ip_fw2.c revision 223080
1/*- 2 * Copyright (c) 2002-2009 Luigi Rizzo, Universita` di Pisa 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26#include <sys/cdefs.h> 27__FBSDID("$FreeBSD: head/sys/netinet/ipfw/ip_fw2.c 223080 2011-06-14 13:35:24Z ae $"); 28 29/* 30 * The FreeBSD IP packet firewall, main file 31 */ 32 33#if !defined(KLD_MODULE) 34#include "opt_ipfw.h" 35#include "opt_ipdivert.h" 36#include "opt_ipdn.h" 37#include "opt_inet.h" 38#ifndef INET 39#error IPFIREWALL requires INET. 40#endif /* INET */ 41#endif 42#include "opt_inet6.h" 43#include "opt_ipsec.h" 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/condvar.h> 48#include <sys/eventhandler.h> 49#include <sys/malloc.h> 50#include <sys/mbuf.h> 51#include <sys/kernel.h> 52#include <sys/lock.h> 53#include <sys/jail.h> 54#include <sys/module.h> 55#include <sys/priv.h> 56#include <sys/proc.h> 57#include <sys/rwlock.h> 58#include <sys/socket.h> 59#include <sys/socketvar.h> 60#include <sys/sysctl.h> 61#include <sys/syslog.h> 62#include <sys/ucred.h> 63#include <net/ethernet.h> /* for ETHERTYPE_IP */ 64#include <net/if.h> 65#include <net/route.h> 66#include <net/pf_mtag.h> 67#include <net/vnet.h> 68 69#include <netinet/in.h> 70#include <netinet/in_var.h> 71#include <netinet/in_pcb.h> 72#include <netinet/ip.h> 73#include <netinet/ip_var.h> 74#include <netinet/ip_icmp.h> 75#include <netinet/ip_fw.h> 76#include <netinet/ipfw/ip_fw_private.h> 77#include <netinet/ip_carp.h> 78#include <netinet/pim.h> 79#include <netinet/tcp_var.h> 80#include <netinet/udp.h> 81#include <netinet/udp_var.h> 82#include <netinet/sctp.h> 83 84#include <netinet/ip6.h> 85#include <netinet/icmp6.h> 86#ifdef INET6 87#include <netinet6/in6_pcb.h> 88#include <netinet6/scope6_var.h> 89#include <netinet6/ip6_var.h> 90#endif 91 92#include <machine/in_cksum.h> /* XXX for in_cksum */ 93 94#ifdef MAC 95#include <security/mac/mac_framework.h> 96#endif 97 98/* 99 * static variables followed by global ones. 100 * All ipfw global variables are here. 101 */ 102 103/* ipfw_vnet_ready controls when we are open for business */ 104static VNET_DEFINE(int, ipfw_vnet_ready) = 0; 105#define V_ipfw_vnet_ready VNET(ipfw_vnet_ready) 106 107static VNET_DEFINE(int, fw_deny_unknown_exthdrs); 108#define V_fw_deny_unknown_exthdrs VNET(fw_deny_unknown_exthdrs) 109 110#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT 111static int default_to_accept = 1; 112#else 113static int default_to_accept; 114#endif 115 116VNET_DEFINE(int, autoinc_step); 117VNET_DEFINE(int, fw_one_pass) = 1; 118 119/* 120 * Each rule belongs to one of 32 different sets (0..31). 121 * The variable set_disable contains one bit per set. 122 * If the bit is set, all rules in the corresponding set 123 * are disabled. Set RESVD_SET(31) is reserved for the default rule 124 * and rules that are not deleted by the flush command, 125 * and CANNOT be disabled. 126 * Rules in set RESVD_SET can only be deleted individually. 127 */ 128VNET_DEFINE(u_int32_t, set_disable); 129#define V_set_disable VNET(set_disable) 130 131VNET_DEFINE(int, fw_verbose); 132/* counter for ipfw_log(NULL...) */ 133VNET_DEFINE(u_int64_t, norule_counter); 134VNET_DEFINE(int, verbose_limit); 135 136/* layer3_chain contains the list of rules for layer 3 */ 137VNET_DEFINE(struct ip_fw_chain, layer3_chain); 138 139ipfw_nat_t *ipfw_nat_ptr = NULL; 140struct cfg_nat *(*lookup_nat_ptr)(struct nat_list *, int); 141ipfw_nat_cfg_t *ipfw_nat_cfg_ptr; 142ipfw_nat_cfg_t *ipfw_nat_del_ptr; 143ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr; 144ipfw_nat_cfg_t *ipfw_nat_get_log_ptr; 145 146#ifdef SYSCTL_NODE 147uint32_t dummy_def = IPFW_DEFAULT_RULE; 148uint32_t dummy_tables_max = IPFW_TABLES_MAX; 149 150SYSBEGIN(f3) 151 152SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 153SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, one_pass, 154 CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_one_pass), 0, 155 "Only do a single pass through ipfw when using dummynet(4)"); 156SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, 157 CTLFLAG_RW, &VNET_NAME(autoinc_step), 0, 158 "Rule number auto-increment step"); 159SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, verbose, 160 CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_verbose), 0, 161 "Log matches to ipfw rules"); 162SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, 163 CTLFLAG_RW, &VNET_NAME(verbose_limit), 0, 164 "Set upper limit of matches of ipfw rules logged"); 165SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, default_rule, CTLFLAG_RD, 166 &dummy_def, 0, 167 "The default/max possible rule number."); 168SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, tables_max, CTLFLAG_RD, 169 &dummy_tables_max, 0, 170 "The maximum number of tables."); 171SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, default_to_accept, CTLFLAG_RDTUN, 172 &default_to_accept, 0, 173 "Make the default rule accept all packets."); 174TUNABLE_INT("net.inet.ip.fw.default_to_accept", &default_to_accept); 175SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, static_count, 176 CTLFLAG_RD, &VNET_NAME(layer3_chain.n_rules), 0, 177 "Number of static rules"); 178 179#ifdef INET6 180SYSCTL_DECL(_net_inet6_ip6); 181SYSCTL_NODE(_net_inet6_ip6, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall"); 182SYSCTL_VNET_INT(_net_inet6_ip6_fw, OID_AUTO, deny_unknown_exthdrs, 183 CTLFLAG_RW | CTLFLAG_SECURE, &VNET_NAME(fw_deny_unknown_exthdrs), 0, 184 "Deny packets with unknown IPv6 Extension Headers"); 185#endif /* INET6 */ 186 187SYSEND 188 189#endif /* SYSCTL_NODE */ 190 191 192/* 193 * Some macros used in the various matching options. 194 * L3HDR maps an ipv4 pointer into a layer3 header pointer of type T 195 * Other macros just cast void * into the appropriate type 196 */ 197#define L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl)) 198#define TCP(p) ((struct tcphdr *)(p)) 199#define SCTP(p) ((struct sctphdr *)(p)) 200#define UDP(p) ((struct udphdr *)(p)) 201#define ICMP(p) ((struct icmphdr *)(p)) 202#define ICMP6(p) ((struct icmp6_hdr *)(p)) 203 204static __inline int 205icmptype_match(struct icmphdr *icmp, ipfw_insn_u32 *cmd) 206{ 207 int type = icmp->icmp_type; 208 209 return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) ); 210} 211 212#define TT ( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \ 213 (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) ) 214 215static int 216is_icmp_query(struct icmphdr *icmp) 217{ 218 int type = icmp->icmp_type; 219 220 return (type <= ICMP_MAXTYPE && (TT & (1<<type)) ); 221} 222#undef TT 223 224/* 225 * The following checks use two arrays of 8 or 16 bits to store the 226 * bits that we want set or clear, respectively. They are in the 227 * low and high half of cmd->arg1 or cmd->d[0]. 228 * 229 * We scan options and store the bits we find set. We succeed if 230 * 231 * (want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear 232 * 233 * The code is sometimes optimized not to store additional variables. 234 */ 235 236static int 237flags_match(ipfw_insn *cmd, u_int8_t bits) 238{ 239 u_char want_clear; 240 bits = ~bits; 241 242 if ( ((cmd->arg1 & 0xff) & bits) != 0) 243 return 0; /* some bits we want set were clear */ 244 want_clear = (cmd->arg1 >> 8) & 0xff; 245 if ( (want_clear & bits) != want_clear) 246 return 0; /* some bits we want clear were set */ 247 return 1; 248} 249 250static int 251ipopts_match(struct ip *ip, ipfw_insn *cmd) 252{ 253 int optlen, bits = 0; 254 u_char *cp = (u_char *)(ip + 1); 255 int x = (ip->ip_hl << 2) - sizeof (struct ip); 256 257 for (; x > 0; x -= optlen, cp += optlen) { 258 int opt = cp[IPOPT_OPTVAL]; 259 260 if (opt == IPOPT_EOL) 261 break; 262 if (opt == IPOPT_NOP) 263 optlen = 1; 264 else { 265 optlen = cp[IPOPT_OLEN]; 266 if (optlen <= 0 || optlen > x) 267 return 0; /* invalid or truncated */ 268 } 269 switch (opt) { 270 271 default: 272 break; 273 274 case IPOPT_LSRR: 275 bits |= IP_FW_IPOPT_LSRR; 276 break; 277 278 case IPOPT_SSRR: 279 bits |= IP_FW_IPOPT_SSRR; 280 break; 281 282 case IPOPT_RR: 283 bits |= IP_FW_IPOPT_RR; 284 break; 285 286 case IPOPT_TS: 287 bits |= IP_FW_IPOPT_TS; 288 break; 289 } 290 } 291 return (flags_match(cmd, bits)); 292} 293 294static int 295tcpopts_match(struct tcphdr *tcp, ipfw_insn *cmd) 296{ 297 int optlen, bits = 0; 298 u_char *cp = (u_char *)(tcp + 1); 299 int x = (tcp->th_off << 2) - sizeof(struct tcphdr); 300 301 for (; x > 0; x -= optlen, cp += optlen) { 302 int opt = cp[0]; 303 if (opt == TCPOPT_EOL) 304 break; 305 if (opt == TCPOPT_NOP) 306 optlen = 1; 307 else { 308 optlen = cp[1]; 309 if (optlen <= 0) 310 break; 311 } 312 313 switch (opt) { 314 315 default: 316 break; 317 318 case TCPOPT_MAXSEG: 319 bits |= IP_FW_TCPOPT_MSS; 320 break; 321 322 case TCPOPT_WINDOW: 323 bits |= IP_FW_TCPOPT_WINDOW; 324 break; 325 326 case TCPOPT_SACK_PERMITTED: 327 case TCPOPT_SACK: 328 bits |= IP_FW_TCPOPT_SACK; 329 break; 330 331 case TCPOPT_TIMESTAMP: 332 bits |= IP_FW_TCPOPT_TS; 333 break; 334 335 } 336 } 337 return (flags_match(cmd, bits)); 338} 339 340static int 341iface_match(struct ifnet *ifp, ipfw_insn_if *cmd) 342{ 343 if (ifp == NULL) /* no iface with this packet, match fails */ 344 return 0; 345 /* Check by name or by IP address */ 346 if (cmd->name[0] != '\0') { /* match by name */ 347 /* Check name */ 348 if (cmd->p.glob) { 349 if (fnmatch(cmd->name, ifp->if_xname, 0) == 0) 350 return(1); 351 } else { 352 if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0) 353 return(1); 354 } 355 } else { 356#ifdef __FreeBSD__ /* and OSX too ? */ 357 struct ifaddr *ia; 358 359 if_addr_rlock(ifp); 360 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) { 361 if (ia->ifa_addr->sa_family != AF_INET) 362 continue; 363 if (cmd->p.ip.s_addr == ((struct sockaddr_in *) 364 (ia->ifa_addr))->sin_addr.s_addr) { 365 if_addr_runlock(ifp); 366 return(1); /* match */ 367 } 368 } 369 if_addr_runlock(ifp); 370#endif /* __FreeBSD__ */ 371 } 372 return(0); /* no match, fail ... */ 373} 374 375/* 376 * The verify_path function checks if a route to the src exists and 377 * if it is reachable via ifp (when provided). 