ip_fw2.c revision 135977
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 135977 2004-09-30 17:42:00Z green $ 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 void 1536fill_ugid_cache(struct inpcb *inp, struct ip_fw_ugid *ugp) 1537{ 1538 struct ucred *cr; 1539 1540 if (inp->inp_socket != NULL) { 1541 cr = inp->inp_socket->so_cred; 1542 ugp->fw_prid = jailed(cr) ? 1543 cr->cr_prison->pr_id : -1; 1544 ugp->fw_uid = cr->cr_uid; 1545 ugp->fw_ngroups = cr->cr_ngroups; 1546 bcopy(cr->cr_groups, ugp->fw_groups, 1547 sizeof(ugp->fw_groups)); 1548 } 1549} 1550 1551static int 1552check_uidgid(ipfw_insn_u32 *insn, 1553 int proto, struct ifnet *oif, 1554 struct in_addr dst_ip, u_int16_t dst_port, 1555 struct in_addr src_ip, u_int16_t src_port, 1556 struct ip_fw_ugid *ugp, int *lookup, struct inpcb *inp) 1557{ 1558 struct inpcbinfo *pi; 1559 int wildcard; 1560 struct inpcb *pcb; 1561 int match; 1562 gid_t *gp; 1563 1564 /* 1565 * Check to see if the UDP or TCP stack supplied us with 1566 * the PCB. If so, rather then holding a lock and looking 1567 * up the PCB, we can use the one that was supplied. 1568 */ 1569 if (inp && *lookup == 0) { 1570 INP_LOCK_ASSERT(inp); 1571 if (inp->inp_socket != NULL) { 1572 fill_ugid_cache(inp, ugp); 1573 *lookup = 1; 1574 } 1575 } 1576 /* 1577 * If we have already been here and the packet has no 1578 * PCB entry associated with it, then we can safely 1579 * assume that this is a no match. 1580 */ 1581 if (*lookup == -1) 1582 return (0); 1583 if (proto == IPPROTO_TCP) { 1584 wildcard = 0; 1585 pi = &tcbinfo; 1586 } else if (proto == IPPROTO_UDP) { 1587 wildcard = 1; 1588 pi = &udbinfo; 1589 } else 1590 return 0; 1591 match = 0; 1592 if (*lookup == 0) { 1593 INP_INFO_RLOCK(pi); 1594 pcb = (oif) ? 1595 in_pcblookup_hash(pi, 1596 dst_ip, htons(dst_port), 1597 src_ip, htons(src_port), 1598 wildcard, oif) : 1599 in_pcblookup_hash(pi, 1600 src_ip, htons(src_port), 1601 dst_ip, htons(dst_port), 1602 wildcard, NULL); 1603 if (pcb != NULL) { 1604 INP_LOCK(pcb); 1605 if (pcb->inp_socket != NULL) { 1606 fill_ugid_cache(pcb, ugp); 1607 *lookup = 1; 1608 } 1609 INP_UNLOCK(pcb); 1610 } 1611 INP_INFO_RUNLOCK(pi); 1612 if (*lookup == 0) { 1613 /* 1614 * If the lookup did not yield any results, there 1615 * is no sense in coming back and trying again. So 1616 * we can set lookup to -1 and ensure that we wont 1617 * bother the pcb system again. 1618 */ 1619 *lookup = -1; 1620 return (0); 1621 } 1622 } 1623 if (insn->o.opcode == O_UID) 1624 match = (ugp->fw_uid == (uid_t)insn->d[0]); 1625 else if (insn->o.opcode == O_GID) { 1626 for (gp = ugp->fw_groups; 1627 gp < &ugp->fw_groups[ugp->fw_ngroups]; gp++) 1628 if (*gp == (gid_t)insn->d[0]) { 1629 match = 1; 1630 break; 1631 } 1632 } else if (insn->o.opcode == O_JAIL) 1633 match = (ugp->fw_prid == (int)insn->d[0]); 1634 return match; 1635} 1636 1637/* 1638 * The main check routine for the firewall. 1639 * 1640 * All arguments are in args so we can modify them and return them 1641 * back to the caller. 1642 * 1643 * Parameters: 1644 * 1645 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 1646 * Starts with the IP header. 1647 * args->eh (in) Mac header if present, or NULL for layer3 packet. 1648 * args->oif Outgoing interface, or NULL if packet is incoming. 1649 * The incoming interface is in the mbuf. (in) 1650 * args->divert_rule (in/out) 1651 * Skip up to the first rule past this rule number; 1652 * upon return, non-zero port number for divert or tee. 1653 * 1654 * args->rule Pointer to the last matching rule (in/out) 1655 * args->next_hop Socket we are forwarding to (out). 1656 * args->f_id Addresses grabbed from the packet (out) 1657 * 1658 * Return value: 1659 * 1660 * IP_FW_PORT_DENY_FLAG the packet must be dropped. 1661 * 0 The packet is to be accepted and routed normally OR 1662 * the packet was denied/rejected and has been dropped; 1663 * in the latter case, *m is equal to NULL upon return. 1664 * port Divert the packet to port, with these caveats: 1665 * 1666 * - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead 1667 * of diverting it (ie, 'ipfw tee'). 1668 * 1669 * - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower 1670 * 16 bits as a dummynet pipe number instead of diverting 1671 */ 1672 1673int 1674ipfw_chk(struct ip_fw_args *args) 1675{ 1676 /* 1677 * Local variables hold state during the processing of a packet. 1678 * 1679 * IMPORTANT NOTE: to speed up the processing of rules, there 1680 * are some assumption on the values of the variables, which 1681 * are documented here. Should you change them, please check 1682 * the implementation of the various instructions to make sure 1683 * that they still work. 1684 * 1685 * args->eh The MAC header. It is non-null for a layer2 1686 * packet, it is NULL for a layer-3 packet. 1687 * 1688 * m | args->m Pointer to the mbuf, as received from the caller. 1689 * It may change if ipfw_chk() does an m_pullup, or if it 1690 * consumes the packet because it calls send_reject(). 1691 * XXX This has to change, so that ipfw_chk() never modifies 1692 * or consumes the buffer. 1693 * ip is simply an alias of the value of m, and it is kept 1694 * in sync with it (the packet is supposed to start with 1695 * the ip header). 1696 */ 1697 struct mbuf *m = args->m; 1698 struct ip *ip = mtod(m, struct ip *); 1699 1700 /* 1701 * For rules which contain uid/gid or jail constraints, cache 1702 * a copy of the users credentials after the pcb lookup has been 1703 * executed. This will speed up the processing of rules with 1704 * these types of constraints, as well as decrease contention 1705 * on pcb related locks. 1706 */ 1707 struct ip_fw_ugid fw_ugid_cache; 1708 int ugid_lookup = 0; 1709 1710 /* 1711 * oif | args->oif If NULL, ipfw_chk has been called on the 1712 * inbound path (ether_input, bdg_forward, ip_input). 1713 * If non-NULL, ipfw_chk has been called on the outbound path 1714 * (ether_output, ip_output). 1715 */ 1716 struct ifnet *oif = args->oif; 1717 1718 struct ip_fw *f = NULL; /* matching rule */ 1719 int retval = 0; 1720 1721 /* 1722 * hlen The length of the IPv4 header. 1723 * hlen >0 means we have an IPv4 packet. 1724 */ 1725 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 1726 1727 /* 1728 * offset The offset of a fragment. offset != 0 means that 1729 * we have a fragment at this offset of an IPv4 packet. 1730 * offset == 0 means that (if this is an IPv4 packet) 1731 * this is the first or only fragment. 1732 */ 1733 u_short offset = 0; 1734 1735 /* 1736 * Local copies of addresses. They are only valid if we have 1737 * an IP packet. 