ip_fw_dynamic.c revision 314667
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: stable/10/sys/netpfil/ipfw/ip_fw_dynamic.c 314667 2017-03-04 13:03:31Z avg $"); 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/lock.h> 49#include <sys/socket.h> 50#include <sys/sysctl.h> 51#include <sys/syslog.h> 52#include <net/ethernet.h> /* for ETHERTYPE_IP */ 53#include <net/if.h> 54#include <net/vnet.h> 55 56#include <netinet/in.h> 57#include <netinet/ip.h> 58#include <netinet/ip_var.h> /* ip_defttl */ 59#include <netinet/ip_fw.h> 60#include <netinet/tcp_var.h> 61#include <netinet/udp.h> 62 63#include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */ 64#ifdef INET6 65#include <netinet6/in6_var.h> 66#include <netinet6/ip6_var.h> 67#endif 68 69#include <netpfil/ipfw/ip_fw_private.h> 70 71#include <machine/in_cksum.h> /* XXX for in_cksum */ 72 73#ifdef MAC 74#include <security/mac/mac_framework.h> 75#endif 76 77/* 78 * Description of dynamic rules. 79 * 80 * Dynamic rules are stored in lists accessed through a hash table 81 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 82 * be modified through the sysctl variable dyn_buckets which is 83 * updated when the table becomes empty. 84 * 85 * XXX currently there is only one list, ipfw_dyn. 86 * 87 * When a packet is received, its address fields are first masked 88 * with the mask defined for the rule, then hashed, then matched 89 * against the entries in the corresponding list. 90 * Dynamic rules can be used for different purposes: 91 * + stateful rules; 92 * + enforcing limits on the number of sessions; 93 * + in-kernel NAT (not implemented yet) 94 * 95 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 96 * measured in seconds and depending on the flags. 97 * 98 * The total number of dynamic rules is equal to UMA zone items count. 99 * The max number of dynamic rules is dyn_max. When we reach 100 * the maximum number of rules we do not create anymore. This is 101 * done to avoid consuming too much memory, but also too much 102 * time when searching on each packet (ideally, we should try instead 103 * to put a limit on the length of the list on each bucket...). 104 * 105 * Each dynamic rule holds a pointer to the parent ipfw rule so 106 * we know what action to perform. Dynamic rules are removed when 107 * the parent rule is deleted. XXX we should make them survive. 108 * 109 * There are some limitations with dynamic rules -- we do not 110 * obey the 'randomized match', and we do not do multiple 111 * passes through the firewall. XXX check the latter!!! 112 */ 113 114struct ipfw_dyn_bucket { 115 struct mtx mtx; /* Bucket protecting lock */ 116 ipfw_dyn_rule *head; /* Pointer to first rule */ 117}; 118 119/* 120 * Static variables followed by global ones 121 */ 122static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v); 123static VNET_DEFINE(u_int32_t, dyn_buckets_max); 124static VNET_DEFINE(u_int32_t, curr_dyn_buckets); 125static VNET_DEFINE(struct callout, ipfw_timeout); 126#define V_ipfw_dyn_v VNET(ipfw_dyn_v) 127#define V_dyn_buckets_max VNET(dyn_buckets_max) 128#define V_curr_dyn_buckets VNET(curr_dyn_buckets) 129#define V_ipfw_timeout VNET(ipfw_timeout) 130 131static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone); 132#define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone) 133 134#define IPFW_BUCK_LOCK_INIT(b) \ 135 mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF) 136#define IPFW_BUCK_LOCK_DESTROY(b) \ 137 mtx_destroy(&(b)->mtx) 138#define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx) 139#define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx) 140#define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED) 141 142/* 143 * Timeouts for various events in handing dynamic rules. 144 */ 145static VNET_DEFINE(u_int32_t, dyn_ack_lifetime); 146static VNET_DEFINE(u_int32_t, dyn_syn_lifetime); 147static VNET_DEFINE(u_int32_t, dyn_fin_lifetime); 148static VNET_DEFINE(u_int32_t, dyn_rst_lifetime); 149static VNET_DEFINE(u_int32_t, dyn_udp_lifetime); 150static VNET_DEFINE(u_int32_t, dyn_short_lifetime); 151 152#define V_dyn_ack_lifetime VNET(dyn_ack_lifetime) 153#define V_dyn_syn_lifetime VNET(dyn_syn_lifetime) 154#define V_dyn_fin_lifetime VNET(dyn_fin_lifetime) 155#define V_dyn_rst_lifetime VNET(dyn_rst_lifetime) 156#define V_dyn_udp_lifetime VNET(dyn_udp_lifetime) 157#define V_dyn_short_lifetime VNET(dyn_short_lifetime) 158 159/* 160 * Keepalives are sent if dyn_keepalive is set. They are sent every 161 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 162 * seconds of lifetime of a rule. 163 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 164 * than dyn_keepalive_period. 