378 * 379 * The 'verrevpath' option checks that the interface that an IP packet 380 * arrives on is the same interface that traffic destined for the 381 * packet's source address would be routed out of. 382 * The 'versrcreach' option just checks that the source address is 383 * reachable via any route (except default) in the routing table. 384 * These two are a measure to block forged packets. This is also 385 * commonly known as "anti-spoofing" or Unicast Reverse Path 386 * Forwarding (Unicast RFP) in Cisco-ese. The name of the knobs 387 * is purposely reminiscent of the Cisco IOS command, 388 * 389 * ip verify unicast reverse-path 390 * ip verify unicast source reachable-via any 391 * 392 * which implements the same functionality. But note that the syntax 393 * is misleading, and the check may be performed on all IP packets 394 * whether unicast, multicast, or broadcast. 395 */ 396static int 397verify_path(struct in_addr src, struct ifnet *ifp, u_int fib) 398{ 399#ifndef __FreeBSD__ 400 return 0; 401#else 402 struct route ro; 403 struct sockaddr_in *dst; 404 405 bzero(&ro, sizeof(ro)); 406 407 dst = (struct sockaddr_in *)&(ro.ro_dst); 408 dst->sin_family = AF_INET; 409 dst->sin_len = sizeof(*dst); 410 dst->sin_addr = src; 411 in_rtalloc_ign(&ro, 0, fib); 412 413 if (ro.ro_rt == NULL) 414 return 0; 415 416 /* 417 * If ifp is provided, check for equality with rtentry. 418 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 419 * in order to pass packets injected back by if_simloop(): 420 * if useloopback == 1 routing entry (via lo0) for our own address 421 * may exist, so we need to handle routing assymetry. 422 */ 423 if (ifp != NULL && ro.ro_rt->rt_ifa->ifa_ifp != ifp) { 424 RTFREE(ro.ro_rt); 425 return 0; 426 } 427 428 /* if no ifp provided, check if rtentry is not default route */ 429 if (ifp == NULL && 430 satosin(rt_key(ro.ro_rt))->sin_addr.s_addr == INADDR_ANY) { 431 RTFREE(ro.ro_rt); 432 return 0; 433 } 434 435 /* or if this is a blackhole/reject route */ 436 if (ifp == NULL && ro.ro_rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 437 RTFREE(ro.ro_rt); 438 return 0; 439 } 440 441 /* found valid route */ 442 RTFREE(ro.ro_rt); 443 return 1; 444#endif /* __FreeBSD__ */ 445} 446 447#ifdef INET6 448/* 449 * ipv6 specific rules here... 450 */ 451static __inline int 452icmp6type_match (int type, ipfw_insn_u32 *cmd) 453{ 454 return (type <= ICMP6_MAXTYPE && (cmd->d[type/32] & (1<<(type%32)) ) ); 455} 456 457static int 458flow6id_match( int curr_flow, ipfw_insn_u32 *cmd ) 459{ 460 int i; 461 for (i=0; i <= cmd->o.arg1; ++i ) 462 if (curr_flow == cmd->d[i] ) 463 return 1; 464 return 0; 465} 466 467/* support for IP6_*_ME opcodes */ 468static int 469search_ip6_addr_net (struct in6_addr * ip6_addr) 470{ 471 struct ifnet *mdc; 472 struct ifaddr *mdc2; 473 struct in6_ifaddr *fdm; 474 struct in6_addr copia; 475 476 TAILQ_FOREACH(mdc, &V_ifnet, if_link) { 477 if_addr_rlock(mdc); 478 TAILQ_FOREACH(mdc2, &mdc->if_addrhead, ifa_link) { 479 if (mdc2->ifa_addr->sa_family == AF_INET6) { 480 fdm = (struct in6_ifaddr *)mdc2; 481 copia = fdm->ia_addr.sin6_addr; 482 /* need for leaving scope_id in the sock_addr */ 483 in6_clearscope(&copia); 484 if (IN6_ARE_ADDR_EQUAL(ip6_addr, &copia)) { 485 if_addr_runlock(mdc); 486 return 1; 487 } 488 } 489 } 490 if_addr_runlock(mdc); 491 } 492 return 0; 493} 494 495static int 496verify_path6(struct in6_addr *src, struct ifnet *ifp) 497{ 498 struct route_in6 ro; 499 struct sockaddr_in6 *dst; 500 501 bzero(&ro, sizeof(ro)); 502 503 dst = (struct sockaddr_in6 * )&(ro.ro_dst); 504 dst->sin6_family = AF_INET6; 505 dst->sin6_len = sizeof(*dst); 506 dst->sin6_addr = *src; 507 /* XXX MRT 0 for ipv6 at this time */ 508 rtalloc_ign((struct route *)&ro, 0); 509 510 if (ro.ro_rt == NULL) 511 return 0; 512 513 /* 514 * if ifp is provided, check for equality with rtentry 515 * We should use rt->rt_ifa->ifa_ifp, instead of rt->rt_ifp, 516 * to support the case of sending packets to an address of our own. 517 * (where the former interface is the first argument of if_simloop() 518 * (=ifp), the latter is lo0) 519 */ 520 if (ifp != NULL && ro.ro_rt->rt_ifa->ifa_ifp != ifp) { 521 RTFREE(ro.ro_rt); 522 return 0; 523 } 524 525 /* if no ifp provided, check if rtentry is not default route */ 526 if (ifp == NULL && 527 IN6_IS_ADDR_UNSPECIFIED(&satosin6(rt_key(ro.ro_rt))->sin6_addr)) { 528 RTFREE(ro.ro_rt); 529 return 0; 530 } 531 532 /* or if this is a blackhole/reject route */ 533 if (ifp == NULL && ro.ro_rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 534 RTFREE(ro.ro_rt); 535 return 0; 536 } 537 538 /* found valid route */ 539 RTFREE(ro.ro_rt); 540 return 1; 541 542} 543 544static int 545is_icmp6_query(int icmp6_type) 546{ 547 if ((icmp6_type <= ICMP6_MAXTYPE) && 548 (icmp6_type == ICMP6_ECHO_REQUEST || 549 icmp6_type == ICMP6_MEMBERSHIP_QUERY || 550 icmp6_type == ICMP6_WRUREQUEST || 551 icmp6_type == ICMP6_FQDN_QUERY || 552 icmp6_type == ICMP6_NI_QUERY)) 553 return (1); 554 555 return (0); 556} 557 558static void 559send_reject6(struct ip_fw_args *args, int code, u_int hlen, struct ip6_hdr *ip6) 560{ 561 struct mbuf *m; 562 563 m = args->m; 564 if (code == ICMP6_UNREACH_RST && args->f_id.proto == IPPROTO_TCP) { 565 struct tcphdr *tcp; 566 tcp = (struct tcphdr *)((char *)ip6 + hlen); 567 568 if ((tcp->th_flags & TH_RST) == 0) { 569 struct mbuf *m0; 570 m0 = ipfw_send_pkt(args->m, &(args->f_id), 571 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 572 tcp->th_flags | TH_RST); 573 if (m0 != NULL) 574 ip6_output(m0, NULL, NULL, 0, NULL, NULL, 575 NULL); 576 } 577 FREE_PKT(m); 578 } else if (code != ICMP6_UNREACH_RST) { /* Send an ICMPv6 unreach. */ 579#if 0 580 /* 581 * Unlike above, the mbufs need to line up with the ip6 hdr, 582 * as the contents are read. We need to m_adj() the 583 * needed amount. 584 * The mbuf will however be thrown away so we can adjust it. 585 * Remember we did an m_pullup on it already so we 586 * can make some assumptions about contiguousness. 587 */ 588 if (args->L3offset) 589 m_adj(m, args->L3offset); 590#endif 591 icmp6_error(m, ICMP6_DST_UNREACH, code, 0); 592 } else 593 FREE_PKT(m); 594 595 args->m = NULL; 596} 597 598#endif /* INET6 */ 599 600 601/* 602 * sends a reject message, consuming the mbuf passed as an argument. 603 */ 604static void 605send_reject(struct ip_fw_args *args, int code, int iplen, struct ip *ip) 606{ 607 608#if 0 609 /* XXX When ip is not guaranteed to be at mtod() we will 610 * need to account for this */ 611 * The mbuf will however be thrown away so we can adjust it. 612 * Remember we did an m_pullup on it already so we 613 * can make some assumptions about contiguousness. 614 */ 615 if (args->L3offset) 616 m_adj(m, args->L3offset); 617#endif 618 if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */ 619 /* We need the IP header in host order for icmp_error(). */ 620 SET_HOST_IPLEN(ip); 621 icmp_error(args->m, ICMP_UNREACH, code, 0L, 0); 622 } else if (args->f_id.proto == IPPROTO_TCP) { 623 struct tcphdr *const tcp = 624 L3HDR(struct tcphdr, mtod(args->m, struct ip *)); 625 if ( (tcp->th_flags & TH_RST) == 0) { 626 struct mbuf *m; 627 m = ipfw_send_pkt(args->m, &(args->f_id), 628 ntohl(tcp->th_seq), ntohl(tcp->th_ack), 629 tcp->th_flags | TH_RST); 630 if (m != NULL) 631 ip_output(m, NULL, NULL, 0, NULL, NULL); 632 } 633 FREE_PKT(args->m); 634 } else 635 FREE_PKT(args->m); 636 args->m = NULL; 637} 638 639/* 640 * Support for uid/gid/jail lookup. These tests are expensive 641 * (because we may need to look into the list of active sockets) 642 * so we cache the results. ugid_lookupp is 0 if we have not 643 * yet done a lookup, 1 if we succeeded, and -1 if we tried 644 * and failed. The function always returns the match value. 