1738 * 1739 * proto The protocol. Set to 0 for non-ip packets, 1740 * or to the protocol read from the packet otherwise. 1741 * proto != 0 means that we have an IPv4 packet. 1742 * 1743 * src_port, dst_port port numbers, in HOST format. Only 1744 * valid for TCP and UDP packets. 1745 * 1746 * src_ip, dst_ip ip addresses, in NETWORK format. 1747 * Only valid for IPv4 packets. 1748 */ 1749 u_int8_t proto; 1750 u_int16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 1751 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 1752 u_int16_t ip_len=0; 1753 int pktlen; 1754 int dyn_dir = MATCH_UNKNOWN; 1755 ipfw_dyn_rule *q = NULL; 1756 struct ip_fw_chain *chain = &layer3_chain; 1757 struct m_tag *mtag; 1758 1759 if (m->m_flags & M_SKIP_FIREWALL) 1760 return 0; /* accept */ 1761 /* 1762 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 1763 * MATCH_NONE when checked and not matched (q = NULL), 1764 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 1765 */ 1766 1767 pktlen = m->m_pkthdr.len; 1768 if (args->eh == NULL || /* layer 3 packet */ 1769 ( m->m_pkthdr.len >= sizeof(struct ip) && 1770 ntohs(args->eh->ether_type) == ETHERTYPE_IP)) 1771 hlen = ip->ip_hl << 2; 1772 1773 /* 1774 * Collect parameters into local variables for faster matching. 1775 */ 1776 if (hlen == 0) { /* do not grab addresses for non-ip pkts */ 1777 proto = args->f_id.proto = 0; /* mark f_id invalid */ 1778 goto after_ip_checks; 1779 } 1780 1781 proto = args->f_id.proto = ip->ip_p; 1782 src_ip = ip->ip_src; 1783 dst_ip = ip->ip_dst; 1784 if (args->eh != NULL) { /* layer 2 packets are as on the wire */ 1785 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1786 ip_len = ntohs(ip->ip_len); 1787 } else { 1788 offset = ip->ip_off & IP_OFFMASK; 1789 ip_len = ip->ip_len; 1790 } 1791 pktlen = ip_len < pktlen ? ip_len : pktlen; 1792 1793#define PULLUP_TO(len) \ 1794 do { \ 1795 if ((m)->m_len < (len)) { \ 1796 args->m = m = m_pullup(m, (len)); \ 1797 if (m == 0) \ 1798 goto pullup_failed; \ 1799 ip = mtod(m, struct ip *); \ 1800 } \ 1801 } while (0) 1802 1803 if (offset == 0) { 1804 switch (proto) { 1805 case IPPROTO_TCP: 1806 { 1807 struct tcphdr *tcp; 1808 1809 PULLUP_TO(hlen + sizeof(struct tcphdr)); 1810 tcp = L3HDR(struct tcphdr, ip); 1811 dst_port = tcp->th_dport; 1812 src_port = tcp->th_sport; 1813 args->f_id.flags = tcp->th_flags; 1814 } 1815 break; 1816 1817 case IPPROTO_UDP: 1818 { 1819 struct udphdr *udp; 1820 1821 PULLUP_TO(hlen + sizeof(struct udphdr)); 1822 udp = L3HDR(struct udphdr, ip); 1823 dst_port = udp->uh_dport; 1824 src_port = udp->uh_sport; 1825 } 1826 break; 1827 1828 case IPPROTO_ICMP: 1829 PULLUP_TO(hlen + 4); /* type, code and checksum. */ 1830 args->f_id.flags = L3HDR(struct icmp, ip)->icmp_type; 1831 break; 1832 1833 default: 1834 break; 1835 } 1836#undef PULLUP_TO 1837 } 1838 1839 args->f_id.src_ip = ntohl(src_ip.s_addr); 1840 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1841 args->f_id.src_port = src_port = ntohs(src_port); 1842 args->f_id.dst_port = dst_port = ntohs(dst_port); 1843 1844after_ip_checks: 1845 IPFW_LOCK(chain); /* XXX expensive? can we run lock free? */ 1846 mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL); 1847 if (args->rule) { 1848 /* 1849 * Packet has already been tagged. Look for the next rule 1850 * to restart processing. 1851 * 1852 * If fw_one_pass != 0 then just accept it. 1853 * XXX should not happen here, but optimized out in 1854 * the caller. 1855 */ 1856 if (fw_one_pass) { 1857 IPFW_UNLOCK(chain); /* XXX optimize */ 1858 return 0; 1859 } 1860 1861 f = args->rule->next_rule; 1862 if (f == NULL) 1863 f = lookup_next_rule(args->rule); 1864 } else { 1865 /* 1866 * Find the starting rule. It can be either the first 1867 * one, or the one after divert_rule if asked so. 1868 */ 1869 int skipto = mtag ? divert_cookie(mtag) : 0; 1870 1871 f = chain->rules; 1872 if (args->eh == NULL && skipto != 0) { 1873 if (skipto >= IPFW_DEFAULT_RULE) { 1874 IPFW_UNLOCK(chain); 1875 return(IP_FW_PORT_DENY_FLAG); /* invalid */ 1876 } 1877 while (f && f->rulenum <= skipto) 1878 f = f->next; 1879 if (f == NULL) { /* drop packet */ 1880 IPFW_UNLOCK(chain); 1881 return(IP_FW_PORT_DENY_FLAG); 1882 } 1883 } 1884 } 1885 /* reset divert rule to avoid confusion later */ 1886 if (mtag) 1887 m_tag_delete(m, mtag); 1888 1889 /* 1890 * Now scan the rules, and parse microinstructions for each rule. 1891 */ 1892 for (; f; f = f->next) { 1893 int l, cmdlen; 1894 ipfw_insn *cmd; 1895 int skip_or; /* skip rest of OR block */ 1896 1897again: 1898 if (set_disable & (1 << f->set) ) 1899 continue; 1900 1901 skip_or = 0; 1902 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1903 l -= cmdlen, cmd += cmdlen) { 1904 int match; 1905 1906 /* 1907 * check_body is a jump target used when we find a 1908 * CHECK_STATE, and need to jump to the body of 1909 * the target rule. 1910 */ 1911 1912check_body: 1913 cmdlen = F_LEN(cmd); 1914 /* 1915 * An OR block (insn_1 || .. || insn_n) has the 1916 * F_OR bit set in all but the last instruction. 1917 * The first match will set "skip_or", and cause 1918 * the following instructions to be skipped until 1919 * past the one with the F_OR bit clear. 1920 */ 1921 if (skip_or) { /* skip this instruction */ 1922 if ((cmd->len & F_OR) == 0) 1923 skip_or = 0; /* next one is good */ 1924 continue; 1925 } 1926 match = 0; /* set to 1 if we succeed */ 1927 1928 switch (cmd->opcode) { 1929 /* 1930 * The first set of opcodes compares the packet's 1931 * fields with some pattern, setting 'match' if a 1932 * match is found. At the end of the loop there is 1933 * logic to deal with F_NOT and F_OR flags associated 1934 * with the opcode. 1935 */ 1936 case O_NOP: 1937 match = 1; 1938 break; 1939 1940 case O_FORWARD_MAC: 1941 printf("ipfw: opcode %d unimplemented\n", 1942 cmd->opcode); 1943 break; 1944 1945 case O_GID: 1946 case O_UID: 1947 case O_JAIL: 1948 /* 1949 * We only check offset == 0 && proto != 0, 1950 * as this ensures that we have an IPv4 1951 * packet with the ports info. 1952 */ 1953 if (offset!