tcp: avoid infinite loop in tcp_splice_read()
[pandora-kernel.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 #include <linux/slab.h>
269
270 #include <net/icmp.h>
271 #include <net/tcp.h>
272 #include <net/xfrm.h>
273 #include <net/ip.h>
274 #include <net/netdma.h>
275 #include <net/sock.h>
276
277 #include <asm/uaccess.h>
278 #include <asm/ioctls.h>
279
280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281
282 struct percpu_counter tcp_orphan_count;
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285 long sysctl_tcp_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
288
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
292
293 atomic_long_t tcp_memory_allocated;     /* Current allocated memory. */
294 EXPORT_SYMBOL(tcp_memory_allocated);
295
296 /*
297  * Current number of TCP sockets.
298  */
299 struct percpu_counter tcp_sockets_allocated;
300 EXPORT_SYMBOL(tcp_sockets_allocated);
301
302 /*
303  * TCP splice context
304  */
305 struct tcp_splice_state {
306         struct pipe_inode_info *pipe;
307         size_t len;
308         unsigned int flags;
309 };
310
311 /*
312  * Pressure flag: try to collapse.
313  * Technical note: it is used by multiple contexts non atomically.
314  * All the __sk_mem_schedule() is of this nature: accounting
315  * is strict, actions are advisory and have some latency.
316  */
317 int tcp_memory_pressure __read_mostly;
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 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329 /* Convert seconds to retransmits based on initial and max timeout */
330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331 {
332         u8 res = 0;
333
334         if (seconds > 0) {
335                 int period = timeout;
336
337                 res = 1;
338                 while (seconds > period && res < 255) {
339                         res++;
340                         timeout <<= 1;
341                         if (timeout > rto_max)
342                                 timeout = rto_max;
343                         period += timeout;
344                 }
345         }
346         return res;
347 }
348
349 /* Convert retransmits to seconds based on initial and max timeout */
350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351 {
352         int period = 0;
353
354         if (retrans > 0) {
355                 period = timeout;
356                 while (--retrans) {
357                         timeout <<= 1;
358                         if (timeout > rto_max)
359                                 timeout = rto_max;
360                         period += timeout;
361                 }
362         }
363         return period;
364 }
365
366 /*
367  *      Wait for a TCP event.
368  *
369  *      Note that we don't need to lock the socket, as the upper poll layers
370  *      take care of normal races (between the test and the event) and we don't
371  *      go look at any of the socket buffers directly.
372  */
373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374 {
375         unsigned int mask;
376         struct sock *sk = sock->sk;
377         const struct tcp_sock *tp = tcp_sk(sk);
378
379         sock_poll_wait(file, sk_sleep(sk), wait);
380         if (sk->sk_state == TCP_LISTEN)
381                 return inet_csk_listen_poll(sk);
382
383         /* Socket is not locked. We are protected from async events
384          * by poll logic and correct handling of state changes
385          * made by other threads is impossible in any case.
386          */
387
388         mask = 0;
389
390         /*
391          * POLLHUP is certainly not done right. But poll() doesn't
392          * have a notion of HUP in just one direction, and for a
393          * socket the read side is more interesting.
394          *
395          * Some poll() documentation says that POLLHUP is incompatible
396          * with the POLLOUT/POLLWR flags, so somebody should check this
397          * all. But careful, it tends to be safer to return too many
398          * bits than too few, and you can easily break real applications
399          * if you don't tell them that something has hung up!
400          *
401          * Check-me.
402          *
403          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
404          * our fs/select.c). It means that after we received EOF,
405          * poll always returns immediately, making impossible poll() on write()
406          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
407          * if and only if shutdown has been made in both directions.
408          * Actually, it is interesting to look how Solaris and DUX
409          * solve this dilemma. I would prefer, if POLLHUP were maskable,
410          * then we could set it on SND_SHUTDOWN. BTW examples given
411          * in Stevens' books assume exactly this behaviour, it explains
412          * why POLLHUP is incompatible with POLLOUT.    --ANK
413          *
414          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
415          * blocking on fresh not-connected or disconnected socket. --ANK
416          */
417         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
418                 mask |= POLLHUP;
419         if (sk->sk_shutdown & RCV_SHUTDOWN)
420                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
421
422         /* Connected? */
423         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
424                 int target = sock_rcvlowat(sk, 0, INT_MAX);
425
426                 if (tp->urg_seq == tp->copied_seq &&
427                     !sock_flag(sk, SOCK_URGINLINE) &&
428                     tp->urg_data)
429                         target++;
430
431                 /* Potential race condition. If read of tp below will
432                  * escape above sk->sk_state, we can be illegally awaken
433                  * in SYN_* states. */
434                 if (tp->rcv_nxt - tp->copied_seq >= target)
435                         mask |= POLLIN | POLLRDNORM;
436
437                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
438                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
439                                 mask |= POLLOUT | POLLWRNORM;
440                         } else {  /* send SIGIO later */
441                                 set_bit(SOCK_ASYNC_NOSPACE,
442                                         &sk->sk_socket->flags);
443                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
444
445                                 /* Race breaker. If space is freed after
446                                  * wspace test but before the flags are set,
447                                  * IO signal will be lost.
448                                  */
449                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
450                                         mask |= POLLOUT | POLLWRNORM;
451                         }
452                 } else
453                         mask |= POLLOUT | POLLWRNORM;
454
455                 if (tp->urg_data & TCP_URG_VALID)
456                         mask |= POLLPRI;
457         }
458         /* This barrier is coupled with smp_wmb() in tcp_reset() */
459         smp_rmb();
460         if (sk->sk_err)
461                 mask |= POLLERR;
462
463         return mask;
464 }
465 EXPORT_SYMBOL(tcp_poll);
466
467 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
468 {
469         struct tcp_sock *tp = tcp_sk(sk);
470         int answ;
471
472         switch (cmd) {
473         case SIOCINQ:
474                 if (sk->sk_state == TCP_LISTEN)
475                         return -EINVAL;
476
477                 lock_sock(sk);
478                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
479                         answ = 0;
480                 else if (sock_flag(sk, SOCK_URGINLINE) ||
481                          !tp->urg_data ||
482                          before(tp->urg_seq, tp->copied_seq) ||
483                          !before(tp->urg_seq, tp->rcv_nxt)) {
484
485                         answ = tp->rcv_nxt - tp->copied_seq;
486
487                         /* Subtract 1, if FIN was received */
488                         if (answ && sock_flag(sk, SOCK_DONE))
489                                 answ--;
490                 } else
491                         answ = tp->urg_seq - tp->copied_seq;
492                 release_sock(sk);
493                 break;
494         case SIOCATMARK:
495                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
496                 break;
497         case SIOCOUTQ:
498                 if (sk->sk_state == TCP_LISTEN)
499                         return -EINVAL;
500
501                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
502                         answ = 0;
503                 else
504                         answ = tp->write_seq - tp->snd_una;
505                 break;
506         case SIOCOUTQNSD:
507                 if (sk->sk_state == TCP_LISTEN)
508                         return -EINVAL;
509
510                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
511                         answ = 0;
512                 else
513                         answ = tp->write_seq - tp->snd_nxt;
514                 break;
515         default:
516                 return -ENOIOCTLCMD;
517         }
518
519         return put_user(answ, (int __user *)arg);
520 }
521 EXPORT_SYMBOL(tcp_ioctl);
522
523 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
524 {
525         TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
526         tp->pushed_seq = tp->write_seq;
527 }
528
529 static inline int forced_push(const struct tcp_sock *tp)
530 {
531         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
532 }
533
534 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
535 {
536         struct tcp_sock *tp = tcp_sk(sk);
537         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
538
539         skb->csum    = 0;
540         tcb->seq     = tcb->end_seq = tp->write_seq;
541         tcb->tcp_flags = TCPHDR_ACK;
542         tcb->sacked  = 0;
543         skb_header_release(skb);
544         tcp_add_write_queue_tail(sk, skb);
545         sk->sk_wmem_queued += skb->truesize;
546         sk_mem_charge(sk, skb->truesize);
547         if (tp->nonagle & TCP_NAGLE_PUSH)
548                 tp->nonagle &= ~TCP_NAGLE_PUSH;
549 }
550
551 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
552 {
553         if (flags & MSG_OOB)
554                 tp->snd_up = tp->write_seq;
555 }
556
557 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
558                             int nonagle)
559 {
560         if (tcp_send_head(sk)) {
561                 struct tcp_sock *tp = tcp_sk(sk);
562
563                 if (!(flags & MSG_MORE) || forced_push(tp))
564                         tcp_mark_push(tp, tcp_write_queue_tail(sk));
565
566                 tcp_mark_urg(tp, flags);
567                 __tcp_push_pending_frames(sk, mss_now,
568                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
569         }
570 }
571
572 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
573                                 unsigned int offset, size_t len)
574 {
575         struct tcp_splice_state *tss = rd_desc->arg.data;
576         int ret;
577
578         ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
579                               tss->flags);
580         if (ret > 0)
581                 rd_desc->count -= ret;
582         return ret;
583 }
584
585 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
586 {
587         /* Store TCP splice context information in read_descriptor_t. */
588         read_descriptor_t rd_desc = {
589                 .arg.data = tss,
590                 .count    = tss->len,
591         };
592
593         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
594 }
595
596 /**
597  *  tcp_splice_read - splice data from TCP socket to a pipe
598  * @sock:       socket to splice from
599  * @ppos:       position (not valid)
600  * @pipe:       pipe to splice to
601  * @len:        number of bytes to splice
602  * @flags:      splice modifier flags
603  *
604  * Description:
605  *    Will read pages from given socket and fill them into a pipe.
606  *
607  **/
608 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
609                         struct pipe_inode_info *pipe, size_t len,
610                         unsigned int flags)
611 {
612         struct sock *sk = sock->sk;
613         struct tcp_splice_state tss = {
614                 .pipe = pipe,
615                 .len = len,
616                 .flags = flags,
617         };
618         long timeo;
619         ssize_t spliced;
620         int ret;
621
622         sock_rps_record_flow(sk);
623         /*
624          * We can't seek on a socket input
625          */
626         if (unlikely(*ppos))
627                 return -ESPIPE;
628
629         ret = spliced = 0;
630
631         lock_sock(sk);
632
633         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
634         while (tss.len) {
635                 ret = __tcp_splice_read(sk, &tss);
636                 if (ret < 0)
637                         break;
638                 else if (!ret) {
639                         if (spliced)
640                                 break;
641                         if (sock_flag(sk, SOCK_DONE))
642                                 break;
643                         if (sk->sk_err) {
644                                 ret = sock_error(sk);
645                                 break;
646                         }
647                         if (sk->sk_shutdown & RCV_SHUTDOWN)
648                                 break;
649                         if (sk->sk_state == TCP_CLOSE) {
650                                 /*
651                                  * This occurs when user tries to read
652                                  * from never connected socket.
