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 <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>
272 #include <net/icmp.h>
273 #include <net/inet_common.h>
275 #include <net/xfrm.h>
277 #include <net/netdma.h>
278 #include <net/sock.h>
280 #include <asm/uaccess.h>
281 #include <asm/ioctls.h>
282 #include <net/busy_poll.h>
284 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
286 struct percpu_counter tcp_orphan_count;
287 EXPORT_SYMBOL_GPL(tcp_orphan_count);
289 int sysctl_tcp_wmem[3] __read_mostly;
290 int sysctl_tcp_rmem[3] __read_mostly;
292 EXPORT_SYMBOL(sysctl_tcp_rmem);
293 EXPORT_SYMBOL(sysctl_tcp_wmem);
295 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
296 EXPORT_SYMBOL(tcp_memory_allocated);
299 * Current number of TCP sockets.
301 struct percpu_counter tcp_sockets_allocated;
302 EXPORT_SYMBOL(tcp_sockets_allocated);
307 struct tcp_splice_state {
308 struct pipe_inode_info *pipe;
314 * Pressure flag: try to collapse.
315 * Technical note: it is used by multiple contexts non atomically.
316 * All the __sk_mem_schedule() is of this nature: accounting
317 * is strict, actions are advisory and have some latency.
319 int tcp_memory_pressure __read_mostly;
320 EXPORT_SYMBOL(tcp_memory_pressure);
322 void tcp_enter_memory_pressure(struct sock *sk)
324 if (!tcp_memory_pressure) {
325 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
326 tcp_memory_pressure = 1;
329 EXPORT_SYMBOL(tcp_enter_memory_pressure);
331 /* Convert seconds to retransmits based on initial and max timeout */
332 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
337 int period = timeout;
340 while (seconds > period && res < 255) {
343 if (timeout > rto_max)
351 /* Convert retransmits to seconds based on initial and max timeout */
352 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
360 if (timeout > rto_max)
368 /* Address-family independent initialization for a tcp_sock.
370 * NOTE: A lot of things set to zero explicitly by call to
371 * sk_alloc() so need not be done here.
373 void tcp_init_sock(struct sock *sk)
375 struct inet_connection_sock *icsk = inet_csk(sk);
376 struct tcp_sock *tp = tcp_sk(sk);
378 skb_queue_head_init(&tp->out_of_order_queue);
379 tcp_init_xmit_timers(sk);
380 tcp_prequeue_init(tp);
381 INIT_LIST_HEAD(&tp->tsq_node);
383 icsk->icsk_rto = TCP_TIMEOUT_INIT;
384 tp->mdev = TCP_TIMEOUT_INIT;
386 /* So many TCP implementations out there (incorrectly) count the
387 * initial SYN frame in their delayed-ACK and congestion control
388 * algorithms that we must have the following bandaid to talk
389 * efficiently to them. -DaveM
391 tp->snd_cwnd = TCP_INIT_CWND;
393 /* See draft-stevens-tcpca-spec-01 for discussion of the
394 * initialization of these values.
396 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
397 tp->snd_cwnd_clamp = ~0;
398 tp->mss_cache = TCP_MSS_DEFAULT;
400 tp->reordering = sysctl_tcp_reordering;
401 tcp_enable_early_retrans(tp);
402 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
406 sk->sk_state = TCP_CLOSE;
408 sk->sk_write_space = sk_stream_write_space;
409 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
411 icsk->icsk_sync_mss = tcp_sync_mss;
413 /* Presumed zeroed, in order of appearance:
414 * cookie_in_always, cookie_out_never,
415 * s_data_constant, s_data_in, s_data_out
417 sk->sk_sndbuf = sysctl_tcp_wmem[1];
418 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
421 sock_update_memcg(sk);
422 sk_sockets_allocated_inc(sk);
425 EXPORT_SYMBOL(tcp_init_sock);
428 * Wait for a TCP event.
430 * Note that we don't need to lock the socket, as the upper poll layers
431 * take care of normal races (between the test and the event) and we don't
432 * go look at any of the socket buffers directly.
434 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
437 struct sock *sk = sock->sk;
438 const struct tcp_sock *tp = tcp_sk(sk);
440 sock_rps_record_flow(sk);
442 sock_poll_wait(file, sk_sleep(sk), wait);
443 if (sk->sk_state == TCP_LISTEN)
444 return inet_csk_listen_poll(sk);
446 /* Socket is not locked. We are protected from async events
447 * by poll logic and correct handling of state changes
448 * made by other threads is impossible in any case.
454 * POLLHUP is certainly not done right. But poll() doesn't
455 * have a notion of HUP in just one direction, and for a
456 * socket the read side is more interesting.
458 * Some poll() documentation says that POLLHUP is incompatible
459 * with the POLLOUT/POLLWR flags, so somebody should check this
460 * all. But careful, it tends to be safer to return too many
461 * bits than too few, and you can easily break real applications
462 * if you don't tell them that something has hung up!
466 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
467 * our fs/select.c). It means that after we received EOF,
468 * poll always returns immediately, making impossible poll() on write()
469 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
470 * if and only if shutdown has been made in both directions.
471 * Actually, it is interesting to look how Solaris and DUX
472 * solve this dilemma. I would prefer, if POLLHUP were maskable,
473 * then we could set it on SND_SHUTDOWN. BTW examples given
474 * in Stevens' books assume exactly this behaviour, it explains
475 * why POLLHUP is incompatible with POLLOUT. --ANK
477 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
478 * blocking on fresh not-connected or disconnected socket. --ANK
480 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
482 if (sk->sk_shutdown & RCV_SHUTDOWN)
483 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
485 /* Connected or passive Fast Open socket? */
486 if (sk->sk_state != TCP_SYN_SENT &&
487 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
488 int target = sock_rcvlowat(sk, 0, INT_MAX);
490 if (tp->urg_seq == tp->copied_seq &&
491 !sock_flag(sk, SOCK_URGINLINE) &&
495 /* Potential race condition. If read of tp below will
496 * escape above sk->sk_state, we can be illegally awaken
497 * in SYN_* states. */
498 if (tp->rcv_nxt - tp->copied_seq >= target)
499 mask |= POLLIN | POLLRDNORM;
501 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
502 if (sk_stream_is_writeable(sk)) {
503 mask |= POLLOUT | POLLWRNORM;
504 } else { /* send SIGIO later */
505 set_bit(SOCK_ASYNC_NOSPACE,
506 &sk->sk_socket->flags);
507 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
509 /* Race breaker. If space is freed after
510 * wspace test but before the flags are set,
511 * IO signal will be lost.
