tcp: Remove unrequired operations in tcp_push()
[linux-2.6.git] / net / ipv4 / tcp.c
1 /*
2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
3  *              operating system.  INET is implemented using the  BSD Socket
4  *              interface as the means of communication with the user level.
5  *
6  *              Implementation of the Transmission Control Protocol(TCP).
7  *
8  * Authors:     Ross Biro
9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
11  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
12  *              Florian La Roche, <flla@stud.uni-sb.de>
13  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
15  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
16  *              Matthew Dillon, <dillon@apollo.west.oic.com>
17  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18  *              Jorge Cwik, <jorge@laser.satlink.net>
19  *
20  * Fixes:
21  *              Alan Cox        :       Numerous verify_area() calls
22  *              Alan Cox        :       Set the ACK bit on a reset
23  *              Alan Cox        :       Stopped it crashing if it closed while
24  *                                      sk->inuse=1 and was trying to connect
25  *                                      (tcp_err()).
26  *              Alan Cox        :       All icmp error handling was broken
27  *                                      pointers passed where wrong and the
28  *                                      socket was looked up backwards. Nobody
29  *                                      tested any icmp error code obviously.
30  *              Alan Cox        :       tcp_err() now handled properly. It
31  *                                      wakes people on errors. poll
32  *                                      behaves and the icmp error race
33  *                                      has gone by moving it into sock.c
34  *              Alan Cox        :       tcp_send_reset() fixed to work for
35  *                                      everything not just packets for
36  *                                      unknown sockets.
37  *              Alan Cox        :       tcp option processing.
38  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
39  *                                      syn rule wrong]
40  *              Herp Rosmanith  :       More reset fixes
41  *              Alan Cox        :       No longer acks invalid rst frames.
42  *                                      Acking any kind of RST is right out.
43  *              Alan Cox        :       Sets an ignore me flag on an rst
44  *                                      receive otherwise odd bits of prattle
45  *                                      escape still
46  *              Alan Cox        :       Fixed another acking RST frame bug.
47  *                                      Should stop LAN workplace lockups.
48  *              Alan Cox        :       Some tidyups using the new skb list
49  *                                      facilities
50  *              Alan Cox        :       sk->keepopen now seems to work
51  *              Alan Cox        :       Pulls options out correctly on accepts
52  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
53  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
54  *                                      bit to skb ops.
55  *              Alan Cox        :       Tidied tcp_data to avoid a potential
56  *                                      nasty.
57  *              Alan Cox        :       Added some better commenting, as the
58  *                                      tcp is hard to follow
59  *              Alan Cox        :       Removed incorrect check for 20 * psh
60  *      Michael O'Reilly        :       ack < copied bug fix.
61  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
62  *              Alan Cox        :       FIN with no memory -> CRASH
63  *              Alan Cox        :       Added socket option proto entries.
64  *                                      Also added awareness of them to accept.
65  *              Alan Cox        :       Added TCP options (SOL_TCP)
66  *              Alan Cox        :       Switched wakeup calls to callbacks,
67  *                                      so the kernel can layer network
68  *                                      sockets.
69  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
70  *              Alan Cox        :       Handle FIN (more) properly (we hope).
71  *              Alan Cox        :       RST frames sent on unsynchronised
72  *                                      state ack error.
73  *              Alan Cox        :       Put in missing check for SYN bit.
74  *              Alan Cox        :       Added tcp_select_window() aka NET2E
75  *                                      window non shrink trick.
76  *              Alan Cox        :       Added a couple of small NET2E timer
77  *                                      fixes
78  *              Charles Hedrick :       TCP fixes
79  *              Toomas Tamm     :       TCP window fixes
80  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
81  *              Charles Hedrick :       Rewrote most of it to actually work
82  *              Linus           :       Rewrote tcp_read() and URG handling
83  *                                      completely
84  *              Gerhard Koerting:       Fixed some missing timer handling
85  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
86  *              Gerhard Koerting:       PC/TCP workarounds
87  *              Adam Caldwell   :       Assorted timer/timing errors
88  *              Matthew Dillon  :       Fixed another RST bug
89  *              Alan Cox        :       Move to kernel side addressing changes.
90  *              Alan Cox        :       Beginning work on TCP fastpathing
91  *                                      (not yet usable)
92  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
93  *              Alan Cox        :       TCP fast path debugging
94  *              Alan Cox        :       Window clamping
95  *              Michael Riepe   :       Bug in tcp_check()
96  *              Matt Dillon     :       More TCP improvements and RST bug fixes
97  *              Matt Dillon     :       Yet more small nasties remove from the
98  *                                      TCP code (Be very nice to this man if
99  *                                      tcp finally works 100%) 8)
100  *              Alan Cox        :       BSD accept semantics.
101  *              Alan Cox        :       Reset on closedown bug.
102  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
103  *              Michael Pall    :       Handle poll() after URG properly in
104  *                                      all cases.
105  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
106  *                                      (multi URG PUSH broke rlogin).
107  *              Michael Pall    :       Fix the multi URG PUSH problem in
108  *                                      tcp_readable(), poll() after URG
109  *                                      works now.
110  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
111  *                                      BSD api.
112  *              Alan Cox        :       Changed the semantics of sk->socket to
113  *                                      fix a race and a signal problem with
114  *                                      accept() and async I/O.
115  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
116  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
117  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
118  *                                      clients/servers which listen in on
119  *                                      fixed ports.
120  *              Alan Cox        :       Cleaned the above up and shrank it to
121  *                                      a sensible code size.
122  *              Alan Cox        :       Self connect lockup fix.
123  *              Alan Cox        :       No connect to multicast.
124  *              Ross Biro       :       Close unaccepted children on master
125  *                                      socket close.
126  *              Alan Cox        :       Reset tracing code.
127  *              Alan Cox        :       Spurious resets on shutdown.
128  *              Alan Cox        :       Giant 15 minute/60 second timer error
129  *              Alan Cox        :       Small whoops in polling before an
130  *                                      accept.
131  *              Alan Cox        :       Kept the state trace facility since
132  *                                      it's handy for debugging.
133  *              Alan Cox        :       More reset handler fixes.
134  *              Alan Cox        :       Started rewriting the code based on
135  *                                      the RFC's for other useful protocol
136  *                                      references see: Comer, KA9Q NOS, and
137  *                                      for a reference on the difference
138  *                                      between specifications and how BSD
139  *                                      works see the 4.4lite source.
140  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
141  *                                      close.
142  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
143  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
144  *              Alan Cox        :       Reimplemented timers as per the RFC
145  *                                      and using multiple timers for sanity.
146  *              Alan Cox        :       Small bug fixes, and a lot of new
147  *                                      comments.
148  *              Alan Cox        :       Fixed dual reader crash by locking
149  *                                      the buffers (much like datagram.c)
150  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
151  *                                      now gets fed up of retrying without
152  *                                      (even a no space) answer.
153  *              Alan Cox        :       Extracted closing code better
154  *              Alan Cox        :       Fixed the closing state machine to
155  *                                      resemble the RFC.
156  *              Alan Cox        :       More 'per spec' fixes.
157  *              Jorge Cwik      :       Even faster checksumming.
158  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
159  *                                      only frames. At least one pc tcp stack
160  *                                      generates them.
161  *              Alan Cox        :       Cache last socket.
162  *              Alan Cox        :       Per route irtt.
163  *              Matt Day        :       poll()->select() match BSD precisely on error
164  *              Alan Cox        :       New buffers
165  *              Marc Tamsky     :       Various sk->prot->retransmits and
166  *                                      sk->retransmits misupdating fixed.
167  *                                      Fixed tcp_write_timeout: stuck close,
168  *                                      and TCP syn retries gets used now.
169  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
170  *                                      ack if state is TCP_CLOSED.
171  *              Alan Cox        :       Look up device on a retransmit - routes may
172  *                                      change. Doesn't yet cope with MSS shrink right
173  *                                      but it's a start!
174  *              Marc Tamsky     :       Closing in closing fixes.
175  *              Mike Shaver     :       RFC1122 verifications.
176  *              Alan Cox        :       rcv_saddr errors.
177  *              Alan Cox        :       Block double connect().
178  *              Alan Cox        :       Small hooks for enSKIP.
179  *              Alexey Kuznetsov:       Path MTU discovery.
180  *              Alan Cox        :       Support soft errors.
181  *              Alan Cox        :       Fix MTU discovery pathological case
182  *                                      when the remote claims no mtu!
183  *              Marc Tamsky     :       TCP_CLOSE fix.
184  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
185  *                                      window but wrong (fixes NT lpd problems)
186  *              Pedro Roque     :       Better TCP window handling, delayed ack.
187  *              Joerg Reuter    :       No modification of locked buffers in
188  *                                      tcp_do_retransmit()
189  *              Eric Schenk     :       Changed receiver side silly window
190  *                                      avoidance algorithm to BSD style
191  *                                      algorithm. This doubles throughput
192  *                                      against machines running Solaris,
193  *                                      and seems to result in general
194  *                                      improvement.
195  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
196  *      Willy Konynenberg       :       Transparent proxying support.
197  *      Mike McLagan            :       Routing by source
198  *              Keith Owens     :       Do proper merging with partial SKB's in
199  *                                      tcp_do_sendmsg to avoid burstiness.
200  *              Eric Schenk     :       Fix fast close down bug with
201  *                                      shutdown() followed by close().
202  *              Andi Kleen      :       Make poll agree with SIGIO
203  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
204  *                                      lingertime == 0 (RFC 793 ABORT Call)
205  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
206  *                                      csum_and_copy_from_user() if possible.
207  *
208  *              This program is free software; you can redistribute it and/or
209  *              modify it under the terms of the GNU General Public License
210  *              as published by the Free Software Foundation; either version
211  *              2 of the License, or(at your option) any later version.
212  *
213  * Description of States:
214  *
215  *      TCP_SYN_SENT            sent a connection request, waiting for ack
216  *
217  *      TCP_SYN_RECV            received a connection request, sent ack,
218  *                              waiting for final ack in three-way handshake.
219  *
220  *      TCP_ESTABLISHED         connection established
221  *
222  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
223  *                              transmission of remaining buffered data
224  *
225  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
226  *                              to shutdown
227  *
228  *      TCP_CLOSING             both sides have shutdown but we still have
229  *                              data we have to finish sending
230  *
231  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
232  *                              closed, can only be entered from FIN_WAIT2
233  *                              or CLOSING.  Required because the other end
234  *                              may not have gotten our last ACK causing it
235  *                              to retransmit the data packet (which we ignore)
236  *
237  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
238  *                              us to finish writing our data and to shutdown
239  *                              (we have to close() to move on to LAST_ACK)
240  *
241  *      TCP_LAST_ACK            out side has shutdown after remote has
242  *                              shutdown.  There may still be data in our
243  *                              buffer that we have to finish sending
244  *
245  *      TCP_CLOSE               socket is finished
246  */
247
248 #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>
268
269 #include <net/icmp.h>
270 #include <net/tcp.h>
271 #include <net/xfrm.h>
272 #include <net/ip.h>
273 #include <net/netdma.h>
274 #include <net/sock.h>
275
276 #include <asm/uaccess.h>
277 #include <asm/ioctls.h>
278
279 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
280
281 struct percpu_counter tcp_orphan_count;
282 EXPORT_SYMBOL_GPL(tcp_orphan_count);
283
284 int sysctl_tcp_mem[3] __read_mostly;
285 int sysctl_tcp_wmem[3] __read_mostly;
286 int sysctl_tcp_rmem[3] __read_mostly;
287
288 EXPORT_SYMBOL(sysctl_tcp_mem);
289 EXPORT_SYMBOL(sysctl_tcp_rmem);
290 EXPORT_SYMBOL(sysctl_tcp_wmem);
291
292 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
293 EXPORT_SYMBOL(tcp_memory_allocated);
294
295 /*
296  * Current number of TCP sockets.
297  */
298 struct percpu_counter tcp_sockets_allocated;
299 EXPORT_SYMBOL(tcp_sockets_allocated);
300
301 /*
302  * TCP splice context
303  */
304 struct tcp_splice_state {
305         struct pipe_inode_info *pipe;
306         size_t len;
307         unsigned int flags;
308 };
309
310 /*
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.
