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[I/OAT]: TCP recv offload to I/OAT
[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
21 *
22 * Fixes:
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
27 * (tcp_err()).
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
38 * unknown sockets.
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
41 * syn rule wrong]
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
47 * escape still
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
51 * facilities
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
56 * bit to skb ops.
57 * Alan Cox : Tidied tcp_data to avoid a potential
58 * nasty.
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
70 * sockets.
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
74 * state ack error.
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
79 * fixes
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
85 * completely
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
93 * (not yet usable)
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
106 * all cases.
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
111 * works now.
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
113 * BSD api.
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
121 * fixed ports.
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
127 * socket close.
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
132 * accept.
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
143 * close.
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
149 * comments.
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
157 * resemble the RFC.
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
162 * generates them.
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
175 * but it's a start!
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
196 * improvement.
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
209 *
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
214 *
215 * Description of States:
216 *
217 * TCP_SYN_SENT sent a connection request, waiting for ack
218 *
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
221 *
222 * TCP_ESTABLISHED connection established
223 *
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
226 *
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * to shutdown
229 *
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
232 *
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
238 *
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
242 *
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
246 *
247 * TCP_CLOSE socket is finished
248 */
249
250 #include <linux/config.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/smp_lock.h>
257 #include <linux/fs.h>
258 #include <linux/random.h>
259 #include <linux/bootmem.h>
260 #include <linux/cache.h>
261
262 #include <net/icmp.h>
263 #include <net/tcp.h>
264 #include <net/xfrm.h>
265 #include <net/ip.h>
266 #include <net/netdma.h>
267
268 #include <asm/uaccess.h>
269 #include <asm/ioctls.h>
270
271 int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
272
273 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
274
275 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
276
277 EXPORT_SYMBOL_GPL(tcp_orphan_count);
278
279 int sysctl_tcp_mem[3] __read_mostly;
280 int sysctl_tcp_wmem[3] __read_mostly;
281 int sysctl_tcp_rmem[3] __read_mostly;
282
283 EXPORT_SYMBOL(sysctl_tcp_mem);
284 EXPORT_SYMBOL(sysctl_tcp_rmem);
285 EXPORT_SYMBOL(sysctl_tcp_wmem);
286
287 atomic_t tcp_memory_allocated; /* Current allocated memory. */
288 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
289
290 EXPORT_SYMBOL(tcp_memory_allocated);
291 EXPORT_SYMBOL(tcp_sockets_allocated);
292
293 /*
294 * Pressure flag: try to collapse.
295 * Technical note: it is used by multiple contexts non atomically.
296 * All the sk_stream_mem_schedule() is of this nature: accounting
297 * is strict, actions are advisory and have some latency.
298 */
299 int tcp_memory_pressure;
300
301 EXPORT_SYMBOL(tcp_memory_pressure);
302
303 void tcp_enter_memory_pressure(void)
304 {
305 if (!tcp_memory_pressure) {
306 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
307 tcp_memory_pressure = 1;
308 }
309 }
310
311 EXPORT_SYMBOL(tcp_enter_memory_pressure);
312
313 /*
314 * Wait for a TCP event.
315 *
316 * Note that we don't need to lock the socket, as the upper poll layers
317 * take care of normal races (between the test and the event) and we don't
318 * go look at any of the socket buffers directly.
319 */
320 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
321 {
322 unsigned int mask;
323 struct sock *sk = sock->sk;
324 struct tcp_sock *tp = tcp_sk(sk);
325
326 poll_wait(file, sk->sk_sleep, wait);
327 if (sk->sk_state == TCP_LISTEN)
328 return inet_csk_listen_poll(sk);
329
330 /* Socket is not locked. We are protected from async events
331 by poll logic and correct handling of state changes
332 made by another threads is impossible in any case.
333 */
334
335 mask = 0;
336 if (sk->sk_err)
337 mask = POLLERR;
338
339 /*
340 * POLLHUP is certainly not done right. But poll() doesn't
341 * have a notion of HUP in just one direction, and for a
342 * socket the read side is more interesting.
343 *
344 * Some poll() documentation says that POLLHUP is incompatible
345 * with the POLLOUT/POLLWR flags, so somebody should check this
346 * all. But careful, it tends to be safer to return too many
347 * bits than too few, and you can easily break real applications
348 * if you don't tell them that something has hung up!
349 *
350 * Check-me.
351 *
352 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
353 * our fs/select.c). It means that after we received EOF,
354 * poll always returns immediately, making impossible poll() on write()
355 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
356 * if and only if shutdown has been made in both directions.
357 * Actually, it is interesting to look how Solaris and DUX
358 * solve this dilemma. I would prefer, if PULLHUP were maskable,
359 * then we could set it on SND_SHUTDOWN. BTW examples given
360 * in Stevens' books assume exactly this behaviour, it explains
361 * why PULLHUP is incompatible with POLLOUT. --ANK
362 *
363 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
364 * blocking on fresh not-connected or disconnected socket. --ANK
365 */
366 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
367 mask |= POLLHUP;
368 if (sk->sk_shutdown & RCV_SHUTDOWN)
369 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
370
371 /* Connected? */
372 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
373 /* Potential race condition. If read of tp below will
374 * escape above sk->sk_state, we can be illegally awaken
375 * in SYN_* states. */
376 if ((tp->rcv_nxt != tp->copied_seq) &&
377 (tp->urg_seq != tp->copied_seq ||
378 tp->rcv_nxt != tp->copied_seq + 1 ||
379 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
380 mask |= POLLIN | POLLRDNORM;
381
382 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
383 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
384 mask |= POLLOUT | POLLWRNORM;
385 } else { /* send SIGIO later */
386 set_bit(SOCK_ASYNC_NOSPACE,
387 &sk->sk_socket->flags);
388 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
389
390 /* Race breaker. If space is freed after
391 * wspace test but before the flags are set,
392 * IO signal will be lost.