165 */ 166 167static VNET_DEFINE(u_int32_t, dyn_keepalive_interval); 168static VNET_DEFINE(u_int32_t, dyn_keepalive_period); 169static VNET_DEFINE(u_int32_t, dyn_keepalive); 170static VNET_DEFINE(time_t, dyn_keepalive_last); 171 172#define V_dyn_keepalive_interval VNET(dyn_keepalive_interval) 173#define V_dyn_keepalive_period VNET(dyn_keepalive_period) 174#define V_dyn_keepalive VNET(dyn_keepalive) 175#define V_dyn_keepalive_last VNET(dyn_keepalive_last) 176 177static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */ 178 179#define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone) 180#define V_dyn_max VNET(dyn_max) 181 182static int last_log; /* Log ratelimiting */ 183 184static void ipfw_dyn_tick(void *vnetx); 185static void check_dyn_rules(struct ip_fw_chain *, struct ip_fw *, 186 int, int, int); 187#ifdef SYSCTL_NODE 188 189static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS); 190static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS); 191 192SYSBEGIN(f2) 193 194SYSCTL_DECL(_net_inet_ip_fw); 195SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, 196 CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0, 197 "Max number of dyn. buckets"); 198SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, 199 CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0, 200 "Current Number of dyn. buckets"); 201SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count, 202 CTLTYPE_UINT|CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU", 203 "Number of dyn. rules"); 204SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max, 205 CTLTYPE_UINT|CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU", 206 "Max number of dyn. rules"); 207SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, 208 CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0, 209 "Lifetime of dyn. rules for acks"); 210SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, 211 CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0, 212 "Lifetime of dyn. rules for syn"); 213SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, 214 CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0, 215 "Lifetime of dyn. rules for fin"); 216SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, 217 CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0, 218 "Lifetime of dyn. rules for rst"); 219SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, 220 CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0, 221 "Lifetime of dyn. rules for UDP"); 222SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, 223 CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0, 224 "Lifetime of dyn. rules for other situations"); 225SYSCTL_VNET_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, 226 CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0, 227 "Enable keepalives for dyn. rules"); 228 229SYSEND 230 231#endif /* SYSCTL_NODE */ 232 233 234#ifdef INET6 235static __inline int 236hash_packet6(struct ipfw_flow_id *id) 237{ 238 u_int32_t i; 239 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 240 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 241 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 242 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^ 243 (id->dst_port) ^ (id->src_port); 244 return i; 245} 246#endif 247 248/* 249 * IMPORTANT: the hash function for dynamic rules must be commutative 250 * in source and destination (ip,port), because rules are bidirectional 251 * and we want to find both in the same bucket. 252 */ 253static __inline int 254hash_packet(struct ipfw_flow_id *id, int buckets) 255{ 256 u_int32_t i; 257 258#ifdef INET6 259 if (IS_IP6_FLOW_ID(id)) 260 i = hash_packet6(id); 261 else 262#endif /* INET6 */ 263 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 264 i &= (buckets - 1); 265 return i; 266} 267 268/** 269 * Print customizable flow id description via log(9) facility. 270 */ 271static void 272print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags, 273 char *prefix, char *postfix) 274{ 275 struct in_addr da; 276#ifdef INET6 277 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 278#else 279 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 280#endif 281 282#ifdef INET6 283 if (IS_IP6_FLOW_ID(id)) { 284 ip6_sprintf(src, &id->src_ip6); 285 ip6_sprintf(dst, &id->dst_ip6); 286 } else 287#endif 288 { 289 da.s_addr = htonl(id->src_ip); 290 inet_ntop(AF_INET, &da, src, sizeof(src)); 291 da.s_addr = htonl(id->dst_ip); 292 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 293 } 294 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 295 prefix, dyn_type, src, id->src_port, dst, 296 id->dst_port, DYN_COUNT, postfix); 297} 298 299#define print_dyn_rule(id, dtype, prefix, postfix) \ 300 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 301 302#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 303 304/* 305 * Lookup a dynamic rule, locked version. 306 */ 307static ipfw_dyn_rule * 308lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction, 309 struct tcphdr *tcp) 310{ 311 /* 312 * Stateful ipfw extensions. 313 * Lookup into dynamic session queue. 