315  */
316 int tcp_memory_pressure __read_mostly;
317
318 EXPORT_SYMBOL(tcp_memory_pressure);
319
320 void tcp_enter_memory_pressure(struct sock *sk)
321 {
322         if (!tcp_memory_pressure) {
323                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324                 tcp_memory_pressure = 1;
325         }
326 }
327
328 EXPORT_SYMBOL(tcp_enter_memory_pressure);
329
330 /* Convert seconds to retransmits based on initial and max timeout */
331 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
332 {
333         u8 res = 0;
334
335         if (seconds > 0) {
336                 int period = timeout;
337
338                 res = 1;
339                 while (seconds > period && res < 255) {
340                         res++;
341                         timeout <<= 1;
342                         if (timeout > rto_max)
343                                 timeout = rto_max;
344                         period += timeout;
345                 }
346         }
347         return res;
348 }
349
350 /* Convert retransmits to seconds based on initial and max timeout */
351 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
352 {
353         int period = 0;
354
355         if (retrans > 0) {
356                 period = timeout;
357                 while (--retrans) {
358                         timeout <<= 1;
359                         if (timeout > rto_max)
360                                 timeout = rto_max;
361                         period += timeout;
362                 }
363         }
364         return period;
365 }
366
367 /*
368  *      Wait for a TCP event.
369  *
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.
373  */
374 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
375 {
376         unsigned int mask;
377         struct sock *sk = sock->sk;
378         struct tcp_sock *tp = tcp_sk(sk);
379
380         sock_poll_wait(file, sk->sk_sleep, wait);
381         if (sk->sk_state == TCP_LISTEN)
382                 return inet_csk_listen_poll(sk);
383
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.
387          */
388
389         mask = 0;
390         if (sk->sk_err)
391                 mask = POLLERR;
392
393         /*
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.
397          *
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!
403          *
404          * Check-me.
405          *
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
416          *
417          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
418          * blocking on fresh not-connected or disconnected socket. --ANK
419          */
420         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
421                 mask |= POLLHUP;
422         if (sk->sk_shutdown & RCV_SHUTDOWN)
423                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
424
425         /* Connected? */
426         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
427                 int target = sock_rcvlowat(sk, 0, INT_MAX);
428
429                 if (tp->urg_seq == tp->copied_seq &&
430                     !sock_flag(sk, SOCK_URGINLINE) &&
431                     tp->urg_data)
432                         target--;
433
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;
439
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);
447
448                                 /* Race breaker. If space is freed after
449                                  * wspace test but before the flags are set,
450                                  * IO signal will be lost.
451                                  */
452                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
453                                         mask |= POLLOUT | POLLWRNORM;
454                         }
455                 }
456
457                 if (tp->urg_data & TCP_URG_VALID)
458                         mask |= POLLPRI;
459         }
460         return mask;
461 }
462
463 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
464 {
465         struct tcp_sock *tp = tcp_sk(sk);
466         int answ;
467
468         switch (cmd) {
469         case SIOCINQ:
470                 if (sk->sk_state == TCP_LISTEN)
471                         return -EINVAL;
472
473                 lock_sock(sk);
474                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
475                         answ = 0;
476                 else if (sock_flag(sk, SOCK_URGINLINE) ||
477                          !tp->urg_data ||
478                          before(tp->urg_seq, tp->copied_seq) ||
479                          !before(tp->urg_seq, tp->rcv_nxt)) {
480                         struct sk_buff *skb;
481
482                         answ = tp->rcv_nxt - tp->copied_seq;
483
484                         /* Subtract 1, if FIN is in queue. */
485                         skb = skb_peek_tail(&sk->sk_receive_queue);
486                         if (answ && skb)
487                                 answ -= tcp_hdr(skb)->fin;
488                 } else
489                         answ = tp->urg_seq - tp->copied_seq;
490                 release_sock(sk);
491                 break;
492         case SIOCATMARK:
493                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
494                 break;
495         case SIOCOUTQ:
496                 if (sk->sk_state == TCP_LISTEN)
497                         return -EINVAL;
498
499                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
500                         answ = 0;
501                 else
502                         answ = tp->write_seq - tp->snd_una;
503                 break;
504         default:
505                 return -ENOIOCTLCMD;
506         }
507
508         return put_user(answ, (int __user *)arg);
509 }
510
511 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
512 {
513         TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
514         tp->pushed_seq = tp->write_seq;
515 }
516
517 static inline int forced_push(struct tcp_sock *tp)
518 {
519         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
520 }
521
522 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
523 {
524         struct tcp_sock *tp = tcp_sk(sk);
525         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
526
527         skb->csum    = 0;
528         tcb->seq     = tcb->end_seq = tp->write_seq;
529         tcb->flags   = TCPCB_FLAG_ACK;
530         tcb->sacked  = 0;
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;
537 }
538
539 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
540 {
541         if (flags & MSG_OOB)
542                 tp->snd_up = tp->write_seq;
543 }
544
545 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
546                             int nonagle)
547 {
548         if (tcp_send_head(sk)) {
549                 struct tcp_sock *tp = tcp_sk(sk);
550
551                 if (!(flags & MSG_MORE) || forced_push(tp))
552                         tcp_mark_push(tp, tcp_write_queue_tail(sk));
553
554                 tcp_mark_urg(tp, flags);
555                 __tcp_push_pending_frames(sk, mss_now,
556                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
557         }
558 }
559
560 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
561                                 unsigned int offset, size_t len)
562 {
563         struct tcp_splice_state *tss = rd_desc->arg.data;
564         int ret;
565
566         ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
567                               tss->flags);
568         if (ret > 0)
569                 rd_desc->count -= ret;
570         return ret;
571 }
572
573 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
574 {
575         /* Store TCP splice context information in read_descriptor_t. */
576         read_descriptor_t rd_desc = {
577                 .arg.data = tss,
578                 .count    = tss->len,
579         };
580
581         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
582 }
583
584 /**
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
591  *
592  * Description:
593  *    Will read pages from given socket and fill them into a pipe.
594  *
595  **/
596 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
597                         struct pipe_inode_info *pipe, size_t len,
598                         unsigned int flags)
599 {
600         struct sock *sk = sock->sk;
601         struct tcp_splice_state tss = {
602                 .pipe = pipe,
603                 .len = len,
604                 .flags = flags,
605         };
606         long timeo;
607         ssize_t spliced;
608         int ret;
609
610         /*
611          * We can't seek on a socket input
612          */
613         if (unlikely(*ppos))
614                 return -ESPIPE;
615
616         ret = spliced = 0;
617
618         lock_sock(sk);
619
620         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
621         while (tss.len) {
622                 ret = __tcp_splice_read(sk, &tss);
623                 if (ret < 0)
624                         break;
625                 else if (!ret) {
626                         if (spliced)
627                                 break;
628                         if (sock_flag(sk, SOCK_DONE))
629                                 break;
630                         if (sk->sk_err) {
631                                 ret = sock_error(sk);
632                                 break;
633                         }
634                         if (sk->sk_shutdown & RCV_SHUTDOWN)
635                                 break;
636                         if (sk->sk_state == TCP_CLOSE) {
637                                 /*
638                                  * This occurs when user tries to read
639                                  * from never connected socket.
640                                  */
641                                 if (!sock_flag(sk, SOCK_DONE))
642                                         ret = -ENOTCONN;
643                                 break;
644                         }
645                         if (!timeo) {
646                                 ret = -EAGAIN;
647                                 break;
648                         }
649                         sk_wait_data(sk, &timeo);
650                         if (signal_pending(current)) {
651                                 ret = sock_intr_errno(timeo);
652                                 break;
653                         }
654                         continue;
655                 }
656                 tss.len -= ret;
657                 spliced += ret;
658
659                 if (!timeo)
660                         break;
661                 release_sock(sk);
662                 lock_sock(sk);
663
664                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
665                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
666                     signal_pending(current))
667                         break;
668         }
669
670         release_sock(sk);
671
672         if (spliced)
673                 return spliced;
674
675         return ret;
676 }
677
678 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
679 {
680         struct sk_buff *skb;
681
682         /* The TCP header must be at least 32-bit aligned.  */
683         size = ALIGN(size, 4);
684
685         skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
686         if (skb) {
687                 if (sk_wmem_schedule(sk, skb->truesize)) {
688                         /*
689                          * Make sure that we have exactly size bytes
690                          * available to the caller, no more, no less.
691                          */
692                         skb_reserve(skb, skb_tailroom(skb) - size);
693                         return skb;
694                 }
695                 __kfree_skb(skb);
696         } else {
697                 sk->sk_prot->enter_memory_pressure(sk);
698                 sk_stream_moderate_sndbuf(sk);
699         }
700         return NULL;
701 }
702
703 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
704                                        int large_allowed)
705 {
706         struct tcp_sock *tp = tcp_sk(sk);
707         u32 xmit_size_goal, old_size_goal;
708
709         xmit_size_goal = mss_now;
710
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 -
715                                   tp->tcp_header_len);
716
717                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
718
719                 /* We try hard to avoid divides here */
720                 old_size_goal = tp->xmit_size_goal_segs * mss_now;
721
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;
725                 } else {
726                         tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
727                         xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
728                 }
729         }
730
731         return max(xmit_size_goal, mss_now);
732 }
733
734 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
735 {
736         int mss_now;
737
738         mss_now = tcp_current_mss(sk);
739         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
740
741         return mss_now;
742 }
743
744 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
745                          size_t psize, int flags)
746 {
747         struct tcp_sock *tp = tcp_sk(sk);
748         int mss_now, size_goal;
749         int err;
750         ssize_t copied;
751         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
752
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)
756                         goto out_err;
757
758         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
759
760         mss_now = tcp_send_mss(sk, &size_goal, flags);
761         copied = 0;
762
763         err = -EPIPE;
764         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
765                 goto out_err;
766
767         while (psize > 0) {
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);
773
774                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
775 new_segment:
776                         if (!sk_stream_memory_free(sk))
777                                 goto wait_for_sndbuf;
778
779                         skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
780                         if (!skb)
781                                 goto wait_for_memory;
782
783                         skb_entail(sk, skb);
784                         copy = size_goal;
785                 }
786
787                 if (copy > size)
788                         copy = size;
789
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);
794                         goto new_segment;
795                 }
796                 if (!sk_wmem_schedule(sk, copy))
797                         goto wait_for_memory;
798
799                 if (can_coalesce) {
800                         skb_shinfo(skb)->frags[i - 1].size += copy;
801                 } else {
802                         get_page(page);
803                         skb_fill_page_desc(skb, i, page, offset, copy);
804                 }
805
806                 skb->len += 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;
815
816                 if (!copied)
817                         TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
818
819                 copied += copy;
820                 poffset += copy;
821                 if (!(psize -= copy))
822                         goto out;
823
824                 if (skb->len < size_goal || (flags & MSG_OOB))
825                         continue;
826
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);
832                 continue;
833
834 wait_for_sndbuf:
835                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
836 wait_for_memory:
837                 if (copied)
838                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
839
840                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
841                         goto do_error;
842
843                 mss_now = tcp_send_mss(sk, &size_goal, flags);
844         }
845
846 out:
847         if (copied)
848                 tcp_push(sk, flags, mss_now, tp->nonagle);
849         return copied;
850
851 do_error:
852         if (copied)
853                 goto out;
854 out_err:
855         return sk_stream_error(sk, flags, err);
856 }
857
858 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
859                      size_t size, int flags)
860 {
861         ssize_t res;
862         struct sock *sk = sock->sk;
863
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);
867
868         lock_sock(sk);
869         TCP_CHECK_TIMER(sk);
870         res = do_tcp_sendpages(sk, &page, offset, size, flags);
871         TCP_CHECK_TIMER(sk);
872         release_sock(sk);
873         return res;
874 }
875
876 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
877 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
878
879 static inline int select_size(struct sock *sk)
880 {
881         struct tcp_sock *tp = tcp_sk(sk);
882         int tmp = tp->mss_cache;
883
884         if (sk->sk_route_caps & NETIF_F_SG) {
885                 if (sk_can_gso(sk))
886                         tmp = 0;
887                 else {
888                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
889
890                         if (tmp >= pgbreak &&
891                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
892                                 tmp = pgbreak;
893                 }
894         }
895
896         return tmp;
897 }
898
899 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
900                 size_t size)
901 {
902         struct sock *sk = sock->sk;
903         struct iovec *iov;
904         struct tcp_sock *tp = tcp_sk(sk);
905         struct sk_buff *skb;
906         int iovlen, flags;
907         int mss_now, size_goal;
908         int err, copied;
909         long timeo;
910
911         lock_sock(sk);
912         TCP_CHECK_TIMER(sk);
913
914         flags = msg->msg_flags;
915         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
916
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)
920                         goto out_err;
921
922         /* This should be in poll */
923         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
924
925         mss_now = tcp_send_mss(sk, &size_goal, flags);
926
927         /* Ok commence sending. */
928         iovlen = msg->msg_iovlen;
929         iov = msg->msg_iov;
930         copied = 0;
931
932         err = -EPIPE;
933         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
934                 goto out_err;
935
936         while (--iovlen >= 0) {
937                 int seglen = iov->iov_len;
938                 unsigned char __user *from = iov->iov_base;
939
940                 iov++;
941
942                 while (seglen > 0) {
943                         int copy = 0;
944                         int max = size_goal;
945
946                         skb = tcp_write_queue_tail(sk);
947                         if (tcp_send_head(sk)) {
948                                 if (skb->ip_summed == CHECKSUM_NONE)
949                                         max = mss_now;
950                                 copy = max - skb->len;
951                         }
952
953                         if (copy <= 0) {
954 new_segment:
955                                 /* Allocate new segment. If the interface is SG,
956                                  * allocate skb fitting to single page.