393 */
394 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
395 mask |= POLLOUT | POLLWRNORM;
396 }
397 }
398
399 if (tp->urg_data & TCP_URG_VALID)
400 mask |= POLLPRI;
401 }
402 return mask;
403 }
404
405 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
406 {
407 struct tcp_sock *tp = tcp_sk(sk);
408 int answ;
409
410 switch (cmd) {
411 case SIOCINQ:
412 if (sk->sk_state == TCP_LISTEN)
413 return -EINVAL;
414
415 lock_sock(sk);
416 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
417 answ = 0;
418 else if (sock_flag(sk, SOCK_URGINLINE) ||
419 !tp->urg_data ||
420 before(tp->urg_seq, tp->copied_seq) ||
421 !before(tp->urg_seq, tp->rcv_nxt)) {
422 answ = tp->rcv_nxt - tp->copied_seq;
423
424 /* Subtract 1, if FIN is in queue. */
425 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
426 answ -=
427 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
428 } else
429 answ = tp->urg_seq - tp->copied_seq;
430 release_sock(sk);
431 break;
432 case SIOCATMARK:
433 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
434 break;
435 case SIOCOUTQ:
436 if (sk->sk_state == TCP_LISTEN)
437 return -EINVAL;
438
439 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
440 answ = 0;
441 else
442 answ = tp->write_seq - tp->snd_una;
443 break;
444 default:
445 return -ENOIOCTLCMD;
446 };
447
448 return put_user(answ, (int __user *)arg);
449 }
450
451 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
452 {
453 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
454 tp->pushed_seq = tp->write_seq;
455 }
456
457 static inline int forced_push(struct tcp_sock *tp)
458 {
459 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
460 }
461
462 static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
463 struct sk_buff *skb)
464 {
465 skb->csum = 0;
466 TCP_SKB_CB(skb)->seq = tp->write_seq;
467 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
468 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
469 TCP_SKB_CB(skb)->sacked = 0;
470 skb_header_release(skb);
471 __skb_queue_tail(&sk->sk_write_queue, skb);
472 sk_charge_skb(sk, skb);
473 if (!sk->sk_send_head)
474 sk->sk_send_head = skb;
475 if (tp->nonagle & TCP_NAGLE_PUSH)
476 tp->nonagle &= ~TCP_NAGLE_PUSH;
477 }
478
479 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
480 struct sk_buff *skb)
481 {
482 if (flags & MSG_OOB) {
483 tp->urg_mode = 1;
484 tp->snd_up = tp->write_seq;
485 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
486 }
487 }
488
489 static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags,
490 int mss_now, int nonagle)
491 {
492 if (sk->sk_send_head) {
493 struct sk_buff *skb = sk->sk_write_queue.prev;
494 if (!(flags & MSG_MORE) || forced_push(tp))
495 tcp_mark_push(tp, skb);
496 tcp_mark_urg(tp, flags, skb);
497 __tcp_push_pending_frames(sk, tp, mss_now,
498 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
499 }
500 }
501
502 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
503 size_t psize, int flags)
504 {
505 struct tcp_sock *tp = tcp_sk(sk);
506 int mss_now, size_goal;
507 int err;
508 ssize_t copied;
509 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
510
511 /* Wait for a connection to finish. */
512 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
513 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
514 goto out_err;
515
516 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
517
518 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
519 size_goal = tp->xmit_size_goal;
520 copied = 0;
521
522 err = -EPIPE;
523 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
524 goto do_error;
525
526 while (psize > 0) {
527 struct sk_buff *skb = sk->sk_write_queue.prev;
528 struct page *page = pages[poffset / PAGE_SIZE];
529 int copy, i, can_coalesce;
530 int offset = poffset % PAGE_SIZE;
531 int size = min_t(size_t, psize, PAGE_SIZE - offset);
532
533 if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) {
534 new_segment:
535 if (!sk_stream_memory_free(sk))
536 goto wait_for_sndbuf;
537
538 skb = sk_stream_alloc_pskb(sk, 0, 0,
539 sk->sk_allocation);
540 if (!skb)
541 goto wait_for_memory;
542
543 skb_entail(sk, tp, skb);
544 copy = size_goal;
545 }
546
547 if (copy > size)
548 copy = size;
549
550 i = skb_shinfo(skb)->nr_frags;
551 can_coalesce = skb_can_coalesce(skb, i, page, offset);
552 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
553 tcp_mark_push(tp, skb);
554 goto new_segment;
555 }
556 if (!sk_stream_wmem_schedule(sk, copy))
557 goto wait_for_memory;
558
559 if (can_coalesce) {
560 skb_shinfo(skb)->frags[i - 1].size += copy;
561 } else {
562 get_page(page);
563 skb_fill_page_desc(skb, i, page, offset, copy);
564 }
565
566 skb->len += copy;
567 skb->data_len += copy;
568 skb->truesize += copy;
569 sk->sk_wmem_queued += copy;
570 sk->sk_forward_alloc -= copy;
571 skb->ip_summed = CHECKSUM_HW;
572 tp->write_seq += copy;
573 TCP_SKB_CB(skb)->end_seq += copy;
574 skb_shinfo(skb)->tso_segs = 0;
575
576 if (!copied)
577 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
578
579 copied += copy;
580 poffset += copy;
581 if (!(psize -= copy))
582 goto out;
583
584 if (skb->len < mss_now || (flags & MSG_OOB))
585 continue;
586
587 if (forced_push(tp)) {
588 tcp_mark_push(tp, skb);
589 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
590 } else if (skb == sk->sk_send_head)
591 tcp_push_one(sk, mss_now);
592 continue;
593
594 wait_for_sndbuf:
595 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
596 wait_for_memory:
597 if (copied)
598 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
599
600 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
601 goto do_error;
602
603 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
604 size_goal = tp->xmit_size_goal;
605 }
606
607 out:
608 if (copied)
609 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
610 return copied;
611
612 do_error:
613 if (copied)
614 goto out;
615 out_err:
616 return sk_stream_error(sk, flags, err);
617 }
618
619 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
620 size_t size, int flags)
621 {
622 ssize_t res;
623 struct sock *sk = sock->sk;
624
625 #define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
626
627 if (!(sk->sk_route_caps & NETIF_F_SG) ||
628 !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
629 return sock_no_sendpage(sock, page, offset, size, flags);
630
631 #undef TCP_ZC_CSUM_FLAGS
632
633 lock_sock(sk);
634 TCP_CHECK_TIMER(sk);
635 res = do_tcp_sendpages(sk, &page, offset, size, flags);
636 TCP_CHECK_TIMER(sk);
637 release_sock(sk);
638 return res;
639 }
640
641 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
642 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
643
644 static inline int select_size(struct sock *sk, struct tcp_sock *tp)
645 {
646 int tmp = tp->mss_cache;
647
648 if (sk->sk_route_caps & NETIF_F_SG) {
649 if (sk->sk_route_caps & NETIF_F_TSO)
650 tmp = 0;
651 else {
652 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
653
654 if (tmp >= pgbreak &&
655 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
656 tmp = pgbreak;
657 }
658 }
659
660 return tmp;
661 }
662
663 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
664 size_t size)
665 {
666 struct iovec *iov;
667 struct tcp_sock *tp = tcp_sk(sk);
668 struct sk_buff *skb;
669 int iovlen, flags;
670 int mss_now, size_goal;
671 int err, copied;
672 long timeo;
673
674 lock_sock(sk);
675 TCP_CHECK_TIMER(sk);
676
677 flags = msg->msg_flags;
678 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
679
680 /* Wait for a connection to finish. */
681 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
682 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
683 goto out_err;
684
685 /* This should be in poll */
686 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
687
688 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
689 size_goal = tp->xmit_size_goal;
690
691 /* Ok commence sending. */
692 iovlen = msg->msg_iovlen;
693 iov = msg->msg_iov;
694 copied = 0;
695
696 err = -EPIPE;
697 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
698 goto do_error;
699
700 while (--iovlen >= 0) {
701 int seglen = iov->iov_len;
702 unsigned char __user *from = iov->iov_base;
703
704 iov++;
705
706 while (seglen > 0) {
707 int copy;
708
709 skb = sk->sk_write_queue.prev;
710
711 if (!sk->sk_send_head ||
712 (copy = size_goal - skb->len) <= 0) {
713
714 new_segment:
715 /* Allocate new segment. If the interface is SG,
716 * allocate skb fitting to single page.
717 */
718 if (!sk_stream_memory_free(sk))
719 goto wait_for_sndbuf;
720
721 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
722 0, sk->sk_allocation);
723 if (!skb)
724 goto wait_for_memory;
725
726 /*
727 * Check whether we can use HW checksum.
728 */
729 if (sk->sk_route_caps &
730 (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
731 NETIF_F_HW_CSUM))
732 skb->ip_summed = CHECKSUM_HW;
733
734 skb_entail(sk, tp, skb);
735 copy = size_goal;
736 }
737
738 /* Try to append data to the end of skb. */
739 if (copy > seglen)
740 copy = seglen;
741
742 /* Where to copy to? */
743 if (skb_tailroom(skb) > 0) {
744 /* We have some space in skb head. Superb! */
745 if (copy > skb_tailroom(skb))
746 copy = skb_tailroom(skb);
747 if ((err = skb_add_data(skb, from, copy)) != 0)
748 goto do_fault;
749 } else {
750 int merge = 0;
751 int i = skb_shinfo(skb)->nr_frags;
752 struct page *page = TCP_PAGE(sk);
753 int off = TCP_OFF(sk);
754
755 if (skb_can_coalesce(skb, i, page, off) &&
756 off != PAGE_SIZE) {
757 /* We can extend the last page
758 * fragment. */
759 merge = 1;
760 } else if (i == MAX_SKB_FRAGS ||
761 (!i &&
762 !(sk->sk_route_caps & NETIF_F_SG))) {
763 /* Need to add new fragment and cannot
764 * do this because interface is non-SG,
765 * or because all the page slots are
766 * busy. */
767 tcp_mark_push(tp, skb);
768 goto new_segment;
769 } else if (page) {
770 if (off == PAGE_SIZE) {
771 put_page(page);
772 TCP_PAGE(sk) = page = NULL;
773 off = 0;
774 }
775 } else
776 off = 0;
777
778 if (copy > PAGE_SIZE - off)
779 copy = PAGE_SIZE - off;
780
781 if (!sk_stream_wmem_schedule(sk, copy))
782 goto wait_for_memory;
783
784 if (!page) {
785 /* Allocate new cache page. */
786 if (!(page = sk_stream_alloc_page(sk)))
787 goto wait_for_memory;
788 }
789
790 /* Time to copy data. We are close to
791 * the end! */
792 err = skb_copy_to_page(sk, from, skb, page,
793 off, copy);
794 if (err) {
795 /* If this page was new, give it to the
796 * socket so it does not get leaked.
