tcp.c revision 9fa5fdf291c9b58b1cb8b4bb2a0ee57efa21d635
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> 267 268#include <net/icmp.h> 269#include <net/tcp.h> 270#include <net/xfrm.h> 271#include <net/ip.h> 272#include <net/netdma.h> 273#include <net/sock.h> 274 275#include <asm/uaccess.h> 276#include <asm/ioctls.h> 277 278int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 279 280struct percpu_counter tcp_orphan_count; 281EXPORT_SYMBOL_GPL(tcp_orphan_count); 282 283int sysctl_tcp_mem[3] __read_mostly; 284int sysctl_tcp_wmem[3] __read_mostly; 285int sysctl_tcp_rmem[3] __read_mostly; 286 287EXPORT_SYMBOL(sysctl_tcp_mem); 288EXPORT_SYMBOL(sysctl_tcp_rmem); 289EXPORT_SYMBOL(sysctl_tcp_wmem); 290 291atomic_t tcp_memory_allocated; /* Current allocated memory. */ 292EXPORT_SYMBOL(tcp_memory_allocated); 293 294/* 295 * Current number of TCP sockets. 296 */ 297struct percpu_counter tcp_sockets_allocated; 298EXPORT_SYMBOL(tcp_sockets_allocated); 299 300/* 301 * TCP splice context 302 */ 303struct tcp_splice_state { 304 struct pipe_inode_info *pipe; 305 size_t len; 306 unsigned int flags; 307}; 308 309/* 310 * Pressure flag: try to collapse. 311 * Technical note: it is used by multiple contexts non atomically. 312 * All the __sk_mem_schedule() is of this nature: accounting 313 * is strict, actions are advisory and have some latency. 314 */ 315int tcp_memory_pressure __read_mostly; 316 317EXPORT_SYMBOL(tcp_memory_pressure); 318 319void tcp_enter_memory_pressure(struct sock *sk) 320{ 321 if (!tcp_memory_pressure) { 322 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 323 tcp_memory_pressure = 1; 324 } 325} 326 327EXPORT_SYMBOL(tcp_enter_memory_pressure); 328 329/* 330 * Wait for a TCP event. 331 * 332 * Note that we don't need to lock the socket, as the upper poll layers 333 * take care of normal races (between the test and the event) and we don't 334 * go look at any of the socket buffers directly. 335 */ 336unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 337{ 338 unsigned int mask; 339 struct sock *sk = sock->sk; 340 struct tcp_sock *tp = tcp_sk(sk); 341 342 poll_wait(file, sk->sk_sleep, wait); 343 if (sk->sk_state == TCP_LISTEN) 344 return inet_csk_listen_poll(sk); 345 346 /* Socket is not locked. We are protected from async events 347 * by poll logic and correct handling of state changes 348 * made by other threads is impossible in any case. 349 */ 350 351 mask = 0; 352 if (sk->sk_err) 353 mask = POLLERR; 354 355 /* 356 * POLLHUP is certainly not done right. But poll() doesn't 357 * have a notion of HUP in just one direction, and for a 358 * socket the read side is more interesting. 359 * 360 * Some poll() documentation says that POLLHUP is incompatible 361 * with the POLLOUT/POLLWR flags, so somebody should check this 362 * all. But careful, it tends to be safer to return too many 363 * bits than too few, and you can easily break real applications 364 * if you don't tell them that something has hung up! 365 * 366 * Check-me. 367 * 368 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 369 * our fs/select.c). It means that after we received EOF, 370 * poll always returns immediately, making impossible poll() on write() 371 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 372 * if and only if shutdown has been made in both directions. 373 * Actually, it is interesting to look how Solaris and DUX 374 * solve this dilemma. I would prefer, if POLLHUP were maskable, 375 * then we could set it on SND_SHUTDOWN. BTW examples given 376 * in Stevens' books assume exactly this behaviour, it explains 377 * why POLLHUP is incompatible with POLLOUT. --ANK 378 * 379 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 380 * blocking on fresh not-connected or disconnected socket. --ANK 381 */ 382 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 383 mask |= POLLHUP; 384 if (sk->sk_shutdown & RCV_SHUTDOWN) 385 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 386 387 /* Connected? */ 388 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 389 int target = sock_rcvlowat(sk, 0, INT_MAX); 390 391 if (tp->urg_seq == tp->copied_seq && 392 !sock_flag(sk, SOCK_URGINLINE) && 393 tp->urg_data) 394 target--; 395 396 /* Potential race condition. If read of tp below will 397 * escape above sk->sk_state, we can be illegally awaken 398 * in SYN_* states. */ 399 if (tp->rcv_nxt - tp->copied_seq >= target) 400 mask |= POLLIN | POLLRDNORM; 401 402 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 403 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 404 mask |= POLLOUT | POLLWRNORM; 405 } else { /* send SIGIO later */ 406 set_bit(SOCK_ASYNC_NOSPACE, 407 &sk->sk_socket->flags); 408 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 409 410 /* Race breaker. If space is freed after 411 * wspace test but before the flags are set, 412 * IO signal will be lost. 413 */ 414 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 415 mask |= POLLOUT | POLLWRNORM; 416 } 417 } 418 419 if (tp->urg_data & TCP_URG_VALID) 420 mask |= POLLPRI; 