Commit | Line | Data |
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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 | * | |
12 | * Authors: Alan Cox <alan@redhat.com>. (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> | |
1da177e4 LT |
46 | #include <linux/netdevice.h> |
47 | #include <linux/rtnetlink.h> | |
48 | #include <linux/poll.h> | |
49 | #include <linux/highmem.h> | |
3305b80c | 50 | #include <linux/spinlock.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> | |
1da177e4 LT |
58 | |
59 | /* | |
60 | * Is a socket 'connection oriented' ? | |
61 | */ | |
62 | static inline int connection_based(struct sock *sk) | |
63 | { | |
64 | return sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM; | |
65 | } | |
66 | ||
67 | /* | |
68 | * Wait for a packet.. | |
69 | */ | |
70 | static int wait_for_packet(struct sock *sk, int *err, long *timeo_p) | |
71 | { | |
72 | int error; | |
73 | DEFINE_WAIT(wait); | |
74 | ||
75 | prepare_to_wait_exclusive(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); | |
76 | ||
77 | /* Socket errors? */ | |
78 | error = sock_error(sk); | |
79 | if (error) | |
80 | goto out_err; | |
81 | ||
82 | if (!skb_queue_empty(&sk->sk_receive_queue)) | |
83 | goto out; | |
84 | ||
85 | /* Socket shut down? */ | |
86 | if (sk->sk_shutdown & RCV_SHUTDOWN) | |
87 | goto out_noerr; | |
88 | ||
89 | /* Sequenced packets can come disconnected. | |
90 | * If so we report the problem | |
91 | */ | |
92 | error = -ENOTCONN; | |
93 | if (connection_based(sk) && | |
94 | !(sk->sk_state == TCP_ESTABLISHED || sk->sk_state == TCP_LISTEN)) | |
95 | goto out_err; | |
96 | ||
97 | /* handle signals */ | |
98 | if (signal_pending(current)) | |
99 | goto interrupted; | |
100 | ||
101 | error = 0; | |
102 | *timeo_p = schedule_timeout(*timeo_p); | |
103 | out: | |
104 | finish_wait(sk->sk_sleep, &wait); | |
105 | return error; | |
106 | interrupted: | |
107 | error = sock_intr_errno(*timeo_p); | |
108 | out_err: | |
109 | *err = error; | |
110 | goto out; | |
111 | out_noerr: | |
112 | *err = 0; | |
113 | error = 1; | |
114 | goto out; | |
115 | } | |
116 | ||
117 | /** | |
118 | * skb_recv_datagram - Receive a datagram skbuff | |
4dc3b16b PP |
119 | * @sk: socket |
120 | * @flags: MSG_ flags | |
121 | * @noblock: blocking operation? | |
122 | * @err: error code returned | |
1da177e4 LT |
123 | * |
124 | * Get a datagram skbuff, understands the peeking, nonblocking wakeups | |
125 | * and possible races. This replaces identical code in packet, raw and | |
126 | * udp, as well as the IPX AX.25 and Appletalk. It also finally fixes | |
127 | * the long standing peek and read race for datagram sockets. If you | |
128 | * alter this routine remember it must be re-entrant. | |
129 | * | |
130 | * This function will lock the socket if a skb is returned, so the caller | |
131 | * needs to unlock the socket in that case (usually by calling | |
132 | * skb_free_datagram) | |
133 | * | |
134 | * * It does not lock socket since today. This function is | |
135 | * * free of race conditions. This measure should/can improve | |
136 | * * significantly datagram socket latencies at high loads, | |
137 | * * when data copying to user space takes lots of time. | |