797 */
798 if (!TCP_PAGE(sk)) {
799 TCP_PAGE(sk) = page;
800 TCP_OFF(sk) = 0;
801 }
802 goto do_error;
803 }
804
805 /* Update the skb. */
806 if (merge) {
807 skb_shinfo(skb)->frags[i - 1].size +=
808 copy;
809 } else {
810 skb_fill_page_desc(skb, i, page, off, copy);
811 if (TCP_PAGE(sk)) {
812 get_page(page);
813 } else if (off + copy < PAGE_SIZE) {
814 get_page(page);
815 TCP_PAGE(sk) = page;
816 }
817 }
818
819 TCP_OFF(sk) = off + copy;
820 }
821
822 if (!copied)
823 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
824
825 tp->write_seq += copy;
826 TCP_SKB_CB(skb)->end_seq += copy;
827 skb_shinfo(skb)->tso_segs = 0;
828
829 from += copy;
830 copied += copy;
831 if ((seglen -= copy) == 0 && iovlen == 0)
832 goto out;
833
834 if (skb->len < mss_now || (flags & MSG_OOB))
835 continue;
836
837 if (forced_push(tp)) {
838 tcp_mark_push(tp, skb);
839 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
840 } else if (skb == sk->sk_send_head)
841 tcp_push_one(sk, mss_now);
842 continue;
843
844 wait_for_sndbuf:
845 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
846 wait_for_memory:
847 if (copied)
848 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
849
850 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
851 goto do_error;
852
853 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
854 size_goal = tp->xmit_size_goal;
855 }
856 }
857
858 out:
859 if (copied)
860 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
861 TCP_CHECK_TIMER(sk);
862 release_sock(sk);
863 return copied;
864
865 do_fault:
866 if (!skb->len) {
867 if (sk->sk_send_head == skb)
868 sk->sk_send_head = NULL;
869 __skb_unlink(skb, &sk->sk_write_queue);
870 sk_stream_free_skb(sk, skb);
871 }
872
873 do_error:
874 if (copied)
875 goto out;
876 out_err:
877 err = sk_stream_error(sk, flags, err);
878 TCP_CHECK_TIMER(sk);
879 release_sock(sk);
880 return err;
881 }
882
883 /*
884 * Handle reading urgent data. BSD has very simple semantics for
885 * this, no blocking and very strange errors 8)
886 */
887
888 static int tcp_recv_urg(struct sock *sk, long timeo,
889 struct msghdr *msg, int len, int flags,
890 int *addr_len)
891 {
892 struct tcp_sock *tp = tcp_sk(sk);
893
894 /* No URG data to read. */
895 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
896 tp->urg_data == TCP_URG_READ)
897 return -EINVAL; /* Yes this is right ! */
898
899 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
900 return -ENOTCONN;
901
902 if (tp->urg_data & TCP_URG_VALID) {
903 int err = 0;
904 char c = tp->urg_data;
905
906 if (!(flags & MSG_PEEK))
907 tp->urg_data = TCP_URG_READ;
908
909 /* Read urgent data. */
910 msg->msg_flags |= MSG_OOB;
911
912 if (len > 0) {
913 if (!(flags & MSG_TRUNC))
914 err = memcpy_toiovec(msg->msg_iov, &c, 1);
915 len = 1;
916 } else
917 msg->msg_flags |= MSG_TRUNC;
918
919 return err ? -EFAULT : len;
920 }
921
922 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
923 return 0;
924
925 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
926 * the available implementations agree in this case:
927 * this call should never block, independent of the
928 * blocking state of the socket.
929 * Mike <pall@rz.uni-karlsruhe.de>
930 */
931 return -EAGAIN;
932 }
933
934 /* Clean up the receive buffer for full frames taken by the user,
935 * then send an ACK if necessary. COPIED is the number of bytes
936 * tcp_recvmsg has given to the user so far, it speeds up the
937 * calculation of whether or not we must ACK for the sake of
938 * a window update.
939 */
940 void tcp_cleanup_rbuf(struct sock *sk, int copied)
941 {
942 struct tcp_sock *tp = tcp_sk(sk);
943 int time_to_ack = 0;
944
945 #if TCP_DEBUG
946 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
947
948 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
949 #endif
950
951 if (inet_csk_ack_scheduled(sk)) {
952 const struct inet_connection_sock *icsk = inet_csk(sk);
953 /* Delayed ACKs frequently hit locked sockets during bulk
954 * receive. */
955 if (icsk->icsk_ack.blocked ||
956 /* Once-per-two-segments ACK was not sent by tcp_input.c */
957 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
958 /*
959 * If this read emptied read buffer, we send ACK, if
960 * connection is not bidirectional, user drained
961 * receive buffer and there was a small segment
962 * in queue.
963 */
964 (copied > 0 && (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
965 !icsk->icsk_ack.pingpong && !atomic_read(&sk->sk_rmem_alloc)))
966 time_to_ack = 1;
967 }
968
969 /* We send an ACK if we can now advertise a non-zero window
970 * which has been raised "significantly".
971 *
972 * Even if window raised up to infinity, do not send window open ACK
973 * in states, where we will not receive more. It is useless.
974 */
975 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
976 __u32 rcv_window_now = tcp_receive_window(tp);
977
978 /* Optimize, __tcp_select_window() is not cheap. */
979 if (2*rcv_window_now <= tp->window_clamp) {
980 __u32 new_window = __tcp_select_window(sk);
981
982 /* Send ACK now, if this read freed lots of space
983 * in our buffer. Certainly, new_window is new window.
984 * We can advertise it now, if it is not less than current one.
985 * "Lots" means "at least twice" here.
986 */
987 if (new_window && new_window >= 2 * rcv_window_now)
988 time_to_ack = 1;
989 }
990 }
991 if (time_to_ack)
992 tcp_send_ack(sk);
993 }
994
995 static void tcp_prequeue_process(struct sock *sk)
996 {
997 struct sk_buff *skb;
998 struct tcp_sock *tp = tcp_sk(sk);
999
1000 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1001
1002 /* RX process wants to run with disabled BHs, though it is not
1003 * necessary */
1004 local_bh_disable();
1005 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1006 sk->sk_backlog_rcv(sk, skb);
1007 local_bh_enable();
1008
1009 /* Clear memory counter. */
1010 tp->ucopy.memory = 0;
1011 }
1012
1013 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1014 {
1015 struct sk_buff *skb;
1016 u32 offset;
1017
1018 skb_queue_walk(&sk->sk_receive_queue, skb) {
1019 offset = seq - TCP_SKB_CB(skb)->seq;
1020 if (skb->h.th->syn)
1021 offset--;
1022 if (offset < skb->len || skb->h.th->fin) {
1023 *off = offset;
1024 return skb;
1025 }
1026 }
1027 return NULL;
1028 }
1029
1030 /*
1031 * This routine provides an alternative to tcp_recvmsg() for routines
1032 * that would like to handle copying from skbuffs directly in 'sendfile'
1033 * fashion.
1034 * Note:
1035 * - It is assumed that the socket was locked by the caller.
1036 * - The routine does not block.