=0) 1954 break; 1955 if (proto == IPPROTO_TCP || 1956 proto == IPPROTO_UDP) 1957 match = check_uidgid( 1958 (ipfw_insn_u32 *)cmd, 1959 proto, oif, 1960 dst_ip, dst_port, 1961 src_ip, src_port, &fw_ugid_cache, 1962 &ugid_lookup, args->inp); 1963 break; 1964 1965 case O_RECV: 1966 match = iface_match(m->m_pkthdr.rcvif, 1967 (ipfw_insn_if *)cmd); 1968 break; 1969 1970 case O_XMIT: 1971 match = iface_match(oif, (ipfw_insn_if *)cmd); 1972 break; 1973 1974 case O_VIA: 1975 match = iface_match(oif ? oif : 1976 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd); 1977 break; 1978 1979 case O_MACADDR2: 1980 if (args->eh != NULL) { /* have MAC header */ 1981 u_int32_t *want = (u_int32_t *) 1982 ((ipfw_insn_mac *)cmd)->addr; 1983 u_int32_t *mask = (u_int32_t *) 1984 ((ipfw_insn_mac *)cmd)->mask; 1985 u_int32_t *hdr = (u_int32_t *)args->eh; 1986 1987 match = 1988 ( want[0] == (hdr[0] & mask[0]) && 1989 want[1] == (hdr[1] & mask[1]) && 1990 want[2] == (hdr[2] & mask[2]) ); 1991 } 1992 break; 1993 1994 case O_MAC_TYPE: 1995 if (args->eh != NULL) { 1996 u_int16_t t = 1997 ntohs(args->eh->ether_type); 1998 u_int16_t *p = 1999 ((ipfw_insn_u16 *)cmd)->ports; 2000 int i; 2001 2002 for (i = cmdlen - 1; !match && i>0; 2003 i--, p += 2) 2004 match = (t>=p[0] && t<=p[1]); 2005 } 2006 break; 2007 2008 case O_FRAG: 2009 match = (hlen > 0 && offset != 0); 2010 break; 2011 2012 case O_IN: /* "out" is "not in" */ 2013 match = (oif == NULL); 2014 break; 2015 2016 case O_LAYER2: 2017 match = (args->eh != NULL); 2018 break; 2019 2020 case O_PROTO: 2021 /* 2022 * We do not allow an arg of 0 so the 2023 * check of "proto" only suffices. 2024 */ 2025 match = (proto == cmd->arg1); 2026 break; 2027 2028 case O_IP_SRC: 2029 match = (hlen > 0 && 2030 ((ipfw_insn_ip *)cmd)->addr.s_addr == 2031 src_ip.s_addr); 2032 break; 2033 2034 case O_IP_SRC_LOOKUP: 2035 case O_IP_DST_LOOKUP: 2036 if (hlen > 0) { 2037 uint32_t a = 2038 (cmd->opcode == O_IP_DST_LOOKUP) ? 2039 dst_ip.s_addr : src_ip.s_addr; 2040 uint32_t v; 2041 2042 match = lookup_table(cmd->arg1, a, &v); 2043 if (!match) 2044 break; 2045 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 2046 match = 2047 ((ipfw_insn_u32 *)cmd)->d[0] == v; 2048 } 2049 break; 2050 2051 case O_IP_SRC_MASK: 2052 case O_IP_DST_MASK: 2053 if (hlen > 0) { 2054 uint32_t a = 2055 (cmd->opcode == O_IP_DST_MASK) ? 2056 dst_ip.s_addr : src_ip.s_addr; 2057 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 2058 int i = cmdlen-1; 2059 2060 for (; !match && i>0; i-= 2, p+= 2) 2061 match = (p[0] == (a & p[1])); 2062 } 2063 break; 2064 2065 case O_IP_SRC_ME: 2066 if (hlen > 0) { 2067 struct ifnet *tif; 2068 2069 INADDR_TO_IFP(src_ip, tif); 2070 match = (tif != NULL); 2071 } 2072 break; 2073 2074 case O_IP_DST_SET: 2075 case O_IP_SRC_SET: 2076 if (hlen > 0) { 2077 u_int32_t *d = (u_int32_t *)(cmd+1); 2078 u_int32_t addr = 2079 cmd->opcode == O_IP_DST_SET ? 2080 args->f_id.dst_ip : 2081 args->f_id.src_ip; 2082 2083 if (addr < d[0]) 2084 break; 2085 addr -= d[0]; /* subtract base */ 2086 match = (addr < cmd->arg1) && 2087 ( d[ 1 + (addr>>5)] & 2088 (1<<(addr & 0x1f)) ); 2089 } 2090 break; 2091 2092 case O_IP_DST: 2093 match = (hlen > 0 && 2094 ((ipfw_insn_ip *)cmd)->addr.s_addr == 2095 dst_ip.s_addr); 2096 break; 2097 2098 case O_IP_DST_ME: 2099 if (hlen > 0) { 2100 struct ifnet *tif; 2101 2102 INADDR_TO_IFP(dst_ip, tif); 2103 match = (tif != NULL); 2104 } 2105 break; 2106 2107 case O_IP_SRCPORT: 2108 case O_IP_DSTPORT: 2109 /* 2110 * offset == 0 && proto != 0 is enough 2111 * to guarantee that we have an IPv4 2112 * packet with port info. 2113 */ 2114 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP) 2115 && offset == 0) { 2116 u_int16_t x = 2117 (cmd->opcode == O_IP_SRCPORT) ? 2118 src_port : dst_port ; 2119 u_int16_t *p = 2120 ((ipfw_insn_u16 *)cmd)->ports; 2121 int i; 2122 2123 for (i = cmdlen - 1; !match && i>0; 2124 i--, p += 2) 2125 match = (x>=p[0] && x<=p[1]); 2126 } 2127 break; 2128 2129 case O_ICMPTYPE: 2130 match = (offset == 0 && proto==IPPROTO_ICMP && 2131 icmptype_match(ip, (ipfw_insn_u32 *)cmd) ); 2132 break; 2133 2134 case O_IPOPT: 2135 match = (hlen > 0 && ipopts_match(ip, cmd) ); 2136 break; 2137 2138 case O_IPVER: 2139 match = (hlen > 0 && cmd->arg1 == ip->ip_v); 2140 break; 2141 2142 case O_IPID: 2143 case O_IPLEN: 2144 case O_IPTTL: 2145 if (hlen > 0) { /* only for IP packets */ 2146 uint16_t x; 2147 uint16_t *p; 2148 int i; 2149 2150 if (cmd->opcode == O_IPLEN) 2151 x = ip_len; 2152 else if (cmd->opcode == O_IPTTL) 2153 x = ip->ip_ttl; 2154 else /* must be IPID */ 2155 x = ntohs(ip->ip_id); 2156 if (cmdlen == 1) { 2157 match = (cmd->arg1 == x); 2158 break; 2159 } 2160 /* otherwise we have ranges */ 2161 p = ((ipfw_insn_u16 *)cmd)->ports; 2162 i = cmdlen - 1; 2163 for (; !match && i>0; i--, p += 2) 2164 match = (x >= p[0] && x <= p[1]); 2165 } 2166 break; 2167 2168 case O_IPPRECEDENCE: 2169 match = (hlen > 0 && 2170 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 2171 break; 2172 2173 case O_IPTOS: 2174 match = (hlen > 0 && 2175 flags_match(cmd, ip->ip_tos)); 2176 break; 2177 2178 case O_TCPFLAGS: 2179 match = (proto == IPPROTO_TCP && offset == 0 && 2180 flags_match(cmd, 2181 L3HDR(struct tcphdr,ip)->th_flags)); 2182 break; 2183 2184 case O_TCPOPTS: 2185 match = (proto == IPPROTO_TCP && offset == 0 && 2186 tcpopts_match(ip, cmd)); 2187 break; 2188 2189 case O_TCPSEQ: 2190 match = (proto == IPPROTO_TCP && offset == 0 && 2191 ((ipfw_insn_u32 *)cmd)->d[0] == 2192 L3HDR(struct tcphdr,ip)->th_seq); 2193 break; 2194 2195 case O_TCPACK: 2196 match = (proto == IPPROTO_TCP && offset == 0 && 2197 ((ipfw_insn_u32 *)cmd)->d[0] == 2198 L3HDR(struct tcphdr,ip)->th_ack); 2199 break; 2200 2201 case O_TCPWIN: 2202 match = (proto == IPPROTO_TCP && offset == 0 && 2203 cmd->arg1 == 2204 L3HDR(struct tcphdr,ip)->th_win); 2205 break; 2206 2207 case O_ESTAB: 2208 /* reject packets which have SYN only */ 2209 /* XXX should i also check for TH_ACK ? */ 2210 match = (proto == IPPROTO_TCP && offset == 0 && 2211 (L3HDR(struct tcphdr,ip)->th_flags & 2212 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 2213 break; 2214 2215 case O_LOG: 2216 if (fw_verbose) 2217 ipfw_log(f, hlen, args->eh, m, oif); 2218 match = 1; 2219 break; 2220 2221 case O_PROB: 2222 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 2223 break; 2224 2225 case O_VERREVPATH: 2226 /* Outgoing packets automatically pass/match */ 2227 match = (hlen > 0 && ((oif != NULL) || 2228 (m->m_pkthdr.rcvif == NULL) || 2229 verify_path(src_ip, m->m_pkthdr.rcvif))); 2230 break; 2231 2232 case O_VERSRCREACH: 2233 /* Outgoing packets automatically pass/match */ 2234 match = (hlen > 0 && ((oif != NULL) || 2235 verify_path(src_ip, NULL))); 2236 break; 2237 2238 case O_ANTISPOOF: 2239 /* Outgoing packets automatically pass/match */ 2240 if (oif == NULL && hlen > 0 && 2241 in_localaddr(src_ip)) 2242 match = verify_path(src_ip, 2243 m->m_pkthdr.rcvif); 2244 else 2245 match = 1; 2246 break; 2247 2248 case O_IPSEC: 2249#ifdef FAST_IPSEC 2250 match = (m_tag_find(m, 2251 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 2252#endif 2253#ifdef IPSEC 2254 match = (ipsec_getnhist(m) != 0); 2255#endif 2256 /* otherwise no match */ 2257 break; 2258 2259 /* 2260 * The second set of opcodes represents 'actions', 2261 * i.e. the terminal part of a rule once the packet 2262 * matches all previous patterns. 