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tcp: prepare CC get_info() access from getsockopt()
[deliverable/linux.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * 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 #define pr_fmt(fmt) "TCP: " fmt
249
250 #include <linux/kernel.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/fs.h>
257 #include <linux/skbuff.h>
258 #include <linux/scatterlist.h>
259 #include <linux/splice.h>
260 #include <linux/net.h>
261 #include <linux/socket.h>
262 #include <linux/random.h>
263 #include <linux/bootmem.h>
264 #include <linux/highmem.h>
265 #include <linux/swap.h>
266 #include <linux/cache.h>
267 #include <linux/err.h>
268 #include <linux/crypto.h>
269 #include <linux/time.h>
270 #include <linux/slab.h>
271
272 #include <net/icmp.h>
273 #include <net/inet_common.h>
274 #include <net/tcp.h>
275 #include <net/xfrm.h>
276 #include <net/ip.h>
277 #include <net/sock.h>
278
279 #include <asm/uaccess.h>
280 #include <asm/ioctls.h>
281 #include <net/busy_poll.h>
282
283 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
284
285 int sysctl_tcp_min_tso_segs __read_mostly = 2;
286
287 int sysctl_tcp_autocorking __read_mostly = 1;
288
289 struct percpu_counter tcp_orphan_count;
290 EXPORT_SYMBOL_GPL(tcp_orphan_count);
291
292 long sysctl_tcp_mem[3] __read_mostly;
293 int sysctl_tcp_wmem[3] __read_mostly;
294 int sysctl_tcp_rmem[3] __read_mostly;
295
296 EXPORT_SYMBOL(sysctl_tcp_mem);
297 EXPORT_SYMBOL(sysctl_tcp_rmem);
298 EXPORT_SYMBOL(sysctl_tcp_wmem);
299
300 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
301 EXPORT_SYMBOL(tcp_memory_allocated);
302
303 /*
304 * Current number of TCP sockets.
305 */
306 struct percpu_counter tcp_sockets_allocated;
307 EXPORT_SYMBOL(tcp_sockets_allocated);
308
309 /*
310 * TCP splice context
311 */
312 struct tcp_splice_state {
313 struct pipe_inode_info *pipe;
314 size_t len;
315 unsigned int flags;
316 };
317
318 /*
319 * Pressure flag: try to collapse.
320 * Technical note: it is used by multiple contexts non atomically.
321 * All the __sk_mem_schedule() is of this nature: accounting
322 * is strict, actions are advisory and have some latency.
323 */
324 int tcp_memory_pressure __read_mostly;
325 EXPORT_SYMBOL(tcp_memory_pressure);
326
327 void tcp_enter_memory_pressure(struct sock *sk)
328 {
329 if (!tcp_memory_pressure) {
330 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
331 tcp_memory_pressure = 1;
332 }
333 }
334 EXPORT_SYMBOL(tcp_enter_memory_pressure);
335
336 /* Convert seconds to retransmits based on initial and max timeout */
337 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
338 {
339 u8 res = 0;
340
341 if (seconds > 0) {
342 int period = timeout;
343
344 res = 1;
345 while (seconds > period && res < 255) {
346 res++;
347 timeout <<= 1;
348 if (timeout > rto_max)
349 timeout = rto_max;
350 period += timeout;
351 }
352 }
353 return res;
354 }
355
356 /* Convert retransmits to seconds based on initial and max timeout */
357 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
358 {
359 int period = 0;
360
361 if (retrans > 0) {
362 period = timeout;
363 while (--retrans) {
364 timeout <<= 1;
365 if (timeout > rto_max)
366 timeout = rto_max;
367 period += timeout;
368 }
369 }
370 return period;
371 }
372
373 /* Address-family independent initialization for a tcp_sock.
374 *
375 * NOTE: A lot of things set to zero explicitly by call to
376 * sk_alloc() so need not be done here.
377 */
378 void tcp_init_sock(struct sock *sk)
379 {
380 struct inet_connection_sock *icsk = inet_csk(sk);
381 struct tcp_sock *tp = tcp_sk(sk);
382
383 __skb_queue_head_init(&tp->out_of_order_queue);
384 tcp_init_xmit_timers(sk);
385 tcp_prequeue_init(tp);
386 INIT_LIST_HEAD(&tp->tsq_node);
387
388 icsk->icsk_rto = TCP_TIMEOUT_INIT;
389 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
390
391 /* So many TCP implementations out there (incorrectly) count the
392 * initial SYN frame in their delayed-ACK and congestion control
393 * algorithms that we must have the following bandaid to talk
394 * efficiently to them. -DaveM
395 */
396 tp->snd_cwnd = TCP_INIT_CWND;
397
398 /* See draft-stevens-tcpca-spec-01 for discussion of the
399 * initialization of these values.
400 */
401 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
402 tp->snd_cwnd_clamp = ~0;
403 tp->mss_cache = TCP_MSS_DEFAULT;
404
405 tp->reordering = sysctl_tcp_reordering;
406 tcp_enable_early_retrans(tp);
407 tcp_assign_congestion_control(sk);
408
409 tp->tsoffset = 0;
410
411 sk->sk_state = TCP_CLOSE;
412
413 sk->sk_write_space = sk_stream_write_space;
414 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
415
416 icsk->icsk_sync_mss = tcp_sync_mss;
417
418 sk->sk_sndbuf = sysctl_tcp_wmem[1];
419 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
420
421 local_bh_disable();
422 sock_update_memcg(sk);
423 sk_sockets_allocated_inc(sk);
424 local_bh_enable();
425 }
426 EXPORT_SYMBOL(tcp_init_sock);
427
428 static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
429 {
430 if (sk->sk_tsflags) {
431 struct skb_shared_info *shinfo = skb_shinfo(skb);
432
433 sock_tx_timestamp(sk, &shinfo->tx_flags);
434 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
435 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
436 }
437 }
438
439 /*
440 * Wait for a TCP event.
441 *
442 * Note that we don't need to lock the socket, as the upper poll layers
443 * take care of normal races (between the test and the event) and we don't
444 * go look at any of the socket buffers directly.
445 */
446 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
447 {
448 unsigned int mask;
449 struct sock *sk = sock->sk;
450 const struct tcp_sock *tp = tcp_sk(sk);
451
452 sock_rps_record_flow(sk);
453
454 sock_poll_wait(file, sk_sleep(sk), wait);
455 if (sk->sk_state == TCP_LISTEN)
456 return inet_csk_listen_poll(sk);
457
458 /* Socket is not locked. We are protected from async events
459 * by poll logic and correct handling of state changes
460 * made by other threads is impossible in any case.
461 */
462
463 mask = 0;
464
465 /*
466 * POLLHUP is certainly not done right. But poll() doesn't
467 * have a notion of HUP in just one direction, and for a
468 * socket the read side is more interesting.
469 *
470 * Some poll() documentation says that POLLHUP is incompatible
471 * with the POLLOUT/POLLWR flags, so somebody should check this
472 * all. But careful, it tends to be safer to return too many
473 * bits than too few, and you can easily break real applications
474 * if you don't tell them that something has hung up!
475 *
476 * Check-me.
477 *
478 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
479 * our fs/select.c). It means that after we received EOF,
480 * poll always returns immediately, making impossible poll() on write()
481 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
482 * if and only if shutdown has been made in both directions.
483 * Actually, it is interesting to look how Solaris and DUX
484 * solve this dilemma. I would prefer, if POLLHUP were maskable,
485 * then we could set it on SND_SHUTDOWN. BTW examples given
486 * in Stevens' books assume exactly this behaviour, it explains
487 * why POLLHUP is incompatible with POLLOUT. --ANK
488 *
489 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
490 * blocking on fresh not-connected or disconnected socket. --ANK
491 */
492 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
493 mask |= POLLHUP;
494 if (sk->sk_shutdown & RCV_SHUTDOWN)
495 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
496
497 /* Connected or passive Fast Open socket? */
498 if (sk->sk_state != TCP_SYN_SENT &&
499 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk)) {
500 int target = sock_rcvlowat(sk, 0, INT_MAX);
501
502 if (tp->urg_seq == tp->copied_seq &&
503 !sock_flag(sk, SOCK_URGINLINE) &&
504 tp->urg_data)
505 target++;
506
507 /* Potential race condition. If read of tp below will
508 * escape above sk->sk_state, we can be illegally awaken
509 * in SYN_* states. */
510 if (tp->rcv_nxt - tp->copied_seq >= target)
511 mask |= POLLIN | POLLRDNORM;
512
513 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
514 if (sk_stream_is_writeable(sk)) {
515 mask |= POLLOUT | POLLWRNORM;
516 } else { /* send SIGIO later */
517 set_bit(SOCK_ASYNC_NOSPACE,
518 &sk->sk_socket->flags);
519 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
520
521 /* Race breaker. If space is freed after
522 * wspace test but before the flags are set,
523 * IO signal will be lost. Memory barrier
524 * pairs with the input side.
525 */
526 smp_mb__after_atomic();
527 if (sk_stream_is_writeable(sk))
528 mask |= POLLOUT | POLLWRNORM;
529 }
530 } else
531 mask |= POLLOUT | POLLWRNORM;
532
533 if (tp->urg_data & TCP_URG_VALID)
534 mask |= POLLPRI;
535 }
536 /* This barrier is coupled with smp_wmb() in tcp_reset() */
537 smp_rmb();
538 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
539 mask |= POLLERR;
540
541 return mask;
542 }
543 EXPORT_SYMBOL(tcp_poll);
544
545 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
546 {
547 struct tcp_sock *tp = tcp_sk(sk);
548 int answ;
549 bool slow;
550
551 switch (cmd) {
552 case SIOCINQ:
553 if (sk->sk_state == TCP_LISTEN)
554 return -EINVAL;
555
556 slow = lock_sock_fast(sk);
557 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
558 answ = 0;
559 else if (sock_flag(sk, SOCK_URGINLINE) ||
560 !tp->urg_data ||
561 before(tp->urg_seq, tp->copied_seq) ||
562 !before(tp->urg_seq, tp->rcv_nxt)) {
563
564 answ = tp->rcv_nxt - tp->copied_seq;
565
566 /* Subtract 1, if FIN was received */
567 if (answ && sock_flag(sk, SOCK_DONE))
568 answ--;
569 } else
570 answ = tp->urg_seq - tp->copied_seq;
571 unlock_sock_fast(sk, slow);
572 break;
573 case SIOCATMARK:
574 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
575 break;
576 case SIOCOUTQ:
577 if (sk->sk_state == TCP_LISTEN)
578 return -EINVAL;
579
580 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
581 answ = 0;
582 else
583 answ = tp->write_seq - tp->snd_una;
584 break;
585 case SIOCOUTQNSD:
586 if (sk->sk_state == TCP_LISTEN)
587 return -EINVAL;
588
589 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
590 answ = 0;
591 else
592 answ = tp->write_seq - tp->snd_nxt;
593 break;
594 default:
595 return -ENOIOCTLCMD;
596 }
597
598 return put_user(answ, (int __user *)arg);
599 }
600 EXPORT_SYMBOL(tcp_ioctl);
601
602 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
603 {
604 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
605 tp->pushed_seq = tp->write_seq;
606 }
607
608 static inline bool forced_push(const struct tcp_sock *tp)
609 {
610 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
611 }
612
613 static void skb_entail(struct sock *sk, struct sk_buff *skb)
614 {
615 struct tcp_sock *tp = tcp_sk(sk);
616 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
617
618 skb->csum = 0;
619 tcb->seq = tcb->end_seq = tp->write_seq;
620 tcb->tcp_flags = TCPHDR_ACK;
621 tcb->sacked = 0;
622 __skb_header_release(skb);
623 tcp_add_write_queue_tail(sk, skb);
624 sk->sk_wmem_queued += skb->truesize;
625 sk_mem_charge(sk, skb->truesize);
626 if (tp->nonagle & TCP_NAGLE_PUSH)
627 tp->nonagle &= ~TCP_NAGLE_PUSH;
628 }
629
630 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
631 {
632 if (flags & MSG_OOB)
633 tp->snd_up = tp->write_seq;
634 }
635
636 /* If a not yet filled skb is pushed, do not send it if
637 * we have data packets in Qdisc or NIC queues :
638 * Because TX completion will happen shortly, it gives a chance
639 * to coalesce future sendmsg() payload into this skb, without
640 * need for a timer, and with no latency trade off.