1037 * - At present, there is no support for reading OOB data
1038 * or for 'peeking' the socket using this routine
1039 * (although both would be easy to implement).
1040 */
1041 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1042 sk_read_actor_t recv_actor)
1043 {
1044 struct sk_buff *skb;
1045 struct tcp_sock *tp = tcp_sk(sk);
1046 u32 seq = tp->copied_seq;
1047 u32 offset;
1048 int copied = 0;
1049
1050 if (sk->sk_state == TCP_LISTEN)
1051 return -ENOTCONN;
1052 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1053 if (offset < skb->len) {
1054 size_t used, len;
1055
1056 len = skb->len - offset;
1057 /* Stop reading if we hit a patch of urgent data */
1058 if (tp->urg_data) {
1059 u32 urg_offset = tp->urg_seq - seq;
1060 if (urg_offset < len)
1061 len = urg_offset;
1062 if (!len)
1063 break;
1064 }
1065 used = recv_actor(desc, skb, offset, len);
1066 if (used <= len) {
1067 seq += used;
1068 copied += used;
1069 offset += used;
1070 }
1071 if (offset != skb->len)
1072 break;
1073 }
1074 if (skb->h.th->fin) {
1075 sk_eat_skb(sk, skb, 0);
1076 ++seq;
1077 break;
1078 }
1079 sk_eat_skb(sk, skb, 0);
1080 if (!desc->count)
1081 break;
1082 }
1083 tp->copied_seq = seq;
1084
1085 tcp_rcv_space_adjust(sk);
1086
1087 /* Clean up data we have read: This will do ACK frames. */
1088 if (copied)
1089 tcp_cleanup_rbuf(sk, copied);
1090 return copied;
1091 }
1092
1093 /*
1094 * This routine copies from a sock struct into the user buffer.
1095 *
1096 * Technical note: in 2.3 we work on _locked_ socket, so that
1097 * tricks with *seq access order and skb->users are not required.
1098 * Probably, code can be easily improved even more.
1099 */
1100
1101 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1102 size_t len, int nonblock, int flags, int *addr_len)
1103 {
1104 struct tcp_sock *tp = tcp_sk(sk);
1105 int copied = 0;
1106 u32 peek_seq;
1107 u32 *seq;
1108 unsigned long used;
1109 int err;
1110 int target; /* Read at least this many bytes */
1111 long timeo;
1112 struct task_struct *user_recv = NULL;
1113 int copied_early = 0;
1114
1115 lock_sock(sk);
1116
1117 TCP_CHECK_TIMER(sk);
1118
1119 err = -ENOTCONN;
1120 if (sk->sk_state == TCP_LISTEN)
1121 goto out;
1122
1123 timeo = sock_rcvtimeo(sk, nonblock);
1124
1125 /* Urgent data needs to be handled specially. */
1126 if (flags & MSG_OOB)
1127 goto recv_urg;
1128
1129 seq = &tp->copied_seq;
1130 if (flags & MSG_PEEK) {
1131 peek_seq = tp->copied_seq;
1132 seq = &peek_seq;
1133 }
1134
1135 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1136
1137 #ifdef CONFIG_NET_DMA
1138 tp->ucopy.dma_chan = NULL;
1139 preempt_disable();
1140 if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1141 !sysctl_tcp_low_latency && __get_cpu_var(softnet_data.net_dma)) {
1142 preempt_enable_no_resched();
1143 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1144 } else
1145 preempt_enable_no_resched();
1146 #endif
1147
1148 do {
1149 struct sk_buff *skb;
1150 u32 offset;
1151
1152 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1153 if (tp->urg_data && tp->urg_seq == *seq) {
1154 if (copied)
1155 break;
1156 if (signal_pending(current)) {
1157 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1158 break;
1159 }
1160 }
1161
1162 /* Next get a buffer. */
1163
1164 skb = skb_peek(&sk->sk_receive_queue);
1165 do {
1166 if (!skb)
1167 break;
1168
1169 /* Now that we have two receive queues this
1170 * shouldn't happen.
1171 */
1172 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1173 printk(KERN_INFO "recvmsg bug: copied %X "
1174 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1175 break;
1176 }
1177 offset = *seq - TCP_SKB_CB(skb)->seq;
1178 if (skb->h.th->syn)
1179 offset--;
1180 if (offset < skb->len)
1181 goto found_ok_skb;
1182 if (skb->h.th->fin)
1183 goto found_fin_ok;
1184 BUG_TRAP(flags & MSG_PEEK);
1185 skb = skb->next;
1186 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1187
1188 /* Well, if we have backlog, try to process it now yet. */
1189
1190 if (copied >= target && !sk->sk_backlog.tail)
1191 break;
1192
1193 if (copied) {
1194 if (sk->sk_err ||
1195 sk->sk_state == TCP_CLOSE ||
1196 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1197 !timeo ||
1198 signal_pending(current) ||
1199 (flags & MSG_PEEK))
1200 break;
1201 } else {
1202 if (sock_flag(sk, SOCK_DONE))
1203 break;
1204
1205 if (sk->sk_err) {
1206 copied = sock_error(sk);
1207 break;
1208 }
1209
1210 if (sk->sk_shutdown & RCV_SHUTDOWN)
1211 break;
1212
1213 if (sk->sk_state == TCP_CLOSE) {
1214 if (!sock_flag(sk, SOCK_DONE)) {
1215 /* This occurs when user tries to read
1216 * from never connected socket.
1217 */
1218 copied = -ENOTCONN;
1219 break;
1220 }
1221 break;
1222 }
1223
1224 if (!timeo) {
1225 copied = -EAGAIN;
1226 break;
1227 }
1228
1229 if (signal_pending(current)) {
1230 copied = sock_intr_errno(timeo);
1231 break;
1232 }
1233 }
1234
1235 tcp_cleanup_rbuf(sk, copied);
1236
1237 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1238 /* Install new reader */
1239 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1240 user_recv = current;
1241 tp->ucopy.task = user_recv;
1242 tp->ucopy.iov = msg->msg_iov;
1243 }
1244
1245 tp->ucopy.len = len;
1246
1247 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1248 (flags & (MSG_PEEK | MSG_TRUNC)));
1249
1250 /* Ugly... If prequeue is not empty, we have to
1251 * process it before releasing socket, otherwise
1252 * order will be broken at second iteration.
1253 * More elegant solution is required!!!
1254 *
1255 * Look: we have the following (pseudo)queues:
1256 *
1257 * 1. packets in flight
1258 * 2. backlog
1259 * 3. prequeue
1260 * 4. receive_queue
1261 *
1262 * Each queue can be processed only if the next ones
1263 * are empty. At this point we have empty receive_queue.
1264 * But prequeue _can_ be not empty after 2nd iteration,
1265 * when we jumped to start of loop because backlog
1266 * processing added something to receive_queue.
1267 * We cannot release_sock(), because backlog contains
1268 * packets arrived _after_ prequeued ones.
1269 *
1270 * Shortly, algorithm is clear --- to process all
1271 * the queues in order. We could make it more directly,
1272 * requeueing packets from backlog to prequeue, if
1273 * is not empty. It is more elegant, but eats cycles,
1274 * unfortunately.
