ip_fw_dynamic.c revision 317262
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 317262 2017-04-21 17:09:37Z 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(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(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 IPFW_WLOCK(ch); 422 SRV_OBJECT(ch, obj->no.kidx) = obj; 423 IPFW_WUNLOCK(ch); 424 obj->no.refcnt++; 425 *pkidx = obj->no.kidx; 426 IPFW_UH_WUNLOCK(ch); 427 DYN_DEBUG("\tcreated kidx %d", *pkidx); 428 return (0); 429} 430 431static void 432dyn_destroy(struct ip_fw_chain *ch, struct named_object *no) 433{ 434 struct dyn_state_obj *obj; 435 436 IPFW_UH_WLOCK_ASSERT(ch); 437 438 KASSERT(no->refcnt == 1, 439 ("Destroying object '%s' (type %u, idx %u) with refcnt %u", 440 no->name, no->etlv, no->kidx, no->refcnt)); 441 442 DYN_DEBUG("kidx %d", no->kidx); 443 IPFW_WLOCK(ch); 444 obj = SRV_OBJECT(ch, no->kidx); 445 SRV_OBJECT(ch, no->kidx) = NULL; 446 IPFW_WUNLOCK(ch); 447 ipfw_objhash_del(CHAIN_TO_SRV(ch), no); 448 ipfw_objhash_free_idx(CHAIN_TO_SRV(ch), no->kidx); 449 450 free(obj, M_IPFW); 451} 452 453static struct opcode_obj_rewrite dyn_opcodes[] = { 454 { 455 O_KEEP_STATE, IPFW_TLV_STATE_NAME, 456 dyn_classify, dyn_update, 457 dyn_findbyname, dyn_findbykidx, 458 dyn_create, dyn_destroy 459 }, 460 { 461 O_CHECK_STATE, IPFW_TLV_STATE_NAME, 462 dyn_classify, dyn_update, 463 dyn_findbyname, dyn_findbykidx, 464 dyn_create, dyn_destroy 465 }, 466 { 467 O_PROBE_STATE, IPFW_TLV_STATE_NAME, 468 dyn_classify, dyn_update, 469 dyn_findbyname, dyn_findbykidx, 470 dyn_create, dyn_destroy 471 }, 472 { 473 O_LIMIT, IPFW_TLV_STATE_NAME, 474 dyn_classify, dyn_update, 475 dyn_findbyname, dyn_findbykidx, 476 dyn_create, dyn_destroy 477 }, 478}; 479/** 480 * Print customizable flow id description via log(9) facility. 481 */ 482static void 483print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags, 484 char *prefix, char *postfix) 485{ 486 struct in_addr da; 487#ifdef INET6 488 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN]; 489#else 490 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN]; 491#endif 492 493#ifdef INET6 494 if (IS_IP6_FLOW_ID(id)) { 495 ip6_sprintf(src, &id->src_ip6); 496 ip6_sprintf(dst, &id->dst_ip6); 497 } else 498#endif 499 { 500 da.s_addr = htonl(id->src_ip); 501 inet_ntop(AF_INET, &da, src, sizeof(src)); 502 da.s_addr = htonl(id->dst_ip); 503 inet_ntop(AF_INET, &da, dst, sizeof(dst)); 504 } 505 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n", 506 prefix, dyn_type, src, id->src_port, dst, 507 id->dst_port, DYN_COUNT, postfix); 508} 509 510#define print_dyn_rule(id, dtype, prefix, postfix) \ 511 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix) 512 513#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0) 514#define TIME_LE(a,b) ((int)((a)-(b)) < 0) 515 516static void 517dyn_update_proto_state(ipfw_dyn_rule *q, const struct ipfw_flow_id *id, 518 const struct tcphdr *tcp, int dir) 519{ 520 uint32_t ack; 521 u_char flags; 522 523 if (id->proto == IPPROTO_TCP) { 524 flags = id->_flags & (TH_FIN | TH_SYN | TH_RST); 525#define BOTH_SYN (TH_SYN | (TH_SYN << 8)) 526#define BOTH_FIN (TH_FIN | (TH_FIN << 8)) 527#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8)) 528#define ACK_FWD 0x10000 /* fwd ack seen */ 529#define ACK_REV 0x20000 /* rev ack seen */ 530 531 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8); 532 switch (q->state & TCP_FLAGS) { 533 case TH_SYN: /* opening */ 534 q->expire = time_uptime + V_dyn_syn_lifetime; 535 break; 536 537 case BOTH_SYN: /* move to established */ 538 case BOTH_SYN | TH_FIN: /* one side tries to close */ 539 case BOTH_SYN | (TH_FIN << 8): 540#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0) 541 if (tcp == NULL) 542 break; 543 544 ack = ntohl(tcp->th_ack); 545 if (dir == MATCH_FORWARD) { 546 if (q->ack_fwd == 0 || 547 _SEQ_GE(ack, q->ack_fwd)) { 548 q->ack_fwd = ack; 549 q->state |= ACK_FWD; 550 } 551 } else { 552 if (q->ack_rev == 0 || 553 _SEQ_GE(ack, q->ack_rev)) { 554 q->ack_rev = ack; 555 q->state |= ACK_REV; 556 } 557 } 558 if ((q->state & (ACK_FWD | ACK_REV)) == 559 (ACK_FWD | ACK_REV)) { 560 q->expire = time_uptime + V_dyn_ack_lifetime; 561 q->state &= ~(ACK_FWD | ACK_REV); 562 } 563 break; 564 565 case BOTH_SYN | BOTH_FIN: /* both sides closed */ 566 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period) 567 V_dyn_fin_lifetime = 568 V_dyn_keepalive_period - 1; 569 q->expire = time_uptime + V_dyn_fin_lifetime; 570 break; 571 572 default: 573#if 0 574 /* 575 * reset or some invalid combination, but can also 576 * occur if we use keep-state the wrong way. 577 */ 578 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0) 579 printf("invalid state: 0x%x\n", q->state); 580#endif 581 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period) 582 V_dyn_rst_lifetime = 583 V_dyn_keepalive_period - 1; 584 q->expire = time_uptime + V_dyn_rst_lifetime; 585 break; 586 } 587 } else if (id->proto == IPPROTO_UDP) { 588 q->expire = time_uptime + V_dyn_udp_lifetime; 589 } else { 590 /* other protocols */ 591 q->expire = time_uptime + V_dyn_short_lifetime; 592 } 593} 594 595/* 596 * Lookup a dynamic rule, locked version. 