This source file includes following definitions.
- lowpan_frag_init
- lowpan_frag_expire
- fq_find
- lowpan_frag_queue
- lowpan_frag_reasm
- lowpan_frag_rx_handlers_result
- lowpan_frag_rx_h_iphc
- lowpan_invoke_frag_rx_handlers
- lowpan_get_cb
- lowpan_frag_rcv
- lowpan_frags_ns_sysctl_register
- lowpan_frags_ns_sysctl_unregister
- lowpan_frags_sysctl_register
- lowpan_frags_sysctl_unregister
- lowpan_frags_ns_sysctl_register
- lowpan_frags_ns_sysctl_unregister
- lowpan_frags_sysctl_register
- lowpan_frags_sysctl_unregister
- lowpan_frags_init_net
- lowpan_frags_pre_exit_net
- lowpan_frags_exit_net
- lowpan_key_hashfn
- lowpan_obj_hashfn
- lowpan_obj_cmpfn
- lowpan_net_frag_init
- lowpan_net_frag_exit
1
2
3
4
5
6
7
8
9
10 #define pr_fmt(fmt) "6LoWPAN: " fmt
11
12 #include <linux/net.h>
13 #include <linux/list.h>
14 #include <linux/netdevice.h>
15 #include <linux/random.h>
16 #include <linux/jhash.h>
17 #include <linux/skbuff.h>
18 #include <linux/slab.h>
19 #include <linux/export.h>
20
21 #include <net/ieee802154_netdev.h>
22 #include <net/6lowpan.h>
23 #include <net/ipv6_frag.h>
24 #include <net/inet_frag.h>
25 #include <net/ip.h>
26
27 #include "6lowpan_i.h"
28
29 static const char lowpan_frags_cache_name[] = "lowpan-frags";
30
31 static struct inet_frags lowpan_frags;
32
33 static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb,
34 struct sk_buff *prev, struct net_device *ldev);
35
36 static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
37 {
38 const struct frag_lowpan_compare_key *key = a;
39
40 BUILD_BUG_ON(sizeof(*key) > sizeof(q->key));
41 memcpy(&q->key, key, sizeof(*key));
42 }
43
44 static void lowpan_frag_expire(struct timer_list *t)
45 {
46 struct inet_frag_queue *frag = from_timer(frag, t, timer);
47 struct frag_queue *fq;
48
49 fq = container_of(frag, struct frag_queue, q);
50
51 spin_lock(&fq->q.lock);
52
53 if (fq->q.flags & INET_FRAG_COMPLETE)
54 goto out;
55
56 inet_frag_kill(&fq->q);
57 out:
58 spin_unlock(&fq->q.lock);
59 inet_frag_put(&fq->q);
60 }
61
62 static inline struct lowpan_frag_queue *
63 fq_find(struct net *net, const struct lowpan_802154_cb *cb,
64 const struct ieee802154_addr *src,
65 const struct ieee802154_addr *dst)
66 {
67 struct netns_ieee802154_lowpan *ieee802154_lowpan =
68 net_ieee802154_lowpan(net);
69 struct frag_lowpan_compare_key key = {};
70 struct inet_frag_queue *q;
71
72 key.tag = cb->d_tag;
73 key.d_size = cb->d_size;
74 key.src = *src;
75 key.dst = *dst;
76
77 q = inet_frag_find(ieee802154_lowpan->fqdir, &key);
78 if (!q)
79 return NULL;
80
81 return container_of(q, struct lowpan_frag_queue, q);
82 }
83
84 static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
85 struct sk_buff *skb, u8 frag_type)
86 {
87 struct sk_buff *prev_tail;
88 struct net_device *ldev;
89 int end, offset, err;
90
91
92
93
94 BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet_skb_parm));
95 BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet6_skb_parm));
96
97 if (fq->q.flags & INET_FRAG_COMPLETE)
98 goto err;
99
100 offset = lowpan_802154_cb(skb)->d_offset << 3;
101 end = lowpan_802154_cb(skb)->d_size;
102
103
104 if (offset + skb->len == end) {
105
106
107
108 if (end < fq->q.len ||
109 ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
110 goto err;
111 fq->q.flags |= INET_FRAG_LAST_IN;
112 fq->q.len = end;
113 } else {
114 if (end > fq->q.len) {
115
116 if (fq->q.flags & INET_FRAG_LAST_IN)
117 goto err;
118 fq->q.len = end;
119 }
120 }
121
122 ldev = skb->dev;
123 if (ldev)
124 skb->dev = NULL;
125 barrier();
