ip_fw_dynamic.c revision 326388
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/11/sys/netpfil/ipfw/ip_fw_dynamic.c 326388 2017-11-30 07:42:56Z ae $"); 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/pfil.h> 58#include <net/vnet.h> 59 60#include <netinet/in.h> 61#include <netinet/ip.h> 62#include <netinet/ip_var.h> /* ip_defttl */ 63#include <netinet/ip_fw.h> 64#include <netinet/tcp_var.h> 65#include <netinet/udp.h> 66 67#include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */ 68#ifdef INET6 69#include <netinet6/in6_var.h> 70#include <netinet6/ip6_var.h> 71#endif 72 73#include <netpfil/ipfw/ip_fw_private.h> 74 75#include <machine/in_cksum.h> /* XXX for in_cksum */ 76 77#ifdef MAC 78#include <security/mac/mac_framework.h> 79#endif 80 81/* 82 * Description of dynamic rules. 83 * 84 * Dynamic rules are stored in lists accessed through a hash table 85 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can 86 * be modified through the sysctl variable dyn_buckets which is 87 * updated when the table becomes empty. 88 * 89 * XXX currently there is only one list, ipfw_dyn. 90 * 91 * When a packet is received, its address fields are first masked 92 * with the mask defined for the rule, then hashed, then matched 93 * against the entries in the corresponding list. 94 * Dynamic rules can be used for different purposes: 95 * + stateful rules; 96 * + enforcing limits on the number of sessions; 97 * + in-kernel NAT (not implemented yet) 98 * 99 * The lifetime of dynamic rules is regulated by dyn_*_lifetime, 100 * measured in seconds and depending on the flags. 101 * 102 * The total number of dynamic rules is equal to UMA zone items count. 103 * The max number of dynamic rules is dyn_max. When we reach 104 * the maximum number of rules we do not create anymore. This is 105 * done to avoid consuming too much memory, but also too much 106 * time when searching on each packet (ideally, we should try instead 107 * to put a limit on the length of the list on each bucket...). 108 * 109 * Each dynamic rule holds a pointer to the parent ipfw rule so 110 * we know what action to perform. Dynamic rules are removed when 111 * the parent rule is deleted. This can be changed by dyn_keep_states 112 * sysctl. 113 * 114 * There are some limitations with dynamic rules -- we do not 115 * obey the 'randomized match', and we do not do multiple 116 * passes through the firewall. XXX check the latter!!! 117 */ 118 119struct ipfw_dyn_bucket { 120 struct mtx mtx; /* Bucket protecting lock */ 121 ipfw_dyn_rule *head; /* Pointer to first rule */ 122}; 123 124/* 125 * Static variables followed by global ones 126 */ 127static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v); 128static VNET_DEFINE(u_int32_t, dyn_buckets_max); 129static VNET_DEFINE(u_int32_t, curr_dyn_buckets); 130static VNET_DEFINE(struct callout, ipfw_timeout); 131#define V_ipfw_dyn_v VNET(ipfw_dyn_v) 132#define V_dyn_buckets_max VNET(dyn_buckets_max) 133#define V_curr_dyn_buckets VNET(curr_dyn_buckets) 134#define V_ipfw_timeout VNET(ipfw_timeout) 135 136static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone); 137#define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone) 138 139#define IPFW_BUCK_LOCK_INIT(b) \ 140 mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF) 141#define IPFW_BUCK_LOCK_DESTROY(b) \ 142 mtx_destroy(&(b)->mtx) 143#define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx) 144#define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx) 145#define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED) 146 147 148static VNET_DEFINE(int, dyn_keep_states); 149#define V_dyn_keep_states VNET(dyn_keep_states) 150 151/* 152 * Timeouts for various events in handing dynamic rules. 153 */ 154static VNET_DEFINE(u_int32_t, dyn_ack_lifetime); 155static VNET_DEFINE(u_int32_t, dyn_syn_lifetime); 156static VNET_DEFINE(u_int32_t, dyn_fin_lifetime); 157static VNET_DEFINE(u_int32_t, dyn_rst_lifetime); 158static VNET_DEFINE(u_int32_t, dyn_udp_lifetime); 159static VNET_DEFINE(u_int32_t, dyn_short_lifetime); 160 161#define V_dyn_ack_lifetime VNET(dyn_ack_lifetime) 162#define V_dyn_syn_lifetime VNET(dyn_syn_lifetime) 163#define V_dyn_fin_lifetime VNET(dyn_fin_lifetime) 164#define V_dyn_rst_lifetime VNET(dyn_rst_lifetime) 165#define V_dyn_udp_lifetime VNET(dyn_udp_lifetime) 166#define V_dyn_short_lifetime VNET(dyn_short_lifetime) 167 168/* 169 * Keepalives are sent if dyn_keepalive is set. They are sent every 170 * dyn_keepalive_period seconds, in the last dyn_keepalive_interval 171 * seconds of lifetime of a rule. 172 * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower 173 * than dyn_keepalive_period. 174 */ 175 176static VNET_DEFINE(u_int32_t, dyn_keepalive_interval); 177static VNET_DEFINE(u_int32_t, dyn_keepalive_period); 178static VNET_DEFINE(u_int32_t, dyn_keepalive); 179static VNET_DEFINE(time_t, dyn_keepalive_last); 180 181#define V_dyn_keepalive_interval VNET(dyn_keepalive_interval) 182#define V_dyn_keepalive_period VNET(dyn_keepalive_period) 183#define V_dyn_keepalive VNET(dyn_keepalive) 184#define V_dyn_keepalive_last VNET(dyn_keepalive_last) 185 186static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */ 187 188#define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone) 189#define V_dyn_max VNET(dyn_max) 190 191/* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */ 192static int ipfw_dyn_count; /* number of objects */ 193 194#ifdef USERSPACE /* emulation of UMA object counters for userspace */ 195#define uma_zone_get_cur(x) ipfw_dyn_count 196#endif /* USERSPACE */ 197 198static int last_log; /* Log ratelimiting */ 199 200static void ipfw_dyn_tick(void *vnetx); 201static