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1 | /* |
2 | * SUCS NET3: |
3 | * |
4 | * Generic datagram handling routines. These are generic for all |
5 | * protocols. Possibly a generic IP version on top of these would |
6 | * make sense. Not tonight however 8-). |
7 | * This is used because UDP, RAW, PACKET, DDP, IPX, AX.25 and |
8 | * NetROM layer all have identical poll code and mostly |
9 | * identical recvmsg() code. So we share it here. The poll was |
10 | * shared before but buried in udp.c so I moved it. |
11 | * |
12 | * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>. (datagram_poll() from old |
13 | * udp.c code) |
14 | * |
15 | * Fixes: |
16 | * Alan Cox : NULL return from skb_peek_copy() |
17 | * understood |
18 | * Alan Cox : Rewrote skb_read_datagram to avoid the |
19 | * skb_peek_copy stuff. |
20 | * Alan Cox : Added support for SOCK_SEQPACKET. |
21 | * IPX can no longer use the SO_TYPE hack |
22 | * but AX.25 now works right, and SPX is |
23 | * feasible. |
24 | * Alan Cox : Fixed write poll of non IP protocol |
25 | * crash. |
26 | * Florian La Roche: Changed for my new skbuff handling. |
27 | * Darryl Miles : Fixed non-blocking SOCK_SEQPACKET. |
28 | * Linus Torvalds : BSD semantic fixes. |
29 | * Alan Cox : Datagram iovec handling |
30 | * Darryl Miles : Fixed non-blocking SOCK_STREAM. |
31 | * Alan Cox : POSIXisms |
32 | * Pete Wyckoff : Unconnected accept() fix. |
33 | * |
34 | */ |
35 | |
36 | #include <linux/module.h> |
37 | #include <linux/types.h> |
38 | #include <linux/kernel.h> |
39 | #include <asm/uaccess.h> |
40 | #include <asm/system.h> |
41 | #include <linux/mm.h> |
42 | #include <linux/interrupt.h> |
43 | #include <linux/errno.h> |
44 | #include <linux/sched.h> |
45 | #include <linux/inet.h> |
46 | #include <linux/netdevice.h> |
47 | #include <linux/rtnetlink.h> |
48 | #include <linux/poll.h> |
49 | #include <linux/highmem.h> |
50 | #include <linux/spinlock.h> |
51 | #include <linux/slab.h> |
52 | |
53 | #include <net/protocol.h> |
54 | #include <linux/skbuff.h> |
55 | |
56 | #include <net/checksum.h> |
57 | #include <net/sock.h> |
58 | #include <net/tcp_states.h> |
59 | #include <trace/events/skb.h> |
60 | |
61 | /* |
62 | * Is a socket 'connection oriented' ? |
63 | */ |
64 | static inline int connection_based(struct sock *sk) |
65 | { |
66 | return sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM; |
67 | } |
68 | |
69 | static int receiver_wake_function(wait_queue_t *wait, unsigned mode, int sync, |
70 | void *key) |
71 | { |
72 | unsigned long bits = (unsigned long)key; |
73 | |
74 | /* |
75 | * Avoid a wakeup if event not interesting for us |
76 | */ |
77 | if (bits && !(bits & (POLLIN | POLLERR))) |
78 | return 0; |
79 | return autoremove_wake_function(wait, mode, sync, key); |
80 | } |
81 | /* |
82 | * Wait for a packet.. |
83 | */ |
84 | static int wait_for_packet(struct sock *sk, int *err, long *timeo_p) |
85 | { |
86 | int error; |
87 | DEFINE_WAIT_FUNC(wait, receiver_wake_function); |
88 | |
89 | prepare_to_wait_exclusive(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); |
90 | |
91 | /* Socket errors? */ |
92 | error = sock_error(sk); |
93 | if (error) |
94 | goto out_err; |
95 | |
96 | if (!skb_queue_empty(&sk->sk_receive_queue)) |
97 | goto out; |
98 | |
99 | /* Socket shut down? */ |