314 */ 315#define MATCH_REVERSE 0 316#define MATCH_FORWARD 1 317#define MATCH_NONE 2 318#define MATCH_UNKNOWN 3 319 int dir = MATCH_NONE; 320 ipfw_dyn_rule *prev, *q = NULL; 321 322 IPFW_BUCK_ASSERT(i); 323 324 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 325 if (q->dyn_type == O_LIMIT_PARENT && q->count) 326 continue; 327 328 if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT) 329 continue; 330 331 if (IS_IP6_FLOW_ID(pkt)) { 332 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 333 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 334 pkt->src_port == q->id.src_port && 335 pkt->dst_port == q->id.dst_port) { 336 dir = MATCH_FORWARD; 337 break; 338 } 339 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 340 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 341 pkt->src_port == q->id.dst_port && 342 pkt->dst_port == q->id.src_port) { 343 dir = MATCH_REVERSE; 344 break; 345 } 346 } else { 347 if (pkt->src_ip == q->id.src_ip && 348 pkt->dst_ip == q->id.dst_ip && 349 pkt->src_port == q->id.src_port && 350 pkt->dst_port == q->id.dst_port) { 351 dir = MATCH_FORWARD; 352 break; 353 } 354 if (pkt->src_ip == q->id.dst_ip && 355 pkt->dst_ip == q->id.src_ip && 356 pkt->src_port == q->id.dst_port && 357 pkt->dst_port == q->id.src_port) { 358 dir = MATCH_REVERSE; 359 break; 360 } 361 } 362 } 363 if (q == NULL) 364 goto done; /* q = NULL, not found */ 365 366 if (prev != NULL) { /* found and not in front */ 367 prev->next = q->next; 368 q->next = V_ipfw_dyn_v[i].head; 369 V_ipfw_dyn_v[i].head = q; 370 } 371 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 372 uint32_t ack; 373 u_char flags = pkt->_flags & (TH_FIN | TH_SYN | TH_RST); 374 375#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 376#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 377#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 378#define ACK_FWD 0x10000 /* fwd ack seen */ 379#define ACK_REV 0x20000 /* rev ack seen */ 380 381 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 382 switch (q->state & TCP_FLAGS) { 383 case TH_SYN: /* opening */ 384 q->expire = time_uptime + V_dyn_syn_lifetime; 385 break; 386 387 case BOTH_SYN: /* move to established */ 388 case BOTH_SYN | TH_FIN: /* one side tries to close */ 389 case BOTH_SYN | (TH_FIN << 8): 390#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 391 if (tcp == NULL) 392 break; 393 394 ack = ntohl(tcp->th_ack); 395 if (dir == MATCH_FORWARD) { 396 if (q->ack_fwd == 0 || 397 _SEQ_GE(ack, q->ack_fwd)) { 398 q->ack_fwd = ack; 399 q->state |= ACK_FWD; 400 } 401 } else { 402 if (q->ack_rev == 0 || 403 _SEQ_GE(ack, q->ack_rev)) { 404 q->ack_rev = ack; 405 q->state |= ACK_REV; 406 } 407 } 408 if ((q->state & (ACK_FWD | ACK_REV)) == 409 (ACK_FWD | ACK_REV)) { 410 q->expire = time_uptime + V_dyn_ack_lifetime; 411 q->state &= ~(ACK_FWD | ACK_REV); 412 } 413 break; 414 415 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 416 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 417 V_dyn_fin_lifetime = V_dyn_keepalive_period - 1; 418 q->expire = time_uptime + V_dyn_fin_lifetime; 419 break; 420 421 default: 422#if 0 423 /* 424 * reset or some invalid combination, but can also 425 * occur if we use keep-state the wrong way. 426 */ 427 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 428 printf("invalid state: 0x%x\n", q->state); 429#endif 430 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 431 V_dyn_rst_lifetime = V_dyn_keepalive_period - 1; 432 q->expire = time_uptime + V_dyn_rst_lifetime; 433 break; 434 } 435 } else if (pkt->proto == IPPROTO_UDP) { 436 q->expire = time_uptime + V_dyn_udp_lifetime; 437 } else { 438 /* other protocols */ 439 q->expire = time_uptime + V_dyn_short_lifetime; 440 } 441done: 442 if (match_direction != NULL) 443 *match_direction = dir; 444 return (q); 445} 446 447ipfw_dyn_rule * 448ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 449 struct tcphdr *tcp) 450{ 451 ipfw_dyn_rule *q; 452 int i; 453 454 i = hash_packet(pkt, V_curr_dyn_buckets); 455 456 IPFW_BUCK_LOCK(i); 457 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp); 458 if (q == NULL) 459 IPFW_BUCK_UNLOCK(i); 460 /* NB: return table locked when q is not NULL */ 461 return q; 462} 463 464/* 465 * Unlock bucket mtx 466 * @p - pointer to dynamic rule 467 */ 468void 469ipfw_dyn_unlock(ipfw_dyn_rule *q) 470{ 471 472 IPFW_BUCK_UNLOCK(q->bucket); 473} 474 475static int 476resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 477{ 478 int i, k, nbuckets_old; 479 ipfw_dyn_rule *q; 480 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 481 482 /* Check if given number is power of 2 and less than 64k */ 483 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 484 return 1; 485 486 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 487 V_curr_dyn_buckets, nbuckets); 488 489 /* Allocate and initialize new hash */ 490 dyn_v = malloc(nbuckets * sizeof(*dyn_v), M_IPFW, 491 M_WAITOK | M_ZERO); 492 493 for (i = 0 ; i < nbuckets; i++) 494 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 495 496 /* 497 * Call upper half lock, as get_map() do to ease 498 * read-only access to dynamic rules hash from sysctl 499 */ 500 IPFW_UH_WLOCK(chain); 501 502 /* 503 * Acquire chain write lock to permit hash access 504 * for main traffic path without additional locks 505 */ 506 IPFW_WLOCK(chain); 507 508 /* Save old values */ 509 nbuckets_old = V_curr_dyn_buckets; 510 dyn_v_old = V_ipfw_dyn_v; 511 512 /* Skip relinking if array is not set up */ 513 if (V_ipfw_dyn_v == NULL) 514 V_curr_dyn_buckets = 0; 515 516 /* Re-link all dynamic states */ 517 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 518 while (V_ipfw_dyn_v[i].head != NULL) { 519 /* Remove from current chain */ 520 q = V_ipfw_dyn_v[i].head; 521 V_ipfw_dyn_v[i].head = q->next; 522 523 /* Get new hash value */ 524 k = hash_packet(&q->id, nbuckets); 525 q->bucket = k; 526 /* Add to the new head */ 527 q->next = dyn_v[k].head; 528 dyn_v[k].head = q; 529 } 530 } 531 532 /* Update current pointers/buckets values */ 533 V_curr_dyn_buckets = nbuckets; 534 V_ipfw_dyn_v = dyn_v; 535 536 IPFW_WUNLOCK(chain); 537 538 IPFW_UH_WUNLOCK(chain); 539 540 /* Start periodic callout on initial creation */ 541 if (dyn_v_old == NULL) { 542 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 543 return (0); 544 } 545 546 /* Destroy all mutexes */ 547 for (i = 0 ; i < nbuckets_old ; i++) 548 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 549 550 /* Free old hash */ 551 free(dyn_v_old, M_IPFW); 552 553 return 0; 554} 555 556/** 557 * Install state of type 'type' for a dynamic session. 558 * The hash table contains two type of rules: 559 * - regular rules (O_KEEP_STATE) 560 * - rules for sessions with limited number of sess per user 561 * (O_LIMIT). When they are created, the parent is 562 * increased by 1, and decreased on delete. In this case, 563 * the third parameter is the parent rule and not the chain. 564 * - "parent" rules for the above (O_LIMIT_PARENT). 565 */ 566static ipfw_dyn_rule * 567add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule) 568{ 569 ipfw_dyn_rule *r; 570 571 IPFW_BUCK_ASSERT(i); 572 573 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 574 if (r == NULL) { 575 if (last_log != time_uptime) { 576 last_log = time_uptime; 577 log(LOG_DEBUG, "ipfw: %s: Cannot allocate rule\n", 578 __func__); 579 } 580 return NULL; 581 } 582 583 /* 584 * refcount on parent is already incremented, so 585 * it is safe to use parent unlocked. 586 */ 587 if (dyn_type == O_LIMIT) { 588 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 589 if ( parent->dyn_type != O_LIMIT_PARENT) 590 panic("invalid parent"); 591 r->parent = parent; 592 rule = parent->rule; 593 } 594 595 r->id = *id; 596 r->expire = time_uptime + V_dyn_syn_lifetime; 597 r->rule = rule; 598 r->dyn_type = dyn_type; 599 IPFW_ZERO_DYN_COUNTER(r); 600 r->count = 0; 601 602 r->bucket = i; 603 r->next = V_ipfw_dyn_v[i].head; 604 V_ipfw_dyn_v[i].head = r; 605 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 606 return r; 607} 608 609/** 610 * lookup dynamic parent rule using pkt and rule as search keys. 611 * If the lookup fails, then install one. 612 */ 613static ipfw_dyn_rule * 614lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule) 615{ 616 ipfw_dyn_rule *q; 617 int i, is_v6; 618 619 is_v6 = IS_IP6_FLOW_ID(pkt); 620 i = hash_packet( pkt, V_curr_dyn_buckets ); 621 *pindex = i; 622 IPFW_BUCK_LOCK(i); 623 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 624 if (q->dyn_type == O_LIMIT_PARENT && 625 rule== q->rule && 626 pkt->proto == q->id.proto && 627 pkt->src_port == q->id.src_port && 628 pkt->dst_port == q->id.dst_port && 629 ( 630 (is_v6 && 631 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 632 &(q->id.src_ip6)) && 633 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 634 &(q->id.dst_ip6))) || 635 (!is_v6 && 636 pkt->src_ip == q->id.src_ip && 637 pkt->dst_ip == q->id.dst_ip) 638 ) 639 ) { 640 q->expire = time_uptime + V_dyn_short_lifetime; 641 DEB(print_dyn_rule(pkt, q->dyn_type, 642 "lookup_dyn_parent found", "");) 643 return q; 644 } 645 646 /* Add virtual limiting rule */ 647 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule); 648} 649 650/** 651 * Install dynamic state for rule type cmd->o.opcode 652 * 653 * Returns 1 (failure) if state is not installed because of errors or because 654 * session limitations are enforced. 655 */ 656int 657ipfw_install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 658 struct ip_fw_args *args, uint32_t tablearg) 659{ 660 ipfw_dyn_rule *q; 661 int i; 662 663 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");) 664 665 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 666 667 IPFW_BUCK_LOCK(i); 668 669 q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 670 671 if (q != NULL) { /* should never occur */ 672 DEB( 673 if (last_log != time_uptime) { 674 last_log = time_uptime; 675 printf("ipfw: %s: entry already present, done\n", 676 __func__); 677 }) 678 IPFW_BUCK_UNLOCK(i); 679 return (0); 680 } 681 682 /* 683 * State limiting is done via uma(9) zone limiting. 