ip_fw_dynamic.c revision 250760
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/9/sys/netpfil/ipfw/ip_fw_dynamic.c 250760 2013-05-18 05:31:17Z melifaro $"); 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 234static __inline int 235hash_packet6(struct ipfw_flow_id *id) 236{ 237 u_int32_t i; 238 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 239 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 240 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 241 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^ 242 (id->dst_port) ^ (id->src_port); 243 return i; 244} 245 246/* 247 * IMPORTANT: the hash function for dynamic rules must be commutative 248 * in source and destination (ip,port), because rules are bidirectional 249 * and we want to find both in the same bucket. 250 */ 251static __inline int 252hash_packet(struct ipfw_flow_id *id, int buckets) 253{ 254 u_int32_t i; 255 256#ifdef INET6 257 if (IS_IP6_FLOW_ID(id)) 258 i = hash_packet6(id); 259 else 260#endif /* INET6 */ 261 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port); 262 i &= (buckets - 1); 263 return i; 264} 265 266/** 267 * Print customizable flow id description via log(9) facility. 268 */ 269static void 270print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags, 271 char *prefix, char *postfix) 272{ 273 struct in_addr da; 274#ifdef INET6 275 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 276#else 277 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 278#endif 279 280#ifdef INET6 281 if (IS_IP6_FLOW_ID(id)) { 282 ip6_sprintf(src, &id->src_ip6); 283 ip6_sprintf(dst, &id->dst_ip6); 284 } else 285#endif 286 { 287 da.s_addr = htonl(id->src_ip); 288 inet_ntop(AF_INET, &da, src, sizeof(src)); 289 da.s_addr = htonl(id->dst_ip); 290 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 291 } 292 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 293 prefix, dyn_type, src, id->src_port, dst, 294 id->dst_port, DYN_COUNT, postfix); 295} 296 297#define print_dyn_rule(id, dtype, prefix, postfix) \ 298 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 299 300#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 301 302/* 303 * Lookup a dynamic rule, locked version. 304 */ 305static ipfw_dyn_rule * 306lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction, 307 struct tcphdr *tcp) 308{ 309 /* 310 * Stateful ipfw extensions. 311 * Lookup into dynamic session queue. 312 */ 313#define MATCH_REVERSE 0 314#define MATCH_FORWARD 1 315#define MATCH_NONE 2 316#define MATCH_UNKNOWN 3 317 int dir = MATCH_NONE; 318 ipfw_dyn_rule *prev, *q = NULL; 319 320 IPFW_BUCK_ASSERT(i); 321 322 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 323 if (q->dyn_type == O_LIMIT_PARENT && q->count) 324 continue; 325 326 if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT) 327 continue; 328 329 if (IS_IP6_FLOW_ID(pkt)) { 330 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 331 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 332 pkt->src_port == q->id.src_port && 333 pkt->dst_port == q->id.dst_port) { 334 dir = MATCH_FORWARD; 335 break; 336 } 337 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 338 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 339 pkt->src_port == q->id.dst_port && 340 pkt->dst_port == q->id.src_port) { 341 dir = MATCH_REVERSE; 342 break; 343 } 344 } else { 345 if (pkt->src_ip == q->id.src_ip && 346 pkt->dst_ip == q->id.dst_ip && 347 pkt->src_port == q->id.src_port && 348 pkt->dst_port == q->id.dst_port) { 349 dir = MATCH_FORWARD; 350 break; 351 } 352 if (pkt->src_ip == q->id.dst_ip && 353 pkt->dst_ip == q->id.src_ip && 354 pkt->src_port == q->id.dst_port && 355 pkt->dst_port == q->id.src_port) { 356 dir = MATCH_REVERSE; 357 break; 358 } 359 } 360 } 361 if (q == NULL) 362 goto done; /* q = NULL, not found */ 363 364 if (prev != NULL) { /* found and not in front */ 365 prev->next = q->next; 366 q->next = V_ipfw_dyn_v[i].head; 367 V_ipfw_dyn_v[i].head = q; 368 } 369 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */ 370 uint32_t ack; 371 u_char flags = pkt->_flags & (TH_FIN | TH_SYN | TH_RST); 372 373#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 