Merge tag 'arc-v3.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[linux-2.6-block.git] / net / core / datagram.c
CommitLineData
1da177e4
LT
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 *
113aa838 12 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>. (datagram_poll() from old
1da177e4
LT
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>
1da177e4
LT
40#include <linux/mm.h>
41#include <linux/interrupt.h>
42#include <linux/errno.h>
43#include <linux/sched.h>
44#include <linux/inet.h>
1da177e4
LT
45#include <linux/netdevice.h>
46#include <linux/rtnetlink.h>
47#include <linux/poll.h>
48#include <linux/highmem.h>
3305b80c 49#include <linux/spinlock.h>
5a0e3ad6 50#include <linux/slab.h>
1da177e4
LT
51
52#include <net/protocol.h>
53#include <linux/skbuff.h>
1da177e4 54
c752f073
ACM
55#include <net/checksum.h>
56#include <net/sock.h>
57#include <net/tcp_states.h>
e9b3cc1b 58#include <trace/events/skb.h>
1da177e4
LT
59
60/*
61 * Is a socket 'connection oriented' ?
62 */
63static inline int connection_based(struct sock *sk)
64{
65 return sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM;
66}
67
95c96174 68static int receiver_wake_function(wait_queue_t *wait, unsigned int mode, int sync,
bf368e4e
ED
69 void *key)
70{
71 unsigned long bits = (unsigned long)key;
72
73 /*
74 * Avoid a wakeup if event not interesting for us
75 */
76 if (bits && !(bits & (POLLIN | POLLERR)))
77 return 0;
78 return autoremove_wake_function(wait, mode, sync, key);
79}
1da177e4 80/*
39cc8613 81 * Wait for the last received packet to be different from skb
1da177e4 82 */
39cc8613
BP
83static int wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
84 const struct sk_buff *skb)
1da177e4
LT
85{
86 int error;
bf368e4e 87 DEFINE_WAIT_FUNC(wait, receiver_wake_function);
1da177e4 88
aa395145 89 prepare_to_wait_exclusive(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1da177e4
LT
90
91 /* Socket errors? */
92 error = sock_error(sk);
93 if (error)
94 goto out_err;
95
39cc8613 96 if (sk->sk_receive_queue.prev != skb)
1da177e4
LT
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);
117out:
aa395145 118 finish_wait(sk_sleep(sk), &wait);
1da177e4
LT
119 return error;
120interrupted:
121 error = sock_intr_errno(*timeo_p);
122out_err:
123 *err = error;
124 goto out;
125out_noerr:
126 *err = 0;
127 error = 1;
128 goto out;
129}
130
131/**
a59322be 132 * __skb_recv_datagram - Receive a datagram skbuff
4dc3b16b
PP
133 * @sk: socket
134 * @flags: MSG_ flags
39cc8613 135 * @peeked: returns non-zero if this packet has been seen before
3f518bf7
PE
136 * @off: an offset in bytes to peek skb from. Returns an offset
137 * within an skb where data actually starts
4dc3b16b 138 * @err: error code returned
1da177e4
LT
139 *
140 * Get a datagram skbuff, understands the peeking, nonblocking wakeups
141 * and possible races. This replaces identical code in packet, raw and
142 * udp, as well as the IPX AX.25 and Appletalk. It also finally fixes
143 * the long standing peek and read race for datagram sockets. If you
144 * alter this routine remember it must be re-entrant.
145 *
146 * This function will lock the socket if a skb is returned, so the caller
147 * needs to unlock the socket in that case (usually by calling
148 * skb_free_datagram)
149 *
150 * * It does not lock socket since today. This function is
151 * * free of race conditions. This measure should/can improve
152 * * significantly datagram socket latencies at high loads,
153 * * when data copying to user space takes lots of time.
154 * * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet
155 * * 8) Great win.)
156 * * --ANK (980729)
157 *
158 * The order of the tests when we find no data waiting are specified
159 * quite explicitly by POSIX 1003.1g, don't change them without having
160 * the standard around please.