957                                  */
958                                 if (!sk_stream_memory_free(sk))
959                                         goto wait_for_sndbuf;
960
961                                 skb = sk_stream_alloc_skb(sk, select_size(sk),
962                                                 sk->sk_allocation);
963                                 if (!skb)
964                                         goto wait_for_memory;
965
966                                 /*
967                                  * Check whether we can use HW checksum.
968                                  */
969                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
970                                         skb->ip_summed = CHECKSUM_PARTIAL;
971
972                                 skb_entail(sk, skb);
973                                 copy = size_goal;
974                                 max = size_goal;
975                         }
976
977                         /* Try to append data to the end of skb. */
978                         if (copy > seglen)
979                                 copy = seglen;
980
981                         /* Where to copy to? */
982                         if (skb_tailroom(skb) > 0) {
983                                 /* We have some space in skb head. Superb! */
984                                 if (copy > skb_tailroom(skb))
985                                         copy = skb_tailroom(skb);
986                                 if ((err = skb_add_data(skb, from, copy)) != 0)
987                                         goto do_fault;
988                         } else {
989                                 int merge = 0;
990                                 int i = skb_shinfo(skb)->nr_frags;
991                                 struct page *page = TCP_PAGE(sk);
992                                 int off = TCP_OFF(sk);
993
994                                 if (skb_can_coalesce(skb, i, page, off) &&
995                                     off != PAGE_SIZE) {
996                                         /* We can extend the last page
997                                          * fragment. */
998                                         merge = 1;
999                                 } else if (i == MAX_SKB_FRAGS ||
1000                                            (!i &&
1001                                            !(sk->sk_route_caps & NETIF_F_SG))) {
1002                                         /* Need to add new fragment and cannot
1003                                          * do this because interface is non-SG,
1004                                          * or because all the page slots are
1005                                          * busy. */
1006                                         tcp_mark_push(tp, skb);
1007                                         goto new_segment;
1008                                 } else if (page) {
1009                                         if (off == PAGE_SIZE) {
1010                                                 put_page(page);
1011                                                 TCP_PAGE(sk) = page = NULL;
1012                                                 off = 0;
1013                                         }
1014                                 } else
1015                                         off = 0;
1016
1017                                 if (copy > PAGE_SIZE - off)
1018                                         copy = PAGE_SIZE - off;
1019
1020                                 if (!sk_wmem_schedule(sk, copy))
1021                                         goto wait_for_memory;
1022
1023                                 if (!page) {
1024                                         /* Allocate new cache page. */
1025                                         if (!(page = sk_stream_alloc_page(sk)))
1026                                                 goto wait_for_memory;
1027                                 }
1028
1029                                 /* Time to copy data. We are close to
1030                                  * the end! */
1031                                 err = skb_copy_to_page(sk, from, skb, page,
1032                                                        off, copy);
1033                                 if (err) {
1034                                         /* If this page was new, give it to the
1035                                          * socket so it does not get leaked.
1036                                          */
1037                                         if (!TCP_PAGE(sk)) {
1038                                                 TCP_PAGE(sk) = page;
1039                                                 TCP_OFF(sk) = 0;
1040                                         }
1041                                         goto do_error;
1042                                 }
1043
1044                                 /* Update the skb. */
1045                                 if (merge) {
1046                                         skb_shinfo(skb)->frags[i - 1].size +=
1047                                                                         copy;
1048                                 } else {
1049                                         skb_fill_page_desc(skb, i, page, off, copy);
1050                                         if (TCP_PAGE(sk)) {
1051                                                 get_page(page);
1052                                         } else if (off + copy < PAGE_SIZE) {
1053                                                 get_page(page);
1054                                                 TCP_PAGE(sk) = page;
1055                                         }
1056                                 }
1057
1058                                 TCP_OFF(sk) = off + copy;
1059                         }
1060
1061                         if (!copied)
1062                                 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1063
1064                         tp->write_seq += copy;
1065                         TCP_SKB_CB(skb)->end_seq += copy;
1066                         skb_shinfo(skb)->gso_segs = 0;
1067
1068                         from += copy;
1069                         copied += copy;
1070                         if ((seglen -= copy) == 0 && iovlen == 0)
1071                                 goto out;
1072
1073                         if (skb->len < max || (flags & MSG_OOB))
1074                                 continue;
1075
1076                         if (forced_push(tp)) {
1077                                 tcp_mark_push(tp, skb);
1078                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1079                         } else if (skb == tcp_send_head(sk))
1080                                 tcp_push_one(sk, mss_now);
1081                         continue;
1082
1083 wait_for_sndbuf:
1084                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1085 wait_for_memory:
1086                         if (copied)
1087                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1088
1089                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1090                                 goto do_error;
1091
1092                         mss_now = tcp_send_mss(sk, &size_goal, flags);
1093                 }
1094         }
1095
1096 out:
1097         if (copied)
1098                 tcp_push(sk, flags, mss_now, tp->nonagle);
1099         TCP_CHECK_TIMER(sk);
1100         release_sock(sk);
1101         return copied;
1102
1103 do_fault:
1104         if (!skb->len) {
1105                 tcp_unlink_write_queue(skb, sk);
1106                 /* It is the one place in all of TCP, except connection
1107                  * reset, where we can be unlinking the send_head.
1108                  */
1109                 tcp_check_send_head(sk, skb);
1110                 sk_wmem_free_skb(sk, skb);
1111         }
1112
1113 do_error:
1114         if (copied)
1115                 goto out;
1116 out_err:
1117         err = sk_stream_error(sk, flags, err);
1118         TCP_CHECK_TIMER(sk);
1119         release_sock(sk);
1120         return err;
1121 }
1122
1123 /*
1124  *      Handle reading urgent data. BSD has very simple semantics for
1125  *      this, no blocking and very strange errors 8)
1126  */
1127
1128 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1129 {
1130         struct tcp_sock *tp = tcp_sk(sk);
1131
1132         /* No URG data to read. */
1133         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1134             tp->urg_data == TCP_URG_READ)
1135                 return -EINVAL; /* Yes this is right ! */
1136
1137         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1138                 return -ENOTCONN;
1139
1140         if (tp->urg_data & TCP_URG_VALID) {
1141                 int err = 0;
1142                 char c = tp->urg_data;
1143
1144                 if (!(flags & MSG_PEEK))
1145                         tp->urg_data = TCP_URG_READ;
1146
1147                 /* Read urgent data. */
1148                 msg->msg_flags |= MSG_OOB;
1149
1150                 if (len > 0) {
1151                         if (!(flags & MSG_TRUNC))
1152                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1153                         len = 1;
1154                 } else
1155                         msg->msg_flags |= MSG_TRUNC;
1156
1157                 return err ? -EFAULT : len;
1158         }
1159
1160         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1161                 return 0;
1162
1163         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1164          * the available implementations agree in this case:
1165          * this call should never block, independent of the
1166          * blocking state of the socket.
1167          * Mike <pall@rz.uni-karlsruhe.de>
1168          */
1169         return -EAGAIN;
1170 }
1171
1172 /* Clean up the receive buffer for full frames taken by the user,
1173  * then send an ACK if necessary.  COPIED is the number of bytes
1174  * tcp_recvmsg has given to the user so far, it speeds up the
1175  * calculation of whether or not we must ACK for the sake of
1176  * a window update.
1177  */
1178 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1179 {
1180         struct tcp_sock *tp = tcp_sk(sk);
1181         int time_to_ack = 0;
1182
1183 #if TCP_DEBUG
1184         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1185
1186         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1187              KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1188              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1189 #endif
1190
1191         if (inet_csk_ack_scheduled(sk)) {
1192                 const struct inet_connection_sock *icsk = inet_csk(sk);
1193                    /* Delayed ACKs frequently hit locked sockets during bulk
1194                     * receive. */
1195                 if (icsk->icsk_ack.blocked ||
1196                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
1197                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1198                     /*
1199                      * If this read emptied read buffer, we send ACK, if
1200                      * connection is not bidirectional, user drained
1201                      * receive buffer and there was a small segment
1202                      * in queue.
1203                      */
1204                     (copied > 0 &&
1205                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1206                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1207                        !icsk->icsk_ack.pingpong)) &&
1208                       !atomic_read(&sk->sk_rmem_alloc)))
1209                         time_to_ack = 1;
1210         }
1211
1212         /* We send an ACK if we can now advertise a non-zero window
1213          * which has been raised "significantly".
1214          *
1215          * Even if window raised up to infinity, do not send window open ACK
1216          * in states, where we will not receive more. It is useless.
1217          */
1218         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1219                 __u32 rcv_window_now = tcp_receive_window(tp);
1220
1221                 /* Optimize, __tcp_select_window() is not cheap. */
1222                 if (2*rcv_window_now <= tp->window_clamp) {
1223                         __u32 new_window = __tcp_select_window(sk);
1224
1225                         /* Send ACK now, if this read freed lots of space
1226                          * in our buffer. Certainly, new_window is new window.
1227                          * We can advertise it now, if it is not less than current one.
1228                          * "Lots" means "at least twice" here.
1229                          */
1230                         if (new_window && new_window >= 2 * rcv_window_now)
1231                                 time_to_ack = 1;
1232                 }
1233         }
1234         if (time_to_ack)
1235                 tcp_send_ack(sk);
1236 }
1237
1238 static void tcp_prequeue_process(struct sock *sk)
1239 {
1240         struct sk_buff *skb;
1241         struct tcp_sock *tp = tcp_sk(sk);
1242
1243         NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1244
1245         /* RX process wants to run with disabled BHs, though it is not
1246          * necessary */
1247         local_bh_disable();
1248         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1249                 sk_backlog_rcv(sk, skb);
1250         local_bh_enable();
1251
1252         /* Clear memory counter. */
1253         tp->ucopy.memory = 0;
1254 }
1255
1256 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1257 {
1258         struct sk_buff *skb;
1259         u32 offset;
1260
1261         skb_queue_walk(&sk->sk_receive_queue, skb) {
1262                 offset = seq - TCP_SKB_CB(skb)->seq;
1263                 if (tcp_hdr(skb)->syn)
1264                         offset--;
1265                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1266                         *off = offset;
1267                         return skb;
1268                 }
1269         }
1270         return NULL;
1271 }
1272
1273 /*
1274  * This routine provides an alternative to tcp_recvmsg() for routines
1275  * that would like to handle copying from skbuffs directly in 'sendfile'
1276  * fashion.
1277  * Note:
1278  *      - It is assumed that the socket was locked by the caller.
1279  *      - The routine does not block.
1280  *      - At present, there is no support for reading OOB data
1281  *        or for 'peeking' the socket using this routine
1282  *        (although both would be easy to implement).
1283  */
1284 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1285                   sk_read_actor_t recv_actor)
1286 {
1287         struct sk_buff *skb;
1288         struct tcp_sock *tp = tcp_sk(sk);
1289         u32 seq = tp->copied_seq;
1290         u32 offset;
1291         int copied = 0;
1292
1293         if (sk->sk_state == TCP_LISTEN)
1294                 return -ENOTCONN;
1295         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1296                 if (offset < skb->len) {
1297                         int used;
1298                         size_t len;
1299
1300                         len = skb->len - offset;
1301                         /* Stop reading if we hit a patch of urgent data */
1302                         if (tp->urg_data) {
1303                                 u32 urg_offset = tp->urg_seq - seq;
1304                                 if (urg_offset < len)
1305                                         len = urg_offset;
1306                                 if (!len)
1307                                         break;
1308                         }
1309                         used = recv_actor(desc, skb, offset, len);
1310                         if (used < 0) {
1311                                 if (!copied)
1312                                         copied = used;
1313                                 break;
1314                         } else if (used <= len) {
1315                                 seq += used;
1316                                 copied += used;
1317                                 offset += used;
1318                         }
1319                         /*
1320                          * If recv_actor drops the lock (e.g. TCP splice
1321                          * receive) the skb pointer might be invalid when
1322                          * getting here: tcp_collapse might have deleted it
1323                          * while aggregating skbs from the socket queue.
