ip_fw2.c revision 134022
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 134022 2004-08-19 17:38:47Z andre $ 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#include "opt_ipsec.h" 41#ifndef INET 42#error IPFIREWALL requires INET. 43#endif /* INET */ 44#endif 45 46#define IPFW2 1 47#if IPFW2 48#include <sys/param.h> 49#include <sys/systm.h> 50#include <sys/malloc.h> 51#include <sys/mbuf.h> 52#include <sys/kernel.h> 53#include <sys/jail.h> 54#include <sys/module.h> 55#include <sys/proc.h> 56#include <sys/socket.h> 57#include <sys/socketvar.h> 58#include <sys/sysctl.h> 59#include <sys/syslog.h> 60#include <sys/ucred.h> 61#include <net/if.h> 62#include <net/radix.h> 63#include <net/route.h> 64#include <netinet/in.h> 65#include <netinet/in_systm.h> 66#include <netinet/in_var.h> 67#include <netinet/in_pcb.h> 68#include <netinet/ip.h> 69#include <netinet/ip_var.h> 70#include <netinet/ip_icmp.h> 71#include <netinet/ip_fw.h> 72#include <netinet/ip_divert.h> 73#include <netinet/ip_dummynet.h> 74#include <netinet/tcp.h> 75#include <netinet/tcp_timer.h> 76#include <netinet/tcp_var.h> 77#include <netinet/tcpip.h> 78#include <netinet/udp.h> 79#include <netinet/udp_var.h> 80 81#ifdef IPSEC 82#include <netinet6/ipsec.h> 83#endif 84 85#include <netinet/if_ether.h> /* XXX for ETHERTYPE_IP */ 86 87#include <machine/in_cksum.h> /* XXX for in_cksum */ 88 89/* 90 * set_disable contains one bit per set value (0..31). 91 * If the bit is set, all rules with the corresponding set 92 * are disabled. Set RESVD_SET(31) is reserved for the default rule 93 * and rules that are not deleted by the flush command, 94 * and CANNOT be disabled. 95 * Rules in set RESVD_SET can only be deleted explicitly. 96 */ 97static u_int32_t set_disable; 98 99static int fw_verbose; 100static int verbose_limit; 101 102static struct callout ipfw_timeout; 103#define IPFW_DEFAULT_RULE 65535 104 105/* 106 * Data structure to cache our ucred related 107 * information. This structure only gets used if 108 * the user specified UID/GID based constraints in 109 * a firewall rule. 110 */ 111struct ip_fw_ugid { 112 gid_t fw_groups[NGROUPS]; 113 int fw_ngroups; 114 uid_t fw_uid; 115 int fw_prid; 116}; 117 118struct ip_fw_chain { 119 struct ip_fw *rules; /* list of rules */ 120 struct ip_fw *reap; /* list of rules to reap */ 121 struct mtx mtx; /* lock guarding rule list */ 122}; 123#define IPFW_LOCK_INIT(_chain) \ 124 mtx_init(&(_chain)->mtx, "IPFW static rules", NULL, \ 125 MTX_DEF | MTX_RECURSE) 126#define IPFW_LOCK_DESTROY(_chain) mtx_destroy(&(_chain)->mtx) 127#define IPFW_LOCK(_chain) mtx_lock(&(_chain)->mtx) 128#define IPFW_UNLOCK(_chain) mtx_unlock(&(_chain)->mtx) 129#define IPFW_LOCK_ASSERT(_chain) do { \ 130 mtx_assert(&(_chain)->mtx, MA_OWNED); \ 131 NET_ASSERT_GIANT(); \ 132} while (0) 133 134/* 135 * list of rules for layer 3 136 */ 137static struct ip_fw_chain layer3_chain; 138 139MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's"); 140MALLOC_DEFINE(M_IPFW_TBL, "ipfw_tbl", "IpFw tables"); 141 142struct table_entry { 143 struct radix_node rn[2]; 144 struct sockaddr_in addr, mask; 145 u_int32_t value; 146}; 147 148#define IPFW_TABLES_MAX 128 149static struct { 150 struct radix_node_head *rnh; 151 int modified; 152} ipfw_tables[IPFW_TABLES_MAX]; 153 154static int fw_debug = 1; 155static int autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 156 157#ifdef SYSCTL_NODE 158SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 159SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, 160 CTLFLAG_RW | CTLFLAG_SECURE3, 161 &fw_enable, 0, "Enable ipfw"); 162SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, CTLFLAG_RW, 163 &autoinc_step, 0, "Rule number autincrement step"); 164SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 165 CTLFLAG_RW | CTLFLAG_SECURE3, 166 &fw_one_pass, 0, 167 "Only do a single pass through ipfw when using dummynet(4)"); 168SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW, 169 &fw_debug, 0, "Enable printing of debug ip_fw statements"); 170SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, 171 CTLFLAG_RW | CTLFLAG_SECURE3, 172 &fw_verbose, 0, "Log matches to ipfw rules"); 173SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, 174 &verbose_limit, 0, "Set upper limit of matches of ipfw rules logged"); 175 176/* 177 * Description of dynamic rules. 178 * 179 * Dynamic rules are stored in lists accessed through a hash table 180 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 181 * be modified through the sysctl variable dyn_buckets which is 182 * updated when the table becomes empty. 183 * 184 * XXX currently there is only one list, ipfw_dyn. 185 * 186 * When a packet is received, its address fields are first masked 187 * with the mask defined for the rule, then hashed, then matched 188 * against the entries in the corresponding list. 189 * Dynamic rules can be used for different purposes: 190 * + stateful rules; 191 * + enforcing limits on the number of sessions; 192 * + in-kernel NAT (not implemented yet) 193 * 194 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 195 * measured in seconds and depending on the flags. 196 * 197 * The total number of dynamic rules is stored in dyn_count. 198 * The max number of dynamic rules is dyn_max. When we reach 199 * the maximum number of rules we do not create anymore. This is 200 * done to avoid consuming too much memory, but also too much 201 * time when searching on each packet (ideally, we should try instead 202 * to put a limit on the length of the list on each bucket...). 203 * 204 * Each dynamic rule holds a pointer to the parent ipfw rule so 205 * we know what action to perform. Dynamic rules are removed when 206 * the parent rule is deleted. XXX we should make them survive. 207 * 208 * There are some limitations with dynamic rules -- we do not 209 * obey the 'randomized match', and we do not do multiple 210 * passes through the firewall. XXX check the latter!!! 211 */ 212static ipfw_dyn_rule **ipfw_dyn_v = NULL; 213static u_int32_t dyn_buckets = 256; /* must be power of 2 */ 214static u_int32_t curr_dyn_buckets = 256; /* must be power of 2 */ 215 216static struct mtx ipfw_dyn_mtx; /* mutex guarding dynamic rules */ 217#define IPFW_DYN_LOCK_INIT() \ 218 mtx_init(&ipfw_dyn_mtx, "IPFW dynamic rules", NULL, MTX_DEF) 219#define IPFW_DYN_LOCK_DESTROY() mtx_destroy(&ipfw_dyn_mtx) 220#define IPFW_DYN_LOCK() mtx_lock(&ipfw_dyn_mtx) 221#define IPFW_DYN_UNLOCK() mtx_unlock(&ipfw_dyn_mtx) 222#define IPFW_DYN_LOCK_ASSERT() mtx_assert(&ipfw_dyn_mtx, MA_OWNED) 223 224/* 225 * Timeouts for various events in handing dynamic rules. 226 */ 227static u_int32_t dyn_ack_lifetime = 300; 228static u_int32_t dyn_syn_lifetime = 20; 229static u_int32_t dyn_fin_lifetime = 1; 230static u_int32_t dyn_rst_lifetime = 1; 231static u_int32_t dyn_udp_lifetime = 10; 232static u_int32_t dyn_short_lifetime = 5; 233 234/* 235 * Keepalives are sent if dyn_keepalive is set. They are sent every 236 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 237 * seconds of lifetime of a rule. 238 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 239 * than dyn_keepalive_period. 240 */ 241 242static u_int32_t dyn_keepalive_interval = 20; 243static u_int32_t dyn_keepalive_period = 5; 244static u_int32_t dyn_keepalive = 1; /* do send keepalives */ 245 246static u_int32_t static_count; /* # of static rules */ 247static u_int32_t static_len; /* size in bytes of static rules */ 248static u_int32_t dyn_count; /* # of dynamic rules */ 249static u_int32_t dyn_max = 4096; /* max # of dynamic rules */ 250 251SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW, 252 &dyn_buckets, 0, "Number of dyn. buckets"); 253SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD, 254 &curr_dyn_buckets, 0, "Current Number of dyn. buckets"); 255SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD, 256 &dyn_count, 0, "Number of dyn. rules"); 257SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW, 258 &dyn_max, 0, "Max number of dyn. rules"); 259SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD, 260 &static_count, 0, "Number of static rules"); 261SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW, 262 &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks"); 263SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW, 264 &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn"); 265SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW, 266 &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin"); 267SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW, 268 &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst"); 269SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW, 270 &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP"); 271SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW, 272 &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations"); 273SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, CTLFLAG_RW, 274 &dyn_keepalive, 0, "Enable keepalives for dyn. rules"); 275 276#endif /* SYSCTL_NODE */ 277 278 279/* 280 * This macro maps an ip pointer into a layer3 header pointer of type T 281 */ 282#define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 283 284static __inline int 285icmptype_match(struct ip *ip, ipfw_insn_u32 *cmd) 286{ 287 int type = L3HDR(struct icmp,ip)->icmp_type; 288 289 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 290} 291 292#define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 293 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 294 295static int 296is_icmp_query(struct ip *ip) 297{ 298 int type = L3HDR(struct icmp, ip)->icmp_type; 299 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 300} 301#undef TT 302 303/* 304 * The following checks use two arrays of 8 or 16 bits to store the 305 * bits that we want set or clear, respectively. They are in the 306 * low and high half of cmd->arg1 or cmd->d[0]. 307 * 308 * We scan options and store the bits we find set. We succeed if 309 * 310 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 311 * 312 * The code is sometimes optimized not to store additional variables. 313 */ 314 315static int 316flags_match(ipfw_insn *cmd, u_int8_t bits) 317{ 318 u_char want_clear; 319 bits = ~bits; 320 321 if ( ((cmd->arg1 & 0xff) & bits) != 0) 322 return 0; /* some bits we want set were clear */ 323 want_clear = (cmd->arg1 >> 8) & 0xff; 324 if ( (want_clear & bits) != want_clear) 325 return 0; /* some bits we want clear were set */ 326 return 1; 327} 328 329static int 330ipopts_match(struct ip *ip, ipfw_insn *cmd) 331{ 332 int optlen, bits = 0; 333 u_char *cp = (u_char *)(ip + 1); 334 int x = (ip->ip_hl << 2) - sizeof (struct ip); 335 336 for (; x > 0; x -= optlen, cp += optlen) { 337 int opt = cp[IPOPT_OPTVAL]; 338 339 if (opt == IPOPT_EOL) 340 break; 341 if (opt == IPOPT_NOP) 342 optlen = 1; 343 else { 344 optlen = cp[IPOPT_OLEN]; 345 if (optlen <= 0 || optlen > x) 346 return 0; /* invalid or truncated */ 347 } 348 switch (opt) { 349 350 default: 351 break; 352 353 case IPOPT_LSRR: 354 bits |= IP_FW_IPOPT_LSRR; 355 break; 356 357 case IPOPT_SSRR: 358 bits |= IP_FW_IPOPT_SSRR; 359 break; 360 361 case IPOPT_RR: 362 bits |= IP_FW_IPOPT_RR; 363 break; 364 365 case IPOPT_TS: 366 bits |= IP_FW_IPOPT_TS; 367 break; 368 } 369 } 370 return (flags_match(cmd, bits)); 371} 372 373static int 374tcpopts_match(struct ip *ip, ipfw_insn *cmd) 375{ 376 int optlen, bits = 0; 377 struct tcphdr *tcp = L3HDR(struct tcphdr,ip); 378 u_char *cp = (u_char *)(tcp + 1); 379 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 380 381 for (; x > 0; x -= optlen, cp += optlen) { 382 int opt = cp[0]; 383 if (opt == TCPOPT_EOL) 384 break; 385 if (opt == TCPOPT_NOP) 386 optlen = 1; 387 else { 388 optlen = cp[1]; 389 if (optlen <= 0) 390 break; 391 } 392 393 switch (opt) { 394 395 default: 396 break; 397 398 case TCPOPT_MAXSEG: 399 bits |= IP_FW_TCPOPT_MSS; 400 break; 401 402 case TCPOPT_WINDOW: 403 bits |= IP_FW_TCPOPT_WINDOW; 404 break; 405 406 case TCPOPT_SACK_PERMITTED: 407 case TCPOPT_SACK: 408 bits |= IP_FW_TCPOPT_SACK; 409 break; 410 411 case TCPOPT_TIMESTAMP: 412 bits |= IP_FW_TCPOPT_TS; 413 break; 414 415 case TCPOPT_CC: 416 case TCPOPT_CCNEW: 417 case TCPOPT_CCECHO: 418 bits |= IP_FW_TCPOPT_CC; 419 break; 420 } 421 } 422 return (flags_match(cmd, bits)); 423} 424 425static int 426iface_match(struct ifnet *ifp, ipfw_insn_if *cmd) 427{ 428 if (ifp == NULL) /* no iface with this packet, match fails */ 429 return 0; 430 /* Check by name or by IP address */ 431 if (cmd->name[0] != '\0') { /* match by name */ 432 /* Check name */ 433 if (cmd->p.glob) { 434 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 435 return(1); 436 } else { 437 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 438 return(1); 439 } 440 } else { 441 struct ifaddr *ia; 442 443 /* XXX lock? */ 444 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 445 if (ia->ifa_addr == NULL) 446 continue; 447 if (ia->ifa_addr->sa_family != AF_INET) 448 continue; 449 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 450 (ia->ifa_addr))->sin_addr.s_addr) 451 return(1); /* match */ 452 } 453 } 454 return(0); /* no match, fail ... */ 455} 456 457/* 458 * The verify_path function checks if a route to the src exists and 459 * if it is reachable via ifp (when provided). 