uptime + dyn_syn_lifetime; 1408 r->rule = rule; 1409 r->dyn_type = dyn_type; 1410 r->pcnt = r->bcnt = 0; 1411 r->count = 0; 1412 1413 r->bucket = i; 1414 r->next = ipfw_dyn_v[i]; 1415 ipfw_dyn_v[i] = r; 1416 dyn_count++; 1417 DEB(printf("ipfw: add dyn entry ty %d 0x%08x %d -> 0x%08x %d, total %d\n", 1418 dyn_type, 1419 (r->id.src_ip), (r->id.src_port), 1420 (r->id.dst_ip), (r->id.dst_port), 1421 dyn_count ); ) 1422 return r; 1423 } 1424 1425 /** 1426 * lookup dynamic parent rule using pkt and rule as search keys. 1427 * If the lookup fails, then install one. 1428 */ 1429 static ipfw_dyn_rule * 1430 lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule) 1431 { 1432 ipfw_dyn_rule *q; 1433 int i; 1434 1435 IPFW_DYN_LOCK_ASSERT(); 1436 1437 if (ipfw_dyn_v) { 1438 int is_v6 = IS_IP6_FLOW_ID(pkt); 1439 i = hash_packet( pkt ); 1440 for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next) 1441 if (q->dyn_type == O_LIMIT_PARENT && 1442 rule== q->rule && 1443 pkt->proto == q->id.proto && 1444 pkt->src_port == q->id.src_port && 1445 pkt->dst_port == q->id.dst_port && 1446 ( 1447 (is_v6 && 1448 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 1449 &(q->id.src_ip6)) && 1450 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 1451 &(q->id.dst_ip6))) || 1452 (!is_v6 && 1453 pkt->src_ip == q->id.src_ip && 1454 pkt->dst_ip == q->id.dst_ip) 1455 ) 1456 ) { 1457 q->expire = time_uptime + dyn_short_lifetime; 1458 DEB(printf("ipfw: lookup_dyn_parent found 0x%p\n",q);) 1459 return q; 1460 } 1461 } 1462 return add_dyn_rule(pkt, O_LIMIT_PARENT, rule); 1463 } 1464 1465 /** 1466 * Install dynamic state for rule type cmd->o.opcode 1467 * 1468 * Returns 1 (failure) if state is not installed because of errors or because 1469 * session limitations are enforced. 1470 */ 1471 static int 1472 install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 1473 struct ip_fw_args *args, uint32_t tablearg) 1474 { 1475 static int last_log; 1476 ipfw_dyn_rule *q; 1477 struct in_addr da; 1478 char src[48], dst[48]; 1479 1480 src[0] = '\0'; 1481 dst[0] = '\0'; 1482 1483 DEB( 1484 printf("ipfw: %s: type %d 0x%08x %u -> 0x%08x %u\n", 1485 __func__, cmd->o.opcode, 1486 (args->f_id.src_ip), (args->f_id.src_port), 1487 (args->f_id.dst_ip), (args->f_id.dst_port)); 1488 ) 1489 1490 IPFW_DYN_LOCK(); 1491 1492 q = lookup_dyn_rule_locked(&args->f_id, NULL, NULL); 1493 1494 if (q != NULL) { /* should never occur */ 1495 if (last_log != time_uptime) { 1496 last_log = time_uptime; 1497 printf("ipfw: %s: entry already present, done\n", 1498 __func__); 1499 } 1500 IPFW_DYN_UNLOCK(); 1501 return (0); 1502 } 1503 1504 if (dyn_count >= dyn_max) 1505 /* Run out of slots, try to remove any expired rule. */ 1506 remove_dyn_rule(NULL, (ipfw_dyn_rule *)1); 1507 1508 if (dyn_count >= dyn_max) { 1509 if (last_log != time_uptime) { 1510 last_log = time_uptime; 1511 printf("ipfw: %s: Too many dynamic rules\n", __func__); 1512 } 1513 IPFW_DYN_UNLOCK(); 1514 return (1); /* cannot install, notify caller */ 1515 } 1516 1517 switch (cmd->o.opcode) { 1518 case O_KEEP_STATE: /* bidir rule */ 1519 add_dyn_rule(&args->f_id, O_KEEP_STATE, rule); 1520 break; 1521 1522 case O_LIMIT: { /* limit number of sessions */ 1523 struct ipfw_flow_id id; 1524 ipfw_dyn_rule *parent; 1525 uint32_t conn_limit; 1526 uint16_t limit_mask = cmd->limit_mask; 1527 1528 conn_limit = (cmd->conn_limit == IP_FW_TABLEARG) ? 1529 tablearg : cmd->conn_limit; 1530 1531 DEB( 1532 if (cmd->conn_limit == IP_FW_TABLEARG) 1533 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 1534 "(tablearg)\n", __func__, conn_limit); 1535 else 1536 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 1537 __func__, conn_limit); 1538 ) 1539 1540 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 1541 id.proto = args->f_id.proto; 1542 id.addr_type = args->f_id.addr_type; 1543 1544 if (IS_IP6_FLOW_ID (&(args->f_id))) { 1545 if (limit_mask & DYN_SRC_ADDR) 1546 id.src_ip6 = args->f_id.src_ip6; 1547 if (limit_mask & DYN_DST_ADDR) 1548 id.dst_ip6 = args->f_id.dst_ip6; 1549 } else { 1550 if (limit_mask & DYN_SRC_ADDR) 1551 id.src_ip = args->f_id.src_ip; 1552 if (limit_mask & DYN_DST_ADDR) 1553 id.dst_ip = args->f_id.dst_ip; 1554 } 1555 if (limit_mask & DYN_SRC_PORT) 1556 id.src_port = args->f_id.src_port; 1557 if (limit_mask & DYN_DST_PORT) 1558 id.dst_port = args->f_id.dst_port; 1559 if ((parent = lookup_dyn_parent(&id, rule)) == NULL) { 1560 printf("ipfw: %s: add parent failed\n", __func__); 1561 IPFW_DYN_UNLOCK(); 1562 return (1); 1563 } 1564 1565 if (parent->count >= conn_limit) { 1566 /* See if we can remove some expired rule. */ 1567 remove_dyn_rule(rule, parent); 1568 if (parent->count >= conn_limit) { 1569 if (fw_verbose && last_log != time_uptime) { 1570 last_log = time_uptime; 1571 #ifdef INET6 1572 /* 1573 * XXX IPv6 flows are not 1574 * supported yet. 1575 * */ 1576 if (IS_IP6_FLOW_ID(&(args->f_id))) { 1577 snprintf(src, sizeof(src), 1578 "[%s]", ip6_sprintf( 1579 &args->f_id.src_ip6)); 1580 snprintf(dst, sizeof(dst), 1581 "[%s]", ip6_sprintf( 1582 &args->f_id.dst_ip6)); 1583 } else 1584 #endif 1585 { 1586 da.s_addr = 1587 htonl(args->f_id.src_ip); 1588 inet_ntoa_r(da, src); 1589 da.s_addr = 1590 htonl(args->f_id.dst_ip); 1591 inet_ntoa_r(da, dst); 1592 } 1593 log(LOG_SECURITY | LOG_DEBUG, 1594 "%s %s:%u -> %s:%u, %s\n", 1595 "drop session", 1596 src, (args->f_id.src_port), 1597 dst, (args->f_id.dst_port), 1598 "too many entries"); 1599 } 1600 IPFW_DYN_UNLOCK(); 1601 return (1); 1602 } 1603 } 1604 add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent); 1605 break; 1606 } 1607 default: 1608 printf("ipfw: %s: unknown dynamic rule type %u\n", 1609 __func__, cmd->o.opcode); 1610 IPFW_DYN_UNLOCK(); 1611 return (1); 1612 } 1613 1614 /* XXX just set lifetime */ 1615 lookup_dyn_rule_locked(&args->f_id, NULL, NULL); 1616 1617 IPFW_DYN_UNLOCK(); 1618 return (0); 1619 } 1620 1621 /* 1622 * Generate a TCP packet, containing either a RST or a keepalive. 1623 * When flags & TH_RST, we are sending a RST packet, because of a 1624 * "reset" action matched the packet. 1625 * Otherwise we are sending a keepalive, and flags & TH_ 1626 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 1627 * so that MAC can label the reply appropriately. 1628 */ 1629 static struct mbuf * 1630 send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 1631 u_int32_t ack, int flags) 1632 { 1633 struct mbuf *m; 1634 struct ip *ip; 1635 struct tcphdr *tcp; 1636 1637 MGETHDR(m, M_DONTWAIT, MT_HEADER); 1638 if (m == 0) 1639 return (NULL); 1640 m->m_pkthdr.rcvif = (struct ifnet *)0; 1641 1642 #ifdef MAC 1643 if (replyto != NULL) 1644 mac_create_mbuf_netlayer(replyto, m); 1645 else 1646 mac_create_mbuf_from_firewall(m); 1647 #else 1648 (void)replyto; /* don't warn about unused arg */ 1649 #endif 1650 1651 m->m_pkthdr.len = m->m_len = sizeof(struct ip) + sizeof(struct tcphdr); 1652 m->m_data += max_linkhdr; 1653 1654 ip = mtod(m, struct ip *); 1655 bzero(ip, m->m_len); 1656 tcp = (struct tcphdr *)(ip + 1); /* no IP options */ 1657 ip->ip_p = IPPROTO_TCP; 1658 tcp->th_off = 5; 1659 /* 1660 * Assume we are sending a RST (or a keepalive in the reverse 1661 * direction), swap src and destination addresses and ports. 1662 */ 1663 ip->ip_src.s_addr = htonl(id->dst_ip); 1664 ip->ip_dst.s_addr = htonl(id->src_ip); 1665 tcp->th_sport = htons(id->dst_port); 1666 tcp->th_dport = htons(id->src_port); 1667 if (flags & TH_RST) { /* we are sending a RST */ 1668 if (flags & TH_ACK) { 1669 tcp->th_seq = htonl(ack); 1670 tcp->th_ack = htonl(0); 1671 tcp->th_flags = TH_RST; 1672 } else { 1673 if (flags & TH_SYN) 1674 seq++; 1675 tcp->th_seq = htonl(0); 1676 tcp->th_ack = htonl(seq); 1677 tcp->th_flags = TH_RST | TH_ACK; 1678 } 1679 } else { 1680 /* 1681 * We are sending a keepalive. flags & TH_SYN determines 1682 * the direction, forward if set, reverse if clear. 1683 * NOTE: seq and ack are always assumed to be correct 1684 * as set by the caller. This may be confusing... 1685 */ 1686 if (flags & TH_SYN) { 1687 /* 1688 * we have to rewrite the correct addresses! 1689 */ 1690 ip->ip_dst.s_addr = htonl(id->dst_ip); 1691 ip->ip_src.s_addr = htonl(id->src_ip); 1692 tcp->th_dport = htons(id->dst_port); 1693 tcp->th_sport = htons(id->src_port); 1694 } 1695 tcp->th_seq = htonl(seq); 1696 tcp->th_ack = htonl(ack); 1697 tcp->th_flags = TH_ACK; 1698 } 1699 /* 1700 * set ip_len to the payload size so we can compute 1701 * the tcp checksum on the pseudoheader 1702 * XXX check this, could save a couple of words ? 1703 */ 1704 ip->ip_len = htons(sizeof(struct tcphdr)); 1705 tcp->th_sum = in_cksum(m, m->m_pkthdr.len); 1706 /* 1707 * now fill fields left out earlier 1708 */ 1709 ip->ip_ttl = ip_defttl; 1710 ip->ip_len = m->m_pkthdr.len; 1711 m->m_flags |= M_SKIP_FIREWALL; 1712 return (m); 1713 } 1714 1715 /* 1716 * sends a reject message, consuming the mbuf passed as an argument. 1717 */ 1718 static void 1719 send_reject(struct ip_fw_args *args, int code, u_short offset, int ip_len, struct ip *ip) 1720 { 1721 1722 #if 0 1723 /* XXX When ip is not guaranteed to be at mtod() we will 1724 * need to account for this */ 1725 * The mbuf will however be thrown away so we can adjust it. 1726 * Remember we did an m_pullup on it already so we 1727 * can make some assumptions about contiguousness. 1728 */ 1729 if (args->L3offset) 1730 m_adj(m, args->L3offset); 1731 #endif 1732 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */ 1733 /* We need the IP header in host order for icmp_error(). */ 1734 if (args->eh != NULL) { 1735 ip->ip_len = ntohs(ip->ip_len); 1736 ip->ip_off = ntohs(ip->ip_off); 1737 } 1738 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 1739 } else if (offset == 0 && args->f_id.proto == IPPROTO_TCP) { 1740 struct tcphdr *const tcp = 1741 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 1742 if ( (tcp->th_flags & TH_RST) == 0) { 1743 struct mbuf *m; 1744 m = send_pkt(args->m, &(args->f_id), 1745 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 1746 tcp->th_flags | TH_RST); 1747 if (m != NULL) 1748 ip_output(m, NULL, NULL, 0, NULL, NULL); 1749 } 1750 m_freem(args->m); 1751 } else 1752 m_freem(args->m); 1753 args->m = NULL; 1754 } 1755 1756 /** 1757 * 1758 * Given an ip_fw *, lookup_next_rule will return a pointer 1759 * to the next rule, which can be either the jump 1760 * target (for skipto instructions) or the next one in the list (in 1761 * all other cases including a missing jump target). 