This source file includes following definitions.
- ip6_frag_ecn
- ip6_frag_expire
- fq_find
- ip6_frag_queue
- ip6_frag_reasm
- ipv6_frag_rcv
- ip6_frags_ns_sysctl_register
- ip6_frags_ns_sysctl_unregister
- ip6_frags_sysctl_register
- ip6_frags_sysctl_unregister
- ip6_frags_ns_sysctl_register
- ip6_frags_ns_sysctl_unregister
- ip6_frags_sysctl_register
- ip6_frags_sysctl_unregister
- ipv6_frags_init_net
- ipv6_frags_pre_exit_net
- ipv6_frags_exit_net
- ipv6_frag_init
- ipv6_frag_exit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
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
46 #include <net/sock.h>
47 #include <net/snmp.h>
48
49 #include <net/ipv6.h>
50 #include <net/ip6_route.h>
51 #include <net/protocol.h>
52 #include <net/transp_v6.h>
53 #include <net/rawv6.h>
54 #include <net/ndisc.h>
55 #include <net/addrconf.h>
56 #include <net/ipv6_frag.h>
57 #include <net/inet_ecn.h>
58
59 static const char ip6_frag_cache_name[] = "ip6-frags";
60
61 static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
62 {
63 return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
64 }
65
66 static struct inet_frags ip6_frags;
67
68 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
69 struct sk_buff *prev_tail, struct net_device *dev);
70
71 static void ip6_frag_expire(struct timer_list *t)
72 {
73 struct inet_frag_queue *frag = from_timer(frag, t, timer);
74 struct frag_queue *fq;
75
76 fq = container_of(frag, struct frag_queue, q);
77
78 ip6frag_expire_frag_queue(fq->q.fqdir->net, fq);
79 }
80
81 static struct frag_queue *
82 fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif)
83 {
84 struct frag_v6_compare_key key = {
85 .id = id,
86 .saddr = hdr->saddr,
87 .daddr = hdr->daddr,
88 .user = IP6_DEFRAG_LOCAL_DELIVER,
89 .iif = iif,
90 };
91 struct inet_frag_queue *q;
92
93 if (!(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_MULTICAST |
94 IPV6_ADDR_LINKLOCAL)))
95 key.iif = 0;
96
97 q = inet_frag_find(net->ipv6.fqdir, &key);
98 if (!q)
99 return NULL;
100
101 return container_of(q, struct frag_queue, q);
102 }
103
104 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
105 struct frag_hdr *fhdr, int nhoff,
106 u32 *prob_offset)
107 {
108 struct net *net = dev_net(skb_dst(skb)->dev);
109 int offset, end, fragsize;
110 struct sk_buff *prev_tail;
111 struct net_device *dev;
112 int err = -ENOENT;
113 u8 ecn;
114
115 if (fq->q.flags & INET_FRAG_COMPLETE)
116 goto err;
117
118 err = -EINVAL;
119 offset = ntohs(fhdr->frag_off) & ~0x7;
120 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
121 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
122
123 if ((unsigned int)end > IPV6_MAXPLEN) {
124 *prob_offset = (u8 *)&fhdr->frag_off - skb_network_header(skb);
125
126
127
128 return -1;
129 }
130
131 ecn = ip6_frag_ecn(ipv6_hdr(skb));
132
133 if (skb->ip_summed == CHECKSUM_COMPLETE) {
134 const unsigned char *nh = skb_network_header(skb);
135 skb->csum = csum_sub(skb->csum,
136 csum_partial(nh, (u8 *)(fhdr + 1) - nh,
137 0));
138 }
139
140
141 if (!(fhdr->frag_off & htons(IP6_MF))) {
142
143
144
145 if (end < fq->q.len ||
146 ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
147 goto discard_fq;
148 fq->q.flags |= INET_FRAG_LAST_IN;
149 fq->q.len = end;
150 } else {
151
152
153
154 if (end & 0x7) {
155
156
157
158 *prob_offset = offsetof(struct ipv6hdr, payload_len);
159 return -1;
160 }
161 if (end > fq->q.len) {
162
163 if (fq->q.flags & INET_FRAG_LAST_IN)
164 goto discard_fq;
165 fq->q.len = end;
166 }
167 }
168
169 if (end == offset)