161 */
95c96174 162struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
3f518bf7 163 int *peeked, int *off, int *err)
1da177e4 164{
39cc8613 165 struct sk_buff *skb, *last;
1da177e4
LT
166 long timeo;
167 /*
168 * Caller is allowed not to check sk->sk_err before skb_recv_datagram()
169 */
170 int error = sock_error(sk);
171
172 if (error)
173 goto no_packet;
174
a59322be 175 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1da177e4
LT
176
177 do {
178 /* Again only user level code calls this function, so nothing
179 * interrupt level will suddenly eat the receive_queue.
180 *
181 * Look at current nfs client by the way...
8917a3c0 182 * However, this function was correct in any case. 8)
1da177e4 183 */
a59322be 184 unsigned long cpu_flags;
4934b032 185 struct sk_buff_head *queue = &sk->sk_receive_queue;
39cc8613 186 int _off = *off;
a59322be 187
39cc8613 188 last = (struct sk_buff *)queue;
4934b032 189 spin_lock_irqsave(&queue->lock, cpu_flags);
3f518bf7 190 skb_queue_walk(queue, skb) {
39cc8613 191 last = skb;
a59322be
HX
192 *peeked = skb->peeked;
193 if (flags & MSG_PEEK) {
39cc8613 194 if (_off >= skb->len && (skb->len || _off ||
add05ad4 195 skb->peeked)) {
39cc8613 196 _off -= skb->len;
3f518bf7
PE
197 continue;
198 }
a59322be 199 skb->peeked = 1;
1da177e4 200 atomic_inc(&skb->users);
a59322be 201 } else
4934b032 202 __skb_unlink(skb, queue);
1da177e4 203
3f518bf7 204 spin_unlock_irqrestore(&queue->lock, cpu_flags);
39cc8613 205 *off = _off;
1da177e4 206 return skb;
3f518bf7
PE
207 }
208 spin_unlock_irqrestore(&queue->lock, cpu_flags);
1da177e4
LT
209
210 /* User doesn't want to wait */
211 error = -EAGAIN;
212 if (!timeo)
213 goto no_packet;
214
39cc8613 215 } while (!wait_for_more_packets(sk, err, &timeo, last));
1da177e4
LT
216
217 return NULL;
218
219no_packet:
220 *err = error;
221 return NULL;
222}
a59322be
HX
223EXPORT_SYMBOL(__skb_recv_datagram);
224
95c96174 225struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags,
a59322be
HX
226 int noblock, int *err)
227{
3f518bf7 228 int peeked, off = 0;
a59322be
HX
229
230 return __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
3f518bf7 231 &peeked, &off, err);
a59322be 232}
9e34a5b5 233EXPORT_SYMBOL(skb_recv_datagram);
1da177e4
LT
234
235void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
236{
ead2ceb0 237 consume_skb(skb);
270acefa 238 sk_mem_reclaim_partial(sk);
1da177e4 239}
9d410c79
ED
240EXPORT_SYMBOL(skb_free_datagram);
241
242void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb)
243{
8a74ad60
ED
244 bool slow;
245
93bb64ea
ED
246 if (likely(atomic_read(&skb->users) == 1))
247 smp_rmb();
248 else if (likely(!atomic_dec_and_test(&skb->users)))
249 return;
250
8a74ad60 251 slow = lock_sock_fast(sk);
4b0b72f7
ED
252 skb_orphan(skb);
253 sk_mem_reclaim_partial(sk);
8a74ad60 254 unlock_sock_fast(sk, slow);
4b0b72f7 255
93bb64ea
ED
256 /* skb is now orphaned, can be freed outside of locked section */
257 __kfree_skb(skb);
9d410c79
ED
258}
259EXPORT_SYMBOL(skb_free_datagram_locked);
1da177e4 260
3305b80c
HX
261/**
262 * skb_kill_datagram - Free a datagram skbuff forcibly
263 * @sk: socket
264 * @skb: datagram skbuff
265 * @flags: MSG_ flags
266 *
267 * This function frees a datagram skbuff that was received by
268 * skb_recv_datagram. The flags argument must match the one
269 * used for skb_recv_datagram.
270 *
271 * If the MSG_PEEK flag is set, and the packet is still on the
272 * receive queue of the socket, it will be taken off the queue
273 * before it is freed.
274 *
275 * This function currently only disables BH when acquiring the
276 * sk_receive_queue lock. Therefore it must not be used in a
277 * context where that lock is acquired in an IRQ context.
27ab2568
HX
278 *
279 * It returns 0 if the packet was removed by us.