1762 * The result is also written in the "next_rule" field of the rule. 1763 * Backward jumps are not allowed, so start looking from the next 1764 * rule... 1765 * 1766 * This never returns NULL -- in case we do not have an exact match, 1767 * the next rule is returned. When the ruleset is changed, 1768 * pointers are flushed so we are always correct. 1769 */ 1770 1771 static struct ip_fw * 1772 lookup_next_rule(struct ip_fw *me) 1773 { 1774 struct ip_fw *rule = NULL; 1775 ipfw_insn *cmd; 1776 1777 /* look for action, in case it is a skipto */ 1778 cmd = ACTION_PTR(me); 1779 if (cmd->opcode == O_LOG) 1780 cmd += F_LEN(cmd); 1781 if (cmd->opcode == O_ALTQ) 1782 cmd += F_LEN(cmd); 1783 if (cmd->opcode == O_TAG) 1784 cmd += F_LEN(cmd); 1785 if ( cmd->opcode == O_SKIPTO ) 1786 for (rule = me->next; rule ; rule = rule->next) 1787 if (rule->rulenum >= cmd->arg1) 1788 break; 1789 if (rule == NULL) /* failure or not a skipto */ 1790 rule = me->next; 1791 me->next_rule = rule; 1792 return rule; 1793 } 1794 1795 static int 1796 add_table_entry(struct ip_fw_chain *ch, uint16_t tbl, in_addr_t addr, 1797 uint8_t mlen, uint32_t value) 1798 { 1799 struct radix_node_head *rnh; 1800 struct table_entry *ent; 1801 1802 if (tbl >= IPFW_TABLES_MAX) 1803 return (EINVAL); 1804 rnh = ch->tables[tbl]; 1805 ent = malloc(sizeof(*ent), M_IPFW_TBL, M_NOWAIT | M_ZERO); 1806 if (ent == NULL) 1807 return (ENOMEM); 1808 ent->value = value; 1809 ent->addr.sin_len = ent->mask.sin_len = 8; 1810 ent->mask.sin_addr.s_addr = htonl(mlen ? ~((1 << (32 - mlen)) - 1) : 0); 1811 ent->addr.sin_addr.s_addr = addr & ent->mask.sin_addr.s_addr; 1812 IPFW_WLOCK(&layer3_chain); 1813 if (rnh->rnh_addaddr(&ent->addr, &ent->mask, rnh, (void *)ent) == 1814 NULL) { 1815 IPFW_WUNLOCK(&layer3_chain); 1816 free(ent, M_IPFW_TBL); 1817 return (EEXIST); 1818 } 1819 IPFW_WUNLOCK(&layer3_chain); 1820 return (0); 1821 } 1822 1823 static int 1824 del_table_entry(struct ip_fw_chain *ch, uint16_t tbl, in_addr_t addr, 1825 uint8_t mlen) 1826 { 1827 struct radix_node_head *rnh; 1828 struct table_entry *ent; 1829 struct sockaddr_in sa, mask; 1830 1831 if (tbl >= IPFW_TABLES_MAX) 1832 return (EINVAL); 1833 rnh = ch->tables[tbl]; 1834 sa.sin_len = mask.sin_len = 8; 1835 mask.sin_addr.s_addr = htonl(mlen ? ~((1 << (32 - mlen)) - 1) : 0); 1836 sa.sin_addr.s_addr = addr & mask.sin_addr.s_addr; 1837 IPFW_WLOCK(ch); 1838 ent = (struct table_entry *)rnh->rnh_deladdr(&sa, &mask, rnh); 1839 if (ent == NULL) { 1840 IPFW_WUNLOCK(ch); 1841 return (ESRCH); 1842 } 1843 IPFW_WUNLOCK(ch); 1844 free(ent, M_IPFW_TBL); 1845 return (0); 1846 } 1847 1848 static int 1849 flush_table_entry(struct radix_node *rn, void *arg) 1850 { 1851 struct radix_node_head * const rnh = arg; 1852 struct table_entry *ent; 1853 1854 ent = (struct table_entry *) 1855 rnh->rnh_deladdr(rn->rn_key, rn->rn_mask, rnh); 1856 if (ent != NULL) 1857 free(ent, M_IPFW_TBL); 1858 return (0); 1859 } 1860 1861 static int 1862 flush_table(struct ip_fw_chain *ch, uint16_t tbl) 1863 { 1864 struct radix_node_head *rnh; 1865 1866 IPFW_WLOCK_ASSERT(ch); 1867 1868 if (tbl >= IPFW_TABLES_MAX) 1869 return (EINVAL); 1870 rnh = ch->tables[tbl]; 1871 KASSERT(rnh != NULL, ("NULL IPFW table")); 1872 rnh->rnh_walktree(rnh, flush_table_entry, rnh); 1873 return (0); 1874 } 1875 1876 static void 1877 flush_tables(struct ip_fw_chain *ch) 1878 { 1879 uint16_t tbl; 1880 1881 IPFW_WLOCK_ASSERT(ch); 1882 1883 for (tbl = 0; tbl < IPFW_TABLES_MAX; tbl++) 1884 flush_table(ch, tbl); 1885 } 1886 1887 static int 1888 init_tables(struct ip_fw_chain *ch) 1889 { 1890 int i; 1891 uint16_t j; 1892 1893 for (i = 0; i < IPFW_TABLES_MAX; i++) { 1894 if (!rn_inithead((void **)&ch->tables[i], 32)) { 1895 for (j = 0; j < i; j++) { 1896 (void) flush_table(ch, j); 1897 } 1898 return (ENOMEM); 1899 } 1900 } 1901 return (0); 1902 } 1903 1904 static int 1905 lookup_table(struct ip_fw_chain *ch, uint16_t tbl, in_addr_t addr, 1906 uint32_t *val) 1907 { 1908 struct radix_node_head *rnh; 1909 struct table_entry *ent; 1910 struct sockaddr_in sa; 1911 1912 if (tbl >= IPFW_TABLES_MAX) 1913 return (0); 1914 rnh = ch->tables[tbl]; 1915 sa.sin_len = 8; 1916 sa.sin_addr.s_addr = addr; 1917 ent = (struct table_entry *)(rnh->rnh_lookup(&sa, NULL, rnh)); 1918 if (ent != NULL) { 1919 *val = ent->value; 1920 return (1); 1921 } 1922 return (0); 1923 } 1924 1925 static int 1926 count_table_entry(struct radix_node *rn, void *arg) 1927 { 1928 u_int32_t * const cnt = arg; 1929 1930 (*cnt)++; 1931 return (0); 1932 } 1933 1934 static int 1935 count_table(struct ip_fw_chain *ch, uint32_t tbl, uint32_t *cnt) 1936 { 1937 struct radix_node_head *rnh; 1938 1939 if (tbl >= IPFW_TABLES_MAX) 1940 return (EINVAL); 1941 rnh = ch->tables[tbl]; 1942 *cnt = 0; 1943 rnh->rnh_walktree(rnh, count_table_entry, cnt); 1944 return (0); 1945 } 1946 1947 static int 1948 dump_table_entry(struct radix_node *rn, void *arg) 1949 { 1950 struct table_entry * const n = (struct table_entry *)rn; 1951 ipfw_table * const tbl = arg; 1952 ipfw_table_entry *ent; 1953 1954 if (tbl->cnt == tbl->size) 1955 return (1); 1956 ent = &tbl->ent[tbl->cnt]; 1957 ent->tbl = tbl->tbl; 1958 if (in_nullhost(n->mask.sin_addr)) 1959 ent->masklen = 0; 1960 else 1961 ent->masklen = 33 - ffs(ntohl(n->mask.sin_addr.s_addr)); 1962 ent->addr = n->addr.sin_addr.s_addr; 1963 ent->value = n->value; 1964 tbl->cnt++; 1965 return (0); 1966 } 1967 1968 static int 1969 dump_table(struct ip_fw_chain *ch, ipfw_table *tbl) 1970 { 1971 struct radix_node_head *rnh; 1972 1973 if (tbl->tbl >= IPFW_TABLES_MAX) 1974 return (EINVAL); 1975 rnh = ch->tables[tbl->tbl]; 1976 tbl->cnt = 0; 1977 rnh->rnh_walktree(rnh, dump_table_entry, tbl); 1978 return (0); 1979 } 1980 1981 static void 1982 fill_ugid_cache(struct inpcb *inp, struct ip_fw_ugid *ugp) 1983 { 1984 struct ucred *cr; 1985 1986 if (inp->inp_socket != NULL) { 1987 cr = inp->inp_socket->so_cred; 1988 ugp->fw_prid = jailed(cr) ? 1989 cr->cr_prison->pr_id : -1; 1990 ugp->fw_uid = cr->cr_uid; 1991 ugp->fw_ngroups = cr->cr_ngroups; 1992 bcopy(cr->cr_groups, ugp->fw_groups, 1993 sizeof(ugp->fw_groups)); 1994 } 1995 } 1996 1997 static int 1998 check_uidgid(ipfw_insn_u32 *insn, 1999 int proto, struct ifnet *oif, 2000 struct in_addr dst_ip, u_int16_t dst_port, 2001 struct in_addr src_ip, u_int16_t src_port, 2002 struct ip_fw_ugid *ugp, int *lookup, struct inpcb *inp) 2003 { 2004 struct inpcbinfo *pi; 2005 int wildcard; 2006 struct inpcb *pcb; 2007 int match; 2008 gid_t *gp; 2009 2010 /* 2011 * Check to see if the UDP or TCP stack supplied us with 2012 * the PCB. If so, rather then holding a lock and looking 2013 * up the PCB, we can use the one that was supplied. 2014 */ 2015 if (inp && *lookup == 0) { 2016 INP_LOCK_ASSERT(inp); 2017 if (inp->inp_socket != NULL) { 2018 fill_ugid_cache(inp, ugp); 2019 *lookup = 1; 2020 } 2021 } 2022 /* 2023 * If we have already been here and the packet has no 2024 * PCB entry associated with it, then we can safely 2025 * assume that this is a no match. 2026 */ 2027 if (*lookup == -1) 2028 return (0); 2029 if (proto == IPPROTO_TCP) { 2030 wildcard = 0; 2031 pi = &tcbinfo; 2032 } else if (proto == IPPROTO_UDP) { 2033 wildcard = INPLOOKUP_WILDCARD; 2034 pi = &udbinfo; 2035 } else 2036 return 0; 2037 match = 0; 2038 if (*lookup == 0) { 2039 INP_INFO_RLOCK(pi); 2040 pcb = (oif) ? 2041 in_pcblookup_hash(pi, 2042 dst_ip, htons(dst_port), 2043 src_ip, htons(src_port), 2044 wildcard, oif) : 2045 in_pcblookup_hash(pi, 2046 src_ip, htons(src_port), 2047 dst_ip, htons(dst_port), 2048 wildcard, NULL); 2049 if (pcb != NULL) { 2050 INP_LOCK(pcb); 2051 if (pcb->inp_socket != NULL) { 2052 fill_ugid_cache(pcb, ugp); 2053 *lookup = 1; 2054 } 2055 INP_UNLOCK(pcb); 2056 } 2057 INP_INFO_RUNLOCK(pi); 2058 if (*lookup == 0) { 2059 /* 2060 * If the lookup did not yield any results, there 2061 * is no sense in coming back and trying again. So 2062 * we can set lookup to -1 and ensure that we wont 2063 * bother the pcb system again. 2064 */ 2065 *lookup = -1; 2066 return (0); 2067 } 2068 } 2069 if (insn->o.opcode == O_UID) 2070 match = (ugp->fw_uid == (uid_t)insn->d[0]); 2071 else if (insn->o.opcode == O_GID) { 2072 for (gp = ugp->fw_groups; 2073 gp < &ugp->fw_groups[ugp->fw_ngroups]; gp++) 2074 if (*gp == (gid_t)insn->d[0]) { 2075 match = 1; 2076 break; 2077 } 2078 } else if (insn->o.opcode == O_JAIL) 2079 match = (ugp->fw_prid == (int)insn->d[0]); 2080 return match; 2081 } 2082 2083 /* 2084 * The main check routine for the firewall. 2085 * 2086 * All arguments are in args so we can modify them and return them 2087 * back to the caller. 2088 * 2089 * Parameters: 2090 * 2091 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 2092 * Starts with the IP header. 2093 * args->eh (in) Mac header if present, or NULL for layer3 packet. 2094 * args->L3offset Number of bytes bypassed if we came from L2. 2095 * e.g. often sizeof(eh) ** NOTYET ** 2096 * args->oif Outgoing interface, or NULL if packet is incoming. 2097 * The incoming interface is in the mbuf. (in) 2098 * args->divert_rule (in/out) 2099 * Skip up to the first rule past this rule number; 2100 * upon return, non-zero port number for divert or tee. 2101 * 2102 * args->rule Pointer to the last matching rule (in/out) 2103 * args->next_hop Socket we are forwarding to (out). 2104 * args->f_id Addresses grabbed from the packet (out) 2105 * args->cookie a cookie depending on rule action 2106 * 2107 * Return value: 2108 * 2109 * IP_FW_PASS the packet must be accepted 2110 * IP_FW_DENY the packet must be dropped 2111 * IP_FW_DIVERT divert packet, port in m_tag 2112 * IP_FW_TEE tee packet, port in m_tag 2113 * IP_FW_DUMMYNET to dummynet, pipe in args->cookie 2114 * IP_FW_NETGRAPH into netgraph, cookie args->cookie 2115 * 2116 */ 2117 int 2118 ipfw_chk(struct ip_fw_args *args) 2119 { 2120 /* 2121 * Local variables holding state during the processing of a packet: 2122 * 2123 * IMPORTANT NOTE: to speed up the processing of rules, there 2124 * are some assumption on the values of the variables, which 2125 * are documented here. Should you change them, please check 2126 * the implementation of the various instructions to make sure 2127 * that they still work. 2128 * 2129 * args->eh The MAC header. It is non-null for a layer2 2130 * packet, it is NULL for a layer-3 packet. 2131 * **notyet** 2132 * args->L3offset Offset in the packet to the L3 (IP or equiv.) header. 2133 * 2134 * m | args->m Pointer to the mbuf, as received from the caller. 2135 * It may change if ipfw_chk() does an m_pullup, or if it 2136 * consumes the packet because it calls send_reject(). 