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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IPv6 fragment reassembly
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on: net/ipv4/ip_fragment.c
10 */
11
12/*
13 * Fixes:
14 * Andi Kleen Make it work with multiple hosts.
15 * More RFC compliance.
16 *
17 * Horst von Brand Add missing #include <linux/string.h>
18 * Alexey Kuznetsov SMP races, threading, cleanup.
19 * Patrick McHardy LRU queue of frag heads for evictor.
20 * Mitsuru KANDA @USAGI Register inet6_protocol{}.
21 * David Stevens and
22 * YOSHIFUJI,H. @USAGI Always remove fragment header to
23 * calculate ICV correctly.
24 */
25
26#define pr_fmt(fmt) "IPv6: " fmt
27
28#include <linux/errno.h>
29#include <linux/types.h>
30#include <linux/string.h>
31#include <linux/socket.h>
32#include <linux/sockios.h>
33#include <linux/jiffies.h>
34#include <linux/net.h>
35#include <linux/list.h>
36#include <linux/netdevice.h>
37#include <linux/in6.h>
38#include <linux/ipv6.h>
39#include <linux/icmpv6.h>
40#include <linux/random.h>
41#include <linux/jhash.h>
42#include <linux/skbuff.h>
43#include <linux/slab.h>
44#include <linux/export.h>
45#include <linux/tcp.h>
46#include <linux/udp.h>
47
48#include <net/sock.h>
49#include <net/snmp.h>
50
51#include <net/ipv6.h>
52#include <net/ip6_route.h>
53#include <net/protocol.h>
54#include <net/transp_v6.h>
55#include <net/rawv6.h>
56#include <net/ndisc.h>
57#include <net/addrconf.h>
58#include <net/ipv6_frag.h>
59#include <net/inet_ecn.h>
60
61static const char ip6_frag_cache_name[] = "ip6-frags";
62
63static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
64{
65 return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
66}
67
68static struct inet_frags ip6_frags;
69
70static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
71 struct sk_buff *prev_tail, struct net_device *dev);
72
73static void ip6_frag_expire(struct timer_list *t)
74{
75 struct inet_frag_queue *frag = from_timer(frag, t, timer);
76 struct frag_queue *fq;
77
78 fq = container_of(frag, struct frag_queue, q);
79
80 ip6frag_expire_frag_queue(fq->q.fqdir->net, fq);
81}
82
83static struct frag_queue *
84fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif)
85{
86 struct frag_v6_compare_key key = {
87 .id = id,
88 .saddr = hdr->saddr,
89 .daddr = hdr->daddr,
90 .user = IP6_DEFRAG_LOCAL_DELIVER,
91 .iif = iif,
92 };
93 struct inet_frag_queue *q;
94
95 if (!(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_MULTICAST |
96 IPV6_ADDR_LINKLOCAL)))
97 key.iif = 0;
98
99 q = inet_frag_find(net->ipv6.fqdir, &key);
100 if (!q)
101 return NULL;
102
103 return container_of(q, struct frag_queue, q);
104}
105
106static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
107 struct frag_hdr *fhdr, int nhoff,
108 u32 *prob_offset)
109{
110 struct net *net = dev_net(skb_dst(skb)->dev);
111 int offset, end, fragsize;
112 struct sk_buff *prev_tail;
113 struct net_device *dev;
114 int err = -ENOENT;
115 u8 ecn;
116
117 if (fq->q.flags & INET_FRAG_COMPLETE)
118 goto err;
119
120 err = -EINVAL;
121 offset = ntohs(fhdr->frag_off) & ~0x7;
122 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
123 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
124
125 if ((unsigned int)end > IPV6_MAXPLEN) {
126 *prob_offset = (u8 *)&fhdr->frag_off - skb_network_header(skb);
127 /* note that if prob_offset is set, the skb is freed elsewhere,
128 * we do not free it here.
129 */
130 return -1;
131 }
132
133 ecn = ip6_frag_ecn(ipv6_hdr(skb));
134
135 if (skb->ip_summed == CHECKSUM_COMPLETE) {
136 const unsigned char *nh = skb_network_header(skb);
137 skb->csum = csum_sub(skb->csum,
138 csum_partial(nh, (u8 *)(fhdr + 1) - nh,
139 0));
140 }
141
142 /* Is this the final fragment? */
143 if (!(fhdr->frag_off & htons(IP6_MF))) {
144 /* If we already have some bits beyond end
145 * or have different end, the segment is corrupted.
146 */
147 if (end < fq->q.len ||
148 ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
149 goto discard_fq;
150 fq->q.flags |= INET_FRAG_LAST_IN;
151 fq->q.len = end;
152 } else {
153 /* Check if the fragment is rounded to 8 bytes.
154 * Required by the RFC.
