2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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 project 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 PROJECT 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 PROJECT 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 * $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/domain.h>
42 #include <sys/eventhandler.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/sysctl.h>
50 #include <sys/syslog.h>
53 #include <net/if_var.h>
54 #include <net/netisr.h>
55 #include <net/route.h>
58 #include <netinet/in.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip6.h>
61 #include <netinet6/ip6_var.h>
62 #include <netinet/icmp6.h>
63 #include <netinet/in_systm.h> /* For ECN definitions. */
64 #include <netinet/ip.h> /* For ECN definitions. */
67 #include <security/mac/mac_framework.h>
70 /* Reassembly headers are stored in hash buckets. */
71 #define IP6REASS_NHASH_LOG2 10
72 #define IP6REASS_NHASH (1 << IP6REASS_NHASH_LOG2)
73 #define IP6REASS_HMASK (IP6REASS_NHASH - 1)
75 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *,
76 uint32_t bucket __unused);
77 static void frag6_deq(struct ip6asfrag *, uint32_t bucket __unused);
78 static void frag6_insque_head(struct ip6q *, struct ip6q *,
80 static void frag6_remque(struct ip6q *, uint32_t bucket);
81 static void frag6_freef(struct ip6q *, uint32_t bucket);
90 struct ip6asfrag *ip6af_down;
91 struct ip6asfrag *ip6af_up;
93 int ip6af_offset; /* offset in ip6af_m to next header */
94 int ip6af_frglen; /* fragmentable part length */
95 int ip6af_off; /* fragment offset */
96 u_int16_t ip6af_mff; /* more fragment bit in frag off */
99 #define IP6_REASS_MBUF(ip6af) (*(struct mbuf **)&((ip6af)->ip6af_m))
101 static MALLOC_DEFINE(M_FRAG6, "frag6", "IPv6 fragment reassembly header");
103 /* System wide (global) maximum and count of packets in reassembly queues. */
104 static int ip6_maxfrags;
105 static volatile u_int frag6_nfrags = 0;
107 /* Maximum and current packets in per-VNET reassembly queue. */
108 VNET_DEFINE_STATIC(int, ip6_maxfragpackets);
109 VNET_DEFINE_STATIC(volatile u_int, frag6_nfragpackets);
110 #define V_ip6_maxfragpackets VNET(ip6_maxfragpackets)
111 #define V_frag6_nfragpackets VNET(frag6_nfragpackets)
113 /* Maximum per-VNET reassembly queues per bucket and fragments per packet. */
114 VNET_DEFINE_STATIC(int, ip6_maxfragbucketsize);
115 VNET_DEFINE_STATIC(int, ip6_maxfragsperpacket);
116 #define V_ip6_maxfragbucketsize VNET(ip6_maxfragbucketsize)
117 #define V_ip6_maxfragsperpacket VNET(ip6_maxfragsperpacket)
119 /* Per-VNET reassembly queue buckets. */
120 VNET_DEFINE_STATIC(struct ip6qbucket, ip6qb[IP6REASS_NHASH]);
121 VNET_DEFINE_STATIC(uint32_t, ip6qb_hashseed);
122 #define V_ip6qb VNET(ip6qb)
123 #define V_ip6qb_hashseed VNET(ip6qb_hashseed)
125 #define IP6QB_LOCK(_b) mtx_lock(&V_ip6qb[(_b)].lock)
126 #define IP6QB_TRYLOCK(_b) mtx_trylock(&V_ip6qb[(_b)].lock)
127 #define IP6QB_LOCK_ASSERT(_b) mtx_assert(&V_ip6qb[(_b)].lock, MA_OWNED)
128 #define IP6QB_UNLOCK(_b) mtx_unlock(&V_ip6qb[(_b)].lock)
129 #define IP6QB_HEAD(_b) (&V_ip6qb[(_b)].ip6q)
132 * By default, limit the number of IP6 fragments across all reassembly
133 * queues to 1/32 of the total number of mbuf clusters.
135 * Limit the total number of reassembly queues per VNET to the
136 * IP6 fragment limit, but ensure the limit will not allow any bucket
137 * to grow above 100 items. (The bucket limit is
138 * IP_MAXFRAGPACKETS / (IPREASS_NHASH / 2), so the 50 is the correct
139 * multiplier to reach a 100-item limit.)
