2 * Copyright (c) 2015 Gleb Smirnoff <glebius@FreeBSD.org>
3 * Copyright (c) 2015 Adrian Chadd <adrian@FreeBSD.org>
4 * Copyright (c) 1982, 1986, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/eventhandler.h>
42 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/limits.h>
48 #include <sys/mutex.h>
49 #include <sys/sysctl.h>
50 #include <sys/socket.h>
53 #include <net/if_var.h>
54 #include <net/rss_config.h>
55 #include <net/netisr.h>
58 #include <netinet/in.h>
59 #include <netinet/ip.h>
60 #include <netinet/ip_var.h>
61 #include <netinet/in_rss.h>
63 #include <security/mac/mac_framework.h>
66 SYSCTL_DECL(_net_inet_ip);
69 * Reassembly headers are stored in hash buckets.
71 #define IPREASS_NHASH_LOG2 10
72 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
73 #define IPREASS_HMASK (IPREASS_NHASH - 1)
76 TAILQ_HEAD(ipqhead, ipq) head;
81 VNET_DEFINE_STATIC(struct ipqbucket, ipq[IPREASS_NHASH]);
82 #define V_ipq VNET(ipq)
83 VNET_DEFINE_STATIC(uint32_t, ipq_hashseed);
84 #define V_ipq_hashseed VNET(ipq_hashseed)
86 #define IPQ_LOCK(i) mtx_lock(&V_ipq[i].lock)
87 #define IPQ_TRYLOCK(i) mtx_trylock(&V_ipq[i].lock)
88 #define IPQ_UNLOCK(i) mtx_unlock(&V_ipq[i].lock)
89 #define IPQ_LOCK_ASSERT(i) mtx_assert(&V_ipq[i].lock, MA_OWNED)
91 VNET_DEFINE_STATIC(int, ipreass_maxbucketsize);
92 #define V_ipreass_maxbucketsize VNET(ipreass_maxbucketsize)
94 void ipreass_init(void);
95 void ipreass_drain(void);
96 void ipreass_slowtimo(void);
98 void ipreass_destroy(void);
100 static int sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS);
101 static int sysctl_maxfragbucketsize(SYSCTL_HANDLER_ARGS);
102 static void ipreass_zone_change(void *);
103 static void ipreass_drain_tomax(void);
104 static void ipq_free(struct ipqbucket *, struct ipq *);
105 static struct ipq * ipq_reuse(int);
108 ipq_timeout(struct ipqbucket *bucket, struct ipq *fp)
111 IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags);
112 ipq_free(bucket, fp);
116 ipq_drop(struct ipqbucket *bucket, struct ipq *fp)
119 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
120 ipq_free(bucket, fp);
124 * By default, limit the number of IP fragments across all reassembly
125 * queues to 1/32 of the total number of mbuf clusters.
127 * Limit the total number of reassembly queues per VNET to the
128 * IP fragment limit, but ensure the limit will not allow any bucket
129 * to grow above 100 items. (The bucket limit is
130 * IP_MAXFRAGPACKETS / (IPREASS_NHASH / 2), so the 50 is the correct
131 * multiplier to reach a 100-item limit.)
132 * The 100-item limit was chosen as brief testing seems to show that
133 * this produces "reasonable" performance on some subset of systems
136 #define IP_MAXFRAGS (nmbclusters / 32)
137 #define IP_MAXFRAGPACKETS (imin(IP_MAXFRAGS, IPREASS_NHASH * 50))
140 static volatile u_int nfrags;
141 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfrags, CTLFLAG_RW,
143 "Maximum number of IPv4 fragments allowed across all reassembly queues");
144 SYSCTL_UINT(_net_inet_ip, OID_AUTO, curfrags, CTLFLAG_RD,
145 __DEVOLATILE(u_int *, &nfrags), 0,
146 "Current number of IPv4 fragments across all reassembly queues");
148 VNET_DEFINE_STATIC(uma_zone_t, ipq_zone);
149 #define V_ipq_zone VNET(ipq_zone)
150 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets,
151 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
152 NULL, 0, sysctl_maxfragpackets, "I",
153 "Maximum number of IPv4 fragment reassembly queue entries");
154 SYSCTL_UMA_CUR(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_VNET,
155 &VNET_NAME(ipq_zone),
156 "Current number of IPv4 fragment reassembly queue entries");
158 VNET_DEFINE_STATIC(int, noreass);
159 #define V_noreass VNET(noreass)
161 VNET_DEFINE_STATIC(int, maxfragsperpacket);
162 #define V_maxfragsperpacket VNET(maxfragsperpacket)
163 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_VNET | CTLFLAG_RW,
164 &VNET_NAME(maxfragsperpacket), 0,
165 "Maximum number of IPv4 fragments allowed per packet");
166 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragbucketsize,
167 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0,
168 sysctl_maxfragbucketsize, "I",
169 "Maximum number of IPv4 fragment reassembly queue entries per bucket");
172 * Take incoming datagram fragment and try to reassemble it into
173 * whole datagram. If the argument is the first fragment or one
174 * in between the function will return NULL and store the mbuf
175 * in the fragment chain. If the argument is the last fragment
176 * the packet will be reassembled and the pointer to the new
177 * mbuf returned for further processing. Only m_tags attached
178 * to the first packet/fragment are preserved.