641 * As packets containing data payload have a bigger truesize
642 * than pure acks (dataless) packets, the last checks prevent
643 * autocorking if we only have an ACK in Qdisc/NIC queues,
644 * or if TX completion was delayed after we processed ACK packet.
645 */
646 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
647 int size_goal)
648 {
649 return skb->len < size_goal &&
650 sysctl_tcp_autocorking &&
651 skb != tcp_write_queue_head(sk) &&
652 atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
653 }
654
655 static void tcp_push(struct sock *sk, int flags, int mss_now,
656 int nonagle, int size_goal)
657 {
658 struct tcp_sock *tp = tcp_sk(sk);
659 struct sk_buff *skb;
660
661 if (!tcp_send_head(sk))
662 return;
663
664 skb = tcp_write_queue_tail(sk);
665 if (!(flags & MSG_MORE) || forced_push(tp))
666 tcp_mark_push(tp, skb);
667
668 tcp_mark_urg(tp, flags);
669
670 if (tcp_should_autocork(sk, skb, size_goal)) {
671
672 /* avoid atomic op if TSQ_THROTTLED bit is already set */
673 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
674 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
675 set_bit(TSQ_THROTTLED, &tp->tsq_flags);
676 }
677 /* It is possible TX completion already happened
678 * before we set TSQ_THROTTLED.
679 */
680 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
681 return;
682 }
683
684 if (flags & MSG_MORE)
685 nonagle = TCP_NAGLE_CORK;
686
687 __tcp_push_pending_frames(sk, mss_now, nonagle);
688 }
689
690 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
691 unsigned int offset, size_t len)
692 {
693 struct tcp_splice_state *tss = rd_desc->arg.data;
694 int ret;
695
696 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
697 tss->flags);
698 if (ret > 0)
699 rd_desc->count -= ret;
700 return ret;
701 }
702
703 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
704 {
705 /* Store TCP splice context information in read_descriptor_t. */
706 read_descriptor_t rd_desc = {
707 .arg.data = tss,
708 .count = tss->len,
709 };
710
711 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
712 }
713
714 /**
715 * tcp_splice_read - splice data from TCP socket to a pipe
716 * @sock: socket to splice from
717 * @ppos: position (not valid)
718 * @pipe: pipe to splice to
719 * @len: number of bytes to splice
720 * @flags: splice modifier flags
721 *
722 * Description:
723 * Will read pages from given socket and fill them into a pipe.
724 *
725 **/
726 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
727 struct pipe_inode_info *pipe, size_t len,
728 unsigned int flags)
729 {
730 struct sock *sk = sock->sk;
731 struct tcp_splice_state tss = {
732 .pipe = pipe,
733 .len = len,
734 .flags = flags,
735 };
736 long timeo;
737 ssize_t spliced;
738 int ret;
739
740 sock_rps_record_flow(sk);
741 /*
742 * We can't seek on a socket input
743 */
744 if (unlikely(*ppos))
745 return -ESPIPE;
746
747 ret = spliced = 0;
748
749 lock_sock(sk);
750
751 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
752 while (tss.len) {
753 ret = __tcp_splice_read(sk, &tss);
754 if (ret < 0)
755 break;
756 else if (!ret) {
757 if (spliced)
758 break;
759 if (sock_flag(sk, SOCK_DONE))
760 break;
761 if (sk->sk_err) {
762 ret = sock_error(sk);
763 break;
764 }
765 if (sk->sk_shutdown & RCV_SHUTDOWN)
766 break;
767 if (sk->sk_state == TCP_CLOSE) {
768 /*
769 * This occurs when user tries to read
770 * from never connected socket.
771 */
772 if (!sock_flag(sk, SOCK_DONE))
773 ret = -ENOTCONN;
774 break;
775 }
776 if (!timeo) {
777 ret = -EAGAIN;
778 break;
779 }
780 sk_wait_data(sk, &timeo);
781 if (signal_pending(current)) {
782 ret = sock_intr_errno(timeo);
783 break;
784 }
785 continue;
786 }
787 tss.len -= ret;
788 spliced += ret;
789
790 if (!timeo)
791 break;
792 release_sock(sk);
793 lock_sock(sk);
794
795 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
796 (sk->sk_shutdown & RCV_SHUTDOWN) ||
797 signal_pending(current))
798 break;
799 }
800
801 release_sock(sk);
802
803 if (spliced)
804 return spliced;
805
806 return ret;
807 }
808 EXPORT_SYMBOL(tcp_splice_read);
809
810 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
811 {
812 struct sk_buff *skb;
813
814 /* The TCP header must be at least 32-bit aligned. */
815 size = ALIGN(size, 4);
816
817 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
818 if (skb) {
819 if (sk_wmem_schedule(sk, skb->truesize)) {
820 skb_reserve(skb, sk->sk_prot->max_header);
821 /*
822 * Make sure that we have exactly size bytes
823 * available to the caller, no more, no less.
824 */
825 skb->reserved_tailroom = skb->end - skb->tail - size;
826 return skb;
827 }
828 __kfree_skb(skb);
829 } else {
830 sk->sk_prot->enter_memory_pressure(sk);
831 sk_stream_moderate_sndbuf(sk);
832 }
833 return NULL;
834 }
835
836 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
837 int large_allowed)
838 {
839 struct tcp_sock *tp = tcp_sk(sk);
840 u32 new_size_goal, size_goal;
841
842 if (!large_allowed || !sk_can_gso(sk))
843 return mss_now;
844
845 /* Note : tcp_tso_autosize() will eventually split this later */
846 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
847 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
848
849 /* We try hard to avoid divides here */
850 size_goal = tp->gso_segs * mss_now;
851 if (unlikely(new_size_goal < size_goal ||
852 new_size_goal >= size_goal + mss_now)) {
853 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
854 sk->sk_gso_max_segs);
855 size_goal = tp->gso_segs * mss_now;
856 }
857
858 return max(size_goal, mss_now);
859 }
860
861 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
862 {
863 int mss_now;
864
865 mss_now = tcp_current_mss(sk);
866 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
867
868 return mss_now;
869 }
870
871 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
872 size_t size, int flags)
873 {
874 struct tcp_sock *tp = tcp_sk(sk);
875 int mss_now, size_goal;
876 int err;
877 ssize_t copied;
878 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
879
880 /* Wait for a connection to finish. One exception is TCP Fast Open
881 * (passive side) where data is allowed to be sent before a connection
882 * is fully established.
883 */
884 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
885 !tcp_passive_fastopen(sk)) {
886 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
887 goto out_err;
888 }
889
890 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
891
892 mss_now = tcp_send_mss(sk, &size_goal, flags);
893 copied = 0;
894
895 err = -EPIPE;
896 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
897 goto out_err;
898
899 while (size > 0) {
900 struct sk_buff *skb = tcp_write_queue_tail(sk);
901 int copy, i;
902 bool can_coalesce;
903
904 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
905 new_segment:
906 if (!sk_stream_memory_free(sk))
907 goto wait_for_sndbuf;
908
909 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
910 if (!skb)
911 goto wait_for_memory;
912
913 skb_entail(sk, skb);
914 copy = size_goal;
915 }
916
917 if (copy > size)
918 copy = size;
919
920 i = skb_shinfo(skb)->nr_frags;
921 can_coalesce = skb_can_coalesce(skb, i, page, offset);
922 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
923 tcp_mark_push(tp, skb);
924 goto new_segment;
925 }
926 if (!sk_wmem_schedule(sk, copy))
927 goto wait_for_memory;
928
929 if (can_coalesce) {
930 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
931 } else {
932 get_page(page);
933 skb_fill_page_desc(skb, i, page, offset, copy);
934 }
935 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
936
937 skb->len += copy;
938 skb->data_len += copy;
939 skb->truesize += copy;
940 sk->sk_wmem_queued += copy;
941 sk_mem_charge(sk, copy);
942 skb->ip_summed = CHECKSUM_PARTIAL;
943 tp->write_seq += copy;
944 TCP_SKB_CB(skb)->end_seq += copy;
945 tcp_skb_pcount_set(skb, 0);
946
947 if (!copied)
948 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
949
950 copied += copy;
951 offset += copy;
952 if (!(size -= copy)) {
953 tcp_tx_timestamp(sk, skb);
954 goto out;
955 }
956
957 if (skb->len < size_goal || (flags & MSG_OOB))
958 continue;
959
960 if (forced_push(tp)) {
961 tcp_mark_push(tp, skb);
962 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
963 } else if (skb == tcp_send_head(sk))
964 tcp_push_one(sk, mss_now);
965 continue;
966
967 wait_for_sndbuf:
968 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
969 wait_for_memory:
970 tcp_push(sk, flags & ~MSG_MORE, mss_now,
971 TCP_NAGLE_PUSH, size_goal);
972
973 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
974 goto do_error;
975
976 mss_now = tcp_send_mss(sk, &size_goal, flags);
977 }
978
979 out:
980 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
981 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
982 return copied;
983
984 do_error:
985 if (copied)
986 goto out;
987 out_err:
988 return sk_stream_error(sk, flags, err);
989 }
990
991 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
992 size_t size, int flags)
993 {
994 ssize_t res;
995
996 if (!(sk->sk_route_caps & NETIF_F_SG) ||
997 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
998 return sock_no_sendpage(sk->sk_socket, page, offset, size,
999 flags);
1000
1001 lock_sock(sk);
1002 res = do_tcp_sendpages(sk, page, offset, size, flags);
1003 release_sock(sk);
1004 return res;
1005 }
1006 EXPORT_SYMBOL(tcp_sendpage);
1007
1008 static inline int select_size(const struct sock *sk, bool sg)
1009 {
1010 const struct tcp_sock *tp = tcp_sk(sk);
1011 int tmp = tp->mss_cache;
1012
1013 if (sg) {
1014 if (sk_can_gso(sk)) {
1015 /* Small frames wont use a full page:
1016 * Payload will immediately follow tcp header.