100 | if (sk->sk_shutdown & RCV_SHUTDOWN) |
101 | goto out_noerr; |
102 | |
103 | /* Sequenced packets can come disconnected. |
104 | * If so we report the problem |
105 | */ |
106 | error = -ENOTCONN; |
107 | if (connection_based(sk) && |
108 | !(sk->sk_state == TCP_ESTABLISHED || sk->sk_state == TCP_LISTEN)) |
109 | goto out_err; |
110 | |
111 | /* handle signals */ |
112 | if (signal_pending(current)) |
113 | goto interrupted; |
114 | |
115 | error = 0; |
116 | *timeo_p = schedule_timeout(*timeo_p); |
117 | out: |
118 | finish_wait(sk_sleep(sk), &wait); |
119 | return error; |
120 | interrupted: |
121 | error = sock_intr_errno(*timeo_p); |
122 | out_err: |
123 | *err = error; |
124 | goto out; |
125 | out_noerr: |
126 | *err = 0; |
127 | error = 1; |
128 | goto out; |
129 | } |
130 | |
131 | /** |
132 | * __skb_recv_datagram - Receive a datagram skbuff |
133 | * @sk: socket |
134 | * @flags: MSG_ flags |
135 | * @peeked: returns non-zero if this packet has been seen before |
136 | * @err: error code returned |
137 | * |
138 | * Get a datagram skbuff, understands the peeking, nonblocking wakeups |
139 | * and possible races. This replaces identical code in packet, raw and |
140 | * udp, as well as the IPX AX.25 and Appletalk. It also finally fixes |
141 | * the long standing peek and read race for datagram sockets. If you |
142 | * alter this routine remember it must be re-entrant. |
143 | * |
144 | * This function will lock the socket if a skb is returned, so the caller |
145 | * needs to unlock the socket in that case (usually by calling |
146 | * skb_free_datagram) |
147 | * |
148 | * * It does not lock socket since today. This function is |
149 | * * free of race conditions. This measure should/can improve |
150 | * * significantly datagram socket latencies at high loads, |
151 | * * when data copying to user space takes lots of time. |
152 | * * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet |
153 | * * 8) Great win.) |
154 | * * --ANK (980729) |
155 | * |
156 | * The order of the tests when we find no data waiting are specified |
157 | * quite explicitly by POSIX 1003.1g, don't change them without having |
158 | * the standard around please. |
159 | */ |
160 | struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags, |
161 | int *peeked, int *err) |
162 | { |
163 | struct sk_buff *skb; |
164 | long timeo; |
165 | /* |
166 | * Caller is allowed not to check sk->sk_err before skb_recv_datagram() |
167 | */ |
168 | int error = sock_error(sk); |
169 | |
170 | if (error) |
171 | goto no_packet; |
172 | |
173 | timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); |
174 | |
175 | do { |
176 | /* Again only user level code calls this function, so nothing |
177 | * interrupt level will suddenly eat the receive_queue. |
178 | * |
179 | * Look at current nfs client by the way... |
180 | * However, this function was corrent in any case. 8) |
181 | */ |
182 | unsigned long cpu_flags; |
183 | |
184 | spin_lock_irqsave(&sk->sk_receive_queue.lock, cpu_flags); |
185 | skb = skb_peek(&sk->sk_receive_queue); |
186 | if (skb) { |
187 | *peeked = skb->peeked; |
188 | if (flags & MSG_PEEK) { |
189 | skb->peeked = 1; |
190 | atomic_inc(&skb->users); |
191 | } else |
192 | __skb_unlink(skb, &sk->sk_receive_queue); |
193 | } |
194 | spin_unlock_irqrestore(&sk->sk_receive_queue.lock, cpu_flags); |
