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/socket.h> 51 #include <sys/sysctl.h> 52 #include <sys/syslog.h> 53 #include <net/ethernet.h> /* for ETHERTYPE_IP */ 54 #include <net/if.h> 55 #include <net/if_var.h> 56 #include <net/vnet.h> 57 58 #include <netinet/in.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_var.h> /* ip_defttl */ 61 #include <netinet/ip_fw.h> 62 #include <netinet/tcp_var.h> 63 #include <netinet/udp.h> 64 65 #include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */ 66 #ifdef INET6 67 #include <netinet6/in6_var.h> 68 #include <netinet6/ip6_var.h> 69 #endif 70 71 #include <netpfil/ipfw/ip_fw_private.h> 72 73 #include <machine/in_cksum.h> /* XXX for in_cksum */ 74 75 #ifdef MAC 76 #include <security/mac/mac_framework.h> 77 #endif 78 79 /* 80 * Description of dynamic rules. 81 * 82 * Dynamic rules are stored in lists accessed through a hash table 83 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 84 * be modified through the sysctl variable dyn_buckets which is 85 * updated when the table becomes empty. 86 * 87 * XXX currently there is only one list, ipfw_dyn. 88 * 89 * When a packet is received, its address fields are first masked 90 * with the mask defined for the rule, then hashed, then matched 91 * against the entries in the corresponding list. 92 * Dynamic rules can be used for different purposes: 93 * + stateful rules; 94 * + enforcing limits on the number of sessions; 95 * + in-kernel NAT (not implemented yet) 96 * 97 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 98 * measured in seconds and depending on the flags. 99 * 100 * The total number of dynamic rules is equal to UMA zone items count. 101 * The max number of dynamic rules is dyn_max. When we reach 102 * the maximum number of rules we do not create anymore. This is 103 * done to avoid consuming too much memory, but also too much 104 * time when searching on each packet (ideally, we should try instead 105 * to put a limit on the length of the list on each bucket...). 106 * 107 * Each dynamic rule holds a pointer to the parent ipfw rule so 108 * we know what action to perform. Dynamic rules are removed when 109 * the parent rule is deleted. This can be changed by dyn_keep_states 110 * sysctl. 111 * 112 * There are some limitations with dynamic rules -- we do not 113 * obey the 'randomized match', and we do not do multiple 114 * passes through the firewall. XXX check the latter!!! 115 */ 116 117 struct ipfw_dyn_bucket { 118 struct mtx mtx; /* Bucket protecting lock */ 119 ipfw_dyn_rule *head; /* Pointer to first rule */ 120 }; 121 122 /* 123 * Static variables followed by global ones 124 */ 125 static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v); 126 static VNET_DEFINE(u_int32_t, dyn_buckets_max); 127 static VNET_DEFINE(u_int32_t, curr_dyn_buckets); 128 static VNET_DEFINE(struct callout, ipfw_timeout); 129 #define V_ipfw_dyn_v VNET(ipfw_dyn_v) 130 #define V_dyn_buckets_max VNET(dyn_buckets_max) 131 #define V_curr_dyn_buckets VNET(curr_dyn_buckets) 132 #define V_ipfw_timeout VNET(ipfw_timeout) 133 134 static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone); 135 #define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone) 136 137 #define IPFW_BUCK_LOCK_INIT(b) \ 138 mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF) 139 #define IPFW_BUCK_LOCK_DESTROY(b) \ 140 mtx_destroy(&(b)->mtx) 141 #define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx) 142 #define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx) 143 #define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED) 144 145 146 static VNET_DEFINE(int, dyn_keep_states); 147 #define V_dyn_keep_states VNET(dyn_keep_states) 148 149 /* 150 * Timeouts for various events in handing dynamic rules. 151 */ 152 static VNET_DEFINE(u_int32_t, dyn_ack_lifetime); 153 static VNET_DEFINE(u_int32_t, dyn_syn_lifetime); 154 static VNET_DEFINE(u_int32_t, dyn_fin_lifetime); 155 static VNET_DEFINE(u_int32_t, dyn_rst_lifetime); 156 static VNET_DEFINE(u_int32_t, dyn_udp_lifetime); 157 static VNET_DEFINE(u_int32_t, dyn_short_lifetime); 158 159 #define V_dyn_ack_lifetime VNET(dyn_ack_lifetime) 160 #define V_dyn_syn_lifetime VNET(dyn_syn_lifetime) 161 #define V_dyn_fin_lifetime VNET(dyn_fin_lifetime) 162 #define V_dyn_rst_lifetime VNET(dyn_rst_lifetime) 163 #define V_dyn_udp_lifetime VNET(dyn_udp_lifetime) 164 #define V_dyn_short_lifetime VNET(dyn_short_lifetime) 165 166 /* 167 * Keepalives are sent if dyn_keepalive is set. They are sent every 168 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 169 * seconds of lifetime of a rule. 170 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 171 * than dyn_keepalive_period. 