513 if (sk_stream_is_writeable(sk))
514 mask |= POLLOUT | POLLWRNORM;
517 mask |= POLLOUT | POLLWRNORM;
519 if (tp->urg_data & TCP_URG_VALID)
522 /* This barrier is coupled with smp_wmb() in tcp_reset() */
529 EXPORT_SYMBOL(tcp_poll);
531 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
533 struct tcp_sock *tp = tcp_sk(sk);
539 if (sk->sk_state == TCP_LISTEN)
542 slow = lock_sock_fast(sk);
543 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
545 else if (sock_flag(sk, SOCK_URGINLINE) ||
547 before(tp->urg_seq, tp->copied_seq) ||
548 !before(tp->urg_seq, tp->rcv_nxt)) {
550 answ = tp->rcv_nxt - tp->copied_seq;
552 /* Subtract 1, if FIN was received */
553 if (answ && sock_flag(sk, SOCK_DONE))
556 answ = tp->urg_seq - tp->copied_seq;
557 unlock_sock_fast(sk, slow);
560 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
563 if (sk->sk_state == TCP_LISTEN)
566 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
569 answ = tp->write_seq - tp->snd_una;
572 if (sk->sk_state == TCP_LISTEN)
575 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
578 answ = tp->write_seq - tp->snd_nxt;
584 return put_user(answ, (int __user *)arg);
586 EXPORT_SYMBOL(tcp_ioctl);
588 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
590 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
591 tp->pushed_seq = tp->write_seq;
594 static inline bool forced_push(const struct tcp_sock *tp)
596 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
599 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
601 struct tcp_sock *tp = tcp_sk(sk);
602 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
605 tcb->seq = tcb->end_seq = tp->write_seq;
606 tcb->tcp_flags = TCPHDR_ACK;
608 skb_header_release(skb);
609 tcp_add_write_queue_tail(sk, skb);
610 sk->sk_wmem_queued += skb->truesize;
611 sk_mem_charge(sk, skb->truesize);
612 if (tp->nonagle & TCP_NAGLE_PUSH)
613 tp->nonagle &= ~TCP_NAGLE_PUSH;
616 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
619 tp->snd_up = tp->write_seq;
622 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
625 if (tcp_send_head(sk)) {
626 struct tcp_sock *tp = tcp_sk(sk);
628 if (!(flags & MSG_MORE) || forced_push(tp))
629 tcp_mark_push(tp, tcp_write_queue_tail(sk));
631 tcp_mark_urg(tp, flags);
632 __tcp_push_pending_frames(sk, mss_now,
633 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
637 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
638 unsigned int offset, size_t len)
640 struct tcp_splice_state *tss = rd_desc->arg.data;
643 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
646 rd_desc->count -= ret;
650 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
652 /* Store TCP splice context information in read_descriptor_t. */
653 read_descriptor_t rd_desc = {
658 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
662 * tcp_splice_read - splice data from TCP socket to a pipe
663 * @sock: socket to splice from
664 * @ppos: position (not valid)
665 * @pipe: pipe to splice to
666 * @len: number of bytes to splice
667 * @flags: splice modifier flags
670 * Will read pages from given socket and fill them into a pipe.
673 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
674 struct pipe_inode_info *pipe, size_t len,
677 struct sock *sk = sock->sk;
678 struct tcp_splice_state tss = {
687 sock_rps_record_flow(sk);
689 * We can't seek on a socket input
698 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
700 ret = __tcp_splice_read(sk, &tss);
706 if (sock_flag(sk, SOCK_DONE))
709 ret = sock_error(sk);
712 if (sk->sk_shutdown & RCV_SHUTDOWN)
714 if (sk->sk_state == TCP_CLOSE) {
716 * This occurs when user tries to read
717 * from never connected socket.
719 if (!sock_flag(sk, SOCK_DONE))
727 sk_wait_data(sk, &timeo);
728 if (signal_pending(current)) {
729 ret = sock_intr_errno(timeo);
742 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
743 (sk->sk_shutdown & RCV_SHUTDOWN) ||
744 signal_pending(current))
755 EXPORT_SYMBOL(tcp_splice_read);
757 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
761 /* The TCP header must be at least 32-bit aligned. */
762 size = ALIGN(size, 4);
764 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
766 if (sk_wmem_schedule(sk, skb->truesize)) {
767 skb_reserve(skb, sk->sk_prot->max_header);
769 * Make sure that we have exactly size bytes
770 * available to the caller, no more, no less.
772 skb->reserved_tailroom = skb->end - skb->tail - size;
777 sk->sk_prot->enter_memory_pressure(sk);
778 sk_stream_moderate_sndbuf(sk);
783 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
786 struct tcp_sock *tp = tcp_sk(sk);
787 u32 xmit_size_goal, old_size_goal;
789 xmit_size_goal = mss_now;
791 if (large_allowed && sk_can_gso(sk)) {
792 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
793 inet_csk(sk)->icsk_af_ops->net_header_len -
794 inet_csk(sk)->icsk_ext_hdr_len -
797 /* TSQ : try to have two TSO segments in flight */
798 xmit_size_goal = min_t(u32, xmit_size_goal,
799 sysctl_tcp_limit_output_bytes >> 1);
801 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
803 /* We try hard to avoid divides here */
804 old_size_goal = tp->xmit_size_goal_segs * mss_now;
806 if (likely(old_size_goal <= xmit_size_goal &&
807 old_size_goal + mss_now > xmit_size_goal)) {
808 xmit_size_goal = old_size_goal;
810 tp->xmit_size_goal_segs =
811 min_t(u16, xmit_size_goal / mss_now,
812 sk->sk_gso_max_segs);
813 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
817 return max(xmit_size_goal, mss_now);
820 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
824 mss_now = tcp_current_mss(sk);
825 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
830 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
831 size_t size, int flags)
833 struct tcp_sock *tp = tcp_sk(sk);
834 int mss_now, size_goal;
837 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
839 /* Wait for a connection to finish. One exception is TCP Fast Open
840 * (passive side) where data is allowed to be sent before a connection
841 * is fully established.
843 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
844 !tcp_passive_fastopen(sk)) {
845 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
849 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
851 mss_now = tcp_send_mss(sk, &size_goal, flags);
855 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
859 struct sk_buff *skb = tcp_write_queue_tail(sk);
863 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
865 if (!sk_stream_memory_free(sk))
866 goto wait_for_sndbuf;
868 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
870 goto wait_for_memory;
879 i = skb_shinfo(skb)->nr_frags;
880 can_coalesce = skb_can_coalesce(skb, i, page, offset);
881 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
882 tcp_mark_push(tp, skb);
885 if (!sk_wmem_schedule(sk, copy))
886 goto wait_for_memory;
889 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
892 skb_fill_page_desc(skb, i, page, offset, copy);
894 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
897 skb->data_len += copy;
898 skb->truesize += copy;
899 sk->sk_wmem_queued += copy;
900 sk_mem_charge(sk, copy);
901 skb->ip_summed = CHECKSUM_PARTIAL;
902 tp->write_seq += copy;
903 TCP_SKB_CB(skb)->end_seq += copy;
904 skb_shinfo(skb)->gso_segs = 0;
907 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
914 if (skb->len < size_goal || (flags & MSG_OOB))
917 if (forced_push(tp)) {
918 tcp_mark_push(tp, skb);
919 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
920 } else if (skb == tcp_send_head(sk))
921 tcp_push_one(sk, mss_now);
925 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
927 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
929 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
932 mss_now = tcp_send_mss(sk, &size_goal, flags);
936 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
937 tcp_push(sk, flags, mss_now, tp->nonagle);
944 return sk_stream_error(sk, flags, err);
947 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
948 size_t size, int flags)
952 if (!(sk->sk_route_caps & NETIF_F_SG) ||
953 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
954 return sock_no_sendpage(sk->sk_socket, page, offset, size,
958 res = do_tcp_sendpages(sk, page, offset, size, flags);
962 EXPORT_SYMBOL(tcp_sendpage);
964 static inline int select_size(const struct sock *sk, bool sg)
966 const struct tcp_sock *tp = tcp_sk(sk);
967 int tmp = tp->mss_cache;
970 if (sk_can_gso(sk)) {
971 /* Small frames wont use a full page:
972 * Payload will immediately follow tcp header.
974 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
976 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
978 if (tmp >= pgbreak &&
979 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
987 void tcp_free_fastopen_req(struct tcp_sock *tp)
989 if (tp->fastopen_req != NULL) {
990 kfree(tp->fastopen_req);
991 tp->fastopen_req = NULL;
995 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size)
997 struct tcp_sock *tp = tcp_sk(sk);
1000 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1002 if (tp->fastopen_req != NULL)
1003 return -EALREADY; /* Another Fast Open is in progress */
1005 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1007 if (unlikely(tp->fastopen_req == NULL))
1009 tp->fastopen_req->data = msg;
1011 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1012 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1013 msg->msg_namelen, flags);
1014 *size = tp->fastopen_req->copied;
1015 tcp_free_fastopen_req(tp);
1019 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1023 struct tcp_sock *tp = tcp_sk(sk);
1024 struct sk_buff *skb;
1025 int iovlen, flags, err, copied = 0;
1026 int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1032 flags = msg->msg_flags;
1033 if (flags & MSG_FASTOPEN) {
1034 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn);
1035 if (err == -EINPROGRESS && copied_syn > 0)
1039 offset = copied_syn;
1042 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1044 /* Wait for a connection to finish. One exception is TCP Fast Open
1045 * (passive side) where data is allowed to be sent before a connection
1046 * is fully established.