460 * 461 * The 'verrevpath' option checks that the interface that an IP packet 462 * arrives on is the same interface that traffic destined for the 463 * packet's source address would be routed out of. The 'versrcreach' 464 * option just checks that the source address is reachable via any route 465 * (except default) in the routing table. These two are a measure to block 466 * forged packets. This is also commonly known as "anti-spoofing" or Unicast 467 * Reverse Path Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 468 * is purposely reminiscent of the Cisco IOS command, 469 * 470 * ip verify unicast reverse-path 471 * ip verify unicast source reachable-via any 472 * 473 * which implements the same functionality. But note that syntax is 474 * misleading. The check may be performed on all IP packets whether unicast, 475 * multicast, or broadcast. 476 */ 477static int 478verify_path(struct in_addr src, struct ifnet *ifp) 479{ 480 struct route ro; 481 struct sockaddr_in *dst; 482 483 bzero(&ro, sizeof(ro)); 484 485 dst = (struct sockaddr_in *)&(ro.ro_dst); 486 dst->sin_family = AF_INET; 487 dst->sin_len = sizeof(*dst); 488 dst->sin_addr = src; 489 rtalloc_ign(&ro, RTF_CLONING); 490 491 if (ro.ro_rt == NULL) 492 return 0; 493 494 /* if ifp is provided, check for equality with rtentry */ 495 if (ifp != NULL && ro.ro_rt->rt_ifp != ifp) { 496 RTFREE(ro.ro_rt); 497 return 0; 498 } 499 500 /* if no ifp provided, check if rtentry is not default route */ 501 if (ifp == NULL && 502 satosin(rt_key(ro.ro_rt))->sin_addr.s_addr == INADDR_ANY) { 503 RTFREE(ro.ro_rt); 504 return 0; 505 } 506 507 /* or if this is a blackhole/reject route */ 508 if (ifp == NULL && ro.ro_rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 509 RTFREE(ro.ro_rt); 510 return 0; 511 } 512 513 /* found valid route */ 514 RTFREE(ro.ro_rt); 515 return 1; 516} 517 518 519static u_int64_t norule_counter; /* counter for ipfw_log(NULL...) */ 520 521#define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0 522#define SNP(buf) buf, sizeof(buf) 523 524/* 525 * We enter here when we have a rule with O_LOG. 526 * XXX this function alone takes about 2Kbytes of code! 527 */ 528static void 529ipfw_log(struct ip_fw *f, u_int hlen, struct ether_header *eh, 530 struct mbuf *m, struct ifnet *oif) 531{ 532 char *action; 533 int limit_reached = 0; 534 char action2[40], proto[48], fragment[28]; 535 536 fragment[0] = '\0'; 537 proto[0] = '\0'; 538 539 if (f == NULL) { /* bogus pkt */ 540 if (verbose_limit != 0 && norule_counter >= verbose_limit) 541 return; 542 norule_counter++; 543 if (norule_counter == verbose_limit) 544 limit_reached = verbose_limit; 545 action = "Refuse"; 546 } else { /* O_LOG is the first action, find the real one */ 547 ipfw_insn *cmd = ACTION_PTR(f); 548 ipfw_insn_log *l = (ipfw_insn_log *)cmd; 549 550 if (l->max_log != 0 && l->log_left == 0) 551 return; 552 l->log_left--; 553 if (l->log_left == 0) 554 limit_reached = l->max_log; 555 cmd += F_LEN(cmd); /* point to first action */ 556 if (cmd->opcode == O_PROB) 557 cmd += F_LEN(cmd); 558 559 action = action2; 560 switch (cmd->opcode) { 561 case O_DENY: 562 action = "Deny"; 563 break; 564 565 case O_REJECT: 566 if (cmd->arg1==ICMP_REJECT_RST) 567 action = "Reset"; 568 else if (cmd->arg1==ICMP_UNREACH_HOST) 569 action = "Reject"; 570 else 571 snprintf(SNPARGS(action2, 0), "Unreach %d", 572 cmd->arg1); 573 break; 574 575 case O_ACCEPT: 576 action = "Accept"; 577 break; 578 case O_COUNT: 579 action = "Count"; 580 break; 581 case O_DIVERT: 582 snprintf(SNPARGS(action2, 0), "Divert %d", 583 cmd->arg1); 584 break; 585 case O_TEE: 586 snprintf(SNPARGS(action2, 0), "Tee %d", 587 cmd->arg1); 588 break; 589 case O_SKIPTO: 590 snprintf(SNPARGS(action2, 0), "SkipTo %d", 591 cmd->arg1); 592 break; 593 case O_PIPE: 594 snprintf(SNPARGS(action2, 0), "Pipe %d", 595 cmd->arg1); 596 break; 597 case O_QUEUE: 598 snprintf(SNPARGS(action2, 0), "Queue %d", 599 cmd->arg1); 600 break; 601 case O_FORWARD_IP: { 602 ipfw_insn_sa *sa = (ipfw_insn_sa *)cmd; 603 int len; 604 605 len = snprintf(SNPARGS(action2, 0), "Forward to %s", 606 inet_ntoa(sa->sa.sin_addr)); 607 if (sa->sa.sin_port) 608 snprintf(SNPARGS(action2, len), ":%d", 609 sa->sa.sin_port); 610 } 611 break; 612 default: 613 action = "UNKNOWN"; 614 break; 615 } 616 } 617 618 if (hlen == 0) { /* non-ip */ 619 snprintf(SNPARGS(proto, 0), "MAC"); 620 } else { 621 struct ip *ip = mtod(m, struct ip *); 622 /* these three are all aliases to the same thing */ 623 struct icmp *const icmp = L3HDR(struct icmp, ip); 624 struct tcphdr *const tcp = (struct tcphdr *)icmp; 625 struct udphdr *const udp = (struct udphdr *)icmp; 626 627 int ip_off, offset, ip_len; 628 629 int len; 630 631 if (eh != NULL) { /* layer 2 packets are as on the wire */ 632 ip_off = ntohs(ip->ip_off); 633 ip_len = ntohs(ip->ip_len); 634 } else { 635 ip_off = ip->ip_off; 636 ip_len = ip->ip_len; 637 } 638 offset = ip_off & IP_OFFMASK; 639 switch (ip->ip_p) { 640 case IPPROTO_TCP: 641 len = snprintf(SNPARGS(proto, 0), "TCP %s", 642 inet_ntoa(ip->ip_src)); 643 if (offset == 0) 644 snprintf(SNPARGS(proto, len), ":%d %s:%d", 645 ntohs(tcp->th_sport), 646 inet_ntoa(ip->ip_dst), 647 ntohs(tcp->th_dport)); 648 else 649 snprintf(SNPARGS(proto, len), " %s", 650 inet_ntoa(ip->ip_dst)); 651 break; 652 653 case IPPROTO_UDP: 654 len = snprintf(SNPARGS(proto, 0), "UDP %s", 655 inet_ntoa(ip->ip_src)); 656 if (offset == 0) 657 snprintf(SNPARGS(proto, len), ":%d %s:%d", 658 ntohs(udp->uh_sport), 659 inet_ntoa(ip->ip_dst), 660 ntohs(udp->uh_dport)); 661 else 662 snprintf(SNPARGS(proto, len), " %s", 663 inet_ntoa(ip->ip_dst)); 664 break; 665 666 case IPPROTO_ICMP: 667 if (offset == 0) 668 len = snprintf(SNPARGS(proto, 0), 669 "ICMP:%u.%u ", 670 icmp->icmp_type, icmp->icmp_code); 671 else 672 len = snprintf(SNPARGS(proto, 0), "ICMP "); 673 len += snprintf(SNPARGS(proto, len), "%s", 674 inet_ntoa(ip->ip_src)); 675 snprintf(SNPARGS(proto, len), " %s", 676 inet_ntoa(ip->ip_dst)); 677 break; 678 679 default: 680 len = snprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p, 681 inet_ntoa(ip->ip_src)); 682 snprintf(SNPARGS(proto, len), " %s", 683 inet_ntoa(ip->ip_dst)); 684 break; 685 } 686 687 if (ip_off & (IP_MF | IP_OFFMASK)) 688 snprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)", 689 ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2), 690 offset << 3, 691 (ip_off & IP_MF) ? "+" : ""); 692 } 693 if (oif || m->m_pkthdr.rcvif) 694 log(LOG_SECURITY | LOG_INFO, 695 "ipfw: %d %s %s %s via %s%s\n", 696 f ? f->rulenum : -1, 697 action, proto, oif ? "out" : "in", 698 oif ? oif->if_xname : m->m_pkthdr.rcvif->if_xname, 699 fragment); 700 else 701 log(LOG_SECURITY | LOG_INFO, 702 "ipfw: %d %s %s [no if info]%s\n", 703 f ? f->rulenum : -1, 704 action, proto, fragment); 705 if (limit_reached) 706 log(LOG_SECURITY | LOG_NOTICE, 707 "ipfw: limit %d reached on entry %d\n", 708 limit_reached, f ? f->rulenum : -1); 709} 710 711/* 712 * IMPORTANT: the hash function for dynamic rules must be commutative 713 * in source and destination (ip,port), because rules are bidirectional 714 * and we want to find both in the same bucket. 715 */ 716static __inline int 717hash_packet(struct ipfw_flow_id *id) 718{ 719 u_int32_t i; 720 721 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 722 i &= (curr_dyn_buckets - 1); 723 return i; 724} 725 726/** 727 * unlink a dynamic rule from a chain. prev is a pointer to 728 * the previous one, q is a pointer to the rule to delete, 729 * head is a pointer to the head of the queue. 730 * Modifies q and potentially also head. 731 */ 732#define UNLINK_DYN_RULE(prev, head, q) { \ 733 ipfw_dyn_rule *old_q = q; \ 734 \ 735 /* remove a refcount to the parent */ \ 736 if (q->dyn_type == O_LIMIT) \ 737 q->parent->count--; \ 738 DEB(printf("ipfw: unlink entry 0x%08x %d -> 0x%08x %d, %d left\n",\ 739 (q->id.src_ip), (q->id.src_port), \ 740 (q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \ 741 if (prev != NULL) \ 742 prev->next = q = q->next; \ 743 else \ 744 head = q = q->next; \ 745 dyn_count--; \ 746 free(old_q, M_IPFW); } 747 748#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 749 750/** 751 * Remove dynamic rules pointing to "rule", or all of them if rule == NULL. 752 * 753 * If keep_me == NULL, rules are deleted even if not expired, 754 * otherwise only expired rules are removed. 755 * 756 * The value of the second parameter is also used to point to identify 757 * a rule we absolutely do not want to remove (e.g. because we are 758 * holding a reference to it -- this is the case with O_LIMIT_PARENT 759 * rules). The pointer is only used for comparison, so any non-null 760 * value will do. 761 */ 762static void 763remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me) 764{ 765 static u_int32_t last_remove = 0; 766 767#define FORCE (keep_me == NULL) 768 769 ipfw_dyn_rule *prev, *q; 770 int i, pass = 0, max_pass = 0; 771 772 IPFW_DYN_LOCK_ASSERT(); 773 774 if (ipfw_dyn_v == NULL || dyn_count == 0) 775 return; 776 /* do not expire more than once per second, it is useless */ 777 if (!FORCE && last_remove == time_second) 778 return; 779 last_remove = time_second; 780 781 /* 782 * because O_LIMIT refer to parent rules, during the first pass only 783 * remove child and mark any pending LIMIT_PARENT, and remove 784 * them in a second pass. 785 */ 786next_pass: 787 for (i = 0 ; i < curr_dyn_buckets ; i++) { 788 for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) { 789 /* 790 * Logic can become complex here, so we split tests. 791 */ 792 if (q == keep_me) 793 goto next; 794 if (rule != NULL && rule != q->rule) 795 goto next; /* not the one we are looking for */ 796 if (q->dyn_type == O_LIMIT_PARENT) { 797 /* 798 * handle parent in the second pass, 799 * record we need one. 800 */ 801 max_pass = 1; 802 if (pass == 0) 803 goto next; 804 if (FORCE && q->count != 0 ) { 805 /* XXX should not happen! */ 806 printf("ipfw: OUCH! cannot remove rule," 807 " count %d\n", q->count); 808 } 809 } else { 810 if (!FORCE && 811 !TIME_LEQ( q->expire, time_second )) 812 goto next; 813 } 814 if (q->dyn_type != O_LIMIT_PARENT || !q->count) { 815 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 816 continue; 817 } 818next: 819 prev=q; 820 q=q->next; 821 } 822 } 823 if (pass++ < max_pass) 824 goto next_pass; 825} 826 827 828/** 829 * lookup a dynamic rule. 830 */ 831static ipfw_dyn_rule * 832lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int *match_direction, 833 struct tcphdr *tcp) 834{ 835 /* 836 * stateful ipfw extensions. 