2 * Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
33 * Dynamic rule support for ipfw
39 #error IPFIREWALL requires INET.
41 #include "opt_inet6.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/malloc.h>
47 #include <sys/kernel.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 */
56 #include <net/if_var.h>
59 #include <netinet/in.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_var.h> /* ip_defttl */
62 #include <netinet/ip_fw.h>
63 #include <netinet/tcp_var.h>
64 #include <netinet/udp.h>
66 #include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */
68 #include <netinet6/in6_var.h>
69 #include <netinet6/ip6_var.h>
72 #include <netpfil/ipfw/ip_fw_private.h>
74 #include <machine/in_cksum.h> /* XXX for in_cksum */
77 #include <security/mac/mac_framework.h>
81 * Description of dynamic rules.
83 * Dynamic rules are stored in lists accessed through a hash table
84 * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
85 * be modified through the sysctl variable dyn_buckets which is
86 * updated when the table becomes empty.
88 * XXX currently there is only one list, ipfw_dyn.
90 * When a packet is received, its address fields are first masked
91 * with the mask defined for the rule, then hashed, then matched
92 * against the entries in the corresponding list.
93 * Dynamic rules can be used for different purposes:
95 * + enforcing limits on the number of sessions;
96 * + in-kernel NAT (not implemented yet)
98 * The lifetime of dynamic rules is regulated by dyn_*_lifetime,
99 * measured in seconds and depending on the flags.
101 * The total number of dynamic rules is equal to UMA zone items count.
102 * The max number of dynamic rules is dyn_max. When we reach
103 * the maximum number of rules we do not create anymore. This is
104 * done to avoid consuming too much memory, but also too much
105 * time when searching on each packet (ideally, we should try instead
106 * to put a limit on the length of the list on each bucket...).
108 * Each dynamic rule holds a pointer to the parent ipfw rule so
109 * we know what action to perform. Dynamic rules are removed when
110 * the parent rule is deleted. This can be changed by dyn_keep_states
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!!!
118 struct ipfw_dyn_bucket {
119 struct mtx mtx; /* Bucket protecting lock */
120 ipfw_dyn_rule *head; /* Pointer to first rule */
124 * Static variables followed by global ones
126 static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v);
127 static VNET_DEFINE(u_int32_t, dyn_buckets_max);
128 static VNET_DEFINE(u_int32_t, curr_dyn_buckets);
129 static VNET_DEFINE(struct callout, ipfw_timeout);
130 #define V_ipfw_dyn_v VNET(ipfw_dyn_v)
131 #define V_dyn_buckets_max VNET(dyn_buckets_max)
132 #define V_curr_dyn_buckets VNET(curr_dyn_buckets)
133 #define V_ipfw_timeout VNET(ipfw_timeout)
135 static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone);
136 #define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone)
138 #define IPFW_BUCK_LOCK_INIT(b) \
139 mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF)
140 #define IPFW_BUCK_LOCK_DESTROY(b) \
141 mtx_destroy(&(b)->mtx)
142 #define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx)
143 #define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx)
144 #define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED)
147 static VNET_DEFINE(int, dyn_keep_states);
148 #define V_dyn_keep_states VNET(dyn_keep_states)
151 * Timeouts for various events in handing dynamic rules.
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);
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)
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.
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 static VNET_DEFINE(time_t, dyn_keepalive_last);
180 #define V_dyn_keepalive_interval VNET(dyn_keepalive_interval)
181 #define V_dyn_keepalive_period VNET(dyn_keepalive_period)
182 #define V_dyn_keepalive VNET(dyn_keepalive)
183 #define V_dyn_keepalive_last VNET(dyn_keepalive_last)
185 static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */
187 #define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone)
188 #define V_dyn_max VNET(dyn_max)
190 /* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */
191 static int ipfw_dyn_count; /* number of objects */
193 #ifdef USERSPACE /* emulation of UMA object counters for userspace */
194 #define uma_zone_get_cur(x) ipfw_dyn_count
195 #endif /* USERSPACE */
197 static int last_log; /* Log ratelimiting */
199 static void ipfw_dyn_tick(void *vnetx);
200 static void check_dyn_rules(struct ip_fw_chain *, ipfw_range_tlv *, int, int);
203 static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS);
204 static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS);
208 SYSCTL_DECL(_net_inet_ip_fw);
209 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets,
210 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0,
211 "Max number of dyn. buckets");
212 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets,
213 CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0,
214 "Current Number of dyn. buckets");
215 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count,
216 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU",
217 "Number of dyn. rules");
218 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max,
219 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU",
220 "Max number of dyn. rules");
221 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime,
222 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0,
223 "Lifetime of dyn. rules for acks");
224 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime,
225 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0,
226 "Lifetime of dyn. rules for syn");
227 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime,
228 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0,
229 "Lifetime of dyn. rules for fin");
230 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime,
231 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0,
232 "Lifetime of dyn. rules for rst");
233 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime,
234 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0,
235 "Lifetime of dyn. rules for UDP");
236 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime,
237 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0,
238 "Lifetime of dyn. rules for other situations");
239 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive,
240 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0,
241 "Enable keepalives for dyn. rules");
242 SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states,
243 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0,
244 "Do not flush dynamic states on rule deletion");
248 #endif /* SYSCTL_NODE */
253 hash_packet6(struct ipfw_flow_id *id)
256 i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^
257 (id->dst_ip6.__u6_addr.__u6_addr32[3]) ^
258 (id->src_ip6.__u6_addr.__u6_addr32[2]) ^
259 (id->src_ip6.__u6_addr.__u6_addr32[3]) ^
260 (id->dst_port) ^ (id->src_port);
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.
