dummynet2/ip_fw_dynamic.c

   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: head/sys/netinet/ipfw/ip_fw_dynamic.c 200601 2009-12-16 10:48:40Z luigi $");
  28
  29 #define        DEB(x)
  30 #define        DDB(x) x
  31
  32 /*
  33  * Dynamic rule support for ipfw
  34  */
  35
  36 #if !defined(KLD_MODULE)
  37 #include "opt_ipfw.h"
  38 #include "opt_ipdivert.h"
  39 #include "opt_ipdn.h"
  40 #include "opt_inet.h"
  41 #ifndef INET
  42 #error IPFIREWALL requires INET.
  43 #endif /* INET */
  44 #endif
  45 #include "opt_inet6.h"
  46 #include "opt_ipsec.h"
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mbuf.h>
  52 #include <sys/kernel.h>
  53 #include <sys/lock.h>
  54 #include <sys/socket.h>
  55 #include <sys/sysctl.h>
  56 #include <sys/syslog.h>
  57 #include <net/ethernet.h> /* for ETHERTYPE_IP */
  58 #include <net/if.h>
  59 #include <net/vnet.h>
  60
  61 #include <netinet/in.h>
  62 #include <netinet/ip.h>
  63 #include <netinet/ip_var.h>     /* ip_defttl */
  64 #include <netinet/ip_fw.h>
  65 #include <netinet/ipfw/ip_fw_private.h>
  66 #include <netinet/tcp_var.h>
  67 #include <netinet/udp.h>
  68
  69 #include <netinet/ip6.h>        /* IN6_ARE_ADDR_EQUAL */
  70 #ifdef INET6
  71 #include <netinet6/in6_var.h>
  72 #include <netinet6/ip6_var.h>
  73 #endif
  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 stored in dyn_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. XXX we should make them survive.
 112  *
 113  * There are some limitations with dynamic rules -- we do not
 114  * obey the 'randomized match', and we do not do multiple
 115  * passes through the firewall. XXX check the latter!!!
 116  */
 117
 118 /*
 119  * Static variables followed by global ones
 120  */
 121 static VNET_DEFINE(ipfw_dyn_rule **, ipfw_dyn_v);
 122 static VNET_DEFINE(u_int32_t, dyn_buckets);
 123 static VNET_DEFINE(u_int32_t, curr_dyn_buckets);
 124 static VNET_DEFINE(struct callout, ipfw_timeout);
 125 #define V_ipfw_dyn_v                    VNET(ipfw_dyn_v)
 126 #define V_dyn_buckets                   VNET(dyn_buckets)
 127 #define V_curr_dyn_buckets              VNET(curr_dyn_buckets)
 128 #define V_ipfw_timeout                  VNET(ipfw_timeout)
 129
 130 static uma_zone_t ipfw_dyn_rule_zone;
 131 #ifndef __FreeBSD__
 132 DEFINE_SPINLOCK(ipfw_dyn_mtx);
 133 #else
 134 static struct mtx ipfw_dyn_mtx;         /* mutex guarding dynamic rules */
 135 #endif
 136
 137 #define IPFW_DYN_LOCK_INIT() \
 138         mtx_init(&ipfw_dyn_mtx, "IPFW dynamic rules", NULL, MTX_DEF)
 139 #define IPFW_DYN_LOCK_DESTROY() mtx_destroy(&ipfw_dyn_mtx)
 140 #define IPFW_DYN_LOCK()         mtx_lock(&ipfw_dyn_mtx)
 141 #define IPFW_DYN_UNLOCK()       mtx_unlock(&ipfw_dyn_mtx)
 142 #define IPFW_DYN_LOCK_ASSERT()  mtx_assert(&ipfw_dyn_mtx, MA_OWNED)
 143
 144 void
 145 ipfw_dyn_unlock(void)
 146 {
 147         IPFW_DYN_UNLOCK();
 148 }
 149
 150 /*
 151  * Timeouts for various events in handing dynamic rules.
 152  */
 153 static VNET_DEFINE(u_int32_t, dyn_ack_lifetime);
 154 static VNET_DEFINE(u_int32_t, dyn_syn_lifetime);
 155 static VNET_DEFINE(u_int32_t, dyn_fin_lifetime);
 156 static VNET_DEFINE(u_int32_t, dyn_rst_lifetime);
 157 static VNET_DEFINE(u_int32_t, dyn_udp_lifetime);
 158 static VNET_DEFINE(u_int32_t, dyn_short_lifetime);
 159
 160 #define V_dyn_ack_lifetime              VNET(dyn_ack_lifetime)
 161 #define V_dyn_syn_lifetime              VNET(dyn_syn_lifetime)
 162 #define V_dyn_fin_lifetime              VNET(dyn_fin_lifetime)
 163 #define V_dyn_rst_lifetime              VNET(dyn_rst_lifetime)
 164 #define V_dyn_udp_lifetime              VNET(dyn_udp_lifetime)
 165 #define V_dyn_short_lifetime            VNET(dyn_short_lifetime)
 166
 167 /*
 168  * Keepalives are sent if dyn_keepalive is set. They are sent every
 169  * dyn_keepalive_period seconds, in the last dyn_keepalive_interval
 170  * seconds of lifetime of a rule.
 171  * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower
 172  * than dyn_keepalive_period.
