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drm: fix trivial coding errors
[linux/fpc-iii.git] / net / ipv4 / tcp.c
blob3fb1428e526eedb521057a49624fa28dde8b41cd
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 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Mark Evans, <evansmp@uhura.aston.ac.uk>
11 * Corey Minyard <wf-rch!minyard@relay.EU.net>
12 * Florian La Roche, <flla@stud.uni-sb.de>
13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14 * Linus Torvalds, <torvalds@cs.helsinki.fi>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
16 * Matthew Dillon, <dillon@apollo.west.oic.com>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Jorge Cwik, <jorge@laser.satlink.net>
19 *
20 * Fixes:
21 * Alan Cox : Numerous verify_area() calls
22 * Alan Cox : Set the ACK bit on a reset
23 * Alan Cox : Stopped it crashing if it closed while
24 * sk->inuse=1 and was trying to connect
25 * (tcp_err()).
26 * Alan Cox : All icmp error handling was broken
27 * pointers passed where wrong and the
28 * socket was looked up backwards. Nobody
29 * tested any icmp error code obviously.
30 * Alan Cox : tcp_err() now handled properly. It
31 * wakes people on errors. poll
32 * behaves and the icmp error race
33 * has gone by moving it into sock.c
34 * Alan Cox : tcp_send_reset() fixed to work for
35 * everything not just packets for
36 * unknown sockets.
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
39 * syn rule wrong]
40 * Herp Rosmanith : More reset fixes
41 * Alan Cox : No longer acks invalid rst frames.
42 * Acking any kind of RST is right out.
43 * Alan Cox : Sets an ignore me flag on an rst
44 * receive otherwise odd bits of prattle
45 * escape still
46 * Alan Cox : Fixed another acking RST frame bug.
47 * Should stop LAN workplace lockups.
48 * Alan Cox : Some tidyups using the new skb list
49 * facilities
50 * Alan Cox : sk->keepopen now seems to work
51 * Alan Cox : Pulls options out correctly on accepts
52 * Alan Cox : Fixed assorted sk->rqueue->next errors
53 * Alan Cox : PSH doesn't end a TCP read. Switched a
54 * bit to skb ops.
55 * Alan Cox : Tidied tcp_data to avoid a potential
56 * nasty.
57 * Alan Cox : Added some better commenting, as the
58 * tcp is hard to follow
59 * Alan Cox : Removed incorrect check for 20 * psh
60 * Michael O'Reilly : ack < copied bug fix.
61 * Johannes Stille : Misc tcp fixes (not all in yet).
62 * Alan Cox : FIN with no memory -> CRASH
63 * Alan Cox : Added socket option proto entries.
64 * Also added awareness of them to accept.
65 * Alan Cox : Added TCP options (SOL_TCP)
66 * Alan Cox : Switched wakeup calls to callbacks,
67 * so the kernel can layer network
68 * sockets.
69 * Alan Cox : Use ip_tos/ip_ttl settings.
70 * Alan Cox : Handle FIN (more) properly (we hope).
71 * Alan Cox : RST frames sent on unsynchronised
72 * state ack error.
73 * Alan Cox : Put in missing check for SYN bit.
74 * Alan Cox : Added tcp_select_window() aka NET2E
75 * window non shrink trick.
76 * Alan Cox : Added a couple of small NET2E timer
77 * fixes
78 * Charles Hedrick : TCP fixes
79 * Toomas Tamm : TCP window fixes
80 * Alan Cox : Small URG fix to rlogin ^C ack fight
81 * Charles Hedrick : Rewrote most of it to actually work
82 * Linus : Rewrote tcp_read() and URG handling
83 * completely
84 * Gerhard Koerting: Fixed some missing timer handling
85 * Matthew Dillon : Reworked TCP machine states as per RFC
86 * Gerhard Koerting: PC/TCP workarounds
87 * Adam Caldwell : Assorted timer/timing errors
88 * Matthew Dillon : Fixed another RST bug
89 * Alan Cox : Move to kernel side addressing changes.
90 * Alan Cox : Beginning work on TCP fastpathing
91 * (not yet usable)
92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
93 * Alan Cox : TCP fast path debugging
94 * Alan Cox : Window clamping
95 * Michael Riepe : Bug in tcp_check()
96 * Matt Dillon : More TCP improvements and RST bug fixes
97 * Matt Dillon : Yet more small nasties remove from the
98 * TCP code (Be very nice to this man if
99 * tcp finally works 100%) 8)
100 * Alan Cox : BSD accept semantics.
101 * Alan Cox : Reset on closedown bug.
102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
103 * Michael Pall : Handle poll() after URG properly in
104 * all cases.
105 * Michael Pall : Undo the last fix in tcp_read_urg()
106 * (multi URG PUSH broke rlogin).
107 * Michael Pall : Fix the multi URG PUSH problem in
108 * tcp_readable(), poll() after URG
109 * works now.
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
111 * BSD api.
112 * Alan Cox : Changed the semantics of sk->socket to
113 * fix a race and a signal problem with
114 * accept() and async I/O.
115 * Alan Cox : Relaxed the rules on tcp_sendto().
116 * Yury Shevchuk : Really fixed accept() blocking problem.
117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
118 * clients/servers which listen in on
119 * fixed ports.
120 * Alan Cox : Cleaned the above up and shrank it to
121 * a sensible code size.
122 * Alan Cox : Self connect lockup fix.
123 * Alan Cox : No connect to multicast.
124 * Ross Biro : Close unaccepted children on master
125 * socket close.
126 * Alan Cox : Reset tracing code.
127 * Alan Cox : Spurious resets on shutdown.
128 * Alan Cox : Giant 15 minute/60 second timer error
129 * Alan Cox : Small whoops in polling before an
130 * accept.
131 * Alan Cox : Kept the state trace facility since
132 * it's handy for debugging.
133 * Alan Cox : More reset handler fixes.
134 * Alan Cox : Started rewriting the code based on
135 * the RFC's for other useful protocol
136 * references see: Comer, KA9Q NOS, and
137 * for a reference on the difference
138 * between specifications and how BSD
139 * works see the 4.4lite source.
140 * A.N.Kuznetsov : Don't time wait on completion of tidy
141 * close.
142 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
143 * Linus Torvalds : Fixed BSD port reuse to work first syn
144 * Alan Cox : Reimplemented timers as per the RFC
145 * and using multiple timers for sanity.
146 * Alan Cox : Small bug fixes, and a lot of new
147 * comments.
148 * Alan Cox : Fixed dual reader crash by locking
149 * the buffers (much like datagram.c)
150 * Alan Cox : Fixed stuck sockets in probe. A probe
151 * now gets fed up of retrying without
152 * (even a no space) answer.
153 * Alan Cox : Extracted closing code better
154 * Alan Cox : Fixed the closing state machine to
155 * resemble the RFC.
156 * Alan Cox : More 'per spec' fixes.
157 * Jorge Cwik : Even faster checksumming.
158 * Alan Cox : tcp_data() doesn't ack illegal PSH
159 * only frames. At least one pc tcp stack
160 * generates them.
161 * Alan Cox : Cache last socket.
162 * Alan Cox : Per route irtt.
163 * Matt Day : poll()->select() match BSD precisely on error
164 * Alan Cox : New buffers
165 * Marc Tamsky : Various sk->prot->retransmits and
166 * sk->retransmits misupdating fixed.
167 * Fixed tcp_write_timeout: stuck close,
168 * and TCP syn retries gets used now.
169 * Mark Yarvis : In tcp_read_wakeup(), don't send an
170 * ack if state is TCP_CLOSED.
171 * Alan Cox : Look up device on a retransmit - routes may
172 * change. Doesn't yet cope with MSS shrink right
173 * but it's a start!
174 * Marc Tamsky : Closing in closing fixes.
175 * Mike Shaver : RFC1122 verifications.
176 * Alan Cox : rcv_saddr errors.
177 * Alan Cox : Block double connect().
178 * Alan Cox : Small hooks for enSKIP.
179 * Alexey Kuznetsov: Path MTU discovery.
180 * Alan Cox : Support soft errors.
181 * Alan Cox : Fix MTU discovery pathological case
182 * when the remote claims no mtu!
183 * Marc Tamsky : TCP_CLOSE fix.
184 * Colin (G3TNE) : Send a reset on syn ack replies in
185 * window but wrong (fixes NT lpd problems)
186 * Pedro Roque : Better TCP window handling, delayed ack.
187 * Joerg Reuter : No modification of locked buffers in
188 * tcp_do_retransmit()
189 * Eric Schenk : Changed receiver side silly window
190 * avoidance algorithm to BSD style
191 * algorithm. This doubles throughput
192 * against machines running Solaris,
193 * and seems to result in general
194 * improvement.
195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
196 * Willy Konynenberg : Transparent proxying support.
197 * Mike McLagan : Routing by source
198 * Keith Owens : Do proper merging with partial SKB's in
199 * tcp_do_sendmsg to avoid burstiness.
200 * Eric Schenk : Fix fast close down bug with
201 * shutdown() followed by close().
202 * Andi Kleen : Make poll agree with SIGIO
203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
204 * lingertime == 0 (RFC 793 ABORT Call)
205 * Hirokazu Takahashi : Use copy_from_user() instead of
206 * csum_and_copy_from_user() if possible.
207 *
208 * This program is free software; you can redistribute it and/or
209 * modify it under the terms of the GNU General Public License
210 * as published by the Free Software Foundation; either version
211 * 2 of the License, or(at your option) any later version.
212 *
213 * Description of States:
214 *
215 * TCP_SYN_SENT sent a connection request, waiting for ack
216 *
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
219 *
220 * TCP_ESTABLISHED connection established
221 *
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
224 *
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
226 * to shutdown
227 *
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
230 *
231 * TCP_TIME_WAIT timeout to catch resent junk before entering
232 * closed, can only be entered from FIN_WAIT2
233 * or CLOSING. Required because the other end
234 * may not have gotten our last ACK causing it
235 * to retransmit the data packet (which we ignore)
236 *
237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
238 * us to finish writing our data and to shutdown
239 * (we have to close() to move on to LAST_ACK)
240 *
241 * TCP_LAST_ACK out side has shutdown after remote has
242 * shutdown. There may still be data in our
243 * buffer that we have to finish sending
244 *
245 * TCP_CLOSE socket is finished
246 */
247
248 #include <linux/kernel.h>
249 #include <linux/module.h>
250 #include <linux/types.h>
251 #include <linux/fcntl.h>
252 #include <linux/poll.h>
253 #include <linux/init.h>
254 #include <linux/fs.h>
255 #include <linux/skbuff.h>
256 #include <linux/scatterlist.h>
257 #include <linux/splice.h>
258 #include <linux/net.h>
259 #include <linux/socket.h>
260 #include <linux/random.h>
261 #include <linux/bootmem.h>
262 #include <linux/highmem.h>
263 #include <linux/swap.h>
264 #include <linux/cache.h>
265 #include <linux/err.h>
266 #include <linux/crypto.h>
267 #include <linux/time.h>
268 #include <linux/slab.h>
269
270 #include <net/icmp.h>
271 #include <net/tcp.h>
272 #include <net/xfrm.h>
273 #include <net/ip.h>
274 #include <net/netdma.h>
275 #include <net/sock.h>
276
277 #include <asm/uaccess.h>
278 #include <asm/ioctls.h>
279
280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281
282 struct percpu_counter tcp_orphan_count;
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285 int sysctl_tcp_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
288
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
292
293 atomic_t tcp_memory_allocated; /* Current allocated memory. */
294 EXPORT_SYMBOL(tcp_memory_allocated);
295
296 /*
297 * Current number of TCP sockets.
298 */
299 struct percpu_counter tcp_sockets_allocated;
300 EXPORT_SYMBOL(tcp_sockets_allocated);
301
302 /*
303 * TCP splice context
304 */
305 struct tcp_splice_state {
306 struct pipe_inode_info *pipe;
307 size_t len;
308 unsigned int flags;
309 };
310
311 /*
312 * Pressure flag: try to collapse.
313 * Technical note: it is used by multiple contexts non atomically.
314 * All the __sk_mem_schedule() is of this nature: accounting
315 * is strict, actions are advisory and have some latency.
316 */
317 int tcp_memory_pressure __read_mostly;
318 EXPORT_SYMBOL(tcp_memory_pressure);
319
320 void tcp_enter_memory_pressure(struct sock *sk)
321 {
322 if (!tcp_memory_pressure) {
323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324 tcp_memory_pressure = 1;
325 }
326 }
327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329 /* Convert seconds to retransmits based on initial and max timeout */
330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331 {
332 u8 res = 0;
333
334 if (seconds > 0) {
335 int period = timeout;
336
337 res = 1;
338 while (seconds > period && res < 255) {
339 res++;
340 timeout <<= 1;
341 if (timeout > rto_max)
342 timeout = rto_max;
343 period += timeout;
344 }
345 }
346 return res;
347 }
348
349 /* Convert retransmits to seconds based on initial and max timeout */
350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351 {
352 int period = 0;
353
354 if (retrans > 0) {
355 period = timeout;
356 while (--retrans) {
357 timeout <<= 1;
358 if (timeout > rto_max)
359 timeout = rto_max;
360 period += timeout;
361 }
362 }
363 return period;
364 }
365
366 /*
367 * Wait for a TCP event.
