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 #include <linux/kernel.h>
249 #include <linux/module.h>
250 #include <linux/types.h>
251 #include <linux/fcntl.h>
252 #include <linux/poll.h>
253 #include <linux/init.h>
254 #include <linux/fs.h>
255 #include <linux/skbuff.h>
256 #include <linux/scatterlist.h>
257 #include <linux/splice.h>
258 #include <linux/net.h>
259 #include <linux/socket.h>
260 #include <linux/random.h>
261 #include <linux/bootmem.h>
262 #include <linux/highmem.h>
263 #include <linux/swap.h>
264 #include <linux/cache.h>
265 #include <linux/err.h>
266 #include <linux/crypto.h>
267 #include <linux/time.h>
269 #include <net/icmp.h>
271 #include <net/xfrm.h>
273 #include <net/netdma.h>
274 #include <net/sock.h>
276 #include <asm/uaccess.h>
277 #include <asm/ioctls.h>
279 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281 struct percpu_counter tcp_orphan_count;
282 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284 int sysctl_tcp_mem[3] __read_mostly;
285 int sysctl_tcp_wmem[3] __read_mostly;
286 int sysctl_tcp_rmem[3] __read_mostly;
288 EXPORT_SYMBOL(sysctl_tcp_mem);
289 EXPORT_SYMBOL(sysctl_tcp_rmem);
290 EXPORT_SYMBOL(sysctl_tcp_wmem);
292 atomic_t tcp_memory_allocated; /* Current allocated memory. */
293 EXPORT_SYMBOL(tcp_memory_allocated);
296 * Current number of TCP sockets.
298 struct percpu_counter tcp_sockets_allocated;
299 EXPORT_SYMBOL(tcp_sockets_allocated);
304 struct tcp_splice_state {
305 struct pipe_inode_info *pipe;
311 * Pressure flag: try to collapse.
312 * Technical note: it is used by multiple contexts non atomically.
313 * All the __sk_mem_schedule() is of this nature: accounting
314 * is strict, actions are advisory and have some latency.
316 int tcp_memory_pressure __read_mostly;
318 EXPORT_SYMBOL(tcp_memory_pressure);
320 void tcp_enter_memory_pressure(struct sock *sk)
322 if (!tcp_memory_pressure) {
323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324 tcp_memory_pressure = 1;
328 EXPORT_SYMBOL(tcp_enter_memory_pressure);
330 /* Convert seconds to retransmits based on initial and max timeout */
331 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
336 int period = timeout;
339 while (seconds > period && res < 255) {
342 if (timeout > rto_max)
350 /* Convert retransmits to seconds based on initial and max timeout */
351 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
359 if (timeout > rto_max)
368 * Wait for a TCP event.
370 * Note that we don't need to lock the socket, as the upper poll layers
371 * take care of normal races (between the test and the event) and we don't
372 * go look at any of the socket buffers directly.
374 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
377 struct sock *sk = sock->sk;
378 struct tcp_sock *tp = tcp_sk(sk);
380 sock_poll_wait(file, sk->sk_sleep, wait);
381 if (sk->sk_state == TCP_LISTEN)
382 return inet_csk_listen_poll(sk);
384 /* Socket is not locked. We are protected from async events
385 * by poll logic and correct handling of state changes
386 * made by other threads is impossible in any case.
394 * POLLHUP is certainly not done right. But poll() doesn't
395 * have a notion of HUP in just one direction, and for a
396 * socket the read side is more interesting.
398 * Some poll() documentation says that POLLHUP is incompatible
399 * with the POLLOUT/POLLWR flags, so somebody should check this
400 * all. But careful, it tends to be safer to return too many
401 * bits than too few, and you can easily break real applications
402 * if you don't tell them that something has hung up!
406 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
407 * our fs/select.c). It means that after we received EOF,
408 * poll always returns immediately, making impossible poll() on write()
409 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
410 * if and only if shutdown has been made in both directions.
411 * Actually, it is interesting to look how Solaris and DUX
412 * solve this dilemma. I would prefer, if POLLHUP were maskable,
413 * then we could set it on SND_SHUTDOWN. BTW examples given
414 * in Stevens' books assume exactly this behaviour, it explains
415 * why POLLHUP is incompatible with POLLOUT. --ANK
417 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
418 * blocking on fresh not-connected or disconnected socket. --ANK
420 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
422 if (sk->sk_shutdown & RCV_SHUTDOWN)
423 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
426 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
427 int target = sock_rcvlowat(sk, 0, INT_MAX);
429 if (tp->urg_seq == tp->copied_seq &&
430 !sock_flag(sk, SOCK_URGINLINE) &&
434 /* Potential race condition. If read of tp below will
435 * escape above sk->sk_state, we can be illegally awaken
436 * in SYN_* states. */
437 if (tp->rcv_nxt - tp->copied_seq >= target)
438 mask |= POLLIN | POLLRDNORM;
440 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
441 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
442 mask |= POLLOUT | POLLWRNORM;
443 } else { /* send SIGIO later */
444 set_bit(SOCK_ASYNC_NOSPACE,
445 &sk->sk_socket->flags);
446 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
448 /* Race breaker. If space is freed after
449 * wspace test but before the flags are set,
450 * IO signal will be lost.
452 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
453 mask |= POLLOUT | POLLWRNORM;
457 if (tp->urg_data & TCP_URG_VALID)
463 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
465 struct tcp_sock *tp = tcp_sk(sk);
470 if (sk->sk_state == TCP_LISTEN)
474 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
476 else if (sock_flag(sk, SOCK_URGINLINE) ||
478 before(tp->urg_seq, tp->copied_seq) ||
479 !before(tp->urg_seq, tp->rcv_nxt)) {
482 answ = tp->rcv_nxt - tp->copied_seq;
484 /* Subtract 1, if FIN is in queue. */
485 skb = skb_peek_tail(&sk->sk_receive_queue);
487 answ -= tcp_hdr(skb)->fin;
489 answ = tp->urg_seq - tp->copied_seq;
493 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
496 if (sk->sk_state == TCP_LISTEN)
499 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
502 answ = tp->write_seq - tp->snd_una;
508 return put_user(answ, (int __user *)arg);
511 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
513 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
514 tp->pushed_seq = tp->write_seq;
517 static inline int forced_push(struct tcp_sock *tp)
519 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
522 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
524 struct tcp_sock *tp = tcp_sk(sk);
525 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
528 tcb->seq = tcb->end_seq = tp->write_seq;
529 tcb->flags = TCPCB_FLAG_ACK;
531 skb_header_release(skb);
532 tcp_add_write_queue_tail(sk, skb);
533 sk->sk_wmem_queued += skb->truesize;
534 sk_mem_charge(sk, skb->truesize);
535 if (tp->nonagle & TCP_NAGLE_PUSH)
536 tp->nonagle &= ~TCP_NAGLE_PUSH;
539 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
542 tp->snd_up = tp->write_seq;
545 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
548 if (tcp_send_head(sk)) {
549 struct tcp_sock *tp = tcp_sk(sk);
551 if (!(flags & MSG_MORE) || forced_push(tp))
552 tcp_mark_push(tp, tcp_write_queue_tail(sk));
554 tcp_mark_urg(tp, flags);
555 __tcp_push_pending_frames(sk, mss_now,
556 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
560 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
561 unsigned int offset, size_t len)
563 struct tcp_splice_state *tss = rd_desc->arg.data;
566 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
569 rd_desc->count -= ret;
573 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
575 /* Store TCP splice context information in read_descriptor_t. */
576 read_descriptor_t rd_desc = {
581 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
585 * tcp_splice_read - splice data from TCP socket to a pipe
586 * @sock: socket to splice from
587 * @ppos: position (not valid)
588 * @pipe: pipe to splice to
589 * @len: number of bytes to splice
590 * @flags: splice modifier flags
593 * Will read pages from given socket and fill them into a pipe.
596 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
597 struct pipe_inode_info *pipe, size_t len,
600 struct sock *sk = sock->sk;
601 struct tcp_splice_state tss = {
611 * We can't seek on a socket input
620 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
622 ret = __tcp_splice_read(sk, &tss);
628 if (sock_flag(sk, SOCK_DONE))
631 ret = sock_error(sk);
634 if (sk->sk_shutdown & RCV_SHUTDOWN)
636 if (sk->sk_state == TCP_CLOSE) {
638 * This occurs when user tries to read
639 * from never connected socket.
