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).
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
57 * Alan Cox : Tidied tcp_data to avoid a potential
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
215 * Description of States:
217 * TCP_SYN_SENT sent a connection request, waiting for ack
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
222 * TCP_ESTABLISHED connection established
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
247 * TCP_CLOSE socket is finished
250 #include <linux/module.h>
251 #include <linux/types.h>
252 #include <linux/fcntl.h>
253 #include <linux/poll.h>
254 #include <linux/init.h>
255 #include <linux/smp_lock.h>
256 #include <linux/fs.h>
257 #include <linux/random.h>
258 #include <linux/bootmem.h>
259 #include <linux/cache.h>
260 #include <linux/err.h>
262 #include <net/icmp.h>
264 #include <net/xfrm.h>
266 #include <net/netdma.h>
268 #include <asm/uaccess.h>
269 #include <asm/ioctls.h>
271 int sysctl_tcp_fin_timeout __read_mostly
= TCP_FIN_TIMEOUT
;
273 DEFINE_SNMP_STAT(struct tcp_mib
, tcp_statistics
) __read_mostly
;
275 atomic_t tcp_orphan_count
= ATOMIC_INIT(0);
277 EXPORT_SYMBOL_GPL(tcp_orphan_count
);
279 int sysctl_tcp_mem
[3] __read_mostly
;
280 int sysctl_tcp_wmem
[3] __read_mostly
;
281 int sysctl_tcp_rmem
[3] __read_mostly
;
283 EXPORT_SYMBOL(sysctl_tcp_mem
);
284 EXPORT_SYMBOL(sysctl_tcp_rmem
);
285 EXPORT_SYMBOL(sysctl_tcp_wmem
);
287 atomic_t tcp_memory_allocated
; /* Current allocated memory. */
288 atomic_t tcp_sockets_allocated
; /* Current number of TCP sockets. */
290 EXPORT_SYMBOL(tcp_memory_allocated
);
291 EXPORT_SYMBOL(tcp_sockets_allocated
);
294 * Pressure flag: try to collapse.
295 * Technical note: it is used by multiple contexts non atomically.
296 * All the sk_stream_mem_schedule() is of this nature: accounting
297 * is strict, actions are advisory and have some latency.
299 int tcp_memory_pressure
;
301 EXPORT_SYMBOL(tcp_memory_pressure
);
303 void tcp_enter_memory_pressure(void)
305 if (!tcp_memory_pressure
) {
306 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES
);
307 tcp_memory_pressure
= 1;
311 EXPORT_SYMBOL(tcp_enter_memory_pressure
);
314 * Wait for a TCP event.
316 * Note that we don't need to lock the socket, as the upper poll layers
317 * take care of normal races (between the test and the event) and we don't
318 * go look at any of the socket buffers directly.
320 unsigned int tcp_poll(struct file
*file
, struct socket
*sock
, poll_table
*wait
)
323 struct sock
*sk
= sock
->sk
;
324 struct tcp_sock
*tp
= tcp_sk(sk
);
326 poll_wait(file
, sk
->sk_sleep
, wait
);
327 if (sk
->sk_state
== TCP_LISTEN
)
328 return inet_csk_listen_poll(sk
);
330 /* Socket is not locked. We are protected from async events
331 by poll logic and correct handling of state changes
332 made by another threads is impossible in any case.
340 * POLLHUP is certainly not done right. But poll() doesn't
341 * have a notion of HUP in just one direction, and for a
342 * socket the read side is more interesting.
344 * Some poll() documentation says that POLLHUP is incompatible
345 * with the POLLOUT/POLLWR flags, so somebody should check this
346 * all. But careful, it tends to be safer to return too many
347 * bits than too few, and you can easily break real applications
348 * if you don't tell them that something has hung up!
352 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
353 * our fs/select.c). It means that after we received EOF,
354 * poll always returns immediately, making impossible poll() on write()
355 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
356 * if and only if shutdown has been made in both directions.
357 * Actually, it is interesting to look how Solaris and DUX
358 * solve this dilemma. I would prefer, if PULLHUP were maskable,
359 * then we could set it on SND_SHUTDOWN. BTW examples given
360 * in Stevens' books assume exactly this behaviour, it explains
361 * why PULLHUP is incompatible with POLLOUT. --ANK
363 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
364 * blocking on fresh not-connected or disconnected socket. --ANK
366 if (sk
->sk_shutdown
== SHUTDOWN_MASK
|| sk
->sk_state
== TCP_CLOSE
)
368 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
369 mask
|= POLLIN
| POLLRDNORM
| POLLRDHUP
;
372 if ((1 << sk
->sk_state
) & ~(TCPF_SYN_SENT
| TCPF_SYN_RECV
)) {
373 /* Potential race condition. If read of tp below will
374 * escape above sk->sk_state, we can be illegally awaken
375 * in SYN_* states. */
376 if ((tp
->rcv_nxt
!= tp
->copied_seq
) &&
377 (tp
->urg_seq
!= tp
->copied_seq
||
378 tp
->rcv_nxt
!= tp
->copied_seq
+ 1 ||
379 sock_flag(sk
, SOCK_URGINLINE
) || !tp
->urg_data
))
380 mask
|= POLLIN
| POLLRDNORM
;
382 if (!(sk
->sk_shutdown
& SEND_SHUTDOWN
)) {
383 if (sk_stream_wspace(sk
) >= sk_stream_min_wspace(sk
)) {
384 mask
|= POLLOUT
| POLLWRNORM
;
385 } else { /* send SIGIO later */
386 set_bit(SOCK_ASYNC_NOSPACE
,
387 &sk
->sk_socket
->flags
);
388 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
390 /* Race breaker. If space is freed after
391 * wspace test but before the flags are set,
392 * IO signal will be lost.
394 if (sk_stream_wspace(sk
) >= sk_stream_min_wspace(sk
))
395 mask
|= POLLOUT
| POLLWRNORM
;
399 if (tp
->urg_data
& TCP_URG_VALID
)
405 int tcp_ioctl(struct sock
*sk
, int cmd
, unsigned long arg
)
407 struct tcp_sock
*tp
= tcp_sk(sk
);
412 if (sk
->sk_state
== TCP_LISTEN
)
416 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
))
418 else if (sock_flag(sk
, SOCK_URGINLINE
) ||
420 before(tp
->urg_seq
, tp
->copied_seq
) ||
421 !before(tp
->urg_seq
, tp
->rcv_nxt
)) {
422 answ
= tp
->rcv_nxt
- tp
->copied_seq
;
424 /* Subtract 1, if FIN is in queue. */
425 if (answ
&& !skb_queue_empty(&sk
->sk_receive_queue
))
427 ((struct sk_buff
*)sk
->sk_receive_queue
.prev
)->h
.th
->fin
;
429 answ
= tp
->urg_seq
- tp
->copied_seq
;
433 answ
= tp
->urg_data
&& tp
->urg_seq
== tp
->copied_seq
;
436 if (sk
->sk_state
== TCP_LISTEN
)
439 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
))
442 answ
= tp
->write_seq
- tp
->snd_una
;
448 return put_user(answ
, (int __user
*)arg
);
451 static inline void tcp_mark_push(struct tcp_sock
*tp
, struct sk_buff
*skb
)
453 TCP_SKB_CB(skb
)->flags
|= TCPCB_FLAG_PSH
;
454 tp
->pushed_seq
= tp
->write_seq
;
457 static inline int forced_push(struct tcp_sock
*tp
)
459 return after(tp
->write_seq
, tp
->pushed_seq
+ (tp
->max_window
>> 1));
462 static inline void skb_entail(struct sock
*sk
, struct tcp_sock
*tp
,
466 TCP_SKB_CB(skb
)->seq
= tp
->write_seq
;
467 TCP_SKB_CB(skb
)->end_seq
= tp
->write_seq
;
468 TCP_SKB_CB(skb
)->flags
= TCPCB_FLAG_ACK
;
469 TCP_SKB_CB(skb
)->sacked
= 0;