368 *
369 * Note that we don't need to lock the socket, as the upper poll layers
370 * take care of normal races (between the test and the event) and we don't
371 * go look at any of the socket buffers directly.
372 */
373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374 {
375 unsigned int mask;
376 struct sock *sk = sock->sk;
377 struct tcp_sock *tp = tcp_sk(sk);
378
379 sock_poll_wait(file, sk_sleep(sk), wait);
380 if (sk->sk_state == TCP_LISTEN)
381 return inet_csk_listen_poll(sk);
382
383 /* Socket is not locked. We are protected from async events
384 * by poll logic and correct handling of state changes
385 * made by other threads is impossible in any case.
386 */
387
388 mask = 0;
389 if (sk->sk_err)
390 mask = POLLERR;
391
392 /*
393 * POLLHUP is certainly not done right. But poll() doesn't
394 * have a notion of HUP in just one direction, and for a
395 * socket the read side is more interesting.
396 *
397 * Some poll() documentation says that POLLHUP is incompatible
398 * with the POLLOUT/POLLWR flags, so somebody should check this
399 * all. But careful, it tends to be safer to return too many
400 * bits than too few, and you can easily break real applications
401 * if you don't tell them that something has hung up!
402 *
403 * Check-me.
404 *
405 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
406 * our fs/select.c). It means that after we received EOF,
407 * poll always returns immediately, making impossible poll() on write()
408 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
409 * if and only if shutdown has been made in both directions.
410 * Actually, it is interesting to look how Solaris and DUX
411 * solve this dilemma. I would prefer, if POLLHUP were maskable,
412 * then we could set it on SND_SHUTDOWN. BTW examples given
413 * in Stevens' books assume exactly this behaviour, it explains
414 * why POLLHUP is incompatible with POLLOUT. --ANK
415 *
416 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
417 * blocking on fresh not-connected or disconnected socket. --ANK
418 */
419 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
420 mask |= POLLHUP;
421 if (sk->sk_shutdown & RCV_SHUTDOWN)
422 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
423
424 /* Connected? */
425 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
426 int target = sock_rcvlowat(sk, 0, INT_MAX);
427
428 if (tp->urg_seq == tp->copied_seq &&
429 !sock_flag(sk, SOCK_URGINLINE) &&
430 tp->urg_data)
431 target++;
432
433 /* Potential race condition. If read of tp below will
434 * escape above sk->sk_state, we can be illegally awaken
435 * in SYN_* states. */
436 if (tp->rcv_nxt - tp->copied_seq >= target)
437 mask |= POLLIN | POLLRDNORM;
438
439 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
440 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
441 mask |= POLLOUT | POLLWRNORM;
442 } else { /* send SIGIO later */
443 set_bit(SOCK_ASYNC_NOSPACE,
444 &sk->sk_socket->flags);
445 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
446
447 /* Race breaker. If space is freed after
448 * wspace test but before the flags are set,
449 * IO signal will be lost.
450 */
451 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
452 mask |= POLLOUT | POLLWRNORM;
453 }
454 } else
455 mask |= POLLOUT | POLLWRNORM;
456
457 if (tp->urg_data & TCP_URG_VALID)
458 mask |= POLLPRI;
459 }
460 return mask;
461 }
462 EXPORT_SYMBOL(tcp_poll);
463
464 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
465 {
466 struct tcp_sock *tp = tcp_sk(sk);
467 int answ;
468
469 switch (cmd) {
470 case SIOCINQ:
471 if (sk->sk_state == TCP_LISTEN)
472 return -EINVAL;
473
474 lock_sock(sk);
475 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
476 answ = 0;
477 else if (sock_flag(sk, SOCK_URGINLINE) ||
478 !tp->urg_data ||
479 before(tp->urg_seq, tp->copied_seq) ||
480 !before(tp->urg_seq, tp->rcv_nxt)) {
481 struct sk_buff *skb;
482
483 answ = tp->rcv_nxt - tp->copied_seq;
484
485 /* Subtract 1, if FIN is in queue. */
486 skb = skb_peek_tail(&sk->sk_receive_queue);
487 if (answ && skb)
488 answ -= tcp_hdr(skb)->fin;
489 } else
490 answ = tp->urg_seq - tp->copied_seq;
491 release_sock(sk);
492 break;
493 case SIOCATMARK:
494 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
495 break;
496 case SIOCOUTQ:
497 if (sk->sk_state == TCP_LISTEN)
498 return -EINVAL;
499
500 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
501 answ = 0;
502 else
503 answ = tp->write_seq - tp->snd_una;
504 break;
505 default:
506 return -ENOIOCTLCMD;
507 }
508
509 return put_user(answ, (int __user *)arg);
510 }
511 EXPORT_SYMBOL(tcp_ioctl);
512
513 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
514 {
515 TCP_SKB_CB(skb)->flags |= TCPHDR_PSH;
516 tp->pushed_seq = tp->write_seq;
517 }
518
519 static inline int forced_push(struct tcp_sock *tp)
520 {
521 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
522 }
523
524 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
525 {
526 struct tcp_sock *tp = tcp_sk(sk);
527 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
528
529 skb->csum = 0;
530 tcb->seq = tcb->end_seq = tp->write_seq;
531 tcb->flags = TCPHDR_ACK;
532 tcb->sacked = 0;
533 skb_header_release(skb);
534 tcp_add_write_queue_tail(sk, skb);
535 sk->sk_wmem_queued += skb->truesize;
536 sk_mem_charge(sk, skb->truesize);
537 if (tp->nonagle & TCP_NAGLE_PUSH)
538 tp->nonagle &= ~TCP_NAGLE_PUSH;
539 }
540
541 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
542 {
543 if (flags & MSG_OOB)
544 tp->snd_up = tp->write_seq;
545 }
546
547 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
548 int nonagle)
549 {
550 if (tcp_send_head(sk)) {
551 struct tcp_sock *tp = tcp_sk(sk);
552
553 if (!(flags & MSG_MORE) || forced_push(tp))
554 tcp_mark_push(tp, tcp_write_queue_tail(sk));
555
556 tcp_mark_urg(tp, flags);
557 __tcp_push_pending_frames(sk, mss_now,
558 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
559 }
560 }
561
562 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
563 unsigned int offset, size_t len)
564 {
565 struct tcp_splice_state *tss = rd_desc->arg.data;
566 int ret;
567
568 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
569 tss->flags);
570 if (ret > 0)
571 rd_desc->count -= ret;
572 return ret;
573 }
574
575 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
576 {
577 /* Store TCP splice context information in read_descriptor_t. */
578 read_descriptor_t rd_desc = {
579 .arg.data = tss,
580 .count = tss->len,
581 };
582
583 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
584 }
585
586 /**
587 * tcp_splice_read - splice data from TCP socket to a pipe
588 * @sock: socket to splice from
589 * @ppos: position (not valid)
590 * @pipe: pipe to splice to
591 * @len: number of bytes to splice
592 * @flags: splice modifier flags
593 *
594 * Description:
595 * Will read pages from given socket and fill them into a pipe.
596 *
597 **/
598 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
599 struct pipe_inode_info *pipe, size_t len,
600 unsigned int flags)
601 {
602 struct sock *sk = sock->sk;
603 struct tcp_splice_state tss = {
604 .pipe = pipe,
605 .len = len,
606 .flags = flags,
607 };
608 long timeo;
609 ssize_t spliced;
610 int ret;
611
612 sock_rps_record_flow(sk);
613 /*
614 * We can't seek on a socket input
615 */
616 if (unlikely(*ppos))
617 return -ESPIPE;
618
619 ret = spliced = 0;
620
621 lock_sock(sk);
622
623 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
624 while (tss.len) {
625 ret = __tcp_splice_read(sk, &tss);
626 if (ret < 0)
627 break;
628 else if (!ret) {
629 if (spliced)
630 break;
631 if (sock_flag(sk, SOCK_DONE))
632 break;
633 if (sk->sk_err) {
634 ret = sock_error(sk);
635 break;
636 }
637 if (sk->sk_shutdown & RCV_SHUTDOWN)
638 break;
639 if (sk->sk_state == TCP_CLOSE) {
640 /*
641 * This occurs when user tries to read
642 * from never connected socket.
643 */
644 if (!sock_flag(sk, SOCK_DONE))
645 ret = -ENOTCONN;
646 break;
647 }
648 if (!timeo) {
649 ret = -EAGAIN;
650 break;
651 }
652 sk_wait_data(sk, &timeo);
653 if (signal_pending(current)) {
654 ret = sock_intr_errno(timeo);
655 break;
656 }
657 continue;
658 }
659 tss.len -= ret;
660 spliced += ret;
661
662 if (!timeo)
663 break;
664 release_sock(sk);
665 lock_sock(sk);
666
667 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
668 (sk->sk_shutdown & RCV_SHUTDOWN) ||
669 signal_pending(current))
670 break;
671 }
672
673 release_sock(sk);
674
675 if (spliced)
676 return spliced;
677
678 return ret;
679 }
680 EXPORT_SYMBOL(tcp_splice_read);
681
682 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
683 {
684 struct sk_buff *skb;
685
686 /* The TCP header must be at least 32-bit aligned. */
687 size = ALIGN(size, 4);
688
689 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
690 if (skb) {
691 if (sk_wmem_schedule(sk, skb->truesize)) {
692 /*
693 * Make sure that we have exactly size bytes
694 * available to the caller, no more, no less.