1275 */
1276 if (!skb_queue_empty(&tp->ucopy.prequeue))
1277 goto do_prequeue;
1278
1279 /* __ Set realtime policy in scheduler __ */
1280 }
1281
1282 if (copied >= target) {
1283 /* Do not sleep, just process backlog. */
1284 release_sock(sk);
1285 lock_sock(sk);
1286 } else
1287 sk_wait_data(sk, &timeo);
1288
1289 #ifdef CONFIG_NET_DMA
1290 tp->ucopy.wakeup = 0;
1291 #endif
1292
1293 if (user_recv) {
1294 int chunk;
1295
1296 /* __ Restore normal policy in scheduler __ */
1297
1298 if ((chunk = len - tp->ucopy.len) != 0) {
1299 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1300 len -= chunk;
1301 copied += chunk;
1302 }
1303
1304 if (tp->rcv_nxt == tp->copied_seq &&
1305 !skb_queue_empty(&tp->ucopy.prequeue)) {
1306 do_prequeue:
1307 tcp_prequeue_process(sk);
1308
1309 if ((chunk = len - tp->ucopy.len) != 0) {
1310 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1311 len -= chunk;
1312 copied += chunk;
1313 }
1314 }
1315 }
1316 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1317 if (net_ratelimit())
1318 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1319 current->comm, current->pid);
1320 peek_seq = tp->copied_seq;
1321 }
1322 continue;
1323
1324 found_ok_skb:
1325 /* Ok so how much can we use? */
1326 used = skb->len - offset;
1327 if (len < used)
1328 used = len;
1329
1330 /* Do we have urgent data here? */
1331 if (tp->urg_data) {
1332 u32 urg_offset = tp->urg_seq - *seq;
1333 if (urg_offset < used) {
1334 if (!urg_offset) {
1335 if (!sock_flag(sk, SOCK_URGINLINE)) {
1336 ++*seq;
1337 offset++;
1338 used--;
1339 if (!used)
1340 goto skip_copy;
1341 }
1342 } else
1343 used = urg_offset;
1344 }
1345 }
1346
1347 if (!(flags & MSG_TRUNC)) {
1348 #ifdef CONFIG_NET_DMA
1349 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1350 tp->ucopy.dma_chan = get_softnet_dma();
1351
1352 if (tp->ucopy.dma_chan) {
1353 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1354 tp->ucopy.dma_chan, skb, offset,
1355 msg->msg_iov, used,
1356 tp->ucopy.pinned_list);
1357
1358 if (tp->ucopy.dma_cookie < 0) {
1359
1360 printk(KERN_ALERT "dma_cookie < 0\n");
1361
1362 /* Exception. Bailout! */
1363 if (!copied)
1364 copied = -EFAULT;
1365 break;
1366 }
1367 if ((offset + used) == skb->len)
1368 copied_early = 1;
1369
1370 } else
1371 #endif
1372 {
1373 err = skb_copy_datagram_iovec(skb, offset,
1374 msg->msg_iov, used);
1375 if (err) {
1376 /* Exception. Bailout! */
1377 if (!copied)
1378 copied = -EFAULT;
1379 break;
1380 }
1381 }
1382 }
1383
1384 *seq += used;
1385 copied += used;
1386 len -= used;
1387
1388 tcp_rcv_space_adjust(sk);
1389
1390 skip_copy:
1391 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1392 tp->urg_data = 0;
1393 tcp_fast_path_check(sk, tp);
1394 }
1395 if (used + offset < skb->len)
1396 continue;
1397
1398 if (skb->h.th->fin)
1399 goto found_fin_ok;
1400 if (!(flags & MSG_PEEK)) {
1401 sk_eat_skb(sk, skb, copied_early);
1402 copied_early = 0;
1403 }
1404 continue;
1405
1406 found_fin_ok:
1407 /* Process the FIN. */
1408 ++*seq;
1409 if (!(flags & MSG_PEEK)) {
1410 sk_eat_skb(sk, skb, copied_early);
1411 copied_early = 0;
1412 }
1413 break;
1414 } while (len > 0);
1415
1416 if (user_recv) {
1417 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1418 int chunk;
1419
1420 tp->ucopy.len = copied > 0 ? len : 0;
1421
1422 tcp_prequeue_process(sk);
1423
1424 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1425 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1426 len -= chunk;
1427 copied += chunk;
1428 }
1429 }
1430
1431 tp->ucopy.task = NULL;
1432 tp->ucopy.len = 0;
1433 }
1434
1435 #ifdef CONFIG_NET_DMA
1436 if (tp->ucopy.dma_chan) {
1437 struct sk_buff *skb;
1438 dma_cookie_t done, used;
1439
1440 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1441
1442 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1443 tp->ucopy.dma_cookie, &done,
1444 &used) == DMA_IN_PROGRESS) {
1445 /* do partial cleanup of sk_async_wait_queue */
1446 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1447 (dma_async_is_complete(skb->dma_cookie, done,
1448 used) == DMA_SUCCESS)) {
1449 __skb_dequeue(&sk->sk_async_wait_queue);
1450 kfree_skb(skb);
1451 }
1452 }
1453
1454 /* Safe to free early-copied skbs now */
1455 __skb_queue_purge(&sk->sk_async_wait_queue);
1456 dma_chan_put(tp->ucopy.dma_chan);
1457 tp->ucopy.dma_chan = NULL;
1458 }
1459 if (tp->ucopy.pinned_list) {
1460 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1461 tp->ucopy.pinned_list = NULL;
1462 }
1463 #endif
1464
1465 /* According to UNIX98, msg_name/msg_namelen are ignored
1466 * on connected socket. I was just happy when found this 8) --ANK
1467 */
1468
1469 /* Clean up data we have read: This will do ACK frames. */
1470 tcp_cleanup_rbuf(sk, copied);
1471
1472 TCP_CHECK_TIMER(sk);
1473 release_sock(sk);
1474 return copied;
1475
1476 out:
1477 TCP_CHECK_TIMER(sk);
1478 release_sock(sk);
1479 return err;
1480
1481 recv_urg:
1482 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1483 goto out;
1484 }
1485
1486 /*
1487 * State processing on a close. This implements the state shift for
1488 * sending our FIN frame. Note that we only send a FIN for some
1489 * states. A shutdown() may have already sent the FIN, or we may be
1490 * closed.
1491 */
1492
1493 static const unsigned char new_state[16] = {
1494 /* current state: new state: action: */
1495 /* (Invalid) */ TCP_CLOSE,
1496 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1497 /* TCP_SYN_SENT */ TCP_CLOSE,
1498 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1499 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1500 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1501 /* TCP_TIME_WAIT */ TCP_CLOSE,
1502 /* TCP_CLOSE */ TCP_CLOSE,
1503 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1504 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1505 /* TCP_LISTEN */ TCP_CLOSE,
1506 /* TCP_CLOSING */ TCP_CLOSING,
1507 };
1508
1509 static int tcp_close_state(struct sock *sk)
1510 {
1511 int next = (int)new_state[sk->sk_state];
1512 int ns = next & TCP_STATE_MASK;
1513
1514 tcp_set_state(sk, ns);
1515
1516 return next & TCP_ACTION_FIN;
1517 }
1518
1519 /*
1520 * Shutdown the sending side of a connection. Much like close except
1521 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1522 */
1523
1524 void tcp_shutdown(struct sock *sk, int how)
1525 {
1526 /* We need to grab some memory, and put together a FIN,
1527 * and then put it into the queue to be sent.
1528 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1529 */
1530 if (!(how & SEND_SHUTDOWN))
1531 return;
1532
1533 /* If we've already sent a FIN, or it's a closed state, skip this. */
1534 if ((1 << sk->sk_state) &
1535 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1536 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1537 /* Clear out any half completed packets. FIN if needed. */
1538 if (tcp_close_state(sk))
1539 tcp_send_fin(sk);
1540 }
1541 }
1542
1543 void tcp_close(struct sock *sk, long timeout)
1544 {
1545 struct sk_buff *skb;
1546 int data_was_unread = 0;
1547 int state;
1548
1549 lock_sock(sk);
1550 sk->sk_shutdown = SHUTDOWN_MASK;
1551
1552 if (sk->sk_state == TCP_LISTEN) {
1553 tcp_set_state(sk, TCP_CLOSE);
1554
1555 /* Special case. */
1556 inet_csk_listen_stop(sk);
1557
1558 goto adjudge_to_death;
1559 }
1560
1561 /* We need to flush the recv. buffs. We do this only on the
1562 * descriptor close, not protocol-sourced closes, because the
1563 * reader process may not have drained the data yet!