138 | * * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet | |
139 | * * 8) Great win.) | |
140 | * * --ANK (980729) | |
141 | * | |
142 | * The order of the tests when we find no data waiting are specified | |
143 | * quite explicitly by POSIX 1003.1g, don't change them without having | |
144 | * the standard around please. | |
145 | */ | |
146 | struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, | |
147 | int noblock, int *err) | |
148 | { | |
149 | struct sk_buff *skb; | |
150 | long timeo; | |
151 | /* | |
152 | * Caller is allowed not to check sk->sk_err before skb_recv_datagram() | |
153 | */ | |
154 | int error = sock_error(sk); | |
155 | ||
156 | if (error) | |
157 | goto no_packet; | |
158 | ||
159 | timeo = sock_rcvtimeo(sk, noblock); | |
160 | ||
161 | do { | |
162 | /* Again only user level code calls this function, so nothing | |
163 | * interrupt level will suddenly eat the receive_queue. | |
164 | * | |
165 | * Look at current nfs client by the way... | |
166 | * However, this function was corrent in any case. 8) | |
167 | */ | |
168 | if (flags & MSG_PEEK) { | |
169 | unsigned long cpu_flags; | |
170 | ||
171 | spin_lock_irqsave(&sk->sk_receive_queue.lock, | |
172 | cpu_flags); | |
173 | skb = skb_peek(&sk->sk_receive_queue); | |
174 | if (skb) | |
175 | atomic_inc(&skb->users); | |
176 | spin_unlock_irqrestore(&sk->sk_receive_queue.lock, | |
177 | cpu_flags); | |
178 | } else | |
179 | skb = skb_dequeue(&sk->sk_receive_queue); | |
180 | ||
181 | if (skb) | |
182 | return skb; | |
183 | ||
184 | /* User doesn't want to wait */ | |
185 | error = -EAGAIN; | |
186 | if (!timeo) | |
187 | goto no_packet; | |
188 | ||
189 | } while (!wait_for_packet(sk, err, &timeo)); | |
190 | ||
191 | return NULL; | |
192 | ||
193 | no_packet: | |
194 | *err = error; | |
195 | return NULL; | |
196 | } | |
197 | ||
198 | void skb_free_datagram(struct sock *sk, struct sk_buff *skb) | |
199 | { | |
200 | kfree_skb(skb); | |
201 | } | |
202 | ||
3305b80c HX |
203 | /** |
204 | * skb_kill_datagram - Free a datagram skbuff forcibly | |
205 | * @sk: socket | |
206 | * @skb: datagram skbuff | |
207 | * @flags: MSG_ flags | |
208 | * | |
209 | * This function frees a datagram skbuff that was received by | |
210 | * skb_recv_datagram. The flags argument must match the one | |
211 | * used for skb_recv_datagram. | |
212 | * | |
213 | * If the MSG_PEEK flag is set, and the packet is still on the | |
214 | * receive queue of the socket, it will be taken off the queue | |
215 | * before it is freed. | |
216 | * | |
217 | * This function currently only disables BH when acquiring the | |
218 | * sk_receive_queue lock. Therefore it must not be used in a | |
219 | * context where that lock is acquired in an IRQ context. | |
220 | */ | |
221 | ||
222 | void skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags) | |
223 | { | |
224 | if (flags & MSG_PEEK) { | |
225 | spin_lock_bh(&sk->sk_receive_queue.lock); | |
226 | if (skb == skb_peek(&sk->sk_receive_queue)) { | |
227 | __skb_unlink(skb, &sk->sk_receive_queue); | |
228 | atomic_dec(&skb->users); | |
229 | } | |
230 | spin_unlock_bh(&sk->sk_receive_queue.lock); | |
231 | } | |
232 | ||
233 | kfree_skb(skb); | |
234 | } | |
235 | ||