1048 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1049 !tcp_passive_fastopen(sk)) {
1050 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1054 if (unlikely(tp->repair)) {
1055 if (tp->repair_queue == TCP_RECV_QUEUE) {
1056 copied = tcp_send_rcvq(sk, msg, size);
1061 if (tp->repair_queue == TCP_NO_QUEUE)
1064 /* 'common' sending to sendq */
1067 /* This should be in poll */
1068 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1070 mss_now = tcp_send_mss(sk, &size_goal, flags);
1072 /* Ok commence sending. */
1073 iovlen = msg->msg_iovlen;
1078 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1081 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1083 while (--iovlen >= 0) {
1084 size_t seglen = iov->iov_len;
1085 unsigned char __user *from = iov->iov_base;
1088 if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */
1089 if (offset >= seglen) {
1098 while (seglen > 0) {
1100 int max = size_goal;
1102 skb = tcp_write_queue_tail(sk);
1103 if (tcp_send_head(sk)) {
1104 if (skb->ip_summed == CHECKSUM_NONE)
1106 copy = max - skb->len;
1111 /* Allocate new segment. If the interface is SG,
1112 * allocate skb fitting to single page.
1114 if (!sk_stream_memory_free(sk))
1115 goto wait_for_sndbuf;
1117 skb = sk_stream_alloc_skb(sk,
1118 select_size(sk, sg),
1121 goto wait_for_memory;
1124 * Check whether we can use HW checksum.
1126 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1127 skb->ip_summed = CHECKSUM_PARTIAL;
1129 skb_entail(sk, skb);
1134 /* Try to append data to the end of skb. */
1138 /* Where to copy to? */
1139 if (skb_availroom(skb) > 0) {
1140 /* We have some space in skb head. Superb! */
1141 copy = min_t(int, copy, skb_availroom(skb));
1142 err = skb_add_data_nocache(sk, skb, from, copy);
1147 int i = skb_shinfo(skb)->nr_frags;
1148 struct page_frag *pfrag = sk_page_frag(sk);
1150 if (!sk_page_frag_refill(sk, pfrag))
1151 goto wait_for_memory;
1153 if (!skb_can_coalesce(skb, i, pfrag->page,
1155 if (i == MAX_SKB_FRAGS || !sg) {
1156 tcp_mark_push(tp, skb);
1162 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1164 if (!sk_wmem_schedule(sk, copy))
1165 goto wait_for_memory;
1167 err = skb_copy_to_page_nocache(sk, from, skb,
1174 /* Update the skb. */
1176 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1178 skb_fill_page_desc(skb, i, pfrag->page,
1179 pfrag->offset, copy);
1180 get_page(pfrag->page);
1182 pfrag->offset += copy;
1186 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1188 tp->write_seq += copy;
1189 TCP_SKB_CB(skb)->end_seq += copy;
1190 skb_shinfo(skb)->gso_segs = 0;
1194 if ((seglen -= copy) == 0 && iovlen == 0)
1197 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1200 if (forced_push(tp)) {
1201 tcp_mark_push(tp, skb);
1202 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1203 } else if (skb == tcp_send_head(sk))
1204 tcp_push_one(sk, mss_now);
1208 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1211 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1213 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1216 mss_now = tcp_send_mss(sk, &size_goal, flags);
1222 tcp_push(sk, flags, mss_now, tp->nonagle);
1224 return copied + copied_syn;
1228 tcp_unlink_write_queue(skb, sk);
1229 /* It is the one place in all of TCP, except connection
1230 * reset, where we can be unlinking the send_head.
1232 tcp_check_send_head(sk, skb);
1233 sk_wmem_free_skb(sk, skb);
1237 if (copied + copied_syn)
1240 err = sk_stream_error(sk, flags, err);
1244 EXPORT_SYMBOL(tcp_sendmsg);
1247 * Handle reading urgent data. BSD has very simple semantics for
1248 * this, no blocking and very strange errors 8)
1251 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1253 struct tcp_sock *tp = tcp_sk(sk);
1255 /* No URG data to read. */
1256 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1257 tp->urg_data == TCP_URG_READ)
1258 return -EINVAL; /* Yes this is right ! */
1260 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1263 if (tp->urg_data & TCP_URG_VALID) {
1265 char c = tp->urg_data;
1267 if (!(flags & MSG_PEEK))
1268 tp->urg_data = TCP_URG_READ;
1270 /* Read urgent data. */
1271 msg->msg_flags |= MSG_OOB;
1274 if (!(flags & MSG_TRUNC))
1275 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1278 msg->msg_flags |= MSG_TRUNC;
1280 return err ? -EFAULT : len;
1283 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1286 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1287 * the available implementations agree in this case:
1288 * this call should never block, independent of the
1289 * blocking state of the socket.
1290 * Mike <pall@rz.uni-karlsruhe.de>
1295 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1297 struct sk_buff *skb;
1298 int copied = 0, err = 0;
1300 /* XXX -- need to support SO_PEEK_OFF */
1302 skb_queue_walk(&sk->sk_write_queue, skb) {
1303 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
1310 return err ?: copied;
1313 /* Clean up the receive buffer for full frames taken by the user,
1314 * then send an ACK if necessary. COPIED is the number of bytes
1315 * tcp_recvmsg has given to the user so far, it speeds up the
1316 * calculation of whether or not we must ACK for the sake of
1319 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1321 struct tcp_sock *tp = tcp_sk(sk);
1322 bool time_to_ack = false;
1324 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1326 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1327 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1328 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1330 if (inet_csk_ack_scheduled(sk)) {
1331 const struct inet_connection_sock *icsk = inet_csk(sk);
1332 /* Delayed ACKs frequently hit locked sockets during bulk
1334 if (icsk->icsk_ack.blocked ||
1335 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1336 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1338 * If this read emptied read buffer, we send ACK, if
1339 * connection is not bidirectional, user drained
1340 * receive buffer and there was a small segment
1344 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1345 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1346 !icsk->icsk_ack.pingpong)) &&
1347 !atomic_read(&sk->sk_rmem_alloc)))
1351 /* We send an ACK if we can now advertise a non-zero window
1352 * which has been raised "significantly".
1354 * Even if window raised up to infinity, do not send window open ACK
1355 * in states, where we will not receive more. It is useless.
1357 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1358 __u32 rcv_window_now = tcp_receive_window(tp);
1360 /* Optimize, __tcp_select_window() is not cheap. */
1361 if (2*rcv_window_now <= tp->window_clamp) {
1362 __u32 new_window = __tcp_select_window(sk);
1364 /* Send ACK now, if this read freed lots of space
1365 * in our buffer. Certainly, new_window is new window.
1366 * We can advertise it now, if it is not less than current one.
1367 * "Lots" means "at least twice" here.
1369 if (new_window && new_window >= 2 * rcv_window_now)
1377 static void tcp_prequeue_process(struct sock *sk)
1379 struct sk_buff *skb;
1380 struct tcp_sock *tp = tcp_sk(sk);
1382 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1384 /* RX process wants to run with disabled BHs, though it is not
1387 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1388 sk_backlog_rcv(sk, skb);
1391 /* Clear memory counter. */
1392 tp->ucopy.memory = 0;
1395 #ifdef CONFIG_NET_DMA
1396 static void tcp_service_net_dma(struct sock *sk, bool wait)
1398 dma_cookie_t done, used;
1399 dma_cookie_t last_issued;
1400 struct tcp_sock *tp = tcp_sk(sk);
1402 if (!tp->ucopy.dma_chan)
1405 last_issued = tp->ucopy.dma_cookie;
1406 dma_async_issue_pending(tp->ucopy.dma_chan);
1409 if (dma_async_is_tx_complete(tp->ucopy.dma_chan,
1411 &used) == DMA_SUCCESS) {
1412 /* Safe to free early-copied skbs now */
1413 __skb_queue_purge(&sk->sk_async_wait_queue);
1416 struct sk_buff *skb;
1417 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1418 (dma_async_is_complete(skb->dma_cookie, done,
1419 used) == DMA_SUCCESS)) {
1420 __skb_dequeue(&sk->sk_async_wait_queue);
1428 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1430 struct sk_buff *skb;
1433 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1434 offset = seq - TCP_SKB_CB(skb)->seq;
1435 if (tcp_hdr(skb)->syn)
1437 if (offset < skb->len || tcp_hdr(skb)->fin) {
1441 /* This looks weird, but this can happen if TCP collapsing
1442 * splitted a fat GRO packet, while we released socket lock
1443 * in skb_splice_bits()
1445 sk_eat_skb(sk, skb, false);
1451 * This routine provides an alternative to tcp_recvmsg() for routines
1452 * that would like to handle copying from skbuffs directly in 'sendfile'
1455 * - It is assumed that the socket was locked by the caller.