1564 */
1565 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1566 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1567 skb->h.th->fin;
1568 data_was_unread += len;
1569 __kfree_skb(skb);
1570 }
1571
1572 sk_stream_mem_reclaim(sk);
1573
1574 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1575 * 3.10, we send a RST here because data was lost. To
1576 * witness the awful effects of the old behavior of always
1577 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1578 * a bulk GET in an FTP client, suspend the process, wait
1579 * for the client to advertise a zero window, then kill -9
1580 * the FTP client, wheee... Note: timeout is always zero
1581 * in such a case.
1582 */
1583 if (data_was_unread) {
1584 /* Unread data was tossed, zap the connection. */
1585 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1586 tcp_set_state(sk, TCP_CLOSE);
1587 tcp_send_active_reset(sk, GFP_KERNEL);
1588 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1589 /* Check zero linger _after_ checking for unread data. */
1590 sk->sk_prot->disconnect(sk, 0);
1591 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1592 } else if (tcp_close_state(sk)) {
1593 /* We FIN if the application ate all the data before
1594 * zapping the connection.
1595 */
1596
1597 /* RED-PEN. Formally speaking, we have broken TCP state
1598 * machine. State transitions:
1599 *
1600 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1601 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1602 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1603 *
1604 * are legal only when FIN has been sent (i.e. in window),
1605 * rather than queued out of window. Purists blame.
1606 *
1607 * F.e. "RFC state" is ESTABLISHED,
1608 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1609 *
1610 * The visible declinations are that sometimes
1611 * we enter time-wait state, when it is not required really
1612 * (harmless), do not send active resets, when they are
1613 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1614 * they look as CLOSING or LAST_ACK for Linux)
1615 * Probably, I missed some more holelets.
1616 * --ANK
1617 */
1618 tcp_send_fin(sk);
1619 }
1620
1621 sk_stream_wait_close(sk, timeout);
1622
1623 adjudge_to_death:
1624 state = sk->sk_state;
1625 sock_hold(sk);
1626 sock_orphan(sk);
1627 atomic_inc(sk->sk_prot->orphan_count);
1628
1629 /* It is the last release_sock in its life. It will remove backlog. */
1630 release_sock(sk);
1631
1632
1633 /* Now socket is owned by kernel and we acquire BH lock
1634 to finish close. No need to check for user refs.
1635 */
1636 local_bh_disable();
1637 bh_lock_sock(sk);
1638 BUG_TRAP(!sock_owned_by_user(sk));
1639
1640 /* Have we already been destroyed by a softirq or backlog? */
1641 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1642 goto out;
1643
1644 /* This is a (useful) BSD violating of the RFC. There is a
1645 * problem with TCP as specified in that the other end could
1646 * keep a socket open forever with no application left this end.
1647 * We use a 3 minute timeout (about the same as BSD) then kill
1648 * our end. If they send after that then tough - BUT: long enough
1649 * that we won't make the old 4*rto = almost no time - whoops
1650 * reset mistake.
1651 *
1652 * Nope, it was not mistake. It is really desired behaviour
1653 * f.e. on http servers, when such sockets are useless, but
1654 * consume significant resources. Let's do it with special
1655 * linger2 option. --ANK
1656 */
1657
1658 if (sk->sk_state == TCP_FIN_WAIT2) {
1659 struct tcp_sock *tp = tcp_sk(sk);
1660 if (tp->linger2 < 0) {
1661 tcp_set_state(sk, TCP_CLOSE);
1662 tcp_send_active_reset(sk, GFP_ATOMIC);
1663 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1664 } else {
1665 const int tmo = tcp_fin_time(sk);
1666
1667 if (tmo > TCP_TIMEWAIT_LEN) {
1668 inet_csk_reset_keepalive_timer(sk, tcp_fin_time(sk));
1669 } else {
1670 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1671 goto out;
1672 }
1673 }
1674 }
1675 if (sk->sk_state != TCP_CLOSE) {
1676 sk_stream_mem_reclaim(sk);
1677 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans ||
1678 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1679 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1680 if (net_ratelimit())
1681 printk(KERN_INFO "TCP: too many of orphaned "
1682 "sockets\n");
1683 tcp_set_state(sk, TCP_CLOSE);
1684 tcp_send_active_reset(sk, GFP_ATOMIC);
1685 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1686 }
1687 }
1688
1689 if (sk->sk_state == TCP_CLOSE)
1690 inet_csk_destroy_sock(sk);
1691 /* Otherwise, socket is reprieved until protocol close. */
1692
1693 out:
1694 bh_unlock_sock(sk);
1695 local_bh_enable();
1696 sock_put(sk);
1697 }
1698
1699 /* These states need RST on ABORT according to RFC793 */
1700
1701 static inline int tcp_need_reset(int state)
1702 {
1703 return (1 << state) &
1704 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1705 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1706 }
1707
1708 int tcp_disconnect(struct sock *sk, int flags)
1709 {
1710 struct inet_sock *inet = inet_sk(sk);
1711 struct inet_connection_sock *icsk = inet_csk(sk);
1712 struct tcp_sock *tp = tcp_sk(sk);
1713 int err = 0;
1714 int old_state = sk->sk_state;
1715
1716 if (old_state != TCP_CLOSE)
1717 tcp_set_state(sk, TCP_CLOSE);
1718
1719 /* ABORT function of RFC793 */
1720 if (old_state == TCP_LISTEN) {
1721 inet_csk_listen_stop(sk);
1722 } else if (tcp_need_reset(old_state) ||
1723 (tp->snd_nxt != tp->write_seq &&
1724 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1725 /* The last check adjusts for discrepancy of Linux wrt. RFC
1726 * states
1727 */
1728 tcp_send_active_reset(sk, gfp_any());
1729 sk->sk_err = ECONNRESET;
1730 } else if (old_state == TCP_SYN_SENT)
1731 sk->sk_err = ECONNRESET;
1732
1733 tcp_clear_xmit_timers(sk);
1734 __skb_queue_purge(&sk->sk_receive_queue);
1735 sk_stream_writequeue_purge(sk);
1736 __skb_queue_purge(&tp->out_of_order_queue);
1737 #ifdef CONFIG_NET_DMA
1738 __skb_queue_purge(&sk->sk_async_wait_queue);
1739 #endif
1740
1741 inet->dport = 0;
1742
1743 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1744 inet_reset_saddr(sk);
1745
1746 sk->sk_shutdown = 0;
1747 sock_reset_flag(sk, SOCK_DONE);
1748 tp->srtt = 0;
1749 if ((tp->write_seq += tp->max_window + 2) == 0)
1750 tp->write_seq = 1;
1751 icsk->icsk_backoff = 0;
1752 tp->snd_cwnd = 2;
1753 icsk->icsk_probes_out = 0;
1754 tp->packets_out = 0;
1755 tp->snd_ssthresh = 0x7fffffff;
1756 tp->snd_cwnd_cnt = 0;
1757 tp->bytes_acked = 0;
1758 tcp_set_ca_state(sk, TCP_CA_Open);
1759 tcp_clear_retrans(tp);
1760 inet_csk_delack_init(sk);
1761 sk->sk_send_head = NULL;
1762 tp->rx_opt.saw_tstamp = 0;
1763 tcp_sack_reset(&tp->rx_opt);
1764 __sk_dst_reset(sk);
1765
1766 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1767
1768 sk->sk_error_report(sk);
1769 return err;
1770 }
1771
1772 /*
1773 * Socket option code for TCP.