374#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 375#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 376#define ACK_FWD 0x10000 /* fwd ack seen */ 377#define ACK_REV 0x20000 /* rev ack seen */ 378 379 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 380 switch (q->state & TCP_FLAGS) { 381 case TH_SYN: /* opening */ 382 q->expire = time_uptime + V_dyn_syn_lifetime; 383 break; 384 385 case BOTH_SYN: /* move to established */ 386 case BOTH_SYN | TH_FIN: /* one side tries to close */ 387 case BOTH_SYN | (TH_FIN << 8): 388#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 389 if (tcp == NULL) 390 break; 391 392 ack = ntohl(tcp->th_ack); 393 if (dir == MATCH_FORWARD) { 394 if (q->ack_fwd == 0 || 395 _SEQ_GE(ack, q->ack_fwd)) { 396 q->ack_fwd = ack; 397 q->state |= ACK_FWD; 398 } 399 } else { 400 if (q->ack_rev == 0 || 401 _SEQ_GE(ack, q->ack_rev)) { 402 q->ack_rev = ack; 403 q->state |= ACK_REV; 404 } 405 } 406 if ((q->state & (ACK_FWD | ACK_REV)) == 407 (ACK_FWD | ACK_REV)) { 408 q->expire = time_uptime + V_dyn_ack_lifetime; 409 q->state &= ~(ACK_FWD | ACK_REV); 410 } 411 break; 412 413 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 414 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 415 V_dyn_fin_lifetime = V_dyn_keepalive_period - 1; 416 q->expire = time_uptime + V_dyn_fin_lifetime; 417 break; 418 419 default: 420#if 0 421 /* 422 * reset or some invalid combination, but can also 423 * occur if we use keep-state the wrong way. 424 */ 425 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 426 printf("invalid state: 0x%x\n", q->state); 427#endif 428 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 429 V_dyn_rst_lifetime = V_dyn_keepalive_period - 1; 430 q->expire = time_uptime + V_dyn_rst_lifetime; 431 break; 432 } 433 } else if (pkt->proto == IPPROTO_UDP) { 434 q->expire = time_uptime + V_dyn_udp_lifetime; 435 } else { 436 /* other protocols */ 437 q->expire = time_uptime + V_dyn_short_lifetime; 438 } 439done: 440 if (match_direction != NULL) 441 *match_direction = dir; 442 return (q); 443} 444 445ipfw_dyn_rule * 446ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 447 struct tcphdr *tcp) 448{ 449 ipfw_dyn_rule *q; 450 int i; 451 452 i = hash_packet(pkt, V_curr_dyn_buckets); 453 454 IPFW_BUCK_LOCK(i); 455 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp); 456 if (q == NULL) 457 IPFW_BUCK_UNLOCK(i); 458 /* NB: return table locked when q is not NULL */ 459 return q; 460} 461 462/* 463 * Unlock bucket mtx 464 * @p - pointer to dynamic rule 465 */ 466void 467ipfw_dyn_unlock(ipfw_dyn_rule *q) 468{ 469 470 IPFW_BUCK_UNLOCK(q->bucket); 471} 472 473static int 474resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 475{ 476 int i, k, nbuckets_old; 477 ipfw_dyn_rule *q; 478 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 479 480 /* Check if given number is power of 2 and less than 64k */ 481 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 482 return 1; 483 484 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 485 V_curr_dyn_buckets, nbuckets); 486 487 /* Allocate and initialize new hash */ 488 dyn_v = malloc(nbuckets * sizeof(ipfw_dyn_rule), M_IPFW, 489 M_WAITOK | M_ZERO); 490 491 for (i = 0 ; i < nbuckets; i++) 492 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 493 494 /* 495 * Call upper half lock, as get_map() do to ease 496 * read-only access to dynamic rules hash from sysctl 497 */ 498 IPFW_UH_WLOCK(chain); 499 500 /* 501 * Acquire chain write lock to permit hash access 502 * for main traffic path without additional locks 503 */ 504 IPFW_WLOCK(chain); 505 506 /* Save old values */ 507 nbuckets_old = V_curr_dyn_buckets; 508 dyn_v_old = V_ipfw_dyn_v; 509 510 /* Skip relinking if array is not set up */ 511 if (V_ipfw_dyn_v == NULL) 512 V_curr_dyn_buckets = 0; 513 514 /* Re-link all dynamic states */ 515 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 516 while (V_ipfw_dyn_v[i].head != NULL) { 517 /* Remove from current chain */ 518 q = V_ipfw_dyn_v[i].head; 519 V_ipfw_dyn_v[i].head = q->next; 520 521 /* Get new hash value */ 522 k = hash_packet(&q->id, nbuckets); 523 q->bucket = k; 524 /* Add to the new head */ 