2263 * Typically there is only one action for each rule, 2264 * and the opcode is stored at the end of the rule 2265 * (but there are exceptions -- see below). 2266 * 2267 * In general, here we set retval and terminate the 2268 * outer loop (would be a 'break 3' in some language, 2269 * but we need to do a 'goto done'). 2270 * 2271 * Exceptions: 2272 * O_COUNT and O_SKIPTO actions: 2273 * instead of terminating, we jump to the next rule 2274 * ('goto next_rule', equivalent to a 'break 2'), 2275 * or to the SKIPTO target ('goto again' after 2276 * having set f, cmd and l), respectively. 2277 * 2278 * O_LIMIT and O_KEEP_STATE: these opcodes are 2279 * not real 'actions', and are stored right 2280 * before the 'action' part of the rule. 2281 * These opcodes try to install an entry in the 2282 * state tables; if successful, we continue with 2283 * the next opcode (match=1; break;), otherwise 2284 * the packet * must be dropped 2285 * ('goto done' after setting retval); 2286 * 2287 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 2288 * cause a lookup of the state table, and a jump 2289 * to the 'action' part of the parent rule 2290 * ('goto check_body') if an entry is found, or 2291 * (CHECK_STATE only) a jump to the next rule if 2292 * the entry is not found ('goto next_rule'). 2293 * The result of the lookup is cached to make 2294 * further instances of these opcodes are 2295 * effectively NOPs. 2296 */ 2297 case O_LIMIT: 2298 case O_KEEP_STATE: 2299 if (install_state(f, 2300 (ipfw_insn_limit *)cmd, args)) { 2301 retval = IP_FW_PORT_DENY_FLAG; 2302 goto done; /* error/limit violation */ 2303 } 2304 match = 1; 2305 break; 2306 2307 case O_PROBE_STATE: 2308 case O_CHECK_STATE: 2309 /* 2310 * dynamic rules are checked at the first 2311 * keep-state or check-state occurrence, 2312 * with the result being stored in dyn_dir. 2313 * The compiler introduces a PROBE_STATE 2314 * instruction for us when we have a 2315 * KEEP_STATE (because PROBE_STATE needs 2316 * to be run first). 2317 */ 2318 if (dyn_dir == MATCH_UNKNOWN && 2319 (q = lookup_dyn_rule(&args->f_id, 2320 &dyn_dir, proto == IPPROTO_TCP ? 2321 L3HDR(struct tcphdr, ip) : NULL)) 2322 != NULL) { 2323 /* 2324 * Found dynamic entry, update stats 2325 * and jump to the 'action' part of 2326 * the parent rule. 2327 */ 2328 q->pcnt++; 2329 q->bcnt += pktlen; 2330 f = q->rule; 2331 cmd = ACTION_PTR(f); 2332 l = f->cmd_len - f->act_ofs; 2333 IPFW_DYN_UNLOCK(); 2334 goto check_body; 2335 } 2336 /* 2337 * Dynamic entry not found. If CHECK_STATE, 2338 * skip to next rule, if PROBE_STATE just 2339 * ignore and continue with next opcode. 2340 */ 2341 if (cmd->opcode == O_CHECK_STATE) 2342 goto next_rule; 2343 match = 1; 2344 break; 2345 2346 case O_ACCEPT: 2347 retval = 0; /* accept */ 2348 goto done; 2349 2350 case O_PIPE: 2351 case O_QUEUE: 2352 args->rule = f; /* report matching rule */ 2353 retval = cmd->arg1 | IP_FW_PORT_DYNT_FLAG; 2354 goto done; 2355 2356 case O_DIVERT: 2357 case O_TEE: { 2358 struct divert_tag *dt; 2359 2360 if (args->eh) /* not on layer 2 */ 2361 break; 2362 mtag = m_tag_get(PACKET_TAG_DIVERT, 2363 sizeof(struct divert_tag), 2364 M_NOWAIT); 2365 if (mtag == NULL) { 2366 /* XXX statistic */ 2367 /* drop packet */ 2368 IPFW_UNLOCK(chain); 2369 return IP_FW_PORT_DENY_FLAG; 2370 } 2371 dt = (struct divert_tag *)(mtag+1); 2372 dt->cookie = f->rulenum; 2373 dt->info = (cmd->opcode == O_DIVERT) ? 2374 cmd->arg1 : 2375 cmd->arg1 | IP_FW_PORT_TEE_FLAG; 2376 m_tag_prepend(m, mtag); 2377 retval = dt->info; 2378 goto done; 2379 } 2380 2381 case O_COUNT: 2382 case O_SKIPTO: 2383 f->pcnt++; /* update stats */ 2384 f->bcnt += pktlen; 2385 f->timestamp = time_second; 2386 if (cmd->opcode == O_COUNT) 2387 goto next_rule; 2388 /* handle skipto */ 2389 if (f->next_rule == NULL) 2390 lookup_next_rule(f); 2391 f = f->next_rule; 2392 goto again; 2393 2394 case O_REJECT: 2395 /* 2396 * Drop the packet and send a reject notice 2397 * if the packet is not ICMP (or is an ICMP 2398 * query), and it is not multicast/broadcast. 2399 */ 2400 if (hlen > 0 && 2401 (proto != IPPROTO_ICMP || 2402 is_icmp_query(ip)) && 2403 !(m->m_flags & (M_BCAST|M_MCAST)) && 2404 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2405 send_reject(args, cmd->arg1, 2406 offset,ip_len); 2407 m = args->m; 2408 } 2409 /* FALLTHROUGH */ 2410 case O_DENY: 2411 retval = IP_FW_PORT_DENY_FLAG; 2412 goto done; 2413 2414 case O_FORWARD_IP: 2415 if (args->eh) /* not valid on layer2 pkts */ 2416 break; 2417 if (!q || dyn_dir == MATCH_FORWARD) 2418 args->next_hop = 2419 &((ipfw_insn_sa *)cmd)->sa; 2420 retval = 0; 2421 goto done; 2422 2423 default: 2424 panic("-- unknown opcode %d\n", cmd->opcode); 2425 } /* end of switch() on opcodes */ 2426 2427 if (cmd->len & F_NOT) 2428 match = !match; 2429 2430 if (match) { 2431 if (cmd->len & F_OR) 2432 skip_or = 1; 2433 } else { 2434 if (!(cmd->len & F_OR)) /* not an OR block, */ 2435 break; /* try next rule */ 2436 } 2437 2438 } /* end of inner for, scan opcodes */ 2439 2440next_rule:; /* try next rule */ 2441 2442 } /* end of outer for, scan rules */ 2443 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 2444 IPFW_UNLOCK(chain); 2445 return(IP_FW_PORT_DENY_FLAG); 2446 2447done: 2448 /* Update statistics */ 2449 f->pcnt++; 2450 f->bcnt += pktlen; 2451 f->timestamp = time_second; 2452 IPFW_UNLOCK(chain); 2453 return retval; 2454 2455pullup_failed: 2456 if (fw_verbose) 2457 printf("ipfw: pullup failed\n"); 2458 return(IP_FW_PORT_DENY_FLAG); 2459} 2460 2461/* 2462 * When a rule is added/deleted, clear the next_rule pointers in all rules. 2463 * These will be reconstructed on the fly as packets are matched. 2464 */ 2465static void 2466flush_rule_ptrs(struct ip_fw_chain *chain) 2467{ 2468 struct ip_fw *rule; 2469 2470 IPFW_LOCK_ASSERT(chain); 2471 2472 for (rule = chain->rules; rule; rule = rule->next) 2473 rule->next_rule = NULL; 2474} 2475 2476/* 2477 * When pipes/queues are deleted, clear the "pipe_ptr" pointer to a given 2478 * pipe/queue, or to all of them (match == NULL). 2479 */ 2480void 2481flush_pipe_ptrs(struct dn_flow_set *match) 2482{ 2483 struct ip_fw *rule; 2484 2485 IPFW_LOCK(&layer3_chain); 2486 for (rule = layer3_chain.rules; rule; rule = rule->next) { 2487 ipfw_insn_pipe *cmd = (ipfw_insn_pipe *)ACTION_PTR(rule); 2488 2489 if (cmd->o.opcode != O_PIPE && cmd->o.opcode != O_QUEUE) 2490 continue; 2491 /* 2492 * XXX Use bcmp/bzero to handle pipe_ptr to overcome 2493 * possible alignment problems on 64-bit architectures. 