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s390: add 'install' target to 'make help'
[linux/fpc-iii.git] / net / ieee802154 / 6lowpan / reassembly.c
blob6b437e8760d314c5314cc1deb2d5d13dff0f2ec8
1 /* 6LoWPAN fragment reassembly
2 *
3 *
4 * Authors:
5 * Alexander Aring <aar@pengutronix.de>
6 *
7 * Based on: net/ipv6/reassembly.c
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15 #define pr_fmt(fmt) "6LoWPAN: " fmt
16
17 #include <linux/net.h>
18 #include <linux/list.h>
19 #include <linux/netdevice.h>
20 #include <linux/random.h>
21 #include <linux/jhash.h>
22 #include <linux/skbuff.h>
23 #include <linux/slab.h>
24 #include <linux/export.h>
25
26 #include <net/ieee802154_netdev.h>
27 #include <net/6lowpan.h>
28 #include <net/ipv6.h>
29 #include <net/inet_frag.h>
30
31 #include "6lowpan_i.h"
32
33 static const char lowpan_frags_cache_name[] = "lowpan-frags";
34
35 static struct inet_frags lowpan_frags;
36
37 static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
38 struct sk_buff *prev, struct net_device *ldev);
39
40 static unsigned int lowpan_hash_frag(u16 tag, u16 d_size,
41 const struct ieee802154_addr *saddr,
42 const struct ieee802154_addr *daddr)
43 {
44 net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd));
45 return jhash_3words(ieee802154_addr_hash(saddr),
46 ieee802154_addr_hash(daddr),
47 (__force u32)(tag + (d_size << 16)),
48 lowpan_frags.rnd);
49 }
50
51 static unsigned int lowpan_hashfn(const struct inet_frag_queue *q)
52 {
53 const struct lowpan_frag_queue *fq;
54
55 fq = container_of(q, struct lowpan_frag_queue, q);
56 return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr);
57 }
58
59 static bool lowpan_frag_match(const struct inet_frag_queue *q, const void *a)
60 {
61 const struct lowpan_frag_queue *fq;
62 const struct lowpan_create_arg *arg = a;
63
64 fq = container_of(q, struct lowpan_frag_queue, q);
65 return fq->tag == arg->tag && fq->d_size == arg->d_size &&
66 ieee802154_addr_equal(&fq->saddr, arg->src) &&
67 ieee802154_addr_equal(&fq->daddr, arg->dst);
68 }
69
70 static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
71 {
72 const struct lowpan_create_arg *arg = a;
73 struct lowpan_frag_queue *fq;
74
75 fq = container_of(q, struct lowpan_frag_queue, q);
76
77 fq->tag = arg->tag;
78 fq->d_size = arg->d_size;
79 fq->saddr = *arg->src;
80 fq->daddr = *arg->dst;
81 }
82
83 static void lowpan_frag_expire(unsigned long data)
84 {
85 struct frag_queue *fq;
86 struct net *net;
87
88 fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
89 net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags);
90
91 spin_lock(&fq->q.lock);
92
93 if (fq->q.flags & INET_FRAG_COMPLETE)
94 goto out;
95
96 inet_frag_kill(&fq->q, &lowpan_frags);
97 out:
98 spin_unlock(&fq->q.lock);
99 inet_frag_put(&fq->q, &lowpan_frags);
100 }
101
102 static inline struct lowpan_frag_queue *
103 fq_find(struct net *net, const struct lowpan_802154_cb *cb,
104 const struct ieee802154_addr *src,
105 const struct ieee802154_addr *dst)
106 {
107 struct inet_frag_queue *q;
108 struct lowpan_create_arg arg;
109 unsigned int hash;
110 struct netns_ieee802154_lowpan *ieee802154_lowpan =
111 net_ieee802154_lowpan(net);
112
113 arg.tag = cb->d_tag;
114 arg.d_size = cb->d_size;
115 arg.src = src;
116 arg.dst = dst;
117
118 hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst);
119
120 q = inet_frag_find(&ieee802154_lowpan->frags,
121 &lowpan_frags, &arg, hash);
122 if (IS_ERR_OR_NULL(q)) {
123 inet_frag_maybe_warn_overflow(q, pr_fmt());