470 skb_header_release(skb
);
471 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
472 sk_charge_skb(sk
, skb
);
473 if (!sk
->sk_send_head
)
474 sk
->sk_send_head
= skb
;
475 if (tp
->nonagle
& TCP_NAGLE_PUSH
)
476 tp
->nonagle
&= ~TCP_NAGLE_PUSH
;
479 static inline void tcp_mark_urg(struct tcp_sock
*tp
, int flags
,
482 if (flags
& MSG_OOB
) {
484 tp
->snd_up
= tp
->write_seq
;
485 TCP_SKB_CB(skb
)->sacked
|= TCPCB_URG
;
489 static inline void tcp_push(struct sock
*sk
, struct tcp_sock
*tp
, int flags
,
490 int mss_now
, int nonagle
)
492 if (sk
->sk_send_head
) {
493 struct sk_buff
*skb
= sk
->sk_write_queue
.prev
;
494 if (!(flags
& MSG_MORE
) || forced_push(tp
))
495 tcp_mark_push(tp
, skb
);
496 tcp_mark_urg(tp
, flags
, skb
);
497 __tcp_push_pending_frames(sk
, tp
, mss_now
,
498 (flags
& MSG_MORE
) ? TCP_NAGLE_CORK
: nonagle
);
502 static ssize_t
do_tcp_sendpages(struct sock
*sk
, struct page
**pages
, int poffset
,
503 size_t psize
, int flags
)
505 struct tcp_sock
*tp
= tcp_sk(sk
);
506 int mss_now
, size_goal
;
509 long timeo
= sock_sndtimeo(sk
, flags
& MSG_DONTWAIT
);
511 /* Wait for a connection to finish. */
512 if ((1 << sk
->sk_state
) & ~(TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
))
513 if ((err
= sk_stream_wait_connect(sk
, &timeo
)) != 0)
516 clear_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
518 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
519 size_goal
= tp
->xmit_size_goal
;
523 if (sk
->sk_err
|| (sk
->sk_shutdown
& SEND_SHUTDOWN
))
527 struct sk_buff
*skb
= sk
->sk_write_queue
.prev
;
528 struct page
*page
= pages
[poffset
/ PAGE_SIZE
];
529 int copy
, i
, can_coalesce
;
530 int offset
= poffset
% PAGE_SIZE
;
531 int size
= min_t(size_t, psize
, PAGE_SIZE
- offset
);
533 if (!sk
->sk_send_head
|| (copy
= size_goal
- skb
->len
) <= 0) {
535 if (!sk_stream_memory_free(sk
))
536 goto wait_for_sndbuf
;
538 skb
= sk_stream_alloc_pskb(sk
, 0, 0,
541 goto wait_for_memory
;
543 skb_entail(sk
, tp
, skb
);
550 i
= skb_shinfo(skb
)->nr_frags
;
551 can_coalesce
= skb_can_coalesce(skb
, i
, page
, offset
);
552 if (!can_coalesce
&& i
>= MAX_SKB_FRAGS
) {
553 tcp_mark_push(tp
, skb
);
556 if (!sk_stream_wmem_schedule(sk
, copy
))
557 goto wait_for_memory
;
560 skb_shinfo(skb
)->frags
[i
- 1].size
+= copy
;
563 skb_fill_page_desc(skb
, i
, page
, offset
, copy
);
567 skb
->data_len
+= copy
;
568 skb
->truesize
+= copy
;
569 sk
->sk_wmem_queued
+= copy
;
570 sk
->sk_forward_alloc
-= copy
;
571 skb
->ip_summed
= CHECKSUM_PARTIAL
;
572 tp
->write_seq
+= copy
;
573 TCP_SKB_CB(skb
)->end_seq
+= copy
;
574 skb_shinfo(skb
)->gso_segs
= 0;
577 TCP_SKB_CB(skb
)->flags
&= ~TCPCB_FLAG_PSH
;
581 if (!(psize
-= copy
))
584 if (skb
->len
< mss_now
|| (flags
& MSG_OOB
))
587 if (forced_push(tp
)) {
588 tcp_mark_push(tp
, skb
);
589 __tcp_push_pending_frames(sk
, tp
, mss_now
, TCP_NAGLE_PUSH
);
590 } else if (skb
== sk
->sk_send_head
)
591 tcp_push_one(sk
, mss_now
);
595 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
598 tcp_push(sk
, tp
, flags
& ~MSG_MORE
, mss_now
, TCP_NAGLE_PUSH
);
600 if ((err
= sk_stream_wait_memory(sk
, &timeo
)) != 0)
603 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
604 size_goal
= tp
->xmit_size_goal
;
609 tcp_push(sk
, tp
, flags
, mss_now
, tp
->nonagle
);
616 return sk_stream_error(sk
, flags
, err
);
619 ssize_t
tcp_sendpage(struct socket
*sock
, struct page
*page
, int offset
,
620 size_t size
, int flags
)
623 struct sock
*sk
= sock
->sk
;
625 if (!(sk
->sk_route_caps
& NETIF_F_SG
) ||
626 !(sk
->sk_route_caps
& NETIF_F_ALL_CSUM
))
627 return sock_no_sendpage(sock
, page
, offset
, size
, flags
);
631 res
= do_tcp_sendpages(sk
, &page
, offset
, size
, flags
);
637 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
638 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
640 static inline int select_size(struct sock
*sk
, struct tcp_sock
*tp
)
642 int tmp
= tp
->mss_cache
;
644 if (sk
->sk_route_caps
& NETIF_F_SG
) {
648 int pgbreak
= SKB_MAX_HEAD(MAX_TCP_HEADER
);
650 if (tmp
>= pgbreak
&&
651 tmp
<= pgbreak
+ (MAX_SKB_FRAGS
- 1) * PAGE_SIZE
)
659 int tcp_sendmsg(struct kiocb
*iocb
, struct sock
*sk
, struct msghdr
*msg
,
663 struct tcp_sock
*tp
= tcp_sk(sk
);
666 int mss_now
, size_goal
;
673 flags
= msg
->msg_flags
;
674 timeo
= sock_sndtimeo(sk
, flags
& MSG_DONTWAIT
);
676 /* Wait for a connection to finish. */
677 if ((1 << sk
->sk_state
) & ~(TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
))
678 if ((err
= sk_stream_wait_connect(sk
, &timeo
)) != 0)
681 /* This should be in poll */
682 clear_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
684 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
685 size_goal
= tp
->xmit_size_goal
;
687 /* Ok commence sending. */
688 iovlen
= msg
->msg_iovlen
;
693 if (sk
->sk_err
|| (sk
->sk_shutdown
& SEND_SHUTDOWN
))
696 while (--iovlen
>= 0) {
697 int seglen
= iov
->iov_len
;
698 unsigned char __user
*from
= iov
->iov_base
;
705 skb
= sk
->sk_write_queue
.prev
;
707 if (!sk
->sk_send_head
||
708 (copy
= size_goal
- skb
->len
) <= 0) {
711 /* Allocate new segment. If the interface is SG,
712 * allocate skb fitting to single page.
714 if (!sk_stream_memory_free(sk
))
715 goto wait_for_sndbuf
;
717 skb
= sk_stream_alloc_pskb(sk
, select_size(sk
, tp
),
718 0, sk
->sk_allocation
);
720 goto wait_for_memory
;
723 * Check whether we can use HW checksum.
725 if (sk
->sk_route_caps
& NETIF_F_ALL_CSUM
)
726 skb
->ip_summed
= CHECKSUM_PARTIAL
;
728 skb_entail(sk
, tp
, skb
);
732 /* Try to append data to the end of skb. */
736 /* Where to copy to? */
737 if (skb_tailroom(skb
) > 0) {
738 /* We have some space in skb head. Superb! */
739 if (copy
> skb_tailroom(skb
))
740 copy
= skb_tailroom(skb
);
741 if ((err
= skb_add_data(skb
, from
, copy
)) != 0)
745 int i
= skb_shinfo(skb
)->nr_frags
;
746 struct page
*page
= TCP_PAGE(sk
);
747 int off
= TCP_OFF(sk
);
749 if (skb_can_coalesce(skb
, i
, page
, off
) &&
751 /* We can extend the last page
754 } else if (i
== MAX_SKB_FRAGS
||
756 !(sk
->sk_route_caps
& NETIF_F_SG
))) {
757 /* Need to add new fragment and cannot
758 * do this because interface is non-SG,
759 * or because all the page slots are
761 tcp_mark_push(tp
, skb
);
764 if (off
== PAGE_SIZE
) {
766 TCP_PAGE(sk
) = page
= NULL
;
772 if (copy
> PAGE_SIZE
- off
)
773 copy
= PAGE_SIZE
- off
;
775 if (!sk_stream_wmem_schedule(sk
, copy
))
776 goto wait_for_memory
;
779 /* Allocate new cache page. */
780 if (!(page
= sk_stream_alloc_page(sk
)))
781 goto wait_for_memory
;
784 /* Time to copy data. We are close to
786 err
= skb_copy_to_page(sk
, from
, skb
, page
,
789 /* If this page was new, give it to the
790 * socket so it does not get leaked.