1017 */
1018 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1019 } else {
1020 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1021
1022 if (tmp >= pgbreak &&
1023 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1024 tmp = pgbreak;
1025 }
1026 }
1027
1028 return tmp;
1029 }
1030
1031 void tcp_free_fastopen_req(struct tcp_sock *tp)
1032 {
1033 if (tp->fastopen_req) {
1034 kfree(tp->fastopen_req);
1035 tp->fastopen_req = NULL;
1036 }
1037 }
1038
1039 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1040 int *copied, size_t size)
1041 {
1042 struct tcp_sock *tp = tcp_sk(sk);
1043 int err, flags;
1044
1045 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1046 return -EOPNOTSUPP;
1047 if (tp->fastopen_req)
1048 return -EALREADY; /* Another Fast Open is in progress */
1049
1050 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1051 sk->sk_allocation);
1052 if (unlikely(!tp->fastopen_req))
1053 return -ENOBUFS;
1054 tp->fastopen_req->data = msg;
1055 tp->fastopen_req->size = size;
1056
1057 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1058 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1059 msg->msg_namelen, flags);
1060 *copied = tp->fastopen_req->copied;
1061 tcp_free_fastopen_req(tp);
1062 return err;
1063 }
1064
1065 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1066 {
1067 struct tcp_sock *tp = tcp_sk(sk);
1068 struct sk_buff *skb;
1069 int flags, err, copied = 0;
1070 int mss_now = 0, size_goal, copied_syn = 0;
1071 bool sg;
1072 long timeo;
1073
1074 lock_sock(sk);
1075
1076 flags = msg->msg_flags;
1077 if (flags & MSG_FASTOPEN) {
1078 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1079 if (err == -EINPROGRESS && copied_syn > 0)
1080 goto out;
1081 else if (err)
1082 goto out_err;
1083 }
1084
1085 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1086
1087 /* Wait for a connection to finish. One exception is TCP Fast Open
1088 * (passive side) where data is allowed to be sent before a connection
1089 * is fully established.
1090 */
1091 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1092 !tcp_passive_fastopen(sk)) {
1093 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1094 goto do_error;
1095 }
1096
1097 if (unlikely(tp->repair)) {
1098 if (tp->repair_queue == TCP_RECV_QUEUE) {
1099 copied = tcp_send_rcvq(sk, msg, size);
1100 goto out_nopush;
1101 }
1102
1103 err = -EINVAL;
1104 if (tp->repair_queue == TCP_NO_QUEUE)
1105 goto out_err;
1106
1107 /* 'common' sending to sendq */
1108 }
1109
1110 /* This should be in poll */
1111 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1112
1113 mss_now = tcp_send_mss(sk, &size_goal, flags);
1114
1115 /* Ok commence sending. */
1116 copied = 0;
1117
1118 err = -EPIPE;
1119 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1120 goto out_err;
1121
1122 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1123
1124 while (msg_data_left(msg)) {
1125 int copy = 0;
1126 int max = size_goal;
1127
1128 skb = tcp_write_queue_tail(sk);
1129 if (tcp_send_head(sk)) {
1130 if (skb->ip_summed == CHECKSUM_NONE)
1131 max = mss_now;
1132 copy = max - skb->len;
1133 }
1134
1135 if (copy <= 0) {
1136 new_segment:
1137 /* Allocate new segment. If the interface is SG,
1138 * allocate skb fitting to single page.
1139 */
1140 if (!sk_stream_memory_free(sk))
1141 goto wait_for_sndbuf;
1142
1143 skb = sk_stream_alloc_skb(sk,
1144 select_size(sk, sg),
1145 sk->sk_allocation);
1146 if (!skb)
1147 goto wait_for_memory;
1148
1149 /*
1150 * Check whether we can use HW checksum.
1151 */
1152 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1153 skb->ip_summed = CHECKSUM_PARTIAL;
1154
1155 skb_entail(sk, skb);
1156 copy = size_goal;
1157 max = size_goal;
1158
1159 /* All packets are restored as if they have
1160 * already been sent. skb_mstamp isn't set to
1161 * avoid wrong rtt estimation.
1162 */
1163 if (tp->repair)
1164 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1165 }
1166
1167 /* Try to append data to the end of skb. */
1168 if (copy > msg_data_left(msg))
1169 copy = msg_data_left(msg);
1170
1171 /* Where to copy to? */
1172 if (skb_availroom(skb) > 0) {
1173 /* We have some space in skb head. Superb! */
1174 copy = min_t(int, copy, skb_availroom(skb));
1175 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1176 if (err)
1177 goto do_fault;
1178 } else {
1179 bool merge = true;
1180 int i = skb_shinfo(skb)->nr_frags;
1181 struct page_frag *pfrag = sk_page_frag(sk);
1182
1183 if (!sk_page_frag_refill(sk, pfrag))
1184 goto wait_for_memory;
1185
1186 if (!skb_can_coalesce(skb, i, pfrag->page,
1187 pfrag->offset)) {
1188 if (i == MAX_SKB_FRAGS || !sg) {
1189 tcp_mark_push(tp, skb);
1190 goto new_segment;
1191 }
1192 merge = false;
1193 }
1194
1195 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1196
1197 if (!sk_wmem_schedule(sk, copy))
1198 goto wait_for_memory;
1199
1200 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1201 pfrag->page,
1202 pfrag->offset,
1203 copy);
1204 if (err)
1205 goto do_error;
1206
1207 /* Update the skb. */
1208 if (merge) {
1209 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1210 } else {
1211 skb_fill_page_desc(skb, i, pfrag->page,
1212 pfrag->offset, copy);
1213 get_page(pfrag->page);
1214 }
1215 pfrag->offset += copy;
1216 }
1217
1218 if (!copied)
1219 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1220
1221 tp->write_seq += copy;
1222 TCP_SKB_CB(skb)->end_seq += copy;
1223 tcp_skb_pcount_set(skb, 0);
1224
1225 copied += copy;
1226 if (!msg_data_left(msg)) {
1227 tcp_tx_timestamp(sk, skb);
1228 goto out;
1229 }
1230
1231 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1232 continue;
1233
1234 if (forced_push(tp)) {
1235 tcp_mark_push(tp, skb);
1236 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1237 } else if (skb == tcp_send_head(sk))
1238 tcp_push_one(sk, mss_now);
1239 continue;
1240
1241 wait_for_sndbuf:
1242 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1243 wait_for_memory:
1244 if (copied)
1245 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1246 TCP_NAGLE_PUSH, size_goal);
1247
1248 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1249 goto do_error;
1250
1251 mss_now = tcp_send_mss(sk, &size_goal, flags);
1252 }
1253
1254 out:
1255 if (copied)
1256 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1257 out_nopush:
1258 release_sock(sk);
1259 return copied + copied_syn;
1260
1261 do_fault:
1262 if (!skb->len) {
1263 tcp_unlink_write_queue(skb, sk);
1264 /* It is the one place in all of TCP, except connection
1265 * reset, where we can be unlinking the send_head.
1266 */
1267 tcp_check_send_head(sk, skb);
1268 sk_wmem_free_skb(sk, skb);
1269 }
1270
1271 do_error:
1272 if (copied + copied_syn)
1273 goto out;
1274 out_err:
1275 err = sk_stream_error(sk, flags, err);
1276 release_sock(sk);
1277 return err;
1278 }
1279 EXPORT_SYMBOL(tcp_sendmsg);
1280
1281 /*
1282 * Handle reading urgent data. BSD has very simple semantics for
1283 * this, no blocking and very strange errors 8)
1284 */
1285
1286 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1287 {
1288 struct tcp_sock *tp = tcp_sk(sk);
1289
1290 /* No URG data to read. */
1291 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1292 tp->urg_data == TCP_URG_READ)
1293 return -EINVAL; /* Yes this is right ! */
1294
1295 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1296 return -ENOTCONN;
1297
1298 if (tp->urg_data & TCP_URG_VALID) {
1299 int err = 0;
1300 char c = tp->urg_data;
1301
1302 if (!(flags & MSG_PEEK))
1303 tp->urg_data = TCP_URG_READ;
1304
1305 /* Read urgent data. */
1306 msg->msg_flags |= MSG_OOB;
1307
1308 if (len > 0) {
1309 if (!(flags & MSG_TRUNC))
1310 err = memcpy_to_msg(msg, &c, 1);
1311 len = 1;
1312 } else
1313 msg->msg_flags |= MSG_TRUNC;
1314
1315 return err ? -EFAULT : len;
1316 }
1317
1318 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1319 return 0;
1320
1321 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1322 * the available implementations agree in this case:
1323 * this call should never block, independent of the
1324 * blocking state of the socket.
1325 * Mike <pall@rz.uni-karlsruhe.de>
1326 */
1327 return -EAGAIN;
1328 }
1329
1330 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1331 {
1332 struct sk_buff *skb;
1333 int copied = 0, err = 0;
1334
1335 /* XXX -- need to support SO_PEEK_OFF */
1336
1337 skb_queue_walk(&sk->sk_write_queue, skb) {
1338 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1339 if (err)
1340 break;
1341
1342 copied += skb->len;
1343 }
1344
1345 return err ?: copied;
1346 }
1347
1348 /* Clean up the receive buffer for full frames taken by the user,
1349 * then send an ACK if necessary. COPIED is the number of bytes
1350 * tcp_recvmsg has given to the user so far, it speeds up the
1351 * calculation of whether or not we must ACK for the sake of
1352 * a window update.
1353 */
1354 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1355 {
1356 struct tcp_sock *tp = tcp_sk(sk);
1357 bool time_to_ack = false;
1358
1359 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1360
1361 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1362 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1363 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1364
1365 if (inet_csk_ack_scheduled(sk)) {
1366 const struct inet_connection_sock *icsk = inet_csk(sk);
1367 /* Delayed ACKs frequently hit locked sockets during bulk
1368 * receive. */
1369 if (icsk->icsk_ack.blocked ||
1370 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1371 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1372 /*
1373 * If this read emptied read buffer, we send ACK, if
1374 * connection is not bidirectional, user drained
1375 * receive buffer and there was a small segment
1376 * in queue.