271 hash_packet(struct ipfw_flow_id *id, int buckets)
276 if (IS_IP6_FLOW_ID(id))
277 i = hash_packet6(id);
280 i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
286 * Print customizable flow id description via log(9) facility.
289 print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags,
290 char *prefix, char *postfix)
294 char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
296 char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN];
300 if (IS_IP6_FLOW_ID(id)) {
301 ip6_sprintf(src, &id->src_ip6);
302 ip6_sprintf(dst, &id->dst_ip6);
306 da.s_addr = htonl(id->src_ip);
307 inet_ntop(AF_INET, &da, src, sizeof(src));
308 da.s_addr = htonl(id->dst_ip);
309 inet_ntop(AF_INET, &da, dst, sizeof(dst));
311 log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n",
312 prefix, dyn_type, src, id->src_port, dst,
313 id->dst_port, DYN_COUNT, postfix);
316 #define print_dyn_rule(id, dtype, prefix, postfix) \
317 print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix)
319 #define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0)
320 #define TIME_LE(a,b) ((int)((a)-(b)) < 0)
323 * Lookup a dynamic rule, locked version.
325 static ipfw_dyn_rule *
326 lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction,
330 * Stateful ipfw extensions.
331 * Lookup into dynamic session queue.
333 #define MATCH_REVERSE 0
334 #define MATCH_FORWARD 1
336 #define MATCH_UNKNOWN 3
337 int dir = MATCH_NONE;
338 ipfw_dyn_rule *prev, *q = NULL;
342 for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) {
343 if (q->dyn_type == O_LIMIT_PARENT && q->count)
346 if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT)
349 if (IS_IP6_FLOW_ID(pkt)) {
350 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) &&
351 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) &&
352 pkt->src_port == q->id.src_port &&
353 pkt->dst_port == q->id.dst_port) {
357 if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) &&
358 IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) &&
359 pkt->src_port == q->id.dst_port &&
360 pkt->dst_port == q->id.src_port) {
365 if (pkt->src_ip == q->id.src_ip &&
366 pkt->dst_ip == q->id.dst_ip &&
367 pkt->src_port == q->id.src_port &&
368 pkt->dst_port == q->id.dst_port) {
372 if (pkt->src_ip == q->id.dst_ip &&
373 pkt->dst_ip == q->id.src_ip &&
374 pkt->src_port == q->id.dst_port &&
375 pkt->dst_port == q->id.src_port) {
382 goto done; /* q = NULL, not found */
384 if (prev != NULL) { /* found and not in front */
385 prev->next = q->next;
386 q->next = V_ipfw_dyn_v[i].head;
387 V_ipfw_dyn_v[i].head = q;
389 if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */
391 u_char flags = pkt->_flags & (TH_FIN | TH_SYN | TH_RST);
393 #define BOTH_SYN (TH_SYN | (TH_SYN << 8))
394 #define BOTH_FIN (TH_FIN | (TH_FIN << 8))
395 #define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8))
396 #define ACK_FWD 0x10000 /* fwd ack seen */
397 #define ACK_REV 0x20000 /* rev ack seen */
399 q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8);
400 switch (q->state & TCP_FLAGS) {
401 case TH_SYN: /* opening */
402 q->expire = time_uptime + V_dyn_syn_lifetime;
405 case BOTH_SYN: /* move to established */
406 case BOTH_SYN | TH_FIN: /* one side tries to close */
407 case BOTH_SYN | (TH_FIN << 8):
408 #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
412 ack = ntohl(tcp->th_ack);
413 if (dir == MATCH_FORWARD) {
414 if (q->ack_fwd == 0 ||
415 _SEQ_GE(ack, q->ack_fwd)) {
420 if (q->ack_rev == 0 ||
421 _SEQ_GE(ack, q->ack_rev)) {
426 if ((q->state & (ACK_FWD | ACK_REV)) ==
427 (ACK_FWD | ACK_REV)) {
428 q->expire = time_uptime + V_dyn_ack_lifetime;
429 q->state &= ~(ACK_FWD | ACK_REV);
433 case BOTH_SYN | BOTH_FIN: /* both sides closed */
434 if (V_dyn_fin_lifetime >= V_dyn_keepalive_period)
435 V_dyn_fin_lifetime = V_dyn_keepalive_period - 1;
436 q->expire = time_uptime + V_dyn_fin_lifetime;
442 * reset or some invalid combination, but can also
443 * occur if we use keep-state the wrong way.