684 * Save pointer to newly-installed rule and reject 685 * packet if add_dyn_rule() returned NULL. 686 * Note q is currently set to NULL. 687 */ 688 689 switch (cmd->o.opcode) { 690 case O_KEEP_STATE: /* bidir rule */ 691 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule); 692 break; 693 694 case O_LIMIT: { /* limit number of sessions */ 695 struct ipfw_flow_id id; 696 ipfw_dyn_rule *parent; 697 uint32_t conn_limit; 698 uint16_t limit_mask = cmd->limit_mask; 699 int pindex; 700 701 conn_limit = IP_FW_ARG_TABLEARG(cmd->conn_limit); 702 703 DEB( 704 if (cmd->conn_limit == IP_FW_TABLEARG) 705 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 706 "(tablearg)\n", __func__, conn_limit); 707 else 708 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 709 __func__, conn_limit); 710 ) 711 712 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 713 id.proto = args->f_id.proto; 714 id.addr_type = args->f_id.addr_type; 715 id.fib = M_GETFIB(args->m); 716 717 if (IS_IP6_FLOW_ID (&(args->f_id))) { 718 bzero(&id.src_ip6, sizeof(id.src_ip6)); 719 bzero(&id.dst_ip6, sizeof(id.dst_ip6)); 720 721 if (limit_mask & DYN_SRC_ADDR) 722 id.src_ip6 = args->f_id.src_ip6; 723 if (limit_mask & DYN_DST_ADDR) 724 id.dst_ip6 = args->f_id.dst_ip6; 725 } else { 726 if (limit_mask & DYN_SRC_ADDR) 727 id.src_ip = args->f_id.src_ip; 728 if (limit_mask & DYN_DST_ADDR) 729 id.dst_ip = args->f_id.dst_ip; 730 } 731 if (limit_mask & DYN_SRC_PORT) 732 id.src_port = args->f_id.src_port; 733 if (limit_mask & DYN_DST_PORT) 734 id.dst_port = args->f_id.dst_port; 735 736 /* 737 * We have to release lock for previous bucket to 738 * avoid possible deadlock 739 */ 740 IPFW_BUCK_UNLOCK(i); 741 742 if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) { 743 printf("ipfw: %s: add parent failed\n", __func__); 744 IPFW_BUCK_UNLOCK(pindex); 745 return (1); 746 } 747 748 if (parent->count >= conn_limit) { 749 if (V_fw_verbose && last_log != time_uptime) { 750 last_log = time_uptime; 751 char sbuf[24]; 752 last_log = time_uptime; 753 snprintf(sbuf, sizeof(sbuf), 754 "%d drop session", 755 parent->rule->rulenum); 756 print_dyn_rule_flags(&args->f_id, 757 cmd->o.opcode, 758 LOG_SECURITY | LOG_DEBUG, 759 sbuf, "too many entries"); 760 } 761 IPFW_BUCK_UNLOCK(pindex); 762 return (1); 763 } 764 /* Increment counter on parent */ 765 parent->count++; 766 IPFW_BUCK_UNLOCK(pindex); 767 768 IPFW_BUCK_LOCK(i); 769 q = add_dyn_rule(&args->f_id, i, O_LIMIT, (struct ip_fw *)parent); 770 if (q == NULL) { 771 /* Decrement index and notify caller */ 772 IPFW_BUCK_UNLOCK(i); 773 IPFW_BUCK_LOCK(pindex); 774 parent->count--; 775 IPFW_BUCK_UNLOCK(pindex); 776 return (1); 777 } 778 break; 779 } 780 default: 781 printf("ipfw: %s: unknown dynamic rule type %u\n", 782 __func__, cmd->o.opcode); 783 } 784 785 if (q == NULL) { 786 IPFW_BUCK_UNLOCK(i); 787 return (1); /* Notify caller about failure */ 788 } 789 790 /* XXX just set lifetime */ 791 lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 792 793 IPFW_BUCK_UNLOCK(i); 794 return (0); 795} 796 797/* 798 * Generate a TCP packet, containing either a RST or a keepalive. 799 * When flags & TH_RST, we are sending a RST packet, because of a 800 * "reset" action matched the packet. 801 * Otherwise we are sending a keepalive, and flags & TH_ 802 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 803 * so that MAC can label the reply appropriately. 804 */ 805struct mbuf * 806ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 807 u_int32_t ack, int flags) 808{ 809 struct mbuf *m = NULL; /* stupid compiler */ 810 int len, dir; 811 struct ip *h = NULL; /* stupid compiler */ 812#ifdef INET6 813 struct ip6_hdr *h6 = NULL; 814#endif 815 struct tcphdr *th = NULL; 816 817 MGETHDR(m, M_NOWAIT, MT_DATA); 818 if (m == NULL) 819 return (NULL); 820 821 M_SETFIB(m, id->fib); 822#ifdef MAC 823 if (replyto != NULL) 824 mac_netinet_firewall_reply(replyto, m); 825 else 826 mac_netinet_firewall_send(m); 827#else 828 (void)replyto; /* don't warn about unused arg */ 829#endif 830 831 switch (id->addr_type) { 832 case 4: 833 len = sizeof(struct ip) + sizeof(struct tcphdr); 834 break; 835#ifdef INET6 836 case 6: 837 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 838 break; 839#endif 840 default: 841 /* XXX: log me?!? */ 842 FREE_PKT(m); 843 return (NULL); 844 } 845 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 846 847 m->m_data += max_linkhdr; 848 m->m_flags |= M_SKIP_FIREWALL; 849 m->m_pkthdr.len = m->m_len = len; 850 m->m_pkthdr.rcvif = NULL; 851 bzero(m->m_data, len); 852 853 switch (id->addr_type) { 854 case 4: 855 h = mtod(m, struct ip *); 856 857 /* prepare for checksum */ 858 h->ip_p = IPPROTO_TCP; 859 h->ip_len = htons(sizeof(struct tcphdr)); 860 if (dir) { 861 h->ip_src.s_addr = htonl(id->src_ip); 862 h->ip_dst.s_addr = htonl(id->dst_ip); 863 } else { 864 h->ip_src.s_addr = htonl(id->dst_ip); 865 h->ip_dst.s_addr = htonl(id->src_ip); 866 } 867 868 th = (struct tcphdr *)(h + 1); 869 break; 870#ifdef INET6 871 case 6: 872 h6 = mtod(m, struct ip6_hdr *); 873 874 /* prepare for checksum */ 875 h6->ip6_nxt = IPPROTO_TCP; 876 h6->ip6_plen = htons(sizeof(struct tcphdr)); 877 if (dir) { 878 h6->ip6_src = id->src_ip6; 879 h6->ip6_dst = id->dst_ip6; 880 } else { 881 h6->ip6_src = id->dst_ip6; 882 h6->ip6_dst = id->src_ip6; 883 } 884 885 th = (struct tcphdr *)(h6 + 1); 886 break; 887#endif 888 } 889 890 if (dir) { 891 th->th_sport = htons(id->src_port); 892 th->th_dport = htons(id->dst_port); 893 } else { 894 th->th_sport = htons(id->dst_port); 895 th->th_dport = htons(id->src_port); 