653                                  */
654                                 if (!sock_flag(sk, SOCK_DONE))
655                                         ret = -ENOTCONN;
656                                 break;
657                         }
658                         if (!timeo) {
659                                 ret = -EAGAIN;
660                                 break;
661                         }
662                         /* if __tcp_splice_read() got nothing while we have
663                          * an skb in receive queue, we do not want to loop.
664                          * This might happen with URG data.
665                          */
666                         if (!skb_queue_empty(&sk->sk_receive_queue))
667                                 break;
668                         sk_wait_data(sk, &timeo);
669                         if (signal_pending(current)) {
670                                 ret = sock_intr_errno(timeo);
671                                 break;
672                         }
673                         continue;
674                 }
675                 tss.len -= ret;
676                 spliced += ret;
677
678                 if (!timeo)
679                         break;
680                 release_sock(sk);
681                 lock_sock(sk);
682
683                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
684                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
685                     signal_pending(current))
686                         break;
687         }
688
689         release_sock(sk);
690
691         if (spliced)
692                 return spliced;
693
694         return ret;
695 }
696 EXPORT_SYMBOL(tcp_splice_read);
697
698 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
699 {
700         struct sk_buff *skb;
701
702         /* The TCP header must be at least 32-bit aligned.  */
703         size = ALIGN(size, 4);
704
705         skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
706         if (skb) {
707                 if (sk_wmem_schedule(sk, skb->truesize)) {
708                         skb_reserve(skb, sk->sk_prot->max_header);
709                         /*
710                          * Make sure that we have exactly size bytes
711                          * available to the caller, no more, no less.
712                          */
713                         skb->reserved_tailroom = skb->end - skb->tail - size;
714                         return skb;
715                 }
716                 __kfree_skb(skb);
717         } else {
718                 sk->sk_prot->enter_memory_pressure(sk);
719                 sk_stream_moderate_sndbuf(sk);
720         }
721         return NULL;
722 }
723
724 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
725                                        int large_allowed)
726 {
727         struct tcp_sock *tp = tcp_sk(sk);
728         u32 xmit_size_goal, old_size_goal;
729
730         xmit_size_goal = mss_now;
731
732         if (large_allowed && sk_can_gso(sk)) {
733                 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
734                                   inet_csk(sk)->icsk_af_ops->net_header_len -
735                                   inet_csk(sk)->icsk_ext_hdr_len -
736                                   tp->tcp_header_len);
737
738                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
739
740                 /* We try hard to avoid divides here */
741                 old_size_goal = tp->xmit_size_goal_segs * mss_now;
742
743                 if (likely(old_size_goal <= xmit_size_goal &&
744                            old_size_goal + mss_now > xmit_size_goal)) {
745                         xmit_size_goal = old_size_goal;
746                 } else {
747                         tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
748                         xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
749                 }
750         }
751
752         return max(xmit_size_goal, mss_now);
753 }
754
755 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
756 {
757         int mss_now;
758
759         mss_now = tcp_current_mss(sk);
760         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
761
762         return mss_now;
763 }
764
765 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
766                          size_t psize, int flags)
767 {
768         struct tcp_sock *tp = tcp_sk(sk);
769         int mss_now, size_goal;
770         int err;
771         ssize_t copied;
772         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
773
774         /* Wait for a connection to finish. */
775         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
776                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
777                         goto out_err;
778
779         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
780
781         mss_now = tcp_send_mss(sk, &size_goal, flags);
782         copied = 0;
783
784         err = -EPIPE;
785         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
786                 goto out_err;
787
788         while (psize > 0) {
789                 struct sk_buff *skb = tcp_write_queue_tail(sk);
790                 struct page *page = pages[poffset / PAGE_SIZE];
791                 int copy, i, can_coalesce;
792                 int offset = poffset % PAGE_SIZE;
793                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
794
795                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
796 new_segment:
797                         if (!sk_stream_memory_free(sk))
798                                 goto wait_for_sndbuf;
799
800                         skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
801                         if (!skb)
802                                 goto wait_for_memory;
803
804                         skb_entail(sk, skb);
805                         copy = size_goal;
806                 }
807
808                 if (copy > size)
809                         copy = size;
810
811                 i = skb_shinfo(skb)->nr_frags;
812                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
813                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
814                         tcp_mark_push(tp, skb);
815                         goto new_segment;
816                 }
817                 if (!sk_wmem_schedule(sk, copy))
818                         goto wait_for_memory;
819
820                 if (can_coalesce) {
821                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
822                 } else {
823                         get_page(page);
824                         skb_fill_page_desc(skb, i, page, offset, copy);
825                 }
826
827                 skb->len += copy;
828                 skb->data_len += copy;
829                 skb->truesize += copy;
830                 sk->sk_wmem_queued += copy;
831                 sk_mem_charge(sk, copy);
832                 skb->ip_summed = CHECKSUM_PARTIAL;
833                 tp->write_seq += copy;
834                 TCP_SKB_CB(skb)->end_seq += copy;
835                 skb_shinfo(skb)->gso_segs = 0;
836
837                 if (!copied)
838                         TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
839
840                 copied += copy;
841                 poffset += copy;
842                 if (!(psize -= copy))
843                         goto out;
844
845                 if (skb->len < size_goal || (flags & MSG_OOB))
846                         continue;
847
848                 if (forced_push(tp)) {
849                         tcp_mark_push(tp, skb);
850                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
851                 } else if (skb == tcp_send_head(sk))
852                         tcp_push_one(sk, mss_now);
853                 continue;
854
855 wait_for_sndbuf:
856                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
857 wait_for_memory:
858                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
859
860                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
861                         goto do_error;
862
863                 mss_now = tcp_send_mss(sk, &size_goal, flags);
864         }
865
866 out:
867         if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
868                 tcp_push(sk, flags, mss_now, tp->nonagle);
869         return copied;
870
871 do_error:
872         if (copied)
873                 goto out;
874 out_err:
875         return sk_stream_error(sk, flags, err);
876 }
877
878 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
879                  size_t size, int flags)
880 {
881         ssize_t res;
882
883         if (!(sk->sk_route_caps & NETIF_F_SG) ||
884             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
885                 return sock_no_sendpage(sk->sk_socket, page, offset, size,
886                                         flags);
887
888         lock_sock(sk);
889         res = do_tcp_sendpages(sk, &page, offset, size, flags);
890         release_sock(sk);
891         return res;
892 }
893 EXPORT_SYMBOL(tcp_sendpage);
894
895 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
896 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
897
898 static inline int select_size(const struct sock *sk, int sg)
899 {
900         const struct tcp_sock *tp = tcp_sk(sk);
901         int tmp = tp->mss_cache;
902
903         if (sg) {
904                 if (sk_can_gso(sk))
905                         tmp = 0;
906                 else {
907                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
908
909                         if (tmp >= pgbreak &&
910                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
911                                 tmp = pgbreak;
912                 }
913         }
914
915         return tmp;
916 }
917
918 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
919                 size_t size)
920 {
921         struct iovec *iov;
922         struct tcp_sock *tp = tcp_sk(sk);
923         struct sk_buff *skb;
924         int iovlen, flags;
925         int mss_now, size_goal;
926         int sg, err, copied;
927         long timeo;
928
929         lock_sock(sk);
930
931         flags = msg->msg_flags;
932         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
933
934         /* Wait for a connection to finish. */
935         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
936                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
937                         goto out_err;
938
939         /* This should be in poll */
940         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
941
942         mss_now = tcp_send_mss(sk, &size_goal, flags);
943
944         /* Ok commence sending. */
945         iovlen = msg->msg_iovlen;
946         iov = msg->msg_iov;
947         copied = 0;
948
949         err = -EPIPE;
950         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
951                 goto out_err;
952
953         sg = sk->sk_route_caps & NETIF_F_SG;
954
955         while (--iovlen >= 0) {
956                 size_t seglen = iov->iov_len;
957                 unsigned char __user *from = iov->iov_base;
958
959                 iov++;
960
961                 while (seglen > 0) {
962                         int copy = 0;
963                         int max = size_goal;
964
965                         skb = tcp_write_queue_tail(sk);
966                         if (tcp_send_head(sk)) {
967                                 if (skb->ip_summed == CHECKSUM_NONE)
968                                         max = mss_now;
969                                 copy = max - skb->len;
970                         }
971
972                         if (copy <= 0) {
973 new_segment:
974                                 /* Allocate new segment. If the interface is SG,
975                                  * allocate skb fitting to single page.
976                                  */
977                                 if (!sk_stream_memory_free(sk))
978                                         goto wait_for_sndbuf;
979
980                                 skb = sk_stream_alloc_skb(sk,
981                                                           select_size(sk, sg),
982                                                           sk->sk_allocation);
983                                 if (!skb)
984                                         goto wait_for_memory;
985
986                                 /*
987                                  * Check whether we can use HW checksum.
988                                  */
989                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
990                                         skb->ip_summed = CHECKSUM_PARTIAL;
991
992                                 skb_entail(sk, skb);
993                                 copy = size_goal;
994                                 max = size_goal;
995                         }
996
997                         /* Try to append data to the end of skb. */
998                         if (copy > seglen)
999                                 copy = seglen;
1000
1001                         /* Where to copy to? */
1002                         if (skb_availroom(skb) > 0) {
1003                                 /* We have some space in skb head. Superb! */
1004                                 copy = min_t(int, copy, skb_availroom(skb));
1005                                 err = skb_add_data_nocache(sk, skb, from, copy);
1006                                 if (err)
1007                                         goto do_fault;
1008                         } else {
1009                                 int merge = 0;
1010                                 int i = skb_shinfo(skb)->nr_frags;
1011                                 struct page *page = TCP_PAGE(sk);
1012                                 int off = TCP_OFF(sk);
1013
1014                                 if (skb_can_coalesce(skb, i, page, off) &&
1015                                     off != PAGE_SIZE) {
1016                                         /* We can extend the last page
1017                                          * fragment. */
1018                                         merge = 1;
1019                                 } else if (i == MAX_SKB_FRAGS || !sg) {
1020                                         /* Need to add new fragment and cannot
1021                                          * do this because interface is non-SG,
1022                                          * or because all the page slots are
1023                                          * busy. */
1024                                         tcp_mark_push(tp, skb);
1025                                         goto new_segment;
1026                                 } else if (page) {
1027                                         if (off == PAGE_SIZE) {
1028                                                 put_page(page);
1029                                                 TCP_PAGE(sk) = page = NULL;
1030                                                 off = 0;
1031                                         }
1032                                 } else
1033                                         off = 0;
1034
1035                                 if (copy > PAGE_SIZE - off)
1036                                         copy = PAGE_SIZE - off;
1037
1038                                 if (!sk_wmem_schedule(sk, copy))
1039                                         goto wait_for_memory;
1040
1041                                 if (!page) {
1042                                         /* Allocate new cache page. */
1043                                         if (!(page = sk_stream_alloc_page(sk)))
1044                                                 goto wait_for_memory;
1045                                 }
1046
1047                                 /* Time to copy data. We are close to
1048                                  * the end! */
1049                                 err = skb_copy_to_page_nocache(sk, from, skb,
1050                                                                page, off, copy);
1051                                 if (err) {
1052                                         /* If this page was new, give it to the
1053                                          * socket so it does not get leaked.