445 if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
446 printf("invalid state: 0x%x\n", q->state);
448 if (V_dyn_rst_lifetime >= V_dyn_keepalive_period)
449 V_dyn_rst_lifetime = V_dyn_keepalive_period - 1;
450 q->expire = time_uptime + V_dyn_rst_lifetime;
453 } else if (pkt->proto == IPPROTO_UDP) {
454 q->expire = time_uptime + V_dyn_udp_lifetime;
456 /* other protocols */
457 q->expire = time_uptime + V_dyn_short_lifetime;
460 if (match_direction != NULL)
461 *match_direction = dir;
466 ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction,
472 i = hash_packet(pkt, V_curr_dyn_buckets);
475 q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp);
478 /* NB: return table locked when q is not NULL */
484 * @p - pointer to dynamic rule
487 ipfw_dyn_unlock(ipfw_dyn_rule *q)
490 IPFW_BUCK_UNLOCK(q->bucket);
494 resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets)
496 int i, k, nbuckets_old;
498 struct ipfw_dyn_bucket *dyn_v, *dyn_v_old;
500 /* Check if given number is power of 2 and less than 64k */
501 if ((nbuckets > 65536) || (!powerof2(nbuckets)))
504 CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__,
505 V_curr_dyn_buckets, nbuckets);
507 /* Allocate and initialize new hash */
508 dyn_v = malloc(nbuckets * sizeof(ipfw_dyn_rule), M_IPFW,
511 for (i = 0 ; i < nbuckets; i++)
512 IPFW_BUCK_LOCK_INIT(&dyn_v[i]);
515 * Call upper half lock, as get_map() do to ease
516 * read-only access to dynamic rules hash from sysctl
518 IPFW_UH_WLOCK(chain);
521 * Acquire chain write lock to permit hash access
522 * for main traffic path without additional locks
526 /* Save old values */
527 nbuckets_old = V_curr_dyn_buckets;
528 dyn_v_old = V_ipfw_dyn_v;
530 /* Skip relinking if array is not set up */
531 if (V_ipfw_dyn_v == NULL)
532 V_curr_dyn_buckets = 0;
534 /* Re-link all dynamic states */
535 for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
536 while (V_ipfw_dyn_v[i].head != NULL) {
537 /* Remove from current chain */
538 q = V_ipfw_dyn_v[i].head;
539 V_ipfw_dyn_v[i].head = q->next;
541 /* Get new hash value */
542 k = hash_packet(&q->id, nbuckets);
544 /* Add to the new head */
545 q->next = dyn_v[k].head;
550 /* Update current pointers/buckets values */
551 V_curr_dyn_buckets = nbuckets;
552 V_ipfw_dyn_v = dyn_v;
556 IPFW_UH_WUNLOCK(chain);
558 /* Start periodic callout on initial creation */
559 if (dyn_v_old == NULL) {
560 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0);
564 /* Destroy all mutexes */
565 for (i = 0 ; i < nbuckets_old ; i++)
566 IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]);
569 free(dyn_v_old, M_IPFW);
575 * Install state of type 'type' for a dynamic session.
576 * The hash table contains two type of rules:
577 * - regular rules (O_KEEP_STATE)
578 * - rules for sessions with limited number of sess per user
579 * (O_LIMIT). When they are created, the parent is
580 * increased by 1, and decreased on delete. In this case,
581 * the third parameter is the parent rule and not the chain.
582 * - "parent" rules for the above (O_LIMIT_PARENT).
584 static ipfw_dyn_rule *
585 add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule)
591 r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO);
593 if (last_log != time_uptime) {
594 last_log = time_uptime;
596 "ipfw: Cannot allocate dynamic state, "
597 "consider increasing net.inet.ip.fw.dyn_max\n");
604 * refcount on parent is already incremented, so
605 * it is safe to use parent unlocked.
607 if (dyn_type == O_LIMIT) {
608 ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule;
609 if ( parent->dyn_type != O_LIMIT_PARENT)
610 panic("invalid parent");
616 r->expire = time_uptime + V_dyn_syn_lifetime;
618 r->dyn_type = dyn_type;
619 IPFW_ZERO_DYN_COUNTER(r);
623 r->next = V_ipfw_dyn_v[i].head;
624 V_ipfw_dyn_v[i].head = r;
625 DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");)
630 * lookup dynamic parent rule using pkt and rule as search keys.