1456 * - The routine does not block.
1457 * - At present, there is no support for reading OOB data
1458 * or for 'peeking' the socket using this routine
1459 * (although both would be easy to implement).
1461 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1462 sk_read_actor_t recv_actor)
1464 struct sk_buff *skb;
1465 struct tcp_sock *tp = tcp_sk(sk);
1466 u32 seq = tp->copied_seq;
1470 if (sk->sk_state == TCP_LISTEN)
1472 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1473 if (offset < skb->len) {
1477 len = skb->len - offset;
1478 /* Stop reading if we hit a patch of urgent data */
1480 u32 urg_offset = tp->urg_seq - seq;
1481 if (urg_offset < len)
1486 used = recv_actor(desc, skb, offset, len);
1491 } else if (used <= len) {
1496 /* If recv_actor drops the lock (e.g. TCP splice
1497 * receive) the skb pointer might be invalid when
1498 * getting here: tcp_collapse might have deleted it
1499 * while aggregating skbs from the socket queue.
1501 skb = tcp_recv_skb(sk, seq - 1, &offset);
1504 /* TCP coalescing might have appended data to the skb.
1505 * Try to splice more frags
1507 if (offset + 1 != skb->len)
1510 if (tcp_hdr(skb)->fin) {
1511 sk_eat_skb(sk, skb, false);
1515 sk_eat_skb(sk, skb, false);
1518 tp->copied_seq = seq;
1520 tp->copied_seq = seq;
1522 tcp_rcv_space_adjust(sk);
1524 /* Clean up data we have read: This will do ACK frames. */
1526 tcp_recv_skb(sk, seq, &offset);
1527 tcp_cleanup_rbuf(sk, copied);
1531 EXPORT_SYMBOL(tcp_read_sock);
1534 * This routine copies from a sock struct into the user buffer.
1536 * Technical note: in 2.3 we work on _locked_ socket, so that
1537 * tricks with *seq access order and skb->users are not required.
1538 * Probably, code can be easily improved even more.
1541 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1542 size_t len, int nonblock, int flags, int *addr_len)
1544 struct tcp_sock *tp = tcp_sk(sk);
1550 int target; /* Read at least this many bytes */
1552 struct task_struct *user_recv = NULL;
1553 bool copied_early = false;
1554 struct sk_buff *skb;
1557 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1558 (sk->sk_state == TCP_ESTABLISHED))
1559 sk_busy_loop(sk, nonblock);
1564 if (sk->sk_state == TCP_LISTEN)
1567 timeo = sock_rcvtimeo(sk, nonblock);
1569 /* Urgent data needs to be handled specially. */
1570 if (flags & MSG_OOB)
1573 if (unlikely(tp->repair)) {
1575 if (!(flags & MSG_PEEK))
1578 if (tp->repair_queue == TCP_SEND_QUEUE)
1582 if (tp->repair_queue == TCP_NO_QUEUE)
1585 /* 'common' recv queue MSG_PEEK-ing */
1588 seq = &tp->copied_seq;
1589 if (flags & MSG_PEEK) {
1590 peek_seq = tp->copied_seq;
1594 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1596 #ifdef CONFIG_NET_DMA
1597 tp->ucopy.dma_chan = NULL;
1599 skb = skb_peek_tail(&sk->sk_receive_queue);
1604 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1605 if ((available < target) &&
1606 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1607 !sysctl_tcp_low_latency &&
1608 net_dma_find_channel()) {
1609 preempt_enable_no_resched();
1610 tp->ucopy.pinned_list =
1611 dma_pin_iovec_pages(msg->msg_iov, len);
1613 preempt_enable_no_resched();
1621 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1622 if (tp->urg_data && tp->urg_seq == *seq) {
1625 if (signal_pending(current)) {
1626 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1631 /* Next get a buffer. */
1633 skb_queue_walk(&sk->sk_receive_queue, skb) {
1634 /* Now that we have two receive queues this
1637 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1638 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1639 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1643 offset = *seq - TCP_SKB_CB(skb)->seq;
1644 if (tcp_hdr(skb)->syn)
1646 if (offset < skb->len)
1648 if (tcp_hdr(skb)->fin)
1650 WARN(!(flags & MSG_PEEK),
1651 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1652 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1655 /* Well, if we have backlog, try to process it now yet. */
1657 if (copied >= target && !sk->sk_backlog.tail)
1662 sk->sk_state == TCP_CLOSE ||
1663 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1665 signal_pending(current))
1668 if (sock_flag(sk, SOCK_DONE))
1672 copied = sock_error(sk);
1676 if (sk->sk_shutdown & RCV_SHUTDOWN)
1679 if (sk->sk_state == TCP_CLOSE) {
1680 if (!sock_flag(sk, SOCK_DONE)) {
1681 /* This occurs when user tries to read
1682 * from never connected socket.
1695 if (signal_pending(current)) {
1696 copied = sock_intr_errno(timeo);
1701 tcp_cleanup_rbuf(sk, copied);
1703 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1704 /* Install new reader */
1705 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1706 user_recv = current;
1707 tp->ucopy.task = user_recv;
1708 tp->ucopy.iov = msg->msg_iov;
1711 tp->ucopy.len = len;
1713 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1714 !(flags & (MSG_PEEK | MSG_TRUNC)));
1716 /* Ugly... If prequeue is not empty, we have to
1717 * process it before releasing socket, otherwise
1718 * order will be broken at second iteration.
1719 * More elegant solution is required!!!
1721 * Look: we have the following (pseudo)queues:
1723 * 1. packets in flight
1728 * Each queue can be processed only if the next ones
1729 * are empty. At this point we have empty receive_queue.
1730 * But prequeue _can_ be not empty after 2nd iteration,
1731 * when we jumped to start of loop because backlog
1732 * processing added something to receive_queue.
1733 * We cannot release_sock(), because backlog contains
1734 * packets arrived _after_ prequeued ones.