799 /* Update the skb. */
801 skb_shinfo(skb
)->frags
[i
- 1].size
+=
804 skb_fill_page_desc(skb
, i
, page
, off
, copy
);
807 } else if (off
+ copy
< PAGE_SIZE
) {
813 TCP_OFF(sk
) = off
+ copy
;
817 TCP_SKB_CB(skb
)->flags
&= ~TCPCB_FLAG_PSH
;
819 tp
->write_seq
+= copy
;
820 TCP_SKB_CB(skb
)->end_seq
+= copy
;
821 skb_shinfo(skb
)->gso_segs
= 0;
825 if ((seglen
-= copy
) == 0 && iovlen
== 0)
828 if (skb
->len
< mss_now
|| (flags
& MSG_OOB
))
831 if (forced_push(tp
)) {
832 tcp_mark_push(tp
, skb
);
833 __tcp_push_pending_frames(sk
, tp
, mss_now
, TCP_NAGLE_PUSH
);
834 } else if (skb
== sk
->sk_send_head
)
835 tcp_push_one(sk
, mss_now
);
839 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
842 tcp_push(sk
, tp
, flags
& ~MSG_MORE
, mss_now
, TCP_NAGLE_PUSH
);
844 if ((err
= sk_stream_wait_memory(sk
, &timeo
)) != 0)
847 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
848 size_goal
= tp
->xmit_size_goal
;
854 tcp_push(sk
, tp
, flags
, mss_now
, tp
->nonagle
);
861 if (sk
->sk_send_head
== skb
)
862 sk
->sk_send_head
= NULL
;
863 __skb_unlink(skb
, &sk
->sk_write_queue
);
864 sk_stream_free_skb(sk
, skb
);
871 err
= sk_stream_error(sk
, flags
, err
);
878 * Handle reading urgent data. BSD has very simple semantics for
879 * this, no blocking and very strange errors 8)
882 static int tcp_recv_urg(struct sock
*sk
, long timeo
,
883 struct msghdr
*msg
, int len
, int flags
,
886 struct tcp_sock
*tp
= tcp_sk(sk
);
888 /* No URG data to read. */
889 if (sock_flag(sk
, SOCK_URGINLINE
) || !tp
->urg_data
||
890 tp
->urg_data
== TCP_URG_READ
)
891 return -EINVAL
; /* Yes this is right ! */
893 if (sk
->sk_state
== TCP_CLOSE
&& !sock_flag(sk
, SOCK_DONE
))
896 if (tp
->urg_data
& TCP_URG_VALID
) {
898 char c
= tp
->urg_data
;
900 if (!(flags
& MSG_PEEK
))
901 tp
->urg_data
= TCP_URG_READ
;
903 /* Read urgent data. */
904 msg
->msg_flags
|= MSG_OOB
;
907 if (!(flags
& MSG_TRUNC
))
908 err
= memcpy_toiovec(msg
->msg_iov
, &c
, 1);
911 msg
->msg_flags
|= MSG_TRUNC
;
913 return err
? -EFAULT
: len
;
916 if (sk
->sk_state
== TCP_CLOSE
|| (sk
->sk_shutdown
& RCV_SHUTDOWN
))
919 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
920 * the available implementations agree in this case:
921 * this call should never block, independent of the
922 * blocking state of the socket.
923 * Mike <pall@rz.uni-karlsruhe.de>
928 /* Clean up the receive buffer for full frames taken by the user,
929 * then send an ACK if necessary. COPIED is the number of bytes
930 * tcp_recvmsg has given to the user so far, it speeds up the
931 * calculation of whether or not we must ACK for the sake of
934 void tcp_cleanup_rbuf(struct sock
*sk
, int copied
)
936 struct tcp_sock
*tp
= tcp_sk(sk
);
940 struct sk_buff
*skb
= skb_peek(&sk
->sk_receive_queue
);
942 BUG_TRAP(!skb
|| before(tp
->copied_seq
, TCP_SKB_CB(skb
)->end_seq
));
945 if (inet_csk_ack_scheduled(sk
)) {
946 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
947 /* Delayed ACKs frequently hit locked sockets during bulk
949 if (icsk
->icsk_ack
.blocked
||
950 /* Once-per-two-segments ACK was not sent by tcp_input.c */
951 tp
->rcv_nxt
- tp
->rcv_wup
> icsk
->icsk_ack
.rcv_mss
||
953 * If this read emptied read buffer, we send ACK, if
954 * connection is not bidirectional, user drained
955 * receive buffer and there was a small segment
959 ((icsk
->icsk_ack
.pending
& ICSK_ACK_PUSHED2
) ||
960 ((icsk
->icsk_ack
.pending
& ICSK_ACK_PUSHED
) &&
961 !icsk
->icsk_ack
.pingpong
)) &&
962 !atomic_read(&sk
->sk_rmem_alloc
)))
966 /* We send an ACK if we can now advertise a non-zero window
967 * which has been raised "significantly".
969 * Even if window raised up to infinity, do not send window open ACK
970 * in states, where we will not receive more. It is useless.
972 if (copied
> 0 && !time_to_ack
&& !(sk
->sk_shutdown
& RCV_SHUTDOWN
)) {
973 __u32 rcv_window_now
= tcp_receive_window(tp
);
975 /* Optimize, __tcp_select_window() is not cheap. */
976 if (2*rcv_window_now
<= tp
->window_clamp
) {
977 __u32 new_window
= __tcp_select_window(sk
);
979 /* Send ACK now, if this read freed lots of space
980 * in our buffer. Certainly, new_window is new window.
981 * We can advertise it now, if it is not less than current one.
982 * "Lots" means "at least twice" here.
984 if (new_window
&& new_window
>= 2 * rcv_window_now
)
992 static void tcp_prequeue_process(struct sock
*sk
)
995 struct tcp_sock
*tp
= tcp_sk(sk
);
997 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED
);
999 /* RX process wants to run with disabled BHs, though it is not
1002 while ((skb
= __skb_dequeue(&tp
->ucopy
.prequeue
)) != NULL
)
1003 sk
->sk_backlog_rcv(sk
, skb
);
1006 /* Clear memory counter. */
1007 tp
->ucopy
.memory
= 0;
1010 static inline struct sk_buff
*tcp_recv_skb(struct sock
*sk
, u32 seq
, u32
*off
)
1012 struct sk_buff
*skb
;
1015 skb_queue_walk(&sk
->sk_receive_queue
, skb
) {
1016 offset
= seq
- TCP_SKB_CB(skb
)->seq
;
1019 if (offset
< skb
->len
|| skb
->h
.th
->fin
) {
1028 * This routine provides an alternative to tcp_recvmsg() for routines
1029 * that would like to handle copying from skbuffs directly in 'sendfile'
1032 * - It is assumed that the socket was locked by the caller.
1033 * - The routine does not block.
1034 * - At present, there is no support for reading OOB data
1035 * or for 'peeking' the socket using this routine
1036 * (although both would be easy to implement).
1038 int tcp_read_sock(struct sock
*sk
, read_descriptor_t
*desc
,
1039 sk_read_actor_t recv_actor
)
1041 struct sk_buff
*skb
;
1042 struct tcp_sock
*tp
= tcp_sk(sk
);
1043 u32 seq
= tp
->copied_seq
;
1047 if (sk
->sk_state
== TCP_LISTEN
)
1049 while ((skb
= tcp_recv_skb(sk
, seq
, &offset
)) != NULL
) {
1050 if (offset
< skb
->len
) {
1053 len
= skb
->len
- offset
;
1054 /* Stop reading if we hit a patch of urgent data */
1056 u32 urg_offset
= tp
->urg_seq
- seq
;
1057 if (urg_offset
< len
)
1062 used
= recv_actor(desc
, skb
, offset
, len
);
1068 if (offset
!= skb
->len
)
1071 if (skb
->h
.th
->fin
) {
1072 sk_eat_skb(sk
, skb
, 0);
1076 sk_eat_skb(sk
, skb
, 0);
1080 tp
->copied_seq
= seq
;
1082 tcp_rcv_space_adjust(sk
);
1084 /* Clean up data we have read: This will do ACK frames. */
1086 tcp_cleanup_rbuf(sk
, copied
);
1091 * This routine copies from a sock struct into the user buffer.