172 */ 173 174 static VNET_DEFINE(u_int32_t, dyn_keepalive_interval); 175 static VNET_DEFINE(u_int32_t, dyn_keepalive_period); 176 static VNET_DEFINE(u_int32_t, dyn_keepalive); 177 static VNET_DEFINE(time_t, dyn_keepalive_last); 178 179 #define V_dyn_keepalive_interval VNET(dyn_keepalive_interval) 180 #define V_dyn_keepalive_period VNET(dyn_keepalive_period) 181 #define V_dyn_keepalive VNET(dyn_keepalive) 182 #define V_dyn_keepalive_last VNET(dyn_keepalive_last) 183 184 static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */ 185 186 #define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone) 187 #define V_dyn_max VNET(dyn_max) 188 189 /* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */ 190 static int ipfw_dyn_count; /* number of objects */ 191 192 #ifdef USERSPACE /* emulation of UMA object counters for userspace */ 193 #define uma_zone_get_cur(x) ipfw_dyn_count 194 #endif /* USERSPACE */ 195 196 static int last_log; /* Log ratelimiting */ 197 198 static void ipfw_dyn_tick(void *vnetx); 199 static void check_dyn_rules(struct ip_fw_chain *, struct ip_fw *, 200 int, 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_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, 210 CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0, 211 "Max number of dyn. buckets"); 212 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, 213 CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0, 214 "Current Number of dyn. buckets"); 215 SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count, 216 CTLTYPE_UINT|CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU", 217 "Number of dyn. rules"); 218 SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max, 219 CTLTYPE_UINT|CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU", 220 "Max number of dyn. rules"); 221 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, 222 CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0, 223 "Lifetime of dyn. rules for acks"); 224 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, 225 CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0, 226 "Lifetime of dyn. rules for syn"); 227 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, 228 CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0, 229 "Lifetime of dyn. rules for fin"); 230 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, 231 CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0, 232 "Lifetime of dyn. rules for rst"); 233 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, 234 CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0, 235 "Lifetime of dyn. rules for UDP"); 236 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, 237 CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0, 238 "Lifetime of dyn. rules for other situations"); 239 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, 240 CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0, 241 "Enable keepalives for dyn. rules"); 242 SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states, 243 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 static __inline int 252 hash_packet6(struct ipfw_flow_id *id) 253 { 254 u_int32_t i; 255 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 256 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 257 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 258 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^ 259 (id->dst_port) ^ (id->src_port); 260 return i; 261 } 262 263 /* 264 * IMPORTANT: the hash function for dynamic rules must be commutative 265 * in source and destination (ip,port), because rules are bidirectional 266 * and we want to find both in the same bucket. 267 */ 268 static __inline int 269 hash_packet(struct ipfw_flow_id *id, int buckets) 270 { 271 u_int32_t i; 272 273 #ifdef INET6 274 if (IS_IP6_FLOW_ID(id)) 275 i = hash_packet6(id); 276 else 277 #endif /* INET6 */ 278 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 279 i &= (buckets - 1); 280 return i; 281 } 282 283 /** 284 * Print customizable flow id description via log(9) facility. 285 */ 286 static void 287 print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags, 288 char *prefix, char *postfix) 289 { 290 struct in_addr da; 291 #ifdef INET6 292 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 293 #else 294 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 295 #endif 296 297 #ifdef INET6 298 if (IS_IP6_FLOW_ID(id)) { 299 ip6_sprintf(src, &id->src_ip6); 300 ip6_sprintf(dst, &id->dst_ip6); 301 } else 302 #endif 303 { 304 da.s_addr = htonl(id->src_ip); 305 inet_ntop(AF_INET, &da, src, sizeof(src)); 306 da.s_addr = htonl(id->dst_ip); 307 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 308 } 309 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 310 prefix, dyn_type, src, id->src_port, dst, 311 id->dst_port, DYN_COUNT, postfix); 312 } 313 314 #define print_dyn_rule(id, dtype, prefix, postfix) \ 315 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 316 317 #define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 318 #define TIME_LE(a,b) ((int)((a)-(b)) < 0) 319 320 /* 321 * Lookup a dynamic rule, locked version. 322 */ 323 static ipfw_dyn_rule * 324 lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction, 325 struct tcphdr *tcp) 326 { 327 /* 328 * Stateful ipfw extensions. 329 * Lookup into dynamic session queue. 