597 */ 598static ipfw_dyn_rule * 599lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction, 600 struct tcphdr *tcp, uint16_t kidx) 601{ 602 /* 603 * Stateful ipfw extensions. 604 * Lookup into dynamic session queue. 605 */ 606 ipfw_dyn_rule *prev, *q = NULL; 607 int dir; 608 609 IPFW_BUCK_ASSERT(i); 610 611 dir = MATCH_NONE; 612 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) { 613 if (q->dyn_type == O_LIMIT_PARENT) 614 continue; 615 616 if (pkt->proto != q->id.proto) 617 continue; 618 619 if (kidx != 0 && kidx != q->kidx) 620 continue; 621 622 if (IS_IP6_FLOW_ID(pkt)) { 623 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) && 624 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) && 625 pkt->src_port == q->id.src_port && 626 pkt->dst_port == q->id.dst_port) { 627 dir = MATCH_FORWARD; 628 break; 629 } 630 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) && 631 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) && 632 pkt->src_port == q->id.dst_port && 633 pkt->dst_port == q->id.src_port) { 634 dir = MATCH_REVERSE; 635 break; 636 } 637 } else { 638 if (pkt->src_ip == q->id.src_ip && 639 pkt->dst_ip == q->id.dst_ip && 640 pkt->src_port == q->id.src_port && 641 pkt->dst_port == q->id.dst_port) { 642 dir = MATCH_FORWARD; 643 break; 644 } 645 if (pkt->src_ip == q->id.dst_ip && 646 pkt->dst_ip == q->id.src_ip && 647 pkt->src_port == q->id.dst_port && 648 pkt->dst_port == q->id.src_port) { 649 dir = MATCH_REVERSE; 650 break; 651 } 652 } 653 } 654 if (q == NULL) 655 goto done; /* q = NULL, not found */ 656 657 if (prev != NULL) { /* found and not in front */ 658 prev->next = q->next; 659 q->next = V_ipfw_dyn_v[i].head; 660 V_ipfw_dyn_v[i].head = q; 661 } 662 663 /* update state according to flags */ 664 dyn_update_proto_state(q, pkt, tcp, dir); 665done: 666 if (match_direction != NULL) 667 *match_direction = dir; 668 return (q); 669} 670 671ipfw_dyn_rule * 672ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction, 673 struct tcphdr *tcp, uint16_t kidx) 674{ 675 ipfw_dyn_rule *q; 676 int i; 677 678 i = hash_packet(pkt, V_curr_dyn_buckets); 679 680 IPFW_BUCK_LOCK(i); 681 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp, kidx); 682 if (q == NULL) 683 IPFW_BUCK_UNLOCK(i); 684 /* NB: return table locked when q is not NULL */ 685 return q; 686} 687 688/* 689 * Unlock bucket mtx 690 * @p - pointer to dynamic rule 691 */ 692void 693ipfw_dyn_unlock(ipfw_dyn_rule *q) 694{ 695 696 IPFW_BUCK_UNLOCK(q->bucket); 697} 698 699static int 700resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets) 701{ 702 int i, k, nbuckets_old; 703 ipfw_dyn_rule *q; 704 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old; 705 706 /* Check if given number is power of 2 and less than 64k */ 707 if ((nbuckets > 65536) || (!powerof2(nbuckets))) 708 return 1; 709 710 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__, 711 V_curr_dyn_buckets, nbuckets); 712 713 /* Allocate and initialize new hash */ 714 dyn_v = malloc(nbuckets * sizeof(*dyn_v), M_IPFW, 715 M_WAITOK | M_ZERO); 716 717 for (i = 0 ; i < nbuckets; i++) 718 IPFW_BUCK_LOCK_INIT(&dyn_v[i]); 719 720 /* 721 * Call upper half lock, as get_map() do to ease 722 * read-only access to dynamic rules hash from sysctl 723 */ 724 IPFW_UH_WLOCK(chain); 725 726 /* 727 * Acquire chain write lock to permit hash access 728 * for main traffic path without additional locks 729 */ 730 IPFW_WLOCK(chain); 731 732 /* Save old values */ 733 nbuckets_old = V_curr_dyn_buckets; 734 dyn_v_old = V_ipfw_dyn_v; 735 736 /* Skip relinking if array is not set up */ 737 if (V_ipfw_dyn_v == NULL) 738 V_curr_dyn_buckets = 0; 739 740 /* Re-link all dynamic states */ 741 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 742 while (V_ipfw_dyn_v[i].head != NULL) { 743 /* Remove from current chain */ 744 q = V_ipfw_dyn_v[i].head; 745 V_ipfw_dyn_v[i].head = q->next; 746 747 /* Get new hash value */ 748 k = hash_packet(&q->id, nbuckets); 749 q->bucket = k; 750 /* Add to the new head */ 751 q->next = dyn_v[k].head; 752 dyn_v[k].head = q; 753 } 754 } 755 756 /* Update current pointers/buckets values */ 757 V_curr_dyn_buckets = nbuckets; 758 V_ipfw_dyn_v = dyn_v; 759 760 IPFW_WUNLOCK(chain); 761 762 IPFW_UH_WUNLOCK(chain); 763 764 /* Start periodic callout on initial creation */ 765 if (dyn_v_old == NULL) { 766 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0); 767 return (0); 768 } 769 770 /* Destroy all mutexes */ 771 for (i = 0 ; i < nbuckets_old ; i++) 772 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]); 773 774 /* Free old hash */ 775 free(dyn_v_old, M_IPFW); 776 777 return 0; 778} 779 780/** 781 * Install state of type 'type' for a dynamic session. 