1054                                          */
1055                                         if (!TCP_PAGE(sk)) {
1056                                                 TCP_PAGE(sk) = page;
1057                                                 TCP_OFF(sk) = 0;
1058                                         }
1059                                         goto do_error;
1060                                 }
1061
1062                                 /* Update the skb. */
1063                                 if (merge) {
1064                                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1065                                 } else {
1066                                         skb_fill_page_desc(skb, i, page, off, copy);
1067                                         if (TCP_PAGE(sk)) {
1068                                                 get_page(page);
1069                                         } else if (off + copy < PAGE_SIZE) {
1070                                                 get_page(page);
1071                                                 TCP_PAGE(sk) = page;
1072                                         }
1073                                 }
1074
1075                                 TCP_OFF(sk) = off + copy;
1076                         }
1077
1078                         if (!copied)
1079                                 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1080
1081                         tp->write_seq += copy;
1082                         TCP_SKB_CB(skb)->end_seq += copy;
1083                         skb_shinfo(skb)->gso_segs = 0;
1084
1085                         from += copy;
1086                         copied += copy;
1087                         if ((seglen -= copy) == 0 && iovlen == 0)
1088                                 goto out;
1089
1090                         if (skb->len < max || (flags & MSG_OOB))
1091                                 continue;
1092
1093                         if (forced_push(tp)) {
1094                                 tcp_mark_push(tp, skb);
1095                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1096                         } else if (skb == tcp_send_head(sk))
1097                                 tcp_push_one(sk, mss_now);
1098                         continue;
1099
1100 wait_for_sndbuf:
1101                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1102 wait_for_memory:
1103                         if (copied)
1104                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1105
1106                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1107                                 goto do_error;
1108
1109                         mss_now = tcp_send_mss(sk, &size_goal, flags);
1110                 }
1111         }
1112
1113 out:
1114         if (copied)
1115                 tcp_push(sk, flags, mss_now, tp->nonagle);
1116         release_sock(sk);
1117         return copied;
1118
1119 do_fault:
1120         if (!skb->len) {
1121                 tcp_unlink_write_queue(skb, sk);
1122                 /* It is the one place in all of TCP, except connection
1123                  * reset, where we can be unlinking the send_head.
1124                  */
1125                 tcp_check_send_head(sk, skb);
1126                 sk_wmem_free_skb(sk, skb);
1127         }
1128
1129 do_error:
1130         if (copied)
1131                 goto out;
1132 out_err:
1133         err = sk_stream_error(sk, flags, err);
1134         release_sock(sk);
1135         return err;
1136 }
1137 EXPORT_SYMBOL(tcp_sendmsg);
1138
1139 /*
1140  *      Handle reading urgent data. BSD has very simple semantics for
1141  *      this, no blocking and very strange errors 8)
1142  */
1143
1144 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1145 {
1146         struct tcp_sock *tp = tcp_sk(sk);
1147
1148         /* No URG data to read. */
1149         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1150             tp->urg_data == TCP_URG_READ)
1151                 return -EINVAL; /* Yes this is right ! */
1152
1153         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1154                 return -ENOTCONN;
1155
1156         if (tp->urg_data & TCP_URG_VALID) {
1157                 int err = 0;
1158                 char c = tp->urg_data;
1159
1160                 if (!(flags & MSG_PEEK))
1161                         tp->urg_data = TCP_URG_READ;
1162
1163                 /* Read urgent data. */
1164                 msg->msg_flags |= MSG_OOB;
1165
1166                 if (len > 0) {
1167                         if (!(flags & MSG_TRUNC))
1168                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1169                         len = 1;
1170                 } else
1171                         msg->msg_flags |= MSG_TRUNC;
1172
1173                 return err ? -EFAULT : len;
1174         }
1175
1176         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1177                 return 0;
1178
1179         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1180          * the available implementations agree in this case:
1181          * this call should never block, independent of the
1182          * blocking state of the socket.
1183          * Mike <pall@rz.uni-karlsruhe.de>
1184          */
1185         return -EAGAIN;
1186 }
1187
1188 /* Clean up the receive buffer for full frames taken by the user,
1189  * then send an ACK if necessary.  COPIED is the number of bytes
1190  * tcp_recvmsg has given to the user so far, it speeds up the
1191  * calculation of whether or not we must ACK for the sake of
1192  * a window update.
1193  */
1194 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1195 {
1196         struct tcp_sock *tp = tcp_sk(sk);
1197         int time_to_ack = 0;
1198
1199         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1200
1201         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1202              "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1203              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1204
1205         if (inet_csk_ack_scheduled(sk)) {
1206                 const struct inet_connection_sock *icsk = inet_csk(sk);
1207                    /* Delayed ACKs frequently hit locked sockets during bulk
1208                     * receive. */
1209                 if (icsk->icsk_ack.blocked ||
1210                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
1211                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1212                     /*
1213                      * If this read emptied read buffer, we send ACK, if
1214                      * connection is not bidirectional, user drained
1215                      * receive buffer and there was a small segment
1216                      * in queue.
1217                      */
1218                     (copied > 0 &&
1219                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1220                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1221                        !icsk->icsk_ack.pingpong)) &&
1222                       !atomic_read(&sk->sk_rmem_alloc)))
1223                         time_to_ack = 1;
1224         }
1225
1226         /* We send an ACK if we can now advertise a non-zero window
1227          * which has been raised "significantly".
1228          *
1229          * Even if window raised up to infinity, do not send window open ACK
1230          * in states, where we will not receive more. It is useless.
1231          */
1232         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1233                 __u32 rcv_window_now = tcp_receive_window(tp);
1234
1235                 /* Optimize, __tcp_select_window() is not cheap. */
1236                 if (2*rcv_window_now <= tp->window_clamp) {
1237                         __u32 new_window = __tcp_select_window(sk);
1238
1239                         /* Send ACK now, if this read freed lots of space
1240                          * in our buffer. Certainly, new_window is new window.
1241                          * We can advertise it now, if it is not less than current one.
1242                          * "Lots" means "at least twice" here.
1243                          */
1244                         if (new_window && new_window >= 2 * rcv_window_now)
1245                                 time_to_ack = 1;
1246                 }
1247         }
1248         if (time_to_ack)
1249                 tcp_send_ack(sk);
1250 }
1251
1252 static void tcp_prequeue_process(struct sock *sk)
1253 {
1254         struct sk_buff *skb;
1255         struct tcp_sock *tp = tcp_sk(sk);
1256
1257         NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1258
1259         /* RX process wants to run with disabled BHs, though it is not
1260          * necessary */
1261         local_bh_disable();
1262         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1263                 sk_backlog_rcv(sk, skb);
1264         local_bh_enable();
1265
1266         /* Clear memory counter. */
1267         tp->ucopy.memory = 0;
1268 }
1269
1270 #ifdef CONFIG_NET_DMA
1271 static void tcp_service_net_dma(struct sock *sk, bool wait)
1272 {
1273         dma_cookie_t done, used;
1274         dma_cookie_t last_issued;
1275         struct tcp_sock *tp = tcp_sk(sk);
1276
1277         if (!tp->ucopy.dma_chan)
1278                 return;
1279
1280         last_issued = tp->ucopy.dma_cookie;
1281         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1282
1283         do {
1284                 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1285                                               last_issued, &done,
1286                                               &used) == DMA_SUCCESS) {
1287                         /* Safe to free early-copied skbs now */
1288                         __skb_queue_purge(&sk->sk_async_wait_queue);
1289                         break;
1290                 } else {
1291                         struct sk_buff *skb;
1292                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1293                                (dma_async_is_complete(skb->dma_cookie, done,
1294                                                       used) == DMA_SUCCESS)) {
1295                                 __skb_dequeue(&sk->sk_async_wait_queue);
1296                                 kfree_skb(skb);
1297                         }
1298                 }
1299         } while (wait);
1300 }
1301 #endif
1302
1303 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1304 {
1305         struct sk_buff *skb;
1306         u32 offset;
1307
1308         skb_queue_walk(&sk->sk_receive_queue, skb) {
1309                 offset = seq - TCP_SKB_CB(skb)->seq;
1310                 if (tcp_hdr(skb)->syn)
1311                         offset--;
1312                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1313                         *off = offset;
1314                         return skb;
1315                 }
1316         }
1317         return NULL;
1318 }
1319
1320 /*
1321  * This routine provides an alternative to tcp_recvmsg() for routines
1322  * that would like to handle copying from skbuffs directly in 'sendfile'
1323  * fashion.
1324  * Note:
1325  *      - It is assumed that the socket was locked by the caller.
1326  *      - The routine does not block.
1327  *      - At present, there is no support for reading OOB data
1328  *        or for 'peeking' the socket using this routine
1329  *        (although both would be easy to implement).
1330  */
1331 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1332                   sk_read_actor_t recv_actor)
1333 {
1334         struct sk_buff *skb;
1335         struct tcp_sock *tp = tcp_sk(sk);
1336         u32 seq = tp->copied_seq;
1337         u32 offset;
1338         int copied = 0;
1339
1340         if (sk->sk_state == TCP_LISTEN)
1341                 return -ENOTCONN;
1342         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1343                 if (offset < skb->len) {
1344                         int used;
1345                         size_t len;
1346
1347                         len = skb->len - offset;
1348                         /* Stop reading if we hit a patch of urgent data */
1349                         if (tp->urg_data) {
1350                                 u32 urg_offset = tp->urg_seq - seq;
1351                                 if (urg_offset < len)
1352                                         len = urg_offset;
1353                                 if (!len)
1354                                         break;
1355                         }
1356                         used = recv_actor(desc, skb, offset, len);
1357                         if (used < 0) {
1358                                 if (!copied)
1359                                         copied = used;
1360                                 break;
1361                         } else if (used <= len) {
1362                                 seq += used;
1363                                 copied += used;
1364                                 offset += used;
1365                         }
1366                         /*
1367                          * If recv_actor drops the lock (e.g. TCP splice
1368                          * receive) the skb pointer might be invalid when
1369                          * getting here: tcp_collapse might have deleted it
1370                          * while aggregating skbs from the socket queue.