155 */
156 if (end & 0x7) {
157 /* RFC2460 says always send parameter problem in
158 * this case. -DaveM
159 */
160 *prob_offset = offsetof(struct ipv6hdr, payload_len);
161 return -1;
162 }
163 if (end > fq->q.len) {
164 /* Some bits beyond end -> corruption. */
165 if (fq->q.flags & INET_FRAG_LAST_IN)
166 goto discard_fq;
167 fq->q.len = end;
168 }
169 }
170
171 if (end == offset)
172 goto discard_fq;
173
174 err = -ENOMEM;
175 /* Point into the IP datagram 'data' part. */
176 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
177 goto discard_fq;
178
179 err = pskb_trim_rcsum(skb, end - offset);
180 if (err)
181 goto discard_fq;
182
183 /* Note : skb->rbnode and skb->dev share the same location. */
184 dev = skb->dev;
185 /* Makes sure compiler wont do silly aliasing games */
186 barrier();
187
188 prev_tail = fq->q.fragments_tail;
189 err = inet_frag_queue_insert(&fq->q, skb, offset, end);
190 if (err)
191 goto insert_error;
192
193 if (dev)
194 fq->iif = dev->ifindex;
195
196 fq->q.stamp = skb->tstamp;
197 fq->q.meat += skb->len;
198 fq->ecn |= ecn;
199 add_frag_mem_limit(fq->q.fqdir, skb->truesize);
200
201 fragsize = -skb_network_offset(skb) + skb->len;
202 if (fragsize > fq->q.max_size)
203 fq->q.max_size = fragsize;
204
205 /* The first fragment.
206 * nhoffset is obtained from the first fragment, of course.
207 */
208 if (offset == 0) {
209 fq->nhoffset = nhoff;
210 fq->q.flags |= INET_FRAG_FIRST_IN;
211 }
212
213 if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
214 fq->q.meat == fq->q.len) {
215 unsigned long orefdst = skb->_skb_refdst;
216
217 skb->_skb_refdst = 0UL;
218 err = ip6_frag_reasm(fq, skb, prev_tail, dev);
219 skb->_skb_refdst = orefdst;
220 return err;
221 }
222
223 skb_dst_drop(skb);
224 return -EINPROGRESS;
225
226insert_error:
227 if (err == IPFRAG_DUP) {
228 kfree_skb(skb);
229 return -EINVAL;
230 }
231 err = -EINVAL;
232 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
233 IPSTATS_MIB_REASM_OVERLAPS);
234discard_fq:
235 inet_frag_kill(&fq->q);
236 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
237 IPSTATS_MIB_REASMFAILS);
238err:
239 kfree_skb(skb);
240 return err;
241}
242
243/*
244 * Check if this packet is complete.
245 *
246 * It is called with locked fq, and caller must check that
247 * queue is eligible for reassembly i.e. it is not COMPLETE,
248 * the last and the first frames arrived and all the bits are here.
249 */
250static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
251 struct sk_buff *prev_tail, struct net_device *dev)
252{
253 struct net *net = fq->q.fqdir->net;
254 unsigned int nhoff;
255 void *reasm_data;
256 int payload_len;
257 u8 ecn;
258
259 inet_frag_kill(&fq->q);
260
261 ecn = ip_frag_ecn_table[fq->ecn];
262 if (unlikely(ecn == 0xff))
263 goto out_fail;
264
265 reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
266 if (!reasm_data)
267 goto out_oom;
268
269 payload_len = ((skb->data - skb_network_header(skb)) -
270 sizeof(struct ipv6hdr) + fq->q.len -
271 sizeof(struct frag_hdr));
272 if (payload_len > IPV6_MAXPLEN)
273 goto out_oversize;
274
275 /* We have to remove fragment header from datagram and to relocate
276 * header in order to calculate ICV correctly. */
277 nhoff = fq->nhoffset;
278 skb_network_header(skb)[nhoff] = skb_transport_header(skb)[0];
279 memmove(skb->head + sizeof(struct frag_hdr), skb->head,
280 (skb->data - skb->head) - sizeof(struct frag_hdr));
281 if (skb_mac_header_was_set(skb))
282 skb->mac_header += sizeof(struct frag_hdr);
283 skb->network_header += sizeof(struct frag_hdr);
284
285 skb_reset_transport_header(skb);
286
287 inet_frag_reasm_finish(&fq->q, skb, reasm_data, true);
288
289 skb->dev = dev;
290 ipv6_hdr(skb)->payload_len = htons(payload_len);
291 ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn);
292 IP6CB(skb)->nhoff = nhoff;
293 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
294 IP6CB(skb)->frag_max_size = fq->q.max_size;
295
296 /* Yes, and fold redundant checksum back. 8) */
297 skb_postpush_rcsum(skb, skb_network_header(skb),
298 skb_network_header_len(skb));
299
300 rcu_read_lock();
301 __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMOKS);
302 rcu_read_unlock();
303 fq->q.rb_fragments = RB_ROOT;
304 fq->q.fragments_tail = NULL;
305 fq->q.last_run_head = NULL;
306 return 1;
307
308out_oversize:
309 net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
310 goto out_fail;
311out_oom:
312 net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
313out_fail:
314 rcu_read_lock();
315 __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMFAILS);
316 rcu_read_unlock();
317 inet_frag_kill(&fq->q);
318 return -1;
319}
320
321static int ipv6_frag_rcv(struct sk_buff *skb)
322{
323 struct frag_hdr *fhdr;
324 struct frag_queue *fq;
325 const struct ipv6hdr *hdr = ipv6_hdr(skb);
326 struct net *net = dev_net(skb_dst(skb)->dev);
327 u8 nexthdr;
328 int iif;
329
330 if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
331 goto fail_hdr;
332
333 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
334
335 /* Jumbo payload inhibits frag. header */
336 if (hdr->payload_len == 0)
337 goto fail_hdr;
338
339 if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
340 sizeof(struct frag_hdr))))
341 goto fail_hdr;
342
343 hdr = ipv6_hdr(skb);
344 fhdr = (struct frag_hdr *)skb_transport_header(skb);
345
346 if (!(fhdr->frag_off & htons(IP6_OFFSET | IP6_MF))) {
347 /* It is not a fragmented frame */
348 skb->transport_header += sizeof(struct frag_hdr);
349 __IP6_INC_STATS(net,
350 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
351
352 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
353 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
354 IP6CB(skb)->frag_max_size = ntohs(hdr->payload_len) +
355 sizeof(struct ipv6hdr);
356 return 1;
357 }
358
359 /* RFC 8200, Section 4.5 Fragment Header:
360 * If the first fragment does not include all headers through an
361 * Upper-Layer header, then that fragment should be discarded and
362 * an ICMP Parameter Problem, Code 3, message should be sent to
363 * the source of the fragment, with the Pointer field set to zero.