1736 * Shortly, algorithm is clear --- to process all
1737 * the queues in order. We could make it more directly,
1738 * requeueing packets from backlog to prequeue, if
1739 * is not empty. It is more elegant, but eats cycles,
1742 if (!skb_queue_empty(&tp->ucopy.prequeue))
1745 /* __ Set realtime policy in scheduler __ */
1748 #ifdef CONFIG_NET_DMA
1749 if (tp->ucopy.dma_chan) {
1750 if (tp->rcv_wnd == 0 &&
1751 !skb_queue_empty(&sk->sk_async_wait_queue)) {
1752 tcp_service_net_dma(sk, true);
1753 tcp_cleanup_rbuf(sk, copied);
1755 dma_async_issue_pending(tp->ucopy.dma_chan);
1758 if (copied >= target) {
1759 /* Do not sleep, just process backlog. */
1763 sk_wait_data(sk, &timeo);
1765 #ifdef CONFIG_NET_DMA
1766 tcp_service_net_dma(sk, false); /* Don't block */
1767 tp->ucopy.wakeup = 0;
1773 /* __ Restore normal policy in scheduler __ */
1775 if ((chunk = len - tp->ucopy.len) != 0) {
1776 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1781 if (tp->rcv_nxt == tp->copied_seq &&
1782 !skb_queue_empty(&tp->ucopy.prequeue)) {
1784 tcp_prequeue_process(sk);
1786 if ((chunk = len - tp->ucopy.len) != 0) {
1787 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1793 if ((flags & MSG_PEEK) &&
1794 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1795 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1797 task_pid_nr(current));
1798 peek_seq = tp->copied_seq;
1803 /* Ok so how much can we use? */
1804 used = skb->len - offset;
1808 /* Do we have urgent data here? */
1810 u32 urg_offset = tp->urg_seq - *seq;
1811 if (urg_offset < used) {
1813 if (!sock_flag(sk, SOCK_URGINLINE)) {
1826 if (!(flags & MSG_TRUNC)) {
1827 #ifdef CONFIG_NET_DMA
1828 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1829 tp->ucopy.dma_chan = net_dma_find_channel();
1831 if (tp->ucopy.dma_chan) {
1832 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1833 tp->ucopy.dma_chan, skb, offset,
1835 tp->ucopy.pinned_list);
1837 if (tp->ucopy.dma_cookie < 0) {
1839 pr_alert("%s: dma_cookie < 0\n",
1842 /* Exception. Bailout! */
1848 dma_async_issue_pending(tp->ucopy.dma_chan);
1850 if ((offset + used) == skb->len)
1851 copied_early = true;
1856 err = skb_copy_datagram_iovec(skb, offset,
1857 msg->msg_iov, used);
1859 /* Exception. Bailout! */
1871 tcp_rcv_space_adjust(sk);
1874 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1876 tcp_fast_path_check(sk);
1878 if (used + offset < skb->len)
1881 if (tcp_hdr(skb)->fin)
1883 if (!(flags & MSG_PEEK)) {
1884 sk_eat_skb(sk, skb, copied_early);
1885 copied_early = false;
1890 /* Process the FIN. */
1892 if (!(flags & MSG_PEEK)) {
1893 sk_eat_skb(sk, skb, copied_early);
1894 copied_early = false;
1900 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1903 tp->ucopy.len = copied > 0 ? len : 0;
1905 tcp_prequeue_process(sk);
1907 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1908 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1914 tp->ucopy.task = NULL;
1918 #ifdef CONFIG_NET_DMA
1919 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1920 tp->ucopy.dma_chan = NULL;
1922 if (tp->ucopy.pinned_list) {
1923 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1924 tp->ucopy.pinned_list = NULL;
1928 /* According to UNIX98, msg_name/msg_namelen are ignored
1929 * on connected socket. I was just happy when found this 8) --ANK
1932 /* Clean up data we have read: This will do ACK frames. */
1933 tcp_cleanup_rbuf(sk, copied);
1943 err = tcp_recv_urg(sk, msg, len, flags);
1947 err = tcp_peek_sndq(sk, msg, len);
1950 EXPORT_SYMBOL(tcp_recvmsg);
1952 void tcp_set_state(struct sock *sk, int state)
1954 int oldstate = sk->sk_state;
1957 case TCP_ESTABLISHED:
1958 if (oldstate != TCP_ESTABLISHED)
1959 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1963 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1964 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1966 sk->sk_prot->unhash(sk);
1967 if (inet_csk(sk)->icsk_bind_hash &&
1968 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1972 if (oldstate == TCP_ESTABLISHED)
1973 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1976 /* Change state AFTER socket is unhashed to avoid closed
1977 * socket sitting in hash tables.
1979 sk->sk_state = state;
1982 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1985 EXPORT_SYMBOL_GPL(tcp_set_state);
1988 * State processing on a close. This implements the state shift for
1989 * sending our FIN frame. Note that we only send a FIN for some
1990 * states. A shutdown() may have already sent the FIN, or we may be
1994 static const unsigned char new_state[16] = {
1995 /* current state: new state: action: */
1996 /* (Invalid) */ TCP_CLOSE,
1997 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1998 /* TCP_SYN_SENT */ TCP_CLOSE,
1999 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2000 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
2001 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
2002 /* TCP_TIME_WAIT */ TCP_CLOSE,
2003 /* TCP_CLOSE */ TCP_CLOSE,
2004 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
2005 /* TCP_LAST_ACK */ TCP_LAST_ACK,
2006 /* TCP_LISTEN */ TCP_CLOSE,
2007 /* TCP_CLOSING */ TCP_CLOSING,
2010 static int tcp_close_state(struct sock *sk)
2012 int next = (int)new_state[sk->sk_state];
2013 int ns = next & TCP_STATE_MASK;
2015 tcp_set_state(sk, ns);
2017 return next & TCP_ACTION_FIN;
2021 * Shutdown the sending side of a connection. Much like close except
2022 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2025 void tcp_shutdown(struct sock *sk, int how)
2027 /* We need to grab some memory, and put together a FIN,
2028 * and then put it into the queue to be sent.
2029 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2031 if (!(how & SEND_SHUTDOWN))
2034 /* If we've already sent a FIN, or it's a closed state, skip this. */
2035 if ((1 << sk->sk_state) &
2036 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2037 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2038 /* Clear out any half completed packets. FIN if needed. */
2039 if (tcp_close_state(sk))
2043 EXPORT_SYMBOL(tcp_shutdown);
2045 bool tcp_check_oom(struct sock *sk, int shift)
2047 bool too_many_orphans, out_of_socket_memory;
2049 too_many_orphans = tcp_too_many_orphans(sk, shift);
2050 out_of_socket_memory = tcp_out_of_memory(sk);
2052 if (too_many_orphans)
2053 net_info_ratelimited("too many orphaned sockets\n");
2054 if (out_of_socket_memory)
2055 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2056 return too_many_orphans || out_of_socket_memory;
2059 void tcp_close(struct sock *sk, long timeout)
2061 struct sk_buff *skb;
2062 int data_was_unread = 0;
2066 sk->sk_shutdown = SHUTDOWN_MASK;
2068 if (sk->sk_state == TCP_LISTEN) {
2069 tcp_set_state(sk, TCP_CLOSE);
2072 inet_csk_listen_stop(sk);
2074 goto adjudge_to_death;
2077 /* We need to flush the recv. buffs. We do this only on the
2078 * descriptor close, not protocol-sourced closes, because the
2079 * reader process may not have drained the data yet!
2081 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2082 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2084 data_was_unread += len;
2090 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2091 if (sk->sk_state == TCP_CLOSE)
2092 goto adjudge_to_death;
2094 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2095 * data was lost. To witness the awful effects of the old behavior of
2096 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2097 * GET in an FTP client, suspend the process, wait for the client to
2098 * advertise a zero window, then kill -9 the FTP client, wheee...
2099 * Note: timeout is always zero in such a case.
2101 if (unlikely(tcp_sk(sk)->repair)) {
2102 sk->sk_prot->disconnect(sk, 0);
2103 } else if (data_was_unread) {
2104 /* Unread data was tossed, zap the connection. */
2105 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2106 tcp_set_state(sk, TCP_CLOSE);
2107 tcp_send_active_reset(sk, sk->sk_allocation);
2108 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2109 /* Check zero linger _after_ checking for unread data. */
2110 sk->sk_prot->disconnect(sk, 0);
2111 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2112 } else if (tcp_close_state(sk)) {
2113 /* We FIN if the application ate all the data before
2114 * zapping the connection.
2117 /* RED-PEN. Formally speaking, we have broken TCP state
2118 * machine. State transitions:
2120 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2121 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2122 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2124 * are legal only when FIN has been sent (i.e. in window),
2125 * rather than queued out of window. Purists blame.
2127 * F.e. "RFC state" is ESTABLISHED,
2128 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2130 * The visible declinations are that sometimes
2131 * we enter time-wait state, when it is not required really
2132 * (harmless), do not send active resets, when they are
2133 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2134 * they look as CLOSING or LAST_ACK for Linux)
2135 * Probably, I missed some more holelets.