837 * Lookup into dynamic session queue 838 */ 839#define MATCH_REVERSE 0 840#define MATCH_FORWARD 1 841#define MATCH_NONE 2 842#define MATCH_UNKNOWN 3 843 int i, dir = MATCH_NONE; 844 ipfw_dyn_rule *prev, *q=NULL; 845 846 IPFW_DYN_LOCK_ASSERT(); 847 848 if (ipfw_dyn_v == NULL) 849 goto done; /* not found */ 850 i = hash_packet( pkt ); 851 for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) { 852 if (q->dyn_type == O_LIMIT_PARENT && q->count) 853 goto next; 854 if (TIME_LEQ( q->expire, time_second)) { /* expire entry */ 855 UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q); 856 continue; 857 } 858 if (pkt->proto == q->id.proto && 859 q->dyn_type != O_LIMIT_PARENT) { 860 if (pkt->src_ip == q->id.src_ip && 861 pkt->dst_ip == q->id.dst_ip && 862 pkt->src_port == q->id.src_port && 863 pkt->dst_port == q->id.dst_port ) { 864 dir = MATCH_FORWARD; 865 break; 866 } 867 if (pkt->src_ip == q->id.dst_ip && 868 pkt->dst_ip == q->id.src_ip && 869 pkt->src_port == q->id.dst_port && 870 pkt->dst_port == q->id.src_port ) { 871 dir = MATCH_REVERSE; 872 break; 873 } 874 } 875next: 876 prev = q; 877 q = q->next; 878 } 879 if (q == NULL) 880 goto done; /* q = NULL, not found */ 881 882 if ( prev != NULL) { /* found and not in front */ 883 prev->next = q->next; 884 q->next = ipfw_dyn_v[i]; 885 ipfw_dyn_v[i] = q; 886 } 887 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 888 u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST); 889 890#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 891#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 892 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8); 893 switch (q->state) { 894 case TH_SYN: /* opening */ 895 q->expire = time_second + dyn_syn_lifetime; 896 break; 897 898 case BOTH_SYN: /* move to established */ 899 case BOTH_SYN | TH_FIN : /* one side tries to close */ 900 case BOTH_SYN | (TH_FIN << 8) : 901 if (tcp) { 902#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 903 u_int32_t ack = ntohl(tcp->th_ack); 904 if (dir == MATCH_FORWARD) { 905 if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd)) 906 q->ack_fwd = ack; 907 else { /* ignore out-of-sequence */ 908 break; 909 } 910 } else { 911 if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev)) 912 q->ack_rev = ack; 913 else { /* ignore out-of-sequence */ 914 break; 915 } 916 } 917 } 918 q->expire = time_second + dyn_ack_lifetime; 919 break; 920 921 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 922 if (dyn_fin_lifetime >= dyn_keepalive_period) 923 dyn_fin_lifetime = dyn_keepalive_period - 1; 924 q->expire = time_second + dyn_fin_lifetime; 925 break; 926 927 default: 928#if 0 929 /* 930 * reset or some invalid combination, but can also 931 * occur if we use keep-state the wrong way. 932 */ 933 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 934 printf("invalid state: 0x%x\n", q->state); 935#endif 936 if (dyn_rst_lifetime >= dyn_keepalive_period) 937 dyn_rst_lifetime = dyn_keepalive_period - 1; 938 q->expire = time_second + dyn_rst_lifetime; 939 break; 940 } 941 } else if (pkt->proto == IPPROTO_UDP) { 942 q->expire = time_second + dyn_udp_lifetime; 943 } else { 944 /* other protocols */ 945 q->expire = time_second + dyn_short_lifetime; 946 } 947done: 948 if (match_direction) 949 *match_direction = dir; 950 return q; 951} 952 953static ipfw_dyn_rule * 954lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 955 struct tcphdr *tcp) 956{ 957 ipfw_dyn_rule *q; 958 959 IPFW_DYN_LOCK(); 960 q = lookup_dyn_rule_locked(pkt, match_direction, tcp); 961 if (q == NULL) 962 IPFW_DYN_UNLOCK(); 963 /* NB: return table locked when q is not NULL */ 964 return q; 965} 966 967static void 968realloc_dynamic_table(void) 969{ 970 IPFW_DYN_LOCK_ASSERT(); 971 972 /* 973 * Try reallocation, make sure we have a power of 2 and do 974 * not allow more than 64k entries. In case of overflow, 975 * default to 1024. 976 */ 977 978 if (dyn_buckets > 65536) 979 dyn_buckets = 1024; 980 if ((dyn_buckets & (dyn_buckets-1)) != 0) { /* not a power of 2 */ 981 dyn_buckets = curr_dyn_buckets; /* reset */ 982 return; 983 } 984 curr_dyn_buckets = dyn_buckets; 985 if (ipfw_dyn_v != NULL) 986 free(ipfw_dyn_v, M_IPFW); 987 for (;;) { 988 ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof(ipfw_dyn_rule *), 989 M_IPFW, M_NOWAIT | M_ZERO); 990 if (ipfw_dyn_v != NULL || curr_dyn_buckets <= 2) 991 break; 992 curr_dyn_buckets /= 2; 993 } 994} 995 996/** 997 * Install state of type 'type' for a dynamic session. 998 * The hash table contains two type of rules: 999 * - regular rules (O_KEEP_STATE) 1000 * - rules for sessions with limited number of sess per user 1001 * (O_LIMIT). When they are created, the parent is 1002 * increased by 1, and decreased on delete. In this case, 1003 * the third parameter is the parent rule and not the chain. 1004 * - "parent" rules for the above (O_LIMIT_PARENT). 1005 */ 1006static ipfw_dyn_rule * 1007add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule) 1008{ 1009 ipfw_dyn_rule *r; 1010 int i; 1011 1012 IPFW_DYN_LOCK_ASSERT(); 1013 1014 if (ipfw_dyn_v == NULL || 1015 (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) { 1016 realloc_dynamic_table(); 1017 if (ipfw_dyn_v == NULL) 1018 return NULL; /* failed ! */ 1019 } 1020 i = hash_packet(id); 1021 1022 r = malloc(sizeof *r, M_IPFW, M_NOWAIT | M_ZERO); 1023 if (r == NULL) { 1024 printf ("ipfw: sorry cannot allocate state\n"); 1025 return NULL; 1026 } 1027 1028 /* increase refcount on parent, and set pointer */ 1029 if (dyn_type == O_LIMIT) { 1030 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 1031 if ( parent->dyn_type != O_LIMIT_PARENT) 1032 panic("invalid parent"); 1033 parent->count++; 1034 r->parent = parent; 1035 rule = parent->rule; 1036 } 1037 1038 r->id = *id; 1039 r->expire = time_second + dyn_syn_lifetime; 1040 r->rule = rule; 1041 r->dyn_type = dyn_type; 1042 r->pcnt = r->bcnt = 0; 1043 r->count = 0; 1044 1045 r->bucket = i; 1046 r->next = ipfw_dyn_v[i]; 1047 ipfw_dyn_v[i] = r; 1048 dyn_count++; 1049 DEB(printf("ipfw: add dyn entry ty %d 0x%08x %d -> 0x%08x %d, total %d\n", 1050 dyn_type, 1051 (r->id.src_ip), (r->id.src_port), 1052 (r->id.dst_ip), (r->id.dst_port), 1053 dyn_count ); ) 1054 return r; 1055} 1056 1057/** 1058 * lookup dynamic parent rule using pkt and rule as search keys. 1059 * If the lookup fails, then install one. 1060 */ 1061static ipfw_dyn_rule * 1062lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule) 1063{ 1064 ipfw_dyn_rule *q; 1065 int i; 1066 1067 IPFW_DYN_LOCK_ASSERT(); 1068 1069 if (ipfw_dyn_v) { 1070 i = hash_packet( pkt ); 1071 for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next) 1072 if (q->dyn_type == O_LIMIT_PARENT && 1073 rule== q->rule && 1074 pkt->proto == q->id.proto && 1075 pkt->src_ip == q->id.src_ip && 1076 pkt->dst_ip == q->id.dst_ip && 1077 pkt->src_port == q->id.src_port && 1078 pkt->dst_port == q->id.dst_port) { 1079 q->expire = time_second + dyn_short_lifetime; 1080 DEB(printf("ipfw: lookup_dyn_parent found 0x%p\n",q);) 1081 return q; 1082 } 1083 } 1084 return add_dyn_rule(pkt, O_LIMIT_PARENT, rule); 1085} 1086 1087/** 1088 * Install dynamic state for rule type cmd->o.opcode 1089 * 1090 * Returns 1 (failure) if state is not installed because of errors or because 1091 * session limitations are enforced. 1092 */ 1093static int 1094install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 1095 struct ip_fw_args *args) 1096{ 1097 static int last_log; 1098 1099 ipfw_dyn_rule *q; 1100 1101 DEB(printf("ipfw: install state type %d 0x%08x %u -> 0x%08x %u\n", 1102 cmd->o.opcode, 1103 (args->f_id.src_ip), (args->f_id.src_port), 1104 (args->f_id.dst_ip), (args->f_id.dst_port) );) 1105 1106 IPFW_DYN_LOCK(); 1107 1108 q = lookup_dyn_rule_locked(&args->f_id, NULL, NULL); 1109 1110 if (q != NULL) { /* should never occur */ 1111 if (last_log != time_second) { 1112 last_log = time_second; 1113 printf("ipfw: install_state: entry already present, done\n"); 1114 } 1115 IPFW_DYN_UNLOCK(); 1116 return 0; 1117 } 1118 1119 if (dyn_count >= dyn_max) 1120 /* 1121 * Run out of slots, try to remove any expired rule. 1122 */ 1123 remove_dyn_rule(NULL, (ipfw_dyn_rule *)1); 1124 1125 if (dyn_count >= dyn_max) { 1126 if (last_log != time_second) { 1127 last_log = time_second; 1128 printf("ipfw: install_state: Too many dynamic rules\n"); 1129 } 1130 IPFW_DYN_UNLOCK(); 1131 return 1; /* cannot install, notify caller */ 1132 } 1133 1134 switch (cmd->o.opcode) { 1135 case O_KEEP_STATE: /* bidir rule */ 1136 add_dyn_rule(&args->f_id, O_KEEP_STATE, rule); 1137 break; 1138 1139 case O_LIMIT: /* limit number of sessions */ 1140 { 1141 u_int16_t limit_mask = cmd->limit_mask; 1142 struct ipfw_flow_id id; 1143 ipfw_dyn_rule *parent; 1144 1145 DEB(printf("ipfw: installing dyn-limit rule %d\n", 1146 cmd->conn_limit);) 1147 1148 id.dst_ip = id.src_ip = 0; 1149 id.dst_port = id.src_port = 0; 1150 id.proto = args->f_id.proto; 1151 1152 if (limit_mask & DYN_SRC_ADDR) 1153 id.src_ip = args->f_id.src_ip; 1154 if (limit_mask & DYN_DST_ADDR) 1155 id.dst_ip = args->f_id.dst_ip; 1156 if (limit_mask & DYN_SRC_PORT) 1157 id.src_port = args->f_id.src_port; 1158 if (limit_mask & DYN_DST_PORT) 1159 id.dst_port = args->f_id.dst_port; 1160 parent = lookup_dyn_parent(&id, rule); 1161 if (parent == NULL) { 1162 printf("ipfw: add parent failed\n"); 1163 return 1; 1164 } 1165 if (parent->count >= cmd->conn_limit) { 1166 /* 1167 * See if we can remove some expired rule. 1168 */ 1169 remove_dyn_rule(rule, parent); 1170 if (parent->count >= cmd->conn_limit) { 1171 if (fw_verbose && last_log != time_second) { 1172 last_log = time_second; 1173 log(LOG_SECURITY | LOG_DEBUG, 1174 "drop session, too many entries\n"); 1175 } 1176 IPFW_DYN_UNLOCK(); 1177 return 1; 1178 } 1179 } 1180 add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent); 1181 } 1182 break; 1183 default: 1184 printf("ipfw: unknown dynamic rule type %u\n", cmd->o.opcode); 1185 IPFW_DYN_UNLOCK(); 1186 return 1; 1187 } 1188 lookup_dyn_rule_locked(&args->f_id, NULL, NULL); /* XXX just set lifetime */ 1189 IPFW_DYN_UNLOCK(); 1190 return 0; 1191} 1192 1193/* 1194 * Transmit a TCP packet, containing either a RST or a keepalive. 1195 * When flags & TH_RST, we are sending a RST packet, because of a 1196 * "reset" action matched the packet. 1197 * Otherwise we are sending a keepalive, and flags & TH_ 1198 */ 1199static void 1200send_pkt(struct ipfw_flow_id *id, u_int32_t seq, u_int32_t ack, int flags) 1201{ 1202 struct mbuf *m; 1203 struct ip *ip; 1204 struct tcphdr *tcp; 1205 1206 MGETHDR(m, M_DONTWAIT, MT_HEADER); 1207 if (m == 0) 1208 return; 1209 m->m_pkthdr.rcvif = (struct ifnet *)0; 1210 m->m_pkthdr.len = m->m_len = sizeof(struct ip) + sizeof(struct tcphdr); 1211 m->m_data += max_linkhdr; 1212 1213 ip = mtod(m, struct ip *); 1214 bzero(ip, m->m_len); 1215 tcp = (struct tcphdr *)(ip + 1); /* no IP options */ 1216 ip->ip_p = IPPROTO_TCP; 1217 tcp->th_off = 5; 1218 /* 1219 * Assume we are sending a RST (or a keepalive in the reverse 1220 * direction), swap src and destination addresses and ports. 1221 */ 1222 ip->ip_src.s_addr = htonl(id->dst_ip); 1223 ip->ip_dst.s_addr = htonl(id->src_ip); 1224 tcp->th_sport = htons(id->dst_port); 1225 tcp->th_dport = htons(id->src_port); 1226 if (flags & TH_RST) { /* we are sending a RST */ 1227 if (flags & TH_ACK) { 1228 tcp->th_seq = htonl(ack); 1229 tcp->th_ack = htonl(0); 1230 tcp->th_flags = TH_RST; 1231 } else { 1232 if (flags & TH_SYN) 1233 seq++; 1234 tcp->th_seq = htonl(0); 1235 tcp->th_ack = htonl(seq); 1236 tcp->th_flags = TH_RST | TH_ACK; 1237 } 1238 } else { 1239 /* 1240 * We are sending a keepalive. flags & TH_SYN determines 1241 * the direction, forward if set, reverse if clear. 1242 * NOTE: seq and ack are always assumed to be correct 1243 * as set by the caller. This may be confusing... 1244 */ 1245 if (flags & TH_SYN) { 1246 /* 1247 * we have to rewrite the correct addresses! 