631 * If the lookup fails, then install one.
633 static ipfw_dyn_rule *
634 lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule)
639 is_v6 = IS_IP6_FLOW_ID(pkt);
640 i = hash_packet( pkt, V_curr_dyn_buckets );
643 for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next)
644 if (q->dyn_type == O_LIMIT_PARENT &&
646 pkt->proto == q->id.proto &&
647 pkt->src_port == q->id.src_port &&
648 pkt->dst_port == q->id.dst_port &&
651 IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6),
653 IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6),
654 &(q->id.dst_ip6))) ||
656 pkt->src_ip == q->id.src_ip &&
657 pkt->dst_ip == q->id.dst_ip)
660 q->expire = time_uptime + V_dyn_short_lifetime;
661 DEB(print_dyn_rule(pkt, q->dyn_type,
662 "lookup_dyn_parent found", "");)
666 /* Add virtual limiting rule */
667 return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule);
671 * Install dynamic state for rule type cmd->o.opcode
673 * Returns 1 (failure) if state is not installed because of errors or because
674 * session limitations are enforced.
677 ipfw_install_state(struct ip_fw_chain *chain, struct ip_fw *rule,
678 ipfw_insn_limit *cmd, struct ip_fw_args *args, uint32_t tablearg)
683 DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");)
685 i = hash_packet(&args->f_id, V_curr_dyn_buckets);
689 q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL);
691 if (q != NULL) { /* should never occur */
693 if (last_log != time_uptime) {
694 last_log = time_uptime;
695 printf("ipfw: %s: entry already present, done\n",
703 * State limiting is done via uma(9) zone limiting.
704 * Save pointer to newly-installed rule and reject
705 * packet if add_dyn_rule() returned NULL.
706 * Note q is currently set to NULL.
709 switch (cmd->o.opcode) {
710 case O_KEEP_STATE: /* bidir rule */
711 q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule);
714 case O_LIMIT: { /* limit number of sessions */
715 struct ipfw_flow_id id;
716 ipfw_dyn_rule *parent;
718 uint16_t limit_mask = cmd->limit_mask;
721 conn_limit = IP_FW_ARG_TABLEARG(chain, cmd->conn_limit, limit);
724 if (cmd->conn_limit == IP_FW_TARG)
725 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u "
726 "(tablearg)\n", __func__, conn_limit);
728 printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n",
729 __func__, conn_limit);
732 id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0;
733 id.proto = args->f_id.proto;
734 id.addr_type = args->f_id.addr_type;
735 id.fib = M_GETFIB(args->m);
737 if (IS_IP6_FLOW_ID (&(args->f_id))) {
738 if (limit_mask & DYN_SRC_ADDR)
739 id.src_ip6 = args->f_id.src_ip6;
740 if (limit_mask & DYN_DST_ADDR)
741 id.dst_ip6 = args->f_id.dst_ip6;
743 if (limit_mask & DYN_SRC_ADDR)
744 id.src_ip = args->f_id.src_ip;
745 if (limit_mask & DYN_DST_ADDR)
746 id.dst_ip = args->f_id.dst_ip;
748 if (limit_mask & DYN_SRC_PORT)
749 id.src_port = args->f_id.src_port;
750 if (limit_mask & DYN_DST_PORT)
751 id.dst_port = args->f_id.dst_port;
754 * We have to release lock for previous bucket to
755 * avoid possible deadlock
759 if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) {
760 printf("ipfw: %s: add parent failed\n", __func__);
761 IPFW_BUCK_UNLOCK(pindex);
765 if (parent->count >= conn_limit) {
766 if (V_fw_verbose && last_log != time_uptime) {
767 last_log = time_uptime;
769 last_log = time_uptime;
770 snprintf(sbuf, sizeof(sbuf),
772 parent->rule->rulenum);
773 print_dyn_rule_flags(&args->f_id,
775 LOG_SECURITY | LOG_DEBUG,
776 sbuf, "too many entries");
778 IPFW_BUCK_UNLOCK(pindex);
781 /* Increment counter on parent */
783 IPFW_BUCK_UNLOCK(pindex);
786 q = add_dyn_rule(&args->f_id, i, O_LIMIT, (struct ip_fw *)parent);
788 /* Decrement index and notify caller */
790 IPFW_BUCK_LOCK(pindex);
792 IPFW_BUCK_UNLOCK(pindex);
798 printf("ipfw: %s: unknown dynamic rule type %u\n",
799 __func__, cmd->o.opcode);
804 return (1); /* Notify caller about failure */
807 /* XXX just set lifetime */
808 lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL);
815 * Generate a TCP packet, containing either a RST or a keepalive.
