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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Stream Parser
4 *
5 * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
6 */
7
8#include <linux/bpf.h>
9#include <linux/errno.h>
10#include <linux/errqueue.h>
11#include <linux/file.h>
12#include <linux/in.h>
13#include <linux/kernel.h>
14#include <linux/export.h>
15#include <linux/init.h>
16#include <linux/net.h>
17#include <linux/netdevice.h>
18#include <linux/poll.h>
19#include <linux/rculist.h>
20#include <linux/skbuff.h>
21#include <linux/socket.h>
22#include <linux/uaccess.h>
23#include <linux/workqueue.h>
24#include <net/strparser.h>
25#include <net/netns/generic.h>
26#include <net/sock.h>
27
28static struct workqueue_struct *strp_wq;
29
30static inline struct _strp_msg *_strp_msg(struct sk_buff *skb)
31{
32 return (struct _strp_msg *)((void *)skb->cb +
33 offsetof(struct sk_skb_cb, strp));
34}
35
36/* Lower lock held */
37static void strp_abort_strp(struct strparser *strp, int err)
38{
39 /* Unrecoverable error in receive */
40
41 cancel_delayed_work(&strp->msg_timer_work);
42
43 if (strp->stopped)
44 return;
45
46 strp->stopped = 1;
47
48 if (strp->sk) {
49 struct sock *sk = strp->sk;
50
51 /* Report an error on the lower socket */
52 sk->sk_err = -err;
53 sk_error_report(sk);
54 }
55}
56
57static void strp_start_timer(struct strparser *strp, long timeo)
58{
59 if (timeo && timeo != LONG_MAX)
60 mod_delayed_work(strp_wq, &strp->msg_timer_work, timeo);
61}
62
63/* Lower lock held */
64static void strp_parser_err(struct strparser *strp, int err,
65 read_descriptor_t *desc)
66{
67 desc->error = err;
68 kfree_skb(strp->skb_head);
69 strp->skb_head = NULL;
70 strp->cb.abort_parser(strp, err);
71}
72
73static inline int strp_peek_len(struct strparser *strp)
74{
75 if (strp->sk) {
76 struct socket *sock = strp->sk->sk_socket;
77
78 return sock->ops->peek_len(sock);
79 }
80
81 /* If we don't have an associated socket there's nothing to peek.
82 * Return int max to avoid stopping the strparser.
83 */
84
85 return INT_MAX;
86}
87
88/* Lower socket lock held */
89static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
90 unsigned int orig_offset, size_t orig_len,
91 size_t max_msg_size, long timeo)
92{
93 struct strparser *strp = (struct strparser *)desc->arg.data;
94 struct _strp_msg *stm;
95 struct sk_buff *head, *skb;
96 size_t eaten = 0, cand_len;
97 ssize_t extra;
98 int err;
99 bool cloned_orig = false;
100
101 if (strp->paused)
102 return 0;
103
104 head = strp->skb_head;
105 if (head) {
106 /* Message already in progress */
107 if (unlikely(orig_offset)) {
108 /* Getting data with a non-zero offset when a message is
109 * in progress is not expected. If it does happen, we
110 * need to clone and pull since we can't deal with
111 * offsets in the skbs for a message expect in the head.
112 */
113 orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
114 if (!orig_skb) {
115 STRP_STATS_INCR(strp->stats.mem_fail);
116 desc->error = -ENOMEM;
117 return 0;
118 }
119 if (!pskb_pull(orig_skb, orig_offset)) {
120 STRP_STATS_INCR(strp->stats.mem_fail);
121 kfree_skb(orig_skb);
122 desc->error = -ENOMEM;
123 return 0;
124 }
125 cloned_orig = true;
126 orig_offset = 0;
127 }
128
129 if (!strp->skb_nextp) {
130 /* We are going to append to the frags_list of head.
131 * Need to unshare the frag_list.
132 */
133 err = skb_unclone(head, GFP_ATOMIC);
134 if (err) {
135 STRP_STATS_INCR(strp->stats.mem_fail);
136 desc->error = err;
137 return 0;
138 }
139
140 if (unlikely(skb_shinfo(head)->frag_list)) {
141 /* We can't append to an sk_buff that already
142 * has a frag_list. We create a new head, point
143 * the frag_list of that to the old head, and
144 * then are able to use the old head->next for
145 * appending to the message.