170 goto discard_fq;
171
172 err = -ENOMEM;
173
174 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
175 goto discard_fq;
176
177 err = pskb_trim_rcsum(skb, end - offset);
178 if (err)
179 goto discard_fq;
180
181
182 dev = skb->dev;
183
184 barrier();
185
186 prev_tail = fq->q.fragments_tail;
187 err = inet_frag_queue_insert(&fq->q, skb, offset, end);
188 if (err)
189 goto insert_error;
190
191 if (dev)
192 fq->iif = dev->ifindex;
193
194 fq->q.stamp = skb->tstamp;
195 fq->q.meat += skb->len;
196 fq->ecn |= ecn;
197 add_frag_mem_limit(fq->q.fqdir, skb->truesize);
198
199 fragsize = -skb_network_offset(skb) + skb->len;
200 if (fragsize > fq->q.max_size)
201 fq->q.max_size = fragsize;
202
203
204
205
206 if (offset == 0) {
207 fq->nhoffset = nhoff;
208 fq->q.flags |= INET_FRAG_FIRST_IN;
209 }
210
211 if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
212 fq->q.meat == fq->q.len) {
213 unsigned long orefdst = skb->_skb_refdst;
214
215 skb->_skb_refdst = 0UL;
216 err = ip6_frag_reasm(fq, skb, prev_tail, dev);
217 skb->_skb_refdst = orefdst;
218 return err;
219 }
220
221 skb_dst_drop(skb);
222 return -EINPROGRESS;
223
224 insert_error:
225 if (err == IPFRAG_DUP) {
226 kfree_skb(skb);
227 return -EINVAL;
228 }
229 err = -EINVAL;
230 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
231 IPSTATS_MIB_REASM_OVERLAPS);
232 discard_fq:
233 inet_frag_kill(&fq->q);
234 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
235 IPSTATS_MIB_REASMFAILS);
236 err:
237 kfree_skb(skb);
238 return err;
239 }
240
241
242
243
244
245
246
247
248 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
249 struct sk_buff *prev_tail, struct net_device *dev)
250 {
251 struct net *net = fq->q.fqdir->net;
252 unsigned int nhoff;
253 void *reasm_data;
254 int payload_len;
255 u8 ecn;
256
257 inet_frag_kill(&fq->q);
258
259 ecn = ip_frag_ecn_table[fq->ecn];
260 if (unlikely(ecn == 0xff))
261 goto out_fail;
262
263 reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
264 if (!reasm_data)
265 goto out_oom;
266
267 payload_len = ((skb->data - skb_network_header(skb)) -
268 sizeof(struct ipv6hdr) + fq->q.len -
269 sizeof(struct frag_hdr));
270 if (payload_len > IPV6_MAXPLEN)
271 goto out_oversize;
272
273
274
275 nhoff = fq->nhoffset;
276 skb_network_header(skb)[nhoff] = skb_transport_header(skb)[0];
277 memmove(skb->head + sizeof(struct frag_hdr), skb->head,
278 (skb->data - skb->head) - sizeof(struct frag_hdr));
279 if (skb_mac_header_was_set(skb))
280 skb->mac_header += sizeof(struct frag_hdr);
281 skb->network_header += sizeof(struct frag_hdr);
282
283 skb_reset_transport_header(skb);
284
285 inet_frag_reasm_finish(&fq->q, skb, reasm_data, true);
286
287 skb->dev = dev;
288 ipv6_hdr(skb)->payload_len = htons(payload_len);
289 ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn);
290 IP6CB(skb)->nhoff = nhoff;
291 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
292 IP6CB(skb)->frag_max_size = fq->q.max_size;
293
294
295 skb_postpush_rcsum(skb, skb_network_header(skb),
296 skb_network_header_len(skb));
297
298 rcu_read_lock();
299 __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMOKS);
300 rcu_read_unlock();
301 fq->q.rb_fragments = RB_ROOT;
302 fq->q.fragments_tail = NULL;
303 fq->q.last_run_head = NULL;
304 return 1;
305
306 out_oversize:
307 net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
308 goto out_fail;
309 out_oom:
310 net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
311 out_fail:
312 rcu_read_lock();