816 * When flags & TH_RST, we are sending a RST packet, because of a
817 * "reset" action matched the packet.
818 * Otherwise we are sending a keepalive, and flags & TH_
819 * The 'replyto' mbuf is the mbuf being replied to, if any, and is required
820 * so that MAC can label the reply appropriately.
823 ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq,
824 u_int32_t ack, int flags)
826 struct mbuf *m = NULL; /* stupid compiler */
828 struct ip *h = NULL; /* stupid compiler */
830 struct ip6_hdr *h6 = NULL;
832 struct tcphdr *th = NULL;
834 MGETHDR(m, M_NOWAIT, MT_DATA);
838 M_SETFIB(m, id->fib);
841 mac_netinet_firewall_reply(replyto, m);
843 mac_netinet_firewall_send(m);
845 (void)replyto; /* don't warn about unused arg */
848 switch (id->addr_type) {
850 len = sizeof(struct ip) + sizeof(struct tcphdr);
854 len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
862 dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN);
864 m->m_data += max_linkhdr;
865 m->m_flags |= M_SKIP_FIREWALL;
866 m->m_pkthdr.len = m->m_len = len;
867 m->m_pkthdr.rcvif = NULL;
868 bzero(m->m_data, len);
870 switch (id->addr_type) {
872 h = mtod(m, struct ip *);
874 /* prepare for checksum */
875 h->ip_p = IPPROTO_TCP;
876 h->ip_len = htons(sizeof(struct tcphdr));
878 h->ip_src.s_addr = htonl(id->src_ip);
879 h->ip_dst.s_addr = htonl(id->dst_ip);
881 h->ip_src.s_addr = htonl(id->dst_ip);
882 h->ip_dst.s_addr = htonl(id->src_ip);
885 th = (struct tcphdr *)(h + 1);
889 h6 = mtod(m, struct ip6_hdr *);
891 /* prepare for checksum */
892 h6->ip6_nxt = IPPROTO_TCP;
893 h6->ip6_plen = htons(sizeof(struct tcphdr));
895 h6->ip6_src = id->src_ip6;
896 h6->ip6_dst = id->dst_ip6;
898 h6->ip6_src = id->dst_ip6;
899 h6->ip6_dst = id->src_ip6;
902 th = (struct tcphdr *)(h6 + 1);
908 th->th_sport = htons(id->src_port);
909 th->th_dport = htons(id->dst_port);
911 th->th_sport = htons(id->dst_port);
912 th->th_dport = htons(id->src_port);
914 th->th_off = sizeof(struct tcphdr) >> 2;
916 if (flags & TH_RST) {
917 if (flags & TH_ACK) {
918 th->th_seq = htonl(ack);
919 th->th_flags = TH_RST;
923 th->th_ack = htonl(seq);
924 th->th_flags = TH_RST | TH_ACK;
928 * Keepalive - use caller provided sequence numbers
930 th->th_seq = htonl(seq);
931 th->th_ack = htonl(ack);
932 th->th_flags = TH_ACK;
935 switch (id->addr_type) {
937 th->th_sum = in_cksum(m, len);
939 /* finish the ip header */
941 h->ip_hl = sizeof(*h) >> 2;
942 h->ip_tos = IPTOS_LOWDELAY;
943 h->ip_off = htons(0);
944 h->ip_len = htons(len);
945 h->ip_ttl = V_ip_defttl;
950 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6),
951 sizeof(struct tcphdr));
953 /* finish the ip6 header */
954 h6->ip6_vfc |= IPV6_VERSION;
955 h6->ip6_hlim = IPV6_DEFHLIM;
964 * Queue keepalive packets for given dynamic rule
966 static struct mbuf **
967 ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q)
969 struct mbuf *m_rev, *m_fwd;
971 m_rev = (q->state & ACK_REV) ? NULL :
972 ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN);
973 m_fwd = (q->state & ACK_FWD) ? NULL :
974 ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0);
978 mtailp = &(*mtailp)->m_nextpkt;
982 mtailp = &(*mtailp)->m_nextpkt;
989 * This procedure is used to perform various maintance
990 * on dynamic hash list. Currently it is called every second.
993 ipfw_dyn_tick(void * vnetx)
995 struct ip_fw_chain *chain;
998 struct vnet *vp = vnetx;
1003 chain = &V_layer3_chain;
1005 /* Run keepalive checks every keepalive_period iff ka is enabled */
1006 if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) &&
1007 (V_dyn_keepalive != 0)) {
1008 V_dyn_keepalive_last = time_uptime;
1012 check_dyn_rules(chain, NULL, check_ka, 1);
1014 callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0);
1021 * Walk thru all dynamic states doing generic maintance:
1022 * 1) free expired states
1023 * 2) free all states based on deleted rule / set
1024 * 3) send keepalives for states if needed
1026 * @chain - pointer to current ipfw rules chain
1027 * @rule - delete all states originated by given rule if != NULL
1028 * @set - delete all states originated by any rule in set @set if != RESVD_SET
1029 * @check_ka - perform checking/sending keepalives
1030 * @timer - indicate call from timer routine.