 173  */
 174
 175 static VNET_DEFINE(u_int32_t, dyn_keepalive_interval);
 176 static VNET_DEFINE(u_int32_t, dyn_keepalive_period);
 177 static VNET_DEFINE(u_int32_t, dyn_keepalive);
 178
 179 #define V_dyn_keepalive_interval        VNET(dyn_keepalive_interval)
 180 #define V_dyn_keepalive_period          VNET(dyn_keepalive_period)
 181 #define V_dyn_keepalive                 VNET(dyn_keepalive)
 182
 183 static VNET_DEFINE(u_int32_t, dyn_count);       /* # of dynamic rules */
 184 static VNET_DEFINE(u_int32_t, dyn_max);         /* max # of dynamic rules */
 185
 186 #define V_dyn_count                     VNET(dyn_count)
 187 #define V_dyn_max                       VNET(dyn_max)
 188
 189 #ifdef SYSCTL_NODE
 190
 191 SYSBEGIN(f2)
 192
 193 SYSCTL_DECL(_net_inet_ip_fw);
 194 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets,
 195     CTLFLAG_RW, &VNET_NAME(dyn_buckets), 0,
 196     "Number of dyn. buckets");
 197 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets,
 198     CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0,
 199     "Current Number of dyn. buckets");
 200 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_count,
 201     CTLFLAG_RD, &VNET_NAME(dyn_count), 0,
 202     "Number of dyn. rules");
 203 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_max,
 204     CTLFLAG_RW, &VNET_NAME(dyn_max), 0,
 205     "Max number of dyn. rules");
 206 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime,
 207     CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0,
 208     "Lifetime of dyn. rules for acks");
 209 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime,
 210     CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0,
 211     "Lifetime of dyn. rules for syn");
 212 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime,
 213     CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0,
 214     "Lifetime of dyn. rules for fin");
 215 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime,
 216     CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0,
 217     "Lifetime of dyn. rules for rst");
 218 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime,
 219     CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0,
 220     "Lifetime of dyn. rules for UDP");
 221 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime,
 222     CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0,
 223     "Lifetime of dyn. rules for other situations");
 224 SYSCTL_VNET_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive,
 225     CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0,
 226     "Enable keepalives for dyn. rules");
 227
 228 SYSEND
 229
 230 #endif /* SYSCTL_NODE */
 231
 232
 233 static __inline int
 234 hash_packet6(struct ipfw_flow_id *id)
 235 {
 236         u_int32_t i;
 237         i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^
 238             (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^
 239             (id->src_ip6.__u6_addr.__u6_addr32[2]) ^
 240             (id->src_ip6.__u6_addr.__u6_addr32[3]) ^
 241             (id->dst_port) ^ (id->src_port);
 242         return i;
 243 }
 244
 245 /*
 246  * IMPORTANT: the hash function for dynamic rules must be commutative
 247  * in source and destination (ip,port), because rules are bidirectional
 248  * and we want to find both in the same bucket.
 249  */
 250 static __inline int
 251 hash_packet(struct ipfw_flow_id *id)
 252 {
 253         u_int32_t i;
 254
 255 #ifdef INET6
 256         if (IS_IP6_FLOW_ID(id))
 257                 i = hash_packet6(id);
 258         else
 259 #endif /* INET6 */
 260         i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
 261         i &= (V_curr_dyn_buckets - 1);
 262         return i;
 263 }
 264
 265 static __inline void
 266 unlink_dyn_rule_print(struct ipfw_flow_id *id)
 267 {
 268         struct in_addr da;
 269 #ifdef INET6
 270         char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
 271 #else
 272         char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN];
 273 #endif
 274
 275 #ifdef INET6
 276         if (IS_IP6_FLOW_ID(id)) {
 277                 ip6_sprintf(src, &id->src_ip6);
 278                 ip6_sprintf(dst, &id->dst_ip6);
 279         } else
 280 #endif
 281         {
 282                 da.s_addr = htonl(id->src_ip);
 283                 inet_ntoa_r(da, src);
 284                 da.s_addr = htonl(id->dst_ip);
 285                 inet_ntoa_r(da, dst);
 286         }
 287         printf("ipfw: unlink entry %s %d -> %s %d, %d left\n",
 288             src, id->src_port, dst, id->dst_port, V_dyn_count - 1);
 289 }
 290
 291 /**
 292  * unlink a dynamic rule from a chain. prev is a pointer to
 293  * the previous one, q is a pointer to the rule to delete,
 294  * head is a pointer to the head of the queue.
 295  * Modifies q and potentially also head.
 296  */
 297 #define UNLINK_DYN_RULE(prev, head, q) {                                \
 298         ipfw_dyn_rule *old_q = q;                                       \
 299                                                                         \
 300         /* remove a refcount to the parent */                           \
 301         if (q->dyn_type == O_LIMIT)                                     \
 302                 q->parent->count--;                                     \
 303         DEB(unlink_dyn_rule_print(&q->id);)                             \
 304         if (prev != NULL)                                               \
 305                 prev->next = q = q->next;                               \
 306         else                                                            \
 307                 head = q = q->next;                                     \
 308         V_dyn_count--;                                                  \
 309         uma_zfree(ipfw_dyn_rule_zone, old_q); }
 310
 311 #define TIME_LEQ(a,b)       ((int)((a)-(b)) <= 0)
 312
 313 /**
 314  * Remove dynamic rules pointing to "rule", or all of them if rule == NULL.
 315  *
 316  * If keep_me == NULL, rules are deleted even if not expired,
 317  * otherwise only expired rules are removed.
 318  *
 319  * The value of the second parameter is also used to point to identify
 320  * a rule we absolutely do not want to remove (e.g. because we are
 321  * holding a reference to it -- this is the case with O_LIMIT_PARENT
 322  * rules). The pointer is only used for comparison, so any non-null
 323  * value will do.
 324  */
 325 static void
 326 remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me)
 327 {
 328         static u_int32_t last_remove = 0;
 329
 330 #define FORCE (keep_me == NULL)
 331
 332         ipfw_dyn_rule *prev, *q;
 333         int i, pass = 0, max_pass = 0;
 334
 335         IPFW_DYN_LOCK_ASSERT();
 336
 337         if (V_ipfw_dyn_v == NULL || V_dyn_count == 0)
 338                 return;
 339         /* do not expire more than once per second, it is useless */
 340         if (!FORCE && last_remove == time_uptime)
 341                 return;
 342         last_remove = time_uptime;
 343
 344         /*
 345          * because O_LIMIT refer to parent rules, during the first pass only
 346          * remove child and mark any pending LIMIT_PARENT, and remove
 347          * them in a second pass.