1324                          */
1325                         skb = tcp_recv_skb(sk, seq-1, &offset);
1326                         if (!skb || (offset+1 != skb->len))
1327                                 break;
1328                 }
1329                 if (tcp_hdr(skb)->fin) {
1330                         sk_eat_skb(sk, skb, 0);
1331                         ++seq;
1332                         break;
1333                 }
1334                 sk_eat_skb(sk, skb, 0);
1335                 if (!desc->count)
1336                         break;
1337         }
1338         tp->copied_seq = seq;
1339
1340         tcp_rcv_space_adjust(sk);
1341
1342         /* Clean up data we have read: This will do ACK frames. */
1343         if (copied > 0)
1344                 tcp_cleanup_rbuf(sk, copied);
1345         return copied;
1346 }
1347
1348 /*
1349  *      This routine copies from a sock struct into the user buffer.
1350  *
1351  *      Technical note: in 2.3 we work on _locked_ socket, so that
1352  *      tricks with *seq access order and skb->users are not required.
1353  *      Probably, code can be easily improved even more.
1354  */
1355
1356 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1357                 size_t len, int nonblock, int flags, int *addr_len)
1358 {
1359         struct tcp_sock *tp = tcp_sk(sk);
1360         int copied = 0;
1361         u32 peek_seq;
1362         u32 *seq;
1363         unsigned long used;
1364         int err;
1365         int target;             /* Read at least this many bytes */
1366         long timeo;
1367         struct task_struct *user_recv = NULL;
1368         int copied_early = 0;
1369         struct sk_buff *skb;
1370         u32 urg_hole = 0;
1371
1372         lock_sock(sk);
1373
1374         TCP_CHECK_TIMER(sk);
1375
1376         err = -ENOTCONN;
1377         if (sk->sk_state == TCP_LISTEN)
1378                 goto out;
1379
1380         timeo = sock_rcvtimeo(sk, nonblock);
1381
1382         /* Urgent data needs to be handled specially. */
1383         if (flags & MSG_OOB)
1384                 goto recv_urg;
1385
1386         seq = &tp->copied_seq;
1387         if (flags & MSG_PEEK) {
1388                 peek_seq = tp->copied_seq;
1389                 seq = &peek_seq;
1390         }
1391
1392         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1393
1394 #ifdef CONFIG_NET_DMA
1395         tp->ucopy.dma_chan = NULL;
1396         preempt_disable();
1397         skb = skb_peek_tail(&sk->sk_receive_queue);
1398         {
1399                 int available = 0;
1400
1401                 if (skb)
1402                         available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1403                 if ((available < target) &&
1404                     (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1405                     !sysctl_tcp_low_latency &&
1406                     dma_find_channel(DMA_MEMCPY)) {
1407                         preempt_enable_no_resched();
1408                         tp->ucopy.pinned_list =
1409                                         dma_pin_iovec_pages(msg->msg_iov, len);
1410                 } else {
1411                         preempt_enable_no_resched();
1412                 }
1413         }
1414 #endif
1415
1416         do {
1417                 u32 offset;
1418
1419                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1420                 if (tp->urg_data && tp->urg_seq == *seq) {
1421                         if (copied)
1422                                 break;
1423                         if (signal_pending(current)) {
1424                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1425                                 break;
1426                         }
1427                 }
1428
1429                 /* Next get a buffer. */
1430
1431                 skb_queue_walk(&sk->sk_receive_queue, skb) {
1432                         /* Now that we have two receive queues this
1433                          * shouldn't happen.
1434                          */
1435                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1436                              KERN_INFO "recvmsg bug: copied %X "
1437                                        "seq %X rcvnxt %X fl %X\n", *seq,
1438                                        TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1439                                        flags))
1440                                 break;
1441
1442                         offset = *seq - TCP_SKB_CB(skb)->seq;
1443                         if (tcp_hdr(skb)->syn)
1444                                 offset--;
1445                         if (offset < skb->len)
1446                                 goto found_ok_skb;
1447                         if (tcp_hdr(skb)->fin)
1448                                 goto found_fin_ok;
1449                         WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1450                                         "copied %X seq %X rcvnxt %X fl %X\n",
1451                                         *seq, TCP_SKB_CB(skb)->seq,
1452                                         tp->rcv_nxt, flags);
1453                 }
1454
1455                 /* Well, if we have backlog, try to process it now yet. */
1456
1457                 if (copied >= target && !sk->sk_backlog.tail)
1458                         break;
1459
1460                 if (copied) {
1461                         if (sk->sk_err ||
1462                             sk->sk_state == TCP_CLOSE ||
1463                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1464                             !timeo ||
1465                             signal_pending(current))
1466                                 break;
1467                 } else {
1468                         if (sock_flag(sk, SOCK_DONE))
1469                                 break;
1470
1471                         if (sk->sk_err) {
1472                                 copied = sock_error(sk);
1473                                 break;
1474                         }
1475
1476                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1477                                 break;
1478
1479                         if (sk->sk_state == TCP_CLOSE) {
1480                                 if (!sock_flag(sk, SOCK_DONE)) {
1481                                         /* This occurs when user tries to read
1482                                          * from never connected socket.
1483                                          */
1484                                         copied = -ENOTCONN;
1485                                         break;
1486                                 }
1487                                 break;
1488                         }
1489
1490                         if (!timeo) {
1491                                 copied = -EAGAIN;
1492                                 break;
1493                         }
1494
1495                         if (signal_pending(current)) {
1496                                 copied = sock_intr_errno(timeo);
1497                                 break;
1498                         }
1499                 }
1500
1501                 tcp_cleanup_rbuf(sk, copied);
1502
1503                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1504                         /* Install new reader */
1505                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1506                                 user_recv = current;
1507                                 tp->ucopy.task = user_recv;
1508                                 tp->ucopy.iov = msg->msg_iov;
1509                         }
1510
1511                         tp->ucopy.len = len;
1512
1513                         WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1514                                 !(flags & (MSG_PEEK | MSG_TRUNC)));
1515
1516                         /* Ugly... If prequeue is not empty, we have to
1517                          * process it before releasing socket, otherwise
1518                          * order will be broken at second iteration.
1519                          * More elegant solution is required!!!
1520                          *
1521                          * Look: we have the following (pseudo)queues:
1522                          *
1523                          * 1. packets in flight
1524                          * 2. backlog
1525                          * 3. prequeue
1526                          * 4. receive_queue
1527                          *
1528                          * Each queue can be processed only if the next ones
1529                          * are empty. At this point we have empty receive_queue.
1530                          * But prequeue _can_ be not empty after 2nd iteration,
1531                          * when we jumped to start of loop because backlog
1532                          * processing added something to receive_queue.
1533                          * We cannot release_sock(), because backlog contains
1534                          * packets arrived _after_ prequeued ones.
1535                          *
1536                          * Shortly, algorithm is clear --- to process all
1537                          * the queues in order. We could make it more directly,
1538                          * requeueing packets from backlog to prequeue, if
1539                          * is not empty. It is more elegant, but eats cycles,
1540                          * unfortunately.
1541                          */
1542                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1543                                 goto do_prequeue;
1544
1545                         /* __ Set realtime policy in scheduler __ */
1546                 }
1547
1548                 if (copied >= target) {
1549                         /* Do not sleep, just process backlog. */
1550                         release_sock(sk);
1551                         lock_sock(sk);
1552                 } else
1553                         sk_wait_data(sk, &timeo);
1554
1555 #ifdef CONFIG_NET_DMA
1556                 tp->ucopy.wakeup = 0;
1557 #endif
1558
1559                 if (user_recv) {
1560                         int chunk;
1561
1562                         /* __ Restore normal policy in scheduler __ */
1563
1564                         if ((chunk = len - tp->ucopy.len) != 0) {
1565                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1566                                 len -= chunk;
1567                                 copied += chunk;
1568                         }
1569
1570                         if (tp->rcv_nxt == tp->copied_seq &&
1571                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1572 do_prequeue:
1573                                 tcp_prequeue_process(sk);
1574
1575                                 if ((chunk = len - tp->ucopy.len) != 0) {
1576                                         NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1577                                         len -= chunk;
1578                                         copied += chunk;
1579                                 }
1580                         }
1581                 }
1582                 if ((flags & MSG_PEEK) &&
1583                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
1584                         if (net_ratelimit())
1585                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1586                                        current->comm, task_pid_nr(current));
1587                         peek_seq = tp->copied_seq;
1588                 }
1589                 continue;
1590
1591         found_ok_skb:
1592                 /* Ok so how much can we use? */
1593                 used = skb->len - offset;
1594                 if (len < used)
1595                         used = len;
1596
1597                 /* Do we have urgent data here? */
1598                 if (tp->urg_data) {
1599                         u32 urg_offset = tp->urg_seq - *seq;
1600                         if (urg_offset < used) {
1601                                 if (!urg_offset) {
1602                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1603                                                 ++*seq;
1604                                                 urg_hole++;
1605                                                 offset++;
1606                                                 used--;
1607                                                 if (!used)
1608                                                         goto skip_copy;
1609                                         }
1610                                 } else
1611                                         used = urg_offset;
1612                         }
1613                 }
1614
1615                 if (!(flags & MSG_TRUNC)) {
1616 #ifdef CONFIG_NET_DMA
1617                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1618                                 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1619
1620                         if (tp->ucopy.dma_chan) {
1621                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1622                                         tp->ucopy.dma_chan, skb, offset,
1623                                         msg->msg_iov, used,
1624                                         tp->ucopy.pinned_list);
1625
1626                                 if (tp->ucopy.dma_cookie < 0) {
1627
1628                                         printk(KERN_ALERT "dma_cookie < 0\n");
1629
1630                                         /* Exception. Bailout! */
1631                                         if (!copied)
1632                                                 copied = -EFAULT;
1633                                         break;
1634                                 }
1635                                 if ((offset + used) == skb->len)
1636                                         copied_early = 1;
1637
1638                         } else
1639 #endif
1640                         {
1641                                 err = skb_copy_datagram_iovec(skb, offset,
1642                                                 msg->msg_iov, used);
1643                                 if (err) {
1644                                         /* Exception. Bailout! */
1645                                         if (!copied)
1646                                                 copied = -EFAULT;
1647                                         break;
1648                                 }
1649                         }
1650                 }
1651
1652                 *seq += used;
1653                 copied += used;
1654                 len -= used;
1655
1656                 tcp_rcv_space_adjust(sk);
1657
1658 skip_copy:
1659                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1660                         tp->urg_data = 0;
1661                         tcp_fast_path_check(sk);
1662                 }
1663                 if (used + offset < skb->len)
1664                         continue;
1665
1666                 if (tcp_hdr(skb)->fin)
1667                         goto found_fin_ok;
1668                 if (!(flags & MSG_PEEK)) {
1669                         sk_eat_skb(sk, skb, copied_early);
1670                         copied_early = 0;
1671                 }
1672                 continue;
1673
1674         found_fin_ok:
1675                 /* Process the FIN. */
1676                 ++*seq;
1677                 if (!(flags & MSG_PEEK)) {
1678                         sk_eat_skb(sk, skb, copied_early);
1679                         copied_early = 0;
1680                 }
1681                 break;
1682         } while (len > 0);
1683
1684         if (user_recv) {
1685                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1686                         int chunk;
1687
1688                         tp->ucopy.len = copied > 0 ? len : 0;
1689
1690                         tcp_prequeue_process(sk);
1691
1692                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1693                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1694                                 len -= chunk;
1695                                 copied += chunk;
1696                         }
1697                 }
1698
1699                 tp->ucopy.task = NULL;
1700                 tp->ucopy.len = 0;
1701         }
1702
1703 #ifdef CONFIG_NET_DMA
1704         if (tp->ucopy.dma_chan) {
1705                 dma_cookie_t done, used;
1706
1707                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1708
1709                 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1710                                                  tp->ucopy.dma_cookie, &done,
1711                                                  &used) == DMA_IN_PROGRESS) {
1712                         /* do partial cleanup of sk_async_wait_queue */
1713                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1714                                (dma_async_is_complete(skb->dma_cookie, done,
1715                                                       used) == DMA_SUCCESS)) {
1716                                 __skb_dequeue(&sk->sk_async_wait_queue);
1717                                 kfree_skb(skb);
1718                         }
1719                 }
1720
1721                 /* Safe to free early-copied skbs now */
1722                 __skb_queue_purge(&sk->sk_async_wait_queue);
1723                 tp->ucopy.dma_chan = NULL;
1724         }
1725         if (tp->ucopy.pinned_list) {
1726                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1727                 tp->ucopy.pinned_list = NULL;
1728         }
1729 #endif
1730
1731         /* According to UNIX98, msg_name/msg_namelen are ignored
1732          * on connected socket. I was just happy when found this 8) --ANK
1733          */
1734
1735         /* Clean up data we have read: This will do ACK frames. */
1736         tcp_cleanup_rbuf(sk, copied);
1737
1738         TCP_CHECK_TIMER(sk);
1739         release_sock(sk);
1740         return copied;
1741
1742 out:
1743         TCP_CHECK_TIMER(sk);
1744         release_sock(sk);
1745         return err;
1746
1747 recv_urg:
1748         err = tcp_recv_urg(sk, msg, len, flags);
1749         goto out;
1750 }
1751
1752 void tcp_set_state(struct sock *sk, int state)
1753 {
1754         int oldstate = sk->sk_state;
1755
1756         switch (state) {
1757         case TCP_ESTABLISHED:
1758                 if (oldstate != TCP_ESTABLISHED)
1759                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1760                 break;
1761
1762         case TCP_CLOSE:
1763                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1764                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1765
1766                 sk->sk_prot->unhash(sk);
1767                 if (inet_csk(sk)->icsk_bind_hash &&
1768                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1769                         inet_put_port(sk);
1770                 /* fall through */
1771         default:
1772                 if (oldstate == TCP_ESTABLISHED)
1773                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1774         }
1775
1776         /* Change state AFTER socket is unhashed to avoid closed
1777          * socket sitting in hash tables.
