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.
6 * Implementation of the Transmission Control Protocol(TCP).
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>
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
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
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
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
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
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
55 * Alan Cox : Tidied tcp_data to avoid a potential
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
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
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
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
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
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
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
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
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
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
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
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
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
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
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
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
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
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.
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.
213 * Description of States:
215 * TCP_SYN_SENT sent a connection request, waiting for ack
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
220 * TCP_ESTABLISHED connection established
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
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)
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)
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
245 * TCP_CLOSE socket is finished
248 #define pr_fmt(fmt) "TCP: " fmt
250 #include <crypto/hash.h>
251 #include <linux/kernel.h>
252 #include <linux/module.h>
253 #include <linux/types.h>
254 #include <linux/fcntl.h>
255 #include <linux/poll.h>
256 #include <linux/inet_diag.h>
257 #include <linux/init.h>
258 #include <linux/fs.h>
259 #include <linux/skbuff.h>
260 #include <linux/scatterlist.h>
261 #include <linux/splice.h>
262 #include <linux/net.h>
263 #include <linux/socket.h>
264 #include <linux/random.h>
265 #include <linux/bootmem.h>
266 #include <linux/highmem.h>
267 #include <linux/swap.h>
268 #include <linux/cache.h>
269 #include <linux/err.h>
270 #include <linux/time.h>
271 #include <linux/slab.h>
272 #include <linux/errqueue.h>
274 #include <net/icmp.h>
275 #include <net/inet_common.h>
277 #include <net/xfrm.h>
279 #include <net/sock.h>
281 #include <linux/uaccess.h>
282 #include <asm/ioctls.h>
283 #include <net/busy_poll.h>
285 int sysctl_tcp_min_tso_segs __read_mostly = 2;
287 int sysctl_tcp_autocorking __read_mostly = 1;
289 struct percpu_counter tcp_orphan_count;
290 EXPORT_SYMBOL_GPL(tcp_orphan_count);
292 long sysctl_tcp_mem[3] __read_mostly;
293 int sysctl_tcp_wmem[3] __read_mostly;
294 int sysctl_tcp_rmem[3] __read_mostly;
296 EXPORT_SYMBOL(sysctl_tcp_mem);
297 EXPORT_SYMBOL(sysctl_tcp_rmem);
298 EXPORT_SYMBOL(sysctl_tcp_wmem);
300 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
301 EXPORT_SYMBOL(tcp_memory_allocated);
304 * Current number of TCP sockets.
306 struct percpu_counter tcp_sockets_allocated;
307 EXPORT_SYMBOL(tcp_sockets_allocated);
312 struct tcp_splice_state {
313 struct pipe_inode_info *pipe;
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.
324 unsigned long tcp_memory_pressure __read_mostly;
325 EXPORT_SYMBOL_GPL(tcp_memory_pressure);
327 void tcp_enter_memory_pressure(struct sock *sk)
331 if (READ_ONCE(tcp_memory_pressure))
337 if (!cmpxchg(&tcp_memory_pressure, 0, val))
338 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
340 EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure);
342 void tcp_leave_memory_pressure(struct sock *sk)
346 if (!READ_ONCE(tcp_memory_pressure))
348 val = xchg(&tcp_memory_pressure, 0);
350 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO,
351 jiffies_to_msecs(jiffies - val));
353 EXPORT_SYMBOL_GPL(tcp_leave_memory_pressure);
355 /* Convert seconds to retransmits based on initial and max timeout */
356 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
361 int period = timeout;
364 while (seconds > period && res < 255) {
367 if (timeout > rto_max)
375 /* Convert retransmits to seconds based on initial and max timeout */
376 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
384 if (timeout > rto_max)
392 static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
394 u32 rate = READ_ONCE(tp->rate_delivered);
395 u32 intv = READ_ONCE(tp->rate_interval_us);
399 rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
400 do_div(rate64, intv);
405 /* Address-family independent initialization for a tcp_sock.
407 * NOTE: A lot of things set to zero explicitly by call to
408 * sk_alloc() so need not be done here.
410 void tcp_init_sock(struct sock *sk)
412 struct inet_connection_sock *icsk = inet_csk(sk);
413 struct tcp_sock *tp = tcp_sk(sk);
415 tp->out_of_order_queue = RB_ROOT;
416 tcp_init_xmit_timers(sk);
417 INIT_LIST_HEAD(&tp->tsq_node);
419 icsk->icsk_rto = TCP_TIMEOUT_INIT;
420 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
421 minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
423 /* So many TCP implementations out there (incorrectly) count the
424 * initial SYN frame in their delayed-ACK and congestion control
425 * algorithms that we must have the following bandaid to talk
426 * efficiently to them. -DaveM
428 tp->snd_cwnd = TCP_INIT_CWND;
430 /* There's a bubble in the pipe until at least the first ACK. */
431 tp->app_limited = ~0U;
433 /* See draft-stevens-tcpca-spec-01 for discussion of the
434 * initialization of these values.
436 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
437 tp->snd_cwnd_clamp = ~0;
438 tp->mss_cache = TCP_MSS_DEFAULT;
440 tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering;
441 tcp_assign_congestion_control(sk);
445 sk->sk_state = TCP_CLOSE;
447 sk->sk_write_space = sk_stream_write_space;
448 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
450 icsk->icsk_sync_mss = tcp_sync_mss;
452 sk->sk_sndbuf = sysctl_tcp_wmem[1];
453 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
455 sk_sockets_allocated_inc(sk);
457 EXPORT_SYMBOL(tcp_init_sock);
459 static void tcp_tx_timestamp(struct sock *sk, u16 tsflags, struct sk_buff *skb)
461 if (tsflags && skb) {
462 struct skb_shared_info *shinfo = skb_shinfo(skb);
463 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
465 sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
466 if (tsflags & SOF_TIMESTAMPING_TX_ACK)
467 tcb->txstamp_ack = 1;
468 if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
469 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
474 * Wait for a TCP event.
476 * Note that we don't need to lock the socket, as the upper poll layers
477 * take care of normal races (between the test and the event) and we don't
478 * go look at any of the socket buffers directly.
480 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
483 struct sock *sk = sock->sk;
484 const struct tcp_sock *tp = tcp_sk(sk);
487 sock_rps_record_flow(sk);
489 sock_poll_wait(file, sk_sleep(sk), wait);
491 state = sk_state_load(sk);
492 if (state == TCP_LISTEN)
493 return inet_csk_listen_poll(sk);
495 /* Socket is not locked. We are protected from async events
496 * by poll logic and correct handling of state changes
497 * made by other threads is impossible in any case.
503 * POLLHUP is certainly not done right. But poll() doesn't
504 * have a notion of HUP in just one direction, and for a
505 * socket the read side is more interesting.
507 * Some poll() documentation says that POLLHUP is incompatible
508 * with the POLLOUT/POLLWR flags, so somebody should check this
509 * all. But careful, it tends to be safer to return too many
510 * bits than too few, and you can easily break real applications
511 * if you don't tell them that something has hung up!
515 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
516 * our fs/select.c). It means that after we received EOF,
517 * poll always returns immediately, making impossible poll() on write()
518 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
519 * if and only if shutdown has been made in both directions.
520 * Actually, it is interesting to look how Solaris and DUX
521 * solve this dilemma. I would prefer, if POLLHUP were maskable,
522 * then we could set it on SND_SHUTDOWN. BTW examples given
523 * in Stevens' books assume exactly this behaviour, it explains
524 * why POLLHUP is incompatible with POLLOUT. --ANK
526 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
527 * blocking on fresh not-connected or disconnected socket. --ANK
529 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
531 if (sk->sk_shutdown & RCV_SHUTDOWN)
532 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
534 /* Connected or passive Fast Open socket? */
535 if (state != TCP_SYN_SENT &&
536 (state != TCP_SYN_RECV || tp->fastopen_rsk)) {
537 int target = sock_rcvlowat(sk, 0, INT_MAX);
539 if (tp->urg_seq == tp->copied_seq &&
540 !sock_flag(sk, SOCK_URGINLINE) &&
544 if (tp->rcv_nxt - tp->copied_seq >= target)
545 mask |= POLLIN | POLLRDNORM;
547 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
548 if (sk_stream_is_writeable(sk)) {
549 mask |= POLLOUT | POLLWRNORM;
550 } else { /* send SIGIO later */
551 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
552 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
554 /* Race breaker. If space is freed after
555 * wspace test but before the flags are set,
556 * IO signal will be lost. Memory barrier
557 * pairs with the input side.