313 __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMFAILS);
314 rcu_read_unlock();
315 inet_frag_kill(&fq->q);
316 return -1;
317 }
318
319 static int ipv6_frag_rcv(struct sk_buff *skb)
320 {
321 struct frag_hdr *fhdr;
322 struct frag_queue *fq;
323 const struct ipv6hdr *hdr = ipv6_hdr(skb);
324 struct net *net = dev_net(skb_dst(skb)->dev);
325 int iif;
326
327 if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
328 goto fail_hdr;
329
330 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
331
332
333 if (hdr->payload_len == 0)
334 goto fail_hdr;
335
336 if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
337 sizeof(struct frag_hdr))))
338 goto fail_hdr;
339
340 hdr = ipv6_hdr(skb);
341 fhdr = (struct frag_hdr *)skb_transport_header(skb);
342
343 if (!(fhdr->frag_off & htons(0xFFF9))) {
344
345 skb->transport_header += sizeof(struct frag_hdr);
346 __IP6_INC_STATS(net,
347 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
348
349 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
350 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
351 return 1;
352 }
353
354 iif = skb->dev ? skb->dev->ifindex : 0;
355 fq = fq_find(net, fhdr->identification, hdr, iif);
356 if (fq) {
357 u32 prob_offset = 0;
358 int ret;
359
360 spin_lock(&fq->q.lock);
361
362 fq->iif = iif;
363 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff,
364 &prob_offset);
365
366 spin_unlock(&fq->q.lock);
367 inet_frag_put(&fq->q);
368 if (prob_offset) {
369 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
370 IPSTATS_MIB_INHDRERRORS);
371
372 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, prob_offset);
373 }
374 return ret;
375 }
376
377 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
378 kfree_skb(skb);
379 return -1;
380
381 fail_hdr:
382 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
383 IPSTATS_MIB_INHDRERRORS);
384 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
385 return -1;
386 }
387
388 static const struct inet6_protocol frag_protocol = {
389 .handler = ipv6_frag_rcv,
390 .flags = INET6_PROTO_NOPOLICY,
391 };
392
393 #ifdef CONFIG_SYSCTL
394
395 static struct ctl_table ip6_frags_ns_ctl_table[] = {
396 {
397 .procname = "ip6frag_high_thresh",
398 .maxlen = sizeof(unsigned long),
399 .mode = 0644,
400 .proc_handler = proc_doulongvec_minmax,
401 },
402 {
403 .procname = "ip6frag_low_thresh",
404 .maxlen = sizeof(unsigned long),
405 .mode = 0644,
406 .proc_handler = proc_doulongvec_minmax,
407 },
408 {
409 .procname = "ip6frag_time",
410 .maxlen = sizeof(int),
411 .mode = 0644,
412 .proc_handler = proc_dointvec_jiffies,
413 },
414 { }
415 };
416
417
418 static int ip6_frags_secret_interval_unused;
419 static struct ctl_table ip6_frags_ctl_table[] = {
420 {
421 .procname = "ip6frag_secret_interval",
422 .data = &ip6_frags_secret_interval_unused,
423 .maxlen = sizeof(int),
424 .mode = 0644,
425 .proc_handler = proc_dointvec_jiffies,
426 },
427 { }
428 };
429
430 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
431 {
432 struct ctl_table *table;
433 struct ctl_table_header *hdr;
434
435 table = ip6_frags_ns_ctl_table;
436 if (!net_eq(net, &init_net)) {
437 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
438 if (!table)
439 goto err_alloc;
440
441 }
442 table[0].data = &net->ipv6.fqdir->high_thresh;
443 table[0].extra1 = &net->ipv6.fqdir->low_thresh;
444 table[1].data = &net->ipv6.fqdir->low_thresh;
445 table[1].extra2 = &net->ipv6.fqdir->high_thresh;
446 table[2].data = &net->ipv6.fqdir->timeout;
447
448 hdr = register_net_sysctl(net, "net/ipv6", table);