1377 */
1378 (copied > 0 &&
1379 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1380 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1381 !icsk->icsk_ack.pingpong)) &&
1382 !atomic_read(&sk->sk_rmem_alloc)))
1383 time_to_ack = true;
1384 }
1385
1386 /* We send an ACK if we can now advertise a non-zero window
1387 * which has been raised "significantly".
1388 *
1389 * Even if window raised up to infinity, do not send window open ACK
1390 * in states, where we will not receive more. It is useless.
1391 */
1392 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1393 __u32 rcv_window_now = tcp_receive_window(tp);
1394
1395 /* Optimize, __tcp_select_window() is not cheap. */
1396 if (2*rcv_window_now <= tp->window_clamp) {
1397 __u32 new_window = __tcp_select_window(sk);
1398
1399 /* Send ACK now, if this read freed lots of space
1400 * in our buffer. Certainly, new_window is new window.
1401 * We can advertise it now, if it is not less than current one.
1402 * "Lots" means "at least twice" here.
1403 */
1404 if (new_window && new_window >= 2 * rcv_window_now)
1405 time_to_ack = true;
1406 }
1407 }
1408 if (time_to_ack)
1409 tcp_send_ack(sk);
1410 }
1411
1412 static void tcp_prequeue_process(struct sock *sk)
1413 {
1414 struct sk_buff *skb;
1415 struct tcp_sock *tp = tcp_sk(sk);
1416
1417 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1418
1419 /* RX process wants to run with disabled BHs, though it is not
1420 * necessary */
1421 local_bh_disable();
1422 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1423 sk_backlog_rcv(sk, skb);
1424 local_bh_enable();
1425
1426 /* Clear memory counter. */
1427 tp->ucopy.memory = 0;
1428 }
1429
1430 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1431 {
1432 struct sk_buff *skb;
1433 u32 offset;
1434
1435 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1436 offset = seq - TCP_SKB_CB(skb)->seq;
1437 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1438 offset--;
1439 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1440 *off = offset;
1441 return skb;
1442 }
1443 /* This looks weird, but this can happen if TCP collapsing
1444 * splitted a fat GRO packet, while we released socket lock
1445 * in skb_splice_bits()
1446 */
1447 sk_eat_skb(sk, skb);
1448 }
1449 return NULL;
1450 }
1451
1452 /*
1453 * This routine provides an alternative to tcp_recvmsg() for routines
1454 * that would like to handle copying from skbuffs directly in 'sendfile'
1455 * fashion.
1456 * Note:
1457 * - It is assumed that the socket was locked by the caller.
1458 * - The routine does not block.
1459 * - At present, there is no support for reading OOB data
1460 * or for 'peeking' the socket using this routine
1461 * (although both would be easy to implement).
1462 */
1463 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1464 sk_read_actor_t recv_actor)
1465 {
1466 struct sk_buff *skb;
1467 struct tcp_sock *tp = tcp_sk(sk);
1468 u32 seq = tp->copied_seq;
1469 u32 offset;
1470 int copied = 0;
1471
1472 if (sk->sk_state == TCP_LISTEN)
1473 return -ENOTCONN;
1474 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1475 if (offset < skb->len) {
1476 int used;
1477 size_t len;
1478
1479 len = skb->len - offset;
1480 /* Stop reading if we hit a patch of urgent data */
1481 if (tp->urg_data) {
1482 u32 urg_offset = tp->urg_seq - seq;
1483 if (urg_offset < len)
1484 len = urg_offset;
1485 if (!len)
1486 break;
1487 }
1488 used = recv_actor(desc, skb, offset, len);
1489 if (used <= 0) {
1490 if (!copied)
1491 copied = used;
1492 break;
1493 } else if (used <= len) {
1494 seq += used;
1495 copied += used;
1496 offset += used;
1497 }
1498 /* If recv_actor drops the lock (e.g. TCP splice
1499 * receive) the skb pointer might be invalid when
1500 * getting here: tcp_collapse might have deleted it
1501 * while aggregating skbs from the socket queue.
1502 */
1503 skb = tcp_recv_skb(sk, seq - 1, &offset);
1504 if (!skb)
1505 break;
1506 /* TCP coalescing might have appended data to the skb.
1507 * Try to splice more frags
1508 */
1509 if (offset + 1 != skb->len)
1510 continue;
1511 }
1512 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1513 sk_eat_skb(sk, skb);
1514 ++seq;
1515 break;
1516 }
1517 sk_eat_skb(sk, skb);
1518 if (!desc->count)
1519 break;
1520 tp->copied_seq = seq;
1521 }
1522 tp->copied_seq = seq;
1523
1524 tcp_rcv_space_adjust(sk);
1525
1526 /* Clean up data we have read: This will do ACK frames. */
1527 if (copied > 0) {
1528 tcp_recv_skb(sk, seq, &offset);
1529 tcp_cleanup_rbuf(sk, copied);
1530 }
1531 return copied;
1532 }
1533 EXPORT_SYMBOL(tcp_read_sock);
1534
1535 /*
1536 * This routine copies from a sock struct into the user buffer.
1537 *
1538 * Technical note: in 2.3 we work on _locked_ socket, so that
1539 * tricks with *seq access order and skb->users are not required.
1540 * Probably, code can be easily improved even more.
1541 */
1542
1543 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
1544 int flags, int *addr_len)
1545 {
1546 struct tcp_sock *tp = tcp_sk(sk);
1547 int copied = 0;
1548 u32 peek_seq;
1549 u32 *seq;
1550 unsigned long used;
1551 int err;
1552 int target; /* Read at least this many bytes */
1553 long timeo;
1554 struct task_struct *user_recv = NULL;
1555 struct sk_buff *skb;
1556 u32 urg_hole = 0;
1557
1558 if (unlikely(flags & MSG_ERRQUEUE))
1559 return inet_recv_error(sk, msg, len, addr_len);
1560
1561 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1562 (sk->sk_state == TCP_ESTABLISHED))
1563 sk_busy_loop(sk, nonblock);
1564
1565 lock_sock(sk);
1566
1567 err = -ENOTCONN;
1568 if (sk->sk_state == TCP_LISTEN)
1569 goto out;
1570
1571 timeo = sock_rcvtimeo(sk, nonblock);
1572
1573 /* Urgent data needs to be handled specially. */
1574 if (flags & MSG_OOB)
1575 goto recv_urg;
1576
1577 if (unlikely(tp->repair)) {
1578 err = -EPERM;
1579 if (!(flags & MSG_PEEK))
1580 goto out;
1581
1582 if (tp->repair_queue == TCP_SEND_QUEUE)
1583 goto recv_sndq;
1584
1585 err = -EINVAL;
1586 if (tp->repair_queue == TCP_NO_QUEUE)
1587 goto out;
1588
1589 /* 'common' recv queue MSG_PEEK-ing */
1590 }
1591
1592 seq = &tp->copied_seq;
1593 if (flags & MSG_PEEK) {
1594 peek_seq = tp->copied_seq;
1595 seq = &peek_seq;
1596 }
1597
1598 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1599
1600 do {
1601 u32 offset;
1602
1603 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1604 if (tp->urg_data && tp->urg_seq == *seq) {
1605 if (copied)
1606 break;
1607 if (signal_pending(current)) {
1608 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1609 break;
1610 }
1611 }
1612
1613 /* Next get a buffer. */
1614
1615 skb_queue_walk(&sk->sk_receive_queue, skb) {
1616 /* Now that we have two receive queues this
1617 * shouldn't happen.
1618 */
1619 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1620 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1621 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1622 flags))
1623 break;
1624
1625 offset = *seq - TCP_SKB_CB(skb)->seq;
1626 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1627 offset--;
1628 if (offset < skb->len)
1629 goto found_ok_skb;
1630 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1631 goto found_fin_ok;
1632 WARN(!(flags & MSG_PEEK),
1633 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1634 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1635 }
1636
1637 /* Well, if we have backlog, try to process it now yet. */
1638
1639 if (copied >= target && !sk->sk_backlog.tail)
1640 break;
1641
1642 if (copied) {
1643 if (sk->sk_err ||
1644 sk->sk_state == TCP_CLOSE ||
1645 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1646 !timeo ||
1647 signal_pending(current))
1648 break;
1649 } else {
1650 if (sock_flag(sk, SOCK_DONE))
1651 break;
1652
1653 if (sk->sk_err) {
1654 copied = sock_error(sk);
1655 break;
1656 }
1657
1658 if (sk->sk_shutdown & RCV_SHUTDOWN)
1659 break;
1660
1661 if (sk->sk_state == TCP_CLOSE) {
1662 if (!sock_flag(sk, SOCK_DONE)) {
1663 /* This occurs when user tries to read
1664 * from never connected socket.
1665 */
1666 copied = -ENOTCONN;
1667 break;
1668 }
1669 break;
1670 }
1671
1672 if (!timeo) {
1673 copied = -EAGAIN;
1674 break;
1675 }
1676
1677 if (signal_pending(current)) {
1678 copied = sock_intr_errno(timeo);
1679 break;
1680 }
1681 }
1682
1683 tcp_cleanup_rbuf(sk, copied);
1684
1685 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1686 /* Install new reader */
1687 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1688 user_recv = current;
1689 tp->ucopy.task = user_recv;
1690 tp->ucopy.msg = msg;
1691 }
1692
1693 tp->ucopy.len = len;
1694
1695 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1696 !(flags & (MSG_PEEK | MSG_TRUNC)));
1697
1698 /* Ugly... If prequeue is not empty, we have to
1699 * process it before releasing socket, otherwise
1700 * order will be broken at second iteration.
1701 * More elegant solution is required!!!
1702 *
1703 * Look: we have the following (pseudo)queues:
1704 *
1705 * 1. packets in flight
1706 * 2. backlog
1707 * 3. prequeue
1708 * 4. receive_queue
1709 *
1710 * Each queue can be processed only if the next ones
1711 * are empty. At this point we have empty receive_queue.
1712 * But prequeue _can_ be not empty after 2nd iteration,
1713 * when we jumped to start of loop because backlog
1714 * processing added something to receive_queue.
1715 * We cannot release_sock(), because backlog contains
1716 * packets arrived _after_ prequeued ones.
1717 *
1718 * Shortly, algorithm is clear --- to process all
1719 * the queues in order. We could make it more directly,
1720 * requeueing packets from backlog to prequeue, if
1721 * is not empty. It is more elegant, but eats cycles,
1722 * unfortunately.
