ip_fw2.c revision 101628
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: head/sys/netinet/ip_fw2.c 101628 2002-08-10 04:37:32Z luigi $ 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_ipdn.h" 38#include "opt_ipdivert.h" 39#include "opt_inet.h" 40#ifndef INET 41#error IPFIREWALL requires INET. 42#endif /* INET */ 43#endif 44 45#define IPFW2 1 46#if IPFW2 47#include <sys/param.h> 48#include <sys/systm.h> 49#include <sys/malloc.h> 50#include <sys/mbuf.h> 51#include <sys/kernel.h> 52#include <sys/proc.h> 53#include <sys/socket.h> 54#include <sys/socketvar.h> 55#include <sys/sysctl.h> 56#include <sys/syslog.h> 57#include <sys/ucred.h> 58#include <net/if.h> 59#include <net/route.h> 60#include <netinet/in.h> 61#include <netinet/in_systm.h> 62#include <netinet/in_var.h> 63#include <netinet/in_pcb.h> 64#include <netinet/ip.h> 65#include <netinet/ip_var.h> 66#include <netinet/ip_icmp.h> 67#include <netinet/ip_fw.h> 68#include <netinet/ip_dummynet.h> 69#include <netinet/tcp.h> 70#include <netinet/tcp_timer.h> 71#include <netinet/tcp_var.h> 72#include <netinet/tcpip.h> 73#include <netinet/udp.h> 74#include <netinet/udp_var.h> 75 76#include <netinet/if_ether.h> /* XXX for ETHERTYPE_IP */ 77 78#include <machine/in_cksum.h> /* XXX for in_cksum */ 79 80/* 81 * set_disable contains one bit per set value (0..31). 82 * If the bit is set, all rules with the corresponding set 83 * are disabled. Set 31 is reserved for the default rule 84 * and CANNOT be disabled. 85 */ 86static u_int32_t set_disable; 87 88static int fw_verbose; 89static int verbose_limit; 90 91static struct callout_handle ipfw_timeout_h; 92#define IPFW_DEFAULT_RULE 65535 93 94/* 95 * list of rules for layer 3 96 */ 97static struct ip_fw *layer3_chain; 98 99MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's"); 100 101static int fw_debug = 1; 102int fw_one_pass = 1; 103static int autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 104 105#ifdef SYSCTL_NODE 106SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 107SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW, 108 &fw_enable, 0, "Enable ipfw"); 109SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, CTLFLAG_RW, 110 &autoinc_step, 0, "Rule number autincrement step"); 111SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW, 112 &fw_one_pass, 0, 113 "Only do a single pass through ipfw when using dummynet(4)"); 114SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW, 115 &fw_debug, 0, "Enable printing of debug ip_fw statements"); 116SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW, 117 &fw_verbose, 0, "Log matches to ipfw rules"); 118SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, 119 &verbose_limit, 0, "Set upper limit of matches of ipfw rules logged"); 120 121/* 122 * Description of dynamic rules. 123 * 124 * Dynamic rules are stored in lists accessed through a hash table 125 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 126 * be modified through the sysctl variable dyn_buckets which is 127 * updated when the table becomes empty. 128 * 129 * XXX currently there is only one list, ipfw_dyn. 130 * 131 * When a packet is received, its address fields are first masked 132 * with the mask defined for the rule, then hashed, then matched 133 * against the entries in the corresponding list. 134 * Dynamic rules can be used for different purposes: 135 * + stateful rules; 136 * + enforcing limits on the number of sessions; 137 * + in-kernel NAT (not implemented yet) 138 * 139 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 140 * measured in seconds and depending on the flags. 141 * 142 * The total number of dynamic rules is stored in dyn_count. 143 * The max number of dynamic rules is dyn_max. When we reach 144 * the maximum number of rules we do not create anymore. This is 145 * done to avoid consuming too much memory, but also too much 146 * time when searching on each packet (ideally, we should try instead 147 * to put a limit on the length of the list on each bucket...). 148 * 149 * Each dynamic rule holds a pointer to the parent ipfw rule so 150 * we know what action to perform. Dynamic rules are removed when 151 * the parent rule is deleted. XXX we should make them survive. 152 * 153 * There are some limitations with dynamic rules -- we do not 154 * obey the 'randomized match', and we do not do multiple 155 * passes through the firewall. XXX check the latter!!! 156 */ 157static ipfw_dyn_rule **ipfw_dyn_v = NULL; 158static u_int32_t dyn_buckets = 256; /* must be power of 2 */ 159static u_int32_t curr_dyn_buckets = 256; /* must be power of 2 */ 160 161/* 162 * Timeouts for various events in handing dynamic rules. 163 */ 164static u_int32_t dyn_ack_lifetime = 300; 165static u_int32_t dyn_syn_lifetime = 20; 166static u_int32_t dyn_fin_lifetime = 1; 167static u_int32_t dyn_rst_lifetime = 1; 168static u_int32_t dyn_udp_lifetime = 10; 169static u_int32_t dyn_short_lifetime = 5; 170 171static u_int32_t dyn_keepalive = 1; /* do send keepalives */ 172 173static u_int32_t static_count; /* # of static rules */ 174static u_int32_t static_len; /* size in bytes of static rules */ 175static u_int32_t dyn_count; /* # of dynamic rules */ 176static u_int32_t dyn_max = 1000; /* max # of dynamic rules */ 177 178SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW, 179 &dyn_buckets, 0, "Number of dyn. buckets"); 180SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD, 181 &curr_dyn_buckets, 0, "Current Number of dyn. buckets"); 182SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD, 183 &dyn_count, 0, "Number of dyn. rules"); 184SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW, 185 &dyn_max, 0, "Max number of dyn. rules"); 186SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD, 187 &static_count, 0, "Number of static rules"); 188SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW, 189 &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks"); 190SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW, 191 &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn"); 192SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW, 193 &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin"); 194SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW, 195 &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst"); 196SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW, 197 &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP"); 198SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW, 199 &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations"); 200SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, CTLFLAG_RW, 201 &dyn_keepalive, 0, "Enable keepalives for dyn. rules"); 202 203#endif /* SYSCTL_NODE */ 204 205 206static ip_fw_chk_t ipfw_chk; 207 208ip_dn_ruledel_t *ip_dn_ruledel_ptr = NULL; /* hook into dummynet */ 209 210/* 211 * This macro maps an ip pointer into a layer3 header pointer of type T 212 */ 213#define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 214 215static __inline int 216icmptype_match(struct ip *ip, ipfw_insn_u32 *cmd) 217{ 218 int type = L3HDR(struct icmp,ip)->icmp_type; 219 220 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 221} 222 223#define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 224 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 225 226static int 227is_icmp_query(struct ip *ip) 228{ 229 int type = L3HDR(struct icmp, ip)->icmp_type; 230 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 231} 232#undef TT 233 234/* 235 * The following checks use two arrays of 8 or 16 bits to store the 236 * bits that we want set or clear, respectively. They are in the 237 * low and high half of cmd->arg1 or cmd->d[0]. 238 * 239 * We scan options and store the bits we find set. We succeed if 240 * 241 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 242 * 243 * The code is sometimes optimized not to store additional variables. 