2137 * XXX This has to change, so that ipfw_chk() never modifies 2138 * or consumes the buffer. 2139 * ip is the beginning of the ip(4 or 6) header. 2140 * Calculated by adding the L3offset to the start of data. 2141 * (Until we start using L3offset, the packet is 2142 * supposed to start with the ip header). 2143 */ 2144 struct mbuf *m = args->m; 2145 struct ip *ip = mtod(m, struct ip *); 2146 2147 /* 2148 * For rules which contain uid/gid or jail constraints, cache 2149 * a copy of the users credentials after the pcb lookup has been 2150 * executed. This will speed up the processing of rules with 2151 * these types of constraints, as well as decrease contention 2152 * on pcb related locks. 2153 */ 2154 struct ip_fw_ugid fw_ugid_cache; 2155 int ugid_lookup = 0; 2156 2157 /* 2158 * divinput_flags If non-zero, set to the IP_FW_DIVERT_*_FLAG 2159 * associated with a packet input on a divert socket. This 2160 * will allow to distinguish traffic and its direction when 2161 * it originates from a divert socket. 2162 */ 2163 u_int divinput_flags = 0; 2164 2165 /* 2166 * oif | args->oif If NULL, ipfw_chk has been called on the 2167 * inbound path (ether_input, bdg_forward, ip_input). 2168 * If non-NULL, ipfw_chk has been called on the outbound path 2169 * (ether_output, ip_output). 2170 */ 2171 struct ifnet *oif = args->oif; 2172 2173 struct ip_fw *f = NULL; /* matching rule */ 2174 int retval = 0; 2175 2176 /* 2177 * hlen The length of the IP header. 2178 */ 2179 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 2180 2181 /* 2182 * offset The offset of a fragment. offset != 0 means that 2183 * we have a fragment at this offset of an IPv4 packet. 2184 * offset == 0 means that (if this is an IPv4 packet) 2185 * this is the first or only fragment. 2186 * For IPv6 offset == 0 means there is no Fragment Header. 2187 * If offset != 0 for IPv6 always use correct mask to 2188 * get the correct offset because we add IP6F_MORE_FRAG 2189 * to be able to dectect the first fragment which would 2190 * otherwise have offset = 0. 2191 */ 2192 u_short offset = 0; 2193 2194 /* 2195 * Local copies of addresses. They are only valid if we have 2196 * an IP packet. 2197 * 2198 * proto The protocol. Set to 0 for non-ip packets, 2199 * or to the protocol read from the packet otherwise. 2200 * proto != 0 means that we have an IPv4 packet. 2201 * 2202 * src_port, dst_port port numbers, in HOST format. Only 2203 * valid for TCP and UDP packets. 2204 * 2205 * src_ip, dst_ip ip addresses, in NETWORK format. 2206 * Only valid for IPv4 packets. 2207 */ 2208 u_int8_t proto; 2209 u_int16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 2210 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 2211 u_int16_t ip_len=0; 2212 int pktlen; 2213 u_int16_t etype = 0; /* Host order stored ether type */ 2214 2215 /* 2216 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 2217 * MATCH_NONE when checked and not matched (q = NULL), 2218 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 2219 */ 2220 int dyn_dir = MATCH_UNKNOWN; 2221 ipfw_dyn_rule *q = NULL; 2222 struct ip_fw_chain *chain = &layer3_chain; 2223 struct m_tag *mtag; 2224 2225 /* 2226 * We store in ulp a pointer to the upper layer protocol header. 2227 * In the ipv4 case this is easy to determine from the header, 2228 * but for ipv6 we might have some additional headers in the middle. 2229 * ulp is NULL if not found. 2230 */ 2231 void *ulp = NULL; /* upper layer protocol pointer. */ 2232 /* XXX ipv6 variables */ 2233 int is_ipv6 = 0; 2234 u_int16_t ext_hd = 0; /* bits vector for extension header filtering */ 2235 /* end of ipv6 variables */ 2236 int is_ipv4 = 0; 2237 2238 if (m->m_flags & M_SKIP_FIREWALL) 2239 return (IP_FW_PASS); /* accept */ 2240 2241 pktlen = m->m_pkthdr.len; 2242 proto = args->f_id.proto = 0; /* mark f_id invalid */ 2243 /* XXX 0 is a valid proto: IP/IPv6 Hop-by-Hop Option */ 2244 2245 /* 2246 * PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous, 2247 * then it sets p to point at the offset "len" in the mbuf. WARNING: the 2248 * pointer might become stale after other pullups (but we never use it 2249 * this way). 2250 */ 2251 #define PULLUP_TO(len, p, T) \ 2252 do { \ 2253 int x = (len) + sizeof(T); \ 2254 if ((m)->m_len < x) { \ 2255 args->m = m = m_pullup(m, x); \ 2256 if (m == NULL) \ 2257 goto pullup_failed; \ 2258 } \ 2259 p = (mtod(m, char *) + (len)); \ 2260 } while (0) 2261 2262 /* 2263 * if we have an ether header, 2264 */ 2265 if (args->eh) 2266 etype = ntohs(args->eh->ether_type); 2267 2268 /* Identify IP packets and fill up variables. */ 2269 if (pktlen >= sizeof(struct ip6_hdr) && 2270 (args->eh == NULL || etype == ETHERTYPE_IPV6) && ip->ip_v == 6) { 2271 struct ip6_hdr *ip6 = (struct ip6_hdr *)ip; 2272 is_ipv6 = 1; 2273 args->f_id.addr_type = 6; 2274 hlen = sizeof(struct ip6_hdr); 2275 proto = ip6->ip6_nxt; 2276 2277 /* Search extension headers to find upper layer protocols */ 2278 while (ulp == NULL) { 2279 switch (proto) { 2280 case IPPROTO_ICMPV6: 2281 PULLUP_TO(hlen, ulp, struct icmp6_hdr); 2282 args->f_id.flags = ICMP6(ulp)->icmp6_type; 2283 break; 2284 2285 case IPPROTO_TCP: 2286 PULLUP_TO(hlen, ulp, struct tcphdr); 2287 dst_port = TCP(ulp)->th_dport; 2288 src_port = TCP(ulp)->th_sport; 2289 args->f_id.flags = TCP(ulp)->th_flags; 2290 break; 2291 2292 case IPPROTO_UDP: 2293 PULLUP_TO(hlen, ulp, struct udphdr); 2294 dst_port = UDP(ulp)->uh_dport; 2295 src_port = UDP(ulp)->uh_sport; 2296 break; 2297 2298 case IPPROTO_HOPOPTS: /* RFC 2460 */ 2299 PULLUP_TO(hlen, ulp, struct ip6_hbh); 2300 ext_hd |= EXT_HOPOPTS; 2301 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 2302 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 2303 ulp = NULL; 2304 break; 2305 2306 case IPPROTO_ROUTING: /* RFC 2460 */ 2307 PULLUP_TO(hlen, ulp, struct ip6_rthdr); 2308 switch (((struct ip6_rthdr *)ulp)->ip6r_type) { 2309 case 0: 2310 ext_hd |= EXT_RTHDR0; 2311 break; 2312 case 2: 2313 ext_hd |= EXT_RTHDR2; 2314 break; 2315 default: 2316 printf("IPFW2: IPV6 - Unknown Routing " 2317 "Header type(%d)\n", 2318 ((struct ip6_rthdr *)ulp)->ip6r_type); 2319 if (fw_deny_unknown_exthdrs) 2320 return (IP_FW_DENY); 2321 break; 2322 } 2323 ext_hd |= EXT_ROUTING; 2324 hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3; 2325 proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt; 2326 ulp = NULL; 2327 break; 2328 2329 case IPPROTO_FRAGMENT: /* RFC 2460 */ 2330 PULLUP_TO(hlen, ulp, struct ip6_frag); 2331 ext_hd |= EXT_FRAGMENT; 2332 hlen += sizeof (struct ip6_frag); 2333 proto = ((struct ip6_frag *)ulp)->ip6f_nxt; 2334 offset = ((struct ip6_frag *)ulp)->ip6f_offlg & 2335 IP6F_OFF_MASK; 2336 /* Add IP6F_MORE_FRAG for offset of first 2337 * fragment to be != 0. */ 2338 offset |= ((struct ip6_frag *)ulp)->ip6f_offlg & 2339 IP6F_MORE_FRAG; 2340 if (offset == 0) { 2341 printf("IPFW2: IPV6 - Invalid Fragment " 2342 "Header\n"); 2343 if (fw_deny_unknown_exthdrs) 2344 return (IP_FW_DENY); 2345 break; 2346 } 2347 args->f_id.frag_id6 = 2348 ntohl(((struct ip6_frag *)ulp)->ip6f_ident); 2349 ulp = NULL; 2350 break; 2351 2352 case IPPROTO_DSTOPTS: /* RFC 2460 */ 2353 PULLUP_TO(hlen, ulp, struct ip6_hbh); 2354 ext_hd |= EXT_DSTOPTS; 2355 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 2356 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 2357 ulp = NULL; 2358 break; 2359 2360 case IPPROTO_AH: /* RFC 2402 */ 2361 PULLUP_TO(hlen, ulp, struct ip6_ext); 2362 ext_hd |= EXT_AH; 2363 hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2; 2364 proto = ((struct ip6_ext *)ulp)->ip6e_nxt; 2365 ulp = NULL; 2366 break; 2367 2368 case IPPROTO_ESP: /* RFC 2406 */ 2369 PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */ 2370 /* Anything past Seq# is variable length and 2371 * data past this ext. header is encrypted. */ 2372 ext_hd |= EXT_ESP; 2373 break; 2374 2375 case IPPROTO_NONE: /* RFC 2460 */ 2376 /* 2377 * Packet ends here, and IPv6 header has 2378 * already been pulled up. If ip6e_len!=0 2379 * then octets must be ignored. 2380 */ 2381 ulp = ip; /* non-NULL to get out of loop. */ 2382 break; 2383 2384 case IPPROTO_OSPFIGP: 2385 /* XXX OSPF header check? */ 2386 PULLUP_TO(hlen, ulp, struct ip6_ext); 2387 break; 2388 2389 case IPPROTO_PIM: 2390 /* XXX PIM header check? */ 2391 PULLUP_TO(hlen, ulp, struct pim); 2392 break; 2393 2394 case IPPROTO_CARP: 2395 PULLUP_TO(hlen, ulp, struct carp_header); 2396 if (((struct carp_header *)ulp)->carp_version != 2397 CARP_VERSION) 2398 return (IP_FW_DENY); 2399 if (((struct carp_header *)ulp)->carp_type != 2400 CARP_ADVERTISEMENT) 2401 return (IP_FW_DENY); 2402 break; 2403 2404 case IPPROTO_IPV6: /* RFC 2893 */ 2405 PULLUP_TO(hlen, ulp, struct ip6_hdr); 2406 break; 2407 2408 case IPPROTO_IPV4: /* RFC 2893 */ 2409 PULLUP_TO(hlen, ulp, struct ip); 2410 break; 2411 2412 default: 2413 printf("IPFW2: IPV6 - Unknown Extension " 2414 "Header(%d), ext_hd=%x\n", proto, ext_hd); 2415 if (fw_deny_unknown_exthdrs) 2416 return (IP_FW_DENY); 2417 PULLUP_TO(hlen, ulp, struct ip6_ext); 2418 break; 2419 } /*switch */ 2420 } 2421 ip = mtod(m, struct ip *); 2422 ip6 = (struct ip6_hdr *)ip; 2423 args->f_id.src_ip6 = ip6->ip6_src; 2424 args->f_id.dst_ip6 = ip6->ip6_dst; 2425 args->f_id.src_ip = 0; 2426 args->f_id.dst_ip = 0; 2427 args->f_id.flow_id6 = ntohl(ip6->ip6_flow); 2428 } else if (pktlen >= sizeof(struct ip) && 2429 (args->eh == NULL || etype == ETHERTYPE_IP) && ip->ip_v == 4) { 2430 is_ipv4 = 1; 2431 hlen = ip->ip_hl << 2; 2432 args->f_id.addr_type = 4; 2433 2434 /* 2435 * Collect parameters into local variables for faster matching. 2436 */ 2437 proto = ip->ip_p; 2438 src_ip = ip->ip_src; 2439 dst_ip = ip->ip_dst; 2440 if (args->eh != NULL) { /* layer 2 packets are as on the wire */ 2441 offset = ntohs(ip->ip_off) & IP_OFFMASK; 2442 ip_len = ntohs(ip->ip_len); 2443 } else { 2444 offset = ip->ip_off & IP_OFFMASK; 2445 ip_len = ip->ip_len; 2446 } 2447 pktlen = ip_len < pktlen ? ip_len : pktlen; 2448 2449 if (offset == 0) { 2450 switch (proto) { 2451 case IPPROTO_TCP: 2452 PULLUP_TO(hlen, ulp, struct tcphdr); 2453 dst_port = TCP(ulp)->th_dport; 2454 src_port = TCP(ulp)->th_sport; 2455 args->f_id.flags = TCP(ulp)->th_flags; 2456 break; 2457 2458 case IPPROTO_UDP: 2459 PULLUP_TO(hlen, ulp, struct udphdr); 2460 dst_port = UDP(ulp)->uh_dport; 2461 src_port = UDP(ulp)->uh_sport; 2462 break; 2463 2464 case IPPROTO_ICMP: 2465 PULLUP_TO(hlen, ulp, struct icmphdr); 2466 args->f_id.flags = ICMP(ulp)->icmp_type; 2467 break; 2468 2469 default: 2470 break; 2471 } 2472 } 2473 2474 ip = mtod(m, struct ip *); 2475 args->f_id.src_ip = ntohl(src_ip.s_addr); 2476 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 2477 } 2478 #undef PULLUP_TO 2479 if (proto) { /* we may have port numbers, store them */ 2480 args->f_id.proto = proto; 2481 args->f_id.src_port = src_port = ntohs(src_port); 2482 args->f_id.dst_port = dst_port = ntohs(dst_port); 2483 } 2484 2485 IPFW_RLOCK(chain); 2486 mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL); 2487 if (args->rule) { 2488 /* 2489 * Packet has already been tagged. Look for the next rule 2490 * to restart processing. 