2494 * This code is seldom used so we do not worry too 2495 * much about efficiency. 2496 */ 2497 if (match == NULL || 2498 !bcmp(&cmd->pipe_ptr, &match, sizeof(match)) ) 2499 bzero(&cmd->pipe_ptr, sizeof(cmd->pipe_ptr)); 2500 } 2501 IPFW_UNLOCK(&layer3_chain); 2502} 2503 2504/* 2505 * Add a new rule to the list. Copy the rule into a malloc'ed area, then 2506 * possibly create a rule number and add the rule to the list. 2507 * Update the rule_number in the input struct so the caller knows it as well. 2508 */ 2509static int 2510add_rule(struct ip_fw_chain *chain, struct ip_fw *input_rule) 2511{ 2512 struct ip_fw *rule, *f, *prev; 2513 int l = RULESIZE(input_rule); 2514 2515 if (chain->rules == NULL && input_rule->rulenum != IPFW_DEFAULT_RULE) 2516 return (EINVAL); 2517 2518 rule = malloc(l, M_IPFW, M_NOWAIT | M_ZERO); 2519 if (rule == NULL) 2520 return (ENOSPC); 2521 2522 bcopy(input_rule, rule, l); 2523 2524 rule->next = NULL; 2525 rule->next_rule = NULL; 2526 2527 rule->pcnt = 0; 2528 rule->bcnt = 0; 2529 rule->timestamp = 0; 2530 2531 IPFW_LOCK(chain); 2532 2533 if (chain->rules == NULL) { /* default rule */ 2534 chain->rules = rule; 2535 goto done; 2536 } 2537 2538 /* 2539 * If rulenum is 0, find highest numbered rule before the 2540 * default rule, and add autoinc_step 2541 */ 2542 if (autoinc_step < 1) 2543 autoinc_step = 1; 2544 else if (autoinc_step > 1000) 2545 autoinc_step = 1000; 2546 if (rule->rulenum == 0) { 2547 /* 2548 * locate the highest numbered rule before default 2549 */ 2550 for (f = chain->rules; f; f = f->next) { 2551 if (f->rulenum == IPFW_DEFAULT_RULE) 2552 break; 2553 rule->rulenum = f->rulenum; 2554 } 2555 if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step) 2556 rule->rulenum += autoinc_step; 2557 input_rule->rulenum = rule->rulenum; 2558 } 2559 2560 /* 2561 * Now insert the new rule in the right place in the sorted list. 2562 */ 2563 for (prev = NULL, f = chain->rules; f; prev = f, f = f->next) { 2564 if (f->rulenum > rule->rulenum) { /* found the location */ 2565 if (prev) { 2566 rule->next = f; 2567 prev->next = rule; 2568 } else { /* head insert */ 2569 rule->next = chain->rules; 2570 chain->rules = rule; 2571 } 2572 break; 2573 } 2574 } 2575 flush_rule_ptrs(chain); 2576done: 2577 static_count++; 2578 static_len += l; 2579 IPFW_UNLOCK(chain); 2580 DEB(printf("ipfw: installed rule %d, static count now %d\n", 2581 rule->rulenum, static_count);) 2582 return (0); 2583} 2584 2585/** 2586 * Remove a static rule (including derived * dynamic rules) 2587 * and place it on the ``reap list'' for later reclamation. 2588 * The caller is in charge of clearing rule pointers to avoid 2589 * dangling pointers. 2590 * @return a pointer to the next entry. 2591 * Arguments are not checked, so they better be correct. 2592 */ 2593static struct ip_fw * 2594remove_rule(struct ip_fw_chain *chain, struct ip_fw *rule, struct ip_fw *prev) 2595{ 2596 struct ip_fw *n; 2597 int l = RULESIZE(rule); 2598 2599 IPFW_LOCK_ASSERT(chain); 2600 2601 n = rule->next; 2602 IPFW_DYN_LOCK(); 2603 remove_dyn_rule(rule, NULL /* force removal */); 2604 IPFW_DYN_UNLOCK(); 2605 if (prev == NULL) 2606 chain->rules = n; 2607 else 2608 prev->next = n; 2609 static_count--; 2610 static_len -= l; 2611 2612 rule->next = chain->reap; 2613 chain->reap = rule; 2614 2615 return n; 2616} 2617 2618/** 2619 * Reclaim storage associated with a list of rules. This is 2620 * typically the list created using remove_rule. 2621 */ 2622static void 2623reap_rules(struct ip_fw *head) 2624{ 2625 struct ip_fw *rule; 2626 2627 while ((rule = head) != NULL) { 2628 head = head->next; 2629 if (DUMMYNET_LOADED) 2630 ip_dn_ruledel_ptr(rule); 2631 free(rule, M_IPFW); 2632 } 2633} 2634 2635/* 2636 * Remove all rules from a chain (except rules in set RESVD_SET 2637 * unless kill_default = 1). The caller is responsible for 2638 * reclaiming storage for the rules left in chain->reap. 2639 */ 2640static void 2641free_chain(struct ip_fw_chain *chain, int kill_default) 2642{ 2643 struct ip_fw *prev, *rule; 2644 2645 IPFW_LOCK_ASSERT(chain); 2646 2647 flush_rule_ptrs(chain); /* more efficient to do outside the loop */ 2648 for (prev = NULL, rule = chain->rules; rule ; ) 2649 if (kill_default || rule->set != RESVD_SET) 2650 rule = remove_rule(chain, rule, prev); 2651 else { 2652 prev = rule; 2653 rule = rule->next; 2654 } 2655} 2656 2657/** 2658 * Remove all rules with given number, and also do set manipulation. 2659 * Assumes chain != NULL && *chain != NULL. 2660 * 2661 * The argument is an u_int32_t. The low 16 bit are the rule or set number, 2662 * the next 8 bits are the new set, the top 8 bits are the command: 2663 * 2664 * 0 delete rules with given number 2665 * 1 delete rules with given set number 2666 * 2 move rules with given number to new set 2667 * 3 move rules with given set number to new set 2668 * 4 swap sets with given numbers 2669 */ 2670static int 2671del_entry(struct ip_fw_chain *chain, u_int32_t arg) 2672{ 2673 struct ip_fw *prev = NULL, *rule; 2674 u_int16_t rulenum; /* rule or old_set */ 2675 u_int8_t cmd, new_set; 2676 2677 rulenum = arg & 0xffff; 2678 cmd = (arg >> 24) & 0xff; 2679 new_set = (arg >> 16) & 0xff; 2680 2681 if (cmd > 4) 2682 return EINVAL; 2683 if (new_set > RESVD_SET) 2684 return EINVAL; 2685 if (cmd == 0 || cmd == 2) { 2686 if (rulenum >= IPFW_DEFAULT_RULE) 2687 return EINVAL; 2688 } else { 2689 if (rulenum > RESVD_SET) /* old_set */ 2690 return EINVAL; 2691 } 2692 2693 IPFW_LOCK(chain); 2694 rule = chain->rules; 2695 chain->reap = NULL; 2696 switch (cmd) { 2697 case 0: /* delete rules with given number */ 2698 /* 2699 * locate first rule to delete 2700 */ 2701 for (; rule->rulenum < rulenum; prev = rule, rule = rule->next) 2702 ; 2703 if (rule->rulenum != rulenum) { 2704 IPFW_UNLOCK(chain); 2705 return EINVAL; 2706 } 2707 2708 /* 2709 * flush pointers outside the loop, then delete all matching 2710 * rules. prev remains the same throughout the cycle. 