 348          */
 349 next_pass:
 350         for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
 351                 for (prev=NULL, q = V_ipfw_dyn_v[i] ; q ; ) {
 352                         /*
 353                          * Logic can become complex here, so we split tests.
 354                          */
 355                         if (q == keep_me)
 356                                 goto next;
 357                         if (rule != NULL && rule != q->rule)
 358                                 goto next; /* not the one we are looking for */
 359                         if (q->dyn_type == O_LIMIT_PARENT) {
 360                                 /*
 361                                  * handle parent in the second pass,
 362                                  * record we need one.
 363                                  */
 364                                 max_pass = 1;
 365                                 if (pass == 0)
 366                                         goto next;
 367                                 if (FORCE && q->count != 0 ) {
 368                                         /* XXX should not happen! */
 369                                         printf("ipfw: OUCH! cannot remove rule,"
 370                                              " count %d\n", q->count);
 371                                 }
 372                         } else {
 373                                 if (!FORCE &&
 374                                     !TIME_LEQ( q->expire, time_uptime ))
 375                                         goto next;
 376                         }
 377              if (q->dyn_type != O_LIMIT_PARENT || !q->count) {
 378                      UNLINK_DYN_RULE(prev, V_ipfw_dyn_v[i], q);
 379                      continue;
 380              }
 381 next:
 382                         prev=q;
 383                         q=q->next;
 384                 }
 385         }
 386         if (pass++ < max_pass)
 387                 goto next_pass;
 388 }
 389
 390 void
 391 ipfw_remove_dyn_children(struct ip_fw *rule)
 392 {
 393         IPFW_DYN_LOCK();
 394         remove_dyn_rule(rule, NULL /* force removal */);
 395         IPFW_DYN_UNLOCK();
 396 }
 397
 398 /**
 399  * lookup a dynamic rule, locked version
 400  */
 401 static ipfw_dyn_rule *
 402 lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int *match_direction,
 403     struct tcphdr *tcp)
 404 {
 405         /*
 406          * stateful ipfw extensions.
 407          * Lookup into dynamic session queue
 408          */
 409 #define MATCH_REVERSE   0
 410 #define MATCH_FORWARD   1
 411 #define MATCH_NONE      2
 412 #define MATCH_UNKNOWN   3
 413         int i, dir = MATCH_NONE;
 414         ipfw_dyn_rule *prev, *q=NULL;
 415
 416         IPFW_DYN_LOCK_ASSERT();
 417
 418         if (V_ipfw_dyn_v == NULL)
 419                 goto done;      /* not found */
 420         i = hash_packet( pkt );
 421         for (prev=NULL, q = V_ipfw_dyn_v[i] ; q != NULL ; ) {
 422                 if (q->dyn_type == O_LIMIT_PARENT && q->count)
 423                         goto next;
 424                 if (TIME_LEQ( q->expire, time_uptime)) { /* expire entry */
 425                         UNLINK_DYN_RULE(prev, V_ipfw_dyn_v[i], q);
 426                         continue;
 427                 }
 428                 if (pkt->proto == q->id.proto &&
 429                     q->dyn_type != O_LIMIT_PARENT) {
 430                         if (IS_IP6_FLOW_ID(pkt)) {
 431                             if (IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6),
 432                                 &(q->id.src_ip6)) &&
 433                             IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6),
 434                                 &(q->id.dst_ip6)) &&
 435                             pkt->src_port == q->id.src_port &&
 436                             pkt->dst_port == q->id.dst_port ) {
 437                                 dir = MATCH_FORWARD;
 438                                 break;
 439                             }
 440                             if (IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6),
 441                                     &(q->id.dst_ip6)) &&
 442                                 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6),
 443                                     &(q->id.src_ip6)) &&
 444                                 pkt->src_port == q->id.dst_port &&
 445                                 pkt->dst_port == q->id.src_port ) {
 446                                     dir = MATCH_REVERSE;
 447                                     break;
 448                             }
 449                         } else {
 450                             if (pkt->src_ip == q->id.src_ip &&
 451                                 pkt->dst_ip == q->id.dst_ip &&
 452                                 pkt->src_port == q->id.src_port &&
 453                                 pkt->dst_port == q->id.dst_port ) {
 454                                     dir = MATCH_FORWARD;
 455                                     break;
 456                             }
 457                             if (pkt->src_ip == q->id.dst_ip &&
 458                                 pkt->dst_ip == q->id.src_ip &&
 459                                 pkt->src_port == q->id.dst_port &&
 460                                 pkt->dst_port == q->id.src_port ) {
 461                                     dir = MATCH_REVERSE;
 462                                     break;
 463                             }
 464                         }
 465                 }
 466 next:
 467                 prev = q;
 468                 q = q->next;
 469         }
 470         if (q == NULL)
 471                 goto done; /* q = NULL, not found */
 472
 473         if ( prev != NULL) { /* found and not in front */
 474                 prev->next = q->next;
 475                 q->next = V_ipfw_dyn_v[i];
 476                 V_ipfw_dyn_v[i] = q;
 477         }
 478         if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */
 479                 u_char flags = pkt->_flags & (TH_FIN|TH_SYN|TH_RST);
 480
 481 #define BOTH_SYN        (TH_SYN | (TH_SYN << 8))
 482 #define BOTH_FIN        (TH_FIN | (TH_FIN << 8))
 483                 q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8);
 484                 switch (q->state) {
 485                 case TH_SYN:                            /* opening */
 486                         q->expire = time_uptime + V_dyn_syn_lifetime;
 487                         break;
 488
 489                 case BOTH_SYN:                  /* move to established */
 490                 case BOTH_SYN | TH_FIN :        /* one side tries to close */
 491                 case BOTH_SYN | (TH_FIN << 8) :
 492                         if (tcp) {
 493 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
 494                             u_int32_t ack = ntohl(tcp->th_ack);
 495                             if (dir == MATCH_FORWARD) {
 496                                 if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd))
 497                                     q->ack_fwd = ack;
 498                                 else { /* ignore out-of-sequence */
 499                                     break;
 500                                 }
 501                             } else {
 502                                 if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev))
 503                                     q->ack_rev = ack;
 504                                 else { /* ignore out-of-sequence */
 505                                     break;
 506                                 }
 507                             }
 508                         }
 509                         q->expire = time_uptime + V_dyn_ack_lifetime;
 510                         break;
 511
 512                 case BOTH_SYN | BOTH_FIN:       /* both sides closed */
 513                         if (V_dyn_fin_lifetime >= V_dyn_keepalive_period)
 514                                 V_dyn_fin_lifetime = V_dyn_keepalive_period - 1;
 515                         q->expire = time_uptime + V_dyn_fin_lifetime;
 516                         break;
 517
 518                 default:
 519 #if 0
 520                         /*
 521                          * reset or some invalid combination, but can also
 522                          * occur if we use keep-state the wrong way.