2491 * 2492 * If fw_one_pass != 0 then just accept it. 2493 * XXX should not happen here, but optimized out in 2494 * the caller. 2495 */ 2496 if (fw_one_pass) { 2497 IPFW_RUNLOCK(chain); 2498 return (IP_FW_PASS); 2499 } 2500 2501 f = args->rule->next_rule; 2502 if (f == NULL) 2503 f = lookup_next_rule(args->rule); 2504 } else { 2505 /* 2506 * Find the starting rule. It can be either the first 2507 * one, or the one after divert_rule if asked so. 2508 */ 2509 int skipto = mtag ? divert_cookie(mtag) : 0; 2510 2511 f = chain->rules; 2512 if (args->eh == NULL && skipto != 0) { 2513 if (skipto >= IPFW_DEFAULT_RULE) { 2514 IPFW_RUNLOCK(chain); 2515 return (IP_FW_DENY); /* invalid */ 2516 } 2517 while (f && f->rulenum <= skipto) 2518 f = f->next; 2519 if (f == NULL) { /* drop packet */ 2520 IPFW_RUNLOCK(chain); 2521 return (IP_FW_DENY); 2522 } 2523 } 2524 } 2525 /* reset divert rule to avoid confusion later */ 2526 if (mtag) { 2527 divinput_flags = divert_info(mtag) & 2528 (IP_FW_DIVERT_OUTPUT_FLAG | IP_FW_DIVERT_LOOPBACK_FLAG); 2529 m_tag_delete(m, mtag); 2530 } 2531 2532 /* 2533 * Now scan the rules, and parse microinstructions for each rule. 2534 */ 2535 for (; f; f = f->next) { 2536 ipfw_insn *cmd; 2537 uint32_t tablearg = 0; 2538 int l, cmdlen, skip_or; /* skip rest of OR block */ 2539 2540 again: 2541 if (set_disable & (1 << f->set) ) 2542 continue; 2543 2544 skip_or = 0; 2545 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 2546 l -= cmdlen, cmd += cmdlen) { 2547 int match; 2548 2549 /* 2550 * check_body is a jump target used when we find a 2551 * CHECK_STATE, and need to jump to the body of 2552 * the target rule. 2553 */ 2554 2555 check_body: 2556 cmdlen = F_LEN(cmd); 2557 /* 2558 * An OR block (insn_1 || .. || insn_n) has the 2559 * F_OR bit set in all but the last instruction. 2560 * The first match will set "skip_or", and cause 2561 * the following instructions to be skipped until 2562 * past the one with the F_OR bit clear. 2563 */ 2564 if (skip_or) { /* skip this instruction */ 2565 if ((cmd->len & F_OR) == 0) 2566 skip_or = 0; /* next one is good */ 2567 continue; 2568 } 2569 match = 0; /* set to 1 if we succeed */ 2570 2571 switch (cmd->opcode) { 2572 /* 2573 * The first set of opcodes compares the packet's 2574 * fields with some pattern, setting 'match' if a 2575 * match is found. At the end of the loop there is 2576 * logic to deal with F_NOT and F_OR flags associated 2577 * with the opcode. 2578 */ 2579 case O_NOP: 2580 match = 1; 2581 break; 2582 2583 case O_FORWARD_MAC: 2584 printf("ipfw: opcode %d unimplemented\n", 2585 cmd->opcode); 2586 break; 2587 2588 case O_GID: 2589 case O_UID: 2590 case O_JAIL: 2591 /* 2592 * We only check offset == 0 && proto != 0, 2593 * as this ensures that we have a 2594 * packet with the ports info. 2595 */ 2596 if (offset!=0) 2597 break; 2598 if (is_ipv6) /* XXX to be fixed later */ 2599 break; 2600 if (proto == IPPROTO_TCP || 2601 proto == IPPROTO_UDP) 2602 match = check_uidgid( 2603 (ipfw_insn_u32 *)cmd, 2604 proto, oif, 2605 dst_ip, dst_port, 2606 src_ip, src_port, &fw_ugid_cache, 2607 &ugid_lookup, args->inp); 2608 break; 2609 2610 case O_RECV: 2611 match = iface_match(m->m_pkthdr.rcvif, 2612 (ipfw_insn_if *)cmd); 2613 break; 2614 2615 case O_XMIT: 2616 match = iface_match(oif, (ipfw_insn_if *)cmd); 2617 break; 2618 2619 case O_VIA: 2620 match = iface_match(oif ? oif : 2621 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd); 2622 break; 2623 2624 case O_MACADDR2: 2625 if (args->eh != NULL) { /* have MAC header */ 2626 u_int32_t *want = (u_int32_t *) 2627 ((ipfw_insn_mac *)cmd)->addr; 2628 u_int32_t *mask = (u_int32_t *) 2629 ((ipfw_insn_mac *)cmd)->mask; 2630 u_int32_t *hdr = (u_int32_t *)args->eh; 2631 2632 match = 2633 ( want[0] == (hdr[0] & mask[0]) && 2634 want[1] == (hdr[1] & mask[1]) && 2635 want[2] == (hdr[2] & mask[2]) ); 2636 } 2637 break; 2638 2639 case O_MAC_TYPE: 2640 if (args->eh != NULL) { 2641 u_int16_t *p = 2642 ((ipfw_insn_u16 *)cmd)->ports; 2643 int i; 2644 2645 for (i = cmdlen - 1; !match && i>0; 2646 i--, p += 2) 2647 match = (etype >= p[0] && 2648 etype <= p[1]); 2649 } 2650 break; 2651 2652 case O_FRAG: 2653 match = (offset != 0); 2654 break; 2655 2656 case O_IN: /* "out" is "not in" */ 2657 match = (oif == NULL); 2658 break; 2659 2660 case O_LAYER2: 2661 match = (args->eh != NULL); 2662 break; 2663 2664 case O_DIVERTED: 2665 match = (cmd->arg1 & 1 && divinput_flags & 2666 IP_FW_DIVERT_LOOPBACK_FLAG) || 2667 (cmd->arg1 & 2 && divinput_flags & 2668 IP_FW_DIVERT_OUTPUT_FLAG); 2669 break; 2670 2671 case O_PROTO: 2672 /* 2673 * We do not allow an arg of 0 so the 2674 * check of "proto" only suffices. 2675 */ 2676 match = (proto == cmd->arg1); 2677 break; 2678 2679 case O_IP_SRC: 2680 match = is_ipv4 && 2681 (((ipfw_insn_ip *)cmd)->addr.s_addr == 2682 src_ip.s_addr); 2683 break; 2684 2685 case O_IP_SRC_LOOKUP: 2686 case O_IP_DST_LOOKUP: 2687 if (is_ipv4) { 2688 uint32_t a = 2689 (cmd->opcode == O_IP_DST_LOOKUP) ? 2690 dst_ip.s_addr : src_ip.s_addr; 2691 uint32_t v; 2692 2693 match = lookup_table(chain, cmd->arg1, a, 2694 &v); 2695 if (!match) 2696 break; 2697 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 2698 match = 2699 ((ipfw_insn_u32 *)cmd)->d[0] == v; 2700 else 2701 tablearg = v; 2702 } 2703 break; 2704 2705 case O_IP_SRC_MASK: 2706 case O_IP_DST_MASK: 2707 if (is_ipv4) { 2708 uint32_t a = 2709 (cmd->opcode == O_IP_DST_MASK) ? 2710 dst_ip.s_addr : src_ip.s_addr; 2711 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 2712 int i = cmdlen-1; 2713 2714 for (; !match && i>0; i-= 2, p+= 2) 2715 match = (p[0] == (a & p[1])); 2716 } 2717 break; 2718 2719 case O_IP_SRC_ME: 2720 if (is_ipv4) { 2721 struct ifnet *tif; 2722 2723 INADDR_TO_IFP(src_ip, tif); 2724 match = (tif != NULL); 2725 } 2726 break; 2727 2728 case O_IP_DST_SET: 2729 case O_IP_SRC_SET: 2730 if (is_ipv4) { 2731 u_int32_t *d = (u_int32_t *)(cmd+1); 2732 u_int32_t addr = 2733 cmd->opcode == O_IP_DST_SET ? 2734 args->f_id.dst_ip : 2735 args->f_id.src_ip; 2736 2737 if (addr < d[0]) 2738 break; 2739 addr -= d[0]; /* subtract base */ 2740 match = (addr < cmd->arg1) && 2741 ( d[ 1 + (addr>>5)] & 2742 (1<<(addr & 0x1f)) ); 2743 } 2744 break; 2745 2746 case O_IP_DST: 2747 match = is_ipv4 && 2748 (((ipfw_insn_ip *)cmd)->addr.s_addr == 2749 dst_ip.s_addr); 2750 break; 2751 2752 case O_IP_DST_ME: 2753 if (is_ipv4) { 2754 struct ifnet *tif; 2755 2756 INADDR_TO_IFP(dst_ip, tif); 2757 match = (tif != NULL); 2758 } 2759 break; 2760 2761 case O_IP_SRCPORT: 2762 case O_IP_DSTPORT: 2763 /* 2764 * offset == 0 && proto != 0 is enough 2765 * to guarantee that we have a 2766 * packet with port info. 2767 */ 2768 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP) 2769 && offset == 0) { 2770 u_int16_t x = 2771 (cmd->opcode == O_IP_SRCPORT) ? 2772 src_port : dst_port ; 2773 u_int16_t *p = 2774 ((ipfw_insn_u16 *)cmd)->ports; 2775 int i; 2776 2777 for (i = cmdlen - 1; !match && i>0; 2778 i--, p += 2) 2779 match = (x>=p[0] && x<=p[1]); 2780 } 2781 break; 2782 2783 case O_ICMPTYPE: 2784 match = (offset == 0 && proto==IPPROTO_ICMP && 2785 icmptype_match(ICMP(ulp), (ipfw_insn_u32 *)cmd) ); 2786 break; 2787 2788 #ifdef INET6 2789 case O_ICMP6TYPE: 2790 match = is_ipv6 && offset == 0 && 2791 proto==IPPROTO_ICMPV6 && 2792 icmp6type_match( 2793 ICMP6(ulp)->icmp6_type, 2794 (ipfw_insn_u32 *)cmd); 2795 break; 2796 #endif /* INET6 */ 2797 2798 case O_IPOPT: 2799 match = (is_ipv4 && 2800 ipopts_match(ip, cmd) ); 2801 break; 2802 2803 case O_IPVER: 2804 match = (is_ipv4 && 2805 cmd->arg1 == ip->ip_v); 2806 break; 2807 2808 case O_IPID: 2809 case O_IPLEN: 2810 case O_IPTTL: 2811 if (is_ipv4) { /* only for IP packets */ 2812 uint16_t x; 2813 uint16_t *p; 2814 int i; 2815 2816 if (cmd->opcode == O_IPLEN) 2817 x = ip_len; 2818 else if (cmd->opcode == O_IPTTL) 2819 x = ip->ip_ttl; 2820 else /* must be IPID */ 2821 x = ntohs(ip->ip_id); 2822 if (cmdlen == 1) { 2823 match = (cmd->arg1 == x); 2824 break; 2825 } 2826 /* otherwise we have ranges */ 2827 p = ((ipfw_insn_u16 *)cmd)->ports; 2828 i = cmdlen - 1; 2829 for (; !match && i>0; i--, p += 2) 2830 match = (x >= p[0] && x <= p[1]); 2831 } 2832 break; 2833 2834 case O_IPPRECEDENCE: 2835 match = (is_ipv4 && 2836 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 2837 break; 2838 2839 case O_IPTOS: 2840 match = (is_ipv4 && 2841 flags_match(cmd, ip->ip_tos)); 2842 break; 2843 2844 case O_TCPDATALEN: 2845 if (proto == IPPROTO_TCP && offset == 0) { 2846 struct tcphdr *tcp; 2847 uint16_t x; 2848 uint16_t *p; 2849 int i; 2850 2851 tcp = TCP(ulp); 2852 x = ip_len - 2853 ((ip->ip_hl + tcp->th_off) << 2); 2854 if (cmdlen == 1) { 2855 match = (cmd->arg1 == x); 2856 break; 2857 } 2858 /* otherwise we have ranges */ 2859 p = ((ipfw_insn_u16 *)cmd)->ports; 2860 i = cmdlen - 1; 2861 for (; !match && i>0; i--, p += 2) 2862 match = (x >= p[0] && x <= p[1]); 2863 } 2864 break; 2865 2866 case O_TCPFLAGS: 2867 match = (proto == IPPROTO_TCP && offset == 0 && 2868 flags_match(cmd, TCP(ulp)->th_flags)); 2869 break; 2870 2871 case O_TCPOPTS: 2872 match = (proto == IPPROTO_TCP && offset == 0 && 2873 tcpopts_match(TCP(ulp), cmd)); 2874 break; 2875 2876 case O_TCPSEQ: 2877 match = (proto == IPPROTO_TCP && offset == 0 && 2878 ((ipfw_insn_u32 *)cmd)->d[0] == 2879 TCP(ulp)->th_seq); 2880 break; 2881 2882 case O_TCPACK: 2883 match = (proto == IPPROTO_TCP && offset == 0 && 2884 ((ipfw_insn_u32 *)cmd)->d[0] == 2885 TCP(ulp)->th_ack); 2886 break; 2887 2888 case O_TCPWIN: 2889 match = (proto == IPPROTO_TCP && offset == 0 && 2890 cmd->arg1 == TCP(ulp)->th_win); 2891 break; 2892 2893 case O_ESTAB: 2894 /* reject packets which have SYN only */ 2895 /* XXX should i also check for TH_ACK ? */ 2896 match = (proto == IPPROTO_TCP && offset == 0 && 2897 (TCP(ulp)->th_flags & 2898 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 2899 break; 2900 2901 case O_ALTQ: { 2902 struct altq_tag *at; 2903 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 2904 2905 match = 1; 2906 mtag = m_tag_find(m, PACKET_TAG_PF_QID, NULL); 2907 if (mtag != NULL) 2908 break; 2909 mtag = m_tag_get(PACKET_TAG_PF_QID, 2910 sizeof(struct altq_tag), 2911 M_NOWAIT); 2912 if (mtag == NULL) { 2913 /* 2914 * Let the packet fall back to the 2915 * default ALTQ. 2916 */ 2917 break; 2918 } 2919 at = (struct altq_tag *)(mtag+1); 2920 at->qid = altq->qid; 2921 if (is_ipv4) 2922 at->af = AF_INET; 2923 else 2924 at->af = AF_LINK; 2925 at->hdr = ip; 2926 m_tag_prepend(m, mtag); 2927 break; 2928 } 2929 2930 case O_LOG: 2931 if (fw_verbose) 2932 ipfw_log(f, hlen, args, m, 2933 oif, offset, tablearg, ip); 2934 match = 1; 2935 break; 2936 2937 case O_PROB: 2938 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 2939 break; 2940 2941 case O_VERREVPATH: 2942 /* Outgoing packets automatically pass/match */ 2943 match = ((oif != NULL) || 2944 (m->m_pkthdr.rcvif == NULL) || 2945 ( 2946 #ifdef INET6 2947 is_ipv6 ? 