641 if (!sock_flag(sk, SOCK_DONE))
649 sk_wait_data(sk, &timeo);
650 if (signal_pending(current)) {
651 ret = sock_intr_errno(timeo);
664 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
665 (sk->sk_shutdown & RCV_SHUTDOWN) ||
666 signal_pending(current))
678 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
682 /* The TCP header must be at least 32-bit aligned. */
683 size = ALIGN(size, 4);
685 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
687 if (sk_wmem_schedule(sk, skb->truesize)) {
689 * Make sure that we have exactly size bytes
690 * available to the caller, no more, no less.
692 skb_reserve(skb, skb_tailroom(skb) - size);
697 sk->sk_prot->enter_memory_pressure(sk);
698 sk_stream_moderate_sndbuf(sk);
703 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
706 struct tcp_sock *tp = tcp_sk(sk);
707 u32 xmit_size_goal, old_size_goal;
709 xmit_size_goal = mss_now;
711 if (large_allowed && sk_can_gso(sk)) {
712 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
713 inet_csk(sk)->icsk_af_ops->net_header_len -
714 inet_csk(sk)->icsk_ext_hdr_len -
717 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
719 /* We try hard to avoid divides here */
720 old_size_goal = tp->xmit_size_goal_segs * mss_now;
722 if (likely(old_size_goal <= xmit_size_goal &&
723 old_size_goal + mss_now > xmit_size_goal)) {
724 xmit_size_goal = old_size_goal;
726 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
727 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
731 return max(xmit_size_goal, mss_now);
734 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
738 mss_now = tcp_current_mss(sk);
739 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
744 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
745 size_t psize, int flags)
747 struct tcp_sock *tp = tcp_sk(sk);
748 int mss_now, size_goal;
751 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
753 /* Wait for a connection to finish. */
754 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
755 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
758 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
760 mss_now = tcp_send_mss(sk, &size_goal, flags);
764 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
768 struct sk_buff *skb = tcp_write_queue_tail(sk);
769 struct page *page = pages[poffset / PAGE_SIZE];
770 int copy, i, can_coalesce;
771 int offset = poffset % PAGE_SIZE;
772 int size = min_t(size_t, psize, PAGE_SIZE - offset);
774 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
776 if (!sk_stream_memory_free(sk))
777 goto wait_for_sndbuf;
779 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
781 goto wait_for_memory;
790 i = skb_shinfo(skb)->nr_frags;
791 can_coalesce = skb_can_coalesce(skb, i, page, offset);
792 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
793 tcp_mark_push(tp, skb);
796 if (!sk_wmem_schedule(sk, copy))
797 goto wait_for_memory;
800 skb_shinfo(skb)->frags[i - 1].size += copy;
803 skb_fill_page_desc(skb, i, page, offset, copy);
807 skb->data_len += copy;
808 skb->truesize += copy;
809 sk->sk_wmem_queued += copy;
810 sk_mem_charge(sk, copy);
811 skb->ip_summed = CHECKSUM_PARTIAL;
812 tp->write_seq += copy;
813 TCP_SKB_CB(skb)->end_seq += copy;
814 skb_shinfo(skb)->gso_segs = 0;
817 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
821 if (!(psize -= copy))
824 if (skb->len < size_goal || (flags & MSG_OOB))
827 if (forced_push(tp)) {
828 tcp_mark_push(tp, skb);
829 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
830 } else if (skb == tcp_send_head(sk))
831 tcp_push_one(sk, mss_now);
835 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
838 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
840 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
843 mss_now = tcp_send_mss(sk, &size_goal, flags);
848 tcp_push(sk, flags, mss_now, tp->nonagle);
855 return sk_stream_error(sk, flags, err);
858 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
859 size_t size, int flags)
862 struct sock *sk = sock->sk;
864 if (!(sk->sk_route_caps & NETIF_F_SG) ||
865 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
866 return sock_no_sendpage(sock, page, offset, size, flags);
870 res = do_tcp_sendpages(sk, &page, offset, size, flags);
876 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
877 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
879 static inline int select_size(struct sock *sk, int sg)
881 struct tcp_sock *tp = tcp_sk(sk);
882 int tmp = tp->mss_cache;
888 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
890 if (tmp >= pgbreak &&
891 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
899 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
902 struct sock *sk = sock->sk;
904 struct tcp_sock *tp = tcp_sk(sk);
907 int mss_now, size_goal;
914 flags = msg->msg_flags;
915 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
917 /* Wait for a connection to finish. */
918 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
919 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
922 /* This should be in poll */
923 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
925 mss_now = tcp_send_mss(sk, &size_goal, flags);
927 /* Ok commence sending. */
928 iovlen = msg->msg_iovlen;
933 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
936 sg = sk->sk_route_caps & NETIF_F_SG;
938 while (--iovlen >= 0) {
939 int seglen = iov->iov_len;
940 unsigned char __user *from = iov->iov_base;
948 skb = tcp_write_queue_tail(sk);
949 if (tcp_send_head(sk)) {
950 if (skb->ip_summed == CHECKSUM_NONE)
952 copy = max - skb->len;
957 /* Allocate new segment. If the interface is SG,
958 * allocate skb fitting to single page.
960 if (!sk_stream_memory_free(sk))
961 goto wait_for_sndbuf;
963 skb = sk_stream_alloc_skb(sk,
967 goto wait_for_memory;
970 * Check whether we can use HW checksum.
972 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
973 skb->ip_summed = CHECKSUM_PARTIAL;
980 /* Try to append data to the end of skb. */
984 /* Where to copy to? */
985 if (skb_tailroom(skb) > 0) {
986 /* We have some space in skb head. Superb! */
987 if (copy > skb_tailroom(skb))
988 copy = skb_tailroom(skb);
989 if ((err = skb_add_data(skb, from, copy)) != 0)
993 int i = skb_shinfo(skb)->nr_frags;
994 struct page *page = TCP_PAGE(sk);
995 int off = TCP_OFF(sk);
997 if (skb_can_coalesce(skb, i, page, off) &&
999 /* We can extend the last page
1002 } else if (i == MAX_SKB_FRAGS || !sg) {
1003 /* Need to add new fragment and cannot
1004 * do this because interface is non-SG,
1005 * or because all the page slots are
1007 tcp_mark_push(tp, skb);
1010 if (off == PAGE_SIZE) {
1012 TCP_PAGE(sk) = page = NULL;
1018 if (copy > PAGE_SIZE - off)
1019 copy = PAGE_SIZE - off;
1021 if (!sk_wmem_schedule(sk, copy))
1022 goto wait_for_memory;
1025 /* Allocate new cache page. */
1026 if (!(page = sk_stream_alloc_page(sk)))
1027 goto wait_for_memory;
1030 /* Time to copy data. We are close to
1032 err = skb_copy_to_page(sk, from, skb, page,
1035 /* If this page was new, give it to the
1036 * socket so it does not get leaked.
1038 if (!TCP_PAGE(sk)) {
1039 TCP_PAGE(sk) = page;
1045 /* Update the skb. */
1047 skb_shinfo(skb)->frags[i - 1].size +=
1050 skb_fill_page_desc(skb, i, page, off, copy);
1053 } else if (off + copy < PAGE_SIZE) {
1055 TCP_PAGE(sk) = page;
1059 TCP_OFF(sk) = off + copy;
1063 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1065 tp->write_seq += copy;
1066 TCP_SKB_CB(skb)->end_seq += copy;
1067 skb_shinfo(skb)->gso_segs = 0;
1071 if ((seglen -= copy) == 0 && iovlen == 0)
1074 if (skb->len < max || (flags & MSG_OOB))
1077 if (forced_push(tp)) {
1078 tcp_mark_push(tp, skb);
1079 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1080 } else if (skb == tcp_send_head(sk))
1081 tcp_push_one(sk, mss_now);
1085 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1088 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1090 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1093 mss_now = tcp_send_mss(sk, &size_goal, flags);
1099 tcp_push(sk, flags, mss_now, tp->nonagle);
1100 TCP_CHECK_TIMER(sk);
1106 tcp_unlink_write_queue(skb, sk);
1107 /* It is the one place in all of TCP, except connection
1108 * reset, where we can be unlinking the send_head.