195 | |
196 | if (skb) |
197 | return skb; |
198 | |
199 | /* User doesn't want to wait */ |
200 | error = -EAGAIN; |
201 | if (!timeo) |
202 | goto no_packet; |
203 | |
204 | } while (!wait_for_packet(sk, err, &timeo)); |
205 | |
206 | return NULL; |
207 | |
208 | no_packet: |
209 | *err = error; |
210 | return NULL; |
211 | } |
212 | EXPORT_SYMBOL(__skb_recv_datagram); |
213 | |
214 | struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, |
215 | int noblock, int *err) |
216 | { |
217 | int peeked; |
218 | |
219 | return __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0), |
220 | &peeked, err); |
221 | } |
222 | EXPORT_SYMBOL(skb_recv_datagram); |
223 | |
224 | void skb_free_datagram(struct sock *sk, struct sk_buff *skb) |
225 | { |
226 | consume_skb(skb); |
227 | sk_mem_reclaim_partial(sk); |
228 | } |
229 | EXPORT_SYMBOL(skb_free_datagram); |
230 | |
231 | void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) |
232 | { |
233 | bool slow; |
234 | |
235 | if (likely(atomic_read(&skb->users) == 1)) |
236 | smp_rmb(); |
237 | else if (likely(!atomic_dec_and_test(&skb->users))) |
238 | return; |
239 | |
240 | slow = lock_sock_fast(sk); |
241 | skb_orphan(skb); |
242 | sk_mem_reclaim_partial(sk); |
243 | unlock_sock_fast(sk, slow); |
244 | |
245 | /* skb is now orphaned, can be freed outside of locked section */ |
246 | __kfree_skb(skb); |
247 | } |
248 | EXPORT_SYMBOL(skb_free_datagram_locked); |
249 | |
250 | /** |
251 | * skb_kill_datagram - Free a datagram skbuff forcibly |
252 | * @sk: socket |
253 | * @skb: datagram skbuff |
254 | * @flags: MSG_ flags |
255 | * |
256 | * This function frees a datagram skbuff that was received by |
257 | * skb_recv_datagram. The flags argument must match the one |
258 | * used for skb_recv_datagram. |
259 | * |
260 | * If the MSG_PEEK flag is set, and the packet is still on the |
261 | * receive queue of the socket, it will be taken off the queue |
262 | * before it is freed. |
263 | * |
264 | * This function currently only disables BH when acquiring the |
265 | * sk_receive_queue lock. Therefore it must not be used in a |
266 | * context where that lock is acquired in an IRQ context. |
267 | * |
268 | * It returns 0 if the packet was removed by us. |
269 | */ |
270 | |
271 | int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags) |
272 | { |
273 | int err = 0; |
274 | |
275 | if (flags & MSG_PEEK) { |
276 | err = -ENOENT; |
277 | spin_lock_bh(&sk->sk_receive_queue.lock); |
278 | if (skb == skb_peek(&sk->sk_receive_queue)) { |
279 | __skb_unlink(skb, &sk->sk_receive_queue); |
280 | atomic_dec(&skb->users); |
281 | err = 0; |
282 | } |
283 | spin_unlock_bh(&sk->sk_receive_queue.lock); |
284 | } |
285 | |
286 | kfree_skb(skb); |
287 | atomic_inc(&sk->sk_drops); |
288 | sk_mem_reclaim_partial(sk); |
289 | |
290 | return err; |
291 | } |
292 | EXPORT_SYMBOL(skb_kill_datagram); |
293 | |
294 | /** |
295 | * skb_copy_datagram_iovec - Copy a datagram to an iovec. |
296 | * @skb: buffer to copy |
297 | * @offset: offset in the buffer to start copying from |
298 | * @to: io vector to copy to |
299 | * @len: amount of data to copy from buffer to iovec |
300 | * |
301 | * Note: the iovec is modified during the copy. |
302 | */ |
303 | int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset, |