1723 */
1724 if (!skb_queue_empty(&tp->ucopy.prequeue))
1725 goto do_prequeue;
1726
1727 /* __ Set realtime policy in scheduler __ */
1728 }
1729
1730 if (copied >= target) {
1731 /* Do not sleep, just process backlog. */
1732 release_sock(sk);
1733 lock_sock(sk);
1734 } else
1735 sk_wait_data(sk, &timeo);
1736
1737 if (user_recv) {
1738 int chunk;
1739
1740 /* __ Restore normal policy in scheduler __ */
1741
1742 if ((chunk = len - tp->ucopy.len) != 0) {
1743 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1744 len -= chunk;
1745 copied += chunk;
1746 }
1747
1748 if (tp->rcv_nxt == tp->copied_seq &&
1749 !skb_queue_empty(&tp->ucopy.prequeue)) {
1750 do_prequeue:
1751 tcp_prequeue_process(sk);
1752
1753 if ((chunk = len - tp->ucopy.len) != 0) {
1754 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1755 len -= chunk;
1756 copied += chunk;
1757 }
1758 }
1759 }
1760 if ((flags & MSG_PEEK) &&
1761 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1762 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1763 current->comm,
1764 task_pid_nr(current));
1765 peek_seq = tp->copied_seq;
1766 }
1767 continue;
1768
1769 found_ok_skb:
1770 /* Ok so how much can we use? */
1771 used = skb->len - offset;
1772 if (len < used)
1773 used = len;
1774
1775 /* Do we have urgent data here? */
1776 if (tp->urg_data) {
1777 u32 urg_offset = tp->urg_seq - *seq;
1778 if (urg_offset < used) {
1779 if (!urg_offset) {
1780 if (!sock_flag(sk, SOCK_URGINLINE)) {
1781 ++*seq;
1782 urg_hole++;
1783 offset++;
1784 used--;
1785 if (!used)
1786 goto skip_copy;
1787 }
1788 } else
1789 used = urg_offset;
1790 }
1791 }
1792
1793 if (!(flags & MSG_TRUNC)) {
1794 err = skb_copy_datagram_msg(skb, offset, msg, used);
1795 if (err) {
1796 /* Exception. Bailout! */
1797 if (!copied)
1798 copied = -EFAULT;
1799 break;
1800 }
1801 }
1802
1803 *seq += used;
1804 copied += used;
1805 len -= used;
1806
1807 tcp_rcv_space_adjust(sk);
1808
1809 skip_copy:
1810 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1811 tp->urg_data = 0;
1812 tcp_fast_path_check(sk);
1813 }
1814 if (used + offset < skb->len)
1815 continue;
1816
1817 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1818 goto found_fin_ok;
1819 if (!(flags & MSG_PEEK))
1820 sk_eat_skb(sk, skb);
1821 continue;
1822
1823 found_fin_ok:
1824 /* Process the FIN. */
1825 ++*seq;
1826 if (!(flags & MSG_PEEK))
1827 sk_eat_skb(sk, skb);
1828 break;
1829 } while (len > 0);
1830
1831 if (user_recv) {
1832 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1833 int chunk;
1834
1835 tp->ucopy.len = copied > 0 ? len : 0;
1836
1837 tcp_prequeue_process(sk);
1838
1839 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1840 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1841 len -= chunk;
1842 copied += chunk;
1843 }
1844 }
1845
1846 tp->ucopy.task = NULL;
1847 tp->ucopy.len = 0;
1848 }
1849
1850 /* According to UNIX98, msg_name/msg_namelen are ignored
1851 * on connected socket. I was just happy when found this 8) --ANK
1852 */
1853
1854 /* Clean up data we have read: This will do ACK frames. */
1855 tcp_cleanup_rbuf(sk, copied);
1856
1857 release_sock(sk);
1858 return copied;
1859
1860 out:
1861 release_sock(sk);
1862 return err;
1863
1864 recv_urg:
1865 err = tcp_recv_urg(sk, msg, len, flags);
1866 goto out;
1867
1868 recv_sndq:
1869 err = tcp_peek_sndq(sk, msg, len);
1870 goto out;
1871 }
1872 EXPORT_SYMBOL(tcp_recvmsg);
1873
1874 void tcp_set_state(struct sock *sk, int state)
1875 {
1876 int oldstate = sk->sk_state;
1877
1878 switch (state) {
1879 case TCP_ESTABLISHED:
1880 if (oldstate != TCP_ESTABLISHED)
1881 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1882 break;
1883
1884 case TCP_CLOSE:
1885 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1886 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1887
1888 sk->sk_prot->unhash(sk);
1889 if (inet_csk(sk)->icsk_bind_hash &&
1890 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1891 inet_put_port(sk);
1892 /* fall through */
1893 default:
1894 if (oldstate == TCP_ESTABLISHED)
1895 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1896 }
1897
1898 /* Change state AFTER socket is unhashed to avoid closed
1899 * socket sitting in hash tables.
1900 */
1901 sk->sk_state = state;
1902
1903 #ifdef STATE_TRACE
1904 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1905 #endif
1906 }
1907 EXPORT_SYMBOL_GPL(tcp_set_state);
1908
1909 /*
1910 * State processing on a close. This implements the state shift for
1911 * sending our FIN frame. Note that we only send a FIN for some
1912 * states. A shutdown() may have already sent the FIN, or we may be
1913 * closed.
1914 */
1915
1916 static const unsigned char new_state[16] = {
1917 /* current state: new state: action: */
1918 [0 /* (Invalid) */] = TCP_CLOSE,
1919 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1920 [TCP_SYN_SENT] = TCP_CLOSE,
1921 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1922 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
1923 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
1924 [TCP_TIME_WAIT] = TCP_CLOSE,
1925 [TCP_CLOSE] = TCP_CLOSE,
1926 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
1927 [TCP_LAST_ACK] = TCP_LAST_ACK,
1928 [TCP_LISTEN] = TCP_CLOSE,
1929 [TCP_CLOSING] = TCP_CLOSING,
1930 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
1931 };
1932
1933 static int tcp_close_state(struct sock *sk)
1934 {
1935 int next = (int)new_state[sk->sk_state];
1936 int ns = next & TCP_STATE_MASK;
1937
1938 tcp_set_state(sk, ns);
1939
1940 return next & TCP_ACTION_FIN;
1941 }
1942
1943 /*
1944 * Shutdown the sending side of a connection. Much like close except
1945 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1946 */
1947
1948 void tcp_shutdown(struct sock *sk, int how)
1949 {
1950 /* We need to grab some memory, and put together a FIN,
1951 * and then put it into the queue to be sent.
1952 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1953 */
1954 if (!(how & SEND_SHUTDOWN))
1955 return;
1956
1957 /* If we've already sent a FIN, or it's a closed state, skip this. */
1958 if ((1 << sk->sk_state) &
1959 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1960 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1961 /* Clear out any half completed packets. FIN if needed. */
1962 if (tcp_close_state(sk))
1963 tcp_send_fin(sk);
1964 }
1965 }
1966 EXPORT_SYMBOL(tcp_shutdown);
1967
1968 bool tcp_check_oom(struct sock *sk, int shift)
1969 {
1970 bool too_many_orphans, out_of_socket_memory;
1971
1972 too_many_orphans = tcp_too_many_orphans(sk, shift);
1973 out_of_socket_memory = tcp_out_of_memory(sk);
1974
1975 if (too_many_orphans)
1976 net_info_ratelimited("too many orphaned sockets\n");
1977 if (out_of_socket_memory)
1978 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
1979 return too_many_orphans || out_of_socket_memory;
1980 }
1981
1982 void tcp_close(struct sock *sk, long timeout)
1983 {
1984 struct sk_buff *skb;
1985 int data_was_unread = 0;
1986 int state;
1987
1988 lock_sock(sk);
1989 sk->sk_shutdown = SHUTDOWN_MASK;
1990
1991 if (sk->sk_state == TCP_LISTEN) {
1992 tcp_set_state(sk, TCP_CLOSE);
1993
1994 /* Special case. */
1995 inet_csk_listen_stop(sk);
1996
1997 goto adjudge_to_death;
1998 }
1999
2000 /* We need to flush the recv. buffs. We do this only on the
2001 * descriptor close, not protocol-sourced closes, because the
2002 * reader process may not have drained the data yet!
2003 */
2004 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2005 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2006
2007 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2008 len--;
2009 data_was_unread += len;
2010 __kfree_skb(skb);
2011 }
2012
2013 sk_mem_reclaim(sk);
2014
2015 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2016 if (sk->sk_state == TCP_CLOSE)
2017 goto adjudge_to_death;
2018
2019 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2020 * data was lost. To witness the awful effects of the old behavior of
2021 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2022 * GET in an FTP client, suspend the process, wait for the client to
2023 * advertise a zero window, then kill -9 the FTP client, wheee...
2024 * Note: timeout is always zero in such a case.
2025 */
2026 if (unlikely(tcp_sk(sk)->repair)) {
2027 sk->sk_prot->disconnect(sk, 0);
2028 } else if (data_was_unread) {
2029 /* Unread data was tossed, zap the connection. */
2030 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2031 tcp_set_state(sk, TCP_CLOSE);
2032 tcp_send_active_reset(sk, sk->sk_allocation);
2033 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2034 /* Check zero linger _after_ checking for unread data. */
2035 sk->sk_prot->disconnect(sk, 0);
2036 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2037 } else if (tcp_close_state(sk)) {
2038 /* We FIN if the application ate all the data before
2039 * zapping the connection.
2040 */
2041
2042 /* RED-PEN. Formally speaking, we have broken TCP state
2043 * machine. State transitions:
2044 *
2045 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2046 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2047 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2048 *
2049 * are legal only when FIN has been sent (i.e. in window),
2050 * rather than queued out of window. Purists blame.
2051 *
2052 * F.e. "RFC state" is ESTABLISHED,
2053 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2054 *
2055 * The visible declinations are that sometimes
2056 * we enter time-wait state, when it is not required really
2057 * (harmless), do not send active resets, when they are
2058 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2059 * they look as CLOSING or LAST_ACK for Linux)
2060 * Probably, I missed some more holelets.
2061 * --ANK
2062 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2063 * in a single packet! (May consider it later but will
2064 * probably need API support or TCP_CORK SYN-ACK until
2065 * data is written and socket is closed.)
2066 */
2067 tcp_send_fin(sk);
2068 }
2069
2070 sk_stream_wait_close(sk, timeout);
2071
2072 adjudge_to_death:
2073 state = sk->sk_state;
2074 sock_hold(sk);
2075 sock_orphan(sk);
2076
2077 /* It is the last release_sock in its life. It will remove backlog. */
2078 release_sock(sk);
2079
2080
2081 /* Now socket is owned by kernel and we acquire BH lock
2082 to finish close. No need to check for user refs.