695 */
696 skb_reserve(skb, skb_tailroom(skb) - size);
697 return skb;
698 }
699 __kfree_skb(skb);
700 } else {
701 sk->sk_prot->enter_memory_pressure(sk);
702 sk_stream_moderate_sndbuf(sk);
703 }
704 return NULL;
705 }
706
707 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
708 int large_allowed)
709 {
710 struct tcp_sock *tp = tcp_sk(sk);
711 u32 xmit_size_goal, old_size_goal;
712
713 xmit_size_goal = mss_now;
714
715 if (large_allowed && sk_can_gso(sk)) {
716 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
717 inet_csk(sk)->icsk_af_ops->net_header_len -
718 inet_csk(sk)->icsk_ext_hdr_len -
719 tp->tcp_header_len);
720
721 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
722
723 /* We try hard to avoid divides here */
724 old_size_goal = tp->xmit_size_goal_segs * mss_now;
725
726 if (likely(old_size_goal <= xmit_size_goal &&
727 old_size_goal + mss_now > xmit_size_goal)) {
728 xmit_size_goal = old_size_goal;
729 } else {
730 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
731 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
732 }
733 }
734
735 return max(xmit_size_goal, mss_now);
736 }
737
738 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
739 {
740 int mss_now;
741
742 mss_now = tcp_current_mss(sk);
743 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
744
745 return mss_now;
746 }
747
748 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
749 size_t psize, int flags)
750 {
751 struct tcp_sock *tp = tcp_sk(sk);
752 int mss_now, size_goal;
753 int err;
754 ssize_t copied;
755 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
756
757 /* Wait for a connection to finish. */
758 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
759 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
760 goto out_err;
761
762 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
763
764 mss_now = tcp_send_mss(sk, &size_goal, flags);
765 copied = 0;
766
767 err = -EPIPE;
768 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
769 goto out_err;
770
771 while (psize > 0) {
772 struct sk_buff *skb = tcp_write_queue_tail(sk);
773 struct page *page = pages[poffset / PAGE_SIZE];
774 int copy, i, can_coalesce;
775 int offset = poffset % PAGE_SIZE;
776 int size = min_t(size_t, psize, PAGE_SIZE - offset);
777
778 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
779 new_segment:
780 if (!sk_stream_memory_free(sk))
781 goto wait_for_sndbuf;
782
783 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
784 if (!skb)
785 goto wait_for_memory;
786
787 skb_entail(sk, skb);
788 copy = size_goal;
789 }
790
791 if (copy > size)
792 copy = size;
793
794 i = skb_shinfo(skb)->nr_frags;
795 can_coalesce = skb_can_coalesce(skb, i, page, offset);
796 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
797 tcp_mark_push(tp, skb);
798 goto new_segment;
799 }
800 if (!sk_wmem_schedule(sk, copy))
801 goto wait_for_memory;
802
803 if (can_coalesce) {
804 skb_shinfo(skb)->frags[i - 1].size += copy;
805 } else {
806 get_page(page);
807 skb_fill_page_desc(skb, i, page, offset, copy);
808 }
809
810 skb->len += copy;
811 skb->data_len += copy;
812 skb->truesize += copy;
813 sk->sk_wmem_queued += copy;
814 sk_mem_charge(sk, copy);
815 skb->ip_summed = CHECKSUM_PARTIAL;
816 tp->write_seq += copy;
817 TCP_SKB_CB(skb)->end_seq += copy;
818 skb_shinfo(skb)->gso_segs = 0;
819
820 if (!copied)
821 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
822
823 copied += copy;
824 poffset += copy;
825 if (!(psize -= copy))
826 goto out;
827
828 if (skb->len < size_goal || (flags & MSG_OOB))
829 continue;
830
831 if (forced_push(tp)) {
832 tcp_mark_push(tp, skb);
833 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
834 } else if (skb == tcp_send_head(sk))
835 tcp_push_one(sk, mss_now);
836 continue;
837
838 wait_for_sndbuf:
839 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
840 wait_for_memory:
841 if (copied)
842 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
843
844 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
845 goto do_error;
846
847 mss_now = tcp_send_mss(sk, &size_goal, flags);
848 }
849
850 out:
851 if (copied)
852 tcp_push(sk, flags, mss_now, tp->nonagle);
853 return copied;
854
855 do_error:
856 if (copied)
857 goto out;
858 out_err:
859 return sk_stream_error(sk, flags, err);
860 }
861
862 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
863 size_t size, int flags)
864 {
865 ssize_t res;
866
867 if (!(sk->sk_route_caps & NETIF_F_SG) ||
868 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
869 return sock_no_sendpage(sk->sk_socket, page, offset, size,
870 flags);
871
872 lock_sock(sk);
873 TCP_CHECK_TIMER(sk);
874 res = do_tcp_sendpages(sk, &page, offset, size, flags);
875 TCP_CHECK_TIMER(sk);
876 release_sock(sk);
877 return res;
878 }
879 EXPORT_SYMBOL(tcp_sendpage);
880
881 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
882 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
883
884 static inline int select_size(struct sock *sk, int sg)
885 {
886 struct tcp_sock *tp = tcp_sk(sk);
887 int tmp = tp->mss_cache;
888
889 if (sg) {
890 if (sk_can_gso(sk))
891 tmp = 0;
892 else {
893 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
894
895 if (tmp >= pgbreak &&
896 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
897 tmp = pgbreak;
898 }
899 }
900
901 return tmp;
902 }
903
904 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
905 size_t size)
906 {
907 struct iovec *iov;
908 struct tcp_sock *tp = tcp_sk(sk);
909 struct sk_buff *skb;
910 int iovlen, flags;
911 int mss_now, size_goal;
912 int sg, err, copied;
913 long timeo;
914
915 lock_sock(sk);
916 TCP_CHECK_TIMER(sk);
917
918 flags = msg->msg_flags;
919 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
920
921 /* Wait for a connection to finish. */
922 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
923 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
924 goto out_err;
925
926 /* This should be in poll */
927 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
928
929 mss_now = tcp_send_mss(sk, &size_goal, flags);
930
931 /* Ok commence sending. */
932 iovlen = msg->msg_iovlen;
933 iov = msg->msg_iov;
934 copied = 0;
935
936 err = -EPIPE;
937 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
938 goto out_err;
939
940 sg = sk->sk_route_caps & NETIF_F_SG;
941
942 while (--iovlen >= 0) {
943 int seglen = iov->iov_len;
944 unsigned char __user *from = iov->iov_base;
945
946 iov++;
947
948 while (seglen > 0) {
949 int copy = 0;
950 int max = size_goal;
951
952 skb = tcp_write_queue_tail(sk);
953 if (tcp_send_head(sk)) {
954 if (skb->ip_summed == CHECKSUM_NONE)
955 max = mss_now;
956 copy = max - skb->len;
957 }
958
959 if (copy <= 0) {
960 new_segment:
961 /* Allocate new segment. If the interface is SG,
962 * allocate skb fitting to single page.
963 */
964 if (!sk_stream_memory_free(sk))
965 goto wait_for_sndbuf;
966
967 skb = sk_stream_alloc_skb(sk,
968 select_size(sk, sg),
969 sk->sk_allocation);
970 if (!skb)
971 goto wait_for_memory;
972
973 /*
974 * Check whether we can use HW checksum.
975 */
976 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
977 skb->ip_summed = CHECKSUM_PARTIAL;
978
979 skb_entail(sk, skb);
980 copy = size_goal;
981 max = size_goal;
982 }
983
984 /* Try to append data to the end of skb. */
985 if (copy > seglen)
986 copy = seglen;
987
988 /* Where to copy to? */
989 if (skb_tailroom(skb) > 0) {
990 /* We have some space in skb head. Superb! */
991 if (copy > skb_tailroom(skb))
992 copy = skb_tailroom(skb);
993 if ((err = skb_add_data(skb, from, copy)) != 0)
994 goto do_fault;
995 } else {
996 int merge = 0;
997 int i = skb_shinfo(skb)->nr_frags;
998 struct page *page = TCP_PAGE(sk);
999 int off = TCP_OFF(sk);
1000
1001 if (skb_can_coalesce(skb, i, page, off) &&
1002 off != PAGE_SIZE) {
1003 /* We can extend the last page
1004 * fragment. */
1005 merge = 1;
1006 } else if (i == MAX_SKB_FRAGS || !sg) {
1007 /* Need to add new fragment and cannot
1008 * do this because interface is non-SG,
1009 * or because all the page slots are
1010 * busy. */
1011 tcp_mark_push(tp, skb);
1012 goto new_segment;
1013 } else if (page) {
1014 if (off == PAGE_SIZE) {
1015 put_page(page);
1016 TCP_PAGE(sk) = page = NULL;
1017 off = 0;
1018 }
1019 } else
1020 off = 0;
1021
1022 if (copy > PAGE_SIZE - off)
1023 copy = PAGE_SIZE - off;
1024
1025 if (!sk_wmem_schedule(sk, copy))
1026 goto wait_for_memory;
1027
1028 if (!page) {
1029 /* Allocate new cache page. */
1030 if (!(page = sk_stream_alloc_page(sk)))
1031 goto wait_for_memory;
1032 }
1033
1034 /* Time to copy data. We are close to
1035 * the end! */
1036 err = skb_copy_to_page(sk, from, skb, page,
1037 off, copy);
1038 if (err) {
1039 /* If this page was new, give it to the
1040 * socket so it does not get leaked.
1041 */
1042 if (!TCP_PAGE(sk)) {
1043 TCP_PAGE(sk) = page;
1044 TCP_OFF(sk) = 0;
1045 }
1046 goto do_error;
1047 }
1048
1049 /* Update the skb. */
1050 if (merge) {
1051 skb_shinfo(skb)->frags[i - 1].size +=
1052 copy;
1053 } else {
1054 skb_fill_page_desc(skb, i, page, off, copy);
1055 if (TCP_PAGE(sk)) {
1056 get_page(page);
1057 } else if (off + copy < PAGE_SIZE) {
1058 get_page(page);
1059 TCP_PAGE(sk) = page;
1060 }
1061 }
1062
1063 TCP_OFF(sk) = off + copy;
1064 }
1065
1066 if (!copied)
1067 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
1068
1069 tp->write_seq += copy;
1070 TCP_SKB_CB(skb)->end_seq += copy;
1071 skb_shinfo(skb)->gso_segs = 0;
1072
1073 from += copy;
1074 copied += copy;
1075 if ((seglen -= copy) == 0 && iovlen == 0)
1076 goto out;
1077
1078 if (skb->len < max || (flags & MSG_OOB))
1079 continue;
1080
1081 if (forced_push(tp)) {
1082 tcp_mark_push(tp, skb);
1083 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1084 } else if (skb == tcp_send_head(sk))
1085 tcp_push_one(sk, mss_now);
1086 continue;
1087
1088 wait_for_sndbuf:
1089 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1090 wait_for_memory:
1091 if (copied)
1092 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1093
1094 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1095 goto do_error;
1096
1097 mss_now = tcp_send_mss(sk, &size_goal, flags);
1098 }
1099 }
1100
1101 out:
1102 if (copied)
1103 tcp_push(sk, flags, mss_now, tp->nonagle);
1104 TCP_CHECK_TIMER(sk);
1105 release_sock(sk);
1106 return copied;
1107
1108 do_fault:
1109 if (!skb->len) {
1110 tcp_unlink_write_queue(skb, sk);
1111 /* It is the one place in all of TCP, except connection
1112 * reset, where we can be unlinking the send_head.
1113 */
1114 tcp_check_send_head(sk, skb);
1115 sk_wmem_free_skb(sk, skb);
1116 }
1117
1118 do_error:
1119 if (copied)
1120 goto out;
1121 out_err:
1122 err = sk_stream_error(sk, flags, err);
1123 TCP_CHECK_TIMER(sk);
1124 release_sock(sk);
1125 return err;
1126 }
1127 EXPORT_SYMBOL(tcp_sendmsg);
1128
1129 /*
1130 * Handle reading urgent data. BSD has very simple semantics for
1131 * this, no blocking and very strange errors 8)
1132 */
1133
1134 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1135 {
1136 struct tcp_sock *tp = tcp_sk(sk);
1137
1138 /* No URG data to read. */
1139 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1140 tp->urg_data == TCP_URG_READ)
1141 return -EINVAL; /* Yes this is right ! */
1142
1143 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1144 return -ENOTCONN;
1145
1146 if (tp->urg_data & TCP_URG_VALID) {
1147 int err = 0;
1148 char c = tp->urg_data;
1149
1150 if (!(flags & MSG_PEEK))
1151 tp->urg_data = TCP_URG_READ;
1152
1153 /* Read urgent data. */
1154 msg->msg_flags |= MSG_OOB;
1155
1156 if (len > 0) {
1157 if (!(flags & MSG_TRUNC))
1158 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1159 len = 1;
1160 } else
1161 msg->msg_flags |= MSG_TRUNC;
1162
1163 return err ? -EFAULT : len;
1164 }
1165
1166 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1167 return 0;
1168
1169 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1170 * the available implementations agree in this case:
1171 * this call should never block, independent of the
1172 * blocking state of the socket.
1173 * Mike <pall@rz.uni-karlsruhe.de>
1174 */
1175 return -EAGAIN;
1176 }
1177
1178 /* Clean up the receive buffer for full frames taken by the user,
1179 * then send an ACK if necessary. COPIED is the number of bytes
1180 * tcp_recvmsg has given to the user so far, it speeds up the
1181 * calculation of whether or not we must ACK for the sake of
1182 * a window update.
1183 */
1184 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1185 {
1186 struct tcp_sock *tp = tcp_sk(sk);
1187 int time_to_ack = 0;
1188
1189 #if TCP_DEBUG
1190 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1191
1192 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1193 KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1194 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1195 #endif
1196
1197 if (inet_csk_ack_scheduled(sk)) {
1198 const struct inet_connection_sock *icsk = inet_csk(sk);
1199 /* Delayed ACKs frequently hit locked sockets during bulk
1200 * receive. */
1201 if (icsk->icsk_ack.blocked ||
1202 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1203 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1204 /*
1205 * If this read emptied read buffer, we send ACK, if
1206 * connection is not bidirectional, user drained
1207 * receive buffer and there was a small segment
1208 * in queue.
1209 */
1210 (copied > 0 &&
1211 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1212 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1213 !icsk->icsk_ack.pingpong)) &&
1214 !atomic_read(&sk->sk_rmem_alloc)))
1215 time_to_ack = 1;
1216 }
1217
1218 /* We send an ACK if we can now advertise a non-zero window
1219 * which has been raised "significantly".
1220 *
1221 * Even if window raised up to infinity, do not send window open ACK
1222 * in states, where we will not receive more. It is useless.
1223 */
1224 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1225 __u32 rcv_window_now = tcp_receive_window(tp);
1226
1227 /* Optimize, __tcp_select_window() is not cheap. */
1228 if (2*rcv_window_now <= tp->window_clamp) {
1229 __u32 new_window = __tcp_select_window(sk);
1230
1231 /* Send ACK now, if this read freed lots of space
1232 * in our buffer. Certainly, new_window is new window.
1233 * We can advertise it now, if it is not less than current one.
1234 * "Lots" means "at least twice" here.