645 * We could actually spare the variable and use *uc, setting 646 * it to '(void *)check_uidgid if we have no info, NULL if 647 * we tried and failed, or any other value if successful. 648 */ 649static int 650check_uidgid(ipfw_insn_u32 *insn, struct ip_fw_args *args, int *ugid_lookupp, 651 struct ucred **uc) 652{ 653#ifndef __FreeBSD__ 654 /* XXX */ 655 return cred_check(insn, proto, oif, 656 dst_ip, dst_port, src_ip, src_port, 657 (struct bsd_ucred *)uc, ugid_lookupp, ((struct mbuf *)inp)->m_skb); 658#else /* FreeBSD */ 659 struct in_addr src_ip, dst_ip; 660 struct inpcbinfo *pi; 661 struct ipfw_flow_id *id; 662 struct inpcb *pcb, *inp; 663 struct ifnet *oif; 664 int lookupflags; 665 int match; 666 667 id = &args->f_id; 668 inp = args->inp; 669 oif = args->oif; 670 671 /* 672 * Check to see if the UDP or TCP stack supplied us with 673 * the PCB. If so, rather then holding a lock and looking 674 * up the PCB, we can use the one that was supplied. 675 */ 676 if (inp && *ugid_lookupp == 0) { 677 INP_LOCK_ASSERT(inp); 678 if (inp->inp_socket != NULL) { 679 *uc = crhold(inp->inp_cred); 680 *ugid_lookupp = 1; 681 } else 682 *ugid_lookupp = -1; 683 } 684 /* 685 * If we have already been here and the packet has no 686 * PCB entry associated with it, then we can safely 687 * assume that this is a no match. 688 */ 689 if (*ugid_lookupp == -1) 690 return (0); 691 if (id->proto == IPPROTO_TCP) { 692 lookupflags = 0; 693 pi = &V_tcbinfo; 694 } else if (id->proto == IPPROTO_UDP) { 695 lookupflags = INPLOOKUP_WILDCARD; 696 pi = &V_udbinfo; 697 } else 698 return 0; 699 lookupflags |= INPLOOKUP_RLOCKPCB; 700 match = 0; 701 if (*ugid_lookupp == 0) { 702 if (id->addr_type == 6) { 703#ifdef INET6 704 if (oif == NULL) 705 pcb = in6_pcblookup_mbuf(pi, 706 &id->src_ip6, htons(id->src_port), 707 &id->dst_ip6, htons(id->dst_port), 708 lookupflags, oif, args->m); 709 else 710 pcb = in6_pcblookup_mbuf(pi, 711 &id->dst_ip6, htons(id->dst_port), 712 &id->src_ip6, htons(id->src_port), 713 lookupflags, oif, args->m); 714#else 715 *ugid_lookupp = -1; 716 return (0); 717#endif 718 } else { 719 src_ip.s_addr = htonl(id->src_ip); 720 dst_ip.s_addr = htonl(id->dst_ip); 721 if (oif == NULL) 722 pcb = in_pcblookup_mbuf(pi, 723 src_ip, htons(id->src_port), 724 dst_ip, htons(id->dst_port), 725 lookupflags, oif, args->m); 726 else 727 pcb = in_pcblookup_mbuf(pi, 728 dst_ip, htons(id->dst_port), 729 src_ip, htons(id->src_port), 730 lookupflags, oif, args->m); 731 } 732 if (pcb != NULL) { 733 INP_RLOCK_ASSERT(pcb); 734 *uc = crhold(pcb->inp_cred); 735 *ugid_lookupp = 1; 736 INP_RUNLOCK(pcb); 737 } 738 if (*ugid_lookupp == 0) { 739 /* 740 * We tried and failed, set the variable to -1 741 * so we will not try again on this packet. 742 */ 743 *ugid_lookupp = -1; 744 return (0); 745 } 746 } 747 if (insn->o.opcode == O_UID) 748 match = ((*uc)->cr_uid == (uid_t)insn->d[0]); 749 else if (insn->o.opcode == O_GID) 750 match = groupmember((gid_t)insn->d[0], *uc); 751 else if (insn->o.opcode == O_JAIL) 752 match = ((*uc)->cr_prison->pr_id == (int)insn->d[0]); 753 return (match); 754#endif /* __FreeBSD__ */ 755} 756 757/* 758 * Helper function to set args with info on the rule after the matching 759 * one. slot is precise, whereas we guess rule_id as they are 760 * assigned sequentially. 761 */ 762static inline void 763set_match(struct ip_fw_args *args, int slot, 764 struct ip_fw_chain *chain) 765{ 766 args->rule.chain_id = chain->id; 767 args->rule.slot = slot + 1; /* we use 0 as a marker */ 768 args->rule.rule_id = 1 + chain->map[slot]->id; 769 args->rule.rulenum = chain->map[slot]->rulenum; 770} 771 772/* 773 * The main check routine for the firewall. 774 * 775 * All arguments are in args so we can modify them and return them 776 * back to the caller. 777 * 778 * Parameters: 779 * 780 * args->m (in/out) The packet; we set to NULL when/if we nuke it. 781 * Starts with the IP header. 782 * args->eh (in) Mac header if present, NULL for layer3 packet. 783 * args->L3offset Number of bytes bypassed if we came from L2. 784 * e.g. often sizeof(eh) ** NOTYET ** 785 * args->oif Outgoing interface, NULL if packet is incoming. 786 * The incoming interface is in the mbuf. (in) 787 * args->divert_rule (in/out) 788 * Skip up to the first rule past this rule number; 789 * upon return, non-zero port number for divert or tee. 790 * 791 * args->rule Pointer to the last matching rule (in/out) 792 * args->next_hop Socket we are forwarding to (out). 793 * args->f_id Addresses grabbed from the packet (out) 794 * args->rule.info a cookie depending on rule action 795 * 796 * Return value: 797 * 798 * IP_FW_PASS the packet must be accepted 799 * IP_FW_DENY the packet must be dropped 800 * IP_FW_DIVERT divert packet, port in m_tag 801 * IP_FW_TEE tee packet, port in m_tag 802 * IP_FW_DUMMYNET to dummynet, pipe in args->cookie 803 * IP_FW_NETGRAPH into netgraph, cookie args->cookie 804 * args->rule contains the matching rule, 805 * args->rule.info has additional information. 806 * 807 */ 808int 809ipfw_chk(struct ip_fw_args *args) 810{ 811 812 /* 813 * Local variables holding state while processing a packet: 814 * 815 * IMPORTANT NOTE: to speed up the processing of rules, there 816 * are some assumption on the values of the variables, which 817 * are documented here. Should you change them, please check 818 * the implementation of the various instructions to make sure 819 * that they still work. 820 * 821 * args->eh The MAC header. It is non-null for a layer2 822 * packet, it is NULL for a layer-3 packet. 823 * **notyet** 824 * args->L3offset Offset in the packet to the L3 (IP or equiv.) header. 825 * 826 * m | args->m Pointer to the mbuf, as received from the caller. 827 * It may change if ipfw_chk() does an m_pullup, or if it 828 * consumes the packet because it calls send_reject(). 829 * XXX This has to change, so that ipfw_chk() never modifies 830 * or consumes the buffer. 831 * ip is the beginning of the ip(4 or 6) header. 832 * Calculated by adding the L3offset to the start of data. 833 * (Until we start using L3offset, the packet is 834 * supposed to start with the ip header). 835 */ 836 struct mbuf *m = args->m; 837 struct ip *ip = mtod(m, struct ip *); 838 839 /* 840 * For rules which contain uid/gid or jail constraints, cache 841 * a copy of the users credentials after the pcb lookup has been 842 * executed. This will speed up the processing of rules with 843 * these types of constraints, as well as decrease contention 844 * on pcb related locks. 845 */ 846#ifndef __FreeBSD__ 847 struct bsd_ucred ucred_cache; 848#else 849 struct ucred *ucred_cache = NULL; 850#endif 851 int ucred_lookup = 0; 852 853 /* 854 * oif | args->oif If NULL, ipfw_chk has been called on the 855 * inbound path (ether_input, ip_input). 856 * If non-NULL, ipfw_chk has been called on the outbound path 857 * (ether_output, ip_output). 858 */ 859 struct ifnet *oif = args->oif; 860 861 int f_pos = 0; /* index of current rule in the array */ 862 int retval = 0; 863 864 /* 865 * hlen The length of the IP header. 866 */ 867 u_int hlen = 0; /* hlen >0 means we have an IP pkt */ 868 869 /* 870 * offset The offset of a fragment. offset != 0 means that 871 * we have a fragment at this offset of an IPv4 packet. 872 * offset == 0 means that (if this is an IPv4 packet) 873 * this is the first or only fragment. 874 * For IPv6 offset == 0 means there is no Fragment Header. 875 * If offset != 0 for IPv6 always use correct mask to 876 * get the correct offset because we add IP6F_MORE_FRAG 877 * to be able to dectect the first fragment which would 878 * otherwise have offset = 0. 879 */ 880 u_short offset = 0; 881 882 /* 883 * Local copies of addresses. They are only valid if we have 884 * an IP packet. 885 * 886 * proto The protocol. Set to 0 for non-ip packets, 887 * or to the protocol read from the packet otherwise. 888 * proto != 0 means that we have an IPv4 packet. 889 * 890 * src_port, dst_port port numbers, in HOST format. Only 891 * valid for TCP and UDP packets. 892 * 893 * src_ip, dst_ip ip addresses, in NETWORK format. 894 * Only valid for IPv4 packets. 895 */ 896 uint8_t proto; 897 uint16_t src_port = 0, dst_port = 0; /* NOTE: host format */ 898 struct in_addr src_ip, dst_ip; /* NOTE: network format */ 899 uint16_t iplen=0; 900 int pktlen; 901 uint16_t etype = 0; /* Host order stored ether type */ 902 903 /* 904 * dyn_dir = MATCH_UNKNOWN when rules unchecked, 905 * MATCH_NONE when checked and not matched (q = NULL), 906 * MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL) 907 */ 908 int dyn_dir = MATCH_UNKNOWN; 909 ipfw_dyn_rule *q = NULL; 910 struct ip_fw_chain *chain = &V_layer3_chain; 911 912 /* 913 * We store in ulp a pointer to the upper layer protocol header. 914 * In the ipv4 case this is easy to determine from the header, 915 * but for ipv6 we might have some additional headers in the middle. 