 523                          */
 524                         if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
 525                                 printf("invalid state: 0x%x\n", q->state);
 526 #endif
 527                         if (V_dyn_rst_lifetime >= V_dyn_keepalive_period)
 528                                 V_dyn_rst_lifetime = V_dyn_keepalive_period - 1;
 529                         q->expire = time_uptime + V_dyn_rst_lifetime;
 530                         break;
 531                 }
 532         } else if (pkt->proto == IPPROTO_UDP) {
 533                 q->expire = time_uptime + V_dyn_udp_lifetime;
 534         } else {
 535                 /* other protocols */
 536                 q->expire = time_uptime + V_dyn_short_lifetime;
 537         }
 538 done:
 539         if (match_direction)
 540                 *match_direction = dir;
 541         return q;
 542 }
 543
 544 ipfw_dyn_rule *
 545 ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction,
 546     struct tcphdr *tcp)
 547 {
 548         ipfw_dyn_rule *q;
 549
 550         IPFW_DYN_LOCK();
 551         q = lookup_dyn_rule_locked(pkt, match_direction, tcp);
 552         if (q == NULL)
 553                 IPFW_DYN_UNLOCK();
 554         /* NB: return table locked when q is not NULL */
 555         return q;
 556 }
 557
 558 static void
 559 realloc_dynamic_table(void)
 560 {
 561         IPFW_DYN_LOCK_ASSERT();
 562
 563         /*
 564          * Try reallocation, make sure we have a power of 2 and do
 565          * not allow more than 64k entries. In case of overflow,
 566          * default to 1024.
 567          */
 568
 569         if (V_dyn_buckets > 65536)
 570                 V_dyn_buckets = 1024;
 571         if ((V_dyn_buckets & (V_dyn_buckets-1)) != 0) { /* not a power of 2 */
 572                 V_dyn_buckets = V_curr_dyn_buckets; /* reset */
 573                 return;
 574         }
 575         V_curr_dyn_buckets = V_dyn_buckets;
 576         if (V_ipfw_dyn_v != NULL)
 577                 free(V_ipfw_dyn_v, M_IPFW);
 578         for (;;) {
 579                 V_ipfw_dyn_v = malloc(V_curr_dyn_buckets * sizeof(ipfw_dyn_rule *),
 580                        M_IPFW, M_NOWAIT | M_ZERO);
 581                 if (V_ipfw_dyn_v != NULL || V_curr_dyn_buckets <= 2)
 582                         break;
 583                 V_curr_dyn_buckets /= 2;
 584         }
 585 }
 586
 587 /**
 588  * Install state of type 'type' for a dynamic session.
 589  * The hash table contains two type of rules:
 590  * - regular rules (O_KEEP_STATE)
 591  * - rules for sessions with limited number of sess per user
 592  *   (O_LIMIT). When they are created, the parent is
 593  *   increased by 1, and decreased on delete. In this case,
 594  *   the third parameter is the parent rule and not the chain.
 595  * - "parent" rules for the above (O_LIMIT_PARENT).
 596  */
 597 static ipfw_dyn_rule *
 598 add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule)
 599 {
 600         ipfw_dyn_rule *r;
 601         int i;
 602
 603         IPFW_DYN_LOCK_ASSERT();
 604
 605         if (V_ipfw_dyn_v == NULL ||
 606             (V_dyn_count == 0 && V_dyn_buckets != V_curr_dyn_buckets)) {
 607                 realloc_dynamic_table();
 608                 if (V_ipfw_dyn_v == NULL)
 609                         return NULL; /* failed ! */
 610         }
 611         i = hash_packet(id);
 612
 613         r = uma_zalloc(ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO);
 614         if (r == NULL) {
 615                 printf ("ipfw: sorry cannot allocate state\n");
 616                 return NULL;
 617         }
 618
 619         /* increase refcount on parent, and set pointer */
 620         if (dyn_type == O_LIMIT) {
 621                 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule;
 622                 if ( parent->dyn_type != O_LIMIT_PARENT)
 623                         panic("invalid parent");
 624                 parent->count++;
 625                 r->parent = parent;
 626                 rule = parent->rule;
 627         }
 628
 629         r->id = *id;
 630         r->expire = time_uptime + V_dyn_syn_lifetime;
 631         r->rule = rule;
 632         r->dyn_type = dyn_type;
 633         r->pcnt = r->bcnt = 0;
 634         r->count = 0;
 635
 636         r->bucket = i;
 637         r->next = V_ipfw_dyn_v[i];
 638         V_ipfw_dyn_v[i] = r;
 639         V_dyn_count++;
 640         DEB({
 641                 struct in_addr da;
 642 #ifdef INET6
 643                 char src[INET6_ADDRSTRLEN];
 644                 char dst[INET6_ADDRSTRLEN];
 645 #else
 646                 char src[INET_ADDRSTRLEN];
 647                 char dst[INET_ADDRSTRLEN];
 648 #endif
 649
 650 #ifdef INET6
 651                 if (IS_IP6_FLOW_ID(&(r->id))) {
 652                         ip6_sprintf(src, &r->id.src_ip6);
 653                         ip6_sprintf(dst, &r->id.dst_ip6);
 654                 } else
 655 #endif
 656                 {
 657                         da.s_addr = htonl(r->id.src_ip);
 658                         inet_ntoa_r(da, src);
 659                         da.s_addr = htonl(r->id.dst_ip);
 660                         inet_ntoa_r(da, dst);
 661                 }
 662                 printf("ipfw: add dyn entry ty %d %s %d -> %s %d, total %d\n",
 663                     dyn_type, src, r->id.src_port, dst, r->id.dst_port,
 664                     V_dyn_count);
 665         })
 666         return r;
 667 }
 668
 669 /**
 670  * lookup dynamic parent rule using pkt and rule as search keys.