3305b80c
HX
280 */
281
27ab2568 282int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
3305b80c 283{
27ab2568
HX
284 int err = 0;
285
3305b80c 286 if (flags & MSG_PEEK) {
27ab2568 287 err = -ENOENT;
3305b80c
HX
288 spin_lock_bh(&sk->sk_receive_queue.lock);
289 if (skb == skb_peek(&sk->sk_receive_queue)) {
290 __skb_unlink(skb, &sk->sk_receive_queue);
291 atomic_dec(&skb->users);
27ab2568 292 err = 0;
3305b80c
HX
293 }
294 spin_unlock_bh(&sk->sk_receive_queue.lock);
295 }
296
61de71c6 297 kfree_skb(skb);
8edf19c2 298 atomic_inc(&sk->sk_drops);
61de71c6
JD
299 sk_mem_reclaim_partial(sk);
300
27ab2568 301 return err;
3305b80c 302}
3305b80c
HX
303EXPORT_SYMBOL(skb_kill_datagram);
304
1da177e4
LT
305/**
306 * skb_copy_datagram_iovec - Copy a datagram to an iovec.
4dc3b16b
PP
307 * @skb: buffer to copy
308 * @offset: offset in the buffer to start copying from
67be2dd1 309 * @to: io vector to copy to
4dc3b16b 310 * @len: amount of data to copy from buffer to iovec
1da177e4
LT
311 *
312 * Note: the iovec is modified during the copy.
313 */
314int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
315 struct iovec *to, int len)
316{
1a028e50
DM
317 int start = skb_headlen(skb);
318 int i, copy = start - offset;
5b1a002a 319 struct sk_buff *frag_iter;
c75d721c 320
e9b3cc1b
NH
321 trace_skb_copy_datagram_iovec(skb, len);
322
b4d9eda0
DM
323 /* Copy header. */
324 if (copy > 0) {
325 if (copy > len)
326 copy = len;
327 if (memcpy_toiovec(to, skb->data + offset, copy))
328 goto fault;
329 if ((len -= copy) == 0)
330 return 0;
331 offset += copy;
332 }
c75d721c 333
b4d9eda0
DM
334 /* Copy paged appendix. Hmm... why does this look so complicated? */
335 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1a028e50 336 int end;
9e903e08 337 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1da177e4 338
547b792c 339 WARN_ON(start > offset + len);
1a028e50 340
9e903e08 341 end = start + skb_frag_size(frag);
b4d9eda0
DM
342 if ((copy = end - offset) > 0) {
343 int err;
344 u8 *vaddr;
ea2ab693 345 struct page *page = skb_frag_page(frag);
1da177e4
LT
346
347 if (copy > len)
348 copy = len;
b4d9eda0 349 vaddr = kmap(page);
1a028e50
DM
350 err = memcpy_toiovec(to, vaddr + frag->page_offset +
351 offset - start, copy);
b4d9eda0 352 kunmap(page);
1da177e4
LT
353 if (err)
354 goto fault;
355 if (!(len -= copy))
356 return 0;
357 offset += copy;
358 }
1a028e50 359 start = end;
1da177e4 360 }
b4d9eda0 361
5b1a002a
DM
362 skb_walk_frags(skb, frag_iter) {
363 int end;
364
365 WARN_ON(start > offset + len);
366
367 end = start + frag_iter->len;
368 if ((copy = end - offset) > 0) {
369 if (copy > len)
370 copy = len;
371 if (skb_copy_datagram_iovec(frag_iter,
372 offset - start,
373 to, copy))
374 goto fault;
375 if ((len -= copy) == 0)
376 return 0;
377 offset += copy;
b4d9eda0 378 }
5b1a002a 379 start = end;
1da177e4 380 }
b4d9eda0
DM
381 if (!len)
382 return 0;
383
1da177e4
LT
384fault:
385 return -EFAULT;
386}
9e34a5b5 387EXPORT_SYMBOL(skb_copy_datagram_iovec);
1da177e4 388
0a1ec07a
MT
389/**
390 * skb_copy_datagram_const_iovec - Copy a datagram to an iovec.
391 * @skb: buffer to copy
392 * @offset: offset in the buffer to start copying from
393 * @to: io vector to copy to
394 * @to_offset: offset in the io vector to start copying to
395 * @len: amount of data to copy from buffer to iovec
396 *
397 * Returns 0 or -EFAULT.