364 */
365 nexthdr = hdr->nexthdr;
366 if (ipv6frag_thdr_truncated(skb, skb_transport_offset(skb), &nexthdr)) {
367 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
368 IPSTATS_MIB_INHDRERRORS);
369 icmpv6_param_prob(skb, ICMPV6_HDR_INCOMP, 0);
370 return -1;
371 }
372
373 iif = skb->dev ? skb->dev->ifindex : 0;
374 fq = fq_find(net, fhdr->identification, hdr, iif);
375 if (fq) {
376 u32 prob_offset = 0;
377 int ret;
378
379 spin_lock(&fq->q.lock);
380
381 fq->iif = iif;
382 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff,
383 &prob_offset);
384
385 spin_unlock(&fq->q.lock);
386 inet_frag_put(&fq->q);
387 if (prob_offset) {
388 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
389 IPSTATS_MIB_INHDRERRORS);
390 /* icmpv6_param_prob() calls kfree_skb(skb) */
391 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, prob_offset);
392 }
393 return ret;
394 }
395
396 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
397 kfree_skb(skb);
398 return -1;
399
400fail_hdr:
401 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
402 IPSTATS_MIB_INHDRERRORS);
403 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
404 return -1;
405}
406
407static const struct inet6_protocol frag_protocol = {
408 .handler = ipv6_frag_rcv,
409 .flags = INET6_PROTO_NOPOLICY,
410};
411
412#ifdef CONFIG_SYSCTL
413
414static struct ctl_table ip6_frags_ns_ctl_table[] = {
415 {
416 .procname = "ip6frag_high_thresh",
417 .maxlen = sizeof(unsigned long),
418 .mode = 0644,
419 .proc_handler = proc_doulongvec_minmax,
420 },
421 {
422 .procname = "ip6frag_low_thresh",
423 .maxlen = sizeof(unsigned long),
424 .mode = 0644,
425 .proc_handler = proc_doulongvec_minmax,
426 },
427 {
428 .procname = "ip6frag_time",
429 .maxlen = sizeof(int),
430 .mode = 0644,
431 .proc_handler = proc_dointvec_jiffies,
432 },
433 { }
434};
435
436/* secret interval has been deprecated */
437static int ip6_frags_secret_interval_unused;
438static struct ctl_table ip6_frags_ctl_table[] = {
439 {
440 .procname = "ip6frag_secret_interval",
441 .data = &ip6_frags_secret_interval_unused,
442 .maxlen = sizeof(int),
443 .mode = 0644,
444 .proc_handler = proc_dointvec_jiffies,
445 },
446 { }
447};
448
449static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
450{
451 struct ctl_table *table;
452 struct ctl_table_header *hdr;
453
454 table = ip6_frags_ns_ctl_table;
455 if (!net_eq(net, &init_net)) {
456 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
457 if (!table)
458 goto err_alloc;
459
460 }
461 table[0].data = &net->ipv6.fqdir->high_thresh;
462 table[0].extra1 = &net->ipv6.fqdir->low_thresh;
463 table[1].data = &net->ipv6.fqdir->low_thresh;
464 table[1].extra2 = &net->ipv6.fqdir->high_thresh;
465 table[2].data = &net->ipv6.fqdir->timeout;
466
467 hdr = register_net_sysctl(net, "net/ipv6", table);
468 if (!hdr)
469 goto err_reg;
470
471 net->ipv6.sysctl.frags_hdr = hdr;
472 return 0;
473
474err_reg:
475 if (!net_eq(net, &init_net))
476 kfree(table);
477err_alloc:
478 return -ENOMEM;
479}
480
481static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
482{
483 struct ctl_table *table;
484
485 table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
486 unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
487 if (!net_eq(net, &init_net))
488 kfree(table);
489}
490
491static struct ctl_table_header *ip6_ctl_header;
492
493static int ip6_frags_sysctl_register(void)
494{
495 ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
496 ip6_frags_ctl_table);
497 return ip6_ctl_header == NULL ? -ENOMEM : 0;
498}
499
500static void ip6_frags_sysctl_unregister(void)
501{
502 unregister_net_sysctl_table(ip6_ctl_header);
503}
504#else
505static int ip6_frags_ns_sysctl_register(struct net *net)
506{
507 return 0;
508}
509
510static void ip6_frags_ns_sysctl_unregister(struct net *net)
511{
512}
513
514static int ip6_frags_sysctl_register(void)
515{
516 return 0;
517}
518
519static void ip6_frags_sysctl_unregister(void)
520{
521}
522#endif
523
524static int __net_init ipv6_frags_init_net(struct net *net)
525{
526 int res;
527
528 res = fqdir_init(&net->ipv6.fqdir, &ip6_frags, net);
529 if (res < 0)