 671  * If the lookup fails, then install one.
 672  */
 673 static ipfw_dyn_rule *
 674 lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule)
 675 {
 676         ipfw_dyn_rule *q;
 677         int i;
 678
 679         IPFW_DYN_LOCK_ASSERT();
 680
 681         if (V_ipfw_dyn_v) {
 682                 int is_v6 = IS_IP6_FLOW_ID(pkt);
 683                 i = hash_packet( pkt );
 684                 for (q = V_ipfw_dyn_v[i] ; q != NULL ; q=q->next)
 685                         if (q->dyn_type == O_LIMIT_PARENT &&
 686                             rule== q->rule &&
 687                             pkt->proto == q->id.proto &&
 688                             pkt->src_port == q->id.src_port &&
 689                             pkt->dst_port == q->id.dst_port &&
 690                             (
 691                                 (is_v6 &&
 692                                  IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6),
 693                                         &(q->id.src_ip6)) &&
 694                                  IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6),
 695                                         &(q->id.dst_ip6))) ||
 696                                 (!is_v6 &&
 697                                  pkt->src_ip == q->id.src_ip &&
 698                                  pkt->dst_ip == q->id.dst_ip)
 699                             )
 700                         ) {
 701                                 q->expire = time_uptime + V_dyn_short_lifetime;
 702                                 DEB(printf("ipfw: lookup_dyn_parent found 0x%p\n",q);)
 703                                 return q;
 704                         }
 705         }
 706         return add_dyn_rule(pkt, O_LIMIT_PARENT, rule);
 707 }
 708
 709 /**
 710  * Install dynamic state for rule type cmd->o.opcode
 711  *
 712  * Returns 1 (failure) if state is not installed because of errors or because
 713  * session limitations are enforced.
 714  */
 715 int
 716 ipfw_install_state(struct ip_fw *rule, ipfw_insn_limit *cmd,
 717     struct ip_fw_args *args, uint32_t tablearg)
 718 {
 719         static int last_log;
 720         ipfw_dyn_rule *q;
 721         struct in_addr da;
 722 #ifdef INET6
 723         char src[INET6_ADDRSTRLEN + 2], dst[INET6_ADDRSTRLEN + 2];
 724 #else
 725         char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN];
 726 #endif
 727
 728         src[0] = '\0';
 729         dst[0] = '\0';
 730
 731         IPFW_DYN_LOCK();
 732
 733         DEB(
 734 #ifdef INET6
 735         if (IS_IP6_FLOW_ID(&(args->f_id))) {
 736                 ip6_sprintf(src, &args->f_id.src_ip6);
 737                 ip6_sprintf(dst, &args->f_id.dst_ip6);
 738         } else
 739 #endif
 740         {
 741                 da.s_addr = htonl(args->f_id.src_ip);
 742                 inet_ntoa_r(da, src);
 743                 da.s_addr = htonl(args->f_id.dst_ip);
 744                 inet_ntoa_r(da, dst);
 745         }
 746         printf("ipfw: %s: type %d %s %u -> %s %u\n",
 747             __func__, cmd->o.opcode, src, args->f_id.src_port,
 748             dst, args->f_id.dst_port);
 749         src[0] = '\0';
 750         dst[0] = '\0';
 751         )
 752
 753         q = lookup_dyn_rule_locked(&args->f_id, NULL, NULL);
 754
 755         if (q != NULL) {        /* should never occur */
 756                 if (last_log != time_uptime) {
 757                         last_log = time_uptime;
 758                         printf("ipfw: %s: entry already present, done\n",
 759                             __func__);
 760                 }
 761                 IPFW_DYN_UNLOCK();
 762                 return (0);
 763         }
 764
 765         if (V_dyn_count >= V_dyn_max)
 766                 /* Run out of slots, try to remove any expired rule. */
 767                 remove_dyn_rule(NULL, (ipfw_dyn_rule *)1);
 768
 769         if (V_dyn_count >= V_dyn_max) {
 770                 if (last_log != time_uptime) {
 771                         last_log = time_uptime;
 772                         printf("ipfw: %s: Too many dynamic rules\n", __func__);
 773                 }
 774                 IPFW_DYN_UNLOCK();
 775                 return (1);     /* cannot install, notify caller */
 776         }
 777
 778         switch (cmd->o.opcode) {
 779         case O_KEEP_STATE:      /* bidir rule */
 780                 add_dyn_rule(&args->f_id, O_KEEP_STATE, rule);
 781                 break;
 782
 783         case O_LIMIT: {         /* limit number of sessions */
 784                 struct ipfw_flow_id id;
 785                 ipfw_dyn_rule *parent;
 786                 uint32_t conn_limit;
 787                 uint16_t limit_mask = cmd->limit_mask;
 788
 789                 conn_limit = (cmd->conn_limit == IP_FW_TABLEARG) ?