146 */
147 if (WARN_ON(head->next)) {
148 desc->error = -EINVAL;
149 return 0;
150 }
151
152 skb = alloc_skb_for_msg(head);
153 if (!skb) {
154 STRP_STATS_INCR(strp->stats.mem_fail);
155 desc->error = -ENOMEM;
156 return 0;
157 }
158
159 strp->skb_nextp = &head->next;
160 strp->skb_head = skb;
161 head = skb;
162 } else {
163 strp->skb_nextp =
164 &skb_shinfo(head)->frag_list;
165 }
166 }
167 }
168
169 while (eaten < orig_len) {
170 /* Always clone since we will consume something */
171 skb = skb_clone(orig_skb, GFP_ATOMIC);
172 if (!skb) {
173 STRP_STATS_INCR(strp->stats.mem_fail);
174 desc->error = -ENOMEM;
175 break;
176 }
177
178 cand_len = orig_len - eaten;
179
180 head = strp->skb_head;
181 if (!head) {
182 head = skb;
183 strp->skb_head = head;
184 /* Will set skb_nextp on next packet if needed */
185 strp->skb_nextp = NULL;
186 stm = _strp_msg(head);
187 memset(stm, 0, sizeof(*stm));
188 stm->strp.offset = orig_offset + eaten;
189 } else {
190 /* Unclone if we are appending to an skb that we
191 * already share a frag_list with.
192 */
193 if (skb_has_frag_list(skb)) {
194 err = skb_unclone(skb, GFP_ATOMIC);
195 if (err) {
196 STRP_STATS_INCR(strp->stats.mem_fail);
197 desc->error = err;
198 break;
199 }
200 }
201
202 stm = _strp_msg(head);
203 *strp->skb_nextp = skb;
204 strp->skb_nextp = &skb->next;
205 head->data_len += skb->len;
206 head->len += skb->len;
207 head->truesize += skb->truesize;
208 }
209
210 if (!stm->strp.full_len) {
211 ssize_t len;
212
213 len = (*strp->cb.parse_msg)(strp, head);
214
215 if (!len) {
216 /* Need more header to determine length */
217 if (!stm->accum_len) {
218 /* Start RX timer for new message */
219 strp_start_timer(strp, timeo);
220 }
221 stm->accum_len += cand_len;
222 eaten += cand_len;
223 STRP_STATS_INCR(strp->stats.need_more_hdr);
224 WARN_ON(eaten != orig_len);
225 break;
226 } else if (len < 0) {
227 if (len == -ESTRPIPE && stm->accum_len) {
228 len = -ENODATA;
229 strp->unrecov_intr = 1;
230 } else {
231 strp->interrupted = 1;
232 }
233 strp_parser_err(strp, len, desc);
234 break;
235 } else if (len > max_msg_size) {
236 /* Message length exceeds maximum allowed */
237 STRP_STATS_INCR(strp->stats.msg_too_big);
238 strp_parser_err(strp, -EMSGSIZE, desc);
239 break;
240 } else if (len <= (ssize_t)head->len -
241 skb->len - stm->strp.offset) {
242 /* Length must be into new skb (and also
243 * greater than zero)
244 */
245 STRP_STATS_INCR(strp->stats.bad_hdr_len);
246 strp_parser_err(strp, -EPROTO, desc);
247 break;
248 }
249
250 stm->strp.full_len = len;
251 }
252
253 extra = (ssize_t)(stm->accum_len + cand_len) -
254 stm->strp.full_len;
255
256 if (extra < 0) {
257 /* Message not complete yet. */
258 if (stm->strp.full_len - stm->accum_len >
259 strp_peek_len(strp)) {
260 /* Don't have the whole message in the socket
261 * buffer. Set strp->need_bytes to wait for
262 * the rest of the message. Also, set "early
263 * eaten" since we've already buffered the skb
264 * but don't consume yet per strp_read_sock.