1235 */
1236 if (new_window && new_window >= 2 * rcv_window_now)
1237 time_to_ack = 1;
1238 }
1239 }
1240 if (time_to_ack)
1241 tcp_send_ack(sk);
1242 }
1243
1244 static void tcp_prequeue_process(struct sock *sk)
1245 {
1246 struct sk_buff *skb;
1247 struct tcp_sock *tp = tcp_sk(sk);
1248
1249 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1250
1251 /* RX process wants to run with disabled BHs, though it is not
1252 * necessary */
1253 local_bh_disable();
1254 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1255 sk_backlog_rcv(sk, skb);
1256 local_bh_enable();
1257
1258 /* Clear memory counter. */
1259 tp->ucopy.memory = 0;
1260 }
1261
1262 #ifdef CONFIG_NET_DMA
1263 static void tcp_service_net_dma(struct sock *sk, bool wait)
1264 {
1265 dma_cookie_t done, used;
1266 dma_cookie_t last_issued;
1267 struct tcp_sock *tp = tcp_sk(sk);
1268
1269 if (!tp->ucopy.dma_chan)
1270 return;
1271
1272 last_issued = tp->ucopy.dma_cookie;
1273 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1274
1275 do {
1276 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1277 last_issued, &done,
1278 &used) == DMA_SUCCESS) {
1279 /* Safe to free early-copied skbs now */
1280 __skb_queue_purge(&sk->sk_async_wait_queue);
1281 break;
1282 } else {
1283 struct sk_buff *skb;
1284 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1285 (dma_async_is_complete(skb->dma_cookie, done,
1286 used) == DMA_SUCCESS)) {
1287 __skb_dequeue(&sk->sk_async_wait_queue);
1288 kfree_skb(skb);
1289 }
1290 }
1291 } while (wait);
1292 }
1293 #endif
1294
1295 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1296 {
1297 struct sk_buff *skb;
1298 u32 offset;
1299
1300 skb_queue_walk(&sk->sk_receive_queue, skb) {
1301 offset = seq - TCP_SKB_CB(skb)->seq;
1302 if (tcp_hdr(skb)->syn)
1303 offset--;
1304 if (offset < skb->len || tcp_hdr(skb)->fin) {
1305 *off = offset;
1306 return skb;
1307 }
1308 }
1309 return NULL;
1310 }
1311
1312 /*
1313 * This routine provides an alternative to tcp_recvmsg() for routines
1314 * that would like to handle copying from skbuffs directly in 'sendfile'
1315 * fashion.
1316 * Note:
1317 * - It is assumed that the socket was locked by the caller.
1318 * - The routine does not block.
1319 * - At present, there is no support for reading OOB data
1320 * or for 'peeking' the socket using this routine
1321 * (although both would be easy to implement).
1322 */
1323 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1324 sk_read_actor_t recv_actor)
1325 {
1326 struct sk_buff *skb;
1327 struct tcp_sock *tp = tcp_sk(sk);
1328 u32 seq = tp->copied_seq;
1329 u32 offset;
1330 int copied = 0;
1331
1332 if (sk->sk_state == TCP_LISTEN)
1333 return -ENOTCONN;
1334 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1335 if (offset < skb->len) {
1336 int used;
1337 size_t len;
1338
1339 len = skb->len - offset;
1340 /* Stop reading if we hit a patch of urgent data */
1341 if (tp->urg_data) {
1342 u32 urg_offset = tp->urg_seq - seq;
1343 if (urg_offset < len)
1344 len = urg_offset;
1345 if (!len)
1346 break;
1347 }
1348 used = recv_actor(desc, skb, offset, len);
1349 if (used < 0) {
1350 if (!copied)
1351 copied = used;
1352 break;
1353 } else if (used <= len) {
1354 seq += used;
1355 copied += used;
1356 offset += used;
1357 }
1358 /*
1359 * If recv_actor drops the lock (e.g. TCP splice
1360 * receive) the skb pointer might be invalid when
1361 * getting here: tcp_collapse might have deleted it
1362 * while aggregating skbs from the socket queue.
1363 */
1364 skb = tcp_recv_skb(sk, seq-1, &offset);
1365 if (!skb || (offset+1 != skb->len))
1366 break;
1367 }
1368 if (tcp_hdr(skb)->fin) {
1369 sk_eat_skb(sk, skb, 0);
1370 ++seq;
1371 break;
1372 }
1373 sk_eat_skb(sk, skb, 0);
1374 if (!desc->count)
1375 break;
1376 tp->copied_seq = seq;
1377 }
1378 tp->copied_seq = seq;
1379
1380 tcp_rcv_space_adjust(sk);
1381
1382 /* Clean up data we have read: This will do ACK frames. */
1383 if (copied > 0)
1384 tcp_cleanup_rbuf(sk, copied);
1385 return copied;
1386 }
1387 EXPORT_SYMBOL(tcp_read_sock);
1388
1389 /*
1390 * This routine copies from a sock struct into the user buffer.
1391 *
1392 * Technical note: in 2.3 we work on _locked_ socket, so that
1393 * tricks with *seq access order and skb->users are not required.
1394 * Probably, code can be easily improved even more.
1395 */
1396
1397 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1398 size_t len, int nonblock, int flags, int *addr_len)
1399 {
1400 struct tcp_sock *tp = tcp_sk(sk);
1401 int copied = 0;
1402 u32 peek_seq;
1403 u32 *seq;
1404 unsigned long used;
1405 int err;
1406 int target; /* Read at least this many bytes */
1407 long timeo;
1408 struct task_struct *user_recv = NULL;
1409 int copied_early = 0;
1410 struct sk_buff *skb;
1411 u32 urg_hole = 0;
1412
1413 lock_sock(sk);
1414
1415 TCP_CHECK_TIMER(sk);
1416
1417 err = -ENOTCONN;
1418 if (sk->sk_state == TCP_LISTEN)
1419 goto out;
1420
1421 timeo = sock_rcvtimeo(sk, nonblock);
1422
1423 /* Urgent data needs to be handled specially. */
1424 if (flags & MSG_OOB)
1425 goto recv_urg;
1426
1427 seq = &tp->copied_seq;
1428 if (flags & MSG_PEEK) {
1429 peek_seq = tp->copied_seq;
1430 seq = &peek_seq;
1431 }
1432
1433 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1434
1435 #ifdef CONFIG_NET_DMA
1436 tp->ucopy.dma_chan = NULL;
1437 preempt_disable();
1438 skb = skb_peek_tail(&sk->sk_receive_queue);
1439 {
1440 int available = 0;
1441
1442 if (skb)
1443 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1444 if ((available < target) &&
1445 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1446 !sysctl_tcp_low_latency &&
1447 dma_find_channel(DMA_MEMCPY)) {
1448 preempt_enable_no_resched();
1449 tp->ucopy.pinned_list =
1450 dma_pin_iovec_pages(msg->msg_iov, len);
1451 } else {
1452 preempt_enable_no_resched();
1453 }
1454 }
1455 #endif
1456
1457 do {
1458 u32 offset;
1459
1460 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1461 if (tp->urg_data && tp->urg_seq == *seq) {
1462 if (copied)
1463 break;
1464 if (signal_pending(current)) {
1465 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1466 break;
1467 }
1468 }
1469
1470 /* Next get a buffer. */
1471
1472 skb_queue_walk(&sk->sk_receive_queue, skb) {
1473 /* Now that we have two receive queues this
1474 * shouldn't happen.
1475 */
1476 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1477 KERN_INFO "recvmsg bug: copied %X "
1478 "seq %X rcvnxt %X fl %X\n", *seq,
1479 TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1480 flags))
1481 break;
1482
1483 offset = *seq - TCP_SKB_CB(skb)->seq;
1484 if (tcp_hdr(skb)->syn)
1485 offset--;
1486 if (offset < skb->len)
1487 goto found_ok_skb;
1488 if (tcp_hdr(skb)->fin)
1489 goto found_fin_ok;
1490 WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1491 "copied %X seq %X rcvnxt %X fl %X\n",
1492 *seq, TCP_SKB_CB(skb)->seq,
1493 tp->rcv_nxt, flags);
1494 }
1495
1496 /* Well, if we have backlog, try to process it now yet. */
1497
1498 if (copied >= target && !sk->sk_backlog.tail)
1499 break;
1500
1501 if (copied) {
1502 if (sk->sk_err ||
1503 sk->sk_state == TCP_CLOSE ||
1504 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1505 !timeo ||
1506 signal_pending(current))
1507 break;
1508 } else {
1509 if (sock_flag(sk, SOCK_DONE))
1510 break;
1511
1512 if (sk->sk_err) {
1513 copied = sock_error(sk);
1514 break;
1515 }
1516
1517 if (sk->sk_shutdown & RCV_SHUTDOWN)
1518 break;
1519
1520 if (sk->sk_state == TCP_CLOSE) {
1521 if (!sock_flag(sk, SOCK_DONE)) {
1522 /* This occurs when user tries to read
1523 * from never connected socket.
1524 */
1525 copied = -ENOTCONN;
1526 break;
1527 }
1528 break;
1529 }
1530
1531 if (!timeo) {
1532 copied = -EAGAIN;
1533 break;
1534 }
1535
1536 if (signal_pending(current)) {
1537 copied = sock_intr_errno(timeo);
1538 break;
1539 }
1540 }
1541
1542 tcp_cleanup_rbuf(sk, copied);
1543
1544 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1545 /* Install new reader */
1546 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1547 user_recv = current;
1548 tp->ucopy.task = user_recv;
1549 tp->ucopy.iov = msg->msg_iov;
1550 }
1551
1552 tp->ucopy.len = len;
1553
1554 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1555 !(flags & (MSG_PEEK | MSG_TRUNC)));
1556
1557 /* Ugly... If prequeue is not empty, we have to
1558 * process it before releasing socket, otherwise
1559 * order will be broken at second iteration.
1560 * More elegant solution is required!!!
1561 *
1562 * Look: we have the following (pseudo)queues:
1563 *
1564 * 1. packets in flight
1565 * 2. backlog
1566 * 3. prequeue
1567 * 4. receive_queue
1568 *
1569 * Each queue can be processed only if the next ones
1570 * are empty. At this point we have empty receive_queue.
1571 * But prequeue _can_ be not empty after 2nd iteration,
1572 * when we jumped to start of loop because backlog
1573 * processing added something to receive_queue.
1574 * We cannot release_sock(), because backlog contains
1575 * packets arrived _after_ prequeued ones.
1576 *
1577 * Shortly, algorithm is clear --- to process all
1578 * the queues in order. We could make it more directly,
1579 * requeueing packets from backlog to prequeue, if
1580 * is not empty. It is more elegant, but eats cycles,
1581 * unfortunately.
1582 */
1583 if (!skb_queue_empty(&tp->ucopy.prequeue))
1584 goto do_prequeue;
1585
1586 /* __ Set realtime policy in scheduler __ */
1587 }
1588
1589 #ifdef CONFIG_NET_DMA
1590 if (tp->ucopy.dma_chan)
1591 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1592 #endif
1593 if (copied >= target) {
1594 /* Do not sleep, just process backlog. */
1595 release_sock(sk);
1596 lock_sock(sk);
1597 } else
1598 sk_wait_data(sk, &timeo);
1599
1600 #ifdef CONFIG_NET_DMA
1601 tcp_service_net_dma(sk, false); /* Don't block */
1602 tp->ucopy.wakeup = 0;
1603 #endif
1604
1605 if (user_recv) {
1606 int chunk;
1607
1608 /* __ Restore normal policy in scheduler __ */
1609
1610 if ((chunk = len - tp->ucopy.len) != 0) {
1611 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1612 len -= chunk;
1613 copied += chunk;
1614 }
1615
1616 if (tp->rcv_nxt == tp->copied_seq &&
1617 !skb_queue_empty(&tp->ucopy.prequeue)) {
1618 do_prequeue:
1619 tcp_prequeue_process(sk);
1620
1621 if ((chunk = len - tp->ucopy.len) != 0) {
1622 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1623 len -= chunk;
1624 copied += chunk;
1625 }
1626 }
1627 }
1628 if ((flags & MSG_PEEK) &&
1629 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1630 if (net_ratelimit())
1631 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1632 current->comm, task_pid_nr(current));
1633 peek_seq = tp->copied_seq;
1634 }
1635 continue;
1636
1637 found_ok_skb:
1638 /* Ok so how much can we use? */
1639 used = skb->len - offset;
1640 if (len < used)
1641 used = len;
1642
1643 /* Do we have urgent data here? */
1644 if (tp->urg_data) {
1645 u32 urg_offset = tp->urg_seq - *seq;
1646 if (urg_offset < used) {
1647 if (!urg_offset) {
1648 if (!sock_flag(sk, SOCK_URGINLINE)) {
1649 ++*seq;
1650 urg_hole++;
1651 offset++;
1652 used--;
1653 if (!used)
1654 goto skip_copy;
1655 }
1656 } else
1657 used = urg_offset;
1658 }
1659 }
1660
1661 if (!(flags & MSG_TRUNC)) {
1662 #ifdef CONFIG_NET_DMA
1663 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1664 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1665
1666 if (tp->ucopy.dma_chan) {
1667 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1668 tp->ucopy.dma_chan, skb, offset,
1669 msg->msg_iov, used,
1670 tp->ucopy.pinned_list);
1671
1672 if (tp->ucopy.dma_cookie < 0) {
1673
1674 printk(KERN_ALERT "dma_cookie < 0\n");
1675
1676 /* Exception. Bailout! */
1677 if (!copied)
1678 copied = -EFAULT;
1679 break;
1680 }
1681
1682 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1683
1684 if ((offset + used) == skb->len)
1685 copied_early = 1;
1686
1687 } else
1688 #endif
1689 {
1690 err = skb_copy_datagram_iovec(skb, offset,
1691 msg->msg_iov, used);
1692 if (err) {
1693 /* Exception. Bailout! */
1694 if (!copied)
1695 copied = -EFAULT;
1696 break;
1697 }
1698 }
1699 }
1700
1701 *seq += used;
1702 copied += used;
1703 len -= used;
1704
1705 tcp_rcv_space_adjust(sk);
1706
1707 skip_copy:
1708 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1709 tp->urg_data = 0;
1710 tcp_fast_path_check(sk);
1711 }
1712 if (used + offset < skb->len)
1713 continue;
1714
1715 if (tcp_hdr(skb)->fin)
1716 goto found_fin_ok;
1717 if (!(flags & MSG_PEEK)) {
1718 sk_eat_skb(sk, skb, copied_early);
1719 copied_early = 0;
1720 }
1721 continue;
1722
1723 found_fin_ok:
1724 /* Process the FIN. */
1725 ++*seq;
1726 if (!(flags & MSG_PEEK)) {
1727 sk_eat_skb(sk, skb, copied_early);
1728 copied_early = 0;
1729 }
1730 break;
1731 } while (len > 0);
1732
1733 if (user_recv) {
1734 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1735 int chunk;
1736
1737 tp->ucopy.len = copied > 0 ? len : 0;
1738
1739 tcp_prequeue_process(sk);
1740
1741 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1742 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1743 len -= chunk;
1744 copied += chunk;
1745 }
1746 }
1747
1748 tp->ucopy.task = NULL;
1749 tp->ucopy.len = 0;
1750 }
1751
1752 #ifdef CONFIG_NET_DMA
1753 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1754 tp->ucopy.dma_chan = NULL;
1755
1756 if (tp->ucopy.pinned_list) {
1757 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1758 tp->ucopy.pinned_list = NULL;
1759 }
1760 #endif
1761
1762 /* According to UNIX98, msg_name/msg_namelen are ignored
1763 * on connected socket. I was just happy when found this 8) --ANK
1764 */
1765
1766 /* Clean up data we have read: This will do ACK frames. */
1767 tcp_cleanup_rbuf(sk, copied);
1768
1769 TCP_CHECK_TIMER(sk);
1770 release_sock(sk);
1771 return copied;
1772
1773 out:
1774 TCP_CHECK_TIMER(sk);
1775 release_sock(sk);
1776 return err;
1777
1778 recv_urg:
1779 err = tcp_recv_urg(sk, msg, len, flags);
1780 goto out;
1781 }
1782 EXPORT_SYMBOL(tcp_recvmsg);
1783
1784 void tcp_set_state(struct sock *sk, int state)
1785 {
1786 int oldstate = sk->sk_state;
1787
1788 switch (state) {
1789 case TCP_ESTABLISHED:
1790 if (oldstate != TCP_ESTABLISHED)
1791 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1792 break;
1793
1794 case TCP_CLOSE:
1795 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1796 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1797
1798 sk->sk_prot->unhash(sk);
1799 if (inet_csk(sk)->icsk_bind_hash &&
1800 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1801 inet_put_port(sk);
1802 /* fall through */
1803 default:
1804 if (oldstate == TCP_ESTABLISHED)
1805 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1806 }
1807
1808 /* Change state AFTER socket is unhashed to avoid closed
1809 * socket sitting in hash tables.