179 * The IP header is *NOT* adjusted out of iplen.
181 #define M_IP_FRAG M_PROTO9
183 ip_reass(struct mbuf *m)
186 struct mbuf *p, *q, *nq, *t;
188 struct ifnet *srcifp;
189 struct ipqhead *head;
190 int i, hlen, next, tmpmax;
192 uint32_t hash, hashkey[3];
194 uint32_t rss_hash, rss_type;
198 * If no reassembling or maxfragsperpacket are 0,
199 * never accept fragments.
200 * Also, drop packet if it would exceed the maximum
201 * number of fragments.
204 if (V_noreass == 1 || V_maxfragsperpacket == 0 ||
205 (tmpmax >= 0 && atomic_load_int(&nfrags) >= (u_int)tmpmax)) {
206 IPSTAT_INC(ips_fragments);
207 IPSTAT_INC(ips_fragdropped);
212 ip = mtod(m, struct ip *);
213 hlen = ip->ip_hl << 2;
216 * Adjust ip_len to not reflect header,
217 * convert offset of this to bytes.
219 ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
221 * Make sure that fragments have a data length
222 * that's a non-zero multiple of 8 bytes, unless
223 * this is the last fragment.
225 if (ip->ip_len == htons(0) ||
226 ((ip->ip_off & htons(IP_MF)) && (ntohs(ip->ip_len) & 0x7) != 0)) {
227 IPSTAT_INC(ips_toosmall); /* XXX */
228 IPSTAT_INC(ips_fragdropped);
232 if (ip->ip_off & htons(IP_MF))
233 m->m_flags |= M_IP_FRAG;
235 m->m_flags &= ~M_IP_FRAG;
236 ip->ip_off = htons(ntohs(ip->ip_off) << 3);
239 * Make sure the fragment lies within a packet of valid size.
241 if (ntohs(ip->ip_len) + ntohs(ip->ip_off) > IP_MAXPACKET) {
242 IPSTAT_INC(ips_toolong);
243 IPSTAT_INC(ips_fragdropped);
249 * Store receive network interface pointer for later.
251 srcifp = m->m_pkthdr.rcvif;
254 * Attempt reassembly; if it succeeds, proceed.
255 * ip_reass() will return a different mbuf.
257 IPSTAT_INC(ips_fragments);
258 m->m_pkthdr.PH_loc.ptr = ip;
261 * Presence of header sizes in mbufs
262 * would confuse code below.
267 hashkey[0] = ip->ip_src.s_addr;
268 hashkey[1] = ip->ip_dst.s_addr;
269 hashkey[2] = (uint32_t)ip->ip_p << 16;
270 hashkey[2] += ip->ip_id;
271 hash = jenkins_hash32(hashkey, nitems(hashkey), V_ipq_hashseed);
272 hash &= IPREASS_HMASK;
273 head = &V_ipq[hash].head;
277 * Look for queue of fragments
280 TAILQ_FOREACH(fp, head, ipq_list)
281 if (ip->ip_id == fp->ipq_id &&
282 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
283 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
285 mac_ipq_match(m, fp) &&
287 ip->ip_p == fp->ipq_p)
290 * If first fragment to arrive, create a reassembly queue.
293 if (V_ipq[hash].count < V_ipreass_maxbucketsize)
294 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
296 fp = ipq_reuse(hash);
300 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
301 uma_zfree(V_ipq_zone, fp);
305 mac_ipq_create(m, fp);
307 TAILQ_INSERT_HEAD(head, fp, ipq_list);
310 atomic_add_int(&nfrags, 1);
311 fp->ipq_ttl = IPFRAGTTL;
312 fp->ipq_p = ip->ip_p;
313 fp->ipq_id = ip->ip_id;
314 fp->ipq_src = ip->ip_src;
315 fp->ipq_dst = ip->ip_dst;
317 if (m->m_flags & M_IP_FRAG)
320 fp->ipq_maxoff = ntohs(ip->ip_off) + ntohs(ip->ip_len);
325 * If we already saw the last fragment, make sure
326 * this fragment's offset looks sane. Otherwise, if
327 * this is the last fragment, record its endpoint.