126
127 prev_tail = fq->q.fragments_tail;
128 err = inet_frag_queue_insert(&fq->q, skb, offset, end);
129 if (err)
130 goto err;
131
132 fq->q.stamp = skb->tstamp;
133 if (frag_type == LOWPAN_DISPATCH_FRAG1)
134 fq->q.flags |= INET_FRAG_FIRST_IN;
135
136 fq->q.meat += skb->len;
137 add_frag_mem_limit(fq->q.fqdir, skb->truesize);
138
139 if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
140 fq->q.meat == fq->q.len) {
141 int res;
142 unsigned long orefdst = skb->_skb_refdst;
143
144 skb->_skb_refdst = 0UL;
145 res = lowpan_frag_reasm(fq, skb, prev_tail, ldev);
146 skb->_skb_refdst = orefdst;
147 return res;
148 }
149 skb_dst_drop(skb);
150
151 return -1;
152 err:
153 kfree_skb(skb);
154 return -1;
155 }
156
157
158
159
160
161
162
163 static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb,
164 struct sk_buff *prev_tail, struct net_device *ldev)
165 {
166 void *reasm_data;
167
168 inet_frag_kill(&fq->q);
169
170 reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
171 if (!reasm_data)
172 goto out_oom;
173 inet_frag_reasm_finish(&fq->q, skb, reasm_data, false);
174
175 skb->dev = ldev;
176 skb->tstamp = fq->q.stamp;
177 fq->q.rb_fragments = RB_ROOT;
178 fq->q.fragments_tail = NULL;
179 fq->q.last_run_head = NULL;
180
181 return 1;
182 out_oom:
183 net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
184 return -1;
185 }
186
187 static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
188 lowpan_rx_result res)
189 {
190 switch (res) {
191 case RX_QUEUED:
192 return NET_RX_SUCCESS;
193 case RX_CONTINUE:
194
195 net_warn_ratelimited("%s: received unknown dispatch\n",
196 __func__);
197
198
199 default:
200
201 return NET_RX_DROP;
202 }
203 }
204
205 static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
206 {
207 int ret;
208
209 if (!lowpan_is_iphc(*skb_network_header(skb)))
210 return RX_CONTINUE;
211
212 ret = lowpan_iphc_decompress(skb);
213 if (ret < 0)
214 return RX_DROP;
215
216 return RX_QUEUED;
217 }
218
219 static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
220 {
221 lowpan_rx_result res;
222
223 #define CALL_RXH(rxh) \
224 do { \
225 res = rxh(skb); \
226 if (res != RX_CONTINUE) \
227 goto rxh_next; \
228 } while (0)
229
230
231 CALL_RXH(lowpan_frag_rx_h_iphc);
232 CALL_RXH(lowpan_rx_h_ipv6);
233
234 rxh_next:
235 return lowpan_frag_rx_handlers_result(skb, res);
236 #undef CALL_RXH
237 }
238
239 #define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
240 #define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
241
242 static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
243 struct lowpan_802154_cb *cb)
244 {
245 bool fail;
246 u8 high = 0, low = 0;
247 __be16 d_tag = 0;
248
249 fail = lowpan_fetch_skb(skb, &high, 1);
250 fail |= lowpan_fetch_skb(skb, &low, 1);
251
252
253
254 cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
255 LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
256 fail |= lowpan_fetch_skb(skb, &d_tag, 2);
257 cb->d_tag = ntohs(d_tag);
258
259 if (frag_type == LOWPAN_DISPATCH_FRAGN) {
260 fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
261 } else {
262 skb_reset_network_header(skb);
263 cb->d_offset = 0;
264
265 fail |= cb->d_size < sizeof(struct ipv6hdr);
266
267 fail |= !skb->len;
268 }
269
270 if (unlikely(fail))
271 return -EIO;
272
273 return 0;
274 }
275
276 int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
277 {
278 struct lowpan_frag_queue *fq;
279 struct net *net = dev_net(skb->dev);
280 struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