525 q->next = dyn_v[k].head; 526 dyn_v[k].head = q; 527 } 528 } 529 530 /* Update current pointers/buckets values */ 531 V_curr_dyn_buckets = nbuckets; 532 V_ipfw_dyn_v = dyn_v; 533 534 IPFW_WUNLOCK(chain); 535 536 IPFW_UH_WUNLOCK(chain); 537 538 /* Start periodic callout on initial creation */ 539 if (dyn_v_old == NULL) { 540 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 541 return (0); 542 } 543 544 /* Destroy all mutexes */ 545 for (i = 0 ; i < nbuckets_old ; i++) 546 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 547 548 /* Free old hash */ 549 free(dyn_v_old, M_IPFW); 550 551 return 0; 552} 553 554/** 555 * Install state of type 'type' for a dynamic session. 556 * The hash table contains two type of rules: 557 * - regular rules (O_KEEP_STATE) 558 * - rules for sessions with limited number of sess per user 559 * (O_LIMIT). When they are created, the parent is 560 * increased by 1, and decreased on delete. In this case, 561 * the third parameter is the parent rule and not the chain. 562 * - "parent" rules for the above (O_LIMIT_PARENT). 563 */ 564static ipfw_dyn_rule * 565add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule) 566{ 567 ipfw_dyn_rule *r; 568 569 IPFW_BUCK_ASSERT(i); 570 571 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 572 if (r == NULL) { 573 if (last_log != time_uptime) { 574 last_log = time_uptime; 575 log(LOG_DEBUG, "ipfw: %s: Cannot allocate rule\n", 576 __func__); 577 } 578 return NULL; 579 } 580 581 /* 582 * refcount on parent is already incremented, so 583 * it is safe to use parent unlocked. 584 */ 585 if (dyn_type == O_LIMIT) { 586 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 587 if ( parent->dyn_type != O_LIMIT_PARENT) 588 panic("invalid parent"); 589 r->parent = parent; 590 rule = parent->rule; 591 } 592 593 r->id = *id; 594 r->expire = time_uptime + V_dyn_syn_lifetime; 595 r->rule = rule; 596 r->dyn_type = dyn_type; 597 r->pcnt = r->bcnt = 0; 598 r->count = 0; 599 600 r->bucket = i; 601 r->next = V_ipfw_dyn_v[i].head; 602 V_ipfw_dyn_v[i].head = r; 603 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 604 return r; 605} 606 607/** 608 * lookup dynamic parent rule using pkt and rule as search keys. 609 * If the lookup fails, then install one. 610 */ 611static ipfw_dyn_rule * 612lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule) 613{ 614 ipfw_dyn_rule *q; 615 int i, is_v6; 616 617 is_v6 = IS_IP6_FLOW_ID(pkt); 618 i = hash_packet( pkt, V_curr_dyn_buckets ); 619 *pindex = i; 620 IPFW_BUCK_LOCK(i); 621 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 622 if (q->dyn_type == O_LIMIT_PARENT && 623 rule== q->rule && 624 pkt->proto == q->id.proto && 625 pkt->src_port == q->id.src_port && 626 pkt->dst_port == q->id.dst_port && 627 ( 628 (is_v6 && 629 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 630 &(q->id.src_ip6)) && 631 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 632 &(q->id.dst_ip6))) || 633 (!is_v6 && 634 pkt->src_ip == q->id.src_ip && 635 pkt->dst_ip == q->id.dst_ip) 636 ) 637 ) { 638 q->expire = time_uptime + V_dyn_short_lifetime; 639 DEB(print_dyn_rule(pkt, q->dyn_type, 640 "lookup_dyn_parent found", "");) 641 return q; 642 } 643 644 /* Add virtual limiting rule */ 645 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule); 646} 647 648/** 649 * Install dynamic state for rule type cmd->o.opcode 650 * 651 * Returns 1 (failure) if state is not installed because of errors or because 652 * session limitations are enforced. 653 */ 654int 655ipfw_install_state(struct ip_fw *rule, ipfw_insn_limit *cmd, 656 struct ip_fw_args *args, uint32_t tablearg) 657{ 658 ipfw_dyn_rule *q; 659 int i; 660 661 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");) 662 663 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 664 665 IPFW_BUCK_LOCK(i); 666 667 q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 668 669 if (q != NULL) { /* should never occur */ 670 DEB( 671 if (last_log != time_uptime) { 672 last_log = time_uptime; 673 printf("ipfw: %s: entry already present, done\n", 674 __func__); 675 }) 676 IPFW_BUCK_UNLOCK(i); 677 return (0); 678 } 679 680 /* 681 * State limiting is done via uma(9) zone limiting. 