1248 */ 1249 ip->ip_dst.s_addr = htonl(id->dst_ip); 1250 ip->ip_src.s_addr = htonl(id->src_ip); 1251 tcp->th_dport = htons(id->dst_port); 1252 tcp->th_sport = htons(id->src_port); 1253 } 1254 tcp->th_seq = htonl(seq); 1255 tcp->th_ack = htonl(ack); 1256 tcp->th_flags = TH_ACK; 1257 } 1258 /* 1259 * set ip_len to the payload size so we can compute 1260 * the tcp checksum on the pseudoheader 1261 * XXX check this, could save a couple of words ? 1262 */ 1263 ip->ip_len = htons(sizeof(struct tcphdr)); 1264 tcp->th_sum = in_cksum(m, m->m_pkthdr.len); 1265 /* 1266 * now fill fields left out earlier 1267 */ 1268 ip->ip_ttl = ip_defttl; 1269 ip->ip_len = m->m_pkthdr.len; 1270 m->m_flags |= M_SKIP_FIREWALL; 1271 ip_output(m, NULL, NULL, 0, NULL, NULL); 1272} 1273 1274/* 1275 * sends a reject message, consuming the mbuf passed as an argument. 1276 */ 1277static void 1278send_reject(struct ip_fw_args *args, int code, int offset, int ip_len) 1279{ 1280 1281 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */ 1282 /* We need the IP header in host order for icmp_error(). */ 1283 if (args->eh != NULL) { 1284 struct ip *ip = mtod(args->m, struct ip *); 1285 ip->ip_len = ntohs(ip->ip_len); 1286 ip->ip_off = ntohs(ip->ip_off); 1287 } 1288 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 1289 } else if (offset == 0 && args->f_id.proto == IPPROTO_TCP) { 1290 struct tcphdr *const tcp = 1291 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 1292 if ( (tcp->th_flags & TH_RST) == 0) 1293 send_pkt(&(args->f_id), ntohl(tcp->th_seq), 1294 ntohl(tcp->th_ack), 1295 tcp->th_flags | TH_RST); 1296 m_freem(args->m); 1297 } else 1298 m_freem(args->m); 1299 args->m = NULL; 1300} 1301 1302/** 1303 * 1304 * Given an ip_fw *, lookup_next_rule will return a pointer 1305 * to the next rule, which can be either the jump 1306 * target (for skipto instructions) or the next one in the list (in 1307 * all other cases including a missing jump target). 1308 * The result is also written in the "next_rule" field of the rule. 1309 * Backward jumps are not allowed, so start looking from the next 1310 * rule... 1311 * 1312 * This never returns NULL -- in case we do not have an exact match, 1313 * the next rule is returned. When the ruleset is changed, 1314 * pointers are flushed so we are always correct. 1315 */ 1316 1317static struct ip_fw * 1318lookup_next_rule(struct ip_fw *me) 1319{ 1320 struct ip_fw *rule = NULL; 1321 ipfw_insn *cmd; 1322 1323 /* look for action, in case it is a skipto */ 1324 cmd = ACTION_PTR(me); 1325 if (cmd->opcode == O_LOG) 1326 cmd += F_LEN(cmd); 1327 if ( cmd->opcode == O_SKIPTO ) 1328 for (rule = me->next; rule ; rule = rule->next) 1329 if (rule->rulenum >= cmd->arg1) 1330 break; 1331 if (rule == NULL) /* failure or not a skipto */ 1332 rule = me->next; 1333 me->next_rule = rule; 1334 return rule; 1335} 1336 1337static void 1338init_tables(void) 1339{ 1340 int i; 1341 1342 for (i = 0; i < IPFW_TABLES_MAX; i++) { 1343 rn_inithead((void **)&ipfw_tables[i].rnh, 32); 1344 ipfw_tables[i].modified = 1; 1345 } 1346} 1347 1348static int 1349add_table_entry(u_int16_t tbl, in_addr_t addr, u_int8_t mlen, u_int32_t value) 1350{ 1351 struct radix_node_head *rnh; 1352 struct table_entry *ent; 1353 1354 if (tbl >= IPFW_TABLES_MAX) 1355 return (EINVAL); 1356 rnh = ipfw_tables[tbl].rnh; 1357 ent = malloc(sizeof(*ent), M_IPFW_TBL, M_NOWAIT | M_ZERO); 1358 if (ent == NULL) 1359 return (ENOMEM); 1360 ent->value = value; 1361 ent->addr.sin_len = ent->mask.sin_len = 8; 1362 ent->mask.sin_addr.s_addr = htonl(mlen ? ~((1 << (32 - mlen)) - 1) : 0); 1363 ent->addr.sin_addr.s_addr = addr & ent->mask.sin_addr.s_addr; 1364 RADIX_NODE_HEAD_LOCK(rnh); 1365 if (rnh->rnh_addaddr(&ent->addr, &ent->mask, rnh, (void *)ent) == 1366 NULL) { 1367 RADIX_NODE_HEAD_UNLOCK(rnh); 1368 free(ent, M_IPFW_TBL); 1369 return (EEXIST); 1370 } 1371 ipfw_tables[tbl].modified = 1; 1372 RADIX_NODE_HEAD_UNLOCK(rnh); 1373 return (0); 1374} 1375 1376static int 1377del_table_entry(u_int16_t tbl, in_addr_t addr, u_int8_t mlen) 1378{ 1379 struct radix_node_head *rnh; 1380 struct table_entry *ent; 1381 struct sockaddr_in sa, mask; 1382 1383 if (tbl >= IPFW_TABLES_MAX) 1384 return (EINVAL); 1385 rnh = ipfw_tables[tbl].rnh; 1386 sa.sin_len = mask.sin_len = 8; 1387 mask.sin_addr.s_addr = htonl(mlen ? ~((1 << (32 - mlen)) - 1) : 0); 1388 sa.sin_addr.s_addr = addr & mask.sin_addr.s_addr; 1389 RADIX_NODE_HEAD_LOCK(rnh); 1390 ent = (struct table_entry *)rnh->rnh_deladdr(&sa, &mask, rnh); 1391 if (ent == NULL) { 1392 RADIX_NODE_HEAD_UNLOCK(rnh); 1393 return (ESRCH); 1394 } 1395 ipfw_tables[tbl].modified = 1; 1396 RADIX_NODE_HEAD_UNLOCK(rnh); 1397 free(ent, M_IPFW_TBL); 1398 return (0); 1399} 1400 1401static int 1402flush_table_entry(struct radix_node *rn, void *arg) 1403{ 1404 struct radix_node_head * const rnh = arg; 1405 struct table_entry *ent; 1406 1407 ent = (struct table_entry *) 1408 rnh->rnh_deladdr(rn->rn_key, rn->rn_mask, rnh); 1409 if (ent != NULL) 1410 free(ent, M_IPFW_TBL); 1411 return (0); 1412} 1413 1414static int 1415flush_table(u_int16_t tbl) 1416{ 1417 struct radix_node_head *rnh; 1418 1419 if (tbl >= IPFW_TABLES_MAX) 1420 return (EINVAL); 1421 rnh = ipfw_tables[tbl].rnh; 1422 RADIX_NODE_HEAD_LOCK(rnh); 1423 rnh->rnh_walktree(rnh, flush_table_entry, rnh); 1424 ipfw_tables[tbl].modified = 1; 1425 RADIX_NODE_HEAD_UNLOCK(rnh); 1426 return (0); 1427} 1428 1429static void 1430flush_tables(void) 1431{ 1432 u_int16_t tbl; 1433 1434 for (tbl = 0; tbl < IPFW_TABLES_MAX; tbl++) 1435 flush_table(tbl); 1436} 1437 1438static int 1439lookup_table(u_int16_t tbl, in_addr_t addr, u_int32_t *val) 1440{ 1441 struct radix_node_head *rnh; 1442 struct table_entry *ent; 1443 struct sockaddr_in sa; 1444 static in_addr_t last_addr; 1445 static int last_tbl; 1446 static int last_match; 1447 static u_int32_t last_value; 1448 1449 if (tbl >= IPFW_TABLES_MAX) 1450 return (0); 1451 if (tbl == last_tbl && addr == last_addr && 1452 !ipfw_tables[tbl].modified) { 1453 if (last_match) 1454 *val = last_value; 1455 return (last_match); 1456 } 1457 rnh = ipfw_tables[tbl].rnh; 1458 sa.sin_len = 8; 1459 sa.sin_addr.s_addr = addr; 1460 RADIX_NODE_HEAD_LOCK(rnh); 1461 ipfw_tables[tbl].modified = 0; 1462 ent = (struct table_entry *)(rnh->rnh_lookup(&sa, NULL, rnh)); 1463 RADIX_NODE_HEAD_UNLOCK(rnh); 1464 last_addr = addr; 1465 last_tbl = tbl; 1466 if (ent != NULL) { 1467 last_value = *val = ent->value; 1468 last_match = 1; 1469 return (1); 1470 } 1471 last_match = 0; 1472 return (0); 1473} 1474 1475static int 1476count_table_entry(struct radix_node *rn, void *arg) 1477{ 1478 u_int32_t * const cnt = arg; 1479 1480 (*cnt)++; 1481 return (0); 1482} 1483 1484static int 1485count_table(u_int32_t tbl, u_int32_t *cnt) 1486{ 1487 struct radix_node_head *rnh; 1488 1489 if (tbl >= IPFW_TABLES_MAX) 1490 return (EINVAL); 1491 rnh = ipfw_tables[tbl].rnh; 1492 *cnt = 0; 1493 RADIX_NODE_HEAD_LOCK(rnh); 1494 rnh->rnh_walktree(rnh, count_table_entry, cnt); 1495 RADIX_NODE_HEAD_UNLOCK(rnh); 1496 return (0); 1497} 1498 1499static int 1500dump_table_entry(struct radix_node *rn, void *arg) 1501{ 1502 struct table_entry * const n = (struct table_entry *)rn; 1503 ipfw_table * const tbl = arg; 1504 ipfw_table_entry *ent; 1505 1506 if (tbl->cnt == tbl->size) 1507 return (1); 1508 ent = &tbl->ent[tbl->cnt]; 1509 ent->tbl = tbl->tbl; 1510 if (in_nullhost(n->mask.sin_addr)) 1511 ent->masklen = 0; 1512 else 1513 ent->masklen = 33 - ffs(ntohl(n->mask.sin_addr.s_addr)); 1514 ent->addr = n->addr.sin_addr.s_addr; 1515 ent->value = n->value; 1516 tbl->cnt++; 1517 return (0); 1518} 1519 1520static int 1521dump_table(ipfw_table *tbl) 1522{ 1523 struct radix_node_head *rnh; 1524 1525 if (tbl->tbl >= IPFW_TABLES_MAX) 1526 return (EINVAL); 1527 rnh = ipfw_tables[tbl->tbl].rnh; 1528 tbl->cnt = 0; 1529 RADIX_NODE_HEAD_LOCK(rnh); 1530 rnh->rnh_walktree(rnh, dump_table_entry, tbl); 1531 RADIX_NODE_HEAD_UNLOCK(rnh); 1532 return (0); 1533} 1534 1535static int 1536check_uidgid(ipfw_insn_u32 *insn, 1537 int proto, struct ifnet *oif, 1538 struct in_addr dst_ip, u_int16_t dst_port, 1539 struct in_addr src_ip, u_int16_t src_port, 1540 struct ip_fw_ugid *ugp, int *lookup) 1541{ 1542 struct inpcbinfo *pi; 1543 int wildcard; 1544 struct inpcb *pcb; 1545 int match; 1546 struct ucred *cr; 1547 gid_t *gp; 1548 1549 /* 1550 * If we have already been here and the packet has no 1551 * PCB entry associated with it, then we can safely 1552 * assume that this is a no match. 1553 */ 1554 if (*lookup == -1) 1555 return (0); 1556 if (proto == IPPROTO_TCP) { 1557 wildcard = 0; 1558 pi = &tcbinfo; 1559 } else if (proto == IPPROTO_UDP) { 1560 wildcard = 1; 1561 pi = &udbinfo; 1562 } else 1563 return 0; 1564 match = 0; 1565 if (*lookup == 0) { 1566 INP_INFO_RLOCK(pi); /* XXX LOR with IPFW */ 1567 pcb = (oif) ? 1568 in_pcblookup_hash(pi, 1569 dst_ip, htons(dst_port), 1570 src_ip, htons(src_port), 1571 wildcard, oif) : 1572 in_pcblookup_hash(pi, 1573 src_ip, htons(src_port), 1574 dst_ip, htons(dst_port), 1575 wildcard, NULL); 1576 if (pcb != NULL) { 1577 INP_LOCK(pcb); 1578 if (pcb->inp_socket != NULL) { 1579 cr = pcb->inp_socket->so_cred; 1580 ugp->fw_prid = jailed(cr) ? 1581 cr->cr_prison->pr_id : -1; 1582 ugp->fw_uid = cr->cr_uid; 1583 ugp->fw_ngroups = cr->cr_ngroups; 1584 bcopy(cr->cr_groups, ugp->fw_groups, 1585 sizeof(ugp->fw_groups)); 1586 *lookup = 1; 1587 } 1588 INP_UNLOCK(pcb); 1589 } 1590 INP_INFO_RUNLOCK(pi); 1591 if (*lookup == 0) { 1592 /* 1593 * If the lookup did not yield any results, there 1594 * is no sense in coming back and trying again. So 1595 * we can set lookup to -1 and ensure that we wont 1596 * bother the pcb system again. 1597 */ 1598 *lookup = -1; 1599 return (0); 1600 } 1601 } 1602 if (insn->o.opcode == O_UID) 1603 match = (ugp->fw_uid == (uid_t)insn->d[0]); 1604 else if (insn->o.opcode == O_GID) { 1605 for (gp = ugp->fw_groups; 1606 gp < &ugp->fw_groups[ugp->fw_ngroups]; gp++) 1607 if (*gp == (gid_t)insn->d[0]) { 1608 match = 1; 1609 break; 1610 } 1611 } else if (insn->o.opcode == O_JAIL) 1612 match = (ugp->fw_prid == (int)insn->d[0]); 1613 return match; 1614} 1615 1616/* 1617 * The main check routine for the firewall. 1618 * 1619 * All arguments are in args so we can modify them and return them 1620 * back to the caller. 1621 * 1622 * Parameters: 1623 * 1624 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 1625 * Starts with the IP header. 1626 * args->eh (in) Mac header if present, or NULL for layer3 packet. 1627 * args->oif Outgoing interface, or NULL if packet is incoming. 1628 * The incoming interface is in the mbuf. (in) 1629 * args->divert_rule (in/out) 1630 * Skip up to the first rule past this rule number; 1631 * upon return, non-zero port number for divert or tee. 1632 * 1633 * args->rule Pointer to the last matching rule (in/out) 1634 * args->next_hop Socket we are forwarding to (out). 1635 * args->f_id Addresses grabbed from the packet (out) 1636 * 1637 * Return value: 1638 * 1639 * IP_FW_PORT_DENY_FLAG the packet must be dropped. 1640 * 0 The packet is to be accepted and routed normally OR 1641 * the packet was denied/rejected and has been dropped; 1642 * in the latter case, *m is equal to NULL upon return. 1643 * port Divert the packet to port, with these caveats: 1644 * 1645 * - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead 1646 * of diverting it (ie, 'ipfw tee'). 1647 * 1648 * - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower 1649 * 16 bits as a dummynet pipe number instead of diverting 1650 */ 1651 1652int 1653ipfw_chk(struct ip_fw_args *args) 1654{ 1655 /* 1656 * Local variables hold state during the processing of a packet. 1657 * 1658 * IMPORTANT NOTE: to speed up the processing of rules, there 1659 * are some assumption on the values of the variables, which 1660 * are documented here. Should you change them, please check 1661 * the implementation of the various instructions to make sure 1662 * that they still work. 1663 * 1664 * args->eh The MAC header. It is non-null for a layer2 1665 * packet, it is NULL for a layer-3 packet. 