2948 verify_path6(&(args->f_id.src_ip6), 2949 m->m_pkthdr.rcvif) : 2950 #endif 2951 verify_path(src_ip, m->m_pkthdr.rcvif))); 2952 break; 2953 2954 case O_VERSRCREACH: 2955 /* Outgoing packets automatically pass/match */ 2956 match = (hlen > 0 && ((oif != NULL) || 2957 #ifdef INET6 2958 is_ipv6 ? 2959 verify_path6(&(args->f_id.src_ip6), 2960 NULL) : 2961 #endif 2962 verify_path(src_ip, NULL))); 2963 break; 2964 2965 case O_ANTISPOOF: 2966 /* Outgoing packets automatically pass/match */ 2967 if (oif == NULL && hlen > 0 && 2968 ( (is_ipv4 && in_localaddr(src_ip)) 2969 #ifdef INET6 2970 || (is_ipv6 && 2971 in6_localaddr(&(args->f_id.src_ip6))) 2972 #endif 2973 )) 2974 match = 2975 #ifdef INET6 2976 is_ipv6 ? verify_path6( 2977 &(args->f_id.src_ip6), 2978 m->m_pkthdr.rcvif) : 2979 #endif 2980 verify_path(src_ip, 2981 m->m_pkthdr.rcvif); 2982 else 2983 match = 1; 2984 break; 2985 2986 case O_IPSEC: 2987 #ifdef FAST_IPSEC 2988 match = (m_tag_find(m, 2989 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 2990 #endif 2991 #ifdef IPSEC 2992 match = (ipsec_getnhist(m) != 0); 2993 #endif 2994 /* otherwise no match */ 2995 break; 2996 2997 #ifdef INET6 2998 case O_IP6_SRC: 2999 match = is_ipv6 && 3000 IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6, 3001 &((ipfw_insn_ip6 *)cmd)->addr6); 3002 break; 3003 3004 case O_IP6_DST: 3005 match = is_ipv6 && 3006 IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6, 3007 &((ipfw_insn_ip6 *)cmd)->addr6); 3008 break; 3009 case O_IP6_SRC_MASK: 3010 case O_IP6_DST_MASK: 3011 if (is_ipv6) { 3012 int i = cmdlen - 1; 3013 struct in6_addr p; 3014 struct in6_addr *d = 3015 &((ipfw_insn_ip6 *)cmd)->addr6; 3016 3017 for (; !match && i > 0; d += 2, 3018 i -= F_INSN_SIZE(struct in6_addr) 3019 * 2) { 3020 p = (cmd->opcode == 3021 O_IP6_SRC_MASK) ? 3022 args->f_id.src_ip6: 3023 args->f_id.dst_ip6; 3024 APPLY_MASK(&p, &d[1]); 3025 match = 3026 IN6_ARE_ADDR_EQUAL(&d[0], 3027 &p); 3028 } 3029 } 3030 break; 3031 3032 case O_IP6_SRC_ME: 3033 match= is_ipv6 && search_ip6_addr_net(&args->f_id.src_ip6); 3034 break; 3035 3036 case O_IP6_DST_ME: 3037 match= is_ipv6 && search_ip6_addr_net(&args->f_id.dst_ip6); 3038 break; 3039 3040 case O_FLOW6ID: 3041 match = is_ipv6 && 3042 flow6id_match(args->f_id.flow_id6, 3043 (ipfw_insn_u32 *) cmd); 3044 break; 3045 3046 case O_EXT_HDR: 3047 match = is_ipv6 && 3048 (ext_hd & ((ipfw_insn *) cmd)->arg1); 3049 break; 3050 3051 case O_IP6: 3052 match = is_ipv6; 3053 break; 3054 #endif 3055 3056 case O_IP4: 3057 match = is_ipv4; 3058 break; 3059 3060 case O_TAG: { 3061 uint32_t tag = (cmd->arg1 == IP_FW_TABLEARG) ? 3062 tablearg : cmd->arg1; 3063 3064 /* Packet is already tagged with this tag? */ 3065 mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL); 3066 3067 /* We have `untag' action when F_NOT flag is 3068 * present. And we must remove this mtag from 3069 * mbuf and reset `match' to zero (`match' will 3070 * be inversed later). 3071 * Otherwise we should allocate new mtag and 3072 * push it into mbuf. 3073 */ 3074 if (cmd->len & F_NOT) { /* `untag' action */ 3075 if (mtag != NULL) 3076 m_tag_delete(m, mtag); 3077 } else if (mtag == NULL) { 3078 if ((mtag = m_tag_alloc(MTAG_IPFW, 3079 tag, 0, M_NOWAIT)) != NULL) 3080 m_tag_prepend(m, mtag); 3081 } 3082 match = (cmd->len & F_NOT) ? 0: 1; 3083 break; 3084 } 3085 3086 case O_TAGGED: { 3087 uint32_t tag = (cmd->arg1 == IP_FW_TABLEARG) ? 3088 tablearg : cmd->arg1; 3089 3090 if (cmdlen == 1) { 3091 match = m_tag_locate(m, MTAG_IPFW, 3092 tag, NULL) != NULL; 3093 break; 3094 } 3095 3096 /* we have ranges */ 3097 for (mtag = m_tag_first(m); 3098 mtag != NULL && !match; 3099 mtag = m_tag_next(m, mtag)) { 3100 uint16_t *p; 3101 int i; 3102 3103 if (mtag->m_tag_cookie != MTAG_IPFW) 3104 continue; 3105 3106 p = ((ipfw_insn_u16 *)cmd)->ports; 3107 i = cmdlen - 1; 3108 for(; !match && i > 0; i--, p += 2) 3109 match = 3110 mtag->m_tag_id >= p[0] && 3111 mtag->m_tag_id <= p[1]; 3112 } 3113 break; 3114 } 3115 3116 /* 3117 * The second set of opcodes represents 'actions', 3118 * i.e. the terminal part of a rule once the packet 3119 * matches all previous patterns. 3120 * Typically there is only one action for each rule, 3121 * and the opcode is stored at the end of the rule 3122 * (but there are exceptions -- see below). 3123 * 3124 * In general, here we set retval and terminate the 3125 * outer loop (would be a 'break 3' in some language, 3126 * but we need to do a 'goto done'). 3127 * 3128 * Exceptions: 3129 * O_COUNT and O_SKIPTO actions: 3130 * instead of terminating, we jump to the next rule 3131 * ('goto next_rule', equivalent to a 'break 2'), 3132 * or to the SKIPTO target ('goto again' after 3133 * having set f, cmd and l), respectively. 3134 * 3135 * O_TAG, O_LOG and O_ALTQ action parameters: 3136 * perform some action and set match = 1; 3137 * 3138 * O_LIMIT and O_KEEP_STATE: these opcodes are 3139 * not real 'actions', and are stored right 3140 * before the 'action' part of the rule. 3141 * These opcodes try to install an entry in the 3142 * state tables; if successful, we continue with 3143 * the next opcode (match=1; break;), otherwise 3144 * the packet * must be dropped 3145 * ('goto done' after setting retval); 3146 * 3147 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 3148 * cause a lookup of the state table, and a jump 3149 * to the 'action' part of the parent rule 3150 * ('goto check_body') if an entry is found, or 3151 * (CHECK_STATE only) a jump to the next rule if 3152 * the entry is not found ('goto next_rule'). 3153 * The result of the lookup is cached to make 3154 * further instances of these opcodes are 3155 * effectively NOPs. 3156 */ 3157 case O_LIMIT: 3158 case O_KEEP_STATE: 3159 if (install_state(f, 3160 (ipfw_insn_limit *)cmd, args, tablearg)) { 3161 retval = IP_FW_DENY; 3162 goto done; /* error/limit violation */ 3163 } 3164 match = 1; 3165 break; 3166 3167 case O_PROBE_STATE: 3168 case O_CHECK_STATE: 3169 /* 3170 * dynamic rules are checked at the first 3171 * keep-state or check-state occurrence, 3172 * with the result being stored in dyn_dir. 3173 * The compiler introduces a PROBE_STATE 3174 * instruction for us when we have a 3175 * KEEP_STATE (because PROBE_STATE needs 3176 * to be run first). 3177 */ 3178 if (dyn_dir == MATCH_UNKNOWN && 3179 (q = lookup_dyn_rule(&args->f_id, 3180 &dyn_dir, proto == IPPROTO_TCP ? 3181 TCP(ulp) : NULL)) 3182 != NULL) { 3183 /* 3184 * Found dynamic entry, update stats 3185 * and jump to the 'action' part of 3186 * the parent rule. 3187 */ 3188 q->pcnt++; 3189 q->bcnt += pktlen; 3190 f = q->rule; 3191 cmd = ACTION_PTR(f); 3192 l = f->cmd_len - f->act_ofs; 3193 IPFW_DYN_UNLOCK(); 3194 goto check_body; 3195 } 3196 /* 3197 * Dynamic entry not found. If CHECK_STATE, 3198 * skip to next rule, if PROBE_STATE just 3199 * ignore and continue with next opcode. 3200 */ 3201 if (cmd->opcode == O_CHECK_STATE) 3202 goto next_rule; 3203 match = 1; 3204 break; 3205 3206 case O_ACCEPT: 3207 retval = 0; /* accept */ 3208 goto done; 3209 3210 case O_PIPE: 3211 case O_QUEUE: 3212 args->rule = f; /* report matching rule */ 3213 if (cmd->arg1 == IP_FW_TABLEARG) 3214 args->cookie = tablearg; 3215 else 3216 args->cookie = cmd->arg1; 3217 retval = IP_FW_DUMMYNET; 3218 goto done; 3219 3220 case O_DIVERT: 3221 case O_TEE: { 3222 struct divert_tag *dt; 3223 3224 if (args->eh) /* not on layer 2 */ 3225 break; 3226 mtag = m_tag_get(PACKET_TAG_DIVERT, 3227 sizeof(struct divert_tag), 3228 M_NOWAIT); 3229 if (mtag == NULL) { 3230 /* XXX statistic */ 3231 /* drop packet */ 3232 IPFW_RUNLOCK(chain); 3233 return (IP_FW_DENY); 3234 } 3235 dt = (struct divert_tag *)(mtag+1); 3236 dt->cookie = f->rulenum; 3237 if (cmd->arg1 == IP_FW_TABLEARG) 3238 dt->info = tablearg; 3239 else 3240 dt->info = cmd->arg1; 3241 m_tag_prepend(m, mtag); 3242 retval = (cmd->opcode == O_DIVERT) ? 3243 IP_FW_DIVERT : IP_FW_TEE; 3244 goto done; 3245 } 3246 3247 case O_COUNT: 3248 case O_SKIPTO: 3249 f->pcnt++; /* update stats */ 3250 f->bcnt += pktlen; 3251 f->timestamp = time_uptime; 3252 if (cmd->opcode == O_COUNT) 3253 goto next_rule; 3254 /* handle skipto */ 3255 if (f->next_rule == NULL) 3256 lookup_next_rule(f); 3257 f = f->next_rule; 3258 goto again; 3259 3260 case O_REJECT: 3261 /* 3262 * Drop the packet and send a reject notice 3263 * if the packet is not ICMP (or is an ICMP 3264 * query), and it is not multicast/broadcast. 3265 */ 3266 if (hlen > 0 && is_ipv4 && offset == 0 && 3267 (proto != IPPROTO_ICMP || 3268 is_icmp_query(ICMP(ulp))) && 3269 !(m->m_flags & (M_BCAST|M_MCAST)) && 3270 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 3271 send_reject(args, cmd->arg1, 3272 offset,ip_len, ip); 3273 m = args->m; 3274 } 3275 /* FALLTHROUGH */ 3276 #ifdef INET6 3277 case O_UNREACH6: 3278 if (hlen > 0 && is_ipv6 && 3279 (proto != IPPROTO_ICMPV6 || 3280 (is_icmp6_query(args->f_id.flags) == 1)) && 3281 !(m->m_flags & (M_BCAST|M_MCAST)) && 3282 !IN6_IS_ADDR_MULTICAST(&args->f_id.dst_ip6)) { 3283 send_reject6(args, cmd->arg1, 3284 offset, hlen, (struct ip6_hdr *)ip); 3285 m = args->m; 3286 } 3287 /* FALLTHROUGH */ 3288 #endif 3289 case O_DENY: 3290 retval = IP_FW_DENY; 3291 goto done; 3292 3293 case O_FORWARD_IP: { 3294 struct sockaddr_in *sa; 3295 sa = &(((ipfw_insn_sa *)cmd)->sa); 3296 if (args->eh) /* not valid on layer2 pkts */ 3297 break; 3298 if (!q || dyn_dir == MATCH_FORWARD) { 3299 if (sa->sin_addr.s_addr == INADDR_ANY) { 3300 bcopy(sa, &args->hopstore, 3301 sizeof(*sa)); 3302 args->hopstore.sin_addr.s_addr = 3303 htonl(tablearg); 3304 args->next_hop = 3305 &args->hopstore; 3306 } else { 3307 args->next_hop = sa; 3308 } 3309 } 3310 retval = IP_FW_PASS; 3311 } 3312 goto done; 3313 3314 case O_NETGRAPH: 3315 case O_NGTEE: 3316 args->rule = f; /* report matching rule */ 3317 if (cmd->arg1 == IP_FW_TABLEARG) 3318 args->cookie = tablearg; 3319 else 3320 args->cookie = cmd->arg1; 3321 retval = (cmd->opcode == O_NETGRAPH) ? 