896 } 897 th->th_off = sizeof(struct tcphdr) >> 2; 898 899 if (flags & TH_RST) { 900 if (flags & TH_ACK) { 901 th->th_seq = htonl(ack); 902 th->th_flags = TH_RST; 903 } else { 904 if (flags & TH_SYN) 905 seq++; 906 th->th_ack = htonl(seq); 907 th->th_flags = TH_RST | TH_ACK; 908 } 909 } else { 910 /* 911 * Keepalive - use caller provided sequence numbers 912 */ 913 th->th_seq = htonl(seq); 914 th->th_ack = htonl(ack); 915 th->th_flags = TH_ACK; 916 } 917 918 switch (id->addr_type) { 919 case 4: 920 th->th_sum = in_cksum(m, len); 921 922 /* finish the ip header */ 923 h->ip_v = 4; 924 h->ip_hl = sizeof(*h) >> 2; 925 h->ip_tos = IPTOS_LOWDELAY; 926 h->ip_off = htons(0); 927 h->ip_len = htons(len); 928 h->ip_ttl = V_ip_defttl; 929 h->ip_sum = 0; 930 break; 931#ifdef INET6 932 case 6: 933 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 934 sizeof(struct tcphdr)); 935 936 /* finish the ip6 header */ 937 h6->ip6_vfc |= IPV6_VERSION; 938 h6->ip6_hlim = IPV6_DEFHLIM; 939 break; 940#endif 941 } 942 943 return (m); 944} 945 946/* 947 * Queue keepalive packets for given dynamic rule 948 */ 949static struct mbuf ** 950ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 951{ 952 struct mbuf *m_rev, *m_fwd; 953 954 m_rev = (q->state & ACK_REV) ? NULL : 955 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 956 m_fwd = (q->state & ACK_FWD) ? NULL : 957 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 958 959 if (m_rev != NULL) { 960 *mtailp = m_rev; 961 mtailp = &(*mtailp)->m_nextpkt; 962 } 963 if (m_fwd != NULL) { 964 *mtailp = m_fwd; 965 mtailp = &(*mtailp)->m_nextpkt; 966 } 967 968 return (mtailp); 969} 970 971/* 972 * This procedure is used to perform various maintance 973 * on dynamic hash list. Currently it is called every second. 974 */ 975static void 976ipfw_dyn_tick(void * vnetx) 977{ 978 struct ip_fw_chain *chain; 979 int check_ka = 0; 980#ifdef VIMAGE 981 struct vnet *vp = vnetx; 982#endif 983 984 CURVNET_SET(vp); 985 986 chain = &V_layer3_chain; 987 988 /* Run keepalive checks every keepalive_period iff ka is enabled */ 989 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 990 (V_dyn_keepalive != 0)) { 991 V_dyn_keepalive_last = time_uptime; 992 check_ka = 1; 993 } 994 995 check_dyn_rules(chain, NULL, RESVD_SET, check_ka, 1); 996 997 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 998 999 CURVNET_RESTORE(); 1000} 1001 1002 1003/* 1004 * Walk thru all dynamic states doing generic maintance: 1005 * 1) free expired states 1006 * 2) free all states based on deleted rule / set 1007 * 3) send keepalives for states if needed 1008 * 1009 * @chain - pointer to current ipfw rules chain 1010 * @rule - delete all states originated by given rule if != NULL 1011 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1012 * @check_ka - perform checking/sending keepalives 1013 * @timer - indicate call from timer routine. 1014 * 1015 * Timer routine must call this function unlocked to permit 1016 * sending keepalives/resizing table. 1017 * 1018 * Others has to call function with IPFW_UH_WLOCK held. 1019 * Additionally, function assume that dynamic rule/set is 1020 * ALREADY deleted so no new states can be generated by 1021 * 'deleted' rules. 1022 * 1023 * Write lock is needed to ensure that unused parent rules 1024 * are not freed by other instance (see stage 2, 3) 1025 */ 1026static void 1027check_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, 1028 int set, int check_ka, int timer) 1029{ 1030 struct mbuf *m0, *m, *mnext, **mtailp; 1031 struct ip *h; 1032 int i, dyn_count, new_buckets = 0, max_buckets; 1033 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1034 ipfw_dyn_rule *q, *q_prev, *q_next; 1035 ipfw_dyn_rule *exp_head, **exptailp; 1036 ipfw_dyn_rule *exp_lhead, **expltailp; 1037 1038 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1039 __func__)); 1040 1041 /* Avoid possible LOR */ 1042 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1043 __func__)); 1044 1045 /* 1046 * Do not perform any checks if we currently have no dynamic states 1047 */ 1048 if (DYN_COUNT == 0) 1049 return; 1050 1051 /* Expired states */ 1052 exp_head = NULL; 1053 exptailp = &exp_head; 1054 1055 /* Expired limit states */ 1056 exp_lhead = NULL; 1057 expltailp = &exp_lhead; 1058 1059 /* 1060 * We make a chain of packets to go out here -- not deferring 1061 * until after we drop the IPFW dynamic rule lock would result 1062 * in a lock order reversal with the normal packet input -> ipfw 1063 * call stack. 