 790                     tablearg : cmd->conn_limit;
 791
 792                 DEB(
 793                 if (cmd->conn_limit == IP_FW_TABLEARG)
 794                         printf("ipfw: %s: O_LIMIT rule, conn_limit: %u "
 795                             "(tablearg)\n", __func__, conn_limit);
 796                 else
 797                         printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n",
 798                             __func__, conn_limit);
 799                 )
 800
 801                 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0;
 802                 id.proto = args->f_id.proto;
 803                 id.addr_type = args->f_id.addr_type;
 804                 id.fib = M_GETFIB(args->m);
 805
 806                 if (IS_IP6_FLOW_ID (&(args->f_id))) {
 807                         if (limit_mask & DYN_SRC_ADDR)
 808                                 id.src_ip6 = args->f_id.src_ip6;
 809                         if (limit_mask & DYN_DST_ADDR)
 810                                 id.dst_ip6 = args->f_id.dst_ip6;
 811                 } else {
 812                         if (limit_mask & DYN_SRC_ADDR)
 813                                 id.src_ip = args->f_id.src_ip;
 814                         if (limit_mask & DYN_DST_ADDR)
 815                                 id.dst_ip = args->f_id.dst_ip;
 816                 }
 817                 if (limit_mask & DYN_SRC_PORT)
 818                         id.src_port = args->f_id.src_port;
 819                 if (limit_mask & DYN_DST_PORT)
 820                         id.dst_port = args->f_id.dst_port;
 821                 if ((parent = lookup_dyn_parent(&id, rule)) == NULL) {
 822                         printf("ipfw: %s: add parent failed\n", __func__);
 823                         IPFW_DYN_UNLOCK();
 824                         return (1);
 825                 }
 826
 827                 if (parent->count >= conn_limit) {
 828                         /* See if we can remove some expired rule. */
 829                         remove_dyn_rule(rule, parent);
 830                         if (parent->count >= conn_limit) {
 831                                 if (V_fw_verbose && last_log != time_uptime) {
 832                                         last_log = time_uptime;
 833 #ifdef INET6
 834                                         /*
 835                                          * XXX IPv6 flows are not
 836                                          * supported yet.
 837                                          */
 838                                         if (IS_IP6_FLOW_ID(&(args->f_id))) {
 839                                                 char ip6buf[INET6_ADDRSTRLEN];
 840                                                 snprintf(src, sizeof(src),
 841                                                     "[%s]", ip6_sprintf(ip6buf,
 842                                                         &args->f_id.src_ip6));
 843                                                 snprintf(dst, sizeof(dst),
 844                                                     "[%s]", ip6_sprintf(ip6buf,
 845                                                         &args->f_id.dst_ip6));
 846                                         } else
 847 #endif
 848                                         {
 849                                                 da.s_addr =
 850                                                     htonl(args->f_id.src_ip);
 851                                                 inet_ntoa_r(da, src);
 852                                                 da.s_addr =
 853                                                     htonl(args->f_id.dst_ip);
 854                                                 inet_ntoa_r(da, dst);
 855                                         }
 856                                         log(LOG_SECURITY | LOG_DEBUG,
 857                                             "ipfw: %d %s %s:%u -> %s:%u, %s\n",
 858                                             parent->rule->rulenum,
 859                                             "drop session",
 860                                             src, (args->f_id.src_port),
 861                                             dst, (args->f_id.dst_port),
 862                                             "too many entries");
 863                                 }
 864                                 IPFW_DYN_UNLOCK();
 865                                 return (1);
 866                         }
 867                 }
 868                 add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent);
 869                 break;
 870         }
 871         default:
 872                 printf("ipfw: %s: unknown dynamic rule type %u\n",
 873                     __func__, cmd->o.opcode);
 874                 IPFW_DYN_UNLOCK();
 875                 return (1);
 876         }
 877
 878         /* XXX just set lifetime */
 879         lookup_dyn_rule_locked(&args->f_id, NULL, NULL);
 880
 881         IPFW_DYN_UNLOCK();
 882         return (0);
 883 }
 884
 885 /*
 886  * Generate a TCP packet, containing either a RST or a keepalive.
 887  * When flags & TH_RST, we are sending a RST packet, because of a
 888  * "reset" action matched the packet.
 889  * Otherwise we are sending a keepalive, and flags & TH_
 890  * The 'replyto' mbuf is the mbuf being replied to, if any, and is required
 891  * so that MAC can label the reply appropriately.