530 return res;
531
532 net->ipv6.fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
533 net->ipv6.fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
534 net->ipv6.fqdir->timeout = IPV6_FRAG_TIMEOUT;
535
536 res = ip6_frags_ns_sysctl_register(net);
537 if (res < 0)
538 fqdir_exit(net->ipv6.fqdir);
539 return res;
540}
541
542static void __net_exit ipv6_frags_pre_exit_net(struct net *net)
543{
544 fqdir_pre_exit(net->ipv6.fqdir);
545}
546
547static void __net_exit ipv6_frags_exit_net(struct net *net)
548{
549 ip6_frags_ns_sysctl_unregister(net);
550 fqdir_exit(net->ipv6.fqdir);
551}
552
553static struct pernet_operations ip6_frags_ops = {
554 .init = ipv6_frags_init_net,
555 .pre_exit = ipv6_frags_pre_exit_net,
556 .exit = ipv6_frags_exit_net,
557};
558
559static const struct rhashtable_params ip6_rhash_params = {
560 .head_offset = offsetof(struct inet_frag_queue, node),
561 .hashfn = ip6frag_key_hashfn,
562 .obj_hashfn = ip6frag_obj_hashfn,
563 .obj_cmpfn = ip6frag_obj_cmpfn,
564 .automatic_shrinking = true,
565};
566
567int __init ipv6_frag_init(void)
568{
569 int ret;
570
571 ip6_frags.constructor = ip6frag_init;
572 ip6_frags.destructor = NULL;
573 ip6_frags.qsize = sizeof(struct frag_queue);
574 ip6_frags.frag_expire = ip6_frag_expire;
575 ip6_frags.frags_cache_name = ip6_frag_cache_name;
576 ip6_frags.rhash_params = ip6_rhash_params;
577 ret = inet_frags_init(&ip6_frags);
578 if (ret)
579 goto out;
580
581 ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
582 if (ret)
583 goto err_protocol;
584
585 ret = ip6_frags_sysctl_register();
586 if (ret)
587 goto err_sysctl;
588
589 ret = register_pernet_subsys(&ip6_frags_ops);
590 if (ret)
591 goto err_pernet;
592
593out:
594 return ret;
595
596err_pernet:
597 ip6_frags_sysctl_unregister();
598err_sysctl:
599 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
600err_protocol:
601 inet_frags_fini(&ip6_frags);
602 goto out;
603}
604
605void ipv6_frag_exit(void)
606{
607 ip6_frags_sysctl_unregister();
608 unregister_pernet_subsys(&ip6_frags_ops);
609 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
610 inet_frags_fini(&ip6_frags);
611}
1/*
2 * IPv6 fragment reassembly
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on: net/ipv4/ip_fragment.c
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16/*
17 * Fixes:
18 * Andi Kleen Make it work with multiple hosts.
19 * More RFC compliance.
20 *
21 * Horst von Brand Add missing #include <linux/string.h>
22 * Alexey Kuznetsov SMP races, threading, cleanup.
23 * Patrick McHardy LRU queue of frag heads for evictor.
24 * Mitsuru KANDA @USAGI Register inet6_protocol{}.
25 * David Stevens and
26 * YOSHIFUJI,H. @USAGI Always remove fragment header to
27 * calculate ICV correctly.
28 */
29
30#define pr_fmt(fmt) "IPv6: " fmt
31
32#include <linux/errno.h>
33#include <linux/types.h>
34#include <linux/string.h>
35#include <linux/socket.h>
36#include <linux/sockios.h>
37#include <linux/jiffies.h>
38#include <linux/net.h>
39#include <linux/list.h>
40#include <linux/netdevice.h>
41#include <linux/in6.h>
42#include <linux/ipv6.h>
43#include <linux/icmpv6.h>
44#include <linux/random.h>
45#include <linux/jhash.h>
46#include <linux/skbuff.h>
47#include <linux/slab.h>
48#include <linux/export.h>
49
50#include <net/sock.h>
51#include <net/snmp.h>
52
53#include <net/ipv6.h>
54#include <net/ip6_route.h>
55#include <net/protocol.h>
56#include <net/transp_v6.h>
57#include <net/rawv6.h>
58#include <net/ndisc.h>
59#include <net/addrconf.h>
60#include <net/inet_frag.h>
61#include <net/inet_ecn.h>
62
63struct ip6frag_skb_cb
64{
65 struct inet6_skb_parm h;
66 int offset;
67};
68
69#define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb))
70
71static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
72{
73 return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
74}
75
76static struct inet_frags ip6_frags;
77
78static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
79 struct net_device *dev);
80
81/*
82 * callers should be careful not to use the hash value outside the ipfrag_lock
83 * as doing so could race with ipfrag_hash_rnd being recalculated.