265 */
266
267 if (!stm->accum_len) {
268 /* Start RX timer for new message */
269 strp_start_timer(strp, timeo);
270 }
271
272 stm->accum_len += cand_len;
273 eaten += cand_len;
274 strp->need_bytes = stm->strp.full_len -
275 stm->accum_len;
276 STRP_STATS_ADD(strp->stats.bytes, cand_len);
277 desc->count = 0; /* Stop reading socket */
278 break;
279 }
280 stm->accum_len += cand_len;
281 eaten += cand_len;
282 WARN_ON(eaten != orig_len);
283 break;
284 }
285
286 /* Positive extra indicates more bytes than needed for the
287 * message
288 */
289
290 WARN_ON(extra > cand_len);
291
292 eaten += (cand_len - extra);
293
294 /* Hurray, we have a new message! */
295 cancel_delayed_work(&strp->msg_timer_work);
296 strp->skb_head = NULL;
297 strp->need_bytes = 0;
298 STRP_STATS_INCR(strp->stats.msgs);
299
300 /* Give skb to upper layer */
301 strp->cb.rcv_msg(strp, head);
302
303 if (unlikely(strp->paused)) {
304 /* Upper layer paused strp */
305 break;
306 }
307 }
308
309 if (cloned_orig)
310 kfree_skb(orig_skb);
311
312 STRP_STATS_ADD(strp->stats.bytes, eaten);
313
314 return eaten;
315}
316
317int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
318 unsigned int orig_offset, size_t orig_len,
319 size_t max_msg_size, long timeo)
320{
321 read_descriptor_t desc; /* Dummy arg to strp_recv */
322
323 desc.arg.data = strp;
324
325 return __strp_recv(&desc, orig_skb, orig_offset, orig_len,
326 max_msg_size, timeo);
327}
328EXPORT_SYMBOL_GPL(strp_process);
329
330static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
331 unsigned int orig_offset, size_t orig_len)
332{
333 struct strparser *strp = (struct strparser *)desc->arg.data;
334
335 return __strp_recv(desc, orig_skb, orig_offset, orig_len,
336 strp->sk->sk_rcvbuf, strp->sk->sk_rcvtimeo);
337}
338
339static int default_read_sock_done(struct strparser *strp, int err)
340{
341 return err;
342}
343
344/* Called with lock held on lower socket */
345static int strp_read_sock(struct strparser *strp)
346{
347 struct socket *sock = strp->sk->sk_socket;
348 read_descriptor_t desc;
349
350 if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
351 return -EBUSY;
352
353 desc.arg.data = strp;
354 desc.error = 0;
355 desc.count = 1; /* give more than one skb per call */
356
357 /* sk should be locked here, so okay to do read_sock */
358 sock->ops->read_sock(strp->sk, &desc, strp_recv);
359
360 desc.error = strp->cb.read_sock_done(strp, desc.error);
361
362 return desc.error;
363}
364
365/* Lower sock lock held */
366void strp_data_ready(struct strparser *strp)
367{
368 if (unlikely(strp->stopped) || strp->paused)
369 return;
370
371 /* This check is needed to synchronize with do_strp_work.
372 * do_strp_work acquires a process lock (lock_sock) whereas
373 * the lock held here is bh_lock_sock. The two locks can be
374 * held by different threads at the same time, but bh_lock_sock
375 * allows a thread in BH context to safely check if the process
376 * lock is held. In this case, if the lock is held, queue work.
377 */
378 if (sock_owned_by_user_nocheck(strp->sk)) {
379 queue_work(strp_wq, &strp->work);
380 return;
381 }
382
383 if (strp->need_bytes) {
384 if (strp_peek_len(strp) < strp->need_bytes)
385 return;
386 }
387
388 if (strp_read_sock(strp) == -ENOMEM)
389 queue_work(strp_wq, &strp->work);
390}
391EXPORT_SYMBOL_GPL(strp_data_ready);
392
393static void do_strp_work(struct strparser *strp)
394{
395 /* We need the read lock to synchronize with strp_data_ready. We
396 * need the socket lock for calling strp_read_sock.