398 * Note: the iovec is not modified during the copy.
399 */
400int skb_copy_datagram_const_iovec(const struct sk_buff *skb, int offset,
401 const struct iovec *to, int to_offset,
402 int len)
403{
404 int start = skb_headlen(skb);
405 int i, copy = start - offset;
5b1a002a 406 struct sk_buff *frag_iter;
0a1ec07a
MT
407
408 /* Copy header. */
409 if (copy > 0) {
410 if (copy > len)
411 copy = len;
412 if (memcpy_toiovecend(to, skb->data + offset, to_offset, copy))
413 goto fault;
414 if ((len -= copy) == 0)
415 return 0;
416 offset += copy;
417 to_offset += copy;
418 }
419
420 /* Copy paged appendix. Hmm... why does this look so complicated? */
421 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
422 int end;
9e903e08 423 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
0a1ec07a
MT
424
425 WARN_ON(start > offset + len);
426
9e903e08 427 end = start + skb_frag_size(frag);
0a1ec07a
MT
428 if ((copy = end - offset) > 0) {
429 int err;
430 u8 *vaddr;
ea2ab693 431 struct page *page = skb_frag_page(frag);
0a1ec07a
MT
432
433 if (copy > len)
434 copy = len;
435 vaddr = kmap(page);
436 err = memcpy_toiovecend(to, vaddr + frag->page_offset +
437 offset - start, to_offset, copy);
438 kunmap(page);
439 if (err)
440 goto fault;
441 if (!(len -= copy))
442 return 0;
443 offset += copy;
444 to_offset += copy;
445 }
446 start = end;
447 }
448
5b1a002a
DM
449 skb_walk_frags(skb, frag_iter) {
450 int end;
451
452 WARN_ON(start > offset + len);
453
454 end = start + frag_iter->len;
455 if ((copy = end - offset) > 0) {
456 if (copy > len)
457 copy = len;
458 if (skb_copy_datagram_const_iovec(frag_iter,
459 offset - start,
460 to, to_offset,
461 copy))
462 goto fault;
463 if ((len -= copy) == 0)
464 return 0;
465 offset += copy;
466 to_offset += copy;
0a1ec07a 467 }
5b1a002a 468 start = end;
0a1ec07a
MT
469 }
470 if (!len)
471 return 0;
472
473fault:
474 return -EFAULT;
475}
476EXPORT_SYMBOL(skb_copy_datagram_const_iovec);
477
db543c1f
RR
478/**
479 * skb_copy_datagram_from_iovec - Copy a datagram from an iovec.
480 * @skb: buffer to copy
481 * @offset: offset in the buffer to start copying to
482 * @from: io vector to copy to
6f26c9a7 483 * @from_offset: offset in the io vector to start copying from
db543c1f
RR
484 * @len: amount of data to copy to buffer from iovec
485 *
486 * Returns 0 or -EFAULT.
6f26c9a7 487 * Note: the iovec is not modified during the copy.