2711 */ 2712 flush_rule_ptrs(chain); 2713 while (rule->rulenum == rulenum) 2714 rule = remove_rule(chain, rule, prev); 2715 break; 2716 2717 case 1: /* delete all rules with given set number */ 2718 flush_rule_ptrs(chain); 2719 rule = chain->rules; 2720 while (rule->rulenum < IPFW_DEFAULT_RULE) 2721 if (rule->set == rulenum) 2722 rule = remove_rule(chain, rule, prev); 2723 else { 2724 prev = rule; 2725 rule = rule->next; 2726 } 2727 break; 2728 2729 case 2: /* move rules with given number to new set */ 2730 rule = chain->rules; 2731 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2732 if (rule->rulenum == rulenum) 2733 rule->set = new_set; 2734 break; 2735 2736 case 3: /* move rules with given set number to new set */ 2737 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2738 if (rule->set == rulenum) 2739 rule->set = new_set; 2740 break; 2741 2742 case 4: /* swap two sets */ 2743 for (; rule->rulenum < IPFW_DEFAULT_RULE; rule = rule->next) 2744 if (rule->set == rulenum) 2745 rule->set = new_set; 2746 else if (rule->set == new_set) 2747 rule->set = rulenum; 2748 break; 2749 } 2750 /* 2751 * Look for rules to reclaim. We grab the list before 2752 * releasing the lock then reclaim them w/o the lock to 2753 * avoid a LOR with dummynet. 2754 */ 2755 rule = chain->reap; 2756 chain->reap = NULL; 2757 IPFW_UNLOCK(chain); 2758 if (rule) 2759 reap_rules(rule); 2760 return 0; 2761} 2762 2763/* 2764 * Clear counters for a specific rule. 2765 * The enclosing "table" is assumed locked. 2766 */ 2767static void 2768clear_counters(struct ip_fw *rule, int log_only) 2769{ 2770 ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule); 2771 2772 if (log_only == 0) { 2773 rule->bcnt = rule->pcnt = 0; 2774 rule->timestamp = 0; 2775 } 2776 if (l->o.opcode == O_LOG) 2777 l->log_left = l->max_log; 2778} 2779 2780/** 2781 * Reset some or all counters on firewall rules. 2782 * @arg frwl is null to clear all entries, or contains a specific 2783 * rule number. 2784 * @arg log_only is 1 if we only want to reset logs, zero otherwise. 2785 */ 2786static int 2787zero_entry(struct ip_fw_chain *chain, int rulenum, int log_only) 2788{ 2789 struct ip_fw *rule; 2790 char *msg; 2791 2792 IPFW_LOCK(chain); 2793 if (rulenum == 0) { 2794 norule_counter = 0; 2795 for (rule = chain->rules; rule; rule = rule->next) 2796 clear_counters(rule, log_only); 2797 msg = log_only ? "ipfw: All logging counts reset.\n" : 2798 "ipfw: Accounting cleared.\n"; 2799 } else { 2800 int cleared = 0; 2801 /* 2802 * We can have multiple rules with the same number, so we 2803 * need to clear them all. 2804 */ 2805 for (rule = chain->rules; rule; rule = rule->next) 2806 if (rule->rulenum == rulenum) { 2807 while (rule && rule->rulenum == rulenum) { 2808 clear_counters(rule, log_only); 2809 rule = rule->next; 2810 } 2811 cleared = 1; 2812 break; 2813 } 2814 if (!cleared) { /* we did not find any matching rules */ 2815 IPFW_UNLOCK(chain); 2816 return (EINVAL); 2817 } 2818 msg = log_only ? "ipfw: Entry %d logging count reset.\n" : 2819 "ipfw: Entry %d cleared.\n"; 2820 } 2821 IPFW_UNLOCK(chain); 2822 2823 if (fw_verbose) 2824 log(LOG_SECURITY | LOG_NOTICE, msg, rulenum); 2825 return (0); 2826} 2827 2828/* 2829 * Check validity of the structure before insert. 2830 * Fortunately rules are simple, so this mostly need to check rule sizes. 2831 */ 2832static int 2833check_ipfw_struct(struct ip_fw *rule, int size) 2834{ 2835 int l, cmdlen = 0; 2836 int have_action=0; 2837 ipfw_insn *cmd; 2838 2839 if (size < sizeof(*rule)) { 2840 printf("ipfw: rule too short\n"); 2841 return (EINVAL); 2842 } 2843 /* first, check for valid size */ 2844 l = RULESIZE(rule); 2845 if (l != size) { 2846 printf("ipfw: size mismatch (have %d want %d)\n", size, l); 2847 return (EINVAL); 2848 } 2849 if (rule->act_ofs >= rule->cmd_len) { 2850 printf("ipfw: bogus action offset (%u > %u)\n", 2851 rule->act_ofs, rule->cmd_len - 1); 2852 return (EINVAL); 2853 } 2854 /* 2855 * Now go for the individual checks. Very simple ones, basically only 2856 * instruction sizes. 2857 */ 2858 for (l = rule->cmd_len, cmd = rule->cmd ; 2859 l > 0 ; l -= cmdlen, cmd += cmdlen) { 2860 cmdlen = F_LEN(cmd); 2861 if (cmdlen > l) { 2862 printf("ipfw: opcode %d size truncated\n", 2863 cmd->opcode); 2864 return EINVAL; 2865 } 2866 DEB(printf("ipfw: opcode %d\n", cmd->opcode);) 2867 switch (cmd->opcode) { 2868 case O_PROBE_STATE: 2869 case O_KEEP_STATE: 2870 case O_PROTO: 2871 case O_IP_SRC_ME: 2872 case O_IP_DST_ME: 2873 case O_LAYER2: 2874 case O_IN: 2875 case O_FRAG: 2876 case O_IPOPT: 2877 case O_IPTOS: 2878 case O_IPPRECEDENCE: 2879 case O_IPVER: 2880 case O_TCPWIN: 2881 case O_TCPFLAGS: 2882 case O_TCPOPTS: 2883 case O_ESTAB: 2884 case O_VERREVPATH: 2885 case O_VERSRCREACH: 2886 case O_ANTISPOOF: 2887 case O_IPSEC: 2888 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 2889 goto bad_size; 2890 break; 2891 2892 case O_UID: 2893 case O_GID: 2894 case O_JAIL: 2895 case O_IP_SRC: 2896 case O_IP_DST: 2897 case O_TCPSEQ: 2898 case O_TCPACK: 2899 case O_PROB: 2900 case O_ICMPTYPE: 2901 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 2902 goto bad_size; 2903 break; 2904 2905 case O_LIMIT: 2906 if (cmdlen != F_INSN_SIZE(ipfw_insn_limit)) 2907 goto bad_size; 2908 break; 2909 2910 case O_LOG: 2911 if (cmdlen != F_INSN_SIZE(ipfw_insn_log)) 2912 goto bad_size; 2913 2914 ((ipfw_insn_log *)cmd)->log_left = 2915 ((ipfw_insn_log *)cmd)->max_log; 2916 2917 break; 2918 2919 case O_IP_SRC_MASK: 2920 case O_IP_DST_MASK: 2921 /* only odd command lengths */ 2922 if ( !(cmdlen & 1) || cmdlen > 31) 2923 goto bad_size; 2924 break; 2925 2926 case O_IP_SRC_SET: 2927 case O_IP_DST_SET: 2928 if (cmd->arg1 == 0 || cmd->arg1 > 256) { 2929 printf("ipfw: invalid set size %d\n", 2930 cmd->arg1); 2931 return EINVAL; 2932 } 2933 if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) + 2934 (cmd->arg1+31)/32 ) 2935 goto bad_size; 2936 break; 2937 2938 case O_IP_SRC_LOOKUP: 2939 case O_IP_DST_LOOKUP: 2940 if (cmd->arg1 >= IPFW_TABLES_MAX) { 2941 printf("ipfw: invalid table number %d\n", 2942 cmd->arg1); 2943 return (EINVAL); 2944 } 2945 if (cmdlen != F_INSN_SIZE(ipfw_insn) && 2946 cmdlen != F_INSN_SIZE(ipfw_insn_u32)) 2947 goto bad_size; 2948 break; 2949 2950 case O_MACADDR2: 2951 if (cmdlen != F_INSN_SIZE(ipfw_insn_mac)) 2952 goto bad_size; 2953 break; 2954 2955 case O_NOP: 2956 case O_IPID: 2957 case O_IPTTL: 2958 case O_IPLEN: 2959 if (cmdlen < 1 || cmdlen > 31) 2960 goto bad_size; 2961 break; 2962 2963 case O_MAC_TYPE: 2964 case O_IP_SRCPORT: 2965 case O_IP_DSTPORT: /* XXX artificial limit, 30 port pairs */ 2966 if (cmdlen < 2 || cmdlen > 31) 2967 goto bad_size; 2968 break; 2969 2970 case O_RECV: 2971 case O_XMIT: 2972 case O_VIA: 2973 if (cmdlen != F_INSN_SIZE(ipfw_insn_if)) 2974 goto bad_size; 2975 break; 2976 2977 case O_PIPE: 2978 case O_QUEUE: 2979 if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe)) 2980 goto bad_size; 2981 goto check_action; 2982 2983 case O_FORWARD_IP: 2984#ifdef IPFIREWALL_FORWARD 2985 if (cmdlen != F_INSN_SIZE(ipfw_insn_sa)) 2986 goto bad_size; 2987 goto check_action; 2988#else 