1064 */ 1065 m0 = NULL; 1066 mtailp = &m0; 1067 1068 /* Protect from hash resizing */ 1069 if (timer != 0) 1070 IPFW_UH_WLOCK(chain); 1071 else 1072 IPFW_UH_WLOCK_ASSERT(chain); 1073 1074#define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1075 1076 /* Stage 1: perform requested deletion */ 1077 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1078 IPFW_BUCK_LOCK(i); 1079 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1080 /* account every rule */ 1081 total++; 1082 1083 /* Skip parent rules at all */ 1084 if (q->dyn_type == O_LIMIT_PARENT) { 1085 parents++; 1086 NEXT_RULE(); 1087 } 1088 1089 /* 1090 * Remove rules which are: 1091 * 1) expired 1092 * 2) created by given rule 1093 * 3) created by any rule in given set 1094 */ 1095 if ((TIME_LEQ(q->expire, time_uptime)) || 1096 ((rule != NULL) && (q->rule == rule)) || 1097 ((set != RESVD_SET) && (q->rule->set == set))) { 1098 /* Unlink q from current list */ 1099 q_next = q->next; 1100 if (q == V_ipfw_dyn_v[i].head) 1101 V_ipfw_dyn_v[i].head = q_next; 1102 else 1103 q_prev->next = q_next; 1104 1105 q->next = NULL; 1106 1107 /* queue q to expire list */ 1108 if (q->dyn_type != O_LIMIT) { 1109 *exptailp = q; 1110 exptailp = &(*exptailp)->next; 1111 DEB(print_dyn_rule(&q->id, q->dyn_type, 1112 "unlink entry", "left"); 1113 ) 1114 } else { 1115 /* Separate list for limit rules */ 1116 *expltailp = q; 1117 expltailp = &(*expltailp)->next; 1118 expired_limits++; 1119 DEB(print_dyn_rule(&q->id, q->dyn_type, 1120 "unlink limit entry", "left"); 1121 ) 1122 } 1123 1124 q = q_next; 1125 expired++; 1126 continue; 1127 } 1128 1129 /* 1130 * Check if we need to send keepalive: 1131 * we need to ensure if is time to do KA, 1132 * this is established TCP session, and 1133 * expire time is within keepalive interval 1134 */ 1135 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1136 ((q->state & BOTH_SYN) == BOTH_SYN) && 1137 (TIME_LEQ(q->expire, time_uptime + 1138 V_dyn_keepalive_interval))) 1139 mtailp = ipfw_dyn_send_ka(mtailp, q); 1140 1141 NEXT_RULE(); 1142 } 1143 IPFW_BUCK_UNLOCK(i); 1144 } 1145 1146 /* Stage 2: decrement counters from O_LIMIT parents */ 1147 if (expired_limits != 0) { 1148 /* 1149 * XXX: Note that deleting set with more than one 1150 * heavily-used LIMIT rules can result in overwhelming 1151 * locking due to lack of per-hash value sorting 1152 * 1153 * We should probably think about: 1154 * 1) pre-allocating hash of size, say, 1155 * MAX(16, V_curr_dyn_buckets / 1024) 1156 * 2) checking if expired_limits is large enough 1157 * 3) If yes, init hash (or its part), re-link 1158 * current list and start decrementing procedure in 1159 * each bucket separately 1160 */ 1161 1162 /* 1163 * Small optimization: do not unlock bucket until 1164 * we see the next item resides in different bucket 1165 */ 1166 if (exp_lhead != NULL) { 1167 i = exp_lhead->parent->bucket; 1168 IPFW_BUCK_LOCK(i); 1169 } 1170 for (q = exp_lhead; q != NULL; q = q->next) { 1171 if (i != q->parent->bucket) { 1172 IPFW_BUCK_UNLOCK(i); 1173 i = q->parent->bucket; 1174 IPFW_BUCK_LOCK(i); 1175 } 1176 1177 /* Decrease parent refcount */ 1178 q->parent->count--; 1179 } 1180 if (exp_lhead != NULL) 1181 IPFW_BUCK_UNLOCK(i); 1182 } 1183 1184 /* 1185 * We protectet ourselves from unused parent deletion 1186 * (from the timer function) by holding UH write lock. 1187 */ 1188 1189 /* Stage 3: remove unused parent rules */ 1190 if ((parents != 0) && (expired != 0)) { 1191 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1192 IPFW_BUCK_LOCK(i); 1193 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1194 if (q->dyn_type != O_LIMIT_PARENT) 1195 NEXT_RULE(); 1196 1197 if (q->count != 0) 1198 NEXT_RULE(); 1199 1200 /* Parent rule without consumers */ 1201 1202 /* Unlink q from current list */ 1203 q_next = q->next; 1204 if (q == V_ipfw_dyn_v[i].head) 1205 V_ipfw_dyn_v[i].head = q_next; 1206 else 1207 q_prev->next = q_next; 1208 1209 q->next = NULL; 1210 1211 /* Add to expired list */ 1212 *exptailp = q; 1213 exptailp = &(*exptailp)->next; 1214 1215 DEB(print_dyn_rule(&q->id, q->dyn_type, 1216 "unlink parent entry", "left"); 1217 ) 1218 1219 expired++; 1220 1221 q = q_next; 1222 } 1223 IPFW_BUCK_UNLOCK(i); 1224 } 1225 } 1226 1227#undef NEXT_RULE 1228 1229 if (timer != 0) { 1230 /* 1231 * Check if we need to resize hash: 1232 * if current number of states exceeds number of buckes in hash, 1233 * grow hash size to the minimum power of 2 which is bigger than 1234 * current states count. Limit hash size by 64k. 1235 */ 1236 max_buckets = (V_dyn_buckets_max > 65536) ? 1237 65536 : V_dyn_buckets_max; 1238 1239 dyn_count = DYN_COUNT; 1240 1241 if ((dyn_count > V_curr_dyn_buckets * 2) && 1242 (dyn_count < max_buckets)) { 1243 new_buckets = V_curr_dyn_buckets; 1244 while (new_buckets < dyn_count) { 1245 new_buckets *= 2; 1246 1247 if (new_buckets >= max_buckets) 1248 break; 1249 } 1250 } 1251 1252 IPFW_UH_WUNLOCK(chain); 1253 } 1254 1255 /* Finally delete old states ad limits if any */ 1256 for (q = exp_head; q != NULL; q = q_next) { 1257 q_next = q->next; 1258 uma_zfree(V_ipfw_dyn_rule_zone, q); 1259 } 1260 1261 for (q = exp_lhead; q != NULL; q = q_next) { 1262 q_next = q->next; 1263 uma_zfree(V_ipfw_dyn_rule_zone, q); 1264 } 1265 1266 /* 1267 * The rest code MUST be called from timer routine only 1268 * without holding any locks 1269 */ 1270 if (timer == 0) 1271 return; 1272 1273 /* Send keepalive packets if any */ 1274 for (m = m0; m != NULL; m = mnext) { 1275 mnext = m->m_nextpkt; 1276 m->m_nextpkt = NULL; 1277 h = mtod(m, struct ip *); 1278 if (h->ip_v == 4) 1279 ip_output(m, NULL, NULL, 0, NULL, NULL); 1280#ifdef INET6 1281 else 1282 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1283#endif 1284 } 1285 1286 /* Run table resize without holding any locks */ 1287 if (new_buckets != 0) 1288 resize_dynamic_table(chain, new_buckets); 1289} 1290 1291/* 1292 * Deletes all dynamic rules originated by given rule or all rules in 1293 * given set. Specify RESVD_SET to indicate set should not be used. 1294 * @chain - pointer to current ipfw rules chain 1295 * @rule - delete all states originated by given rule if != NULL 1296 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1297 * 1298 * Function has to be called with IPFW_UH_WLOCK held. 1299 * Additionally, function assume that dynamic rule/set is 1300 * ALREADY deleted so no new states can be generated by 1301 * 'deleted' rules. 