559 smp_mb__after_atomic();
560 if (sk_stream_is_writeable(sk))
561 mask |= POLLOUT | POLLWRNORM;
564 mask |= POLLOUT | POLLWRNORM;
566 if (tp->urg_data & TCP_URG_VALID)
568 } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
569 /* Active TCP fastopen socket with defer_connect
570 * Return POLLOUT so application can call write()
571 * in order for kernel to generate SYN+data
573 mask |= POLLOUT | POLLWRNORM;
575 /* This barrier is coupled with smp_wmb() in tcp_reset() */
577 if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
582 EXPORT_SYMBOL(tcp_poll);
584 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
586 struct tcp_sock *tp = tcp_sk(sk);
592 if (sk->sk_state == TCP_LISTEN)
595 slow = lock_sock_fast(sk);
597 unlock_sock_fast(sk, slow);
600 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
603 if (sk->sk_state == TCP_LISTEN)
606 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
609 answ = tp->write_seq - tp->snd_una;
612 if (sk->sk_state == TCP_LISTEN)
615 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
618 answ = tp->write_seq - tp->snd_nxt;
624 return put_user(answ, (int __user *)arg);
626 EXPORT_SYMBOL(tcp_ioctl);
628 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
630 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
631 tp->pushed_seq = tp->write_seq;
634 static inline bool forced_push(const struct tcp_sock *tp)
636 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
639 static void skb_entail(struct sock *sk, struct sk_buff *skb)
641 struct tcp_sock *tp = tcp_sk(sk);
642 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
645 tcb->seq = tcb->end_seq = tp->write_seq;
646 tcb->tcp_flags = TCPHDR_ACK;
648 __skb_header_release(skb);
649 tcp_add_write_queue_tail(sk, skb);
650 sk->sk_wmem_queued += skb->truesize;
651 sk_mem_charge(sk, skb->truesize);
652 if (tp->nonagle & TCP_NAGLE_PUSH)
653 tp->nonagle &= ~TCP_NAGLE_PUSH;
655 tcp_slow_start_after_idle_check(sk);
658 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
661 tp->snd_up = tp->write_seq;
664 /* If a not yet filled skb is pushed, do not send it if
665 * we have data packets in Qdisc or NIC queues :
666 * Because TX completion will happen shortly, it gives a chance
667 * to coalesce future sendmsg() payload into this skb, without
668 * need for a timer, and with no latency trade off.
669 * As packets containing data payload have a bigger truesize
670 * than pure acks (dataless) packets, the last checks prevent
671 * autocorking if we only have an ACK in Qdisc/NIC queues,
672 * or if TX completion was delayed after we processed ACK packet.
674 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
677 return skb->len < size_goal &&
678 sysctl_tcp_autocorking &&
679 skb != tcp_write_queue_head(sk) &&
680 refcount_read(&sk->sk_wmem_alloc) > skb->truesize;
683 static void tcp_push(struct sock *sk, int flags, int mss_now,
684 int nonagle, int size_goal)
686 struct tcp_sock *tp = tcp_sk(sk);
689 if (!tcp_send_head(sk))
692 skb = tcp_write_queue_tail(sk);
693 if (!(flags & MSG_MORE) || forced_push(tp))
694 tcp_mark_push(tp, skb);
696 tcp_mark_urg(tp, flags);
698 if (tcp_should_autocork(sk, skb, size_goal)) {
700 /* avoid atomic op if TSQ_THROTTLED bit is already set */
701 if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {
702 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
703 set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags);
705 /* It is possible TX completion already happened
706 * before we set TSQ_THROTTLED.
708 if (refcount_read(&sk->sk_wmem_alloc) > skb->truesize)
712 if (flags & MSG_MORE)
713 nonagle = TCP_NAGLE_CORK;
715 __tcp_push_pending_frames(sk, mss_now, nonagle);
718 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
719 unsigned int offset, size_t len)
721 struct tcp_splice_state *tss = rd_desc->arg.data;
724 ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
725 min(rd_desc->count, len), tss->flags);
727 rd_desc->count -= ret;
731 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
733 /* Store TCP splice context information in read_descriptor_t. */
734 read_descriptor_t rd_desc = {
739 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
743 * tcp_splice_read - splice data from TCP socket to a pipe
744 * @sock: socket to splice from
745 * @ppos: position (not valid)
746 * @pipe: pipe to splice to
747 * @len: number of bytes to splice
748 * @flags: splice modifier flags
751 * Will read pages from given socket and fill them into a pipe.
754 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
755 struct pipe_inode_info *pipe, size_t len,
758 struct sock *sk = sock->sk;
759 struct tcp_splice_state tss = {
768 sock_rps_record_flow(sk);
770 * We can't seek on a socket input
779 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
781 ret = __tcp_splice_read(sk, &tss);
787 if (sock_flag(sk, SOCK_DONE))
790 ret = sock_error(sk);
793 if (sk->sk_shutdown & RCV_SHUTDOWN)
795 if (sk->sk_state == TCP_CLOSE) {
797 * This occurs when user tries to read
798 * from never connected socket.
800 if (!sock_flag(sk, SOCK_DONE))
808 /* if __tcp_splice_read() got nothing while we have
809 * an skb in receive queue, we do not want to loop.
810 * This might happen with URG data.
812 if (!skb_queue_empty(&sk->sk_receive_queue))
814 sk_wait_data(sk, &timeo, NULL);
815 if (signal_pending(current)) {
816 ret = sock_intr_errno(timeo);
829 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
830 (sk->sk_shutdown & RCV_SHUTDOWN) ||
831 signal_pending(current))
842 EXPORT_SYMBOL(tcp_splice_read);
844 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
849 /* The TCP header must be at least 32-bit aligned. */
850 size = ALIGN(size, 4);
852 if (unlikely(tcp_under_memory_pressure(sk)))
853 sk_mem_reclaim_partial(sk);
855 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
859 if (force_schedule) {
860 mem_scheduled = true;
861 sk_forced_mem_schedule(sk, skb->truesize);
863 mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
865 if (likely(mem_scheduled)) {
866 skb_reserve(skb, sk->sk_prot->max_header);
868 * Make sure that we have exactly size bytes
869 * available to the caller, no more, no less.
871 skb->reserved_tailroom = skb->end - skb->tail - size;
876 sk->sk_prot->enter_memory_pressure(sk);
877 sk_stream_moderate_sndbuf(sk);
882 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
885 struct tcp_sock *tp = tcp_sk(sk);
886 u32 new_size_goal, size_goal;
888 if (!large_allowed || !sk_can_gso(sk))
891 /* Note : tcp_tso_autosize() will eventually split this later */
892 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
893 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
895 /* We try hard to avoid divides here */
896 size_goal = tp->gso_segs * mss_now;
897 if (unlikely(new_size_goal < size_goal ||
898 new_size_goal >= size_goal + mss_now)) {
899 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
900 sk->sk_gso_max_segs);
901 size_goal = tp->gso_segs * mss_now;
904 return max(size_goal, mss_now);
907 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
911 mss_now = tcp_current_mss(sk);
912 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
917 /* In some cases, both sendpage() and sendmsg() could have added
918 * an skb to the write queue, but failed adding payload on it.
919 * We need to remove it to consume less memory, but more
920 * importantly be able to generate EPOLLOUT for Edge Trigger epoll()
923 static void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)
925 if (skb && !skb->len &&
926 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq) {
927 tcp_unlink_write_queue(skb, sk);
928 tcp_check_send_head(sk, skb);
929 sk_wmem_free_skb(sk, skb);
933 ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
934 size_t size, int flags)
936 struct tcp_sock *tp = tcp_sk(sk);
937 int mss_now, size_goal;
940 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
942 /* Wait for a connection to finish. One exception is TCP Fast Open
943 * (passive side) where data is allowed to be sent before a connection
944 * is fully established.
946 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
947 !tcp_passive_fastopen(sk)) {
948 err = sk_stream_wait_connect(sk, &timeo);
953 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
955 mss_now = tcp_send_mss(sk, &size_goal, flags);
959 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
963 struct sk_buff *skb = tcp_write_queue_tail(sk);
967 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0 ||
968 !tcp_skb_can_collapse_to(skb)) {
970 if (!sk_stream_memory_free(sk))
971 goto wait_for_sndbuf;
973 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
974 skb_queue_empty(&sk->sk_write_queue));
976 goto wait_for_memory;
985 i = skb_shinfo(skb)->nr_frags;
986 can_coalesce = skb_can_coalesce(skb, i, page, offset);
987 if (!can_coalesce && i >= sysctl_max_skb_frags) {
988 tcp_mark_push(tp, skb);
991 if (!sk_wmem_schedule(sk, copy))
992 goto wait_for_memory;
995 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
998 skb_fill_page_desc(skb, i, page, offset, copy);
1000 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1003 skb->data_len += copy;
1004 skb->truesize += copy;
1005 sk->sk_wmem_queued += copy;
1006 sk_mem_charge(sk, copy);
1007 skb->ip_summed = CHECKSUM_PARTIAL;
1008 tp->write_seq += copy;
1009 TCP_SKB_CB(skb)->end_seq += copy;
1010 tcp_skb_pcount_set(skb, 0);
1013 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1021 if (skb->len < size_goal || (flags & MSG_OOB))
1024 if (forced_push(tp)) {
1025 tcp_mark_push(tp, skb);
1026 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1027 } else if (skb == tcp_send_head(sk))
1028 tcp_push_one(sk, mss_now);
1032 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1034 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1035 TCP_NAGLE_PUSH, size_goal);
1037 err = sk_stream_wait_memory(sk, &timeo);
1041 mss_now = tcp_send_mss(sk, &size_goal, flags);
1046 tcp_tx_timestamp(sk, sk->sk_tsflags, tcp_write_queue_tail(sk));
1047 if (!(flags & MSG_SENDPAGE_NOTLAST))
1048 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1053 tcp_remove_empty_skb(sk, tcp_write_queue_tail(sk));
1057 /* make sure we wake any epoll edge trigger waiter */
1058 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
1060 sk->sk_write_space(sk);
1061 tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
1063 return sk_stream_error(sk, flags, err);
1065 EXPORT_SYMBOL_GPL(do_tcp_sendpages);
1067 int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,
1068 size_t size, int flags)
1070 if (!(sk->sk_route_caps & NETIF_F_SG) ||
1071 !sk_check_csum_caps(sk))
1072 return sock_no_sendpage_locked(sk, page, offset, size, flags);
1074 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1076 return do_tcp_sendpages(sk, page, offset, size, flags);
1078 EXPORT_SYMBOL_GPL(tcp_sendpage_locked);
1080 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
1081 size_t size, int flags)
1086 ret = tcp_sendpage_locked(sk, page, offset, size, flags);
1091 EXPORT_SYMBOL(tcp_sendpage);
1093 /* Do not bother using a page frag for very small frames.