void check_dyn_rules(struct ip_fw_chain *, ipfw_range_tlv *, int, int); 202#ifdef SYSCTL_NODE 203 204static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS); 205static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS); 206 207SYSBEGIN(f2) 208 209SYSCTL_DECL(_net_inet_ip_fw); 210SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, 211 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0, 212 "Max number of dyn. buckets"); 213SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, 214 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0, 215 "Current Number of dyn. buckets"); 216SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count, 217 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU", 218 "Number of dyn. rules"); 219SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max, 220 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU", 221 "Max number of dyn. rules"); 222SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, 223 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0, 224 "Lifetime of dyn. rules for acks"); 225SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, 226 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0, 227 "Lifetime of dyn. rules for syn"); 228SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, 229 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0, 230 "Lifetime of dyn. rules for fin"); 231SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, 232 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0, 233 "Lifetime of dyn. rules for rst"); 234SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, 235 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0, 236 "Lifetime of dyn. rules for UDP"); 237SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, 238 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0, 239 "Lifetime of dyn. rules for other situations"); 240SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, 241 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0, 242 "Enable keepalives for dyn. rules"); 243SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states, 244 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0, 245 "Do not flush dynamic states on rule deletion"); 246 247SYSEND 248 249#endif /* SYSCTL_NODE */ 250 251 252#ifdef INET6 253static __inline int 254hash_packet6(const struct ipfw_flow_id *id) 255{ 256 u_int32_t i; 257 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^ 258 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^ 259 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^ 260 (id->src_ip6.__u6_addr.__u6_addr32[3]); 261 return ntohl(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 */ 270static __inline int 271hash_packet(const 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); 281 i ^= (id->dst_port) ^ (id->src_port); 282 return (i & (buckets - 1)); 283} 284 285#if 0 286#define DYN_DEBUG(fmt, ...) do { \ 287 printf("%s: " fmt "\n", __func__, __VA_ARGS__); \ 288} while (0) 289#else 290#define DYN_DEBUG(fmt, ...) 291#endif 292 293static char *default_state_name = "default"; 294struct dyn_state_obj { 295 struct named_object no; 296 char name[64]; 297}; 298 299#define DYN_STATE_OBJ(ch, cmd) \ 300 ((struct dyn_state_obj *)SRV_OBJECT(ch, (cmd)->arg1)) 301/* 302 * Classifier callback. 303 * Return 0 if opcode contains object that should be referenced 304 * or rewritten. 305 */ 306static int 307dyn_classify(ipfw_insn *cmd, uint16_t *puidx, uint8_t *ptype) 308{ 309 310 DYN_DEBUG("opcode %d, arg1 %d", cmd->opcode, cmd->arg1); 311 /* Don't rewrite "check-state any" */ 312 if (cmd->arg1 == 0 && 313 cmd->opcode == O_CHECK_STATE) 314 return (1); 315 316 *puidx = cmd->arg1; 317 *ptype = 0; 318 return (0); 319} 320 321static void 322dyn_update(ipfw_insn *cmd, uint16_t idx) 323{ 324 325 cmd->arg1 = idx; 326 DYN_DEBUG("opcode %d, arg1 %d", cmd->opcode, cmd->arg1); 327} 328 329static int 330dyn_findbyname(struct ip_fw_chain *ch, struct tid_info *ti, 331 struct named_object **pno) 332{ 333 ipfw_obj_ntlv *ntlv; 334 const char *name; 335 336 DYN_DEBUG("uidx %d", ti->uidx); 337 if (ti->uidx != 0) { 338 if (ti->tlvs == NULL) 339 return (EINVAL); 340 /* Search ntlv in the buffer provided by user */ 341 ntlv = ipfw_find_name_tlv_type(ti->tlvs, ti->tlen, ti->uidx, 342 IPFW_TLV_STATE_NAME); 343 if (ntlv == NULL) 344 return (EINVAL); 345 name = ntlv->name; 346 } else 347 name = default_state_name; 348 /* 349 * Search named object with corresponding name. 350 * Since states objects are global - ignore the set value 351 * and use zero instead. 352 */ 353 *pno = ipfw_objhash_lookup_name_type(CHAIN_TO_SRV(ch), 0, 354 IPFW_TLV_STATE_NAME, name); 355 /* 356 * We always return success here. 357 * The caller will check *pno and mark object as unresolved, 358 * then it will automatically create "default" object. 359 */ 360 return (0); 361} 362 363static struct named_object * 364dyn_findbykidx(struct ip_fw_chain *ch, uint16_t idx) 365{ 366 367 DYN_DEBUG("kidx %d", idx); 368 return (ipfw_objhash_lookup_kidx(CHAIN_TO_SRV(ch), idx)); 369} 370 371static int 372dyn_create(struct ip_fw_chain *ch, struct tid_info *ti, 373 uint16_t *pkidx) 374{ 375 struct namedobj_instance *ni; 376 struct dyn_state_obj *obj; 377 struct named_object *no; 378 ipfw_obj_ntlv *ntlv; 379 char *name; 380 381 DYN_DEBUG("uidx %d", ti->uidx); 382 if (ti->uidx != 0) { 383 if (ti->tlvs == NULL) 384 return (EINVAL); 385 ntlv = ipfw_find_name_tlv_type(ti->tlvs, ti->tlen, ti->uidx, 386 IPFW_TLV_STATE_NAME); 387 if (ntlv == NULL) 388 return (EINVAL); 389 name = ntlv->name; 390 } else 391 name = default_state_name; 392 393 ni = CHAIN_TO_SRV(ch); 394 obj = malloc(sizeof(*obj), M_IPFW, M_WAITOK | M_ZERO); 395 obj->no.name = obj->name; 396 obj->no.etlv = IPFW_TLV_STATE_NAME; 397 strlcpy(obj->name, name, sizeof(obj->name)); 398 399 IPFW_UH_WLOCK(ch); 400 no = ipfw_objhash_lookup_name_type(ni, 0, 401 IPFW_TLV_STATE_NAME, name); 402 if (no != NULL) { 403 /* 404 * Object is already created. 