397 */
398 strp->cb.lock(strp);
399
400 if (unlikely(strp->stopped))
401 goto out;
402
403 if (strp->paused)
404 goto out;
405
406 if (strp_read_sock(strp) == -ENOMEM)
407 queue_work(strp_wq, &strp->work);
408
409out:
410 strp->cb.unlock(strp);
411}
412
413static void strp_work(struct work_struct *w)
414{
415 do_strp_work(container_of(w, struct strparser, work));
416}
417
418static void strp_msg_timeout(struct work_struct *w)
419{
420 struct strparser *strp = container_of(w, struct strparser,
421 msg_timer_work.work);
422
423 /* Message assembly timed out */
424 STRP_STATS_INCR(strp->stats.msg_timeouts);
425 strp->cb.lock(strp);
426 strp->cb.abort_parser(strp, -ETIMEDOUT);
427 strp->cb.unlock(strp);
428}
429
430static void strp_sock_lock(struct strparser *strp)
431{
432 lock_sock(strp->sk);
433}
434
435static void strp_sock_unlock(struct strparser *strp)
436{
437 release_sock(strp->sk);
438}
439
440int strp_init(struct strparser *strp, struct sock *sk,
441 const struct strp_callbacks *cb)
442{
443
444 if (!cb || !cb->rcv_msg || !cb->parse_msg)
445 return -EINVAL;
446
447 /* The sk (sock) arg determines the mode of the stream parser.
448 *
449 * If the sock is set then the strparser is in receive callback mode.
450 * The upper layer calls strp_data_ready to kick receive processing
451 * and strparser calls the read_sock function on the socket to
452 * get packets.
453 *
454 * If the sock is not set then the strparser is in general mode.
455 * The upper layer calls strp_process for each skb to be parsed.
456 */
457
458 if (!sk) {
459 if (!cb->lock || !cb->unlock)
460 return -EINVAL;
461 }
462
463 memset(strp, 0, sizeof(*strp));
464
465 strp->sk = sk;
466
467 strp->cb.lock = cb->lock ? : strp_sock_lock;
468 strp->cb.unlock = cb->unlock ? : strp_sock_unlock;
469 strp->cb.rcv_msg = cb->rcv_msg;
470 strp->cb.parse_msg = cb->parse_msg;
471 strp->cb.read_sock_done = cb->read_sock_done ? : default_read_sock_done;
472 strp->cb.abort_parser = cb->abort_parser ? : strp_abort_strp;
473
474 INIT_DELAYED_WORK(&strp->msg_timer_work, strp_msg_timeout);
475 INIT_WORK(&strp->work, strp_work);
476
477 return 0;
478}
479EXPORT_SYMBOL_GPL(strp_init);
480
481/* Sock process lock held (lock_sock) */
482void __strp_unpause(struct strparser *strp)
483{
484 strp->paused = 0;
485
486 if (strp->need_bytes) {
487 if (strp_peek_len(strp) < strp->need_bytes)
488 return;
489 }
490 strp_read_sock(strp);
491}
492EXPORT_SYMBOL_GPL(__strp_unpause);
493
494void strp_unpause(struct strparser *strp)
495{
496 strp->paused = 0;
497
498 /* Sync setting paused with RX work */
499 smp_mb();
500
501 queue_work(strp_wq, &strp->work);
502}
503EXPORT_SYMBOL_GPL(strp_unpause);
504
505/* strp must already be stopped so that strp_recv will no longer be called.
506 * Note that strp_done is not called with the lower socket held.
507 */
508void strp_done(struct strparser *strp)
509{
510 WARN_ON(!strp->stopped);
511
512 cancel_delayed_work_sync(&strp->msg_timer_work);
513 cancel_work_sync(&strp->work);
514
515 if (strp->skb_head) {
516 kfree_skb(strp->skb_head);
517 strp->skb_head = NULL;
518 }
519}
520EXPORT_SYMBOL_GPL(strp_done);
521
522void strp_stop(struct strparser *strp)
523{
524 strp->stopped = 1;
525}
526EXPORT_SYMBOL_GPL(strp_stop);
527
528void strp_check_rcv(struct strparser *strp)
529{
530 queue_work(strp_wq, &strp->work);
531}
532EXPORT_SYMBOL_GPL(strp_check_rcv);
533
534static int __init strp_dev_init(void)
535{
536 BUILD_BUG_ON(sizeof(struct sk_skb_cb) >
537 sizeof_field(struct sk_buff, cb));
538
539 strp_wq = create_singlethread_workqueue("kstrp");
540 if (unlikely(!strp_wq))
541 return -ENOMEM;
542
543 return 0;
544}
545device_initcall(strp_dev_init);
1/*
2 * Stream Parser
3 *
4 * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation.