124 return NULL;
125 }
126 return container_of(q, struct lowpan_frag_queue, q);
127 }
128
129 static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
130 struct sk_buff *skb, u8 frag_type)
131 {
132 struct sk_buff *prev, *next;
133 struct net_device *ldev;
134 int end, offset;
135
136 if (fq->q.flags & INET_FRAG_COMPLETE)
137 goto err;
138
139 offset = lowpan_802154_cb(skb)->d_offset << 3;
140 end = lowpan_802154_cb(skb)->d_size;
141
142 /* Is this the final fragment? */
143 if (offset + skb->len == end) {
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 err;
150 fq->q.flags |= INET_FRAG_LAST_IN;
151 fq->q.len = end;
152 } else {
153 if (end > fq->q.len) {
154 /* Some bits beyond end -> corruption. */
155 if (fq->q.flags & INET_FRAG_LAST_IN)
156 goto err;
157 fq->q.len = end;
158 }
159 }
160
161 /* Find out which fragments are in front and at the back of us
162 * in the chain of fragments so far. We must know where to put
163 * this fragment, right?
164 */
165 prev = fq->q.fragments_tail;
166 if (!prev ||
167 lowpan_802154_cb(prev)->d_offset <
168 lowpan_802154_cb(skb)->d_offset) {
169 next = NULL;
170 goto found;
171 }
172 prev = NULL;
173 for (next = fq->q.fragments; next != NULL; next = next->next) {
174 if (lowpan_802154_cb(next)->d_offset >=
175 lowpan_802154_cb(skb)->d_offset)
176 break; /* bingo! */
177 prev = next;
178 }
179
180 found:
181 /* Insert this fragment in the chain of fragments. */
182 skb->next = next;
183 if (!next)
184 fq->q.fragments_tail = skb;
185 if (prev)
186 prev->next = skb;
187 else
188 fq->q.fragments = skb;
189
190 ldev = skb->dev;
191 if (ldev)
192 skb->dev = NULL;
193
194 fq->q.stamp = skb->tstamp;
195 if (frag_type == LOWPAN_DISPATCH_FRAG1)
196 fq->q.flags |= INET_FRAG_FIRST_IN;
197
198 fq->q.meat += skb->len;
199 add_frag_mem_limit(fq->q.net, skb->truesize);
200
201 if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
202 fq->q.meat == fq->q.len) {
203 int res;
204 unsigned long orefdst = skb->_skb_refdst;
205
206 skb->_skb_refdst = 0UL;
207 res = lowpan_frag_reasm(fq, prev, ldev);
208 skb->_skb_refdst = orefdst;
209 return res;
210 }
211
212 return -1;
213 err:
214 kfree_skb(skb);
215 return -1;
216 }
217
218 /* Check if this packet is complete.
219 * Returns NULL on failure by any reason, and pointer
220 * to current nexthdr field in reassembled frame.
221 *
222 * It is called with locked fq, and caller must check that
223 * queue is eligible for reassembly i.e. it is not COMPLETE,
224 * the last and the first frames arrived and all the bits are here.
225 */
226 static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *prev,
227 struct net_device *ldev)
228 {
229 struct sk_buff *fp, *head = fq->q.fragments;
230 int sum_truesize;
231
232 inet_frag_kill(&fq->q, &lowpan_frags);
233
234 /* Make the one we just received the head. */
235 if (prev) {
236 head = prev->next;
237 fp = skb_clone(head, GFP_ATOMIC);
238
239 if (!fp)
240 goto out_oom;
241
242 fp->next = head->next;
243 if (!fp->next)
244 fq->q.fragments_tail = fp;
245 prev->next = fp;
246
247 skb_morph(head, fq->q.fragments);
248 head->next = fq->q.fragments->next;
249
250 consume_skb(fq->q.fragments);
251 fq->q.fragments = head;
252 }
253
254 /* Head of list must not be cloned. */
255 if (skb_unclone(head, GFP_ATOMIC))
256 goto out_oom;
257
258 /* If the first fragment is fragmented itself, we split
259 * it to two chunks: the first with data and paged part
260 * and the second, holding only fragments.