1810 */
1811 sk->sk_state = state;
1812
1813 #ifdef STATE_TRACE
1814 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1815 #endif
1816 }
1817 EXPORT_SYMBOL_GPL(tcp_set_state);
1818
1819 /*
1820 * State processing on a close. This implements the state shift for
1821 * sending our FIN frame. Note that we only send a FIN for some
1822 * states. A shutdown() may have already sent the FIN, or we may be
1823 * closed.
1824 */
1825
1826 static const unsigned char new_state[16] = {
1827 /* current state: new state: action: */
1828 /* (Invalid) */ TCP_CLOSE,
1829 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1830 /* TCP_SYN_SENT */ TCP_CLOSE,
1831 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1832 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1833 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1834 /* TCP_TIME_WAIT */ TCP_CLOSE,
1835 /* TCP_CLOSE */ TCP_CLOSE,
1836 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1837 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1838 /* TCP_LISTEN */ TCP_CLOSE,
1839 /* TCP_CLOSING */ TCP_CLOSING,
1840 };
1841
1842 static int tcp_close_state(struct sock *sk)
1843 {
1844 int next = (int)new_state[sk->sk_state];
1845 int ns = next & TCP_STATE_MASK;
1846
1847 tcp_set_state(sk, ns);
1848
1849 return next & TCP_ACTION_FIN;
1850 }
1851
1852 /*
1853 * Shutdown the sending side of a connection. Much like close except
1854 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1855 */
1856
1857 void tcp_shutdown(struct sock *sk, int how)
1858 {
1859 /* We need to grab some memory, and put together a FIN,
1860 * and then put it into the queue to be sent.
1861 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1862 */
1863 if (!(how & SEND_SHUTDOWN))
1864 return;
1865
1866 /* If we've already sent a FIN, or it's a closed state, skip this. */
1867 if ((1 << sk->sk_state) &
1868 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1869 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1870 /* Clear out any half completed packets. FIN if needed. */
1871 if (tcp_close_state(sk))
1872 tcp_send_fin(sk);
1873 }
1874 }
1875 EXPORT_SYMBOL(tcp_shutdown);
1876
1877 void tcp_close(struct sock *sk, long timeout)
1878 {
1879 struct sk_buff *skb;
1880 int data_was_unread = 0;
1881 int state;
1882
1883 lock_sock(sk);
1884 sk->sk_shutdown = SHUTDOWN_MASK;
1885
1886 if (sk->sk_state == TCP_LISTEN) {
1887 tcp_set_state(sk, TCP_CLOSE);
1888
1889 /* Special case. */
1890 inet_csk_listen_stop(sk);
1891
1892 goto adjudge_to_death;
1893 }
1894
1895 /* We need to flush the recv. buffs. We do this only on the
1896 * descriptor close, not protocol-sourced closes, because the
1897 * reader process may not have drained the data yet!
1898 */
1899 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1900 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1901 tcp_hdr(skb)->fin;
1902 data_was_unread += len;
1903 __kfree_skb(skb);
1904 }
1905
1906 sk_mem_reclaim(sk);
1907
1908 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1909 if (sk->sk_state == TCP_CLOSE)
1910 goto adjudge_to_death;
1911
1912 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1913 * data was lost. To witness the awful effects of the old behavior of
1914 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1915 * GET in an FTP client, suspend the process, wait for the client to
1916 * advertise a zero window, then kill -9 the FTP client, wheee...
1917 * Note: timeout is always zero in such a case.
1918 */
1919 if (data_was_unread) {
1920 /* Unread data was tossed, zap the connection. */
1921 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1922 tcp_set_state(sk, TCP_CLOSE);
1923 tcp_send_active_reset(sk, sk->sk_allocation);
1924 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1925 /* Check zero linger _after_ checking for unread data. */
1926 sk->sk_prot->disconnect(sk, 0);
1927 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1928 } else if (tcp_close_state(sk)) {
1929 /* We FIN if the application ate all the data before
1930 * zapping the connection.
1931 */
1932
1933 /* RED-PEN. Formally speaking, we have broken TCP state
1934 * machine. State transitions:
1935 *
1936 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1937 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1938 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1939 *
1940 * are legal only when FIN has been sent (i.e. in window),
1941 * rather than queued out of window. Purists blame.
1942 *
1943 * F.e. "RFC state" is ESTABLISHED,
1944 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1945 *
1946 * The visible declinations are that sometimes
1947 * we enter time-wait state, when it is not required really
1948 * (harmless), do not send active resets, when they are
1949 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1950 * they look as CLOSING or LAST_ACK for Linux)
1951 * Probably, I missed some more holelets.
1952 * --ANK
1953 */
1954 tcp_send_fin(sk);
1955 }
1956
1957 sk_stream_wait_close(sk, timeout);
1958
1959 adjudge_to_death:
1960 state = sk->sk_state;
1961 sock_hold(sk);
1962 sock_orphan(sk);
1963
1964 /* It is the last release_sock in its life. It will remove backlog. */
1965 release_sock(sk);
1966
1967
1968 /* Now socket is owned by kernel and we acquire BH lock
1969 to finish close. No need to check for user refs.
1970 */
1971 local_bh_disable();
1972 bh_lock_sock(sk);
1973 WARN_ON(sock_owned_by_user(sk));
1974
1975 percpu_counter_inc(sk->sk_prot->orphan_count);
1976
1977 /* Have we already been destroyed by a softirq or backlog? */
1978 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1979 goto out;
1980
1981 /* This is a (useful) BSD violating of the RFC. There is a
1982 * problem with TCP as specified in that the other end could
1983 * keep a socket open forever with no application left this end.
1984 * We use a 3 minute timeout (about the same as BSD) then kill
1985 * our end. If they send after that then tough - BUT: long enough
1986 * that we won't make the old 4*rto = almost no time - whoops
1987 * reset mistake.
1988 *
1989 * Nope, it was not mistake. It is really desired behaviour
1990 * f.e. on http servers, when such sockets are useless, but
1991 * consume significant resources. Let's do it with special
1992 * linger2 option. --ANK
1993 */
1994
1995 if (sk->sk_state == TCP_FIN_WAIT2) {
1996 struct tcp_sock *tp = tcp_sk(sk);
1997 if (tp->linger2 < 0) {
1998 tcp_set_state(sk, TCP_CLOSE);
1999 tcp_send_active_reset(sk, GFP_ATOMIC);
2000 NET_INC_STATS_BH(sock_net(sk),
2001 LINUX_MIB_TCPABORTONLINGER);
2002 } else {
2003 const int tmo = tcp_fin_time(sk);
2004
2005 if (tmo > TCP_TIMEWAIT_LEN) {
2006 inet_csk_reset_keepalive_timer(sk,
2007 tmo - TCP_TIMEWAIT_LEN);
2008 } else {
2009 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2010 goto out;
2011 }
2012 }
2013 }
2014 if (sk->sk_state != TCP_CLOSE) {
2015 sk_mem_reclaim(sk);
2016 if (tcp_too_many_orphans(sk, 0)) {
2017 if (net_ratelimit())
2018 printk(KERN_INFO "TCP: too many of orphaned "
2019 "sockets\n");
2020 tcp_set_state(sk, TCP_CLOSE);
2021 tcp_send_active_reset(sk, GFP_ATOMIC);
2022 NET_INC_STATS_BH(sock_net(sk),
2023 LINUX_MIB_TCPABORTONMEMORY);
2024 }
2025 }
2026
2027 if (sk->sk_state == TCP_CLOSE)
2028 inet_csk_destroy_sock(sk);
2029 /* Otherwise, socket is reprieved until protocol close. */
2030
2031 out:
2032 bh_unlock_sock(sk);
2033 local_bh_enable();
2034 sock_put(sk);
2035 }
2036 EXPORT_SYMBOL(tcp_close);
2037
2038 /* These states need RST on ABORT according to RFC793 */
2039
2040 static inline int tcp_need_reset(int state)
2041 {
2042 return (1 << state) &
2043 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2044 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2045 }
2046
2047 int tcp_disconnect(struct sock *sk, int flags)
2048 {
2049 struct inet_sock *inet = inet_sk(sk);
2050 struct inet_connection_sock *icsk = inet_csk(sk);
2051 struct tcp_sock *tp = tcp_sk(sk);
2052 int err = 0;
2053 int old_state = sk->sk_state;
2054
2055 if (old_state != TCP_CLOSE)
2056 tcp_set_state(sk, TCP_CLOSE);
2057
2058 /* ABORT function of RFC793 */
2059 if (old_state == TCP_LISTEN) {
2060 inet_csk_listen_stop(sk);
2061 } else if (tcp_need_reset(old_state) ||
2062 (tp->snd_nxt != tp->write_seq &&
2063 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2064 /* The last check adjusts for discrepancy of Linux wrt. RFC
2065 * states
2066 */
2067 tcp_send_active_reset(sk, gfp_any());
2068 sk->sk_err = ECONNRESET;
2069 } else if (old_state == TCP_SYN_SENT)
2070 sk->sk_err = ECONNRESET;
2071
2072 tcp_clear_xmit_timers(sk);
2073 __skb_queue_purge(&sk->sk_receive_queue);
2074 tcp_write_queue_purge(sk);
2075 __skb_queue_purge(&tp->out_of_order_queue);
2076 #ifdef CONFIG_NET_DMA
2077 __skb_queue_purge(&sk->sk_async_wait_queue);
2078 #endif
2079
2080 inet->inet_dport = 0;
2081
2082 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2083 inet_reset_saddr(sk);
2084
2085 sk->sk_shutdown = 0;
2086 sock_reset_flag(sk, SOCK_DONE);
2087 tp->srtt = 0;
2088 if ((tp->write_seq += tp->max_window + 2) == 0)
2089 tp->write_seq = 1;
2090 icsk->icsk_backoff = 0;
2091 tp->snd_cwnd = 2;
2092 icsk->icsk_probes_out = 0;
2093 tp->packets_out = 0;
2094 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2095 tp->snd_cwnd_cnt = 0;
2096 tp->bytes_acked = 0;
2097 tp->window_clamp = 0;
2098 tcp_set_ca_state(sk, TCP_CA_Open);
2099 tcp_clear_retrans(tp);
2100 inet_csk_delack_init(sk);
2101 tcp_init_send_head(sk);
2102 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2103 __sk_dst_reset(sk);
2104
2105 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2106
2107 sk->sk_error_report(sk);
2108 return err;
2109 }
2110 EXPORT_SYMBOL(tcp_disconnect);
2111
2112 /*
2113 * Socket option code for TCP.