244 */ 245 246static int 247flags_match(ipfw_insn *cmd, u_int8_t bits) 248{ 249 u_char want_clear; 250 bits = ~bits; 251 252 if ( ((cmd->arg1 & 0xff) & bits) != 0) 253 return 0; /* some bits we want set were clear */ 254 want_clear = (cmd->arg1 >> 8) & 0xff; 255 if ( (want_clear & bits) != want_clear) 256 return 0; /* some bits we want clear were set */ 257 return 1; 258} 259 260static int 261ipopts_match(struct ip *ip, ipfw_insn *cmd) 262{ 263 int optlen, bits = 0; 264 u_char *cp = (u_char *)(ip + 1); 265 int x = (ip->ip_hl << 2) - sizeof (struct ip); 266 267 for (; x > 0; x -= optlen, cp += optlen) { 268 int opt = cp[IPOPT_OPTVAL]; 269 270 if (opt == IPOPT_EOL) 271 break; 272 if (opt == IPOPT_NOP) 273 optlen = 1; 274 else { 275 optlen = cp[IPOPT_OLEN]; 276 if (optlen <= 0 || optlen > x) 277 return 0; /* invalid or truncated */ 278 } 279 switch (opt) { 280 281 default: 282 break; 283 284 case IPOPT_LSRR: 285 bits |= IP_FW_IPOPT_LSRR; 286 break; 287 288 case IPOPT_SSRR: 289 bits |= IP_FW_IPOPT_SSRR; 290 break; 291 292 case IPOPT_RR: 293 bits |= IP_FW_IPOPT_RR; 294 break; 295 296 case IPOPT_TS: 297 bits |= IP_FW_IPOPT_TS; 298 break; 299 } 300 } 301 return (flags_match(cmd, bits)); 302} 303 304static int 305tcpopts_match(struct ip *ip, ipfw_insn *cmd) 306{ 307 int optlen, bits = 0; 308 struct tcphdr *tcp = L3HDR(struct tcphdr,ip); 309 u_char *cp = (u_char *)(tcp + 1); 310 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 311 312 for (; x > 0; x -= optlen, cp += optlen) { 313 int opt = cp[0]; 314 if (opt == TCPOPT_EOL) 315 break; 316 if (opt == TCPOPT_NOP) 317 optlen = 1; 318 else { 319 optlen = cp[1]; 320 if (optlen <= 0) 321 break; 322 } 323 324 switch (opt) { 325 326 default: 327 break; 328 329 case TCPOPT_MAXSEG: 330 bits |= IP_FW_TCPOPT_MSS; 331 break; 332 333 case TCPOPT_WINDOW: 334 bits |= IP_FW_TCPOPT_WINDOW; 335 break; 336 337 case TCPOPT_SACK_PERMITTED: 338 case TCPOPT_SACK: 339 bits |= IP_FW_TCPOPT_SACK; 340 break; 341 342 case TCPOPT_TIMESTAMP: 343 bits |= IP_FW_TCPOPT_TS; 344 break; 345 346 case TCPOPT_CC: 347 case TCPOPT_CCNEW: 348 case TCPOPT_CCECHO: 349 bits |= IP_FW_TCPOPT_CC; 350 break; 351 } 352 } 353 return (flags_match(cmd, bits)); 354} 355 356static int 357iface_match(struct ifnet *ifp, ipfw_insn_if *cmd) 358{ 359 if (ifp == NULL) /* no iface with this packet, match fails */ 360 return 0; 361 /* Check by name or by IP address */ 362 if (cmd->name[0] != '\0') { /* match by name */ 363 /* Check unit number (-1 is wildcard) */ 364 if (cmd->p.unit != -1 && cmd->p.unit != ifp->if_unit) 365 return(0); 366 /* Check name */ 367 if (!strncmp(ifp->if_name, cmd->name, IFNAMSIZ)) 368 return(1); 369 } else { 370 struct ifaddr *ia; 371 372 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 373 if (ia->ifa_addr == NULL) 374 continue; 375 if (ia->ifa_addr->sa_family != AF_INET) 376 continue; 377 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 378 (ia->ifa_addr))->sin_addr.s_addr) 379 return(1); /* match */ 380 } 381 } 382 return(0); /* no match, fail ... */ 383} 384 385static u_int64_t norule_counter; /* counter for ipfw_log(NULL...) */ 386 387#define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0 388#define SNP(buf) buf, sizeof(buf) 389 390/* 391 * We enter here when we have a rule with O_LOG. 392 * XXX this function alone takes about 2Kbytes of code! 393 */ 394static void 395ipfw_log(struct ip_fw *f, u_int hlen, struct ether_header *eh, 396 struct mbuf *m, struct ifnet *oif) 397{ 398 char *action; 399 int limit_reached = 0; 400 char action2[40], proto[48], fragment[28]; 401 402 fragment[0] = '\0'; 403 proto[0] = '\0'; 404 405 if (f == NULL) { /* bogus pkt */ 406 if (verbose_limit != 0 && norule_counter >= verbose_limit) 407 return; 408 norule_counter++; 409 if (norule_counter == verbose_limit) 410 limit_reached = verbose_limit; 411 action = "Refuse"; 412 } else { /* O_LOG is the first action, find the real one */ 413 ipfw_insn *cmd = ACTION_PTR(f); 414 ipfw_insn_log *l = (ipfw_insn_log *)cmd; 415 416 if (l->max_log != 0 && l->log_left == 0) 417 return; 418 l->log_left--; 419 if (l->log_left == 0) 420 limit_reached = l->max_log; 421 cmd += F_LEN(cmd); /* point to first action */ 422 if (cmd->opcode == O_PROB) 423 cmd += F_LEN(cmd); 424 425 action = action2; 426 switch (cmd->opcode) { 427 case O_DENY: 428 action = "Deny"; 429 break; 430 431 case O_REJECT: 432 if (cmd->arg1==ICMP_REJECT_RST) 433 action = "Reset"; 434 else if (cmd->arg1==ICMP_UNREACH_HOST) 435 action = "Reject"; 436 else 437 snprintf(SNPARGS(action2, 0), "Unreach %d", 438 cmd->arg1); 439 break; 440 441 case O_ACCEPT: 442 action = "Accept"; 443 break; 444 case O_COUNT: 445 action = "Count"; 446 break; 447 case O_DIVERT: 448 snprintf(SNPARGS(action2, 0), "Divert %d", 449 cmd->arg1); 450 break; 451 case O_TEE: 452 snprintf(SNPARGS(action2, 0), "Tee %d", 453 cmd->arg1); 454 break; 455 case O_SKIPTO: 456 snprintf(SNPARGS(action2, 0), "SkipTo %d", 457 cmd->arg1); 458 break; 459 case O_PIPE: 460 snprintf(SNPARGS(action2, 0), "Pipe %d", 461 cmd->arg1); 462 break; 463 case O_QUEUE: 464 snprintf(SNPARGS(action2, 0), "Queue %d", 465 cmd->arg1); 466 break; 467 case O_FORWARD_IP: { 468 ipfw_insn_sa *sa = (ipfw_insn_sa *)cmd; 469 int len; 470 471 len = snprintf(SNPARGS(action2, 0), "Forward to %s", 472 inet_ntoa(sa->sa.sin_addr)); 473 if (sa->sa.sin_port) 474 snprintf(SNPARGS(action2, len), ":%d", 475 ntohs(sa->sa.sin_port)); 476 } 477 break; 478 default: 479 action = "UNKNOWN"; 480 break; 481 } 482 } 483 484 if (hlen == 0) { /* non-ip */ 485 snprintf(SNPARGS(proto, 0), "MAC"); 486 } else { 487 struct ip *ip = mtod(m, struct ip *); 488 /* these three are all aliases to the same thing */ 489 struct icmp *const icmp = L3HDR(struct icmp, ip); 490 struct tcphdr *const tcp = (struct tcphdr *)icmp; 491 struct udphdr *const udp = (struct udphdr *)icmp; 492 493 int ip_off, offset, ip_len; 494 495 int len; 496 497 if (eh != NULL) { /* layer 2 packets are as on the wire */ 498 ip_off = ntohs(ip->ip_off); 499 ip_len = ntohs(ip->ip_len); 500 } else { 501 ip_off = ip->ip_off; 502 ip_len = ip->ip_len; 503 } 504 offset = ip_off & IP_OFFMASK; 505 switch (ip->ip_p) { 506 case IPPROTO_TCP: 507 len = snprintf(SNPARGS(proto, 0), "TCP %s", 508 inet_ntoa(ip->ip_src)); 509 if (offset == 0) 510 snprintf(SNPARGS(proto, len), ":%d %s:%d", 511 ntohs(tcp->th_sport), 512 inet_ntoa(ip->ip_dst), 513 ntohs(tcp->th_dport)); 514 else 515 snprintf(SNPARGS(proto, len), " %s", 516 inet_ntoa(ip->ip_dst)); 517 break; 518 519 case IPPROTO_UDP: 520 len = snprintf(SNPARGS(proto, 0), "UDP %s", 521 inet_ntoa(ip->ip_src)); 522 if (offset == 0) 523 snprintf(SNPARGS(proto, len), ":%d %s:%d", 524 ntohs(udp->uh_sport), 525 inet_ntoa(ip->ip_dst), 526 ntohs(udp->uh_dport)); 527 else 528 snprintf(SNPARGS(proto, len), " %s", 529 inet_ntoa(ip->ip_dst)); 530 break; 531 532 case IPPROTO_ICMP: 533 if (offset == 0) 534 len = snprintf(SNPARGS(proto, 0), 535 "ICMP:%u.%u ", 536 icmp->icmp_type, icmp->icmp_code); 537 else 538 len = snprintf(SNPARGS(proto, 0), "ICMP "); 539 len += snprintf(SNPARGS(proto, len), "%s", 540 inet_ntoa(ip->ip_src)); 541 snprintf(SNPARGS(proto, len), " %s", 542 inet_ntoa(ip->ip_dst)); 543 break; 544 545 default: 546 len = snprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p, 547 inet_ntoa(ip->ip_src)); 548 snprintf(SNPARGS(proto, len), " %s", 549 inet_ntoa(ip->ip_dst)); 550 break; 551 } 552 553 if (ip_off & (IP_MF | IP_OFFMASK)) 554 snprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)", 555 ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2), 556 offset << 3, 557 (ip_off & IP_MF) ? "+" : ""); 558 } 559 if (oif || m->m_pkthdr.rcvif) 560 log(LOG_SECURITY | LOG_INFO, 561 "ipfw: %d %s %s %s via %s%d%s\n", 562 f ? f->rulenum : -1, 563 action, proto, oif ? "out" : "in", 564 oif ? oif->if_name : m->m_pkthdr.rcvif->if_name, 565 oif ? oif->if_unit : m->m_pkthdr.rcvif->if_unit, 566 fragment); 567 else 568 log(LOG_SECURITY | LOG_INFO, 569 "ipfw: %d %s %s [no if info]%s\n", 570 f ? f->rulenum : -1, 571 action, proto, fragment); 572 if (limit_reached) 573 log(LOG_SECURITY | LOG_NOTICE, 574 "ipfw: limit %d reached on entry %d\n", 575 limit_reached, f ? f->rulenum : -1); 576} 577 578/* 579 * IMPORTANT: the hash function for dynamic rules must be commutative 580 * in source and destination (ip,port), because rules are bidirectional 581 * and we want to find both in the same bucket. 582 */ 583static __inline int 584hash_packet(struct ipfw_flow_id *id) 585{ 586 u_int32_t i; 587 588 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 589 i &= (curr_dyn_buckets - 1); 590 return i; 591} 592 593/** 594 * unlink a dynamic rule from a chain. prev is a pointer to 595 * the previous one, q is a pointer to the rule to delete, 596 * head is a pointer to the head of the queue. 597 * Modifies q and potentially also head. 598 */ 599#define UNLINK_DYN_RULE(prev, head, q) { \ 600 ipfw_dyn_rule *old_q = q; \ 601 \ 602 /* remove a refcount to the parent */ \ 603 if (q->dyn_type == O_LIMIT) \ 604 q->parent->count--; \ 605 DEB(printf("-- unlink entry 0x%08x %d -> 0x%08x %d, %d left\n", \ 606 (q->id.src_ip), (q->id.src_port), \ 607 (q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \ 608 if (prev != NULL) \ 609 prev->next = q = q->next; \ 610 else \ 611 head = q = q->next; \ 612 dyn_count--; \ 613 free(old_q, M_IPFW); } 614 615#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 616 617/** 618 * Remove dynamic rules pointing to "rule", or all of them if rule == NULL. 619 * 620 * If keep_me == NULL, rules are deleted even if not expired, 621 * otherwise only expired rules are removed. 622 * 623 * The value of the second parameter is also used to point to identify 624 * a rule we absolutely do not want to remove (e.g. because we are 625 * holding a reference to it -- this is the case with O_LIMIT_PARENT 626 * rules). The pointer is only used for comparison, so any non-null 627 * value will do. 628 */ 629static void 630remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me) 631{ 632 static u_int32_t last_remove = 0; 633 634#define FORCE (keep_me == NULL) 635 636 ipfw_dyn_rule *prev, *q; 637 int i, pass = 0, max_pass = 0; 638 639 if (ipfw_dyn_v == NULL || dyn_count == 0) 640 return; 641 /* do not expire more than once per second, it is useless */ 642 if (!FORCE && last_remove == time_second) 643 return; 644 last_remove = time_second; 645 646 /* 647 * because O_LIMIT refer to parent rules, during the first pass only 648 * remove child and mark any pending LIMIT_PARENT, and remove 649 * them in a second pass. 650 */ 651next_pass: 652 for (i = 0 ; i < curr_dyn_buckets ; i++) { 653 for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) { 654 /* 655 * Logic can become complex here, so we split tests. 