9 */
10
11#include <linux/bpf.h>
12#include <linux/errno.h>
13#include <linux/errqueue.h>
14#include <linux/file.h>
15#include <linux/in.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/net.h>
19#include <linux/netdevice.h>
20#include <linux/poll.h>
21#include <linux/rculist.h>
22#include <linux/skbuff.h>
23#include <linux/socket.h>
24#include <linux/uaccess.h>
25#include <linux/workqueue.h>
26#include <net/strparser.h>
27#include <net/netns/generic.h>
28#include <net/sock.h>
29
30static struct workqueue_struct *strp_wq;
31
32struct _strp_msg {
33 /* Internal cb structure. struct strp_msg must be first for passing
34 * to upper layer.
35 */
36 struct strp_msg strp;
37 int accum_len;
38 int early_eaten;
39};
40
41static inline struct _strp_msg *_strp_msg(struct sk_buff *skb)
42{
43 return (struct _strp_msg *)((void *)skb->cb +
44 offsetof(struct qdisc_skb_cb, data));
45}
46
47/* Lower lock held */
48static void strp_abort_strp(struct strparser *strp, int err)
49{
50 /* Unrecoverable error in receive */
51
52 cancel_delayed_work(&strp->msg_timer_work);
53
54 if (strp->stopped)
55 return;
56
57 strp->stopped = 1;
58
59 if (strp->sk) {
60 struct sock *sk = strp->sk;
61
62 /* Report an error on the lower socket */
63 sk->sk_err = -err;
64 sk->sk_error_report(sk);
65 }
66}
67
68static void strp_start_timer(struct strparser *strp, long timeo)
69{
70 if (timeo && timeo != LONG_MAX)
71 mod_delayed_work(strp_wq, &strp->msg_timer_work, timeo);
72}
73
74/* Lower lock held */
75static void strp_parser_err(struct strparser *strp, int err,
76 read_descriptor_t *desc)
77{
78 desc->error = err;
79 kfree_skb(strp->skb_head);
80 strp->skb_head = NULL;
81 strp->cb.abort_parser(strp, err);
82}
83
84static inline int strp_peek_len(struct strparser *strp)
85{
86 if (strp->sk) {
87 struct socket *sock = strp->sk->sk_socket;
88
89 return sock->ops->peek_len(sock);
90 }
91
92 /* If we don't have an associated socket there's nothing to peek.
93 * Return int max to avoid stopping the strparser.
94 */
95
96 return INT_MAX;
97}
98
99/* Lower socket lock held */
100static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
101 unsigned int orig_offset, size_t orig_len,
102 size_t max_msg_size, long timeo)
103{
104 struct strparser *strp = (struct strparser *)desc->arg.data;
105 struct _strp_msg *stm;
106 struct sk_buff *head, *skb;
107 size_t eaten = 0, cand_len;
108 ssize_t extra;
109 int err;
110 bool cloned_orig = false;
111
112 if (strp->paused)
113 return 0;
114
115 head = strp->skb_head;
116 if (head) {
117 /* Message already in progress */
118
119 stm = _strp_msg(head);
120 if (unlikely(stm->early_eaten)) {
121 /* Already some number of bytes on the receive sock
122 * data saved in skb_head, just indicate they
123 * are consumed.
124 */
125 eaten = orig_len <= stm->early_eaten ?
126 orig_len : stm->early_eaten;
127 stm->early_eaten -= eaten;
128
129 return eaten;
130 }
131
132 if (unlikely(orig_offset)) {
133 /* Getting data with a non-zero offset when a message is
134 * in progress is not expected. If it does happen, we
135 * need to clone and pull since we can't deal with
136 * offsets in the skbs for a message expect in the head.
137 */
138 orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
139 if (!orig_skb) {
140 STRP_STATS_INCR(strp->stats.mem_fail);
141 desc->error = -ENOMEM;
142 return 0;
143 }
144 if (!pskb_pull(orig_skb, orig_offset)) {
145 STRP_STATS_INCR(strp->stats.mem_fail);
146 kfree_skb(orig_skb);
147 desc->error = -ENOMEM;
148 return 0;
149 }
150 cloned_orig = true;
151 orig_offset = 0;
152 }
153
154 if (!strp->skb_nextp) {
155 /* We are going to append to the frags_list of head.
156 * Need to unshare the frag_list.