281 struct ieee802154_hdr hdr = {};
282 int err;
283
284 if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
285 goto err;
286
287 err = lowpan_get_cb(skb, frag_type, cb);
288 if (err < 0)
289 goto err;
290
291 if (frag_type == LOWPAN_DISPATCH_FRAG1) {
292 err = lowpan_invoke_frag_rx_handlers(skb);
293 if (err == NET_RX_DROP)
294 goto err;
295 }
296
297 if (cb->d_size > IPV6_MIN_MTU) {
298 net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
299 goto err;
300 }
301
302 fq = fq_find(net, cb, &hdr.source, &hdr.dest);
303 if (fq != NULL) {
304 int ret;
305
306 spin_lock(&fq->q.lock);
307 ret = lowpan_frag_queue(fq, skb, frag_type);
308 spin_unlock(&fq->q.lock);
309
310 inet_frag_put(&fq->q);
311 return ret;
312 }
313
314 err:
315 kfree_skb(skb);
316 return -1;
317 }
318
319 #ifdef CONFIG_SYSCTL
320
321 static struct ctl_table lowpan_frags_ns_ctl_table[] = {
322 {
323 .procname = "6lowpanfrag_high_thresh",
324 .maxlen = sizeof(unsigned long),
325 .mode = 0644,
326 .proc_handler = proc_doulongvec_minmax,
327 },
328 {
329 .procname = "6lowpanfrag_low_thresh",
330 .maxlen = sizeof(unsigned long),
331 .mode = 0644,
332 .proc_handler = proc_doulongvec_minmax,
333 },
334 {
335 .procname = "6lowpanfrag_time",
336 .maxlen = sizeof(int),
337 .mode = 0644,
338 .proc_handler = proc_dointvec_jiffies,
339 },
340 { }
341 };
342
343
344 static int lowpan_frags_secret_interval_unused;
345 static struct ctl_table lowpan_frags_ctl_table[] = {
346 {
347 .procname = "6lowpanfrag_secret_interval",
348 .data = &lowpan_frags_secret_interval_unused,
349 .maxlen = sizeof(int),
350 .mode = 0644,
351 .proc_handler = proc_dointvec_jiffies,
352 },
353 { }
354 };
355
356 static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
357 {
358 struct ctl_table *table;
359 struct ctl_table_header *hdr;
360 struct netns_ieee802154_lowpan *ieee802154_lowpan =
361 net_ieee802154_lowpan(net);
362
363 table = lowpan_frags_ns_ctl_table;
364 if (!net_eq(net, &init_net)) {
365 table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
366 GFP_KERNEL);
367 if (table == NULL)
368 goto err_alloc;
369
370
371 if (net->user_ns != &init_user_ns)
372 table[0].procname = NULL;
373 }
374
375 table[0].data = &ieee802154_lowpan->fqdir->high_thresh;
376 table[0].extra1 = &ieee802154_lowpan->fqdir->low_thresh;
377 table[1].data = &ieee802154_lowpan->fqdir->low_thresh;
378 table[1].extra2 = &ieee802154_lowpan->fqdir->high_thresh;
379 table[2].data = &ieee802154_lowpan->fqdir->timeout;
380
381 hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
382 if (hdr == NULL)
383 goto err_reg;
384
385 ieee802154_lowpan->sysctl.frags_hdr = hdr;
386 return 0;
387
388 err_reg:
389 if (!net_eq(net, &init_net))
390 kfree(table);
391 err_alloc:
392 return -ENOMEM;
393 }
394
395 static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
396 {
397 struct ctl_table *table;
398 struct netns_ieee802154_lowpan *ieee802154_lowpan =
399 net_ieee802154_lowpan(net);
400
401 table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
402 unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
403 if (!net_eq(net, &init_net))
404 kfree(table);
405 }
406
407 static struct ctl_table_header *lowpan_ctl_header;
408
409 static int __init lowpan_frags_sysctl_register(void)
410 {
411 lowpan_ctl_header = register_net_sysctl(&init_net,
412 "net/ieee802154/6lowpan",
413 lowpan_frags_ctl_table);
414 return lowpan_ctl_header == NULL ? -ENOMEM : 0;
415 }
416
417 static void lowpan_frags_sysctl_unregister(void)
418 {
419 unregister_net_sysctl_table(lowpan_ctl_header);
420 }