656 */ 657 if (q == keep_me) 658 goto next; 659 if (rule != NULL && rule != q->rule) 660 goto next; /* not the one we are looking for */ 661 if (q->dyn_type == O_LIMIT_PARENT) { 662 /* 663 * handle parent in the second pass, 664 * record we need one. 665 */ 666 max_pass = 1; 667 if (pass == 0) 668 goto next; 669 if (FORCE && q->count != 0 ) { 670 /* XXX should not happen! */ 671 printf( "OUCH! cannot remove rule," 672 " count %d\n", q->count); 673 } 674 } else { 675 if (!FORCE && 676 !TIME_LEQ( q->expire, time_second )) 677 goto next; 678 } 679 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 680 continue; 681next: 682 prev=q; 683 q=q->next; 684 } 685 } 686 if (pass++ < max_pass) 687 goto next_pass; 688} 689 690 691/** 692 * lookup a dynamic rule. 693 */ 694static ipfw_dyn_rule * 695lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 696 struct tcphdr *tcp) 697{ 698 /* 699 * stateful ipfw extensions. 700 * Lookup into dynamic session queue 701 */ 702#define MATCH_REVERSE 0 703#define MATCH_FORWARD 1 704#define MATCH_NONE 2 705#define MATCH_UNKNOWN 3 706 int i, dir = MATCH_NONE; 707 ipfw_dyn_rule *prev, *q=NULL; 708 709 if (ipfw_dyn_v == NULL) 710 goto done; /* not found */ 711 i = hash_packet( pkt ); 712 for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) { 713 if (q->dyn_type == O_LIMIT_PARENT) 714 goto next; 715 if (TIME_LEQ( q->expire, time_second)) { /* expire entry */ 716 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 717 continue; 718 } 719 if ( pkt->proto == q->id.proto) { 720 if (pkt->src_ip == q->id.src_ip && 721 pkt->dst_ip == q->id.dst_ip && 722 pkt->src_port == q->id.src_port && 723 pkt->dst_port == q->id.dst_port ) { 724 dir = MATCH_FORWARD; 725 break; 726 } 727 if (pkt->src_ip == q->id.dst_ip && 728 pkt->dst_ip == q->id.src_ip && 729 pkt->src_port == q->id.dst_port && 730 pkt->dst_port == q->id.src_port ) { 731 dir = MATCH_REVERSE; 732 break; 733 } 734 } 735next: 736 prev = q; 737 q = q->next; 738 } 739 if (q == NULL) 740 goto done; /* q = NULL, not found */ 741 742 if ( prev != NULL) { /* found and not in front */ 743 prev->next = q->next; 744 q->next = ipfw_dyn_v[i]; 745 ipfw_dyn_v[i] = q; 746 } 747 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 748 u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST); 749 750#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 751#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 752 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8); 753 switch (q->state) { 754 case TH_SYN: /* opening */ 755 q->expire = time_second + dyn_syn_lifetime; 756 break; 757 case BOTH_SYN: /* move to established */ 758 case BOTH_SYN | TH_FIN : /* one side tries to close */ 759 case BOTH_SYN | (TH_FIN << 8) : 760 if (tcp) { 761#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 762 u_int32_t ack = ntohl(tcp->th_ack); 763 if (dir == MATCH_FORWARD) { 764 if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd)) 765 q->ack_fwd = ack; 766 else { /* ignore out-of-sequence */ 767 break; 768 } 769 } else { 770 if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev)) 771 q->ack_rev = ack; 772 else { /* ignore out-of-sequence */ 773 break; 774 } 775 } 776 } 777 q->expire = time_second + dyn_ack_lifetime; 778 break; 779 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 780 q->expire = time_second + dyn_fin_lifetime; 781 break; 782 default: 783#if 0 784 /* 785 * reset or some invalid combination, but can also 786 * occur if we use keep-state the wrong way. 787 */ 788 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 789 printf("invalid state: 0x%x\n", q->state); 790#endif 791 q->expire = time_second + dyn_rst_lifetime; 792 break; 793 } 794 } else if (pkt->proto == IPPROTO_UDP) { 795 q->expire = time_second + dyn_udp_lifetime; 796 } else { 797 /* other protocols */ 798 q->expire = time_second + dyn_short_lifetime; 799 } 800done: 801 if (match_direction) 802 *match_direction = dir; 803 return q; 804} 805 806static void 807realloc_dynamic_table(void) 808{ 809 /* try reallocation, make sure we have a power of 2 */ 810 811 if ((dyn_buckets & (dyn_buckets-1)) != 0) { /* not a power of 2 */ 812 dyn_buckets = curr_dyn_buckets; /* reset */ 813 return; 814 } 815 curr_dyn_buckets = dyn_buckets; 816 if (ipfw_dyn_v != NULL) 817 free(ipfw_dyn_v, M_IPFW); 818 ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof(ipfw_dyn_rule *), 819 M_IPFW, M_DONTWAIT | M_ZERO); 820} 821 822/** 823 * Install state of type 'type' for a dynamic session. 824 * The hash table contains two type of rules: 825 * - regular rules (O_KEEP_STATE) 826 * - rules for sessions with limited number of sess per user 827 * (O_LIMIT). When they are created, the parent is 828 * increased by 1, and decreased on delete. In this case, 829 * the third parameter is the parent rule and not the chain. 830 * - "parent" rules for the above (O_LIMIT_PARENT). 831 */ 832static ipfw_dyn_rule * 833add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule) 834{ 835 ipfw_dyn_rule *r; 836 int i; 837 838 if (ipfw_dyn_v == NULL || 839 (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) { 840 realloc_dynamic_table(); 841 if (ipfw_dyn_v == NULL) 842 return NULL; /* failed ! */ 843 } 844 i = hash_packet(id); 845 846 r = malloc(sizeof *r, M_IPFW, M_DONTWAIT | M_ZERO); 847 if (r == NULL) { 848 printf ("sorry cannot allocate state\n"); 849 return NULL; 850 } 851 852 /* increase refcount on parent, and set pointer */ 853 if (dyn_type == O_LIMIT) { 854 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 855 if ( parent->dyn_type != O_LIMIT_PARENT) 856 panic("invalid parent"); 857 parent->count++; 858 r->parent = parent; 859 rule = parent->rule; 860 } 861 862 r->id = *id; 863 r->expire = time_second + dyn_syn_lifetime; 864 r->rule = rule; 865 r->dyn_type = dyn_type; 866 r->pcnt = r->bcnt = 0; 867 r->count = 0; 868 869 r->bucket = i; 870 r->next = ipfw_dyn_v[i]; 871 ipfw_dyn_v[i] = r; 872 dyn_count++; 873 DEB(printf("-- add dyn entry ty %d 0x%08x %d -> 0x%08x %d, total %d\n", 874 dyn_type, 875 (r->id.src_ip), (r->id.src_port), 876 (r->id.dst_ip), (r->id.dst_port), 877 dyn_count ); ) 878 return r; 879} 880 881/** 882 * lookup dynamic parent rule using pkt and rule as search keys. 883 * If the lookup fails, then install one. 884 */ 885static ipfw_dyn_rule * 886lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule) 887{ 888 ipfw_dyn_rule *q; 889 int i; 890 891 if (ipfw_dyn_v) { 892 i = hash_packet( pkt ); 893 for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next) 894 if (q->dyn_type == O_LIMIT_PARENT && 895 rule== q->rule && 896 pkt->proto == q->id.proto && 897 pkt->src_ip == q->id.src_ip && 898 pkt->dst_ip == q->id.dst_ip && 899 pkt->src_port == q->id.src_port && 900 pkt->dst_port == q->id.dst_port) { 901 q->expire = time_second + dyn_short_lifetime; 902 DEB(printf("lookup_dyn_parent found 0x%p\n",q);) 903 return q; 904 } 905 } 906 return add_dyn_rule(pkt, O_LIMIT_PARENT, rule); 907} 908 909/** 910 * Install dynamic state for rule type cmd->o.opcode 911 * 912 * Returns 1 (failure) if state is not installed because of errors or because 913 * session limitations are enforced. 914 */ 915static int 916install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 917 struct ip_fw_args *args) 918{ 919 static int last_log; 920 921 ipfw_dyn_rule *q; 922 923 DEB(printf("-- install state type %d 0x%08x %u -> 0x%08x %u\n", 924 cmd->o.opcode, 925 (args->f_id.src_ip), (args->f_id.src_port), 926 (args->f_id.dst_ip), (args->f_id.dst_port) );) 927 928 q = lookup_dyn_rule(&args->f_id, NULL, NULL); 929 930 if (q != NULL) { /* should never occur */ 931 if (last_log != time_second) { 932 last_log = time_second; 933 printf(" install_state: entry already present, done\n"); 934 } 935 return 0; 936 } 937 938 if (dyn_count >= dyn_max) 939 /* 940 * Run out of slots, try to remove any expired rule. 941 */ 942 remove_dyn_rule(NULL, (ipfw_dyn_rule *)1); 943 944 if (dyn_count >= dyn_max) { 945 if (last_log != time_second) { 946 last_log = time_second; 947 printf("install_state: Too many dynamic rules\n"); 948 } 949 return 1; /* cannot install, notify caller */ 950 } 951 952 switch (cmd->o.opcode) { 953 case O_KEEP_STATE: /* bidir rule */ 954 add_dyn_rule(&args->f_id, O_KEEP_STATE, rule); 955 break; 956 957 case O_LIMIT: /* limit number of sessions */ 958 { 959 u_int16_t limit_mask = cmd->limit_mask; 960 struct ipfw_flow_id id; 961 ipfw_dyn_rule *parent; 962 963 DEB(printf("installing dyn-limit rule %d\n", cmd->conn_limit);) 964 965 id.dst_ip = id.src_ip = 0; 966 id.dst_port = id.src_port = 0; 967 id.proto = args->f_id.proto; 968 969 if (limit_mask & DYN_SRC_ADDR) 970 id.src_ip = args->f_id.src_ip; 971 if (limit_mask & DYN_DST_ADDR) 972 id.dst_ip = args->f_id.dst_ip; 973 if (limit_mask & DYN_SRC_PORT) 974 id.src_port = args->f_id.src_port; 975 if (limit_mask & DYN_DST_PORT) 976 id.dst_port = args->f_id.dst_port; 977 parent = lookup_dyn_parent(&id, rule); 978 if (parent == NULL) { 979 printf("add parent failed\n"); 980 return 1; 981 } 982 if (parent->count >= cmd->conn_limit) { 983 /* 984 * See if we can remove some expired rule. 985 */ 986 remove_dyn_rule(rule, parent); 987 if (parent->count >= cmd->conn_limit) { 988 if (fw_verbose && last_log != time_second) { 989 last_log = time_second; 990 printf( 991 "drop session, too many entries\n"); 992 } 993 return 1; 994 } 995 } 996 add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent); 997 } 998 break; 999 default: 1000 printf("unknown dynamic rule type %u\n", cmd->o.opcode); 1001 return 1; 1002 } 1003 lookup_dyn_rule(&args->f_id, NULL, NULL); /* XXX just set lifetime */ 1004 return 0; 1005} 1006 1007/* 1008 * Transmit a TCP packet, containing either a RST or a keepalive. 