330 */ 331 #define MATCH_REVERSE 0 332 #define MATCH_FORWARD 1 333 #define MATCH_NONE 2 334 #define MATCH_UNKNOWN 3 335 int dir = MATCH_NONE; 336 ipfw_dyn_rule *prev, *q = NULL; 337 338 IPFW_BUCK_ASSERT(i); 339 340 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 341 if (q->dyn_type == O_LIMIT_PARENT && q->count) 342 continue; 343 344 if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT) 345 continue; 346 347 if (IS_IP6_FLOW_ID(pkt)) { 348 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 349 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 350 pkt->src_port == q->id.src_port && 351 pkt->dst_port == q->id.dst_port) { 352 dir = MATCH_FORWARD; 353 break; 354 } 355 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 356 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 357 pkt->src_port == q->id.dst_port && 358 pkt->dst_port == q->id.src_port) { 359 dir = MATCH_REVERSE; 360 break; 361 } 362 } else { 363 if (pkt->src_ip == q->id.src_ip && 364 pkt->dst_ip == q->id.dst_ip && 365 pkt->src_port == q->id.src_port && 366 pkt->dst_port == q->id.dst_port) { 367 dir = MATCH_FORWARD; 368 break; 369 } 370 if (pkt->src_ip == q->id.dst_ip && 371 pkt->dst_ip == q->id.src_ip && 372 pkt->src_port == q->id.dst_port && 373 pkt->dst_port == q->id.src_port) { 374 dir = MATCH_REVERSE; 375 break; 376 } 377 } 378 } 379 if (q == NULL) 380 goto done; /* q = NULL, not found */ 381 382 if (prev != NULL) { /* found and not in front */ 383 prev->next = q->next; 384 q->next = V_ipfw_dyn_v[i].head; 385 V_ipfw_dyn_v[i].head = q; 386 } 387 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 388 uint32_t ack; 389 u_char flags = pkt->_flags & (TH_FIN | TH_SYN | TH_RST); 390 391 #define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 392 #define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 393 #define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 394 #define ACK_FWD 0x10000 /* fwd ack seen */ 395 #define ACK_REV 0x20000 /* rev ack seen */ 396 397 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 398 switch (q->state & TCP_FLAGS) { 399 case TH_SYN: /* opening */ 400 q->expire = time_uptime + V_dyn_syn_lifetime; 401 break; 402 403 case BOTH_SYN: /* move to established */ 404 case BOTH_SYN | TH_FIN: /* one side tries to close */ 405 case BOTH_SYN | (TH_FIN << 8): 406 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 407 if (tcp == NULL) 408 break; 409 410 ack = ntohl(tcp->th_ack); 411 if (dir == MATCH_FORWARD) { 412 if (q->ack_fwd == 0 || 413 _SEQ_GE(ack, q->ack_fwd)) { 414 q->ack_fwd = ack; 415 q->state |= ACK_FWD; 416 } 417 } else { 418 if (q->ack_rev == 0 || 419 _SEQ_GE(ack, q->ack_rev)) { 420 q->ack_rev = ack; 421 q->state |= ACK_REV; 422 } 423 } 424 if ((q->state & (ACK_FWD | ACK_REV)) == 425 (ACK_FWD | ACK_REV)) { 426 q->expire = time_uptime + V_dyn_ack_lifetime; 427 q->state &= ~(ACK_FWD | ACK_REV); 428 } 429 break; 430 431 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 432 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 433 V_dyn_fin_lifetime = V_dyn_keepalive_period - 1; 434 q->expire = time_uptime + V_dyn_fin_lifetime; 435 break; 436 437 default: 438 #if 0 439 /* 440 * reset or some invalid combination, but can also 441 * occur if we use keep-state the wrong way. 442 */ 443 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 444 printf("invalid state: 0x%x\n", q->state); 445 #endif 446 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 447 V_dyn_rst_lifetime = V_dyn_keepalive_period - 1; 448 q->expire = time_uptime + V_dyn_rst_lifetime; 449 break; 450 } 451 } else if (pkt->proto == IPPROTO_UDP) { 452 q->expire = time_uptime + V_dyn_udp_lifetime; 453 } else { 454 /* other protocols */ 455 q->expire = time_uptime + V_dyn_short_lifetime; 456 } 457 done: 458 if (match_direction != NULL) 459 *match_direction = dir; 460 return (q); 461 } 462 463 ipfw_dyn_rule * 464 ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 465 struct tcphdr *tcp) 466 { 467 ipfw_dyn_rule *q; 468 int i; 469 470 i = hash_packet(pkt, V_curr_dyn_buckets); 471 472 IPFW_BUCK_LOCK(i); 473 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp); 474 if (q == NULL) 475 IPFW_BUCK_UNLOCK(i); 476 /* NB: return table locked when q is not NULL */ 477 return q; 478 } 479 480 /* 481 * Unlock bucket mtx 482 * @p - pointer to dynamic rule 483 */ 484 void 485 ipfw_dyn_unlock(ipfw_dyn_rule *q) 486 { 487 488 IPFW_BUCK_UNLOCK(q->bucket); 489 } 490 491 static int 492 resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 493 { 494 int i, k, nbuckets_old; 495 ipfw_dyn_rule *q; 496 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 497 498 /* Check if given number is power of 2 and less than 64k */ 499 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 500 return 1; 501 502 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 503 V_curr_dyn_buckets, nbuckets); 504 505 /* Allocate and initialize new hash */ 506 dyn_v = malloc(nbuckets * sizeof(ipfw_dyn_rule), M_IPFW, 507 M_WAITOK | M_ZERO); 508 509 for (i = 0 ; i < nbuckets; i++) 510 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 511 512 /* 513 * Call upper half lock, as get_map() do to ease 514 * read-only access to dynamic rules hash from sysctl 515 */ 516 IPFW_UH_WLOCK(chain); 517 518 /* 519 * Acquire chain write lock to permit hash access 520 * for main traffic path without additional locks 521 */ 522 IPFW_WLOCK(chain); 523 524 /* Save old values */ 525 nbuckets_old = V_curr_dyn_buckets; 526 dyn_v_old = V_ipfw_dyn_v; 527 528 /* Skip relinking if array is not set up */ 529 if (V_ipfw_dyn_v == NULL) 530 V_curr_dyn_buckets = 0; 531 532 /* Re-link all dynamic states */ 533 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 534 while (V_ipfw_dyn_v[i].head != NULL) { 535 /* Remove from current chain */ 536 q = V_ipfw_dyn_v[i].head; 537 V_ipfw_dyn_v[i].head = q->next; 538 539 /* Get new hash value */ 540 k = hash_packet(&q->id, nbuckets); 541 q->bucket = k; 542 /* Add to the new head */ 543 q->next = dyn_v[k].head; 544 dyn_v[k].head = q; 545 } 546 } 547 548 /* Update current pointers/buckets values */ 549 V_curr_dyn_buckets = nbuckets; 550 V_ipfw_dyn_v = dyn_v; 551 552 IPFW_WUNLOCK(chain); 553 554 IPFW_UH_WUNLOCK(chain); 555 556 /* Start periodic callout on initial creation */ 557 if (dyn_v_old == NULL) { 558 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 559 return (0); 560 } 561 562 /* Destroy all mutexes */ 563 for (i = 0 ; i < nbuckets_old ; i++) 564 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 565 566 /* Free old hash */ 567 free(dyn_v_old, M_IPFW); 568 569 return 0; 570 } 571 572 /** 573 * Install state of type 'type' for a dynamic session. 574 * The hash table contains two type of rules: 575 * - regular rules (O_KEEP_STATE) 576 * - rules for sessions with limited number of sess per user 577 * (O_LIMIT). When they are created, the parent is 578 * increased by 1, and decreased on delete. In this case, 579 * the third parameter is the parent rule and not the chain. 580 * - "parent" rules for the above (O_LIMIT_PARENT). 581 */ 582 static ipfw_dyn_rule * 583 add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule) 584 { 585 ipfw_dyn_rule *r; 586 587 IPFW_BUCK_ASSERT(i); 588 589 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 590 if (r == NULL) { 591 if (last_log != time_uptime) { 592 last_log = time_uptime; 593 log(LOG_DEBUG, "ipfw: %s: Cannot allocate rule\n", 594 __func__); 595 } 596 return NULL; 597 } 598 ipfw_dyn_count++; 599 600 /* 601 * refcount on parent is already incremented, so 602 * it is safe to use parent unlocked. 603 */ 604 if (dyn_type == O_LIMIT) { 605 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 606 if ( parent->dyn_type != O_LIMIT_PARENT) 607 panic("invalid parent"); 608 r->parent = parent; 609 rule = parent->rule; 610 } 611 612 r->id = *id; 613 r->expire = time_uptime + V_dyn_syn_lifetime; 614 r->rule = rule; 615 r->dyn_type = dyn_type; 616 IPFW_ZERO_DYN_COUNTER(r); 617 r->count = 0; 618 619 r->bucket = i; 620 r->next = V_ipfw_dyn_v[i].head; 621 V_ipfw_dyn_v[i].head = r; 622 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 623 return r; 624 } 625 626 /** 627 * lookup dynamic parent rule using pkt and rule as search keys. 628 * If the lookup fails, then install one. 629 */ 630 static ipfw_dyn_rule * 631 lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule) 632 { 633 ipfw_dyn_rule *q; 634 int i, is_v6; 635 636 is_v6 = IS_IP6_FLOW_ID(pkt); 637 i = hash_packet( pkt, V_curr_dyn_buckets ); 638 *pindex = i; 639 IPFW_BUCK_LOCK(i); 640 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 641 if (q->dyn_type == O_LIMIT_PARENT && 642 rule== q->rule && 643 pkt->proto == q->id.proto && 644 pkt->src_port == q->id.src_port && 645 pkt->dst_port == q->id.dst_port && 646 ( 647 (is_v6 && 648 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 649 &(q->id.src_ip6)) && 650 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 651 &(q->id.dst_ip6))) || 652 (!is_v6 && 653 pkt->src_ip == q->id.src_ip && 654 pkt->dst_ip == q->id.dst_ip) 655 ) 656 ) { 657 q->expire = time_uptime + V_dyn_short_lifetime; 658 DEB(print_dyn_rule(pkt, q->dyn_type, 659 "lookup_dyn_parent found", "");) 660 return q; 661 } 662 663 /* Add virtual limiting rule */ 664 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule); 665 } 666 667 /** 668 * Install dynamic state for rule type cmd->o.opcode 669 * 670 * Returns 1 (failure) if state is not installed because of errors or because 671 * session limitations are enforced. 672 */ 673 int 674 ipfw_install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 675 struct ip_fw_args *args, uint32_t tablearg) 676 { 677 ipfw_dyn_rule *q; 678 int i; 679 680 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");) 681 682 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 683 684 IPFW_BUCK_LOCK(i); 685 686 q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 687 688 if (q != NULL) { /* should never occur */ 689 DEB( 690 if (last_log != time_uptime) { 691 last_log = time_uptime; 692 printf("ipfw: %s: entry already present, done\n", 693 __func__); 694 }) 695 IPFW_BUCK_UNLOCK(i); 696 return (0); 697 } 698 699 /* 700 * State limiting is done via uma(9) zone limiting. 