421 #else
422 static inline int lowpan_frags_ns_sysctl_register(struct net *net)
423 {
424 return 0;
425 }
426
427 static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
428 {
429 }
430
431 static inline int __init lowpan_frags_sysctl_register(void)
432 {
433 return 0;
434 }
435
436 static inline void lowpan_frags_sysctl_unregister(void)
437 {
438 }
439 #endif
440
441 static int __net_init lowpan_frags_init_net(struct net *net)
442 {
443 struct netns_ieee802154_lowpan *ieee802154_lowpan =
444 net_ieee802154_lowpan(net);
445 int res;
446
447
448 res = fqdir_init(&ieee802154_lowpan->fqdir, &lowpan_frags, net);
449 if (res < 0)
450 return res;
451
452 ieee802154_lowpan->fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
453 ieee802154_lowpan->fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
454 ieee802154_lowpan->fqdir->timeout = IPV6_FRAG_TIMEOUT;
455
456 res = lowpan_frags_ns_sysctl_register(net);
457 if (res < 0)
458 fqdir_exit(ieee802154_lowpan->fqdir);
459 return res;
460 }
461
462 static void __net_exit lowpan_frags_pre_exit_net(struct net *net)
463 {
464 struct netns_ieee802154_lowpan *ieee802154_lowpan =
465 net_ieee802154_lowpan(net);
466
467 fqdir_pre_exit(ieee802154_lowpan->fqdir);
468 }
469
470 static void __net_exit lowpan_frags_exit_net(struct net *net)
471 {
472 struct netns_ieee802154_lowpan *ieee802154_lowpan =
473 net_ieee802154_lowpan(net);
474
475 lowpan_frags_ns_sysctl_unregister(net);
476 fqdir_exit(ieee802154_lowpan->fqdir);
477 }
478
479 static struct pernet_operations lowpan_frags_ops = {
480 .init = lowpan_frags_init_net,
481 .pre_exit = lowpan_frags_pre_exit_net,
482 .exit = lowpan_frags_exit_net,
483 };
484
485 static u32 lowpan_key_hashfn(const void *data, u32 len, u32 seed)
486 {
487 return jhash2(data,
488 sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
489 }
490
491 static u32 lowpan_obj_hashfn(const void *data, u32 len, u32 seed)
492 {
493 const struct inet_frag_queue *fq = data;
494
495 return jhash2((const u32 *)&fq->key,
496 sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
497 }
498
499 static int lowpan_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
500 {
501 const struct frag_lowpan_compare_key *key = arg->key;
502 const struct inet_frag_queue *fq = ptr;
503
504 return !!memcmp(&fq->key, key, sizeof(*key));
505 }
506
507 static const struct rhashtable_params lowpan_rhash_params = {
508 .head_offset = offsetof(struct inet_frag_queue, node),
509 .hashfn = lowpan_key_hashfn,
510 .obj_hashfn = lowpan_obj_hashfn,
511 .obj_cmpfn = lowpan_obj_cmpfn,
512 .automatic_shrinking = true,
513 };
514
515 int __init lowpan_net_frag_init(void)
516 {
517 int ret;
518
519 lowpan_frags.constructor = lowpan_frag_init;
520 lowpan_frags.destructor = NULL;
521 lowpan_frags.qsize = sizeof(struct frag_queue);
522 lowpan_frags.frag_expire = lowpan_frag_expire;
523 lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
524 lowpan_frags.rhash_params = lowpan_rhash_params;
525 ret = inet_frags_init(&lowpan_frags);
526 if (ret)
527 goto out;
528
529 ret = lowpan_frags_sysctl_register();
530 if (ret)
531 goto err_sysctl;
532
533 ret = register_pernet_subsys(&lowpan_frags_ops);
534 if (ret)
535 goto err_pernet;
536 out:
537 return ret;
538 err_pernet:
539 lowpan_frags_sysctl_unregister();
540 err_sysctl:
541 inet_frags_fini(&lowpan_frags);
542 return ret;
543 }
544
545 void lowpan_net_frag_exit(void)
546 {
547 lowpan_frags_sysctl_unregister();
548 unregister_pernet_subsys(&lowpan_frags_ops);
549 inet_frags_fini(&lowpan_frags);
550 }