1009 * When flags & TH_RST, we are sending a RST packet, because of a 1010 * "reset" action matched the packet. 1011 * Otherwise we are sending a keepalive, and flags & TH_ 1012 */ 1013static void 1014send_pkt(struct ipfw_flow_id *id, u_int32_t seq, u_int32_t ack, int flags) 1015{ 1016 struct mbuf *m; 1017 struct ip *ip; 1018 struct tcphdr *tcp; 1019 struct route sro; /* fake route */ 1020 1021 MGETHDR(m, M_DONTWAIT, MT_HEADER); 1022 if (m == 0) 1023 return; 1024 m->m_pkthdr.rcvif = (struct ifnet *)0; 1025 m->m_pkthdr.len = m->m_len = sizeof(struct ip) + sizeof(struct tcphdr); 1026 m->m_data += max_linkhdr; 1027 1028 ip = mtod(m, struct ip *); 1029 bzero(ip, m->m_len); 1030 tcp = (struct tcphdr *)(ip + 1); /* no IP options */ 1031 ip->ip_p = IPPROTO_TCP; 1032 tcp->th_off = 5; 1033 /* 1034 * Assume we are sending a RST (or a keepalive in the reverse 1035 * direction), swap src and destination addresses and ports. 1036 */ 1037 ip->ip_src.s_addr = htonl(id->dst_ip); 1038 ip->ip_dst.s_addr = htonl(id->src_ip); 1039 tcp->th_sport = htons(id->dst_port); 1040 tcp->th_dport = htons(id->src_port); 1041 if (flags & TH_RST) { /* we are sending a RST */ 1042 if (flags & TH_ACK) { 1043 tcp->th_seq = htonl(ack); 1044 tcp->th_ack = htonl(0); 1045 tcp->th_flags = TH_RST; 1046 } else { 1047 if (flags & TH_SYN) 1048 seq++; 1049 tcp->th_seq = htonl(0); 1050 tcp->th_ack = htonl(seq); 1051 tcp->th_flags = TH_RST | TH_ACK; 1052 } 1053 } else { 1054 /* 1055 * We are sending a keepalive. flags & TH_SYN determines 1056 * the direction, forward if set, reverse if clear. 1057 * NOTE: seq and ack are always assumed to be correct 1058 * as set by the caller. This may be confusing... 1059 */ 1060 if (flags & TH_SYN) { 1061 /* 1062 * we have to rewrite the correct addresses! 1063 */ 1064 ip->ip_dst.s_addr = htonl(id->dst_ip); 1065 ip->ip_src.s_addr = htonl(id->src_ip); 1066 tcp->th_dport = htons(id->dst_port); 1067 tcp->th_sport = htons(id->src_port); 1068 } 1069 tcp->th_seq = htonl(seq); 1070 tcp->th_ack = htonl(ack); 1071 tcp->th_flags = TH_ACK; 1072 } 1073 /* 1074 * set ip_len to the payload size so we can compute 1075 * the tcp checksum on the pseudoheader 1076 * XXX check this, could save a couple of words ? 1077 */ 1078 ip->ip_len = htons(sizeof(struct tcphdr)); 1079 tcp->th_sum = in_cksum(m, m->m_pkthdr.len); 1080 /* 1081 * now fill fields left out earlier 1082 */ 1083 ip->ip_ttl = ip_defttl; 1084 ip->ip_len = m->m_pkthdr.len; 1085 bzero (&sro, sizeof (sro)); 1086 ip_rtaddr(ip->ip_dst, &sro); 1087 ip_output(m, NULL, &sro, 0, NULL); 1088 if (sro.ro_rt) 1089 RTFREE(sro.ro_rt); 1090} 1091 1092/* 1093 * sends a reject message, consuming the mbuf passed as an argument. 1094 */ 1095static void 1096send_reject(struct ip_fw_args *args, int code, int offset, int ip_len) 1097{ 1098printf("+++ send reject\n"); 1099 if (code != ICMP_REJECT_RST) /* Send an ICMP unreach */ 1100 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 1101 else if (offset == 0 && args->f_id.proto == IPPROTO_TCP) { 1102 struct tcphdr *const tcp = 1103 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 1104 if ( (tcp->th_flags & TH_RST) == 0) 1105 send_pkt(&(args->f_id), ntohl(tcp->th_seq), 1106 ntohl(tcp->th_ack), 1107 tcp->th_flags | TH_RST); 1108 m_freem(args->m); 1109 } else 1110 m_freem(args->m); 1111 args->m = NULL; 1112} 1113 1114/** 1115 * 1116 * Given an ip_fw *, lookup_next_rule will return a pointer 1117 * to the next rule, which can be either the jump 1118 * target (for skipto instructions) or the next one in the list (in 1119 * all other cases including a missing jump target). 1120 * The result is also written in the "next_rule" field of the rule. 1121 * Backward jumps are not allowed, so start looking from the next 1122 * rule... 1123 * 1124 * This never returns NULL -- in case we do not have an exact match, 1125 * the next rule is returned. When the ruleset is changed, 1126 * pointers are flushed so we are always correct. 1127 */ 1128 1129static struct ip_fw * 1130lookup_next_rule(struct ip_fw *me) 1131{ 1132 struct ip_fw *rule = NULL; 1133 ipfw_insn *cmd; 1134 1135 /* look for action, in case it is a skipto */ 1136 cmd = ACTION_PTR(me); 1137 if ( cmd->opcode == O_SKIPTO ) 1138 for (rule = me->next; rule ; rule = rule->next) 1139 if (rule->rulenum >= cmd->arg1) 1140 break; 1141 if (rule == NULL) /* failure or not a skipto */ 1142 rule = me->next; 1143 me->next_rule = rule; 1144 return rule; 1145} 1146 1147/* 1148 * The main check routine for the firewall. 1149 * 1150 * All arguments are in args so we can modify them and return them 1151 * back to the caller. 1152 * 1153 * Parameters: 1154 * 1155 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 1156 * Starts with the IP header. 1157 * args->eh (in) Mac header if present, or NULL for layer3 packet. 1158 * args->oif Outgoing interface, or NULL if packet is incoming. 1159 * The incoming interface is in the mbuf. (in) 1160 * args->divert_rule (in/out) 1161 * Skip up to the first rule past this rule number; 1162 * upon return, non-zero port number for divert or tee. 1163 * 1164 * args->rule Pointer to the last matching rule (in/out) 1165 * args->next_hop Socket we are forwarding to (out). 1166 * args->f_id Addresses grabbed from the packet (out) 1167 * 1168 * Return value: 1169 * 1170 * IP_FW_PORT_DENY_FLAG the packet must be dropped. 1171 * 0 The packet is to be accepted and routed normally OR 1172 * the packet was denied/rejected and has been dropped; 1173 * in the latter case, *m is equal to NULL upon return. 1174 * port Divert the packet to port, with these caveats: 1175 * 1176 * - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead 1177 * of diverting it (ie, 'ipfw tee'). 1178 * 1179 * - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower 1180 * 16 bits as a dummynet pipe number instead of diverting 1181 */ 1182 1183static int 1184ipfw_chk(struct ip_fw_args *args) 1185{ 1186 /* 1187 * Local variables hold state during the processing of a packet. 1188 * 1189 * IMPORTANT NOTE: to speed up the processing of rules, there 1190 * are some assumption on the values of the variables, which 1191 * are documented here. Should you change them, please check 1192 * the implementation of the various instructions to make sure 1193 * that they still work. 1194 */ 1195 /* 1196 * args->eh The MAC header. It is non-null for a layer2 1197 * packet, it is NULL for a layer-3 packet. 1198 * 1199 * m | args->m Pointer to the mbuf, as received from the caller. 1200 * It may change if ipfw_chk() does an m_pullup, or if it 1201 * consumes the packet because it calls send_reject(). 1202 * XXX This has to change, so that ipfw_chk() never modifies 1203 * or consumes the buffer. 1204 * ip is simply an alias of the value of m, and it is kept 1205 * in sync with it (the packet is supposed to start with 1206 * the ip header). 1207 */ 1208 struct mbuf *m = args->m; 1209 struct ip *ip = mtod(m, struct ip *); 1210 1211 /* 1212 * oif | args->oif If NULL, ipfw_chk has been called on the 1213 * inbound path (ether_input, bdg_forward, ip_input). 1214 * If non-NULL, ipfw_chk has been called on the outbound path 1215 * (ether_output, ip_output). 1216 */ 1217 struct ifnet *oif = args->oif; 1218 1219 struct ip_fw *f = NULL; /* matching rule */ 1220 int retval = 0; 1221 1222 /* 1223 * hlen The length of the IPv4 header. 1224 * hlen >0 means we have an IPv4 packet. 1225 */ 1226 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 1227 1228 /* 1229 * offset The offset of a fragment. offset != 0 means that 1230 * we have a fragment at this offset of an IPv4 packet. 1231 * offset == 0 means that (if this is an IPv4 packet) 1232 * this is the first or only fragment. 1233 */ 1234 u_short offset = 0; 1235 1236 /* 1237 * Local copies of addresses. They are only valid if we have 1238 * an IP packet. 1239 * 1240 * proto The protocol. Set to 0 for non-ip packets, 1241 * or to the protocol read from the packet otherwise. 1242 * proto != 0 means that we have an IPv4 packet. 1243 * 1244 * src_port, dst_port port numbers, in HOST format. Only 1245 * valid for TCP and UDP packets. 1246 * 1247 * src_ip, dst_ip ip addresses, in NETWORK format. 1248 * Only valid for IPv4 packets. 1249 */ 1250 u_int8_t proto; 1251 u_int16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 1252 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 1253 u_int16_t ip_len=0; 1254 int dyn_dir = MATCH_UNKNOWN; 1255 ipfw_dyn_rule *q = NULL; 1256 1257 /* 1258 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 1259 * MATCH_NONE when checked and not matched (q = NULL), 1260 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 1261 */ 1262 1263 if (args->eh == NULL || /* layer 3 packet */ 1264 ( m->m_pkthdr.len >= sizeof(struct ip) && 1265 ntohs(args->eh->ether_type) == ETHERTYPE_IP)) 1266 hlen = ip->ip_hl << 2; 1267 1268 /* 1269 * Collect parameters into local variables for faster matching. 