701 * Save pointer to newly-installed rule and reject 702 * packet if add_dyn_rule() returned NULL. 703 * Note q is currently set to NULL. 704 */ 705 706 switch (cmd->o.opcode) { 707 case O_KEEP_STATE: /* bidir rule */ 708 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule); 709 break; 710 711 case O_LIMIT: { /* limit number of sessions */ 712 struct ipfw_flow_id id; 713 ipfw_dyn_rule *parent; 714 uint32_t conn_limit; 715 uint16_t limit_mask = cmd->limit_mask; 716 int pindex; 717 718 conn_limit = IP_FW_ARG_TABLEARG(cmd->conn_limit); 719 720 DEB( 721 if (cmd->conn_limit == IP_FW_TABLEARG) 722 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 723 "(tablearg)\n", __func__, conn_limit); 724 else 725 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 726 __func__, conn_limit); 727 ) 728 729 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 730 id.proto = args->f_id.proto; 731 id.addr_type = args->f_id.addr_type; 732 id.fib = M_GETFIB(args->m); 733 734 if (IS_IP6_FLOW_ID (&(args->f_id))) { 735 if (limit_mask & DYN_SRC_ADDR) 736 id.src_ip6 = args->f_id.src_ip6; 737 if (limit_mask & DYN_DST_ADDR) 738 id.dst_ip6 = args->f_id.dst_ip6; 739 } else { 740 if (limit_mask & DYN_SRC_ADDR) 741 id.src_ip = args->f_id.src_ip; 742 if (limit_mask & DYN_DST_ADDR) 743 id.dst_ip = args->f_id.dst_ip; 744 } 745 if (limit_mask & DYN_SRC_PORT) 746 id.src_port = args->f_id.src_port; 747 if (limit_mask & DYN_DST_PORT) 748 id.dst_port = args->f_id.dst_port; 749 750 /* 751 * We have to release lock for previous bucket to 752 * avoid possible deadlock 753 */ 754 IPFW_BUCK_UNLOCK(i); 755 756 if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) { 757 printf("ipfw: %s: add parent failed\n", __func__); 758 IPFW_BUCK_UNLOCK(pindex); 759 return (1); 760 } 761 762 if (parent->count >= conn_limit) { 763 if (V_fw_verbose && last_log != time_uptime) { 764 last_log = time_uptime; 765 char sbuf[24]; 766 last_log = time_uptime; 767 snprintf(sbuf, sizeof(sbuf), 768 "%d drop session", 769 parent->rule->rulenum); 770 print_dyn_rule_flags(&args->f_id, 771 cmd->o.opcode, 772 LOG_SECURITY | LOG_DEBUG, 773 sbuf, "too many entries"); 774 } 775 IPFW_BUCK_UNLOCK(pindex); 776 return (1); 777 } 778 /* Increment counter on parent */ 779 parent->count++; 780 IPFW_BUCK_UNLOCK(pindex); 781 782 IPFW_BUCK_LOCK(i); 783 q = add_dyn_rule(&args->f_id, i, O_LIMIT, (struct ip_fw *)parent); 784 if (q == NULL) { 785 /* Decrement index and notify caller */ 786 IPFW_BUCK_UNLOCK(i); 787 IPFW_BUCK_LOCK(pindex); 788 parent->count--; 789 IPFW_BUCK_UNLOCK(pindex); 790 return (1); 791 } 792 break; 793 } 794 default: 795 printf("ipfw: %s: unknown dynamic rule type %u\n", 796 __func__, cmd->o.opcode); 797 } 798 799 if (q == NULL) { 800 IPFW_BUCK_UNLOCK(i); 801 return (1); /* Notify caller about failure */ 802 } 803 804 /* XXX just set lifetime */ 805 lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 806 807 IPFW_BUCK_UNLOCK(i); 808 return (0); 809 } 810 811 /* 812 * Generate a TCP packet, containing either a RST or a keepalive. 813 * When flags & TH_RST, we are sending a RST packet, because of a 814 * "reset" action matched the packet. 815 * Otherwise we are sending a keepalive, and flags & TH_ 816 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 817 * so that MAC can label the reply appropriately. 818 */ 819 struct mbuf * 820 ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 821 u_int32_t ack, int flags) 822 { 823 struct mbuf *m = NULL; /* stupid compiler */ 824 int len, dir; 825 struct ip *h = NULL; /* stupid compiler */ 826 #ifdef INET6 827 struct ip6_hdr *h6 = NULL; 828 #endif 829 struct tcphdr *th = NULL; 830 831 MGETHDR(m, M_NOWAIT, MT_DATA); 832 if (m == NULL) 833 return (NULL); 834 835 M_SETFIB(m, id->fib); 836 #ifdef MAC 837 if (replyto != NULL) 838 mac_netinet_firewall_reply(replyto, m); 839 else 840 mac_netinet_firewall_send(m); 841 #else 842 (void)replyto; /* don't warn about unused arg */ 843 #endif 844 845 switch (id->addr_type) { 846 case 4: 847 len = sizeof(struct ip) + sizeof(struct tcphdr); 848 break; 849 #ifdef INET6 850 case 6: 851 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 852 break; 853 #endif 854 default: 855 /* XXX: log me?!? */ 856 FREE_PKT(m); 857 return (NULL); 858 } 859 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 860 861 m->m_data += max_linkhdr; 862 m->m_flags |= M_SKIP_FIREWALL; 863 m->m_pkthdr.len = m->m_len = len; 864 m->m_pkthdr.rcvif = NULL; 865 bzero(m->m_data, len); 866 867 switch (id->addr_type) { 868 case 4: 869 h = mtod(m, struct ip *); 870 871 /* prepare for checksum */ 872 h->ip_p = IPPROTO_TCP; 873 h->ip_len = htons(sizeof(struct tcphdr)); 874 if (dir) { 875 h->ip_src.s_addr = htonl(id->src_ip); 876 h->ip_dst.s_addr = htonl(id->dst_ip); 877 } else { 878 h->ip_src.s_addr = htonl(id->dst_ip); 879 h->ip_dst.s_addr = htonl(id->src_ip); 880 } 881 882 th = (struct tcphdr *)(h + 1); 883 break; 884 #ifdef INET6 885 case 6: 886 h6 = mtod(m, struct ip6_hdr *); 887 888 /* prepare for checksum */ 889 h6->ip6_nxt = IPPROTO_TCP; 890 h6->ip6_plen = htons(sizeof(struct tcphdr)); 891 if (dir) { 892 h6->ip6_src = id->src_ip6; 893 h6->ip6_dst = id->dst_ip6; 894 } else { 895 h6->ip6_src = id->dst_ip6; 896 h6->ip6_dst = id->src_ip6; 897 } 898 899 th = (struct tcphdr *)(h6 + 1); 900 break; 901 #endif 902 } 903 904 if (dir) { 905 th->th_sport = htons(id->src_port); 906 th->th_dport = htons(id->dst_port); 907 } else { 908 th->th_sport = htons(id->dst_port); 909 th->th_dport = htons(id->src_port); 910 } 911 th->th_off = sizeof(struct tcphdr) >> 2; 912 913 if (flags & TH_RST) { 914 if (flags & TH_ACK) { 915 th->th_seq = htonl(ack); 916 th->th_flags = TH_RST; 917 } else { 918 if (flags & TH_SYN) 919 seq++; 