1778          */
1779         sk->sk_state = state;
1780
1781 #ifdef STATE_TRACE
1782         SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1783 #endif
1784 }
1785 EXPORT_SYMBOL_GPL(tcp_set_state);
1786
1787 /*
1788  *      State processing on a close. This implements the state shift for
1789  *      sending our FIN frame. Note that we only send a FIN for some
1790  *      states. A shutdown() may have already sent the FIN, or we may be
1791  *      closed.
1792  */
1793
1794 static const unsigned char new_state[16] = {
1795   /* current state:        new state:      action:      */
1796   /* (Invalid)          */ TCP_CLOSE,
1797   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1798   /* TCP_SYN_SENT       */ TCP_CLOSE,
1799   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1800   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1801   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1802   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1803   /* TCP_CLOSE          */ TCP_CLOSE,
1804   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1805   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1806   /* TCP_LISTEN         */ TCP_CLOSE,
1807   /* TCP_CLOSING        */ TCP_CLOSING,
1808 };
1809
1810 static int tcp_close_state(struct sock *sk)
1811 {
1812         int next = (int)new_state[sk->sk_state];
1813         int ns = next & TCP_STATE_MASK;
1814
1815         tcp_set_state(sk, ns);
1816
1817         return next & TCP_ACTION_FIN;
1818 }
1819
1820 /*
1821  *      Shutdown the sending side of a connection. Much like close except
1822  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1823  */
1824
1825 void tcp_shutdown(struct sock *sk, int how)
1826 {
1827         /*      We need to grab some memory, and put together a FIN,
1828          *      and then put it into the queue to be sent.
1829          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1830          */
1831         if (!(how & SEND_SHUTDOWN))
1832                 return;
1833
1834         /* If we've already sent a FIN, or it's a closed state, skip this. */
1835         if ((1 << sk->sk_state) &
1836             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1837              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1838                 /* Clear out any half completed packets.  FIN if needed. */
1839                 if (tcp_close_state(sk))
1840                         tcp_send_fin(sk);
1841         }
1842 }
1843
1844 void tcp_close(struct sock *sk, long timeout)
1845 {
1846         struct sk_buff *skb;
1847         int data_was_unread = 0;
1848         int state;
1849
1850         lock_sock(sk);
1851         sk->sk_shutdown = SHUTDOWN_MASK;
1852
1853         if (sk->sk_state == TCP_LISTEN) {
1854                 tcp_set_state(sk, TCP_CLOSE);
1855
1856                 /* Special case. */
1857                 inet_csk_listen_stop(sk);
1858
1859                 goto adjudge_to_death;
1860         }
1861
1862         /*  We need to flush the recv. buffs.  We do this only on the
1863          *  descriptor close, not protocol-sourced closes, because the
1864          *  reader process may not have drained the data yet!
1865          */
1866         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1867                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1868                           tcp_hdr(skb)->fin;
1869                 data_was_unread += len;
1870                 __kfree_skb(skb);
1871         }
1872
1873         sk_mem_reclaim(sk);
1874
1875         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1876          * data was lost. To witness the awful effects of the old behavior of
1877          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1878          * GET in an FTP client, suspend the process, wait for the client to
1879          * advertise a zero window, then kill -9 the FTP client, wheee...
1880          * Note: timeout is always zero in such a case.
1881          */
1882         if (data_was_unread) {
1883                 /* Unread data was tossed, zap the connection. */
1884                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1885                 tcp_set_state(sk, TCP_CLOSE);
1886                 tcp_send_active_reset(sk, sk->sk_allocation);
1887         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1888                 /* Check zero linger _after_ checking for unread data. */
1889                 sk->sk_prot->disconnect(sk, 0);
1890                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1891         } else if (tcp_close_state(sk)) {
1892                 /* We FIN if the application ate all the data before
1893                  * zapping the connection.
1894                  */
1895
1896                 /* RED-PEN. Formally speaking, we have broken TCP state
1897                  * machine. State transitions:
1898                  *
1899                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1900                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1901                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1902                  *
1903                  * are legal only when FIN has been sent (i.e. in window),
1904                  * rather than queued out of window. Purists blame.
1905                  *
1906                  * F.e. "RFC state" is ESTABLISHED,
1907                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1908                  *
1909                  * The visible declinations are that sometimes
1910                  * we enter time-wait state, when it is not required really
1911                  * (harmless), do not send active resets, when they are
1912                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1913                  * they look as CLOSING or LAST_ACK for Linux)
1914                  * Probably, I missed some more holelets.
1915                  *                                              --ANK
1916                  */
1917                 tcp_send_fin(sk);
1918         }
1919
1920         sk_stream_wait_close(sk, timeout);
1921
1922 adjudge_to_death:
1923         state = sk->sk_state;
1924         sock_hold(sk);
1925         sock_orphan(sk);
1926
1927         /* It is the last release_sock in its life. It will remove backlog. */
1928         release_sock(sk);
1929
1930
1931         /* Now socket is owned by kernel and we acquire BH lock
1932            to finish close. No need to check for user refs.
1933          */
1934         local_bh_disable();
1935         bh_lock_sock(sk);
1936         WARN_ON(sock_owned_by_user(sk));
1937
1938         percpu_counter_inc(sk->sk_prot->orphan_count);
1939
1940         /* Have we already been destroyed by a softirq or backlog? */
1941         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1942                 goto out;
1943
1944         /*      This is a (useful) BSD violating of the RFC. There is a
1945          *      problem with TCP as specified in that the other end could
1946          *      keep a socket open forever with no application left this end.
1947          *      We use a 3 minute timeout (about the same as BSD) then kill
1948          *      our end. If they send after that then tough - BUT: long enough
1949          *      that we won't make the old 4*rto = almost no time - whoops
1950          *      reset mistake.
1951          *
1952          *      Nope, it was not mistake. It is really desired behaviour
1953          *      f.e. on http servers, when such sockets are useless, but
1954          *      consume significant resources. Let's do it with special
1955          *      linger2 option.                                 --ANK
1956          */
1957
1958         if (sk->sk_state == TCP_FIN_WAIT2) {
1959                 struct tcp_sock *tp = tcp_sk(sk);
1960                 if (tp->linger2 < 0) {
1961                         tcp_set_state(sk, TCP_CLOSE);
1962                         tcp_send_active_reset(sk, GFP_ATOMIC);
1963                         NET_INC_STATS_BH(sock_net(sk),
1964                                         LINUX_MIB_TCPABORTONLINGER);
1965                 } else {
1966                         const int tmo = tcp_fin_time(sk);
1967
1968                         if (tmo > TCP_TIMEWAIT_LEN) {
1969                                 inet_csk_reset_keepalive_timer(sk,
1970                                                 tmo - TCP_TIMEWAIT_LEN);
1971                         } else {
1972                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1973                                 goto out;
1974                         }
1975                 }
1976         }
1977         if (sk->sk_state != TCP_CLOSE) {
1978                 int orphan_count = percpu_counter_read_positive(
1979                                                 sk->sk_prot->orphan_count);
1980
1981                 sk_mem_reclaim(sk);
1982                 if (tcp_too_many_orphans(sk, orphan_count)) {
1983                         if (net_ratelimit())
1984                                 printk(KERN_INFO "TCP: too many of orphaned "
1985                                        "sockets\n");
1986                         tcp_set_state(sk, TCP_CLOSE);
1987                         tcp_send_active_reset(sk, GFP_ATOMIC);
1988                         NET_INC_STATS_BH(sock_net(sk),
1989                                         LINUX_MIB_TCPABORTONMEMORY);
1990                 }
1991         }
1992
1993         if (sk->sk_state == TCP_CLOSE)
1994                 inet_csk_destroy_sock(sk);
1995         /* Otherwise, socket is reprieved until protocol close. */
1996
1997 out:
1998         bh_unlock_sock(sk);
1999         local_bh_enable();
2000         sock_put(sk);
2001 }
2002
2003 /* These states need RST on ABORT according to RFC793 */
2004
2005 static inline int tcp_need_reset(int state)
2006 {
2007         return (1 << state) &
2008                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2009                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2010 }
2011
2012 int tcp_disconnect(struct sock *sk, int flags)
2013 {
2014         struct inet_sock *inet = inet_sk(sk);
2015         struct inet_connection_sock *icsk = inet_csk(sk);
2016         struct tcp_sock *tp = tcp_sk(sk);
2017         int err = 0;
2018         int old_state = sk->sk_state;
2019
2020         if (old_state != TCP_CLOSE)
2021                 tcp_set_state(sk, TCP_CLOSE);
2022
2023         /* ABORT function of RFC793 */
2024         if (old_state == TCP_LISTEN) {
2025                 inet_csk_listen_stop(sk);
2026         } else if (tcp_need_reset(old_state) ||
2027                    (tp->snd_nxt != tp->write_seq &&
2028                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2029                 /* The last check adjusts for discrepancy of Linux wrt. RFC
2030                  * states
2031                  */
2032                 tcp_send_active_reset(sk, gfp_any());
2033                 sk->sk_err = ECONNRESET;
2034         } else if (old_state == TCP_SYN_SENT)
2035                 sk->sk_err = ECONNRESET;
2036
2037         tcp_clear_xmit_timers(sk);
2038         __skb_queue_purge(&sk->sk_receive_queue);
2039         tcp_write_queue_purge(sk);
2040         __skb_queue_purge(&tp->out_of_order_queue);
2041 #ifdef CONFIG_NET_DMA
2042         __skb_queue_purge(&sk->sk_async_wait_queue);
2043 #endif
2044
2045         inet->inet_dport = 0;
2046
2047         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2048                 inet_reset_saddr(sk);
2049
2050         sk->sk_shutdown = 0;
2051         sock_reset_flag(sk, SOCK_DONE);
2052         tp->srtt = 0;
2053         if ((tp->write_seq += tp->max_window + 2) == 0)
2054                 tp->write_seq = 1;
2055         icsk->icsk_backoff = 0;
2056         tp->snd_cwnd = 2;
2057         icsk->icsk_probes_out = 0;
2058         tp->packets_out = 0;
2059         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2060         tp->snd_cwnd_cnt = 0;
2061         tp->bytes_acked = 0;
2062         tp->window_clamp = 0;
2063         tcp_set_ca_state(sk, TCP_CA_Open);
2064         tcp_clear_retrans(tp);
2065         inet_csk_delack_init(sk);
2066         tcp_init_send_head(sk);
2067         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2068         __sk_dst_reset(sk);
2069
2070         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2071
2072         sk->sk_error_report(sk);
2073         return err;
2074 }
2075
2076 /*
2077  *      Socket option code for TCP.
2078  */
2079 static int do_tcp_setsockopt(struct sock *sk, int level,
2080                 int optname, char __user *optval, unsigned int optlen)
2081 {
2082         struct tcp_sock *tp = tcp_sk(sk);
2083         struct inet_connection_sock *icsk = inet_csk(sk);
2084         int val;
2085         int err = 0;
2086
2087         /* These are data/string values, all the others are ints */
2088         switch (optname) {
2089         case TCP_CONGESTION: {
2090                 char name[TCP_CA_NAME_MAX];
2091
2092                 if (optlen < 1)
2093                         return -EINVAL;
2094
2095                 val = strncpy_from_user(name, optval,
2096                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
2097                 if (val < 0)
2098                         return -EFAULT;
2099                 name[val] = 0;
2100
2101                 lock_sock(sk);
2102                 err = tcp_set_congestion_control(sk, name);
2103                 release_sock(sk);
2104                 return err;
2105         }
2106         case TCP_COOKIE_TRANSACTIONS: {
2107                 struct tcp_cookie_transactions ctd;
2108                 struct tcp_cookie_values *cvp = NULL;
2109
2110                 if (sizeof(ctd) > optlen)
2111                         return -EINVAL;
2112                 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2113                         return -EFAULT;
2114
2115                 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2116                     ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2117                         return -EINVAL;
2118
2119                 if (ctd.tcpct_cookie_desired == 0) {
2120                         /* default to global value */
2121                 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2122                            ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2123                            ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2124                         return -EINVAL;
2125                 }
2126
2127                 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2128                         /* Supercedes all other values */
2129                         lock_sock(sk);
2130                         if (tp->cookie_values != NULL) {
2131                                 kref_put(&tp->cookie_values->kref,
2132                                          tcp_cookie_values_release);
2133                                 tp->cookie_values = NULL;
2134                         }
2135                         tp->rx_opt.cookie_in_always = 0; /* false */
2136                         tp->rx_opt.cookie_out_never = 1; /* true */
2137                         release_sock(sk);
2138                         return err;
2139                 }
2140
2141                 /* Allocate ancillary memory before locking.