1666 * 1667 * m | args->m Pointer to the mbuf, as received from the caller. 1668 * It may change if ipfw_chk() does an m_pullup, or if it 1669 * consumes the packet because it calls send_reject(). 1670 * XXX This has to change, so that ipfw_chk() never modifies 1671 * or consumes the buffer. 1672 * ip is simply an alias of the value of m, and it is kept 1673 * in sync with it (the packet is supposed to start with 1674 * the ip header). 1675 */ 1676 struct mbuf *m = args->m; 1677 struct ip *ip = mtod(m, struct ip *); 1678 1679 /* 1680 * For rules which contain uid/gid or jail constraints, cache 1681 * a copy of the users credentials after the pcb lookup has been 1682 * executed. This will speed up the processing of rules with 1683 * these types of constraints, as well as decrease contention 1684 * on pcb related locks. 1685 */ 1686 struct ip_fw_ugid fw_ugid_cache; 1687 int ugid_lookup = 0; 1688 1689 /* 1690 * oif | args->oif If NULL, ipfw_chk has been called on the 1691 * inbound path (ether_input, bdg_forward, ip_input). 1692 * If non-NULL, ipfw_chk has been called on the outbound path 1693 * (ether_output, ip_output). 1694 */ 1695 struct ifnet *oif = args->oif; 1696 1697 struct ip_fw *f = NULL; /* matching rule */ 1698 int retval = 0; 1699 1700 /* 1701 * hlen The length of the IPv4 header. 1702 * hlen >0 means we have an IPv4 packet. 1703 */ 1704 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 1705 1706 /* 1707 * offset The offset of a fragment. offset != 0 means that 1708 * we have a fragment at this offset of an IPv4 packet. 1709 * offset == 0 means that (if this is an IPv4 packet) 1710 * this is the first or only fragment. 1711 */ 1712 u_short offset = 0; 1713 1714 /* 1715 * Local copies of addresses. They are only valid if we have 1716 * an IP packet. 1717 * 1718 * proto The protocol. Set to 0 for non-ip packets, 1719 * or to the protocol read from the packet otherwise. 1720 * proto != 0 means that we have an IPv4 packet. 1721 * 1722 * src_port, dst_port port numbers, in HOST format. Only 1723 * valid for TCP and UDP packets. 1724 * 1725 * src_ip, dst_ip ip addresses, in NETWORK format. 1726 * Only valid for IPv4 packets. 1727 */ 1728 u_int8_t proto; 1729 u_int16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 1730 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 1731 u_int16_t ip_len=0; 1732 int pktlen; 1733 int dyn_dir = MATCH_UNKNOWN; 1734 ipfw_dyn_rule *q = NULL; 1735 struct ip_fw_chain *chain = &layer3_chain; 1736 struct m_tag *mtag; 1737 1738 if (m->m_flags & M_SKIP_FIREWALL) 1739 return 0; /* accept */ 1740 /* 1741 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 1742 * MATCH_NONE when checked and not matched (q = NULL), 1743 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 1744 */ 1745 1746 pktlen = m->m_pkthdr.len; 1747 if (args->eh == NULL || /* layer 3 packet */ 1748 ( m->m_pkthdr.len >= sizeof(struct ip) && 1749 ntohs(args->eh->ether_type) == ETHERTYPE_IP)) 1750 hlen = ip->ip_hl << 2; 1751 1752 /* 1753 * Collect parameters into local variables for faster matching. 1754 */ 1755 if (hlen == 0) { /* do not grab addresses for non-ip pkts */ 1756 proto = args->f_id.proto = 0; /* mark f_id invalid */ 1757 goto after_ip_checks; 1758 } 1759 1760 proto = args->f_id.proto = ip->ip_p; 1761 src_ip = ip->ip_src; 1762 dst_ip = ip->ip_dst; 1763 if (args->eh != NULL) { /* layer 2 packets are as on the wire */ 1764 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1765 ip_len = ntohs(ip->ip_len); 1766 } else { 1767 offset = ip->ip_off & IP_OFFMASK; 1768 ip_len = ip->ip_len; 1769 } 1770 pktlen = ip_len < pktlen ? ip_len : pktlen; 1771 1772#define PULLUP_TO(len) \ 1773 do { \ 1774 if ((m)->m_len < (len)) { \ 1775 args->m = m = m_pullup(m, (len)); \ 1776 if (m == 0) \ 1777 goto pullup_failed; \ 1778 ip = mtod(m, struct ip *); \ 1779 } \ 1780 } while (0) 1781 1782 if (offset == 0) { 1783 switch (proto) { 1784 case IPPROTO_TCP: 1785 { 1786 struct tcphdr *tcp; 1787 1788 PULLUP_TO(hlen + sizeof(struct tcphdr)); 1789 tcp = L3HDR(struct tcphdr, ip); 1790 dst_port = tcp->th_dport; 1791 src_port = tcp->th_sport; 1792 args->f_id.flags = tcp->th_flags; 1793 } 1794 break; 1795 1796 case IPPROTO_UDP: 1797 { 1798 struct udphdr *udp; 1799 1800 PULLUP_TO(hlen + sizeof(struct udphdr)); 1801 udp = L3HDR(struct udphdr, ip); 1802 dst_port = udp->uh_dport; 1803 src_port = udp->uh_sport; 1804 } 1805 break; 1806 1807 case IPPROTO_ICMP: 1808 PULLUP_TO(hlen + 4); /* type, code and checksum. */ 1809 args->f_id.flags = L3HDR(struct icmp, ip)->icmp_type; 1810 break; 1811 1812 default: 1813 break; 1814 } 1815#undef PULLUP_TO 1816 } 1817 1818 args->f_id.src_ip = ntohl(src_ip.s_addr); 1819 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1820 args->f_id.src_port = src_port = ntohs(src_port); 1821 args->f_id.dst_port = dst_port = ntohs(dst_port); 1822 1823after_ip_checks: 1824 IPFW_LOCK(chain); /* XXX expensive? can we run lock free? */ 1825 mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL); 1826 if (args->rule) { 1827 /* 1828 * Packet has already been tagged. Look for the next rule 1829 * to restart processing. 1830 * 1831 * If fw_one_pass != 0 then just accept it. 1832 * XXX should not happen here, but optimized out in 1833 * the caller. 1834 */ 1835 if (fw_one_pass) { 1836 IPFW_UNLOCK(chain); /* XXX optimize */ 1837 return 0; 1838 } 1839 1840 f = args->rule->next_rule; 1841 if (f == NULL) 1842 f = lookup_next_rule(args->rule); 1843 } else { 1844 /* 1845 * Find the starting rule. It can be either the first 1846 * one, or the one after divert_rule if asked so. 1847 */ 1848 int skipto = mtag ? divert_cookie(mtag) : 0; 1849 1850 f = chain->rules; 1851 if (args->eh == NULL && skipto != 0) { 1852 if (skipto >= IPFW_DEFAULT_RULE) { 1853 IPFW_UNLOCK(chain); 1854 return(IP_FW_PORT_DENY_FLAG); /* invalid */ 1855 } 1856 while (f && f->rulenum <= skipto) 1857 f = f->next; 1858 if (f == NULL) { /* drop packet */ 1859 IPFW_UNLOCK(chain); 1860 return(IP_FW_PORT_DENY_FLAG); 1861 } 1862 } 1863 } 1864 /* reset divert rule to avoid confusion later */ 1865 if (mtag) 1866 m_tag_delete(m, mtag); 1867 1868 /* 1869 * Now scan the rules, and parse microinstructions for each rule. 1870 */ 1871 for (; f; f = f->next) { 1872 int l, cmdlen; 1873 ipfw_insn *cmd; 1874 int skip_or; /* skip rest of OR block */ 1875 1876again: 1877 if (set_disable & (1 << f->set) ) 1878 continue; 1879 1880 skip_or = 0; 1881 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1882 l -= cmdlen, cmd += cmdlen) { 1883 int match; 1884 1885 /* 1886 * check_body is a jump target used when we find a 1887 * CHECK_STATE, and need to jump to the body of 1888 * the target rule. 1889 */ 1890 1891check_body: 1892 cmdlen = F_LEN(cmd); 1893 /* 1894 * An OR block (insn_1 || .. || insn_n) has the 1895 * F_OR bit set in all but the last instruction. 1896 * The first match will set "skip_or", and cause 1897 * the following instructions to be skipped until 1898 * past the one with the F_OR bit clear. 1899 */ 1900 if (skip_or) { /* skip this instruction */ 1901 if ((cmd->len & F_OR) == 0) 1902 skip_or = 0; /* next one is good */ 1903 continue; 1904 } 1905 match = 0; /* set to 1 if we succeed */ 1906 1907 switch (cmd->opcode) { 1908 /* 1909 * The first set of opcodes compares the packet's 1910 * fields with some pattern, setting 'match' if a 1911 * match is found. At the end of the loop there is 1912 * logic to deal with F_NOT and F_OR flags associated 1913 * with the opcode. 1914 */ 1915 case O_NOP: 1916 match = 1; 1917 break; 1918 1919 case O_FORWARD_MAC: 1920 printf("ipfw: opcode %d unimplemented\n", 1921 cmd->opcode); 1922 break; 1923 1924 case O_GID: 1925 case O_UID: 1926 case O_JAIL: 1927 /* 1928 * We only check offset == 0 && proto != 0, 1929 * as this ensures that we have an IPv4 1930 * packet with the ports info. 1931 */ 1932 if (offset!=0) 1933 break; 1934 if (proto == IPPROTO_TCP || 1935 proto == IPPROTO_UDP) 1936 match = check_uidgid( 1937 (ipfw_insn_u32 *)cmd, 1938 proto, oif, 1939 dst_ip, dst_port, 1940 src_ip, src_port, &fw_ugid_cache, 1941 &ugid_lookup); 1942 break; 1943 1944 case O_RECV: 1945 match = iface_match(m->m_pkthdr.rcvif, 1946 (ipfw_insn_if *)cmd); 1947 break; 1948 1949 case O_XMIT: 1950 match = iface_match(oif, (ipfw_insn_if *)cmd); 1951 break; 1952 1953 case O_VIA: 1954 match = iface_match(oif ? oif : 1955 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd); 1956 break; 1957 1958 case O_MACADDR2: 1959 if (args->eh != NULL) { /* have MAC header */ 1960 u_int32_t *want = (u_int32_t *) 1961 ((ipfw_insn_mac *)cmd)->addr; 1962 u_int32_t *mask = (u_int32_t *) 1963 ((ipfw_insn_mac *)cmd)->mask; 1964 u_int32_t *hdr = (u_int32_t *)args->eh; 1965 1966 match = 1967 ( want[0] == (hdr[0] & mask[0]) && 1968 want[1] == (hdr[1] & mask[1]) && 1969 want[2] == (hdr[2] & mask[2]) ); 1970 } 1971 break; 1972 1973 case O_MAC_TYPE: 1974 if (args->eh != NULL) { 1975 u_int16_t t = 1976 ntohs(args->eh->ether_type); 1977 u_int16_t *p = 1978 ((ipfw_insn_u16 *)cmd)->ports; 1979 int i; 1980 1981 for (i = cmdlen - 1; !match && i>0; 1982 i--, p += 2) 1983 match = (t>=p[0] && t<=p[1]); 1984 } 1985 break; 1986 1987 case O_FRAG: 1988 match = (hlen > 0 && offset != 0); 1989 break; 1990 1991 case O_IN: /* "out" is "not in" */ 1992 match = (oif == NULL); 1993 break; 1994 1995 case O_LAYER2: 1996 match = (args->eh != NULL); 1997 break; 1998 1999 case O_PROTO: 2000 /* 2001 * We do not allow an arg of 0 so the 2002 * check of "proto" only suffices. 2003 */ 2004 match = (proto == cmd->arg1); 2005 break; 2006 2007 case O_IP_SRC: 2008 match = (hlen > 0 && 2009 ((ipfw_insn_ip *)cmd)->addr.s_addr == 2010 src_ip.s_addr); 2011 break; 2012 2013 case O_IP_SRC_LOOKUP: 2014 case O_IP_DST_LOOKUP: 2015 if (hlen > 0) { 2016 uint32_t a = 2017 (cmd->opcode == O_IP_DST_LOOKUP) ? 2018 dst_ip.s_addr : src_ip.s_addr; 2019 uint32_t v; 2020 2021 match = lookup_table(cmd->arg1, a, &v); 2022 if (!match) 2023 break; 2024 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 2025 match = 2026 ((ipfw_insn_u32 *)cmd)->d[0] == v; 2027 } 2028 break; 2029 2030 case O_IP_SRC_MASK: 2031 case O_IP_DST_MASK: 2032 if (hlen > 0) { 2033 uint32_t a = 2034 (cmd->opcode == O_IP_DST_MASK) ? 2035 dst_ip.s_addr : src_ip.s_addr; 2036 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 2037 int i = cmdlen-1; 2038 2039 for (; !match && i>0; i-= 2, p+= 2) 2040 match = (p[0] == (a & p[1])); 2041 } 2042 break; 2043 2044 case O_IP_SRC_ME: 2045 if (hlen > 0) { 2046 struct ifnet *tif; 2047 2048 INADDR_TO_IFP(src_ip, tif); 2049 match = (tif != NULL); 2050 } 2051 break; 2052 2053 case O_IP_DST_SET: 2054 case O_IP_SRC_SET: 2055 if (hlen > 0) { 2056 u_int32_t *d = (u_int32_t *)(cmd+1); 2057 u_int32_t addr = 2058 cmd->opcode == O_IP_DST_SET ? 2059 args->f_id.dst_ip : 2060 args->f_id.src_ip; 2061 2062 if (addr < d[0]) 2063 break; 2064 addr -= d[0]; /* subtract base */ 2065 match = (addr < cmd->arg1) && 2066 ( d[ 1 + (addr>>5)] & 2067 (1<<(addr & 0x1f)) ); 2068 } 2069 break; 2070 2071 case O_IP_DST: 2072 match = (hlen > 0 && 2073 ((ipfw_insn_ip *)cmd)->addr.s_addr == 2074 dst_ip.s_addr); 2075 break; 2076 2077 case O_IP_DST_ME: 2078 if (hlen > 0) { 2079 struct ifnet *tif; 2080 2081 INADDR_TO_IFP(dst_ip, tif); 2082 match = (tif != NULL); 2083 } 2084 break; 2085 2086 case O_IP_SRCPORT: 2087 case O_IP_DSTPORT: 2088 /* 2089 * offset == 0 && proto != 0 is enough 2090 * to guarantee that we have an IPv4 2091 * packet with port info. 2092 */ 2093 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP) 2094 && offset == 0) { 2095 u_int16_t x = 2096 (cmd->opcode == O_IP_SRCPORT) ? 