261 */
262 if (skb_has_frag_list(head)) {
263 struct sk_buff *clone;
264 int i, plen = 0;
265
266 clone = alloc_skb(0, GFP_ATOMIC);
267 if (!clone)
268 goto out_oom;
269 clone->next = head->next;
270 head->next = clone;
271 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
272 skb_frag_list_init(head);
273 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
274 plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
275 clone->len = head->data_len - plen;
276 clone->data_len = clone->len;
277 head->data_len -= clone->len;
278 head->len -= clone->len;
279 add_frag_mem_limit(fq->q.net, clone->truesize);
280 }
281
282 WARN_ON(head == NULL);
283
284 sum_truesize = head->truesize;
285 for (fp = head->next; fp;) {
286 bool headstolen;
287 int delta;
288 struct sk_buff *next = fp->next;
289
290 sum_truesize += fp->truesize;
291 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
292 kfree_skb_partial(fp, headstolen);
293 } else {
294 if (!skb_shinfo(head)->frag_list)
295 skb_shinfo(head)->frag_list = fp;
296 head->data_len += fp->len;
297 head->len += fp->len;
298 head->truesize += fp->truesize;
299 }
300 fp = next;
301 }
302 sub_frag_mem_limit(fq->q.net, sum_truesize);
303
304 head->next = NULL;
305 head->dev = ldev;
306 head->tstamp = fq->q.stamp;
307
308 fq->q.fragments = NULL;
309 fq->q.fragments_tail = NULL;
310
311 return 1;
312 out_oom:
313 net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
314 return -1;
315 }
316
317 static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
318 lowpan_rx_result res)
319 {
320 switch (res) {
321 case RX_QUEUED:
322 return NET_RX_SUCCESS;
323 case RX_CONTINUE:
324 /* nobody cared about this packet */
325 net_warn_ratelimited("%s: received unknown dispatch\n",
326 __func__);
327
328 /* fall-through */
329 default:
330 /* all others failure */
331 return NET_RX_DROP;
332 }
333 }
334
335 static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
336 {
337 int ret;
338
339 if (!lowpan_is_iphc(*skb_network_header(skb)))
340 return RX_CONTINUE;
341
342 ret = lowpan_iphc_decompress(skb);
343 if (ret < 0)
344 return RX_DROP;
345
346 return RX_QUEUED;
347 }
348
349 static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
350 {
351 lowpan_rx_result res;
352
353 #define CALL_RXH(rxh) \
354 do { \
355 res = rxh(skb); \
356 if (res != RX_CONTINUE) \
357 goto rxh_next; \
358 } while (0)
359
360 /* likely at first */
361 CALL_RXH(lowpan_frag_rx_h_iphc);
362 CALL_RXH(lowpan_rx_h_ipv6);
363
364 rxh_next:
365 return lowpan_frag_rx_handlers_result(skb, res);
366 #undef CALL_RXH
367 }
368
369 #define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
370 #define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
371
372 static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
373 struct lowpan_802154_cb *cb)
374 {
375 bool fail;
376 u8 high = 0, low = 0;
377 __be16 d_tag = 0;
378
379 fail = lowpan_fetch_skb(skb, &high, 1);
380 fail |= lowpan_fetch_skb(skb, &low, 1);
381 /* remove the dispatch value and use first three bits as high value
382 * for the datagram size
383 */
384 cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
385 LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
386 fail |= lowpan_fetch_skb(skb, &d_tag, 2);
387 cb->d_tag = ntohs(d_tag);
388
389 if (frag_type == LOWPAN_DISPATCH_FRAGN) {
390 fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
391 } else {
392 skb_reset_network_header(skb);
