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 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #define DEB(x) 30 #define DDB(x) x 31 32 /* 33 * Dynamic rule support for ipfw 34 */ 35 36 #include "opt_ipfw.h" 37 #include "opt_inet.h" 38 #ifndef INET 39 #error IPFIREWALL requires INET. 40 #endif /* INET */ 41 #include "opt_inet6.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #include <sys/kernel.h> 48 #include <sys/ktr.h> 49 #include <sys/lock.h> 50 #include <sys/rmlock.h> 51 #include <sys/socket.h> 52 #include <sys/sysctl.h> 53 #include <sys/syslog.h> 54 #include <net/ethernet.h> /* for ETHERTYPE_IP */ 55 #include <net/if.h> 56 #include <net/if_var.h> 57 #include <net/vnet.h> 58 59 #include <netinet/in.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_var.h> /* ip_defttl */ 62 #include <netinet/ip_fw.h> 63 #include <netinet/tcp_var.h> 64 #include <netinet/udp.h> 65 66 #include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */ 67 #ifdef INET6 68 #include <netinet6/in6_var.h> 69 #include <netinet6/ip6_var.h> 70 #endif 71 72 #include <netpfil/ipfw/ip_fw_private.h> 73 74 #include <machine/in_cksum.h> /* XXX for in_cksum */ 75 76 #ifdef MAC 77 #include <security/mac/mac_framework.h> 78 #endif 79 80 /* 81 * Description of dynamic rules. 82 * 83 * Dynamic rules are stored in lists accessed through a hash table 84 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 85 * be modified through the sysctl variable dyn_buckets which is 86 * updated when the table becomes empty. 87 * 88 * XXX currently there is only one list, ipfw_dyn. 89 * 90 * When a packet is received, its address fields are first masked 91 * with the mask defined for the rule, then hashed, then matched 92 * against the entries in the corresponding list. 93 * Dynamic rules can be used for different purposes: 94 * + stateful rules; 95 * + enforcing limits on the number of sessions; 96 * + in-kernel NAT (not implemented yet) 97 * 98 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 99 * measured in seconds and depending on the flags. 100 * 101 * The total number of dynamic rules is equal to UMA zone items count. 102 * The max number of dynamic rules is dyn_max. When we reach 103 * the maximum number of rules we do not create anymore. This is 104 * done to avoid consuming too much memory, but also too much 105 * time when searching on each packet (ideally, we should try instead 106 * to put a limit on the length of the list on each bucket...). 107 * 108 * Each dynamic rule holds a pointer to the parent ipfw rule so 109 * we know what action to perform. Dynamic rules are removed when 110 * the parent rule is deleted. This can be changed by dyn_keep_states 111 * sysctl. 112 * 113 * There are some limitations with dynamic rules -- we do not 114 * obey the 'randomized match', and we do not do multiple 115 * passes through the firewall. XXX check the latter!!! 116 */ 117 118 struct ipfw_dyn_bucket { 119 struct mtx mtx; /* Bucket protecting lock */ 120 ipfw_dyn_rule *head; /* Pointer to first rule */ 121 }; 122 123 /* 124 * Static variables followed by global ones 125 */ 126 static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v); 127 static VNET_DEFINE(u_int32_t, dyn_buckets_max); 128 static VNET_DEFINE(u_int32_t, curr_dyn_buckets); 129 static VNET_DEFINE(struct callout, ipfw_timeout); 130 #define V_ipfw_dyn_v VNET(ipfw_dyn_v) 131 #define V_dyn_buckets_max VNET(dyn_buckets_max) 132 #define V_curr_dyn_buckets VNET(curr_dyn_buckets) 133 #define V_ipfw_timeout VNET(ipfw_timeout) 134 135 static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone); 136 #define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone) 137 138 #define IPFW_BUCK_LOCK_INIT(b) \ 139 mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF) 140 #define IPFW_BUCK_LOCK_DESTROY(b) \ 141 mtx_destroy(&(b)->mtx) 142 #define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx) 143 #define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx) 144 #define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED) 145 146 147 static VNET_DEFINE(int, dyn_keep_states); 148 #define V_dyn_keep_states VNET(dyn_keep_states) 149 150 /* 151 * Timeouts for various events in handing dynamic rules. 152 */ 153 static VNET_DEFINE(u_int32_t, dyn_ack_lifetime); 154 static VNET_DEFINE(u_int32_t, dyn_syn_lifetime); 155 static VNET_DEFINE(u_int32_t, dyn_fin_lifetime); 156 static VNET_DEFINE(u_int32_t, dyn_rst_lifetime); 157 static VNET_DEFINE(u_int32_t, dyn_udp_lifetime); 158 static VNET_DEFINE(u_int32_t, dyn_short_lifetime); 159 160 #define V_dyn_ack_lifetime VNET(dyn_ack_lifetime) 161 #define V_dyn_syn_lifetime VNET(dyn_syn_lifetime) 162 #define V_dyn_fin_lifetime VNET(dyn_fin_lifetime) 163 #define V_dyn_rst_lifetime VNET(dyn_rst_lifetime) 164 #define V_dyn_udp_lifetime VNET(dyn_udp_lifetime) 165 #define V_dyn_short_lifetime VNET(dyn_short_lifetime) 166 167 /* 168 * Keepalives are sent if dyn_keepalive is set. They are sent every 169 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 170 * seconds of lifetime of a rule. 171 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 172 * than dyn_keepalive_period. 