2097 src_port : dst_port ; 2098 u_int16_t *p = 2099 ((ipfw_insn_u16 *)cmd)->ports; 2100 int i; 2101 2102 for (i = cmdlen - 1; !match && i>0; 2103 i--, p += 2) 2104 match = (x>=p[0] && x<=p[1]); 2105 } 2106 break; 2107 2108 case O_ICMPTYPE: 2109 match = (offset == 0 && proto==IPPROTO_ICMP && 2110 icmptype_match(ip, (ipfw_insn_u32 *)cmd) ); 2111 break; 2112 2113 case O_IPOPT: 2114 match = (hlen > 0 && ipopts_match(ip, cmd) ); 2115 break; 2116 2117 case O_IPVER: 2118 match = (hlen > 0 && cmd->arg1 == ip->ip_v); 2119 break; 2120 2121 case O_IPID: 2122 case O_IPLEN: 2123 case O_IPTTL: 2124 if (hlen > 0) { /* only for IP packets */ 2125 uint16_t x; 2126 uint16_t *p; 2127 int i; 2128 2129 if (cmd->opcode == O_IPLEN) 2130 x = ip_len; 2131 else if (cmd->opcode == O_IPTTL) 2132 x = ip->ip_ttl; 2133 else /* must be IPID */ 2134 x = ntohs(ip->ip_id); 2135 if (cmdlen == 1) { 2136 match = (cmd->arg1 == x); 2137 break; 2138 } 2139 /* otherwise we have ranges */ 2140 p = ((ipfw_insn_u16 *)cmd)->ports; 2141 i = cmdlen - 1; 2142 for (; !match && i>0; i--, p += 2) 2143 match = (x >= p[0] && x <= p[1]); 2144 } 2145 break; 2146 2147 case O_IPPRECEDENCE: 2148 match = (hlen > 0 && 2149 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 2150 break; 2151 2152 case O_IPTOS: 2153 match = (hlen > 0 && 2154 flags_match(cmd, ip->ip_tos)); 2155 break; 2156 2157 case O_TCPFLAGS: 2158 match = (proto == IPPROTO_TCP && offset == 0 && 2159 flags_match(cmd, 2160 L3HDR(struct tcphdr,ip)->th_flags)); 2161 break; 2162 2163 case O_TCPOPTS: 2164 match = (proto == IPPROTO_TCP && offset == 0 && 2165 tcpopts_match(ip, cmd)); 2166 break; 2167 2168 case O_TCPSEQ: 2169 match = (proto == IPPROTO_TCP && offset == 0 && 2170 ((ipfw_insn_u32 *)cmd)->d[0] == 2171 L3HDR(struct tcphdr,ip)->th_seq); 2172 break; 2173 2174 case O_TCPACK: 2175 match = (proto == IPPROTO_TCP && offset == 0 && 2176 ((ipfw_insn_u32 *)cmd)->d[0] == 2177 L3HDR(struct tcphdr,ip)->th_ack); 2178 break; 2179 2180 case O_TCPWIN: 2181 match = (proto == IPPROTO_TCP && offset == 0 && 2182 cmd->arg1 == 2183 L3HDR(struct tcphdr,ip)->th_win); 2184 break; 2185 2186 case O_ESTAB: 2187 /* reject packets which have SYN only */ 2188 /* XXX should i also check for TH_ACK ? */ 2189 match = (proto == IPPROTO_TCP && offset == 0 && 2190 (L3HDR(struct tcphdr,ip)->th_flags & 2191 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 2192 break; 2193 2194 case O_LOG: 2195 if (fw_verbose) 2196 ipfw_log(f, hlen, args->eh, m, oif); 2197 match = 1; 2198 break; 2199 2200 case O_PROB: 2201 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 2202 break; 2203 2204 case O_VERREVPATH: 2205 /* Outgoing packets automatically pass/match */ 2206 match = (hlen > 0 && ((oif != NULL) || 2207 (m->m_pkthdr.rcvif == NULL) || 2208 verify_path(src_ip, m->m_pkthdr.rcvif))); 2209 break; 2210 2211 case O_VERSRCREACH: 2212 /* Outgoing packets automatically pass/match */ 2213 match = (hlen > 0 && ((oif != NULL) || 2214 verify_path(src_ip, NULL))); 2215 break; 2216 2217 case O_ANTISPOOF: 2218 /* Outgoing packets automatically pass/match */ 2219 if (oif == NULL && hlen > 0 && 2220 in_localaddr(src_ip)) 2221 match = verify_path(src_ip, 2222 m->m_pkthdr.rcvif); 2223 else 2224 match = 1; 2225 break; 2226 2227 case O_IPSEC: 2228#ifdef FAST_IPSEC 2229 match = (m_tag_find(m, 2230 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 2231#endif 2232#ifdef IPSEC 2233 match = (ipsec_getnhist(m) != 0); 2234#endif 2235 /* otherwise no match */ 2236 break; 2237 2238 /* 2239 * The second set of opcodes represents 'actions', 2240 * i.e. the terminal part of a rule once the packet 2241 * matches all previous patterns. 2242 * Typically there is only one action for each rule, 2243 * and the opcode is stored at the end of the rule 2244 * (but there are exceptions -- see below). 2245 * 2246 * In general, here we set retval and terminate the 2247 * outer loop (would be a 'break 3' in some language, 2248 * but we need to do a 'goto done'). 2249 * 2250 * Exceptions: 2251 * O_COUNT and O_SKIPTO actions: 2252 * instead of terminating, we jump to the next rule 2253 * ('goto next_rule', equivalent to a 'break 2'), 2254 * or to the SKIPTO target ('goto again' after 2255 * having set f, cmd and l), respectively. 2256 * 2257 * O_LIMIT and O_KEEP_STATE: these opcodes are 2258 * not real 'actions', and are stored right 2259 * before the 'action' part of the rule. 2260 * These opcodes try to install an entry in the 2261 * state tables; if successful, we continue with 2262 * the next opcode (match=1; break;), otherwise 2263 * the packet * must be dropped 2264 * ('goto done' after setting retval); 2265 * 2266 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 2267 * cause a lookup of the state table, and a jump 2268 * to the 'action' part of the parent rule 2269 * ('goto check_body') if an entry is found, or 2270 * (CHECK_STATE only) a jump to the next rule if 2271 * the entry is not found ('goto next_rule'). 2272 * The result of the lookup is cached to make 2273 * further instances of these opcodes are 2274 * effectively NOPs. 2275 */ 2276 case O_LIMIT: 2277 case O_KEEP_STATE: 2278 if (install_state(f, 2279 (ipfw_insn_limit *)cmd, args)) { 2280 retval = IP_FW_PORT_DENY_FLAG; 2281 goto done; /* error/limit violation */ 2282 } 2283 match = 1; 2284 break; 2285 2286 case O_PROBE_STATE: 2287 case O_CHECK_STATE: 2288 /* 2289 * dynamic rules are checked at the first 2290 * keep-state or check-state occurrence, 2291 * with the result being stored in dyn_dir. 2292 * The compiler introduces a PROBE_STATE 2293 * instruction for us when we have a 2294 * KEEP_STATE (because PROBE_STATE needs 2295 * to be run first). 2296 */ 2297 if (dyn_dir == MATCH_UNKNOWN && 2298 (q = lookup_dyn_rule(&args->f_id, 2299 &dyn_dir, proto == IPPROTO_TCP ? 2300 L3HDR(struct tcphdr, ip) : NULL)) 2301 != NULL) { 2302 /* 2303 * Found dynamic entry, update stats 2304 * and jump to the 'action' part of 2305 * the parent rule. 2306 */ 2307 q->pcnt++; 2308 q->bcnt += pktlen; 2309 f = q->rule; 2310 cmd = ACTION_PTR(f); 2311 l = f->cmd_len - f->act_ofs; 2312 IPFW_DYN_UNLOCK(); 2313 goto check_body; 2314 } 2315 /* 2316 * Dynamic entry not found. If CHECK_STATE, 2317 * skip to next rule, if PROBE_STATE just 2318 * ignore and continue with next opcode. 2319 */ 2320 if (cmd->opcode == O_CHECK_STATE) 2321 goto next_rule; 2322 match = 1; 2323 break; 2324 2325 case O_ACCEPT: 2326 retval = 0; /* accept */ 2327 goto done; 2328 2329 case O_PIPE: 2330 case O_QUEUE: 2331 args->rule = f; /* report matching rule */ 2332 retval = cmd->arg1 | IP_FW_PORT_DYNT_FLAG; 2333 goto done; 2334 2335 case O_DIVERT: 2336 case O_TEE: { 2337 struct divert_tag *dt; 2338 2339 if (args->eh) /* not on layer 2 */ 2340 break; 2341 mtag = m_tag_get(PACKET_TAG_DIVERT, 2342 sizeof(struct divert_tag), 2343 M_NOWAIT); 2344 if (mtag == NULL) { 2345 /* XXX statistic */ 2346 /* drop packet */ 2347 IPFW_UNLOCK(chain); 2348 return IP_FW_PORT_DENY_FLAG; 2349 } 2350 dt = (struct divert_tag *)(mtag+1); 2351 dt->cookie = f->rulenum; 2352 dt->info = (cmd->opcode == O_DIVERT) ? 2353 cmd->arg1 : 2354 cmd->arg1 | IP_FW_PORT_TEE_FLAG; 2355 m_tag_prepend(m, mtag); 2356 retval = dt->info; 2357 goto done; 2358 } 2359 2360 case O_COUNT: 2361 case O_SKIPTO: 2362 f->pcnt++; /* update stats */ 2363 f->bcnt += pktlen; 2364 f->timestamp = time_second; 2365 if (cmd->opcode == O_COUNT) 2366 goto next_rule; 2367 /* handle skipto */ 2368 if (f->next_rule == NULL) 2369 lookup_next_rule(f); 2370 f = f->next_rule; 2371 goto again; 2372 2373 case O_REJECT: 2374 /* 2375 * Drop the packet and send a reject notice 2376 * if the packet is not ICMP (or is an ICMP 2377 * query), and it is not multicast/broadcast. 2378 */ 2379 if (hlen > 0 && 2380 (proto != IPPROTO_ICMP || 2381 is_icmp_query(ip)) && 2382 !(m->m_flags & (M_BCAST|M_MCAST)) && 2383 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2384 send_reject(args, cmd->arg1, 2385 offset,ip_len); 2386 m = args->m; 2387 } 2388 /* FALLTHROUGH */ 2389 case O_DENY: 2390 retval = IP_FW_PORT_DENY_FLAG; 2391 goto done; 2392 2393 case O_FORWARD_IP: 2394 if (args->eh) /* not valid on layer2 pkts */ 2395 break; 2396 if (!q || dyn_dir == MATCH_FORWARD) 2397 args->next_hop = 2398 &((ipfw_insn_sa *)cmd)->sa; 2399 retval = 0; 2400 goto done; 2401 2402 default: 2403 panic("-- unknown opcode %d\n", cmd->opcode); 2404 } /* end of switch() on opcodes */ 2405 2406 if (cmd->len & F_NOT) 2407 match = !match; 2408 2409 if (match) { 2410 if (cmd->len & F_OR) 2411 skip_or = 1; 2412 } else { 2413 if (!(cmd->len & F_OR)) /* not an OR block, */ 2414 break; /* try next rule */ 2415 } 2416 2417 } /* end of inner for, scan opcodes */ 2418 2419next_rule:; /* try next rule */ 2420 2421 } /* end of outer for, scan rules */ 2422 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 2423 IPFW_UNLOCK(chain); 2424 return(IP_FW_PORT_DENY_FLAG); 2425 2426done: 2427 /* Update statistics */ 2428 f->pcnt++; 2429 f->bcnt += pktlen; 2430 f->timestamp = time_second; 2431 IPFW_UNLOCK(chain); 2432 return retval; 2433 2434pullup_failed: 2435 if (fw_verbose) 2436 printf("ipfw: pullup failed\n"); 2437 return(IP_FW_PORT_DENY_FLAG); 2438} 2439 2440/* 2441 * When a rule is added/deleted, clear the next_rule pointers in all rules. 2442 * These will be reconstructed on the fly as packets are matched. 2443 */ 2444static void 2445flush_rule_ptrs(struct ip_fw_chain *chain) 2446{ 2447 struct ip_fw *rule; 2448 2449 IPFW_LOCK_ASSERT(chain); 2450 2451 for (rule = chain->rules; rule; rule = rule->next) 2452 rule->next_rule = NULL; 2453} 2454 2455/* 2456 * When pipes/queues are deleted, clear the "pipe_ptr" pointer to a given 2457 * pipe/queue, or to all of them (match == NULL). 2458 */ 2459void 2460flush_pipe_ptrs(struct dn_flow_set *match) 2461{ 2462 struct ip_fw *rule; 2463 2464 IPFW_LOCK(&layer3_chain); 2465 for (rule = layer3_chain.rules; rule; rule = rule->next) { 2466 ipfw_insn_pipe *cmd = (ipfw_insn_pipe *)ACTION_PTR(rule); 2467 2468 if (cmd->o.opcode != O_PIPE && cmd->o.opcode != O_QUEUE) 2469 continue; 2470 /* 2471 * XXX Use bcmp/bzero to handle pipe_ptr to overcome 2472 * possible alignment problems on 64-bit architectures. 2473 * This code is seldom used so we do not worry too 2474 * much about efficiency. 2475 */ 2476 if (match == NULL || 2477 !bcmp(&cmd->pipe_ptr, &match, sizeof(match)) ) 2478 bzero(&cmd->pipe_ptr, sizeof(cmd->pipe_ptr)); 2479 } 2480 IPFW_UNLOCK(&layer3_chain); 2481} 2482 2483/* 2484 * Add a new rule to the list. Copy the rule into a malloc'ed area, then 2485 * possibly create a rule number and add the rule to the list. 2486 * Update the rule_number in the input struct so the caller knows it as well. 2487 */ 2488static int 2489add_rule(struct ip_fw_chain *chain, struct ip_fw *input_rule) 2490{ 2491 struct ip_fw *rule, *f, *prev; 2492 int l = RULESIZE(input_rule); 2493 2494 if (chain->rules == NULL && input_rule->rulenum != IPFW_DEFAULT_RULE) 2495 return (EINVAL); 2496 2497 rule = malloc(l, M_IPFW, M_NOWAIT | M_ZERO); 2498 if (rule == NULL) 2499 return (ENOSPC); 2500 2501 bcopy(input_rule, rule, l); 2502 2503 rule->next = NULL; 2504 rule->next_rule = NULL; 2505 2506 rule->pcnt = 0; 2507 rule->bcnt = 0; 2508 rule->timestamp = 0; 2509 2510 IPFW_LOCK(chain); 2511 2512 if (chain->rules == NULL) { /* default rule */ 2513 chain->rules = rule; 2514 goto done; 2515 } 2516 2517 /* 2518 * If rulenum is 0, find highest numbered rule before the 2519 * default rule, and add autoinc_step 2520 */ 2521 if (autoinc_step < 1) 2522 autoinc_step = 1; 2523 else if (autoinc_step > 1000) 2524 autoinc_step = 1000; 2525 if (rule->rulenum == 0) { 2526 /* 2527 * locate the highest numbered rule before default 2528 */ 2529 for (f = chain->rules; f; f = f->next) { 2530 if (f->rulenum == IPFW_DEFAULT_RULE) 2531 break; 2532 rule->rulenum = f->rulenum; 2533 } 2534 if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step) 2535 rule->rulenum += autoinc_step; 2536 input_rule->rulenum = rule->rulenum; 2537 } 2538 2539 /* 2540 * Now insert the new rule in the right place in the sorted list. 2541 */ 2542 for (prev = NULL, f = chain->rules; f; prev = f, f = f->next) { 2543 if (f->rulenum > rule->rulenum) { /* found the location */ 2544 if (prev) { 2545 rule->next = f; 2546 prev->next = rule; 2547 } else { /* head insert */ 2548 rule->next = chain->rules; 2549 chain->rules = rule; 2550 } 2551 break; 2552 } 2553 } 2554 flush_rule_ptrs(chain); 2555done: 2556 static_count++; 2557 static_len += l; 2558 IPFW_UNLOCK(chain); 2559 DEB(printf("ipfw: installed rule %d, static count now %d\n", 2560 rule->rulenum, static_count);) 2561 return (0); 2562} 2563 2564/** 2565 * Remove a static rule (including derived * dynamic rules) 2566 * and place it on the ``reap list'' for later reclamation. 