682 * Save pointer to newly-installed rule and reject 683 * packet if add_dyn_rule() returned NULL. 684 * Note q is currently set to NULL. 685 */ 686 687 switch (cmd->o.opcode) { 688 case O_KEEP_STATE: /* bidir rule */ 689 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule); 690 break; 691 692 case O_LIMIT: { /* limit number of sessions */ 693 struct ipfw_flow_id id; 694 ipfw_dyn_rule *parent; 695 uint32_t conn_limit; 696 uint16_t limit_mask = cmd->limit_mask; 697 int pindex; 698 699 conn_limit = IP_FW_ARG_TABLEARG(cmd->conn_limit); 700 701 DEB( 702 if (cmd->conn_limit == IP_FW_TABLEARG) 703 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 704 "(tablearg)\n", __func__, conn_limit); 705 else 706 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 707 __func__, conn_limit); 708 ) 709 710 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 711 id.proto = args->f_id.proto; 712 id.addr_type = args->f_id.addr_type; 713 id.fib = M_GETFIB(args->m); 714 715 if (IS_IP6_FLOW_ID (&(args->f_id))) { 716 if (limit_mask & DYN_SRC_ADDR) 717 id.src_ip6 = args->f_id.src_ip6; 718 if (limit_mask & DYN_DST_ADDR) 719 id.dst_ip6 = args->f_id.dst_ip6; 720 } else { 721 if (limit_mask & DYN_SRC_ADDR) 722 id.src_ip = args->f_id.src_ip; 723 if (limit_mask & DYN_DST_ADDR) 724 id.dst_ip = args->f_id.dst_ip; 725 } 726 if (limit_mask & DYN_SRC_PORT) 727 id.src_port = args->f_id.src_port; 728 if (limit_mask & DYN_DST_PORT) 729 id.dst_port = args->f_id.dst_port; 730 731 /* 732 * We have to release lock for previous bucket to 733 * avoid possible deadlock 734 */ 735 IPFW_BUCK_UNLOCK(i); 736 737 if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) { 738 printf("ipfw: %s: add parent failed\n", __func__); 739 IPFW_BUCK_UNLOCK(pindex); 740 return (1); 741 } 742 743 if (parent->count >= conn_limit) { 744 if (V_fw_verbose && last_log != time_uptime) { 745 last_log = time_uptime; 746 char sbuf[24]; 747 last_log = time_uptime; 748 snprintf(sbuf, sizeof(sbuf), 749 "%d drop session", 750 parent->rule->rulenum); 751 print_dyn_rule_flags(&args->f_id, 752 cmd->o.opcode, 753 LOG_SECURITY | LOG_DEBUG, 754 sbuf, "too many entries"); 755 } 756 IPFW_BUCK_UNLOCK(pindex); 757 return (1); 758 } 759 /* Increment counter on parent */ 760 parent->count++; 761 IPFW_BUCK_UNLOCK(pindex); 762 763 IPFW_BUCK_LOCK(i); 764 q = add_dyn_rule(&args->f_id, i, O_LIMIT, (struct ip_fw *)parent); 765 if (q == NULL) { 766 /* Decrement index and notify caller */ 767 IPFW_BUCK_UNLOCK(i); 768 IPFW_BUCK_LOCK(pindex); 769 parent->count--; 770 IPFW_BUCK_UNLOCK(pindex); 771 return (1); 772 } 773 break; 774 } 775 default: 776 printf("ipfw: %s: unknown dynamic rule type %u\n", 777 __func__, cmd->o.opcode); 778 } 779 780 if (q == NULL) { 781 IPFW_BUCK_UNLOCK(i); 782 return (1); /* Notify caller about failure */ 783 } 784 785 /* XXX just set lifetime */ 786 lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL); 787 788 IPFW_BUCK_UNLOCK(i); 789 return (0); 790} 791 792/* 793 * Generate a TCP packet, containing either a RST or a keepalive. 794 * When flags & TH_RST, we are sending a RST packet, because of a 795 * "reset" action matched the packet. 796 * Otherwise we are sending a keepalive, and flags & TH_ 797 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 798 * so that MAC can label the reply appropriately. 799 */ 800struct mbuf * 801ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 802 u_int32_t ack, int flags) 803{ 804 struct mbuf *m = NULL; /* stupid compiler */ 805 int len, dir; 806 struct ip *h = NULL; /* stupid compiler */ 807#ifdef INET6 808 struct ip6_hdr *h6 = NULL; 809#endif 810 struct tcphdr *th = NULL; 811 812 MGETHDR(m, M_DONTWAIT, MT_DATA); 813 if (m == NULL) 814 return (NULL); 815 816 M_SETFIB(m, id->fib); 817#ifdef MAC 818 if (replyto != NULL) 819 mac_netinet_firewall_reply(replyto, m); 820 else 821 mac_netinet_firewall_send(m); 822#else 823 (void)replyto; /* don't warn about unused arg */ 824#endif 825 826 switch (id->addr_type) { 827 case 4: 828 len = sizeof(struct ip) + sizeof(struct tcphdr); 829 break; 830#ifdef INET6 831 case 6: 832 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 833 break; 