1032 * Timer routine must call this function unlocked to permit
1033 * sending keepalives/resizing table.
1035 * Others has to call function with IPFW_UH_WLOCK held.
1036 * Additionally, function assume that dynamic rule/set is
1037 * ALREADY deleted so no new states can be generated by
1040 * Write lock is needed to ensure that unused parent rules
1041 * are not freed by other instance (see stage 2, 3)
1044 check_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt,
1045 int check_ka, int timer)
1047 struct mbuf *m0, *m, *mnext, **mtailp;
1049 int i, dyn_count, new_buckets = 0, max_buckets;
1050 int expired = 0, expired_limits = 0, parents = 0, total = 0;
1051 ipfw_dyn_rule *q, *q_prev, *q_next;
1052 ipfw_dyn_rule *exp_head, **exptailp;
1053 ipfw_dyn_rule *exp_lhead, **expltailp;
1055 KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated",
1058 /* Avoid possible LOR */
1059 KASSERT(!check_ka || timer, ("%s: keepalive check with lock held",
1063 * Do not perform any checks if we currently have no dynamic states
1068 /* Expired states */
1070 exptailp = &exp_head;
1072 /* Expired limit states */
1074 expltailp = &exp_lhead;
1077 * We make a chain of packets to go out here -- not deferring
1078 * until after we drop the IPFW dynamic rule lock would result
1079 * in a lock order reversal with the normal packet input -> ipfw
1085 /* Protect from hash resizing */
1087 IPFW_UH_WLOCK(chain);
1089 IPFW_UH_WLOCK_ASSERT(chain);
1091 #define NEXT_RULE() { q_prev = q; q = q->next ; continue; }
1093 /* Stage 1: perform requested deletion */
1094 for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
1096 for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) {
1097 /* account every rule */
1100 /* Skip parent rules at all */
1101 if (q->dyn_type == O_LIMIT_PARENT) {
1107 * Remove rules which are:
1109 * 2) matches deletion range
1111 if ((TIME_LEQ(q->expire, time_uptime)) ||
1112 (rt != NULL && ipfw_match_range(q->rule, rt))) {
1113 if (TIME_LE(time_uptime, q->expire) &&
1114 q->dyn_type == O_KEEP_STATE &&
1115 V_dyn_keep_states != 0) {
1117 * Do not delete state if
1118 * it is not expired and
1119 * dyn_keep_states is ON.
1120 * However we need to re-link it
1121 * to any other stable rule
1123 q->rule = chain->default_rule;
1127 /* Unlink q from current list */
1129 if (q == V_ipfw_dyn_v[i].head)
1130 V_ipfw_dyn_v[i].head = q_next;
1132 q_prev->next = q_next;
1136 /* queue q to expire list */
1137 if (q->dyn_type != O_LIMIT) {
1139 exptailp = &(*exptailp)->next;
1140 DEB(print_dyn_rule(&q->id, q->dyn_type,
1141 "unlink entry", "left");
1144 /* Separate list for limit rules */
1146 expltailp = &(*expltailp)->next;
1148 DEB(print_dyn_rule(&q->id, q->dyn_type,
1149 "unlink limit entry", "left");
1159 * Check if we need to send keepalive:
1160 * we need to ensure if is time to do KA,
1161 * this is established TCP session, and
1162 * expire time is within keepalive interval
1164 if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) &&
1165 ((q->state & BOTH_SYN) == BOTH_SYN) &&
1166 (TIME_LEQ(q->expire, time_uptime +
1167 V_dyn_keepalive_interval)))
1168 mtailp = ipfw_dyn_send_ka(mtailp, q);
1172 IPFW_BUCK_UNLOCK(i);
1175 /* Stage 2: decrement counters from O_LIMIT parents */
1176 if (expired_limits != 0) {
1178 * XXX: Note that deleting set with more than one
1179 * heavily-used LIMIT rules can result in overwhelming
1180 * locking due to lack of per-hash value sorting
1182 * We should probably think about:
1183 * 1) pre-allocating hash of size, say,
1184 * MAX(16, V_curr_dyn_buckets / 1024)
1185 * 2) checking if expired_limits is large enough
1186 * 3) If yes, init hash (or its part), re-link
1187 * current list and start decrementing procedure in
1188 * each bucket separately
1192 * Small optimization: do not unlock bucket until
1193 * we see the next item resides in different bucket
1195 if (exp_lhead != NULL) {
1196 i = exp_lhead->parent->bucket;
1199 for (q = exp_lhead; q != NULL; q = q->next) {
1200 if (i != q->parent->bucket) {
1201 IPFW_BUCK_UNLOCK(i);
1202 i = q->parent->bucket;
1206 /* Decrease parent refcount */
1209 if (exp_lhead != NULL)
1210 IPFW_BUCK_UNLOCK(i);
1214 * We protectet ourselves from unused parent deletion
1215 * (from the timer function) by holding UH write lock.