304 | struct iovec *to, int len) |
305 | { |
306 | int start = skb_headlen(skb); |
307 | int i, copy = start - offset; |
308 | struct sk_buff *frag_iter; |
309 | |
310 | trace_skb_copy_datagram_iovec(skb, len); |
311 | |
312 | /* Copy header. */ |
313 | if (copy > 0) { |
314 | if (copy > len) |
315 | copy = len; |
316 | if (memcpy_toiovec(to, skb->data + offset, copy)) |
317 | goto fault; |
318 | if ((len -= copy) == 0) |
319 | return 0; |
320 | offset += copy; |
321 | } |
322 | |
323 | /* Copy paged appendix. Hmm... why does this look so complicated? */ |
324 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
325 | int end; |
326 | |
327 | WARN_ON(start > offset + len); |
328 | |
329 | end = start + skb_shinfo(skb)->frags[i].size; |
330 | if ((copy = end - offset) > 0) { |
331 | int err; |
332 | u8 *vaddr; |
333 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
334 | struct page *page = frag->page; |
335 | |
336 | if (copy > len) |
337 | copy = len; |
338 | vaddr = kmap(page); |
339 | err = memcpy_toiovec(to, vaddr + frag->page_offset + |
340 | offset - start, copy); |
341 | kunmap(page); |
342 | if (err) |
343 | goto fault; |
344 | if (!(len -= copy)) |
345 | return 0; |
346 | offset += copy; |
347 | } |
348 | start = end; |
349 | } |
350 | |
351 | skb_walk_frags(skb, frag_iter) { |
352 | int end; |
353 | |
354 | WARN_ON(start > offset + len); |
355 | |
356 | end = start + frag_iter->len; |
357 | if ((copy = end - offset) > 0) { |
358 | if (copy > len) |
359 | copy = len; |
360 | if (skb_copy_datagram_iovec(frag_iter, |
361 | offset - start, |
362 | to, copy)) |
363 | goto fault; |
364 | if ((len -= copy) == 0) |
365 | return 0; |
366 | offset += copy; |
367 | } |
368 | start = end; |
369 | } |
370 | if (!len) |
371 | return 0; |
372 | |
373 | fault: |
374 | return -EFAULT; |
375 | } |
376 | EXPORT_SYMBOL(skb_copy_datagram_iovec); |
377 | |
378 | /** |
379 | * skb_copy_datagram_const_iovec - Copy a datagram to an iovec. |
380 | * @skb: buffer to copy |
381 | * @offset: offset in the buffer to start copying from |
382 | * @to: io vector to copy to |
383 | * @to_offset: offset in the io vector to start copying to |
384 | * @len: amount of data to copy from buffer to iovec |
385 | * |
386 | * Returns 0 or -EFAULT. |
387 | * Note: the iovec is not modified during the copy. |
388 | */ |
389 | int skb_copy_datagram_const_iovec(const struct sk_buff *skb, int offset, |
390 | const struct iovec *to, int to_offset, |
391 | int len) |
392 | { |
393 | int start = skb_headlen(skb); |
394 | int i, copy = start - offset; |
395 | struct sk_buff *frag_iter; |
396 | |
397 | /* Copy header. */ |
398 | if (copy > 0) { |
399 | if (copy > len) |
400 | copy = len; |
401 | if (memcpy_toiovecend(to, skb->data + offset, to_offset, copy)) |
402 | goto fault; |
403 | if ((len -= copy) == 0) |
404 | return 0; |
405 | offset += copy; |
406 | to_offset += copy; |
407 | } |
408 | |
409 | /* Copy paged appendix. Hmm... why does this look so complicated? */ |
410 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
411 | int end; |
412 | |
413 | WARN_ON(start > offset + len); |
414 | |
415 | end = start + skb_shinfo(skb)->frags[i].size; |
416 | if ((copy = end - offset) > 0) { |
417 | int err; |
418 | u8 *vaddr; |
419 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
420 | struct page *page = frag->page; |