2989 return EINVAL; 2990#endif 2991 2992 case O_DIVERT: 2993 case O_TEE: 2994#ifndef IPDIVERT 2995 return EINVAL; 2996#endif 2997 case O_FORWARD_MAC: /* XXX not implemented yet */ 2998 case O_CHECK_STATE: 2999 case O_COUNT: 3000 case O_ACCEPT: 3001 case O_DENY: 3002 case O_REJECT: 3003 case O_SKIPTO: 3004 if (cmdlen != F_INSN_SIZE(ipfw_insn)) 3005 goto bad_size; 3006check_action: 3007 if (have_action) { 3008 printf("ipfw: opcode %d, multiple actions" 3009 " not allowed\n", 3010 cmd->opcode); 3011 return EINVAL; 3012 } 3013 have_action = 1; 3014 if (l != cmdlen) { 3015 printf("ipfw: opcode %d, action must be" 3016 " last opcode\n", 3017 cmd->opcode); 3018 return EINVAL; 3019 } 3020 break; 3021 default: 3022 printf("ipfw: opcode %d, unknown opcode\n", 3023 cmd->opcode); 3024 return EINVAL; 3025 } 3026 } 3027 if (have_action == 0) { 3028 printf("ipfw: missing action\n"); 3029 return EINVAL; 3030 } 3031 return 0; 3032 3033bad_size: 3034 printf("ipfw: opcode %d size %d wrong\n", 3035 cmd->opcode, cmdlen); 3036 return EINVAL; 3037} 3038 3039/* 3040 * Copy the static and dynamic rules to the supplied buffer 3041 * and return the amount of space actually used. 3042 */ 3043static size_t 3044ipfw_getrules(struct ip_fw_chain *chain, void *buf, size_t space) 3045{ 3046 char *bp = buf; 3047 char *ep = bp + space; 3048 struct ip_fw *rule; 3049 int i; 3050 3051 /* XXX this can take a long time and locking will block packet flow */ 3052 IPFW_LOCK(chain); 3053 for (rule = chain->rules; rule ; rule = rule->next) { 3054 /* 3055 * Verify the entry fits in the buffer in case the 3056 * rules changed between calculating buffer space and 3057 * now. This would be better done using a generation 3058 * number but should suffice for now. 3059 */ 3060 i = RULESIZE(rule); 3061 if (bp + i <= ep) { 3062 bcopy(rule, bp, i); 3063 bcopy(&set_disable, &(((struct ip_fw *)bp)->next_rule), 3064 sizeof(set_disable)); 3065 bp += i; 3066 } 3067 } 3068 IPFW_UNLOCK(chain); 3069 if (ipfw_dyn_v) { 3070 ipfw_dyn_rule *p, *last = NULL; 3071 3072 IPFW_DYN_LOCK(); 3073 for (i = 0 ; i < curr_dyn_buckets; i++) 3074 for (p = ipfw_dyn_v[i] ; p != NULL; p = p->next) { 3075 if (bp + sizeof *p <= ep) { 3076 ipfw_dyn_rule *dst = 3077 (ipfw_dyn_rule *)bp; 3078 bcopy(p, dst, sizeof *p); 3079 bcopy(&(p->rule->rulenum), &(dst->rule), 3080 sizeof(p->rule->rulenum)); 3081 /* 3082 * store a non-null value in "next". 3083 * The userland code will interpret a 3084 * NULL here as a marker 3085 * for the last dynamic rule. 3086 */ 3087 bcopy(&dst, &dst->next, sizeof(dst)); 3088 last = dst; 3089 dst->expire = 3090 TIME_LEQ(dst->expire, time_second) ? 3091 0 : dst->expire - time_second ; 3092 bp += sizeof(ipfw_dyn_rule); 3093 } 3094 } 3095 IPFW_DYN_UNLOCK(); 3096 if (last != NULL) /* mark last dynamic rule */ 3097 bzero(&last->next, sizeof(last)); 3098 } 3099 return (bp - (char *)buf); 3100} 3101 3102 3103/** 3104 * {set|get}sockopt parser. 3105 */ 3106static int 3107ipfw_ctl(struct sockopt *sopt) 3108{ 3109#define RULE_MAXSIZE (256*sizeof(u_int32_t)) 3110 int error, rule_num; 3111 size_t size; 3112 struct ip_fw *buf, *rule; 3113 u_int32_t rulenum[2]; 3114 3115 error = suser(sopt->sopt_td); 3116 if (error) 3117 return (error); 3118 3119 /* 3120 * Disallow modifications in really-really secure mode, but still allow 3121 * the logging counters to be reset. 3122 */ 3123 if (sopt->sopt_name == IP_FW_ADD || 3124 (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) { 3125#if __FreeBSD_version >= 500034 3126 error = securelevel_ge(sopt->sopt_td->td_ucred, 3); 3127 if (error) 3128 return (error); 3129#else /* FreeBSD 4.x */ 3130 if (securelevel >= 3) 3131 return (EPERM); 3132#endif 3133 } 3134 3135 error = 0; 3136 3137 switch (sopt->sopt_name) { 3138 case IP_FW_GET: 3139 /* 3140 * pass up a copy of the current rules. Static rules 3141 * come first (the last of which has number IPFW_DEFAULT_RULE), 3142 * followed by a possibly empty list of dynamic rule. 3143 * The last dynamic rule has NULL in the "next" field. 3144 * 3145 * Note that the calculated size is used to bound the 3146 * amount of data returned to the user. The rule set may 3147 * change between calculating the size and returning the 3148 * data in which case we'll just return what fits. 3149 */ 3150 size = static_len; /* size of static rules */ 3151 if (ipfw_dyn_v) /* add size of dyn.rules */ 3152 size += (dyn_count * sizeof(ipfw_dyn_rule)); 3153 3154 /* 3155 * XXX todo: if the user passes a short length just to know 3156 * how much room is needed, do not bother filling up the 3157 * buffer, just jump to the sooptcopyout. 3158 */ 3159 buf = malloc(size, M_TEMP, M_WAITOK); 3160 error = sooptcopyout(sopt, buf, 3161 ipfw_getrules(&layer3_chain, buf, size)); 3162 free(buf, M_TEMP); 3163 break; 3164 3165 case IP_FW_FLUSH: 3166 /* 3167 * Normally we cannot release the lock on each iteration. 3168 * We could do it here only because we start from the head all 3169 * the times so there is no risk of missing some entries. 3170 * On the other hand, the risk is that we end up with 3171 * a very inconsistent ruleset, so better keep the lock 3172 * around the whole cycle. 3173 * 3174 * XXX this code can be improved by resetting the head of 3175 * the list to point to the default rule, and then freeing 3176 * the old list without the need for a lock. 3177 */ 3178 3179 IPFW_LOCK(&layer3_chain); 3180 layer3_chain.reap = NULL; 3181 free_chain(&layer3_chain, 0 /* keep default rule */); 3182 rule = layer3_chain.reap, layer3_chain.reap = NULL; 3183 IPFW_UNLOCK(&layer3_chain); 3184 if (layer3_chain.reap != NULL) 3185 reap_rules(rule); 3186 break; 3187 3188 case IP_FW_ADD: 3189 rule = malloc(RULE_MAXSIZE, M_TEMP, M_WAITOK); 3190 error = sooptcopyin(sopt, rule, RULE_MAXSIZE, 3191 sizeof(struct ip_fw) ); 3192 if (error == 0) 3193 error = check_ipfw_struct(rule, sopt->sopt_valsize); 3194 if (error == 0) { 3195 error = add_rule(&layer3_chain, rule); 3196 size = RULESIZE(rule); 3197 if (!error && sopt->sopt_dir == SOPT_GET) 3198 error = sooptcopyout(sopt, rule, size); 3199 } 3200 free(rule, M_TEMP); 3201 break; 3202 3203 case IP_FW_DEL: 3204 /* 3205 * IP_FW_DEL is used for deleting single rules or sets, 3206 * and (ab)used to atomically manipulate sets. Argument size 3207 * is used to distinguish between the two: 3208 * sizeof(u_int32_t) 3209 * delete single rule or set of rules, 3210 * or reassign rules (or sets) to a different set. 3211 * 2*sizeof(u_int32_t) 3212 * atomic disable/enable sets. 3213 * first u_int32_t contains sets to be disabled, 3214 * second u_int32_t contains sets to be enabled. 