393 cb->d_offset = 0;
394 /* check if datagram_size has ipv6hdr on FRAG1 */
395 fail |= cb->d_size < sizeof(struct ipv6hdr);
396 /* check if we can dereference the dispatch value */
397 fail |= !skb->len;
398 }
399
400 if (unlikely(fail))
401 return -EIO;
402
403 return 0;
404 }
405
406 int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
407 {
408 struct lowpan_frag_queue *fq;
409 struct net *net = dev_net(skb->dev);
410 struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
411 struct ieee802154_hdr hdr;
412 int err;
413
414 if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
415 goto err;
416
417 err = lowpan_get_cb(skb, frag_type, cb);
418 if (err < 0)
419 goto err;
420
421 if (frag_type == LOWPAN_DISPATCH_FRAG1) {
422 err = lowpan_invoke_frag_rx_handlers(skb);
423 if (err == NET_RX_DROP)
424 goto err;
425 }
426
427 if (cb->d_size > IPV6_MIN_MTU) {
428 net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
429 goto err;
430 }
431
432 fq = fq_find(net, cb, &hdr.source, &hdr.dest);
433 if (fq != NULL) {
434 int ret;
435
436 spin_lock(&fq->q.lock);
437 ret = lowpan_frag_queue(fq, skb, frag_type);
438 spin_unlock(&fq->q.lock);
439
440 inet_frag_put(&fq->q, &lowpan_frags);
441 return ret;
442 }
443
444 err:
445 kfree_skb(skb);
446 return -1;
447 }
448
449 #ifdef CONFIG_SYSCTL
450 static int zero;
451
452 static struct ctl_table lowpan_frags_ns_ctl_table[] = {
453 {
454 .procname = "6lowpanfrag_high_thresh",
455 .data = &init_net.ieee802154_lowpan.frags.high_thresh,
456 .maxlen = sizeof(int),
457 .mode = 0644,
458 .proc_handler = proc_dointvec_minmax,
459 .extra1 = &init_net.ieee802154_lowpan.frags.low_thresh
460 },
461 {
462 .procname = "6lowpanfrag_low_thresh",
463 .data = &init_net.ieee802154_lowpan.frags.low_thresh,
464 .maxlen = sizeof(int),
465 .mode = 0644,
466 .proc_handler = proc_dointvec_minmax,
467 .extra1 = &zero,
468 .extra2 = &init_net.ieee802154_lowpan.frags.high_thresh
469 },
470 {
471 .procname = "6lowpanfrag_time",
472 .data = &init_net.ieee802154_lowpan.frags.timeout,
473 .maxlen = sizeof(int),
474 .mode = 0644,
475 .proc_handler = proc_dointvec_jiffies,
476 },
477 { }
478 };
479
480 /* secret interval has been deprecated */
481 static int lowpan_frags_secret_interval_unused;
482 static struct ctl_table lowpan_frags_ctl_table[] = {
483 {
484 .procname = "6lowpanfrag_secret_interval",
485 .data = &lowpan_frags_secret_interval_unused,
486 .maxlen = sizeof(int),
487 .mode = 0644,
488 .proc_handler = proc_dointvec_jiffies,
489 },
490 { }
491 };
492
493 static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
494 {
495 struct ctl_table *table;
496 struct ctl_table_header *hdr;
497 struct netns_ieee802154_lowpan *ieee802154_lowpan =
498 net_ieee802154_lowpan(net);
499
500 table = lowpan_frags_ns_ctl_table;
501 if (!net_eq(net, &init_net)) {
502 table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
503 GFP_KERNEL);
504 if (table == NULL)
505 goto err_alloc;
506
507 table[0].data = &ieee802154_lowpan->frags.high_thresh;
508 table[0].extra1 = &ieee802154_lowpan->frags.low_thresh;
509 table[0].extra2 = &init_net.ieee802154_lowpan.frags.high_thresh;
510 table[1].data = &ieee802154_lowpan->frags.low_thresh;
511 table[1].extra2 = &ieee802154_lowpan->frags.high_thresh;
512 table[2].data = &ieee802154_lowpan->frags.timeout;
513
514 /* Don't export sysctls to unprivileged users */
515 if (net->user_ns != &init_user_ns)
516 table[0].procname = NULL;