916 * ulp is NULL if not found. 917 */ 918 void *ulp = NULL; /* upper layer protocol pointer. */ 919 920 /* XXX ipv6 variables */ 921 int is_ipv6 = 0; 922 uint8_t icmp6_type = 0; 923 uint16_t ext_hd = 0; /* bits vector for extension header filtering */ 924 /* end of ipv6 variables */ 925 926 int is_ipv4 = 0; 927 928 int done = 0; /* flag to exit the outer loop */ 929 930 if (m->m_flags & M_SKIP_FIREWALL || (! V_ipfw_vnet_ready)) 931 return (IP_FW_PASS); /* accept */ 932 933 dst_ip.s_addr = 0; /* make sure it is initialized */ 934 src_ip.s_addr = 0; /* make sure it is initialized */ 935 pktlen = m->m_pkthdr.len; 936 args->f_id.fib = M_GETFIB(m); /* note mbuf not altered) */ 937 proto = args->f_id.proto = 0; /* mark f_id invalid */ 938 /* XXX 0 is a valid proto: IP/IPv6 Hop-by-Hop Option */ 939 940/* 941 * PULLUP_TO(len, p, T) makes sure that len + sizeof(T) is contiguous, 942 * then it sets p to point at the offset "len" in the mbuf. WARNING: the 943 * pointer might become stale after other pullups (but we never use it 944 * this way). 945 */ 946#define PULLUP_TO(_len, p, T) PULLUP_LEN(_len, p, sizeof(T)) 947#define PULLUP_LEN(_len, p, T) \ 948do { \ 949 int x = (_len) + T; \ 950 if ((m)->m_len < x) { \ 951 args->m = m = m_pullup(m, x); \ 952 if (m == NULL) \ 953 goto pullup_failed; \ 954 } \ 955 p = (mtod(m, char *) + (_len)); \ 956} while (0) 957 958 /* 959 * if we have an ether header, 960 */ 961 if (args->eh) 962 etype = ntohs(args->eh->ether_type); 963 964 /* Identify IP packets and fill up variables. */ 965 if (pktlen >= sizeof(struct ip6_hdr) && 966 (args->eh == NULL || etype == ETHERTYPE_IPV6) && ip->ip_v == 6) { 967 struct ip6_hdr *ip6 = (struct ip6_hdr *)ip; 968 is_ipv6 = 1; 969 args->f_id.addr_type = 6; 970 hlen = sizeof(struct ip6_hdr); 971 proto = ip6->ip6_nxt; 972 973 /* Search extension headers to find upper layer protocols */ 974 while (ulp == NULL) { 975 switch (proto) { 976 case IPPROTO_ICMPV6: 977 PULLUP_TO(hlen, ulp, struct icmp6_hdr); 978 icmp6_type = ICMP6(ulp)->icmp6_type; 979 break; 980 981 case IPPROTO_TCP: 982 PULLUP_TO(hlen, ulp, struct tcphdr); 983 dst_port = TCP(ulp)->th_dport; 984 src_port = TCP(ulp)->th_sport; 985 /* save flags for dynamic rules */ 986 args->f_id._flags = TCP(ulp)->th_flags; 987 break; 988 989 case IPPROTO_SCTP: 990 PULLUP_TO(hlen, ulp, struct sctphdr); 991 src_port = SCTP(ulp)->src_port; 992 dst_port = SCTP(ulp)->dest_port; 993 break; 994 995 case IPPROTO_UDP: 996 PULLUP_TO(hlen, ulp, struct udphdr); 997 dst_port = UDP(ulp)->uh_dport; 998 src_port = UDP(ulp)->uh_sport; 999 break; 1000 1001 case IPPROTO_HOPOPTS: /* RFC 2460 */ 1002 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1003 ext_hd |= EXT_HOPOPTS; 1004 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1005 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1006 ulp = NULL; 1007 break; 1008 1009 case IPPROTO_ROUTING: /* RFC 2460 */ 1010 PULLUP_TO(hlen, ulp, struct ip6_rthdr); 1011 switch (((struct ip6_rthdr *)ulp)->ip6r_type) { 1012 case 0: 1013 ext_hd |= EXT_RTHDR0; 1014 break; 1015 case 2: 1016 ext_hd |= EXT_RTHDR2; 1017 break; 1018 default: 1019 printf("IPFW2: IPV6 - Unknown Routing " 1020 "Header type(%d)\n", 1021 ((struct ip6_rthdr *)ulp)->ip6r_type); 1022 if (V_fw_deny_unknown_exthdrs) 1023 return (IP_FW_DENY); 1024 break; 1025 } 1026 ext_hd |= EXT_ROUTING; 1027 hlen += (((struct ip6_rthdr *)ulp)->ip6r_len + 1) << 3; 1028 proto = ((struct ip6_rthdr *)ulp)->ip6r_nxt; 1029 ulp = NULL; 1030 break; 1031 1032 case IPPROTO_FRAGMENT: /* RFC 2460 */ 1033 PULLUP_TO(hlen, ulp, struct ip6_frag); 1034 ext_hd |= EXT_FRAGMENT; 1035 hlen += sizeof (struct ip6_frag); 1036 proto = ((struct ip6_frag *)ulp)->ip6f_nxt; 1037 offset = ((struct ip6_frag *)ulp)->ip6f_offlg & 1038 IP6F_OFF_MASK; 1039 /* Add IP6F_MORE_FRAG for offset of first 1040 * fragment to be != 0. */ 1041 offset |= ((struct ip6_frag *)ulp)->ip6f_offlg & 1042 IP6F_MORE_FRAG; 1043 if (offset == 0) { 1044 printf("IPFW2: IPV6 - Invalid Fragment " 1045 "Header\n"); 1046 if (V_fw_deny_unknown_exthdrs) 1047 return (IP_FW_DENY); 1048 break; 1049 } 1050 args->f_id.extra = 1051 ntohl(((struct ip6_frag *)ulp)->ip6f_ident); 1052 ulp = NULL; 1053 break; 1054 1055 case IPPROTO_DSTOPTS: /* RFC 2460 */ 1056 PULLUP_TO(hlen, ulp, struct ip6_hbh); 1057 ext_hd |= EXT_DSTOPTS; 1058 hlen += (((struct ip6_hbh *)ulp)->ip6h_len + 1) << 3; 1059 proto = ((struct ip6_hbh *)ulp)->ip6h_nxt; 1060 ulp = NULL; 1061 break; 1062 1063 case IPPROTO_AH: /* RFC 2402 */ 1064 PULLUP_TO(hlen, ulp, struct ip6_ext); 1065 ext_hd |= EXT_AH; 1066 hlen += (((struct ip6_ext *)ulp)->ip6e_len + 2) << 2; 1067 proto = ((struct ip6_ext *)ulp)->ip6e_nxt; 1068 ulp = NULL; 1069 break; 1070 1071 case IPPROTO_ESP: /* RFC 2406 */ 1072 PULLUP_TO(hlen, ulp, uint32_t); /* SPI, Seq# */ 1073 /* Anything past Seq# is variable length and 1074 * data past this ext. header is encrypted. */ 1075 ext_hd |= EXT_ESP; 1076 break; 1077 1078 case IPPROTO_NONE: /* RFC 2460 */ 1079 /* 1080 * Packet ends here, and IPv6 header has 1081 * already been pulled up. If ip6e_len!=0 1082 * then octets must be ignored. 1083 */ 1084 ulp = ip; /* non-NULL to get out of loop. */ 1085 break; 1086 1087 case IPPROTO_OSPFIGP: 1088 /* XXX OSPF header check? */ 1089 PULLUP_TO(hlen, ulp, struct ip6_ext); 1090 break; 1091 1092 case IPPROTO_PIM: 1093 /* XXX PIM header check? */ 1094 PULLUP_TO(hlen, ulp, struct pim); 1095 break; 1096 1097 case IPPROTO_CARP: 1098 PULLUP_TO(hlen, ulp, struct carp_header); 1099 if (((struct carp_header *)ulp)->carp_version != 1100 CARP_VERSION) 1101 return (IP_FW_DENY); 1102 if (((struct carp_header *)ulp)->carp_type != 1103 CARP_ADVERTISEMENT) 1104 return (IP_FW_DENY); 1105 break; 1106 1107 case IPPROTO_IPV6: /* RFC 2893 */ 1108 PULLUP_TO(hlen, ulp, struct ip6_hdr); 1109 break; 1110 1111 case IPPROTO_IPV4: /* RFC 2893 */ 1112 PULLUP_TO(hlen, ulp, struct ip); 1113 break; 1114 1115 default: 1116 printf("IPFW2: IPV6 - Unknown Extension " 1117 "Header(%d), ext_hd=%x\n", proto, ext_hd); 1118 if (V_fw_deny_unknown_exthdrs) 1119 return (IP_FW_DENY); 1120 PULLUP_TO(hlen, ulp, struct ip6_ext); 1121 break; 1122 } /*switch */ 1123 } 1124 ip = mtod(m, struct ip *); 1125 ip6 = (struct ip6_hdr *)ip; 1126 args->f_id.src_ip6 = ip6->ip6_src; 1127 args->f_id.dst_ip6 = ip6->ip6_dst; 1128 args->f_id.src_ip = 0; 1129 args->f_id.dst_ip = 0; 1130 args->f_id.flow_id6 = ntohl(ip6->ip6_flow); 1131 } else if (pktlen >= sizeof(struct ip) && 1132 (args->eh == NULL || etype == ETHERTYPE_IP) && ip->ip_v == 4) { 1133 is_ipv4 = 1; 1134 hlen = ip->ip_hl << 2; 1135 args->f_id.addr_type = 4; 1136 1137 /* 1138 * Collect parameters into local variables for faster matching. 1139 */ 1140 proto = ip->ip_p; 1141 src_ip = ip->ip_src; 1142 dst_ip = ip->ip_dst; 1143 offset = ntohs(ip->ip_off) & IP_OFFMASK; 1144 iplen = ntohs(ip->ip_len); 1145 pktlen = iplen < pktlen ? iplen : pktlen; 1146 1147 if (offset == 0) { 1148 switch (proto) { 1149 case IPPROTO_TCP: 1150 PULLUP_TO(hlen, ulp, struct tcphdr); 1151 dst_port = TCP(ulp)->th_dport; 1152 src_port = TCP(ulp)->th_sport; 1153 /* save flags for dynamic rules */ 1154 args->f_id._flags = TCP(ulp)->th_flags; 1155 break; 1156 1157 case IPPROTO_SCTP: 1158 PULLUP_TO(hlen, ulp, struct sctphdr); 1159 src_port = SCTP(ulp)->src_port; 1160 dst_port = SCTP(ulp)->dest_port; 1161 break; 1162 1163 case IPPROTO_UDP: 1164 PULLUP_TO(hlen, ulp, struct udphdr); 1165 dst_port = UDP(ulp)->uh_dport; 1166 src_port = UDP(ulp)->uh_sport; 1167 break; 1168 1169 case IPPROTO_ICMP: 1170 PULLUP_TO(hlen, ulp, struct icmphdr); 1171 //args->f_id.flags = ICMP(ulp)->icmp_type; 1172 break; 1173 1174 default: 1175 break; 1176 } 1177 } 1178 1179 ip = mtod(m, struct ip *); 1180 args->f_id.src_ip = ntohl(src_ip.s_addr); 1181 args->f_id.dst_ip = ntohl(dst_ip.s_addr); 1182 } 1183#undef PULLUP_TO 1184 if (proto) { /* we may have port numbers, store them */ 1185 args->f_id.proto = proto; 1186 args->f_id.src_port = src_port = ntohs(src_port); 1187 args->f_id.dst_port = dst_port = ntohs(dst_port); 1188 } 1189 1190 IPFW_RLOCK(chain); 1191 if (! V_ipfw_vnet_ready) { /* shutting down, leave NOW. */ 1192 IPFW_RUNLOCK(chain); 1193 return (IP_FW_PASS); /* accept */ 1194 } 1195 if (args->rule.slot) { 1196 /* 1197 * Packet has already been tagged as a result of a previous 1198 * match on rule args->rule aka args->rule_id (PIPE, QUEUE, 1199 * REASS, NETGRAPH, DIVERT/TEE...) 1200 * Validate the slot and continue from the next one 1201 * if still present, otherwise do a lookup. 1202 */ 1203 f_pos = (args->rule.chain_id == chain->id) ? 