1774 */
1775 static int do_tcp_setsockopt(struct sock *sk, int level,
1776 int optname, char __user *optval, int optlen)
1777 {
1778 struct tcp_sock *tp = tcp_sk(sk);
1779 struct inet_connection_sock *icsk = inet_csk(sk);
1780 int val;
1781 int err = 0;
1782
1783 /* This is a string value all the others are int's */
1784 if (optname == TCP_CONGESTION) {
1785 char name[TCP_CA_NAME_MAX];
1786
1787 if (optlen < 1)
1788 return -EINVAL;
1789
1790 val = strncpy_from_user(name, optval,
1791 min(TCP_CA_NAME_MAX-1, optlen));
1792 if (val < 0)
1793 return -EFAULT;
1794 name[val] = 0;
1795
1796 lock_sock(sk);
1797 err = tcp_set_congestion_control(sk, name);
1798 release_sock(sk);
1799 return err;
1800 }
1801
1802 if (optlen < sizeof(int))
1803 return -EINVAL;
1804
1805 if (get_user(val, (int __user *)optval))
1806 return -EFAULT;
1807
1808 lock_sock(sk);
1809
1810 switch (optname) {
1811 case TCP_MAXSEG:
1812 /* Values greater than interface MTU won't take effect. However
1813 * at the point when this call is done we typically don't yet
1814 * know which interface is going to be used */
1815 if (val < 8 || val > MAX_TCP_WINDOW) {
1816 err = -EINVAL;
1817 break;
1818 }
1819 tp->rx_opt.user_mss = val;
1820 break;
1821
1822 case TCP_NODELAY:
1823 if (val) {
1824 /* TCP_NODELAY is weaker than TCP_CORK, so that
1825 * this option on corked socket is remembered, but
1826 * it is not activated until cork is cleared.
1827 *
1828 * However, when TCP_NODELAY is set we make
1829 * an explicit push, which overrides even TCP_CORK
1830 * for currently queued segments.
1831 */
1832 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1833 tcp_push_pending_frames(sk, tp);
1834 } else {
1835 tp->nonagle &= ~TCP_NAGLE_OFF;
1836 }
1837 break;
1838
1839 case TCP_CORK:
1840 /* When set indicates to always queue non-full frames.
1841 * Later the user clears this option and we transmit
1842 * any pending partial frames in the queue. This is
1843 * meant to be used alongside sendfile() to get properly
1844 * filled frames when the user (for example) must write
1845 * out headers with a write() call first and then use
1846 * sendfile to send out the data parts.
1847 *
1848 * TCP_CORK can be set together with TCP_NODELAY and it is
1849 * stronger than TCP_NODELAY.
1850 */
1851 if (val) {
1852 tp->nonagle |= TCP_NAGLE_CORK;
1853 } else {
1854 tp->nonagle &= ~TCP_NAGLE_CORK;
1855 if (tp->nonagle&TCP_NAGLE_OFF)
1856 tp->nonagle |= TCP_NAGLE_PUSH;
1857 tcp_push_pending_frames(sk, tp);
1858 }
1859 break;
1860
1861 case TCP_KEEPIDLE:
1862 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1863 err = -EINVAL;
1864 else {
1865 tp->keepalive_time = val * HZ;
1866 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1867 !((1 << sk->sk_state) &
1868 (TCPF_CLOSE | TCPF_LISTEN))) {
1869 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1870 if (tp->keepalive_time > elapsed)
1871 elapsed = tp->keepalive_time - elapsed;
1872 else
1873 elapsed = 0;
1874 inet_csk_reset_keepalive_timer(sk, elapsed);
1875 }
1876 }
1877 break;
1878 case TCP_KEEPINTVL:
1879 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1880 err = -EINVAL;
1881 else
1882 tp->keepalive_intvl = val * HZ;
1883 break;
1884 case TCP_KEEPCNT:
1885 if (val < 1 || val > MAX_TCP_KEEPCNT)
1886 err = -EINVAL;
1887 else
1888 tp->keepalive_probes = val;
1889 break;
1890 case TCP_SYNCNT:
1891 if (val < 1 || val > MAX_TCP_SYNCNT)
1892 err = -EINVAL;
1893 else
1894 icsk->icsk_syn_retries = val;
1895 break;
1896
1897 case TCP_LINGER2:
1898 if (val < 0)
1899 tp->linger2 = -1;
1900 else if (val > sysctl_tcp_fin_timeout / HZ)
1901 tp->linger2 = 0;
1902 else
1903 tp->linger2 = val * HZ;
1904 break;
1905
1906 case TCP_DEFER_ACCEPT:
1907 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1908 if (val > 0) {
1909 /* Translate value in seconds to number of
1910 * retransmits */
1911 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1912 val > ((TCP_TIMEOUT_INIT / HZ) <<
1913 icsk->icsk_accept_queue.rskq_defer_accept))
1914 icsk->icsk_accept_queue.rskq_defer_accept++;
1915 icsk->icsk_accept_queue.rskq_defer_accept++;
1916 }
1917 break;
1918
1919 case TCP_WINDOW_CLAMP:
1920 if (!val) {
1921 if (sk->sk_state != TCP_CLOSE) {
1922 err = -EINVAL;
1923 break;
1924 }
1925 tp->window_clamp = 0;
1926 } else
1927 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1928 SOCK_MIN_RCVBUF / 2 : val;
1929 break;
1930
1931 case TCP_QUICKACK:
1932 if (!val) {
1933 icsk->icsk_ack.pingpong = 1;
1934 } else {
1935 icsk->icsk_ack.pingpong = 0;
1936 if ((1 << sk->sk_state) &
1937 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1938 inet_csk_ack_scheduled(sk)) {
1939 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1940 tcp_cleanup_rbuf(sk, 1);
1941 if (!(val & 1))
1942 icsk->icsk_ack.pingpong = 1;
1943 }
1944 }
1945 break;
1946
1947 default:
1948 err = -ENOPROTOOPT;
1949 break;
1950 };
1951 release_sock(sk);
1952 return err;
1953 }
1954
1955 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1956 int optlen)
1957 {
1958 struct inet_connection_sock *icsk = inet_csk(sk);
1959
1960 if (level != SOL_TCP)
1961 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1962 optval, optlen);
1963 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1964 }
1965
1966 #ifdef CONFIG_COMPAT
1967 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1968 char __user *optval, int optlen)
1969 {
1970 if (level != SOL_TCP)
1971 return inet_csk_compat_setsockopt(sk, level, optname,
1972 optval, optlen);
1973 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1974 }
1975
1976 EXPORT_SYMBOL(compat_tcp_setsockopt);
1977 #endif
1978
1979 /* Return information about state of tcp endpoint in API format. */
1980 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1981 {
1982 struct tcp_sock *tp = tcp_sk(sk);
1983 const struct inet_connection_sock *icsk = inet_csk(sk);
1984 u32 now = tcp_time_stamp;
1985
1986 memset(info, 0, sizeof(*info));
1987
1988 info->tcpi_state = sk->sk_state;
1989 info->tcpi_ca_state = icsk->icsk_ca_state;
1990 info->tcpi_retransmits = icsk->icsk_retransmits;
1991 info->tcpi_probes = icsk->icsk_probes_out;
1992 info->tcpi_backoff = icsk->icsk_backoff;
1993
1994 if (tp->rx_opt.tstamp_ok)
1995 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1996 if (tp->rx_opt.sack_ok)
1997 info->tcpi_options |= TCPI_OPT_SACK;
1998 if (tp->rx_opt.wscale_ok) {
1999 info->tcpi_options |= TCPI_OPT_WSCALE;
2000 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2001 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2002 }
2003
2004 if (tp->ecn_flags&TCP_ECN_OK)
2005 info->tcpi_options |= TCPI_OPT_ECN;
2006
2007 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2008 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2009 info->tcpi_snd_mss = tp->mss_cache;
2010 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2011
2012 info->tcpi_unacked = tp->packets_out;
2013 info->tcpi_sacked = tp->sacked_out;
2014 info->tcpi_lost = tp->lost_out;
2015 info->tcpi_retrans = tp->retrans_out;
2016 info->tcpi_fackets = tp->fackets_out;
2017
2018 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2019 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2020 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2021
2022 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2023 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2024 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2025 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2026 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2027 info->tcpi_snd_cwnd = tp->snd_cwnd;