1094 * But use this heuristic only for the first skb in write queue.
1096 * Having no payload in skb->head allows better SACK shifting
1097 * in tcp_shift_skb_data(), reducing sack/rack overhead, because
1098 * write queue has less skbs.
1099 * Each skb can hold up to MAX_SKB_FRAGS * 32Kbytes, or ~0.5 MB.
1100 * This also speeds up tso_fragment(), since it wont fallback
1101 * to tcp_fragment().
1103 static int linear_payload_sz(bool first_skb)
1106 return SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1110 static int select_size(const struct sock *sk, bool sg, bool first_skb)
1112 const struct tcp_sock *tp = tcp_sk(sk);
1113 int tmp = tp->mss_cache;
1116 if (sk_can_gso(sk)) {
1117 tmp = linear_payload_sz(first_skb);
1119 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1121 if (tmp >= pgbreak &&
1122 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1130 void tcp_free_fastopen_req(struct tcp_sock *tp)
1132 if (tp->fastopen_req) {
1133 kfree(tp->fastopen_req);
1134 tp->fastopen_req = NULL;
1138 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1139 int *copied, size_t size)
1141 struct tcp_sock *tp = tcp_sk(sk);
1142 struct inet_sock *inet = inet_sk(sk);
1143 struct sockaddr *uaddr = msg->msg_name;
1146 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) ||
1147 (uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
1148 uaddr->sa_family == AF_UNSPEC))
1150 if (tp->fastopen_req)
1151 return -EALREADY; /* Another Fast Open is in progress */
1153 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1155 if (unlikely(!tp->fastopen_req))
1157 tp->fastopen_req->data = msg;
1158 tp->fastopen_req->size = size;
1160 if (inet->defer_connect) {
1161 err = tcp_connect(sk);
1162 /* Same failure procedure as in tcp_v4/6_connect */
1164 tcp_set_state(sk, TCP_CLOSE);
1165 inet->inet_dport = 0;
1166 sk->sk_route_caps = 0;
1169 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1170 err = __inet_stream_connect(sk->sk_socket, uaddr,
1171 msg->msg_namelen, flags, 1);
1172 /* fastopen_req could already be freed in __inet_stream_connect
1173 * if the connection times out or gets rst
1175 if (tp->fastopen_req) {
1176 *copied = tp->fastopen_req->copied;
1177 tcp_free_fastopen_req(tp);
1178 inet->defer_connect = 0;
1183 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
1185 struct tcp_sock *tp = tcp_sk(sk);
1186 struct ubuf_info *uarg = NULL;
1187 struct sk_buff *skb;
1188 struct sockcm_cookie sockc;
1189 int flags, err, copied = 0;
1190 int mss_now = 0, size_goal, copied_syn = 0;
1191 bool process_backlog = false;
1195 flags = msg->msg_flags;
1197 if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) {
1198 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1203 skb = tcp_send_head(sk) ? tcp_write_queue_tail(sk) : NULL;
1204 uarg = sock_zerocopy_realloc(sk, size, skb_zcopy(skb));
1210 if (!(sk_check_csum_caps(sk) && sk->sk_route_caps & NETIF_F_SG))
1214 if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) &&
1216 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1217 if (err == -EINPROGRESS && copied_syn > 0)
1223 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1225 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1227 /* Wait for a connection to finish. One exception is TCP Fast Open
1228 * (passive side) where data is allowed to be sent before a connection
1229 * is fully established.
1231 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1232 !tcp_passive_fastopen(sk)) {
1233 err = sk_stream_wait_connect(sk, &timeo);
1238 if (unlikely(tp->repair)) {
1239 if (tp->repair_queue == TCP_RECV_QUEUE) {
1240 copied = tcp_send_rcvq(sk, msg, size);
1245 if (tp->repair_queue == TCP_NO_QUEUE)
1248 /* 'common' sending to sendq */
1251 sockc.tsflags = sk->sk_tsflags;
1252 if (msg->msg_controllen) {
1253 err = sock_cmsg_send(sk, msg, &sockc);
1254 if (unlikely(err)) {
1260 /* This should be in poll */
1261 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1263 /* Ok commence sending. */
1267 mss_now = tcp_send_mss(sk, &size_goal, flags);
1270 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1273 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1275 while (msg_data_left(msg)) {
1277 int max = size_goal;
1279 skb = tcp_write_queue_tail(sk);
1280 if (tcp_send_head(sk)) {
1281 if (skb->ip_summed == CHECKSUM_NONE)
1283 copy = max - skb->len;
1286 if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
1290 /* Allocate new segment. If the interface is SG,
1291 * allocate skb fitting to single page.
1293 if (!sk_stream_memory_free(sk))
1294 goto wait_for_sndbuf;
1296 if (process_backlog && sk_flush_backlog(sk)) {
1297 process_backlog = false;
1300 first_skb = skb_queue_empty(&sk->sk_write_queue);
1301 skb = sk_stream_alloc_skb(sk,
1302 select_size(sk, sg, first_skb),
1306 goto wait_for_memory;
1308 process_backlog = true;
1310 * Check whether we can use HW checksum.
1312 if (sk_check_csum_caps(sk))
1313 skb->ip_summed = CHECKSUM_PARTIAL;
1315 skb_entail(sk, skb);
1319 /* All packets are restored as if they have
1320 * already been sent. skb_mstamp isn't set to
1321 * avoid wrong rtt estimation.
1324 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1327 /* Try to append data to the end of skb. */
1328 if (copy > msg_data_left(msg))
1329 copy = msg_data_left(msg);
1331 /* Where to copy to? */
1332 if (skb_availroom(skb) > 0) {
1333 /* We have some space in skb head. Superb! */
1334 copy = min_t(int, copy, skb_availroom(skb));
1335 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1338 } else if (!uarg || !uarg->zerocopy) {
1340 int i = skb_shinfo(skb)->nr_frags;
1341 struct page_frag *pfrag = sk_page_frag(sk);
1343 if (!sk_page_frag_refill(sk, pfrag))
1344 goto wait_for_memory;
1346 if (!skb_can_coalesce(skb, i, pfrag->page,
1348 if (i >= sysctl_max_skb_frags || !sg) {
1349 tcp_mark_push(tp, skb);
1355 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1357 if (!sk_wmem_schedule(sk, copy))
1358 goto wait_for_memory;
1360 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1367 /* Update the skb. */
1369 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1371 skb_fill_page_desc(skb, i, pfrag->page,
1372 pfrag->offset, copy);
1373 page_ref_inc(pfrag->page);
1375 pfrag->offset += copy;
1377 err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
1378 if (err == -EMSGSIZE || err == -EEXIST)
1386 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1388 tp->write_seq += copy;
1389 TCP_SKB_CB(skb)->end_seq += copy;
1390 tcp_skb_pcount_set(skb, 0);
1393 if (!msg_data_left(msg)) {
1394 if (unlikely(flags & MSG_EOR))
1395 TCP_SKB_CB(skb)->eor = 1;
1399 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1402 if (forced_push(tp)) {
1403 tcp_mark_push(tp, skb);
1404 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1405 } else if (skb == tcp_send_head(sk))
1406 tcp_push_one(sk, mss_now);
1410 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1413 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1414 TCP_NAGLE_PUSH, size_goal);
1416 err = sk_stream_wait_memory(sk, &timeo);
1420 mss_now = tcp_send_mss(sk, &size_goal, flags);
1425 tcp_tx_timestamp(sk, sockc.tsflags, tcp_write_queue_tail(sk));
1426 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1429 sock_zerocopy_put(uarg);
1430 return copied + copied_syn;
1433 skb = tcp_write_queue_tail(sk);
1435 tcp_remove_empty_skb(sk, skb);
1437 if (copied + copied_syn)
1440 sock_zerocopy_put_abort(uarg);
1441 err = sk_stream_error(sk, flags, err);
1442 /* make sure we wake any epoll edge trigger waiter */
1443 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
1445 sk->sk_write_space(sk);
1446 tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
1450 EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
1452 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1457 ret = tcp_sendmsg_locked(sk, msg, size);
1462 EXPORT_SYMBOL(tcp_sendmsg);
1465 * Handle reading urgent data. BSD has very simple semantics for
1466 * this, no blocking and very strange errors 8)
1469 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1471 struct tcp_sock *tp = tcp_sk(sk);
1473 /* No URG data to read. */
1474 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1475 tp->urg_data == TCP_URG_READ)
1476 return -EINVAL; /* Yes this is right ! */
1478 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1481 if (tp->urg_data & TCP_URG_VALID) {
1483 char c = tp->urg_data;
1485 if (!(flags & MSG_PEEK))
1486 tp->urg_data = TCP_URG_READ;
1488 /* Read urgent data. */
1489 msg->msg_flags |= MSG_OOB;
1492 if (!(flags & MSG_TRUNC))
1493 err = memcpy_to_msg(msg, &c, 1);
1496 msg->msg_flags |= MSG_TRUNC;
1498 return err ? -EFAULT : len;
1501 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1504 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1505 * the available implementations agree in this case:
1506 * this call should never block, independent of the
1507 * blocking state of the socket.