1204 args->rule.slot : 1205 ipfw_find_rule(chain, args->rule.rulenum, 1206 args->rule.rule_id); 1207 } else { 1208 f_pos = 0; 1209 } 1210 1211 /* 1212 * Now scan the rules, and parse microinstructions for each rule. 1213 * We have two nested loops and an inner switch. Sometimes we 1214 * need to break out of one or both loops, or re-enter one of 1215 * the loops with updated variables. Loop variables are: 1216 * 1217 * f_pos (outer loop) points to the current rule. 1218 * On output it points to the matching rule. 1219 * done (outer loop) is used as a flag to break the loop. 1220 * l (inner loop) residual length of current rule. 1221 * cmd points to the current microinstruction. 1222 * 1223 * We break the inner loop by setting l=0 and possibly 1224 * cmdlen=0 if we don't want to advance cmd. 1225 * We break the outer loop by setting done=1 1226 * We can restart the inner loop by setting l>0 and f_pos, f, cmd 1227 * as needed. 1228 */ 1229 for (; f_pos < chain->n_rules; f_pos++) { 1230 ipfw_insn *cmd; 1231 uint32_t tablearg = 0; 1232 int l, cmdlen, skip_or; /* skip rest of OR block */ 1233 struct ip_fw *f; 1234 1235 f = chain->map[f_pos]; 1236 if (V_set_disable & (1 << f->set) ) 1237 continue; 1238 1239 skip_or = 0; 1240 for (l = f->cmd_len, cmd = f->cmd ; l > 0 ; 1241 l -= cmdlen, cmd += cmdlen) { 1242 int match; 1243 1244 /* 1245 * check_body is a jump target used when we find a 1246 * CHECK_STATE, and need to jump to the body of 1247 * the target rule. 1248 */ 1249 1250/* check_body: */ 1251 cmdlen = F_LEN(cmd); 1252 /* 1253 * An OR block (insn_1 || .. || insn_n) has the 1254 * F_OR bit set in all but the last instruction. 1255 * The first match will set "skip_or", and cause 1256 * the following instructions to be skipped until 1257 * past the one with the F_OR bit clear. 1258 */ 1259 if (skip_or) { /* skip this instruction */ 1260 if ((cmd->len & F_OR) == 0) 1261 skip_or = 0; /* next one is good */ 1262 continue; 1263 } 1264 match = 0; /* set to 1 if we succeed */ 1265 1266 switch (cmd->opcode) { 1267 /* 1268 * The first set of opcodes compares the packet's 1269 * fields with some pattern, setting 'match' if a 1270 * match is found. At the end of the loop there is 1271 * logic to deal with F_NOT and F_OR flags associated 1272 * with the opcode. 1273 */ 1274 case O_NOP: 1275 match = 1; 1276 break; 1277 1278 case O_FORWARD_MAC: 1279 printf("ipfw: opcode %d unimplemented\n", 1280 cmd->opcode); 1281 break; 1282 1283 case O_GID: 1284 case O_UID: 1285 case O_JAIL: 1286 /* 1287 * We only check offset == 0 && proto != 0, 1288 * as this ensures that we have a 1289 * packet with the ports info. 1290 */ 1291 if (offset != 0) 1292 break; 1293 if (proto == IPPROTO_TCP || 1294 proto == IPPROTO_UDP) 1295 match = check_uidgid( 1296 (ipfw_insn_u32 *)cmd, 1297 args, &ucred_lookup, 1298#ifdef __FreeBSD__ 1299 &ucred_cache); 1300#else 1301 (void *)&ucred_cache); 1302#endif 1303 break; 1304 1305 case O_RECV: 1306 match = iface_match(m->m_pkthdr.rcvif, 1307 (ipfw_insn_if *)cmd); 1308 break; 1309 1310 case O_XMIT: 1311 match = iface_match(oif, (ipfw_insn_if *)cmd); 1312 break; 1313 1314 case O_VIA: 1315 match = iface_match(oif ? oif : 1316 m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd); 1317 break; 1318 1319 case O_MACADDR2: 1320 if (args->eh != NULL) { /* have MAC header */ 1321 u_int32_t *want = (u_int32_t *) 1322 ((ipfw_insn_mac *)cmd)->addr; 1323 u_int32_t *mask = (u_int32_t *) 1324 ((ipfw_insn_mac *)cmd)->mask; 1325 u_int32_t *hdr = (u_int32_t *)args->eh; 1326 1327 match = 1328 ( want[0] == (hdr[0] & mask[0]) && 1329 want[1] == (hdr[1] & mask[1]) && 1330 want[2] == (hdr[2] & mask[2]) ); 1331 } 1332 break; 1333 1334 case O_MAC_TYPE: 1335 if (args->eh != NULL) { 1336 u_int16_t *p = 1337 ((ipfw_insn_u16 *)cmd)->ports; 1338 int i; 1339 1340 for (i = cmdlen - 1; !match && i>0; 1341 i--, p += 2) 1342 match = (etype >= p[0] && 1343 etype <= p[1]); 1344 } 1345 break; 1346 1347 case O_FRAG: 1348 match = (offset != 0); 1349 break; 1350 1351 case O_IN: /* "out" is "not in" */ 1352 match = (oif == NULL); 1353 break; 1354 1355 case O_LAYER2: 1356 match = (args->eh != NULL); 1357 break; 1358 1359 case O_DIVERTED: 1360 { 1361 /* For diverted packets, args->rule.info 1362 * contains the divert port (in host format) 1363 * reason and direction. 1364 */ 1365 uint32_t i = args->rule.info; 1366 match = (i&IPFW_IS_MASK) == IPFW_IS_DIVERT && 1367 cmd->arg1 & ((i & IPFW_INFO_IN) ? 1 : 2); 1368 } 1369 break; 1370 1371 case O_PROTO: 1372 /* 1373 * We do not allow an arg of 0 so the 1374 * check of "proto" only suffices. 1375 */ 1376 match = (proto == cmd->arg1); 1377 break; 1378 1379 case O_IP_SRC: 1380 match = is_ipv4 && 1381 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1382 src_ip.s_addr); 1383 break; 1384 1385 case O_IP_SRC_LOOKUP: 1386 case O_IP_DST_LOOKUP: 1387 if (is_ipv4) { 1388 uint32_t key = 1389 (cmd->opcode == O_IP_DST_LOOKUP) ? 1390 dst_ip.s_addr : src_ip.s_addr; 1391 uint32_t v = 0; 1392 1393 if (cmdlen > F_INSN_SIZE(ipfw_insn_u32)) { 1394 /* generic lookup. The key must be 1395 * in 32bit big-endian format. 1396 */ 1397 v = ((ipfw_insn_u32 *)cmd)->d[1]; 1398 if (v == 0) 1399 key = dst_ip.s_addr; 1400 else if (v == 1) 1401 key = src_ip.s_addr; 1402 else if (v == 6) /* dscp */ 1403 key = (ip->ip_tos >> 2) & 0x3f; 1404 else if (offset != 0) 1405 break; 1406 else if (proto != IPPROTO_TCP && 1407 proto != IPPROTO_UDP) 1408 break; 1409 else if (v == 2) 1410 key = htonl(dst_port); 1411 else if (v == 3) 1412 key = htonl(src_port); 1413 else if (v == 4 || v == 5) { 1414 check_uidgid( 1415 (ipfw_insn_u32 *)cmd, 1416 args, &ucred_lookup, 1417#ifdef __FreeBSD__ 1418 &ucred_cache); 1419 if (v == 4 /* O_UID */) 1420 key = ucred_cache->cr_uid; 1421 else if (v == 5 /* O_JAIL */) 1422 key = ucred_cache->cr_prison->pr_id; 1423#else /* !__FreeBSD__ */ 1424 (void *)&ucred_cache); 1425 if (v ==4 /* O_UID */) 1426 key = ucred_cache.uid; 1427 else if (v == 5 /* O_JAIL */) 1428 key = ucred_cache.xid; 1429#endif /* !__FreeBSD__ */ 1430 key = htonl(key); 1431 } else 1432 break; 1433 } 1434 match = ipfw_lookup_table(chain, 1435 cmd->arg1, key, &v); 1436 if (!match) 1437 break; 1438 if (cmdlen == F_INSN_SIZE(ipfw_insn_u32)) 1439 match = 1440 ((ipfw_insn_u32 *)cmd)->d[0] == v; 1441 else 1442 tablearg = v; 1443 } 1444 break; 1445 1446 case O_IP_SRC_MASK: 1447 case O_IP_DST_MASK: 1448 if (is_ipv4) { 1449 uint32_t a = 1450 (cmd->opcode == O_IP_DST_MASK) ? 1451 dst_ip.s_addr : src_ip.s_addr; 1452 uint32_t *p = ((ipfw_insn_u32 *)cmd)->d; 1453 int i = cmdlen-1; 1454 1455 for (; !match && i>0; i-= 2, p+= 2) 1456 match = (p[0] == (a & p[1])); 1457 } 1458 break; 1459 1460 case O_IP_SRC_ME: 1461 if (is_ipv4) { 1462 struct ifnet *tif; 1463 1464 INADDR_TO_IFP(src_ip, tif); 1465 match = (tif != NULL); 1466 break; 1467 } 1468#ifdef INET6 1469 /* FALLTHROUGH */ 1470 case O_IP6_SRC_ME: 1471 match= is_ipv6 && search_ip6_addr_net(&args->f_id.src_ip6); 1472#endif 1473 break; 1474 1475 case O_IP_DST_SET: 1476 case O_IP_SRC_SET: 1477 if (is_ipv4) { 1478 u_int32_t *d = (u_int32_t *)(cmd+1); 1479 u_int32_t addr = 1480 cmd->opcode == O_IP_DST_SET ? 1481 args->f_id.dst_ip : 1482 args->f_id.src_ip; 1483 1484 if (addr < d[0]) 1485 break; 1486 addr -= d[0]; /* subtract base */ 1487 match = (addr < cmd->arg1) && 1488 ( d[ 1 + (addr>>5)] & 1489 (1<<(addr & 0x1f)) ); 1490 } 1491 break; 1492 1493 case O_IP_DST: 1494 match = is_ipv4 && 1495 (((ipfw_insn_ip *)cmd)->addr.s_addr == 1496 dst_ip.s_addr); 1497 break; 1498 1499 case O_IP_DST_ME: 1500 if (is_ipv4) { 1501 struct ifnet *tif; 1502 1503 INADDR_TO_IFP(dst_ip, tif); 1504 match = (tif != NULL); 1505 break; 1506 } 1507#ifdef INET6 1508 /* FALLTHROUGH */ 1509 case O_IP6_DST_ME: 1510 match= is_ipv6 && search_ip6_addr_net(&args->f_id.dst_ip6); 1511#endif 1512 break; 1513 1514 1515 case O_IP_SRCPORT: 1516 case O_IP_DSTPORT: 1517 /* 1518 * offset == 0 && proto != 0 is enough 1519 * to guarantee that we have a 1520 * packet with port info. 1521 */ 1522 if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP) 1523 && offset == 0) { 1524 u_int16_t x = 1525 (cmd->opcode == O_IP_SRCPORT) ? 