1093 * Technical note: in 2.3 we work on _locked_ socket, so that
1094 * tricks with *seq access order and skb->users are not required.
1095 * Probably, code can be easily improved even more.
1098 int tcp_recvmsg(struct kiocb
*iocb
, struct sock
*sk
, struct msghdr
*msg
,
1099 size_t len
, int nonblock
, int flags
, int *addr_len
)
1101 struct tcp_sock
*tp
= tcp_sk(sk
);
1107 int target
; /* Read at least this many bytes */
1109 struct task_struct
*user_recv
= NULL
;
1110 int copied_early
= 0;
1114 TCP_CHECK_TIMER(sk
);
1117 if (sk
->sk_state
== TCP_LISTEN
)
1120 timeo
= sock_rcvtimeo(sk
, nonblock
);
1122 /* Urgent data needs to be handled specially. */
1123 if (flags
& MSG_OOB
)
1126 seq
= &tp
->copied_seq
;
1127 if (flags
& MSG_PEEK
) {
1128 peek_seq
= tp
->copied_seq
;
1132 target
= sock_rcvlowat(sk
, flags
& MSG_WAITALL
, len
);
1134 #ifdef CONFIG_NET_DMA
1135 tp
->ucopy
.dma_chan
= NULL
;
1137 if ((len
> sysctl_tcp_dma_copybreak
) && !(flags
& MSG_PEEK
) &&
1138 !sysctl_tcp_low_latency
&& __get_cpu_var(softnet_data
).net_dma
) {
1139 preempt_enable_no_resched();
1140 tp
->ucopy
.pinned_list
= dma_pin_iovec_pages(msg
->msg_iov
, len
);
1142 preempt_enable_no_resched();
1146 struct sk_buff
*skb
;
1149 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1150 if (tp
->urg_data
&& tp
->urg_seq
== *seq
) {
1153 if (signal_pending(current
)) {
1154 copied
= timeo
? sock_intr_errno(timeo
) : -EAGAIN
;
1159 /* Next get a buffer. */
1161 skb
= skb_peek(&sk
->sk_receive_queue
);
1166 /* Now that we have two receive queues this
1169 if (before(*seq
, TCP_SKB_CB(skb
)->seq
)) {
1170 printk(KERN_INFO
"recvmsg bug: copied %X "
1171 "seq %X\n", *seq
, TCP_SKB_CB(skb
)->seq
);
1174 offset
= *seq
- TCP_SKB_CB(skb
)->seq
;
1177 if (offset
< skb
->len
)
1181 BUG_TRAP(flags
& MSG_PEEK
);
1183 } while (skb
!= (struct sk_buff
*)&sk
->sk_receive_queue
);
1185 /* Well, if we have backlog, try to process it now yet. */
1187 if (copied
>= target
&& !sk
->sk_backlog
.tail
)
1192 sk
->sk_state
== TCP_CLOSE
||
1193 (sk
->sk_shutdown
& RCV_SHUTDOWN
) ||
1195 signal_pending(current
) ||
1199 if (sock_flag(sk
, SOCK_DONE
))
1203 copied
= sock_error(sk
);
1207 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
1210 if (sk
->sk_state
== TCP_CLOSE
) {
1211 if (!sock_flag(sk
, SOCK_DONE
)) {
1212 /* This occurs when user tries to read
1213 * from never connected socket.
1226 if (signal_pending(current
)) {
1227 copied
= sock_intr_errno(timeo
);
1232 tcp_cleanup_rbuf(sk
, copied
);
1234 if (!sysctl_tcp_low_latency
&& tp
->ucopy
.task
== user_recv
) {
1235 /* Install new reader */
1236 if (!user_recv
&& !(flags
& (MSG_TRUNC
| MSG_PEEK
))) {
1237 user_recv
= current
;
1238 tp
->ucopy
.task
= user_recv
;
1239 tp
->ucopy
.iov
= msg
->msg_iov
;
1242 tp
->ucopy
.len
= len
;
1244 BUG_TRAP(tp
->copied_seq
== tp
->rcv_nxt
||
1245 (flags
& (MSG_PEEK
| MSG_TRUNC
)));
1247 /* Ugly... If prequeue is not empty, we have to
1248 * process it before releasing socket, otherwise
1249 * order will be broken at second iteration.
1250 * More elegant solution is required!!!
1252 * Look: we have the following (pseudo)queues:
1254 * 1. packets in flight
1259 * Each queue can be processed only if the next ones
1260 * are empty. At this point we have empty receive_queue.
1261 * But prequeue _can_ be not empty after 2nd iteration,
1262 * when we jumped to start of loop because backlog
1263 * processing added something to receive_queue.
1264 * We cannot release_sock(), because backlog contains
1265 * packets arrived _after_ prequeued ones.
1267 * Shortly, algorithm is clear --- to process all
1268 * the queues in order. We could make it more directly,
1269 * requeueing packets from backlog to prequeue, if
1270 * is not empty. It is more elegant, but eats cycles,
1273 if (!skb_queue_empty(&tp
->ucopy
.prequeue
))
1276 /* __ Set realtime policy in scheduler __ */
1279 if (copied
>= target
) {
1280 /* Do not sleep, just process backlog. */
1284 sk_wait_data(sk
, &timeo
);
1286 #ifdef CONFIG_NET_DMA
1287 tp
->ucopy
.wakeup
= 0;
1293 /* __ Restore normal policy in scheduler __ */
1295 if ((chunk
= len
- tp
->ucopy
.len
) != 0) {
1296 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG
, chunk
);
1301 if (tp
->rcv_nxt
== tp
->copied_seq
&&
1302 !skb_queue_empty(&tp
->ucopy
.prequeue
)) {
1304 tcp_prequeue_process(sk
);
1306 if ((chunk
= len
- tp
->ucopy
.len
) != 0) {
1307 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE
, chunk
);
1313 if ((flags
& MSG_PEEK
) && peek_seq
!= tp
->copied_seq
) {
1314 if (net_ratelimit())
1315 printk(KERN_DEBUG
"TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1316 current
->comm
, current
->pid
);
1317 peek_seq
= tp
->copied_seq
;
1322 /* Ok so how much can we use? */
1323 used
= skb
->len
- offset
;
1327 /* Do we have urgent data here? */
1329 u32 urg_offset
= tp
->urg_seq
- *seq
;
1330 if (urg_offset
< used
) {
1332 if (!sock_flag(sk
, SOCK_URGINLINE
)) {
1344 if (!(flags
& MSG_TRUNC
)) {
1345 #ifdef CONFIG_NET_DMA
1346 if (!tp
->ucopy
.dma_chan
&& tp
->ucopy
.pinned_list
)
1347 tp
->ucopy
.dma_chan
= get_softnet_dma();
1349 if (tp
->ucopy
.dma_chan
) {
1350 tp
->ucopy
.dma_cookie
= dma_skb_copy_datagram_iovec(
1351 tp
->ucopy
.dma_chan
, skb
, offset
,
1353 tp
->ucopy
.pinned_list
);
1355 if (tp
->ucopy
.dma_cookie
< 0) {
1357 printk(KERN_ALERT
"dma_cookie < 0\n");
1359 /* Exception. Bailout! */
1364 if ((offset
+ used
) == skb
->len
)
1370 err
= skb_copy_datagram_iovec(skb
, offset
,
1371 msg
->msg_iov
, used
);
1373 /* Exception. Bailout! */
1385 tcp_rcv_space_adjust(sk
);
1388 if (tp
->urg_data
&& after(tp
->copied_seq
, tp
->urg_seq
)) {
1390 tcp_fast_path_check(sk
, tp
);
1392 if (used
+ offset
< skb
->len
)
1397 if (!(flags
& MSG_PEEK
)) {
1398 sk_eat_skb(sk
, skb
, copied_early
);
1404 /* Process the FIN. */
1406 if (!(flags
& MSG_PEEK
)) {
1407 sk_eat_skb(sk
, skb
, copied_early
);
1414 if (!skb_queue_empty(&tp
->ucopy
.prequeue
)) {
1417 tp
->ucopy
.len
= copied
> 0 ? len
: 0;
1419 tcp_prequeue_process(sk
);
1421 if (copied
> 0 && (chunk
= len
- tp
->ucopy
.len
) != 0) {
1422 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE
, chunk
);
1428 tp
->ucopy
.task
= NULL