421 | |
422 | if (copy > len) |
423 | copy = len; |
424 | vaddr = kmap(page); |
425 | err = memcpy_toiovecend(to, vaddr + frag->page_offset + |
426 | offset - start, to_offset, copy); |
427 | kunmap(page); |
428 | if (err) |
429 | goto fault; |
430 | if (!(len -= copy)) |
431 | return 0; |
432 | offset += copy; |
433 | to_offset += copy; |
434 | } |
435 | start = end; |
436 | } |
437 | |
438 | skb_walk_frags(skb, frag_iter) { |
439 | int end; |
440 | |
441 | WARN_ON(start > offset + len); |
442 | |
443 | end = start + frag_iter->len; |
444 | if ((copy = end - offset) > 0) { |
445 | if (copy > len) |
446 | copy = len; |
447 | if (skb_copy_datagram_const_iovec(frag_iter, |
448 | offset - start, |
449 | to, to_offset, |
450 | copy)) |
451 | goto fault; |
452 | if ((len -= copy) == 0) |
453 | return 0; |
454 | offset += copy; |
455 | to_offset += copy; |
456 | } |
457 | start = end; |
458 | } |
459 | if (!len) |
460 | return 0; |
461 | |
462 | fault: |
463 | return -EFAULT; |
464 | } |
465 | EXPORT_SYMBOL(skb_copy_datagram_const_iovec); |
466 | |
467 | /** |
468 | * skb_copy_datagram_from_iovec - Copy a datagram from an iovec. |
469 | * @skb: buffer to copy |
470 | * @offset: offset in the buffer to start copying to |
471 | * @from: io vector to copy to |
472 | * @from_offset: offset in the io vector to start copying from |
473 | * @len: amount of data to copy to buffer from iovec |
474 | * |
475 | * Returns 0 or -EFAULT. |
476 | * Note: the iovec is not modified during the copy. |
477 | */ |
478 | int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, |
479 | const struct iovec *from, int from_offset, |
480 | int len) |
481 | { |
482 | int start = skb_headlen(skb); |
483 | int i, copy = start - offset; |
484 | struct sk_buff *frag_iter; |
485 | |
486 | /* Copy header. */ |
487 | if (copy > 0) { |
488 | if (copy > len) |
489 | copy = len; |
490 | if (memcpy_fromiovecend(skb->data + offset, from, from_offset, |
491 | copy)) |
492 | goto fault; |
493 | if ((len -= copy) == 0) |
494 | return 0; |
495 | offset += copy; |
496 | from_offset += copy; |
497 | } |
498 | |
499 | /* Copy paged appendix. Hmm... why does this look so complicated? */ |
500 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
501 | int end; |
502 | |
503 | WARN_ON(start > offset + len); |
504 | |
505 | end = start + skb_shinfo(skb)->frags[i].size; |
506 | if ((copy = end - offset) > 0) { |
507 | int err; |
508 | u8 *vaddr; |
509 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
510 | struct page *page = frag->page; |
511 | |
512 | if (copy > len) |
513 | copy = len; |
514 | vaddr = kmap(page); |
515 | err = memcpy_fromiovecend(vaddr + frag->page_offset + |
516 | offset - start, |
517 | from, from_offset, copy); |
518 | kunmap(page); |
519 | if (err) |
520 | goto fault; |
521 | |
522 | if (!(len -= copy)) |
523 | return 0; |
524 | offset += copy; |
525 | from_offset += copy; |
526 | } |
527 | start = end; |
528 | } |
529 | |
530 | skb_walk_frags(skb, frag_iter) { |
531 | int end; |
532 | |
533 | WARN_ON(start > offset + len); |
534 | |
535 | end = start + frag_iter->len; |
536 | if ((copy = end - offset) > 0) { |
537 | if (copy > len) |
538 | copy = len; |
539 | if (skb_copy_datagram_from_iovec(frag_iter, |
540 | offset - start, |
541 | from, |
542 | from_offset, |
543 | copy)) |