2114 */
2115 static int do_tcp_setsockopt(struct sock *sk, int level,
2116 int optname, char __user *optval, unsigned int optlen)
2117 {
2118 struct tcp_sock *tp = tcp_sk(sk);
2119 struct inet_connection_sock *icsk = inet_csk(sk);
2120 int val;
2121 int err = 0;
2122
2123 /* These are data/string values, all the others are ints */
2124 switch (optname) {
2125 case TCP_CONGESTION: {
2126 char name[TCP_CA_NAME_MAX];
2127
2128 if (optlen < 1)
2129 return -EINVAL;
2130
2131 val = strncpy_from_user(name, optval,
2132 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2133 if (val < 0)
2134 return -EFAULT;
2135 name[val] = 0;
2136
2137 lock_sock(sk);
2138 err = tcp_set_congestion_control(sk, name);
2139 release_sock(sk);
2140 return err;
2141 }
2142 case TCP_COOKIE_TRANSACTIONS: {
2143 struct tcp_cookie_transactions ctd;
2144 struct tcp_cookie_values *cvp = NULL;
2145
2146 if (sizeof(ctd) > optlen)
2147 return -EINVAL;
2148 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2149 return -EFAULT;
2150
2151 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2152 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2153 return -EINVAL;
2154
2155 if (ctd.tcpct_cookie_desired == 0) {
2156 /* default to global value */
2157 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2158 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2159 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2160 return -EINVAL;
2161 }
2162
2163 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2164 /* Supercedes all other values */
2165 lock_sock(sk);
2166 if (tp->cookie_values != NULL) {
2167 kref_put(&tp->cookie_values->kref,
2168 tcp_cookie_values_release);
2169 tp->cookie_values = NULL;
2170 }
2171 tp->rx_opt.cookie_in_always = 0; /* false */
2172 tp->rx_opt.cookie_out_never = 1; /* true */
2173 release_sock(sk);
2174 return err;
2175 }
2176
2177 /* Allocate ancillary memory before locking.
2178 */
2179 if (ctd.tcpct_used > 0 ||
2180 (tp->cookie_values == NULL &&
2181 (sysctl_tcp_cookie_size > 0 ||
2182 ctd.tcpct_cookie_desired > 0 ||
2183 ctd.tcpct_s_data_desired > 0))) {
2184 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2185 GFP_KERNEL);
2186 if (cvp == NULL)
2187 return -ENOMEM;
2188
2189 kref_init(&cvp->kref);
2190 }
2191 lock_sock(sk);
2192 tp->rx_opt.cookie_in_always =
2193 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2194 tp->rx_opt.cookie_out_never = 0; /* false */
2195
2196 if (tp->cookie_values != NULL) {
2197 if (cvp != NULL) {
2198 /* Changed values are recorded by a changed
2199 * pointer, ensuring the cookie will differ,
2200 * without separately hashing each value later.
2201 */
2202 kref_put(&tp->cookie_values->kref,
2203 tcp_cookie_values_release);
2204 } else {
2205 cvp = tp->cookie_values;
2206 }
2207 }
2208
2209 if (cvp != NULL) {
2210 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2211
2212 if (ctd.tcpct_used > 0) {
2213 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2214 ctd.tcpct_used);
2215 cvp->s_data_desired = ctd.tcpct_used;
2216 cvp->s_data_constant = 1; /* true */
2217 } else {
2218 /* No constant payload data. */
2219 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2220 cvp->s_data_constant = 0; /* false */
2221 }
2222
2223 tp->cookie_values = cvp;
2224 }
2225 release_sock(sk);
2226 return err;
2227 }
2228 default:
2229 /* fallthru */
2230 break;
2231 }
2232
2233 if (optlen < sizeof(int))
2234 return -EINVAL;
2235
2236 if (get_user(val, (int __user *)optval))
2237 return -EFAULT;
2238
2239 lock_sock(sk);
2240
2241 switch (optname) {
2242 case TCP_MAXSEG:
2243 /* Values greater than interface MTU won't take effect. However
2244 * at the point when this call is done we typically don't yet
2245 * know which interface is going to be used */
2246 if (val < 8 || val > MAX_TCP_WINDOW) {
2247 err = -EINVAL;
2248 break;
2249 }
2250 tp->rx_opt.user_mss = val;
2251 break;
2252
2253 case TCP_NODELAY:
2254 if (val) {
2255 /* TCP_NODELAY is weaker than TCP_CORK, so that
2256 * this option on corked socket is remembered, but
2257 * it is not activated until cork is cleared.
2258 *
2259 * However, when TCP_NODELAY is set we make
2260 * an explicit push, which overrides even TCP_CORK
2261 * for currently queued segments.
2262 */
2263 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2264 tcp_push_pending_frames(sk);
2265 } else {
2266 tp->nonagle &= ~TCP_NAGLE_OFF;
2267 }
2268 break;
2269
2270 case TCP_THIN_LINEAR_TIMEOUTS:
2271 if (val < 0 || val > 1)
2272 err = -EINVAL;
2273 else
2274 tp->thin_lto = val;
2275 break;
2276
2277 case TCP_THIN_DUPACK:
2278 if (val < 0 || val > 1)
2279 err = -EINVAL;
2280 else
2281 tp->thin_dupack = val;
2282 break;
2283
2284 case TCP_CORK:
2285 /* When set indicates to always queue non-full frames.
2286 * Later the user clears this option and we transmit
2287 * any pending partial frames in the queue. This is
2288 * meant to be used alongside sendfile() to get properly
2289 * filled frames when the user (for example) must write
2290 * out headers with a write() call first and then use
2291 * sendfile to send out the data parts.
2292 *
2293 * TCP_CORK can be set together with TCP_NODELAY and it is
2294 * stronger than TCP_NODELAY.
2295 */
2296 if (val) {
2297 tp->nonagle |= TCP_NAGLE_CORK;
2298 } else {
2299 tp->nonagle &= ~TCP_NAGLE_CORK;
2300 if (tp->nonagle&TCP_NAGLE_OFF)
2301 tp->nonagle |= TCP_NAGLE_PUSH;
2302 tcp_push_pending_frames(sk);
2303 }
2304 break;
2305
2306 case TCP_KEEPIDLE:
2307 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2308 err = -EINVAL;
2309 else {
2310 tp->keepalive_time = val * HZ;
2311 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2312 !((1 << sk->sk_state) &
2313 (TCPF_CLOSE | TCPF_LISTEN))) {
2314 u32 elapsed = keepalive_time_elapsed(tp);
2315 if (tp->keepalive_time > elapsed)
2316 elapsed = tp->keepalive_time - elapsed;
2317 else
2318 elapsed = 0;
2319 inet_csk_reset_keepalive_timer(sk, elapsed);
2320 }
2321 }
2322 break;
2323 case TCP_KEEPINTVL:
2324 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2325 err = -EINVAL;
2326 else
2327 tp->keepalive_intvl = val * HZ;
2328 break;
2329 case TCP_KEEPCNT:
2330 if (val < 1 || val > MAX_TCP_KEEPCNT)
2331 err = -EINVAL;
2332 else
2333 tp->keepalive_probes = val;
2334 break;
2335 case TCP_SYNCNT:
2336 if (val < 1 || val > MAX_TCP_SYNCNT)
2337 err = -EINVAL;
2338 else
2339 icsk->icsk_syn_retries = val;
2340 break;
2341
2342 case TCP_LINGER2:
2343 if (val < 0)
2344 tp->linger2 = -1;
2345 else if (val > sysctl_tcp_fin_timeout / HZ)
2346 tp->linger2 = 0;
2347 else
2348 tp->linger2 = val * HZ;
2349 break;
2350
2351 case TCP_DEFER_ACCEPT:
2352 /* Translate value in seconds to number of retransmits */
2353 icsk->icsk_accept_queue.rskq_defer_accept =
2354 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2355 TCP_RTO_MAX / HZ);
2356 break;
2357
2358 case TCP_WINDOW_CLAMP:
2359 if (!val) {
2360 if (sk->sk_state != TCP_CLOSE) {
2361 err = -EINVAL;
2362 break;
2363 }
2364 tp->window_clamp = 0;
2365 } else
2366 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2367 SOCK_MIN_RCVBUF / 2 : val;
2368 break;
2369
2370 case TCP_QUICKACK:
2371 if (!val) {
2372 icsk->icsk_ack.pingpong = 1;
2373 } else {
2374 icsk->icsk_ack.pingpong = 0;
2375 if ((1 << sk->sk_state) &
2376 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2377 inet_csk_ack_scheduled(sk)) {
2378 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2379 tcp_cleanup_rbuf(sk, 1);
2380 if (!(val & 1))
2381 icsk->icsk_ack.pingpong = 1;
2382 }
2383 }
2384 break;
2385
2386 #ifdef CONFIG_TCP_MD5SIG
2387 case TCP_MD5SIG:
2388 /* Read the IP->Key mappings from userspace */
2389 err = tp->af_specific->md5_parse(sk, optval, optlen);
2390 break;
2391 #endif
2392
2393 default:
2394 err = -ENOPROTOOPT;
2395 break;
2396 }
2397
2398 release_sock(sk);
2399 return err;
2400 }
2401
2402 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2403 unsigned int optlen)
2404 {
2405 struct inet_connection_sock *icsk = inet_csk(sk);
2406
2407 if (level != SOL_TCP)
2408 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2409 optval, optlen);
2410 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2411 }
2412 EXPORT_SYMBOL(tcp_setsockopt);
2413
2414 #ifdef CONFIG_COMPAT
2415 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2416 char __user *optval, unsigned int optlen)
2417 {
2418 if (level != SOL_TCP)
2419 return inet_csk_compat_setsockopt(sk, level, optname,
2420 optval, optlen);
2421 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2422 }
2423 EXPORT_SYMBOL(compat_tcp_setsockopt);
2424 #endif
2425
2426 /* Return information about state of tcp endpoint in API format. */
2427 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2428 {
2429 struct tcp_sock *tp = tcp_sk(sk);
2430 const struct inet_connection_sock *icsk = inet_csk(sk);
2431 u32 now = tcp_time_stamp;
2432
2433 memset(info, 0, sizeof(*info));
2434
2435 info->tcpi_state = sk->sk_state;
2436 info->tcpi_ca_state = icsk->icsk_ca_state;
2437 info->tcpi_retransmits = icsk->icsk_retransmits;
2438 info->tcpi_probes = icsk->icsk_probes_out;
2439 info->tcpi_backoff = icsk->icsk_backoff;
2440
2441 if (tp->rx_opt.tstamp_ok)
2442 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2443 if (tcp_is_sack(tp))
2444 info->tcpi_options |= TCPI_OPT_SACK;
2445 if (tp->rx_opt.wscale_ok) {
2446 info->tcpi_options |= TCPI_OPT_WSCALE;
2447 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2448 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2449 }
2450
2451 if (tp->ecn_flags&TCP_ECN_OK)
2452 info->tcpi_options |= TCPI_OPT_ECN;
2453
2454 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2455 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2456 info->tcpi_snd_mss = tp->mss_cache;
2457 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2458
2459 if (sk->sk_state == TCP_LISTEN) {
2460 info->tcpi_unacked = sk->sk_ack_backlog;
2461 info->tcpi_sacked = sk->sk_max_ack_backlog;
2462 } else {
2463 info->tcpi_unacked = tp->packets_out;
2464 info->tcpi_sacked = tp->sacked_out;
2465 }
2466 info->tcpi_lost = tp->lost_out;
2467 info->tcpi_retrans = tp->retrans_out;
2468 info->tcpi_fackets = tp->fackets_out;
2469
2470 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2471 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2472 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2473
2474 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2475 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2476 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2477 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2478 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2479 info->tcpi_snd_cwnd = tp->snd_cwnd;
2480 info->tcpi_advmss = tp->advmss;
2481 info->tcpi_reordering = tp->reordering;
2482
2483 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2484 info->tcpi_rcv_space = tp->rcvq_space.space;
2485
2486 info->tcpi_total_retrans = tp->total_retrans;
2487 }
2488 EXPORT_SYMBOL_GPL(tcp_get_info);
2489
2490 static int do_tcp_getsockopt(struct sock *sk, int level,
2491 int optname, char __user *optval, int __user *optlen)
2492 {
2493 struct inet_connection_sock *icsk = inet_csk(sk);
2494 struct tcp_sock *tp = tcp_sk(sk);
2495 int val, len;
2496
2497 if (get_user(len, optlen))
2498 return -EFAULT;
2499
2500 len = min_t(unsigned int, len, sizeof(int));
2501
2502 if (len < 0)
2503 return -EINVAL;
2504
2505 switch (optname) {
2506 case TCP_MAXSEG:
2507 val = tp->mss_cache;
2508 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2509 val = tp->rx_opt.user_mss;
2510 break;
2511 case TCP_NODELAY:
2512 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2513 break;
2514 case TCP_CORK:
2515 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2516 break;
2517 case TCP_KEEPIDLE:
2518 val = keepalive_time_when(tp) / HZ;
2519 break;
2520 case TCP_KEEPINTVL:
2521 val = keepalive_intvl_when(tp) / HZ;
2522 break;
2523 case TCP_KEEPCNT:
2524 val = keepalive_probes(tp);
2525 break;
2526 case TCP_SYNCNT:
2527 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2528 break;
2529 case TCP_LINGER2:
2530 val = tp->linger2;
2531 if (val >= 0)
2532 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2533 break;
2534 case TCP_DEFER_ACCEPT:
2535 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2536 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2537 break;
2538 case TCP_WINDOW_CLAMP:
2539 val = tp->window_clamp;
2540 break;
2541 case TCP_INFO: {
2542 struct tcp_info info;
2543
2544 if (get_user(len, optlen))
2545 return -EFAULT;
2546
2547 tcp_get_info(sk, &info);
2548
2549 len = min_t(unsigned int, len, sizeof(info));
2550 if (put_user(len, optlen))
2551 return -EFAULT;
2552 if (copy_to_user(optval, &info, len))
2553 return -EFAULT;
2554 return 0;
2555 }
2556 case TCP_QUICKACK:
2557 val = !icsk->icsk_ack.pingpong;
2558 break;
2559
2560 case TCP_CONGESTION:
2561 if (get_user(len, optlen))
2562 return -EFAULT;
2563 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2564 if (put_user(len, optlen))
2565 return -EFAULT;
2566 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2567 return -EFAULT;
2568 return 0;
2569
2570 case TCP_COOKIE_TRANSACTIONS: {
2571 struct tcp_cookie_transactions ctd;
2572 struct tcp_cookie_values *cvp = tp->cookie_values;
2573
2574 if (get_user(len, optlen))
2575 return -EFAULT;
2576 if (len < sizeof(ctd))
2577 return -EINVAL;
2578
2579 memset(&ctd, 0, sizeof(ctd));
2580 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2581 TCP_COOKIE_IN_ALWAYS : 0)
2582 | (tp->rx_opt.cookie_out_never ?