;
1432 #ifdef CONFIG_NET_DMA
1433 if (tp
->ucopy
.dma_chan
) {
1434 struct sk_buff
*skb
;
1435 dma_cookie_t done
, used
;
1437 dma_async_memcpy_issue_pending(tp
->ucopy
.dma_chan
);
1439 while (dma_async_memcpy_complete(tp
->ucopy
.dma_chan
,
1440 tp
->ucopy
.dma_cookie
, &done
,
1441 &used
) == DMA_IN_PROGRESS
) {
1442 /* do partial cleanup of sk_async_wait_queue */
1443 while ((skb
= skb_peek(&sk
->sk_async_wait_queue
)) &&
1444 (dma_async_is_complete(skb
->dma_cookie
, done
,
1445 used
) == DMA_SUCCESS
)) {
1446 __skb_dequeue(&sk
->sk_async_wait_queue
);
1451 /* Safe to free early-copied skbs now */
1452 __skb_queue_purge(&sk
->sk_async_wait_queue
);
1453 dma_chan_put(tp
->ucopy
.dma_chan
);
1454 tp
->ucopy
.dma_chan
= NULL
;
1456 if (tp
->ucopy
.pinned_list
) {
1457 dma_unpin_iovec_pages(tp
->ucopy
.pinned_list
);
1458 tp
->ucopy
.pinned_list
= NULL
;
1462 /* According to UNIX98, msg_name/msg_namelen are ignored
1463 * on connected socket. I was just happy when found this 8) --ANK
1466 /* Clean up data we have read: This will do ACK frames. */
1467 tcp_cleanup_rbuf(sk
, copied
);
1469 TCP_CHECK_TIMER(sk
);
1474 TCP_CHECK_TIMER(sk
);
1479 err
= tcp_recv_urg(sk
, timeo
, msg
, len
, flags
, addr_len
);
1484 * State processing on a close. This implements the state shift for
1485 * sending our FIN frame. Note that we only send a FIN for some
1486 * states. A shutdown() may have already sent the FIN, or we may be
1490 static const unsigned char new_state
[16] = {
1491 /* current state: new state: action: */
1492 /* (Invalid) */ TCP_CLOSE
,
1493 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1
| TCP_ACTION_FIN
,
1494 /* TCP_SYN_SENT */ TCP_CLOSE
,
1495 /* TCP_SYN_RECV */ TCP_FIN_WAIT1
| TCP_ACTION_FIN
,
1496 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1
,
1497 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2
,
1498 /* TCP_TIME_WAIT */ TCP_CLOSE
,
1499 /* TCP_CLOSE */ TCP_CLOSE
,
1500 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK
| TCP_ACTION_FIN
,
1501 /* TCP_LAST_ACK */ TCP_LAST_ACK
,
1502 /* TCP_LISTEN */ TCP_CLOSE
,
1503 /* TCP_CLOSING */ TCP_CLOSING
,
1506 static int tcp_close_state(struct sock
*sk
)
1508 int next
= (int)new_state
[sk
->sk_state
];
1509 int ns
= next
& TCP_STATE_MASK
;
1511 tcp_set_state(sk
, ns
);
1513 return next
& TCP_ACTION_FIN
;
1517 * Shutdown the sending side of a connection. Much like close except
1518 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1521 void tcp_shutdown(struct sock
*sk
, int how
)
1523 /* We need to grab some memory, and put together a FIN,
1524 * and then put it into the queue to be sent.
1525 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1527 if (!(how
& SEND_SHUTDOWN
))
1530 /* If we've already sent a FIN, or it's a closed state, skip this. */
1531 if ((1 << sk
->sk_state
) &
1532 (TCPF_ESTABLISHED
| TCPF_SYN_SENT
|
1533 TCPF_SYN_RECV
| TCPF_CLOSE_WAIT
)) {
1534 /* Clear out any half completed packets. FIN if needed. */
1535 if (tcp_close_state(sk
))
1540 void tcp_close(struct sock
*sk
, long timeout
)
1542 struct sk_buff
*skb
;
1543 int data_was_unread
= 0;
1547 sk
->sk_shutdown
= SHUTDOWN_MASK
;
1549 if (sk
->sk_state
== TCP_LISTEN
) {
1550 tcp_set_state(sk
, TCP_CLOSE
);
1553 inet_csk_listen_stop(sk
);
1555 goto adjudge_to_death
;
1558 /* We need to flush the recv. buffs. We do this only on the
1559 * descriptor close, not protocol-sourced closes, because the
1560 * reader process may not have drained the data yet!
1562 while ((skb
= __skb_dequeue(&sk
->sk_receive_queue
)) != NULL
) {
1563 u32 len
= TCP_SKB_CB(skb
)->end_seq
- TCP_SKB_CB(skb
)->seq
-
1565 data_was_unread
+= len
;
1569 sk_stream_mem_reclaim(sk
);
1571 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1572 * 3.10, we send a RST here because data was lost. To
1573 * witness the awful effects of the old behavior of always
1574 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1575 * a bulk GET in an FTP client, suspend the process, wait
1576 * for the client to advertise a zero window, then kill -9
1577 * the FTP client, wheee... Note: timeout is always zero
1580 if (data_was_unread
) {
1581 /* Unread data was tossed, zap the connection. */
1582 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE
);
1583 tcp_set_state(sk
, TCP_CLOSE
);
1584 tcp_send_active_reset(sk
, GFP_KERNEL
);
1585 } else if (sock_flag(sk
, SOCK_LINGER
) && !sk
->sk_lingertime
) {
1586 /* Check zero linger _after_ checking for unread data. */
1587 sk
->sk_prot
->disconnect(sk
, 0);
1588 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA
);
1589 } else if (tcp_close_state(sk
)) {
1590 /* We FIN if the application ate all the data before
1591 * zapping the connection.
1594 /* RED-PEN. Formally speaking, we have broken TCP state
1595 * machine. State transitions:
1597 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1598 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1599 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1601 * are legal only when FIN has been sent (i.e. in window),
1602 * rather than queued out of window. Purists blame.
1604 * F.e. "RFC state" is ESTABLISHED,
1605 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1607 * The visible declinations are that sometimes
1608 * we enter time-wait state, when it is not required really
1609 * (harmless), do not send active resets, when they are
1610 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1611 * they look as CLOSING or LAST_ACK for Linux)
1612 * Probably, I missed some more holelets.
1618 sk_stream_wait_close(sk
, timeout
);
1621 state
= sk
->sk_state
;
1624 atomic_inc(sk
->sk_prot
->orphan_count
);
1626 /* It is the last release_sock in its life. It will remove backlog. */
1630 /* Now socket is owned by kernel and we acquire BH lock
1631 to finish close. No need to check for user refs.
1635 BUG_TRAP(!sock_owned_by_user(sk
));
1637 /* Have we already been destroyed by a softirq or backlog? */
1638 if (state
!= TCP_CLOSE
&& sk
->sk_state
== TCP_CLOSE
)
1641 /* This is a (useful) BSD violating of the RFC. There is a
1642 * problem with TCP as specified in that the other end could
1643 * keep a socket open forever with no application left this end.