834#endif 835 default: 836 /* XXX: log me?!? */ 837 FREE_PKT(m); 838 return (NULL); 839 } 840 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 841 842 m->m_data += max_linkhdr; 843 m->m_flags |= M_SKIP_FIREWALL; 844 m->m_pkthdr.len = m->m_len = len; 845 m->m_pkthdr.rcvif = NULL; 846 bzero(m->m_data, len); 847 848 switch (id->addr_type) { 849 case 4: 850 h = mtod(m, struct ip *); 851 852 /* prepare for checksum */ 853 h->ip_p = IPPROTO_TCP; 854 h->ip_len = htons(sizeof(struct tcphdr)); 855 if (dir) { 856 h->ip_src.s_addr = htonl(id->src_ip); 857 h->ip_dst.s_addr = htonl(id->dst_ip); 858 } else { 859 h->ip_src.s_addr = htonl(id->dst_ip); 860 h->ip_dst.s_addr = htonl(id->src_ip); 861 } 862 863 th = (struct tcphdr *)(h + 1); 864 break; 865#ifdef INET6 866 case 6: 867 h6 = mtod(m, struct ip6_hdr *); 868 869 /* prepare for checksum */ 870 h6->ip6_nxt = IPPROTO_TCP; 871 h6->ip6_plen = htons(sizeof(struct tcphdr)); 872 if (dir) { 873 h6->ip6_src = id->src_ip6; 874 h6->ip6_dst = id->dst_ip6; 875 } else { 876 h6->ip6_src = id->dst_ip6; 877 h6->ip6_dst = id->src_ip6; 878 } 879 880 th = (struct tcphdr *)(h6 + 1); 881 break; 882#endif 883 } 884 885 if (dir) { 886 th->th_sport = htons(id->src_port); 887 th->th_dport = htons(id->dst_port); 888 } else { 889 th->th_sport = htons(id->dst_port); 890 th->th_dport = htons(id->src_port); 891 } 892 th->th_off = sizeof(struct tcphdr) >> 2; 893 894 if (flags & TH_RST) { 895 if (flags & TH_ACK) { 896 th->th_seq = htonl(ack); 897 th->th_flags = TH_RST; 898 } else { 899 if (flags & TH_SYN) 900 seq++; 901 th->th_ack = htonl(seq); 902 th->th_flags = TH_RST | TH_ACK; 903 } 904 } else { 905 /* 906 * Keepalive - use caller provided sequence numbers 907 */ 908 th->th_seq = htonl(seq); 909 th->th_ack = htonl(ack); 910 th->th_flags = TH_ACK; 911 } 912 913 switch (id->addr_type) { 914 case 4: 915 th->th_sum = in_cksum(m, len); 916 917 /* finish the ip header */ 918 h->ip_v = 4; 919 h->ip_hl = sizeof(*h) >> 2; 920 h->ip_tos = IPTOS_LOWDELAY; 921 h->ip_off = 0; 922 /* ip_len must be in host format for ip_output */ 923 h->ip_len = len; 924 h->ip_ttl = V_ip_defttl; 925 h->ip_sum = 0; 926 break; 927#ifdef INET6 928 case 6: 929 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 930 sizeof(struct tcphdr)); 931 932 /* finish the ip6 header */ 933 h6->ip6_vfc |= IPV6_VERSION; 934 h6->ip6_hlim = IPV6_DEFHLIM; 935 break; 936#endif 937 } 938 939 return (m); 940} 941 942/* 943 * Queue keepalive packets for given dynamic rule 944 */ 945static struct mbuf ** 946ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 947{ 948 struct mbuf *m_rev, *m_fwd; 949 950 m_rev = (q->state & ACK_REV) ? NULL : 951 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 952 m_fwd = (q->state & ACK_FWD) ? NULL : 953 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 954 955 if (m_rev != NULL) { 956 *mtailp = m_rev; 957 mtailp = &(*mtailp)->m_nextpkt; 958 } 959 if (m_fwd != NULL) { 960 *mtailp = m_fwd; 961 mtailp = &(*mtailp)->m_nextpkt; 962 } 963 964 return (mtailp); 965} 966 967/* 968 * This procedure is used to perform various maintance 969 * on dynamic hash list. Currently it is called every second. 970 */ 971static void 972ipfw_dyn_tick(void * vnetx) 973{ 974 struct ip_fw_chain *chain; 975 int check_ka = 0; 976#ifdef VIMAGE 977 struct vnet *vp = vnetx; 978#endif 979 980 CURVNET_SET(vp); 981 982 chain = &V_layer3_chain; 983 984 /* Run keepalive checks every keepalive_period iff ka is enabled */ 985 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 986 (V_dyn_keepalive != 0)) { 987 V_dyn_keepalive_last = time_uptime; 988 check_ka = 1; 989 } 990 991 check_dyn_rules(chain, NULL, RESVD_SET, check_ka, 1); 992 993 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 994 995 CURVNET_RESTORE(); 996} 997 998 999/* 1000 * Walk thru all dynamic states doing generic maintance: 1001 * 1) free expired states 1002 * 2) free all states based on deleted rule / set 1003 * 3) send keepalives for states if needed 1004 * 1005 * @chain - pointer to current ipfw rules chain 1006 * @rule - delete all states originated by given rule if != NULL 1007 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1008 * @check_ka - perform checking/sending keepalives 1009 * @timer - indicate call from timer routine. 