1508 * Mike <pall@rz.uni-karlsruhe.de>
1513 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1515 struct sk_buff *skb;
1516 int copied = 0, err = 0;
1518 /* XXX -- need to support SO_PEEK_OFF */
1520 skb_queue_walk(&sk->sk_write_queue, skb) {
1521 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1528 return err ?: copied;
1531 /* Clean up the receive buffer for full frames taken by the user,
1532 * then send an ACK if necessary. COPIED is the number of bytes
1533 * tcp_recvmsg has given to the user so far, it speeds up the
1534 * calculation of whether or not we must ACK for the sake of
1537 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1539 struct tcp_sock *tp = tcp_sk(sk);
1540 bool time_to_ack = false;
1542 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1544 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1545 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1546 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1548 if (inet_csk_ack_scheduled(sk)) {
1549 const struct inet_connection_sock *icsk = inet_csk(sk);
1550 /* Delayed ACKs frequently hit locked sockets during bulk
1552 if (icsk->icsk_ack.blocked ||
1553 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1554 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1556 * If this read emptied read buffer, we send ACK, if
1557 * connection is not bidirectional, user drained
1558 * receive buffer and there was a small segment
1562 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1563 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1564 !icsk->icsk_ack.pingpong)) &&
1565 !atomic_read(&sk->sk_rmem_alloc)))
1569 /* We send an ACK if we can now advertise a non-zero window
1570 * which has been raised "significantly".
1572 * Even if window raised up to infinity, do not send window open ACK
1573 * in states, where we will not receive more. It is useless.
1575 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1576 __u32 rcv_window_now = tcp_receive_window(tp);
1578 /* Optimize, __tcp_select_window() is not cheap. */
1579 if (2*rcv_window_now <= tp->window_clamp) {
1580 __u32 new_window = __tcp_select_window(sk);
1582 /* Send ACK now, if this read freed lots of space
1583 * in our buffer. Certainly, new_window is new window.
1584 * We can advertise it now, if it is not less than current one.
1585 * "Lots" means "at least twice" here.
1587 if (new_window && new_window >= 2 * rcv_window_now)
1595 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1597 struct sk_buff *skb;
1600 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1601 offset = seq - TCP_SKB_CB(skb)->seq;
1602 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1603 pr_err_once("%s: found a SYN, please report !\n", __func__);
1606 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1610 /* This looks weird, but this can happen if TCP collapsing
1611 * splitted a fat GRO packet, while we released socket lock
1612 * in skb_splice_bits()
1614 sk_eat_skb(sk, skb);
1620 * This routine provides an alternative to tcp_recvmsg() for routines
1621 * that would like to handle copying from skbuffs directly in 'sendfile'
1624 * - It is assumed that the socket was locked by the caller.
1625 * - The routine does not block.
1626 * - At present, there is no support for reading OOB data
1627 * or for 'peeking' the socket using this routine
1628 * (although both would be easy to implement).
1630 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1631 sk_read_actor_t recv_actor)
1633 struct sk_buff *skb;
1634 struct tcp_sock *tp = tcp_sk(sk);
1635 u32 seq = tp->copied_seq;
1639 if (sk->sk_state == TCP_LISTEN)
1641 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1642 if (offset < skb->len) {
1646 len = skb->len - offset;
1647 /* Stop reading if we hit a patch of urgent data */
1649 u32 urg_offset = tp->urg_seq - seq;
1650 if (urg_offset < len)
1655 used = recv_actor(desc, skb, offset, len);
1661 if (WARN_ON_ONCE(used > len))
1667 /* If recv_actor drops the lock (e.g. TCP splice
1668 * receive) the skb pointer might be invalid when
1669 * getting here: tcp_collapse might have deleted it
1670 * while aggregating skbs from the socket queue.
1672 skb = tcp_recv_skb(sk, seq - 1, &offset);
1675 /* TCP coalescing might have appended data to the skb.
1676 * Try to splice more frags
1678 if (offset + 1 != skb->len)
1681 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1682 sk_eat_skb(sk, skb);
1686 sk_eat_skb(sk, skb);
1689 tp->copied_seq = seq;
1691 tp->copied_seq = seq;
1693 tcp_rcv_space_adjust(sk);
1695 /* Clean up data we have read: This will do ACK frames. */
1697 tcp_recv_skb(sk, seq, &offset);
1698 tcp_cleanup_rbuf(sk, copied);
1702 EXPORT_SYMBOL(tcp_read_sock);
1704 int tcp_peek_len(struct socket *sock)
1706 return tcp_inq(sock->sk);
1708 EXPORT_SYMBOL(tcp_peek_len);
1710 static void tcp_update_recv_tstamps(struct sk_buff *skb,
1711 struct scm_timestamping *tss)
1714 tss->ts[0] = ktime_to_timespec(skb->tstamp);
1716 tss->ts[0] = (struct timespec) {0};
1718 if (skb_hwtstamps(skb)->hwtstamp)
1719 tss->ts[2] = ktime_to_timespec(skb_hwtstamps(skb)->hwtstamp);
1721 tss->ts[2] = (struct timespec) {0};
1724 /* Similar to __sock_recv_timestamp, but does not require an skb */
1725 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
1726 struct scm_timestamping *tss)
1729 bool has_timestamping = false;
1731 if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
1732 if (sock_flag(sk, SOCK_RCVTSTAMP)) {
1733 if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
1734 put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS,
1735 sizeof(tss->ts[0]), &tss->ts[0]);
1737 tv.tv_sec = tss->ts[0].tv_sec;
1738 tv.tv_usec = tss->ts[0].tv_nsec / 1000;
1740 put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
1745 if (sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE)
1746 has_timestamping = true;
1748 tss->ts[0] = (struct timespec) {0};
1751 if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
1752 if (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)
1753 has_timestamping = true;
1755 tss->ts[2] = (struct timespec) {0};
1758 if (has_timestamping) {
1759 tss->ts[1] = (struct timespec) {0};
1760 put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING,
1766 * This routine copies from a sock struct into the user buffer.
1768 * Technical note: in 2.3 we work on _locked_ socket, so that
1769 * tricks with *seq access order and skb->users are not required.
1770 * Probably, code can be easily improved even more.
1773 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
1774 int flags, int *addr_len)
1776 struct tcp_sock *tp = tcp_sk(sk);
1782 int target; /* Read at least this many bytes */
1784 struct sk_buff *skb, *last;
1786 struct scm_timestamping tss;
1787 bool has_tss = false;
1789 if (unlikely(flags & MSG_ERRQUEUE))
1790 return inet_recv_error(sk, msg, len, addr_len);
1792 if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue) &&
1793 (sk->sk_state == TCP_ESTABLISHED))
1794 sk_busy_loop(sk, nonblock);
1799 if (sk->sk_state == TCP_LISTEN)
1802 timeo = sock_rcvtimeo(sk, nonblock);
1804 /* Urgent data needs to be handled specially. */
1805 if (flags & MSG_OOB)
1808 if (unlikely(tp->repair)) {
1810 if (!(flags & MSG_PEEK))
1813 if (tp->repair_queue == TCP_SEND_QUEUE)
1817 if (tp->repair_queue == TCP_NO_QUEUE)
1820 /* 'common' recv queue MSG_PEEK-ing */
1823 seq = &tp->copied_seq;
1824 if (flags & MSG_PEEK) {
1825 peek_seq = tp->copied_seq;
1829 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1834 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1835 if (tp->urg_data && tp->urg_seq == *seq) {
1838 if (signal_pending(current)) {
1839 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1844 /* Next get a buffer. */
1846 last = skb_peek_tail(&sk->sk_receive_queue);
1847 skb_queue_walk(&sk->sk_receive_queue, skb) {
1849 /* Now that we have two receive queues this
1852 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1853 "TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
1854 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1858 offset = *seq - TCP_SKB_CB(skb)->seq;
1859 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1860 pr_err_once("%s: found a SYN, please report !\n", __func__);
1863 if (offset < skb->len)
1865 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1867 WARN(!(flags & MSG_PEEK),
1868 "TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
1869 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1872 /* Well, if we have backlog, try to process it now yet. */
1874 if (copied >= target && !sk->sk_backlog.tail)
1879 sk->sk_state == TCP_CLOSE ||
1880 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1882 signal_pending(current))
1885 if (sock_flag(sk, SOCK_DONE))
1889 copied = sock_error(sk);
1893 if (sk->sk_shutdown & RCV_SHUTDOWN)
1896 if (sk->sk_state == TCP_CLOSE) {
1897 if (!sock_flag(sk, SOCK_DONE)) {
1898 /* This occurs when user tries to read
1899 * from never connected socket.
1912 if (signal_pending(current)) {
1913 copied = sock_intr_errno(timeo);
1918 tcp_cleanup_rbuf(sk, copied);
1920 if (copied >= target) {
1921 /* Do not sleep, just process backlog. */
1925 sk_wait_data(sk, &timeo, last);
1928 if ((flags & MSG_PEEK) &&
1929 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1930 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1932 task_pid_nr(current));
1933 peek_seq = tp->copied_seq;
1938 /* Ok so how much can we use? */
1939 used = skb->len - offset;
1943 /* Do we have urgent data here? */
1945 u32 urg_offset = tp->urg_seq - *seq;
1946 if (urg_offset < used) {
1948 if (!sock_flag(sk, SOCK_URGINLINE)) {
1961 if (!(flags & MSG_TRUNC)) {
1962 err = skb_copy_datagram_msg(skb, offset, msg, used);
1964 /* Exception. Bailout! */
1975 tcp_rcv_space_adjust(sk);
1978 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1980 tcp_fast_path_check(sk);
1983 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1984 tcp_update_recv_tstamps(skb, &tss);
1988 if (used + offset < skb->len)
1991 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1993 if (!(flags & MSG_PEEK))
1994 sk_eat_skb(sk, skb);
1998 /* Process the FIN. */
2000 if (!(flags & MSG_PEEK))
2001 sk_eat_skb(sk, skb);
2005 /* According to UNIX98, msg_name/msg_namelen are ignored
2006 * on connected socket. I was just happy when found this 8) --ANK
2010 tcp_recv_timestamp(msg, sk, &tss);
2012 /* Clean up data we have read: This will do ACK frames. */
2013 tcp_cleanup_rbuf(sk, copied);
2023 err = tcp_recv_urg(sk, msg, len, flags);
2027 err = tcp_peek_sndq(sk, msg, len);
2030 EXPORT_SYMBOL(tcp_recvmsg);
2032 void tcp_set_state(struct sock *sk, int state)
2034 int oldstate = sk->sk_state;
2037 case TCP_ESTABLISHED:
2038 if (oldstate != TCP_ESTABLISHED)
2039 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2043 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
2044 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
2046 sk->sk_prot->unhash(sk);
2047 if (inet_csk(sk)->icsk_bind_hash &&
2048 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2052 if (oldstate == TCP_ESTABLISHED)
2053 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2056 /* Change state AFTER socket is unhashed to avoid closed
2057 * socket sitting in hash tables.