db543c1f
RR
488 */
489int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
6f26c9a7
MT
490 const struct iovec *from, int from_offset,
491 int len)
db543c1f
RR
492{
493 int start = skb_headlen(skb);
494 int i, copy = start - offset;
5b1a002a 495 struct sk_buff *frag_iter;
db543c1f
RR
496
497 /* Copy header. */
498 if (copy > 0) {
499 if (copy > len)
500 copy = len;
d2d27bfd
SS
501 if (memcpy_fromiovecend(skb->data + offset, from, from_offset,
502 copy))
db543c1f
RR
503 goto fault;
504 if ((len -= copy) == 0)
505 return 0;
506 offset += copy;
6f26c9a7 507 from_offset += copy;
db543c1f
RR
508 }
509
510 /* Copy paged appendix. Hmm... why does this look so complicated? */
511 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
512 int end;
9e903e08 513 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
db543c1f
RR
514
515 WARN_ON(start > offset + len);
516
9e903e08 517 end = start + skb_frag_size(frag);
db543c1f
RR
518 if ((copy = end - offset) > 0) {
519 int err;
520 u8 *vaddr;
ea2ab693 521 struct page *page = skb_frag_page(frag);
db543c1f
RR
522
523 if (copy > len)
524 copy = len;
525 vaddr = kmap(page);
6f26c9a7
MT
526 err = memcpy_fromiovecend(vaddr + frag->page_offset +
527 offset - start,
528 from, from_offset, copy);
db543c1f
RR
529 kunmap(page);
530 if (err)
531 goto fault;
532
533 if (!(len -= copy))
534 return 0;
535 offset += copy;
6f26c9a7 536 from_offset += copy;
db543c1f
RR
537 }
538 start = end;
539 }
540
5b1a002a
DM
541 skb_walk_frags(skb, frag_iter) {
542 int end;
543
544 WARN_ON(start > offset + len);
545
546 end = start + frag_iter->len;
547 if ((copy = end - offset) > 0) {
548 if (copy > len)
549 copy = len;
550 if (skb_copy_datagram_from_iovec(frag_iter,
551 offset - start,
552 from,
553 from_offset,
554 copy))
555 goto fault;
556 if ((len -= copy) == 0)
557 return 0;
558 offset += copy;
559 from_offset += copy;
db543c1f 560 }
5b1a002a 561 start = end;
db543c1f
RR
562 }
563 if (!len)
564 return 0;
565
566fault:
567 return -EFAULT;
568}
569EXPORT_SYMBOL(skb_copy_datagram_from_iovec);
570
1da177e4
LT
571static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
572 u8 __user *to, int len,
5084205f 573 __wsum *csump)
1da177e4 574{
1a028e50 575 int start = skb_headlen(skb);
1a028e50 576 int i, copy = start - offset;
5b1a002a
DM
577 struct sk_buff *frag_iter;
578 int pos = 0;
1da177e4
LT
579
580 /* Copy header. */
581 if (copy > 0) {
582 int err = 0;
583 if (copy > len)
584 copy = len;
585 *csump = csum_and_copy_to_user(skb->data + offset, to, copy,
586 *csump, &err);
587 if (err)
588 goto fault;
589 if ((len -= copy) == 0)
590 return 0;
591 offset += copy;
592 to += copy;
593 pos = copy;
594 }
595
596 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1a028e50 597 int end;
9e903e08 598 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1da177e4 599
547b792c 600 WARN_ON(start > offset + len);
1a028e50 601
9e903e08 602 end = start + skb_frag_size(frag);
1da177e4 603 if ((copy = end - offset) > 0) {
5084205f 604 __wsum csum2;
1da177e4
LT
605 int err = 0;
606 u8 *vaddr;
ea2ab693 607 struct page *page = skb_frag_page(frag);
1da177e4
LT
608
609 if (copy > len)
610 copy = len;
611 vaddr = kmap(page);
612 csum2 = csum_and_copy_to_user(vaddr +
1a028e50
DM
613 frag->page_offset +
614 offset - start,
1da177e4
LT
615 to, copy, 0, &err);
616 kunmap(page);
617 if (err)
618 goto fault;
619 *csump = csum_block_add(*csump, csum2, pos);
620 if (!(len -= copy))
621 return 0;
622 offset += copy;
623 to += copy;
624 pos += copy;
625 }
1a028e50 626 start = end;
1da177e4
LT
627 }
628
5b1a002a
DM
629 skb_walk_frags(skb, frag_iter) {
630 int end;
631
632 WARN_ON(start > offset + len);
633
634 end = start + frag_iter->len;
635 if ((copy = end - offset) > 0) {
636 __wsum csum2 = 0;
637 if (copy > len)
638 copy = len;
639 if (skb_copy_and_csum_datagram(frag_iter,
640 offset - start,
641 to, copy,
642 &csum2))
643 goto fault;
644 *csump = csum_block_add(*csump, csum2, pos);
645 if ((len -= copy) == 0)
646 return 0;
647 offset += copy;
648 to += copy;
649 pos += copy;
1da177e4 650 }
5b1a002a 651 start = end;
1da177e4
LT
652 }
653 if (!len)
654 return 0;
655
656fault:
657 return -EFAULT;
658}
659
759e5d00 660__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
fb286bb2 661{
d3bc23e7 662 __sum16 sum;
fb286bb2 663
759e5d00 664 sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
fb286bb2 665 if (likely(!sum)) {
84fa7933 666 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
fb286bb2
HX
667 netdev_rx_csum_fault(skb->dev);
668 skb->ip_summed = CHECKSUM_UNNECESSARY;
669 }
670 return sum;
671}
759e5d00
HX
672EXPORT_SYMBOL(__skb_checksum_complete_head);
673
674__sum16 __skb_checksum_complete(struct sk_buff *skb)
675{
676 return __skb_checksum_complete_head(skb, skb->len);
677}
fb286bb2
HX
678EXPORT_SYMBOL(__skb_checksum_complete);
679
1da177e4
LT
680/**
681 * skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec.