2083 */
2084 local_bh_disable();
2085 bh_lock_sock(sk);
2086 WARN_ON(sock_owned_by_user(sk));
2087
2088 percpu_counter_inc(sk->sk_prot->orphan_count);
2089
2090 /* Have we already been destroyed by a softirq or backlog? */
2091 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2092 goto out;
2093
2094 /* This is a (useful) BSD violating of the RFC. There is a
2095 * problem with TCP as specified in that the other end could
2096 * keep a socket open forever with no application left this end.
2097 * We use a 1 minute timeout (about the same as BSD) then kill
2098 * our end. If they send after that then tough - BUT: long enough
2099 * that we won't make the old 4*rto = almost no time - whoops
2100 * reset mistake.
2101 *
2102 * Nope, it was not mistake. It is really desired behaviour
2103 * f.e. on http servers, when such sockets are useless, but
2104 * consume significant resources. Let's do it with special
2105 * linger2 option. --ANK
2106 */
2107
2108 if (sk->sk_state == TCP_FIN_WAIT2) {
2109 struct tcp_sock *tp = tcp_sk(sk);
2110 if (tp->linger2 < 0) {
2111 tcp_set_state(sk, TCP_CLOSE);
2112 tcp_send_active_reset(sk, GFP_ATOMIC);
2113 NET_INC_STATS_BH(sock_net(sk),
2114 LINUX_MIB_TCPABORTONLINGER);
2115 } else {
2116 const int tmo = tcp_fin_time(sk);
2117
2118 if (tmo > TCP_TIMEWAIT_LEN) {
2119 inet_csk_reset_keepalive_timer(sk,
2120 tmo - TCP_TIMEWAIT_LEN);
2121 } else {
2122 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2123 goto out;
2124 }
2125 }
2126 }
2127 if (sk->sk_state != TCP_CLOSE) {
2128 sk_mem_reclaim(sk);
2129 if (tcp_check_oom(sk, 0)) {
2130 tcp_set_state(sk, TCP_CLOSE);
2131 tcp_send_active_reset(sk, GFP_ATOMIC);
2132 NET_INC_STATS_BH(sock_net(sk),
2133 LINUX_MIB_TCPABORTONMEMORY);
2134 }
2135 }
2136
2137 if (sk->sk_state == TCP_CLOSE) {
2138 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2139 /* We could get here with a non-NULL req if the socket is
2140 * aborted (e.g., closed with unread data) before 3WHS
2141 * finishes.
2142 */
2143 if (req)
2144 reqsk_fastopen_remove(sk, req, false);
2145 inet_csk_destroy_sock(sk);
2146 }
2147 /* Otherwise, socket is reprieved until protocol close. */
2148
2149 out:
2150 bh_unlock_sock(sk);
2151 local_bh_enable();
2152 sock_put(sk);
2153 }
2154 EXPORT_SYMBOL(tcp_close);
2155
2156 /* These states need RST on ABORT according to RFC793 */
2157
2158 static inline bool tcp_need_reset(int state)
2159 {
2160 return (1 << state) &
2161 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2162 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2163 }
2164
2165 int tcp_disconnect(struct sock *sk, int flags)
2166 {
2167 struct inet_sock *inet = inet_sk(sk);
2168 struct inet_connection_sock *icsk = inet_csk(sk);
2169 struct tcp_sock *tp = tcp_sk(sk);
2170 int err = 0;
2171 int old_state = sk->sk_state;
2172
2173 if (old_state != TCP_CLOSE)
2174 tcp_set_state(sk, TCP_CLOSE);
2175
2176 /* ABORT function of RFC793 */
2177 if (old_state == TCP_LISTEN) {
2178 inet_csk_listen_stop(sk);
2179 } else if (unlikely(tp->repair)) {
2180 sk->sk_err = ECONNABORTED;
2181 } else if (tcp_need_reset(old_state) ||
2182 (tp->snd_nxt != tp->write_seq &&
2183 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2184 /* The last check adjusts for discrepancy of Linux wrt. RFC
2185 * states
2186 */
2187 tcp_send_active_reset(sk, gfp_any());
2188 sk->sk_err = ECONNRESET;
2189 } else if (old_state == TCP_SYN_SENT)
2190 sk->sk_err = ECONNRESET;
2191
2192 tcp_clear_xmit_timers(sk);
2193 __skb_queue_purge(&sk->sk_receive_queue);
2194 tcp_write_queue_purge(sk);
2195 __skb_queue_purge(&tp->out_of_order_queue);
2196
2197 inet->inet_dport = 0;
2198
2199 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2200 inet_reset_saddr(sk);
2201
2202 sk->sk_shutdown = 0;
2203 sock_reset_flag(sk, SOCK_DONE);
2204 tp->srtt_us = 0;
2205 if ((tp->write_seq += tp->max_window + 2) == 0)
2206 tp->write_seq = 1;
2207 icsk->icsk_backoff = 0;
2208 tp->snd_cwnd = 2;
2209 icsk->icsk_probes_out = 0;
2210 tp->packets_out = 0;
2211 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2212 tp->snd_cwnd_cnt = 0;
2213 tp->window_clamp = 0;
2214 tcp_set_ca_state(sk, TCP_CA_Open);
2215 tcp_clear_retrans(tp);
2216 inet_csk_delack_init(sk);
2217 tcp_init_send_head(sk);
2218 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2219 __sk_dst_reset(sk);
2220
2221 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2222
2223 sk->sk_error_report(sk);
2224 return err;
2225 }
2226 EXPORT_SYMBOL(tcp_disconnect);
2227
2228 void tcp_sock_destruct(struct sock *sk)
2229 {
2230 inet_sock_destruct(sk);
2231
2232 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2233 }
2234
2235 static inline bool tcp_can_repair_sock(const struct sock *sk)
2236 {
2237 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2238 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2239 }
2240
2241 static int tcp_repair_options_est(struct tcp_sock *tp,
2242 struct tcp_repair_opt __user *optbuf, unsigned int len)
2243 {
2244 struct tcp_repair_opt opt;
2245
2246 while (len >= sizeof(opt)) {
2247 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2248 return -EFAULT;
2249
2250 optbuf++;
2251 len -= sizeof(opt);
2252
2253 switch (opt.opt_code) {
2254 case TCPOPT_MSS:
2255 tp->rx_opt.mss_clamp = opt.opt_val;
2256 break;
2257 case TCPOPT_WINDOW:
2258 {
2259 u16 snd_wscale = opt.opt_val & 0xFFFF;
2260 u16 rcv_wscale = opt.opt_val >> 16;
2261
2262 if (snd_wscale > 14 || rcv_wscale > 14)
2263 return -EFBIG;
2264
2265 tp->rx_opt.snd_wscale = snd_wscale;
2266 tp->rx_opt.rcv_wscale = rcv_wscale;
2267 tp->rx_opt.wscale_ok = 1;
2268 }
2269 break;
2270 case TCPOPT_SACK_PERM:
2271 if (opt.opt_val != 0)
2272 return -EINVAL;
2273
2274 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2275 if (sysctl_tcp_fack)
2276 tcp_enable_fack(tp);
2277 break;
2278 case TCPOPT_TIMESTAMP:
2279 if (opt.opt_val != 0)
2280 return -EINVAL;
2281
2282 tp->rx_opt.tstamp_ok = 1;
2283 break;
2284 }
2285 }
2286
2287 return 0;
2288 }
2289
2290 /*
2291 * Socket option code for TCP.
2292 */
2293 static int do_tcp_setsockopt(struct sock *sk, int level,
2294 int optname, char __user *optval, unsigned int optlen)
2295 {
2296 struct tcp_sock *tp = tcp_sk(sk);
2297 struct inet_connection_sock *icsk = inet_csk(sk);
2298 int val;
2299 int err = 0;
2300
2301 /* These are data/string values, all the others are ints */
2302 switch (optname) {
2303 case TCP_CONGESTION: {
2304 char name[TCP_CA_NAME_MAX];
2305
2306 if (optlen < 1)
2307 return -EINVAL;
2308
2309 val = strncpy_from_user(name, optval,
2310 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2311 if (val < 0)
2312 return -EFAULT;
2313 name[val] = 0;
2314
2315 lock_sock(sk);
2316 err = tcp_set_congestion_control(sk, name);
2317 release_sock(sk);
2318 return err;
2319 }
2320 default:
2321 /* fallthru */
2322 break;
2323 }
2324
2325 if (optlen < sizeof(int))
2326 return -EINVAL;
2327
2328 if (get_user(val, (int __user *)optval))
2329 return -EFAULT;
2330
2331 lock_sock(sk);
2332
2333 switch (optname) {
2334 case TCP_MAXSEG:
2335 /* Values greater than interface MTU won't take effect. However
2336 * at the point when this call is done we typically don't yet
2337 * know which interface is going to be used */
2338 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2339 err = -EINVAL;
2340 break;
2341 }
2342 tp->rx_opt.user_mss = val;
2343 break;
2344
2345 case TCP_NODELAY:
2346 if (val) {
2347 /* TCP_NODELAY is weaker than TCP_CORK, so that
2348 * this option on corked socket is remembered, but
2349 * it is not activated until cork is cleared.
2350 *
2351 * However, when TCP_NODELAY is set we make
2352 * an explicit push, which overrides even TCP_CORK
2353 * for currently queued segments.
2354 */
2355 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2356 tcp_push_pending_frames(sk);
2357 } else {
2358 tp->nonagle &= ~TCP_NAGLE_OFF;
2359 }
2360 break;
2361
2362 case TCP_THIN_LINEAR_TIMEOUTS:
2363 if (val < 0 || val > 1)
2364 err = -EINVAL;
2365 else
2366 tp->thin_lto = val;
2367 break;
2368
2369 case TCP_THIN_DUPACK:
2370 if (val < 0 || val > 1)
2371 err = -EINVAL;
2372 else {
2373 tp->thin_dupack = val;
2374 if (tp->thin_dupack)
2375 tcp_disable_early_retrans(tp);
2376 }
2377 break;
2378
2379 case TCP_REPAIR:
2380 if (!tcp_can_repair_sock(sk))
2381 err = -EPERM;
2382 else if (val == 1) {
2383 tp->repair = 1;
2384 sk->sk_reuse = SK_FORCE_REUSE;
2385 tp->repair_queue = TCP_NO_QUEUE;
2386 } else if (val == 0) {
2387 tp->repair = 0;
2388 sk->sk_reuse = SK_NO_REUSE;
2389 tcp_send_window_probe(sk);
2390 } else
2391 err = -EINVAL;
2392
2393 break;
2394
2395 case TCP_REPAIR_QUEUE:
2396 if (!tp->repair)
2397 err = -EPERM;
2398 else if (val < TCP_QUEUES_NR)
2399 tp->repair_queue = val;
2400 else
2401 err = -EINVAL;
2402 break;
2403
2404 case TCP_QUEUE_SEQ:
2405 if (sk->sk_state != TCP_CLOSE)
2406 err = -EPERM;
2407 else if (tp->repair_queue == TCP_SEND_QUEUE)
2408 tp->write_seq = val;
2409 else if (tp->repair_queue == TCP_RECV_QUEUE)
2410 tp->rcv_nxt = val;
2411 else
2412 err = -EINVAL;
2413 break;
2414
2415 case TCP_REPAIR_OPTIONS:
2416 if (!tp->repair)
2417 err = -EINVAL;
2418 else if (sk->sk_state == TCP_ESTABLISHED)
2419 err = tcp_repair_options_est(tp,
2420 (struct tcp_repair_opt __user *)optval,
2421 optlen);
2422 else
2423 err = -EPERM;
2424 break;
2425
2426 case TCP_CORK:
2427 /* When set indicates to always queue non-full frames.