157 */
158 err = skb_unclone(head, GFP_ATOMIC);
159 if (err) {
160 STRP_STATS_INCR(strp->stats.mem_fail);
161 desc->error = err;
162 return 0;
163 }
164
165 if (unlikely(skb_shinfo(head)->frag_list)) {
166 /* We can't append to an sk_buff that already
167 * has a frag_list. We create a new head, point
168 * the frag_list of that to the old head, and
169 * then are able to use the old head->next for
170 * appending to the message.
171 */
172 if (WARN_ON(head->next)) {
173 desc->error = -EINVAL;
174 return 0;
175 }
176
177 skb = alloc_skb(0, GFP_ATOMIC);
178 if (!skb) {
179 STRP_STATS_INCR(strp->stats.mem_fail);
180 desc->error = -ENOMEM;
181 return 0;
182 }
183 skb->len = head->len;
184 skb->data_len = head->len;
185 skb->truesize = head->truesize;
186 *_strp_msg(skb) = *_strp_msg(head);
187 strp->skb_nextp = &head->next;
188 skb_shinfo(skb)->frag_list = head;
189 strp->skb_head = skb;
190 head = skb;
191 } else {
192 strp->skb_nextp =
193 &skb_shinfo(head)->frag_list;
194 }
195 }
196 }
197
198 while (eaten < orig_len) {
199 /* Always clone since we will consume something */
200 skb = skb_clone(orig_skb, GFP_ATOMIC);
201 if (!skb) {
202 STRP_STATS_INCR(strp->stats.mem_fail);
203 desc->error = -ENOMEM;
204 break;
205 }
206
207 cand_len = orig_len - eaten;
208
209 head = strp->skb_head;
210 if (!head) {
211 head = skb;
212 strp->skb_head = head;
213 /* Will set skb_nextp on next packet if needed */
214 strp->skb_nextp = NULL;
215 stm = _strp_msg(head);
216 memset(stm, 0, sizeof(*stm));
217 stm->strp.offset = orig_offset + eaten;
218 } else {
219 /* Unclone since we may be appending to an skb that we
220 * already share a frag_list with.
221 */
222 err = skb_unclone(skb, GFP_ATOMIC);
223 if (err) {
224 STRP_STATS_INCR(strp->stats.mem_fail);
225 desc->error = err;
226 break;
227 }
228
229 stm = _strp_msg(head);
230 *strp->skb_nextp = skb;
231 strp->skb_nextp = &skb->next;
232 head->data_len += skb->len;
233 head->len += skb->len;
234 head->truesize += skb->truesize;
235 }
236
237 if (!stm->strp.full_len) {
238 ssize_t len;
239
240 len = (*strp->cb.parse_msg)(strp, head);
241
242 if (!len) {
243 /* Need more header to determine length */
244 if (!stm->accum_len) {
245 /* Start RX timer for new message */
246 strp_start_timer(strp, timeo);
247 }
248 stm->accum_len += cand_len;
249 eaten += cand_len;
250 STRP_STATS_INCR(strp->stats.need_more_hdr);
251 WARN_ON(eaten != orig_len);
252 break;
253 } else if (len < 0) {
254 if (len == -ESTRPIPE && stm->accum_len) {
255 len = -ENODATA;
256 strp->unrecov_intr = 1;
257 } else {
258 strp->interrupted = 1;
259 }
260 strp_parser_err(strp, len, desc);
261 break;
262 } else if (len > max_msg_size) {
263 /* Message length exceeds maximum allowed */
264 STRP_STATS_INCR(strp->stats.msg_too_big);
265 strp_parser_err(strp, -EMSGSIZE, desc);
266 break;
267 } else if (len <= (ssize_t)head->len -
268 skb->len - stm->strp.offset) {
269 /* Length must be into new skb (and also
270 * greater than zero)
271 */
272 STRP_STATS_INCR(strp->stats.bad_hdr_len);
273 strp_parser_err(strp, -EPROTO, desc);
274 break;
275 }
276
277 stm->strp.full_len = len;
278 }
279
280 extra = (ssize_t)(stm->accum_len + cand_len) -
281 stm->strp.full_len;
282
283 if (extra < 0) {
284 /* Message not complete yet. */
285 if (stm->strp.full_len - stm->accum_len >
286 strp_peek_len(strp)) {
287 /* Don't have the whole message in the socket
288 * buffer. Set strp->need_bytes to wait for
289 * the rest of the message. Also, set "early
290 * eaten" since we've already buffered the skb
291 * but don't consume yet per strp_read_sock.