140 * The 100-item limit was chosen as brief testing seems to show that
141 * this produces "reasonable" performance on some subset of systems
144 #define IP6_MAXFRAGS (nmbclusters / 32)
145 #define IP6_MAXFRAGPACKETS (imin(IP6_MAXFRAGS, IP6REASS_NHASH * 50))
149 * Sysctls and helper function.
151 SYSCTL_DECL(_net_inet6_ip6);
154 frag6_set_bucketsize(void)
158 if ((i = V_ip6_maxfragpackets) > 0)
159 V_ip6_maxfragbucketsize = imax(i / (IP6REASS_NHASH / 2), 1);
162 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_MAXFRAGS, maxfrags,
163 CTLFLAG_RW, &ip6_maxfrags, 0,
164 "Maximum allowed number of outstanding IPv6 packet fragments. "
165 "A value of 0 means no fragmented packets will be accepted, while a "
166 "a value of -1 means no limit");
169 sysctl_ip6_maxfragpackets(SYSCTL_HANDLER_ARGS)
173 val = V_ip6_maxfragpackets;
174 error = sysctl_handle_int(oidp, &val, 0, req);
175 if (error != 0 || !req->newptr)
177 V_ip6_maxfragpackets = val;
178 frag6_set_bucketsize();
181 SYSCTL_PROC(_net_inet6_ip6, IPV6CTL_MAXFRAGPACKETS, maxfragpackets,
182 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
183 sysctl_ip6_maxfragpackets, "I",
184 "Default maximum number of outstanding fragmented IPv6 packets. "
185 "A value of 0 means no fragmented packets will be accepted, while a "
186 "a value of -1 means no limit");
187 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_MAXFRAGSPERPACKET, maxfragsperpacket,
188 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_maxfragsperpacket), 0,
189 "Maximum allowed number of fragments per packet");
190 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_MAXFRAGBUCKETSIZE, maxfragbucketsize,
191 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_maxfragbucketsize), 0,
192 "Maximum number of reassembly queues per hash bucket");
196 * Remove the IPv6 fragmentation header from the mbuf.
199 ip6_deletefraghdr(struct mbuf *m, int offset, int wait)
204 /* Delete frag6 header. */
205 if (m->m_len >= offset + sizeof(struct ip6_frag)) {
207 /* This is the only possible case with !PULLDOWN_TEST. */
208 ip6 = mtod(m, struct ip6_hdr *);
209 bcopy(ip6, (char *)ip6 + sizeof(struct ip6_frag),
211 m->m_data += sizeof(struct ip6_frag);
212 m->m_len -= sizeof(struct ip6_frag);
215 /* This comes with no copy if the boundary is on cluster. */
216 if ((t = m_split(m, offset, wait)) == NULL)
218 m_adj(t, sizeof(struct ip6_frag));
222 m->m_flags |= M_FRAGMENTED;
227 * Free a fragment reassembly header and all associated datagrams.
230 frag6_freef(struct ip6q *q6, uint32_t bucket)
233 struct ip6asfrag *af6, *down6;
236 IP6QB_LOCK_ASSERT(bucket);
238 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
241 m = IP6_REASS_MBUF(af6);
242 down6 = af6->ip6af_down;
243 frag6_deq(af6, bucket);
246 * Return ICMP time exceeded error for the 1st fragment.
247 * Just free other fragments.
249 if (af6->ip6af_off == 0 && m->m_pkthdr.rcvif != NULL) {
251 /* Adjust pointer. */
252 ip6 = mtod(m, struct ip6_hdr *);
254 /* Restore source and destination addresses. */
255 ip6->ip6_src = q6->ip6q_src;
256 ip6->ip6_dst = q6->ip6q_dst;
258 icmp6_error(m, ICMP6_TIME_EXCEEDED,
259 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
265 frag6_remque(q6, bucket);
266 atomic_subtract_int(&frag6_nfrags, q6->ip6q_nfrag);
268 mac_ip6q_destroy(q6);
271 atomic_subtract_int(&V_frag6_nfragpackets, 1);
275 * Drain off all datagram fragments belonging to
276 * the given network interface.