1110 tcp_check_send_head(sk, skb);
1111 sk_wmem_free_skb(sk, skb);
1118 err = sk_stream_error(sk, flags, err);
1119 TCP_CHECK_TIMER(sk);
1125 * Handle reading urgent data. BSD has very simple semantics for
1126 * this, no blocking and very strange errors 8)
1129 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1131 struct tcp_sock *tp = tcp_sk(sk);
1133 /* No URG data to read. */
1134 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1135 tp->urg_data == TCP_URG_READ)
1136 return -EINVAL; /* Yes this is right ! */
1138 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1141 if (tp->urg_data & TCP_URG_VALID) {
1143 char c = tp->urg_data;
1145 if (!(flags & MSG_PEEK))
1146 tp->urg_data = TCP_URG_READ;
1148 /* Read urgent data. */
1149 msg->msg_flags |= MSG_OOB;
1152 if (!(flags & MSG_TRUNC))
1153 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1156 msg->msg_flags |= MSG_TRUNC;
1158 return err ? -EFAULT : len;
1161 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1164 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1165 * the available implementations agree in this case:
1166 * this call should never block, independent of the
1167 * blocking state of the socket.
1168 * Mike <pall@rz.uni-karlsruhe.de>
1173 /* Clean up the receive buffer for full frames taken by the user,
1174 * then send an ACK if necessary. COPIED is the number of bytes
1175 * tcp_recvmsg has given to the user so far, it speeds up the
1176 * calculation of whether or not we must ACK for the sake of
1179 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1181 struct tcp_sock *tp = tcp_sk(sk);
1182 int time_to_ack = 0;
1185 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1187 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1188 KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1189 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1192 if (inet_csk_ack_scheduled(sk)) {
1193 const struct inet_connection_sock *icsk = inet_csk(sk);
1194 /* Delayed ACKs frequently hit locked sockets during bulk
1196 if (icsk->icsk_ack.blocked ||
1197 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1198 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1200 * If this read emptied read buffer, we send ACK, if
1201 * connection is not bidirectional, user drained
1202 * receive buffer and there was a small segment
1206 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1207 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1208 !icsk->icsk_ack.pingpong)) &&
1209 !atomic_read(&sk->sk_rmem_alloc)))
1213 /* We send an ACK if we can now advertise a non-zero window
1214 * which has been raised "significantly".
1216 * Even if window raised up to infinity, do not send window open ACK
1217 * in states, where we will not receive more. It is useless.
1219 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1220 __u32 rcv_window_now = tcp_receive_window(tp);
1222 /* Optimize, __tcp_select_window() is not cheap. */
1223 if (2*rcv_window_now <= tp->window_clamp) {
1224 __u32 new_window = __tcp_select_window(sk);
1226 /* Send ACK now, if this read freed lots of space
1227 * in our buffer. Certainly, new_window is new window.
1228 * We can advertise it now, if it is not less than current one.
1229 * "Lots" means "at least twice" here.
1231 if (new_window && new_window >= 2 * rcv_window_now)
1239 static void tcp_prequeue_process(struct sock *sk)
1241 struct sk_buff *skb;
1242 struct tcp_sock *tp = tcp_sk(sk);
1244 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1246 /* RX process wants to run with disabled BHs, though it is not
1249 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1250 sk_backlog_rcv(sk, skb);
1253 /* Clear memory counter. */
1254 tp->ucopy.memory = 0;
1257 #ifdef CONFIG_NET_DMA
1258 static void tcp_service_net_dma(struct sock *sk, bool wait)
1260 dma_cookie_t done, used;
1261 dma_cookie_t last_issued;
1262 struct tcp_sock *tp = tcp_sk(sk);
1264 if (!tp->ucopy.dma_chan)
1267 last_issued = tp->ucopy.dma_cookie;
1268 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1271 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1273 &used) == DMA_SUCCESS) {
1274 /* Safe to free early-copied skbs now */
1275 __skb_queue_purge(&sk->sk_async_wait_queue);
1278 struct sk_buff *skb;
1279 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1280 (dma_async_is_complete(skb->dma_cookie, done,
1281 used) == DMA_SUCCESS)) {
1282 __skb_dequeue(&sk->sk_async_wait_queue);
1290 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1292 struct sk_buff *skb;
1295 skb_queue_walk(&sk->sk_receive_queue, skb) {
1296 offset = seq - TCP_SKB_CB(skb)->seq;
1297 if (tcp_hdr(skb)->syn)
1299 if (offset < skb->len || tcp_hdr(skb)->fin) {
1308 * This routine provides an alternative to tcp_recvmsg() for routines
1309 * that would like to handle copying from skbuffs directly in 'sendfile'
1312 * - It is assumed that the socket was locked by the caller.
1313 * - The routine does not block.
1314 * - At present, there is no support for reading OOB data
1315 * or for 'peeking' the socket using this routine
1316 * (although both would be easy to implement).
1318 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1319 sk_read_actor_t recv_actor)
1321 struct sk_buff *skb;
1322 struct tcp_sock *tp = tcp_sk(sk);
1323 u32 seq = tp->copied_seq;
1327 if (sk->sk_state == TCP_LISTEN)
1329 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1330 if (offset < skb->len) {
1334 len = skb->len - offset;
1335 /* Stop reading if we hit a patch of urgent data */
1337 u32 urg_offset = tp->urg_seq - seq;
1338 if (urg_offset < len)
1343 used = recv_actor(desc, skb, offset, len);
1348 } else if (used <= len) {
1354 * If recv_actor drops the lock (e.g. TCP splice
1355 * receive) the skb pointer might be invalid when
1356 * getting here: tcp_collapse might have deleted it
1357 * while aggregating skbs from the socket queue.
1359 skb = tcp_recv_skb(sk, seq-1, &offset);
1360 if (!skb || (offset+1 != skb->len))
1363 if (tcp_hdr(skb)->fin) {
1364 sk_eat_skb(sk, skb, 0);
1368 sk_eat_skb(sk, skb, 0);
1372 tp->copied_seq = seq;
1374 tcp_rcv_space_adjust(sk);
1376 /* Clean up data we have read: This will do ACK frames. */
1378 tcp_cleanup_rbuf(sk, copied);
1383 * This routine copies from a sock struct into the user buffer.
1385 * Technical note: in 2.3 we work on _locked_ socket, so that
1386 * tricks with *seq access order and skb->users are not required.
1387 * Probably, code can be easily improved even more.
1390 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1391 size_t len, int nonblock, int flags, int *addr_len)
1393 struct tcp_sock *tp = tcp_sk(sk);
1399 int target; /* Read at least this many bytes */
1401 struct task_struct *user_recv = NULL;
1402 int copied_early = 0;
1403 struct sk_buff *skb;
1408 TCP_CHECK_TIMER(sk);
1411 if (sk->sk_state == TCP_LISTEN)
1414 timeo = sock_rcvtimeo(sk, nonblock);
1416 /* Urgent data needs to be handled specially. */
1417 if (flags & MSG_OOB)
1420 seq = &tp->copied_seq;
1421 if (flags & MSG_PEEK) {
1422 peek_seq = tp->copied_seq;
1426 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1428 #ifdef CONFIG_NET_DMA
1429 tp->ucopy.dma_chan = NULL;
1431 skb = skb_peek_tail(&sk->sk_receive_queue);
1436 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1437 if ((available < target) &&
1438 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1439 !sysctl_tcp_low_latency &&
1440 dma_find_channel(DMA_MEMCPY)) {
1441 preempt_enable_no_resched();
1442 tp->ucopy.pinned_list =
1443 dma_pin_iovec_pages(msg->msg_iov, len);
1445 preempt_enable_no_resched();
1453 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1454 if (tp->urg_data && tp->urg_seq == *seq) {
1457 if (signal_pending(current)) {
1458 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1463 /* Next get a buffer. */
1465 skb_queue_walk(&sk->sk_receive_queue, skb) {
1466 /* Now that we have two receive queues this
1469 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1470 KERN_INFO "recvmsg bug: copied %X "
1471 "seq %X rcvnxt %X fl %X\n", *seq,
1472 TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1476 offset = *seq - TCP_SKB_CB(skb)->seq;
1477 if (tcp_hdr(skb)->syn)
1479 if (offset < skb->len)
1481 if (tcp_hdr(skb)->fin)
1483 WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1484 "copied %X seq %X rcvnxt %X fl %X\n",
1485 *seq, TCP_SKB_CB(skb)->seq,
1486 tp->rcv_nxt, flags);
1489 /* Well, if we have backlog, try to process it now yet. */
1491 if (copied >= target && !sk->sk_backlog.tail)
1496 sk->sk_state == TCP_CLOSE ||
1497 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1499 signal_pending(current))
1502 if (sock_flag(sk, SOCK_DONE))
1506 copied = sock_error(sk);
1510 if (sk->sk_shutdown & RCV_SHUTDOWN)
1513 if (sk->sk_state == TCP_CLOSE) {
1514 if (!sock_flag(sk, SOCK_DONE)) {
1515 /* This occurs when user tries to read
1516 * from never connected socket.