1010 * 1011 * Timer routine must call this function unlocked to permit 1012 * sending keepalives/resizing table. 1013 * 1014 * Others has to call function with IPFW_UH_WLOCK held. 1015 * Additionally, function assume that dynamic rule/set is 1016 * ALREADY deleted so no new states can be generated by 1017 * 'deleted' rules. 1018 * 1019 * Write lock is needed to ensure that unused parent rules 1020 * are not freed by other instance (see stage 2, 3) 1021 */ 1022static void 1023check_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, 1024 int set, int check_ka, int timer) 1025{ 1026 struct mbuf *m0, *m, *mnext, **mtailp; 1027 struct ip *h; 1028 int i, dyn_count, new_buckets = 0, max_buckets; 1029 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1030 ipfw_dyn_rule *q, *q_prev, *q_next; 1031 ipfw_dyn_rule *exp_head, **exptailp; 1032 ipfw_dyn_rule *exp_lhead, **expltailp; 1033 1034 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1035 __func__)); 1036 1037 /* Avoid possible LOR */ 1038 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1039 __func__)); 1040 1041 /* 1042 * Do not perform any checks if we currently have no dynamic states 1043 */ 1044 if (DYN_COUNT == 0) 1045 return; 1046 1047 /* Expired states */ 1048 exp_head = NULL; 1049 exptailp = &exp_head; 1050 1051 /* Expired limit states */ 1052 exp_lhead = NULL; 1053 expltailp = &exp_lhead; 1054 1055 /* 1056 * We make a chain of packets to go out here -- not deferring 1057 * until after we drop the IPFW dynamic rule lock would result 1058 * in a lock order reversal with the normal packet input -> ipfw 1059 * call stack. 1060 */ 1061 m0 = NULL; 1062 mtailp = &m0; 1063 1064 /* Protect from hash resizing */ 1065 if (timer != 0) 1066 IPFW_UH_WLOCK(chain); 1067 else 1068 IPFW_UH_WLOCK_ASSERT(chain); 1069 1070#define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1071 1072 /* Stage 1: perform requested deletion */ 1073 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1074 IPFW_BUCK_LOCK(i); 1075 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1076 /* account every rule */ 1077 total++; 1078 1079 /* Skip parent rules at all */ 1080 if (q->dyn_type == O_LIMIT_PARENT) { 1081 parents++; 1082 NEXT_RULE(); 1083 } 1084 1085 /* 1086 * Remove rules which are: 1087 * 1) expired 1088 * 2) created by given rule 1089 * 3) created by any rule in given set 1090 */ 1091 if ((TIME_LEQ(q->expire, time_uptime)) || 1092 ((rule != NULL) && (q->rule == rule)) || 1093 ((set != RESVD_SET) && (q->rule->set == set))) { 1094 /* Unlink q from current list */ 1095 q_next = q->next; 1096 if (q == V_ipfw_dyn_v[i].head) 1097 V_ipfw_dyn_v[i].head = q_next; 1098 else 1099 q_prev->next = q_next; 1100 1101 q->next = NULL; 1102 1103 /* queue q to expire list */ 1104 if (q->dyn_type != O_LIMIT) { 1105 *exptailp = q; 1106 exptailp = &(*exptailp)->next; 1107 DEB(print_dyn_rule(&q->id, q->dyn_type, 1108 "unlink entry", "left"); 1109 ) 1110 } else { 1111 /* Separate list for limit rules */ 1112 *expltailp = q; 1113 expltailp = &(*expltailp)->next; 1114 expired_limits++; 1115 DEB(print_dyn_rule(&q->id, q->dyn_type, 1116 "unlink limit entry", "left"); 1117 ) 1118 } 1119 1120 q = q_next; 1121 expired++; 1122 continue; 1123 } 1124 1125 /* 1126 * Check if we need to send keepalive: 1127 * we need to ensure if is time to do KA, 1128 * this is established TCP session, and 1129 * expire time is within keepalive interval 1130 */ 1131 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1132 ((q->state & BOTH_SYN) == BOTH_SYN) && 1133 (TIME_LEQ(q->expire, time_uptime + 1134 V_dyn_keepalive_interval))) 1135 mtailp = ipfw_dyn_send_ka(mtailp, q); 1136 1137 NEXT_RULE(); 1138 } 1139 IPFW_BUCK_UNLOCK(i); 1140 } 1141 1142 /* Stage 2: decrement counters from O_LIMIT parents */ 1143 if (expired_limits != 0) { 1144 /* 1145 * XXX: Note that deleting set with more than one 1146 * heavily-used LIMIT rules can result in overwhelming 1147 * locking due to lack of per-hash value sorting 1148 * 1149 * We should probably think about: 1150 * 1) pre-allocating hash of size, say, 1151 * MAX(16, V_curr_dyn_buckets / 1024) 1152 * 2) checking if expired_limits is large enough 1153 * 3) If yes, init hash (or its part), re-link 1154 * current list and start decrementing procedure in 1155 * each bucket separately 1156 */ 1157 1158 /* 1159 * Small optimization: do not unlock bucket until 1160 * we see the next item resides in different bucket 1161 */ 1162 if (exp_lhead != NULL) { 1163 i = exp_lhead->parent->bucket; 1164 IPFW_BUCK_LOCK(i); 1165 } 1166 for (q = exp_lhead; q != NULL; q = q->next) { 1167 if (i != q->parent->bucket) { 1168 IPFW_BUCK_UNLOCK(i); 1169 i = q->parent->bucket; 1170 IPFW_BUCK_LOCK(i); 1171 } 1172 1173 /* Decrease parent refcount */ 1174 q->parent->count--; 1175 } 1176 if (exp_lhead != NULL) 1177 IPFW_BUCK_UNLOCK(i); 1178 } 1179 1180 /* 1181 * We protectet ourselves from unused parent deletion 1182 * (from the timer function) by holding UH write lock. 1183 */ 1184 1185 /* Stage 3: remove unused parent rules */ 1186 if ((parents != 0) && (expired != 0)) { 1187 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1188 IPFW_BUCK_LOCK(i); 1189 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1190 if (q->dyn_type != O_LIMIT_PARENT) 1191 NEXT_RULE(); 1192 1193 if (q->count != 0) 1194 NEXT_RULE(); 1195 1196 /* Parent rule without consumers */ 1197 1198 /* Unlink q from current list */ 1199 q_next = q->next; 1200 if (q == V_ipfw_dyn_v[i].head) 1201 V_ipfw_dyn_v[i].head = q_next; 1202 else 1203 q_prev->next = q_next; 1204 1205 q->next = NULL; 1206 1207 /* Add to expired list */ 1208 *exptailp = q; 1209 exptailp = &(*exptailp)->next; 1210 1211 DEB(print_dyn_rule(&q->id, q->dyn_type, 1212 "unlink parent entry", "left"); 1213 ) 1214 1215 expired++; 1216 1217 q = q_next; 1218 } 1219 IPFW_BUCK_UNLOCK(i); 1220 } 1221 } 1222 1223#undef NEXT_RULE 1224 1225 if (timer != 0) { 1226 /* 1227 * Check if we need to resize hash: 1228 * if current number of states exceeds number of buckes in hash, 1229 * grow hash size to the minimum power of 2 which is bigger than 1230 * current states count. Limit hash size by 64k. 1231 */ 1232 max_buckets = (V_dyn_buckets_max > 65536) ? 1233 65536 : V_dyn_buckets_max; 1234 1235 dyn_count = DYN_COUNT; 1236 1237 if ((dyn_count > V_curr_dyn_buckets * 2) && 1238 (dyn_count < max_buckets)) { 1239 new_buckets = V_curr_dyn_buckets; 1240 while (new_buckets < dyn_count) { 1241 new_buckets *= 2; 1242 1243 if (new_buckets >= max_buckets) 1244 break; 1245 } 1246 } 1247 1248 IPFW_UH_WUNLOCK(chain); 1249 } 1250 1251 /* Finally delete old states ad limits if any */ 1252 for (q = exp_head; q != NULL; q = q_next) { 1253 q_next = q->next; 1254 uma_zfree(V_ipfw_dyn_rule_zone, q); 1255 } 1256 1257 for (q = exp_lhead; q != NULL; q = q_next) { 1258 q_next = q->next; 1259 uma_zfree(V_ipfw_dyn_rule_zone, q); 1260 } 1261 1262 /* 1263 * The rest code MUST be called from timer routine only 1264 * without holding any locks 1265 */ 1266 if (timer == 0) 1267 return; 1268 1269 /* Send keepalive packets if any */ 1270 for (m = m0; m != NULL; m = mnext) { 1271 mnext = m->m_nextpkt; 1272 m->m_nextpkt = NULL; 1273 h = mtod(m, struct ip *); 1274 if (h->ip_v == 4) 1275 ip_output(m, NULL, NULL, 0, NULL, NULL); 1276#ifdef INET6 1277 else 1278 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1279#endif 1280 } 1281 1282 /* Run table resize without holding any locks */ 1283 if (new_buckets != 0) 1284 resize_dynamic_table(chain, new_buckets); 1285} 1286 1287/* 1288 * Deletes all dynamic rules originated by given rule or all rules in 1289 * given set. Specify RESVD_SET to indicate set should not be used. 1290 * @chain - pointer to current ipfw rules chain 1291 * @rule - delete all states originated by given rule if != NULL 1292 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1293 * 1294 * Function has to be called with IPFW_UH_WLOCK held. 1295 * Additionally, function assume that dynamic rule/set is 1296 * ALREADY deleted so no new states can be generated by 1297 * 'deleted' rules. 