920 th->th_ack = htonl(seq); 921 th->th_flags = TH_RST | TH_ACK; 922 } 923 } else { 924 /* 925 * Keepalive - use caller provided sequence numbers 926 */ 927 th->th_seq = htonl(seq); 928 th->th_ack = htonl(ack); 929 th->th_flags = TH_ACK; 930 } 931 932 switch (id->addr_type) { 933 case 4: 934 th->th_sum = in_cksum(m, len); 935 936 /* finish the ip header */ 937 h->ip_v = 4; 938 h->ip_hl = sizeof(*h) >> 2; 939 h->ip_tos = IPTOS_LOWDELAY; 940 h->ip_off = htons(0); 941 h->ip_len = htons(len); 942 h->ip_ttl = V_ip_defttl; 943 h->ip_sum = 0; 944 break; 945 #ifdef INET6 946 case 6: 947 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 948 sizeof(struct tcphdr)); 949 950 /* finish the ip6 header */ 951 h6->ip6_vfc |= IPV6_VERSION; 952 h6->ip6_hlim = IPV6_DEFHLIM; 953 break; 954 #endif 955 } 956 957 return (m); 958 } 959 960 /* 961 * Queue keepalive packets for given dynamic rule 962 */ 963 static struct mbuf ** 964 ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 965 { 966 struct mbuf *m_rev, *m_fwd; 967 968 m_rev = (q->state & ACK_REV) ? NULL : 969 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 970 m_fwd = (q->state & ACK_FWD) ? NULL : 971 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 972 973 if (m_rev != NULL) { 974 *mtailp = m_rev; 975 mtailp = &(*mtailp)->m_nextpkt; 976 } 977 if (m_fwd != NULL) { 978 *mtailp = m_fwd; 979 mtailp = &(*mtailp)->m_nextpkt; 980 } 981 982 return (mtailp); 983 } 984 985 /* 986 * This procedure is used to perform various maintance 987 * on dynamic hash list. Currently it is called every second. 988 */ 989 static void 990 ipfw_dyn_tick(void * vnetx) 991 { 992 struct ip_fw_chain *chain; 993 int check_ka = 0; 994 #ifdef VIMAGE 995 struct vnet *vp = vnetx; 996 #endif 997 998 CURVNET_SET(vp); 999 1000 chain = &V_layer3_chain; 1001 1002 /* Run keepalive checks every keepalive_period iff ka is enabled */ 1003 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 1004 (V_dyn_keepalive != 0)) { 1005 V_dyn_keepalive_last = time_uptime; 1006 check_ka = 1; 1007 } 1008 1009 check_dyn_rules(chain, NULL, RESVD_SET, check_ka, 1); 1010 1011 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 1012 1013 CURVNET_RESTORE(); 1014 } 1015 1016 1017 /* 1018 * Walk thru all dynamic states doing generic maintance: 1019 * 1) free expired states 1020 * 2) free all states based on deleted rule / set 1021 * 3) send keepalives for states if needed 1022 * 1023 * @chain - pointer to current ipfw rules chain 1024 * @rule - delete all states originated by given rule if != NULL 1025 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1026 * @check_ka - perform checking/sending keepalives 1027 * @timer - indicate call from timer routine. 1028 * 1029 * Timer routine must call this function unlocked to permit 1030 * sending keepalives/resizing table. 1031 * 1032 * Others has to call function with IPFW_UH_WLOCK held. 1033 * Additionally, function assume that dynamic rule/set is 1034 * ALREADY deleted so no new states can be generated by 1035 * 'deleted' rules. 1036 * 1037 * Write lock is needed to ensure that unused parent rules 1038 * are not freed by other instance (see stage 2, 3) 1039 */ 1040 static void 1041 check_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, 1042 int set, int check_ka, int timer) 1043 { 1044 struct mbuf *m0, *m, *mnext, **mtailp; 1045 struct ip *h; 1046 int i, dyn_count, new_buckets = 0, max_buckets; 1047 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1048 ipfw_dyn_rule *q, *q_prev, *q_next; 1049 ipfw_dyn_rule *exp_head, **exptailp; 1050 ipfw_dyn_rule *exp_lhead, **expltailp; 1051 1052 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1053 __func__)); 1054 1055 /* Avoid possible LOR */ 1056 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1057 __func__)); 1058 1059 /* 1060 * Do not perform any checks if we currently have no dynamic states 1061 */ 1062 if (DYN_COUNT == 0) 1063 return; 1064 1065 /* Expired states */ 1066 exp_head = NULL; 1067 exptailp = &exp_head; 1068 1069 /* Expired limit states */ 1070 exp_lhead = NULL; 1071 expltailp = &exp_lhead; 1072 1073 /* 1074 * We make a chain of packets to go out here -- not deferring 1075 * until after we drop the IPFW dynamic rule lock would result 1076 * in a lock order reversal with the normal packet input -> ipfw 1077 * call stack. 1078 */ 1079 m0 = NULL; 1080 mtailp = &m0; 1081 1082 /* Protect from hash resizing */ 1083 if (timer != 0) 1084 IPFW_UH_WLOCK(chain); 1085 else 1086 IPFW_UH_WLOCK_ASSERT(chain); 1087 1088 #define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1089 1090 /* Stage 1: perform requested deletion */ 1091 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1092 IPFW_BUCK_LOCK(i); 1093 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1094 /* account every rule */ 1095 total++; 1096 1097 /* Skip parent rules at all */ 1098 if (q->dyn_type == O_LIMIT_PARENT) { 1099 parents++; 1100 NEXT_RULE(); 1101 } 1102 1103 /* 1104 * Remove rules which are: 1105 * 1) expired 1106 * 2) created by given rule 1107 * 3) created by any rule in given set 1108 */ 1109 if ((TIME_LEQ(q->expire, time_uptime)) || 1110 ((rule != NULL) && (q->rule == rule)) || 1111 ((set != RESVD_SET) && (q->rule->set == set))) { 1112 if (TIME_LE(time_uptime, q->expire) && 1113 q->dyn_type == O_KEEP_STATE && 1114 V_dyn_keep_states != 0) { 1115 /* 1116 * Do not delete state if 1117 * it is not expired and 1118 * dyn_keep_states is ON. 1119 * However we need to re-link it 1120 * to any other stable rule 1121 */ 1122 q->rule = chain->default_rule; 1123 NEXT_RULE(); 1124 } 1125 1126 /* Unlink q from current list */ 1127 q_next = q->next; 1128 if (q == V_ipfw_dyn_v[i].head) 1129 V_ipfw_dyn_v[i].head = q_next; 1130 else 1131 q_prev->next = q_next; 1132 1133 q->next = NULL; 1134 1135 /* queue q to expire list */ 1136 if (q->dyn_type != O_LIMIT) { 1137 *exptailp = q; 1138 exptailp = &(*exptailp)->next; 1139 DEB(print_dyn_rule(&q->id, q->dyn_type, 1140 "unlink entry", "left"); 1141 ) 1142 } else { 1143 /* Separate list for limit rules */ 1144 *expltailp = q; 1145 expltailp = &(*expltailp)->next; 1146 expired_limits++; 1147 DEB(print_dyn_rule(&q->id, q->dyn_type, 1148 "unlink limit entry", "left"); 1149 ) 1150 } 1151 1152 q = q_next; 1153 expired++; 1154 continue; 1155 } 1156 1157 /* 1158 * Check if we need to send keepalive: 1159 * we need to ensure if is time to do KA, 1160 * this is established TCP session, and 1161 * expire time is within keepalive interval 1162 */ 1163 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1164 ((q->state & BOTH_SYN) == BOTH_SYN) && 1165 (TIME_LEQ(q->expire, time_uptime + 1166 V_dyn_keepalive_interval))) 1167 mtailp = ipfw_dyn_send_ka(mtailp, q); 1168 1169 NEXT_RULE(); 1170 } 1171 IPFW_BUCK_UNLOCK(i); 1172 } 1173 1174 /* Stage 2: decrement counters from O_LIMIT parents */ 1175 if (expired_limits != 0) { 1176 /* 1177 * XXX: Note that deleting set with more than one 1178 * heavily-used LIMIT rules can result in overwhelming 1179 * locking due to lack of per-hash value sorting 1180 * 1181 * We should probably think about: 1182 * 1) pre-allocating hash of size, say, 1183 * MAX(16, V_curr_dyn_buckets / 1024) 1184 * 2) checking if expired_limits is large enough 1185 * 3) If yes, init hash (or its part), re-link 1186 * current list and start decrementing procedure in 1187 * each bucket separately 1188 */ 1189 1190 /* 1191 * Small optimization: do not unlock bucket until 1192 * we see the next item resides in different bucket 1193 */ 1194 if (exp_lhead != NULL) { 1195 i = exp_lhead->parent->bucket; 1196 IPFW_BUCK_LOCK(i); 1197 } 1198 for (q = exp_lhead; q != NULL; q = q->next) { 1199 if (i != q->parent->bucket) { 1200 IPFW_BUCK_UNLOCK(i); 1201 i = q->parent->bucket; 1202 IPFW_BUCK_LOCK(i); 1203 } 1204 1205 /* Decrease parent refcount */ 1206 q->parent->count--; 1207 } 1208 if (exp_lhead != NULL) 1209 IPFW_BUCK_UNLOCK(i); 1210 } 1211 1212 /* 1213 * We protectet ourselves from unused parent deletion 1214 * (from the timer function) by holding UH write lock. 1215 */ 1216 1217 /* Stage 3: remove unused parent rules */ 1218 if ((parents != 0) && (expired != 0)) { 1219 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1220 IPFW_BUCK_LOCK(i); 1221 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1222 if (q->dyn_type != O_LIMIT_PARENT) 1223 NEXT_RULE(); 1224 1225 if (q->count != 0) 1226 NEXT_RULE(); 1227 1228 /* Parent rule without consumers */ 1229 1230 /* Unlink q from current list */ 1231 q_next = q->next; 1232 if (q == V_ipfw_dyn_v[i].head) 1233 V_ipfw_dyn_v[i].head = q_next; 1234 else 1235 q_prev->next = q_next; 1236 1237 q->next = NULL; 1238 1239 /* Add to expired list */ 1240 *exptailp = q; 1241 exptailp = &(*exptailp)->next; 1242 1243 DEB(print_dyn_rule(&q->id, q->dyn_type, 1244 "unlink parent entry", "left"); 1245 ) 1246 1247 expired++; 1248 1249 q = q_next; 1250 } 1251 IPFW_BUCK_UNLOCK(i); 1252 } 1253 } 1254 1255 #undef NEXT_RULE 1256 1257 if (timer != 0) { 1258 /* 1259 * Check if we need to resize hash: 1260 * if current number of states exceeds number of buckes in hash, 1261 * grow hash size to the minimum power of 2 which is bigger than 1262 * current states count. Limit hash size by 64k. 1263 */ 1264 max_buckets = (V_dyn_buckets_max > 65536) ? 1265 65536 : V_dyn_buckets_max; 1266 1267 dyn_count = DYN_COUNT; 1268 1269 if ((dyn_count > V_curr_dyn_buckets * 2) && 1270 (dyn_count < max_buckets)) { 1271 new_buckets = V_curr_dyn_buckets; 1272 while (new_buckets < dyn_count) { 1273 new_buckets *= 2; 1274 1275 if (new_buckets >= max_buckets) 1276 break; 1277 } 1278 } 1279 1280 IPFW_UH_WUNLOCK(chain); 1281 } 1282 1283 /* Finally delete old states ad limits if any */ 1284 for (q = exp_head; q != NULL; q = q_next) { 1285 q_next = q->next; 1286 uma_zfree(V_ipfw_dyn_rule_zone, q); 1287 ipfw_dyn_count--; 1288 } 1289 1290 for (q = exp_lhead; q != NULL; q = q_next) { 1291 q_next = q->next; 1292 uma_zfree(V_ipfw_dyn_rule_zone, q); 1293 ipfw_dyn_count--; 1294 } 1295 1296 /* 1297 * The rest code MUST be called from timer routine only 1298 * without holding any locks 1299 */ 1300 if (timer == 0) 1301 return; 1302 1303 /* Send keepalive packets if any */ 1304 for (m = m0; m != NULL; m = mnext) { 1305 mnext = m->m_nextpkt; 1306 m->m_nextpkt = NULL; 1307 h = mtod(m, struct ip *); 1308 if (h->ip_v == 4) 1309 ip_output(m, NULL, NULL, 0, NULL, NULL); 1310 #ifdef