1371                          */
1372                         skb = tcp_recv_skb(sk, seq-1, &offset);
1373                         if (!skb || (offset+1 != skb->len))
1374                                 break;
1375                 }
1376                 if (tcp_hdr(skb)->fin) {
1377                         sk_eat_skb(sk, skb, 0);
1378                         ++seq;
1379                         break;
1380                 }
1381                 sk_eat_skb(sk, skb, 0);
1382                 if (!desc->count)
1383                         break;
1384                 tp->copied_seq = seq;
1385         }
1386         tp->copied_seq = seq;
1387
1388         tcp_rcv_space_adjust(sk);
1389
1390         /* Clean up data we have read: This will do ACK frames. */
1391         if (copied > 0)
1392                 tcp_cleanup_rbuf(sk, copied);
1393         return copied;
1394 }
1395 EXPORT_SYMBOL(tcp_read_sock);
1396
1397 /*
1398  *      This routine copies from a sock struct into the user buffer.
1399  *
1400  *      Technical note: in 2.3 we work on _locked_ socket, so that
1401  *      tricks with *seq access order and skb->users are not required.
1402  *      Probably, code can be easily improved even more.
1403  */
1404
1405 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1406                 size_t len, int nonblock, int flags, int *addr_len)
1407 {
1408         struct tcp_sock *tp = tcp_sk(sk);
1409         int copied = 0;
1410         u32 peek_seq;
1411         u32 *seq;
1412         unsigned long used;
1413         int err;
1414         int target;             /* Read at least this many bytes */
1415         long timeo;
1416         struct task_struct *user_recv = NULL;
1417         int copied_early = 0;
1418         struct sk_buff *skb;
1419         u32 urg_hole = 0;
1420
1421         lock_sock(sk);
1422
1423         err = -ENOTCONN;
1424         if (sk->sk_state == TCP_LISTEN)
1425                 goto out;
1426
1427         timeo = sock_rcvtimeo(sk, nonblock);
1428
1429         /* Urgent data needs to be handled specially. */
1430         if (flags & MSG_OOB)
1431                 goto recv_urg;
1432
1433         seq = &tp->copied_seq;
1434         if (flags & MSG_PEEK) {
1435                 peek_seq = tp->copied_seq;
1436                 seq = &peek_seq;
1437         }
1438
1439         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1440
1441 #ifdef CONFIG_NET_DMA
1442         tp->ucopy.dma_chan = NULL;
1443         preempt_disable();
1444         skb = skb_peek_tail(&sk->sk_receive_queue);
1445         {
1446                 int available = 0;
1447
1448                 if (skb)
1449                         available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1450                 if ((available < target) &&
1451                     (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1452                     !sysctl_tcp_low_latency &&
1453                     dma_find_channel(DMA_MEMCPY)) {
1454                         preempt_enable_no_resched();
1455                         tp->ucopy.pinned_list =
1456                                         dma_pin_iovec_pages(msg->msg_iov, len);
1457                 } else {
1458                         preempt_enable_no_resched();
1459                 }
1460         }
1461 #endif
1462
1463         do {
1464                 u32 offset;
1465
1466                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1467                 if (tp->urg_data && tp->urg_seq == *seq) {
1468                         if (copied)
1469                                 break;
1470                         if (signal_pending(current)) {
1471                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1472                                 break;
1473                         }
1474                 }
1475
1476                 /* Next get a buffer. */
1477
1478                 skb_queue_walk(&sk->sk_receive_queue, skb) {
1479                         /* Now that we have two receive queues this
1480                          * shouldn't happen.
1481                          */
1482                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1483                                  "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1484                                  *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1485                                  flags))
1486                                 break;
1487
1488                         offset = *seq - TCP_SKB_CB(skb)->seq;
1489                         if (tcp_hdr(skb)->syn)
1490                                 offset--;
1491                         if (offset < skb->len)
1492                                 goto found_ok_skb;
1493                         if (tcp_hdr(skb)->fin)
1494                                 goto found_fin_ok;
1495                         WARN(!(flags & MSG_PEEK),
1496                              "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1497                              *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1498                 }
1499
1500                 /* Well, if we have backlog, try to process it now yet. */
1501
1502                 if (copied >= target && !sk->sk_backlog.tail)
1503                         break;
1504
1505                 if (copied) {
1506                         if (sk->sk_err ||
1507                             sk->sk_state == TCP_CLOSE ||
1508                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1509                             !timeo ||
1510                             signal_pending(current))
1511                                 break;
1512                 } else {
1513                         if (sock_flag(sk, SOCK_DONE))
1514                                 break;
1515
1516                         if (sk->sk_err) {
1517                                 copied = sock_error(sk);
1518                                 break;
1519                         }
1520
1521                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1522                                 break;
1523
1524                         if (sk->sk_state == TCP_CLOSE) {
1525                                 if (!sock_flag(sk, SOCK_DONE)) {
1526                                         /* This occurs when user tries to read
1527                                          * from never connected socket.
1528                                          */
1529                                         copied = -ENOTCONN;
1530                                         break;
1531                                 }
1532                                 break;
1533                         }
1534
1535                         if (!timeo) {
1536                                 copied = -EAGAIN;
1537                                 break;
1538                         }
1539
1540                         if (signal_pending(current)) {
1541                                 copied = sock_intr_errno(timeo);
1542                                 break;
1543                         }
1544                 }
1545
1546                 tcp_cleanup_rbuf(sk, copied);
1547
1548                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1549                         /* Install new reader */
1550                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1551                                 user_recv = current;
1552                                 tp->ucopy.task = user_recv;
1553                                 tp->ucopy.iov = msg->msg_iov;
1554                         }
1555
1556                         tp->ucopy.len = len;
1557
1558                         WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1559                                 !(flags & (MSG_PEEK | MSG_TRUNC)));
1560
1561                         /* Ugly... If prequeue is not empty, we have to
1562                          * process it before releasing socket, otherwise
1563                          * order will be broken at second iteration.
1564                          * More elegant solution is required!!!
1565                          *
1566                          * Look: we have the following (pseudo)queues:
1567                          *
1568                          * 1. packets in flight
1569                          * 2. backlog
1570                          * 3. prequeue
1571                          * 4. receive_queue
1572                          *
1573                          * Each queue can be processed only if the next ones
1574                          * are empty. At this point we have empty receive_queue.
1575                          * But prequeue _can_ be not empty after 2nd iteration,
1576                          * when we jumped to start of loop because backlog
1577                          * processing added something to receive_queue.
1578                          * We cannot release_sock(), because backlog contains
1579                          * packets arrived _after_ prequeued ones.
1580                          *
1581                          * Shortly, algorithm is clear --- to process all
1582                          * the queues in order. We could make it more directly,
1583                          * requeueing packets from backlog to prequeue, if
1584                          * is not empty. It is more elegant, but eats cycles,
1585                          * unfortunately.
1586                          */
1587                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1588                                 goto do_prequeue;
1589
1590                         /* __ Set realtime policy in scheduler __ */
1591                 }
1592
1593 #ifdef CONFIG_NET_DMA
1594                 if (tp->ucopy.dma_chan) {
1595                         if (tp->rcv_wnd == 0 &&
1596                             !skb_queue_empty(&sk->sk_async_wait_queue)) {
1597                                 tcp_service_net_dma(sk, true);
1598                                 tcp_cleanup_rbuf(sk, copied);
1599                         } else
1600                                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1601                 }
1602 #endif
1603                 if (copied >= target) {
1604                         /* Do not sleep, just process backlog. */
1605                         release_sock(sk);
1606                         lock_sock(sk);
1607                 } else
1608                         sk_wait_data(sk, &timeo);
1609
1610 #ifdef CONFIG_NET_DMA
1611                 tcp_service_net_dma(sk, false);  /* Don't block */
1612                 tp->ucopy.wakeup = 0;
1613 #endif
1614
1615                 if (user_recv) {
1616                         int chunk;
1617
1618                         /* __ Restore normal policy in scheduler __ */
1619
1620                         if ((chunk = len - tp->ucopy.len) != 0) {
1621                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1622                                 len -= chunk;
1623                                 copied += chunk;
1624                         }
1625
1626                         if (tp->rcv_nxt == tp->copied_seq &&
1627                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1628 do_prequeue:
1629                                 tcp_prequeue_process(sk);
1630
1631                                 if ((chunk = len - tp->ucopy.len) != 0) {
1632                                         NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1633                                         len -= chunk;
1634                                         copied += chunk;
1635                                 }
1636                         }
1637                 }
1638                 if ((flags & MSG_PEEK) &&
1639                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
1640                         if (net_ratelimit())
1641                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1642                                        current->comm, task_pid_nr(current));
1643                         peek_seq = tp->copied_seq;
1644                 }
1645                 continue;
1646
1647         found_ok_skb:
1648                 /* Ok so how much can we use? */
1649                 used = skb->len - offset;
1650                 if (len < used)
1651                         used = len;
1652
1653                 /* Do we have urgent data here? */
1654                 if (tp->urg_data) {
1655                         u32 urg_offset = tp->urg_seq - *seq;
1656                         if (urg_offset < used) {
1657                                 if (!urg_offset) {
1658                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1659                                                 ++*seq;
1660                                                 urg_hole++;
1661                                                 offset++;
1662                                                 used--;
1663                                                 if (!used)
1664                                                         goto skip_copy;
1665                                         }
1666                                 } else
1667                                         used = urg_offset;
1668                         }
1669                 }
1670