782 * The hash table contains two type of rules: 783 * - regular rules (O_KEEP_STATE) 784 * - rules for sessions with limited number of sess per user 785 * (O_LIMIT). When they are created, the parent is 786 * increased by 1, and decreased on delete. In this case, 787 * the third parameter is the parent rule and not the chain. 788 * - "parent" rules for the above (O_LIMIT_PARENT). 789 */ 790static ipfw_dyn_rule * 791add_dyn_rule(struct ipfw_flow_id *id, int i, uint8_t dyn_type, 792 struct ip_fw *rule, uint16_t kidx) 793{ 794 ipfw_dyn_rule *r; 795 796 IPFW_BUCK_ASSERT(i); 797 798 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO); 799 if (r == NULL) { 800 if (last_log != time_uptime) { 801 last_log = time_uptime; 802 log(LOG_DEBUG, 803 "ipfw: Cannot allocate dynamic state, " 804 "consider increasing net.inet.ip.fw.dyn_max\n"); 805 } 806 return NULL; 807 } 808 ipfw_dyn_count++; 809 810 /* 811 * refcount on parent is already incremented, so 812 * it is safe to use parent unlocked. 813 */ 814 if (dyn_type == O_LIMIT) { 815 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule; 816 if ( parent->dyn_type != O_LIMIT_PARENT) 817 panic("invalid parent"); 818 r->parent = parent; 819 rule = parent->rule; 820 } 821 822 r->id = *id; 823 r->expire = time_uptime + V_dyn_syn_lifetime; 824 r->rule = rule; 825 r->dyn_type = dyn_type; 826 IPFW_ZERO_DYN_COUNTER(r); 827 r->count = 0; 828 r->kidx = kidx; 829 r->bucket = i; 830 r->next = V_ipfw_dyn_v[i].head; 831 V_ipfw_dyn_v[i].head = r; 832 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");) 833 return r; 834} 835 836/** 837 * lookup dynamic parent rule using pkt and rule as search keys. 838 * If the lookup fails, then install one. 839 */ 840static ipfw_dyn_rule * 841lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule, 842 uint16_t kidx) 843{ 844 ipfw_dyn_rule *q; 845 int i, is_v6; 846 847 is_v6 = IS_IP6_FLOW_ID(pkt); 848 i = hash_packet( pkt, V_curr_dyn_buckets ); 849 *pindex = i; 850 IPFW_BUCK_LOCK(i); 851 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next) 852 if (q->dyn_type == O_LIMIT_PARENT && 853 kidx == q->kidx && 854 rule == q->rule && 855 pkt->proto == q->id.proto && 856 pkt->src_port == q->id.src_port && 857 pkt->dst_port == q->id.dst_port && 858 ( 859 (is_v6 && 860 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6), 861 &(q->id.src_ip6)) && 862 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6), 863 &(q->id.dst_ip6))) || 864 (!is_v6 && 865 pkt->src_ip == q->id.src_ip && 866 pkt->dst_ip == q->id.dst_ip) 867 ) 868 ) { 869 q->expire = time_uptime + V_dyn_short_lifetime; 870 DEB(print_dyn_rule(pkt, q->dyn_type, 871 "lookup_dyn_parent found", "");) 872 return q; 873 } 874 875 /* Add virtual limiting rule */ 876 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule, kidx); 877} 878 879/** 880 * Install dynamic state for rule type cmd->o.opcode 881 * 882 * Returns 1 (failure) if state is not installed because of errors or because 883 * session limitations are enforced. 884 */ 885int 886ipfw_install_state(struct ip_fw_chain *chain, struct ip_fw *rule, 887 ipfw_insn_limit *cmd, struct ip_fw_args *args, uint32_t tablearg) 888{ 889 ipfw_dyn_rule *q; 890 int i; 891 892 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", 893 (cmd->o.arg1 == 0 ? "": DYN_STATE_OBJ(chain, &cmd->o)->name));) 894 895 i = hash_packet(&args->f_id, V_curr_dyn_buckets); 896 897 IPFW_BUCK_LOCK(i); 898 899 q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL, cmd->o.arg1); 900 if (q != NULL) { /* should never occur */ 901 DEB( 902 if (last_log != time_uptime) { 903 last_log = time_uptime; 904 printf("ipfw: %s: entry already present, done\n", 905 __func__); 906 }) 907 IPFW_BUCK_UNLOCK(i); 908 return (0); 909 } 910 911 /* 912 * State limiting is done via uma(9) zone limiting. 