279 frag6_cleanup(void *arg __unused, struct ifnet *ifp)
281 struct ip6q *q6, *q6n, *head;
282 struct ip6asfrag *af6;
286 KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__));
288 CURVNET_SET_QUIET(ifp->if_vnet);
289 for (i = 0; i < IP6REASS_NHASH; i++) {
291 head = IP6QB_HEAD(i);
292 /* Scan fragment list. */
293 for (q6 = head->ip6q_next; q6 != head; q6 = q6n) {
296 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
297 af6 = af6->ip6af_down) {
298 m = IP6_REASS_MBUF(af6);
300 /* clear no longer valid rcvif pointer */
301 if (m->m_pkthdr.rcvif == ifp)
302 m->m_pkthdr.rcvif = NULL;
309 EVENTHANDLER_DEFINE(ifnet_departure_event, frag6_cleanup, NULL, 0);
312 * Like in RFC2460, in RFC8200, fragment and reassembly rules do not agree with
313 * each other, in terms of next header field handling in fragment header.
314 * While the sender will use the same value for all of the fragmented packets,
315 * receiver is suggested not to check for consistency.
317 * Fragment rules (p18,p19):
318 * (2) A Fragment header containing:
319 * The Next Header value that identifies the first header
320 * after the Per-Fragment headers of the original packet.
321 * -> next header field is same for all fragments
323 * Reassembly rule (p20):
324 * The Next Header field of the last header of the Per-Fragment
325 * headers is obtained from the Next Header field of the first
326 * fragment's Fragment header.
327 * -> should grab it from the first fragment only
329 * The following note also contradicts with fragment rule - no one is going to
330 * send different fragment with different next header field.
332 * Additional note (p22) [not an error]:
333 * The Next Header values in the Fragment headers of different
334 * fragments of the same original packet may differ. Only the value
335 * from the Offset zero fragment packet is used for reassembly.
336 * -> should grab it from the first fragment only
338 * There is no explicit reason given in the RFC. Historical reason maybe?
344 frag6_input(struct mbuf **mp, int *offp, int proto)
346 struct ifnet *dstifp;
347 struct ifnet *srcifp;
348 struct in6_ifaddr *ia6;
350 struct ip6_frag *ip6f;
351 struct ip6q *head, *q6;
352 struct ip6asfrag *af6, *af6dwn, *ip6af;
354 uint32_t hashkey[(sizeof(struct in6_addr) * 2 +
355 sizeof(ip6f->ip6f_ident)) / sizeof(uint32_t)];
356 uint32_t bucket, *hashkeyp;
357 int fragoff, frgpartlen; /* Must be larger than uint16_t. */
358 int nxt, offset, plen;
362 struct ip6_direct_ctx *ip6dc;
369 ip6 = mtod(m, struct ip6_hdr *);
370 #ifndef PULLDOWN_TEST
371 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
372 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
374 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
376 return (IPPROTO_DONE);
380 * Store receive network interface pointer for later.
382 srcifp = m->m_pkthdr.rcvif;
385 /* Find the destination interface of the packet. */
386 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
388 dstifp = ia6->ia_ifp;
389 ifa_free(&ia6->ia_ifa);
392 /* Jumbo payload cannot contain a fragment header. */
393 if (ip6->ip6_plen == 0) {
394 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
395 in6_ifstat_inc(dstifp, ifs6_reass_fail);
396 return (IPPROTO_DONE);
400 * Check whether fragment packet's fragment length is a
401 * multiple of 8 octets (unless it is the last one).
402 * sizeof(struct ip6_frag) == 8
403 * sizeof(struct ip6_hdr) = 40
405 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
406 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
407 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
408 offsetof(struct ip6_hdr, ip6_plen));
409 in6_ifstat_inc(dstifp, ifs6_reass_fail);
410 return (IPPROTO_DONE);
413 IP6STAT_INC(ip6s_fragments);
414 in6_ifstat_inc(dstifp, ifs6_reass_reqd);
416 /* Offset now points to data portion. */
417 offset += sizeof(struct ip6_frag);
420 * Handle "atomic" fragments (offset and m bit set to 0) upfront,
421 * unrelated to any reassembly. Still need to remove the frag hdr.
422 * See RFC 6946 and section 4.5 of RFC 8200.