544 | goto fault; |
545 | if ((len -= copy) == 0) |
546 | return 0; |
547 | offset += copy; |
548 | from_offset += copy; |
549 | } |
550 | start = end; |
551 | } |
552 | if (!len) |
553 | return 0; |
554 | |
555 | fault: |
556 | return -EFAULT; |
557 | } |
558 | EXPORT_SYMBOL(skb_copy_datagram_from_iovec); |
559 | |
560 | static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, |
561 | u8 __user *to, int len, |
562 | __wsum *csump) |
563 | { |
564 | int start = skb_headlen(skb); |
565 | int i, copy = start - offset; |
566 | struct sk_buff *frag_iter; |
567 | int pos = 0; |
568 | |
569 | /* Copy header. */ |
570 | if (copy > 0) { |
571 | int err = 0; |
572 | if (copy > len) |
573 | copy = len; |
574 | *csump = csum_and_copy_to_user(skb->data + offset, to, copy, |
575 | *csump, &err); |
576 | if (err) |
577 | goto fault; |
578 | if ((len -= copy) == 0) |
579 | return 0; |
580 | offset += copy; |
581 | to += copy; |
582 | pos = copy; |
583 | } |
584 | |
585 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
586 | int end; |
587 | |
588 | WARN_ON(start > offset + len); |
589 | |
590 | end = start + skb_shinfo(skb)->frags[i].size; |
591 | if ((copy = end - offset) > 0) { |
592 | __wsum csum2; |
593 | int err = 0; |
594 | u8 *vaddr; |
595 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
596 | struct page *page = frag->page; |
597 | |
598 | if (copy > len) |
599 | copy = len; |
600 | vaddr = kmap(page); |
601 | csum2 = csum_and_copy_to_user(vaddr + |
602 | frag->page_offset + |
603 | offset - start, |
604 | to, copy, 0, &err); |
605 | kunmap(page); |
606 | if (err) |
607 | goto fault; |
608 | *csump = csum_block_add(*csump, csum2, pos); |
609 | if (!(len -= copy)) |
610 | return 0; |
611 | offset += copy; |
612 | to += copy; |
613 | pos += copy; |
614 | } |
615 | start = end; |
616 | } |
617 | |
618 | skb_walk_frags(skb, frag_iter) { |
619 | int end; |
620 | |
621 | WARN_ON(start > offset + len); |
622 | |
623 | end = start + frag_iter->len; |
624 | if ((copy = end - offset) > 0) { |
625 | __wsum csum2 = 0; |
626 | if (copy > len) |
627 | copy = len; |
628 | if (skb_copy_and_csum_datagram(frag_iter, |
629 | offset - start, |
630 | to, copy, |
631 | &csum2)) |
632 | goto fault; |
633 | *csump = csum_block_add(*csump, csum2, pos); |
634 | if ((len -= copy) == 0) |
635 | return 0; |
636 | offset += copy; |
637 | to += copy; |
638 | pos += copy; |
639 | } |
640 | start = end; |
641 | } |
642 | if (!len) |
643 | return 0; |
644 | |
645 | fault: |
646 | return -EFAULT; |
647 | } |
648 | |
649 | __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len) |
650 | { |
651 | __sum16 sum; |
652 | |
653 | sum = csum_fold(skb_checksum(skb, 0, len, skb->csum)); |
654 | if (likely(!sum)) { |
655 | if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) |
656 | netdev_rx_csum_fault(skb->dev); |
657 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
658 | } |
659 | return sum; |
660 | } |
661 | EXPORT_SYMBOL(__skb_checksum_complete_head); |
662 | |
663 | __sum16 __skb_checksum_complete(struct sk_buff *skb) |
664 | { |
665 | return __skb_checksum_complete_head(skb, skb->len); |
666 | } |
667 | EXPORT_SYMBOL(__skb_checksum_complete); |
668 | |
669 | /** |
670 | * skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec. |
671 | * @skb: skbuff |
672 | * @hlen: hardware length |