1298 */ 1299void 1300ipfw_expire_dyn_rules(struct ip_fw_chain *chain, struct ip_fw *rule, int set) 1301{ 1302 1303 check_dyn_rules(chain, rule, set, 0, 0); 1304} 1305 1306void 1307ipfw_dyn_init(struct ip_fw_chain *chain) 1308{ 1309 1310 V_ipfw_dyn_v = NULL; 1311 V_dyn_buckets_max = 256; /* must be power of 2 */ 1312 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1313 1314 V_dyn_ack_lifetime = 300; 1315 V_dyn_syn_lifetime = 20; 1316 V_dyn_fin_lifetime = 1; 1317 V_dyn_rst_lifetime = 1; 1318 V_dyn_udp_lifetime = 10; 1319 V_dyn_short_lifetime = 5; 1320 1321 V_dyn_keepalive_interval = 20; 1322 V_dyn_keepalive_period = 5; 1323 V_dyn_keepalive = 1; /* do send keepalives */ 1324 V_dyn_keepalive_last = time_uptime; 1325 1326 V_dyn_max = 4096; /* max # of dynamic rules */ 1327 1328 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1329 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1330 UMA_ALIGN_PTR, 0); 1331 1332 /* Enforce limit on dynamic rules */ 1333 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1334 1335 callout_init(&V_ipfw_timeout, CALLOUT_MPSAFE); 1336 1337 /* 1338 * This can potentially be done on first dynamic rule 1339 * being added to chain. 1340 */ 1341 resize_dynamic_table(chain, V_curr_dyn_buckets); 1342} 1343 1344void 1345ipfw_dyn_uninit(int pass) 1346{ 1347 int i; 1348 1349 if (pass == 0) { 1350 callout_drain(&V_ipfw_timeout); 1351 return; 1352 } 1353 1354 if (V_ipfw_dyn_v != NULL) { 1355 /* 1356 * Skip deleting all dynamic states - 1357 * uma_zdestroy() does this more efficiently; 1358 */ 1359 1360 /* Destroy all mutexes */ 1361 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1362 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1363 free(V_ipfw_dyn_v, M_IPFW); 1364 V_ipfw_dyn_v = NULL; 1365 } 1366 1367 uma_zdestroy(V_ipfw_dyn_rule_zone); 1368} 1369 1370#ifdef SYSCTL_NODE 1371/* 1372 * Get/set maximum number of dynamic states in given VNET instance. 1373 */ 1374static int 1375sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1376{ 1377 int error; 1378 unsigned int nstates; 1379 1380 nstates = V_dyn_max; 1381 1382 error = sysctl_handle_int(oidp, &nstates, 0, req); 1383 /* Read operation or some error */ 1384 if ((error != 0) || (req->newptr == NULL)) 1385 return (error); 1386 1387 V_dyn_max = nstates; 1388 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1389 1390 return (0); 1391} 1392 1393/* 1394 * Get current number of dynamic states in given VNET instance. 1395 */ 1396static int 1397sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1398{ 1399 int error; 1400 unsigned int nstates; 1401 1402 nstates = DYN_COUNT; 1403 1404 error = sysctl_handle_int(oidp, &nstates, 0, req); 1405 1406 return (error); 1407} 1408#endif 1409 1410/* 1411 * Returns number of dynamic rules. 1412 */ 1413int 1414ipfw_dyn_len(void) 1415{ 1416 1417 return (V_ipfw_dyn_v == NULL) ? 0 : 1418 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1419} 1420 1421/* 1422 * Fill given buffer with dynamic states. 1423 * IPFW_UH_RLOCK has to be held while calling. 1424 */ 1425void 1426ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1427{ 1428 ipfw_dyn_rule *p, *last = NULL; 1429 char *bp; 1430 int i; 1431 1432 if (V_ipfw_dyn_v == NULL) 1433 return; 1434 bp = *pbp; 1435 1436 IPFW_UH_RLOCK_ASSERT(chain); 1437 1438 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1439 IPFW_BUCK_LOCK(i); 1440 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1441 if (bp + sizeof *p <= ep) { 1442 ipfw_dyn_rule *dst = 1443 (ipfw_dyn_rule *)bp; 1444 bcopy(p, dst, sizeof *p); 1445 bcopy(&(p->rule->rulenum), &(dst->rule), 1446 sizeof(p->rule->rulenum)); 1447 /* 1448 * store set number into high word of 1449 * dst->rule pointer. 1450 */ 1451 bcopy(&(p->rule->set), 1452 (char *)&dst->rule + 1453 sizeof(p->rule->rulenum), 1454 sizeof(p->rule->set)); 1455 /* 1456 * store a non-null value in "next". 1457 * The userland code will interpret a 1458 * NULL here as a marker 1459 * for the last dynamic rule. 1460 */ 1461 bcopy(&dst, &dst->next, sizeof(dst)); 1462 last = dst; 1463 dst->expire = 1464 TIME_LEQ(dst->expire, time_uptime) ? 1465 0 : dst->expire - time_uptime ; 1466 bp += sizeof(ipfw_dyn_rule); 1467 } 1468 } 1469 IPFW_BUCK_UNLOCK(i); 1470 } 1471 1472 if (last != NULL) /* mark last dynamic rule */ 1473 bzero(&last->next, sizeof(last)); 1474 *pbp = bp; 1475} 1476/* end of file */ 1477