405 * Just return its kidx and bump refcount. 406 */ 407 *pkidx = no->kidx; 408 no->refcnt++; 409 IPFW_UH_WUNLOCK(ch); 410 free(obj, M_IPFW); 411 DYN_DEBUG("\tfound kidx %d", *pkidx); 412 return (0); 413 } 414 if (ipfw_objhash_alloc_idx(ni, &obj->no.kidx) != 0) { 415 DYN_DEBUG("\talloc_idx failed for %s", name); 416 IPFW_UH_WUNLOCK(ch); 417 free(obj, M_IPFW); 418 return (ENOSPC); 419 } 420 ipfw_objhash_add(ni, &obj->no); 421 SRV_OBJECT(ch, obj->no.kidx) = obj; 422 obj->no.refcnt++; 423 *pkidx = obj->no.kidx; 424 IPFW_UH_WUNLOCK(ch); 425 DYN_DEBUG("\tcreated kidx %d", *pkidx); 426 return (0); 427} 428 429static void 430dyn_destroy(struct ip_fw_chain *ch, struct named_object *no) 431{ 432 struct dyn_state_obj *obj; 433 434 IPFW_UH_WLOCK_ASSERT(ch); 435 436 KASSERT(no->refcnt == 1, 437 ("Destroying object '%s' (type %u, idx %u) with refcnt %u", 438 no->name, no->etlv, no->kidx, no->refcnt)); 439 440 DYN_DEBUG("kidx %d", no->kidx); 441 obj = SRV_OBJECT(ch, no->kidx); 442 SRV_OBJECT(ch, no->kidx) = NULL; 443 ipfw_objhash_del(CHAIN_TO_SRV(ch), no); 444 ipfw_objhash_free_idx(CHAIN_TO_SRV(ch), no->kidx); 445 446 free(obj, M_IPFW); 447} 448 449static struct opcode_obj_rewrite dyn_opcodes[] = { 450 { 451 O_KEEP_STATE, IPFW_TLV_STATE_NAME, 452 dyn_classify, dyn_update, 453 dyn_findbyname, dyn_findbykidx, 454 dyn_create, dyn_destroy 455 }, 456 { 457 O_CHECK_STATE, IPFW_TLV_STATE_NAME, 458 dyn_classify, dyn_update, 459 dyn_findbyname, dyn_findbykidx, 460 dyn_create, dyn_destroy 461 }, 462 { 463 O_PROBE_STATE, IPFW_TLV_STATE_NAME, 464 dyn_classify, dyn_update, 465 dyn_findbyname, dyn_findbykidx, 466 dyn_create, dyn_destroy 467 }, 468 { 469 O_LIMIT, IPFW_TLV_STATE_NAME, 470 dyn_classify, dyn_update, 471 dyn_findbyname, dyn_findbykidx, 472 dyn_create, dyn_destroy 473 }, 474}; 475/** 476 * Print customizable flow id description via log(9) facility. 477 */ 478static void 479print_dyn_rule_flags(const struct ipfw_flow_id *id, int dyn_type, 480 int log_flags, char *prefix, char *postfix) 481{ 482 struct in_addr da; 483#ifdef INET6 484 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 485#else 486 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 487#endif 488 489#ifdef INET6 490 if (IS_IP6_FLOW_ID(id)) { 491 ip6_sprintf(src, &id->src_ip6); 492 ip6_sprintf(dst, &id->dst_ip6); 493 } else 494#endif 495 { 496 da.s_addr = htonl(id->src_ip); 497 inet_ntop(AF_INET, &da, src, sizeof(src)); 498 da.s_addr = htonl(id->dst_ip); 499 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 500 } 501 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 502 prefix, dyn_type, src, id->src_port, dst, 503 id->dst_port, DYN_COUNT, postfix); 504} 505 506#define print_dyn_rule(id, dtype, prefix, postfix) \ 507 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 508 509#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 510#define TIME_LE(a,b) ((int)((a)-(b)) < 0) 511 512static void 513dyn_update_proto_state(ipfw_dyn_rule *q, const struct ipfw_flow_id *id, 514 const void *ulp, int dir) 515{ 516 const struct tcphdr *tcp; 517 uint32_t ack; 518 u_char flags; 519 520 if (id->proto == IPPROTO_TCP) { 521 tcp = (const struct tcphdr *)ulp; 522 flags = id->_flags & (TH_FIN | TH_SYN | TH_RST); 523#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 524#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 525#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 526#define ACK_FWD 0x10000 /* fwd ack seen */ 527#define ACK_REV 0x20000 /* rev ack seen */ 528 529 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 530 switch (q->state & TCP_FLAGS) { 531 case TH_SYN: /* opening */ 532 q->expire = time_uptime + V_dyn_syn_lifetime; 533 break; 534 535 case BOTH_SYN: /* move to established */ 536 case BOTH_SYN | TH_FIN: /* one side tries to close */ 537 case BOTH_SYN | (TH_FIN << 8): 538#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 539 if (tcp == NULL) 540 break; 541 542 ack = ntohl(tcp->th_ack); 543 if (dir == MATCH_FORWARD) { 544 if (q->ack_fwd == 0 || 545 _SEQ_GE(ack, q->ack_fwd)) { 546 q->ack_fwd = ack; 547 q->state |= ACK_FWD; 548 } 549 } else { 550 if (q->ack_rev == 0 || 551 _SEQ_GE(ack, q->ack_rev)) { 552 q->ack_rev = ack; 553 q->state |= ACK_REV; 554 } 555 } 556 if ((q->state & (ACK_FWD | ACK_REV)) == 557 (ACK_FWD | ACK_REV)) { 558 q->expire = time_uptime + V_dyn_ack_lifetime; 559 q->state &= ~(ACK_FWD | ACK_REV); 560 } 561 break; 562 563 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 564 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 565 V_dyn_fin_lifetime = 566 V_dyn_keepalive_period - 1; 567 q->expire = time_uptime + V_dyn_fin_lifetime; 568 break; 569 570 default: 571#if 0 572 /* 573 * reset or some invalid combination, but can also 574 * occur if we use keep-state the wrong way. 575 */ 576 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 577 printf("invalid state: 0x%x\n", q->state); 578#endif 579 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 580 V_dyn_rst_lifetime = 581 V_dyn_keepalive_period - 1; 582 q->expire = time_uptime + V_dyn_rst_lifetime; 583 break; 584 } 585 } else if (id->proto == IPPROTO_UDP) { 586 q->expire = time_uptime + V_dyn_udp_lifetime; 587 } else { 588 /* other protocols */ 589 q->expire = time_uptime + V_dyn_short_lifetime; 590 } 591} 592 593/* 594 * Lookup a dynamic rule, locked version. 