2059 sk_state_store(sk, state);
2062 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
2065 EXPORT_SYMBOL_GPL(tcp_set_state);
2068 * State processing on a close. This implements the state shift for
2069 * sending our FIN frame. Note that we only send a FIN for some
2070 * states. A shutdown() may have already sent the FIN, or we may be
2074 static const unsigned char new_state[16] = {
2075 /* current state: new state: action: */
2076 [0 /* (Invalid) */] = TCP_CLOSE,
2077 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2078 [TCP_SYN_SENT] = TCP_CLOSE,
2079 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2080 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2081 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2082 [TCP_TIME_WAIT] = TCP_CLOSE,
2083 [TCP_CLOSE] = TCP_CLOSE,
2084 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2085 [TCP_LAST_ACK] = TCP_LAST_ACK,
2086 [TCP_LISTEN] = TCP_CLOSE,
2087 [TCP_CLOSING] = TCP_CLOSING,
2088 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2091 static int tcp_close_state(struct sock *sk)
2093 int next = (int)new_state[sk->sk_state];
2094 int ns = next & TCP_STATE_MASK;
2096 tcp_set_state(sk, ns);
2098 return next & TCP_ACTION_FIN;
2102 * Shutdown the sending side of a connection. Much like close except
2103 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2106 void tcp_shutdown(struct sock *sk, int how)
2108 /* We need to grab some memory, and put together a FIN,
2109 * and then put it into the queue to be sent.
2110 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2112 if (!(how & SEND_SHUTDOWN))
2115 /* If we've already sent a FIN, or it's a closed state, skip this. */
2116 if ((1 << sk->sk_state) &
2117 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2118 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2119 /* Clear out any half completed packets. FIN if needed. */
2120 if (tcp_close_state(sk))
2124 EXPORT_SYMBOL(tcp_shutdown);
2126 bool tcp_check_oom(struct sock *sk, int shift)
2128 bool too_many_orphans, out_of_socket_memory;
2130 too_many_orphans = tcp_too_many_orphans(sk, shift);
2131 out_of_socket_memory = tcp_out_of_memory(sk);
2133 if (too_many_orphans)
2134 net_info_ratelimited("too many orphaned sockets\n");
2135 if (out_of_socket_memory)
2136 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2137 return too_many_orphans || out_of_socket_memory;
2140 void tcp_close(struct sock *sk, long timeout)
2142 struct sk_buff *skb;
2143 int data_was_unread = 0;
2147 sk->sk_shutdown = SHUTDOWN_MASK;
2149 if (sk->sk_state == TCP_LISTEN) {
2150 tcp_set_state(sk, TCP_CLOSE);
2153 inet_csk_listen_stop(sk);
2155 goto adjudge_to_death;
2158 /* We need to flush the recv. buffs. We do this only on the
2159 * descriptor close, not protocol-sourced closes, because the
2160 * reader process may not have drained the data yet!
2162 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2163 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2165 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2167 data_was_unread += len;
2173 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2174 if (sk->sk_state == TCP_CLOSE)
2175 goto adjudge_to_death;
2177 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2178 * data was lost. To witness the awful effects of the old behavior of
2179 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2180 * GET in an FTP client, suspend the process, wait for the client to
2181 * advertise a zero window, then kill -9 the FTP client, wheee...
2182 * Note: timeout is always zero in such a case.
2184 if (unlikely(tcp_sk(sk)->repair)) {
2185 sk->sk_prot->disconnect(sk, 0);
2186 } else if (data_was_unread) {
2187 /* Unread data was tossed, zap the connection. */
2188 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2189 tcp_set_state(sk, TCP_CLOSE);
2190 tcp_send_active_reset(sk, sk->sk_allocation);
2191 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2192 /* Check zero linger _after_ checking for unread data. */
2193 sk->sk_prot->disconnect(sk, 0);
2194 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2195 } else if (tcp_close_state(sk)) {
2196 /* We FIN if the application ate all the data before
2197 * zapping the connection.
2200 /* RED-PEN. Formally speaking, we have broken TCP state
2201 * machine. State transitions:
2203 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2204 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2205 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2207 * are legal only when FIN has been sent (i.e. in window),
2208 * rather than queued out of window. Purists blame.
2210 * F.e. "RFC state" is ESTABLISHED,
2211 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2213 * The visible declinations are that sometimes
2214 * we enter time-wait state, when it is not required really
2215 * (harmless), do not send active resets, when they are
2216 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2217 * they look as CLOSING or LAST_ACK for Linux)
2218 * Probably, I missed some more holelets.
2220 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2221 * in a single packet! (May consider it later but will
2222 * probably need API support or TCP_CORK SYN-ACK until
2223 * data is written and socket is closed.)
2228 sk_stream_wait_close(sk, timeout);
2231 state = sk->sk_state;
2237 /* remove backlog if any, without releasing ownership. */
2240 percpu_counter_inc(sk->sk_prot->orphan_count);
2242 /* Have we already been destroyed by a softirq or backlog? */
2243 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2246 /* This is a (useful) BSD violating of the RFC. There is a
2247 * problem with TCP as specified in that the other end could
2248 * keep a socket open forever with no application left this end.
2249 * We use a 1 minute timeout (about the same as BSD) then kill
2250 * our end. If they send after that then tough - BUT: long enough
2251 * that we won't make the old 4*rto = almost no time - whoops
2254 * Nope, it was not mistake. It is really desired behaviour
2255 * f.e. on http servers, when such sockets are useless, but
2256 * consume significant resources. Let's do it with special
2257 * linger2 option. --ANK
2260 if (sk->sk_state == TCP_FIN_WAIT2) {
2261 struct tcp_sock *tp = tcp_sk(sk);
2262 if (tp->linger2 < 0) {
2263 tcp_set_state(sk, TCP_CLOSE);
2264 tcp_send_active_reset(sk, GFP_ATOMIC);
2265 __NET_INC_STATS(sock_net(sk),
2266 LINUX_MIB_TCPABORTONLINGER);
2268 const int tmo = tcp_fin_time(sk);
2270 if (tmo > TCP_TIMEWAIT_LEN) {
2271 inet_csk_reset_keepalive_timer(sk,
2272 tmo - TCP_TIMEWAIT_LEN);
2274 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2279 if (sk->sk_state != TCP_CLOSE) {
2281 if (tcp_check_oom(sk, 0)) {
2282 tcp_set_state(sk, TCP_CLOSE);
2283 tcp_send_active_reset(sk, GFP_ATOMIC);
2284 __NET_INC_STATS(sock_net(sk),
2285 LINUX_MIB_TCPABORTONMEMORY);
2286 } else if (!check_net(sock_net(sk))) {
2287 /* Not possible to send reset; just close */
2288 tcp_set_state(sk, TCP_CLOSE);
2292 if (sk->sk_state == TCP_CLOSE) {
2293 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2294 /* We could get here with a non-NULL req if the socket is
2295 * aborted (e.g., closed with unread data) before 3WHS
2299 reqsk_fastopen_remove(sk, req, false);
2300 inet_csk_destroy_sock(sk);
2302 /* Otherwise, socket is reprieved until protocol close. */
2310 EXPORT_SYMBOL(tcp_close);
2312 /* These states need RST on ABORT according to RFC793 */
2314 static inline bool tcp_need_reset(int state)
2316 return (1 << state) &
2317 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2318 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2321 int tcp_disconnect(struct sock *sk, int flags)
2323 struct inet_sock *inet = inet_sk(sk);
2324 struct inet_connection_sock *icsk = inet_csk(sk);
2325 struct tcp_sock *tp = tcp_sk(sk);
2327 int old_state = sk->sk_state;
2329 if (old_state != TCP_CLOSE)
2330 tcp_set_state(sk, TCP_CLOSE);
2332 /* ABORT function of RFC793 */
2333 if (old_state == TCP_LISTEN) {
2334 inet_csk_listen_stop(sk);
2335 } else if (unlikely(tp->repair)) {
2336 sk->sk_err = ECONNABORTED;
2337 } else if (tcp_need_reset(old_state) ||
2338 (tp->snd_nxt != tp->write_seq &&