173 */ 174 175 static VNET_DEFINE(u_int32_t, dyn_keepalive_interval); 176 static VNET_DEFINE(u_int32_t, dyn_keepalive_period); 177 static VNET_DEFINE(u_int32_t, dyn_keepalive); 178 static VNET_DEFINE(time_t, dyn_keepalive_last); 179 180 #define V_dyn_keepalive_interval VNET(dyn_keepalive_interval) 181 #define V_dyn_keepalive_period VNET(dyn_keepalive_period) 182 #define V_dyn_keepalive VNET(dyn_keepalive) 183 #define V_dyn_keepalive_last VNET(dyn_keepalive_last) 184 185 static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */ 186 187 #define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone) 188 #define V_dyn_max VNET(dyn_max) 189 190 /* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */ 191 static int ipfw_dyn_count; /* number of objects */ 192 193 #ifdef USERSPACE /* emulation of UMA object counters for userspace */ 194 #define uma_zone_get_cur(x) ipfw_dyn_count 195 #endif /* USERSPACE */ 196 197 static int last_log; /* Log ratelimiting */ 198 199 static void ipfw_dyn_tick(void *vnetx); 200 static void check_dyn_rules(struct ip_fw_chain *, ipfw_range_tlv *, int, int); 201 #ifdef SYSCTL_NODE 202 203 static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS); 204 static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS); 205 206 SYSBEGIN(f2) 207 208 SYSCTL_DECL(_net_inet_ip_fw); 209 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, 210 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0, 211 "Max number of dyn. buckets"); 212 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, 213 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0, 214 "Current Number of dyn. buckets"); 215 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count, 216 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU", 217 "Number of dyn. rules"); 218 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max, 219 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU", 220 "Max number of dyn. rules"); 221 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, 222 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0, 223 "Lifetime of dyn. rules for acks"); 224 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, 225 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0, 226 "Lifetime of dyn. rules for syn"); 227 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, 228 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0, 229 "Lifetime of dyn. rules for fin"); 230 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, 231 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0, 232 "Lifetime of dyn. rules for rst"); 233 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, 234 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0, 235 "Lifetime of dyn. rules for UDP"); 236 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, 237 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0, 238 "Lifetime of dyn. rules for other situations"); 239 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, 240 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0, 241 "Enable keepalives for dyn. rules"); 242 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states, 243 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0, 244 "Do not flush dynamic states on rule deletion"); 245 246 SYSEND 247 248 #endif /* SYSCTL_NODE */ 249 250 251 #ifdef INET6 252 static __inline int 253 hash_packet6(struct ipfw_flow_id *id) 254 { 255 u_int32_t i; 256 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 257 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 258 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 259 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^ 260 (id->dst_port) ^ (id->src_port); 261 return i; 262 } 263 #endif 264 265 /* 266 * IMPORTANT: the hash function for dynamic rules must be commutative 267 * in source and destination (ip,port), because rules are bidirectional 268 * and we want to find both in the same bucket. 269 */ 270 static __inline int 271 hash_packet(struct ipfw_flow_id *id, int buckets) 272 { 273 u_int32_t i; 274 275 #ifdef INET6 276 if (IS_IP6_FLOW_ID(id)) 277 i = hash_packet6(id); 278 else 279 #endif /* INET6 */ 280 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 281 i &= (buckets - 1); 282 return i; 283 } 284 285 /** 286 * Print customizable flow id description via log(9) facility. 287 */ 288 static void 289 print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags, 290 char *prefix, char *postfix) 291 { 292 struct in_addr da; 293 #ifdef INET6 294 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 295 #else 296 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 297 #endif 298 299 #ifdef INET6 300 if (IS_IP6_FLOW_ID(id)) { 301 ip6_sprintf(src, &id->src_ip6); 302 ip6_sprintf(dst, &id->dst_ip6); 303 } else 304 #endif 305 { 306 da.s_addr = htonl(id->src_ip); 307 inet_ntop(AF_INET, &da, src, sizeof(src)); 308 da.s_addr = htonl(id->dst_ip); 309 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 310 } 311 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 312 prefix, dyn_type, src, id->src_port, dst, 313 id->dst_port, DYN_COUNT, postfix); 314 } 315 316 #define print_dyn_rule(id, dtype, prefix, postfix) \ 317 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 318 319 #define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 320 #define TIME_LE(a,b) ((int)((a)-(b)) < 0) 321 322 static void 323 dyn_update_proto_state(ipfw_dyn_rule *q, const struct ipfw_flow_id *id, 324 const struct tcphdr *tcp, int dir) 325 { 326 uint32_t ack; 327 u_char flags; 328 329 if (id->proto == IPPROTO_TCP) { 330 flags = id->_flags & (TH_FIN | TH_SYN | TH_RST); 331 #define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 332 #define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 333 #define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 334 #define ACK_FWD 0x10000 /* fwd ack seen */ 335 #define ACK_REV 0x20000 /* rev ack seen */ 336 337 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 338 switch (q->state & TCP_FLAGS) { 339 case TH_SYN: /* opening */ 340 q->expire = time_uptime + V_dyn_syn_lifetime; 341 break; 342 343 case BOTH_SYN: /* move to established */ 344 case BOTH_SYN | TH_FIN: /* one side tries to close */ 345 case BOTH_SYN | (TH_FIN << 8): 346 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 347 if (tcp == NULL) 348 break; 349 350 ack = ntohl(tcp->th_ack); 351 if (dir == MATCH_FORWARD) { 352 if (q->ack_fwd == 0 || 353 _SEQ_GE(ack, q->ack_fwd)) { 354 q->ack_fwd = ack; 355 q->state |= ACK_FWD; 356 } 357 } else { 358 if (q->ack_rev == 0 || 359 _SEQ_GE(ack, q->ack_rev)) { 360 q->ack_rev = ack; 361 q->state |= ACK_REV; 362 } 363 } 364 if ((q->state & (ACK_FWD | ACK_REV)) == 365 (ACK_FWD | ACK_REV)) { 366 q->expire = time_uptime + V_dyn_ack_lifetime; 367 q->state &= ~(ACK_FWD | ACK_REV); 368 } 369 break; 370 371 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 372 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 373 V_dyn_fin_lifetime = 374 V_dyn_keepalive_period - 1; 375 q->expire = time_uptime + V_dyn_fin_lifetime; 376 break; 377 378 default: 379 #if 0 380 /* 381 * reset or some invalid combination, but can also 382 * occur if we use keep-state the wrong way. 383 */ 384 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 385 printf("invalid state: 0x%x\n", q->state); 386 #endif 387 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 388 V_dyn_rst_lifetime = 389 V_dyn_keepalive_period - 1; 390 q->expire = time_uptime + V_dyn_rst_lifetime; 391 break; 392 } 393 } else if (id->proto == IPPROTO_UDP) { 394 q->expire = time_uptime + V_dyn_udp_lifetime; 395 } else { 396 /* other protocols */ 397 q->expire = time_uptime + V_dyn_short_lifetime; 398 } 399 } 400 401 /* 402 * Lookup a dynamic rule, locked version. 403 */ 404 static ipfw_dyn_rule * 405 lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction, 406 struct tcphdr *tcp) 407 { 408 /* 409 * Stateful ipfw extensions. 410 * Lookup into dynamic session queue. 411 */ 412 ipfw_dyn_rule *prev, *q = NULL; 413 int dir; 414 415 IPFW_BUCK_ASSERT(i); 416 417 dir = MATCH_NONE; 418 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 419 if (q->dyn_type == O_LIMIT_PARENT && q->count) 420 continue; 421 422 if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT) 423 continue; 424 425 if (IS_IP6_FLOW_ID(pkt)) { 426 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 427 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 428 pkt->src_port == q->id.src_port && 429 pkt->dst_port == q->id.dst_port) { 430 dir = MATCH_FORWARD; 431 break; 432 } 433 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 434 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 435 pkt->src_port == q->id.dst_port && 436 pkt->dst_port == q->id.src_port) { 437 dir = MATCH_REVERSE; 438 break; 439 } 440 } else { 441 if (pkt->src_ip == q->id.src_ip && 442 pkt->dst_ip == q->id.dst_ip && 443 pkt->src_port == q->id.src_port && 444 pkt->dst_port == q->id.dst_port) { 445 dir = MATCH_FORWARD; 446 break; 447 } 448 if (pkt->src_ip == q->id.dst_ip && 449 pkt->dst_ip == q->id.src_ip && 450 pkt->src_port == q->id.dst_port && 451 pkt->dst_port == q->id.src_port) { 452 dir = MATCH_REVERSE; 453 break; 454 } 455 } 456 } 457 if (q == NULL) 458 goto done; /* q = NULL, not found */ 459 460 if (prev != NULL) { /* found and not in front */ 461 prev->next = q->next; 462 q->next = V_ipfw_dyn_v[i].head; 463 V_ipfw_dyn_v[i].head = q; 464 } 465 466 /* update state according to flags */ 467 dyn_update_proto_state(q, pkt, tcp, dir); 468 done: 469 if (match_direction != NULL) 470 *match_direction = dir; 471 return (q); 472 } 473 474 ipfw_dyn_rule * 475 ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 476 struct tcphdr *tcp) 477 { 478 ipfw_dyn_rule *q; 479 int i; 480 481 i = hash_packet(pkt, V_curr_dyn_buckets); 482 483 IPFW_BUCK_LOCK(i); 484 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp); 485 if (q == NULL) 486 IPFW_BUCK_UNLOCK(i); 487 /* NB: return table locked when q is not NULL */ 488 return q; 489 } 490 491 /* 492 * Unlock bucket mtx 493 * @p - pointer to dynamic rule 494 */ 495 void 496 ipfw_dyn_unlock(ipfw_dyn_rule *q) 497 { 498 499 IPFW_BUCK_UNLOCK(q->bucket); 500 } 501 502 static int 503 resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 504 { 505 int i, k, nbuckets_old; 506 ipfw_dyn_rule *q; 507 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 508 509 /* Check if given number is power of 2 and less than 64k */ 510 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 511 return 1; 512 513 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 514 V_curr_dyn_buckets, nbuckets); 515 516 /* Allocate and initialize new hash */ 517 dyn_v = malloc(nbuckets * sizeof(*dyn_v), M_IPFW, 518 M_WAITOK | M_ZERO); 519 520 for (i = 0 ; i < nbuckets; i++) 521 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 522 523 /* 524 * Call upper half lock, as get_map() do to ease 525 * read-only access to dynamic rules hash from sysctl 526 */ 527 IPFW_UH_WLOCK(chain); 528 529 /* 530 * Acquire chain write lock to permit hash access 531 * for main traffic path without additional locks 532 */ 533 IPFW_WLOCK(chain); 534 535 /* Save old values */ 536 nbuckets_old = V_curr_dyn_buckets; 537 dyn_v_old = V_ipfw_dyn_v; 538 539 /* Skip relinking if array is not set up */ 540 if (V_ipfw_dyn_v == NULL) 541 V_curr_dyn_buckets = 0; 542 543 /* Re-link all dynamic states */ 544 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 545 while (V_ipfw_dyn_v[i].head != NULL) { 546 /* Remove from current chain */ 547 q = V_ipfw_dyn_v[i].head; 548 