595 */ 596static ipfw_dyn_rule * 597lookup_dyn_rule_locked(const struct ipfw_flow_id *pkt, const void *ulp, 598 int i, int *match_direction, uint16_t kidx) 599{ 600 /* 601 * Stateful ipfw extensions. 602 * Lookup into dynamic session queue. 603 */ 604 ipfw_dyn_rule *prev, *q = NULL; 605 int dir; 606 607 IPFW_BUCK_ASSERT(i); 608 609 dir = MATCH_NONE; 610 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 611 if (q->dyn_type == O_LIMIT_PARENT) 612 continue; 613 614 if (pkt->addr_type != q->id.addr_type) 615 continue; 616 617 if (pkt->proto != q->id.proto) 618 continue; 619 620 if (kidx != 0 && kidx != q->kidx) 621 continue; 622 623 if (IS_IP6_FLOW_ID(pkt)) { 624 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 625 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 626 pkt->src_port == q->id.src_port && 627 pkt->dst_port == q->id.dst_port) { 628 dir = MATCH_FORWARD; 629 break; 630 } 631 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 632 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 633 pkt->src_port == q->id.dst_port && 634 pkt->dst_port == q->id.src_port) { 635 dir = MATCH_REVERSE; 636 break; 637 } 638 } else { 639 if (pkt->src_ip == q->id.src_ip && 640 pkt->dst_ip == q->id.dst_ip && 641 pkt->src_port == q->id.src_port && 642 pkt->dst_port == q->id.dst_port) { 643 dir = MATCH_FORWARD; 644 break; 645 } 646 if (pkt->src_ip == q->id.dst_ip && 647 pkt->dst_ip == q->id.src_ip && 648 pkt->src_port == q->id.dst_port && 649 pkt->dst_port == q->id.src_port) { 650 dir = MATCH_REVERSE; 651 break; 652 } 653 } 654 } 655 if (q == NULL) 656 goto done; /* q = NULL, not found */ 657 658 if (prev != NULL) { /* found and not in front */ 659 prev->next = q->next; 660 q->next = V_ipfw_dyn_v[i].head; 661 V_ipfw_dyn_v[i].head = q; 662 } 663 664 /* update state according to flags */ 665 dyn_update_proto_state(q, pkt, ulp, dir); 666done: 667 if (match_direction != NULL) 668 *match_direction = dir; 669 return (q); 670} 671 672struct ip_fw * 673ipfw_dyn_lookup_state(const struct ipfw_flow_id *pkt, const void *ulp, 674 int pktlen, int *match_direction, uint16_t kidx) 675{ 676 struct ip_fw *rule; 677 ipfw_dyn_rule *q; 678 int i; 679 680 i = hash_packet(pkt, V_curr_dyn_buckets); 681 682 IPFW_BUCK_LOCK(i); 683 q = lookup_dyn_rule_locked(pkt, ulp, i, match_direction, kidx); 684 if (q == NULL) 685 rule = NULL; 686 else { 687 rule = q->rule; 688 IPFW_INC_DYN_COUNTER(q, pktlen); 689 } 690 IPFW_BUCK_UNLOCK(i); 691 return (rule); 692} 693 694static int 695resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 696{ 697 int i, k, nbuckets_old; 698 ipfw_dyn_rule *q; 699 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 700 701 /* Check if given number is power of 2 and less than 64k */ 702 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 703 return 1; 704 705 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 706 V_curr_dyn_buckets, nbuckets); 707 708 /* Allocate and initialize new hash */ 709 dyn_v = malloc(nbuckets * sizeof(*dyn_v), M_IPFW, 710 M_WAITOK | M_ZERO); 711 712 for (i = 0 ; i < nbuckets; i++) 713 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 714 715 /* 716 * Call upper half lock, as get_map() do to ease 717 * read-only access to dynamic rules hash from sysctl 718 */ 719 IPFW_UH_WLOCK(chain); 720 721 /* 722 * Acquire chain write lock to permit hash access 723 * for main traffic path without additional locks 724 */ 725 IPFW_WLOCK(chain); 726 727 /* Save old values */ 728 nbuckets_old = V_curr_dyn_buckets; 729 dyn_v_old = V_ipfw_dyn_v; 730 731 /* Skip relinking if array is not set up */ 732 if (V_ipfw_dyn_v == NULL) 733 V_curr_dyn_buckets = 0; 734 735 /* Re-link all dynamic states */ 736 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 737 while (V_ipfw_dyn_v[i].head != NULL) { 738 /* Remove from current chain */ 739 q = V_ipfw_dyn_v[i].head; 740 V_ipfw_dyn_v[i].head = q->next; 741 742 /* Get new hash value */ 743 k = hash_packet(&q->id, nbuckets); 744 q->bucket = k; 745 /* Add to the new head */ 746 q->next = dyn_v[k].head; 747 dyn_v[k].head = q; 748 } 749 } 750 751 /* Update current pointers/buckets values */ 752 V_curr_dyn_buckets = nbuckets; 753 V_ipfw_dyn_v = dyn_v; 754 755 IPFW_WUNLOCK(chain); 756 757 IPFW_UH_WUNLOCK(chain); 758 759 /* Start periodic callout on initial creation */ 760 if (dyn_v_old == NULL) { 761 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 762 return (0); 763 } 764 765 /* Destroy all mutexes */ 766 for (i = 0 ; i < nbuckets_old ; i++) 767 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 768 769 /* Free old hash */ 770 free(dyn_v_old, M_IPFW); 771 772 return 0; 773} 774 775/** 776 * Install state of type 'type' for a dynamic session. 777 * The hash table contains two type of rules: 778 * - regular rules (O_KEEP_STATE) 779 * - rules for sessions with limited number of sess per user 780 * (O_LIMIT). When they are created, the parent is 781 * increased by 1, and decreased on delete. In this case, 782 * the third parameter is the parent rule and not the chain. 783 * - "parent" rules for the above (O_LIMIT_PARENT). 784 */ 785static ipfw_dyn_rule * 786add_dyn_rule(const struct ipfw_flow_id *id, int i, uint8_t dyn_type, 787 struct ip_fw *rule, uint16_t kidx) 788{ 789 ipfw_dyn_rule *r; 790 791 IPFW_BUCK_ASSERT(i); 792 793 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 794 if (r == NULL) { 795 if (last_log != time_uptime) { 796 last_log = time_uptime; 797 log(LOG_DEBUG, 798 "ipfw: Cannot allocate dynamic state, " 799 "consider increasing net.inet.ip.fw.dyn_max\n"); 800 } 801 return NULL; 802 } 803 ipfw_dyn_count++; 804 805 /* 806 * refcount on parent is already incremented, so 807 * it is safe to use parent unlocked. 