1270 */ 1271 if (hlen == 0) { /* do not grab addresses for non-ip pkts */ 1272 proto = args->f_id.proto = 0; /* mark f_id invalid */ 1273 goto after_ip_checks; 1274 } 1275 1276 proto = args->f_id.proto = ip->ip_p; 1277 src_ip = ip->ip_src; 1278 dst_ip = ip->ip_dst; 1279 if (args->eh != NULL) { /* layer 2 packets are as on the wire */ 1280 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1281 ip_len = ntohs(ip->ip_len); 1282 } else { 1283 offset = ip->ip_off & IP_OFFMASK; 1284 ip_len = ip->ip_len; 1285 } 1286 1287#define PULLUP_TO(len) \ 1288 do { \ 1289 if ((m)->m_len < (len)) { \ 1290 args->m = m = m_pullup(m, (len)); \ 1291 if (m == 0) \ 1292 goto pullup_failed; \ 1293 ip = mtod(m, struct ip *); \ 1294 } \ 1295 } while (0) 1296 1297 if (offset == 0) { 1298 switch (proto) { 1299 case IPPROTO_TCP: 1300 { 1301 struct tcphdr *tcp; 1302 1303 PULLUP_TO(hlen + sizeof(struct tcphdr)); 1304 tcp = L3HDR(struct tcphdr, ip); 1305 dst_port = tcp->th_dport; 1306 src_port = tcp->th_sport; 1307 args->f_id.flags = tcp->th_flags; 1308 } 1309 break; 1310 1311 case IPPROTO_UDP: 1312 { 1313 struct udphdr *udp; 1314 1315 PULLUP_TO(hlen + sizeof(struct udphdr)); 1316 udp = L3HDR(struct udphdr, ip); 1317 dst_port = udp->uh_dport; 1318 src_port = udp->uh_sport; 1319 } 1320 break; 1321 1322 case IPPROTO_ICMP: 1323 PULLUP_TO(hlen + 4); /* type, code and checksum. */ 1324 args->f_id.flags = L3HDR(struct icmp, ip)->icmp_type; 1325 break; 1326 1327 default: 1328 break; 1329 } 1330#undef PULLUP_TO 1331 } 1332 1333 args->f_id.src_ip = ntohl(src_ip.s_addr); 1334 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1335 args->f_id.src_port = src_port = ntohs(src_port); 1336 args->f_id.dst_port = dst_port = ntohs(dst_port); 1337 1338after_ip_checks: 1339 if (args->rule) { 1340 /* 1341 * Packet has already been tagged. Look for the next rule 1342 * to restart processing. 1343 * 1344 * If fw_one_pass != 0 then just accept it. 1345 * XXX should not happen here, but optimized out in 1346 * the caller. 1347 */ 1348 if (fw_one_pass) 1349 return 0; 1350 1351 f = args->rule->next_rule; 1352 if (f == NULL) 1353 f = lookup_next_rule(args->rule); 1354 } else { 1355 /* 1356 * Find the starting rule. It can be either the first 1357 * one, or the one after divert_rule if asked so. 1358 */ 1359 int skipto = args->divert_rule; 1360 1361 f = layer3_chain; 1362 if (args->eh == NULL && skipto != 0) { 1363 if (skipto >= IPFW_DEFAULT_RULE) 1364 return(IP_FW_PORT_DENY_FLAG); /* invalid */ 1365 while (f && f->rulenum <= skipto) 1366 f = f->next; 1367 if (f == NULL) /* drop packet */ 1368 return(IP_FW_PORT_DENY_FLAG); 1369 } 1370 } 1371 args->divert_rule = 0; /* reset to avoid confusion later */ 1372 1373 /* 1374 * Now scan the rules, and parse microinstructions for each rule. 1375 */ 1376 for (; f; f = f->next) { 1377 int l, cmdlen; 1378 ipfw_insn *cmd; 1379 int skip_or; /* skip rest of OR block */ 1380 1381again: 1382 if (set_disable & (1 << f->set) ) 1383 continue; 1384 1385 skip_or = 0; 1386 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1387 l -= cmdlen, cmd += cmdlen) { 1388 int match; 1389 1390 /* 1391 * check_body is a jump target used when we find a 1392 * CHECK_STATE, and need to jump to the body of 1393 * the target rule. 1394 */ 1395 1396check_body: 1397 cmdlen = F_LEN(cmd); 1398 /* 1399 * An OR block (insn_1 || .. || insn_n) has the 1400 * F_OR bit set in all but the last instruction. 1401 * The first match will set "skip_or", and cause 1402 * the following instructions to be skipped until 1403 * past the one with the F_OR bit clear. 1404 */ 1405 if (skip_or) { /* skip this instruction */ 1406 if ((cmd->len & F_OR) == 0) 1407 skip_or = 0; /* next one is good */ 1408 continue; 1409 } 1410 match = 0; /* set to 1 if we succeed */ 1411 1412 switch (cmd->opcode) { 1413 /* 1414 * The first set of opcodes compares the packet's 1415 * fields with some pattern, setting 'match' if a 1416 * match is found. At the end of the loop there is 1417 * logic to deal with F_NOT and F_OR flags associated 1418 * with the opcode. 1419 */ 1420 case O_NOP: 1421 match = 1; 1422 break; 1423 1424 case O_FORWARD_MAC: 1425 printf("ipfw: opcode %d unimplemented\n", 1426 cmd->opcode); 1427 break; 1428 1429 case O_GID: 1430 case O_UID: 1431 /* 1432 * We only check offset == 0 && proto != 0, 1433 * as this ensures that we have an IPv4 1434 * packet with the ports info. 1435 */ 1436 if (offset!=0) 1437 break; 1438 { 1439 struct inpcbinfo *pi; 1440 int wildcard; 1441 struct inpcb *pcb; 1442 1443 if (proto == IPPROTO_TCP) { 1444 wildcard = 0; 1445 pi = &tcbinfo; 1446 } else if (proto == IPPROTO_UDP) { 1447 wildcard = 1; 1448 pi = &udbinfo; 1449 } else 1450 break; 1451 1452 pcb = (oif) ? 1453 in_pcblookup_hash(pi, 1454 dst_ip, htons(dst_port), 1455 src_ip, htons(src_port), 1456 wildcard, oif) : 1457 in_pcblookup_hash(pi, 1458 src_ip, htons(src_port), 1459 dst_ip, htons(dst_port), 1460 wildcard, NULL); 1461 1462 if (pcb == NULL || pcb->inp_socket == NULL) 1463 break; 1464#if __FreeBSD_version < 500034 1465#define socheckuid(a,b) ((a)->so_cred->cr_uid == (b)) 1466#endif 1467 if (cmd->opcode == O_UID) { 1468 match = 1469 socheckuid(pcb->inp_socket, 1470 (uid_t)((ipfw_insn_u32 *)cmd)->d[0]); 1471 } else { 1472 match = groupmember( 1473 (uid_t)((ipfw_insn_u32 *)cmd)->d[0], 1474 pcb->inp_socket->so_cred); 1475 } 1476 } 1477 break; 1478 1479 case O_RECV: 1480 match = iface_match(m->m_pkthdr.rcvif, 1481 (ipfw_insn_if *)cmd); 1482 break; 1483 1484 case O_XMIT: 1485 match = iface_match(oif, (ipfw_insn_if *)cmd); 1486 break; 1487 1488 case O_VIA: 1489 match = iface_match(oif ? oif : 1490 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd); 1491 break; 1492 1493 case O_MACADDR2: 1494 if (args->eh != NULL) { /* have MAC header */ 1495 u_int32_t *want = (u_int32_t *) 1496 ((ipfw_insn_mac *)cmd)->addr; 1497 u_int32_t *mask = (u_int32_t *) 1498 ((ipfw_insn_mac *)cmd)->mask; 1499 u_int32_t *hdr = (u_int32_t *)args->eh; 1500 1501 match = 1502 ( want[0] == (hdr[0] & mask[0]) && 1503 want[1] == (hdr[1] & mask[1]) && 1504 want[2] == (hdr[2] & mask[2]) ); 1505 } 1506 break; 1507 1508 case O_MAC_TYPE: 1509 if (args->eh != NULL) { 1510 u_int16_t t = 1511 ntohs(args->eh->ether_type); 1512 u_int16_t *p = 1513 ((ipfw_insn_u16 *)cmd)->ports; 1514 int i; 1515 1516 for (i = cmdlen - 1; !match && i>0; 1517 i--, p += 2) 1518 match = (t>=p[0] && t<=p[1]); 1519 } 1520 break; 1521 1522 case O_FRAG: 1523 match = (hlen > 0 && offset != 0); 1524 break; 1525 1526 case O_IN: /* "out" is "not in" */ 1527 match = (oif == NULL); 1528 break; 1529 1530 case O_LAYER2: 1531 match = (args->eh != NULL); 1532 break; 1533 1534 case O_PROTO: 1535 /* 1536 * We do not allow an arg of 0 so the 1537 * check of "proto" only suffices. 1538 */ 1539 match = (proto == cmd->arg1); 1540 break; 1541 1542 case O_IP_SRC: 1543 match = (hlen > 0 && 1544 ((ipfw_insn_ip *)cmd)->addr.s_addr == 1545 src_ip.s_addr); 1546 break; 1547 1548 case O_IP_SRC_MASK: 1549 match = (hlen > 0 && 1550 ((ipfw_insn_ip *)cmd)->addr.s_addr == 1551 (src_ip.s_addr & 1552 ((ipfw_insn_ip *)cmd)->mask.s_addr)); 1553 break; 1554 1555 case O_IP_SRC_ME: 1556 if (hlen > 0) { 1557 struct ifnet *tif; 1558 1559 INADDR_TO_IFP(src_ip, tif); 1560 match = (tif != NULL); 1561 } 1562 break; 1563 1564 case O_IP_DST_SET: 1565 case O_IP_SRC_SET: 1566 if (hlen > 0) { 1567 u_int32_t *d = (u_int32_t *)(cmd+1); 1568 u_int32_t addr = 1569 cmd->opcode == O_IP_DST_SET ? 1570 args->f_id.src_ip : 1571 args->f_id.dst_ip; 1572 1573 if (addr < d[0]) 1574 break; 1575 addr -= d[0]; /* subtract base */ 1576 match = (addr < cmd->arg1) && 1577 ( d[ 1 + (addr>>5)] & 1578 (1<<(addr & 0x1f)) ); 1579 } 1580 break; 1581 1582 case O_IP_DST: 1583 match = (hlen > 0 && 1584 ((ipfw_insn_ip *)cmd)->addr.s_addr == 1585 dst_ip.s_addr); 1586 break; 1587 1588 case O_IP_DST_MASK: 1589 match = (hlen > 0) && 1590 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1591 (dst_ip.s_addr & 1592 ((ipfw_insn_ip *)cmd)->mask.s_addr)); 1593 break; 1594 1595 case O_IP_DST_ME: 1596 if (hlen > 0) { 1597 struct ifnet *tif; 1598 1599 INADDR_TO_IFP(dst_ip, tif); 1600 match = (tif != NULL); 1601 } 1602 break; 1603 1604 case O_IP_SRCPORT: 1605 case O_IP_DSTPORT: 1606 /* 1607 * offset == 0 && proto != 0 is enough 1608 * to guarantee that we have an IPv4 1609 * packet with port info. 1610 */ 1611 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP) 1612 && offset == 0) { 1613 u_int16_t x = 1614 (cmd->opcode == O_IP_SRCPORT) ? 