236 | EXPORT_SYMBOL(skb_kill_datagram); | |
237 | ||
1da177e4 LT |
238 | /** |
239 | * skb_copy_datagram_iovec - Copy a datagram to an iovec. | |
4dc3b16b PP |
240 | * @skb: buffer to copy |
241 | * @offset: offset in the buffer to start copying from | |
67be2dd1 | 242 | * @to: io vector to copy to |
4dc3b16b | 243 | * @len: amount of data to copy from buffer to iovec |
1da177e4 LT |
244 | * |
245 | * Note: the iovec is modified during the copy. | |
246 | */ | |
247 | int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset, | |
248 | struct iovec *to, int len) | |
249 | { | |
b4d9eda0 DM |
250 | int start = skb_headlen(skb); |
251 | int i, copy = start - offset; | |
c75d721c | 252 | |
b4d9eda0 DM |
253 | /* Copy header. */ |
254 | if (copy > 0) { | |
255 | if (copy > len) | |
256 | copy = len; | |
257 | if (memcpy_toiovec(to, skb->data + offset, copy)) | |
258 | goto fault; | |
259 | if ((len -= copy) == 0) | |
260 | return 0; | |
261 | offset += copy; | |
262 | } | |
c75d721c | 263 | |
b4d9eda0 DM |
264 | /* Copy paged appendix. Hmm... why does this look so complicated? */ |
265 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { | |
266 | int end; | |
1da177e4 | 267 | |
b4d9eda0 | 268 | BUG_TRAP(start <= offset + len); |
1da177e4 | 269 | |
b4d9eda0 DM |
270 | end = start + skb_shinfo(skb)->frags[i].size; |
271 | if ((copy = end - offset) > 0) { | |
272 | int err; | |
273 | u8 *vaddr; | |
274 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; | |
275 | struct page *page = frag->page; | |
1da177e4 LT |
276 | |
277 | if (copy > len) | |
278 | copy = len; | |
b4d9eda0 DM |
279 | vaddr = kmap(page); |
280 | err = memcpy_toiovec(to, vaddr + frag->page_offset + | |
281 | offset - start, copy); | |
282 | kunmap(page); | |
1da177e4 LT |
283 | if (err) |
284 | goto fault; | |
285 | if (!(len -= copy)) | |
286 | return 0; | |
287 | offset += copy; | |
288 | } | |
b4d9eda0 | 289 | start = end; |
1da177e4 | 290 | } |
b4d9eda0 DM |
291 | |
292 | if (skb_shinfo(skb)->frag_list) { | |
293 | struct sk_buff *list = skb_shinfo(skb)->frag_list; | |
294 | ||
295 | for (; list; list = list->next) { | |
296 | int end; | |
297 | ||
298 | BUG_TRAP(start <= offset + len); | |
299 | ||
300 | end = start + list->len; | |
301 | if ((copy = end - offset) > 0) { | |
302 | if (copy > len) | |
303 | copy = len; | |
304 | if (skb_copy_datagram_iovec(list, | |
305 | offset - start, | |
306 | to, copy)) | |
307 | goto fault; | |
308 | if ((len -= copy) == 0) | |
309 | return 0; | |
310 | offset += copy; | |
311 | } | |
312 | start = end; | |
313 | } | |
1da177e4 | 314 | } |
b4d9eda0 DM |
315 | if (!len) |
316 | return 0; | |
317 | ||
1da177e4 LT |
318 | fault: |
319 | return -EFAULT; | |
320 | } | |
321 | ||
322 | static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, | |
323 | u8 __user *to, int len, | |
5084205f | 324 | __wsum *csump) |
1da177e4 LT |
325 | { |
326 | int start = skb_headlen(skb); | |
327 | int pos = 0; | |
328 | int i, copy = start - offset; | |
329 | ||
330 | /* Copy header. */ | |
331 | if (copy > 0) { | |
332 | int err = 0; | |
333 | if (copy > len) | |
334 | copy = len; | |
335 | *csump = csum_and_copy_to_user(skb->data + offset, to, copy, | |
336 | *csump, &err); | |
337 | if (err) | |