424 if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) {
425 IP6STAT_INC(ip6s_atomicfrags);
426 /* XXX-BZ handle correctly. */
427 in6_ifstat_inc(dstifp, ifs6_reass_ok);
429 m->m_flags |= M_FRAGMENTED;
430 return (ip6f->ip6f_nxt);
433 /* Get fragment length and discard 0-byte fragments. */
434 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
435 if (frgpartlen == 0) {
436 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
437 offsetof(struct ip6_hdr, ip6_plen));
438 in6_ifstat_inc(dstifp, ifs6_reass_fail);
439 IP6STAT_INC(ip6s_fragdropped);
440 return (IPPROTO_DONE);
443 /* Generate a hash value for fragment bucket selection. */
445 memcpy(hashkeyp, &ip6->ip6_src, sizeof(struct in6_addr));
446 hashkeyp += sizeof(struct in6_addr) / sizeof(*hashkeyp);
447 memcpy(hashkeyp, &ip6->ip6_dst, sizeof(struct in6_addr));
448 hashkeyp += sizeof(struct in6_addr) / sizeof(*hashkeyp);
449 *hashkeyp = ip6f->ip6f_ident;
450 bucket = jenkins_hash32(hashkey, nitems(hashkey), V_ip6qb_hashseed);
451 bucket &= IP6REASS_HMASK;
452 head = IP6QB_HEAD(bucket);
456 * Enforce upper bound on number of fragments for the entire system.
457 * If maxfrag is 0, never accept fragments.
458 * If maxfrag is -1, accept all fragments without limitation.
460 if (ip6_maxfrags < 0)
462 else if (atomic_load_int(&frag6_nfrags) >= (u_int)ip6_maxfrags)
465 for (q6 = head->ip6q_next; q6 != head; q6 = q6->ip6q_next)
466 if (ip6f->ip6f_ident == q6->ip6q_ident &&
467 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
468 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)
470 && mac_ip6q_match(m, q6)
478 /* A first fragment to arrive creates a reassembly queue. */
482 * Enforce upper bound on number of fragmented packets
483 * for which we attempt reassembly;
484 * If maxfragpackets is 0, never accept fragments.
485 * If maxfragpackets is -1, accept all fragments without
488 if (V_ip6_maxfragpackets < 0)
490 else if (V_ip6qb[bucket].count >= V_ip6_maxfragbucketsize ||
491 atomic_load_int(&V_frag6_nfragpackets) >=
492 (u_int)V_ip6_maxfragpackets)
494 atomic_add_int(&V_frag6_nfragpackets, 1);
496 /* Allocate IPv6 fragement packet queue entry. */
497 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FRAG6,
502 if (mac_ip6q_init(q6, M_NOWAIT) != 0) {
506 mac_ip6q_create(m, q6);
508 frag6_insque_head(q6, head, bucket);
510 /* ip6q_nxt will be filled afterwards, from 1st fragment. */
511 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
513 q6->ip6q_nxtp = (u_char *)nxtp;
515 q6->ip6q_ident = ip6f->ip6f_ident;
516 q6->ip6q_ttl = IPV6_FRAGTTL;
517 q6->ip6q_src = ip6->ip6_src;
518 q6->ip6q_dst = ip6->ip6_dst;
520 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
521 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
527 * If it is the 1st fragment, record the length of the
528 * unfragmentable part and the next header of the fragment header.
530 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
532 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
533 sizeof(struct ip6_frag);
534 q6->ip6q_nxt = ip6f->ip6f_nxt;
538 * Check that the reassembled packet would not exceed 65535 bytes
540 * If it would exceed, discard the fragment and return an ICMP error.
542 if (q6->ip6q_unfrglen >= 0) {
543 /* The 1st fragment has already arrived. */
544 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
545 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
546 offset - sizeof(struct ip6_frag) +
547 offsetof(struct ip6_frag, ip6f_offlg));
548 IP6QB_UNLOCK(bucket);
549 return (IPPROTO_DONE);
551 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
552 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
553 offset - sizeof(struct ip6_frag) +
554 offsetof(struct ip6_frag, ip6f_offlg));
555 IP6QB_UNLOCK(bucket);
556 return (IPPROTO_DONE);
559 * If it is the first fragment, do the above check for each
560 * fragment already stored in the reassembly queue.
563 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
565 af6dwn = af6->ip6af_down;
567 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
569 struct ip6_hdr *ip6err;
573 merr = IP6_REASS_MBUF(af6);
574 erroff = af6->ip6af_offset;
576 /* Dequeue the fragment. */
577 frag6_deq(af6, bucket);
580 /* Set a valid receive interface pointer. */
581 merr->m_pkthdr.rcvif = srcifp;
583 /* Adjust pointer. */
584 ip6err = mtod(merr, struct ip6_hdr *);
587 * Restore source and destination addresses
588 * in the erroneous IPv6 header.