84 */
85static unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
86 const struct in6_addr *daddr)
87{
88 u32 c;
89
90 net_get_random_once(&ip6_frags.rnd, sizeof(ip6_frags.rnd));
91 c = jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
92 (__force u32)id, ip6_frags.rnd);
93
94 return c & (INETFRAGS_HASHSZ - 1);
95}
96
97static unsigned int ip6_hashfn(struct inet_frag_queue *q)
98{
99 struct frag_queue *fq;
100
101 fq = container_of(q, struct frag_queue, q);
102 return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr);
103}
104
105bool ip6_frag_match(struct inet_frag_queue *q, void *a)
106{
107 struct frag_queue *fq;
108 struct ip6_create_arg *arg = a;
109
110 fq = container_of(q, struct frag_queue, q);
111 return fq->id == arg->id &&
112 fq->user == arg->user &&
113 ipv6_addr_equal(&fq->saddr, arg->src) &&
114 ipv6_addr_equal(&fq->daddr, arg->dst);
115}
116EXPORT_SYMBOL(ip6_frag_match);
117
118void ip6_frag_init(struct inet_frag_queue *q, void *a)
119{
120 struct frag_queue *fq = container_of(q, struct frag_queue, q);
121 struct ip6_create_arg *arg = a;
122
123 fq->id = arg->id;
124 fq->user = arg->user;
125 fq->saddr = *arg->src;
126 fq->daddr = *arg->dst;
127 fq->ecn = arg->ecn;
128}
129EXPORT_SYMBOL(ip6_frag_init);
130
131void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
132 struct inet_frags *frags)
133{
134 struct net_device *dev = NULL;
135
136 spin_lock(&fq->q.lock);
137
138 if (fq->q.last_in & INET_FRAG_COMPLETE)
139 goto out;
140
141 inet_frag_kill(&fq->q, frags);
142
143 rcu_read_lock();
144 dev = dev_get_by_index_rcu(net, fq->iif);
145 if (!dev)
146 goto out_rcu_unlock;
147
148 IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
149 IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
150
151 /* Don't send error if the first segment did not arrive. */
152 if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
153 goto out_rcu_unlock;
154
155 /*
156 But use as source device on which LAST ARRIVED
157 segment was received. And do not use fq->dev
158 pointer directly, device might already disappeared.
159 */
160 fq->q.fragments->dev = dev;
161 icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
162out_rcu_unlock:
163 rcu_read_unlock();
164out:
165 spin_unlock(&fq->q.lock);
166 inet_frag_put(&fq->q, frags);
167}
168EXPORT_SYMBOL(ip6_expire_frag_queue);
169
170static void ip6_frag_expire(unsigned long data)
171{
172 struct frag_queue *fq;
173 struct net *net;
174
175 fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
176 net = container_of(fq->q.net, struct net, ipv6.frags);
177
178 ip6_expire_frag_queue(net, fq, &ip6_frags);
179}
180
181static __inline__ struct frag_queue *
182fq_find(struct net *net, __be32 id, const struct in6_addr *src,
183 const struct in6_addr *dst, u8 ecn)
184{
185 struct inet_frag_queue *q;
186 struct ip6_create_arg arg;
187 unsigned int hash;
188
189 arg.id = id;
190 arg.user = IP6_DEFRAG_LOCAL_DELIVER;
191 arg.src = src;
192 arg.dst = dst;
193 arg.ecn = ecn;
194
195 read_lock(&ip6_frags.lock);
196 hash = inet6_hash_frag(id, src, dst);
197
198 q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
199 if (IS_ERR_OR_NULL(q)) {
200 inet_frag_maybe_warn_overflow(q, pr_fmt());
201 return NULL;
202 }
203 return container_of(q, struct frag_queue, q);
204}
205
206static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
207 struct frag_hdr *fhdr, int nhoff)
208{
209 struct sk_buff *prev, *next;
210 struct net_device *dev;
211 int offset, end;
212 struct net *net = dev_net(skb_dst(skb)->dev);
213 u8 ecn;
214
215 if (fq->q.last_in & INET_FRAG_COMPLETE)
216 goto err;
217
218 offset = ntohs(fhdr->frag_off) & ~0x7;
219 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
220 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
221
222 if ((unsigned int)end > IPV6_MAXPLEN) {
223 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
224 IPSTATS_MIB_INHDRERRORS);
225 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
226 ((u8 *)&fhdr->frag_off -
227 skb_network_header(skb)));
228 return -1;
229 }
230
231 ecn = ip6_frag_ecn(ipv6_hdr(skb));
232
233 if (skb->ip_summed == CHECKSUM_COMPLETE) {
234 const unsigned char *nh = skb_network_header(skb);
235 skb->csum = csum_sub(skb->csum,
236 csum_partial(nh, (u8 *)(fhdr + 1) - nh,
237 0));
238 }
239
240 /* Is this the final fragment? */
241 if (!(fhdr->frag_off & htons(IP6_MF))) {
242 /* If we already have some bits beyond end
243 * or have different end, the segment is corrupted.