V_ipfw_dyn_v[i].head = q->next; 549 550 /* Get new hash value */ 551 k = hash_packet(&q->id, nbuckets); 552 q->bucket = k; 553 /* Add to the new head */ 554 q->next = dyn_v[k].head; 555 dyn_v[k].head = q; 556 } 557 } 558 559 /* Update current pointers/buckets values */ 560 V_curr_dyn_buckets = nbuckets; 561 V_ipfw_dyn_v = dyn_v; 562 563 IPFW_WUNLOCK(chain); 564 565 IPFW_UH_WUNLOCK(chain); 566 567 /* Start periodic callout on initial creation */ 568 if (dyn_v_old == NULL) { 569 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 570 return (0); 571 } 572 573 /* Destroy all mutexes */ 574 for (i = 0 ; i < nbuckets_old ; i++) 575 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 576 577 /* Free old hash */ 578 free(dyn_v_old, M_IPFW); 579 580 return 0; 581 } 582 583 /** 584 * Install state of type 'type' for a dynamic session. 585 * The hash table contains two type of rules: 586 * - regular rules (O_KEEP_STATE) 587 * - rules for sessions with limited number of sess per user 588 * (O_LIMIT). When they are created, the parent is 589 * increased by 1, and decreased on delete. In this case, 590 * the third parameter is the parent rule and not the chain. 591 * - "parent" rules for the above (O_LIMIT_PARENT). 592 */ 593 static ipfw_dyn_rule * 594 add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule) 595 { 596 ipfw_dyn_rule *r; 597 598 IPFW_BUCK_ASSERT(i); 599 600 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 601 if (r == NULL) { 602 if (last_log != time_uptime) { 603 last_log = time_uptime; 604 log(LOG_DEBUG, 605 "ipfw: Cannot allocate dynamic state, " 606 "consider increasing net.inet.ip.fw.dyn_max\n"); 607 } 608 return NULL; 609 } 610 ipfw_dyn_count++; 611 612 /* 613 * refcount on parent is already incremented, so 614 * it is safe to use parent unlocked. 615 */ 616 if (dyn_type == O_LIMIT) { 617 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 618 if ( parent->dyn_type != O_LIMIT_PARENT) 619 panic("invalid parent"); 620 r->parent = parent; 621 rule = parent->rule; 622 } 623 624 r->id = *id; 625 r->expire = time_uptime + V_dyn_syn_lifetime; 626 r->rule = rule; 627 r->dyn_type = dyn_type; 628 IPFW_ZERO_DYN_COUNTER(r); 629 r->count = 0; 630 631 r->bucket = i; 632 r->next = V_ipfw_dyn_v[i].head; 633 V_ipfw_dyn_v[i].head = r; 634 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 635 return r; 636 } 637 638 /** 639 * lookup dynamic parent rule using pkt and rule as search keys. 640 * If the lookup fails, then install one. 641 */ 642 static ipfw_dyn_rule * 643 lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule) 644 { 645 ipfw_dyn_rule *q; 646 int i, is_v6; 647 648 is_v6 = IS_IP6_FLOW_ID(pkt); 649 i = hash_packet( pkt, V_curr_dyn_buckets ); 650 *pindex = i; 651 IPFW_BUCK_LOCK(i); 652 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 653 if (q->dyn_type == O_LIMIT_PARENT && 654 rule== q->rule && 655 pkt->proto == q->id.proto && 656 pkt->src_port == q->id.src_port && 657 pkt->dst_port == q->id.dst_port && 658 ( 659 (is_v6 && 660 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 661 &(q->id.src_ip6)) && 662 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 663 &(q->id.dst_ip6))) || 664 (!is_v6 && 665 pkt->src_ip == q->id.src_ip && 666 pkt->dst_ip == q->id.dst_ip) 667 ) 668 ) { 669 q->expire = time_uptime + V_dyn_short_lifetime; 670 DEB(print_dyn_rule(pkt, q->dyn_type, 671 "lookup_dyn_parent found", "");) 672 return q; 673 } 674 675 /* Add virtual limiting rule */ 676 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule); 677 } 678 679 /** 680 * Install dynamic state for rule type cmd->o.opcode 681 * 682 * Returns 1 (failure) if state is not installed because of errors or because 683 * session limitations are enforced. 684 */ 685 int 686 ipfw_install_state(struct ip_fw_chain *chain, struct ip_fw *rule, 687 ipfw_insn_limit *cmd, struct ip_fw_args *args, uint32_t tablearg) 688 { 689 ipfw_dyn_rule *q; 690 int i, dir; 691 692 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");) 693 694 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 695 696 IPFW_BUCK_LOCK(i); 697 698 q = lookup_dyn_rule_locked(&args->f_id, i, &dir, NULL); 699 if (q != NULL) { /* should never occur */ 700 DEB( 701 if (last_log != time_uptime) { 702 last_log = time_uptime; 703 printf("ipfw: %s: entry already present, done\n", 704 __func__); 705 }) 706 IPFW_BUCK_UNLOCK(i); 707 return (0); 708 } 709 710 /* 711 * State limiting is done via uma(9) zone limiting. 712 * Save pointer to newly-installed rule and reject 713 * packet if add_dyn_rule() returned NULL. 714 * Note q is currently set to NULL. 715 */ 716 717 switch (cmd->o.opcode) { 718 case O_KEEP_STATE: /* bidir rule */ 719 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule); 720 break; 721 722 case O_LIMIT: { /* limit number of sessions */ 723 struct ipfw_flow_id id; 724 ipfw_dyn_rule *parent; 725 uint32_t conn_limit; 726 uint16_t limit_mask = cmd->limit_mask; 727 int pindex; 728 729 conn_limit = IP_FW_ARG_TABLEARG(chain, cmd->conn_limit, limit); 730 731 DEB( 732 if (cmd->conn_limit == IP_FW_TARG) 733 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 734 "(tablearg)\n", __func__, conn_limit); 735 else 736 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 737 __func__, conn_limit); 738 ) 739 740 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 741 id.proto = args->f_id.proto; 742 id.addr_type = args->f_id.addr_type; 743 id.fib = M_GETFIB(args->m); 744 745 if (IS_IP6_FLOW_ID (&(args->f_id))) { 746 bzero(&id.src_ip6, sizeof(id.src_ip6)); 747 bzero(&id.dst_ip6, sizeof(id.dst_ip6)); 