2339 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2340 /* The last check adjusts for discrepancy of Linux wrt. RFC
2343 tcp_send_active_reset(sk, gfp_any());
2344 sk->sk_err = ECONNRESET;
2345 } else if (old_state == TCP_SYN_SENT)
2346 sk->sk_err = ECONNRESET;
2348 tcp_clear_xmit_timers(sk);
2349 __skb_queue_purge(&sk->sk_receive_queue);
2350 tcp_write_queue_purge(sk);
2351 tcp_fastopen_active_disable_ofo_check(sk);
2352 skb_rbtree_purge(&tp->out_of_order_queue);
2354 inet->inet_dport = 0;
2356 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2357 inet_reset_saddr(sk);
2359 sk->sk_shutdown = 0;
2360 sock_reset_flag(sk, SOCK_DONE);
2362 tp->write_seq += tp->max_window + 2;
2363 if (tp->write_seq == 0)
2366 icsk->icsk_probes_out = 0;
2367 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2368 tp->snd_cwnd_cnt = 0;
2369 tp->is_cwnd_limited = 0;
2370 tp->max_packets_out = 0;
2371 tp->window_clamp = 0;
2373 if (icsk->icsk_ca_ops->release)
2374 icsk->icsk_ca_ops->release(sk);
2375 memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
2376 tcp_set_ca_state(sk, TCP_CA_Open);
2377 tp->is_sack_reneg = 0;
2378 tcp_clear_retrans(tp);
2379 tp->total_retrans = 0;
2380 inet_csk_delack_init(sk);
2381 /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
2382 * issue in __tcp_select_window()
2384 icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
2385 tcp_init_send_head(sk);
2386 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2388 dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL));
2389 tcp_saved_syn_free(tp);
2392 tp->bytes_acked = 0;
2393 tp->bytes_received = 0;
2394 tp->data_segs_in = 0;
2395 tp->data_segs_out = 0;
2397 /* Clean up fastopen related fields */
2398 tcp_free_fastopen_req(tp);
2399 inet->defer_connect = 0;
2401 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2403 if (sk->sk_frag.page) {
2404 put_page(sk->sk_frag.page);
2405 sk->sk_frag.page = NULL;
2406 sk->sk_frag.offset = 0;
2409 sk->sk_error_report(sk);
2412 EXPORT_SYMBOL(tcp_disconnect);
2414 static inline bool tcp_can_repair_sock(const struct sock *sk)
2416 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2417 (sk->sk_state != TCP_LISTEN);
2420 static int tcp_repair_set_window(struct tcp_sock *tp, char __user *optbuf, int len)
2422 struct tcp_repair_window opt;
2427 if (len != sizeof(opt))
2430 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2433 if (opt.max_window < opt.snd_wnd)
2436 if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
2439 if (after(opt.rcv_wup, tp->rcv_nxt))
2442 tp->snd_wl1 = opt.snd_wl1;
2443 tp->snd_wnd = opt.snd_wnd;
2444 tp->max_window = opt.max_window;
2446 tp->rcv_wnd = opt.rcv_wnd;
2447 tp->rcv_wup = opt.rcv_wup;
2452 static int tcp_repair_options_est(struct sock *sk,
2453 struct tcp_repair_opt __user *optbuf, unsigned int len)
2455 struct tcp_sock *tp = tcp_sk(sk);
2456 struct tcp_repair_opt opt;
2458 while (len >= sizeof(opt)) {
2459 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2465 switch (opt.opt_code) {
2467 tp->rx_opt.mss_clamp = opt.opt_val;
2472 u16 snd_wscale = opt.opt_val & 0xFFFF;
2473 u16 rcv_wscale = opt.opt_val >> 16;
2475 if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
2478 tp->rx_opt.snd_wscale = snd_wscale;
2479 tp->rx_opt.rcv_wscale = rcv_wscale;
2480 tp->rx_opt.wscale_ok = 1;
2483 case TCPOPT_SACK_PERM:
2484 if (opt.opt_val != 0)
2487 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2488 if (sysctl_tcp_fack)
2489 tcp_enable_fack(tp);
2491 case TCPOPT_TIMESTAMP:
2492 if (opt.opt_val != 0)
2495 tp->rx_opt.tstamp_ok = 1;
2504 * Socket option code for TCP.
2506 static int do_tcp_setsockopt(struct sock *sk, int level,
2507 int optname, char __user *optval, unsigned int optlen)
2509 struct tcp_sock *tp = tcp_sk(sk);
2510 struct inet_connection_sock *icsk = inet_csk(sk);
2511 struct net *net = sock_net(sk);
2515 /* These are data/string values, all the others are ints */
2517 case TCP_CONGESTION: {
2518 char name[TCP_CA_NAME_MAX];
2523 val = strncpy_from_user(name, optval,
2524 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2530 err = tcp_set_congestion_control(sk, name, true, true,
2531 ns_capable(sock_net(sk)->user_ns,
2537 char name[TCP_ULP_NAME_MAX];
2542 val = strncpy_from_user(name, optval,
2543 min_t(long, TCP_ULP_NAME_MAX - 1,
2550 err = tcp_set_ulp(sk, name);
2559 if (optlen < sizeof(int))
2562 if (get_user(val, (int __user *)optval))
2569 /* Values greater than interface MTU won't take effect. However
2570 * at the point when this call is done we typically don't yet
2571 * know which interface is going to be used
2573 if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
2577 tp->rx_opt.user_mss = val;
2582 /* TCP_NODELAY is weaker than TCP_CORK, so that
2583 * this option on corked socket is remembered, but
2584 * it is not activated until cork is cleared.
2586 * However, when TCP_NODELAY is set we make
2587 * an explicit push, which overrides even TCP_CORK
2588 * for currently queued segments.
2590 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2591 tcp_push_pending_frames(sk);
2593 tp->nonagle &= ~TCP_NAGLE_OFF;
2597 case TCP_THIN_LINEAR_TIMEOUTS:
2598 if (val < 0 || val > 1)
2604 case TCP_THIN_DUPACK:
2605 if (val < 0 || val > 1)
2610 if (!tcp_can_repair_sock(sk))
2612 else if (val == 1) {
2614 sk->sk_reuse = SK_FORCE_REUSE;
2615 tp->repair_queue = TCP_NO_QUEUE;
2616 } else if (val == 0) {
2618 sk->sk_reuse = SK_NO_REUSE;
2619 tcp_send_window_probe(sk);
2625 case TCP_REPAIR_QUEUE:
2628 else if ((unsigned int)val < TCP_QUEUES_NR)
2629 tp->repair_queue = val;
2635 if (sk->sk_state != TCP_CLOSE)
2637 else if (tp->repair_queue == TCP_SEND_QUEUE)
2638 tp->write_seq = val;
2639 else if (tp->repair_queue == TCP_RECV_QUEUE)
2645 case TCP_REPAIR_OPTIONS:
2648 else if (sk->sk_state == TCP_ESTABLISHED)
2649 err = tcp_repair_options_est(sk,
2650 (struct tcp_repair_opt __user *)optval,
2657 /* When set indicates to always queue non-full frames.
2658 * Later the user clears this option and we transmit
2659 * any pending partial frames in the queue. This is
2660 * meant to be used alongside sendfile() to get properly
2661 * filled frames when the user (for example) must write
2662 * out headers with a write() call first and then use
2663 * sendfile to send out the data parts.
2665 * TCP_CORK can be set together with TCP_NODELAY and it is
2666 * stronger than TCP_NODELAY.
2669 tp->nonagle |= TCP_NAGLE_CORK;
2671 tp->nonagle &= ~TCP_NAGLE_CORK;
2672 if (tp->nonagle&TCP_NAGLE_OFF)
2673 tp->nonagle |= TCP_NAGLE_PUSH;
2674 tcp_push_pending_frames(sk);
2679 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2682 tp->keepalive_time = val * HZ;
2683 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2684 !((1 << sk->sk_state) &
2685 (TCPF_CLOSE | TCPF_LISTEN))) {
2686 u32 elapsed = keepalive_time_elapsed(tp);
2687 if (tp->keepalive_time > elapsed)
2688 elapsed = tp->keepalive_time - elapsed;
2691 inet_csk_reset_keepalive_timer(sk, elapsed);
2696 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2699 tp->keepalive_intvl = val * HZ;
2702 if (val < 1 || val > MAX_TCP_KEEPCNT)
2705 tp->keepalive_probes = val;
2708 if (val < 1 || val > MAX_TCP_SYNCNT)
2711 icsk->icsk_syn_retries = val;
2715 if (val < 0 || val > 1)
2724 else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
2727 tp->linger2 = val * HZ;
2730 case TCP_DEFER_ACCEPT:
2731 /* Translate value in seconds to number of retransmits */
2732 icsk->icsk_accept_queue.rskq_defer_accept =
2733 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2737 case TCP_WINDOW_CLAMP:
2739 if (sk->sk_state != TCP_CLOSE) {
2743 tp->window_clamp = 0;
2745 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2746 SOCK_MIN_RCVBUF / 2 : val;
2751 icsk->icsk_ack.pingpong = 1;
2753 icsk->icsk_ack.pingpong = 0;
2754 if ((1 << sk->sk_state) &
2755 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2756 inet_csk_ack_scheduled(sk)) {
2757 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2758 tcp_cleanup_rbuf(sk, 1);
2760 icsk->icsk_ack.pingpong = 1;
2765 #ifdef CONFIG_TCP_MD5SIG
2767 case TCP_MD5SIG_EXT:
2768 err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
2771 case TCP_USER_TIMEOUT:
2772 /* Cap the max time in ms TCP will retry or probe the window
2773 * before giving up and aborting (ETIMEDOUT) a connection.