1615 src_port : dst_port ; 1616 u_int16_t *p = 1617 ((ipfw_insn_u16 *)cmd)->ports; 1618 int i; 1619 1620 for (i = cmdlen - 1; !match && i>0; 1621 i--, p += 2) 1622 match = (x>=p[0] && x<=p[1]); 1623 } 1624 break; 1625 1626 case O_ICMPTYPE: 1627 match = (offset == 0 && proto==IPPROTO_ICMP && 1628 icmptype_match(ip, (ipfw_insn_u32 *)cmd) ); 1629 break; 1630 1631 case O_IPOPT: 1632 match = (hlen > 0 && ipopts_match(ip, cmd) ); 1633 break; 1634 1635 case O_IPVER: 1636 match = (hlen > 0 && cmd->arg1 == ip->ip_v); 1637 break; 1638 1639 case O_IPTTL: 1640 match = (hlen > 0 && cmd->arg1 == ip->ip_ttl); 1641 break; 1642 1643 case O_IPID: 1644 match = (hlen > 0 && 1645 cmd->arg1 == ntohs(ip->ip_id)); 1646 break; 1647 1648 case O_IPLEN: 1649 match = (hlen > 0 && cmd->arg1 == ip_len); 1650 break; 1651 1652 case O_IPPRECEDENCE: 1653 match = (hlen > 0 && 1654 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 1655 break; 1656 1657 case O_IPTOS: 1658 match = (hlen > 0 && 1659 flags_match(cmd, ip->ip_tos)); 1660 break; 1661 1662 case O_TCPFLAGS: 1663 match = (proto == IPPROTO_TCP && offset == 0 && 1664 flags_match(cmd, 1665 L3HDR(struct tcphdr,ip)->th_flags)); 1666 break; 1667 1668 case O_TCPOPTS: 1669 match = (proto == IPPROTO_TCP && offset == 0 && 1670 tcpopts_match(ip, cmd)); 1671 break; 1672 1673 case O_TCPSEQ: 1674 match = (proto == IPPROTO_TCP && offset == 0 && 1675 ((ipfw_insn_u32 *)cmd)->d[0] == 1676 L3HDR(struct tcphdr,ip)->th_seq); 1677 break; 1678 1679 case O_TCPACK: 1680 match = (proto == IPPROTO_TCP && offset == 0 && 1681 ((ipfw_insn_u32 *)cmd)->d[0] == 1682 L3HDR(struct tcphdr,ip)->th_ack); 1683 break; 1684 1685 case O_TCPWIN: 1686 match = (proto == IPPROTO_TCP && offset == 0 && 1687 cmd->arg1 == 1688 L3HDR(struct tcphdr,ip)->th_win); 1689 break; 1690 1691 case O_ESTAB: 1692 /* reject packets which have SYN only */ 1693 /* XXX should i also check for TH_ACK ? */ 1694 match = (proto == IPPROTO_TCP && offset == 0 && 1695 (L3HDR(struct tcphdr,ip)->th_flags & 1696 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 1697 break; 1698 1699 case O_LOG: 1700 if (fw_verbose) 1701 ipfw_log(f, hlen, args->eh, m, oif); 1702 match = 1; 1703 break; 1704 1705 case O_PROB: 1706 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 1707 break; 1708 1709 /* 1710 * The second set of opcodes represents 'actions', 1711 * i.e. the terminal part of a rule once the packet 1712 * matches all previous patterns. 1713 * Typically there is only one action for each rule, 1714 * and the opcode is stored at the end of the rule 1715 * (but there are exceptions -- see below). 1716 * 1717 * In general, here we set retval and terminate the 1718 * outer loop (would be a 'break 3' in some language, 1719 * but we need to do a 'goto done'). 1720 * 1721 * Exceptions: 1722 * O_COUNT and O_SKIPTO actions: 1723 * instead of terminating, we jump to the next rule 1724 * ('goto next_rule', equivalent to a 'break 2'), 1725 * or to the SKIPTO target ('goto again' after 1726 * having set f, cmd and l), respectively. 1727 * 1728 * O_LIMIT and O_KEEP_STATE: these opcodes are 1729 * not real 'actions', and are stored right 1730 * before the 'action' part of the rule. 1731 * These opcodes try to install an entry in the 1732 * state tables; if successful, we continue with 1733 * the next opcode (match=1; break;), otherwise 1734 * the packet * must be dropped 1735 * ('goto done' after setting retval); 1736 * 1737 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 1738 * cause a lookup of the state table, and a jump 1739 * to the 'action' part of the parent rule 1740 * ('goto check_body') if an entry is found, or 1741 * (CHECK_STATE only) a jump to the next rule if 1742 * the entry is not found ('goto next_rule'). 1743 * The result of the lookup is cached to make 1744 * further instances of these opcodes are 1745 * effectively NOPs. 1746 */ 1747 case O_LIMIT: 1748 case O_KEEP_STATE: 1749 if (install_state(f, 1750 (ipfw_insn_limit *)cmd, args)) { 1751 retval = IP_FW_PORT_DENY_FLAG; 1752 goto done; /* error/limit violation */ 1753 } 1754 match = 1; 1755 break; 1756 1757 case O_PROBE_STATE: 1758 case O_CHECK_STATE: 1759 /* 1760 * dynamic rules are checked at the first 1761 * keep-state or check-state occurrence, 1762 * with the result being stored in dyn_dir. 1763 * The compiler introduces a PROBE_STATE 1764 * instruction for us when we have a 1765 * KEEP_STATE (because PROBE_STATE needs 1766 * to be run first). 1767 */ 1768 if (dyn_dir == MATCH_UNKNOWN && 1769 (q = lookup_dyn_rule(&args->f_id, 1770 &dyn_dir, proto == IPPROTO_TCP ? 1771 L3HDR(struct tcphdr, ip) : NULL)) 1772 != NULL) { 1773 /* 1774 * Found dynamic entry, update stats 1775 * and jump to the 'action' part of 1776 * the parent rule. 1777 */ 1778 q->pcnt++; 1779 q->bcnt += ip_len; 1780 f = q->rule; 1781 cmd = ACTION_PTR(f); 1782 l = f->cmd_len - f->act_ofs; 1783 goto check_body; 1784 } 1785 /* 1786 * Dynamic entry not found. If CHECK_STATE, 1787 * skip to next rule, if PROBE_STATE just 1788 * ignore and continue with next opcode. 1789 */ 1790 if (cmd->opcode == O_CHECK_STATE) 1791 goto next_rule; 1792 match = 1; 1793 break; 1794 1795 case O_ACCEPT: 1796 retval = 0; /* accept */ 1797 goto done; 1798 1799 case O_PIPE: 1800 case O_QUEUE: 1801 args->rule = f; /* report matching rule */ 1802 retval = cmd->arg1 | IP_FW_PORT_DYNT_FLAG; 1803 goto done; 1804 1805 case O_DIVERT: 1806 case O_TEE: 1807 if (args->eh) /* not on layer 2 */ 1808 break; 1809 args->divert_rule = f->rulenum; 1810 retval = (cmd->opcode == O_DIVERT) ? 1811 cmd->arg1 : 1812 cmd->arg1 | IP_FW_PORT_TEE_FLAG; 1813 goto done; 1814 1815 case O_COUNT: 1816 case O_SKIPTO: 1817 f->pcnt++; /* update stats */ 1818 f->bcnt += ip_len; 1819 f->timestamp = time_second; 1820 if (cmd->opcode == O_COUNT) 1821 goto next_rule; 1822 /* handle skipto */ 1823 if (f->next_rule == NULL) 1824 lookup_next_rule(f); 1825 f = f->next_rule; 1826 goto again; 1827 1828 case O_REJECT: 1829 /* 1830 * Drop the packet and send a reject notice 1831 * if the packet is not ICMP (or is an ICMP 1832 * query), and it is not multicast/broadcast. 1833 */ 1834 if (hlen > 0 && 1835 (proto != IPPROTO_ICMP || 1836 is_icmp_query(ip)) && 1837 !(m->m_flags & (M_BCAST|M_MCAST)) && 1838 !IN_MULTICAST(dst_ip.s_addr)) { 1839 send_reject(args, cmd->arg1, 1840 offset,ip_len); 1841 m = args->m; 1842 } 1843 /* FALLTHROUGH */ 1844 case O_DENY: 1845 retval = IP_FW_PORT_DENY_FLAG; 1846 goto done; 1847 1848 case O_FORWARD_IP: 1849 if (args->eh) /* not valid on layer2 pkts */ 1850 break; 1851 if (!q || dyn_dir == MATCH_FORWARD) 1852 args->next_hop = 1853 &((ipfw_insn_sa *)cmd)->sa; 1854 retval = 0; 1855 goto done; 1856 1857 default: 1858 panic("-- unknown opcode %d\n", cmd->opcode); 1859 } /* end of switch() on opcodes */ 1860 1861 if (cmd->len & F_NOT) 1862 match = !match; 1863 1864 if (match) { 1865 if (cmd->len & F_OR) 1866 skip_or = 1; 1867 } else { 1868 if (!(cmd->len & F_OR)) /* not an OR block, */ 1869 break; /* try next rule */ 1870 } 1871 1872 } /* end of inner for, scan opcodes */ 1873 1874next_rule:; /* try next rule */ 1875 1876 } /* end of outer for, scan rules */ 1877 printf("+++ ipfw: ouch!, skip past end of rules, denying packet\n"); 1878 return(IP_FW_PORT_DENY_FLAG); 1879 1880done: 1881 /* Update statistics */ 1882 f->pcnt++; 1883 f->bcnt += ip_len; 1884 f->timestamp = time_second; 1885 return retval; 1886 1887pullup_failed: 1888 if (fw_verbose) 1889 printf("pullup failed\n"); 1890 return(IP_FW_PORT_DENY_FLAG); 1891} 1892 1893/* 1894 * When a rule is added/deleted, clear the next_rule pointers in all rules. 1895 * These will be reconstructed on the fly as packets are matched. 1896 * Must be called at splimp(). 1897 */ 1898static void 1899flush_rule_ptrs(void) 1900{ 1901 struct ip_fw *rule; 1902 1903 for (rule = layer3_chain; rule; rule = rule->next) 1904 rule->next_rule = NULL; 1905} 1906 1907/* 1908 * When pipes/queues are deleted, clear the "pipe_ptr" pointer to a given 1909 * pipe/queue, or to all of them (match == NULL). 1910 * Must be called at splimp(). 1911 */ 1912void 1913flush_pipe_ptrs(struct dn_flow_set *match) 1914{ 1915 struct ip_fw *rule; 1916 1917 for (rule = layer3_chain; rule; rule = rule->next) { 1918 ipfw_insn_pipe *cmd = (ipfw_insn_pipe *)ACTION_PTR(rule); 1919 1920 if (cmd->o.opcode != O_PIPE && cmd->o.opcode != O_QUEUE) 1921 continue; 1922 1923 if (match == NULL || cmd->pipe_ptr == match) 1924 cmd->pipe_ptr = NULL; 1925 } 1926} 1927 1928/* 1929 * Add a new rule to the list. Copy the rule into a malloc'ed area, then 1930 * possibly create a rule number and add the rule to the list. 1931 * Update the rule_number in the input struct so the caller knows it as well. 1932 */ 1933static int 1934add_rule(struct ip_fw **head, struct ip_fw *input_rule) 1935{ 1936 struct ip_fw *rule, *f, *prev; 1937 int s; 1938 int l = RULESIZE(input_rule); 1939 1940 if (*head == NULL && input_rule->rulenum != IPFW_DEFAULT_RULE) 1941 return (EINVAL); 1942 1943 rule = malloc(l, M_IPFW, M_DONTWAIT | M_ZERO); 1944 if (rule == NULL) 1945 return (ENOSPC); 1946 1947 bcopy(input_rule, rule, l); 1948 1949 rule->next = NULL; 1950 rule->next_rule = NULL; 1951 1952 rule->pcnt = 0; 1953 rule->bcnt = 0; 1954 rule->timestamp = 0; 1955 1956 s = splimp(); 1957 1958 if (*head == NULL) { /* default rule */ 1959 *head = rule; 1960 goto done; 1961 } 1962 1963 /* 1964 * If rulenum is 0, find highest numbered rule before the 1965 * default rule, and add autoinc_step 1966 */ 1967 if (autoinc_step < 1) 1968 autoinc_step = 1; 1969 else if (autoinc_step > 1000) 1970 autoinc_step = 1000; 1971 if (rule->rulenum == 0) { 1972 /* 1973 * locate the highest numbered rule before default 1974 */ 1975 for (f = *head; f; f = f->next) { 1976 if (f->rulenum == IPFW_DEFAULT_RULE) 1977 break; 1978 rule->rulenum = f->rulenum; 1979 } 1980 if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step) 1981 rule->rulenum += autoinc_step; 1982 input_rule->rulenum = rule->rulenum; 1983 } 1984 1985 /* 1986 * Now insert the new rule in the right place in the sorted list. 1987 */ 1988 for (prev = NULL, f = *head; f; prev = f, f = f->next) { 1989 if (f->rulenum > rule->rulenum) { /* found the location */ 1990 if (prev) { 1991 rule->next = f; 1992 prev->next = rule; 1993 } else { /* head insert */ 1994 rule->next = *head; 1995 *head = rule; 1996 } 1997 break; 1998 } 1999 } 2000 flush_rule_ptrs(); 2001done: 2002 static_count++; 2003 static_len += l; 2004 splx(s); 2005 DEB(printf("++ installed rule %d, static count now %d\n", 2006 rule->rulenum, static_count);) 2007 return (0); 2008} 2009 2010/** 2011 * Free storage associated with a static rule (including derived 2012 * dynamic rules). 