1526 src_port : dst_port ; 1527 u_int16_t *p = 1528 ((ipfw_insn_u16 *)cmd)->ports; 1529 int i; 1530 1531 for (i = cmdlen - 1; !match && i>0; 1532 i--, p += 2) 1533 match = (x>=p[0] && x<=p[1]); 1534 } 1535 break; 1536 1537 case O_ICMPTYPE: 1538 match = (offset == 0 && proto==IPPROTO_ICMP && 1539 icmptype_match(ICMP(ulp), (ipfw_insn_u32 *)cmd) ); 1540 break; 1541 1542#ifdef INET6 1543 case O_ICMP6TYPE: 1544 match = is_ipv6 && offset == 0 && 1545 proto==IPPROTO_ICMPV6 && 1546 icmp6type_match( 1547 ICMP6(ulp)->icmp6_type, 1548 (ipfw_insn_u32 *)cmd); 1549 break; 1550#endif /* INET6 */ 1551 1552 case O_IPOPT: 1553 match = (is_ipv4 && 1554 ipopts_match(ip, cmd) ); 1555 break; 1556 1557 case O_IPVER: 1558 match = (is_ipv4 && 1559 cmd->arg1 == ip->ip_v); 1560 break; 1561 1562 case O_IPID: 1563 case O_IPLEN: 1564 case O_IPTTL: 1565 if (is_ipv4) { /* only for IP packets */ 1566 uint16_t x; 1567 uint16_t *p; 1568 int i; 1569 1570 if (cmd->opcode == O_IPLEN) 1571 x = iplen; 1572 else if (cmd->opcode == O_IPTTL) 1573 x = ip->ip_ttl; 1574 else /* must be IPID */ 1575 x = ntohs(ip->ip_id); 1576 if (cmdlen == 1) { 1577 match = (cmd->arg1 == x); 1578 break; 1579 } 1580 /* otherwise we have ranges */ 1581 p = ((ipfw_insn_u16 *)cmd)->ports; 1582 i = cmdlen - 1; 1583 for (; !match && i>0; i--, p += 2) 1584 match = (x >= p[0] && x <= p[1]); 1585 } 1586 break; 1587 1588 case O_IPPRECEDENCE: 1589 match = (is_ipv4 && 1590 (cmd->arg1 == (ip->ip_tos & 0xe0)) ); 1591 break; 1592 1593 case O_IPTOS: 1594 match = (is_ipv4 && 1595 flags_match(cmd, ip->ip_tos)); 1596 break; 1597 1598 case O_TCPDATALEN: 1599 if (proto == IPPROTO_TCP && offset == 0) { 1600 struct tcphdr *tcp; 1601 uint16_t x; 1602 uint16_t *p; 1603 int i; 1604 1605 tcp = TCP(ulp); 1606 x = iplen - 1607 ((ip->ip_hl + tcp->th_off) << 2); 1608 if (cmdlen == 1) { 1609 match = (cmd->arg1 == x); 1610 break; 1611 } 1612 /* otherwise we have ranges */ 1613 p = ((ipfw_insn_u16 *)cmd)->ports; 1614 i = cmdlen - 1; 1615 for (; !match && i>0; i--, p += 2) 1616 match = (x >= p[0] && x <= p[1]); 1617 } 1618 break; 1619 1620 case O_TCPFLAGS: 1621 match = (proto == IPPROTO_TCP && offset == 0 && 1622 flags_match(cmd, TCP(ulp)->th_flags)); 1623 break; 1624 1625 case O_TCPOPTS: 1626 PULLUP_LEN(hlen, ulp, (TCP(ulp)->th_off << 2)); 1627 match = (proto == IPPROTO_TCP && offset == 0 && 1628 tcpopts_match(TCP(ulp), cmd)); 1629 break; 1630 1631 case O_TCPSEQ: 1632 match = (proto == IPPROTO_TCP && offset == 0 && 1633 ((ipfw_insn_u32 *)cmd)->d[0] == 1634 TCP(ulp)->th_seq); 1635 break; 1636 1637 case O_TCPACK: 1638 match = (proto == IPPROTO_TCP && offset == 0 && 1639 ((ipfw_insn_u32 *)cmd)->d[0] == 1640 TCP(ulp)->th_ack); 1641 break; 1642 1643 case O_TCPWIN: 1644 match = (proto == IPPROTO_TCP && offset == 0 && 1645 cmd->arg1 == TCP(ulp)->th_win); 1646 break; 1647 1648 case O_ESTAB: 1649 /* reject packets which have SYN only */ 1650 /* XXX should i also check for TH_ACK ? */ 1651 match = (proto == IPPROTO_TCP && offset == 0 && 1652 (TCP(ulp)->th_flags & 1653 (TH_RST | TH_ACK | TH_SYN)) != TH_SYN); 1654 break; 1655 1656 case O_ALTQ: { 1657 struct pf_mtag *at; 1658 ipfw_insn_altq *altq = (ipfw_insn_altq *)cmd; 1659 1660 match = 1; 1661 at = pf_find_mtag(m); 1662 if (at != NULL && at->qid != 0) 1663 break; 1664 at = pf_get_mtag(m); 1665 if (at == NULL) { 1666 /* 1667 * Let the packet fall back to the 1668 * default ALTQ. 1669 */ 1670 break; 1671 } 1672 at->qid = altq->qid; 1673 if (is_ipv4) 1674 at->af = AF_INET; 1675 else 1676 at->af = AF_LINK; 1677 at->hdr = ip; 1678 break; 1679 } 1680 1681 case O_LOG: 1682 ipfw_log(f, hlen, args, m, 1683 oif, offset, tablearg, ip); 1684 match = 1; 1685 break; 1686 1687 case O_PROB: 1688 match = (random()<((ipfw_insn_u32 *)cmd)->d[0]); 1689 break; 1690 1691 case O_VERREVPATH: 1692 /* Outgoing packets automatically pass/match */ 1693 match = ((oif != NULL) || 1694 (m->m_pkthdr.rcvif == NULL) || 1695 ( 1696#ifdef INET6 1697 is_ipv6 ? 1698 verify_path6(&(args->f_id.src_ip6), 1699 m->m_pkthdr.rcvif) : 1700#endif 1701 verify_path(src_ip, m->m_pkthdr.rcvif, 1702 args->f_id.fib))); 1703 break; 1704 1705 case O_VERSRCREACH: 1706 /* Outgoing packets automatically pass/match */ 1707 match = (hlen > 0 && ((oif != NULL) || 1708#ifdef INET6 1709 is_ipv6 ? 1710 verify_path6(&(args->f_id.src_ip6), 1711 NULL) : 1712#endif 1713 verify_path(src_ip, NULL, args->f_id.fib))); 1714 break; 1715 1716 case O_ANTISPOOF: 1717 /* Outgoing packets automatically pass/match */ 1718 if (oif == NULL && hlen > 0 && 1719 ( (is_ipv4 && in_localaddr(src_ip)) 1720#ifdef INET6 1721 || (is_ipv6 && 1722 in6_localaddr(&(args->f_id.src_ip6))) 1723#endif 1724 )) 1725 match = 1726#ifdef INET6 1727 is_ipv6 ? verify_path6( 1728 &(args->f_id.src_ip6), 1729 m->m_pkthdr.rcvif) : 1730#endif 1731 verify_path(src_ip, 1732 m->m_pkthdr.rcvif, 1733 args->f_id.fib); 1734 else 1735 match = 1; 1736 break; 1737 1738 case O_IPSEC: 1739#ifdef IPSEC 1740 match = (m_tag_find(m, 1741 PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL); 1742#endif 1743 /* otherwise no match */ 1744 break; 1745 1746#ifdef INET6 1747 case O_IP6_SRC: 1748 match = is_ipv6 && 1749 IN6_ARE_ADDR_EQUAL(&args->f_id.src_ip6, 1750 &((ipfw_insn_ip6 *)cmd)->addr6); 1751 break; 1752 1753 case O_IP6_DST: 1754 match = is_ipv6 && 1755 IN6_ARE_ADDR_EQUAL(&args->f_id.dst_ip6, 1756 &((ipfw_insn_ip6 *)cmd)->addr6); 1757 break; 1758 case O_IP6_SRC_MASK: 1759 case O_IP6_DST_MASK: 1760 if (is_ipv6) { 1761 int i = cmdlen - 1; 1762 struct in6_addr p; 1763 struct in6_addr *d = 1764 &((ipfw_insn_ip6 *)cmd)->addr6; 1765 1766 for (; !match && i > 0; d += 2, 1767 i -= F_INSN_SIZE(struct in6_addr) 1768 * 2) { 1769 p = (cmd->opcode == 1770 O_IP6_SRC_MASK) ? 1771 args->f_id.src_ip6: 1772 args->f_id.dst_ip6; 1773 APPLY_MASK(&p, &d[1]); 1774 match = 1775 IN6_ARE_ADDR_EQUAL(&d[0], 1776 &p); 1777 } 1778 } 1779 break; 1780 1781 case O_FLOW6ID: 1782 match = is_ipv6 && 1783 flow6id_match(args->f_id.flow_id6, 1784 (ipfw_insn_u32 *) cmd); 1785 break; 1786 1787 case O_EXT_HDR: 1788 match = is_ipv6 && 1789 (ext_hd & ((ipfw_insn *) cmd)->arg1); 1790 break; 1791 1792 case O_IP6: 1793 match = is_ipv6; 1794 break; 1795#endif 1796 1797 case O_IP4: 1798 match = is_ipv4; 1799 break; 1800 1801 case O_TAG: { 1802 struct m_tag *mtag; 1803 uint32_t tag = (cmd->arg1 == IP_FW_TABLEARG) ? 1804 tablearg : cmd->arg1; 1805 1806 /* Packet is already tagged with this tag? */ 1807 mtag = m_tag_locate(m, MTAG_IPFW, tag, NULL); 1808 1809 /* We have `untag' action when F_NOT flag is 1810 * present. And we must remove this mtag from 1811 * mbuf and reset `match' to zero (`match' will 1812 * be inversed later). 1813 * Otherwise we should allocate new mtag and 1814 * push it into mbuf. 1815 */ 1816 if (cmd->len & F_NOT) { /* `untag' action */ 1817 if (mtag != NULL) 1818 m_tag_delete(m, mtag); 1819 match = 0; 1820 } else { 1821 if (mtag == NULL) { 1822 mtag = m_tag_alloc( MTAG_IPFW, 1823 tag, 0, M_NOWAIT); 1824 if (mtag != NULL) 1825 m_tag_prepend(m, mtag); 1826 } 1827 match = 1; 1828 } 1829 break; 1830 } 1831 1832 case O_FIB: /* try match the specified fib */ 1833 if (args->f_id.fib == cmd->arg1) 1834 match = 1; 1835 break; 1836 1837 case O_SOCKARG: { 1838 struct inpcb *inp = args->inp; 1839 struct inpcbinfo *pi; 1840 1841 if (is_ipv6) /* XXX can we remove this ? */ 1842 break; 1843 1844 if (proto == IPPROTO_TCP) 1845 pi = &V_tcbinfo; 1846 else if (proto == IPPROTO_UDP) 1847 pi = &V_udbinfo; 1848 else 1849 break; 1850 1851 /* 1852 * XXXRW: so_user_cookie should almost 1853 * certainly be inp_user_cookie? 1854 */ 1855 1856 /* For incomming packet, lookup up the 1857 inpcb using the src/dest ip/port tuple */ 1858 if (inp == NULL) { 1859 inp = in_pcblookup(pi, 1860 src_ip, htons(src_port), 1861 dst_ip, htons(dst_port), 1862 INPLOOKUP_RLOCKPCB, NULL); 1863 if (inp != NULL) { 1864 tablearg = 1865 inp->inp_socket->so_user_cookie; 1866 if (tablearg) 1867 match = 1; 1868 INP_RUNLOCK(inp); 1869 } 1870 } else { 1871 if (inp->inp_socket) { 1872 tablearg = 1873 inp->inp_socket->so_user_cookie; 1874 if (tablearg) 1875 match = 1; 1876 } 1877 } 1878 break; 1879 } 1880 1881 case O_TAGGED: { 1882 struct m_tag *mtag; 1883 uint32_t tag = (cmd->arg1 == IP_FW_TABLEARG) ? 1884 tablearg : cmd->arg1; 1885 1886 if (cmdlen == 1) { 1887 match = m_tag_locate(m, MTAG_IPFW, 1888 tag, NULL) != NULL; 1889 break; 1890 } 1891 1892 /* we have ranges */ 1893 for (mtag = m_tag_first(m); 1894 mtag != NULL && !match; 1895 mtag = m_tag_next(m, mtag)) { 1896 uint16_t *p; 1897 int i; 1898 1899 if (mtag->m_tag_cookie != MTAG_IPFW) 1900 continue; 1901 1902 p = ((ipfw_insn_u16 *)cmd)->ports; 1903 i = cmdlen - 1; 1904 for(; !match && i > 0; i--, p += 2) 1905 match = 1906 mtag->m_tag_id >= p[0] && 1907 mtag->m_tag_id <= p[1]; 1908 } 1909 break; 1910 } 1911 1912 /* 1913 * The second set of opcodes represents 'actions', 1914 * i.e. the terminal part of a rule once the packet 1915 * matches all previous patterns. 1916 * Typically there is only one action for each rule, 1917 * and the opcode is stored at the end of the rule 1918 * (but there are exceptions -- see below). 1919 * 1920 * In general, here we set retval and terminate the 1921 * outer loop (would be a 'break 3' in some language, 1922 * but we need to set l=0, done=1) 1923 * 1924 * Exceptions: 1925 * O_COUNT and O_SKIPTO actions: 1926 * instead of terminating, we jump to the next rule 1927 * (setting l=0), or to the SKIPTO target (setting 1928 * f/f_len, cmd and l as needed), respectively. 1929 * 1930 * O_TAG, O_LOG and O_ALTQ action parameters: 1931 * perform some action and set match = 1; 1932 * 1933 * O_LIMIT and O_KEEP_STATE: these opcodes are 1934 * not real 'actions', and are stored right 1935 * before the 'action' part of the rule. 1936 * These opcodes try to install an entry in the 1937 * state tables; if successful, we continue with 1938 * the next opcode (match=1; break;), otherwise 1939 * the packet must be dropped (set retval, 1940 * break loops with l=0, done=1) 1941 * 1942 * O_PROBE_STATE and O_CHECK_STATE: these opcodes 1943 * cause a lookup of the state table, and a jump 1944 * to the 'action' part of the parent rule 1945 * if an entry is found, or 1946 * (CHECK_STATE only) a jump to the next rule if 1947 * the entry is not found. 