329 if (fp->ipq_maxoff > 0) {
330 i = ntohs(ip->ip_off) + ntohs(ip->ip_len);
331 if (((m->m_flags & M_IP_FRAG) && i >= fp->ipq_maxoff) ||
332 ((m->m_flags & M_IP_FRAG) == 0 &&
333 i != fp->ipq_maxoff)) {
337 } else if ((m->m_flags & M_IP_FRAG) == 0)
338 fp->ipq_maxoff = ntohs(ip->ip_off) + ntohs(ip->ip_len);
340 atomic_add_int(&nfrags, 1);
342 mac_ipq_update(m, fp);
346 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr))
349 * Handle ECN by comparing this segment with the first one;
350 * if CE is set, do not lose CE.
351 * drop if CE and not-ECT are mixed for the same packet.
353 ecn = ip->ip_tos & IPTOS_ECN_MASK;
354 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
355 if (ecn == IPTOS_ECN_CE) {
356 if (ecn0 == IPTOS_ECN_NOTECT)
358 if (ecn0 != IPTOS_ECN_CE)
359 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
361 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
365 * Find a segment which begins after this one does.
367 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
368 if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off))
372 * If there is a preceding segment, it may provide some of
373 * our data already. If so, drop the data from the incoming
374 * segment. If it provides all of our data, drop us, otherwise
375 * stick new segment in the proper place.
377 * If some of the data is dropped from the preceding
378 * segment, then it's checksum is invalidated.
381 i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) -
384 if (i >= ntohs(ip->ip_len))
387 m->m_pkthdr.csum_flags = 0;
388 ip->ip_off = htons(ntohs(ip->ip_off) + i);
389 ip->ip_len = htons(ntohs(ip->ip_len) - i);
391 m->m_nextpkt = p->m_nextpkt;
394 m->m_nextpkt = fp->ipq_frags;
399 * While we overlap succeeding segments trim them or,
400 * if they are completely covered, dequeue them.
402 for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) >
403 ntohs(GETIP(q)->ip_off); q = nq) {
404 i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) -
405 ntohs(GETIP(q)->ip_off);
406 if (i < ntohs(GETIP(q)->ip_len)) {
407 GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i);
408 GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i);
410 q->m_pkthdr.csum_flags = 0;
415 IPSTAT_INC(ips_fragdropped);
417 atomic_subtract_int(&nfrags, 1);
422 * Check for complete reassembly and perform frag per packet
425 * Frag limiting is performed here so that the nth frag has
426 * a chance to complete the packet before we drop the packet.
427 * As a result, n+1 frags are actually allowed per packet, but
428 * only n will ever be stored. (n = maxfragsperpacket.)
432 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
433 if (ntohs(GETIP(q)->ip_off) != next) {
434 if (fp->ipq_nfrags > V_maxfragsperpacket)
435 ipq_drop(&V_ipq[hash], fp);
438 next += ntohs(GETIP(q)->ip_len);
440 /* Make sure the last packet didn't have the IP_MF flag */
441 if (p->m_flags & M_IP_FRAG) {
442 if (fp->ipq_nfrags > V_maxfragsperpacket)
443 ipq_drop(&V_ipq[hash], fp);
448 * Reassembly is complete. Make sure the packet is a sane size.
452 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
453 IPSTAT_INC(ips_toolong);
454 ipq_drop(&V_ipq[hash], fp);
459 * Concatenate fragments.
467 for (q = nq; q != NULL; q = nq) {
470 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
471 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
476 * In order to do checksumming faster we do 'end-around carry' here
477 * (and not in for{} loop), though it implies we are not going to
478 * reassemble more than 64k fragments.
480 while (m->m_pkthdr.csum_data & 0xffff0000)
481 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) +
482 (m->m_pkthdr.csum_data >> 16);
483 atomic_subtract_int(&nfrags, fp->ipq_nfrags);
485 mac_ipq_reassemble(fp, m);
490 * Create header for new ip packet by modifying header of first
491 * packet; dequeue and discard fragment reassembly header.
492 * Make header visible.