1218 /* Stage 3: remove unused parent rules */
1219 if ((parents != 0) && (expired != 0)) {
1220 for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
1222 for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) {
1223 if (q->dyn_type != O_LIMIT_PARENT)
1229 /* Parent rule without consumers */
1231 /* Unlink q from current list */
1233 if (q == V_ipfw_dyn_v[i].head)
1234 V_ipfw_dyn_v[i].head = q_next;
1236 q_prev->next = q_next;
1240 /* Add to expired list */
1242 exptailp = &(*exptailp)->next;
1244 DEB(print_dyn_rule(&q->id, q->dyn_type,
1245 "unlink parent entry", "left");
1252 IPFW_BUCK_UNLOCK(i);
1260 * Check if we need to resize hash:
1261 * if current number of states exceeds number of buckes in hash,
1262 * grow hash size to the minimum power of 2 which is bigger than
1263 * current states count. Limit hash size by 64k.
1265 max_buckets = (V_dyn_buckets_max > 65536) ?
1266 65536 : V_dyn_buckets_max;
1268 dyn_count = DYN_COUNT;
1270 if ((dyn_count > V_curr_dyn_buckets * 2) &&
1271 (dyn_count < max_buckets)) {
1272 new_buckets = V_curr_dyn_buckets;
1273 while (new_buckets < dyn_count) {
1276 if (new_buckets >= max_buckets)
1281 IPFW_UH_WUNLOCK(chain);
1284 /* Finally delete old states ad limits if any */
1285 for (q = exp_head; q != NULL; q = q_next) {
1287 uma_zfree(V_ipfw_dyn_rule_zone, q);
1291 for (q = exp_lhead; q != NULL; q = q_next) {
1293 uma_zfree(V_ipfw_dyn_rule_zone, q);
1298 * The rest code MUST be called from timer routine only
1299 * without holding any locks
1304 /* Send keepalive packets if any */
1305 for (m = m0; m != NULL; m = mnext) {
1306 mnext = m->m_nextpkt;
1307 m->m_nextpkt = NULL;
1308 h = mtod(m, struct ip *);
1310 ip_output(m, NULL, NULL, 0, NULL, NULL);
1313 ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
1317 /* Run table resize without holding any locks */
1318 if (new_buckets != 0)
1319 resize_dynamic_table(chain, new_buckets);
1323 * Deletes all dynamic rules originated by given rule or all rules in
1324 * given set. Specify RESVD_SET to indicate set should not be used.
1325 * @chain - pointer to current ipfw rules chain
1326 * @rr - delete all states originated by rules in matched range.
1328 * Function has to be called with IPFW_UH_WLOCK held.
1329 * Additionally, function assume that dynamic rule/set is
1330 * ALREADY deleted so no new states can be generated by
1334 ipfw_expire_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt)
1337 check_dyn_rules(chain, rt, 0, 0);
1341 * Check if rule contains at least one dynamic opcode.
1343 * Returns 1 if such opcode is found, 0 otherwise.
1346 ipfw_is_dyn_rule(struct ip_fw *rule)
1354 for ( ; l > 0 ; l -= cmdlen, cmd += cmdlen) {
1355 cmdlen = F_LEN(cmd);
1357 switch (cmd->opcode) {
1370 ipfw_dyn_init(struct ip_fw_chain *chain)
1373 V_ipfw_dyn_v = NULL;
1374 V_dyn_buckets_max = 256; /* must be power of 2 */
1375 V_curr_dyn_buckets = 256; /* must be power of 2 */
1377 V_dyn_ack_lifetime = 300;
1378 V_dyn_syn_lifetime = 20;
1379 V_dyn_fin_lifetime = 1;
1380 V_dyn_rst_lifetime = 1;
1381 V_dyn_udp_lifetime = 10;
1382 V_dyn_short_lifetime = 5;
1384 V_dyn_keepalive_interval = 20;
1385 V_dyn_keepalive_period = 5;
1386 V_dyn_keepalive = 1; /* do send keepalives */
1387 V_dyn_keepalive_last = time_uptime;
1389 V_dyn_max = 16384; /* max # of dynamic rules */
1391 V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule",
1392 sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL,
1395 /* Enforce limit on dynamic rules */
1396 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max);
1398 callout_init(&V_ipfw_timeout, CALLOUT_MPSAFE);
1401 * This can potentially be done on first dynamic rule
1402 * being added to chain.