3322 IP_FW_NETGRAPH : IP_FW_NGTEE; 3323 goto done; 3324 3325 default: 3326 panic("-- unknown opcode %d\n", cmd->opcode); 3327 } /* end of switch() on opcodes */ 3328 3329 if (cmd->len & F_NOT) 3330 match = !match; 3331 3332 if (match) { 3333 if (cmd->len & F_OR) 3334 skip_or = 1; 3335 } else { 3336 if (!(cmd->len & F_OR)) /* not an OR block, */ 3337 break; /* try next rule */ 3338 } 3339 3340 } /* end of inner for, scan opcodes */ 3341 3342 next_rule:; /* try next rule */ 3343 3344 } /* end of outer for, scan rules */ 3345 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 3346 IPFW_RUNLOCK(chain); 3347 return (IP_FW_DENY); 3348 3349 done: 3350 /* Update statistics */ 3351 f->pcnt++; 3352 f->bcnt += pktlen; 3353 f->timestamp = time_uptime; 3354 IPFW_RUNLOCK(chain); 3355 return (retval); 3356 3357 pullup_failed: 3358 if (fw_verbose) 3359 printf("ipfw: pullup failed\n"); 3360 return (IP_FW_DENY); 3361 } 3362 3363 /* 3364 * When a rule is added/deleted, clear the next_rule pointers in all rules. 3365 * These will be reconstructed on the fly as packets are matched. 3366 */ 3367 static void 3368 flush_rule_ptrs(struct ip_fw_chain *chain) 3369 { 3370 struct ip_fw *rule; 3371 3372 IPFW_WLOCK_ASSERT(chain); 3373 3374 for (rule = chain->rules; rule; rule = rule->next) 3375 rule->next_rule = NULL; 3376 } 3377 3378 /* 3379 * Add a new rule to the list. Copy the rule into a malloc'ed area, then 3380 * possibly create a rule number and add the rule to the list. 3381 * Update the rule_number in the input struct so the caller knows it as well. 3382 */ 3383 static int 3384 add_rule(struct ip_fw_chain *chain, struct ip_fw *input_rule) 3385 { 3386 struct ip_fw *rule, *f, *prev; 3387 int l = RULESIZE(input_rule); 3388 3389 if (chain->rules == NULL && input_rule->rulenum != IPFW_DEFAULT_RULE) 3390 return (EINVAL); 3391 3392 rule = malloc(l, M_IPFW, M_NOWAIT | M_ZERO); 3393 if (rule == NULL) 3394 return (ENOSPC); 3395 3396 bcopy(input_rule, rule, l); 3397 3398 rule->next = NULL; 3399 rule->next_rule = NULL; 3400 3401 rule->pcnt = 0; 3402 rule->bcnt = 0; 3403 rule->timestamp = 0; 3404 3405 IPFW_WLOCK(chain); 3406 3407 if (chain->rules == NULL) { /* default rule */ 3408 chain->rules = rule; 3409 goto done; 3410 } 3411 3412 /* 3413 * If rulenum is 0, find highest numbered rule before the 3414 * default rule, and add autoinc_step 3415 */ 3416 if (autoinc_step < 1) 3417 autoinc_step = 1; 3418 else if (autoinc_step > 1000) 3419 autoinc_step = 1000; 3420 if (rule->rulenum == 0) { 3421 /* 3422 * locate the highest numbered rule before default 3423 */ 3424 for (f = chain->rules; f; f = f->next) { 3425 if (f->rulenum == IPFW_DEFAULT_RULE) 3426 break; 3427 rule->rulenum = f->rulenum; 3428 } 3429 if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step) 3430 rule->rulenum += autoinc_step; 3431 input_rule->rulenum = rule->rulenum; 3432 } 3433 3434 /* 3435 * Now insert the new rule in the right place in the sorted list. 3436 */ 3437 for (prev = NULL, f = chain->rules; f; prev = f, f = f->next) { 3438 if (f->rulenum > rule->rulenum) { /* found the location */ 3439 if (prev) { 3440 rule->next = f; 3441 prev->next = rule; 3442 } else { /* head insert */ 3443 rule->next = chain->rules; 3444 chain->rules = rule; 3445 } 3446 break; 3447 } 3448 } 3449 flush_rule_ptrs(chain); 3450 done: 3451 static_count++; 3452 static_len += l; 3453 IPFW_WUNLOCK(chain); 3454 DEB(printf("ipfw: installed rule %d, static count now %d\n", 3455 rule->rulenum, static_count);) 3456 return (0); 3457 } 3458 3459 /** 3460 * Remove a static rule (including derived * dynamic rules) 3461 * and place it on the ``reap list'' for later reclamation. 3462 * The caller is in charge of clearing rule pointers to avoid 3463 * dangling pointers. 3464 * @return a pointer to the next entry. 3465 * Arguments are not checked, so they better be correct. 3466 */ 3467 static struct ip_fw * 3468 remove_rule(struct ip_fw_chain *chain, struct ip_fw *rule, struct ip_fw *prev) 3469 { 3470 struct ip_fw *n; 3471 int l = RULESIZE(rule); 3472 3473 IPFW_WLOCK_ASSERT(chain); 3474 3475 n = rule->next; 3476 IPFW_DYN_LOCK(); 3477 remove_dyn_rule(rule, NULL /* force removal */); 3478 IPFW_DYN_UNLOCK(); 3479 if (prev == NULL) 3480 chain->rules = n; 3481 else 3482 prev->next = n; 3483 static_count--; 3484 static_len -= l; 3485 3486 rule->next = chain->reap; 3487 chain->reap = rule; 3488 3489 return n; 3490 } 3491 3492 /** 3493 * Reclaim storage associated with a list of rules. This is 3494 * typically the list created using remove_rule. 3495 */ 3496 static void 3497 reap_rules(struct ip_fw *head) 3498 { 3499 struct ip_fw *rule; 3500 3501 while ((rule = head) != NULL) { 3502 head = head->next; 3503 if (DUMMYNET_LOADED) 3504 ip_dn_ruledel_ptr(rule); 3505 free(rule, M_IPFW); 3506 } 3507 } 3508 3509 /* 3510 * Remove all rules from a chain (except rules in set RESVD_SET 3511 * unless kill_default = 1). The caller is responsible for 3512 * reclaiming storage for the rules left in chain->reap. 3513 */ 3514 static void 3515 free_chain(struct ip_fw_chain *chain, int kill_default) 3516 { 3517 struct ip_fw *prev, *rule; 3518 3519 IPFW_WLOCK_ASSERT(chain); 3520 3521 flush_rule_ptrs(chain); /* more efficient to do outside the loop */ 3522 for (prev = NULL, rule = chain->rules; rule ; ) 3523 if (kill_default || rule->set != RESVD_SET) 3524 rule = remove_rule(chain, rule, prev); 3525 else { 3526 prev = rule; 3527 rule = rule->next; 3528 } 3529 } 3530 3531 /** 3532 * Remove all rules with given number, and also do set manipulation. 3533 * Assumes chain != NULL && *chain != NULL. 3534 * 3535 * The argument is an u_int32_t. The low 16 bit are the rule or set number, 3536 * the next 8 bits are the new set, the top 8 bits are the command: 3537 * 3538 * 0 delete rules with given number 3539 * 1 delete rules with given set number 3540 * 2 move rules with given number to new set 3541 * 3 move rules with given set number to new set 3542 * 4 swap sets with given numbers 3543 */ 3544 static int 3545 del_entry(struct ip_fw_chain *chain, u_int32_t arg) 3546 { 3547 struct ip_fw *prev = NULL, *rule; 3548 u_int16_t rulenum; /* rule or old_set */ 3549 u_int8_t cmd, new_set; 3550 3551 rulenum = arg & 0xffff; 3552 cmd = (arg >> 24) & 0xff; 3553 new_set = (arg >> 16) & 0xff; 3554 3555 if (cmd > 4) 3556 return EINVAL; 3557 if (new_set > RESVD_SET) 3558 return EINVAL; 3559 if (cmd == 0 || cmd == 2) { 3560 if (rulenum >= IPFW_DEFAULT_RULE) 3561 return EINVAL; 3562 } else { 3563 if (rulenum > RESVD_SET) /* old_set */ 3564 return EINVAL; 3565 } 3566 3567 IPFW_WLOCK(chain); 3568 rule = chain->rules; 3569 chain->reap = NULL; 3570 switch (cmd) { 3571 case 0: /* delete rules with given number */ 3572 /* 3573 * locate first rule to delete 3574 */ 3575 for (; rule->rulenum < rulenum; prev = rule, rule = rule->next) 3576 ; 3577 if (rule->rulenum != rulenum) { 3578 IPFW_WUNLOCK(chain); 3579 return EINVAL; 3580 } 3581 3582 /* 3583 * flush pointers outside the loop, then delete all matching 3584 * rules. prev remains the same throughout the cycle. 3585 */ 3586 flush_rule_ptrs(chain); 3587 while (rule->rulenum == rulenum) 3588 rule = remove_rule(chain, rule, prev); 3589 break; 3590 3591 case 1: /* delete all rules with given set number */ 3592 flush_rule_ptrs(chain); 3593 rule = chain->rules; 3594 while (rule->rulenum < IPFW_DEFAULT_RULE) 3595 if (rule->set == rulenum) 3596 rule = remove_rule(chain, rule, prev); 3597 else { 3598 prev = rule; 3599 rule = rule->next; 3600 } 3601 break; 3602 3603 case 2: /* move rules with given number to new set */ 3604 rule = chain->rules; 3605 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 3606 if (rule->rulenum == rulenum) 3607 rule->set = new_set; 3608 break; 3609 3610 case 3: /* move rules with given set number to new set */ 3611 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 3612 if (rule->set == rulenum) 3613 rule->set = new_set; 3614 break; 3615 3616 case 4: /* swap two sets */ 3617 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 3618 if (rule->set == rulenum) 3619 rule->set = new_set; 3620 else if (rule->set == new_set) 3621 rule->set = rulenum; 3622 break; 3623 } 3624 /* 3625 * Look for rules to reclaim. We grab the list before 3626 * releasing the lock then reclaim them w/o the lock to 3627 * avoid a LOR with dummynet. 3628 */ 3629 rule = chain->reap; 3630 chain->reap = NULL; 3631 IPFW_WUNLOCK(chain); 3632 if (rule) 3633 reap_rules(rule); 3634 return 0; 3635 } 3636 3637 /* 3638 * Clear counters for a specific rule. 3639 * The enclosing "table" is assumed locked. 3640 */ 3641 static void 3642 clear_counters(struct ip_fw *rule, int log_only) 3643 { 3644 ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule); 3645 3646 if (log_only == 0) { 3647 rule->bcnt = rule->pcnt = 0; 3648 rule->timestamp = 0; 3649 } 3650 if (l->o.opcode == O_LOG) 3651 l->log_left = l->max_log; 3652 } 3653 3654 /** 3655 * Reset some or all counters on firewall rules. 3656 * @arg frwl is null to clear all entries, or contains a specific 3657 * rule number. 3658 * @arg log_only is 1 if we only want to reset logs, zero otherwise. 3659 */ 3660 static int 3661 zero_entry(struct ip_fw_chain *chain, int rulenum, int log_only) 3662 { 3663 struct ip_fw *rule; 3664 char *msg; 3665 3666 IPFW_WLOCK(chain); 3667 if (rulenum == 0) { 3668 norule_counter = 0; 3669 for (rule = chain->rules; rule; rule = rule->next) 3670 clear_counters(rule, log_only); 3671 msg = log_only ? "ipfw: All logging counts reset.\n" : 3672 "ipfw: Accounting cleared.\n"; 3673 } else { 3674 int cleared = 0; 3675 /* 3676 * We can have multiple rules with the same number, so we 3677 * need to clear them all. 3678 */ 3679 for (rule = chain->rules; rule; rule = rule->next) 3680 if (rule->rulenum == rulenum) { 3681 while (rule && rule->rulenum == rulenum) { 3682 clear_counters(rule, log_only); 3683 rule = rule->next; 3684 } 3685 cleared = 1; 3686 break; 3687 } 3688 if (!cleared) { /* we did not find any matching rules */ 3689 IPFW_WUNLOCK(chain); 3690 return (EINVAL); 3691 } 3692 msg = log_only ? "ipfw: Entry %d logging count reset.\n" : 3693 "ipfw: Entry %d cleared.