449 if (!hdr)
450 goto err_reg;
451
452 net->ipv6.sysctl.frags_hdr = hdr;
453 return 0;
454
455 err_reg:
456 if (!net_eq(net, &init_net))
457 kfree(table);
458 err_alloc:
459 return -ENOMEM;
460 }
461
462 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
463 {
464 struct ctl_table *table;
465
466 table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
467 unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
468 if (!net_eq(net, &init_net))
469 kfree(table);
470 }
471
472 static struct ctl_table_header *ip6_ctl_header;
473
474 static int ip6_frags_sysctl_register(void)
475 {
476 ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
477 ip6_frags_ctl_table);
478 return ip6_ctl_header == NULL ? -ENOMEM : 0;
479 }
480
481 static void ip6_frags_sysctl_unregister(void)
482 {
483 unregister_net_sysctl_table(ip6_ctl_header);
484 }
485 #else
486 static int ip6_frags_ns_sysctl_register(struct net *net)
487 {
488 return 0;
489 }
490
491 static void ip6_frags_ns_sysctl_unregister(struct net *net)
492 {
493 }
494
495 static int ip6_frags_sysctl_register(void)
496 {
497 return 0;
498 }
499
500 static void ip6_frags_sysctl_unregister(void)
501 {
502 }
503 #endif
504
505 static int __net_init ipv6_frags_init_net(struct net *net)
506 {
507 int res;
508
509 res = fqdir_init(&net->ipv6.fqdir, &ip6_frags, net);
510 if (res < 0)
511 return res;
512
513 net->ipv6.fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
514 net->ipv6.fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
515 net->ipv6.fqdir->timeout = IPV6_FRAG_TIMEOUT;
516
517 res = ip6_frags_ns_sysctl_register(net);
518 if (res < 0)
519 fqdir_exit(net->ipv6.fqdir);
520 return res;
521 }
522
523 static void __net_exit ipv6_frags_pre_exit_net(struct net *net)
524 {
525 fqdir_pre_exit(net->ipv6.fqdir);
526 }
527
528 static void __net_exit ipv6_frags_exit_net(struct net *net)
529 {
530 ip6_frags_ns_sysctl_unregister(net);
531 fqdir_exit(net->ipv6.fqdir);
532 }
533
534 static struct pernet_operations ip6_frags_ops = {
535 .init = ipv6_frags_init_net,
536 .pre_exit = ipv6_frags_pre_exit_net,
537 .exit = ipv6_frags_exit_net,
538 };
539
540 static const struct rhashtable_params ip6_rhash_params = {
541 .head_offset = offsetof(struct inet_frag_queue, node),
542 .hashfn = ip6frag_key_hashfn,
543 .obj_hashfn = ip6frag_obj_hashfn,
544 .obj_cmpfn = ip6frag_obj_cmpfn,
545 .automatic_shrinking = true,
546 };
547
548 int __init ipv6_frag_init(void)
549 {
550 int ret;
551
552 ip6_frags.constructor = ip6frag_init;
553 ip6_frags.destructor = NULL;
554 ip6_frags.qsize = sizeof(struct frag_queue);
555 ip6_frags.frag_expire = ip6_frag_expire;
556 ip6_frags.frags_cache_name = ip6_frag_cache_name;
557 ip6_frags.rhash_params = ip6_rhash_params;
558 ret = inet_frags_init(&ip6_frags);
559 if (ret)
560 goto out;
561
562 ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
563 if (ret)
564 goto err_protocol;
565
566 ret = ip6_frags_sysctl_register();
567 if (ret)
568 goto err_sysctl;
569
570 ret = register_pernet_subsys(&ip6_frags_ops);
571 if (ret)
572 goto err_pernet;
573
574 out:
575 return ret;
576
577 err_pernet:
578 ip6_frags_sysctl_unregister();
579 err_sysctl:
580 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
581 err_protocol:
582 inet_frags_fini(&ip6_frags);
583 goto out;
584 }
585
586 void ipv6_frag_exit(void)
587 {
588 ip6_frags_sysctl_unregister();
589 unregister_pernet_subsys(&ip6_frags_ops);
590 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
591 inet_frags_fini(&ip6_frags);
592 }