494 ip->ip_len = htons((ip->ip_hl << 2) + next);
495 ip->ip_src = fp->ipq_src;
496 ip->ip_dst = fp->ipq_dst;
497 TAILQ_REMOVE(head, fp, ipq_list);
499 uma_zfree(V_ipq_zone, fp);
500 m->m_len += (ip->ip_hl << 2);
501 m->m_data -= (ip->ip_hl << 2);
502 /* some debugging cruft by sklower, below, will go away soon */
503 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
505 /* set valid receive interface pointer */
506 m->m_pkthdr.rcvif = srcifp;
508 IPSTAT_INC(ips_reassembled);
513 * Query the RSS layer for the flowid / flowtype for the
516 * For now, just assume we have to calculate a new one.
517 * Later on we should check to see if the assigned flowid matches
518 * what RSS wants for the given IP protocol and if so, just keep it.
520 * We then queue into the relevant netisr so it can be dispatched
521 * to the correct CPU.
523 * Note - this may return 1, which means the flowid in the mbuf
524 * is correct for the configured RSS hash types and can be used.
526 if (rss_mbuf_software_hash_v4(m, 0, &rss_hash, &rss_type) == 0) {
527 m->m_pkthdr.flowid = rss_hash;
528 M_HASHTYPE_SET(m, rss_type);
532 * Queue/dispatch for reprocessing.
534 * Note: this is much slower than just handling the frame in the
535 * current receive context. It's likely worth investigating
538 netisr_dispatch(NETISR_IP_DIRECT, m);
546 IPSTAT_INC(ips_fragdropped);
549 atomic_subtract_int(&nfrags, 1);
560 * Initialize IP reassembly structures.
567 for (int i = 0; i < IPREASS_NHASH; i++) {
568 TAILQ_INIT(&V_ipq[i].head);
569 mtx_init(&V_ipq[i].lock, "IP reassembly", NULL,
570 MTX_DEF | MTX_DUPOK);
573 V_ipq_hashseed = arc4random();
574 V_maxfragsperpacket = 16;
575 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
576 NULL, UMA_ALIGN_PTR, 0);
577 max = IP_MAXFRAGPACKETS;
578 max = uma_zone_set_max(V_ipq_zone, max);
579 V_ipreass_maxbucketsize = imax(max / (IPREASS_NHASH / 2), 1);
581 if (IS_DEFAULT_VNET(curvnet)) {
582 maxfrags = IP_MAXFRAGS;
583 EVENTHANDLER_REGISTER(nmbclusters_change, ipreass_zone_change,
584 NULL, EVENTHANDLER_PRI_ANY);
589 * If a timer expires on a reassembly queue, discard it.
592 ipreass_slowtimo(void)
594 struct ipq *fp, *tmp;
596 for (int i = 0; i < IPREASS_NHASH; i++) {
598 TAILQ_FOREACH_SAFE(fp, &V_ipq[i].head, ipq_list, tmp)
599 if (--fp->ipq_ttl == 0)
600 ipq_timeout(&V_ipq[i], fp);
606 * Drain off all datagram fragments.
612 for (int i = 0; i < IPREASS_NHASH; i++) {
614 while(!TAILQ_EMPTY(&V_ipq[i].head))
615 ipq_drop(&V_ipq[i], TAILQ_FIRST(&V_ipq[i].head));
616 KASSERT(V_ipq[i].count == 0,
617 ("%s: V_ipq[%d] count %d (V_ipq=%p)", __func__, i,
618 V_ipq[i].count, V_ipq));
624 * Drain off all datagram fragments belonging to
625 * the given network interface.
628 ipreass_cleanup(void *arg __unused, struct ifnet *ifp)
630 struct ipq *fp, *temp;
634 KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__));
636 CURVNET_SET_QUIET(ifp->if_vnet);
639 * Skip processing if IPv4 reassembly is not initialised or
640 * torn down by ipreass_destroy().
642 if (V_ipq_zone == NULL) {
647 for (i = 0; i < IPREASS_NHASH; i++) {
649 /* Scan fragment list. */
650 TAILQ_FOREACH_SAFE(fp, &V_ipq[i].head, ipq_list, temp) {
651 for (m = fp->ipq_frags; m != NULL; m = m->m_nextpkt) {
652 /* clear no longer valid rcvif pointer */
653 if (m->m_pkthdr.rcvif == ifp)
654 m->m_pkthdr.rcvif = NULL;
661 EVENTHANDLER_DEFINE(ifnet_departure_event, ipreass_cleanup, NULL, 0);
665 * Destroy IP reassembly structures.