 892  */
 893 struct mbuf *
 894 ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq,
 895     u_int32_t ack, int flags)
 896 {
 897         struct mbuf *m = NULL;          /* stupid compiler */
 898         int len, dir;
 899         struct ip *h = NULL;            /* stupid compiler */
 900 #ifdef INET6
 901         struct ip6_hdr *h6 = NULL;
 902 #endif
 903         struct tcphdr *th = NULL;
 904
 905         MGETHDR(m, M_DONTWAIT, MT_DATA);
 906         if (m == NULL)
 907                 return (NULL);
 908
 909         M_SETFIB(m, id->fib);
 910 #ifdef MAC
 911         if (replyto != NULL)
 912                 mac_netinet_firewall_reply(replyto, m);
 913         else
 914                 mac_netinet_firewall_send(m);
 915 #else
 916         (void)replyto;          /* don't warn about unused arg */
 917 #endif
 918
 919         switch (id->addr_type) {
 920         case 4:
 921                 len = sizeof(struct ip) + sizeof(struct tcphdr);
 922                 break;
 923 #ifdef INET6
 924         case 6:
 925                 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
 926                 break;
 927 #endif
 928         default:
 929                 /* XXX: log me?!? */
 930                 FREE_PKT(m);
 931                 return (NULL);
 932         }
 933         dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN);
 934
 935         m->m_data += max_linkhdr;
 936         m->m_flags |= M_SKIP_FIREWALL;
 937         m->m_pkthdr.len = m->m_len = len;
 938         m->m_pkthdr.rcvif = NULL;
 939         bzero(m->m_data, len);
 940
 941         switch (id->addr_type) {
 942         case 4:
 943                 h = mtod(m, struct ip *);
 944
 945                 /* prepare for checksum */
 946                 h->ip_p = IPPROTO_TCP;
 947                 h->ip_len = htons(sizeof(struct tcphdr));
 948                 if (dir) {
 949                         h->ip_src.s_addr = htonl(id->src_ip);
 950                         h->ip_dst.s_addr = htonl(id->dst_ip);
 951                 } else {
 952                         h->ip_src.s_addr = htonl(id->dst_ip);
 953                         h->ip_dst.s_addr = htonl(id->src_ip);
 954                 }
 955
 956                 th = (struct tcphdr *)(h + 1);
 957                 break;
 958 #ifdef INET6
 959         case 6:
 960                 h6 = mtod(m, struct ip6_hdr *);
 961
 962                 /* prepare for checksum */
 963                 h6->ip6_nxt = IPPROTO_TCP;
 964                 h6->ip6_plen = htons(sizeof(struct tcphdr));
 965                 if (dir) {
 966                         h6->ip6_src = id->src_ip6;
 967                         h6->ip6_dst = id->dst_ip6;
 968                 } else {
 969                         h6->ip6_src = id->dst_ip6;
 970                         h6->ip6_dst = id->src_ip6;
 971                 }
 972
 973                 th = (struct tcphdr *)(h6 + 1);
 974                 break;
 975 #endif
 976         }
 977
 978         if (dir) {
 979                 th->th_sport = htons(id->src_port);
 980                 th->th_dport = htons(id->dst_port);
 981         } else {
 982                 th->th_sport = htons(id->dst_port);
 983                 th->th_dport = htons(id->src_port);
 984         }
 985         th->th_off = sizeof(struct tcphdr) >> 2;
 986
 987         if (flags & TH_RST) {
 988                 if (flags & TH_ACK) {
 989                         th->th_seq = htonl(ack);
 990                         th->th_flags = TH_RST;
 991                 } else {
 992                         if (flags & TH_SYN)
 993                                 seq++;
 994                         th->th_ack = htonl(seq);
 995                         th->th_flags = TH_RST | TH_ACK;
 996                 }
 997         } else {
 998                 /*
 999                  * Keepalive - use caller provided sequence numbers
1000                  */
1001                 th->th_seq = htonl(seq);
1002                 th->th_ack = htonl(ack);
1003                 th->th_flags = TH_ACK;
1004         }
1005
1006         switch (id->addr_type) {
1007         case 4:
1008                 th->th_sum = in_cksum(m, len);
1009
1010                 /* finish the ip header */
1011                 h->ip_v = 4;
1012                 h->ip_hl = sizeof(*h) >> 2;
1013                 h->ip_tos = IPTOS_LOWDELAY;
1014                 h->ip_off = 0;
1015                 /* ip_len must be in host format for ip_output */
1016                 h->ip_len = len;
1017                 h->ip_ttl = V_ip_defttl;
1018                 h->ip_sum = 0;
1019                 break;
1020 #ifdef INET6
1021         case 6:
1022                 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6),
1023                     sizeof(struct tcphdr));
1024
1025                 /* finish the ip6 header */
1026                 h6->ip6_vfc |= IPV6_VERSION;
1027                 h6->ip6_hlim = IPV6_DEFHLIM;
1028                 break;
1029 #endif
1030         }
1031
1032         return (m);
1033 }
1034
1035 /*
1036  * This procedure is only used to handle keepalives. It is invoked
1037  * every dyn_keepalive_period
1038  */
1039  /* dummynet() and ipfw_tick() can't be static in windows */
1040 void
1041 ipfw_tick(void * vnetx)
1042 {
1043         struct mbuf *m0, *m, *mnext, **mtailp;
1044 #ifdef INET6
1045         struct mbuf *m6, **m6_tailp;
1046 #endif
1047         int i;
1048         ipfw_dyn_rule *q;
1049 #ifdef VIMAGE
1050         struct vnet *vp = vnetx;
1051 #endif
1052
1053         CURVNET_SET(vp);
1054         if (V_dyn_keepalive == 0 || V_ipfw_dyn_v == NULL || V_dyn_count == 0)
1055                 goto done;
1056
1057         /*
1058          * We make a chain of packets to go out here -- not deferring
1059          * until after we drop the IPFW dynamic rule lock would result
1060          * in a lock order reversal with the normal packet input -> ipfw
1061          * call stack.