913 * Save pointer to newly-installed rule and reject 914 * packet if add_dyn_rule() returned NULL. 915 * Note q is currently set to NULL. 916 */ 917 918 switch (cmd->o.opcode) { 919 case O_KEEP_STATE: /* bidir rule */ 920 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule, 921 cmd->o.arg1); 922 break; 923 924 case O_LIMIT: { /* limit number of sessions */ 925 struct ipfw_flow_id id; 926 ipfw_dyn_rule *parent; 927 uint32_t conn_limit; 928 uint16_t limit_mask = cmd->limit_mask; 929 int pindex; 930 931 conn_limit = IP_FW_ARG_TABLEARG(chain, cmd->conn_limit, limit); 932 933 DEB( 934 if (cmd->conn_limit == IP_FW_TARG) 935 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u " 936 "(tablearg)\n", __func__, conn_limit); 937 else 938 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n", 939 __func__, conn_limit); 940 ) 941 942 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0; 943 id.proto = args->f_id.proto; 944 id.addr_type = args->f_id.addr_type; 945 id.fib = M_GETFIB(args->m); 946 947 if (IS_IP6_FLOW_ID (&(args->f_id))) { 948 bzero(&id.src_ip6, sizeof(id.src_ip6)); 949 bzero(&id.dst_ip6, sizeof(id.dst_ip6)); 950 951 if (limit_mask & DYN_SRC_ADDR) 952 id.src_ip6 = args->f_id.src_ip6; 953 if (limit_mask & DYN_DST_ADDR) 954 id.dst_ip6 = args->f_id.dst_ip6; 955 } else { 956 if (limit_mask & DYN_SRC_ADDR) 957 id.src_ip = args->f_id.src_ip; 958 if (limit_mask & DYN_DST_ADDR) 959 id.dst_ip = args->f_id.dst_ip; 960 } 961 if (limit_mask & DYN_SRC_PORT) 962 id.src_port = args->f_id.src_port; 963 if (limit_mask & DYN_DST_PORT) 964 id.dst_port = args->f_id.dst_port; 965 966 /* 967 * We have to release lock for previous bucket to 968 * avoid possible deadlock 969 */ 970 IPFW_BUCK_UNLOCK(i); 971 972 parent = lookup_dyn_parent(&id, &pindex, rule, cmd->o.arg1); 973 if (parent == NULL) { 974 printf("ipfw: %s: add parent failed\n", __func__); 975 IPFW_BUCK_UNLOCK(pindex); 976 return (1); 977 } 978 979 if (parent->count >= conn_limit) { 980 if (V_fw_verbose && last_log != time_uptime) { 981 last_log = time_uptime; 982 char sbuf[24]; 983 last_log = time_uptime; 984 snprintf(sbuf, sizeof(sbuf), 985 "%d drop session", 986 parent->rule->rulenum); 987 print_dyn_rule_flags(&args->f_id, 988 cmd->o.opcode, 989 LOG_SECURITY | LOG_DEBUG, 990 sbuf, "too many entries"); 991 } 992 IPFW_BUCK_UNLOCK(pindex); 993 return (1); 994 } 995 /* Increment counter on parent */ 996 parent->count++; 997 IPFW_BUCK_UNLOCK(pindex); 998 999 IPFW_BUCK_LOCK(i); 1000 q = add_dyn_rule(&args->f_id, i, O_LIMIT, 1001 (struct ip_fw *)parent, cmd->o.arg1); 1002 if (q == NULL) { 1003 /* Decrement index and notify caller */ 1004 IPFW_BUCK_UNLOCK(i); 1005 IPFW_BUCK_LOCK(pindex); 1006 parent->count--; 1007 IPFW_BUCK_UNLOCK(pindex); 1008 return (1); 1009 } 1010 break; 1011 } 1012 default: 1013 printf("ipfw: %s: unknown dynamic rule type %u\n", 1014 __func__, cmd->o.opcode); 1015 } 1016 1017 if (q == NULL) { 1018 IPFW_BUCK_UNLOCK(i); 1019 return (1); /* Notify caller about failure */ 1020 } 1021 1022 dyn_update_proto_state(q, &args->f_id, NULL, MATCH_FORWARD); 1023 IPFW_BUCK_UNLOCK(i); 1024 return (0); 1025} 1026 1027/* 1028 * Generate a TCP packet, containing either a RST or a keepalive. 1029 * When flags & TH_RST, we are sending a RST packet, because of a 1030 * "reset" action matched the packet. 1031 * Otherwise we are sending a keepalive, and flags & TH_ 1032 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required 1033 * so that MAC can label the reply appropriately. 1034 */ 1035struct mbuf * 1036ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq, 1037 u_int32_t ack, int flags) 1038{ 1039 struct mbuf *m = NULL; /* stupid compiler */ 1040 int len, dir; 1041 struct ip *h = NULL; /* stupid compiler */ 1042#ifdef INET6 1043 struct ip6_hdr *h6 = NULL; 1044#endif 1045 struct tcphdr *th = NULL; 1046 1047 MGETHDR(m, M_NOWAIT, MT_DATA); 1048 if (m == NULL) 1049 return (NULL); 1050 1051 M_SETFIB(m, id->fib); 1052#ifdef MAC 1053 if (replyto != NULL) 1054 mac_netinet_firewall_reply(replyto, m); 1055 else 1056 mac_netinet_firewall_send(m); 1057#else 1058 (void)replyto; /* don't warn about unused arg */ 1059#endif 1060 1061 switch (id->addr_type) { 1062 case 4: 1063 len = sizeof(struct ip) + sizeof(struct tcphdr); 1064 break; 1065#ifdef INET6 1066 case 6: 1067 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1068 break; 1069#endif 1070 default: 1071 /* XXX: log me?!? */ 1072 FREE_PKT(m); 1073 return (NULL); 1074 } 1075 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN); 1076 1077 m->m_data += max_linkhdr; 1078 m->m_flags |= M_SKIP_FIREWALL; 1079 m->m_pkthdr.len = m->m_len = len; 1080 m->m_pkthdr.rcvif = NULL; 1081 bzero(m->m_data, len); 1082 1083 switch (id->addr_type) { 1084 case 4: 1085 h = mtod(m, struct ip *); 1086 1087 /* prepare for checksum */ 1088 h->ip_p = IPPROTO_TCP; 1089 h->ip_len = htons(sizeof(struct tcphdr)); 1090 if (dir) { 1091 h->ip_src.s_addr = htonl(id->src_ip); 1092 h->ip_dst.s_addr = htonl(id->dst_ip); 1093 } else { 1094 h->ip_src.s_addr = htonl(id->dst_ip); 1095 h->ip_dst.s_addr = htonl(id->src_ip); 