748 749 if (limit_mask & DYN_SRC_ADDR) 750 id.src_ip6 = args->f_id.src_ip6; 751 if (limit_mask & DYN_DST_ADDR) 752 id.dst_ip6 = args->f_id.dst_ip6; 753 } else { 754 if (limit_mask & DYN_SRC_ADDR) 755 id.src_ip = args->f_id.src_ip; 756 if (limit_mask & DYN_DST_ADDR) 757 id.dst_ip = args->f_id.dst_ip; 758 } 759 if (limit_mask & DYN_SRC_PORT) 760 id.src_port = args->f_id.src_port; 761 if (limit_mask & DYN_DST_PORT) 762 id.dst_port = args->f_id.dst_port; 763 764 /* 765 * We have to release lock for previous bucket to 766 * avoid possible deadlock 767 */ 768 IPFW_BUCK_UNLOCK(i); 769 770 if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) { 771 printf("ipfw: %s: add parent failed\n", __func__); 772 IPFW_BUCK_UNLOCK(pindex); 773 return (1); 774 } 775 776 if (parent->count >= conn_limit) { 777 if (V_fw_verbose && last_log != time_uptime) { 778 last_log = time_uptime; 779 char sbuf[24]; 780 last_log = time_uptime; 781 snprintf(sbuf, sizeof(sbuf), 782 "%d drop session", 783 parent->rule->rulenum); 784 print_dyn_rule_flags(&args->f_id, 785 cmd->o.opcode, 786 LOG_SECURITY | LOG_DEBUG, 787 sbuf, "too many entries"); 788 } 789 IPFW_BUCK_UNLOCK(pindex); 790 return (1); 791 } 792 /* Increment counter on parent */ 793 parent->count++; 794 IPFW_BUCK_UNLOCK(pindex); 795 796 IPFW_BUCK_LOCK(i); 797 q = add_dyn_rule(&args->f_id, i, O_LIMIT, 798 (struct ip_fw *)parent); 799 if (q == NULL) { 800 /* Decrement index and notify caller */ 801 IPFW_BUCK_UNLOCK(i); 802 IPFW_BUCK_LOCK(pindex); 803 parent->count--; 804 IPFW_BUCK_UNLOCK(pindex); 805 return (1); 806 } 807 break; 808 } 809 default: 810 printf("ipfw: %s: unknown dynamic rule type %u\n", 811 __func__, cmd->o.opcode); 812 } 813 814 if (q == NULL) { 815 IPFW_BUCK_UNLOCK(i); 816 return (1); /* Notify caller about failure */ 817 } 818 819 dyn_update_proto_state(q, &args->f_id, NULL, dir); 820 IPFW_BUCK_UNLOCK(i); 821 return (0); 822 } 823 824 /* 825 * Generate a TCP packet, containing either a RST or a keepalive. 826 * When flags & TH_RST, we are sending a RST packet, because of a 827 * "reset" action matched the packet. 828 * Otherwise we are sending a keepalive, and flags & TH_ 829 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 830 * so that MAC can label the reply appropriately. 831 */ 832 struct mbuf * 833 ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 834 u_int32_t ack, int flags) 835 { 836 struct mbuf *m = NULL; /* stupid compiler */ 837 int len, dir; 838 struct ip *h = NULL; /* stupid compiler */ 839 #ifdef INET6 840 struct ip6_hdr *h6 = NULL; 841 #endif 842 struct tcphdr *th = NULL; 843 844 MGETHDR(m, M_NOWAIT, MT_DATA); 845 if (m == NULL) 846 return (NULL); 847 848 M_SETFIB(m, id->fib); 849 #ifdef MAC 850 if (replyto != NULL) 851 mac_netinet_firewall_reply(replyto, m); 852 else 853 mac_netinet_firewall_send(m); 854 #else 855 (void)replyto; /* don't warn about unused arg */ 856 #endif 857 858 switch (id->addr_type) { 859 case 4: 860 len = sizeof(struct ip) + sizeof(struct tcphdr); 861 break; 862 #ifdef INET6 863 case 6: 864 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 865 break; 866 #endif 867 default: 868 /* XXX: log me?!? */ 869 FREE_PKT(m); 870 return (NULL); 871 } 872 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 873 874 m->m_data += max_linkhdr; 875 m->m_flags |= M_SKIP_FIREWALL; 876 m->m_pkthdr.len = m->m_len = len; 877 m->m_pkthdr.rcvif = NULL; 878 bzero(m->m_data, len); 879 880 switch (id->addr_type) { 881 case 4: 882 h = mtod(m, struct ip *); 883 884 /* prepare for checksum */ 885 h->ip_p = IPPROTO_TCP; 886 h->ip_len = htons(sizeof(struct tcphdr)); 887 if (dir) { 888 h->ip_src.s_addr = htonl(id->src_ip); 889 h->ip_dst.s_addr = htonl(id->dst_ip); 890 } else { 891 h->ip_src.s_addr = htonl(id->dst_ip); 892 h->ip_dst.s_addr = htonl(id->src_ip); 893 } 894 895 th = (struct tcphdr *)(h + 1); 896 break; 897 #ifdef INET6 898 case 6: 899 h6 = mtod(m, struct ip6_hdr *); 900 901 /* prepare for checksum */ 902 h6->ip6_nxt = IPPROTO_TCP; 903 h6->ip6_plen = htons(sizeof(struct tcphdr)); 904 if (dir) { 905 h6->ip6_src = id->src_ip6; 906 h6->ip6_dst = id->dst_ip6; 907 } else { 908 h6->ip6_src = id->dst_ip6; 909 h6->ip6_dst = id->src_ip6; 910 } 911 912 th = (struct tcphdr *)(h6 + 1); 913 break; 914 #endif 915 } 916 917 if (dir) { 918 th->th_sport = htons(id->src_port); 919 th->th_dport = htons(id->dst_port); 920 } else { 921 th->th_sport = htons(id->dst_port); 922 th->th_dport = htons(id->src_port); 923 } 924 th->th_off = sizeof(struct tcphdr) >> 2; 925 926 if (flags & TH_RST) { 927 if (flags & TH_ACK) { 928 th->th_seq = htonl(ack); 929 th->th_flags = TH_RST; 930 } else { 931 if (flags & TH_SYN) 932 seq++; 933 th->th_ack = htonl(seq); 934 th->th_flags = TH_RST | TH_ACK; 935 } 936 } else { 937 /* 938 * Keepalive - use caller provided sequence numbers 939 */ 940 th->th_seq = htonl(seq); 941 th->th_ack = htonl(ack); 942 th->th_flags = TH_ACK; 943 } 944 945 switch (id->addr_type) { 946 case 4: 947 th->th_sum = in_cksum(m, len); 948 949 /* finish the ip header */ 950 h->ip_v = 4; 951 h->ip_hl = sizeof(*h) >> 2; 952 h->ip_tos = IPTOS_LOWDELAY; 953 h->ip_off = htons(0); 954 h->ip_len = htons(len); 955 h->ip_ttl = V_ip_defttl; 956 h->ip_sum = 0; 957 break; 958 #ifdef INET6 959 case 6: 960 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 961 sizeof(struct tcphdr)); 962 963 /* finish the ip6 header */ 964 h6->ip6_vfc |= IPV6_VERSION; 965 h6->ip6_hlim = IPV6_DEFHLIM; 966 break; 967 #endif 968 } 969 970 return (m); 971 } 972 973 /* 974 * Queue keepalive packets for given dynamic rule 975 */ 976 static struct mbuf ** 977 ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 978 { 979 struct mbuf *m_rev, *m_fwd; 980 981 m_rev = (q->state & ACK_REV) ? NULL : 982 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 983 m_fwd = (q->state & ACK_FWD) ? NULL : 984 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 985 986 if (m_rev != NULL) { 987 *mtailp = m_rev; 988 mtailp = &(*mtailp)->m_nextpkt; 989 } 990 if (m_fwd != NULL) { 991 *mtailp = m_fwd; 992 mtailp = &(*mtailp)->m_nextpkt; 993 } 994 995 return (mtailp); 996 } 997 998 /* 999 * This procedure is used to perform various maintenance 1000 * on dynamic hash list. Currently it is called every second. 