2142                  */
2143                 if (ctd.tcpct_used > 0 ||
2144                     (tp->cookie_values == NULL &&
2145                      (sysctl_tcp_cookie_size > 0 ||
2146                       ctd.tcpct_cookie_desired > 0 ||
2147                       ctd.tcpct_s_data_desired > 0))) {
2148                         cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2149                                       GFP_KERNEL);
2150                         if (cvp == NULL)
2151                                 return -ENOMEM;
2152                 }
2153                 lock_sock(sk);
2154                 tp->rx_opt.cookie_in_always =
2155                         (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2156                 tp->rx_opt.cookie_out_never = 0; /* false */
2157
2158                 if (tp->cookie_values != NULL) {
2159                         if (cvp != NULL) {
2160                                 /* Changed values are recorded by a changed
2161                                  * pointer, ensuring the cookie will differ,
2162                                  * without separately hashing each value later.
2163                                  */
2164                                 kref_put(&tp->cookie_values->kref,
2165                                          tcp_cookie_values_release);
2166                                 kref_init(&cvp->kref);
2167                                 tp->cookie_values = cvp;
2168                         } else {
2169                                 cvp = tp->cookie_values;
2170                         }
2171                 }
2172                 if (cvp != NULL) {
2173                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
2174
2175                         if (ctd.tcpct_used > 0) {
2176                                 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2177                                        ctd.tcpct_used);
2178                                 cvp->s_data_desired = ctd.tcpct_used;
2179                                 cvp->s_data_constant = 1; /* true */
2180                         } else {
2181                                 /* No constant payload data. */
2182                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2183                                 cvp->s_data_constant = 0; /* false */
2184                         }
2185                 }
2186                 release_sock(sk);
2187                 return err;
2188         }
2189         default:
2190                 /* fallthru */
2191                 break;
2192         };
2193
2194         if (optlen < sizeof(int))
2195                 return -EINVAL;
2196
2197         if (get_user(val, (int __user *)optval))
2198                 return -EFAULT;
2199
2200         lock_sock(sk);
2201
2202         switch (optname) {
2203         case TCP_MAXSEG:
2204                 /* Values greater than interface MTU won't take effect. However
2205                  * at the point when this call is done we typically don't yet
2206                  * know which interface is going to be used */
2207                 if (val < 8 || val > MAX_TCP_WINDOW) {
2208                         err = -EINVAL;
2209                         break;
2210                 }
2211                 tp->rx_opt.user_mss = val;
2212                 break;
2213
2214         case TCP_NODELAY:
2215                 if (val) {
2216                         /* TCP_NODELAY is weaker than TCP_CORK, so that
2217                          * this option on corked socket is remembered, but
2218                          * it is not activated until cork is cleared.
2219                          *
2220                          * However, when TCP_NODELAY is set we make
2221                          * an explicit push, which overrides even TCP_CORK
2222                          * for currently queued segments.
2223                          */
2224                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2225                         tcp_push_pending_frames(sk);
2226                 } else {
2227                         tp->nonagle &= ~TCP_NAGLE_OFF;
2228                 }
2229                 break;
2230
2231         case TCP_CORK:
2232                 /* When set indicates to always queue non-full frames.
2233                  * Later the user clears this option and we transmit
2234                  * any pending partial frames in the queue.  This is
2235                  * meant to be used alongside sendfile() to get properly
2236                  * filled frames when the user (for example) must write
2237                  * out headers with a write() call first and then use
2238                  * sendfile to send out the data parts.
2239                  *
2240                  * TCP_CORK can be set together with TCP_NODELAY and it is
2241                  * stronger than TCP_NODELAY.
2242                  */
2243                 if (val) {
2244                         tp->nonagle |= TCP_NAGLE_CORK;
2245                 } else {
2246                         tp->nonagle &= ~TCP_NAGLE_CORK;
2247                         if (tp->nonagle&TCP_NAGLE_OFF)
2248                                 tp->nonagle |= TCP_NAGLE_PUSH;
2249                         tcp_push_pending_frames(sk);
2250                 }
2251                 break;
2252
2253         case TCP_KEEPIDLE:
2254                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2255                         err = -EINVAL;
2256                 else {
2257                         tp->keepalive_time = val * HZ;
2258                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
2259                             !((1 << sk->sk_state) &
2260                               (TCPF_CLOSE | TCPF_LISTEN))) {
2261                                 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2262                                 if (tp->keepalive_time > elapsed)
2263                                         elapsed = tp->keepalive_time - elapsed;
2264                                 else
2265                                         elapsed = 0;
2266                                 inet_csk_reset_keepalive_timer(sk, elapsed);
2267                         }
2268                 }
2269                 break;
2270         case TCP_KEEPINTVL:
2271                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2272                         err = -EINVAL;
2273                 else
2274                         tp->keepalive_intvl = val * HZ;
2275                 break;
2276         case TCP_KEEPCNT:
2277                 if (val < 1 || val > MAX_TCP_KEEPCNT)
2278                         err = -EINVAL;
2279                 else
2280                         tp->keepalive_probes = val;
2281                 break;
2282         case TCP_SYNCNT:
2283                 if (val < 1 || val > MAX_TCP_SYNCNT)
2284                         err = -EINVAL;
2285                 else
2286                         icsk->icsk_syn_retries = val;
2287                 break;
2288
2289         case TCP_LINGER2:
2290                 if (val < 0)
2291                         tp->linger2 = -1;
2292                 else if (val > sysctl_tcp_fin_timeout / HZ)
2293                         tp->linger2 = 0;
2294                 else
2295                         tp->linger2 = val * HZ;
2296                 break;
2297
2298         case TCP_DEFER_ACCEPT:
2299                 /* Translate value in seconds to number of retransmits */
2300                 icsk->icsk_accept_queue.rskq_defer_accept =
2301                         secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2302                                         TCP_RTO_MAX / HZ);
2303                 break;
2304
2305         case TCP_WINDOW_CLAMP:
2306                 if (!val) {
2307                         if (sk->sk_state != TCP_CLOSE) {
2308                                 err = -EINVAL;
2309                                 break;
2310                         }
2311                         tp->window_clamp = 0;
2312                 } else
2313                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2314                                                 SOCK_MIN_RCVBUF / 2 : val;
2315                 break;
2316
2317         case TCP_QUICKACK:
2318                 if (!val) {
2319                         icsk->icsk_ack.pingpong = 1;
2320                 } else {
2321                         icsk->icsk_ack.pingpong = 0;
2322                         if ((1 << sk->sk_state) &
2323                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2324                             inet_csk_ack_scheduled(sk)) {
2325                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2326                                 tcp_cleanup_rbuf(sk, 1);
2327                                 if (!(val & 1))
2328                                         icsk->icsk_ack.pingpong = 1;
2329                         }
2330                 }
2331                 break;
2332
2333 #ifdef CONFIG_TCP_MD5SIG
2334         case TCP_MD5SIG:
2335                 /* Read the IP->Key mappings from userspace */
2336                 err = tp->af_specific->md5_parse(sk, optval, optlen);
2337                 break;
2338 #endif
2339
2340         default:
2341                 err = -ENOPROTOOPT;
2342                 break;
2343         }
2344
2345         release_sock(sk);
2346         return err;
2347 }
2348
2349 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2350                    unsigned int optlen)
2351 {
2352         struct inet_connection_sock *icsk = inet_csk(sk);
2353
2354         if (level != SOL_TCP)
2355                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2356                                                      optval, optlen);
2357         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2358 }
2359
2360 #ifdef CONFIG_COMPAT
2361 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2362                           char __user *optval, unsigned int optlen)
2363 {
2364         if (level != SOL_TCP)
2365                 return inet_csk_compat_setsockopt(sk, level, optname,
2366                                                   optval, optlen);
2367         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2368 }
2369
2370 EXPORT_SYMBOL(compat_tcp_setsockopt);
2371 #endif
2372
2373 /* Return information about state of tcp endpoint in API format. */
2374 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2375 {
2376         struct tcp_sock *tp = tcp_sk(sk);
2377         const struct inet_connection_sock *icsk = inet_csk(sk);
2378         u32 now = tcp_time_stamp;
2379
2380         memset(info, 0, sizeof(*info));
2381
2382         info->tcpi_state = sk->sk_state;
2383         info->tcpi_ca_state = icsk->icsk_ca_state;
2384         info->tcpi_retransmits = icsk->icsk_retransmits;
2385         info->tcpi_probes = icsk->icsk_probes_out;
2386         info->tcpi_backoff = icsk->icsk_backoff;
2387
2388         if (tp->rx_opt.tstamp_ok)
2389                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2390         if (tcp_is_sack(tp))
2391                 info->tcpi_options |= TCPI_OPT_SACK;
2392         if (tp->rx_opt.wscale_ok) {
2393                 info->tcpi_options |= TCPI_OPT_WSCALE;
2394                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2395                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2396         }
2397
2398         if (tp->ecn_flags&TCP_ECN_OK)
2399                 info->tcpi_options |= TCPI_OPT_ECN;
2400
2401         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2402         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2403         info->tcpi_snd_mss = tp->mss_cache;
2404         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2405
2406         if (sk->sk_state == TCP_LISTEN) {
2407                 info->tcpi_unacked = sk->sk_ack_backlog;
2408                 info->tcpi_sacked = sk->sk_max_ack_backlog;
2409         } else {
2410                 info->tcpi_unacked = tp->packets_out;
2411                 info->tcpi_sacked = tp->sacked_out;
2412         }
2413         info->tcpi_lost = tp->lost_out;
2414         info->tcpi_retrans = tp->retrans_out;
2415         info->tcpi_fackets = tp->fackets_out;
2416
2417         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2418         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2419         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2420
2421         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2422         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2423         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2424         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2425         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2426         info->tcpi_snd_cwnd = tp->snd_cwnd;
2427         info->tcpi_advmss = tp->advmss;
2428         info->tcpi_reordering = tp->reordering;
2429
2430         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2431         info->tcpi_rcv_space = tp->rcvq_space.space;
2432
2433         info->tcpi_total_retrans = tp->total_retrans;
2434 }
2435
2436 EXPORT_SYMBOL_GPL(tcp_get_info);
2437
2438 static int do_tcp_getsockopt(struct sock *sk, int level,
2439                 int optname, char __user *optval, int __user *optlen)
2440 {
2441         struct inet_connection_sock *icsk = inet_csk(sk);
2442         struct tcp_sock *tp = tcp_sk(sk);
2443         int val, len;
2444
2445         if (get_user(len, optlen))
2446                 return -EFAULT;
2447
2448         len = min_t(unsigned int, len, sizeof(int));
2449
2450         if (len < 0)
2451                 return -EINVAL;
2452
2453         switch (optname) {
2454         case TCP_MAXSEG:
2455                 val = tp->mss_cache;
2456                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2457                         val = tp->rx_opt.user_mss;
2458                 break;
2459         case TCP_NODELAY:
2460                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2461                 break;
2462         case TCP_CORK:
2463                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2464                 break;
2465         case TCP_KEEPIDLE:
2466                 val = keepalive_time_when(tp) / HZ;
2467                 break;
2468         case TCP_KEEPINTVL:
2469                 val = keepalive_intvl_when(tp) / HZ;
2470                 break;
2471         case TCP_KEEPCNT:
2472                 val = keepalive_probes(tp);
2473                 break;
2474         case TCP_SYNCNT:
2475                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2476                 break;
2477         case TCP_LINGER2:
2478                 val = tp->linger2;
2479                 if (val >= 0)
2480                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2481                 break;
2482         case TCP_DEFER_ACCEPT:
2483                 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2484                                       TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2485                 break;
2486         case TCP_WINDOW_CLAMP:
2487                 val = tp->window_clamp;
2488                 break;
2489         case TCP_INFO: {
2490                 struct tcp_info info;
2491
2492                 if (get_user(len, optlen))
2493                         return -EFAULT;
2494
2495                 tcp_get_info(sk, &info);
2496
2497                 len = min_t(unsigned int, len, sizeof(info));
2498                 if (put_user(len, optlen))
2499                         return -EFAULT;
2500                 if (copy_to_user(optval, &info, len))
2501                         return -EFAULT;
2502                 return 0;
2503         }
2504         case TCP_QUICKACK:
2505                 val = !icsk->icsk_ack.pingpong;
2506                 break;
2507
2508         case TCP_CONGESTION:
2509                 if (get_user(len, optlen))
2510                         return -EFAULT;
2511                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2512                 if (put_user(len, optlen))
2513                         return -EFAULT;
2514                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2515                         return -EFAULT;
2516                 return 0;
2517
2518         case TCP_COOKIE_TRANSACTIONS: {
2519                 struct tcp_cookie_transactions ctd;
2520                 struct tcp_cookie_values *cvp = tp->cookie_values;
2521
2522                 if (get_user(len, optlen))
2523                         return -EFAULT;
2524                 if (len < sizeof(ctd))
2525                         return -EINVAL;
2526
2527                 memset(&ctd, 0, sizeof(ctd));
2528                 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2529                                    TCP_COOKIE_IN_ALWAYS : 0)
2530                                 | (tp->rx_opt.cookie_out_never ?