244 */
245 if (end < fq->q.len ||
246 ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
247 goto err;
248 fq->q.last_in |= INET_FRAG_LAST_IN;
249 fq->q.len = end;
250 } else {
251 /* Check if the fragment is rounded to 8 bytes.
252 * Required by the RFC.
253 */
254 if (end & 0x7) {
255 /* RFC2460 says always send parameter problem in
256 * this case. -DaveM
257 */
258 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
259 IPSTATS_MIB_INHDRERRORS);
260 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
261 offsetof(struct ipv6hdr, payload_len));
262 return -1;
263 }
264 if (end > fq->q.len) {
265 /* Some bits beyond end -> corruption. */
266 if (fq->q.last_in & INET_FRAG_LAST_IN)
267 goto err;
268 fq->q.len = end;
269 }
270 }
271
272 if (end == offset)
273 goto err;
274
275 /* Point into the IP datagram 'data' part. */
276 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
277 goto err;
278
279 if (pskb_trim_rcsum(skb, end - offset))
280 goto err;
281
282 /* Find out which fragments are in front and at the back of us
283 * in the chain of fragments so far. We must know where to put
284 * this fragment, right?
285 */
286 prev = fq->q.fragments_tail;
287 if (!prev || FRAG6_CB(prev)->offset < offset) {
288 next = NULL;
289 goto found;
290 }
291 prev = NULL;
292 for(next = fq->q.fragments; next != NULL; next = next->next) {
293 if (FRAG6_CB(next)->offset >= offset)
294 break; /* bingo! */
295 prev = next;
296 }
297
298found:
299 /* RFC5722, Section 4, amended by Errata ID : 3089
300 * When reassembling an IPv6 datagram, if
301 * one or more its constituent fragments is determined to be an
302 * overlapping fragment, the entire datagram (and any constituent
303 * fragments) MUST be silently discarded.
304 */
305
306 /* Check for overlap with preceding fragment. */
307 if (prev &&
308 (FRAG6_CB(prev)->offset + prev->len) > offset)
309 goto discard_fq;
310
311 /* Look for overlap with succeeding segment. */
312 if (next && FRAG6_CB(next)->offset < end)
313 goto discard_fq;
314
315 FRAG6_CB(skb)->offset = offset;
316
317 /* Insert this fragment in the chain of fragments. */
318 skb->next = next;
319 if (!next)
320 fq->q.fragments_tail = skb;
321 if (prev)
322 prev->next = skb;
323 else
324 fq->q.fragments = skb;
325
326 dev = skb->dev;
327 if (dev) {
328 fq->iif = dev->ifindex;
329 skb->dev = NULL;
330 }
331 fq->q.stamp = skb->tstamp;
332 fq->q.meat += skb->len;
333 fq->ecn |= ecn;
334 add_frag_mem_limit(&fq->q, skb->truesize);
335
336 /* The first fragment.
337 * nhoffset is obtained from the first fragment, of course.
338 */
339 if (offset == 0) {
340 fq->nhoffset = nhoff;
341 fq->q.last_in |= INET_FRAG_FIRST_IN;
342 }
343
344 if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
345 fq->q.meat == fq->q.len) {
346 int res;
347 unsigned long orefdst = skb->_skb_refdst;
348
349 skb->_skb_refdst = 0UL;
350 res = ip6_frag_reasm(fq, prev, dev);
351 skb->_skb_refdst = orefdst;
352 return res;
353 }
354
355 skb_dst_drop(skb);
356 inet_frag_lru_move(&fq->q);
357 return -1;
358
359discard_fq:
360 inet_frag_kill(&fq->q, &ip6_frags);
361err:
362 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
363 IPSTATS_MIB_REASMFAILS);
364 kfree_skb(skb);
365 return -1;
366}
367
368/*
369 * Check if this packet is complete.
370 * Returns NULL on failure by any reason, and pointer
371 * to current nexthdr field in reassembled frame.
372 *
373 * It is called with locked fq, and caller must check that
374 * queue is eligible for reassembly i.e. it is not COMPLETE,
375 * the last and the first frames arrived and all the bits are here.