2567 * The caller is in charge of clearing rule pointers to avoid 2568 * dangling pointers. 2569 * @return a pointer to the next entry. 2570 * Arguments are not checked, so they better be correct. 2571 */ 2572static struct ip_fw * 2573remove_rule(struct ip_fw_chain *chain, struct ip_fw *rule, struct ip_fw *prev) 2574{ 2575 struct ip_fw *n; 2576 int l = RULESIZE(rule); 2577 2578 IPFW_LOCK_ASSERT(chain); 2579 2580 n = rule->next; 2581 IPFW_DYN_LOCK(); 2582 remove_dyn_rule(rule, NULL /* force removal */); 2583 IPFW_DYN_UNLOCK(); 2584 if (prev == NULL) 2585 chain->rules = n; 2586 else 2587 prev->next = n; 2588 static_count--; 2589 static_len -= l; 2590 2591 rule->next = chain->reap; 2592 chain->reap = rule; 2593 2594 return n; 2595} 2596 2597/** 2598 * Reclaim storage associated with a list of rules. This is 2599 * typically the list created using remove_rule. 2600 */ 2601static void 2602reap_rules(struct ip_fw *head) 2603{ 2604 struct ip_fw *rule; 2605 2606 while ((rule = head) != NULL) { 2607 head = head->next; 2608 if (DUMMYNET_LOADED) 2609 ip_dn_ruledel_ptr(rule); 2610 free(rule, M_IPFW); 2611 } 2612} 2613 2614/* 2615 * Remove all rules from a chain (except rules in set RESVD_SET 2616 * unless kill_default = 1). The caller is responsible for 2617 * reclaiming storage for the rules left in chain->reap. 2618 */ 2619static void 2620free_chain(struct ip_fw_chain *chain, int kill_default) 2621{ 2622 struct ip_fw *prev, *rule; 2623 2624 IPFW_LOCK_ASSERT(chain); 2625 2626 flush_rule_ptrs(chain); /* more efficient to do outside the loop */ 2627 for (prev = NULL, rule = chain->rules; rule ; ) 2628 if (kill_default || rule->set != RESVD_SET) 2629 rule = remove_rule(chain, rule, prev); 2630 else { 2631 prev = rule; 2632 rule = rule->next; 2633 } 2634} 2635 2636/** 2637 * Remove all rules with given number, and also do set manipulation. 2638 * Assumes chain != NULL && *chain != NULL. 2639 * 2640 * The argument is an u_int32_t. The low 16 bit are the rule or set number, 2641 * the next 8 bits are the new set, the top 8 bits are the command: 2642 * 2643 * 0 delete rules with given number 2644 * 1 delete rules with given set number 2645 * 2 move rules with given number to new set 2646 * 3 move rules with given set number to new set 2647 * 4 swap sets with given numbers 2648 */ 2649static int 2650del_entry(struct ip_fw_chain *chain, u_int32_t arg) 2651{ 2652 struct ip_fw *prev = NULL, *rule; 2653 u_int16_t rulenum; /* rule or old_set */ 2654 u_int8_t cmd, new_set; 2655 2656 rulenum = arg & 0xffff; 2657 cmd = (arg >> 24) & 0xff; 2658 new_set = (arg >> 16) & 0xff; 2659 2660 if (cmd > 4) 2661 return EINVAL; 2662 if (new_set > RESVD_SET) 2663 return EINVAL; 2664 if (cmd == 0 || cmd == 2) { 2665 if (rulenum >= IPFW_DEFAULT_RULE) 2666 return EINVAL; 2667 } else { 2668 if (rulenum > RESVD_SET) /* old_set */ 2669 return EINVAL; 2670 } 2671 2672 IPFW_LOCK(chain); 2673 rule = chain->rules; 2674 chain->reap = NULL; 2675 switch (cmd) { 2676 case 0: /* delete rules with given number */ 2677 /* 2678 * locate first rule to delete 2679 */ 2680 for (; rule->rulenum < rulenum; prev = rule, rule = rule->next) 2681 ; 2682 if (rule->rulenum != rulenum) { 2683 IPFW_UNLOCK(chain); 2684 return EINVAL; 2685 } 2686 2687 /* 2688 * flush pointers outside the loop, then delete all matching 2689 * rules. prev remains the same throughout the cycle. 2690 */ 2691 flush_rule_ptrs(chain); 2692 while (rule->rulenum == rulenum) 2693 rule = remove_rule(chain, rule, prev); 2694 break; 2695 2696 case 1: /* delete all rules with given set number */ 2697 flush_rule_ptrs(chain); 2698 rule = chain->rules; 2699 while (rule->rulenum < IPFW_DEFAULT_RULE) 2700 if (rule->set == rulenum) 2701 rule = remove_rule(chain, rule, prev); 2702 else { 2703 prev = rule; 2704 rule = rule->next; 2705 } 2706 break; 2707 2708 case 2: /* move rules with given number to new set */ 2709 rule = chain->rules; 2710 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2711 if (rule->rulenum == rulenum) 2712 rule->set = new_set; 2713 break; 2714 2715 case 3: /* move rules with given set number to new set */ 2716 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2717 if (rule->set == rulenum) 2718 rule->set = new_set; 2719 break; 2720 2721 case 4: /* swap two sets */ 2722 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2723 if (rule->set == rulenum) 2724 rule->set = new_set; 2725 else if (rule->set == new_set) 2726 rule->set = rulenum; 2727 break; 2728 } 2729 /* 2730 * Look for rules to reclaim. We grab the list before 2731 * releasing the lock then reclaim them w/o the lock to 2732 * avoid a LOR with dummynet. 2733 */ 2734 rule = chain->reap; 2735 chain->reap = NULL; 2736 IPFW_UNLOCK(chain); 2737 if (rule) 2738 reap_rules(rule); 2739 return 0; 2740} 2741 2742/* 2743 * Clear counters for a specific rule. 2744 * The enclosing "table" is assumed locked. 2745 */ 2746static void 2747clear_counters(struct ip_fw *rule, int log_only) 2748{ 2749 ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule); 2750 2751 if (log_only == 0) { 2752 rule->bcnt = rule->pcnt = 0; 2753 rule->timestamp = 0; 2754 } 2755 if (l->o.opcode == O_LOG) 2756 l->log_left = l->max_log; 2757} 2758 2759/** 2760 * Reset some or all counters on firewall rules. 2761 * @arg frwl is null to clear all entries, or contains a specific 2762 * rule number. 2763 * @arg log_only is 1 if we only want to reset logs, zero otherwise. 2764 */ 2765static int 2766zero_entry(struct ip_fw_chain *chain, int rulenum, int log_only) 2767{ 2768 struct ip_fw *rule; 2769 char *msg; 2770 2771 IPFW_LOCK(chain); 2772 if (rulenum == 0) { 2773 norule_counter = 0; 2774 for (rule = chain->rules; rule; rule = rule->next) 2775 clear_counters(rule, log_only); 2776 msg = log_only ? "ipfw: All logging counts reset.\n" : 2777 "ipfw: Accounting cleared.\n"; 2778 } else { 2779 int cleared = 0; 2780 /* 2781 * We can have multiple rules with the same number, so we 2782 * need to clear them all. 2783 */ 2784 for (rule = chain->rules; rule; rule = rule->next) 2785 if (rule->rulenum == rulenum) { 2786 while (rule && rule->rulenum == rulenum) { 2787 clear_counters(rule, log_only); 2788 rule = rule->next; 2789 } 2790 cleared = 1; 2791 break; 2792 } 2793 if (!cleared) { /* we did not find any matching rules */ 2794 IPFW_UNLOCK(chain); 2795 return (EINVAL); 2796 } 2797 msg = log_only ? "ipfw: Entry %d logging count reset.\n" : 2798 "ipfw: Entry %d cleared.\n"; 2799 } 2800 IPFW_UNLOCK(chain); 2801 2802 if (fw_verbose) 2803 log(LOG_SECURITY | LOG_NOTICE, msg, rulenum); 2804 return (0); 2805} 2806 2807/* 2808 * Check validity of the structure before insert. 2809 * Fortunately rules are simple, so this mostly need to check rule sizes. 2810 */ 2811static int 2812check_ipfw_struct(struct ip_fw *rule, int size) 2813{ 2814 int l, cmdlen = 0; 2815 int have_action=0; 2816 ipfw_insn *cmd; 2817 2818 if (size < sizeof(*rule)) { 2819 printf("ipfw: rule too short\n"); 2820 return (EINVAL); 2821 } 2822 /* first, check for valid size */ 2823 l = RULESIZE(rule); 2824 if (l != size) { 2825 printf("ipfw: size mismatch (have %d want %d)\n", size, l); 2826 return (EINVAL); 2827 } 2828 /* 2829 * Now go for the individual checks. Very simple ones, basically only 2830 * instruction sizes. 2831 */ 2832 for (l = rule->cmd_len, cmd = rule->cmd ; 2833 l > 0 ; l -= cmdlen, cmd += cmdlen) { 2834 cmdlen = F_LEN(cmd); 2835 if (cmdlen > l) { 2836 printf("ipfw: opcode %d size truncated\n", 2837 cmd->opcode); 2838 return EINVAL; 2839 } 2840 DEB(printf("ipfw: opcode %d\n", cmd->opcode);) 2841 switch (cmd->opcode) { 2842 case O_PROBE_STATE: 2843 case O_KEEP_STATE: 2844 case O_PROTO: 2845 case O_IP_SRC_ME: 2846 case O_IP_DST_ME: 2847 case O_LAYER2: 2848 case O_IN: 2849 case O_FRAG: 2850 case O_IPOPT: 2851 case O_IPTOS: 2852 case O_IPPRECEDENCE: 2853 case O_IPVER: 2854 case O_TCPWIN: 2855 case O_TCPFLAGS: 2856 case O_TCPOPTS: 2857 case O_ESTAB: 2858 case O_VERREVPATH: 2859 case O_VERSRCREACH: 2860 case O_ANTISPOOF: 2861 case O_IPSEC: 2862 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 2863 goto bad_size; 2864 break; 2865 2866 case O_UID: 2867 case O_GID: 2868 case O_JAIL: 2869 case O_IP_SRC: 2870 case O_IP_DST: 2871 case O_TCPSEQ: 2872 case O_TCPACK: 2873 case O_PROB: 2874 case O_ICMPTYPE: 2875 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 2876 goto bad_size; 2877 break; 2878 2879 case O_LIMIT: 2880 if (cmdlen != F_INSN_SIZE(ipfw_insn_limit)) 2881 goto bad_size; 2882 break; 2883 2884 case O_LOG: 2885 if (cmdlen != F_INSN_SIZE(ipfw_insn_log)) 2886 goto bad_size; 2887 2888 ((ipfw_insn_log *)cmd)->log_left = 2889 ((ipfw_insn_log *)cmd)->max_log; 2890 2891 break; 2892 2893 case O_IP_SRC_MASK: 2894 case O_IP_DST_MASK: 2895 /* only odd command lengths */ 2896 if ( !(cmdlen & 1) || cmdlen > 31) 2897 goto bad_size; 2898 break; 2899 2900 case O_IP_SRC_SET: 2901 case O_IP_DST_SET: 2902 if (cmd->arg1 == 0 || cmd->arg1 > 256) { 2903 printf("ipfw: invalid set size %d\n", 2904 cmd->arg1); 2905 return EINVAL; 2906 } 2907 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 2908 (cmd->arg1+31)/32 ) 2909 goto bad_size; 2910 break; 2911 2912 case O_IP_SRC_LOOKUP: 2913 case O_IP_DST_LOOKUP: 2914 if (cmd->arg1 >= IPFW_TABLES_MAX) { 2915 printf("ipfw: invalid table number %d\n", 2916 cmd->arg1); 2917 return (EINVAL); 2918 } 2919 if (cmdlen != F_INSN_SIZE(ipfw_insn) && 2920 cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 2921 goto bad_size; 2922 break; 2923 2924 case O_MACADDR2: 2925 if (cmdlen != F_INSN_SIZE(ipfw_insn_mac)) 2926 goto bad_size; 2927 break; 2928 2929 case O_NOP: 2930 case O_IPID: 2931 case O_IPTTL: 2932 case O_IPLEN: 2933 if (cmdlen < 1 || cmdlen > 31) 2934 goto bad_size; 2935 break; 2936 2937 case O_MAC_TYPE: 2938 case O_IP_SRCPORT: 2939 case O_IP_DSTPORT: /* XXX artificial limit, 30 port pairs */ 2940 if (cmdlen < 2 || cmdlen > 31) 2941 goto bad_size; 2942 break; 2943 2944 case O_RECV: 2945 case O_XMIT: 2946 case O_VIA: 2947 if (cmdlen != F_INSN_SIZE(ipfw_insn_if)) 2948 goto bad_size; 2949 break; 2950 2951 case O_PIPE: 2952 case O_QUEUE: 2953 if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe)) 2954 goto bad_size; 2955 goto check_action; 2956 2957 case O_FORWARD_IP: 2958 if (cmdlen != F_INSN_SIZE(ipfw_insn_sa)) 2959 goto bad_size; 2960 goto check_action; 2961 2962 case O_FORWARD_MAC: /* XXX not implemented yet */ 2963 case O_CHECK_STATE: 2964 case O_COUNT: 2965 case O_ACCEPT: 2966 case O_DENY: 2967 case O_REJECT: 2968 case O_SKIPTO: 2969 case O_DIVERT: 2970 case O_TEE: 2971 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 2972 goto bad_size; 2973check_action: 2974 if (have_action) { 2975 printf("ipfw: opcode %d, multiple actions" 2976 " not allowed\n", 2977 cmd->opcode); 2978 return EINVAL; 2979 } 2980 have_action = 1; 2981 if (l != cmdlen) { 2982 printf("ipfw: opcode %d, action must be" 2983 " last opcode\n", 2984 cmd->opcode); 2985 return EINVAL; 2986 } 2987 break; 2988 default: 2989 printf("ipfw: opcode %d, unknown opcode\n", 2990 cmd->opcode); 2991 return EINVAL; 2992 } 2993 } 2994 if (have_action == 0) { 2995 printf("ipfw: missing action\n"); 2996 return EINVAL; 2997 } 2998 return 0; 2999 3000bad_size: 3001 printf("ipfw: opcode %d size %d wrong\n", 3002 cmd->opcode, cmdlen); 3003 return EINVAL; 3004} 3005 3006/* 3007 * Copy the static and dynamic rules to the supplied buffer 3008 * and return the amount of space actually used. 3009 */ 3010static size_t 3011ipfw_getrules(struct ip_fw_chain *chain, void *buf, size_t space) 3012{ 3013 char *bp = buf; 3014 char *ep = bp + space; 3015 struct ip_fw *rule; 3016 int i; 3017 3018 /* XXX this can take a long time and locking will block packet flow */ 3019 IPFW_LOCK(chain); 3020 for (rule = chain->rules; rule ; rule = rule->next) { 3021 /* 3022 * Verify the entry fits in the buffer in case the 3023 * rules changed between calculating buffer space and 3024 * now. This would be better done using a generation 3025 * number but should suffice for now. 3026 */ 3027 i = RULESIZE(rule); 3028 if (bp + i <= ep) { 3029 bcopy(rule, bp, i); 3030 bcopy(&set_disable, &(((struct ip_fw *)bp)->next_rule), 3031 sizeof(set_disable)); 3032 bp += i; 3033 } 3034 } 3035 IPFW_UNLOCK(chain); 3036 if (ipfw_dyn_v) { 3037 ipfw_dyn_rule *p, *last = NULL; 3038 3039 IPFW_DYN_LOCK(); 3040 for (i = 0 ; i < curr_dyn_buckets; i++) 3041 for (p = ipfw_dyn_v[i] ; p != NULL; p = p->next) { 3042 if (bp + sizeof *p <= ep) { 3043 ipfw_dyn_rule *dst = 3044 (ipfw_dyn_rule *)bp; 3045 bcopy(p, dst, sizeof *p); 3046 bcopy(&(p->rule->rulenum), &(dst->rule), 3047 sizeof(p->rule->rulenum)); 3048 /* 3049 * store a non-null value in "next". 