1671                 if (!(flags & MSG_TRUNC)) {
1672 #ifdef CONFIG_NET_DMA
1673                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1674                                 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1675
1676                         if (tp->ucopy.dma_chan) {
1677                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1678                                         tp->ucopy.dma_chan, skb, offset,
1679                                         msg->msg_iov, used,
1680                                         tp->ucopy.pinned_list);
1681
1682                                 if (tp->ucopy.dma_cookie < 0) {
1683
1684                                         printk(KERN_ALERT "dma_cookie < 0\n");
1685
1686                                         /* Exception. Bailout! */
1687                                         if (!copied)
1688                                                 copied = -EFAULT;
1689                                         break;
1690                                 }
1691
1692                                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1693
1694                                 if ((offset + used) == skb->len)
1695                                         copied_early = 1;
1696
1697                         } else
1698 #endif
1699                         {
1700                                 err = skb_copy_datagram_iovec(skb, offset,
1701                                                 msg->msg_iov, used);
1702                                 if (err) {
1703                                         /* Exception. Bailout! */
1704                                         if (!copied)
1705                                                 copied = -EFAULT;
1706                                         break;
1707                                 }
1708                         }
1709                 }
1710
1711                 *seq += used;
1712                 copied += used;
1713                 len -= used;
1714
1715                 tcp_rcv_space_adjust(sk);
1716
1717 skip_copy:
1718                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1719                         tp->urg_data = 0;
1720                         tcp_fast_path_check(sk);
1721                 }
1722                 if (used + offset < skb->len)
1723                         continue;
1724
1725                 if (tcp_hdr(skb)->fin)
1726                         goto found_fin_ok;
1727                 if (!(flags & MSG_PEEK)) {
1728                         sk_eat_skb(sk, skb, copied_early);
1729                         copied_early = 0;
1730                 }
1731                 continue;
1732
1733         found_fin_ok:
1734                 /* Process the FIN. */
1735                 ++*seq;
1736                 if (!(flags & MSG_PEEK)) {
1737                         sk_eat_skb(sk, skb, copied_early);
1738                         copied_early = 0;
1739                 }
1740                 break;
1741         } while (len > 0);
1742
1743         if (user_recv) {
1744                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1745                         int chunk;
1746
1747                         tp->ucopy.len = copied > 0 ? len : 0;
1748
1749                         tcp_prequeue_process(sk);
1750
1751                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1752                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1753                                 len -= chunk;
1754                                 copied += chunk;
1755                         }
1756                 }
1757
1758                 tp->ucopy.task = NULL;
1759                 tp->ucopy.len = 0;
1760         }
1761
1762 #ifdef CONFIG_NET_DMA
1763         tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1764         tp->ucopy.dma_chan = NULL;
1765
1766         if (tp->ucopy.pinned_list) {
1767                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1768                 tp->ucopy.pinned_list = NULL;
1769         }
1770 #endif
1771
1772         /* According to UNIX98, msg_name/msg_namelen are ignored
1773          * on connected socket. I was just happy when found this 8) --ANK
1774          */
1775
1776         /* Clean up data we have read: This will do ACK frames. */
1777         tcp_cleanup_rbuf(sk, copied);
1778
1779         release_sock(sk);
1780         return copied;
1781
1782 out:
1783         release_sock(sk);
1784         return err;
1785
1786 recv_urg:
1787         err = tcp_recv_urg(sk, msg, len, flags);
1788         goto out;
1789 }
1790 EXPORT_SYMBOL(tcp_recvmsg);
1791
1792 void tcp_set_state(struct sock *sk, int state)
1793 {
1794         int oldstate = sk->sk_state;
1795
1796         switch (state) {
1797         case TCP_ESTABLISHED:
1798                 if (oldstate != TCP_ESTABLISHED)
1799                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1800                 break;
1801
1802         case TCP_CLOSE:
1803                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1804                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1805
1806                 sk->sk_prot->unhash(sk);
1807                 if (inet_csk(sk)->icsk_bind_hash &&
1808                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1809                         inet_put_port(sk);
1810                 /* fall through */
1811         default:
1812                 if (oldstate == TCP_ESTABLISHED)
1813                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1814         }
1815
1816         /* Change state AFTER socket is unhashed to avoid closed
1817          * socket sitting in hash tables.
1818          */
1819         sk->sk_state = state;
1820
1821 #ifdef STATE_TRACE
1822         SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1823 #endif
1824 }
1825 EXPORT_SYMBOL_GPL(tcp_set_state);
1826
1827 /*
1828  *      State processing on a close. This implements the state shift for
1829  *      sending our FIN frame. Note that we only send a FIN for some
1830  *      states. A shutdown() may have already sent the FIN, or we may be
1831  *      closed.
1832  */
1833
1834 static const unsigned char new_state[16] = {
1835   /* current state:        new state:      action:      */
1836   /* (Invalid)          */ TCP_CLOSE,
1837   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1838   /* TCP_SYN_SENT       */ TCP_CLOSE,
1839   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1840   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1841   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1842   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1843   /* TCP_CLOSE          */ TCP_CLOSE,
1844   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1845   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1846   /* TCP_LISTEN         */ TCP_CLOSE,
1847   /* TCP_CLOSING        */ TCP_CLOSING,
1848 };
1849
1850 static int tcp_close_state(struct sock *sk)
1851 {
1852         int next = (int)new_state[sk->sk_state];
1853         int ns = next & TCP_STATE_MASK;
1854
1855         tcp_set_state(sk, ns);
1856
1857         return next & TCP_ACTION_FIN;
1858 }
1859
1860 /*
1861  *      Shutdown the sending side of a connection. Much like close except
1862  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1863  */
1864
1865 void tcp_shutdown(struct sock *sk, int how)
1866 {
1867         /*      We need to grab some memory, and put together a FIN,
1868          *      and then put it into the queue to be sent.
1869          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1870          */
1871         if (!(how & SEND_SHUTDOWN))
1872                 return;
1873
1874         /* If we've already sent a FIN, or it's a closed state, skip this. */
1875         if ((1 << sk->sk_state) &
1876             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1877              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1878                 /* Clear out any half completed packets.  FIN if needed. */
1879                 if (tcp_close_state(sk))
1880                         tcp_send_fin(sk);
1881         }
1882 }
1883 EXPORT_SYMBOL(tcp_shutdown);
1884
1885 void tcp_close(struct sock *sk, long timeout)
1886 {
1887         struct sk_buff *skb;
1888         int data_was_unread = 0;
1889         int state;
1890
1891         lock_sock(sk);
1892         sk->sk_shutdown = SHUTDOWN_MASK;
1893
1894         if (sk->sk_state == TCP_LISTEN) {
1895                 tcp_set_state(sk, TCP_CLOSE);
1896
1897                 /* Special case. */
1898                 inet_csk_listen_stop(sk);
1899
1900                 goto adjudge_to_death;
1901         }
1902
1903         /*  We need to flush the recv. buffs.  We do this only on the
1904          *  descriptor close, not protocol-sourced closes, because the
1905          *  reader process may not have drained the data yet!
1906          */
1907         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1908                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1909                           tcp_hdr(skb)->fin;
1910                 data_was_unread += len;
1911                 __kfree_skb(skb);
1912         }
1913
1914         sk_mem_reclaim(sk);
1915
1916         /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1917         if (sk->sk_state == TCP_CLOSE)
1918                 goto adjudge_to_death;
1919
1920         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1921          * data was lost. To witness the awful effects of the old behavior of
1922          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1923          * GET in an FTP client, suspend the process, wait for the client to
1924          * advertise a zero window, then kill -9 the FTP client, wheee...
1925          * Note: timeout is always zero in such a case.
1926          */
1927         if (data_was_unread) {
1928                 /* Unread data was tossed, zap the connection. */
1929                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1930                 tcp_set_state(sk, TCP_CLOSE);
1931                 tcp_send_active_reset(sk, sk->sk_allocation);
1932         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1933                 /* Check zero linger _after_ checking for unread data. */
1934                 sk->sk_prot->disconnect(sk, 0);
1935                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1936         } else if (tcp_close_state(sk)) {
1937                 /* We FIN if the application ate all the data before
1938                  * zapping the connection.
1939                  */
1940
1941                 /* RED-PEN. Formally speaking, we have broken TCP state
1942                  * machine. State transitions:
1943                  *
1944                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1945                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1946                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1947                  *
1948                  * are legal only when FIN has been sent (i.e. in window),
1949                  * rather than queued out of window. Purists blame.
1950                  *
1951                  * F.e. "RFC state" is ESTABLISHED,
1952                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1953                  *
1954                  * The visible declinations are that sometimes
1955                  * we enter time-wait state, when it is not required really
1956                  * (harmless), do not send active resets, when they are
1957                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1958                  * they look as CLOSING or LAST_ACK for Linux)
1959                  * Probably, I missed some more holelets.
1960                  *                                              --ANK
1961                  */
1962                 tcp_send_fin(sk);
1963         }
1964
1965         sk_stream_wait_close(sk, timeout);
1966
1967 adjudge_to_death:
1968         state = sk->sk_state;
1969         sock_hold(sk);
1970         sock_orphan(sk);
1971
1972         /* It is the last release_sock in its life. It will remove backlog. */
1973         release_sock(sk);
1974
1975
1976         /* Now socket is owned by kernel and we acquire BH lock
1977            to finish close. No need to check for user refs.
1978          */
1979         local_bh_disable();
1980         bh_lock_sock(sk);
1981         WARN_ON(sock_owned_by_user(sk));
1982
1983         percpu_counter_inc(sk->sk_prot->orphan_count);
1984
1985         /* Have we already been destroyed by a softirq or backlog? */
1986         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1987                 goto out;
1988
1989         /*      This is a (useful) BSD violating of the RFC. There is a
1990          *      problem with TCP as specified in that the other end could
1991          *      keep a socket open forever with no application left this end.
1992          *      We use a 3 minute timeout (about the same as BSD) then kill
1993          *      our end. If they send after that then tough - BUT: long enough
1994          *      that we won't make the old 4*rto = almost no time - whoops
1995          *      reset mistake.