2428 * Later the user clears this option and we transmit
2429 * any pending partial frames in the queue. This is
2430 * meant to be used alongside sendfile() to get properly
2431 * filled frames when the user (for example) must write
2432 * out headers with a write() call first and then use
2433 * sendfile to send out the data parts.
2434 *
2435 * TCP_CORK can be set together with TCP_NODELAY and it is
2436 * stronger than TCP_NODELAY.
2437 */
2438 if (val) {
2439 tp->nonagle |= TCP_NAGLE_CORK;
2440 } else {
2441 tp->nonagle &= ~TCP_NAGLE_CORK;
2442 if (tp->nonagle&TCP_NAGLE_OFF)
2443 tp->nonagle |= TCP_NAGLE_PUSH;
2444 tcp_push_pending_frames(sk);
2445 }
2446 break;
2447
2448 case TCP_KEEPIDLE:
2449 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2450 err = -EINVAL;
2451 else {
2452 tp->keepalive_time = val * HZ;
2453 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2454 !((1 << sk->sk_state) &
2455 (TCPF_CLOSE | TCPF_LISTEN))) {
2456 u32 elapsed = keepalive_time_elapsed(tp);
2457 if (tp->keepalive_time > elapsed)
2458 elapsed = tp->keepalive_time - elapsed;
2459 else
2460 elapsed = 0;
2461 inet_csk_reset_keepalive_timer(sk, elapsed);
2462 }
2463 }
2464 break;
2465 case TCP_KEEPINTVL:
2466 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2467 err = -EINVAL;
2468 else
2469 tp->keepalive_intvl = val * HZ;
2470 break;
2471 case TCP_KEEPCNT:
2472 if (val < 1 || val > MAX_TCP_KEEPCNT)
2473 err = -EINVAL;
2474 else
2475 tp->keepalive_probes = val;
2476 break;
2477 case TCP_SYNCNT:
2478 if (val < 1 || val > MAX_TCP_SYNCNT)
2479 err = -EINVAL;
2480 else
2481 icsk->icsk_syn_retries = val;
2482 break;
2483
2484 case TCP_LINGER2:
2485 if (val < 0)
2486 tp->linger2 = -1;
2487 else if (val > sysctl_tcp_fin_timeout / HZ)
2488 tp->linger2 = 0;
2489 else
2490 tp->linger2 = val * HZ;
2491 break;
2492
2493 case TCP_DEFER_ACCEPT:
2494 /* Translate value in seconds to number of retransmits */
2495 icsk->icsk_accept_queue.rskq_defer_accept =
2496 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2497 TCP_RTO_MAX / HZ);
2498 break;
2499
2500 case TCP_WINDOW_CLAMP:
2501 if (!val) {
2502 if (sk->sk_state != TCP_CLOSE) {
2503 err = -EINVAL;
2504 break;
2505 }
2506 tp->window_clamp = 0;
2507 } else
2508 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2509 SOCK_MIN_RCVBUF / 2 : val;
2510 break;
2511
2512 case TCP_QUICKACK:
2513 if (!val) {
2514 icsk->icsk_ack.pingpong = 1;
2515 } else {
2516 icsk->icsk_ack.pingpong = 0;
2517 if ((1 << sk->sk_state) &
2518 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2519 inet_csk_ack_scheduled(sk)) {
2520 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2521 tcp_cleanup_rbuf(sk, 1);
2522 if (!(val & 1))
2523 icsk->icsk_ack.pingpong = 1;
2524 }
2525 }
2526 break;
2527
2528 #ifdef CONFIG_TCP_MD5SIG
2529 case TCP_MD5SIG:
2530 /* Read the IP->Key mappings from userspace */
2531 err = tp->af_specific->md5_parse(sk, optval, optlen);
2532 break;
2533 #endif
2534 case TCP_USER_TIMEOUT:
2535 /* Cap the max time in ms TCP will retry or probe the window
2536 * before giving up and aborting (ETIMEDOUT) a connection.
2537 */
2538 if (val < 0)
2539 err = -EINVAL;
2540 else
2541 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2542 break;
2543
2544 case TCP_FASTOPEN:
2545 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2546 TCPF_LISTEN)))
2547 err = fastopen_init_queue(sk, val);
2548 else
2549 err = -EINVAL;
2550 break;
2551 case TCP_TIMESTAMP:
2552 if (!tp->repair)
2553 err = -EPERM;
2554 else
2555 tp->tsoffset = val - tcp_time_stamp;
2556 break;
2557 case TCP_NOTSENT_LOWAT:
2558 tp->notsent_lowat = val;
2559 sk->sk_write_space(sk);
2560 break;
2561 default:
2562 err = -ENOPROTOOPT;
2563 break;
2564 }
2565
2566 release_sock(sk);
2567 return err;
2568 }
2569
2570 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2571 unsigned int optlen)
2572 {
2573 const struct inet_connection_sock *icsk = inet_csk(sk);
2574
2575 if (level != SOL_TCP)
2576 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2577 optval, optlen);
2578 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2579 }
2580 EXPORT_SYMBOL(tcp_setsockopt);
2581
2582 #ifdef CONFIG_COMPAT
2583 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2584 char __user *optval, unsigned int optlen)
2585 {
2586 if (level != SOL_TCP)
2587 return inet_csk_compat_setsockopt(sk, level, optname,
2588 optval, optlen);
2589 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2590 }
2591 EXPORT_SYMBOL(compat_tcp_setsockopt);
2592 #endif
2593
2594 /* Return information about state of tcp endpoint in API format. */
2595 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2596 {
2597 const struct tcp_sock *tp = tcp_sk(sk);
2598 const struct inet_connection_sock *icsk = inet_csk(sk);
2599 u32 now = tcp_time_stamp;
2600 u32 rate;
2601
2602 memset(info, 0, sizeof(*info));
2603
2604 info->tcpi_state = sk->sk_state;
2605 info->tcpi_ca_state = icsk->icsk_ca_state;
2606 info->tcpi_retransmits = icsk->icsk_retransmits;
2607 info->tcpi_probes = icsk->icsk_probes_out;
2608 info->tcpi_backoff = icsk->icsk_backoff;
2609
2610 if (tp->rx_opt.tstamp_ok)
2611 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2612 if (tcp_is_sack(tp))
2613 info->tcpi_options |= TCPI_OPT_SACK;
2614 if (tp->rx_opt.wscale_ok) {
2615 info->tcpi_options |= TCPI_OPT_WSCALE;
2616 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2617 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2618 }
2619
2620 if (tp->ecn_flags & TCP_ECN_OK)
2621 info->tcpi_options |= TCPI_OPT_ECN;
2622 if (tp->ecn_flags & TCP_ECN_SEEN)
2623 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2624 if (tp->syn_data_acked)
2625 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2626
2627 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2628 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2629 info->tcpi_snd_mss = tp->mss_cache;
2630 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2631
2632 if (sk->sk_state == TCP_LISTEN) {
2633 info->tcpi_unacked = sk->sk_ack_backlog;
2634 info->tcpi_sacked = sk->sk_max_ack_backlog;
2635 } else {
2636 info->tcpi_unacked = tp->packets_out;
2637 info->tcpi_sacked = tp->sacked_out;
2638 }
2639 info->tcpi_lost = tp->lost_out;
2640 info->tcpi_retrans = tp->retrans_out;
2641 info->tcpi_fackets = tp->fackets_out;
2642
2643 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2644 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2645 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2646
2647 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2648 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2649 info->tcpi_rtt = tp->srtt_us >> 3;
2650 info->tcpi_rttvar = tp->mdev_us >> 2;
2651 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2652 info->tcpi_snd_cwnd = tp->snd_cwnd;
2653 info->tcpi_advmss = tp->advmss;
2654 info->tcpi_reordering = tp->reordering;
2655
2656 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2657 info->tcpi_rcv_space = tp->rcvq_space.space;
2658
2659 info->tcpi_total_retrans = tp->total_retrans;
2660
2661 rate = READ_ONCE(sk->sk_pacing_rate);
2662 info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;
2663
2664 rate = READ_ONCE(sk->sk_max_pacing_rate);
2665 info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
2666
2667 spin_lock_bh(&sk->sk_lock.slock);
2668 info->tcpi_bytes_acked = tp->bytes_acked;
2669 info->tcpi_bytes_received = tp->bytes_received;
2670 spin_unlock_bh(&sk->sk_lock.slock);
2671 }
2672 EXPORT_SYMBOL_GPL(tcp_get_info);
2673
2674 static int do_tcp_getsockopt(struct sock *sk, int level,
2675 int optname, char __user *optval, int __user *optlen)
2676 {
2677 struct inet_connection_sock *icsk = inet_csk(sk);
2678 struct tcp_sock *tp = tcp_sk(sk);
2679 int val, len;
2680
2681 if (get_user(len, optlen))
2682 return -EFAULT;
2683
2684 len = min_t(unsigned int, len, sizeof(int));
2685
2686 if (len < 0)
2687 return -EINVAL;
2688
2689 switch (optname) {
2690 case TCP_MAXSEG:
2691 val = tp->mss_cache;
2692 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2693 val = tp->rx_opt.user_mss;
2694 if (tp->repair)
2695 val = tp->rx_opt.mss_clamp;
2696 break;
2697 case TCP_NODELAY:
2698 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2699 break;
2700 case TCP_CORK:
2701 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2702 break;
2703 case TCP_KEEPIDLE:
2704 val = keepalive_time_when(tp) / HZ;
2705 break;
2706 case TCP_KEEPINTVL:
2707 val = keepalive_intvl_when(tp) / HZ;
2708 break;
2709 case TCP_KEEPCNT:
2710 val = keepalive_probes(tp);
2711 break;
2712 case TCP_SYNCNT:
2713 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2714 break;
2715 case TCP_LINGER2:
2716 val = tp->linger2;
2717 if (val >= 0)
2718 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2719 break;
2720 case TCP_DEFER_ACCEPT:
2721 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2722 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2723 break;
2724 case TCP_WINDOW_CLAMP:
2725 val = tp->window_clamp;
2726 break;
2727 case TCP_INFO: {
2728 struct tcp_info info;
2729
2730 if (get_user(len, optlen))
2731 return -EFAULT;
2732
2733 tcp_get_info(sk, &info);
2734
2735 len = min_t(unsigned int, len, sizeof(info));
2736 if (put_user(len, optlen))
2737 return -EFAULT;
2738 if (copy_to_user(optval, &info, len))
2739 return -EFAULT;
2740 return 0;
2741 }
2742 case TCP_QUICKACK:
2743 val = !icsk->icsk_ack.pingpong;
2744 break;
2745
2746 case TCP_CONGESTION:
2747 if (get_user(len, optlen))
2748 return -EFAULT;
2749 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2750 if (put_user(len, optlen))
2751 return -EFAULT;
2752 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2753 return -EFAULT;