1404 resize_dynamic_table(chain, V_curr_dyn_buckets);
1408 ipfw_dyn_uninit(int pass)
1413 callout_drain(&V_ipfw_timeout);
1417 if (V_ipfw_dyn_v != NULL) {
1419 * Skip deleting all dynamic states -
1420 * uma_zdestroy() does this more efficiently;
1423 /* Destroy all mutexes */
1424 for (i = 0 ; i < V_curr_dyn_buckets ; i++)
1425 IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]);
1426 free(V_ipfw_dyn_v, M_IPFW);
1427 V_ipfw_dyn_v = NULL;
1430 uma_zdestroy(V_ipfw_dyn_rule_zone);
1435 * Get/set maximum number of dynamic states in given VNET instance.
1438 sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS)
1441 unsigned int nstates;
1443 nstates = V_dyn_max;
1445 error = sysctl_handle_int(oidp, &nstates, 0, req);
1446 /* Read operation or some error */
1447 if ((error != 0) || (req->newptr == NULL))
1450 V_dyn_max = nstates;
1451 uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max);
1457 * Get current number of dynamic states in given VNET instance.
1460 sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS)
1463 unsigned int nstates;
1465 nstates = DYN_COUNT;
1467 error = sysctl_handle_int(oidp, &nstates, 0, req);
1474 * Returns size of dynamic states in legacy format
1480 return (V_ipfw_dyn_v == NULL) ? 0 :
1481 (DYN_COUNT * sizeof(ipfw_dyn_rule));
1485 * Returns number of dynamic states.
1486 * Used by dump format v1 (current).
1489 ipfw_dyn_get_count(void)
1492 return (V_ipfw_dyn_v == NULL) ? 0 : DYN_COUNT;
1496 export_dyn_rule(ipfw_dyn_rule *src, ipfw_dyn_rule *dst)
1499 memcpy(dst, src, sizeof(*src));
1500 memcpy(&(dst->rule), &(src->rule->rulenum), sizeof(src->rule->rulenum));
1502 * store set number into high word of
1503 * dst->rule pointer.
1505 memcpy((char *)&dst->rule + sizeof(src->rule->rulenum),
1506 &(src->rule->set), sizeof(src->rule->set));
1508 * store a non-null value in "next".
1509 * The userland code will interpret a
1510 * NULL here as a marker
1511 * for the last dynamic rule.
1513 memcpy(&dst->next, &dst, sizeof(dst));
1515 TIME_LEQ(dst->expire, time_uptime) ? 0 : dst->expire - time_uptime;
1519 * Fills int buffer given by @sd with dynamic states.
1520 * Used by dump format v1 (current).
1522 * Returns 0 on success.
1525 ipfw_dump_states(struct ip_fw_chain *chain, struct sockopt_data *sd)
1528 ipfw_obj_dyntlv *dst, *last;
1529 ipfw_obj_ctlv *ctlv;
1533 if (V_ipfw_dyn_v == NULL)
1536 IPFW_UH_RLOCK_ASSERT(chain);
1538 ctlv = (ipfw_obj_ctlv *)ipfw_get_sopt_space(sd, sizeof(*ctlv));
1541 sz = sizeof(ipfw_obj_dyntlv);
1542 ctlv->head.type = IPFW_TLV_DYNSTATE_LIST;
1546 for (i = 0 ; i < V_curr_dyn_buckets; i++) {
1548 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) {
1549 dst = (ipfw_obj_dyntlv *)ipfw_get_sopt_space(sd, sz);
1551 IPFW_BUCK_UNLOCK(i);
1555 export_dyn_rule(p, &dst->state);
1556 dst->head.length = sz;
1557 dst->head.type = IPFW_TLV_DYN_ENT;
1560 IPFW_BUCK_UNLOCK(i);
1563 if (last != NULL) /* mark last dynamic rule */
1564 last->head.flags = IPFW_DF_LAST;
1570 * Fill given buffer with dynamic states (legacy format).
1571 * IPFW_UH_RLOCK has to be held while calling.
1574 ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep)
1576 ipfw_dyn_rule *p, *last = NULL;
1580 if (V_ipfw_dyn_v == NULL)
1584 IPFW_UH_RLOCK_ASSERT(chain);
1586 for (i = 0 ; i < V_curr_dyn_buckets; i++) {
1588 for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) {
1589 if (bp + sizeof *p <= ep) {
1590 ipfw_dyn_rule *dst =
1591 (ipfw_dyn_rule *)bp;
1593 export_dyn_rule(p, dst);
1595 bp += sizeof(ipfw_dyn_rule);
1598 IPFW_BUCK_UNLOCK(i);
1601 if (last != NULL) /* mark last dynamic rule */
1602 bzero(&last->next, sizeof(last));