1996          *
1997          *      Nope, it was not mistake. It is really desired behaviour
1998          *      f.e. on http servers, when such sockets are useless, but
1999          *      consume significant resources. Let's do it with special
2000          *      linger2 option.                                 --ANK
2001          */
2002
2003         if (sk->sk_state == TCP_FIN_WAIT2) {
2004                 struct tcp_sock *tp = tcp_sk(sk);
2005                 if (tp->linger2 < 0) {
2006                         tcp_set_state(sk, TCP_CLOSE);
2007                         tcp_send_active_reset(sk, GFP_ATOMIC);
2008                         NET_INC_STATS_BH(sock_net(sk),
2009                                         LINUX_MIB_TCPABORTONLINGER);
2010                 } else {
2011                         const int tmo = tcp_fin_time(sk);
2012
2013                         if (tmo > TCP_TIMEWAIT_LEN) {
2014                                 inet_csk_reset_keepalive_timer(sk,
2015                                                 tmo - TCP_TIMEWAIT_LEN);
2016                         } else {
2017                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2018                                 goto out;
2019                         }
2020                 }
2021         }
2022         if (sk->sk_state != TCP_CLOSE) {
2023                 sk_mem_reclaim(sk);
2024                 if (tcp_too_many_orphans(sk, 0)) {
2025                         if (net_ratelimit())
2026                                 printk(KERN_INFO "TCP: too many of orphaned "
2027                                        "sockets\n");
2028                         tcp_set_state(sk, TCP_CLOSE);
2029                         tcp_send_active_reset(sk, GFP_ATOMIC);
2030                         NET_INC_STATS_BH(sock_net(sk),
2031                                         LINUX_MIB_TCPABORTONMEMORY);
2032                 }
2033         }
2034
2035         if (sk->sk_state == TCP_CLOSE)
2036                 inet_csk_destroy_sock(sk);
2037         /* Otherwise, socket is reprieved until protocol close. */
2038
2039 out:
2040         bh_unlock_sock(sk);
2041         local_bh_enable();
2042         sock_put(sk);
2043 }
2044 EXPORT_SYMBOL(tcp_close);
2045
2046 /* These states need RST on ABORT according to RFC793 */
2047
2048 static inline int tcp_need_reset(int state)
2049 {
2050         return (1 << state) &
2051                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2052                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2053 }
2054
2055 int tcp_disconnect(struct sock *sk, int flags)
2056 {
2057         struct inet_sock *inet = inet_sk(sk);
2058         struct inet_connection_sock *icsk = inet_csk(sk);
2059         struct tcp_sock *tp = tcp_sk(sk);
2060         int err = 0;
2061         int old_state = sk->sk_state;
2062
2063         if (old_state != TCP_CLOSE)
2064                 tcp_set_state(sk, TCP_CLOSE);
2065
2066         /* ABORT function of RFC793 */
2067         if (old_state == TCP_LISTEN) {
2068                 inet_csk_listen_stop(sk);
2069         } else if (tcp_need_reset(old_state) ||
2070                    (tp->snd_nxt != tp->write_seq &&
2071                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2072                 /* The last check adjusts for discrepancy of Linux wrt. RFC
2073                  * states
2074                  */
2075                 tcp_send_active_reset(sk, gfp_any());
2076                 sk->sk_err = ECONNRESET;
2077         } else if (old_state == TCP_SYN_SENT)
2078                 sk->sk_err = ECONNRESET;
2079
2080         tcp_clear_xmit_timers(sk);
2081         __skb_queue_purge(&sk->sk_receive_queue);
2082         tcp_write_queue_purge(sk);
2083         __skb_queue_purge(&tp->out_of_order_queue);
2084 #ifdef CONFIG_NET_DMA
2085         __skb_queue_purge(&sk->sk_async_wait_queue);
2086 #endif
2087
2088         inet->inet_dport = 0;
2089
2090         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2091                 inet_reset_saddr(sk);
2092
2093         sk->sk_shutdown = 0;
2094         sock_reset_flag(sk, SOCK_DONE);
2095         tp->srtt = 0;
2096         if ((tp->write_seq += tp->max_window + 2) == 0)
2097                 tp->write_seq = 1;
2098         icsk->icsk_backoff = 0;
2099         tp->snd_cwnd = 2;
2100         icsk->icsk_probes_out = 0;
2101         tp->packets_out = 0;
2102         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2103         tp->snd_cwnd_cnt = 0;
2104         tp->bytes_acked = 0;
2105         tp->window_clamp = 0;
2106         tcp_set_ca_state(sk, TCP_CA_Open);
2107         tcp_clear_retrans(tp);
2108         inet_csk_delack_init(sk);
2109         tcp_init_send_head(sk);
2110         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2111         __sk_dst_reset(sk);
2112
2113         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2114
2115         sk->sk_error_report(sk);
2116         return err;
2117 }
2118 EXPORT_SYMBOL(tcp_disconnect);
2119
2120 /*
2121  *      Socket option code for TCP.
2122  */
2123 static int do_tcp_setsockopt(struct sock *sk, int level,
2124                 int optname, char __user *optval, unsigned int optlen)
2125 {
2126         struct tcp_sock *tp = tcp_sk(sk);
2127         struct inet_connection_sock *icsk = inet_csk(sk);
2128         int val;
2129         int err = 0;
2130
2131         /* These are data/string values, all the others are ints */
2132         switch (optname) {
2133         case TCP_CONGESTION: {
2134                 char name[TCP_CA_NAME_MAX];
2135
2136                 if (optlen < 1)
2137                         return -EINVAL;
2138
2139                 val = strncpy_from_user(name, optval,
2140                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
2141                 if (val < 0)
2142                         return -EFAULT;
2143                 name[val] = 0;
2144
2145                 lock_sock(sk);
2146                 err = tcp_set_congestion_control(sk, name);
2147                 release_sock(sk);
2148                 return err;
2149         }
2150         case TCP_COOKIE_TRANSACTIONS: {
2151                 struct tcp_cookie_transactions ctd;
2152                 struct tcp_cookie_values *cvp = NULL;
2153
2154                 if (sizeof(ctd) > optlen)
2155                         return -EINVAL;
2156                 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2157                         return -EFAULT;
2158
2159                 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2160                     ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2161                         return -EINVAL;
2162
2163                 if (ctd.tcpct_cookie_desired == 0) {
2164                         /* default to global value */
2165                 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2166                            ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2167                            ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2168                         return -EINVAL;
2169                 }
2170
2171                 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2172                         /* Supercedes all other values */
2173                         lock_sock(sk);
2174                         if (tp->cookie_values != NULL) {
2175                                 kref_put(&tp->cookie_values->kref,
2176                                          tcp_cookie_values_release);
2177                                 tp->cookie_values = NULL;
2178                         }
2179                         tp->rx_opt.cookie_in_always = 0; /* false */
2180                         tp->rx_opt.cookie_out_never = 1; /* true */
2181                         release_sock(sk);
2182                         return err;
2183                 }
2184
2185                 /* Allocate ancillary memory before locking.
2186                  */
2187                 if (ctd.tcpct_used > 0 ||
2188                     (tp->cookie_values == NULL &&
2189                      (sysctl_tcp_cookie_size > 0 ||
2190                       ctd.tcpct_cookie_desired > 0 ||
2191                       ctd.tcpct_s_data_desired > 0))) {
2192                         cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2193                                       GFP_KERNEL);
2194                         if (cvp == NULL)
2195                                 return -ENOMEM;
2196
2197                         kref_init(&cvp->kref);
2198                 }
2199                 lock_sock(sk);
2200                 tp->rx_opt.cookie_in_always =
2201                         (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2202                 tp->rx_opt.cookie_out_never = 0; /* false */
2203
2204                 if (tp->cookie_values != NULL) {
2205                         if (cvp != NULL) {
2206                                 /* Changed values are recorded by a changed
2207                                  * pointer, ensuring the cookie will differ,
2208                                  * without separately hashing each value later.
2209                                  */
2210                                 kref_put(&tp->cookie_values->kref,
2211                                          tcp_cookie_values_release);
2212                         } else {
2213                                 cvp = tp->cookie_values;
2214                         }
2215                 }
2216
2217                 if (cvp != NULL) {
2218                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
2219
2220                         if (ctd.tcpct_used > 0) {
2221                                 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2222                                        ctd.tcpct_used);
2223                                 cvp->s_data_desired = ctd.tcpct_used;
2224                                 cvp->s_data_constant = 1; /* true */
2225                         } else {
2226                                 /* No constant payload data. */
2227                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2228                                 cvp->s_data_constant = 0; /* false */
2229                         }
2230
2231                         tp->cookie_values = cvp;
2232                 }
2233                 release_sock(sk);
2234                 return err;
2235         }
2236         default:
2237                 /* fallthru */
2238                 break;
2239         }
2240
2241         if (optlen < sizeof(int))
2242                 return -EINVAL;
2243
2244         if (get_user(val, (int __user *)optval))
2245                 return -EFAULT;
2246
2247         lock_sock(sk);
2248
2249         switch (optname) {
2250         case TCP_MAXSEG:
2251                 /* Values greater than interface MTU won't take effect. However
2252                  * at the point when this call is done we typically don't yet
2253                  * know which interface is going to be used */
2254                 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2255                         err = -EINVAL;
2256                         break;
2257                 }
2258                 tp->rx_opt.user_mss = val;
2259                 break;
2260
2261         case TCP_NODELAY:
2262                 if (val) {
2263                         /* TCP_NODELAY is weaker than TCP_CORK, so that
2264                          * this option on corked socket is remembered, but
2265                          * it is not activated until cork is cleared.
2266                          *
2267                          * However, when TCP_NODELAY is set we make
2268                          * an explicit push, which overrides even TCP_CORK
2269                          * for currently queued segments.
2270                          */
2271                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2272                         tcp_push_pending_frames(sk);
2273                 } else {
2274                         tp->nonagle &= ~TCP_NAGLE_OFF;
2275                 }
2276                 break;
2277
2278         case TCP_THIN_LINEAR_TIMEOUTS:
2279                 if (val < 0 || val > 1)
2280                         err = -EINVAL;
2281                 else
2282                         tp->thin_lto = val;
2283                 break;
2284
2285         case TCP_THIN_DUPACK:
2286                 if (val < 0 || val > 1)
2287                         err = -EINVAL;
2288                 else
2289                         tp->thin_dupack = val;
2290                 break;
2291
2292         case TCP_CORK:
2293                 /* When set indicates to always queue non-full frames.
2294                  * Later the user clears this option and we transmit
2295                  * any pending partial frames in the queue.  This is
2296                  * meant to be used alongside sendfile() to get properly
2297                  * filled frames when the user (for example) must write
2298                  * out headers with a write() call first and then use
2299                  * sendfile to send out the data parts.
2300                  *
2301                  * TCP_CORK can be set together with TCP_NODELAY and it is
2302                  * stronger than TCP_NODELAY.