808 */ 809 if (dyn_type == O_LIMIT) { 810 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 811 if ( parent->dyn_type != O_LIMIT_PARENT) 812 panic("invalid parent"); 813 r->parent = parent; 814 rule = parent->rule; 815 } 816 817 r->id = *id; 818 r->expire = time_uptime + V_dyn_syn_lifetime; 819 r->rule = rule; 820 r->dyn_type = dyn_type; 821 IPFW_ZERO_DYN_COUNTER(r); 822 r->count = 0; 823 r->kidx = kidx; 824 r->bucket = i; 825 r->next = V_ipfw_dyn_v[i].head; 826 V_ipfw_dyn_v[i].head = r; 827 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 828 return r; 829} 830 831/** 832 * lookup dynamic parent rule using pkt and rule as search keys. 833 * If the lookup fails, then install one. 834 */ 835static ipfw_dyn_rule * 836lookup_dyn_parent(const struct ipfw_flow_id *pkt, int *pindex, 837 struct ip_fw *rule, uint16_t kidx) 838{ 839 ipfw_dyn_rule *q; 840 int i, is_v6; 841 842 is_v6 = IS_IP6_FLOW_ID(pkt); 843 i = hash_packet( pkt, V_curr_dyn_buckets ); 844 *pindex = i; 845 IPFW_BUCK_LOCK(i); 846 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 847 if (q->dyn_type == O_LIMIT_PARENT && 848 kidx == q->kidx && 849 rule == q->rule && 850 pkt->proto == q->id.proto && 851 pkt->src_port == q->id.src_port && 852 pkt->dst_port == q->id.dst_port && 853 ( 854 (is_v6 && 855 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 856 &(q->id.src_ip6)) && 857 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 858 &(q->id.dst_ip6))) || 859 (!is_v6 && 860 pkt->src_ip == q->id.src_ip && 861 pkt->dst_ip == q->id.dst_ip) 862 ) 863 ) { 864 q->expire = time_uptime + V_dyn_short_lifetime; 865 DEB(print_dyn_rule(pkt, q->dyn_type, 866 "lookup_dyn_parent found", "");) 867 return q; 868 } 869 870 /* Add virtual limiting rule */ 871 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule, kidx); 872} 873 874/** 875 * Install dynamic state for rule type cmd->o.opcode 876 * 877 * Returns 1 (failure) if state is not installed because of errors or because 878 * session limitations are enforced. 879 */ 880int 881ipfw_dyn_install_state(struct ip_fw_chain *chain, struct ip_fw *rule, 882 ipfw_insn_limit *cmd, struct ip_fw_args *args, uint32_t tablearg) 883{ 884 ipfw_dyn_rule *q; 885 int i; 886 887 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", 888 (cmd->o.arg1 == 0 ? "": DYN_STATE_OBJ(chain, &cmd->o)->name));) 889 890 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 891 892 IPFW_BUCK_LOCK(i); 893 894 q = lookup_dyn_rule_locked(&args->f_id, NULL, i, NULL, cmd->o.arg1); 895 if (q != NULL) { /* should never occur */ 896 DEB( 897 if (last_log != time_uptime) { 898 last_log = time_uptime; 899 printf("ipfw: %s: entry already present, done\n", 900 __func__); 901 }) 902 IPFW_BUCK_UNLOCK(i); 903 return (0); 904 } 905 906 /* 907 * State limiting is done via uma(9) zone limiting. 908 * Save pointer to newly-installed rule and reject 909 * packet if add_dyn_rule() returned NULL. 910 * Note q is currently set to NULL. 911 */ 912 913 switch (cmd->o.opcode) { 914 case O_KEEP_STATE: /* bidir rule */ 915 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule, 916 cmd->o.arg1); 917 break; 918 919 case O_LIMIT: { /* limit number of sessions */ 920 struct ipfw_flow_id id; 921 ipfw_dyn_rule *parent; 922 uint32_t conn_limit; 923 uint16_t limit_mask = cmd->limit_mask; 924 int pindex; 925 926 conn_limit = IP_FW_ARG_TABLEARG(chain, cmd->conn_limit, limit); 927 928 DEB( 929 if (cmd->conn_limit == IP_FW_TARG) 930 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 931 "(tablearg)\n", __func__, conn_limit); 932 else 933 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 934 __func__, conn_limit); 935 ) 936 937 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 938 id.proto = args->f_id.proto; 939 id.addr_type = args->f_id.addr_type; 940 id.fib = M_GETFIB(args->m); 941 942 if (IS_IP6_FLOW_ID (&(args->f_id))) { 943 bzero(&id.src_ip6, sizeof(id.src_ip6)); 944 bzero(&id.dst_ip6, sizeof(id.dst_ip6)); 945 946 if (limit_mask & DYN_SRC_ADDR) 947 id.src_ip6 = args->f_id.src_ip6; 948 if (limit_mask & DYN_DST_ADDR) 949 id.dst_ip6 = args->f_id.dst_ip6; 950 } else { 951 if (limit_mask & DYN_SRC_ADDR) 952 id.src_ip = args->f_id.src_ip; 953 if (limit_mask & DYN_DST_ADDR) 954 id.dst_ip = args->f_id.dst_ip; 955 } 956 if (limit_mask & DYN_SRC_PORT) 957 id.src_port = args->f_id.src_port; 958 if (limit_mask & DYN_DST_PORT) 959 id.dst_port = args->f_id.dst_port; 960 961 /* 962 * We have to release lock for previous bucket to 963 * avoid possible deadlock 964 */ 965 IPFW_BUCK_UNLOCK(i); 966 967 parent = lookup_dyn_parent(&id, &pindex, rule, cmd->o.arg1); 968 if (parent == NULL) { 969 printf("ipfw: %s: add parent failed\n", __func__); 970 IPFW_BUCK_UNLOCK(pindex); 971 return (1); 972 } 973 974 if (parent->count >= conn_limit) { 975 if (V_fw_verbose && last_log != time_uptime) { 976 last_log = time_uptime; 977 char sbuf[24]; 978 last_log = time_uptime; 979 snprintf(sbuf, sizeof(sbuf), 980 "%d drop session", 981 parent->rule->rulenum); 982 print_dyn_rule_flags(&args->f_id, 983 cmd->o.opcode, 984 LOG_SECURITY | LOG_DEBUG, 985 sbuf, "too many entries"); 986 } 987 IPFW_BUCK_UNLOCK(pindex); 988 return (1); 989 } 990 /* Increment counter on parent */ 991 parent->count++; 992 IPFW_BUCK_UNLOCK(pindex); 993 994 IPFW_BUCK_LOCK(i); 995 q = add_dyn_rule(&args->f_id, i, O_LIMIT, 996 (struct ip_fw *)parent, cmd->o.arg1); 997 if (q == NULL) { 998 /* Decrement index and notify caller */ 999 IPFW_BUCK_UNLOCK(i); 1000 IPFW_BUCK_LOCK(pindex); 1001 parent->count--; 1002 IPFW_BUCK_UNLOCK(pindex); 1003 return (1); 1004 } 1005 break; 1006 } 1007 default: 1008 printf("ipfw: %s: unknown dynamic rule type %u\n", 1009 __func__, cmd->o.opcode); 1010 } 1011 1012 if (q == NULL) { 1013 IPFW_BUCK_UNLOCK(i); 1014 return (1); /* Notify