1001 */ 1002 static void 1003 ipfw_dyn_tick(void * vnetx) 1004 { 1005 struct ip_fw_chain *chain; 1006 int check_ka = 0; 1007 #ifdef VIMAGE 1008 struct vnet *vp = vnetx; 1009 #endif 1010 1011 CURVNET_SET(vp); 1012 1013 chain = &V_layer3_chain; 1014 1015 /* Run keepalive checks every keepalive_period iff ka is enabled */ 1016 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 1017 (V_dyn_keepalive != 0)) { 1018 V_dyn_keepalive_last = time_uptime; 1019 check_ka = 1; 1020 } 1021 1022 check_dyn_rules(chain, NULL, check_ka, 1); 1023 1024 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 1025 1026 CURVNET_RESTORE(); 1027 } 1028 1029 1030 /* 1031 * Walk through all dynamic states doing generic maintenance: 1032 * 1) free expired states 1033 * 2) free all states based on deleted rule / set 1034 * 3) send keepalives for states if needed 1035 * 1036 * @chain - pointer to current ipfw rules chain 1037 * @rule - delete all states originated by given rule if != NULL 1038 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1039 * @check_ka - perform checking/sending keepalives 1040 * @timer - indicate call from timer routine. 1041 * 1042 * Timer routine must call this function unlocked to permit 1043 * sending keepalives/resizing table. 1044 * 1045 * Others has to call function with IPFW_UH_WLOCK held. 1046 * Additionally, function assume that dynamic rule/set is 1047 * ALREADY deleted so no new states can be generated by 1048 * 'deleted' rules. 1049 * 1050 * Write lock is needed to ensure that unused parent rules 1051 * are not freed by other instance (see stage 2, 3) 1052 */ 1053 static void 1054 check_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt, 1055 int check_ka, int timer) 1056 { 1057 struct mbuf *m0, *m, *mnext, **mtailp; 1058 struct ip *h; 1059 int i, dyn_count, new_buckets = 0, max_buckets; 1060 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1061 ipfw_dyn_rule *q, *q_prev, *q_next; 1062 ipfw_dyn_rule *exp_head, **exptailp; 1063 ipfw_dyn_rule *exp_lhead, **expltailp; 1064 1065 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1066 __func__)); 1067 1068 /* Avoid possible LOR */ 1069 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1070 __func__)); 1071 1072 /* 1073 * Do not perform any checks if we currently have no dynamic states 1074 */ 1075 if (DYN_COUNT == 0) 1076 return; 1077 1078 /* Expired states */ 1079 exp_head = NULL; 1080 exptailp = &exp_head; 1081 1082 /* Expired limit states */ 1083 exp_lhead = NULL; 1084 expltailp = &exp_lhead; 1085 1086 /* 1087 * We make a chain of packets to go out here -- not deferring 1088 * until after we drop the IPFW dynamic rule lock would result 1089 * in a lock order reversal with the normal packet input -> ipfw 1090 * call stack. 1091 */ 1092 m0 = NULL; 1093 mtailp = &m0; 1094 1095 /* Protect from hash resizing */ 1096 if (timer != 0) 1097 IPFW_UH_WLOCK(chain); 1098 else 1099 IPFW_UH_WLOCK_ASSERT(chain); 1100 1101 #define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1102 1103 /* Stage 1: perform requested deletion */ 1104 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1105 IPFW_BUCK_LOCK(i); 1106 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1107 /* account every rule */ 1108 total++; 1109 1110 /* Skip parent rules at all */ 1111 if (q->dyn_type == O_LIMIT_PARENT) { 1112 parents++; 1113 NEXT_RULE(); 1114 } 1115 1116 /* 1117 * Remove rules which are: 1118 * 1) expired 1119 * 2) matches deletion range 1120 */ 1121 if ((TIME_LEQ(q->expire, time_uptime)) || 1122 (rt != NULL && ipfw_match_range(q->rule, rt))) { 1123 if (TIME_LE(time_uptime, q->expire) && 1124 q->dyn_type == O_KEEP_STATE && 1125 V_dyn_keep_states != 0) { 1126 /* 1127 * Do not delete state if 1128 * it is not expired and 1129 * dyn_keep_states is ON. 1130 * However we need to re-link it 1131 * to any other stable rule 1132 */ 1133 q->rule = chain->default_rule; 1134 NEXT_RULE(); 1135 } 1136 1137 /* Unlink q from current list */ 1138 q_next = q->next; 1139 if (q == V_ipfw_dyn_v[i].head) 1140 V_ipfw_dyn_v[i].head = q_next; 1141 else 1142 q_prev->next = q_next; 1143 1144 q->next = NULL; 1145 1146 /* queue q to expire list */ 1147 if (q->dyn_type != O_LIMIT) { 1148 *exptailp = q; 1149 exptailp = &(*exptailp)->next; 1150 DEB(print_dyn_rule(&q->id, q->dyn_type, 1151 "unlink entry", "left"); 1152 ) 1153 } else { 1154 /* Separate list for limit rules */ 1155 *expltailp = q; 1156 expltailp = &(*expltailp)->next; 1157 expired_limits++; 1158 DEB(print_dyn_rule(&q->id, q->dyn_type, 1159 "unlink limit entry", "left"); 1160 ) 1161 } 1162 1163 q = q_next; 1164 expired++; 1165 continue; 1166 } 1167 1168 /* 1169 * Check if we need to send keepalive: 1170 * we need to ensure if is time to do KA, 1171 * this is established TCP session, and 1172 * expire time is within keepalive interval 1173 */ 1174 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1175 ((q->state & BOTH_SYN) == BOTH_SYN) && 1176 (TIME_LEQ(q->expire, time_uptime + 1177 V_dyn_keepalive_interval))) 1178 mtailp = ipfw_dyn_send_ka(mtailp, q); 1179 1180 NEXT_RULE(); 1181 } 1182 IPFW_BUCK_UNLOCK(i); 1183 } 1184 1185 /* Stage 2: decrement counters from O_LIMIT parents */ 1186 if (expired_limits != 0) { 1187 /* 1188 * XXX: Note that deleting set with more than one 1189 * heavily-used LIMIT rules can result in overwhelming 1190 * locking due to lack of per-hash value sorting 1191 * 1192 * We should probably think about: 1193 * 1) pre-allocating hash of size, say, 1194 * MAX(16, V_curr_dyn_buckets / 1024) 1195 * 2) checking if expired_limits is large enough 1196 * 3) If yes, init hash (or its part), re-link 1197 * current list and start decrementing procedure in 1198 * each bucket separately 1199 */ 1200 1201 /* 1202 * Small optimization: do not unlock bucket until 1203 * we see the next item resides in different bucket 1204 */ 1205 if (exp_lhead != NULL) { 1206 i = exp_lhead->parent->bucket; 1207 IPFW_BUCK_LOCK(i); 1208 } 1209 for (q = exp_lhead; q != NULL; q = q->next) { 1210 if (i != q->parent->bucket) { 1211 IPFW_BUCK_UNLOCK(i); 1212 i = q->parent->bucket; 1213 IPFW_BUCK_LOCK(i); 1214 } 1215 1216 /* Decrease parent refcount */ 1217 q->parent->count--; 1218 } 1219 if (exp_lhead != NULL) 1220 IPFW_BUCK_UNLOCK(i); 1221 } 1222 1223 /* 1224 * We protectet ourselves from unused parent deletion 1225 * (from the timer function) by holding UH write lock. 1226 */ 1227 1228 /* Stage 3: remove unused parent rules */ 1229 if ((parents != 0) && (expired != 0)) { 1230 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1231 IPFW_BUCK_LOCK(i); 1232 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1233 if (q->dyn_type != O_LIMIT_PARENT) 1234 NEXT_RULE(); 1235 1236 if (q->count != 0) 1237 NEXT_RULE(); 1238 1239 /* Parent rule without consumers */ 1240 1241 /* Unlink q from current list */ 1242 q_next = q->next; 1243 if (q == V_ipfw_dyn_v[i].head) 1244 V_ipfw_dyn_v[i].head = q_next; 1245 else 1246 q_prev->next = q_next; 1247 1248 q->next = NULL; 1249 1250 /* Add to expired list */ 1251 *exptailp = q; 1252 exptailp = &(*exptailp)->next; 1253 1254 DEB(print_dyn_rule(&q->id, q->dyn_type, 1255 "unlink parent entry", "left"); 1256 ) 1257 1258 expired++; 1259 1260 q = q_next; 1261 } 1262 IPFW_BUCK_UNLOCK(i); 1263 } 1264 } 1265 1266 #undef NEXT_RULE 1267 1268 if (timer != 0) { 1269 /* 1270 * Check if we need to resize hash: 1271 * if current number of states exceeds number of buckes in hash, 1272 * grow hash size to the minimum power of 2 which is bigger than 1273 * current states count. Limit hash size by 64k. 1274 */ 1275 max_buckets = (V_dyn_buckets_max > 65536) ? 1276 65536 : V_dyn_buckets_max; 1277 1278 dyn_count = DYN_COUNT; 1279 1280 if ((dyn_count > V_curr_dyn_buckets * 2) && 1281 (dyn_count < max_buckets)) { 1282 new_buckets = V_curr_dyn_buckets; 1283 while (new_buckets < dyn_count) { 1284 new_buckets *= 2; 1285 1286 if (new_buckets >= max_buckets) 1287 break; 1288 } 1289 } 1290 1291 IPFW_UH_WUNLOCK(chain); 1292 } 1293 1294 /* Finally delete old states ad limits if any */ 1295 for (q = exp_head; q != NULL; q = q_next) { 1296 q_next = q->next; 1297 uma_zfree(V_ipfw_dyn_rule_zone, q); 1298 ipfw_dyn_count--; 1299 } 1300 1301 for (q = exp_lhead; q != NULL; q = q_next) { 1302 q_next = q->next; 1303 uma_zfree(V_ipfw_dyn_rule_zone, q); 1304 ipfw_dyn_count--; 1305 } 1306 1307 /* 1308 * The rest code MUST be called from timer routine only 1309 * without holding any locks 1310 */ 1311 if (timer == 0) 1312 return; 1313 1314 /* Send keepalive packets if any */ 1315 for (m = m0; m != NULL; m = mnext) { 1316 mnext = m->m_nextpkt; 1317 m->m_nextpkt = NULL; 1318 h = mtod(m, struct ip *); 1319 if (h->ip_v == 4) 1320 ip_output(m, NULL, NULL, 0, NULL, NULL); 1321 #ifdef INET6 1322 else 1323 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1324 #endif 1325 } 1326 1327 /* Run table resize without holding any locks */ 1328 if (new_buckets != 0) 1329 resize_dynamic_table(chain, new_buckets); 1330 } 1331 1332 /* 1333 * Deletes all dynamic rules originated by given rule or all rules in 1334 * given set. Specify RESVD_SET to indicate set should not be used. 1335 * @chain - pointer to current ipfw rules chain 1336 * @rr - delete all states originated by rules in matched range. 1337 * 1338 * Function has to be called with IPFW_UH_WLOCK held. 1339 * Additionally, function assume that dynamic rule/set is 1340 * ALREADY deleted so no new states can be generated by 1341 * 'deleted' rules. 1342 */ 1343 void 1344 ipfw_expire_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt) 1345 { 1346 1347 check_dyn_rules(chain, rt, 0, 0); 1348 } 1349 1350 /* 1351 * Check if rule contains at least one dynamic opcode. 1352 * 1353 * Returns 1 if such opcode is found, 0 otherwise. 1354 */ 1355 int 1356 ipfw_is_dyn_rule(struct ip_fw *rule) 1357 { 1358 int cmdlen, l; 1359 ipfw_insn *cmd; 1360 1361 l = rule->cmd_len; 1362 cmd = rule->cmd; 1363 cmdlen = 0; 1364 for ( ; l > 0 ; l -= cmdlen, cmd += cmdlen) { 1365 cmdlen = F_LEN(cmd); 1366 1367 switch (cmd->opcode) { 1368 case O_LIMIT: 1369 case O_KEEP_STATE: 1370 case O_PROBE_STATE: 1371 case O_CHECK_STATE: 1372 return (1); 1373 } 1374 } 1375 1376 return (0); 1377 } 1378 1379 void 1380 ipfw_dyn_init(struct ip_fw_chain *chain) 1381 { 1382 1383 V_ipfw_dyn_v = NULL; 1384 V_dyn_buckets_max = 256; /* must be power of 2 */ 1385 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1386 1387 V_dyn_ack_lifetime = 300; 1388 V_dyn_syn_lifetime = 20; 1389 V_dyn_fin_lifetime = 1; 1390 V_dyn_rst_lifetime = 1; 1391 V_dyn_udp_lifetime = 10; 1392 V_dyn_short_lifetime = 5; 1393 1394 V_dyn_keepalive_interval = 20; 1395 V_dyn_keepalive_period = 5; 1396 V_dyn_keepalive = 1; /* do send keepalives */ 1397 V_dyn_keepalive_last = time_uptime; 1398 1399 V_dyn_max = 16384; /* max # of dynamic rules */ 1400 1401 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1402 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1403 UMA_ALIGN_PTR, 0); 1404 1405 /* Enforce limit on dynamic rules */ 1406 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1407 1408 callout_init(&V_ipfw_timeout, 1); 1409 1410 /* 1411 * This can potentially be done on first dynamic rule 1412 * being added to chain. 