4dc3b16b
PP
682 * @skb: skbuff
683 * @hlen: hardware length
67be2dd1 684 * @iov: io vector
4ec93edb 685 *
1da177e4
LT
686 * Caller _must_ check that skb will fit to this iovec.
687 *
688 * Returns: 0 - success.
689 * -EINVAL - checksum failure.
690 * -EFAULT - fault during copy. Beware, in this case iovec
691 * can be modified!
692 */
fb286bb2 693int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1da177e4
LT
694 int hlen, struct iovec *iov)
695{
d3bc23e7 696 __wsum csum;
1da177e4
LT
697 int chunk = skb->len - hlen;
698
ef8aef55
HX
699 if (!chunk)
700 return 0;
701
1da177e4
LT
702 /* Skip filled elements.
703 * Pretty silly, look at memcpy_toiovec, though 8)
704 */
705 while (!iov->iov_len)
706 iov++;
707
708 if (iov->iov_len < chunk) {
fb286bb2 709 if (__skb_checksum_complete(skb))
1da177e4
LT
710 goto csum_error;
711 if (skb_copy_datagram_iovec(skb, hlen, iov, chunk))
712 goto fault;
713 } else {
714 csum = csum_partial(skb->data, hlen, skb->csum);
715 if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base,
716 chunk, &csum))
717 goto fault;
d3bc23e7 718 if (csum_fold(csum))
1da177e4 719 goto csum_error;
84fa7933 720 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
fb286bb2 721 netdev_rx_csum_fault(skb->dev);
1da177e4
LT
722 iov->iov_len -= chunk;
723 iov->iov_base += chunk;
724 }
725 return 0;
726csum_error:
727 return -EINVAL;
728fault:
729 return -EFAULT;
730}
9e34a5b5 731EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec);
1da177e4
LT
732
733/**
734 * datagram_poll - generic datagram poll
4dc3b16b
PP
735 * @file: file struct
736 * @sock: socket
737 * @wait: poll table
1da177e4
LT
738 *
739 * Datagram poll: Again totally generic. This also handles
740 * sequenced packet sockets providing the socket receive queue
741 * is only ever holding data ready to receive.
742 *
743 * Note: when you _don't_ use this routine for this protocol,
744 * and you use a different write policy from sock_writeable()
745 * then please supply your own write_space callback.
746 */
747unsigned int datagram_poll(struct file *file, struct socket *sock,
748 poll_table *wait)
749{
750 struct sock *sk = sock->sk;
751 unsigned int mask;
752
aa395145 753 sock_poll_wait(file, sk_sleep(sk), wait);
1da177e4
LT
754 mask = 0;
755
756 /* exceptional events? */
757 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
7d4c04fc 758 mask |= POLLERR |
8facd5fb 759 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
7d4c04fc 760
f348d70a 761 if (sk->sk_shutdown & RCV_SHUTDOWN)
db40980f 762 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
1da177e4
LT
763 if (sk->sk_shutdown == SHUTDOWN_MASK)
764 mask |= POLLHUP;
765
766 /* readable? */
db40980f 767 if (!skb_queue_empty(&sk->sk_receive_queue))
1da177e4
LT
768 mask |= POLLIN | POLLRDNORM;
769
770 /* Connection-based need to check for termination and startup */
771 if (connection_based(sk)) {
772 if (sk->sk_state == TCP_CLOSE)
773 mask |= POLLHUP;
774 /* connection hasn't started yet? */
775 if (sk->sk_state == TCP_SYN_SENT)
776 return mask;
777 }
778
779 /* writable? */
780 if (sock_writeable(sk))
781 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
782 else
783 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
784
785 return mask;
786}
1da177e4 787EXPORT_SYMBOL(datagram_poll);