590 ip6err->ip6_src = q6->ip6q_src;
591 ip6err->ip6_dst = q6->ip6q_dst;
593 icmp6_error(merr, ICMP6_PARAM_PROB,
594 ICMP6_PARAMPROB_HEADER,
595 erroff - sizeof(struct ip6_frag) +
596 offsetof(struct ip6_frag, ip6f_offlg));
601 /* Allocate an IPv6 fragement queue entry for this fragmented part. */
602 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FRAG6,
606 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
607 ip6af->ip6af_off = fragoff;
608 ip6af->ip6af_frglen = frgpartlen;
609 ip6af->ip6af_offset = offset;
610 IP6_REASS_MBUF(ip6af) = m;
613 af6 = (struct ip6asfrag *)q6;
617 /* Do duplicate, condition, and boundry checks. */
619 * Handle ECN by comparing this segment with the first one;
620 * if CE is set, do not lose CE.
621 * Drop if CE and not-ECT are mixed for the same packet.
623 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
625 if (ecn == IPTOS_ECN_CE) {
626 if (ecn0 == IPTOS_ECN_NOTECT) {
627 free(ip6af, M_FRAG6);
630 if (ecn0 != IPTOS_ECN_CE)
631 q6->ip6q_ecn = IPTOS_ECN_CE;
633 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) {
634 free(ip6af, M_FRAG6);
638 /* Find a fragmented part which begins after this one does. */
639 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
640 af6 = af6->ip6af_down)
641 if (af6->ip6af_off > ip6af->ip6af_off)
645 * If the incoming framgent overlaps some existing fragments in
646 * the reassembly queue, drop both the new fragment and the
647 * entire reassembly queue. However, if the new fragment
648 * is an exact duplicate of an existing fragment, only silently
649 * drop the existing fragment and leave the fragmentation queue
650 * unchanged, as allowed by the RFC. (RFC 8200, 4.5)
652 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
653 if (af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen -
654 ip6af->ip6af_off > 0) {
655 free(ip6af, M_FRAG6);
659 if (af6 != (struct ip6asfrag *)q6) {
660 if (ip6af->ip6af_off + ip6af->ip6af_frglen -
661 af6->ip6af_off > 0) {
662 free(ip6af, M_FRAG6);
670 mac_ip6q_update(m, q6);
674 * Stick new segment in its place; check for complete reassembly.
675 * If not complete, check fragment limit. Move to front of packet
676 * queue, as we are the most recently active fragmented packet.
678 frag6_enq(ip6af, af6->ip6af_up, bucket);
679 atomic_add_int(&frag6_nfrags, 1);
682 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
683 af6 = af6->ip6af_down) {
684 if (af6->ip6af_off != plen) {
685 if (q6->ip6q_nfrag > V_ip6_maxfragsperpacket) {
686 IP6STAT_ADD(ip6s_fragdropped, q6->ip6q_nfrag);
687 frag6_freef(q6, bucket);
689 IP6QB_UNLOCK(bucket);
690 return (IPPROTO_DONE);
692 plen += af6->ip6af_frglen;
694 if (af6->ip6af_up->ip6af_mff) {
695 if (q6->ip6q_nfrag > V_ip6_maxfragsperpacket) {
696 IP6STAT_ADD(ip6s_fragdropped, q6->ip6q_nfrag);
697 frag6_freef(q6, bucket);
699 IP6QB_UNLOCK(bucket);
700 return (IPPROTO_DONE);
703 /* Reassembly is complete; concatenate fragments. */
704 ip6af = q6->ip6q_down;
705 t = m = IP6_REASS_MBUF(ip6af);
706 af6 = ip6af->ip6af_down;
707 frag6_deq(ip6af, bucket);
708 while (af6 != (struct ip6asfrag *)q6) {
709 m->m_pkthdr.csum_flags &=
710 IP6_REASS_MBUF(af6)->m_pkthdr.csum_flags;
711 m->m_pkthdr.csum_data +=
712 IP6_REASS_MBUF(af6)->m_pkthdr.csum_data;
714 af6dwn = af6->ip6af_down;
715 frag6_deq(af6, bucket);
718 m_adj(IP6_REASS_MBUF(af6), af6->ip6af_offset);