1644 * We use a 3 minute timeout (about the same as BSD) then kill
1645 * our end. If they send after that then tough - BUT: long enough
1646 * that we won't make the old 4*rto = almost no time - whoops
1649 * Nope, it was not mistake. It is really desired behaviour
1650 * f.e. on http servers, when such sockets are useless, but
1651 * consume significant resources. Let's do it with special
1652 * linger2 option. --ANK
1655 if (sk
->sk_state
== TCP_FIN_WAIT2
) {
1656 struct tcp_sock
*tp
= tcp_sk(sk
);
1657 if (tp
->linger2
< 0) {
1658 tcp_set_state(sk
, TCP_CLOSE
);
1659 tcp_send_active_reset(sk
, GFP_ATOMIC
);
1660 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER
);
1662 const int tmo
= tcp_fin_time(sk
);
1664 if (tmo
> TCP_TIMEWAIT_LEN
) {
1665 inet_csk_reset_keepalive_timer(sk
,
1666 tmo
- TCP_TIMEWAIT_LEN
);
1668 tcp_time_wait(sk
, TCP_FIN_WAIT2
, tmo
);
1673 if (sk
->sk_state
!= TCP_CLOSE
) {
1674 sk_stream_mem_reclaim(sk
);
1675 if (atomic_read(sk
->sk_prot
->orphan_count
) > sysctl_tcp_max_orphans
||
1676 (sk
->sk_wmem_queued
> SOCK_MIN_SNDBUF
&&
1677 atomic_read(&tcp_memory_allocated
) > sysctl_tcp_mem
[2])) {
1678 if (net_ratelimit())
1679 printk(KERN_INFO
"TCP: too many of orphaned "
1681 tcp_set_state(sk
, TCP_CLOSE
);
1682 tcp_send_active_reset(sk
, GFP_ATOMIC
);
1683 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY
);
1687 if (sk
->sk_state
== TCP_CLOSE
)
1688 inet_csk_destroy_sock(sk
);
1689 /* Otherwise, socket is reprieved until protocol close. */
1697 /* These states need RST on ABORT according to RFC793 */
1699 static inline int tcp_need_reset(int state
)
1701 return (1 << state
) &
1702 (TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
| TCPF_FIN_WAIT1
|
1703 TCPF_FIN_WAIT2
| TCPF_SYN_RECV
);
1706 int tcp_disconnect(struct sock
*sk
, int flags
)
1708 struct inet_sock
*inet
= inet_sk(sk
);
1709 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1710 struct tcp_sock
*tp
= tcp_sk(sk
);
1712 int old_state
= sk
->sk_state
;
1714 if (old_state
!= TCP_CLOSE
)
1715 tcp_set_state(sk
, TCP_CLOSE
);
1717 /* ABORT function of RFC793 */
1718 if (old_state
== TCP_LISTEN
) {
1719 inet_csk_listen_stop(sk
);
1720 } else if (tcp_need_reset(old_state
) ||
1721 (tp
->snd_nxt
!= tp
->write_seq
&&
1722 (1 << old_state
) & (TCPF_CLOSING
| TCPF_LAST_ACK
))) {
1723 /* The last check adjusts for discrepancy of Linux wrt. RFC
1726 tcp_send_active_reset(sk
, gfp_any());
1727 sk
->sk_err
= ECONNRESET
;
1728 } else if (old_state
== TCP_SYN_SENT
)
1729 sk
->sk_err
= ECONNRESET
;
1731 tcp_clear_xmit_timers(sk
);
1732 __skb_queue_purge(&sk
->sk_receive_queue
);
1733 sk_stream_writequeue_purge(sk
);
1734 __skb_queue_purge(&tp
->out_of_order_queue
);
1735 #ifdef CONFIG_NET_DMA
1736 __skb_queue_purge(&sk
->sk_async_wait_queue
);
1741 if (!(sk
->sk_userlocks
& SOCK_BINDADDR_LOCK
))
1742 inet_reset_saddr(sk
);
1744 sk
->sk_shutdown
= 0;
1745 sock_reset_flag(sk
, SOCK_DONE
);
1747 if ((tp
->write_seq
+= tp
->max_window
+ 2) == 0)
1749 icsk
->icsk_backoff
= 0;
1751 icsk
->icsk_probes_out
= 0;
1752 tp
->packets_out
= 0;
1753 tp
->snd_ssthresh
= 0x7fffffff;
1754 tp
->snd_cwnd_cnt
= 0;
1755 tp
->bytes_acked
= 0;
1756 tcp_set_ca_state(sk
, TCP_CA_Open
);
1757 tcp_clear_retrans(tp
);
1758 inet_csk_delack_init(sk
);
1759 sk
->sk_send_head
= NULL
;
1760 tp
->rx_opt
.saw_tstamp
= 0;
1761 tcp_sack_reset(&tp
->rx_opt
);
1764 BUG_TRAP(!inet
->num
|| icsk
->icsk_bind_hash
);
1766 sk
->sk_error_report(sk
);
1771 * Socket option code for TCP.
1773 static int do_tcp_setsockopt(struct sock
*sk
, int level
,
1774 int optname
, char __user
*optval
, int optlen
)
1776 struct tcp_sock
*tp
= tcp_sk(sk
);
1777 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1781 /* This is a string value all the others are int's */
1782 if (optname
== TCP_CONGESTION
) {
1783 char name
[TCP_CA_NAME_MAX
];
1788 val
= strncpy_from_user(name
, optval
,
1789 min(TCP_CA_NAME_MAX
-1, optlen
));
1795 err
= tcp_set_congestion_control(sk
, name
);
1800 if (optlen
< sizeof(int))
1803 if (get_user(val
, (int __user
*)optval
))
1810 /* Values greater than interface MTU won't take effect. However
1811 * at the point when this call is done we typically don't yet
1812 * know which interface is going to be used */
1813 if (val
< 8 || val
> MAX_TCP_WINDOW
) {
1817 tp
->rx_opt
.user_mss
= val
;
1822 /* TCP_NODELAY is weaker than TCP_CORK, so that
1823 * this option on corked socket is remembered, but
1824 * it is not activated until cork is cleared.
1826 * However, when TCP_NODELAY is set we make
1827 * an explicit push, which overrides even TCP_CORK
1828 * for currently queued segments.
1830 tp
->nonagle
|= TCP_NAGLE_OFF
|TCP_NAGLE_PUSH
;
1831 tcp_push_pending_frames(sk
, tp
);
1833 tp
->nonagle
&= ~TCP_NAGLE_OFF
;
1838 /* When set indicates to always queue non-full frames.
1839 * Later the user clears this option and we transmit
1840 * any pending partial frames in the queue. This is
1841 * meant to be used alongside sendfile() to get properly
1842 * filled frames when the user (for example) must write
1843 * out headers with a write() call first and then use
1844 * sendfile to send out the data parts.
1846 * TCP_CORK can be set together with TCP_NODELAY and it is
1847 * stronger than TCP_NODELAY.
1850 tp
->nonagle
|= TCP_NAGLE_CORK
;
1852 tp
->nonagle
&= ~TCP_NAGLE_CORK
;
1853 if (tp
->nonagle
&TCP_NAGLE_OFF
)
1854 tp
->nonagle
|= TCP_NAGLE_PUSH
;
1855 tcp_push_pending_frames(sk
, tp
);
1860 if (val
< 1 || val
> MAX_TCP_KEEPIDLE
)
1863 tp
->keepalive_time
= val
* HZ
;
1864 if (sock_flag(sk
, SOCK_KEEPOPEN
) &&
1865 !((1 << sk
->sk_state
) &
1866 (TCPF_CLOSE
| TCPF_LISTEN
))) {
1867 __u32 elapsed
= tcp_time_stamp
- tp
->rcv_tstamp
;
1868 if (tp
->keepalive_time
> elapsed
)
1869 elapsed
= tp
->keepalive_time
- elapsed
;
1872 inet_csk_reset_keepalive_timer(sk
, elapsed
);
1877 if (val
< 1 || val
> MAX_TCP_KEEPINTVL
)
1880 tp
->keepalive_intvl
= val
* HZ
;
1883 if (val
< 1 || val
> MAX_TCP_KEEPCNT
)
1886 tp
->keepalive_probes
= val
;
1889 if (val
< 1 || val
> MAX_TCP_SYNCNT
)
1892 icsk
->icsk_syn_retries
= val
;
1898 else if (val
> sysctl_tcp_fin_timeout
/ HZ
)
1901 tp
->linger2
= val
* HZ
;
1904 case TCP_DEFER_ACCEPT
:
1905 icsk
->icsk_accept_queue
.rskq_defer_accept
= 0;
1907 /* Translate value in seconds to number of
1909 while (icsk
->icsk_accept_queue
.rskq_defer_accept
< 32 &&
1910 val
> ((TCP_TIMEOUT_INIT
/ HZ
) <<
1911 icsk
->icsk_accept_queue
.rskq_defer_accept
))
1912 icsk
->icsk_accept_queue
.rskq_defer_accept
++;
1913 icsk
->icsk_accept_queue
.rskq_defer_accept
++;
1917 case TCP_WINDOW_CLAMP
:
1919 if (sk
->sk_state
!= TCP_CLOSE
) {
1923 tp
->window_clamp
= 0;
1925 tp
->window_clamp
= val
< SOCK_MIN_RCVBUF
/ 2 ?