376 */
377static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
378 struct net_device *dev)
379{
380 struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
381 struct sk_buff *fp, *head = fq->q.fragments;
382 int payload_len;
383 unsigned int nhoff;
384 int sum_truesize;
385 u8 ecn;
386
387 inet_frag_kill(&fq->q, &ip6_frags);
388
389 ecn = ip_frag_ecn_table[fq->ecn];
390 if (unlikely(ecn == 0xff))
391 goto out_fail;
392
393 /* Make the one we just received the head. */
394 if (prev) {
395 head = prev->next;
396 fp = skb_clone(head, GFP_ATOMIC);
397
398 if (!fp)
399 goto out_oom;
400
401 fp->next = head->next;
402 if (!fp->next)
403 fq->q.fragments_tail = fp;
404 prev->next = fp;
405
406 skb_morph(head, fq->q.fragments);
407 head->next = fq->q.fragments->next;
408
409 consume_skb(fq->q.fragments);
410 fq->q.fragments = head;
411 }
412
413 WARN_ON(head == NULL);
414 WARN_ON(FRAG6_CB(head)->offset != 0);
415
416 /* Unfragmented part is taken from the first segment. */
417 payload_len = ((head->data - skb_network_header(head)) -
418 sizeof(struct ipv6hdr) + fq->q.len -
419 sizeof(struct frag_hdr));
420 if (payload_len > IPV6_MAXPLEN)
421 goto out_oversize;
422
423 /* Head of list must not be cloned. */
424 if (skb_unclone(head, GFP_ATOMIC))
425 goto out_oom;
426
427 /* If the first fragment is fragmented itself, we split
428 * it to two chunks: the first with data and paged part
429 * and the second, holding only fragments. */
430 if (skb_has_frag_list(head)) {
431 struct sk_buff *clone;
432 int i, plen = 0;
433
434 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
435 goto out_oom;
436 clone->next = head->next;
437 head->next = clone;
438 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
439 skb_frag_list_init(head);
440 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
441 plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
442 clone->len = clone->data_len = head->data_len - plen;
443 head->data_len -= clone->len;
444 head->len -= clone->len;
445 clone->csum = 0;
446 clone->ip_summed = head->ip_summed;
447 add_frag_mem_limit(&fq->q, clone->truesize);
448 }
449
450 /* We have to remove fragment header from datagram and to relocate
451 * header in order to calculate ICV correctly. */
452 nhoff = fq->nhoffset;
453 skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
454 memmove(head->head + sizeof(struct frag_hdr), head->head,
455 (head->data - head->head) - sizeof(struct frag_hdr));
456 head->mac_header += sizeof(struct frag_hdr);
457 head->network_header += sizeof(struct frag_hdr);
458
459 skb_reset_transport_header(head);
460 skb_push(head, head->data - skb_network_header(head));
461
462 sum_truesize = head->truesize;
463 for (fp = head->next; fp;) {
464 bool headstolen;
465 int delta;
466 struct sk_buff *next = fp->next;
467
468 sum_truesize += fp->truesize;
469 if (head->ip_summed != fp->ip_summed)
470 head->ip_summed = CHECKSUM_NONE;
471 else if (head->ip_summed == CHECKSUM_COMPLETE)
472 head->csum = csum_add(head->csum, fp->csum);
473
474 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
475 kfree_skb_partial(fp, headstolen);
476 } else {
477 if (!skb_shinfo(head)->frag_list)
478 skb_shinfo(head)->frag_list = fp;
479 head->data_len += fp->len;
480 head->len += fp->len;
481 head->truesize += fp->truesize;
482 }
483 fp = next;
484 }
485 sub_frag_mem_limit(&fq->q, sum_truesize);
486
487 head->next = NULL;
488 head->dev = dev;
489 head->tstamp = fq->q.stamp;
490 ipv6_hdr(head)->payload_len = htons(payload_len);
491 ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
492 IP6CB(head)->nhoff = nhoff;
493 IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
494
495 /* Yes, and fold redundant checksum back. 8) */
496 if (head->ip_summed == CHECKSUM_COMPLETE)
497 head->csum = csum_partial(skb_network_header(head),
498 skb_network_header_len(head),
499 head->csum);
500
501 rcu_read_lock();
502 IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
503 rcu_read_unlock();
504 fq->q.fragments = NULL;
505 fq->q.fragments_tail = NULL;
506 return 1;
507
508out_oversize:
509 net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
510 goto out_fail;
511out_oom:
512 net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
513out_fail:
514 rcu_read_lock();
515 IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
516 rcu_read_unlock();
517 return -1;
518}
519
520static int ipv6_frag_rcv(struct sk_buff *skb)
521{
522 struct frag_hdr *fhdr;
523 struct frag_queue *fq;
524 const struct ipv6hdr *hdr = ipv6_hdr(skb);
525 struct net *net = dev_net(skb_dst(skb)->dev);
526 int evicted;
527
528 if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
529 goto fail_hdr;
530
531 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
532
533 /* Jumbo payload inhibits frag. header */
534 if (hdr->payload_len==0)
535 goto fail_hdr;
536
537 if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
538 sizeof(struct frag_hdr))))
539 goto fail_hdr;
540
541 hdr = ipv6_hdr(skb);
542 fhdr = (struct frag_hdr *)skb_transport_header(skb);
543
544 if (!(fhdr->frag_off & htons(0xFFF9))) {
545 /* It is not a fragmented frame */
546 skb->transport_header += sizeof(struct frag_hdr);
547 IP6_INC_STATS_BH(net,
548 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
549
550 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
551 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