2303                  */
2304                 if (val) {
2305                         tp->nonagle |= TCP_NAGLE_CORK;
2306                 } else {
2307                         tp->nonagle &= ~TCP_NAGLE_CORK;
2308                         if (tp->nonagle&TCP_NAGLE_OFF)
2309                                 tp->nonagle |= TCP_NAGLE_PUSH;
2310                         tcp_push_pending_frames(sk);
2311                 }
2312                 break;
2313
2314         case TCP_KEEPIDLE:
2315                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2316                         err = -EINVAL;
2317                 else {
2318                         tp->keepalive_time = val * HZ;
2319                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
2320                             !((1 << sk->sk_state) &
2321                               (TCPF_CLOSE | TCPF_LISTEN))) {
2322                                 u32 elapsed = keepalive_time_elapsed(tp);
2323                                 if (tp->keepalive_time > elapsed)
2324                                         elapsed = tp->keepalive_time - elapsed;
2325                                 else
2326                                         elapsed = 0;
2327                                 inet_csk_reset_keepalive_timer(sk, elapsed);
2328                         }
2329                 }
2330                 break;
2331         case TCP_KEEPINTVL:
2332                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2333                         err = -EINVAL;
2334                 else
2335                         tp->keepalive_intvl = val * HZ;
2336                 break;
2337         case TCP_KEEPCNT:
2338                 if (val < 1 || val > MAX_TCP_KEEPCNT)
2339                         err = -EINVAL;
2340                 else
2341                         tp->keepalive_probes = val;
2342                 break;
2343         case TCP_SYNCNT:
2344                 if (val < 1 || val > MAX_TCP_SYNCNT)
2345                         err = -EINVAL;
2346                 else
2347                         icsk->icsk_syn_retries = val;
2348                 break;
2349
2350         case TCP_LINGER2:
2351                 if (val < 0)
2352                         tp->linger2 = -1;
2353                 else if (val > sysctl_tcp_fin_timeout / HZ)
2354                         tp->linger2 = 0;
2355                 else
2356                         tp->linger2 = val * HZ;
2357                 break;
2358
2359         case TCP_DEFER_ACCEPT:
2360                 /* Translate value in seconds to number of retransmits */
2361                 icsk->icsk_accept_queue.rskq_defer_accept =
2362                         secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2363                                         TCP_RTO_MAX / HZ);
2364                 break;
2365
2366         case TCP_WINDOW_CLAMP:
2367                 if (!val) {
2368                         if (sk->sk_state != TCP_CLOSE) {
2369                                 err = -EINVAL;
2370                                 break;
2371                         }
2372                         tp->window_clamp = 0;
2373                 } else
2374                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2375                                                 SOCK_MIN_RCVBUF / 2 : val;
2376                 break;
2377
2378         case TCP_QUICKACK:
2379                 if (!val) {
2380                         icsk->icsk_ack.pingpong = 1;
2381                 } else {
2382                         icsk->icsk_ack.pingpong = 0;
2383                         if ((1 << sk->sk_state) &
2384                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2385                             inet_csk_ack_scheduled(sk)) {
2386                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2387                                 tcp_cleanup_rbuf(sk, 1);
2388                                 if (!(val & 1))
2389                                         icsk->icsk_ack.pingpong = 1;
2390                         }
2391                 }
2392                 break;
2393
2394 #ifdef CONFIG_TCP_MD5SIG
2395         case TCP_MD5SIG:
2396                 /* Read the IP->Key mappings from userspace */
2397                 err = tp->af_specific->md5_parse(sk, optval, optlen);
2398                 break;
2399 #endif
2400         case TCP_USER_TIMEOUT:
2401                 /* Cap the max timeout in ms TCP will retry/retrans
2402                  * before giving up and aborting (ETIMEDOUT) a connection.
2403                  */
2404                 if (val < 0)
2405                         err = -EINVAL;
2406                 else
2407                         icsk->icsk_user_timeout = msecs_to_jiffies(val);
2408                 break;
2409         default:
2410                 err = -ENOPROTOOPT;
2411                 break;
2412         }
2413
2414         release_sock(sk);
2415         return err;
2416 }
2417
2418 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2419                    unsigned int optlen)
2420 {
2421         const struct inet_connection_sock *icsk = inet_csk(sk);
2422
2423         if (level != SOL_TCP)
2424                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2425                                                      optval, optlen);
2426         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2427 }
2428 EXPORT_SYMBOL(tcp_setsockopt);
2429
2430 #ifdef CONFIG_COMPAT
2431 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2432                           char __user *optval, unsigned int optlen)
2433 {
2434         if (level != SOL_TCP)
2435                 return inet_csk_compat_setsockopt(sk, level, optname,
2436                                                   optval, optlen);
2437         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2438 }
2439 EXPORT_SYMBOL(compat_tcp_setsockopt);
2440 #endif
2441
2442 /* Return information about state of tcp endpoint in API format. */
2443 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2444 {
2445         const struct tcp_sock *tp = tcp_sk(sk);
2446         const struct inet_connection_sock *icsk = inet_csk(sk);
2447         u32 now = tcp_time_stamp;
2448
2449         memset(info, 0, sizeof(*info));
2450
2451         info->tcpi_state = sk->sk_state;
2452         info->tcpi_ca_state = icsk->icsk_ca_state;
2453         info->tcpi_retransmits = icsk->icsk_retransmits;
2454         info->tcpi_probes = icsk->icsk_probes_out;
2455         info->tcpi_backoff = icsk->icsk_backoff;
2456
2457         if (tp->rx_opt.tstamp_ok)
2458                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2459         if (tcp_is_sack(tp))
2460                 info->tcpi_options |= TCPI_OPT_SACK;
2461         if (tp->rx_opt.wscale_ok) {
2462                 info->tcpi_options |= TCPI_OPT_WSCALE;
2463                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2464                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2465         }
2466
2467         if (tp->ecn_flags & TCP_ECN_OK)
2468                 info->tcpi_options |= TCPI_OPT_ECN;
2469         if (tp->ecn_flags & TCP_ECN_SEEN)
2470                 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2471
2472         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2473         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2474         info->tcpi_snd_mss = tp->mss_cache;
2475         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2476
2477         if (sk->sk_state == TCP_LISTEN) {
2478                 info->tcpi_unacked = sk->sk_ack_backlog;
2479                 info->tcpi_sacked = sk->sk_max_ack_backlog;
2480         } else {
2481                 info->tcpi_unacked = tp->packets_out;
2482                 info->tcpi_sacked = tp->sacked_out;
2483         }
2484         info->tcpi_lost = tp->lost_out;
2485         info->tcpi_retrans = tp->retrans_out;
2486         info->tcpi_fackets = tp->fackets_out;
2487
2488         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2489         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2490         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2491
2492         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2493         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2494         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2495         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2496         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2497         info->tcpi_snd_cwnd = tp->snd_cwnd;
2498         info->tcpi_advmss = tp->advmss;
2499         info->tcpi_reordering = tp->reordering;
2500
2501         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2502         info->tcpi_rcv_space = tp->rcvq_space.space;
2503
2504         info->tcpi_total_retrans = tp->total_retrans;
2505 }
2506 EXPORT_SYMBOL_GPL(tcp_get_info);
2507
2508 static int do_tcp_getsockopt(struct sock *sk, int level,
2509                 int optname, char __user *optval, int __user *optlen)
2510 {
2511         struct inet_connection_sock *icsk = inet_csk(sk);
2512         struct tcp_sock *tp = tcp_sk(sk);
2513         int val, len;
2514
2515         if (get_user(len, optlen))
2516                 return -EFAULT;
2517
2518         len = min_t(unsigned int, len, sizeof(int));
2519
2520         if (len < 0)
2521                 return -EINVAL;
2522
2523         switch (optname) {
2524         case TCP_MAXSEG:
2525                 val = tp->mss_cache;
2526                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2527                         val = tp->rx_opt.user_mss;
2528                 break;
2529         case TCP_NODELAY:
2530                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2531                 break;
2532         case TCP_CORK:
2533                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2534                 break;
2535         case TCP_KEEPIDLE:
2536                 val = keepalive_time_when(tp) / HZ;
2537                 break;
2538         case TCP_KEEPINTVL:
2539                 val = keepalive_intvl_when(tp) / HZ;
2540                 break;
2541         case TCP_KEEPCNT:
2542                 val = keepalive_probes(tp);
2543                 break;
2544         case TCP_SYNCNT:
2545                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2546                 break;
2547         case TCP_LINGER2:
2548                 val = tp->linger2;
2549                 if (val >= 0)
2550                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2551                 break;
2552         case TCP_DEFER_ACCEPT:
2553                 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2554                                       TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2555                 break;
2556         case TCP_WINDOW_CLAMP:
2557                 val = tp->window_clamp;
2558                 break;
2559         case TCP_INFO: {
2560                 struct tcp_info info;
2561
2562                 if (get_user(len, optlen))
2563                         return -EFAULT;
2564
2565                 tcp_get_info(sk, &info);
2566
2567                 len = min_t(unsigned int, len, sizeof(info));
2568                 if (put_user(len, optlen))
2569                         return -EFAULT;
2570                 if (copy_to_user(optval, &info, len))
2571                         return -EFAULT;
2572                 return 0;
2573         }
2574         case TCP_QUICKACK:
2575                 val = !icsk->icsk_ack.pingpong;
2576                 break;
2577
2578         case TCP_CONGESTION:
2579                 if (get_user(len, optlen))
2580                         return -EFAULT;
2581                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2582                 if (put_user(len, optlen))
2583                         return -EFAULT;
2584                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2585                         return -EFAULT;
2586                 return 0;
2587
2588         case TCP_COOKIE_TRANSACTIONS: {
2589                 struct tcp_cookie_transactions ctd;
2590                 struct tcp_cookie_values *cvp = tp->cookie_values;
2591
2592                 if (get_user(len, optlen))
2593                         return -EFAULT;
2594                 if (len < sizeof(ctd))
2595                         return -EINVAL;
2596
2597                 memset(&ctd, 0, sizeof(ctd));
2598                 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2599                                    TCP_COOKIE_IN_ALWAYS : 0)
2600                                 | (tp->rx_opt.cookie_out_never ?
2601                                    TCP_COOKIE_OUT_NEVER : 0);
2602
2603                 if (cvp != NULL) {
2604                         ctd.tcpct_flags |= (cvp->s_data_in ?
2605                                             TCP_S_DATA_IN : 0)
2606                                          | (cvp->s_data_out ?