2013 * The caller is in charge of clearing rule pointers to avoid 2014 * dangling pointers. 2015 * @return a pointer to the next entry. 2016 * Arguments are not checked, so they better be correct. 2017 * Must be called at splimp(). 2018 */ 2019static struct ip_fw * 2020delete_rule(struct ip_fw **head, struct ip_fw *prev, struct ip_fw *rule) 2021{ 2022 struct ip_fw *n; 2023 int l = RULESIZE(rule); 2024 2025 n = rule->next; 2026 remove_dyn_rule(rule, NULL /* force removal */); 2027 if (prev == NULL) 2028 *head = n; 2029 else 2030 prev->next = n; 2031 static_count--; 2032 static_len -= l; 2033 2034 if (DUMMYNET_LOADED) 2035 ip_dn_ruledel_ptr(rule); 2036 free(rule, M_IPFW); 2037 return n; 2038} 2039 2040/* 2041 * Deletes all rules from a chain (including the default rule 2042 * if the second argument is set). 2043 * Must be called at splimp(). 2044 */ 2045static void 2046free_chain(struct ip_fw **chain, int kill_default) 2047{ 2048 struct ip_fw *rule; 2049 2050 flush_rule_ptrs(); /* more efficient to do outside the loop */ 2051 2052 while ( (rule = *chain) != NULL && 2053 (kill_default || rule->rulenum != IPFW_DEFAULT_RULE) ) 2054 delete_rule(chain, NULL, rule); 2055} 2056 2057/** 2058 * Remove all rules with given number, and also do set manipulation. 2059 * 2060 * The argument is an int. The low 16 bit are the 2061 * rule or set number, the upper 16 bits are the 2062 * function, namely: 2063 * 2064 * 0 DEL_SINGLE_RULE 2065 * 1 DELETE_RULESET 2066 * 2 DISABLE_SET 2067 * 3 ENABLE_SET 2068 */ 2069static int 2070del_entry(struct ip_fw **chain, u_int32_t arg) 2071{ 2072 struct ip_fw *prev, *rule; 2073 int s; 2074 2075 u_int16_t rulenum, cmd; 2076 2077 rulenum = arg & 0xffff; 2078 cmd = (arg >> 16) & 0xffff; 2079 2080 if (cmd > 3) 2081 return EINVAL; 2082 if (cmd == 0 && rulenum == IPFW_DEFAULT_RULE) 2083 return EINVAL; 2084 2085 if (cmd != 0 && rulenum > 30) { 2086 printf("ipfw: del_entry: invalid set number %d\n", 2087 rulenum); 2088 return EINVAL; 2089 } 2090 2091 switch (cmd) { 2092 case 0: /* DEL_SINGLE_RULE */ 2093 /* 2094 * locate first rule to delete 2095 */ 2096 for (prev = NULL, rule = *chain; 2097 rule && rule->rulenum < rulenum; 2098 prev = rule, rule = rule->next) 2099 ; 2100 if (rule->rulenum != rulenum) 2101 return EINVAL; 2102 2103 s = splimp(); /* no access to rules while removing */ 2104 flush_rule_ptrs(); /* more efficient to do outside the loop */ 2105 /* 2106 * prev remains the same throughout the cycle 2107 */ 2108 while (rule && rule->rulenum == rulenum) 2109 rule = delete_rule(chain, prev, rule); 2110 splx(s); 2111 break; 2112 2113 case 1: /* DELETE_RULESET */ 2114 s = splimp(); /* no access to rules while removing */ 2115 flush_rule_ptrs(); /* more efficient to do outside the loop */ 2116 for (prev = NULL, rule = *chain; rule ; ) 2117 if (rule->set == rulenum) 2118 rule = delete_rule(chain, prev, rule); 2119 else { 2120 prev = rule; 2121 rule = rule->next; 2122 } 2123 splx(s); 2124 break; 2125 2126 case 2: /* DISABLE SET */ 2127 s = splimp(); 2128 set_disable |= 1 << rulenum; 2129 splx(s); 2130 break; 2131 2132 case 3: /* ENABLE SET */ 2133 s = splimp(); 2134 set_disable &= ~(1 << rulenum); 2135 splx(s); 2136 break; 2137 } 2138 return 0; 2139} 2140 2141/* 2142 * Clear counters for a specific rule. 2143 */ 2144static void 2145clear_counters(struct ip_fw *rule, int log_only) 2146{ 2147 ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule); 2148 2149 if (log_only == 0) { 2150 rule->bcnt = rule->pcnt = 0; 2151 rule->timestamp = 0; 2152 } 2153 if (l->o.opcode == O_LOG) 2154 l->log_left = l->max_log; 2155} 2156 2157/** 2158 * Reset some or all counters on firewall rules. 2159 * @arg frwl is null to clear all entries, or contains a specific 2160 * rule number. 2161 * @arg log_only is 1 if we only want to reset logs, zero otherwise. 2162 */ 2163static int 2164zero_entry(int rulenum, int log_only) 2165{ 2166 struct ip_fw *rule; 2167 int s; 2168 char *msg; 2169 2170 if (rulenum == 0) { 2171 s = splimp(); 2172 norule_counter = 0; 2173 for (rule = layer3_chain; rule; rule = rule->next) 2174 clear_counters(rule, log_only); 2175 splx(s); 2176 msg = log_only ? "ipfw: All logging counts reset.\n" : 2177 "ipfw: Accounting cleared.\n"; 2178 } else { 2179 int cleared = 0; 2180 /* 2181 * We can have multiple rules with the same number, so we 2182 * need to clear them all. 2183 */ 2184 for (rule = layer3_chain; rule; rule = rule->next) 2185 if (rule->rulenum == rulenum) { 2186 s = splimp(); 2187 while (rule && rule->rulenum == rulenum) { 2188 clear_counters(rule, log_only); 2189 rule = rule->next; 2190 } 2191 splx(s); 2192 cleared = 1; 2193 break; 2194 } 2195 if (!cleared) /* we did not find any matching rules */ 2196 return (EINVAL); 2197 msg = log_only ? "ipfw: Entry %d logging count reset.\n" : 2198 "ipfw: Entry %d cleared.\n"; 2199 } 2200 if (fw_verbose) 2201 log(LOG_SECURITY | LOG_NOTICE, msg, rulenum); 2202 return (0); 2203} 2204 2205/* 2206 * Check validity of the structure before insert. 2207 * Fortunately rules are simple, so this mostly need to check rule sizes. 2208 */ 2209static int 2210check_ipfw_struct(struct ip_fw *rule, int size) 2211{ 2212 int l, cmdlen = 0; 2213 int have_action=0; 2214 ipfw_insn *cmd; 2215 2216 if (size < sizeof(*rule)) { 2217 printf("ipfw: rule too short\n"); 2218 return (EINVAL); 2219 } 2220 /* first, check for valid size */ 2221 l = RULESIZE(rule); 2222 if (l != size) { 2223 printf("ipfw: size mismatch (have %d want %d)\n", size, l); 2224 return (EINVAL); 2225 } 2226 /* 2227 * Now go for the individual checks. Very simple ones, basically only 2228 * instruction sizes. 2229 */ 2230 for (l = rule->cmd_len, cmd = rule->cmd ; 2231 l > 0 ; l -= cmdlen, cmd += cmdlen) { 2232 cmdlen = F_LEN(cmd); 2233 if (cmdlen > l) { 2234 printf("ipfw: opcode %d size truncated\n", 2235 cmd->opcode); 2236 return EINVAL; 2237 } 2238 DEB(printf("ipfw: opcode %d\n", cmd->opcode);) 2239 switch (cmd->opcode) { 2240 case O_NOP: 2241 case O_PROBE_STATE: 2242 case O_KEEP_STATE: 2243 case O_PROTO: 2244 case O_IP_SRC_ME: 2245 case O_IP_DST_ME: 2246 case O_LAYER2: 2247 case O_IN: 2248 case O_FRAG: 2249 case O_IPOPT: 2250 case O_IPLEN: 2251 case O_IPID: 2252 case O_IPTOS: 2253 case O_IPPRECEDENCE: 2254 case O_IPTTL: 2255 case O_IPVER: 2256 case O_TCPWIN: 2257 case O_TCPFLAGS: 2258 case O_TCPOPTS: 2259 case O_ESTAB: 2260 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 2261 goto bad_size; 2262 break; 2263 2264 case O_UID: 2265 case O_GID: 2266 case O_IP_SRC: 2267 case O_IP_DST: 2268 case O_TCPSEQ: 2269 case O_TCPACK: 2270 case O_PROB: 2271 case O_ICMPTYPE: 2272 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 2273 goto bad_size; 2274 break; 2275 2276 case O_LIMIT: 2277 if (cmdlen != F_INSN_SIZE(ipfw_insn_limit)) 2278 goto bad_size; 2279 break; 2280 2281 case O_LOG: 2282 if (cmdlen != F_INSN_SIZE(ipfw_insn_log)) 2283 goto bad_size; 2284 2285 ((ipfw_insn_log *)cmd)->log_left = 2286 ((ipfw_insn_log *)cmd)->max_log; 2287 2288 break; 2289 2290 case O_IP_SRC_MASK: 2291 case O_IP_DST_MASK: 2292 if (cmdlen != F_INSN_SIZE(ipfw_insn_ip)) 2293 goto bad_size; 2294 if (((ipfw_insn_ip *)cmd)->mask.s_addr == 0) { 2295 printf("ipfw: opcode %d, useless rule\n", 2296 cmd->opcode); 2297 return EINVAL; 2298 } 2299 break; 2300 2301 case O_IP_SRC_SET: 2302 case O_IP_DST_SET: 2303 if (cmd->arg1 == 0 || cmd->arg1 > 256) { 2304 printf("ipfw: invalid set size %d\n", 2305 cmd->arg1); 2306 return EINVAL; 2307 } 2308 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 2309 (cmd->arg1+31)/32 ) 2310 goto bad_size; 2311 break; 2312 2313 case O_MACADDR2: 2314 if (cmdlen != F_INSN_SIZE(ipfw_insn_mac)) 2315 goto bad_size; 2316 break; 2317 2318 case O_MAC_TYPE: 2319 case O_IP_SRCPORT: 2320 case O_IP_DSTPORT: /* XXX artificial limit, 15 port pairs */ 2321 if (cmdlen < 2 || cmdlen > 15) 2322 goto bad_size; 2323 break; 2324 2325 case O_RECV: 2326 case O_XMIT: 2327 case O_VIA: 2328 if (cmdlen != F_INSN_SIZE(ipfw_insn_if)) 2329 goto bad_size; 2330 break; 2331 2332 case O_PIPE: 2333 case O_QUEUE: 2334 if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe)) 2335 goto bad_size; 2336 goto check_action; 2337 2338 case O_FORWARD_IP: 2339 if (cmdlen != F_INSN_SIZE(ipfw_insn_sa)) 2340 goto bad_size; 2341 goto check_action; 2342 2343 case O_FORWARD_MAC: /* XXX not implemented yet */ 2344 case O_CHECK_STATE: 2345 case O_COUNT: 2346 case O_ACCEPT: 2347 case O_DENY: 2348 case O_REJECT: 2349 case O_SKIPTO: 2350 case O_DIVERT: 2351 case O_TEE: 2352 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 2353 goto bad_size; 2354check_action: 2355 if (have_action) { 2356 printf("ipfw: opcode %d, multiple actions" 2357 " not allowed\n", 2358 cmd->opcode); 2359 return EINVAL; 2360 } 2361 have_action = 1; 2362 if (l != cmdlen) { 2363 printf("ipfw: opcode %d, action must be" 2364 " last opcode\n", 2365 cmd->opcode); 2366 return EINVAL; 2367 } 2368 break; 2369 default: 2370 printf("ipfw: opcode %d, unknown opcode\n", 2371 cmd->opcode); 2372 return EINVAL; 2373 } 2374 } 2375 if (have_action == 0) { 2376 printf("ipfw: missing action\n"); 2377 return EINVAL; 2378 } 2379 return 0; 2380 2381bad_size: 2382 printf("ipfw: opcode %d size %d wrong\n", 2383 cmd->opcode, cmdlen); 2384 return EINVAL; 2385} 2386 2387 2388/** 2389 * {set|get}sockopt parser. 