2583 TCP_COOKIE_OUT_NEVER : 0);
2584
2585 if (cvp != NULL) {
2586 ctd.tcpct_flags |= (cvp->s_data_in ?
2587 TCP_S_DATA_IN : 0)
2588 | (cvp->s_data_out ?
2589 TCP_S_DATA_OUT : 0);
2590
2591 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2592 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2593
2594 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2595 cvp->cookie_pair_size);
2596 ctd.tcpct_used = cvp->cookie_pair_size;
2597 }
2598
2599 if (put_user(sizeof(ctd), optlen))
2600 return -EFAULT;
2601 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2602 return -EFAULT;
2603 return 0;
2604 }
2605 case TCP_THIN_LINEAR_TIMEOUTS:
2606 val = tp->thin_lto;
2607 break;
2608 case TCP_THIN_DUPACK:
2609 val = tp->thin_dupack;
2610 break;
2611 default:
2612 return -ENOPROTOOPT;
2613 }
2614
2615 if (put_user(len, optlen))
2616 return -EFAULT;
2617 if (copy_to_user(optval, &val, len))
2618 return -EFAULT;
2619 return 0;
2620 }
2621
2622 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2623 int __user *optlen)
2624 {
2625 struct inet_connection_sock *icsk = inet_csk(sk);
2626
2627 if (level != SOL_TCP)
2628 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2629 optval, optlen);
2630 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2631 }
2632 EXPORT_SYMBOL(tcp_getsockopt);
2633
2634 #ifdef CONFIG_COMPAT
2635 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2636 char __user *optval, int __user *optlen)
2637 {
2638 if (level != SOL_TCP)
2639 return inet_csk_compat_getsockopt(sk, level, optname,
2640 optval, optlen);
2641 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2642 }
2643 EXPORT_SYMBOL(compat_tcp_getsockopt);
2644 #endif
2645
2646 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2647 {
2648 struct sk_buff *segs = ERR_PTR(-EINVAL);
2649 struct tcphdr *th;
2650 unsigned thlen;
2651 unsigned int seq;
2652 __be32 delta;
2653 unsigned int oldlen;
2654 unsigned int mss;
2655
2656 if (!pskb_may_pull(skb, sizeof(*th)))
2657 goto out;
2658
2659 th = tcp_hdr(skb);
2660 thlen = th->doff * 4;
2661 if (thlen < sizeof(*th))
2662 goto out;
2663
2664 if (!pskb_may_pull(skb, thlen))
2665 goto out;
2666
2667 oldlen = (u16)~skb->len;
2668 __skb_pull(skb, thlen);
2669
2670 mss = skb_shinfo(skb)->gso_size;
2671 if (unlikely(skb->len <= mss))
2672 goto out;
2673
2674 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2675 /* Packet is from an untrusted source, reset gso_segs. */
2676 int type = skb_shinfo(skb)->gso_type;
2677
2678 if (unlikely(type &
2679 ~(SKB_GSO_TCPV4 |
2680 SKB_GSO_DODGY |
2681 SKB_GSO_TCP_ECN |
2682 SKB_GSO_TCPV6 |
2683 0) ||
2684 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2685 goto out;
2686
2687 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2688
2689 segs = NULL;
2690 goto out;
2691 }
2692
2693 segs = skb_segment(skb, features);
2694 if (IS_ERR(segs))
2695 goto out;
2696
2697 delta = htonl(oldlen + (thlen + mss));
2698
2699 skb = segs;
2700 th = tcp_hdr(skb);
2701 seq = ntohl(th->seq);
2702
2703 do {
2704 th->fin = th->psh = 0;
2705
2706 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2707 (__force u32)delta));
2708 if (skb->ip_summed != CHECKSUM_PARTIAL)
2709 th->check =
2710 csum_fold(csum_partial(skb_transport_header(skb),
2711 thlen, skb->csum));
2712
2713 seq += mss;
2714 skb = skb->next;
2715 th = tcp_hdr(skb);
2716
2717 th->seq = htonl(seq);
2718 th->cwr = 0;
2719 } while (skb->next);
2720
2721 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2722 skb->data_len);
2723 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2724 (__force u32)delta));
2725 if (skb->ip_summed != CHECKSUM_PARTIAL)
2726 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2727 thlen, skb->csum));
2728
2729 out:
2730 return segs;
2731 }
2732 EXPORT_SYMBOL(tcp_tso_segment);
2733
2734 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2735 {
2736 struct sk_buff **pp = NULL;
2737 struct sk_buff *p;
2738 struct tcphdr *th;
2739 struct tcphdr *th2;
2740 unsigned int len;
2741 unsigned int thlen;
2742 __be32 flags;
2743 unsigned int mss = 1;
2744 unsigned int hlen;
2745 unsigned int off;
2746 int flush = 1;
2747 int i;
2748
2749 off = skb_gro_offset(skb);
2750 hlen = off + sizeof(*th);
2751 th = skb_gro_header_fast(skb, off);
2752 if (skb_gro_header_hard(skb, hlen)) {
2753 th = skb_gro_header_slow(skb, hlen, off);
2754 if (unlikely(!th))
2755 goto out;
2756 }
2757
2758 thlen = th->doff * 4;
2759 if (thlen < sizeof(*th))
2760 goto out;
2761
2762 hlen = off + thlen;
2763 if (skb_gro_header_hard(skb, hlen)) {
2764 th = skb_gro_header_slow(skb, hlen, off);
2765 if (unlikely(!th))
2766 goto out;
2767 }
2768
2769 skb_gro_pull(skb, thlen);
2770
2771 len = skb_gro_len(skb);
2772 flags = tcp_flag_word(th);
2773
2774 for (; (p = *head); head = &p->next) {
2775 if (!NAPI_GRO_CB(p)->same_flow)
2776 continue;
2777
2778 th2 = tcp_hdr(p);
2779
2780 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2781 NAPI_GRO_CB(p)->same_flow = 0;
2782 continue;
2783 }
2784
2785 goto found;
2786 }
2787
2788 goto out_check_final;
2789
2790 found:
2791 flush = NAPI_GRO_CB(p)->flush;
2792 flush |= (__force int)(flags & TCP_FLAG_CWR);
2793 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2794 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2795 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2796 for (i = sizeof(*th); i < thlen; i += 4)
2797 flush |= *(u32 *)((u8 *)th + i) ^
2798 *(u32 *)((u8 *)th2 + i);
2799
2800 mss = skb_shinfo(p)->gso_size;
2801
2802 flush |= (len - 1) >= mss;
2803 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2804
2805 if (flush || skb_gro_receive(head, skb)) {
2806 mss = 1;
2807 goto out_check_final;
2808 }
2809
2810 p = *head;
2811 th2 = tcp_hdr(p);
2812 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2813
2814 out_check_final:
2815 flush = len < mss;
2816 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2817 TCP_FLAG_RST | TCP_FLAG_SYN |
2818 TCP_FLAG_FIN));
2819
2820 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2821 pp = head;
2822
2823 out:
2824 NAPI_GRO_CB(skb)->flush |= flush;
2825
2826 return pp;
2827 }
2828 EXPORT_SYMBOL(tcp_gro_receive);
2829
2830 int tcp_gro_complete(struct sk_buff *skb)
2831 {
2832 struct tcphdr *th = tcp_hdr(skb);
2833
2834 skb->csum_start = skb_transport_header(skb) - skb->head;
2835 skb->csum_offset = offsetof(struct tcphdr, check);
2836 skb->ip_summed = CHECKSUM_PARTIAL;
2837
2838 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2839
2840 if (th->cwr)
2841 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2842
2843 return 0;
2844 }
2845 EXPORT_SYMBOL(tcp_gro_complete);
2846
2847 #ifdef CONFIG_TCP_MD5SIG
2848 static unsigned long tcp_md5sig_users;
2849 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2850 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2851
2852 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2853 {
2854 int cpu;
2855 for_each_possible_cpu(cpu) {
2856 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2857 if (p) {
2858 if (p->md5_desc.tfm)
2859 crypto_free_hash(p->md5_desc.tfm);
2860 kfree(p);
2861 }
2862 }
2863 free_percpu(pool);
2864 }
2865
2866 void tcp_free_md5sig_pool(void)
2867 {
2868 struct tcp_md5sig_pool * __percpu *pool = NULL;
2869
2870 spin_lock_bh(&tcp_md5sig_pool_lock);
2871 if (--tcp_md5sig_users == 0) {
2872 pool = tcp_md5sig_pool;
2873 tcp_md5sig_pool = NULL;
2874 }
2875 spin_unlock_bh(&tcp_md5sig_pool_lock);
2876 if (pool)
2877 __tcp_free_md5sig_pool(pool);
2878 }
2879 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2880
2881 static struct tcp_md5sig_pool * __percpu *
2882 __tcp_alloc_md5sig_pool(struct sock *sk)
2883 {
2884 int cpu;
2885 struct tcp_md5sig_pool * __percpu *pool;
2886
2887 pool = alloc_percpu(struct tcp_md5sig_pool *);
2888 if (!pool)
2889 return NULL;
2890
2891 for_each_possible_cpu(cpu) {
2892 struct tcp_md5sig_pool *p;
2893 struct crypto_hash *hash;
2894
2895 p = kzalloc(sizeof(*p), sk->sk_allocation);
2896 if (!p)
2897 goto out_free;
2898 *per_cpu_ptr(pool, cpu) = p;
2899
2900 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2901 if (!hash || IS_ERR(hash))
2902 goto out_free;
2903
2904 p->md5_desc.tfm = hash;
2905 }
2906 return pool;
2907 out_free:
2908 __tcp_free_md5sig_pool(pool);
2909 return NULL;
2910 }
2911
2912 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2913 {
2914 struct tcp_md5sig_pool * __percpu *pool;
2915 int alloc = 0;
2916
2917 retry:
2918 spin_lock_bh(&tcp_md5sig_pool_lock);
2919 pool = tcp_md5sig_pool;
2920 if (tcp_md5sig_users++ == 0) {
2921 alloc = 1;
2922 spin_unlock_bh(&tcp_md5sig_pool_lock);
2923 } else if (!pool) {
2924 tcp_md5sig_users--;
2925 spin_unlock_bh(&tcp_md5sig_pool_lock);
2926 cpu_relax();
2927 goto retry;
2928 } else
2929 spin_unlock_bh(&tcp_md5sig_pool_lock);
2930
2931 if (alloc) {
2932 /* we cannot hold spinlock here because this may sleep. */
2933 struct tcp_md5sig_pool * __percpu *p;
2934
2935 p = __tcp_alloc_md5sig_pool(sk);
2936 spin_lock_bh(&tcp_md5sig_pool_lock);
2937 if (!p) {
2938 tcp_md5sig_users--;
2939 spin_unlock_bh(&tcp_md5sig_pool_lock);
2940 return NULL;
2941 }
2942 pool = tcp_md5sig_pool;
2943 if (pool) {
2944 /* oops, it has already been assigned. */
2945 spin_unlock_bh(&tcp_md5sig_pool_lock);
2946 __tcp_free_md5sig_pool(p);
2947 } else {
2948 tcp_md5sig_pool = pool = p;
2949 spin_unlock_bh(&tcp_md5sig_pool_lock);
2950 }
2951 }
2952 return pool;
2953 }
2954 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2955
2956
2957 /**
2958 * tcp_get_md5sig_pool - get md5sig_pool for this user
2959 *
2960 * We use percpu structure, so if we succeed, we exit with preemption
2961 * and BH disabled, to make sure another thread or softirq handling
2962 * wont try to get same context.