517 }
518
519 hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
520 if (hdr == NULL)
521 goto err_reg;
522
523 ieee802154_lowpan->sysctl.frags_hdr = hdr;
524 return 0;
525
526 err_reg:
527 if (!net_eq(net, &init_net))
528 kfree(table);
529 err_alloc:
530 return -ENOMEM;
531 }
532
533 static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
534 {
535 struct ctl_table *table;
536 struct netns_ieee802154_lowpan *ieee802154_lowpan =
537 net_ieee802154_lowpan(net);
538
539 table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
540 unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
541 if (!net_eq(net, &init_net))
542 kfree(table);
543 }
544
545 static struct ctl_table_header *lowpan_ctl_header;
546
547 static int __init lowpan_frags_sysctl_register(void)
548 {
549 lowpan_ctl_header = register_net_sysctl(&init_net,
550 "net/ieee802154/6lowpan",
551 lowpan_frags_ctl_table);
552 return lowpan_ctl_header == NULL ? -ENOMEM : 0;
553 }
554
555 static void lowpan_frags_sysctl_unregister(void)
556 {
557 unregister_net_sysctl_table(lowpan_ctl_header);
558 }
559 #else
560 static inline int lowpan_frags_ns_sysctl_register(struct net *net)
561 {
562 return 0;
563 }
564
565 static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
566 {
567 }
568
569 static inline int __init lowpan_frags_sysctl_register(void)
570 {
571 return 0;
572 }
573
574 static inline void lowpan_frags_sysctl_unregister(void)
575 {
576 }
577 #endif
578
579 static int __net_init lowpan_frags_init_net(struct net *net)
580 {
581 struct netns_ieee802154_lowpan *ieee802154_lowpan =
582 net_ieee802154_lowpan(net);
583 int res;
584
585 ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
586 ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
587 ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;
588
589 res = inet_frags_init_net(&ieee802154_lowpan->frags);
590 if (res)
591 return res;
592 res = lowpan_frags_ns_sysctl_register(net);
593 if (res)
594 inet_frags_uninit_net(&ieee802154_lowpan->frags);
595 return res;
596 }
597
598 static void __net_exit lowpan_frags_exit_net(struct net *net)
599 {
600 struct netns_ieee802154_lowpan *ieee802154_lowpan =
601 net_ieee802154_lowpan(net);
602
603 lowpan_frags_ns_sysctl_unregister(net);
604 inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags);
605 }
606
607 static struct pernet_operations lowpan_frags_ops = {
608 .init = lowpan_frags_init_net,
609 .exit = lowpan_frags_exit_net,
610 };
611
612 int __init lowpan_net_frag_init(void)
613 {
614 int ret;
615
616 ret = lowpan_frags_sysctl_register();
617 if (ret)
618 return ret;
619
620 ret = register_pernet_subsys(&lowpan_frags_ops);
621 if (ret)
622 goto err_pernet;
623
624 lowpan_frags.hashfn = lowpan_hashfn;
625 lowpan_frags.constructor = lowpan_frag_init;
626 lowpan_frags.destructor = NULL;
627 lowpan_frags.skb_free = NULL;
628 lowpan_frags.qsize = sizeof(struct frag_queue);
629 lowpan_frags.match = lowpan_frag_match;
630 lowpan_frags.frag_expire = lowpan_frag_expire;
631 lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
632 ret = inet_frags_init(&lowpan_frags);
633 if (ret)
634 goto err_pernet;
635
636 return ret;
637 err_pernet:
638 lowpan_frags_sysctl_unregister();
639 return ret;
640 }
641
642 void lowpan_net_frag_exit(void)
643 {
644 inet_frags_fini(&lowpan_frags);
645 lowpan_frags_sysctl_unregister();
646 unregister_pernet_subsys(&lowpan_frags_ops);
647 }
Linux with added FPC-III support