1096 } 1097 1098 th = (struct tcphdr *)(h + 1); 1099 break; 1100#ifdef INET6 1101 case 6: 1102 h6 = mtod(m, struct ip6_hdr *); 1103 1104 /* prepare for checksum */ 1105 h6->ip6_nxt = IPPROTO_TCP; 1106 h6->ip6_plen = htons(sizeof(struct tcphdr)); 1107 if (dir) { 1108 h6->ip6_src = id->src_ip6; 1109 h6->ip6_dst = id->dst_ip6; 1110 } else { 1111 h6->ip6_src = id->dst_ip6; 1112 h6->ip6_dst = id->src_ip6; 1113 } 1114 1115 th = (struct tcphdr *)(h6 + 1); 1116 break; 1117#endif 1118 } 1119 1120 if (dir) { 1121 th->th_sport = htons(id->src_port); 1122 th->th_dport = htons(id->dst_port); 1123 } else { 1124 th->th_sport = htons(id->dst_port); 1125 th->th_dport = htons(id->src_port); 1126 } 1127 th->th_off = sizeof(struct tcphdr) >> 2; 1128 1129 if (flags & TH_RST) { 1130 if (flags & TH_ACK) { 1131 th->th_seq = htonl(ack); 1132 th->th_flags = TH_RST; 1133 } else { 1134 if (flags & TH_SYN) 1135 seq++; 1136 th->th_ack = htonl(seq); 1137 th->th_flags = TH_RST | TH_ACK; 1138 } 1139 } else { 1140 /* 1141 * Keepalive - use caller provided sequence numbers 1142 */ 1143 th->th_seq = htonl(seq); 1144 th->th_ack = htonl(ack); 1145 th->th_flags = TH_ACK; 1146 } 1147 1148 switch (id->addr_type) { 1149 case 4: 1150 th->th_sum = in_cksum(m, len); 1151 1152 /* finish the ip header */ 1153 h->ip_v = 4; 1154 h->ip_hl = sizeof(*h) >> 2; 1155 h->ip_tos = IPTOS_LOWDELAY; 1156 h->ip_off = htons(0); 1157 h->ip_len = htons(len); 1158 h->ip_ttl = V_ip_defttl; 1159 h->ip_sum = 0; 1160 break; 1161#ifdef INET6 1162 case 6: 1163 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6), 1164 sizeof(struct tcphdr)); 1165 1166 /* finish the ip6 header */ 1167 h6->ip6_vfc |= IPV6_VERSION; 1168 h6->ip6_hlim = IPV6_DEFHLIM; 1169 break; 1170#endif 1171 } 1172 1173 return (m); 1174} 1175 1176/* 1177 * Queue keepalive packets for given dynamic rule 1178 */ 1179static struct mbuf ** 1180ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q) 1181{ 1182 struct mbuf *m_rev, *m_fwd; 1183 1184 m_rev = (q->state & ACK_REV) ? NULL : 1185 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN); 1186 m_fwd = (q->state & ACK_FWD) ? NULL : 1187 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0); 1188 1189 if (m_rev != NULL) { 1190 *mtailp = m_rev; 1191 mtailp = &(*mtailp)->m_nextpkt; 1192 } 1193 if (m_fwd != NULL) { 1194 *mtailp = m_fwd; 1195 mtailp = &(*mtailp)->m_nextpkt; 1196 } 1197 1198 return (mtailp); 1199} 1200 1201/* 1202 * This procedure is used to perform various maintenance 1203 * on dynamic hash list. Currently it is called every second. 1204 */ 1205static void 1206ipfw_dyn_tick(void * vnetx) 1207{ 1208 struct ip_fw_chain *chain; 1209 int check_ka = 0; 1210#ifdef VIMAGE 1211 struct vnet *vp = vnetx; 1212#endif 1213 1214 CURVNET_SET(vp); 1215 1216 chain = &V_layer3_chain; 1217 1218 /* Run keepalive checks every keepalive_period iff ka is enabled */ 1219 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) && 1220 (V_dyn_keepalive != 0)) { 1221 V_dyn_keepalive_last = time_uptime; 1222 check_ka = 1; 1223 } 1224 1225 check_dyn_rules(chain, NULL, check_ka, 1); 1226 1227 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0); 1228 1229 CURVNET_RESTORE(); 1230} 1231 1232 1233/* 1234 * Walk through all dynamic states doing generic maintenance: 1235 * 1) free expired states 1236 * 2) free all states based on deleted rule / set 1237 * 3) send keepalives for states if needed 1238 * 1239 * @chain - pointer to current ipfw rules chain 1240 * @rule - delete all states originated by given rule if != NULL 1241 * @set - delete all states originated by any rule in set @set if != RESVD_SET 1242 * @check_ka - perform checking/sending keepalives 1243 * @timer - indicate call from timer routine. 1244 * 1245 * Timer routine must call this function unlocked to permit 1246 * sending keepalives/resizing table. 1247 * 1248 * Others has to call function with IPFW_UH_WLOCK held. 1249 * Additionally, function assume that dynamic rule/set is 1250 * ALREADY deleted so no new states can be generated by 1251 * 'deleted' rules. 