\n"; 3694 } 3695 IPFW_WUNLOCK(chain); 3696 3697 if (fw_verbose) 3698 log(LOG_SECURITY | LOG_NOTICE, msg, rulenum); 3699 return (0); 3700 } 3701 3702 /* 3703 * Check validity of the structure before insert. 3704 * Fortunately rules are simple, so this mostly need to check rule sizes. 3705 */ 3706 static int 3707 check_ipfw_struct(struct ip_fw *rule, int size) 3708 { 3709 int l, cmdlen = 0; 3710 int have_action=0; 3711 ipfw_insn *cmd; 3712 3713 if (size < sizeof(*rule)) { 3714 printf("ipfw: rule too short\n"); 3715 return (EINVAL); 3716 } 3717 /* first, check for valid size */ 3718 l = RULESIZE(rule); 3719 if (l != size) { 3720 printf("ipfw: size mismatch (have %d want %d)\n", size, l); 3721 return (EINVAL); 3722 } 3723 if (rule->act_ofs >= rule->cmd_len) { 3724 printf("ipfw: bogus action offset (%u > %u)\n", 3725 rule->act_ofs, rule->cmd_len - 1); 3726 return (EINVAL); 3727 } 3728 /* 3729 * Now go for the individual checks. Very simple ones, basically only 3730 * instruction sizes. 3731 */ 3732 for (l = rule->cmd_len, cmd = rule->cmd ; 3733 l > 0 ; l -= cmdlen, cmd += cmdlen) { 3734 cmdlen = F_LEN(cmd); 3735 if (cmdlen > l) { 3736 printf("ipfw: opcode %d size truncated\n", 3737 cmd->opcode); 3738 return EINVAL; 3739 } 3740 DEB(printf("ipfw: opcode %d\n", cmd->opcode);) 3741 switch (cmd->opcode) { 3742 case O_PROBE_STATE: 3743 case O_KEEP_STATE: 3744 case O_PROTO: 3745 case O_IP_SRC_ME: 3746 case O_IP_DST_ME: 3747 case O_LAYER2: 3748 case O_IN: 3749 case O_FRAG: 3750 case O_DIVERTED: 3751 case O_IPOPT: 3752 case O_IPTOS: 3753 case O_IPPRECEDENCE: 3754 case O_IPVER: 3755 case O_TCPWIN: 3756 case O_TCPFLAGS: 3757 case O_TCPOPTS: 3758 case O_ESTAB: 3759 case O_VERREVPATH: 3760 case O_VERSRCREACH: 3761 case O_ANTISPOOF: 3762 case O_IPSEC: 3763 #ifdef INET6 3764 case O_IP6_SRC_ME: 3765 case O_IP6_DST_ME: 3766 case O_EXT_HDR: 3767 case O_IP6: 3768 #endif 3769 case O_IP4: 3770 case O_TAG: 3771 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 3772 goto bad_size; 3773 break; 3774 3775 case O_UID: 3776 case O_GID: 3777 case O_JAIL: 3778 case O_IP_SRC: 3779 case O_IP_DST: 3780 case O_TCPSEQ: 3781 case O_TCPACK: 3782 case O_PROB: 3783 case O_ICMPTYPE: 3784 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 3785 goto bad_size; 3786 break; 3787 3788 case O_LIMIT: 3789 if (cmdlen != F_INSN_SIZE(ipfw_insn_limit)) 3790 goto bad_size; 3791 break; 3792 3793 case O_LOG: 3794 if (cmdlen != F_INSN_SIZE(ipfw_insn_log)) 3795 goto bad_size; 3796 3797 ((ipfw_insn_log *)cmd)->log_left = 3798 ((ipfw_insn_log *)cmd)->max_log; 3799 3800 break; 3801 3802 case O_IP_SRC_MASK: 3803 case O_IP_DST_MASK: 3804 /* only odd command lengths */ 3805 if ( !(cmdlen & 1) || cmdlen > 31) 3806 goto bad_size; 3807 break; 3808 3809 case O_IP_SRC_SET: 3810 case O_IP_DST_SET: 3811 if (cmd->arg1 == 0 || cmd->arg1 > 256) { 3812 printf("ipfw: invalid set size %d\n", 3813 cmd->arg1); 3814 return EINVAL; 3815 } 3816 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 3817 (cmd->arg1+31)/32 ) 3818 goto bad_size; 3819 break; 3820 3821 case O_IP_SRC_LOOKUP: 3822 case O_IP_DST_LOOKUP: 3823 if (cmd->arg1 >= IPFW_TABLES_MAX) { 3824 printf("ipfw: invalid table number %d\n", 3825 cmd->arg1); 3826 return (EINVAL); 3827 } 3828 if (cmdlen != F_INSN_SIZE(ipfw_insn) && 3829 cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 3830 goto bad_size; 3831 break; 3832 3833 case O_MACADDR2: 3834 if (cmdlen != F_INSN_SIZE(ipfw_insn_mac)) 3835 goto bad_size; 3836 break; 3837 3838 case O_NOP: 3839 case O_IPID: 3840 case O_IPTTL: 3841 case O_IPLEN: 3842 case O_TCPDATALEN: 3843 case O_TAGGED: 3844 if (cmdlen < 1 || cmdlen > 31) 3845 goto bad_size; 3846 break; 3847 3848 case O_MAC_TYPE: 3849 case O_IP_SRCPORT: 3850 case O_IP_DSTPORT: /* XXX artificial limit, 30 port pairs */ 3851 if (cmdlen < 2 || cmdlen > 31) 3852 goto bad_size; 3853 break; 3854 3855 case O_RECV: 3856 case O_XMIT: 3857 case O_VIA: 3858 if (cmdlen != F_INSN_SIZE(ipfw_insn_if)) 3859 goto bad_size; 3860 break; 3861 3862 case O_ALTQ: 3863 if (cmdlen != F_INSN_SIZE(ipfw_insn_altq)) 3864 goto bad_size; 3865 break; 3866 3867 case O_PIPE: 3868 case O_QUEUE: 3869 if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe)) 3870 goto bad_size; 3871 goto check_action; 3872 3873 case O_FORWARD_IP: 3874 #ifdef IPFIREWALL_FORWARD 3875 if (cmdlen != F_INSN_SIZE(ipfw_insn_sa)) 3876 goto bad_size; 3877 goto check_action; 3878 #else 3879 return EINVAL; 3880 #endif 3881 3882 case O_DIVERT: 3883 case O_TEE: 3884 if (ip_divert_ptr == NULL) 3885 return EINVAL; 3886 else 3887 goto check_size; 3888 case O_NETGRAPH: 3889 case O_NGTEE: 3890 if (!NG_IPFW_LOADED) 3891 return EINVAL; 3892 else 3893 goto check_size; 3894 case O_FORWARD_MAC: /* XXX not implemented yet */ 3895 case O_CHECK_STATE: 3896 case O_COUNT: 3897 case O_ACCEPT: 3898 case O_DENY: 3899 case O_REJECT: 3900 #ifdef INET6 3901 case O_UNREACH6: 3902 #endif 3903 case O_SKIPTO: 3904 check_size: 3905 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 3906 goto bad_size; 3907 check_action: 3908 if (have_action) { 3909 printf("ipfw: opcode %d, multiple actions" 3910 " not allowed\n", 3911 cmd->opcode); 3912 return EINVAL; 3913 } 3914 have_action = 1; 3915 if (l != cmdlen) { 3916 printf("ipfw: opcode %d, action must be" 3917 " last opcode\n", 3918 cmd->opcode); 3919 return EINVAL; 3920 } 3921 break; 3922 #ifdef INET6 3923 case O_IP6_SRC: 3924 case O_IP6_DST: 3925 if (cmdlen != F_INSN_SIZE(struct in6_addr) + 3926 F_INSN_SIZE(ipfw_insn)) 3927 goto bad_size; 3928 break; 3929 3930 case O_FLOW6ID: 3931 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 3932 ((ipfw_insn_u32 *)cmd)->o.arg1) 3933 goto bad_size; 3934 break; 3935 3936 case O_IP6_SRC_MASK: 3937 case O_IP6_DST_MASK: 3938 if ( !(cmdlen & 1) || cmdlen > 127) 3939 goto bad_size; 3940 break; 3941 case O_ICMP6TYPE: 3942 if( cmdlen != F_INSN_SIZE( ipfw_insn_icmp6 ) ) 3943 goto bad_size; 3944 break; 3945 #endif 3946 3947 default: 3948 switch (cmd->opcode) { 3949 #ifndef INET6 3950 case O_IP6_SRC_ME: 3951 case O_IP6_DST_ME: 3952 case O_EXT_HDR: 3953 case O_IP6: 3954 case O_UNREACH6: 3955 case O_IP6_SRC: 3956 case O_IP6_DST: 3957 case O_FLOW6ID: 3958 case O_IP6_SRC_MASK: 3959 case O_IP6_DST_MASK: 3960 case O_ICMP6TYPE: 3961 printf("ipfw: no IPv6 support in kernel\n"); 3962 return EPROTONOSUPPORT; 3963 #endif 3964 default: 3965 printf("ipfw: opcode %d, unknown opcode\n", 3966 cmd->opcode); 3967 return EINVAL; 3968 } 3969 } 3970 } 3971 if (have_action == 0) { 3972 printf("ipfw: missing action\n"); 3973 return EINVAL; 3974 } 3975 return 0; 3976 3977 bad_size: 3978 printf("ipfw: opcode %d size %d wrong\n", 3979 cmd->opcode, cmdlen); 3980 return EINVAL; 3981 } 3982 3983 /* 3984 * Copy the static and dynamic rules to the supplied buffer 3985 * and return the amount of space actually used. 3986 */ 3987 static size_t 3988 ipfw_getrules(struct ip_fw_chain *chain, void *buf, size_t space) 3989 { 3990 char *bp = buf; 3991 char *ep = bp + space; 3992 struct ip_fw *rule; 3993 int i; 3994 time_t boot_seconds; 3995 3996 boot_seconds = boottime.tv_sec; 3997 /* XXX this can take a long time and locking will block packet flow */ 3998 IPFW_RLOCK(chain); 3999 for (rule = chain->rules; rule ; rule = rule->next) { 4000 /* 4001 * Verify the entry fits in the buffer in case the 4002 * rules changed between calculating buffer space and 4003 * now. This would be better done using a generation 4004 * number but should suffice for now. 4005 */ 4006 i = RULESIZE(rule); 4007 if (bp + i <= ep) { 4008 bcopy(rule, bp, i); 4009 /* 4010 * XXX HACK. Store the disable mask in the "next" pointer 4011 * in a wild attempt to keep the ABI the same. 4012 * Why do we do this on EVERY rule? 4013 */ 4014 bcopy(&set_disable, &(((struct ip_fw *)bp)->next_rule), 4015 sizeof(set_disable)); 4016 if (((struct ip_fw *)bp)->timestamp) 4017 ((struct ip_fw *)bp)->timestamp += boot_seconds; 4018 bp += i; 4019 } 4020 } 4021 IPFW_RUNLOCK(chain); 4022 if (ipfw_dyn_v) { 4023 ipfw_dyn_rule *p, *last = NULL; 4024 4025 IPFW_DYN_LOCK(); 4026 for (i = 0 ; i < curr_dyn_buckets; i++) 4027 for (p = ipfw_dyn_v[i] ; p != NULL; p = p->next) { 4028 if (bp + sizeof *p <= ep) { 4029 ipfw_dyn_rule *dst = 4030 (ipfw_dyn_rule *)bp; 4031 bcopy(p, dst, sizeof *p); 4032 bcopy(&(p->rule->rulenum), &(dst->rule), 4033 sizeof(p->rule->rulenum)); 4034 /* 4035 * store a non-null value in "next". 4036 * The userland code will interpret a 4037 * NULL here as a marker 4038 * for the last dynamic rule. 4039 */ 4040 bcopy(&dst, &dst->next, sizeof(dst)); 4041 last = dst; 4042 dst->expire = 4043 TIME_LEQ(dst->expire, time_uptime) ? 4044 0 : dst->expire - time_uptime ; 4045 bp += sizeof(ipfw_dyn_rule); 4046 } 4047 } 4048 IPFW_DYN_UNLOCK(); 4049 if (last != NULL) /* mark last dynamic rule */ 4050 bzero(&last->next, sizeof(last)); 4051 } 4052 return (bp - (char *)buf); 4053 } 4054 4055 4056 /** 4057 * {set|get}sockopt parser. 4058 */ 4059 static int 4060 ipfw_ctl(struct sockopt *sopt) 4061 { 4062 #define RULE_MAXSIZE (256*sizeof(u_int32_t)) 4063 int error, rule_num; 4064 size_t size; 4065 struct ip_fw *buf, *rule; 4066 u_int32_t rulenum[2]; 4067 4068 error = suser(sopt->sopt_td); 4069 if (error) 4070 return (error); 4071 4072 /* 4073 * Disallow modifications in really-really secure mode, but still allow 4074 * the logging counters to be reset. 4075 */ 4076 if (sopt->sopt_name == IP_FW_ADD || 4077 (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) { 4078 error = securelevel_ge(sopt->sopt_td->td_ucred, 3); 4079 if (error) 4080 return (error); 4081 } 4082 4083 error = 0; 4084 4085 switch (sopt->sopt_name) { 4086 case IP_FW_GET: 4087 /* 4088 * pass up a copy of the current rules. Static rules 4089 * come first (the last of which has number IPFW_DEFAULT_RULE), 4090 * followed by a possibly empty list of dynamic rule. 4091 * The last dynamic rule has NULL in the "next" field. 4092 * 4093 * Note that the calculated size is used to bound the 4094 * amount of data returned to the user. The rule set may 4095 * change between calculating the size and returning the 4096 * data in which case we'll just return what fits. 4097 */ 4098 size = static_len; /* size of static rules */ 4099 if (ipfw_dyn_v) /* add size of dyn.rules */ 4100 size += (dyn_count * sizeof(ipfw_dyn_rule)); 4101 4102 /* 4103 * XXX todo: if the user passes a short length just to know 4104 * how much room is needed, do not bother filling up the 4105 * buffer, just jump to the sooptcopyout. 4106 */ 4107 buf = malloc(size, M_TEMP, M_WAITOK); 4108 error = sooptcopyout(sopt, buf, 4109 ipfw_getrules(&layer3_chain, buf, size)); 4110 free(buf, M_TEMP); 4111 break; 4112 4113 case IP_FW_FLUSH: 4114 /* 4115 * Normally we cannot release the lock on each iteration. 