1948 * The result of the lookup is cached so that 1949 * further instances of these opcodes become NOPs. 1950 * The jump to the next rule is done by setting 1951 * l=0, cmdlen=0. 1952 */ 1953 case O_LIMIT: 1954 case O_KEEP_STATE: 1955 if (ipfw_install_state(f, 1956 (ipfw_insn_limit *)cmd, args, tablearg)) { 1957 /* error or limit violation */ 1958 retval = IP_FW_DENY; 1959 l = 0; /* exit inner loop */ 1960 done = 1; /* exit outer loop */ 1961 } 1962 match = 1; 1963 break; 1964 1965 case O_PROBE_STATE: 1966 case O_CHECK_STATE: 1967 /* 1968 * dynamic rules are checked at the first 1969 * keep-state or check-state occurrence, 1970 * with the result being stored in dyn_dir. 1971 * The compiler introduces a PROBE_STATE 1972 * instruction for us when we have a 1973 * KEEP_STATE (because PROBE_STATE needs 1974 * to be run first). 1975 */ 1976 if (dyn_dir == MATCH_UNKNOWN && 1977 (q = ipfw_lookup_dyn_rule(&args->f_id, 1978 &dyn_dir, proto == IPPROTO_TCP ? 1979 TCP(ulp) : NULL)) 1980 != NULL) { 1981 /* 1982 * Found dynamic entry, update stats 1983 * and jump to the 'action' part of 1984 * the parent rule by setting 1985 * f, cmd, l and clearing cmdlen. 1986 */ 1987 q->pcnt++; 1988 q->bcnt += pktlen; 1989 /* XXX we would like to have f_pos 1990 * readily accessible in the dynamic 1991 * rule, instead of having to 1992 * lookup q->rule. 1993 */ 1994 f = q->rule; 1995 f_pos = ipfw_find_rule(chain, 1996 f->rulenum, f->id); 1997 cmd = ACTION_PTR(f); 1998 l = f->cmd_len - f->act_ofs; 1999 ipfw_dyn_unlock(); 2000 cmdlen = 0; 2001 match = 1; 2002 break; 2003 } 2004 /* 2005 * Dynamic entry not found. If CHECK_STATE, 2006 * skip to next rule, if PROBE_STATE just 2007 * ignore and continue with next opcode. 2008 */ 2009 if (cmd->opcode == O_CHECK_STATE) 2010 l = 0; /* exit inner loop */ 2011 match = 1; 2012 break; 2013 2014 case O_ACCEPT: 2015 retval = 0; /* accept */ 2016 l = 0; /* exit inner loop */ 2017 done = 1; /* exit outer loop */ 2018 break; 2019 2020 case O_PIPE: 2021 case O_QUEUE: 2022 set_match(args, f_pos, chain); 2023 args->rule.info = (cmd->arg1 == IP_FW_TABLEARG) ? 2024 tablearg : cmd->arg1; 2025 if (cmd->opcode == O_PIPE) 2026 args->rule.info |= IPFW_IS_PIPE; 2027 if (V_fw_one_pass) 2028 args->rule.info |= IPFW_ONEPASS; 2029 retval = IP_FW_DUMMYNET; 2030 l = 0; /* exit inner loop */ 2031 done = 1; /* exit outer loop */ 2032 break; 2033 2034 case O_DIVERT: 2035 case O_TEE: 2036 if (args->eh) /* not on layer 2 */ 2037 break; 2038 /* otherwise this is terminal */ 2039 l = 0; /* exit inner loop */ 2040 done = 1; /* exit outer loop */ 2041 retval = (cmd->opcode == O_DIVERT) ? 2042 IP_FW_DIVERT : IP_FW_TEE; 2043 set_match(args, f_pos, chain); 2044 args->rule.info = (cmd->arg1 == IP_FW_TABLEARG) ? 2045 tablearg : cmd->arg1; 2046 break; 2047 2048 case O_COUNT: 2049 f->pcnt++; /* update stats */ 2050 f->bcnt += pktlen; 2051 f->timestamp = time_uptime; 2052 l = 0; /* exit inner loop */ 2053 break; 2054 2055 case O_SKIPTO: 2056 f->pcnt++; /* update stats */ 2057 f->bcnt += pktlen; 2058 f->timestamp = time_uptime; 2059 /* If possible use cached f_pos (in f->next_rule), 2060 * whose version is written in f->next_rule 2061 * (horrible hacks to avoid changing the ABI). 2062 */ 2063 if (cmd->arg1 != IP_FW_TABLEARG && 2064 (uintptr_t)f->x_next == chain->id) { 2065 f_pos = (uintptr_t)f->next_rule; 2066 } else { 2067 int i = (cmd->arg1 == IP_FW_TABLEARG) ? 2068 tablearg : cmd->arg1; 2069 /* make sure we do not jump backward */ 2070 if (i <= f->rulenum) 2071 i = f->rulenum + 1; 2072 f_pos = ipfw_find_rule(chain, i, 0); 2073 /* update the cache */ 2074 if (cmd->arg1 != IP_FW_TABLEARG) { 2075 f->next_rule = 2076 (void *)(uintptr_t)f_pos; 2077 f->x_next = 2078 (void *)(uintptr_t)chain->id; 2079 } 2080 } 2081 /* 2082 * Skip disabled rules, and re-enter 2083 * the inner loop with the correct 2084 * f_pos, f, l and cmd. 2085 * Also clear cmdlen and skip_or 2086 */ 2087 for (; f_pos < chain->n_rules - 1 && 2088 (V_set_disable & 2089 (1 << chain->map[f_pos]->set)); 2090 f_pos++) 2091 ; 2092 /* Re-enter the inner loop at the skipto rule. */ 2093 f = chain->map[f_pos]; 2094 l = f->cmd_len; 2095 cmd = f->cmd; 2096 match = 1; 2097 cmdlen = 0; 2098 skip_or = 0; 2099 continue; 2100 break; /* not reached */ 2101 2102 case O_REJECT: 2103 /* 2104 * Drop the packet and send a reject notice 2105 * if the packet is not ICMP (or is an ICMP 2106 * query), and it is not multicast/broadcast. 2107 */ 2108 if (hlen > 0 && is_ipv4 && offset == 0 && 2109 (proto != IPPROTO_ICMP || 2110 is_icmp_query(ICMP(ulp))) && 2111 !(m->m_flags & (M_BCAST|M_MCAST)) && 2112 !IN_MULTICAST(ntohl(dst_ip.s_addr))) { 2113 send_reject(args, cmd->arg1, iplen, ip); 2114 m = args->m; 2115 } 2116 /* FALLTHROUGH */ 2117#ifdef INET6 2118 case O_UNREACH6: 2119 if (hlen > 0 && is_ipv6 && 2120 ((offset & IP6F_OFF_MASK) == 0) && 2121 (proto != IPPROTO_ICMPV6 || 2122 (is_icmp6_query(icmp6_type) == 1)) && 2123 !(m->m_flags & (M_BCAST|M_MCAST)) && 2124 !IN6_IS_ADDR_MULTICAST(&args->f_id.dst_ip6)) { 2125 send_reject6( 2126 args, cmd->arg1, hlen, 2127 (struct ip6_hdr *)ip); 2128 m = args->m; 2129 } 2130 /* FALLTHROUGH */ 2131#endif 2132 case O_DENY: 2133 retval = IP_FW_DENY; 2134 l = 0; /* exit inner loop */ 2135 done = 1; /* exit outer loop */ 2136 break; 2137 2138 case O_FORWARD_IP: 2139 if (args->eh) /* not valid on layer2 pkts */ 2140 break; 2141 if (q == NULL || q->rule != f || 2142 dyn_dir == MATCH_FORWARD) { 2143 struct sockaddr_in *sa; 2144 sa = &(((ipfw_insn_sa *)cmd)->sa); 2145 if (sa->sin_addr.s_addr == INADDR_ANY) { 2146 bcopy(sa, &args->hopstore, 2147 sizeof(*sa)); 2148 args->hopstore.sin_addr.s_addr = 2149 htonl(tablearg); 2150 args->next_hop = &args->hopstore; 2151 } else { 2152 args->next_hop = sa; 2153 } 2154 } 2155 retval = IP_FW_PASS; 2156 l = 0; /* exit inner loop */ 2157 done = 1; /* exit outer loop */ 2158 break; 2159 2160 case O_NETGRAPH: 2161 case O_NGTEE: 2162 set_match(args, f_pos, chain); 2163 args->rule.info = (cmd->arg1 == IP_FW_TABLEARG) ? 2164 tablearg : cmd->arg1; 2165 if (V_fw_one_pass) 2166 args->rule.info |= IPFW_ONEPASS; 2167 retval = (cmd->opcode == O_NETGRAPH) ? 2168 IP_FW_NETGRAPH : IP_FW_NGTEE; 2169 l = 0; /* exit inner loop */ 2170 done = 1; /* exit outer loop */ 2171 break; 2172 2173 case O_SETFIB: { 2174 uint32_t fib; 2175 2176 f->pcnt++; /* update stats */ 2177 f->bcnt += pktlen; 2178 f->timestamp = time_uptime; 2179 fib = (cmd->arg1 == IP_FW_TABLEARG) ? tablearg: 2180 cmd->arg1; 2181 if (fib >= rt_numfibs) 2182 fib = 0; 2183 M_SETFIB(m, fib); 2184 args->f_id.fib = fib; 2185 l = 0; /* exit inner loop */ 2186 break; 2187 } 2188 2189 case O_NAT: 2190 if (!IPFW_NAT_LOADED) { 2191 retval = IP_FW_DENY; 2192 } else { 2193 struct cfg_nat *t; 2194 int nat_id; 2195 2196 set_match(args, f_pos, chain); 2197 /* Check if this is 'global' nat rule */ 2198 if (cmd->arg1 == 0) { 2199 retval = ipfw_nat_ptr(args, NULL, m); 2200 l = 0; 2201 done = 1; 2202 break; 2203 } 2204 t = ((ipfw_insn_nat *)cmd)->nat; 2205 if (t == NULL) { 2206 nat_id = (cmd->arg1 == IP_FW_TABLEARG) ? 2207 tablearg : cmd->arg1; 2208 t = (*lookup_nat_ptr)(&chain->nat, nat_id); 2209 2210 if (t == NULL) { 2211 retval = IP_FW_DENY; 2212 l = 0; /* exit inner loop */ 2213 done = 1; /* exit outer loop */ 2214 break; 2215 } 2216 if (cmd->arg1 != IP_FW_TABLEARG) 2217 ((ipfw_insn_nat *)cmd)->nat = t; 2218 } 2219 retval = ipfw_nat_ptr(args, t, m); 2220 } 2221 l = 0; /* exit inner loop */ 2222 done = 1; /* exit outer loop */ 2223 break; 2224 2225 case O_REASS: { 2226 int ip_off; 2227 2228 f->pcnt++; 2229 f->bcnt += pktlen; 2230 l = 0; /* in any case exit inner loop */ 2231 ip_off = ntohs(ip->ip_off); 2232 2233 /* if not fragmented, go to next rule */ 2234 if ((ip_off & (IP_MF | IP_OFFMASK)) == 0) 2235 break; 2236 /* 2237 * ip_reass() expects len & off in host 2238 * byte order. 2239 */ 2240 SET_HOST_IPLEN(ip); 2241 2242 args->m = m = ip_reass(m); 2243 2244 /* 2245 * do IP header checksum fixup. 2246 */ 2247 if (m == NULL) { /* fragment got swallowed */ 2248 retval = IP_FW_DENY; 2249 } else { /* good, packet complete */ 2250 int hlen; 2251 2252 ip = mtod(m, struct ip *); 2253 hlen = ip->ip_hl << 2; 2254 SET_NET_IPLEN(ip); 2255 ip->ip_sum = 0; 2256 if (hlen == sizeof(struct ip)) 2257 ip->ip_sum = in_cksum_hdr(ip); 2258 else 2259 ip->ip_sum = in_cksum(m, hlen); 2260 retval = IP_FW_REASS; 2261 set_match(args, f_pos, chain); 2262 } 2263 done = 1; /* exit outer loop */ 2264 break; 2265 } 2266 2267 default: 2268 panic("-- unknown opcode %d\n", cmd->opcode); 2269 } /* end of switch() on opcodes */ 2270 /* 2271 * if we get here with l=0, then match is irrelevant. 2272 */ 2273 2274 if (cmd->len & F_NOT) 2275 match = !match; 2276 2277 if (match) { 2278 if (cmd->len & F_OR) 2279 skip_or = 1; 2280 } else { 2281 if (!