668 ipreass_destroy(void)
672 uma_zdestroy(V_ipq_zone);
674 for (int i = 0; i < IPREASS_NHASH; i++)
675 mtx_destroy(&V_ipq[i].lock);
680 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
681 * max has slightly different semantics than the sysctl, for historical
685 ipreass_drain_tomax(void)
691 * Make sure each bucket is under the new limit. If
692 * necessary, drop enough of the oldest elements from
693 * each bucket to get under the new limit.
695 for (int i = 0; i < IPREASS_NHASH; i++) {
697 while (V_ipq[i].count > V_ipreass_maxbucketsize &&
698 (fp = TAILQ_LAST(&V_ipq[i].head, ipqhead)) != NULL)
699 ipq_timeout(&V_ipq[i], fp);
704 * If we are over the maximum number of fragments,
705 * drain off enough to get down to the new limit,
706 * stripping off last elements on queues. Every
707 * run we strip the oldest element from each bucket.
709 target = uma_zone_get_max(V_ipq_zone);
710 while (uma_zone_get_cur(V_ipq_zone) > target) {
711 for (int i = 0; i < IPREASS_NHASH; i++) {
713 fp = TAILQ_LAST(&V_ipq[i].head, ipqhead);
715 ipq_timeout(&V_ipq[i], fp);
722 ipreass_zone_change(void *tag)
724 VNET_ITERATOR_DECL(vnet_iter);
727 maxfrags = IP_MAXFRAGS;
728 max = IP_MAXFRAGPACKETS;
729 VNET_LIST_RLOCK_NOSLEEP();
730 VNET_FOREACH(vnet_iter) {
731 CURVNET_SET(vnet_iter);
732 max = uma_zone_set_max(V_ipq_zone, max);
733 V_ipreass_maxbucketsize = imax(max / (IPREASS_NHASH / 2), 1);
734 ipreass_drain_tomax();
737 VNET_LIST_RUNLOCK_NOSLEEP();
741 * Change the limit on the UMA zone, or disable the fragment allocation
742 * at all. Since 0 and -1 is a special values here, we need our own handler,
743 * instead of sysctl_handle_uma_zone_max().
746 sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS)
750 if (V_noreass == 0) {
751 max = uma_zone_get_max(V_ipq_zone);
756 error = sysctl_handle_int(oidp, &max, 0, req);
757 if (error || !req->newptr)
761 * XXXRW: Might be a good idea to sanity check the argument
762 * and place an extreme upper bound.
764 max = uma_zone_set_max(V_ipq_zone, max);
765 V_ipreass_maxbucketsize = imax(max / (IPREASS_NHASH / 2), 1);
766 ipreass_drain_tomax();
768 } else if (max == 0) {
771 } else if (max == -1) {
773 uma_zone_set_max(V_ipq_zone, 0);
774 V_ipreass_maxbucketsize = INT_MAX;
781 * Seek for old fragment queue header that can be reused. Try to
782 * reuse a header from currently locked hash bucket.
790 IPQ_LOCK_ASSERT(start);
792 for (i = 0; i < IPREASS_NHASH; i++) {
793 bucket = (start + i) % IPREASS_NHASH;
794 if (bucket != start && IPQ_TRYLOCK(bucket) == 0)
796 fp = TAILQ_LAST(&V_ipq[bucket].head, ipqhead);
800 IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags);
801 atomic_subtract_int(&nfrags, fp->ipq_nfrags);
802 while (fp->ipq_frags) {
804 fp->ipq_frags = m->m_nextpkt;
807 TAILQ_REMOVE(&V_ipq[bucket].head, fp, ipq_list);
808 V_ipq[bucket].count--;
816 IPQ_LOCK_ASSERT(start);
821 * Free a fragment reassembly header and all associated datagrams.
824 ipq_free(struct ipqbucket *bucket, struct ipq *fp)
828 atomic_subtract_int(&nfrags, fp->ipq_nfrags);
829 while (fp->ipq_frags) {
831 fp->ipq_frags = q->m_nextpkt;
834 TAILQ_REMOVE(&bucket->head, fp, ipq_list);
836 uma_zfree(V_ipq_zone, fp);
840 * Get or set the maximum number of reassembly queues per bucket.
843 sysctl_maxfragbucketsize(SYSCTL_HANDLER_ARGS)
847 max = V_ipreass_maxbucketsize;
848 error = sysctl_handle_int(oidp, &max, 0, req);
849 if (error || !req->newptr)
853 V_ipreass_maxbucketsize = max;
854 ipreass_drain_tomax();