2963 */
2964 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2965 {
2966 struct tcp_md5sig_pool * __percpu *p;
2967
2968 local_bh_disable();
2969
2970 spin_lock(&tcp_md5sig_pool_lock);
2971 p = tcp_md5sig_pool;
2972 if (p)
2973 tcp_md5sig_users++;
2974 spin_unlock(&tcp_md5sig_pool_lock);
2975
2976 if (p)
2977 return *this_cpu_ptr(p);
2978
2979 local_bh_enable();
2980 return NULL;
2981 }
2982 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2983
2984 void tcp_put_md5sig_pool(void)
2985 {
2986 local_bh_enable();
2987 tcp_free_md5sig_pool();
2988 }
2989 EXPORT_SYMBOL(tcp_put_md5sig_pool);
2990
2991 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2992 struct tcphdr *th)
2993 {
2994 struct scatterlist sg;
2995 int err;
2996
2997 __sum16 old_checksum = th->check;
2998 th->check = 0;
2999 /* options aren't included in the hash */
3000 sg_init_one(&sg, th, sizeof(struct tcphdr));
3001 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
3002 th->check = old_checksum;
3003 return err;
3004 }
3005 EXPORT_SYMBOL(tcp_md5_hash_header);
3006
3007 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3008 struct sk_buff *skb, unsigned header_len)
3009 {
3010 struct scatterlist sg;
3011 const struct tcphdr *tp = tcp_hdr(skb);
3012 struct hash_desc *desc = &hp->md5_desc;
3013 unsigned i;
3014 const unsigned head_data_len = skb_headlen(skb) > header_len ?
3015 skb_headlen(skb) - header_len : 0;
3016 const struct skb_shared_info *shi = skb_shinfo(skb);
3017 struct sk_buff *frag_iter;
3018
3019 sg_init_table(&sg, 1);
3020
3021 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3022 if (crypto_hash_update(desc, &sg, head_data_len))
3023 return 1;
3024
3025 for (i = 0; i < shi->nr_frags; ++i) {
3026 const struct skb_frag_struct *f = &shi->frags[i];
3027 sg_set_page(&sg, f->page, f->size, f->page_offset);
3028 if (crypto_hash_update(desc, &sg, f->size))
3029 return 1;
3030 }
3031
3032 skb_walk_frags(skb, frag_iter)
3033 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3034 return 1;
3035
3036 return 0;
3037 }
3038 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3039
3040 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3041 {
3042 struct scatterlist sg;
3043
3044 sg_init_one(&sg, key->key, key->keylen);
3045 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3046 }
3047 EXPORT_SYMBOL(tcp_md5_hash_key);
3048
3049 #endif
3050
3051 /**
3052 * Each Responder maintains up to two secret values concurrently for
3053 * efficient secret rollover. Each secret value has 4 states:
3054 *
3055 * Generating. (tcp_secret_generating != tcp_secret_primary)
3056 * Generates new Responder-Cookies, but not yet used for primary
3057 * verification. This is a short-term state, typically lasting only
3058 * one round trip time (RTT).
3059 *
3060 * Primary. (tcp_secret_generating == tcp_secret_primary)
3061 * Used both for generation and primary verification.
3062 *
3063 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3064 * Used for verification, until the first failure that can be
3065 * verified by the newer Generating secret. At that time, this
3066 * cookie's state is changed to Secondary, and the Generating
3067 * cookie's state is changed to Primary. This is a short-term state,
3068 * typically lasting only one round trip time (RTT).
3069 *
3070 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3071 * Used for secondary verification, after primary verification
3072 * failures. This state lasts no more than twice the Maximum Segment
3073 * Lifetime (2MSL). Then, the secret is discarded.
3074 */
3075 struct tcp_cookie_secret {
3076 /* The secret is divided into two parts. The digest part is the
3077 * equivalent of previously hashing a secret and saving the state,
3078 * and serves as an initialization vector (IV). The message part
3079 * serves as the trailing secret.
3080 */
3081 u32 secrets[COOKIE_WORKSPACE_WORDS];
3082 unsigned long expires;
3083 };
3084
3085 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3086 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3087 #define TCP_SECRET_LIFE (HZ * 600)
3088
3089 static struct tcp_cookie_secret tcp_secret_one;
3090 static struct tcp_cookie_secret tcp_secret_two;
3091
3092 /* Essentially a circular list, without dynamic allocation. */
3093 static struct tcp_cookie_secret *tcp_secret_generating;
3094 static struct tcp_cookie_secret *tcp_secret_primary;
3095 static struct tcp_cookie_secret *tcp_secret_retiring;
3096 static struct tcp_cookie_secret *tcp_secret_secondary;
3097
3098 static DEFINE_SPINLOCK(tcp_secret_locker);
3099
3100 /* Select a pseudo-random word in the cookie workspace.
3101 */
3102 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3103 {
3104 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3105 }
3106
3107 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3108 * Called in softirq context.
3109 * Returns: 0 for success.
3110 */
3111 int tcp_cookie_generator(u32 *bakery)
3112 {
3113 unsigned long jiffy = jiffies;
3114
3115 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3116 spin_lock_bh(&tcp_secret_locker);
3117 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3118 /* refreshed by another */
3119 memcpy(bakery,
3120 &tcp_secret_generating->secrets[0],
3121 COOKIE_WORKSPACE_WORDS);
3122 } else {
3123 /* still needs refreshing */
3124 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3125
3126 /* The first time, paranoia assumes that the
3127 * randomization function isn't as strong. But,
3128 * this secret initialization is delayed until
3129 * the last possible moment (packet arrival).
3130 * Although that time is observable, it is
3131 * unpredictably variable. Mash in the most
3132 * volatile clock bits available, and expire the
3133 * secret extra quickly.
3134 */
3135 if (unlikely(tcp_secret_primary->expires ==
3136 tcp_secret_secondary->expires)) {
3137 struct timespec tv;
3138
3139 getnstimeofday(&tv);
3140 bakery[COOKIE_DIGEST_WORDS+0] ^=
3141 (u32)tv.tv_nsec;
3142
3143 tcp_secret_secondary->expires = jiffy
3144 + TCP_SECRET_1MSL
3145 + (0x0f & tcp_cookie_work(bakery, 0));
3146 } else {
3147 tcp_secret_secondary->expires = jiffy
3148 + TCP_SECRET_LIFE
3149 + (0xff & tcp_cookie_work(bakery, 1));
3150 tcp_secret_primary->expires = jiffy
3151 + TCP_SECRET_2MSL
3152 + (0x1f & tcp_cookie_work(bakery, 2));
3153 }
3154 memcpy(&tcp_secret_secondary->secrets[0],
3155 bakery, COOKIE_WORKSPACE_WORDS);
3156
3157 rcu_assign_pointer(tcp_secret_generating,
3158 tcp_secret_secondary);
3159 rcu_assign_pointer(tcp_secret_retiring,
3160 tcp_secret_primary);
3161 /*
3162 * Neither call_rcu() nor synchronize_rcu() needed.
3163 * Retiring data is not freed. It is replaced after
3164 * further (locked) pointer updates, and a quiet time
3165 * (minimum 1MSL, maximum LIFE - 2MSL).
3166 */
3167 }
3168 spin_unlock_bh(&tcp_secret_locker);
3169 } else {
3170 rcu_read_lock_bh();
3171 memcpy(bakery,
3172 &rcu_dereference(tcp_secret_generating)->secrets[0],
3173 COOKIE_WORKSPACE_WORDS);
3174 rcu_read_unlock_bh();
3175 }
3176 return 0;
3177 }
3178 EXPORT_SYMBOL(tcp_cookie_generator);
3179
3180 void tcp_done(struct sock *sk)
3181 {
3182 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3183 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3184
3185 tcp_set_state(sk, TCP_CLOSE);
3186 tcp_clear_xmit_timers(sk);
3187
3188 sk->sk_shutdown = SHUTDOWN_MASK;
3189
3190 if (!sock_flag(sk, SOCK_DEAD))
3191 sk->sk_state_change(sk);
3192 else
3193 inet_csk_destroy_sock(sk);
3194 }
3195 EXPORT_SYMBOL_GPL(tcp_done);
3196
3197 extern struct tcp_congestion_ops tcp_reno;
3198
3199 static __initdata unsigned long thash_entries;
3200 static int __init set_thash_entries(char *str)
3201 {
3202 if (!str)
3203 return 0;
3204 thash_entries = simple_strtoul(str, &str, 0);
3205 return 1;
3206 }
3207 __setup("thash_entries=", set_thash_entries);
3208
3209 void __init tcp_init(void)
3210 {
3211 struct sk_buff *skb = NULL;
3212 unsigned long nr_pages, limit;
3213 int i, max_share, cnt;
3214 unsigned long jiffy = jiffies;
3215
3216 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3217
3218 percpu_counter_init(&tcp_sockets_allocated, 0);
3219 percpu_counter_init(&tcp_orphan_count, 0);
3220 tcp_hashinfo.bind_bucket_cachep =
3221 kmem_cache_create("tcp_bind_bucket",
3222 sizeof(struct inet_bind_bucket), 0,
3223 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3224
3225 /* Size and allocate the main established and bind bucket
3226 * hash tables.
3227 *
3228 * The methodology is similar to that of the buffer cache.
3229 */
3230 tcp_hashinfo.ehash =
3231 alloc_large_system_hash("TCP established",
3232 sizeof(struct inet_ehash_bucket),
3233 thash_entries,
3234 (totalram_pages >= 128 * 1024) ?
3235 13 : 15,
3236 0,
3237 NULL,
3238 &tcp_hashinfo.ehash_mask,
3239 thash_entries ? 0 : 512 * 1024);
3240 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3241 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3242 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3243 }
3244 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3245 panic("TCP: failed to alloc ehash_locks");
3246 tcp_hashinfo.bhash =
3247 alloc_large_system_hash("TCP bind",
3248 sizeof(struct inet_bind_hashbucket),
3249 tcp_hashinfo.ehash_mask + 1,
3250 (totalram_pages >= 128 * 1024) ?
3251 13 : 15,
3252 0,
3253 &tcp_hashinfo.bhash_size,
3254 NULL,
3255 64 * 1024);
3256 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3257 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3258 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3259 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3260 }
3261
3262
3263 cnt = tcp_hashinfo.ehash_mask + 1;
3264
3265 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3266 sysctl_tcp_max_orphans = cnt / 2;
3267 sysctl_max_syn_backlog = max(128, cnt / 256);
3268
3269 /* Set the pressure threshold to be a fraction of global memory that
3270 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3271 * memory, with a floor of 128 pages.
3272 */
3273 nr_pages = totalram_pages - totalhigh_pages;
3274 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3275 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3276 limit = max(limit, 128UL);
3277 sysctl_tcp_mem[0] = limit / 4 * 3;
3278 sysctl_tcp_mem[1] = limit;
3279 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3280
3281 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3282 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3283 max_share = min(4UL*1024*1024, limit);
3284
3285 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3286 sysctl_tcp_wmem[1] = 16*1024;
3287 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3288
3289 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3290 sysctl_tcp_rmem[1] = 87380;
3291 sysctl_tcp_rmem[2] = max(87380, max_share);
3292
3293 printk(KERN_INFO "TCP: Hash tables configured "
3294 "(established %u bind %u)\n",
3295 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3296
3297 tcp_register_congestion_control(&tcp_reno);
3298
3299 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3300 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3301 tcp_secret_one.expires = jiffy; /* past due */
3302 tcp_secret_two.expires = jiffy; /* past due */
3303 tcp_secret_generating = &tcp_secret_one;
3304 tcp_secret_primary = &tcp_secret_one;
3305 tcp_secret_retiring = &tcp_secret_two;
3306 tcp_secret_secondary = &tcp_secret_two;
3307 }
Linux with added FPC-III support