1926 SOCK_MIN_RCVBUF
/ 2 : val
;
1931 icsk
->icsk_ack
.pingpong
= 1;
1933 icsk
->icsk_ack
.pingpong
= 0;
1934 if ((1 << sk
->sk_state
) &
1935 (TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
) &&
1936 inet_csk_ack_scheduled(sk
)) {
1937 icsk
->icsk_ack
.pending
|= ICSK_ACK_PUSHED
;
1938 tcp_cleanup_rbuf(sk
, 1);
1940 icsk
->icsk_ack
.pingpong
= 1;
1953 int tcp_setsockopt(struct sock
*sk
, int level
, int optname
, char __user
*optval
,
1956 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1958 if (level
!= SOL_TCP
)
1959 return icsk
->icsk_af_ops
->setsockopt(sk
, level
, optname
,
1961 return do_tcp_setsockopt(sk
, level
, optname
, optval
, optlen
);
1964 #ifdef CONFIG_COMPAT
1965 int compat_tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
1966 char __user
*optval
, int optlen
)
1968 if (level
!= SOL_TCP
)
1969 return inet_csk_compat_setsockopt(sk
, level
, optname
,
1971 return do_tcp_setsockopt(sk
, level
, optname
, optval
, optlen
);
1974 EXPORT_SYMBOL(compat_tcp_setsockopt
);
1977 /* Return information about state of tcp endpoint in API format. */
1978 void tcp_get_info(struct sock
*sk
, struct tcp_info
*info
)
1980 struct tcp_sock
*tp
= tcp_sk(sk
);
1981 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1982 u32 now
= tcp_time_stamp
;
1984 memset(info
, 0, sizeof(*info
));
1986 info
->tcpi_state
= sk
->sk_state
;
1987 info
->tcpi_ca_state
= icsk
->icsk_ca_state
;
1988 info
->tcpi_retransmits
= icsk
->icsk_retransmits
;
1989 info
->tcpi_probes
= icsk
->icsk_probes_out
;
1990 info
->tcpi_backoff
= icsk
->icsk_backoff
;
1992 if (tp
->rx_opt
.tstamp_ok
)
1993 info
->tcpi_options
|= TCPI_OPT_TIMESTAMPS
;
1994 if (tp
->rx_opt
.sack_ok
)
1995 info
->tcpi_options
|= TCPI_OPT_SACK
;
1996 if (tp
->rx_opt
.wscale_ok
) {
1997 info
->tcpi_options
|= TCPI_OPT_WSCALE
;
1998 info
->tcpi_snd_wscale
= tp
->rx_opt
.snd_wscale
;
1999 info
->tcpi_rcv_wscale
= tp
->rx_opt
.rcv_wscale
;
2002 if (tp
->ecn_flags
&TCP_ECN_OK
)
2003 info
->tcpi_options
|= TCPI_OPT_ECN
;
2005 info
->tcpi_rto
= jiffies_to_usecs(icsk
->icsk_rto
);
2006 info
->tcpi_ato
= jiffies_to_usecs(icsk
->icsk_ack
.ato
);
2007 info
->tcpi_snd_mss
= tp
->mss_cache
;
2008 info
->tcpi_rcv_mss
= icsk
->icsk_ack
.rcv_mss
;
2010 info
->tcpi_unacked
= tp
->packets_out
;
2011 info
->tcpi_sacked
= tp
->sacked_out
;
2012 info
->tcpi_lost
= tp
->lost_out
;
2013 info
->tcpi_retrans
= tp
->retrans_out
;
2014 info
->tcpi_fackets
= tp
->fackets_out
;
2016 info
->tcpi_last_data_sent
= jiffies_to_msecs(now
- tp
->lsndtime
);
2017 info
->tcpi_last_data_recv
= jiffies_to_msecs(now
- icsk
->icsk_ack
.lrcvtime
);
2018 info
->tcpi_last_ack_recv
= jiffies_to_msecs(now
- tp
->rcv_tstamp
);
2020 info
->tcpi_pmtu
= icsk
->icsk_pmtu_cookie
;
2021 info
->tcpi_rcv_ssthresh
= tp
->rcv_ssthresh
;
2022 info
->tcpi_rtt
= jiffies_to_usecs(tp
->srtt
)>>3;
2023 info
->tcpi_rttvar
= jiffies_to_usecs(tp
->mdev
)>>2;
2024 info
->tcpi_snd_ssthresh
= tp
->snd_ssthresh
;
2025 info
->tcpi_snd_cwnd
= tp
->snd_cwnd
;
2026 info
->tcpi_advmss
= tp
->advmss
;
2027 info
->tcpi_reordering
= tp
->reordering
;
2029 info
->tcpi_rcv_rtt
= jiffies_to_usecs(tp
->rcv_rtt_est
.rtt
)>>3;
2030 info
->tcpi_rcv_space
= tp
->rcvq_space
.space
;
2032 info
->tcpi_total_retrans
= tp
->total_retrans
;
2035 EXPORT_SYMBOL_GPL(tcp_get_info
);
2037 static int do_tcp_getsockopt(struct sock
*sk
, int level
,
2038 int optname
, char __user
*optval
, int __user
*optlen
)
2040 struct inet_connection_sock
*icsk
= inet_csk(sk
);
2041 struct tcp_sock
*tp
= tcp_sk(sk
);
2044 if (get_user(len
, optlen
))
2047 len
= min_t(unsigned int, len
, sizeof(int));
2054 val
= tp
->mss_cache
;
2055 if (!val
&& ((1 << sk
->sk_state
) & (TCPF_CLOSE
| TCPF_LISTEN
)))
2056 val
= tp
->rx_opt
.user_mss
;
2059 val
= !!(tp
->nonagle
&TCP_NAGLE_OFF
);
2062 val
= !!(tp
->nonagle
&TCP_NAGLE_CORK
);
2065 val
= (tp
->keepalive_time
? : sysctl_tcp_keepalive_time
) / HZ
;
2068 val
= (tp
->keepalive_intvl
? : sysctl_tcp_keepalive_intvl
) / HZ
;
2071 val
= tp
->keepalive_probes
? : sysctl_tcp_keepalive_probes
;
2074 val
= icsk
->icsk_syn_retries
? : sysctl_tcp_syn_retries
;
2079 val
= (val
? : sysctl_tcp_fin_timeout
) / HZ
;
2081 case TCP_DEFER_ACCEPT
:
2082 val
= !icsk
->icsk_accept_queue
.rskq_defer_accept
? 0 :
2083 ((TCP_TIMEOUT_INIT
/ HZ
) << (icsk
->icsk_accept_queue
.rskq_defer_accept
- 1));
2085 case TCP_WINDOW_CLAMP
:
2086 val
= tp
->window_clamp
;
2089 struct tcp_info info
;
2091 if (get_user(len
, optlen
))
2094 tcp_get_info(sk
, &info
);
2096 len
= min_t(unsigned int, len
, sizeof(info
));
2097 if (put_user(len
, optlen
))
2099 if (copy_to_user(optval
, &info
, len
))
2104 val
= !icsk
->icsk_ack
.pingpong
;
2107 case TCP_CONGESTION
:
2108 if (get_user(len
, optlen
))
2110 len
= min_t(unsigned int, len
, TCP_CA_NAME_MAX
);
2111 if (put_user(len
, optlen
))
2113 if (copy_to_user(optval
, icsk
->icsk_ca_ops
->name
, len
))
2117 return -ENOPROTOOPT
;
2120 if (put_user(len
, optlen
))
2122 if (copy_to_user(optval
, &val
, len
))
2127 int tcp_getsockopt(struct sock
*sk
, int level
, int optname
, char __user
*optval
,
2130 struct inet_connection_sock
*icsk
= inet_csk(sk
);
2132 if (level
!= SOL_TCP
)
2133 return icsk
->icsk_af_ops
->getsockopt(sk
, level
, optname
,
2135 return do_tcp_getsockopt(sk
, level
, optname
, optval
, optlen
);
2138 #ifdef CONFIG_COMPAT
2139 int compat_tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