1529 if (signal_pending(current)) {
1530 copied = sock_intr_errno(timeo);
1535 tcp_cleanup_rbuf(sk, copied);
1537 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1538 /* Install new reader */
1539 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1540 user_recv = current;
1541 tp->ucopy.task = user_recv;
1542 tp->ucopy.iov = msg->msg_iov;
1545 tp->ucopy.len = len;
1547 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1548 !(flags & (MSG_PEEK | MSG_TRUNC)));
1550 /* Ugly... If prequeue is not empty, we have to
1551 * process it before releasing socket, otherwise
1552 * order will be broken at second iteration.
1553 * More elegant solution is required!!!
1555 * Look: we have the following (pseudo)queues:
1557 * 1. packets in flight
1562 * Each queue can be processed only if the next ones
1563 * are empty. At this point we have empty receive_queue.
1564 * But prequeue _can_ be not empty after 2nd iteration,
1565 * when we jumped to start of loop because backlog
1566 * processing added something to receive_queue.
1567 * We cannot release_sock(), because backlog contains
1568 * packets arrived _after_ prequeued ones.
1570 * Shortly, algorithm is clear --- to process all
1571 * the queues in order. We could make it more directly,
1572 * requeueing packets from backlog to prequeue, if
1573 * is not empty. It is more elegant, but eats cycles,
1576 if (!skb_queue_empty(&tp->ucopy.prequeue))
1579 /* __ Set realtime policy in scheduler __ */
1582 #ifdef CONFIG_NET_DMA
1583 if (tp->ucopy.dma_chan)
1584 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1586 if (copied >= target) {
1587 /* Do not sleep, just process backlog. */
1591 sk_wait_data(sk, &timeo);
1593 #ifdef CONFIG_NET_DMA
1594 tcp_service_net_dma(sk, false); /* Don't block */
1595 tp->ucopy.wakeup = 0;
1601 /* __ Restore normal policy in scheduler __ */
1603 if ((chunk = len - tp->ucopy.len) != 0) {
1604 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1609 if (tp->rcv_nxt == tp->copied_seq &&
1610 !skb_queue_empty(&tp->ucopy.prequeue)) {
1612 tcp_prequeue_process(sk);
1614 if ((chunk = len - tp->ucopy.len) != 0) {
1615 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1621 if ((flags & MSG_PEEK) &&
1622 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1623 if (net_ratelimit())
1624 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1625 current->comm, task_pid_nr(current));
1626 peek_seq = tp->copied_seq;
1631 /* Ok so how much can we use? */
1632 used = skb->len - offset;
1636 /* Do we have urgent data here? */
1638 u32 urg_offset = tp->urg_seq - *seq;
1639 if (urg_offset < used) {
1641 if (!sock_flag(sk, SOCK_URGINLINE)) {
1654 if (!(flags & MSG_TRUNC)) {
1655 #ifdef CONFIG_NET_DMA
1656 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1657 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1659 if (tp->ucopy.dma_chan) {
1660 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1661 tp->ucopy.dma_chan, skb, offset,
1663 tp->ucopy.pinned_list);
1665 if (tp->ucopy.dma_cookie < 0) {
1667 printk(KERN_ALERT "dma_cookie < 0\n");
1669 /* Exception. Bailout! */
1675 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1677 if ((offset + used) == skb->len)
1683 err = skb_copy_datagram_iovec(skb, offset,
1684 msg->msg_iov, used);
1686 /* Exception. Bailout! */
1698 tcp_rcv_space_adjust(sk);
1701 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1703 tcp_fast_path_check(sk);
1705 if (used + offset < skb->len)
1708 if (tcp_hdr(skb)->fin)
1710 if (!(flags & MSG_PEEK)) {
1711 sk_eat_skb(sk, skb, copied_early);
1717 /* Process the FIN. */
1719 if (!(flags & MSG_PEEK)) {
1720 sk_eat_skb(sk, skb, copied_early);
1727 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1730 tp->ucopy.len = copied > 0 ? len : 0;
1732 tcp_prequeue_process(sk);
1734 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1735 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1741 tp->ucopy.task = NULL;
1745 #ifdef CONFIG_NET_DMA
1746 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1747 tp->ucopy.dma_chan = NULL;
1749 if (tp->ucopy.pinned_list) {
1750 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1751 tp->ucopy.pinned_list = NULL;
1755 /* According to UNIX98, msg_name/msg_namelen are ignored
1756 * on connected socket. I was just happy when found this 8) --ANK
1759 /* Clean up data we have read: This will do ACK frames. */
1760 tcp_cleanup_rbuf(sk, copied);
1762 TCP_CHECK_TIMER(sk);
1767 TCP_CHECK_TIMER(sk);
1772 err = tcp_recv_urg(sk, msg, len, flags);
1776 void tcp_set_state(struct sock *sk, int state)
1778 int oldstate = sk->sk_state;
1781 case TCP_ESTABLISHED:
1782 if (oldstate != TCP_ESTABLISHED)
1783 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1787 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1788 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1790 sk->sk_prot->unhash(sk);
1791 if (inet_csk(sk)->icsk_bind_hash &&
1792 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1796 if (oldstate == TCP_ESTABLISHED)
1797 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1800 /* Change state AFTER socket is unhashed to avoid closed
1801 * socket sitting in hash tables.
1803 sk->sk_state = state;
1806 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1809 EXPORT_SYMBOL_GPL(tcp_set_state);
1812 * State processing on a close. This implements the state shift for
1813 * sending our FIN frame. Note that we only send a FIN for some
1814 * states. A shutdown() may have already sent the FIN, or we may be
1818 static const unsigned char new_state[16] = {
1819 /* current state: new state: action: */
1820 /* (Invalid) */ TCP_CLOSE,
1821 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1822 /* TCP_SYN_SENT */ TCP_CLOSE,
1823 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1824 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1825 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1826 /* TCP_TIME_WAIT */ TCP_CLOSE,
1827 /* TCP_CLOSE */ TCP_CLOSE,
1828 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1829 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1830 /* TCP_LISTEN */ TCP_CLOSE,
1831 /* TCP_CLOSING */ TCP_CLOSING,
1834 static int tcp_close_state(struct sock *sk)
1836 int next = (int)new_state[sk->sk_state];
1837 int ns = next & TCP_STATE_MASK;
1839 tcp_set_state(sk, ns);
1841 return next & TCP_ACTION_FIN;
1845 * Shutdown the sending side of a connection. Much like close except
1846 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1849 void tcp_shutdown(struct sock *sk, int how)
1851 /* We need to grab some memory, and put together a FIN,
1852 * and then put it into the queue to be sent.
1853 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1855 if (!(how & SEND_SHUTDOWN))
1858 /* If we've already sent a FIN, or it's a closed state, skip this. */
1859 if ((1 << sk->sk_state) &
1860 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1861 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1862 /* Clear out any half completed packets. FIN if needed. */
1863 if (tcp_close_state(sk))
1868 void tcp_close(struct sock *sk, long timeout)
1870 struct sk_buff *skb;
1871 int data_was_unread = 0;
1875 sk->sk_shutdown = SHUTDOWN_MASK;
1877 if (sk->sk_state == TCP_LISTEN) {
1878 tcp_set_state(sk, TCP_CLOSE);
1881 inet_csk_listen_stop(sk);
1883 goto adjudge_to_death;
1886 /* We need to flush the recv. buffs. We do this only on the
1887 * descriptor close, not protocol-sourced closes, because the
1888 * reader process may not have drained the data yet!
1890 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1891 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1893 data_was_unread += len;
1899 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1900 * data was lost. To witness the awful effects of the old behavior of
1901 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1902 * GET in an FTP client, suspend the process, wait for the client to
1903 * advertise a zero window, then kill -9 the FTP client, wheee...
1904 * Note: timeout is always zero in such a case.
1906 if (data_was_unread) {
1907 /* Unread data was tossed, zap the connection. */
1908 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1909 tcp_set_state(sk, TCP_CLOSE);
1910 tcp_send_active_reset(sk, sk->sk_allocation);
1911 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1912 /* Check zero linger _after_ checking for unread data. */
1913 sk->sk_prot->disconnect(sk, 0);
1914 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1915 } else if (tcp_close_state(sk)) {
1916 /* We FIN if the application ate all the data before
1917 * zapping the connection.