INET6 1311 else 1312 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1313 #endif 1314 } 1315 1316 /* Run table resize without holding any locks */ 1317 if (new_buckets != 0) 1318 resize_dynamic_table(chain, new_buckets); 1319 } 1320 1321 /* 1322 * Deletes all dynamic rules originated by given rule or all rules in 1323 * given set. Specify RESVD_SET to indicate set should not be used. 1324 * @chain - pointer to current ipfw rules chain 1325 * @rule - delete all states originated by given rule if != NULL 1326 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1327 * 1328 * Function has to be called with IPFW_UH_WLOCK held. 1329 * Additionally, function assume that dynamic rule/set is 1330 * ALREADY deleted so no new states can be generated by 1331 * 'deleted' rules. 1332 */ 1333 void 1334 ipfw_expire_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, int set) 1335 { 1336 1337 check_dyn_rules(chain, rule, set, 0, 0); 1338 } 1339 1340 void 1341 ipfw_dyn_init(struct ip_fw_chain *chain) 1342 { 1343 1344 V_ipfw_dyn_v = NULL; 1345 V_dyn_buckets_max = 256; /* must be power of 2 */ 1346 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1347 1348 V_dyn_ack_lifetime = 300; 1349 V_dyn_syn_lifetime = 20; 1350 V_dyn_fin_lifetime = 1; 1351 V_dyn_rst_lifetime = 1; 1352 V_dyn_udp_lifetime = 10; 1353 V_dyn_short_lifetime = 5; 1354 1355 V_dyn_keepalive_interval = 20; 1356 V_dyn_keepalive_period = 5; 1357 V_dyn_keepalive = 1; /* do send keepalives */ 1358 V_dyn_keepalive_last = time_uptime; 1359 1360 V_dyn_max = 4096; /* max # of dynamic rules */ 1361 1362 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1363 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1364 UMA_ALIGN_PTR, 0); 1365 1366 /* Enforce limit on dynamic rules */ 1367 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1368 1369 callout_init(&V_ipfw_timeout, CALLOUT_MPSAFE); 1370 1371 /* 1372 * This can potentially be done on first dynamic rule 1373 * being added to chain. 1374 */ 1375 resize_dynamic_table(chain, V_curr_dyn_buckets); 1376 } 1377 1378 void 1379 ipfw_dyn_uninit(int pass) 1380 { 1381 int i; 1382 1383 if (pass == 0) { 1384 callout_drain(&V_ipfw_timeout); 1385 return; 1386 } 1387 1388 if (V_ipfw_dyn_v != NULL) { 1389 /* 1390 * Skip deleting all dynamic states - 1391 * uma_zdestroy() does this more efficiently; 1392 */ 1393 1394 /* Destroy all mutexes */ 1395 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1396 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1397 free(V_ipfw_dyn_v, M_IPFW); 1398 V_ipfw_dyn_v = NULL; 1399 } 1400 1401 uma_zdestroy(V_ipfw_dyn_rule_zone); 1402 } 1403 1404 #ifdef SYSCTL_NODE 1405 /* 1406 * Get/set maximum number of dynamic states in given VNET instance. 1407 */ 1408 static int 1409 sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1410 { 1411 int error; 1412 unsigned int nstates; 1413 1414 nstates = V_dyn_max; 1415 1416 error = sysctl_handle_int(oidp, &nstates, 0, req); 1417 /* Read operation or some error */ 1418 if ((error != 0) || (req->newptr == NULL)) 1419 return (error); 1420 1421 V_dyn_max = nstates; 1422 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1423 1424 return (0); 1425 } 1426 1427 /* 1428 * Get current number of dynamic states in given VNET instance. 1429 */ 1430 static int 1431 sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1432 { 1433 int error; 1434 unsigned int nstates; 1435 1436 nstates = DYN_COUNT; 1437 1438 error = sysctl_handle_int(oidp, &nstates, 0, req); 1439 1440 return (error); 1441 } 1442 #endif 1443 1444 /* 1445 * Returns number of dynamic rules. 1446 */ 1447 int 1448 ipfw_dyn_len(void) 1449 { 1450 1451 return (V_ipfw_dyn_v == NULL) ? 0 : 1452 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1453 } 1454 1455 /* 1456 * Fill given buffer with dynamic states. 1457 * IPFW_UH_RLOCK has to be held while calling. 1458 */ 1459 void 1460 ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1461 { 1462 ipfw_dyn_rule *p, *last = NULL; 1463 char *bp; 1464 int i; 1465 1466 if (V_ipfw_dyn_v == NULL) 1467 return; 1468 bp = *pbp; 1469 1470 IPFW_UH_RLOCK_ASSERT(chain); 1471 1472 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1473 IPFW_BUCK_LOCK(i); 1474 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1475 if (bp + sizeof *p <= ep) { 1476 ipfw_dyn_rule *dst = 1477 (ipfw_dyn_rule *)bp; 1478 bcopy(p, dst, sizeof *p); 1479 bcopy(&(p->rule->rulenum), &(dst->rule), 1480 sizeof(p->rule->rulenum)); 1481 /* 1482 * store set number into high word of 1483 * dst->rule pointer. 1484 */ 1485 bcopy(&(p->rule->set), 1486 (char *)&dst->rule + 1487 sizeof(p->rule->rulenum), 1488 sizeof(p->rule->set)); 1489 /* 1490 * store a non-null value in "next". 1491 * The userland code will interpret a 1492 * NULL here as a marker 1493 * for the last dynamic rule. 1494 */ 1495 bcopy(&dst, &dst->next, sizeof(dst)); 1496 last = dst; 1497 dst->expire = 1498 TIME_LEQ(dst->expire, time_uptime) ? 1499 0 : dst->expire - time_uptime ; 1500 bp += sizeof(ipfw_dyn_rule); 1501 } 1502 } 1503 IPFW_BUCK_UNLOCK(i); 1504 } 1505 1506 if (last != NULL) /* mark last dynamic rule */ 1507 bzero(&last->next, sizeof(last)); 1508 *pbp = bp; 1509 } 1510 /* end of file */ 1511