caller about failure */ 1015 } 1016 1017 dyn_update_proto_state(q, &args->f_id, NULL, MATCH_FORWARD); 1018 IPFW_BUCK_UNLOCK(i); 1019 return (0); 1020} 1021 1022/* 1023 * Queue keepalive packets for given dynamic rule 1024 */ 1025static struct mbuf ** 1026ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 1027{ 1028 struct mbuf *m_rev, *m_fwd; 1029 1030 m_rev = (q->state & ACK_REV) ? NULL : 1031 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 1032 m_fwd = (q->state & ACK_FWD) ? NULL : 1033 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 1034 1035 if (m_rev != NULL) { 1036 *mtailp = m_rev; 1037 mtailp = &(*mtailp)->m_nextpkt; 1038 } 1039 if (m_fwd != NULL) { 1040 *mtailp = m_fwd; 1041 mtailp = &(*mtailp)->m_nextpkt; 1042 } 1043 1044 return (mtailp); 1045} 1046 1047/* 1048 * This procedure is used to perform various maintenance 1049 * on dynamic hash list. Currently it is called every second. 1050 */ 1051static void 1052ipfw_dyn_tick(void * vnetx) 1053{ 1054 struct ip_fw_chain *chain; 1055 int check_ka = 0; 1056#ifdef VIMAGE 1057 struct vnet *vp = vnetx; 1058#endif 1059 1060 CURVNET_SET(vp); 1061 1062 chain = &V_layer3_chain; 1063 1064 /* Run keepalive checks every keepalive_period iff ka is enabled */ 1065 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 1066 (V_dyn_keepalive != 0)) { 1067 V_dyn_keepalive_last = time_uptime; 1068 check_ka = 1; 1069 } 1070 1071 check_dyn_rules(chain, NULL, check_ka, 1); 1072 1073 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 1074 1075 CURVNET_RESTORE(); 1076} 1077 1078 1079/* 1080 * Walk through all dynamic states doing generic maintenance: 1081 * 1) free expired states 1082 * 2) free all states based on deleted rule / set 1083 * 3) send keepalives for states if needed 1084 * 1085 * @chain - pointer to current ipfw rules chain 1086 * @rule - delete all states originated by given rule if != NULL 1087 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1088 * @check_ka - perform checking/sending keepalives 1089 * @timer - indicate call from timer routine. 1090 * 1091 * Timer routine must call this function unlocked to permit 1092 * sending keepalives/resizing table. 1093 * 1094 * Others has to call function with IPFW_UH_WLOCK held. 1095 * Additionally, function assume that dynamic rule/set is 1096 * ALREADY deleted so no new states can be generated by 1097 * 'deleted' rules. 1098 * 1099 * Write lock is needed to ensure that unused parent rules 1100 * are not freed by other instance (see stage 2, 3) 1101 */ 1102static void 1103check_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt, 1104 int check_ka, int timer) 1105{ 1106 struct mbuf *m0, *m, *mnext, **mtailp; 1107 struct ip *h; 1108 int i, dyn_count, new_buckets = 0, max_buckets; 1109 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1110 ipfw_dyn_rule *q, *q_prev, *q_next; 1111 ipfw_dyn_rule *exp_head, **exptailp; 1112 ipfw_dyn_rule *exp_lhead, **expltailp; 1113 1114 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1115 __func__)); 1116 1117 /* Avoid possible LOR */ 1118 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1119 __func__)); 1120 1121 /* 1122 * Do not perform any checks if we currently have no dynamic states 1123 */ 1124 if (DYN_COUNT == 0) 1125 return; 1126 1127 /* Expired states */ 1128 exp_head = NULL; 1129 exptailp = &exp_head; 1130 1131 /* Expired limit states */ 1132 exp_lhead = NULL; 1133 expltailp = &exp_lhead; 1134 1135 /* 1136 * We make a chain of packets to go out here -- not deferring 1137 * until after we drop the IPFW dynamic rule lock would result 1138 * in a lock order reversal with the normal packet input -> ipfw 1139 * call stack. 1140 */ 1141 m0 = NULL; 1142 mtailp = &m0; 1143 1144 /* Protect from hash resizing */ 1145 if (timer != 0) 1146 IPFW_UH_WLOCK(chain); 1147 else 1148 IPFW_UH_WLOCK_ASSERT(chain); 1149 1150#define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1151 1152 /* Stage 1: perform requested deletion */ 1153 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1154 IPFW_BUCK_LOCK(i); 1155 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1156 /* account every rule */ 1157 total++; 1158 1159 /* Skip parent rules at all */ 1160 if (q->dyn_type == O_LIMIT_PARENT) { 1161 parents++; 1162 NEXT_RULE(); 1163 } 1164 1165 /* 1166 * Remove rules which are: 1167 * 1) expired 1168 * 2) matches deletion range 1169 */ 1170 if ((TIME_LEQ(q->expire, time_uptime)) || 1171 (rt != NULL && ipfw_match_range(q->rule, rt))) { 1172 if (TIME_LE(time_uptime, q->expire) && 1173 q->dyn_type == O_KEEP_STATE && 1174 V_dyn_keep_states != 0) { 1175 /* 1176 * Do not delete state if 1177 * it is not expired and 1178 * dyn_keep_states is ON. 1179 * However we need to re-link it 1180 * to any other stable rule 1181 */ 1182 q->rule = chain->default_rule; 1183 NEXT_RULE(); 1184 } 1185 1186 /* Unlink q from current list */ 1187 q_next = q->next; 1188 if (q == V_ipfw_dyn_v[i].head) 1189 V_ipfw_dyn_v[i].head = q_next; 1190 else 1191 q_prev->next = q_next; 1192 1193 q->next = NULL; 1194 1195 /* queue q to expire list */ 1196 if (q->dyn_type != O_LIMIT) { 1197 *exptailp = q; 1198 exptailp = &(*exptailp)->next; 1199 DEB(print_dyn_rule(&q->id, q->dyn_type, 1200 "unlink entry", "left"); 1201 ) 1202 } else { 1203 /* Separate list for limit rules */ 1204 *expltailp = q; 1205 expltailp = &(*expltailp)->next; 1206 expired_limits++; 1207 DEB(print_dyn_rule(&q->id, q->dyn_type, 1208 "unlink limit entry", "left"); 1209 ) 1210 } 1211 1212 q = q_next; 1213 expired++; 1214 continue; 1215 } 1216 1217 /* 1218 * Check if we need to send keepalive: 1219 * we need to ensure if is time to do KA, 1220 * this is established TCP session, and 1221 * expire