2778 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2782 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2784 tcp_fastopen_init_key_once(true);
2786 fastopen_queue_tune(sk, val);
2791 case TCP_FASTOPEN_CONNECT:
2792 if (val > 1 || val < 0) {
2794 } else if (sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) {
2795 if (sk->sk_state == TCP_CLOSE)
2796 tp->fastopen_connect = val;
2807 tp->tsoffset = val - tcp_time_stamp_raw();
2809 case TCP_REPAIR_WINDOW:
2810 err = tcp_repair_set_window(tp, optval, optlen);
2812 case TCP_NOTSENT_LOWAT:
2813 tp->notsent_lowat = val;
2814 sk->sk_write_space(sk);
2825 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2826 unsigned int optlen)
2828 const struct inet_connection_sock *icsk = inet_csk(sk);
2830 if (level != SOL_TCP)
2831 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2833 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2835 EXPORT_SYMBOL(tcp_setsockopt);
2837 #ifdef CONFIG_COMPAT
2838 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2839 char __user *optval, unsigned int optlen)
2841 if (level != SOL_TCP)
2842 return inet_csk_compat_setsockopt(sk, level, optname,
2844 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2846 EXPORT_SYMBOL(compat_tcp_setsockopt);
2849 static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
2850 struct tcp_info *info)
2852 u64 stats[__TCP_CHRONO_MAX], total = 0;
2855 for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
2856 stats[i] = tp->chrono_stat[i - 1];
2857 if (i == tp->chrono_type)
2858 stats[i] += tcp_jiffies32 - tp->chrono_start;
2859 stats[i] *= USEC_PER_SEC / HZ;
2863 info->tcpi_busy_time = total;
2864 info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED];
2865 info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED];
2868 /* Return information about state of tcp endpoint in API format. */
2869 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2871 const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
2872 const struct inet_connection_sock *icsk = inet_csk(sk);
2878 memset(info, 0, sizeof(*info));
2879 if (sk->sk_type != SOCK_STREAM)
2882 info->tcpi_state = sk_state_load(sk);
2884 /* Report meaningful fields for all TCP states, including listeners */
2885 rate = READ_ONCE(sk->sk_pacing_rate);
2886 rate64 = rate != ~0U ? rate : ~0ULL;
2887 info->tcpi_pacing_rate = rate64;
2889 rate = READ_ONCE(sk->sk_max_pacing_rate);
2890 rate64 = rate != ~0U ? rate : ~0ULL;
2891 info->tcpi_max_pacing_rate = rate64;
2893 info->tcpi_reordering = tp->reordering;
2894 info->tcpi_snd_cwnd = tp->snd_cwnd;
2896 if (info->tcpi_state == TCP_LISTEN) {
2897 /* listeners aliased fields :
2898 * tcpi_unacked -> Number of children ready for accept()
2899 * tcpi_sacked -> max backlog
2901 info->tcpi_unacked = sk->sk_ack_backlog;
2902 info->tcpi_sacked = sk->sk_max_ack_backlog;
2906 slow = lock_sock_fast(sk);
2908 info->tcpi_ca_state = icsk->icsk_ca_state;
2909 info->tcpi_retransmits = icsk->icsk_retransmits;
2910 info->tcpi_probes = icsk->icsk_probes_out;
2911 info->tcpi_backoff = icsk->icsk_backoff;
2913 if (tp->rx_opt.tstamp_ok)
2914 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2915 if (tcp_is_sack(tp))
2916 info->tcpi_options |= TCPI_OPT_SACK;
2917 if (tp->rx_opt.wscale_ok) {
2918 info->tcpi_options |= TCPI_OPT_WSCALE;
2919 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2920 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2923 if (tp->ecn_flags & TCP_ECN_OK)
2924 info->tcpi_options |= TCPI_OPT_ECN;
2925 if (tp->ecn_flags & TCP_ECN_SEEN)
2926 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2927 if (tp->syn_data_acked)
2928 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2930 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2931 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2932 info->tcpi_snd_mss = tp->mss_cache;
2933 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2935 info->tcpi_unacked = tp->packets_out;
2936 info->tcpi_sacked = tp->sacked_out;
2938 info->tcpi_lost = tp->lost_out;
2939 info->tcpi_retrans = tp->retrans_out;
2940 info->tcpi_fackets = tp->fackets_out;
2942 now = tcp_jiffies32;
2943 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2944 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2945 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2947 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2948 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2949 info->tcpi_rtt = tp->srtt_us >> 3;
2950 info->tcpi_rttvar = tp->mdev_us >> 2;
2951 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2952 info->tcpi_advmss = tp->advmss;
2954 info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
2955 info->tcpi_rcv_space = tp->rcvq_space.space;
2957 info->tcpi_total_retrans = tp->total_retrans;
2959 info->tcpi_bytes_acked = tp->bytes_acked;
2960 info->tcpi_bytes_received = tp->bytes_received;
2961 info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
2962 tcp_get_info_chrono_stats(tp, info);
2964 info->tcpi_segs_out = tp->segs_out;
2965 info->tcpi_segs_in = tp->segs_in;
2967 info->tcpi_min_rtt = tcp_min_rtt(tp);
2968 info->tcpi_data_segs_in = tp->data_segs_in;
2969 info->tcpi_data_segs_out = tp->data_segs_out;
2971 info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
2972 rate64 = tcp_compute_delivery_rate(tp);
2974 info->tcpi_delivery_rate = rate64;
2975 unlock_sock_fast(sk, slow);
2977 EXPORT_SYMBOL_GPL(tcp_get_info);
2979 struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
2981 const struct tcp_sock *tp = tcp_sk(sk);
2982 struct sk_buff *stats;
2983 struct tcp_info info;
2987 stats = alloc_skb(7 * nla_total_size_64bit(sizeof(u64)) +
2988 3 * nla_total_size(sizeof(u32)) +
2989 2 * nla_total_size(sizeof(u8)), GFP_ATOMIC);
2993 tcp_get_info_chrono_stats(tp, &info);
2994 nla_put_u64_64bit(stats, TCP_NLA_BUSY,
2995 info.tcpi_busy_time, TCP_NLA_PAD);
2996 nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
2997 info.tcpi_rwnd_limited, TCP_NLA_PAD);
2998 nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
2999 info.tcpi_sndbuf_limited, TCP_NLA_PAD);
3000 nla_put_u64_64bit(stats, TCP_NLA_DATA_SEGS_OUT,
3001 tp->data_segs_out, TCP_NLA_PAD);
3002 nla_put_u64_64bit(stats, TCP_NLA_TOTAL_RETRANS,
3003 tp->total_retrans, TCP_NLA_PAD);
3005 rate = READ_ONCE(sk->sk_pacing_rate);
3006 rate64 = rate != ~0U ? rate : ~0ULL;
3007 nla_put_u64_64bit(stats, TCP_NLA_PACING_RATE, rate64, TCP_NLA_PAD);
3009 rate64 = tcp_compute_delivery_rate(tp);
3010 nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD);
3012 nla_put_u32(stats, TCP_NLA_SND_CWND, tp->snd_cwnd);
3013 nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering);
3014 nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp));
3016 nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits);
3017 nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited);
3021 static int do_tcp_getsockopt(struct sock *sk, int level,
3022 int optname, char __user *optval, int __user *optlen)
3024 struct inet_connection_sock *icsk = inet_csk(sk);
3025 struct tcp_sock *tp = tcp_sk(sk);
3026 struct net *net = sock_net(sk);
3029 if (get_user(len, optlen))
3032 len = min_t(unsigned int, len, sizeof(int));
3039 val = tp->mss_cache;
3040 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
3041 val = tp->rx_opt.user_mss;
3043 val = tp->rx_opt.mss_clamp;
3046 val = !!(tp->nonagle&TCP_NAGLE_OFF);
3049 val = !!(tp->nonagle&TCP_NAGLE_CORK);
3052 val = keepalive_time_when(tp) / HZ;
3055 val = keepalive_intvl_when(tp) / HZ;
3058 val = keepalive_probes(tp);
3061 val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
3066 val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
3068 case TCP_DEFER_ACCEPT:
3069 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
3070 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
3072 case TCP_WINDOW_CLAMP:
3073 val = tp->window_clamp;
3076 struct tcp_info info;
3078 if (get_user(len, optlen))
3081 tcp_get_info(sk, &info);
3083 len = min_t(unsigned int, len, sizeof(info));
3084 if (put_user(len, optlen))
3086 if (copy_to_user(optval, &info, len))
3091 const struct tcp_congestion_ops *ca_ops;
3092 union tcp_cc_info info;
3096 if (get_user(len, optlen))
3099 ca_ops = icsk->icsk_ca_ops;
3100 if (ca_ops && ca_ops->get_info)
3101 sz = ca_ops->get_info(sk, ~0U, &attr, &info);
3103 len = min_t(unsigned int, len, sz);
3104 if (put_user(len, optlen))
3106 if (copy_to_user(optval, &info, len))
3111 val = !icsk->icsk_ack.pingpong;
3114 case TCP_CONGESTION:
3115 if (get_user(len, optlen))
3117 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
3118 if (put_user(len, optlen))
3120 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
3125 if (get_user(len, optlen))
3127 len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
3128 if (!icsk->icsk_ulp_ops) {
3129 if (put_user(0, optlen))
3133 if (put_user(len, optlen))
3135 if (copy_to_user(optval, icsk->icsk_ulp_ops->name, len))
3139 case TCP_THIN_LINEAR_TIMEOUTS:
3143 case TCP_THIN_DUPACK:
3151 case TCP_REPAIR_QUEUE:
3153 val = tp->repair_queue;
3158 case TCP_REPAIR_WINDOW: {
3159 struct tcp_repair_window opt;
3161 if (get_user(len, optlen))
3164 if (len != sizeof(opt))
3170 opt.snd_wl1 = tp->snd_wl1;
3171 opt.snd_wnd = tp->snd_wnd;
3172 opt.max_window = tp->max_window;
3173 opt.rcv_wnd = tp->rcv_wnd;
3174 opt.rcv_wup = tp->rcv_wup;
3176 if (copy_to_user(optval, &opt, len))