719 m_demote_pkthdr(IP6_REASS_MBUF(af6));
720 m_cat(t, IP6_REASS_MBUF(af6));
725 while (m->m_pkthdr.csum_data & 0xffff0000)
726 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) +
727 (m->m_pkthdr.csum_data >> 16);
729 /* Adjust offset to point where the original next header starts. */
730 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
731 free(ip6af, M_FRAG6);
732 ip6 = mtod(m, struct ip6_hdr *);
733 ip6->ip6_plen = htons((u_short)plen + offset - sizeof(struct ip6_hdr));
734 if (q6->ip6q_ecn == IPTOS_ECN_CE)
735 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20);
738 if (ip6_deletefraghdr(m, offset, M_NOWAIT) != 0) {
739 frag6_remque(q6, bucket);
740 atomic_subtract_int(&frag6_nfrags, q6->ip6q_nfrag);
742 mac_ip6q_destroy(q6);
745 atomic_subtract_int(&V_frag6_nfragpackets, 1);
750 /* Set nxt(-hdr field value) to the original value. */
751 m_copyback(m, ip6_get_prevhdr(m, offset), sizeof(uint8_t),
754 frag6_remque(q6, bucket);
755 atomic_subtract_int(&frag6_nfrags, q6->ip6q_nfrag);
757 mac_ip6q_reassemble(q6, m);
758 mac_ip6q_destroy(q6);
761 atomic_subtract_int(&V_frag6_nfragpackets, 1);
763 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
766 for (t = m; t; t = t->m_next)
768 m->m_pkthdr.len = plen;
769 /* Set a valid receive interface pointer. */
770 m->m_pkthdr.rcvif = srcifp;
774 mtag = m_tag_alloc(MTAG_ABI_IPV6, IPV6_TAG_DIRECT, sizeof(*ip6dc),
779 ip6dc = (struct ip6_direct_ctx *)(mtag + 1);
780 ip6dc->ip6dc_nxt = nxt;
781 ip6dc->ip6dc_off = offset;
783 m_tag_prepend(m, mtag);
786 IP6QB_UNLOCK(bucket);
787 IP6STAT_INC(ip6s_reassembled);
788 in6_ifstat_inc(dstifp, ifs6_reass_ok);
791 /* Queue/dispatch for reprocessing. */
792 netisr_dispatch(NETISR_IPV6_DIRECT, m);
793 return (IPPROTO_DONE);
796 /* Tell launch routine the next header. */
803 IP6QB_UNLOCK(bucket);
804 in6_ifstat_inc(dstifp, ifs6_reass_fail);
805 IP6STAT_INC(ip6s_fragdropped);
807 return (IPPROTO_DONE);
811 * IPv6 reassembling timer processing;
812 * if a timer expires on a reassembly queue, discard it.
817 VNET_ITERATOR_DECL(vnet_iter);
818 struct ip6q *head, *q6;
821 VNET_LIST_RLOCK_NOSLEEP();
822 VNET_FOREACH(vnet_iter) {
823 CURVNET_SET(vnet_iter);
824 for (bucket = 0; bucket < IP6REASS_NHASH; bucket++) {
826 head = IP6QB_HEAD(bucket);
827 q6 = head->ip6q_next;
830 * XXXJTL: This should never happen. This
831 * should turn into an assertion.
833 IP6QB_UNLOCK(bucket);
839 if (q6->ip6q_prev->ip6q_ttl == 0) {
840 IP6STAT_ADD(ip6s_fragtimeout,
841 q6->ip6q_prev->ip6q_nfrag);
842 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
843 frag6_freef(q6->ip6q_prev, bucket);
847 * If we are over the maximum number of fragments
848 * (due to the limit being lowered), drain off
849 * enough to get down to the new limit.
850 * Note that we drain all reassembly queues if
851 * maxfragpackets is 0 (fragmentation is disabled),
852 * and do not enforce a limit when maxfragpackets
855 while ((V_ip6_maxfragpackets == 0 ||
856 (V_ip6_maxfragpackets > 0 &&
857 V_ip6qb[bucket].count > V_ip6_maxfragbucketsize)) &&
858 head->ip6q_prev != head) {
859 IP6STAT_ADD(ip6s_fragoverflow,
860 q6->ip6q_prev->ip6q_nfrag);
861 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
862 frag6_freef(head->ip6q_prev, bucket);
864 IP6QB_UNLOCK(bucket);
867 * If we are still over the maximum number of fragmented
868 * packets, drain off enough to get down to the new limit.