2028 info->tcpi_advmss = tp->advmss;
2029 info->tcpi_reordering = tp->reordering;
2030
2031 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2032 info->tcpi_rcv_space = tp->rcvq_space.space;
2033
2034 info->tcpi_total_retrans = tp->total_retrans;
2035 }
2036
2037 EXPORT_SYMBOL_GPL(tcp_get_info);
2038
2039 static int do_tcp_getsockopt(struct sock *sk, int level,
2040 int optname, char __user *optval, int __user *optlen)
2041 {
2042 struct inet_connection_sock *icsk = inet_csk(sk);
2043 struct tcp_sock *tp = tcp_sk(sk);
2044 int val, len;
2045
2046 if (get_user(len, optlen))
2047 return -EFAULT;
2048
2049 len = min_t(unsigned int, len, sizeof(int));
2050
2051 if (len < 0)
2052 return -EINVAL;
2053
2054 switch (optname) {
2055 case TCP_MAXSEG:
2056 val = tp->mss_cache;
2057 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2058 val = tp->rx_opt.user_mss;
2059 break;
2060 case TCP_NODELAY:
2061 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2062 break;
2063 case TCP_CORK:
2064 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2065 break;
2066 case TCP_KEEPIDLE:
2067 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2068 break;
2069 case TCP_KEEPINTVL:
2070 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2071 break;
2072 case TCP_KEEPCNT:
2073 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2074 break;
2075 case TCP_SYNCNT:
2076 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2077 break;
2078 case TCP_LINGER2:
2079 val = tp->linger2;
2080 if (val >= 0)
2081 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2082 break;
2083 case TCP_DEFER_ACCEPT:
2084 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2085 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2086 break;
2087 case TCP_WINDOW_CLAMP:
2088 val = tp->window_clamp;
2089 break;
2090 case TCP_INFO: {
2091 struct tcp_info info;
2092
2093 if (get_user(len, optlen))
2094 return -EFAULT;
2095
2096 tcp_get_info(sk, &info);
2097
2098 len = min_t(unsigned int, len, sizeof(info));
2099 if (put_user(len, optlen))
2100 return -EFAULT;
2101 if (copy_to_user(optval, &info, len))
2102 return -EFAULT;
2103 return 0;
2104 }
2105 case TCP_QUICKACK:
2106 val = !icsk->icsk_ack.pingpong;
2107 break;
2108
2109 case TCP_CONGESTION:
2110 if (get_user(len, optlen))
2111 return -EFAULT;
2112 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2113 if (put_user(len, optlen))
2114 return -EFAULT;
2115 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2116 return -EFAULT;
2117 return 0;
2118 default:
2119 return -ENOPROTOOPT;
2120 };
2121
2122 if (put_user(len, optlen))
2123 return -EFAULT;
2124 if (copy_to_user(optval, &val, len))
2125 return -EFAULT;
2126 return 0;
2127 }
2128
2129 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2130 int __user *optlen)
2131 {
2132 struct inet_connection_sock *icsk = inet_csk(sk);
2133
2134 if (level != SOL_TCP)
2135 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2136 optval, optlen);
2137 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2138 }
2139
2140 #ifdef CONFIG_COMPAT
2141 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2142 char __user *optval, int __user *optlen)
2143 {
2144 if (level != SOL_TCP)
2145 return inet_csk_compat_getsockopt(sk, level, optname,
2146 optval, optlen);
2147 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2148 }
2149
2150 EXPORT_SYMBOL(compat_tcp_getsockopt);
2151 #endif
2152
2153 extern void __skb_cb_too_small_for_tcp(int, int);
2154 extern struct tcp_congestion_ops tcp_reno;
2155
2156 static __initdata unsigned long thash_entries;
2157 static int __init set_thash_entries(char *str)
2158 {
2159 if (!str)
2160 return 0;
2161 thash_entries = simple_strtoul(str, &str, 0);
2162 return 1;
2163 }
2164 __setup("thash_entries=", set_thash_entries);
2165
2166 void __init tcp_init(void)
2167 {
2168 struct sk_buff *skb = NULL;
2169 unsigned long limit;
2170 int order, i, max_share;
2171
2172 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2173 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2174 sizeof(skb->cb));
2175
2176 tcp_hashinfo.bind_bucket_cachep =
2177 kmem_cache_create("tcp_bind_bucket",
2178 sizeof(struct inet_bind_bucket), 0,
2179 SLAB_HWCACHE_ALIGN, NULL, NULL);
2180 if (!tcp_hashinfo.bind_bucket_cachep)
2181 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2182
2183 /* Size and allocate the main established and bind bucket
2184 * hash tables.
2185 *
2186 * The methodology is similar to that of the buffer cache.
2187 */
2188 tcp_hashinfo.ehash =
2189 alloc_large_system_hash("TCP established",
2190 sizeof(struct inet_ehash_bucket),
2191 thash_entries,
2192 (num_physpages >= 128 * 1024) ?
2193 13 : 15,
2194 HASH_HIGHMEM,
2195 &tcp_hashinfo.ehash_size,
2196 NULL,
2197 0);
2198 tcp_hashinfo.ehash_size = (1 << tcp_hashinfo.ehash_size) >> 1;
2199 for (i = 0; i < (tcp_hashinfo.ehash_size << 1); i++) {
2200 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2201 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2202 }
2203
2204 tcp_hashinfo.bhash =
2205 alloc_large_system_hash("TCP bind",
2206 sizeof(struct inet_bind_hashbucket),
2207 tcp_hashinfo.ehash_size,
2208 (num_physpages >= 128 * 1024) ?
2209 13 : 15,
2210 HASH_HIGHMEM,
2211 &tcp_hashinfo.bhash_size,
2212 NULL,
2213 64 * 1024);
2214 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2215 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2216 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2217 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2218 }
2219
2220 /* Try to be a bit smarter and adjust defaults depending
2221 * on available memory.
2222 */
2223 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2224 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2225 order++)
2226 ;
2227 if (order >= 4) {
2228 sysctl_local_port_range[0] = 32768;
2229 sysctl_local_port_range[1] = 61000;
2230 tcp_death_row.sysctl_max_tw_buckets = 180000;
2231 sysctl_tcp_max_orphans = 4096 << (order - 4);
2232 sysctl_max_syn_backlog = 1024;
2233 } else if (order < 3) {
2234 sysctl_local_port_range[0] = 1024 * (3 - order);
2235 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2236 sysctl_tcp_max_orphans >>= (3 - order);
2237 sysctl_max_syn_backlog = 128;
2238 }
2239
2240 sysctl_tcp_mem[0] = 768 << order;
2241 sysctl_tcp_mem[1] = 1024 << order;
2242 sysctl_tcp_mem[2] = 1536 << order;
2243
2244 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2245 max_share = min(4UL*1024*1024, limit);
2246
2247 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2248 sysctl_tcp_wmem[1] = 16*1024;
2249 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2250
2251 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2252 sysctl_tcp_rmem[1] = 87380;
2253 sysctl_tcp_rmem[2] = max(87380, max_share);
2254
2255 printk(KERN_INFO "TCP: Hash tables configured "
2256 "(established %d bind %d)\n",
2257 tcp_hashinfo.ehash_size << 1, tcp_hashinfo.bhash_size);
2258
2259 tcp_register_congestion_control(&tcp_reno);
2260 }
2261
2262 EXPORT_SYMBOL(tcp_close);
2263 EXPORT_SYMBOL(tcp_disconnect);
2264 EXPORT_SYMBOL(tcp_getsockopt);
2265 EXPORT_SYMBOL(tcp_ioctl);
2266 EXPORT_SYMBOL(tcp_poll);
2267 EXPORT_SYMBOL(tcp_read_sock);
2268 EXPORT_SYMBOL(tcp_recvmsg);
2269 EXPORT_SYMBOL(tcp_sendmsg);
2270 EXPORT_SYMBOL(tcp_sendpage);
2271 EXPORT_SYMBOL(tcp_setsockopt);
2272 EXPORT_SYMBOL(tcp_shutdown);
2273 EXPORT_SYMBOL(tcp_statistics);
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