1920 /* RED-PEN. Formally speaking, we have broken TCP state
1921 * machine. State transitions:
1923 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1924 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1925 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1927 * are legal only when FIN has been sent (i.e. in window),
1928 * rather than queued out of window. Purists blame.
1930 * F.e. "RFC state" is ESTABLISHED,
1931 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1933 * The visible declinations are that sometimes
1934 * we enter time-wait state, when it is not required really
1935 * (harmless), do not send active resets, when they are
1936 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1937 * they look as CLOSING or LAST_ACK for Linux)
1938 * Probably, I missed some more holelets.
1944 sk_stream_wait_close(sk, timeout);
1947 state = sk->sk_state;
1951 /* It is the last release_sock in its life. It will remove backlog. */
1955 /* Now socket is owned by kernel and we acquire BH lock
1956 to finish close. No need to check for user refs.
1960 WARN_ON(sock_owned_by_user(sk));
1962 percpu_counter_inc(sk->sk_prot->orphan_count);
1964 /* Have we already been destroyed by a softirq or backlog? */
1965 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1968 /* This is a (useful) BSD violating of the RFC. There is a
1969 * problem with TCP as specified in that the other end could
1970 * keep a socket open forever with no application left this end.
1971 * We use a 3 minute timeout (about the same as BSD) then kill
1972 * our end. If they send after that then tough - BUT: long enough
1973 * that we won't make the old 4*rto = almost no time - whoops
1976 * Nope, it was not mistake. It is really desired behaviour
1977 * f.e. on http servers, when such sockets are useless, but
1978 * consume significant resources. Let's do it with special
1979 * linger2 option. --ANK
1982 if (sk->sk_state == TCP_FIN_WAIT2) {
1983 struct tcp_sock *tp = tcp_sk(sk);
1984 if (tp->linger2 < 0) {
1985 tcp_set_state(sk, TCP_CLOSE);
1986 tcp_send_active_reset(sk, GFP_ATOMIC);
1987 NET_INC_STATS_BH(sock_net(sk),
1988 LINUX_MIB_TCPABORTONLINGER);
1990 const int tmo = tcp_fin_time(sk);
1992 if (tmo > TCP_TIMEWAIT_LEN) {
1993 inet_csk_reset_keepalive_timer(sk,
1994 tmo - TCP_TIMEWAIT_LEN);
1996 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2001 if (sk->sk_state != TCP_CLOSE) {
2002 int orphan_count = percpu_counter_read_positive(
2003 sk->sk_prot->orphan_count);
2006 if (tcp_too_many_orphans(sk, orphan_count)) {
2007 if (net_ratelimit())
2008 printk(KERN_INFO "TCP: too many of orphaned "
2010 tcp_set_state(sk, TCP_CLOSE);
2011 tcp_send_active_reset(sk, GFP_ATOMIC);
2012 NET_INC_STATS_BH(sock_net(sk),
2013 LINUX_MIB_TCPABORTONMEMORY);
2017 if (sk->sk_state == TCP_CLOSE)
2018 inet_csk_destroy_sock(sk);
2019 /* Otherwise, socket is reprieved until protocol close. */
2027 /* These states need RST on ABORT according to RFC793 */
2029 static inline int tcp_need_reset(int state)
2031 return (1 << state) &
2032 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2033 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2036 int tcp_disconnect(struct sock *sk, int flags)
2038 struct inet_sock *inet = inet_sk(sk);
2039 struct inet_connection_sock *icsk = inet_csk(sk);
2040 struct tcp_sock *tp = tcp_sk(sk);
2042 int old_state = sk->sk_state;
2044 if (old_state != TCP_CLOSE)
2045 tcp_set_state(sk, TCP_CLOSE);
2047 /* ABORT function of RFC793 */
2048 if (old_state == TCP_LISTEN) {
2049 inet_csk_listen_stop(sk);
2050 } else if (tcp_need_reset(old_state) ||
2051 (tp->snd_nxt != tp->write_seq &&
2052 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2053 /* The last check adjusts for discrepancy of Linux wrt. RFC
2056 tcp_send_active_reset(sk, gfp_any());
2057 sk->sk_err = ECONNRESET;
2058 } else if (old_state == TCP_SYN_SENT)
2059 sk->sk_err = ECONNRESET;
2061 tcp_clear_xmit_timers(sk);
2062 __skb_queue_purge(&sk->sk_receive_queue);
2063 tcp_write_queue_purge(sk);
2064 __skb_queue_purge(&tp->out_of_order_queue);
2065 #ifdef CONFIG_NET_DMA
2066 __skb_queue_purge(&sk->sk_async_wait_queue);
2069 inet->inet_dport = 0;
2071 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2072 inet_reset_saddr(sk);
2074 sk->sk_shutdown = 0;
2075 sock_reset_flag(sk, SOCK_DONE);
2077 if ((tp->write_seq += tp->max_window + 2) == 0)
2079 icsk->icsk_backoff = 0;
2081 icsk->icsk_probes_out = 0;
2082 tp->packets_out = 0;
2083 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2084 tp->snd_cwnd_cnt = 0;
2085 tp->bytes_acked = 0;
2086 tp->window_clamp = 0;
2087 tcp_set_ca_state(sk, TCP_CA_Open);
2088 tcp_clear_retrans(tp);
2089 inet_csk_delack_init(sk);
2090 tcp_init_send_head(sk);
2091 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2094 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2096 sk->sk_error_report(sk);
2101 * Socket option code for TCP.
2103 static int do_tcp_setsockopt(struct sock *sk, int level,
2104 int optname, char __user *optval, unsigned int optlen)
2106 struct tcp_sock *tp = tcp_sk(sk);
2107 struct inet_connection_sock *icsk = inet_csk(sk);
2111 /* These are data/string values, all the others are ints */
2113 case TCP_CONGESTION: {
2114 char name[TCP_CA_NAME_MAX];
2119 val = strncpy_from_user(name, optval,
2120 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2126 err = tcp_set_congestion_control(sk, name);
2130 case TCP_COOKIE_TRANSACTIONS: {
2131 struct tcp_cookie_transactions ctd;
2132 struct tcp_cookie_values *cvp = NULL;
2134 if (sizeof(ctd) > optlen)
2136 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2139 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2140 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2143 if (ctd.tcpct_cookie_desired == 0) {
2144 /* default to global value */
2145 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2146 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2147 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2151 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2152 /* Supercedes all other values */
2154 if (tp->cookie_values != NULL) {
2155 kref_put(&tp->cookie_values->kref,
2156 tcp_cookie_values_release);
2157 tp->cookie_values = NULL;
2159 tp->rx_opt.cookie_in_always = 0; /* false */
2160 tp->rx_opt.cookie_out_never = 1; /* true */
2165 /* Allocate ancillary memory before locking.
2167 if (ctd.tcpct_used > 0 ||
2168 (tp->cookie_values == NULL &&
2169 (sysctl_tcp_cookie_size > 0 ||
2170 ctd.tcpct_cookie_desired > 0 ||
2171 ctd.tcpct_s_data_desired > 0))) {
2172 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2178 tp->rx_opt.cookie_in_always =
2179 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2180 tp->rx_opt.cookie_out_never = 0; /* false */
2182 if (tp->cookie_values != NULL) {
2184 /* Changed values are recorded by a changed
2185 * pointer, ensuring the cookie will differ,
2186 * without separately hashing each value later.
2188 kref_put(&tp->cookie_values->kref,
2189 tcp_cookie_values_release);
2190 kref_init(&cvp->kref);
2191 tp->cookie_values = cvp;
2193 cvp = tp->cookie_values;
2197 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2199 if (ctd.tcpct_used > 0) {
2200 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2202 cvp->s_data_desired = ctd.tcpct_used;
2203 cvp->s_data_constant = 1; /* true */
2205 /* No constant payload data. */
2206 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2207 cvp->s_data_constant = 0; /* false */
2218 if (optlen < sizeof(int))
2221 if (get_user(val, (int __user *)optval))
2228 /* Values greater than interface MTU won't take effect. However
2229 * at the point when this call is done we typically don't yet
2230 * know which interface is going to be used */
2231 if (val < 8 || val > MAX_TCP_WINDOW) {
2235 tp->rx_opt.user_mss = val;
2240 /* TCP_NODELAY is weaker than TCP_CORK, so that
2241 * this option on corked socket is remembered, but
2242 * it is not activated until cork is cleared.