2754 return 0;
2755
2756 case TCP_THIN_LINEAR_TIMEOUTS:
2757 val = tp->thin_lto;
2758 break;
2759 case TCP_THIN_DUPACK:
2760 val = tp->thin_dupack;
2761 break;
2762
2763 case TCP_REPAIR:
2764 val = tp->repair;
2765 break;
2766
2767 case TCP_REPAIR_QUEUE:
2768 if (tp->repair)
2769 val = tp->repair_queue;
2770 else
2771 return -EINVAL;
2772 break;
2773
2774 case TCP_QUEUE_SEQ:
2775 if (tp->repair_queue == TCP_SEND_QUEUE)
2776 val = tp->write_seq;
2777 else if (tp->repair_queue == TCP_RECV_QUEUE)
2778 val = tp->rcv_nxt;
2779 else
2780 return -EINVAL;
2781 break;
2782
2783 case TCP_USER_TIMEOUT:
2784 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2785 break;
2786
2787 case TCP_FASTOPEN:
2788 if (icsk->icsk_accept_queue.fastopenq)
2789 val = icsk->icsk_accept_queue.fastopenq->max_qlen;
2790 else
2791 val = 0;
2792 break;
2793
2794 case TCP_TIMESTAMP:
2795 val = tcp_time_stamp + tp->tsoffset;
2796 break;
2797 case TCP_NOTSENT_LOWAT:
2798 val = tp->notsent_lowat;
2799 break;
2800 default:
2801 return -ENOPROTOOPT;
2802 }
2803
2804 if (put_user(len, optlen))
2805 return -EFAULT;
2806 if (copy_to_user(optval, &val, len))
2807 return -EFAULT;
2808 return 0;
2809 }
2810
2811 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2812 int __user *optlen)
2813 {
2814 struct inet_connection_sock *icsk = inet_csk(sk);
2815
2816 if (level != SOL_TCP)
2817 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2818 optval, optlen);
2819 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2820 }
2821 EXPORT_SYMBOL(tcp_getsockopt);
2822
2823 #ifdef CONFIG_COMPAT
2824 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2825 char __user *optval, int __user *optlen)
2826 {
2827 if (level != SOL_TCP)
2828 return inet_csk_compat_getsockopt(sk, level, optname,
2829 optval, optlen);
2830 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2831 }
2832 EXPORT_SYMBOL(compat_tcp_getsockopt);
2833 #endif
2834
2835 #ifdef CONFIG_TCP_MD5SIG
2836 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2837 static DEFINE_MUTEX(tcp_md5sig_mutex);
2838 static bool tcp_md5sig_pool_populated = false;
2839
2840 static void __tcp_alloc_md5sig_pool(void)
2841 {
2842 int cpu;
2843
2844 for_each_possible_cpu(cpu) {
2845 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
2846 struct crypto_hash *hash;
2847
2848 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2849 if (IS_ERR_OR_NULL(hash))
2850 return;
2851 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
2852 }
2853 }
2854 /* before setting tcp_md5sig_pool_populated, we must commit all writes
2855 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2856 */
2857 smp_wmb();
2858 tcp_md5sig_pool_populated = true;
2859 }
2860
2861 bool tcp_alloc_md5sig_pool(void)
2862 {
2863 if (unlikely(!tcp_md5sig_pool_populated)) {
2864 mutex_lock(&tcp_md5sig_mutex);
2865
2866 if (!tcp_md5sig_pool_populated)
2867 __tcp_alloc_md5sig_pool();
2868
2869 mutex_unlock(&tcp_md5sig_mutex);
2870 }
2871 return tcp_md5sig_pool_populated;
2872 }
2873 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2874
2875
2876 /**
2877 * tcp_get_md5sig_pool - get md5sig_pool for this user
2878 *
2879 * We use percpu structure, so if we succeed, we exit with preemption
2880 * and BH disabled, to make sure another thread or softirq handling
2881 * wont try to get same context.
2882 */
2883 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2884 {
2885 local_bh_disable();
2886
2887 if (tcp_md5sig_pool_populated) {
2888 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
2889 smp_rmb();
2890 return this_cpu_ptr(&tcp_md5sig_pool);
2891 }
2892 local_bh_enable();
2893 return NULL;
2894 }
2895 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2896
2897 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2898 const struct tcphdr *th)
2899 {
2900 struct scatterlist sg;
2901 struct tcphdr hdr;
2902 int err;
2903
2904 /* We are not allowed to change tcphdr, make a local copy */
2905 memcpy(&hdr, th, sizeof(hdr));
2906 hdr.check = 0;
2907
2908 /* options aren't included in the hash */
2909 sg_init_one(&sg, &hdr, sizeof(hdr));
2910 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2911 return err;
2912 }
2913 EXPORT_SYMBOL(tcp_md5_hash_header);
2914
2915 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2916 const struct sk_buff *skb, unsigned int header_len)
2917 {
2918 struct scatterlist sg;
2919 const struct tcphdr *tp = tcp_hdr(skb);
2920 struct hash_desc *desc = &hp->md5_desc;
2921 unsigned int i;
2922 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
2923 skb_headlen(skb) - header_len : 0;
2924 const struct skb_shared_info *shi = skb_shinfo(skb);
2925 struct sk_buff *frag_iter;
2926
2927 sg_init_table(&sg, 1);
2928
2929 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2930 if (crypto_hash_update(desc, &sg, head_data_len))
2931 return 1;
2932
2933 for (i = 0; i < shi->nr_frags; ++i) {
2934 const struct skb_frag_struct *f = &shi->frags[i];
2935 unsigned int offset = f->page_offset;
2936 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
2937
2938 sg_set_page(&sg, page, skb_frag_size(f),
2939 offset_in_page(offset));
2940 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2941 return 1;
2942 }
2943
2944 skb_walk_frags(skb, frag_iter)
2945 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
2946 return 1;
2947
2948 return 0;
2949 }
2950 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2951
2952 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
2953 {
2954 struct scatterlist sg;
2955
2956 sg_init_one(&sg, key->key, key->keylen);
2957 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2958 }
2959 EXPORT_SYMBOL(tcp_md5_hash_key);
2960
2961 #endif
2962
2963 void tcp_done(struct sock *sk)
2964 {
2965 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2966
2967 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2968 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2969
2970 tcp_set_state(sk, TCP_CLOSE);
2971 tcp_clear_xmit_timers(sk);
2972 if (req)
2973 reqsk_fastopen_remove(sk, req, false);
2974
2975 sk->sk_shutdown = SHUTDOWN_MASK;
2976
2977 if (!sock_flag(sk, SOCK_DEAD))
2978 sk->sk_state_change(sk);
2979 else
2980 inet_csk_destroy_sock(sk);
2981 }
2982 EXPORT_SYMBOL_GPL(tcp_done);
2983
2984 extern struct tcp_congestion_ops tcp_reno;
2985
2986 static __initdata unsigned long thash_entries;
2987 static int __init set_thash_entries(char *str)
2988 {
2989 ssize_t ret;
2990
2991 if (!str)
2992 return 0;
2993
2994 ret = kstrtoul(str, 0, &thash_entries);
2995 if (ret)
2996 return 0;
2997
2998 return 1;
2999 }
3000 __setup("thash_entries=", set_thash_entries);
3001
3002 static void __init tcp_init_mem(void)
3003 {
3004 unsigned long limit = nr_free_buffer_pages() / 8;
3005 limit = max(limit, 128UL);
3006 sysctl_tcp_mem[0] = limit / 4 * 3;
3007 sysctl_tcp_mem[1] = limit;
3008 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3009 }
3010
3011 void __init tcp_init(void)
3012 {
3013 unsigned long limit;
3014 int max_rshare, max_wshare, cnt;
3015 unsigned int i;
3016
3017 sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
3018
3019 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3020 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3021 tcp_hashinfo.bind_bucket_cachep =
3022 kmem_cache_create("tcp_bind_bucket",
3023 sizeof(struct inet_bind_bucket), 0,
3024 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3025
3026 /* Size and allocate the main established and bind bucket
3027 * hash tables.
3028 *
3029 * The methodology is similar to that of the buffer cache.
3030 */
3031 tcp_hashinfo.ehash =
3032 alloc_large_system_hash("TCP established",
3033 sizeof(struct inet_ehash_bucket),
3034 thash_entries,
3035 17, /* one slot per 128 KB of memory */
3036 0,
3037 NULL,
3038 &tcp_hashinfo.ehash_mask,
3039 0,
3040 thash_entries ? 0 : 512 * 1024);
3041 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3042 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3043
3044 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3045 panic("TCP: failed to alloc ehash_locks");
3046 tcp_hashinfo.bhash =
3047 alloc_large_system_hash("TCP bind",
3048 sizeof(struct inet_bind_hashbucket),
3049 tcp_hashinfo.ehash_mask + 1,
3050 17, /* one slot per 128 KB of memory */
3051 0,
3052 &tcp_hashinfo.bhash_size,
3053 NULL,
3054 0,
3055 64 * 1024);
3056 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3057 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3058 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3059 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3060 }
3061
3062
3063 cnt = tcp_hashinfo.ehash_mask + 1;
3064
3065 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3066 sysctl_tcp_max_orphans = cnt / 2;
3067 sysctl_max_syn_backlog = max(128, cnt / 256);
3068
3069 tcp_init_mem();
3070 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3071 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3072 max_wshare = min(4UL*1024*1024, limit);
3073 max_rshare = min(6UL*1024*1024, limit);
3074
3075 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3076 sysctl_tcp_wmem[1] = 16*1024;
3077 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3078
3079 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3080 sysctl_tcp_rmem[1] = 87380;
3081 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3082
3083 pr_info("Hash tables configured (established %u bind %u)\n",
3084 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3085
3086 tcp_metrics_init();
3087 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
3088 tcp_tasklet_init();
3089 }
Linux kernel - Deliverables
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