time is within keepalive interval 1222 */ 1223 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1224 ((q->state & BOTH_SYN) == BOTH_SYN) && 1225 (TIME_LEQ(q->expire, time_uptime + 1226 V_dyn_keepalive_interval))) 1227 mtailp = ipfw_dyn_send_ka(mtailp, q); 1228 1229 NEXT_RULE(); 1230 } 1231 IPFW_BUCK_UNLOCK(i); 1232 } 1233 1234 /* Stage 2: decrement counters from O_LIMIT parents */ 1235 if (expired_limits != 0) { 1236 /* 1237 * XXX: Note that deleting set with more than one 1238 * heavily-used LIMIT rules can result in overwhelming 1239 * locking due to lack of per-hash value sorting 1240 * 1241 * We should probably think about: 1242 * 1) pre-allocating hash of size, say, 1243 * MAX(16, V_curr_dyn_buckets / 1024) 1244 * 2) checking if expired_limits is large enough 1245 * 3) If yes, init hash (or its part), re-link 1246 * current list and start decrementing procedure in 1247 * each bucket separately 1248 */ 1249 1250 /* 1251 * Small optimization: do not unlock bucket until 1252 * we see the next item resides in different bucket 1253 */ 1254 if (exp_lhead != NULL) { 1255 i = exp_lhead->parent->bucket; 1256 IPFW_BUCK_LOCK(i); 1257 } 1258 for (q = exp_lhead; q != NULL; q = q->next) { 1259 if (i != q->parent->bucket) { 1260 IPFW_BUCK_UNLOCK(i); 1261 i = q->parent->bucket; 1262 IPFW_BUCK_LOCK(i); 1263 } 1264 1265 /* Decrease parent refcount */ 1266 q->parent->count--; 1267 } 1268 if (exp_lhead != NULL) 1269 IPFW_BUCK_UNLOCK(i); 1270 } 1271 1272 /* 1273 * We protectet ourselves from unused parent deletion 1274 * (from the timer function) by holding UH write lock. 1275 */ 1276 1277 /* Stage 3: remove unused parent rules */ 1278 if ((parents != 0) && (expired != 0)) { 1279 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1280 IPFW_BUCK_LOCK(i); 1281 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1282 if (q->dyn_type != O_LIMIT_PARENT) 1283 NEXT_RULE(); 1284 1285 if (q->count != 0) 1286 NEXT_RULE(); 1287 1288 /* Parent rule without consumers */ 1289 1290 /* Unlink q from current list */ 1291 q_next = q->next; 1292 if (q == V_ipfw_dyn_v[i].head) 1293 V_ipfw_dyn_v[i].head = q_next; 1294 else 1295 q_prev->next = q_next; 1296 1297 q->next = NULL; 1298 1299 /* Add to expired list */ 1300 *exptailp = q; 1301 exptailp = &(*exptailp)->next; 1302 1303 DEB(print_dyn_rule(&q->id, q->dyn_type, 1304 "unlink parent entry", "left"); 1305 ) 1306 1307 expired++; 1308 1309 q = q_next; 1310 } 1311 IPFW_BUCK_UNLOCK(i); 1312 } 1313 } 1314 1315#undef NEXT_RULE 1316 1317 if (timer != 0) { 1318 /* 1319 * Check if we need to resize hash: 1320 * if current number of states exceeds number of buckes in hash, 1321 * grow hash size to the minimum power of 2 which is bigger than 1322 * current states count. Limit hash size by 64k. 1323 */ 1324 max_buckets = (V_dyn_buckets_max > 65536) ? 1325 65536 : V_dyn_buckets_max; 1326 1327 dyn_count = DYN_COUNT; 1328 1329 if ((dyn_count > V_curr_dyn_buckets * 2) && 1330 (dyn_count < max_buckets)) { 1331 new_buckets = V_curr_dyn_buckets; 1332 while (new_buckets < dyn_count) { 1333 new_buckets *= 2; 1334 1335 if (new_buckets >= max_buckets) 1336 break; 1337 } 1338 } 1339 1340 IPFW_UH_WUNLOCK(chain); 1341 } 1342 1343 /* Finally delete old states ad limits if any */ 1344 for (q = exp_head; q != NULL; q = q_next) { 1345 q_next = q->next; 1346 uma_zfree(V_ipfw_dyn_rule_zone, q); 1347 ipfw_dyn_count--; 1348 } 1349 1350 for (q = exp_lhead; q != NULL; q = q_next) { 1351 q_next = q->next; 1352 uma_zfree(V_ipfw_dyn_rule_zone, q); 1353 ipfw_dyn_count--; 1354 } 1355 1356 /* 1357 * The rest code MUST be called from timer routine only 1358 * without holding any locks 1359 */ 1360 if (timer == 0) 1361 return; 1362 1363 /* Send keepalive packets if any */ 1364 for (m = m0; m != NULL; m = mnext) { 1365 mnext = m->m_nextpkt; 1366 m->m_nextpkt = NULL; 1367 h = mtod(m, struct ip *); 1368 if (h->ip_v == 4) 1369 ip_output(m, NULL, NULL, 0, NULL, NULL); 1370#ifdef INET6 1371 else 1372 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1373#endif 1374 } 1375 1376 /* Run table resize without holding any locks */ 1377 if (new_buckets != 0) 1378 resize_dynamic_table(chain, new_buckets); 1379} 1380 1381/* 1382 * Deletes all dynamic rules originated by given rule or all rules in 1383 * given set. Specify RESVD_SET to indicate set should not be used. 1384 * @chain - pointer to current ipfw rules chain 1385 * @rr - delete all states originated by rules in matched range. 1386 * 1387 * Function has to be called with IPFW_UH_WLOCK held. 1388 * Additionally, function assume that dynamic rule/set is 1389 * ALREADY deleted so no new states can be generated by 1390 * 'deleted' rules. 1391 */ 1392void 1393ipfw_expire_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt) 1394{ 1395 1396 check_dyn_rules(chain, rt, 0, 0); 1397} 1398 1399/* 1400 * Check if rule contains at least one dynamic opcode. 1401 * 1402 * Returns 1 if such opcode is found, 0 otherwise. 1403 */ 1404int 1405ipfw_is_dyn_rule(struct ip_fw *rule) 1406{ 1407 int cmdlen, l; 1408 ipfw_insn *cmd; 1409 1410 l = rule->cmd_len; 1411 cmd = rule->cmd; 1412 cmdlen = 0; 1413 for ( ; l > 0 ; l -= cmdlen, cmd += cmdlen) { 1414 cmdlen = F_LEN(cmd); 1415 1416 switch (cmd->opcode) { 1417 case O_LIMIT: 1418 case O_KEEP_STATE: 1419 case O_PROBE_STATE: 1420 case O_CHECK_STATE: 1421 return (1); 1422 } 1423 } 1424 1425 return (0); 1426} 1427 1428void 1429ipfw_dyn_init(struct ip_fw_chain *chain) 1430{ 1431 1432 V_ipfw_dyn_v = NULL; 1433 V_dyn_buckets_max = 256; /* must be power of 2 */ 1434 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1435 1436 V_dyn_ack_lifetime = 300; 1437 V_dyn_syn_lifetime = 20; 1438 V_dyn_fin_lifetime = 1; 1439 V_dyn_rst_lifetime = 1; 1440 V_dyn_udp_lifetime = 10; 1441 V_dyn_short_lifetime = 5; 1442 1443 V_dyn_keepalive_interval = 20; 1444 V_dyn_keepalive_period = 5; 1445 V_dyn_keepalive = 1; /* do send keepalives */ 1446 V_dyn_keepalive_last = time_uptime; 1447 1448 V_dyn_max = 16384; /* max # of dynamic rules */ 1449 1450 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1451 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1452 UMA_ALIGN_PTR, 0); 1453 1454 /* Enforce limit on dynamic rules */ 1455 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1456 1457 callout_init(&V_ipfw_timeout, 1); 1458 1459 /* 1460 * This can potentially be done on first dynamic rule 1461 * being added to chain. 