4116 * We could do it here only because we start from the head all 4117 * the times so there is no risk of missing some entries. 4118 * On the other hand, the risk is that we end up with 4119 * a very inconsistent ruleset, so better keep the lock 4120 * around the whole cycle. 4121 * 4122 * XXX this code can be improved by resetting the head of 4123 * the list to point to the default rule, and then freeing 4124 * the old list without the need for a lock. 4125 */ 4126 4127 IPFW_WLOCK(&layer3_chain); 4128 layer3_chain.reap = NULL; 4129 free_chain(&layer3_chain, 0 /* keep default rule */); 4130 rule = layer3_chain.reap; 4131 layer3_chain.reap = NULL; 4132 IPFW_WUNLOCK(&layer3_chain); 4133 if (rule != NULL) 4134 reap_rules(rule); 4135 break; 4136 4137 case IP_FW_ADD: 4138 rule = malloc(RULE_MAXSIZE, M_TEMP, M_WAITOK); 4139 error = sooptcopyin(sopt, rule, RULE_MAXSIZE, 4140 sizeof(struct ip_fw) ); 4141 if (error == 0) 4142 error = check_ipfw_struct(rule, sopt->sopt_valsize); 4143 if (error == 0) { 4144 error = add_rule(&layer3_chain, rule); 4145 size = RULESIZE(rule); 4146 if (!error && sopt->sopt_dir == SOPT_GET) 4147 error = sooptcopyout(sopt, rule, size); 4148 } 4149 free(rule, M_TEMP); 4150 break; 4151 4152 case IP_FW_DEL: 4153 /* 4154 * IP_FW_DEL is used for deleting single rules or sets, 4155 * and (ab)used to atomically manipulate sets. Argument size 4156 * is used to distinguish between the two: 4157 * sizeof(u_int32_t) 4158 * delete single rule or set of rules, 4159 * or reassign rules (or sets) to a different set. 4160 * 2*sizeof(u_int32_t) 4161 * atomic disable/enable sets. 4162 * first u_int32_t contains sets to be disabled, 4163 * second u_int32_t contains sets to be enabled. 4164 */ 4165 error = sooptcopyin(sopt, rulenum, 4166 2*sizeof(u_int32_t), sizeof(u_int32_t)); 4167 if (error) 4168 break; 4169 size = sopt->sopt_valsize; 4170 if (size == sizeof(u_int32_t)) /* delete or reassign */ 4171 error = del_entry(&layer3_chain, rulenum[0]); 4172 else if (size == 2*sizeof(u_int32_t)) /* set enable/disable */ 4173 set_disable = 4174 (set_disable | rulenum[0]) & ~rulenum[1] & 4175 ~(1<<RESVD_SET); /* set RESVD_SET always enabled */ 4176 else 4177 error = EINVAL; 4178 break; 4179 4180 case IP_FW_ZERO: 4181 case IP_FW_RESETLOG: /* argument is an int, the rule number */ 4182 rule_num = 0; 4183 if (sopt->sopt_val != 0) { 4184 error = sooptcopyin(sopt, &rule_num, 4185 sizeof(int), sizeof(int)); 4186 if (error) 4187 break; 4188 } 4189 error = zero_entry(&layer3_chain, rule_num, 4190 sopt->sopt_name == IP_FW_RESETLOG); 4191 break; 4192 4193 case IP_FW_TABLE_ADD: 4194 { 4195 ipfw_table_entry ent; 4196 4197 error = sooptcopyin(sopt, &ent, 4198 sizeof(ent), sizeof(ent)); 4199 if (error) 4200 break; 4201 error = add_table_entry(&layer3_chain, ent.tbl, 4202 ent.addr, ent.masklen, ent.value); 4203 } 4204 break; 4205 4206 case IP_FW_TABLE_DEL: 4207 { 4208 ipfw_table_entry ent; 4209 4210 error = sooptcopyin(sopt, &ent, 4211 sizeof(ent), sizeof(ent)); 4212 if (error) 4213 break; 4214 error = del_table_entry(&layer3_chain, ent.tbl, 4215 ent.addr, ent.masklen); 4216 } 4217 break; 4218 4219 case IP_FW_TABLE_FLUSH: 4220 { 4221 u_int16_t tbl; 4222 4223 error = sooptcopyin(sopt, &tbl, 4224 sizeof(tbl), sizeof(tbl)); 4225 if (error) 4226 break; 4227 IPFW_WLOCK(&layer3_chain); 4228 error = flush_table(&layer3_chain, tbl); 4229 IPFW_WUNLOCK(&layer3_chain); 4230 } 4231 break; 4232 4233 case IP_FW_TABLE_GETSIZE: 4234 { 4235 u_int32_t tbl, cnt; 4236 4237 if ((error = sooptcopyin(sopt, &tbl, sizeof(tbl), 4238 sizeof(tbl)))) 4239 break; 4240 IPFW_RLOCK(&layer3_chain); 4241 error = count_table(&layer3_chain, tbl, &cnt); 4242 IPFW_RUNLOCK(&layer3_chain); 4243 if (error) 4244 break; 4245 error = sooptcopyout(sopt, &cnt, sizeof(cnt)); 4246 } 4247 break; 4248 4249 case IP_FW_TABLE_LIST: 4250 { 4251 ipfw_table *tbl; 4252 4253 if (sopt->sopt_valsize < sizeof(*tbl)) { 4254 error = EINVAL; 4255 break; 4256 } 4257 size = sopt->sopt_valsize; 4258 tbl = malloc(size, M_TEMP, M_WAITOK); 4259 error = sooptcopyin(sopt, tbl, size, sizeof(*tbl)); 4260 if (error) { 4261 free(tbl, M_TEMP); 4262 break; 4263 } 4264 tbl->size = (size - sizeof(*tbl)) / 4265 sizeof(ipfw_table_entry); 4266 IPFW_RLOCK(&layer3_chain); 4267 error = dump_table(&layer3_chain, tbl); 4268 IPFW_RUNLOCK(&layer3_chain); 4269 if (error) { 4270 free(tbl, M_TEMP); 4271 break; 4272 } 4273 error = sooptcopyout(sopt, tbl, size); 4274 free(tbl, M_TEMP); 4275 } 4276 break; 4277 4278 default: 4279 printf("ipfw: ipfw_ctl invalid option %d\n", sopt->sopt_name); 4280 error = EINVAL; 4281 } 4282 4283 return (error); 4284 #undef RULE_MAXSIZE 4285 } 4286 4287 /** 4288 * dummynet needs a reference to the default rule, because rules can be 4289 * deleted while packets hold a reference to them. When this happens, 4290 * dummynet changes the reference to the default rule (it could well be a 4291 * NULL pointer, but this way we do not need to check for the special 4292 * case, plus here he have info on the default behaviour). 4293 */ 4294 struct ip_fw *ip_fw_default_rule; 4295 4296 /* 4297 * This procedure is only used to handle keepalives. It is invoked 4298 * every dyn_keepalive_period 4299 */ 4300 static void 4301 ipfw_tick(void * __unused unused) 4302 { 4303 struct mbuf *m0, *m, *mnext, **mtailp; 4304 int i; 4305 ipfw_dyn_rule *q; 4306 4307 if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0) 4308 goto done; 4309 4310 /* 4311 * We make a chain of packets to go out here -- not deferring 4312 * until after we drop the IPFW dynamic rule lock would result 4313 * in a lock order reversal with the normal packet input -> ipfw 4314 * call stack. 4315 */ 4316 m0 = NULL; 4317 mtailp = &m0; 4318 IPFW_DYN_LOCK(); 4319 for (i = 0 ; i < curr_dyn_buckets ; i++) { 4320 for (q = ipfw_dyn_v[i] ; q ; q = q->next ) { 4321 if (q->dyn_type == O_LIMIT_PARENT) 4322 continue; 4323 if (q->id.proto != IPPROTO_TCP) 4324 continue; 4325 if ( (q->state & BOTH_SYN) != BOTH_SYN) 4326 continue; 4327 if (TIME_LEQ( time_uptime+dyn_keepalive_interval, 4328 q->expire)) 4329 continue; /* too early */ 4330 if (TIME_LEQ(q->expire, time_uptime)) 4331 continue; /* too late, rule expired */ 4332 4333 *mtailp = send_pkt(NULL, &(q->id), q->ack_rev - 1, 4334 q->ack_fwd, TH_SYN); 4335 if (*mtailp != NULL) 4336 mtailp = &(*mtailp)->m_nextpkt; 4337 *mtailp = send_pkt(NULL, &(q->id), q->ack_fwd - 1, 4338 q->ack_rev, 0); 4339 if (*mtailp != NULL) 4340 mtailp = &(*mtailp)->m_nextpkt; 4341 } 4342 } 4343 IPFW_DYN_UNLOCK(); 4344 for (m = mnext = m0; m != NULL; m = mnext) { 4345 mnext = m->m_nextpkt; 4346 m->m_nextpkt = NULL; 4347 ip_output(m, NULL, NULL, 0, NULL, NULL); 4348 } 4349 done: 4350 callout_reset(&ipfw_timeout, dyn_keepalive_period*hz, ipfw_tick, NULL); 4351 } 4352 4353 int 4354 ipfw_init(void) 4355 { 4356 struct ip_fw default_rule; 4357 int error; 4358 4359 #ifdef INET6 4360 /* Setup IPv6 fw sysctl tree. */ 4361 sysctl_ctx_init(&ip6_fw_sysctl_ctx); 4362 ip6_fw_sysctl_tree = SYSCTL_ADD_NODE(&ip6_fw_sysctl_ctx, 4363 SYSCTL_STATIC_CHILDREN(_net_inet6_ip6), OID_AUTO, "fw", 4364 CTLFLAG_RW | CTLFLAG_SECURE, 0, "Firewall"); 4365 SYSCTL_ADD_INT(&ip6_fw_sysctl_ctx, SYSCTL_CHILDREN(ip6_fw_sysctl_tree), 4366 OID_AUTO, "deny_unknown_exthdrs", CTLFLAG_RW | CTLFLAG_SECURE, 4367 &fw_deny_unknown_exthdrs, 0, 4368 "Deny packets with unknown IPv6 Extension Headers"); 4369 #endif 4370 4371 layer3_chain.rules = NULL; 4372 layer3_chain.want_write = 0; 4373 layer3_chain.busy_count = 0; 4374 cv_init(&layer3_chain.cv, "Condition variable for IPFW rw locks"); 4375 IPFW_LOCK_INIT(&layer3_chain); 4376 ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 4377 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 4378 UMA_ALIGN_PTR, 0); 4379 IPFW_DYN_LOCK_INIT(); 4380 callout_init(&ipfw_timeout, NET_CALLOUT_MPSAFE); 4381 4382 bzero(&default_rule, sizeof default_rule); 4383 4384 default_rule.act_ofs = 0; 4385 default_rule.rulenum = IPFW_DEFAULT_RULE; 4386 default_rule.cmd_len = 1; 4387 default_rule.set = RESVD_SET; 4388 4389 default_rule.cmd[0].len = 1; 4390 default_rule.cmd[0].opcode = 4391 #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 4392 1 ? O_ACCEPT : 4393 #endif 4394 O_DENY; 4395 4396 error = add_rule(&layer3_chain, &default_rule); 4397 if (error != 0) { 4398 printf("ipfw2: error %u initializing default rule " 4399 "(support disabled)\n", error); 4400 IPFW_DYN_LOCK_DESTROY(); 4401 IPFW_LOCK_DESTROY(&layer3_chain); 4402 uma_zdestroy(ipfw_dyn_rule_zone); 4403 return (error); 4404 } 4405 4406 ip_fw_default_rule = layer3_chain.rules; 4407 printf("ipfw2 " 4408 #ifdef INET6 4409 "(+ipv6) " 4410 #endif 4411 "initialized, divert %s, " 4412 "rule-based forwarding " 4413 #ifdef IPFIREWALL_FORWARD 4414 "enabled, " 4415 #else 4416 "disabled, " 4417 #endif 4418 "default to %s, logging ", 4419 #ifdef IPDIVERT 4420 "enabled", 4421 #else 4422 "loadable", 4423 #endif 4424 default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny"); 4425 4426 #ifdef IPFIREWALL_VERBOSE 4427 fw_verbose = 1; 4428 #endif 4429 #ifdef IPFIREWALL_VERBOSE_LIMIT 4430 verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 4431 #endif 4432 if (fw_verbose == 0) 4433 printf("disabled\n"); 4434 else if (verbose_limit == 0) 4435 printf("unlimited\n"); 4436 else 4437 printf("limited to %d packets/entry by default\n", 4438 verbose_limit); 4439 4440 error = init_tables(&layer3_chain); 4441 if (error) { 4442 IPFW_DYN_LOCK_DESTROY(); 4443 IPFW_LOCK_DESTROY(&layer3_chain); 4444 uma_zdestroy(ipfw_dyn_rule_zone); 4445 return (error); 4446 } 4447 ip_fw_ctl_ptr = ipfw_ctl; 4448 ip_fw_chk_ptr = ipfw_chk; 4449 callout_reset(&ipfw_timeout, hz, ipfw_tick, NULL); 4450 4451 return (0); 4452 } 4453 4454 void 4455 ipfw_destroy(void) 4456 { 4457 struct ip_fw *reap; 4458 4459 ip_fw_chk_ptr = NULL; 4460 ip_fw_ctl_ptr = NULL; 4461 callout_drain(&ipfw_timeout); 4462 IPFW_WLOCK(&layer3_chain); 4463 flush_tables(&layer3_chain); 4464 layer3_chain.reap = NULL; 4465 free_chain(&layer3_chain, 1 /* kill default rule */); 4466 reap = layer3_chain.reap, layer3_chain.reap = NULL; 4467 IPFW_WUNLOCK(&layer3_chain); 4468 if (reap != NULL) 4469 reap_rules(reap); 4470 IPFW_DYN_LOCK_DESTROY(); 4471 uma_zdestroy(ipfw_dyn_rule_zone); 4472 IPFW_LOCK_DESTROY(&layer3_chain); 4473 4474 #ifdef INET6 4475 /* Free IPv6 fw sysctl tree. */ 4476 sysctl_ctx_free(&ip6_fw_sysctl_ctx); 4477 #endif 4478 4479 printf("IP firewall unloaded\n"); 4480 }
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