(cmd->len & F_OR)) /* not an OR block, */ 2282 break; /* try next rule */ 2283 } 2284 2285 } /* end of inner loop, scan opcodes */ 2286#undef PULLUP_LEN 2287 2288 if (done) 2289 break; 2290 2291/* next_rule:; */ /* try next rule */ 2292 2293 } /* end of outer for, scan rules */ 2294 2295 if (done) { 2296 struct ip_fw *rule = chain->map[f_pos]; 2297 /* Update statistics */ 2298 rule->pcnt++; 2299 rule->bcnt += pktlen; 2300 rule->timestamp = time_uptime; 2301 } else { 2302 retval = IP_FW_DENY; 2303 printf("ipfw: ouch!, skip past end of rules, denying packet\n"); 2304 } 2305 IPFW_RUNLOCK(chain); 2306#ifdef __FreeBSD__ 2307 if (ucred_cache != NULL) 2308 crfree(ucred_cache); 2309#endif 2310 return (retval); 2311 2312pullup_failed: 2313 if (V_fw_verbose) 2314 printf("ipfw: pullup failed\n"); 2315 return (IP_FW_DENY); 2316} 2317 2318/* 2319 * Module and VNET glue 2320 */ 2321 2322/* 2323 * Stuff that must be initialised only on boot or module load 2324 */ 2325static int 2326ipfw_init(void) 2327{ 2328 int error = 0; 2329 2330 ipfw_dyn_attach(); 2331 /* 2332 * Only print out this stuff the first time around, 2333 * when called from the sysinit code. 2334 */ 2335 printf("ipfw2 " 2336#ifdef INET6 2337 "(+ipv6) " 2338#endif 2339 "initialized, divert %s, nat %s, " 2340 "rule-based forwarding " 2341#ifdef IPFIREWALL_FORWARD 2342 "enabled, " 2343#else 2344 "disabled, " 2345#endif 2346 "default to %s, logging ", 2347#ifdef IPDIVERT 2348 "enabled", 2349#else 2350 "loadable", 2351#endif 2352#ifdef IPFIREWALL_NAT 2353 "enabled", 2354#else 2355 "loadable", 2356#endif 2357 default_to_accept ? "accept" : "deny"); 2358 2359 /* 2360 * Note: V_xxx variables can be accessed here but the vnet specific 2361 * initializer may not have been called yet for the VIMAGE case. 2362 * Tuneables will have been processed. We will print out values for 2363 * the default vnet. 2364 * XXX This should all be rationalized AFTER 8.0 2365 */ 2366 if (V_fw_verbose == 0) 2367 printf("disabled\n"); 2368 else if (V_verbose_limit == 0) 2369 printf("unlimited\n"); 2370 else 2371 printf("limited to %d packets/entry by default\n", 2372 V_verbose_limit); 2373 2374 ipfw_log_bpf(1); /* init */ 2375 return (error); 2376} 2377 2378/* 2379 * Called for the removal of the last instance only on module unload. 2380 */ 2381static void 2382ipfw_destroy(void) 2383{ 2384 2385 ipfw_log_bpf(0); /* uninit */ 2386 ipfw_dyn_detach(); 2387 printf("IP firewall unloaded\n"); 2388} 2389 2390/* 2391 * Stuff that must be initialized for every instance 2392 * (including the first of course). 2393 */ 2394static int 2395vnet_ipfw_init(const void *unused) 2396{ 2397 int error; 2398 struct ip_fw *rule = NULL; 2399 struct ip_fw_chain *chain; 2400 2401 chain = &V_layer3_chain; 2402 2403 /* First set up some values that are compile time options */ 2404 V_autoinc_step = 100; /* bounded to 1..1000 in add_rule() */ 2405 V_fw_deny_unknown_exthdrs = 1; 2406#ifdef IPFIREWALL_VERBOSE 2407 V_fw_verbose = 1; 2408#endif 2409#ifdef IPFIREWALL_VERBOSE_LIMIT 2410 V_verbose_limit = IPFIREWALL_VERBOSE_LIMIT; 2411#endif 2412#ifdef IPFIREWALL_NAT 2413 LIST_INIT(&chain->nat); 2414#endif 2415 2416 /* insert the default rule and create the initial map */ 2417 chain->n_rules = 1; 2418 chain->static_len = sizeof(struct ip_fw); 2419 chain->map = malloc(sizeof(struct ip_fw *), M_IPFW, M_NOWAIT | M_ZERO); 2420 if (chain->map) 2421 rule = malloc(chain->static_len, M_IPFW, M_NOWAIT | M_ZERO); 2422 if (rule == NULL) { 2423 if (chain->map) 2424 free(chain->map, M_IPFW); 2425 printf("ipfw2: ENOSPC initializing default rule " 2426 "(support disabled)\n"); 2427 return (ENOSPC); 2428 } 2429 error = ipfw_init_tables(chain); 2430 if (error) { 2431 panic("init_tables"); /* XXX Marko fix this ! */ 2432 } 2433 2434 /* fill and insert the default rule */ 2435 rule->act_ofs = 0; 2436 rule->rulenum = IPFW_DEFAULT_RULE; 2437 rule->cmd_len = 1; 2438 rule->set = RESVD_SET; 2439 rule->cmd[0].len = 1; 2440 rule->cmd[0].opcode = default_to_accept ? O_ACCEPT : O_DENY; 2441 chain->rules = chain->default_rule = chain->map[0] = rule; 2442 chain->id = rule->id = 1; 2443 2444 IPFW_LOCK_INIT(chain); 2445 ipfw_dyn_init(); 2446 2447 /* First set up some values that are compile time options */ 2448 V_ipfw_vnet_ready = 1; /* Open for business */ 2449 2450 /* 2451 * Hook the sockopt handler, and the layer2 (V_ip_fw_chk_ptr) 2452 * and pfil hooks for ipv4 and ipv6. Even if the latter two fail 2453 * we still keep the module alive because the sockopt and 2454 * layer2 paths are still useful. 2455 * ipfw[6]_hook return 0 on success, ENOENT on failure, 2456 * so we can ignore the exact return value and just set a flag. 2457 * 2458 * Note that V_fw[6]_enable are manipulated by a SYSCTL_PROC so 2459 * changes in the underlying (per-vnet) variables trigger 2460 * immediate hook()/unhook() calls. 2461 * In layer2 we have the same behaviour, except that V_ether_ipfw 2462 * is checked on each packet because there are no pfil hooks. 2463 */ 2464 V_ip_fw_ctl_ptr = ipfw_ctl; 2465 V_ip_fw_chk_ptr = ipfw_chk; 2466 error = ipfw_attach_hooks(1); 2467 return (error); 2468} 2469 2470/* 2471 * Called for the removal of each instance. 2472 */ 2473static int 2474vnet_ipfw_uninit(const void *unused) 2475{ 2476 struct ip_fw *reap, *rule; 2477 struct ip_fw_chain *chain = &V_layer3_chain; 2478 int i; 2479 2480 V_ipfw_vnet_ready = 0; /* tell new callers to go away */ 2481 /* 2482 * disconnect from ipv4, ipv6, layer2 and sockopt. 2483 * Then grab, release and grab again the WLOCK so we make 2484 * sure the update is propagated and nobody will be in. 2485 */ 2486 (void)ipfw_attach_hooks(0 /* detach */); 2487 V_ip_fw_chk_ptr = NULL; 2488 V_ip_fw_ctl_ptr = NULL; 2489 IPFW_UH_WLOCK(chain); 2490 IPFW_UH_WUNLOCK(chain); 2491 IPFW_UH_WLOCK(chain); 2492 2493 IPFW_WLOCK(chain); 2494 IPFW_WUNLOCK(chain); 2495 IPFW_WLOCK(chain); 2496 2497 ipfw_dyn_uninit(0); /* run the callout_drain */ 2498 ipfw_destroy_tables(chain); 2499 reap = NULL; 2500 for (i = 0; i < chain->n_rules; i++) { 2501 rule = chain->map[i]; 2502 rule->x_next = reap; 2503 reap = rule; 2504 } 2505 if (chain->map) 2506 free(chain->map, M_IPFW); 2507 IPFW_WUNLOCK(chain); 2508 IPFW_UH_WUNLOCK(chain); 2509 if (reap != NULL) 2510 ipfw_reap_rules(reap); 2511 IPFW_LOCK_DESTROY(chain); 2512 ipfw_dyn_uninit(1); /* free the remaining parts */ 2513 return 0; 2514} 2515 2516/* 2517 * Module event handler. 2518 * In general we have the choice of handling most of these events by the 2519 * event handler or by the (VNET_)SYS(UN)INIT handlers. I have chosen to 2520 * use the SYSINIT handlers as they are more capable of expressing the 2521 * flow of control during module and vnet operations, so this is just 2522 * a skeleton. Note there is no SYSINIT equivalent of the module 2523 * SHUTDOWN handler, but we don't have anything to do in that case anyhow. 2524 */ 2525static int 2526ipfw_modevent(module_t mod, int type, void *unused) 2527{ 2528 int err = 0; 2529 2530 switch (type) { 2531 case MOD_LOAD: 2532 /* Called once at module load or 2533 * system boot if compiled in. */ 2534 break; 2535 case MOD_QUIESCE: 2536 /* Called before unload. May veto unloading. */ 2537 break; 2538 case MOD_UNLOAD: 2539 /* Called during unload. */ 2540 break; 2541 case MOD_SHUTDOWN: 2542 /* Called during system shutdown. */ 2543 break; 2544 default: 2545 err = EOPNOTSUPP; 2546 break; 2547 } 2548 return err; 2549} 2550 2551static moduledata_t ipfwmod = { 2552 "ipfw", 2553 ipfw_modevent, 2554 0 2555}; 2556 2557/* Define startup order. */ 2558#define IPFW_SI_SUB_FIREWALL SI_SUB_PROTO_IFATTACHDOMAIN 2559#define IPFW_MODEVENT_ORDER (SI_ORDER_ANY - 255) /* On boot slot in here. */ 2560#define IPFW_MODULE_ORDER (IPFW_MODEVENT_ORDER + 1) /* A little later. */ 2561#define IPFW_VNET_ORDER (IPFW_MODEVENT_ORDER + 2) /* Later still. */ 2562 2563DECLARE_MODULE(ipfw, ipfwmod, IPFW_SI_SUB_FIREWALL, IPFW_MODEVENT_ORDER); 2564MODULE_VERSION(ipfw, 2); 2565/* should declare some dependencies here */ 2566 2567/* 2568 * Starting up. Done in order after ipfwmod() has been called. 2569 * VNET_SYSINIT is also called for each existing vnet and each new vnet. 2570 */ 2571SYSINIT(ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 2572 ipfw_init, NULL); 2573VNET_SYSINIT(vnet_ipfw_init, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 2574 vnet_ipfw_init, NULL); 2575 2576/* 2577 * Closing up shop. These are done in REVERSE ORDER, but still 2578 * after ipfwmod() has been called. Not called on reboot. 2579 * VNET_SYSUNINIT is also called for each exiting vnet as it exits. 2580 * or when the module is unloaded. 2581 */ 2582SYSUNINIT(ipfw_destroy, IPFW_SI_SUB_FIREWALL, IPFW_MODULE_ORDER, 2583 ipfw_destroy, NULL); 2584VNET_SYSUNINIT(vnet_ipfw_uninit, IPFW_SI_SUB_FIREWALL, IPFW_VNET_ORDER, 2585 vnet_ipfw_uninit, NULL); 2586/* end of file */ 2587