2244 * However, when TCP_NODELAY is set we make
2245 * an explicit push, which overrides even TCP_CORK
2246 * for currently queued segments.
2248 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2249 tcp_push_pending_frames(sk);
2251 tp->nonagle &= ~TCP_NAGLE_OFF;
2255 case TCP_THIN_LINEAR_TIMEOUTS:
2256 if (val < 0 || val > 1)
2262 case TCP_THIN_DUPACK:
2263 if (val < 0 || val > 1)
2266 tp->thin_dupack = val;
2270 /* When set indicates to always queue non-full frames.
2271 * Later the user clears this option and we transmit
2272 * any pending partial frames in the queue. This is
2273 * meant to be used alongside sendfile() to get properly
2274 * filled frames when the user (for example) must write
2275 * out headers with a write() call first and then use
2276 * sendfile to send out the data parts.
2278 * TCP_CORK can be set together with TCP_NODELAY and it is
2279 * stronger than TCP_NODELAY.
2282 tp->nonagle |= TCP_NAGLE_CORK;
2284 tp->nonagle &= ~TCP_NAGLE_CORK;
2285 if (tp->nonagle&TCP_NAGLE_OFF)
2286 tp->nonagle |= TCP_NAGLE_PUSH;
2287 tcp_push_pending_frames(sk);
2292 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2295 tp->keepalive_time = val * HZ;
2296 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2297 !((1 << sk->sk_state) &
2298 (TCPF_CLOSE | TCPF_LISTEN))) {
2299 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2300 if (tp->keepalive_time > elapsed)
2301 elapsed = tp->keepalive_time - elapsed;
2304 inet_csk_reset_keepalive_timer(sk, elapsed);
2309 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2312 tp->keepalive_intvl = val * HZ;
2315 if (val < 1 || val > MAX_TCP_KEEPCNT)
2318 tp->keepalive_probes = val;
2321 if (val < 1 || val > MAX_TCP_SYNCNT)
2324 icsk->icsk_syn_retries = val;
2330 else if (val > sysctl_tcp_fin_timeout / HZ)
2333 tp->linger2 = val * HZ;
2336 case TCP_DEFER_ACCEPT:
2337 /* Translate value in seconds to number of retransmits */
2338 icsk->icsk_accept_queue.rskq_defer_accept =
2339 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2343 case TCP_WINDOW_CLAMP:
2345 if (sk->sk_state != TCP_CLOSE) {
2349 tp->window_clamp = 0;
2351 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2352 SOCK_MIN_RCVBUF / 2 : val;
2357 icsk->icsk_ack.pingpong = 1;
2359 icsk->icsk_ack.pingpong = 0;
2360 if ((1 << sk->sk_state) &
2361 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2362 inet_csk_ack_scheduled(sk)) {
2363 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2364 tcp_cleanup_rbuf(sk, 1);
2366 icsk->icsk_ack.pingpong = 1;
2371 #ifdef CONFIG_TCP_MD5SIG
2373 /* Read the IP->Key mappings from userspace */
2374 err = tp->af_specific->md5_parse(sk, optval, optlen);
2387 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2388 unsigned int optlen)
2390 struct inet_connection_sock *icsk = inet_csk(sk);
2392 if (level != SOL_TCP)
2393 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2395 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2398 #ifdef CONFIG_COMPAT
2399 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2400 char __user *optval, unsigned int optlen)
2402 if (level != SOL_TCP)
2403 return inet_csk_compat_setsockopt(sk, level, optname,
2405 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2408 EXPORT_SYMBOL(compat_tcp_setsockopt);
2411 /* Return information about state of tcp endpoint in API format. */
2412 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2414 struct tcp_sock *tp = tcp_sk(sk);
2415 const struct inet_connection_sock *icsk = inet_csk(sk);
2416 u32 now = tcp_time_stamp;
2418 memset(info, 0, sizeof(*info));
2420 info->tcpi_state = sk->sk_state;
2421 info->tcpi_ca_state = icsk->icsk_ca_state;
2422 info->tcpi_retransmits = icsk->icsk_retransmits;
2423 info->tcpi_probes = icsk->icsk_probes_out;
2424 info->tcpi_backoff = icsk->icsk_backoff;
2426 if (tp->rx_opt.tstamp_ok)
2427 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2428 if (tcp_is_sack(tp))
2429 info->tcpi_options |= TCPI_OPT_SACK;
2430 if (tp->rx_opt.wscale_ok) {
2431 info->tcpi_options |= TCPI_OPT_WSCALE;
2432 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2433 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2436 if (tp->ecn_flags&TCP_ECN_OK)
2437 info->tcpi_options |= TCPI_OPT_ECN;
2439 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2440 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2441 info->tcpi_snd_mss = tp->mss_cache;
2442 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2444 if (sk->sk_state == TCP_LISTEN) {
2445 info->tcpi_unacked = sk->sk_ack_backlog;
2446 info->tcpi_sacked = sk->sk_max_ack_backlog;
2448 info->tcpi_unacked = tp->packets_out;
2449 info->tcpi_sacked = tp->sacked_out;
2451 info->tcpi_lost = tp->lost_out;
2452 info->tcpi_retrans = tp->retrans_out;
2453 info->tcpi_fackets = tp->fackets_out;
2455 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2456 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2457 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2459 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2460 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2461 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2462 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2463 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2464 info->tcpi_snd_cwnd = tp->snd_cwnd;
2465 info->tcpi_advmss = tp->advmss;
2466 info->tcpi_reordering = tp->reordering;
2468 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2469 info->tcpi_rcv_space = tp->rcvq_space.space;
2471 info->tcpi_total_retrans = tp->total_retrans;
2474 EXPORT_SYMBOL_GPL(tcp_get_info);
2476 static int do_tcp_getsockopt(struct sock *sk, int level,
2477 int optname, char __user *optval, int __user *optlen)
2479 struct inet_connection_sock *icsk = inet_csk(sk);
2480 struct tcp_sock *tp = tcp_sk(sk);
2483 if (get_user(len, optlen))
2486 len = min_t(unsigned int, len, sizeof(int));
2493 val = tp->mss_cache;
2494 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2495 val = tp->rx_opt.user_mss;
2498 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2501 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2504 val = keepalive_time_when(tp) / HZ;
2507 val = keepalive_intvl_when(tp) / HZ;
2510 val = keepalive_probes(tp);
2513 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2518 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2520 case TCP_DEFER_ACCEPT:
2521 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2522 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2524 case TCP_WINDOW_CLAMP:
2525 val = tp->window_clamp;
2528 struct tcp_info info;
2530 if (get_user(len, optlen))
2533 tcp_get_info(sk, &info);
2535 len = min_t(unsigned int, len, sizeof(info));
2536 if (put_user(len, optlen))
2538 if (copy_to_user(optval, &info, len))
2543 val = !icsk->icsk_ack.pingpong;
2546 case TCP_CONGESTION:
2547 if (get_user(len, optlen))
2549 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2550 if (put_user(len, optlen))
2552 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2556 case TCP_COOKIE_TRANSACTIONS: {
2557 struct tcp_cookie_transactions ctd;
2558 struct tcp_cookie_values *cvp = tp->cookie_values;
2560 if (get_user(len, optlen))
2562 if (len < sizeof(ctd))
2565 memset(&ctd, 0, sizeof(ctd));
2566 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2567 TCP_COOKIE_IN_ALWAYS : 0)
2568 | (tp->rx_opt.cookie_out_never ?
2569 TCP_COOKIE_OUT_NEVER : 0);
2572 ctd.tcpct_flags |= (cvp->s_data_in ?
2574 | (cvp->s_data_out ?