2531                                    TCP_COOKIE_OUT_NEVER : 0);
2532
2533                 if (cvp != NULL) {
2534                         ctd.tcpct_flags |= (cvp->s_data_in ?
2535                                             TCP_S_DATA_IN : 0)
2536                                          | (cvp->s_data_out ?
2537                                             TCP_S_DATA_OUT : 0);
2538
2539                         ctd.tcpct_cookie_desired = cvp->cookie_desired;
2540                         ctd.tcpct_s_data_desired = cvp->s_data_desired;
2541
2542                         memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2543                                cvp->cookie_pair_size);
2544                         ctd.tcpct_used = cvp->cookie_pair_size;
2545                 }
2546
2547                 if (put_user(sizeof(ctd), optlen))
2548                         return -EFAULT;
2549                 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2550                         return -EFAULT;
2551                 return 0;
2552         }
2553         default:
2554                 return -ENOPROTOOPT;
2555         }
2556
2557         if (put_user(len, optlen))
2558                 return -EFAULT;
2559         if (copy_to_user(optval, &val, len))
2560                 return -EFAULT;
2561         return 0;
2562 }
2563
2564 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2565                    int __user *optlen)
2566 {
2567         struct inet_connection_sock *icsk = inet_csk(sk);
2568
2569         if (level != SOL_TCP)
2570                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2571                                                      optval, optlen);
2572         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2573 }
2574
2575 #ifdef CONFIG_COMPAT
2576 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2577                           char __user *optval, int __user *optlen)
2578 {
2579         if (level != SOL_TCP)
2580                 return inet_csk_compat_getsockopt(sk, level, optname,
2581                                                   optval, optlen);
2582         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2583 }
2584
2585 EXPORT_SYMBOL(compat_tcp_getsockopt);
2586 #endif
2587
2588 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2589 {
2590         struct sk_buff *segs = ERR_PTR(-EINVAL);
2591         struct tcphdr *th;
2592         unsigned thlen;
2593         unsigned int seq;
2594         __be32 delta;
2595         unsigned int oldlen;
2596         unsigned int mss;
2597
2598         if (!pskb_may_pull(skb, sizeof(*th)))
2599                 goto out;
2600
2601         th = tcp_hdr(skb);
2602         thlen = th->doff * 4;
2603         if (thlen < sizeof(*th))
2604                 goto out;
2605
2606         if (!pskb_may_pull(skb, thlen))
2607                 goto out;
2608
2609         oldlen = (u16)~skb->len;
2610         __skb_pull(skb, thlen);
2611
2612         mss = skb_shinfo(skb)->gso_size;
2613         if (unlikely(skb->len <= mss))
2614                 goto out;
2615
2616         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2617                 /* Packet is from an untrusted source, reset gso_segs. */
2618                 int type = skb_shinfo(skb)->gso_type;
2619
2620                 if (unlikely(type &
2621                              ~(SKB_GSO_TCPV4 |
2622                                SKB_GSO_DODGY |
2623                                SKB_GSO_TCP_ECN |
2624                                SKB_GSO_TCPV6 |
2625                                0) ||
2626                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2627                         goto out;
2628
2629                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2630
2631                 segs = NULL;
2632                 goto out;
2633         }
2634
2635         segs = skb_segment(skb, features);
2636         if (IS_ERR(segs))
2637                 goto out;
2638
2639         delta = htonl(oldlen + (thlen + mss));
2640
2641         skb = segs;
2642         th = tcp_hdr(skb);
2643         seq = ntohl(th->seq);
2644
2645         do {
2646                 th->fin = th->psh = 0;
2647
2648                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2649                                        (__force u32)delta));
2650                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2651                         th->check =
2652                              csum_fold(csum_partial(skb_transport_header(skb),
2653                                                     thlen, skb->csum));
2654
2655                 seq += mss;
2656                 skb = skb->next;
2657                 th = tcp_hdr(skb);
2658
2659                 th->seq = htonl(seq);
2660                 th->cwr = 0;
2661         } while (skb->next);
2662
2663         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2664                       skb->data_len);
2665         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2666                                 (__force u32)delta));
2667         if (skb->ip_summed != CHECKSUM_PARTIAL)
2668                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2669                                                    thlen, skb->csum));
2670
2671 out:
2672         return segs;
2673 }
2674 EXPORT_SYMBOL(tcp_tso_segment);
2675
2676 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2677 {
2678         struct sk_buff **pp = NULL;
2679         struct sk_buff *p;
2680         struct tcphdr *th;
2681         struct tcphdr *th2;
2682         unsigned int len;
2683         unsigned int thlen;
2684         unsigned int flags;
2685         unsigned int mss = 1;
2686         unsigned int hlen;
2687         unsigned int off;
2688         int flush = 1;
2689         int i;
2690
2691         off = skb_gro_offset(skb);
2692         hlen = off + sizeof(*th);
2693         th = skb_gro_header_fast(skb, off);
2694         if (skb_gro_header_hard(skb, hlen)) {
2695                 th = skb_gro_header_slow(skb, hlen, off);
2696                 if (unlikely(!th))
2697                         goto out;
2698         }
2699
2700         thlen = th->doff * 4;
2701         if (thlen < sizeof(*th))
2702                 goto out;
2703
2704         hlen = off + thlen;
2705         if (skb_gro_header_hard(skb, hlen)) {
2706                 th = skb_gro_header_slow(skb, hlen, off);
2707                 if (unlikely(!th))
2708                         goto out;
2709         }
2710
2711         skb_gro_pull(skb, thlen);
2712
2713         len = skb_gro_len(skb);
2714         flags = tcp_flag_word(th);
2715
2716         for (; (p = *head); head = &p->next) {
2717                 if (!NAPI_GRO_CB(p)->same_flow)
2718                         continue;
2719
2720                 th2 = tcp_hdr(p);
2721
2722                 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2723                         NAPI_GRO_CB(p)->same_flow = 0;
2724                         continue;
2725                 }
2726
2727                 goto found;
2728         }
2729
2730         goto out_check_final;
2731
2732 found:
2733         flush = NAPI_GRO_CB(p)->flush;
2734         flush |= flags & TCP_FLAG_CWR;
2735         flush |= (flags ^ tcp_flag_word(th2)) &
2736                   ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2737         flush |= th->ack_seq ^ th2->ack_seq;
2738         for (i = sizeof(*th); i < thlen; i += 4)
2739                 flush |= *(u32 *)((u8 *)th + i) ^
2740                          *(u32 *)((u8 *)th2 + i);
2741
2742         mss = skb_shinfo(p)->gso_size;
2743
2744         flush |= (len - 1) >= mss;
2745         flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2746
2747         if (flush || skb_gro_receive(head, skb)) {
2748                 mss = 1;
2749                 goto out_check_final;
2750         }
2751
2752         p = *head;
2753         th2 = tcp_hdr(p);
2754         tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2755
2756 out_check_final:
2757         flush = len < mss;
2758         flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2759                           TCP_FLAG_SYN | TCP_FLAG_FIN);
2760
2761         if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2762                 pp = head;
2763
2764 out:
2765         NAPI_GRO_CB(skb)->flush |= flush;
2766
2767         return pp;
2768 }
2769 EXPORT_SYMBOL(tcp_gro_receive);
2770
2771 int tcp_gro_complete(struct sk_buff *skb)
2772 {
2773         struct tcphdr *th = tcp_hdr(skb);
2774
2775         skb->csum_start = skb_transport_header(skb) - skb->head;
2776         skb->csum_offset = offsetof(struct tcphdr, check);
2777         skb->ip_summed = CHECKSUM_PARTIAL;
2778
2779         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2780
2781         if (th->cwr)
2782                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2783
2784         return 0;
2785 }
2786 EXPORT_SYMBOL(tcp_gro_complete);
2787
2788 #ifdef CONFIG_TCP_MD5SIG
2789 static unsigned long tcp_md5sig_users;
2790 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2791 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2792
2793 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2794 {
2795         int cpu;
2796         for_each_possible_cpu(cpu) {
2797                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2798                 if (p) {
2799                         if (p->md5_desc.tfm)
2800                                 crypto_free_hash(p->md5_desc.tfm);
2801                         kfree(p);
2802                         p = NULL;
2803                 }
2804         }
2805         free_percpu(pool);
2806 }
2807
2808 void tcp_free_md5sig_pool(void)
2809 {
2810         struct tcp_md5sig_pool **pool = NULL;
2811
2812         spin_lock_bh(&tcp_md5sig_pool_lock);
2813         if (--tcp_md5sig_users == 0) {
2814                 pool = tcp_md5sig_pool;
2815                 tcp_md5sig_pool = NULL;
2816         }
2817         spin_unlock_bh(&tcp_md5sig_pool_lock);
2818         if (pool)
2819                 __tcp_free_md5sig_pool(pool);
2820 }
2821
2822 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2823
2824 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(struct sock *sk)
2825 {
2826         int cpu;
2827         struct tcp_md5sig_pool **pool;
2828
2829         pool = alloc_percpu(struct tcp_md5sig_pool *);
2830         if (!pool)
2831                 return NULL;
2832
2833         for_each_possible_cpu(cpu) {
2834                 struct tcp_md5sig_pool *p;
2835                 struct crypto_hash *hash;
2836
2837                 p = kzalloc(sizeof(*p), sk->sk_allocation);
2838                 if (!p)
2839                         goto out_free;
2840                 *per_cpu_ptr(pool, cpu) = p;
2841
2842                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2843                 if (!hash || IS_ERR(hash))
2844                         goto out_free;
2845
2846                 p->md5_desc.tfm = hash;
2847         }
2848         return pool;
2849 out_free:
2850         __tcp_free_md5sig_pool(pool);
2851         return NULL;
2852 }
2853
2854 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *sk)
2855 {
2856         struct tcp_md5sig_pool **pool;
2857         int alloc = 0;
2858
2859 retry:
2860         spin_lock_bh(&tcp_md5sig_pool_lock);
2861         pool = tcp_md5sig_pool;
2862         if (tcp_md5sig_users++ == 0) {
2863                 alloc = 1;
2864                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2865         } else if (!pool) {
2866                 tcp_md5sig_users--;
2867                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2868                 cpu_relax();
2869                 goto retry;
2870         } else
2871                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2872
2873         if (alloc) {
2874                 /* we cannot hold spinlock here because this may sleep. */
2875                 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(sk);
2876                 spin_lock_bh(&tcp_md5sig_pool_lock);
2877                 if (!p) {
2878                         tcp_md5sig_users--;
2879                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2880                         return NULL;
2881                 }
2882                 pool = tcp_md5sig_pool;
2883                 if (pool) {
2884                         /* oops, it has already been assigned. */
2885                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2886                         __tcp_free_md5sig_pool(p);
2887                 } else {
2888                         tcp_md5sig_pool = pool = p;
2889                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2890                 }
2891         }
2892         return pool;
2893 }
2894
2895 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2896
2897 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2898 {
2899         struct tcp_md5sig_pool **p;
2900         spin_lock_bh(&tcp_md5sig_pool_lock);
2901         p = tcp_md5sig_pool;
2902         if (p)
2903                 tcp_md5sig_users++;
2904         spin_unlock_bh(&tcp_md5sig_pool_lock);
2905         return (p ? *per_cpu_ptr(p, cpu) : NULL);
2906 }
2907
2908 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2909
2910 void __tcp_put_md5sig_pool(void)
2911 {
2912         tcp_free_md5sig_pool();
2913 }
2914
2915 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2916
2917 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2918                         struct tcphdr *th)
2919 {
2920         struct scatterlist sg;
2921         int err;
2922
2923         __sum16 old_checksum = th->check;
2924         th->check = 0;
2925         /* options aren't included in the hash */
2926         sg_init_one(&sg, th, sizeof(struct tcphdr));
2927         err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2928         th->check = old_checksum;
2929         return err;
2930 }
2931
2932 EXPORT_SYMBOL(tcp_md5_hash_header);
2933
2934 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2935                           struct sk_buff *skb, unsigned header_len)
2936 {
2937         struct scatterlist sg;
2938         const struct tcphdr *tp = tcp_hdr(skb);
2939         struct hash_desc *desc = &hp->md5_desc;
2940         unsigned i;
2941         const unsigned head_data_len = skb_headlen(skb) > header_len ?