871 while (V_ip6_maxfragpackets >= 0 &&
872 atomic_load_int(&V_frag6_nfragpackets) >
873 (u_int)V_ip6_maxfragpackets) {
875 head = IP6QB_HEAD(bucket);
876 if (head->ip6q_prev != head) {
877 IP6STAT_ADD(ip6s_fragoverflow,
878 q6->ip6q_prev->ip6q_nfrag);
879 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
880 frag6_freef(head->ip6q_prev, bucket);
882 IP6QB_UNLOCK(bucket);
883 bucket = (bucket + 1) % IP6REASS_NHASH;
887 VNET_LIST_RUNLOCK_NOSLEEP();
891 * Eventhandler to adjust limits in case nmbclusters change.
894 frag6_change(void *tag)
896 VNET_ITERATOR_DECL(vnet_iter);
898 ip6_maxfrags = IP6_MAXFRAGS;
899 VNET_LIST_RLOCK_NOSLEEP();
900 VNET_FOREACH(vnet_iter) {
901 CURVNET_SET(vnet_iter);
902 V_ip6_maxfragpackets = IP6_MAXFRAGPACKETS;
903 frag6_set_bucketsize();
906 VNET_LIST_RUNLOCK_NOSLEEP();
910 * Initialise reassembly queue and fragment identifier.
918 V_ip6_maxfragpackets = IP6_MAXFRAGPACKETS;
919 frag6_set_bucketsize();
920 for (bucket = 0; bucket < IP6REASS_NHASH; bucket++) {
921 q6 = IP6QB_HEAD(bucket);
922 q6->ip6q_next = q6->ip6q_prev = q6;
923 mtx_init(&V_ip6qb[bucket].lock, "ip6qlock", NULL, MTX_DEF);
924 V_ip6qb[bucket].count = 0;
926 V_ip6qb_hashseed = arc4random();
927 V_ip6_maxfragsperpacket = 64;
928 if (!IS_DEFAULT_VNET(curvnet))
931 ip6_maxfrags = IP6_MAXFRAGS;
932 EVENTHANDLER_REGISTER(nmbclusters_change,
933 frag6_change, NULL, EVENTHANDLER_PRI_ANY);
937 * Drain off all datagram fragments.
942 VNET_ITERATOR_DECL(vnet_iter);
946 VNET_LIST_RLOCK_NOSLEEP();
947 VNET_FOREACH(vnet_iter) {
948 CURVNET_SET(vnet_iter);
949 for (bucket = 0; bucket < IP6REASS_NHASH; bucket++) {
950 if (IP6QB_TRYLOCK(bucket) == 0)
952 head = IP6QB_HEAD(bucket);
953 while (head->ip6q_next != head) {
954 IP6STAT_INC(ip6s_fragdropped);
955 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
956 frag6_freef(head->ip6q_next, bucket);
958 IP6QB_UNLOCK(bucket);
962 VNET_LIST_RUNLOCK_NOSLEEP();
966 * Put an ip fragment on a reassembly chain.
967 * Like insque, but pointers in middle of structure.
970 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6,
971 uint32_t bucket __unused)
974 IP6QB_LOCK_ASSERT(bucket);
977 af6->ip6af_down = up6->ip6af_down;
978 up6->ip6af_down->ip6af_up = af6;
979 up6->ip6af_down = af6;
983 * To frag6_enq as remque is to insque.
986 frag6_deq(struct ip6asfrag *af6, uint32_t bucket __unused)
989 IP6QB_LOCK_ASSERT(bucket);
991 af6->ip6af_up->ip6af_down = af6->ip6af_down;
992 af6->ip6af_down->ip6af_up = af6->ip6af_up;
996 frag6_insque_head(struct ip6q *new, struct ip6q *old, uint32_t bucket)
999 IP6QB_LOCK_ASSERT(bucket);
1000 KASSERT(IP6QB_HEAD(bucket) == old,
1001 ("%s: attempt to insert at head of wrong bucket"
1002 " (bucket=%u, old=%p)", __func__, bucket, old));
1004 new->ip6q_prev = old;
1005 new->ip6q_next = old->ip6q_next;
1006 old->ip6q_next->ip6q_prev= new;
1007 old->ip6q_next = new;
1008 V_ip6qb[bucket].count++;
1012 frag6_remque(struct ip6q *p6, uint32_t bucket)
1015 IP6QB_LOCK_ASSERT(bucket);
1017 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
1018 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
1019 V_ip6qb[bucket].count--;