673 | * @iov: io vector |
674 | * |
675 | * Caller _must_ check that skb will fit to this iovec. |
676 | * |
677 | * Returns: 0 - success. |
678 | * -EINVAL - checksum failure. |
679 | * -EFAULT - fault during copy. Beware, in this case iovec |
680 | * can be modified! |
681 | */ |
682 | int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, |
683 | int hlen, struct iovec *iov) |
684 | { |
685 | __wsum csum; |
686 | int chunk = skb->len - hlen; |
687 | |
688 | if (!chunk) |
689 | return 0; |
690 | |
691 | /* Skip filled elements. |
692 | * Pretty silly, look at memcpy_toiovec, though 8) |
693 | */ |
694 | while (!iov->iov_len) |
695 | iov++; |
696 | |
697 | if (iov->iov_len < chunk) { |
698 | if (__skb_checksum_complete(skb)) |
699 | goto csum_error; |
700 | if (skb_copy_datagram_iovec(skb, hlen, iov, chunk)) |
701 | goto fault; |
702 | } else { |
703 | csum = csum_partial(skb->data, hlen, skb->csum); |
704 | if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base, |
705 | chunk, &csum)) |
706 | goto fault; |
707 | if (csum_fold(csum)) |
708 | goto csum_error; |
709 | if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) |
710 | netdev_rx_csum_fault(skb->dev); |
711 | iov->iov_len -= chunk; |
712 | iov->iov_base += chunk; |
713 | } |
714 | return 0; |
715 | csum_error: |
716 | return -EINVAL; |
717 | fault: |
718 | return -EFAULT; |
719 | } |
720 | EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec); |
721 | |
722 | /** |
723 | * datagram_poll - generic datagram poll |
724 | * @file: file struct |
725 | * @sock: socket |
726 | * @wait: poll table |
727 | * |
728 | * Datagram poll: Again totally generic. This also handles |
729 | * sequenced packet sockets providing the socket receive queue |
730 | * is only ever holding data ready to receive. |
731 | * |
732 | * Note: when you _don't_ use this routine for this protocol, |
733 | * and you use a different write policy from sock_writeable() |
734 | * then please supply your own write_space callback. |
735 | */ |
736 | unsigned int datagram_poll(struct file *file, struct socket *sock, |
737 | poll_table *wait) |
738 | { |
739 | struct sock *sk = sock->sk; |
740 | unsigned int mask; |
741 | |
742 | sock_poll_wait(file, sk_sleep(sk), wait); |
743 | mask = 0; |
744 | |
745 | /* exceptional events? */ |
746 | if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) |
747 | mask |= POLLERR; |
748 | if (sk->sk_shutdown & RCV_SHUTDOWN) |
749 | mask |= POLLRDHUP; |
750 | if (sk->sk_shutdown == SHUTDOWN_MASK) |
751 | mask |= POLLHUP; |
752 | |
753 | /* readable? */ |
754 | if (!skb_queue_empty(&sk->sk_receive_queue) || |
755 | (sk->sk_shutdown & RCV_SHUTDOWN)) |
756 | mask |= POLLIN | POLLRDNORM; |
757 | |
758 | /* Connection-based need to check for termination and startup */ |
759 | if (connection_based(sk)) { |
760 | if (sk->sk_state == TCP_CLOSE) |
761 | mask |= POLLHUP; |
762 | /* connection hasn't started yet? */ |
763 | if (sk->sk_state == TCP_SYN_SENT) |
764 | return mask; |
765 | } |
766 | |
767 | /* writable? */ |
768 | if (sock_writeable(sk)) |
769 | mask |= POLLOUT | POLLWRNORM | POLLWRBAND; |
770 | else |
771 | set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); |
772 | |
773 | return mask; |
774 | } |
775 | EXPORT_SYMBOL(datagram_poll); |
776 |
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