552 return 1;
553 }
554
555 evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags, false);
556 if (evicted)
557 IP6_ADD_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
558 IPSTATS_MIB_REASMFAILS, evicted);
559
560 fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
561 ip6_frag_ecn(hdr));
562 if (fq != NULL) {
563 int ret;
564
565 spin_lock(&fq->q.lock);
566
567 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
568
569 spin_unlock(&fq->q.lock);
570 inet_frag_put(&fq->q, &ip6_frags);
571 return ret;
572 }
573
574 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
575 kfree_skb(skb);
576 return -1;
577
578fail_hdr:
579 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
580 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
581 return -1;
582}
583
584static const struct inet6_protocol frag_protocol =
585{
586 .handler = ipv6_frag_rcv,
587 .flags = INET6_PROTO_NOPOLICY,
588};
589
590#ifdef CONFIG_SYSCTL
591static struct ctl_table ip6_frags_ns_ctl_table[] = {
592 {
593 .procname = "ip6frag_high_thresh",
594 .data = &init_net.ipv6.frags.high_thresh,
595 .maxlen = sizeof(int),
596 .mode = 0644,
597 .proc_handler = proc_dointvec
598 },
599 {
600 .procname = "ip6frag_low_thresh",
601 .data = &init_net.ipv6.frags.low_thresh,
602 .maxlen = sizeof(int),
603 .mode = 0644,
604 .proc_handler = proc_dointvec
605 },
606 {
607 .procname = "ip6frag_time",
608 .data = &init_net.ipv6.frags.timeout,
609 .maxlen = sizeof(int),
610 .mode = 0644,
611 .proc_handler = proc_dointvec_jiffies,
612 },
613 { }
614};
615
616static struct ctl_table ip6_frags_ctl_table[] = {
617 {
618 .procname = "ip6frag_secret_interval",
619 .data = &ip6_frags.secret_interval,
620 .maxlen = sizeof(int),
621 .mode = 0644,
622 .proc_handler = proc_dointvec_jiffies,
623 },
624 { }
625};
626
627static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
628{
629 struct ctl_table *table;
630 struct ctl_table_header *hdr;
631
632 table = ip6_frags_ns_ctl_table;
633 if (!net_eq(net, &init_net)) {
634 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
635 if (table == NULL)
636 goto err_alloc;
637
638 table[0].data = &net->ipv6.frags.high_thresh;
639 table[1].data = &net->ipv6.frags.low_thresh;
640 table[2].data = &net->ipv6.frags.timeout;
641
642 /* Don't export sysctls to unprivileged users */
643 if (net->user_ns != &init_user_ns)
644 table[0].procname = NULL;
645 }
646
647 hdr = register_net_sysctl(net, "net/ipv6", table);
648 if (hdr == NULL)
649 goto err_reg;
650
651 net->ipv6.sysctl.frags_hdr = hdr;
652 return 0;
653
654err_reg:
655 if (!net_eq(net, &init_net))
656 kfree(table);
657err_alloc:
658 return -ENOMEM;
659}
660
661static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
662{
663 struct ctl_table *table;
664
665 table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
666 unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
667 if (!net_eq(net, &init_net))
668 kfree(table);
669}
670
671static struct ctl_table_header *ip6_ctl_header;
672
673static int ip6_frags_sysctl_register(void)
674{
675 ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
676 ip6_frags_ctl_table);
677 return ip6_ctl_header == NULL ? -ENOMEM : 0;
678}
679
680static void ip6_frags_sysctl_unregister(void)
681{
682 unregister_net_sysctl_table(ip6_ctl_header);
683}
684#else
685static inline int ip6_frags_ns_sysctl_register(struct net *net)
686{
687 return 0;
688}
689
690static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
691{
692}
693
694static inline int ip6_frags_sysctl_register(void)
695{
696 return 0;
697}
698
699static inline void ip6_frags_sysctl_unregister(void)
700{
701}
702#endif
703
704static int __net_init ipv6_frags_init_net(struct net *net)
705{
706 net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
707 net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
708 net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
709
710 inet_frags_init_net(&net->ipv6.frags);
711
712 return ip6_frags_ns_sysctl_register(net);
713}
714
715static void __net_exit ipv6_frags_exit_net(struct net *net)
716{
717 ip6_frags_ns_sysctl_unregister(net);
718 inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
719}
720
721static struct pernet_operations ip6_frags_ops = {
722 .init = ipv6_frags_init_net,
723 .exit = ipv6_frags_exit_net,
724};
725
726int __init ipv6_frag_init(void)
727{
728 int ret;
729
730 ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
731 if (ret)
732 goto out;
733
734 ret = ip6_frags_sysctl_register();
735 if (ret)
736 goto err_sysctl;
737
738 ret = register_pernet_subsys(&ip6_frags_ops);
739 if (ret)
740 goto err_pernet;
741
742 ip6_frags.hashfn = ip6_hashfn;
743 ip6_frags.constructor = ip6_frag_init;
744 ip6_frags.destructor = NULL;
745 ip6_frags.skb_free = NULL;
746 ip6_frags.qsize = sizeof(struct frag_queue);
747 ip6_frags.match = ip6_frag_match;
748 ip6_frags.frag_expire = ip6_frag_expire;
749 ip6_frags.secret_interval = 10 * 60 * HZ;
750 inet_frags_init(&ip6_frags);
751out:
752 return ret;
753
754err_pernet:
755 ip6_frags_sysctl_unregister();
756err_sysctl:
757 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
758 goto out;
759}
760
761void ipv6_frag_exit(void)
762{
763 inet_frags_fini(&ip6_frags);
764 ip6_frags_sysctl_unregister();
765 unregister_pernet_subsys(&ip6_frags_ops);
766 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
767}