2390 */ 2391static int 2392ipfw_ctl(struct sockopt *sopt) 2393{ 2394 int error, s, rulenum; 2395 size_t size; 2396 struct ip_fw *bp , *buf, *rule; 2397 2398 static u_int32_t rule_buf[255]; /* we copy the data here */ 2399 2400 /* 2401 * Disallow modifications in really-really secure mode, but still allow 2402 * the logging counters to be reset. 2403 */ 2404 if (sopt->sopt_name == IP_FW_ADD || 2405 (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) { 2406#if __FreeBSD_version >= 500034 2407 error = securelevel_ge(sopt->sopt_td->td_ucred, 3); 2408 if (error) 2409 return (error); 2410#else /* FreeBSD 4.x */ 2411 if (securelevel >= 3) 2412 return (EPERM); 2413#endif 2414 } 2415 2416 error = 0; 2417 2418 switch (sopt->sopt_name) { 2419 case IP_FW_GET: 2420 /* 2421 * pass up a copy of the current rules. Static rules 2422 * come first (the last of which has number IPFW_DEFAULT_RULE), 2423 * followed by a possibly empty list of dynamic rule. 2424 * The last dynamic rule has NULL in the "next" field. 2425 */ 2426 s = splimp(); 2427 size = static_len; /* size of static rules */ 2428 if (ipfw_dyn_v) /* add size of dyn.rules */ 2429 size += (dyn_count * sizeof(ipfw_dyn_rule)); 2430 2431 /* 2432 * XXX todo: if the user passes a short length just to know 2433 * how much room is needed, do not bother filling up the 2434 * buffer, just jump to the sooptcopyout. 2435 */ 2436 buf = malloc(size, M_TEMP, M_WAITOK); 2437 if (buf == 0) { 2438 splx(s); 2439 error = ENOBUFS; 2440 break; 2441 } 2442 2443 bp = buf; 2444 for (rule = layer3_chain; rule ; rule = rule->next) { 2445 int i = RULESIZE(rule); 2446 bcopy(rule, bp, i); 2447 /* 2448 * abuse 'next_rule' to store the set_disable word 2449 */ 2450 (u_int32_t)(((struct ip_fw *)bp)->next_rule) = 2451 set_disable; 2452 bp = (struct ip_fw *)((char *)bp + i); 2453 } 2454 if (ipfw_dyn_v) { 2455 int i; 2456 ipfw_dyn_rule *p, *dst, *last = NULL; 2457 2458 dst = (ipfw_dyn_rule *)bp; 2459 for (i = 0 ; i < curr_dyn_buckets ; i++ ) 2460 for ( p = ipfw_dyn_v[i] ; p != NULL ; 2461 p = p->next, dst++ ) { 2462 bcopy(p, dst, sizeof *p); 2463 (int)dst->rule = p->rule->rulenum ; 2464 /* 2465 * store a non-null value in "next". 2466 * The userland code will interpret a 2467 * NULL here as a marker 2468 * for the last dynamic rule. 2469 */ 2470 dst->next = dst ; 2471 last = dst ; 2472 dst->expire = 2473 TIME_LEQ(dst->expire, time_second) ? 2474 0 : dst->expire - time_second ; 2475 } 2476 if (last != NULL) /* mark last dynamic rule */ 2477 last->next = NULL; 2478 } 2479 splx(s); 2480 2481 error = sooptcopyout(sopt, buf, size); 2482 free(buf, M_TEMP); 2483 break; 2484 2485 case IP_FW_FLUSH: 2486 /* 2487 * Normally we cannot release the lock on each iteration. 2488 * We could do it here only because we start from the head all 2489 * the times so there is no risk of missing some entries. 2490 * On the other hand, the risk is that we end up with 2491 * a very inconsistent ruleset, so better keep the lock 2492 * around the whole cycle. 2493 * 2494 * XXX this code can be improved by resetting the head of 2495 * the list to point to the default rule, and then freeing 2496 * the old list without the need for a lock. 2497 */ 2498 2499 s = splimp(); 2500 free_chain(&layer3_chain, 0 /* keep default rule */); 2501 splx(s); 2502 break; 2503 2504 case IP_FW_ADD: 2505 rule = (struct ip_fw *)rule_buf; /* XXX do a malloc */ 2506 error = sooptcopyin(sopt, rule, sizeof(rule_buf), 2507 sizeof(struct ip_fw) ); 2508 size = sopt->sopt_valsize; 2509 if (error || (error = check_ipfw_struct(rule, size))) 2510 break; 2511 2512 error = add_rule(&layer3_chain, rule); 2513 size = RULESIZE(rule); 2514 if (!error && sopt->sopt_dir == SOPT_GET) 2515 error = sooptcopyout(sopt, rule, size); 2516 break; 2517 2518 case IP_FW_DEL: /* argument is an int, the rule number */ 2519 /* 2520 * IP_FW_DEL is used for deleting single rules, 2521 * set of rules, and manipulating set_disable. 2522 * 2523 * Everything is managed in del_entry(); 2524 */ 2525 error = sooptcopyin(sopt, &rulenum, sizeof(int), sizeof(int)); 2526 if (error) 2527 break; 2528 if (rulenum == IPFW_DEFAULT_RULE) { 2529 if (fw_debug) 2530 printf("ipfw: can't delete rule %u\n", 2531 (unsigned)IPFW_DEFAULT_RULE); 2532 error = EINVAL; 2533 } else 2534 error = del_entry(&layer3_chain, rulenum); 2535 break; 2536 2537 case IP_FW_ZERO: 2538 case IP_FW_RESETLOG: /* argument is an int, the rule number */ 2539 rulenum=0; 2540 2541 if (sopt->sopt_val != 0) { 2542 error = sooptcopyin(sopt, &rulenum, 2543 sizeof(int), sizeof(int)); 2544 if (error) 2545 break; 2546 } 2547 error = zero_entry(rulenum, sopt->sopt_name == IP_FW_RESETLOG); 2548 break; 2549 2550 default: 2551 printf("ipfw_ctl invalid option %d\n", sopt->sopt_name); 2552 error = EINVAL; 2553 } 2554 2555 return (error); 2556} 2557 2558/** 2559 * dummynet needs a reference to the default rule, because rules can be 2560 * deleted while packets hold a reference to them. When this happens, 2561 * dummynet changes the reference to the default rule (it could well be a 2562 * NULL pointer, but this way we do not need to check for the special 2563 * case, plus here he have info on the default behaviour). 2564 */ 2565struct ip_fw *ip_fw_default_rule; 2566 2567static void 2568ipfw_tick(void * __unused unused) 2569{ 2570 int i; 2571 int s; 2572 ipfw_dyn_rule *q; 2573 2574 if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0) 2575 goto done; 2576 2577 s = splimp(); 2578 for (i = 0 ; i < curr_dyn_buckets ; i++) { 2579 for (q = ipfw_dyn_v[i] ; q ; q = q->next ) { 2580 if (q->dyn_type == O_LIMIT_PARENT) 2581 continue; 2582 if (q->id.proto != IPPROTO_TCP) 2583 continue; 2584 if ( (q->state & BOTH_SYN) != BOTH_SYN) 2585 continue; 2586 if (TIME_LEQ( time_second+20, q->expire)) 2587 continue; /* too early */ 2588 if (TIME_LEQ(q->expire, time_second)) 2589 continue; /* too late, rule expired */ 2590 2591 send_pkt(&(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 2592 send_pkt(&(q->id), q->ack_fwd - 1, q->ack_rev, 0); 2593 } 2594 } 2595 splx(s); 2596done: 2597 ipfw_timeout_h = timeout(ipfw_tick, NULL, 5*hz); 2598} 2599 2600static void 2601ipfw_init(void) 2602{ 2603 struct ip_fw default_rule; 2604 2605 ip_fw_chk_ptr = ipfw_chk; 2606 ip_fw_ctl_ptr = ipfw_ctl; 2607 layer3_chain = NULL; 2608 2609 bzero(&default_rule, sizeof default_rule); 2610 2611 default_rule.act_ofs = 0; 2612 default_rule.rulenum = IPFW_DEFAULT_RULE; 2613 default_rule.cmd_len = 1; 2614 default_rule.set = 31; 2615 2616 default_rule.cmd[0].len = 1; 2617 default_rule.cmd[0].opcode = 2618#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 2619 1 ? O_ACCEPT : 2620#endif 2621 O_DENY; 2622 2623 add_rule(&layer3_chain, &default_rule); 2624 2625 ip_fw_default_rule = layer3_chain; 2626 printf("IP packet filtering initialized, divert %s, " 2627 "rule-based forwarding %s, default to %s, logging ", 2628#ifdef IPDIVERT 2629 "enabled", 2630#else 2631 "disabled", 2632#endif 2633 "enabled", 2634 default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny"); 2635 2636#ifdef IPFIREWALL_VERBOSE 2637 fw_verbose = 1; 2638#endif 2639#ifdef IPFIREWALL_VERBOSE_LIMIT 2640 verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 2641#endif 2642 printf("logging "); 2643 if (fw_verbose == 0) 2644 printf("disabled\n"); 2645 else if (verbose_limit == 0) 2646 printf("unlimited\n"); 2647 else 2648 printf("limited to %d packets/entry by default\n", 2649 verbose_limit); 2650 bzero(&ipfw_timeout_h, sizeof(struct callout_handle)); 2651 ipfw_timeout_h = timeout(ipfw_tick, NULL, hz); 2652} 2653 2654static int 2655ipfw_modevent(module_t mod, int type, void *unused) 2656{ 2657 int s; 2658 int err = 0; 2659 2660 switch (type) { 2661 case MOD_LOAD: 2662 s = splimp(); 2663 if (IPFW_LOADED) { 2664 splx(s); 2665 printf("IP firewall already loaded\n"); 2666 err = EEXIST; 2667 } else { 2668 ipfw_init(); 2669 splx(s); 2670 } 2671 break; 2672 2673 case MOD_UNLOAD: 2674#if !defined(KLD_MODULE) 2675 printf("ipfw statically compiled, cannot unload\n"); 2676 err = EBUSY; 2677#else 2678 s = splimp(); 2679 untimeout(ipfw_tick, NULL, ipfw_timeout_h); 2680 ip_fw_chk_ptr = NULL; 2681 ip_fw_ctl_ptr = NULL; 2682 free_chain(&layer3_chain, 1 /* kill default rule */); 2683 splx(s); 2684 printf("IP firewall unloaded\n"); 2685#endif 2686 break; 2687 default: 2688 break; 2689 } 2690 return err; 2691} 2692 2693static moduledata_t ipfwmod = { 2694 "ipfw", 2695 ipfw_modevent, 2696 0 2697}; 2698DECLARE_MODULE(ipfw, ipfwmod, SI_SUB_PSEUDO, SI_ORDER_ANY); 2699MODULE_VERSION(ipfw, 1); 2700#endif /* IPFW2 */ 2701