2137 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2138 * in a single packet! (May consider it later but will
2139 * probably need API support or TCP_CORK SYN-ACK until
2140 * data is written and socket is closed.)
2145 sk_stream_wait_close(sk, timeout);
2148 state = sk->sk_state;
2152 /* It is the last release_sock in its life. It will remove backlog. */
2156 /* Now socket is owned by kernel and we acquire BH lock
2157 to finish close. No need to check for user refs.
2161 WARN_ON(sock_owned_by_user(sk));
2163 percpu_counter_inc(sk->sk_prot->orphan_count);
2165 /* Have we already been destroyed by a softirq or backlog? */
2166 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2169 /* This is a (useful) BSD violating of the RFC. There is a
2170 * problem with TCP as specified in that the other end could
2171 * keep a socket open forever with no application left this end.
2172 * We use a 3 minute timeout (about the same as BSD) then kill
2173 * our end. If they send after that then tough - BUT: long enough
2174 * that we won't make the old 4*rto = almost no time - whoops
2177 * Nope, it was not mistake. It is really desired behaviour
2178 * f.e. on http servers, when such sockets are useless, but
2179 * consume significant resources. Let's do it with special
2180 * linger2 option. --ANK
2183 if (sk->sk_state == TCP_FIN_WAIT2) {
2184 struct tcp_sock *tp = tcp_sk(sk);
2185 if (tp->linger2 < 0) {
2186 tcp_set_state(sk, TCP_CLOSE);
2187 tcp_send_active_reset(sk, GFP_ATOMIC);
2188 NET_INC_STATS_BH(sock_net(sk),
2189 LINUX_MIB_TCPABORTONLINGER);
2191 const int tmo = tcp_fin_time(sk);
2193 if (tmo > TCP_TIMEWAIT_LEN) {
2194 inet_csk_reset_keepalive_timer(sk,
2195 tmo - TCP_TIMEWAIT_LEN);
2197 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2202 if (sk->sk_state != TCP_CLOSE) {
2204 if (tcp_check_oom(sk, 0)) {
2205 tcp_set_state(sk, TCP_CLOSE);
2206 tcp_send_active_reset(sk, GFP_ATOMIC);
2207 NET_INC_STATS_BH(sock_net(sk),
2208 LINUX_MIB_TCPABORTONMEMORY);
2212 if (sk->sk_state == TCP_CLOSE) {
2213 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2214 /* We could get here with a non-NULL req if the socket is
2215 * aborted (e.g., closed with unread data) before 3WHS
2219 reqsk_fastopen_remove(sk, req, false);
2220 inet_csk_destroy_sock(sk);
2222 /* Otherwise, socket is reprieved until protocol close. */
2229 EXPORT_SYMBOL(tcp_close);
2231 /* These states need RST on ABORT according to RFC793 */
2233 static inline bool tcp_need_reset(int state)
2235 return (1 << state) &
2236 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2237 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2240 int tcp_disconnect(struct sock *sk, int flags)
2242 struct inet_sock *inet = inet_sk(sk);
2243 struct inet_connection_sock *icsk = inet_csk(sk);
2244 struct tcp_sock *tp = tcp_sk(sk);
2246 int old_state = sk->sk_state;
2248 if (old_state != TCP_CLOSE)
2249 tcp_set_state(sk, TCP_CLOSE);
2251 /* ABORT function of RFC793 */
2252 if (old_state == TCP_LISTEN) {
2253 inet_csk_listen_stop(sk);
2254 } else if (unlikely(tp->repair)) {
2255 sk->sk_err = ECONNABORTED;
2256 } else if (tcp_need_reset(old_state) ||
2257 (tp->snd_nxt != tp->write_seq &&
2258 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2259 /* The last check adjusts for discrepancy of Linux wrt. RFC
2262 tcp_send_active_reset(sk, gfp_any());
2263 sk->sk_err = ECONNRESET;
2264 } else if (old_state == TCP_SYN_SENT)
2265 sk->sk_err = ECONNRESET;
2267 tcp_clear_xmit_timers(sk);
2268 __skb_queue_purge(&sk->sk_receive_queue);
2269 tcp_write_queue_purge(sk);
2270 __skb_queue_purge(&tp->out_of_order_queue);
2271 #ifdef CONFIG_NET_DMA
2272 __skb_queue_purge(&sk->sk_async_wait_queue);
2275 inet->inet_dport = 0;
2277 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2278 inet_reset_saddr(sk);
2280 sk->sk_shutdown = 0;
2281 sock_reset_flag(sk, SOCK_DONE);
2283 if ((tp->write_seq += tp->max_window + 2) == 0)
2285 icsk->icsk_backoff = 0;
2287 icsk->icsk_probes_out = 0;
2288 tp->packets_out = 0;
2289 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2290 tp->snd_cwnd_cnt = 0;
2291 tp->window_clamp = 0;
2292 tcp_set_ca_state(sk, TCP_CA_Open);
2293 tcp_clear_retrans(tp);
2294 inet_csk_delack_init(sk);
2295 tcp_init_send_head(sk);
2296 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2299 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2301 sk->sk_error_report(sk);
2304 EXPORT_SYMBOL(tcp_disconnect);
2306 void tcp_sock_destruct(struct sock *sk)
2308 inet_sock_destruct(sk);
2310 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2313 static inline bool tcp_can_repair_sock(const struct sock *sk)
2315 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2316 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2319 static int tcp_repair_options_est(struct tcp_sock *tp,
2320 struct tcp_repair_opt __user *optbuf, unsigned int len)
2322 struct tcp_repair_opt opt;
2324 while (len >= sizeof(opt)) {
2325 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2331 switch (opt.opt_code) {
2333 tp->rx_opt.mss_clamp = opt.opt_val;
2337 u16 snd_wscale = opt.opt_val & 0xFFFF;
2338 u16 rcv_wscale = opt.opt_val >> 16;
2340 if (snd_wscale > 14 || rcv_wscale > 14)
2343 tp->rx_opt.snd_wscale = snd_wscale;
2344 tp->rx_opt.rcv_wscale = rcv_wscale;
2345 tp->rx_opt.wscale_ok = 1;
2348 case TCPOPT_SACK_PERM:
2349 if (opt.opt_val != 0)
2352 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2353 if (sysctl_tcp_fack)
2354 tcp_enable_fack(tp);
2356 case TCPOPT_TIMESTAMP:
2357 if (opt.opt_val != 0)
2360 tp->rx_opt.tstamp_ok = 1;
2369 * Socket option code for TCP.
2371 static int do_tcp_setsockopt(struct sock *sk, int level,
2372 int optname, char __user *optval, unsigned int optlen)
2374 struct tcp_sock *tp = tcp_sk(sk);
2375 struct inet_connection_sock *icsk = inet_csk(sk);
2379 /* These are data/string values, all the others are ints */
2381 case TCP_CONGESTION: {
2382 char name[TCP_CA_NAME_MAX];
2387 val = strncpy_from_user(name, optval,
2388 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2394 err = tcp_set_congestion_control(sk, name);
2403 if (optlen < sizeof(int))
2406 if (get_user(val, (int __user *)optval))
2413 /* Values greater than interface MTU won't take effect. However
2414 * at the point when this call is done we typically don't yet
2415 * know which interface is going to be used */
2416 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2420 tp->rx_opt.user_mss = val;
2425 /* TCP_NODELAY is weaker than TCP_CORK, so that
2426 * this option on corked socket is remembered, but
2427 * it is not activated until cork is cleared.
2429 * However, when TCP_NODELAY is set we make
2430 * an explicit push, which overrides even TCP_CORK
2431 * for currently queued segments.