3215 */ 3216 error = sooptcopyin(sopt, rulenum, 3217 2*sizeof(u_int32_t), sizeof(u_int32_t)); 3218 if (error) 3219 break; 3220 size = sopt->sopt_valsize; 3221 if (size == sizeof(u_int32_t)) /* delete or reassign */ 3222 error = del_entry(&layer3_chain, rulenum[0]); 3223 else if (size == 2*sizeof(u_int32_t)) /* set enable/disable */ 3224 set_disable = 3225 (set_disable | rulenum[0]) & ~rulenum[1] & 3226 ~(1<<RESVD_SET); /* set RESVD_SET always enabled */ 3227 else 3228 error = EINVAL; 3229 break; 3230 3231 case IP_FW_ZERO: 3232 case IP_FW_RESETLOG: /* argument is an int, the rule number */ 3233 rule_num = 0; 3234 if (sopt->sopt_val != 0) { 3235 error = sooptcopyin(sopt, &rule_num, 3236 sizeof(int), sizeof(int)); 3237 if (error) 3238 break; 3239 } 3240 error = zero_entry(&layer3_chain, rule_num, 3241 sopt->sopt_name == IP_FW_RESETLOG); 3242 break; 3243 3244 case IP_FW_TABLE_ADD: 3245 { 3246 ipfw_table_entry ent; 3247 3248 error = sooptcopyin(sopt, &ent, 3249 sizeof(ent), sizeof(ent)); 3250 if (error) 3251 break; 3252 error = add_table_entry(ent.tbl, ent.addr, 3253 ent.masklen, ent.value); 3254 } 3255 break; 3256 3257 case IP_FW_TABLE_DEL: 3258 { 3259 ipfw_table_entry ent; 3260 3261 error = sooptcopyin(sopt, &ent, 3262 sizeof(ent), sizeof(ent)); 3263 if (error) 3264 break; 3265 error = del_table_entry(ent.tbl, ent.addr, ent.masklen); 3266 } 3267 break; 3268 3269 case IP_FW_TABLE_FLUSH: 3270 { 3271 u_int16_t tbl; 3272 3273 error = sooptcopyin(sopt, &tbl, 3274 sizeof(tbl), sizeof(tbl)); 3275 if (error) 3276 break; 3277 error = flush_table(tbl); 3278 } 3279 break; 3280 3281 case IP_FW_TABLE_GETSIZE: 3282 { 3283 u_int32_t tbl, cnt; 3284 3285 if ((error = sooptcopyin(sopt, &tbl, sizeof(tbl), 3286 sizeof(tbl)))) 3287 break; 3288 if ((error = count_table(tbl, &cnt))) 3289 break; 3290 error = sooptcopyout(sopt, &cnt, sizeof(cnt)); 3291 } 3292 break; 3293 3294 case IP_FW_TABLE_LIST: 3295 { 3296 ipfw_table *tbl; 3297 3298 if (sopt->sopt_valsize < sizeof(*tbl)) { 3299 error = EINVAL; 3300 break; 3301 } 3302 size = sopt->sopt_valsize; 3303 tbl = malloc(size, M_TEMP, M_WAITOK); 3304 if (tbl == NULL) { 3305 error = ENOMEM; 3306 break; 3307 } 3308 error = sooptcopyin(sopt, tbl, size, sizeof(*tbl)); 3309 if (error) { 3310 free(tbl, M_TEMP); 3311 break; 3312 } 3313 tbl->size = (size - sizeof(*tbl)) / 3314 sizeof(ipfw_table_entry); 3315 error = dump_table(tbl); 3316 if (error) { 3317 free(tbl, M_TEMP); 3318 break; 3319 } 3320 error = sooptcopyout(sopt, tbl, size); 3321 free(tbl, M_TEMP); 3322 } 3323 break; 3324 3325 default: 3326 printf("ipfw: ipfw_ctl invalid option %d\n", sopt->sopt_name); 3327 error = EINVAL; 3328 } 3329 3330 return (error); 3331#undef RULE_MAXSIZE 3332} 3333 3334/** 3335 * dummynet needs a reference to the default rule, because rules can be 3336 * deleted while packets hold a reference to them. When this happens, 3337 * dummynet changes the reference to the default rule (it could well be a 3338 * NULL pointer, but this way we do not need to check for the special 3339 * case, plus here he have info on the default behaviour). 3340 */ 3341struct ip_fw *ip_fw_default_rule; 3342 3343/* 3344 * This procedure is only used to handle keepalives. It is invoked 3345 * every dyn_keepalive_period 3346 */ 3347static void 3348ipfw_tick(void * __unused unused) 3349{ 3350 int i; 3351 ipfw_dyn_rule *q; 3352 3353 if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0) 3354 goto done; 3355 3356 IPFW_DYN_LOCK(); 3357 for (i = 0 ; i < curr_dyn_buckets ; i++) { 3358 for (q = ipfw_dyn_v[i] ; q ; q = q->next ) { 3359 if (q->dyn_type == O_LIMIT_PARENT) 3360 continue; 3361 if (q->id.proto != IPPROTO_TCP) 3362 continue; 3363 if ( (q->state & BOTH_SYN) != BOTH_SYN) 3364 continue; 3365 if (TIME_LEQ( time_second+dyn_keepalive_interval, 3366 q->expire)) 3367 continue; /* too early */ 3368 if (TIME_LEQ(q->expire, time_second)) 3369 continue; /* too late, rule expired */ 3370 3371 send_pkt(&(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 3372 send_pkt(&(q->id), q->ack_fwd - 1, q->ack_rev, 0); 3373 } 3374 } 3375 IPFW_DYN_UNLOCK(); 3376done: 3377 callout_reset(&ipfw_timeout, dyn_keepalive_period*hz, ipfw_tick, NULL); 3378} 3379 3380int 3381ipfw_init(void) 3382{ 3383 struct ip_fw default_rule; 3384 int error; 3385 3386 layer3_chain.rules = NULL; 3387 IPFW_LOCK_INIT(&layer3_chain); 3388 IPFW_DYN_LOCK_INIT(); 3389 callout_init(&ipfw_timeout, debug_mpsafenet ? CALLOUT_MPSAFE : 0); 3390 3391 bzero(&default_rule, sizeof default_rule); 3392 3393 default_rule.act_ofs = 0; 3394 default_rule.rulenum = IPFW_DEFAULT_RULE; 3395 default_rule.cmd_len = 1; 3396 default_rule.set = RESVD_SET; 3397 3398 default_rule.cmd[0].len = 1; 3399 default_rule.cmd[0].opcode = 3400#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 3401 1 ? O_ACCEPT : 3402#endif 3403 O_DENY; 3404 3405 error = add_rule(&layer3_chain, &default_rule); 3406 if (error != 0) { 3407 printf("ipfw2: error %u initializing default rule " 3408 "(support disabled)\n", error); 3409 IPFW_DYN_LOCK_DESTROY(); 3410 IPFW_LOCK_DESTROY(&layer3_chain); 3411 return (error); 3412 } 3413 3414 ip_fw_default_rule = layer3_chain.rules; 3415 printf("ipfw2 initialized, divert %s, " 3416 "rule-based forwarding " 3417#ifdef IPFIREWALL_FORWARD 3418 "enabled, " 3419#else 3420 "disabled, " 3421#endif 3422 "default to %s, logging ", 3423#ifdef IPDIVERT 3424 "enabled", 3425#else 3426 "disabled", 3427#endif 3428 default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny"); 3429 3430#ifdef IPFIREWALL_VERBOSE 3431 fw_verbose = 1; 3432#endif 3433#ifdef IPFIREWALL_VERBOSE_LIMIT 3434 verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 3435#endif 3436 if (fw_verbose == 0) 3437 printf("disabled\n"); 3438 else if (verbose_limit == 0) 3439 printf("unlimited\n"); 3440 else 3441 printf("limited to %d packets/entry by default\n", 3442 verbose_limit); 3443 3444 init_tables(); 3445 ip_fw_ctl_ptr = ipfw_ctl; 3446 ip_fw_chk_ptr = ipfw_chk; 3447 callout_reset(&ipfw_timeout, hz, ipfw_tick, NULL); 3448 3449 return (0); 3450} 3451 3452void 3453ipfw_destroy(void) 3454{ 3455 struct ip_fw *reap; 3456 3457 ip_fw_chk_ptr = NULL; 3458 ip_fw_ctl_ptr = NULL; 3459 callout_drain(&ipfw_timeout); 3460 IPFW_LOCK(&layer3_chain); 3461 layer3_chain.reap = NULL; 3462 free_chain(&layer3_chain, 1 /* kill default rule */); 3463 reap = layer3_chain.reap, layer3_chain.reap = NULL; 3464 IPFW_UNLOCK(&layer3_chain); 3465 if (reap != NULL) 3466 reap_rules(reap); 3467 flush_tables(); 3468 IPFW_DYN_LOCK_DESTROY(); 3469 IPFW_LOCK_DESTROY(&layer3_chain); 3470 printf("IP firewall unloaded\n"); 3471} 3472 3473#endif /* IPFW2 */ 3474