3181 if (tp->repair_queue == TCP_SEND_QUEUE)
3182 val = tp->write_seq;
3183 else if (tp->repair_queue == TCP_RECV_QUEUE)
3189 case TCP_USER_TIMEOUT:
3190 val = jiffies_to_msecs(icsk->icsk_user_timeout);
3194 val = icsk->icsk_accept_queue.fastopenq.max_qlen;
3197 case TCP_FASTOPEN_CONNECT:
3198 val = tp->fastopen_connect;
3202 val = tcp_time_stamp_raw() + tp->tsoffset;
3204 case TCP_NOTSENT_LOWAT:
3205 val = tp->notsent_lowat;
3210 case TCP_SAVED_SYN: {
3211 if (get_user(len, optlen))
3215 if (tp->saved_syn) {
3216 if (len < tp->saved_syn[0]) {
3217 if (put_user(tp->saved_syn[0], optlen)) {
3224 len = tp->saved_syn[0];
3225 if (put_user(len, optlen)) {
3229 if (copy_to_user(optval, tp->saved_syn + 1, len)) {
3233 tcp_saved_syn_free(tp);
3238 if (put_user(len, optlen))
3244 return -ENOPROTOOPT;
3247 if (put_user(len, optlen))
3249 if (copy_to_user(optval, &val, len))
3254 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
3257 struct inet_connection_sock *icsk = inet_csk(sk);
3259 if (level != SOL_TCP)
3260 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
3262 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3264 EXPORT_SYMBOL(tcp_getsockopt);
3266 #ifdef CONFIG_COMPAT
3267 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
3268 char __user *optval, int __user *optlen)
3270 if (level != SOL_TCP)
3271 return inet_csk_compat_getsockopt(sk, level, optname,
3273 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3275 EXPORT_SYMBOL(compat_tcp_getsockopt);
3278 #ifdef CONFIG_TCP_MD5SIG
3279 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
3280 static DEFINE_MUTEX(tcp_md5sig_mutex);
3281 static bool tcp_md5sig_pool_populated = false;
3283 static void __tcp_alloc_md5sig_pool(void)
3285 struct crypto_ahash *hash;
3288 hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
3292 for_each_possible_cpu(cpu) {
3293 void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch;
3294 struct ahash_request *req;
3297 scratch = kmalloc_node(sizeof(union tcp_md5sum_block) +
3298 sizeof(struct tcphdr),
3303 per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
3305 if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
3308 req = ahash_request_alloc(hash, GFP_KERNEL);
3312 ahash_request_set_callback(req, 0, NULL, NULL);
3314 per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
3316 /* before setting tcp_md5sig_pool_populated, we must commit all writes
3317 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
3320 /* Paired with READ_ONCE() from tcp_alloc_md5sig_pool()
3321 * and tcp_get_md5sig_pool().
3323 WRITE_ONCE(tcp_md5sig_pool_populated, true);
3326 bool tcp_alloc_md5sig_pool(void)
3328 /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */
3329 if (unlikely(!READ_ONCE(tcp_md5sig_pool_populated))) {
3330 mutex_lock(&tcp_md5sig_mutex);
3332 if (!tcp_md5sig_pool_populated)
3333 __tcp_alloc_md5sig_pool();
3335 mutex_unlock(&tcp_md5sig_mutex);
3337 /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */
3338 return READ_ONCE(tcp_md5sig_pool_populated);
3340 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3344 * tcp_get_md5sig_pool - get md5sig_pool for this user
3346 * We use percpu structure, so if we succeed, we exit with preemption
3347 * and BH disabled, to make sure another thread or softirq handling
3348 * wont try to get same context.
3350 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3354 /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */
3355 if (READ_ONCE(tcp_md5sig_pool_populated)) {
3356 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
3358 return this_cpu_ptr(&tcp_md5sig_pool);
3363 EXPORT_SYMBOL(tcp_get_md5sig_pool);
3365 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3366 const struct sk_buff *skb, unsigned int header_len)
3368 struct scatterlist sg;
3369 const struct tcphdr *tp = tcp_hdr(skb);
3370 struct ahash_request *req = hp->md5_req;
3372 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3373 skb_headlen(skb) - header_len : 0;
3374 const struct skb_shared_info *shi = skb_shinfo(skb);
3375 struct sk_buff *frag_iter;
3377 sg_init_table(&sg, 1);
3379 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3380 ahash_request_set_crypt(req, &sg, NULL, head_data_len);
3381 if (crypto_ahash_update(req))
3384 for (i = 0; i < shi->nr_frags; ++i) {
3385 const struct skb_frag_struct *f = &shi->frags[i];
3386 unsigned int offset = f->page_offset;
3387 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
3389 sg_set_page(&sg, page, skb_frag_size(f),
3390 offset_in_page(offset));
3391 ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
3392 if (crypto_ahash_update(req))
3396 skb_walk_frags(skb, frag_iter)
3397 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3402 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3404 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3406 u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */
3407 struct scatterlist sg;
3409 sg_init_one(&sg, key->key, keylen);
3410 ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen);
3412 /* tcp_md5_do_add() might change key->key under us */
3413 return crypto_ahash_update(hp->md5_req);
3415 EXPORT_SYMBOL(tcp_md5_hash_key);
3419 void tcp_done(struct sock *sk)
3421 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
3423 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3424 TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3426 tcp_set_state(sk, TCP_CLOSE);
3427 tcp_clear_xmit_timers(sk);
3429 reqsk_fastopen_remove(sk, req, false);
3431 sk->sk_shutdown = SHUTDOWN_MASK;
3433 if (!sock_flag(sk, SOCK_DEAD))
3434 sk->sk_state_change(sk);
3436 inet_csk_destroy_sock(sk);
3438 EXPORT_SYMBOL_GPL(tcp_done);
3440 int tcp_abort(struct sock *sk, int err)
3442 if (!sk_fullsock(sk)) {
3443 if (sk->sk_state == TCP_NEW_SYN_RECV) {
3444 struct request_sock *req = inet_reqsk(sk);
3447 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
3454 /* Don't race with userspace socket closes such as tcp_close. */
3457 if (sk->sk_state == TCP_LISTEN) {
3458 tcp_set_state(sk, TCP_CLOSE);
3459 inet_csk_listen_stop(sk);
3462 /* Don't race with BH socket closes such as inet_csk_listen_stop. */
3466 if (!sock_flag(sk, SOCK_DEAD)) {
3468 /* This barrier is coupled with smp_rmb() in tcp_poll() */
3470 sk->sk_error_report(sk);
3471 if (tcp_need_reset(sk->sk_state))
3472 tcp_send_active_reset(sk, GFP_ATOMIC);
3478 tcp_write_queue_purge(sk);
3482 EXPORT_SYMBOL_GPL(tcp_abort);
3484 extern struct tcp_congestion_ops tcp_reno;
3486 static __initdata unsigned long thash_entries;
3487 static int __init set_thash_entries(char *str)
3494 ret = kstrtoul(str, 0, &thash_entries);
3500 __setup("thash_entries=", set_thash_entries);
3502 static void __init tcp_init_mem(void)
3504 unsigned long limit = nr_free_buffer_pages() / 16;
3506 limit = max(limit, 128UL);
3507 sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
3508 sysctl_tcp_mem[1] = limit; /* 6.25 % */
3509 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
3512 void __init tcp_init(void)
3514 int max_rshare, max_wshare, cnt;
3515 unsigned long limit;
3518 BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
3519 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
3520 FIELD_SIZEOF(struct sk_buff, cb));
3522 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3523 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3524 inet_hashinfo_init(&tcp_hashinfo);
3525 tcp_hashinfo.bind_bucket_cachep =
3526 kmem_cache_create("tcp_bind_bucket",
3527 sizeof(struct inet_bind_bucket), 0,
3528 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3530 /* Size and allocate the main established and bind bucket
3533 * The methodology is similar to that of the buffer cache.
3535 tcp_hashinfo.ehash =
3536 alloc_large_system_hash("TCP established",
3537 sizeof(struct inet_ehash_bucket),
3539 17, /* one slot per 128 KB of memory */
3542 &tcp_hashinfo.ehash_mask,
3544 thash_entries ? 0 : 512 * 1024);
3545 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3546 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3548 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3549 panic("TCP: failed to alloc ehash_locks");
3550 tcp_hashinfo.bhash =
3551 alloc_large_system_hash("TCP bind",
3552 sizeof(struct inet_bind_hashbucket),
3553 tcp_hashinfo.ehash_mask + 1,
3554 17, /* one slot per 128 KB of memory */
3556 &tcp_hashinfo.bhash_size,
3560 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3561 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3562 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3563 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3567 cnt = tcp_hashinfo.ehash_mask + 1;
3568 sysctl_tcp_max_orphans = cnt / 2;
3571 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3572 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3573 max_wshare = min(4UL*1024*1024, limit);
3574 max_rshare = min(6UL*1024*1024, limit);
3576 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3577 sysctl_tcp_wmem[1] = 16*1024;
3578 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3580 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3581 sysctl_tcp_rmem[1] = 87380;
3582 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3584 pr_info("Hash tables configured (established %u bind %u)\n",
3585 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3589 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);