2433 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2434 tcp_push_pending_frames(sk);
2436 tp->nonagle &= ~TCP_NAGLE_OFF;
2440 case TCP_THIN_LINEAR_TIMEOUTS:
2441 if (val < 0 || val > 1)
2447 case TCP_THIN_DUPACK:
2448 if (val < 0 || val > 1)
2451 tp->thin_dupack = val;
2452 if (tp->thin_dupack)
2453 tcp_disable_early_retrans(tp);
2457 if (!tcp_can_repair_sock(sk))
2459 else if (val == 1) {
2461 sk->sk_reuse = SK_FORCE_REUSE;
2462 tp->repair_queue = TCP_NO_QUEUE;
2463 } else if (val == 0) {
2465 sk->sk_reuse = SK_NO_REUSE;
2466 tcp_send_window_probe(sk);
2472 case TCP_REPAIR_QUEUE:
2475 else if (val < TCP_QUEUES_NR)
2476 tp->repair_queue = val;
2482 if (sk->sk_state != TCP_CLOSE)
2484 else if (tp->repair_queue == TCP_SEND_QUEUE)
2485 tp->write_seq = val;
2486 else if (tp->repair_queue == TCP_RECV_QUEUE)
2492 case TCP_REPAIR_OPTIONS:
2495 else if (sk->sk_state == TCP_ESTABLISHED)
2496 err = tcp_repair_options_est(tp,
2497 (struct tcp_repair_opt __user *)optval,
2504 /* When set indicates to always queue non-full frames.
2505 * Later the user clears this option and we transmit
2506 * any pending partial frames in the queue. This is
2507 * meant to be used alongside sendfile() to get properly
2508 * filled frames when the user (for example) must write
2509 * out headers with a write() call first and then use
2510 * sendfile to send out the data parts.
2512 * TCP_CORK can be set together with TCP_NODELAY and it is
2513 * stronger than TCP_NODELAY.
2516 tp->nonagle |= TCP_NAGLE_CORK;
2518 tp->nonagle &= ~TCP_NAGLE_CORK;
2519 if (tp->nonagle&TCP_NAGLE_OFF)
2520 tp->nonagle |= TCP_NAGLE_PUSH;
2521 tcp_push_pending_frames(sk);
2526 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2529 tp->keepalive_time = val * HZ;
2530 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2531 !((1 << sk->sk_state) &
2532 (TCPF_CLOSE | TCPF_LISTEN))) {
2533 u32 elapsed = keepalive_time_elapsed(tp);
2534 if (tp->keepalive_time > elapsed)
2535 elapsed = tp->keepalive_time - elapsed;
2538 inet_csk_reset_keepalive_timer(sk, elapsed);
2543 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2546 tp->keepalive_intvl = val * HZ;
2549 if (val < 1 || val > MAX_TCP_KEEPCNT)
2552 tp->keepalive_probes = val;
2555 if (val < 1 || val > MAX_TCP_SYNCNT)
2558 icsk->icsk_syn_retries = val;
2564 else if (val > sysctl_tcp_fin_timeout / HZ)
2567 tp->linger2 = val * HZ;
2570 case TCP_DEFER_ACCEPT:
2571 /* Translate value in seconds to number of retransmits */
2572 icsk->icsk_accept_queue.rskq_defer_accept =
2573 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2577 case TCP_WINDOW_CLAMP:
2579 if (sk->sk_state != TCP_CLOSE) {
2583 tp->window_clamp = 0;
2585 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2586 SOCK_MIN_RCVBUF / 2 : val;
2591 icsk->icsk_ack.pingpong = 1;
2593 icsk->icsk_ack.pingpong = 0;
2594 if ((1 << sk->sk_state) &
2595 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2596 inet_csk_ack_scheduled(sk)) {
2597 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2598 tcp_cleanup_rbuf(sk, 1);
2600 icsk->icsk_ack.pingpong = 1;
2605 #ifdef CONFIG_TCP_MD5SIG
2607 /* Read the IP->Key mappings from userspace */
2608 err = tp->af_specific->md5_parse(sk, optval, optlen);
2611 case TCP_USER_TIMEOUT:
2612 /* Cap the max timeout in ms TCP will retry/retrans
2613 * before giving up and aborting (ETIMEDOUT) a connection.
2618 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2622 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2624 err = fastopen_init_queue(sk, val);
2632 tp->tsoffset = val - tcp_time_stamp;
2643 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2644 unsigned int optlen)
2646 const struct inet_connection_sock *icsk = inet_csk(sk);
2648 if (level != SOL_TCP)
2649 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2651 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2653 EXPORT_SYMBOL(tcp_setsockopt);
2655 #ifdef CONFIG_COMPAT
2656 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2657 char __user *optval, unsigned int optlen)
2659 if (level != SOL_TCP)
2660 return inet_csk_compat_setsockopt(sk, level, optname,
2662 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2664 EXPORT_SYMBOL(compat_tcp_setsockopt);
2667 /* Return information about state of tcp endpoint in API format. */
2668 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2670 const struct tcp_sock *tp = tcp_sk(sk);
2671 const struct inet_connection_sock *icsk = inet_csk(sk);
2672 u32 now = tcp_time_stamp;
2674 memset(info, 0, sizeof(*info));
2676 info->tcpi_state = sk->sk_state;
2677 info->tcpi_ca_state = icsk->icsk_ca_state;
2678 info->tcpi_retransmits = icsk->icsk_retransmits;
2679 info->tcpi_probes = icsk->icsk_probes_out;
2680 info->tcpi_backoff = icsk->icsk_backoff;
2682 if (tp->rx_opt.tstamp_ok)
2683 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2684 if (tcp_is_sack(tp))
2685 info->tcpi_options |= TCPI_OPT_SACK;
2686 if (tp->rx_opt.wscale_ok) {
2687 info->tcpi_options |= TCPI_OPT_WSCALE;
2688 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2689 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2692 if (tp->ecn_flags & TCP_ECN_OK)
2693 info->tcpi_options |= TCPI_OPT_ECN;
2694 if (tp->ecn_flags & TCP_ECN_SEEN)
2695 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2696 if (tp->syn_data_acked)
2697 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2699 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2700 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2701 info->tcpi_snd_mss = tp->mss_cache;
2702 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2704 if (sk->sk_state == TCP_LISTEN) {
2705 info->tcpi_unacked = sk->sk_ack_backlog;
2706 info->tcpi_sacked = sk->sk_max_ack_backlog;
2708 info->tcpi_unacked = tp->packets_out;
2709 info->tcpi_sacked = tp->sacked_out;
2711 info->tcpi_lost = tp->lost_out;
2712 info->tcpi_retrans = tp->retrans_out;
2713 info->tcpi_fackets = tp->fackets_out;
2715 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2716 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2717 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2719 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2720 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2721 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2722 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2723 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2724 info->tcpi_snd_cwnd = tp->snd_cwnd;
2725 info->tcpi_advmss = tp->advmss;
2726 info->tcpi_reordering = tp->reordering;
2728 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2729 info->tcpi_rcv_space = tp->rcvq_space.space;
2731 info->tcpi_total_retrans = tp->total_retrans;
2733 EXPORT_SYMBOL_GPL(tcp_get_info);
2735 static int do_tcp_getsockopt(struct sock *sk, int level,
2736 int optname, char __user *optval, int __user *optlen)
2738 struct inet_connection_sock *icsk = inet_csk(sk);
2739 struct tcp_sock *tp = tcp_sk(sk);
2742 if (get_user(len, optlen))
2745 len = min_t(unsigned int, len, sizeof(int));
2752 val = tp->mss_cache;
2753 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2754 val = tp->rx_opt.user_mss;
2756 val = tp->rx_opt.mss_clamp;
2759 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2762 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2765 val = keepalive_time_when(tp) / HZ;
2768 val = keepalive_intvl_when(tp) / HZ;
2771 val = keepalive_probes(tp);
2774 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2779 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2781 case TCP_DEFER_ACCEPT:
2782 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2783 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2785 case TCP_WINDOW_CLAMP:
2786 val = tp->window_clamp;
2789 struct tcp_info info;
2791 if (get_user(len, optlen))
2794 tcp_get_info(sk, &info);
2796 len = min_t(unsigned int, len, sizeof(info));
2797 if (put_user(len, optlen))
2799 if (copy_to_user(optval, &info, len))
2804 val = !icsk->icsk_ack.pingpong;
2807 case TCP_CONGESTION:
2808 if (get_user(len, optlen))
2810 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2811 if (put_user(len, optlen))