1413 */ 1414 resize_dynamic_table(chain, V_curr_dyn_buckets); 1415 } 1416 1417 void 1418 ipfw_dyn_uninit(int pass) 1419 { 1420 int i; 1421 1422 if (pass == 0) { 1423 callout_drain(&V_ipfw_timeout); 1424 return; 1425 } 1426 1427 if (V_ipfw_dyn_v != NULL) { 1428 /* 1429 * Skip deleting all dynamic states - 1430 * uma_zdestroy() does this more efficiently; 1431 */ 1432 1433 /* Destroy all mutexes */ 1434 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1435 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1436 free(V_ipfw_dyn_v, M_IPFW); 1437 V_ipfw_dyn_v = NULL; 1438 } 1439 1440 uma_zdestroy(V_ipfw_dyn_rule_zone); 1441 } 1442 1443 #ifdef SYSCTL_NODE 1444 /* 1445 * Get/set maximum number of dynamic states in given VNET instance. 1446 */ 1447 static int 1448 sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1449 { 1450 int error; 1451 unsigned int nstates; 1452 1453 nstates = V_dyn_max; 1454 1455 error = sysctl_handle_int(oidp, &nstates, 0, req); 1456 /* Read operation or some error */ 1457 if ((error != 0) || (req->newptr == NULL)) 1458 return (error); 1459 1460 V_dyn_max = nstates; 1461 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1462 1463 return (0); 1464 } 1465 1466 /* 1467 * Get current number of dynamic states in given VNET instance. 1468 */ 1469 static int 1470 sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1471 { 1472 int error; 1473 unsigned int nstates; 1474 1475 nstates = DYN_COUNT; 1476 1477 error = sysctl_handle_int(oidp, &nstates, 0, req); 1478 1479 return (error); 1480 } 1481 #endif 1482 1483 /* 1484 * Returns size of dynamic states in legacy format 1485 */ 1486 int 1487 ipfw_dyn_len(void) 1488 { 1489 1490 return (V_ipfw_dyn_v == NULL) ? 0 : 1491 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1492 } 1493 1494 /* 1495 * Returns number of dynamic states. 1496 * Used by dump format v1 (current). 1497 */ 1498 int 1499 ipfw_dyn_get_count(void) 1500 { 1501 1502 return (V_ipfw_dyn_v == NULL) ? 0 : DYN_COUNT; 1503 } 1504 1505 static void 1506 export_dyn_rule(ipfw_dyn_rule *src, ipfw_dyn_rule *dst) 1507 { 1508 1509 memcpy(dst, src, sizeof(*src)); 1510 memcpy(&(dst->rule), &(src->rule->rulenum), sizeof(src->rule->rulenum)); 1511 /* 1512 * store set number into high word of 1513 * dst->rule pointer. 1514 */ 1515 memcpy((char *)&dst->rule + sizeof(src->rule->rulenum), 1516 &(src->rule->set), sizeof(src->rule->set)); 1517 /* 1518 * store a non-null value in "next". 1519 * The userland code will interpret a 1520 * NULL here as a marker 1521 * for the last dynamic rule. 1522 */ 1523 memcpy(&dst->next, &dst, sizeof(dst)); 1524 dst->expire = 1525 TIME_LEQ(dst->expire, time_uptime) ? 0 : dst->expire - time_uptime; 1526 } 1527 1528 /* 1529 * Fills int buffer given by @sd with dynamic states. 1530 * Used by dump format v1 (current). 1531 * 1532 * Returns 0 on success. 1533 */ 1534 int 1535 ipfw_dump_states(struct ip_fw_chain *chain, struct sockopt_data *sd) 1536 { 1537 ipfw_dyn_rule *p; 1538 ipfw_obj_dyntlv *dst, *last; 1539 ipfw_obj_ctlv *ctlv; 1540 int i; 1541 size_t sz; 1542 1543 if (V_ipfw_dyn_v == NULL) 1544 return (0); 1545 1546 IPFW_UH_RLOCK_ASSERT(chain); 1547 1548 ctlv = (ipfw_obj_ctlv *)ipfw_get_sopt_space(sd, sizeof(*ctlv)); 1549 if (ctlv == NULL) 1550 return (ENOMEM); 1551 sz = sizeof(ipfw_obj_dyntlv); 1552 ctlv->head.type = IPFW_TLV_DYNSTATE_LIST; 1553 ctlv->objsize = sz; 1554 last = NULL; 1555 1556 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1557 IPFW_BUCK_LOCK(i); 1558 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1559 dst = (ipfw_obj_dyntlv *)ipfw_get_sopt_space(sd, sz); 1560 if (dst == NULL) { 1561 IPFW_BUCK_UNLOCK(i); 1562 return (ENOMEM); 1563 } 1564 1565 export_dyn_rule(p, &dst->state); 1566 dst->head.length = sz; 1567 dst->head.type = IPFW_TLV_DYN_ENT; 1568 last = dst; 1569 } 1570 IPFW_BUCK_UNLOCK(i); 1571 } 1572 1573 if (last != NULL) /* mark last dynamic rule */ 1574 last->head.flags = IPFW_DF_LAST; 1575 1576 return (0); 1577 } 1578 1579 /* 1580 * Fill given buffer with dynamic states (legacy format). 1581 * IPFW_UH_RLOCK has to be held while calling. 1582 */ 1583 void 1584 ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1585 { 1586 ipfw_dyn_rule *p, *last = NULL; 1587 char *bp; 1588 int i; 1589 1590 if (V_ipfw_dyn_v == NULL) 1591 return; 1592 bp = *pbp; 1593 1594 IPFW_UH_RLOCK_ASSERT(chain); 1595 1596 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1597 IPFW_BUCK_LOCK(i); 1598 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1599 if (bp + sizeof *p <= ep) { 1600 ipfw_dyn_rule *dst = 1601 (ipfw_dyn_rule *)bp; 1602 1603 export_dyn_rule(p, dst); 1604 last = dst; 1605 bp += sizeof(ipfw_dyn_rule); 1606 } 1607 } 1608 IPFW_BUCK_UNLOCK(i); 1609 } 1610 1611 if (last != NULL) /* mark last dynamic rule */ 1612 bzero(&last->next, sizeof(last)); 1613 *pbp = bp; 1614 } 1615 /* end of file */ 1616