2575 TCP_S_DATA_OUT : 0);
2577 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2578 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2580 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2581 cvp->cookie_pair_size);
2582 ctd.tcpct_used = cvp->cookie_pair_size;
2585 if (put_user(sizeof(ctd), optlen))
2587 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2592 return -ENOPROTOOPT;
2595 if (put_user(len, optlen))
2597 if (copy_to_user(optval, &val, len))
2602 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2605 struct inet_connection_sock *icsk = inet_csk(sk);
2607 if (level != SOL_TCP)
2608 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2610 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2613 #ifdef CONFIG_COMPAT
2614 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2615 char __user *optval, int __user *optlen)
2617 if (level != SOL_TCP)
2618 return inet_csk_compat_getsockopt(sk, level, optname,
2620 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2623 EXPORT_SYMBOL(compat_tcp_getsockopt);
2626 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2628 struct sk_buff *segs = ERR_PTR(-EINVAL);
2633 unsigned int oldlen;
2636 if (!pskb_may_pull(skb, sizeof(*th)))
2640 thlen = th->doff * 4;
2641 if (thlen < sizeof(*th))
2644 if (!pskb_may_pull(skb, thlen))
2647 oldlen = (u16)~skb->len;
2648 __skb_pull(skb, thlen);
2650 mss = skb_shinfo(skb)->gso_size;
2651 if (unlikely(skb->len <= mss))
2654 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2655 /* Packet is from an untrusted source, reset gso_segs. */
2656 int type = skb_shinfo(skb)->gso_type;
2664 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2667 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2673 segs = skb_segment(skb, features);
2677 delta = htonl(oldlen + (thlen + mss));
2681 seq = ntohl(th->seq);
2684 th->fin = th->psh = 0;
2686 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2687 (__force u32)delta));
2688 if (skb->ip_summed != CHECKSUM_PARTIAL)
2690 csum_fold(csum_partial(skb_transport_header(skb),
2697 th->seq = htonl(seq);
2699 } while (skb->next);
2701 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2703 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2704 (__force u32)delta));
2705 if (skb->ip_summed != CHECKSUM_PARTIAL)
2706 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2712 EXPORT_SYMBOL(tcp_tso_segment);
2714 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2716 struct sk_buff **pp = NULL;
2723 unsigned int mss = 1;
2729 off = skb_gro_offset(skb);
2730 hlen = off + sizeof(*th);
2731 th = skb_gro_header_fast(skb, off);
2732 if (skb_gro_header_hard(skb, hlen)) {
2733 th = skb_gro_header_slow(skb, hlen, off);
2738 thlen = th->doff * 4;
2739 if (thlen < sizeof(*th))
2743 if (skb_gro_header_hard(skb, hlen)) {
2744 th = skb_gro_header_slow(skb, hlen, off);
2749 skb_gro_pull(skb, thlen);
2751 len = skb_gro_len(skb);
2752 flags = tcp_flag_word(th);
2754 for (; (p = *head); head = &p->next) {
2755 if (!NAPI_GRO_CB(p)->same_flow)
2760 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2761 NAPI_GRO_CB(p)->same_flow = 0;
2768 goto out_check_final;
2771 flush = NAPI_GRO_CB(p)->flush;
2772 flush |= flags & TCP_FLAG_CWR;
2773 flush |= (flags ^ tcp_flag_word(th2)) &
2774 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2775 flush |= th->ack_seq ^ th2->ack_seq;
2776 for (i = sizeof(*th); i < thlen; i += 4)
2777 flush |= *(u32 *)((u8 *)th + i) ^
2778 *(u32 *)((u8 *)th2 + i);
2780 mss = skb_shinfo(p)->gso_size;
2782 flush |= (len - 1) >= mss;
2783 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2785 if (flush || skb_gro_receive(head, skb)) {
2787 goto out_check_final;
2792 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2796 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2797 TCP_FLAG_SYN | TCP_FLAG_FIN);
2799 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2803 NAPI_GRO_CB(skb)->flush |= flush;
2807 EXPORT_SYMBOL(tcp_gro_receive);
2809 int tcp_gro_complete(struct sk_buff *skb)
2811 struct tcphdr *th = tcp_hdr(skb);
2813 skb->csum_start = skb_transport_header(skb) - skb->head;
2814 skb->csum_offset = offsetof(struct tcphdr, check);
2815 skb->ip_summed = CHECKSUM_PARTIAL;
2817 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2820 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2824 EXPORT_SYMBOL(tcp_gro_complete);
2826 #ifdef CONFIG_TCP_MD5SIG
2827 static unsigned long tcp_md5sig_users;
2828 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2829 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2831 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2834 for_each_possible_cpu(cpu) {
2835 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2837 if (p->md5_desc.tfm)
2838 crypto_free_hash(p->md5_desc.tfm);
2846 void tcp_free_md5sig_pool(void)
2848 struct tcp_md5sig_pool * __percpu *pool = NULL;
2850 spin_lock_bh(&tcp_md5sig_pool_lock);
2851 if (--tcp_md5sig_users == 0) {
2852 pool = tcp_md5sig_pool;
2853 tcp_md5sig_pool = NULL;
2855 spin_unlock_bh(&tcp_md5sig_pool_lock);
2857 __tcp_free_md5sig_pool(pool);
2860 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2862 static struct tcp_md5sig_pool * __percpu *
2863 __tcp_alloc_md5sig_pool(struct sock *sk)
2866 struct tcp_md5sig_pool * __percpu *pool;
2868 pool = alloc_percpu(struct tcp_md5sig_pool *);
2872 for_each_possible_cpu(cpu) {
2873 struct tcp_md5sig_pool *p;
2874 struct crypto_hash *hash;
2876 p = kzalloc(sizeof(*p), sk->sk_allocation);
2879 *per_cpu_ptr(pool, cpu) = p;
2881 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2882 if (!hash || IS_ERR(hash))
2885 p->md5_desc.tfm = hash;
2889 __tcp_free_md5sig_pool(pool);
2893 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2895 struct tcp_md5sig_pool * __percpu *pool;
2899 spin_lock_bh(&tcp_md5sig_pool_lock);
2900 pool = tcp_md5sig_pool;
2901 if (tcp_md5sig_users++ == 0) {
2903 spin_unlock_bh(&tcp_md5sig_pool_lock);
2906 spin_unlock_bh(&tcp_md5sig_pool_lock);
2910 spin_unlock_bh(&tcp_md5sig_pool_lock);
2913 /* we cannot hold spinlock here because this may sleep. */
2914 struct tcp_md5sig_pool * __percpu *p;
2916 p = __tcp_alloc_md5sig_pool(sk);
2917 spin_lock_bh(&tcp_md5sig_pool_lock);
2920 spin_unlock_bh(&tcp_md5sig_pool_lock);
2923 pool = tcp_md5sig_pool;
2925 /* oops, it has already been assigned. */
2926 spin_unlock_bh(&tcp_md5sig_pool_lock);
2927 __tcp_free_md5sig_pool(p);
2929 tcp_md5sig_pool = pool = p;
2930 spin_unlock_bh(&tcp_md5sig_pool_lock);
2936 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2938 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2940 struct tcp_md5sig_pool * __percpu *p;
2941 spin_lock_bh(&tcp_md5sig_pool_lock);
2942 p = tcp_md5sig_pool;
2945 spin_unlock_bh(&tcp_md5sig_pool_lock);
2946 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2949 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2951 void __tcp_put_md5sig_pool(void)
2953 tcp_free_md5sig_pool();
2956 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2958 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2961 struct scatterlist sg;
2964 __sum16 old_checksum = th->check;
2966 /* options aren't included in the hash */
2967 sg_init_one(&sg, th, sizeof(struct tcphdr));
2968 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2969 th->check = old_checksum;
2973 EXPORT_SYMBOL(tcp_md5_hash_header);
2975 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2976 struct sk_buff *skb, unsigned header_len)
2978 struct scatterlist sg;
2979 const struct tcphdr *tp = tcp_hdr(skb);
2980 struct hash_desc *desc = &hp->md5_desc;
2982 const unsigned head_data_len = skb_headlen(skb) > header_len ?
2983 skb_headlen(skb) - header_len : 0;
2984 const struct skb_shared_info *shi = skb_shinfo(skb);
2986 sg_init_table(&sg, 1);
2988 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2989 if (crypto_hash_update(desc, &sg, head_data_len))
2992 for (i = 0; i < shi->nr_frags; ++i) {
2993 const struct skb_frag_struct *f = &shi->frags[i];
2994 sg_set_page(&sg, f->page, f->size, f->page_offset);
2995 if (crypto_hash_update(desc, &sg, f->size))
3002 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3004 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3006 struct scatterlist sg;
3008 sg_init_one(&sg, key->key, key->keylen);
3009 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3012 EXPORT_SYMBOL(tcp_md5_hash_key);
3017 * Each Responder maintains up to two secret values concurrently for
3018 * efficient secret rollover. Each secret value has 4 states:
3020 * Generating. (tcp_secret_generating != tcp_secret_primary)
3021 * Generates new Responder-Cookies, but not yet used for primary
3022 * verification. This is a short-term state, typically lasting only
3023 * one round trip time (RTT).
3025 * Primary. (tcp_secret_generating == tcp_secret_primary)
3026 * Used both for generation and primary verification.