2942                                        skb_headlen(skb) - header_len : 0;
2943         const struct skb_shared_info *shi = skb_shinfo(skb);
2944
2945         sg_init_table(&sg, 1);
2946
2947         sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2948         if (crypto_hash_update(desc, &sg, head_data_len))
2949                 return 1;
2950
2951         for (i = 0; i < shi->nr_frags; ++i) {
2952                 const struct skb_frag_struct *f = &shi->frags[i];
2953                 sg_set_page(&sg, f->page, f->size, f->page_offset);
2954                 if (crypto_hash_update(desc, &sg, f->size))
2955                         return 1;
2956         }
2957
2958         return 0;
2959 }
2960
2961 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2962
2963 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
2964 {
2965         struct scatterlist sg;
2966
2967         sg_init_one(&sg, key->key, key->keylen);
2968         return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2969 }
2970
2971 EXPORT_SYMBOL(tcp_md5_hash_key);
2972
2973 #endif
2974
2975 /**
2976  * Each Responder maintains up to two secret values concurrently for
2977  * efficient secret rollover.  Each secret value has 4 states:
2978  *
2979  * Generating.  (tcp_secret_generating != tcp_secret_primary)
2980  *    Generates new Responder-Cookies, but not yet used for primary
2981  *    verification.  This is a short-term state, typically lasting only
2982  *    one round trip time (RTT).
2983  *
2984  * Primary.  (tcp_secret_generating == tcp_secret_primary)
2985  *    Used both for generation and primary verification.
2986  *
2987  * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
2988  *    Used for verification, until the first failure that can be
2989  *    verified by the newer Generating secret.  At that time, this
2990  *    cookie's state is changed to Secondary, and the Generating
2991  *    cookie's state is changed to Primary.  This is a short-term state,
2992  *    typically lasting only one round trip time (RTT).
2993  *
2994  * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
2995  *    Used for secondary verification, after primary verification
2996  *    failures.  This state lasts no more than twice the Maximum Segment
2997  *    Lifetime (2MSL).  Then, the secret is discarded.
2998  */
2999 struct tcp_cookie_secret {
3000         /* The secret is divided into two parts.  The digest part is the
3001          * equivalent of previously hashing a secret and saving the state,
3002          * and serves as an initialization vector (IV).  The message part
3003          * serves as the trailing secret.
3004          */
3005         u32                             secrets[COOKIE_WORKSPACE_WORDS];
3006         unsigned long                   expires;
3007 };
3008
3009 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3010 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3011 #define TCP_SECRET_LIFE (HZ * 600)
3012
3013 static struct tcp_cookie_secret tcp_secret_one;
3014 static struct tcp_cookie_secret tcp_secret_two;
3015
3016 /* Essentially a circular list, without dynamic allocation. */
3017 static struct tcp_cookie_secret *tcp_secret_generating;
3018 static struct tcp_cookie_secret *tcp_secret_primary;
3019 static struct tcp_cookie_secret *tcp_secret_retiring;
3020 static struct tcp_cookie_secret *tcp_secret_secondary;
3021
3022 static DEFINE_SPINLOCK(tcp_secret_locker);
3023
3024 /* Select a pseudo-random word in the cookie workspace.
3025  */
3026 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3027 {
3028         return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3029 }
3030
3031 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3032  * Called in softirq context.
3033  * Returns: 0 for success.
3034  */
3035 int tcp_cookie_generator(u32 *bakery)
3036 {
3037         unsigned long jiffy = jiffies;
3038
3039         if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3040                 spin_lock_bh(&tcp_secret_locker);
3041                 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3042                         /* refreshed by another */
3043                         memcpy(bakery,
3044                                &tcp_secret_generating->secrets[0],
3045                                COOKIE_WORKSPACE_WORDS);
3046                 } else {
3047                         /* still needs refreshing */
3048                         get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3049
3050                         /* The first time, paranoia assumes that the
3051                          * randomization function isn't as strong.  But,
3052                          * this secret initialization is delayed until
3053                          * the last possible moment (packet arrival).
3054                          * Although that time is observable, it is
3055                          * unpredictably variable.  Mash in the most
3056                          * volatile clock bits available, and expire the
3057                          * secret extra quickly.
3058                          */
3059                         if (unlikely(tcp_secret_primary->expires ==
3060                                      tcp_secret_secondary->expires)) {
3061                                 struct timespec tv;
3062
3063                                 getnstimeofday(&tv);
3064                                 bakery[COOKIE_DIGEST_WORDS+0] ^=
3065                                         (u32)tv.tv_nsec;
3066
3067                                 tcp_secret_secondary->expires = jiffy
3068                                         + TCP_SECRET_1MSL
3069                                         + (0x0f & tcp_cookie_work(bakery, 0));
3070                         } else {
3071                                 tcp_secret_secondary->expires = jiffy
3072                                         + TCP_SECRET_LIFE
3073                                         + (0xff & tcp_cookie_work(bakery, 1));
3074                                 tcp_secret_primary->expires = jiffy
3075                                         + TCP_SECRET_2MSL
3076                                         + (0x1f & tcp_cookie_work(bakery, 2));
3077                         }
3078                         memcpy(&tcp_secret_secondary->secrets[0],
3079                                bakery, COOKIE_WORKSPACE_WORDS);
3080
3081                         rcu_assign_pointer(tcp_secret_generating,
3082                                            tcp_secret_secondary);
3083                         rcu_assign_pointer(tcp_secret_retiring,
3084                                            tcp_secret_primary);
3085                         /*
3086                          * Neither call_rcu() nor synchronize_rcu() needed.
3087                          * Retiring data is not freed.  It is replaced after
3088                          * further (locked) pointer updates, and a quiet time
3089                          * (minimum 1MSL, maximum LIFE - 2MSL).
3090                          */
3091                 }
3092                 spin_unlock_bh(&tcp_secret_locker);
3093         } else {
3094                 rcu_read_lock_bh();
3095                 memcpy(bakery,
3096                        &rcu_dereference(tcp_secret_generating)->secrets[0],
3097                        COOKIE_WORKSPACE_WORDS);
3098                 rcu_read_unlock_bh();
3099         }
3100         return 0;
3101 }
3102 EXPORT_SYMBOL(tcp_cookie_generator);
3103
3104 void tcp_done(struct sock *sk)
3105 {
3106         if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3107                 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3108
3109         tcp_set_state(sk, TCP_CLOSE);
3110         tcp_clear_xmit_timers(sk);
3111
3112         sk->sk_shutdown = SHUTDOWN_MASK;
3113
3114         if (!sock_flag(sk, SOCK_DEAD))
3115                 sk->sk_state_change(sk);
3116         else
3117                 inet_csk_destroy_sock(sk);
3118 }
3119 EXPORT_SYMBOL_GPL(tcp_done);
3120
3121 extern struct tcp_congestion_ops tcp_reno;
3122
3123 static __initdata unsigned long thash_entries;
3124 static int __init set_thash_entries(char *str)
3125 {
3126         if (!str)
3127                 return 0;
3128         thash_entries = simple_strtoul(str, &str, 0);
3129         return 1;
3130 }
3131 __setup("thash_entries=", set_thash_entries);
3132
3133 void __init tcp_init(void)
3134 {
3135         struct sk_buff *skb = NULL;
3136         unsigned long nr_pages, limit;
3137         int order, i, max_share;
3138         unsigned long jiffy = jiffies;
3139
3140         BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3141
3142         percpu_counter_init(&tcp_sockets_allocated, 0);
3143         percpu_counter_init(&tcp_orphan_count, 0);
3144         tcp_hashinfo.bind_bucket_cachep =
3145                 kmem_cache_create("tcp_bind_bucket",
3146                                   sizeof(struct inet_bind_bucket), 0,
3147                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3148
3149         /* Size and allocate the main established and bind bucket
3150          * hash tables.
3151          *
3152          * The methodology is similar to that of the buffer cache.
3153          */
3154         tcp_hashinfo.ehash =
3155                 alloc_large_system_hash("TCP established",
3156                                         sizeof(struct inet_ehash_bucket),
3157                                         thash_entries,
3158                                         (totalram_pages >= 128 * 1024) ?
3159                                         13 : 15,
3160                                         0,
3161                                         NULL,
3162                                         &tcp_hashinfo.ehash_mask,
3163                                         thash_entries ? 0 : 512 * 1024);
3164         for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3165                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3166                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3167         }
3168         if (inet_ehash_locks_alloc(&tcp_hashinfo))
3169                 panic("TCP: failed to alloc ehash_locks");
3170         tcp_hashinfo.bhash =
3171                 alloc_large_system_hash("TCP bind",
3172                                         sizeof(struct inet_bind_hashbucket),
3173                                         tcp_hashinfo.ehash_mask + 1,
3174                                         (totalram_pages >= 128 * 1024) ?
3175                                         13 : 15,
3176                                         0,
3177                                         &tcp_hashinfo.bhash_size,
3178                                         NULL,
3179                                         64 * 1024);
3180         tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3181         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3182                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3183                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3184         }
3185
3186         /* Try to be a bit smarter and adjust defaults depending
3187          * on available memory.
3188          */
3189         for (order = 0; ((1 << order) << PAGE_SHIFT) <
3190                         (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
3191                         order++)
3192                 ;
3193         if (order >= 4) {
3194                 tcp_death_row.sysctl_max_tw_buckets = 180000;
3195                 sysctl_tcp_max_orphans = 4096 << (order - 4);
3196                 sysctl_max_syn_backlog = 1024;
3197         } else if (order < 3) {
3198                 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
3199                 sysctl_tcp_max_orphans >>= (3 - order);
3200                 sysctl_max_syn_backlog = 128;
3201         }
3202
3203         /* Set the pressure threshold to be a fraction of global memory that
3204          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3205          * memory, with a floor of 128 pages.
3206          */
3207         nr_pages = totalram_pages - totalhigh_pages;
3208         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3209         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3210         limit = max(limit, 128UL);
3211         sysctl_tcp_mem[0] = limit / 4 * 3;
3212         sysctl_tcp_mem[1] = limit;
3213         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3214
3215         /* Set per-socket limits to no more than 1/128 the pressure threshold */
3216         limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3217         max_share = min(4UL*1024*1024, limit);
3218
3219         sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3220         sysctl_tcp_wmem[1] = 16*1024;
3221         sysctl_tcp_wmem[2] = max(64*1024, max_share);
3222
3223         sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3224         sysctl_tcp_rmem[1] = 87380;
3225         sysctl_tcp_rmem[2] = max(87380, max_share);
3226
3227         printk(KERN_INFO "TCP: Hash tables configured "
3228                "(established %u bind %u)\n",
3229                tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3230
3231         tcp_register_congestion_control(&tcp_reno);
3232
3233         memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3234         memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3235         tcp_secret_one.expires = jiffy; /* past due */
3236         tcp_secret_two.expires = jiffy; /* past due */
3237         tcp_secret_generating = &tcp_secret_one;
3238         tcp_secret_primary = &tcp_secret_one;
3239         tcp_secret_retiring = &tcp_secret_two;
3240         tcp_secret_secondary = &tcp_secret_two;
3241 }
3242
3243 EXPORT_SYMBOL(tcp_close);
3244 EXPORT_SYMBOL(tcp_disconnect);
3245 EXPORT_SYMBOL(tcp_getsockopt);
3246 EXPORT_SYMBOL(tcp_ioctl);
3247 EXPORT_SYMBOL(tcp_poll);
3248 EXPORT_SYMBOL(tcp_read_sock);
3249 EXPORT_SYMBOL(tcp_recvmsg);
3250 EXPORT_SYMBOL(tcp_sendmsg);
3251 EXPORT_SYMBOL(tcp_splice_read);
3252 EXPORT_SYMBOL(tcp_sendpage);
3253 EXPORT_SYMBOL(tcp_setsockopt);
3254 EXPORT_SYMBOL(tcp_shutdown);