1252 * 1253 * Write lock is needed to ensure that unused parent rules 1254 * are not freed by other instance (see stage 2, 3) 1255 */ 1256static void 1257check_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt, 1258 int check_ka, int timer) 1259{ 1260 struct mbuf *m0, *m, *mnext, **mtailp; 1261 struct ip *h; 1262 int i, dyn_count, new_buckets = 0, max_buckets; 1263 int expired = 0, expired_limits = 0, parents = 0, total = 0; 1264 ipfw_dyn_rule *q, *q_prev, *q_next; 1265 ipfw_dyn_rule *exp_head, **exptailp; 1266 ipfw_dyn_rule *exp_lhead, **expltailp; 1267 1268 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated", 1269 __func__)); 1270 1271 /* Avoid possible LOR */ 1272 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held", 1273 __func__)); 1274 1275 /* 1276 * Do not perform any checks if we currently have no dynamic states 1277 */ 1278 if (DYN_COUNT == 0) 1279 return; 1280 1281 /* Expired states */ 1282 exp_head = NULL; 1283 exptailp = &exp_head; 1284 1285 /* Expired limit states */ 1286 exp_lhead = NULL; 1287 expltailp = &exp_lhead; 1288 1289 /* 1290 * We make a chain of packets to go out here -- not deferring 1291 * until after we drop the IPFW dynamic rule lock would result 1292 * in a lock order reversal with the normal packet input -> ipfw 1293 * call stack. 1294 */ 1295 m0 = NULL; 1296 mtailp = &m0; 1297 1298 /* Protect from hash resizing */ 1299 if (timer != 0) 1300 IPFW_UH_WLOCK(chain); 1301 else 1302 IPFW_UH_WLOCK_ASSERT(chain); 1303 1304#define NEXT_RULE() { q_prev = q; q = q->next ; continue; } 1305 1306 /* Stage 1: perform requested deletion */ 1307 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1308 IPFW_BUCK_LOCK(i); 1309 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) { 1310 /* account every rule */ 1311 total++; 1312 1313 /* Skip parent rules at all */ 1314 if (q->dyn_type == O_LIMIT_PARENT) { 1315 parents++; 1316 NEXT_RULE(); 1317 } 1318 1319 /* 1320 * Remove rules which are: 1321 * 1) expired 1322 * 2) matches deletion range 1323 */ 1324 if ((TIME_LEQ(q->expire, time_uptime)) || 1325 (rt != NULL && ipfw_match_range(q->rule, rt))) { 1326 if (TIME_LE(time_uptime, q->expire) && 1327 q->dyn_type == O_KEEP_STATE && 1328 V_dyn_keep_states != 0) { 1329 /* 1330 * Do not delete state if 1331 * it is not expired and 1332 * dyn_keep_states is ON. 1333 * However we need to re-link it 1334 * to any other stable rule 1335 */ 1336 q->rule = chain->default_rule; 1337 NEXT_RULE(); 1338 } 1339 1340 /* Unlink q from current list */ 1341 q_next = q->next; 1342 if (q == V_ipfw_dyn_v[i].head) 1343 V_ipfw_dyn_v[i].head = q_next; 1344 else 1345 q_prev->next = q_next; 1346 1347 q->next = NULL; 1348 1349 /* queue q to expire list */ 1350 if (q->dyn_type != O_LIMIT) { 1351 *exptailp = q; 1352 exptailp = &(*exptailp)->next; 1353 DEB(print_dyn_rule(&q->id, q->dyn_type, 1354 "unlink entry", "left"); 1355 ) 1356 } else { 1357 /* Separate list for limit rules */ 1358 *expltailp = q; 1359 expltailp = &(*expltailp)->next; 1360 expired_limits++; 1361 DEB(print_dyn_rule(&q->id, q->dyn_type, 1362 "unlink limit entry", "left"); 1363 ) 1364 } 1365 1366 q = q_next; 1367 expired++; 1368 continue; 1369 } 1370 1371 /* 1372 * Check if we need to send keepalive: 1373 * we need to ensure if is time to do KA, 1374 * this is established TCP session, and 1375 * expire time is within keepalive interval 1376 */ 1377 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) && 1378 ((q->state & BOTH_SYN) == BOTH_SYN) && 1379 (TIME_LEQ(q->expire, time_uptime + 1380 V_dyn_keepalive_interval))) 1381 mtailp = ipfw_dyn_send_ka(mtailp, q); 1382 1383 NEXT_RULE(); 1384 } 1385 IPFW_BUCK_UNLOCK(i); 1386 } 1387 1388 /* Stage 2: decrement counters from O_LIMIT parents */ 1389 if (expired_limits != 0) { 1390 /* 1391 * XXX: Note that deleting set with more than one 1392 * heavily-used LIMIT rules can result in overwhelming 1393 * locking due to lack of per-hash value sorting 1394 * 1395 * We should probably think about: 1396 * 1) pre-allocating hash of size, say, 1397 * MAX(16, V_curr_dyn_buckets / 1024) 1398 * 2) checking if expired_limits is large enough 1399 * 3) If yes, init hash (or its part), re-link 1400 * current list and start decrementing procedure in 1401 * each bucket separately 1402 */ 1403 1404 /* 1405 * Small optimization: do not unlock bucket until 1406 * we see the next item resides in different bucket 1407 */ 1408 if (exp_lhead != NULL) { 1409 i = exp_lhead->parent->bucket; 1410 IPFW_BUCK_LOCK(i); 1411 } 1412 for (q = exp_lhead; q != NULL; q = q->next) { 1413 if (i != q->parent->bucket) { 1414 IPFW_BUCK_UNLOCK(i); 1415 i = q->parent->bucket; 1416 IPFW_BUCK_LOCK(i); 1417 } 1418 1419 /* Decrease parent refcount */ 1420 q->parent->count--; 1421 } 1422 if (exp_lhead != NULL) 1423 IPFW_BUCK_UNLOCK(i); 1424 } 1425 1426 /* 1427 * We protectet ourselves from unused parent deletion 1428 * (from the timer function) by holding UH write lock. 1429 */ 1430 1431 /* Stage 3: remove unused parent rules */ 1432 if ((parents != 0) && (expired != 0)) { 1433 for (i = 0 ; i < V_curr_dyn_buckets ; i++) { 1434 IPFW_BUCK_LOCK(i); 1435 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) { 1436 if (q->dyn_type != O_LIMIT_PARENT) 1437 NEXT_RULE(); 1438 1439 if (q->count != 0) 1440 NEXT_RULE(); 1441 1442 /* Parent rule without consumers */ 1443 1444 /* Unlink q from current list */ 1445 q_next = q->next; 1446 if (q == V_ipfw_dyn_v[i].head) 1447 V_ipfw_dyn_v[i].head = q_next; 1448 else 1449 q_prev->next = q_next; 1450 1451 q->next = NULL; 1452 1453 /* Add to expired list */ 1454 *exptailp = q; 1455 exptailp = &(*exptailp)->next; 1456 1457 DEB(print_dyn_rule(&q->id, q->dyn_type, 1458 "unlink parent entry", "left"); 1459 ) 1460 1461 expired++; 1462 1463 q = q_next; 1464 } 1465 IPFW_BUCK_UNLOCK(i); 1466 } 1467 } 1468 1469#undef NEXT_RULE 1470 1471 if (timer != 0) { 1472 /* 1473 * Check if we need to resize hash: 1474 * if current number of states exceeds number of buckes in hash, 1475 * grow hash size to the minimum power of 2 which is bigger than 1476 * current states count. Limit hash size by 64k. 1477 */ 1478 max_buckets = (V_dyn_buckets_max > 65536) ? 1479 65536 : V_dyn_buckets_max; 1480 1481 dyn_count = DYN_COUNT; 1482 1483 if ((dyn_count > V_curr_dyn_buckets * 2) && 1484 (dyn_count < max_buckets)) { 1485 new_buckets = V_curr_dyn_buckets; 1486 while (new_buckets < dyn_count) { 1487 new_buckets *= 2; 1488 1489 if (new_buckets >= max_buckets) 1490 break; 1491 } 1492 } 1493 1494 IPFW_UH_WUNLOCK(chain); 1495 } 1496 1497 /* Finally delete old states ad limits if any */ 1498 for (q = exp_head; q != NULL; q = q_next) { 1499 q_next = q->next; 1500 uma_zfree(V_ipfw_dyn_rule_zone, q); 1501 ipfw_dyn_count--; 1502 } 1503 1504 for (q = exp_lhead; q != NULL; q = q_next) { 1505 q_next = q->next; 1506 uma_zfree(V_ipfw_dyn_rule_zone, q); 1507 ipfw_dyn_count--; 1508 } 1509 1510 /* 1511 * The rest code MUST be called from timer routine only 1512 * without holding any locks 1513 */ 1514 if (timer == 0) 1515 return; 1516 1517 /* Send keepalive packets if any */ 1518 for (m = m0; m != NULL; m = mnext) { 1519 mnext = m->m_nextpkt; 1520 m->m_nextpkt = NULL; 1521 h = mtod(m, struct ip *); 1522 if (h->ip_v == 4) 1523 ip_output(m, NULL, NULL, 0, NULL, NULL); 1524#ifdef INET6 1525 else 1526 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 1527#endif 1528 } 1529 1530 /* Run table resize without holding any locks */ 1531 if (new_buckets != 0) 1532 resize_dynamic_table(chain, new_buckets); 1533} 1534 1535/* 1536 * Deletes all dynamic rules originated by given rule or all rules in 1537 * given set. Specify RESVD_SET to indicate set should not be used. 1538 * @chain - pointer to current ipfw rules chain 1539 * @rr - delete all states originated by rules in matched range. 1540 * 1541 * Function has to be called with IPFW_UH_WLOCK held. 1542 * Additionally, function assume that dynamic rule/set is 1543 * ALREADY deleted so no new states can be generated by 1544 * 'deleted' rules. 1545 */ 1546void 1547ipfw_expire_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt) 1548{ 1549 1550 check_dyn_rules(chain, rt, 0, 0); 1551} 1552 1553/* 1554 * Check if rule contains at least one dynamic opcode. 1555 * 1556 * Returns 1 if such opcode is found, 0 otherwise. 1557 */ 1558int 1559ipfw_is_dyn_rule(struct ip_fw *rule) 1560{ 1561 int cmdlen, l; 1562 ipfw_insn *cmd; 1563 1564 l = rule->cmd_len; 1565 cmd = rule->cmd; 1566 cmdlen = 0; 1567 for ( ; l > 0 ; l -= cmdlen, cmd += cmdlen) { 1568 cmdlen = F_LEN(cmd); 1569 1570 switch (cmd->opcode) { 1571 case O_LIMIT: 1572 case O_KEEP_STATE: 1573 case O_PROBE_STATE: 1574 case O_CHECK_STATE: 1575 return (1); 1576 } 1577 } 1578 1579 return (0); 1580} 1581 1582void 1583ipfw_dyn_init(struct ip_fw_chain *chain) 1584{ 1585 1586 V_ipfw_dyn_v = NULL; 1587 V_dyn_buckets_max = 256; /* must be power of 2 */ 1588 V_curr_dyn_buckets = 256; /* must be power of 2 */ 1589 1590 V_dyn_ack_lifetime = 300; 1591 V_dyn_syn_lifetime = 20; 1592 V_dyn_fin_lifetime = 1; 1593 V_dyn_rst_lifetime = 1; 1594 V_dyn_udp_lifetime = 10; 1595 V_dyn_short_lifetime = 5; 1596 1597 V_dyn_keepalive_interval = 20; 1598 V_dyn_keepalive_period = 5; 1599 V_dyn_keepalive = 1; /* do send keepalives */ 1600 V_dyn_keepalive_last = time_uptime; 1601 1602 V_dyn_max = 16384; /* max # of dynamic rules */ 1603 1604 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule", 1605 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL, 1606 UMA_ALIGN_PTR, 0); 1607 1608 /* Enforce limit on dynamic rules */ 1609 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1610 1611 callout_init(&V_ipfw_timeout, 1); 1612 1613 /* 1614 * This can potentially be done on first dynamic rule 1615 * being added to chain. 