3050 * The userland code will interpret a 3051 * NULL here as a marker 3052 * for the last dynamic rule. 3053 */ 3054 bcopy(&dst, &dst->next, sizeof(dst)); 3055 last = dst; 3056 dst->expire = 3057 TIME_LEQ(dst->expire, time_second) ? 3058 0 : dst->expire - time_second ; 3059 bp += sizeof(ipfw_dyn_rule); 3060 } 3061 } 3062 IPFW_DYN_UNLOCK(); 3063 if (last != NULL) /* mark last dynamic rule */ 3064 bzero(&last->next, sizeof(last)); 3065 } 3066 return (bp - (char *)buf); 3067} 3068 3069 3070/** 3071 * {set|get}sockopt parser. 3072 */ 3073static int 3074ipfw_ctl(struct sockopt *sopt) 3075{ 3076#define RULE_MAXSIZE (256*sizeof(u_int32_t)) 3077 int error, rule_num; 3078 size_t size; 3079 struct ip_fw *buf, *rule; 3080 u_int32_t rulenum[2]; 3081 3082 error = suser(sopt->sopt_td); 3083 if (error) 3084 return (error); 3085 3086 /* 3087 * Disallow modifications in really-really secure mode, but still allow 3088 * the logging counters to be reset. 3089 */ 3090 if (sopt->sopt_name == IP_FW_ADD || 3091 (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) { 3092#if __FreeBSD_version >= 500034 3093 error = securelevel_ge(sopt->sopt_td->td_ucred, 3); 3094 if (error) 3095 return (error); 3096#else /* FreeBSD 4.x */ 3097 if (securelevel >= 3) 3098 return (EPERM); 3099#endif 3100 } 3101 3102 error = 0; 3103 3104 switch (sopt->sopt_name) { 3105 case IP_FW_GET: 3106 /* 3107 * pass up a copy of the current rules. Static rules 3108 * come first (the last of which has number IPFW_DEFAULT_RULE), 3109 * followed by a possibly empty list of dynamic rule. 3110 * The last dynamic rule has NULL in the "next" field. 3111 * 3112 * Note that the calculated size is used to bound the 3113 * amount of data returned to the user. The rule set may 3114 * change between calculating the size and returning the 3115 * data in which case we'll just return what fits. 3116 */ 3117 size = static_len; /* size of static rules */ 3118 if (ipfw_dyn_v) /* add size of dyn.rules */ 3119 size += (dyn_count * sizeof(ipfw_dyn_rule)); 3120 3121 /* 3122 * XXX todo: if the user passes a short length just to know 3123 * how much room is needed, do not bother filling up the 3124 * buffer, just jump to the sooptcopyout. 3125 */ 3126 buf = malloc(size, M_TEMP, M_WAITOK); 3127 error = sooptcopyout(sopt, buf, 3128 ipfw_getrules(&layer3_chain, buf, size)); 3129 free(buf, M_TEMP); 3130 break; 3131 3132 case IP_FW_FLUSH: 3133 /* 3134 * Normally we cannot release the lock on each iteration. 3135 * We could do it here only because we start from the head all 3136 * the times so there is no risk of missing some entries. 3137 * On the other hand, the risk is that we end up with 3138 * a very inconsistent ruleset, so better keep the lock 3139 * around the whole cycle. 3140 * 3141 * XXX this code can be improved by resetting the head of 3142 * the list to point to the default rule, and then freeing 3143 * the old list without the need for a lock. 3144 */ 3145 3146 IPFW_LOCK(&layer3_chain); 3147 layer3_chain.reap = NULL; 3148 free_chain(&layer3_chain, 0 /* keep default rule */); 3149 rule = layer3_chain.reap, layer3_chain.reap = NULL; 3150 IPFW_UNLOCK(&layer3_chain); 3151 if (layer3_chain.reap != NULL) 3152 reap_rules(rule); 3153 break; 3154 3155 case IP_FW_ADD: 3156 rule = malloc(RULE_MAXSIZE, M_TEMP, M_WAITOK); 3157 error = sooptcopyin(sopt, rule, RULE_MAXSIZE, 3158 sizeof(struct ip_fw) ); 3159 if (error == 0) 3160 error = check_ipfw_struct(rule, sopt->sopt_valsize); 3161 if (error == 0) { 3162 error = add_rule(&layer3_chain, rule); 3163 size = RULESIZE(rule); 3164 if (!error && sopt->sopt_dir == SOPT_GET) 3165 error = sooptcopyout(sopt, rule, size); 3166 } 3167 free(rule, M_TEMP); 3168 break; 3169 3170 case IP_FW_DEL: 3171 /* 3172 * IP_FW_DEL is used for deleting single rules or sets, 3173 * and (ab)used to atomically manipulate sets. Argument size 3174 * is used to distinguish between the two: 3175 * sizeof(u_int32_t) 3176 * delete single rule or set of rules, 3177 * or reassign rules (or sets) to a different set. 3178 * 2*sizeof(u_int32_t) 3179 * atomic disable/enable sets. 3180 * first u_int32_t contains sets to be disabled, 3181 * second u_int32_t contains sets to be enabled. 3182 */ 3183 error = sooptcopyin(sopt, rulenum, 3184 2*sizeof(u_int32_t), sizeof(u_int32_t)); 3185 if (error) 3186 break; 3187 size = sopt->sopt_valsize; 3188 if (size == sizeof(u_int32_t)) /* delete or reassign */ 3189 error = del_entry(&layer3_chain, rulenum[0]); 3190 else if (size == 2*sizeof(u_int32_t)) /* set enable/disable */ 3191 set_disable = 3192 (set_disable | rulenum[0]) & ~rulenum[1] & 3193 ~(1<<RESVD_SET); /* set RESVD_SET always enabled */ 3194 else 3195 error = EINVAL; 3196 break; 3197 3198 case IP_FW_ZERO: 3199 case IP_FW_RESETLOG: /* argument is an int, the rule number */ 3200 rule_num = 0; 3201 if (sopt->sopt_val != 0) { 3202 error = sooptcopyin(sopt, &rule_num, 3203 sizeof(int), sizeof(int)); 3204 if (error) 3205 break; 3206 } 3207 error = zero_entry(&layer3_chain, rule_num, 3208 sopt->sopt_name == IP_FW_RESETLOG); 3209 break; 3210 3211 case IP_FW_TABLE_ADD: 3212 { 3213 ipfw_table_entry ent; 3214 3215 error = sooptcopyin(sopt, &ent, 3216 sizeof(ent), sizeof(ent)); 3217 if (error) 3218 break; 3219 error = add_table_entry(ent.tbl, ent.addr, 3220 ent.masklen, ent.value); 3221 } 3222 break; 3223 3224 case IP_FW_TABLE_DEL: 3225 { 3226 ipfw_table_entry ent; 3227 3228 error = sooptcopyin(sopt, &ent, 3229 sizeof(ent), sizeof(ent)); 3230 if (error) 3231 break; 3232 error = del_table_entry(ent.tbl, ent.addr, ent.masklen); 3233 } 3234 break; 3235 3236 case IP_FW_TABLE_FLUSH: 3237 { 3238 u_int16_t tbl; 3239 3240 error = sooptcopyin(sopt, &tbl, 3241 sizeof(tbl), sizeof(tbl)); 3242 if (error) 3243 break; 3244 error = flush_table(tbl); 3245 } 3246 break; 3247 3248 case IP_FW_TABLE_GETSIZE: 3249 { 3250 u_int32_t tbl, cnt; 3251 3252 if ((error = sooptcopyin(sopt, &tbl, sizeof(tbl), 3253 sizeof(tbl)))) 3254 break; 3255 if ((error = count_table(tbl, &cnt))) 3256 break; 3257 error = sooptcopyout(sopt, &cnt, sizeof(cnt)); 3258 } 3259 break; 3260 3261 case IP_FW_TABLE_LIST: 3262 { 3263 ipfw_table *tbl; 3264 3265 if (sopt->sopt_valsize < sizeof(*tbl)) { 3266 error = EINVAL; 3267 break; 3268 } 3269 size = sopt->sopt_valsize; 3270 tbl = malloc(size, M_TEMP, M_WAITOK); 3271 if (tbl == NULL) { 3272 error = ENOMEM; 3273 break; 3274 } 3275 error = sooptcopyin(sopt, tbl, size, sizeof(*tbl)); 3276 if (error) { 3277 free(tbl, M_TEMP); 3278 break; 3279 } 3280 tbl->size = (size - sizeof(*tbl)) / 3281 sizeof(ipfw_table_entry); 3282 error = dump_table(tbl); 3283 if (error) { 3284 free(tbl, M_TEMP); 3285 break; 3286 } 3287 error = sooptcopyout(sopt, tbl, size); 3288 free(tbl, M_TEMP); 3289 } 3290 break; 3291 3292 default: 3293 printf("ipfw: ipfw_ctl invalid option %d\n", sopt->sopt_name); 3294 error = EINVAL; 3295 } 3296 3297 return (error); 3298#undef RULE_MAXSIZE 3299} 3300 3301/** 3302 * dummynet needs a reference to the default rule, because rules can be 3303 * deleted while packets hold a reference to them. When this happens, 3304 * dummynet changes the reference to the default rule (it could well be a 3305 * NULL pointer, but this way we do not need to check for the special 3306 * case, plus here he have info on the default behaviour). 3307 */ 3308struct ip_fw *ip_fw_default_rule; 3309 3310/* 3311 * This procedure is only used to handle keepalives. It is invoked 3312 * every dyn_keepalive_period 3313 */ 3314static void 3315ipfw_tick(void * __unused unused) 3316{ 3317 int i; 3318 ipfw_dyn_rule *q; 3319 3320 if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0) 3321 goto done; 3322 3323 IPFW_DYN_LOCK(); 3324 for (i = 0 ; i < curr_dyn_buckets ; i++) { 3325 for (q = ipfw_dyn_v[i] ; q ; q = q->next ) { 3326 if (q->dyn_type == O_LIMIT_PARENT) 3327 continue; 3328 if (q->id.proto != IPPROTO_TCP) 3329 continue; 3330 if ( (q->state & BOTH_SYN) != BOTH_SYN) 3331 continue; 3332 if (TIME_LEQ( time_second+dyn_keepalive_interval, 3333 q->expire)) 3334 continue; /* too early */ 3335 if (TIME_LEQ(q->expire, time_second)) 3336 continue; /* too late, rule expired */ 3337 3338 send_pkt(&(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 3339 send_pkt(&(q->id), q->ack_fwd - 1, q->ack_rev, 0); 3340 } 3341 } 3342 IPFW_DYN_UNLOCK(); 3343done: 3344 callout_reset(&ipfw_timeout, dyn_keepalive_period*hz, ipfw_tick, NULL); 3345} 3346 3347int 3348ipfw_init(void) 3349{ 3350 struct ip_fw default_rule; 3351 int error; 3352 3353 layer3_chain.rules = NULL; 3354 IPFW_LOCK_INIT(&layer3_chain); 3355 IPFW_DYN_LOCK_INIT(); 3356 callout_init(&ipfw_timeout, debug_mpsafenet ? CALLOUT_MPSAFE : 0); 3357 3358 bzero(&default_rule, sizeof default_rule); 3359 3360 default_rule.act_ofs = 0; 3361 default_rule.rulenum = IPFW_DEFAULT_RULE; 3362 default_rule.cmd_len = 1; 3363 default_rule.set = RESVD_SET; 3364 3365 default_rule.cmd[0].len = 1; 3366 default_rule.cmd[0].opcode = 3367#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 3368 1 ? O_ACCEPT : 3369#endif 3370 O_DENY; 3371 3372 error = add_rule(&layer3_chain, &default_rule); 3373 if (error != 0) { 3374 printf("ipfw2: error %u initializing default rule " 3375 "(support disabled)\n", error); 3376 IPFW_DYN_LOCK_DESTROY(); 3377 IPFW_LOCK_DESTROY(&layer3_chain); 3378 return (error); 3379 } 3380 3381 ip_fw_default_rule = layer3_chain.rules; 3382 printf("ipfw2 initialized, divert %s, " 3383 "rule-based forwarding " 3384#ifdef IPFIREWALL_FORWARD 3385 "enabled, " 3386#else 3387 "disabled, " 3388#endif 3389 "default to %s, logging ", 3390#ifdef IPDIVERT 3391 "enabled", 3392#else 3393 "disabled", 3394#endif 3395 default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny"); 3396 3397#ifdef IPFIREWALL_VERBOSE 3398 fw_verbose = 1; 3399#endif 3400#ifdef IPFIREWALL_VERBOSE_LIMIT 3401 verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 3402#endif 3403 if (fw_verbose == 0) 3404 printf("disabled\n"); 3405 else if (verbose_limit == 0) 3406 printf("unlimited\n"); 3407 else 3408 printf("limited to %d packets/entry by default\n", 3409 verbose_limit); 3410 3411 init_tables(); 3412 ip_fw_ctl_ptr = ipfw_ctl; 3413 ip_fw_chk_ptr = ipfw_chk; 3414 callout_reset(&ipfw_timeout, hz, ipfw_tick, NULL); 3415 3416 return (0); 3417} 3418 3419void 3420ipfw_destroy(void) 3421{ 3422 struct ip_fw *reap; 3423 3424 ip_fw_chk_ptr = NULL; 3425 ip_fw_ctl_ptr = NULL; 3426 IPFW_LOCK(&layer3_chain); 3427 callout_stop(&ipfw_timeout); 3428 layer3_chain.reap = NULL; 3429 free_chain(&layer3_chain, 1 /* kill default rule */); 3430 reap = layer3_chain.reap, layer3_chain.reap = NULL; 3431 IPFW_UNLOCK(&layer3_chain); 3432 if (reap != NULL) 3433 reap_rules(reap); 3434 flush_tables(); 3435 IPFW_DYN_LOCK_DESTROY(); 3436 IPFW_LOCK_DESTROY(&layer3_chain); 3437 printf("IP firewall unloaded\n"); 3438} 3439 3440#endif /* IPFW2 */ 3441