292 */
293
294 if (!stm->accum_len) {
295 /* Start RX timer for new message */
296 strp_start_timer(strp, timeo);
297 }
298
299 stm->accum_len += cand_len;
300 strp->need_bytes = stm->strp.full_len -
301 stm->accum_len;
302 stm->early_eaten = cand_len;
303 STRP_STATS_ADD(strp->stats.bytes, cand_len);
304 desc->count = 0; /* Stop reading socket */
305 break;
306 }
307 stm->accum_len += cand_len;
308 eaten += cand_len;
309 WARN_ON(eaten != orig_len);
310 break;
311 }
312
313 /* Positive extra indicates ore bytes than needed for the
314 * message
315 */
316
317 WARN_ON(extra > cand_len);
318
319 eaten += (cand_len - extra);
320
321 /* Hurray, we have a new message! */
322 cancel_delayed_work(&strp->msg_timer_work);
323 strp->skb_head = NULL;
324 strp->need_bytes = 0;
325 STRP_STATS_INCR(strp->stats.msgs);
326
327 /* Give skb to upper layer */
328 strp->cb.rcv_msg(strp, head);
329
330 if (unlikely(strp->paused)) {
331 /* Upper layer paused strp */
332 break;
333 }
334 }
335
336 if (cloned_orig)
337 kfree_skb(orig_skb);
338
339 STRP_STATS_ADD(strp->stats.bytes, eaten);
340
341 return eaten;
342}
343
344int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
345 unsigned int orig_offset, size_t orig_len,
346 size_t max_msg_size, long timeo)
347{
348 read_descriptor_t desc; /* Dummy arg to strp_recv */
349
350 desc.arg.data = strp;
351
352 return __strp_recv(&desc, orig_skb, orig_offset, orig_len,
353 max_msg_size, timeo);
354}
355EXPORT_SYMBOL_GPL(strp_process);
356
357static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
358 unsigned int orig_offset, size_t orig_len)
359{
360 struct strparser *strp = (struct strparser *)desc->arg.data;
361
362 return __strp_recv(desc, orig_skb, orig_offset, orig_len,
363 strp->sk->sk_rcvbuf, strp->sk->sk_rcvtimeo);
364}
365
366static int default_read_sock_done(struct strparser *strp, int err)
367{
368 return err;
369}
370
371/* Called with lock held on lower socket */
372static int strp_read_sock(struct strparser *strp)
373{
374 struct socket *sock = strp->sk->sk_socket;
375 read_descriptor_t desc;
376
377 if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
378 return -EBUSY;
379
380 desc.arg.data = strp;
381 desc.error = 0;
382 desc.count = 1; /* give more than one skb per call */
383
384 /* sk should be locked here, so okay to do read_sock */
385 sock->ops->read_sock(strp->sk, &desc, strp_recv);
386
387 desc.error = strp->cb.read_sock_done(strp, desc.error);
388
389 return desc.error;
390}
391
392/* Lower sock lock held */
393void strp_data_ready(struct strparser *strp)
394{
395 if (unlikely(strp->stopped))
396 return;
397
398 /* This check is needed to synchronize with do_strp_work.
399 * do_strp_work acquires a process lock (lock_sock) whereas
400 * the lock held here is bh_lock_sock. The two locks can be
401 * held by different threads at the same time, but bh_lock_sock
402 * allows a thread in BH context to safely check if the process
403 * lock is held. In this case, if the lock is held, queue work.
404 */
405 if (sock_owned_by_user_nocheck(strp->sk)) {
406 queue_work(strp_wq, &strp->work);
407 return;
408 }
409
410 if (strp->paused)
411 return;
412
413 if (strp->need_bytes) {
414 if (strp_peek_len(strp) < strp->need_bytes)
415 return;
416 }
417
418 if (strp_read_sock(strp) == -ENOMEM)
419 queue_work(strp_wq, &strp->work);
420}
421EXPORT_SYMBOL_GPL(strp_data_ready);
422
423static void do_strp_work(struct strparser *strp)
424{
425 read_descriptor_t rd_desc;
426
427 /* We need the read lock to synchronize with strp_data_ready. We
428 * need the socket lock for calling strp_read_sock.