2813 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2817 case TCP_THIN_LINEAR_TIMEOUTS:
2820 case TCP_THIN_DUPACK:
2821 val = tp->thin_dupack;
2828 case TCP_REPAIR_QUEUE:
2830 val = tp->repair_queue;
2836 if (tp->repair_queue == TCP_SEND_QUEUE)
2837 val = tp->write_seq;
2838 else if (tp->repair_queue == TCP_RECV_QUEUE)
2844 case TCP_USER_TIMEOUT:
2845 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2848 val = tcp_time_stamp + tp->tsoffset;
2851 return -ENOPROTOOPT;
2854 if (put_user(len, optlen))
2856 if (copy_to_user(optval, &val, len))
2861 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2864 struct inet_connection_sock *icsk = inet_csk(sk);
2866 if (level != SOL_TCP)
2867 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2869 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2871 EXPORT_SYMBOL(tcp_getsockopt);
2873 #ifdef CONFIG_COMPAT
2874 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2875 char __user *optval, int __user *optlen)
2877 if (level != SOL_TCP)
2878 return inet_csk_compat_getsockopt(sk, level, optname,
2880 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2882 EXPORT_SYMBOL(compat_tcp_getsockopt);
2885 #ifdef CONFIG_TCP_MD5SIG
2886 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool __read_mostly;
2887 static DEFINE_MUTEX(tcp_md5sig_mutex);
2889 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
2893 for_each_possible_cpu(cpu) {
2894 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
2896 if (p->md5_desc.tfm)
2897 crypto_free_hash(p->md5_desc.tfm);
2902 static void __tcp_alloc_md5sig_pool(void)
2905 struct tcp_md5sig_pool __percpu *pool;
2907 pool = alloc_percpu(struct tcp_md5sig_pool);
2911 for_each_possible_cpu(cpu) {
2912 struct crypto_hash *hash;
2914 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2915 if (IS_ERR_OR_NULL(hash))
2918 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
2920 /* before setting tcp_md5sig_pool, we must commit all writes
2921 * to memory. See ACCESS_ONCE() in tcp_get_md5sig_pool()
2924 tcp_md5sig_pool = pool;
2927 __tcp_free_md5sig_pool(pool);
2930 bool tcp_alloc_md5sig_pool(void)
2932 if (unlikely(!tcp_md5sig_pool)) {
2933 mutex_lock(&tcp_md5sig_mutex);
2935 if (!tcp_md5sig_pool)
2936 __tcp_alloc_md5sig_pool();
2938 mutex_unlock(&tcp_md5sig_mutex);
2940 return tcp_md5sig_pool != NULL;
2942 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2946 * tcp_get_md5sig_pool - get md5sig_pool for this user
2948 * We use percpu structure, so if we succeed, we exit with preemption
2949 * and BH disabled, to make sure another thread or softirq handling
2950 * wont try to get same context.
2952 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2954 struct tcp_md5sig_pool __percpu *p;
2957 p = ACCESS_ONCE(tcp_md5sig_pool);
2959 return __this_cpu_ptr(p);
2964 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2966 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2967 const struct tcphdr *th)
2969 struct scatterlist sg;
2973 /* We are not allowed to change tcphdr, make a local copy */
2974 memcpy(&hdr, th, sizeof(hdr));
2977 /* options aren't included in the hash */
2978 sg_init_one(&sg, &hdr, sizeof(hdr));
2979 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2982 EXPORT_SYMBOL(tcp_md5_hash_header);
2984 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2985 const struct sk_buff *skb, unsigned int header_len)
2987 struct scatterlist sg;
2988 const struct tcphdr *tp = tcp_hdr(skb);
2989 struct hash_desc *desc = &hp->md5_desc;
2991 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
2992 skb_headlen(skb) - header_len : 0;
2993 const struct skb_shared_info *shi = skb_shinfo(skb);
2994 struct sk_buff *frag_iter;
2996 sg_init_table(&sg, 1);
2998 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2999 if (crypto_hash_update(desc, &sg, head_data_len))
3002 for (i = 0; i < shi->nr_frags; ++i) {
3003 const struct skb_frag_struct *f = &shi->frags[i];
3004 unsigned int offset = f->page_offset;
3005 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
3007 sg_set_page(&sg, page, skb_frag_size(f),
3008 offset_in_page(offset));
3009 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3013 skb_walk_frags(skb, frag_iter)
3014 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3019 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3021 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3023 struct scatterlist sg;
3025 sg_init_one(&sg, key->key, key->keylen);
3026 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3028 EXPORT_SYMBOL(tcp_md5_hash_key);
3032 void tcp_done(struct sock *sk)
3034 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
3036 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3037 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3039 tcp_set_state(sk, TCP_CLOSE);
3040 tcp_clear_xmit_timers(sk);
3042 reqsk_fastopen_remove(sk, req, false);
3044 sk->sk_shutdown = SHUTDOWN_MASK;
3046 if (!sock_flag(sk, SOCK_DEAD))
3047 sk->sk_state_change(sk);
3049 inet_csk_destroy_sock(sk);
3051 EXPORT_SYMBOL_GPL(tcp_done);
3053 extern struct tcp_congestion_ops tcp_reno;
3055 static __initdata unsigned long thash_entries;
3056 static int __init set_thash_entries(char *str)
3063 ret = kstrtoul(str, 0, &thash_entries);
3069 __setup("thash_entries=", set_thash_entries);
3071 void tcp_init_mem(struct net *net)
3073 unsigned long limit = nr_free_buffer_pages() / 8;
3074 limit = max(limit, 128UL);
3075 net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
3076 net->ipv4.sysctl_tcp_mem[1] = limit;
3077 net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
3080 void __init tcp_init(void)
3082 struct sk_buff *skb = NULL;
3083 unsigned long limit;
3084 int max_rshare, max_wshare, cnt;
3087 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3089 percpu_counter_init(&tcp_sockets_allocated, 0);
3090 percpu_counter_init(&tcp_orphan_count, 0);
3091 tcp_hashinfo.bind_bucket_cachep =
3092 kmem_cache_create("tcp_bind_bucket",
3093 sizeof(struct inet_bind_bucket), 0,
3094 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3096 /* Size and allocate the main established and bind bucket
3099 * The methodology is similar to that of the buffer cache.
3101 tcp_hashinfo.ehash =
3102 alloc_large_system_hash("TCP established",
3103 sizeof(struct inet_ehash_bucket),
3105 17, /* one slot per 128 KB of memory */
3108 &tcp_hashinfo.ehash_mask,
3110 thash_entries ? 0 : 512 * 1024);
3111 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3112 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3113 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3115 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3116 panic("TCP: failed to alloc ehash_locks");
3117 tcp_hashinfo.bhash =
3118 alloc_large_system_hash("TCP bind",
3119 sizeof(struct inet_bind_hashbucket),
3120 tcp_hashinfo.ehash_mask + 1,
3121 17, /* one slot per 128 KB of memory */
3123 &tcp_hashinfo.bhash_size,
3127 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3128 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3129 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3130 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3134 cnt = tcp_hashinfo.ehash_mask + 1;
3136 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3137 sysctl_tcp_max_orphans = cnt / 2;
3138 sysctl_max_syn_backlog = max(128, cnt / 256);
3140 tcp_init_mem(&init_net);
3141 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3142 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3143 max_wshare = min(4UL*1024*1024, limit);
3144 max_rshare = min(6UL*1024*1024, limit);
3146 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3147 sysctl_tcp_wmem[1] = 16*1024;
3148 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3150 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3151 sysctl_tcp_rmem[1] = 87380;
3152 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3154 pr_info("Hash tables configured (established %u bind %u)\n",
3155 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3159 tcp_register_congestion_control(&tcp_reno);