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