3028 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3029 * Used for verification, until the first failure that can be
3030 * verified by the newer Generating secret. At that time, this
3031 * cookie's state is changed to Secondary, and the Generating
3032 * cookie's state is changed to Primary. This is a short-term state,
3033 * typically lasting only one round trip time (RTT).
3035 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3036 * Used for secondary verification, after primary verification
3037 * failures. This state lasts no more than twice the Maximum Segment
3038 * Lifetime (2MSL). Then, the secret is discarded.
3040 struct tcp_cookie_secret {
3041 /* The secret is divided into two parts. The digest part is the
3042 * equivalent of previously hashing a secret and saving the state,
3043 * and serves as an initialization vector (IV). The message part
3044 * serves as the trailing secret.
3046 u32 secrets[COOKIE_WORKSPACE_WORDS];
3047 unsigned long expires;
3050 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3051 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3052 #define TCP_SECRET_LIFE (HZ * 600)
3054 static struct tcp_cookie_secret tcp_secret_one;
3055 static struct tcp_cookie_secret tcp_secret_two;
3057 /* Essentially a circular list, without dynamic allocation. */
3058 static struct tcp_cookie_secret *tcp_secret_generating;
3059 static struct tcp_cookie_secret *tcp_secret_primary;
3060 static struct tcp_cookie_secret *tcp_secret_retiring;
3061 static struct tcp_cookie_secret *tcp_secret_secondary;
3063 static DEFINE_SPINLOCK(tcp_secret_locker);
3065 /* Select a pseudo-random word in the cookie workspace.
3067 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3069 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3072 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3073 * Called in softirq context.
3074 * Returns: 0 for success.
3076 int tcp_cookie_generator(u32 *bakery)
3078 unsigned long jiffy = jiffies;
3080 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3081 spin_lock_bh(&tcp_secret_locker);
3082 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3083 /* refreshed by another */
3085 &tcp_secret_generating->secrets[0],
3086 COOKIE_WORKSPACE_WORDS);
3088 /* still needs refreshing */
3089 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3091 /* The first time, paranoia assumes that the
3092 * randomization function isn't as strong. But,
3093 * this secret initialization is delayed until
3094 * the last possible moment (packet arrival).
3095 * Although that time is observable, it is
3096 * unpredictably variable. Mash in the most
3097 * volatile clock bits available, and expire the
3098 * secret extra quickly.
3100 if (unlikely(tcp_secret_primary->expires ==
3101 tcp_secret_secondary->expires)) {
3104 getnstimeofday(&tv);
3105 bakery[COOKIE_DIGEST_WORDS+0] ^=
3108 tcp_secret_secondary->expires = jiffy
3110 + (0x0f & tcp_cookie_work(bakery, 0));
3112 tcp_secret_secondary->expires = jiffy
3114 + (0xff & tcp_cookie_work(bakery, 1));
3115 tcp_secret_primary->expires = jiffy
3117 + (0x1f & tcp_cookie_work(bakery, 2));
3119 memcpy(&tcp_secret_secondary->secrets[0],
3120 bakery, COOKIE_WORKSPACE_WORDS);
3122 rcu_assign_pointer(tcp_secret_generating,
3123 tcp_secret_secondary);
3124 rcu_assign_pointer(tcp_secret_retiring,
3125 tcp_secret_primary);
3127 * Neither call_rcu() nor synchronize_rcu() needed.
3128 * Retiring data is not freed. It is replaced after
3129 * further (locked) pointer updates, and a quiet time
3130 * (minimum 1MSL, maximum LIFE - 2MSL).
3133 spin_unlock_bh(&tcp_secret_locker);
3137 &rcu_dereference(tcp_secret_generating)->secrets[0],
3138 COOKIE_WORKSPACE_WORDS);
3139 rcu_read_unlock_bh();
3143 EXPORT_SYMBOL(tcp_cookie_generator);
3145 void tcp_done(struct sock *sk)
3147 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3148 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3150 tcp_set_state(sk, TCP_CLOSE);
3151 tcp_clear_xmit_timers(sk);
3153 sk->sk_shutdown = SHUTDOWN_MASK;
3155 if (!sock_flag(sk, SOCK_DEAD))
3156 sk->sk_state_change(sk);
3158 inet_csk_destroy_sock(sk);
3160 EXPORT_SYMBOL_GPL(tcp_done);
3162 extern struct tcp_congestion_ops tcp_reno;
3164 static __initdata unsigned long thash_entries;
3165 static int __init set_thash_entries(char *str)
3169 thash_entries = simple_strtoul(str, &str, 0);
3172 __setup("thash_entries=", set_thash_entries);
3174 void __init tcp_init(void)
3176 struct sk_buff *skb = NULL;
3177 unsigned long nr_pages, limit;
3178 int order, i, max_share;
3179 unsigned long jiffy = jiffies;
3181 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3183 percpu_counter_init(&tcp_sockets_allocated, 0);
3184 percpu_counter_init(&tcp_orphan_count, 0);
3185 tcp_hashinfo.bind_bucket_cachep =
3186 kmem_cache_create("tcp_bind_bucket",
3187 sizeof(struct inet_bind_bucket), 0,
3188 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3190 /* Size and allocate the main established and bind bucket
3193 * The methodology is similar to that of the buffer cache.
3195 tcp_hashinfo.ehash =
3196 alloc_large_system_hash("TCP established",
3197 sizeof(struct inet_ehash_bucket),
3199 (totalram_pages >= 128 * 1024) ?
3203 &tcp_hashinfo.ehash_mask,
3204 thash_entries ? 0 : 512 * 1024);
3205 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3206 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3207 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3209 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3210 panic("TCP: failed to alloc ehash_locks");
3211 tcp_hashinfo.bhash =
3212 alloc_large_system_hash("TCP bind",
3213 sizeof(struct inet_bind_hashbucket),
3214 tcp_hashinfo.ehash_mask + 1,
3215 (totalram_pages >= 128 * 1024) ?
3218 &tcp_hashinfo.bhash_size,
3221 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3222 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3223 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3224 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3227 /* Try to be a bit smarter and adjust defaults depending
3228 * on available memory.
3230 for (order = 0; ((1 << order) << PAGE_SHIFT) <
3231 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
3235 tcp_death_row.sysctl_max_tw_buckets = 180000;
3236 sysctl_tcp_max_orphans = 4096 << (order - 4);
3237 sysctl_max_syn_backlog = 1024;
3238 } else if (order < 3) {
3239 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
3240 sysctl_tcp_max_orphans >>= (3 - order);
3241 sysctl_max_syn_backlog = 128;
3244 /* Set the pressure threshold to be a fraction of global memory that
3245 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3246 * memory, with a floor of 128 pages.
3248 nr_pages = totalram_pages - totalhigh_pages;
3249 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3250 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3251 limit = max(limit, 128UL);
3252 sysctl_tcp_mem[0] = limit / 4 * 3;
3253 sysctl_tcp_mem[1] = limit;
3254 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3256 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3257 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3258 max_share = min(4UL*1024*1024, limit);
3260 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3261 sysctl_tcp_wmem[1] = 16*1024;
3262 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3264 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3265 sysctl_tcp_rmem[1] = 87380;
3266 sysctl_tcp_rmem[2] = max(87380, max_share);
3268 printk(KERN_INFO "TCP: Hash tables configured "
3269 "(established %u bind %u)\n",
3270 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3272 tcp_register_congestion_control(&tcp_reno);
3274 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3275 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3276 tcp_secret_one.expires = jiffy; /* past due */
3277 tcp_secret_two.expires = jiffy; /* past due */
3278 tcp_secret_generating = &tcp_secret_one;
3279 tcp_secret_primary = &tcp_secret_one;
3280 tcp_secret_retiring = &tcp_secret_two;
3281 tcp_secret_secondary = &tcp_secret_two;
3284 EXPORT_SYMBOL(tcp_close);
3285 EXPORT_SYMBOL(tcp_disconnect);
3286 EXPORT_SYMBOL(tcp_getsockopt);
3287 EXPORT_SYMBOL(tcp_ioctl);
3288 EXPORT_SYMBOL(tcp_poll);
3289 EXPORT_SYMBOL(tcp_read_sock);
3290 EXPORT_SYMBOL(tcp_recvmsg);
3291 EXPORT_SYMBOL(tcp_sendmsg);
3292 EXPORT_SYMBOL(tcp_splice_read);
3293 EXPORT_SYMBOL(tcp_sendpage);
3294 EXPORT_SYMBOL(tcp_setsockopt);
3295 EXPORT_SYMBOL(tcp_shutdown);