429 */
430 strp->cb.lock(strp);
431
432 if (unlikely(strp->stopped))
433 goto out;
434
435 if (strp->paused)
436 goto out;
437
438 rd_desc.arg.data = strp;
439
440 if (strp_read_sock(strp) == -ENOMEM)
441 queue_work(strp_wq, &strp->work);
442
443out:
444 strp->cb.unlock(strp);
445}
446
447static void strp_work(struct work_struct *w)
448{
449 do_strp_work(container_of(w, struct strparser, work));
450}
451
452static void strp_msg_timeout(struct work_struct *w)
453{
454 struct strparser *strp = container_of(w, struct strparser,
455 msg_timer_work.work);
456
457 /* Message assembly timed out */
458 STRP_STATS_INCR(strp->stats.msg_timeouts);
459 strp->cb.lock(strp);
460 strp->cb.abort_parser(strp, -ETIMEDOUT);
461 strp->cb.unlock(strp);
462}
463
464static void strp_sock_lock(struct strparser *strp)
465{
466 lock_sock(strp->sk);
467}
468
469static void strp_sock_unlock(struct strparser *strp)
470{
471 release_sock(strp->sk);
472}
473
474int strp_init(struct strparser *strp, struct sock *sk,
475 const struct strp_callbacks *cb)
476{
477
478 if (!cb || !cb->rcv_msg || !cb->parse_msg)
479 return -EINVAL;
480
481 /* The sk (sock) arg determines the mode of the stream parser.
482 *
483 * If the sock is set then the strparser is in receive callback mode.
484 * The upper layer calls strp_data_ready to kick receive processing
485 * and strparser calls the read_sock function on the socket to
486 * get packets.
487 *
488 * If the sock is not set then the strparser is in general mode.
489 * The upper layer calls strp_process for each skb to be parsed.
490 */
491
492 if (!sk) {
493 if (!cb->lock || !cb->unlock)
494 return -EINVAL;
495 }
496
497 memset(strp, 0, sizeof(*strp));
498
499 strp->sk = sk;
500
501 strp->cb.lock = cb->lock ? : strp_sock_lock;
502 strp->cb.unlock = cb->unlock ? : strp_sock_unlock;
503 strp->cb.rcv_msg = cb->rcv_msg;
504 strp->cb.parse_msg = cb->parse_msg;
505 strp->cb.read_sock_done = cb->read_sock_done ? : default_read_sock_done;
506 strp->cb.abort_parser = cb->abort_parser ? : strp_abort_strp;
507
508 INIT_DELAYED_WORK(&strp->msg_timer_work, strp_msg_timeout);
509 INIT_WORK(&strp->work, strp_work);
510
511 return 0;
512}
513EXPORT_SYMBOL_GPL(strp_init);
514
515void strp_unpause(struct strparser *strp)
516{
517 strp->paused = 0;
518
519 /* Sync setting paused with RX work */
520 smp_mb();
521
522 queue_work(strp_wq, &strp->work);
523}
524EXPORT_SYMBOL_GPL(strp_unpause);
525
526/* strp must already be stopped so that strp_recv will no longer be called.
527 * Note that strp_done is not called with the lower socket held.
528 */
529void strp_done(struct strparser *strp)
530{
531 WARN_ON(!strp->stopped);
532
533 cancel_delayed_work_sync(&strp->msg_timer_work);
534 cancel_work_sync(&strp->work);
535
536 if (strp->skb_head) {
537 kfree_skb(strp->skb_head);
538 strp->skb_head = NULL;
539 }
540}
541EXPORT_SYMBOL_GPL(strp_done);
542
543void strp_stop(struct strparser *strp)
544{
545 strp->stopped = 1;
546}
547EXPORT_SYMBOL_GPL(strp_stop);
548
549void strp_check_rcv(struct strparser *strp)
550{
551 queue_work(strp_wq, &strp->work);
552}
553EXPORT_SYMBOL_GPL(strp_check_rcv);
554
555static int __init strp_mod_init(void)
556{
557 strp_wq = create_singlethread_workqueue("kstrp");
558
559 return 0;
560}
561
562static void __exit strp_mod_exit(void)
563{
564 destroy_workqueue(strp_wq);
565}
566module_init(strp_mod_init);
567module_exit(strp_mod_exit);
568MODULE_LICENSE("GPL");