338 | goto fault; | |
339 | if ((len -= copy) == 0) | |
340 | return 0; | |
341 | offset += copy; | |
342 | to += copy; | |
343 | pos = copy; | |
344 | } | |
345 | ||
346 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { | |
347 | int end; | |
348 | ||
349 | BUG_TRAP(start <= offset + len); | |
350 | ||
351 | end = start + skb_shinfo(skb)->frags[i].size; | |
352 | if ((copy = end - offset) > 0) { | |
5084205f | 353 | __wsum csum2; |
1da177e4 LT |
354 | int err = 0; |
355 | u8 *vaddr; | |
356 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; | |
357 | struct page *page = frag->page; | |
358 | ||
359 | if (copy > len) | |
360 | copy = len; | |
361 | vaddr = kmap(page); | |
362 | csum2 = csum_and_copy_to_user(vaddr + | |
363 | frag->page_offset + | |
364 | offset - start, | |
365 | to, copy, 0, &err); | |
366 | kunmap(page); | |
367 | if (err) | |
368 | goto fault; | |
369 | *csump = csum_block_add(*csump, csum2, pos); | |
370 | if (!(len -= copy)) | |
371 | return 0; | |
372 | offset += copy; | |
373 | to += copy; | |
374 | pos += copy; | |
375 | } | |
376 | start = end; | |
377 | } | |
378 | ||
379 | if (skb_shinfo(skb)->frag_list) { | |
380 | struct sk_buff *list = skb_shinfo(skb)->frag_list; | |
381 | ||
382 | for (; list; list=list->next) { | |
383 | int end; | |
384 | ||
385 | BUG_TRAP(start <= offset + len); | |
386 | ||
387 | end = start + list->len; | |
388 | if ((copy = end - offset) > 0) { | |
5084205f | 389 | __wsum csum2 = 0; |
1da177e4 LT |
390 | if (copy > len) |
391 | copy = len; | |
392 | if (skb_copy_and_csum_datagram(list, | |
393 | offset - start, | |
394 | to, copy, | |
395 | &csum2)) | |
396 | goto fault; | |
397 | *csump = csum_block_add(*csump, csum2, pos); | |
398 | if ((len -= copy) == 0) | |
399 | return 0; | |
400 | offset += copy; | |
401 | to += copy; | |
402 | pos += copy; | |
403 | } | |
404 | start = end; | |
405 | } | |
406 | } | |
407 | if (!len) | |
408 | return 0; | |
409 | ||
410 | fault: | |
411 | return -EFAULT; | |
412 | } | |
413 | ||
b51655b9 | 414 | __sum16 __skb_checksum_complete(struct sk_buff *skb) |
fb286bb2 | 415 | { |
d3bc23e7 | 416 | __sum16 sum; |
fb286bb2 | 417 | |
d3bc23e7 | 418 | sum = csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); |
fb286bb2 | 419 | if (likely(!sum)) { |
84fa7933 | 420 | if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) |
fb286bb2 HX |
421 | netdev_rx_csum_fault(skb->dev); |
422 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
423 | } | |
424 | return sum; | |
425 | } | |
426 | EXPORT_SYMBOL(__skb_checksum_complete); | |
427 | ||
1da177e4 LT |
428 | /** |
429 | * skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec. | |
4dc3b16b PP |
430 | * @skb: skbuff |
431 | * @hlen: hardware length | |
67be2dd1 | 432 | * @iov: io vector |
4ec93edb | 433 | * |
1da177e4 LT |
434 | * Caller _must_ check that skb will fit to this iovec. |
435 | * | |
436 | * Returns: 0 - success. | |
437 | * -EINVAL - checksum failure. | |
438 | * -EFAULT - fault during copy. Beware, in this case iovec | |
439 | * can be modified! | |
440 | */ | |
fb286bb2 | 441 | int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, |
1da177e4 LT |
442 | int hlen, struct iovec *iov) |
443 | { | |
d3bc23e7 | 444 | __wsum csum; |