1616 */ 1617 resize_dynamic_table(chain, V_curr_dyn_buckets); 1618 IPFW_ADD_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes); 1619} 1620 1621void 1622ipfw_dyn_uninit(int pass) 1623{ 1624 int i; 1625 1626 if (pass == 0) { 1627 callout_drain(&V_ipfw_timeout); 1628 return; 1629 } 1630 IPFW_DEL_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes); 1631 1632 if (V_ipfw_dyn_v != NULL) { 1633 /* 1634 * Skip deleting all dynamic states - 1635 * uma_zdestroy() does this more efficiently; 1636 */ 1637 1638 /* Destroy all mutexes */ 1639 for (i = 0 ; i < V_curr_dyn_buckets ; i++) 1640 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]); 1641 free(V_ipfw_dyn_v, M_IPFW); 1642 V_ipfw_dyn_v = NULL; 1643 } 1644 1645 uma_zdestroy(V_ipfw_dyn_rule_zone); 1646} 1647 1648#ifdef SYSCTL_NODE 1649/* 1650 * Get/set maximum number of dynamic states in given VNET instance. 1651 */ 1652static int 1653sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS) 1654{ 1655 int error; 1656 unsigned int nstates; 1657 1658 nstates = V_dyn_max; 1659 1660 error = sysctl_handle_int(oidp, &nstates, 0, req); 1661 /* Read operation or some error */ 1662 if ((error != 0) || (req->newptr == NULL)) 1663 return (error); 1664 1665 V_dyn_max = nstates; 1666 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max); 1667 1668 return (0); 1669} 1670 1671/* 1672 * Get current number of dynamic states in given VNET instance. 1673 */ 1674static int 1675sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS) 1676{ 1677 int error; 1678 unsigned int nstates; 1679 1680 nstates = DYN_COUNT; 1681 1682 error = sysctl_handle_int(oidp, &nstates, 0, req); 1683 1684 return (error); 1685} 1686#endif 1687 1688/* 1689 * Returns size of dynamic states in legacy format 1690 */ 1691int 1692ipfw_dyn_len(void) 1693{ 1694 1695 return (V_ipfw_dyn_v == NULL) ? 0 : 1696 (DYN_COUNT * sizeof(ipfw_dyn_rule)); 1697} 1698 1699/* 1700 * Returns number of dynamic states. 1701 * Used by dump format v1 (current). 1702 */ 1703int 1704ipfw_dyn_get_count(void) 1705{ 1706 1707 return (V_ipfw_dyn_v == NULL) ? 0 : DYN_COUNT; 1708} 1709 1710static void 1711export_dyn_rule(ipfw_dyn_rule *src, ipfw_dyn_rule *dst) 1712{ 1713 uint16_t rulenum; 1714 1715 rulenum = (uint16_t)src->rule->rulenum; 1716 memcpy(dst, src, sizeof(*src)); 1717 memcpy(&dst->rule, &rulenum, sizeof(rulenum)); 1718 /* 1719 * store set number into high word of 1720 * dst->rule pointer. 1721 */ 1722 memcpy((char *)&dst->rule + sizeof(rulenum), &src->rule->set, 1723 sizeof(src->rule->set)); 1724 /* 1725 * store a non-null value in "next". 1726 * The userland code will interpret a 1727 * NULL here as a marker 1728 * for the last dynamic rule. 1729 */ 1730 memcpy(&dst->next, &dst, sizeof(dst)); 1731 dst->expire = TIME_LEQ(dst->expire, time_uptime) ? 0: 1732 dst->expire - time_uptime; 1733} 1734 1735/* 1736 * Fills int buffer given by @sd with dynamic states. 1737 * Used by dump format v1 (current). 1738 * 1739 * Returns 0 on success. 1740 */ 1741int 1742ipfw_dump_states(struct ip_fw_chain *chain, struct sockopt_data *sd) 1743{ 1744 ipfw_dyn_rule *p; 1745 ipfw_obj_dyntlv *dst, *last; 1746 ipfw_obj_ctlv *ctlv; 1747 int i; 1748 size_t sz; 1749 1750 if (V_ipfw_dyn_v == NULL) 1751 return (0); 1752 1753 IPFW_UH_RLOCK_ASSERT(chain); 1754 1755 ctlv = (ipfw_obj_ctlv *)ipfw_get_sopt_space(sd, sizeof(*ctlv)); 1756 if (ctlv == NULL) 1757 return (ENOMEM); 1758 sz = sizeof(ipfw_obj_dyntlv); 1759 ctlv->head.type = IPFW_TLV_DYNSTATE_LIST; 1760 ctlv->objsize = sz; 1761 last = NULL; 1762 1763 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1764 IPFW_BUCK_LOCK(i); 1765 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1766 dst = (ipfw_obj_dyntlv *)ipfw_get_sopt_space(sd, sz); 1767 if (dst == NULL) { 1768 IPFW_BUCK_UNLOCK(i); 1769 return (ENOMEM); 1770 } 1771 1772 export_dyn_rule(p, &dst->state); 1773 dst->head.length = sz; 1774 dst->head.type = IPFW_TLV_DYN_ENT; 1775 last = dst; 1776 } 1777 IPFW_BUCK_UNLOCK(i); 1778 } 1779 1780 if (last != NULL) /* mark last dynamic rule */ 1781 last->head.flags = IPFW_DF_LAST; 1782 1783 return (0); 1784} 1785 1786/* 1787 * Fill given buffer with dynamic states (legacy format). 1788 * IPFW_UH_RLOCK has to be held while calling. 1789 */ 1790void 1791ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep) 1792{ 1793 ipfw_dyn_rule *p, *last = NULL; 1794 char *bp; 1795 int i; 1796 1797 if (V_ipfw_dyn_v == NULL) 1798 return; 1799 bp = *pbp; 1800 1801 IPFW_UH_RLOCK_ASSERT(chain); 1802 1803 for (i = 0 ; i < V_curr_dyn_buckets; i++) { 1804 IPFW_BUCK_LOCK(i); 1805 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) { 1806 if (bp + sizeof *p <= ep) { 1807 ipfw_dyn_rule *dst = 1808 (ipfw_dyn_rule *)bp; 1809 1810 export_dyn_rule(p, dst); 1811 last = dst; 1812 bp += sizeof(ipfw_dyn_rule); 1813 } 1814 } 1815 IPFW_BUCK_UNLOCK(i); 1816 } 1817 1818 if (last != NULL) /* mark last dynamic rule */ 1819 bzero(&last->next, sizeof(last)); 1820 *pbp = bp; 1821} 1822/* end of file */ 1823