1302 */ 1303void 1304ipfw_expire_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, int set) 1305{ 1306 1307 check_dyn_rules(chain, rule, set, 0, 0); 1308} 1309 1310void 1311ipfw_dyn_init(struct ip_fw_chain *chain) 1312{ 1313 1314 V_ipfw_dyn_v = NULL; 1315 V_dyn_buckets_max = 256; /* must be power of 2 */ 1316 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1317 1318 V_dyn_ack_lifetime = 300; 1319 V_dyn_syn_lifetime = 20; 1320 V_dyn_fin_lifetime = 1; 1321 V_dyn_rst_lifetime = 1; 1322 V_dyn_udp_lifetime = 10; 1323 V_dyn_short_lifetime = 5; 1324 1325 V_dyn_keepalive_interval = 20; 1326 V_dyn_keepalive_period = 5; 1327 V_dyn_keepalive = 1; /* do send keepalives */ 1328 V_dyn_keepalive_last = time_uptime; 1329 1330 V_dyn_max = 4096; /* max # of dynamic rules */ 1331 1332 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1333 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1334 UMA_ALIGN_PTR, 0); 1335 1336 /* Enforce limit on dynamic rules */ 1337 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1338 1339 callout_init(&V_ipfw_timeout, 1); 1340 1341 /* 1342 * This can potentially be done on first dynamic rule 1343 * being added to chain. 1344 */ 1345 resize_dynamic_table(chain, V_curr_dyn_buckets); 1346} 1347 1348void 1349ipfw_dyn_uninit(int pass) 1350{ 1351 int i; 1352 1353 if (pass == 0) { 1354 callout_drain(&V_ipfw_timeout); 1355 return; 1356 } 1357 1358 if (V_ipfw_dyn_v != NULL) { 1359 /* 1360 * Skip deleting all dynamic states - 1361 * uma_zdestroy() does this more efficiently; 1362 */ 1363 1364 /* Destroy all mutexes */ 1365 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1366 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1367 free(V_ipfw_dyn_v, M_IPFW); 1368 V_ipfw_dyn_v = NULL; 1369 } 1370 1371 uma_zdestroy(V_ipfw_dyn_rule_zone); 1372} 1373 1374#ifdef SYSCTL_NODE 1375/* 1376 * Get/set maximum number of dynamic states in given VNET instance. 1377 */ 1378static int 1379sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1380{ 1381 int error; 1382 unsigned int nstates; 1383 1384 nstates = V_dyn_max; 1385 1386 error = sysctl_handle_int(oidp, &nstates, 0, req); 1387 /* Read operation or some error */ 1388 if ((error != 0) || (req->newptr == NULL)) 1389 return (error); 1390 1391 V_dyn_max = nstates; 1392 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1393 1394 return (0); 1395} 1396 1397/* 1398 * Get current number of dynamic states in given VNET instance. 1399 */ 1400static int 1401sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1402{ 1403 int error; 1404 unsigned int nstates; 1405 1406 nstates = DYN_COUNT; 1407 1408 error = sysctl_handle_int(oidp, &nstates, 0, req); 1409 1410 return (error); 1411} 1412#endif 1413 1414/* 1415 * Returns number of dynamic rules. 1416 */ 1417int 1418ipfw_dyn_len(void) 1419{ 1420 1421 return (V_ipfw_dyn_v == NULL) ? 0 : 1422 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1423} 1424 1425/* 1426 * Fill given buffer with dynamic states. 1427 * IPFW_UH_RLOCK has to be held while calling. 1428 */ 1429void 1430ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1431{ 1432 ipfw_dyn_rule *p, *last = NULL; 1433 char *bp; 1434 int i; 1435 1436 if (V_ipfw_dyn_v == NULL) 1437 return; 1438 bp = *pbp; 1439 1440 IPFW_UH_RLOCK_ASSERT(chain); 1441 1442 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1443 IPFW_BUCK_LOCK(i); 1444 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1445 if (bp + sizeof *p <= ep) { 1446 ipfw_dyn_rule *dst = 1447 (ipfw_dyn_rule *)bp; 1448 bcopy(p, dst, sizeof *p); 1449 bcopy(&(p->rule->rulenum), &(dst->rule), 1450 sizeof(p->rule->rulenum)); 1451 /* 1452 * store set number into high word of 1453 * dst->rule pointer. 1454 */ 1455 bcopy(&(p->rule->set), 1456 (char *)&dst->rule + 1457 sizeof(p->rule->rulenum), 1458 sizeof(p->rule->set)); 1459 /* 1460 * store a non-null value in "next". 1461 * The userland code will interpret a 1462 * NULL here as a marker 1463 * for the last dynamic rule. 1464 */ 1465 bcopy(&dst, &dst->next, sizeof(dst)); 1466 last = dst; 1467 dst->expire = 1468 TIME_LEQ(dst->expire, time_uptime) ? 1469 0 : dst->expire - time_uptime ; 1470 bp += sizeof(ipfw_dyn_rule); 1471 } 1472 } 1473 IPFW_BUCK_UNLOCK(i); 1474 } 1475 1476 if (last != NULL) /* mark last dynamic rule */ 1477 bzero(&last->next, sizeof(last)); 1478 *pbp = bp; 1479} 1480/* end of file */ 1481