2607                                             TCP_S_DATA_OUT : 0);
2608
2609                         ctd.tcpct_cookie_desired = cvp->cookie_desired;
2610                         ctd.tcpct_s_data_desired = cvp->s_data_desired;
2611
2612                         memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2613                                cvp->cookie_pair_size);
2614                         ctd.tcpct_used = cvp->cookie_pair_size;
2615                 }
2616
2617                 if (put_user(sizeof(ctd), optlen))
2618                         return -EFAULT;
2619                 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2620                         return -EFAULT;
2621                 return 0;
2622         }
2623         case TCP_THIN_LINEAR_TIMEOUTS:
2624                 val = tp->thin_lto;
2625                 break;
2626         case TCP_THIN_DUPACK:
2627                 val = tp->thin_dupack;
2628                 break;
2629
2630         case TCP_USER_TIMEOUT:
2631                 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2632                 break;
2633         default:
2634                 return -ENOPROTOOPT;
2635         }
2636
2637         if (put_user(len, optlen))
2638                 return -EFAULT;
2639         if (copy_to_user(optval, &val, len))
2640                 return -EFAULT;
2641         return 0;
2642 }
2643
2644 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2645                    int __user *optlen)
2646 {
2647         struct inet_connection_sock *icsk = inet_csk(sk);
2648
2649         if (level != SOL_TCP)
2650                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2651                                                      optval, optlen);
2652         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2653 }
2654 EXPORT_SYMBOL(tcp_getsockopt);
2655
2656 #ifdef CONFIG_COMPAT
2657 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2658                           char __user *optval, int __user *optlen)
2659 {
2660         if (level != SOL_TCP)
2661                 return inet_csk_compat_getsockopt(sk, level, optname,
2662                                                   optval, optlen);
2663         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2664 }
2665 EXPORT_SYMBOL(compat_tcp_getsockopt);
2666 #endif
2667
2668 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, u32 features)
2669 {
2670         struct sk_buff *segs = ERR_PTR(-EINVAL);
2671         struct tcphdr *th;
2672         unsigned thlen;
2673         unsigned int seq;
2674         __be32 delta;
2675         unsigned int oldlen;
2676         unsigned int mss;
2677
2678         if (!pskb_may_pull(skb, sizeof(*th)))
2679                 goto out;
2680
2681         th = tcp_hdr(skb);
2682         thlen = th->doff * 4;
2683         if (thlen < sizeof(*th))
2684                 goto out;
2685
2686         if (!pskb_may_pull(skb, thlen))
2687                 goto out;
2688
2689         oldlen = (u16)~skb->len;
2690         __skb_pull(skb, thlen);
2691
2692         mss = skb_shinfo(skb)->gso_size;
2693         if (unlikely(skb->len <= mss))
2694                 goto out;
2695
2696         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2697                 /* Packet is from an untrusted source, reset gso_segs. */
2698                 int type = skb_shinfo(skb)->gso_type;
2699
2700                 if (unlikely(type &
2701                              ~(SKB_GSO_TCPV4 |
2702                                SKB_GSO_DODGY |
2703                                SKB_GSO_TCP_ECN |
2704                                SKB_GSO_TCPV6 |
2705                                0) ||
2706                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2707                         goto out;
2708
2709                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2710
2711                 segs = NULL;
2712                 goto out;
2713         }
2714
2715         segs = skb_segment(skb, features);
2716         if (IS_ERR(segs))
2717                 goto out;
2718
2719         delta = htonl(oldlen + (thlen + mss));
2720
2721         skb = segs;
2722         th = tcp_hdr(skb);
2723         seq = ntohl(th->seq);
2724
2725         do {
2726                 th->fin = th->psh = 0;
2727
2728                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2729                                        (__force u32)delta));
2730                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2731                         th->check =
2732                              csum_fold(csum_partial(skb_transport_header(skb),
2733                                                     thlen, skb->csum));
2734
2735                 seq += mss;
2736                 skb = skb->next;
2737                 th = tcp_hdr(skb);
2738
2739                 th->seq = htonl(seq);
2740                 th->cwr = 0;
2741         } while (skb->next);
2742
2743         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2744                       skb->data_len);
2745         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2746                                 (__force u32)delta));
2747         if (skb->ip_summed != CHECKSUM_PARTIAL)
2748                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2749                                                    thlen, skb->csum));
2750
2751 out:
2752         return segs;
2753 }
2754 EXPORT_SYMBOL(tcp_tso_segment);
2755
2756 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2757 {
2758         struct sk_buff **pp = NULL;
2759         struct sk_buff *p;
2760         struct tcphdr *th;
2761         struct tcphdr *th2;
2762         unsigned int len;
2763         unsigned int thlen;
2764         __be32 flags;
2765         unsigned int mss = 1;
2766         unsigned int hlen;
2767         unsigned int off;
2768         int flush = 1;
2769         int i;
2770
2771         off = skb_gro_offset(skb);
2772         hlen = off + sizeof(*th);
2773         th = skb_gro_header_fast(skb, off);
2774         if (skb_gro_header_hard(skb, hlen)) {
2775                 th = skb_gro_header_slow(skb, hlen, off);
2776                 if (unlikely(!th))
2777                         goto out;
2778         }
2779
2780         thlen = th->doff * 4;
2781         if (thlen < sizeof(*th))
2782                 goto out;
2783
2784         hlen = off + thlen;
2785         if (skb_gro_header_hard(skb, hlen)) {
2786                 th = skb_gro_header_slow(skb, hlen, off);
2787                 if (unlikely(!th))
2788                         goto out;
2789         }
2790
2791         skb_gro_pull(skb, thlen);
2792
2793         len = skb_gro_len(skb);
2794         flags = tcp_flag_word(th);
2795
2796         for (; (p = *head); head = &p->next) {
2797                 if (!NAPI_GRO_CB(p)->same_flow)
2798                         continue;
2799
2800                 th2 = tcp_hdr(p);
2801
2802                 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2803                         NAPI_GRO_CB(p)->same_flow = 0;
2804                         continue;
2805                 }
2806
2807                 goto found;
2808         }
2809
2810         goto out_check_final;
2811
2812 found:
2813         flush = NAPI_GRO_CB(p)->flush;
2814         flush |= (__force int)(flags & TCP_FLAG_CWR);
2815         flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2816                   ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2817         flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2818         for (i = sizeof(*th); i < thlen; i += 4)
2819                 flush |= *(u32 *)((u8 *)th + i) ^
2820                          *(u32 *)((u8 *)th2 + i);
2821
2822         mss = skb_shinfo(p)->gso_size;
2823
2824         flush |= (len - 1) >= mss;
2825         flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2826
2827         if (flush || skb_gro_receive(head, skb)) {
2828                 mss = 1;
2829                 goto out_check_final;
2830         }
2831
2832         p = *head;
2833         th2 = tcp_hdr(p);
2834         tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2835
2836 out_check_final:
2837         flush = len < mss;
2838         flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2839                                         TCP_FLAG_RST | TCP_FLAG_SYN |
2840                                         TCP_FLAG_FIN));
2841
2842         if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2843                 pp = head;
2844
2845 out:
2846         NAPI_GRO_CB(skb)->flush |= flush;
2847
2848         return pp;
2849 }
2850 EXPORT_SYMBOL(tcp_gro_receive);
2851
2852 int tcp_gro_complete(struct sk_buff *skb)
2853 {
2854         struct tcphdr *th = tcp_hdr(skb);
2855
2856         skb->csum_start = skb_transport_header(skb) - skb->head;
2857         skb->csum_offset = offsetof(struct tcphdr, check);
2858         skb->ip_summed = CHECKSUM_PARTIAL;
2859
2860         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2861
2862         if (th->cwr)
2863                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2864
2865         return 0;
2866 }
2867 EXPORT_SYMBOL(tcp_gro_complete);
2868
2869 #ifdef CONFIG_TCP_MD5SIG
2870 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2871 static DEFINE_MUTEX(tcp_md5sig_mutex);
2872 static bool tcp_md5sig_pool_populated = false;
2873
2874 static void __tcp_alloc_md5sig_pool(void)
2875 {
2876         int cpu;
2877
2878         for_each_possible_cpu(cpu) {
2879                 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
2880                         struct crypto_hash *hash;
2881
2882                         hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2883                         if (IS_ERR_OR_NULL(hash))
2884                                 return;
2885                         per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
2886                 }
2887         }
2888         /* before setting tcp_md5sig_pool_populated, we must commit all writes
2889          * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2890          */
2891         smp_wmb();
2892         tcp_md5sig_pool_populated = true;
2893 }
2894
2895 bool tcp_alloc_md5sig_pool(void)
2896 {
2897         if (unlikely(!tcp_md5sig_pool_populated)) {
2898                 mutex_lock(&tcp_md5sig_mutex);
2899
2900                 if (!tcp_md5sig_pool_populated)
2901                         __tcp_alloc_md5sig_pool();
2902
2903                 mutex_unlock(&tcp_md5sig_mutex);
2904         }
2905         return tcp_md5sig_pool_populated;
2906 }
2907 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2908
2909
2910 /**
2911  *      tcp_get_md5sig_pool - get md5sig_pool for this user
2912  *
2913  *      We use percpu structure, so if we succeed, we exit with preemption
2914  *      and BH disabled, to make sure another thread or softirq handling
2915  *      wont try to get same context.
2916  */
2917 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2918 {
2919         local_bh_disable();
2920
2921         if (tcp_md5sig_pool_populated) {
2922                 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
2923                 smp_rmb();
2924                 return this_cpu_ptr(&tcp_md5sig_pool);
2925         }
2926         local_bh_enable();
2927         return NULL;
2928 }
2929 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2930
2931 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2932                         const struct tcphdr *th)
2933 {
2934         struct scatterlist sg;
2935         struct tcphdr hdr;
2936         int err;
2937
2938         /* We are not allowed to change tcphdr, make a local copy */
2939         memcpy(&hdr, th, sizeof(hdr));
2940         hdr.check = 0;
2941
2942         /* options aren't included in the hash */
2943         sg_init_one(&sg, &hdr, sizeof(hdr));
2944         err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2945         return err;
2946 }
2947 EXPORT_SYMBOL(tcp_md5_hash_header);
2948
2949 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2950                           const struct sk_buff *skb, unsigned int header_len)
2951 {
2952         struct scatterlist sg;
2953         const struct tcphdr *tp = tcp_hdr(skb);
2954         struct hash_desc *desc = &hp->md5_desc;
2955         unsigned i;
2956         const unsigned head_data_len = skb_headlen(skb) > header_len ?
2957                                        skb_headlen(skb) - header_len : 0;
2958         const struct skb_shared_info *shi = skb_shinfo(skb);
2959         struct sk_buff *frag_iter;
2960
2961         sg_init_table(&sg, 1);
2962
2963         sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2964         if (crypto_hash_update(desc, &sg, head_data_len))
2965                 return 1;
2966
2967         for (i = 0; i < shi->nr_frags; ++i) {
2968                 const struct skb_frag_struct *f = &shi->frags[i];
2969                 unsigned int offset = f->page_offset;
2970                 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
2971
2972                 sg_set_page(&sg, page, skb_frag_size(f),
2973                             offset_in_page(offset));
2974                 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2975                         return 1;
2976         }
2977
2978         skb_walk_frags(skb, frag_iter)
2979                 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
2980                         return 1;
2981
2982         return 0;
2983 }
2984 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2985