1da177e4 LT |
445 | int chunk = skb->len - hlen; |
446 | ||
447 | /* Skip filled elements. | |
448 | * Pretty silly, look at memcpy_toiovec, though 8) | |
449 | */ | |
450 | while (!iov->iov_len) | |
451 | iov++; | |
452 | ||
453 | if (iov->iov_len < chunk) { | |
fb286bb2 | 454 | if (__skb_checksum_complete(skb)) |
1da177e4 LT |
455 | goto csum_error; |
456 | if (skb_copy_datagram_iovec(skb, hlen, iov, chunk)) | |
457 | goto fault; | |
458 | } else { | |
459 | csum = csum_partial(skb->data, hlen, skb->csum); | |
460 | if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base, | |
461 | chunk, &csum)) | |
462 | goto fault; | |
d3bc23e7 | 463 | if (csum_fold(csum)) |
1da177e4 | 464 | goto csum_error; |
84fa7933 | 465 | if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) |
fb286bb2 | 466 | netdev_rx_csum_fault(skb->dev); |
1da177e4 LT |
467 | iov->iov_len -= chunk; |
468 | iov->iov_base += chunk; | |
469 | } | |
470 | return 0; | |
471 | csum_error: | |
472 | return -EINVAL; | |
473 | fault: | |
474 | return -EFAULT; | |
475 | } | |
476 | ||
477 | /** | |
478 | * datagram_poll - generic datagram poll | |
4dc3b16b PP |
479 | * @file: file struct |
480 | * @sock: socket | |
481 | * @wait: poll table | |
1da177e4 LT |
482 | * |
483 | * Datagram poll: Again totally generic. This also handles | |
484 | * sequenced packet sockets providing the socket receive queue | |
485 | * is only ever holding data ready to receive. | |
486 | * | |
487 | * Note: when you _don't_ use this routine for this protocol, | |
488 | * and you use a different write policy from sock_writeable() | |
489 | * then please supply your own write_space callback. | |
490 | */ | |
491 | unsigned int datagram_poll(struct file *file, struct socket *sock, | |
492 | poll_table *wait) | |
493 | { | |
494 | struct sock *sk = sock->sk; | |
495 | unsigned int mask; | |
496 | ||
497 | poll_wait(file, sk->sk_sleep, wait); | |
498 | mask = 0; | |
499 | ||
500 | /* exceptional events? */ | |
501 | if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) | |
502 | mask |= POLLERR; | |
f348d70a DL |
503 | if (sk->sk_shutdown & RCV_SHUTDOWN) |
504 | mask |= POLLRDHUP; | |
1da177e4 LT |
505 | if (sk->sk_shutdown == SHUTDOWN_MASK) |
506 | mask |= POLLHUP; | |
507 | ||
508 | /* readable? */ | |
509 | if (!skb_queue_empty(&sk->sk_receive_queue) || | |
510 | (sk->sk_shutdown & RCV_SHUTDOWN)) | |
511 | mask |= POLLIN | POLLRDNORM; | |
512 | ||
513 | /* Connection-based need to check for termination and startup */ | |
514 | if (connection_based(sk)) { | |
515 | if (sk->sk_state == TCP_CLOSE) | |
516 | mask |= POLLHUP; | |
517 | /* connection hasn't started yet? */ | |
518 | if (sk->sk_state == TCP_SYN_SENT) | |
519 | return mask; | |
520 | } | |
521 | ||
522 | /* writable? */ | |
523 | if (sock_writeable(sk)) | |
524 | mask |= POLLOUT | POLLWRNORM | POLLWRBAND; | |
525 | else | |
526 | set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); | |
527 | ||
528 | return mask; | |
529 | } | |
530 | ||
531 | EXPORT_SYMBOL(datagram_poll); | |
532 | EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec); | |
533 | EXPORT_SYMBOL(skb_copy_datagram_iovec); | |
534 | EXPORT_SYMBOL(skb_free_datagram); | |
535 | EXPORT_SYMBOL(skb_recv_datagram); |