2140 char __user
*optval
, int __user
*optlen
)
2142 if (level
!= SOL_TCP
)
2143 return inet_csk_compat_getsockopt(sk
, level
, optname
,
2145 return do_tcp_getsockopt(sk
, level
, optname
, optval
, optlen
);
2148 EXPORT_SYMBOL(compat_tcp_getsockopt
);
2151 struct sk_buff
*tcp_tso_segment(struct sk_buff
*skb
, int features
)
2153 struct sk_buff
*segs
= ERR_PTR(-EINVAL
);
2158 unsigned int oldlen
;
2161 if (!pskb_may_pull(skb
, sizeof(*th
)))
2165 thlen
= th
->doff
* 4;
2166 if (thlen
< sizeof(*th
))
2169 if (!pskb_may_pull(skb
, thlen
))
2172 oldlen
= (u16
)~skb
->len
;
2173 __skb_pull(skb
, thlen
);
2175 if (skb_gso_ok(skb
, features
| NETIF_F_GSO_ROBUST
)) {
2176 /* Packet is from an untrusted source, reset gso_segs. */
2177 int type
= skb_shinfo(skb
)->gso_type
;
2186 !(type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
))))
2189 mss
= skb_shinfo(skb
)->gso_size
;
2190 skb_shinfo(skb
)->gso_segs
= (skb
->len
+ mss
- 1) / mss
;
2196 segs
= skb_segment(skb
, features
);
2200 len
= skb_shinfo(skb
)->gso_size
;
2201 delta
= htonl(oldlen
+ (thlen
+ len
));
2205 seq
= ntohl(th
->seq
);
2208 th
->fin
= th
->psh
= 0;
2210 th
->check
= ~csum_fold(th
->check
+ delta
);
2211 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
)
2212 th
->check
= csum_fold(csum_partial(skb
->h
.raw
, thlen
,
2219 th
->seq
= htonl(seq
);
2221 } while (skb
->next
);
2223 delta
= htonl(oldlen
+ (skb
->tail
- skb
->h
.raw
) + skb
->data_len
);
2224 th
->check
= ~csum_fold(th
->check
+ delta
);
2225 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
)
2226 th
->check
= csum_fold(csum_partial(skb
->h
.raw
, thlen
,
2232 EXPORT_SYMBOL(tcp_tso_segment
);
2234 extern void __skb_cb_too_small_for_tcp(int, int);
2235 extern struct tcp_congestion_ops tcp_reno
;
2237 static __initdata
unsigned long thash_entries
;
2238 static int __init
set_thash_entries(char *str
)
2242 thash_entries
= simple_strtoul(str
, &str
, 0);
2245 __setup("thash_entries=", set_thash_entries
);
2247 void __init
tcp_init(void)
2249 struct sk_buff
*skb
= NULL
;
2250 unsigned long limit
;
2251 int order
, i
, max_share
;
2253 if (sizeof(struct tcp_skb_cb
) > sizeof(skb
->cb
))
2254 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb
),
2257 tcp_hashinfo
.bind_bucket_cachep
=
2258 kmem_cache_create("tcp_bind_bucket",
2259 sizeof(struct inet_bind_bucket
), 0,
2260 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
, NULL
);
2262 /* Size and allocate the main established and bind bucket
2265 * The methodology is similar to that of the buffer cache.
2267 tcp_hashinfo
.ehash
=
2268 alloc_large_system_hash("TCP established",
2269 sizeof(struct inet_ehash_bucket
),
2271 (num_physpages
>= 128 * 1024) ?
2274 &tcp_hashinfo
.ehash_size
,
2277 tcp_hashinfo
.ehash_size
= (1 << tcp_hashinfo
.ehash_size
) >> 1;
2278 for (i
= 0; i
< (tcp_hashinfo
.ehash_size
<< 1); i
++) {
2279 rwlock_init(&tcp_hashinfo
.ehash
[i
].lock
);
2280 INIT_HLIST_HEAD(&tcp_hashinfo
.ehash
[i
].chain
);
2283 tcp_hashinfo
.bhash
=
2284 alloc_large_system_hash("TCP bind",
2285 sizeof(struct inet_bind_hashbucket
),
2286 tcp_hashinfo
.ehash_size
,
2287 (num_physpages
>= 128 * 1024) ?
2290 &tcp_hashinfo
.bhash_size
,
2293 tcp_hashinfo
.bhash_size
= 1 << tcp_hashinfo
.bhash_size
;
2294 for (i
= 0; i
< tcp_hashinfo
.bhash_size
; i
++) {
2295 spin_lock_init(&tcp_hashinfo
.bhash
[i
].lock
);
2296 INIT_HLIST_HEAD(&tcp_hashinfo
.bhash
[i
].chain
);
2299 /* Try to be a bit smarter and adjust defaults depending
2300 * on available memory.
2302 for (order
= 0; ((1 << order
) << PAGE_SHIFT
) <
2303 (tcp_hashinfo
.bhash_size
* sizeof(struct inet_bind_hashbucket
));
2307 sysctl_local_port_range
[0] = 32768;
2308 sysctl_local_port_range
[1] = 61000;
2309 tcp_death_row
.sysctl_max_tw_buckets
= 180000;
2310 sysctl_tcp_max_orphans
= 4096 << (order
- 4);
2311 sysctl_max_syn_backlog
= 1024;
2312 } else if (order
< 3) {
2313 sysctl_local_port_range
[0] = 1024 * (3 - order
);
2314 tcp_death_row
.sysctl_max_tw_buckets
>>= (3 - order
);
2315 sysctl_tcp_max_orphans
>>= (3 - order
);
2316 sysctl_max_syn_backlog
= 128;
2319 /* Allow no more than 3/4 kernel memory (usually less) allocated to TCP */
2320 sysctl_tcp_mem
[0] = (1536 / sizeof (struct inet_bind_hashbucket
)) << order
;
2321 sysctl_tcp_mem
[1] = sysctl_tcp_mem
[0] * 4 / 3;
2322 sysctl_tcp_mem
[2] = sysctl_tcp_mem
[0] * 2;
2324 limit
= ((unsigned long)sysctl_tcp_mem
[1]) << (PAGE_SHIFT
- 7);
2325 max_share
= min(4UL*1024*1024, limit
);
2327 sysctl_tcp_wmem
[0] = SK_STREAM_MEM_QUANTUM
;
2328 sysctl_tcp_wmem
[1] = 16*1024;
2329 sysctl_tcp_wmem
[2] = max(64*1024, max_share
);
2331 sysctl_tcp_rmem
[0] = SK_STREAM_MEM_QUANTUM
;
2332 sysctl_tcp_rmem
[1] = 87380;
2333 sysctl_tcp_rmem
[2] = max(87380, max_share
);
2335 printk(KERN_INFO
"TCP: Hash tables configured "
2336 "(established %d bind %d)\n",
2337 tcp_hashinfo
.ehash_size
<< 1, tcp_hashinfo
.bhash_size
);
2339 tcp_register_congestion_control(&tcp_reno
);
2342 EXPORT_SYMBOL(tcp_close
);
2343 EXPORT_SYMBOL(tcp_disconnect
);
2344 EXPORT_SYMBOL(tcp_getsockopt
);
2345 EXPORT_SYMBOL(tcp_ioctl
);
2346 EXPORT_SYMBOL(tcp_poll
);
2347 EXPORT_SYMBOL(tcp_read_sock
);
2348 EXPORT_SYMBOL(tcp_recvmsg
);
2349 EXPORT_SYMBOL(tcp_sendmsg
);
2350 EXPORT_SYMBOL(tcp_sendpage
);
2351 EXPORT_SYMBOL(tcp_setsockopt
);
2352 EXPORT_SYMBOL(tcp_shutdown
);
2353 EXPORT_SYMBOL(tcp_statistics
);