1062          */
1063         m0 = NULL;
1064         mtailp = &m0;
1065 #ifdef INET6
1066         m6 = NULL;
1067         m6_tailp = &m6;
1068 #endif
1069         IPFW_DYN_LOCK();
1070         for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
1071                 for (q = V_ipfw_dyn_v[i] ; q ; q = q->next ) {
1072                         if (q->dyn_type == O_LIMIT_PARENT)
1073                                 continue;
1074                         if (q->id.proto != IPPROTO_TCP)
1075                                 continue;
1076                         if ( (q->state & BOTH_SYN) != BOTH_SYN)
1077                                 continue;
1078                         if (TIME_LEQ(time_uptime + V_dyn_keepalive_interval,
1079                             q->expire))
1080                                 continue;       /* too early */
1081                         if (TIME_LEQ(q->expire, time_uptime))
1082                                 continue;       /* too late, rule expired */
1083
1084                         m = ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1,
1085                                 q->ack_fwd, TH_SYN);
1086                         mnext = ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1,
1087                                 q->ack_rev, 0);
1088
1089                         switch (q->id.addr_type) {
1090                         case 4:
1091                                 if (m != NULL) {
1092                                         *mtailp = m;
1093                                         mtailp = &(*mtailp)->m_nextpkt;
1094                                 }
1095                                 if (mnext != NULL) {
1096                                         *mtailp = mnext;
1097                                         mtailp = &(*mtailp)->m_nextpkt;
1098                                 }
1099                                 break;
1100 #ifdef INET6
1101                         case 6:
1102                                 if (m != NULL) {
1103                                         *m6_tailp = m;
1104                                         m6_tailp = &(*m6_tailp)->m_nextpkt;
1105                                 }
1106                                 if (mnext != NULL) {
1107                                         *m6_tailp = mnext;
1108                                         m6_tailp = &(*m6_tailp)->m_nextpkt;
1109                                 }
1110                                 break;
1111 #endif
1112                         }
1113
1114                         m = mnext = NULL;
1115                 }
1116         }
1117         IPFW_DYN_UNLOCK();
1118         for (m = mnext = m0; m != NULL; m = mnext) {
1119                 mnext = m->m_nextpkt;
1120                 m->m_nextpkt = NULL;
1121                 ip_output(m, NULL, NULL, 0, NULL, NULL);
1122         }
1123 #ifdef INET6
1124         for (m = mnext = m6; m != NULL; m = mnext) {
1125                 mnext = m->m_nextpkt;
1126                 m->m_nextpkt = NULL;
1127                 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
1128         }
1129 #endif
1130 done:
1131         callout_reset_on(&V_ipfw_timeout, V_dyn_keepalive_period * hz,
1132                       ipfw_tick, vnetx, 0);
1133         CURVNET_RESTORE();
1134 }
1135
1136 void
1137 ipfw_dyn_attach(void)
1138 {
1139         ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule",
1140             sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL,
1141             UMA_ALIGN_PTR, 0);
1142
1143         IPFW_DYN_LOCK_INIT();
1144 }
1145
1146 void
1147 ipfw_dyn_detach(void)
1148 {
1149         uma_zdestroy(ipfw_dyn_rule_zone);
1150         IPFW_DYN_LOCK_DESTROY();
1151 }
1152
1153 void
1154 ipfw_dyn_init(void)
1155 {
1156         V_ipfw_dyn_v = NULL;
1157         V_dyn_buckets = 256;    /* must be power of 2 */
1158         V_curr_dyn_buckets = 256; /* must be power of 2 */
1159
1160         V_dyn_ack_lifetime = 300;
1161         V_dyn_syn_lifetime = 20;
1162         V_dyn_fin_lifetime = 1;
1163         V_dyn_rst_lifetime = 1;
1164         V_dyn_udp_lifetime = 10;
1165         V_dyn_short_lifetime = 5;
1166
1167         V_dyn_keepalive_interval = 20;
1168         V_dyn_keepalive_period = 5;
1169         V_dyn_keepalive = 1;    /* do send keepalives */
1170
1171         V_dyn_max = 4096;       /* max # of dynamic rules */
1172         callout_init(&V_ipfw_timeout, CALLOUT_MPSAFE);
1173         callout_reset_on(&V_ipfw_timeout, hz, ipfw_tick, curvnet, 0);
1174 }
1175
1176 void
1177 ipfw_dyn_uninit(int pass)
1178 {
1179         if (pass == 0)
1180                 callout_drain(&V_ipfw_timeout);
1181         else {
1182                 if (V_ipfw_dyn_v != NULL)
1183                         free(V_ipfw_dyn_v, M_IPFW);
1184         }
1185 }
1186
1187 int
1188 ipfw_dyn_len(void)
1189 {
1190         return (V_ipfw_dyn_v == NULL) ? 0 :
1191                 (V_dyn_count * sizeof(ipfw_dyn_rule));
1192 }
1193
1194 void
1195 ipfw_get_dynamic(char **pbp, const char *ep)
1196 {
1197         ipfw_dyn_rule *p, *last = NULL;
1198         char *bp;
1199         int i;
1200
1201         if (V_ipfw_dyn_v == NULL)
1202                 return;
1203         bp = *pbp;
1204
1205         IPFW_DYN_LOCK();
1206         for (i = 0 ; i < V_curr_dyn_buckets; i++)
1207                 for (p = V_ipfw_dyn_v[i] ; p != NULL; p = p->next) {
1208                         if (bp + sizeof *p <= ep) {
1209                                 ipfw_dyn_rule *dst =
1210                                         (ipfw_dyn_rule *)bp;
1211                                 bcopy(p, dst, sizeof *p);
1212                                 bcopy(&(p->rule->rulenum), &(dst->rule),
1213                                     sizeof(p->rule->rulenum));
1214                                 /*
1215                                  * store set number into high word of
1216                                  * dst->rule pointer.
1217                                  */
1218                                 bcopy(&(p->rule->set),
1219                                     (char *)&dst->rule +
1220                                     sizeof(p->rule->rulenum),
1221                                     sizeof(p->rule->set));
1222                                 /*
1223                                  * store a non-null value in "next".
1224                                  * The userland code will interpret a
1225                                  * NULL here as a marker
1226                                  * for the last dynamic rule.
1227                                  */
1228                                 bcopy(&dst, &dst->next, sizeof(dst));
1229                                 last = dst;
1230                                 dst->expire =
1231                                     TIME_LEQ(dst->expire, time_uptime) ?
1232                                         0 : dst->expire - time_uptime ;
1233                                 bp += sizeof(ipfw_dyn_rule);
1234                         }
1235                 }
1236         IPFW_DYN_UNLOCK();
1237         if (last != NULL) /* mark last dynamic rule */
1238                 bzero(&last->next, sizeof(last));
1239         *pbp = bp;
1240 }
1241 /* end of file */