1462 */ 1463 resize_dynamic_table(chain, V_curr_dyn_buckets); 1464 IPFW_ADD_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes); 1465} 1466 1467void 1468ipfw_dyn_uninit(int pass) 1469{ 1470 int i; 1471 1472 if (pass == 0) { 1473 callout_drain(&V_ipfw_timeout); 1474 return; 1475 } 1476 IPFW_DEL_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes); 1477 1478 if (V_ipfw_dyn_v != NULL) { 1479 /* 1480 * Skip deleting all dynamic states - 1481 * uma_zdestroy() does this more efficiently; 1482 */ 1483 1484 /* Destroy all mutexes */ 1485 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1486 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1487 free(V_ipfw_dyn_v, M_IPFW); 1488 V_ipfw_dyn_v = NULL; 1489 } 1490 1491 uma_zdestroy(V_ipfw_dyn_rule_zone); 1492} 1493 1494#ifdef SYSCTL_NODE 1495/* 1496 * Get/set maximum number of dynamic states in given VNET instance. 1497 */ 1498static int 1499sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1500{ 1501 int error; 1502 unsigned int nstates; 1503 1504 nstates = V_dyn_max; 1505 1506 error = sysctl_handle_int(oidp, &nstates, 0, req); 1507 /* Read operation or some error */ 1508 if ((error != 0) || (req->newptr == NULL)) 1509 return (error); 1510 1511 V_dyn_max = nstates; 1512 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1513 1514 return (0); 1515} 1516 1517/* 1518 * Get current number of dynamic states in given VNET instance. 1519 */ 1520static int 1521sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1522{ 1523 int error; 1524 unsigned int nstates; 1525 1526 nstates = DYN_COUNT; 1527 1528 error = sysctl_handle_int(oidp, &nstates, 0, req); 1529 1530 return (error); 1531} 1532#endif 1533 1534/* 1535 * Returns size of dynamic states in legacy format 1536 */ 1537int 1538ipfw_dyn_len(void) 1539{ 1540 1541 return (V_ipfw_dyn_v == NULL) ? 0 : 1542 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1543} 1544 1545/* 1546 * Returns number of dynamic states. 1547 * Used by dump format v1 (current). 1548 */ 1549int 1550ipfw_dyn_get_count(void) 1551{ 1552 1553 return (V_ipfw_dyn_v == NULL) ? 0 : DYN_COUNT; 1554} 1555 1556static void 1557export_dyn_rule(ipfw_dyn_rule *src, ipfw_dyn_rule *dst) 1558{ 1559 uint16_t rulenum; 1560 1561 rulenum = (uint16_t)src->rule->rulenum; 1562 memcpy(dst, src, sizeof(*src)); 1563 memcpy(&dst->rule, &rulenum, sizeof(rulenum)); 1564 /* 1565 * store set number into high word of 1566 * dst->rule pointer. 1567 */ 1568 memcpy((char *)&dst->rule + sizeof(rulenum), &src->rule->set, 1569 sizeof(src->rule->set)); 1570 /* 1571 * store a non-null value in "next". 1572 * The userland code will interpret a 1573 * NULL here as a marker 1574 * for the last dynamic rule. 1575 */ 1576 memcpy(&dst->next, &dst, sizeof(dst)); 1577 dst->expire = TIME_LEQ(dst->expire, time_uptime) ? 0: 1578 dst->expire - time_uptime; 1579} 1580 1581/* 1582 * Fills int buffer given by @sd with dynamic states. 1583 * Used by dump format v1 (current). 1584 * 1585 * Returns 0 on success. 1586 */ 1587int 1588ipfw_dump_states(struct ip_fw_chain *chain, struct sockopt_data *sd) 1589{ 1590 ipfw_dyn_rule *p; 1591 ipfw_obj_dyntlv *dst, *last; 1592 ipfw_obj_ctlv *ctlv; 1593 int i; 1594 size_t sz; 1595 1596 if (V_ipfw_dyn_v == NULL) 1597 return (0); 1598 1599 IPFW_UH_RLOCK_ASSERT(chain); 1600 1601 ctlv = (ipfw_obj_ctlv *)ipfw_get_sopt_space(sd, sizeof(*ctlv)); 1602 if (ctlv == NULL) 1603 return (ENOMEM); 1604 sz = sizeof(ipfw_obj_dyntlv); 1605 ctlv->head.type = IPFW_TLV_DYNSTATE_LIST; 1606 ctlv->objsize = sz; 1607 last = NULL; 1608 1609 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1610 IPFW_BUCK_LOCK(i); 1611 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1612 dst = (ipfw_obj_dyntlv *)ipfw_get_sopt_space(sd, sz); 1613 if (dst == NULL) { 1614 IPFW_BUCK_UNLOCK(i); 1615 return (ENOMEM); 1616 } 1617 1618 export_dyn_rule(p, &dst->state); 1619 dst->head.length = sz; 1620 dst->head.type = IPFW_TLV_DYN_ENT; 1621 last = dst; 1622 } 1623 IPFW_BUCK_UNLOCK(i); 1624 } 1625 1626 if (last != NULL) /* mark last dynamic rule */ 1627 last->head.flags = IPFW_DF_LAST; 1628 1629 return (0); 1630} 1631 1632/* 1633 * Fill given buffer with dynamic states (legacy format). 1634 * IPFW_UH_RLOCK has to be held while calling. 1635 */ 1636void 1637ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1638{ 1639 ipfw_dyn_rule *p, *last = NULL; 1640 char *bp; 1641 int i; 1642 1643 if (V_ipfw_dyn_v == NULL) 1644 return; 1645 bp = *pbp; 1646 1647 IPFW_UH_RLOCK_ASSERT(chain); 1648 1649 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1650 IPFW_BUCK_LOCK(i); 1651 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1652 if (bp + sizeof *p <= ep) { 1653 ipfw_dyn_rule *dst = 1654 (ipfw_dyn_rule *)bp; 1655 1656 export_dyn_rule(p, dst); 1657 last = dst; 1658 bp += sizeof(ipfw_dyn_rule); 1659 } 1660 } 1661 IPFW_BUCK_UNLOCK(i); 1662 } 1663 1664 if (last != NULL) /* mark last dynamic rule */ 1665 bzero(&last->next, sizeof(last)); 1666 *pbp = bp; 1667} 1668/* end of file */ 1669