421 } 422 return mask; 423} 424 425int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 426{ 427 struct tcp_sock *tp = tcp_sk(sk); 428 int answ; 429 430 switch (cmd) { 431 case SIOCINQ: 432 if (sk->sk_state == TCP_LISTEN) 433 return -EINVAL; 434 435 lock_sock(sk); 436 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 437 answ = 0; 438 else if (sock_flag(sk, SOCK_URGINLINE) || 439 !tp->urg_data || 440 before(tp->urg_seq, tp->copied_seq) || 441 !before(tp->urg_seq, tp->rcv_nxt)) { 442 answ = tp->rcv_nxt - tp->copied_seq; 443 444 /* Subtract 1, if FIN is in queue. */ 445 if (answ && !skb_queue_empty(&sk->sk_receive_queue)) 446 answ -= 447 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin; 448 } else 449 answ = tp->urg_seq - tp->copied_seq; 450 release_sock(sk); 451 break; 452 case SIOCATMARK: 453 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 454 break; 455 case SIOCOUTQ: 456 if (sk->sk_state == TCP_LISTEN) 457 return -EINVAL; 458 459 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 460 answ = 0; 461 else 462 answ = tp->write_seq - tp->snd_una; 463 break; 464 default: 465 return -ENOIOCTLCMD; 466 } 467 468 return put_user(answ, (int __user *)arg); 469} 470 471static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 472{ 473 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; 474 tp->pushed_seq = tp->write_seq; 475} 476 477static inline int forced_push(struct tcp_sock *tp) 478{ 479 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 480} 481 482static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 483{ 484 struct tcp_sock *tp = tcp_sk(sk); 485 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 486 487 skb->csum = 0; 488 tcb->seq = tcb->end_seq = tp->write_seq; 489 tcb->flags = TCPCB_FLAG_ACK; 490 tcb->sacked = 0; 491 skb_header_release(skb); 492 tcp_add_write_queue_tail(sk, skb); 493 sk->sk_wmem_queued += skb->truesize; 494 sk_mem_charge(sk, skb->truesize); 495 if (tp->nonagle & TCP_NAGLE_PUSH) 496 tp->nonagle &= ~TCP_NAGLE_PUSH; 497} 498 499static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 500 struct sk_buff *skb) 501{ 502 if (flags & MSG_OOB) 503 tp->snd_up = tp->write_seq; 504} 505 506static inline void tcp_push(struct sock *sk, int flags, int mss_now, 507 int nonagle) 508{ 509 struct tcp_sock *tp = tcp_sk(sk); 510 511 if (tcp_send_head(sk)) { 512 struct sk_buff *skb = tcp_write_queue_tail(sk); 513 if (!(flags & MSG_MORE) || forced_push(tp)) 514 tcp_mark_push(tp, skb); 515 tcp_mark_urg(tp, flags, skb); 516 __tcp_push_pending_frames(sk, mss_now, 517 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 518 } 519} 520 521static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 522 unsigned int offset, size_t len) 523{ 524 struct tcp_splice_state *tss = rd_desc->arg.data; 525 int ret; 526 527 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 528 tss->flags); 529 if (ret > 0) 530 rd_desc->count -= ret; 531 return ret; 532} 533 534static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 535{ 536 /* Store TCP splice context information in read_descriptor_t. */ 537 read_descriptor_t rd_desc = { 538 .arg.data = tss, 539 .count = tss->len, 540 }; 541 542 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 543} 544 545/** 546 * tcp_splice_read - splice data from TCP socket to a pipe 547 * @sock: socket to splice from 548 * @ppos: position (not valid) 549 * @pipe: pipe to splice to 550 * @len: number of bytes to splice 551 * @flags: splice modifier flags 552 * 553 * Description: 554 * Will read pages from given socket and fill them into a pipe. 555 * 556 **/ 557ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 558 struct pipe_inode_info *pipe, size_t len, 559 unsigned int flags) 560{ 561 struct sock *sk = sock->sk; 562 struct tcp_splice_state tss = { 563 .pipe = pipe, 564 .len = len, 565 .flags = flags, 566 }; 567 long timeo; 568 ssize_t spliced; 569 int ret; 570 571 /* 572 * We can't seek on a socket input 573 */ 574 if (unlikely(*ppos)) 575 return -ESPIPE; 576 577 ret = spliced = 0; 578 579 lock_sock(sk); 580 581 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK); 582 while (tss.len) { 583 ret = __tcp_splice_read(sk, &tss); 584 if (ret < 0) 585 break; 586 else if (!ret) { 587 if (spliced) 588 break; 589 if (sock_flag(sk, SOCK_DONE)) 590 break; 591 if (sk->sk_err) { 592 ret = sock_error(sk); 593 break; 594 } 595 if (sk->sk_shutdown & RCV_SHUTDOWN) 596 break; 597 if (sk->sk_state == TCP_CLOSE) { 598 /* 599 * This occurs when user tries to read 600 * from never connected socket. 601 */ 602 if (!sock_flag(sk, SOCK_DONE)) 603 ret = -ENOTCONN; 604 break; 605 } 606 if (!timeo) { 607 ret = -EAGAIN; 608 break; 609 } 610 sk_wait_data(sk, &timeo); 611 if (signal_pending(current)) { 612 ret = sock_intr_errno(timeo); 613 break; 614 } 615 continue; 616 } 617 tss.len -= ret; 618 spliced += ret; 619 620 if (!timeo) 621 break; 622 release_sock(sk); 623 lock_sock(sk); 624 625 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 626 (sk->sk_shutdown & RCV_SHUTDOWN) || 627 signal_pending(current)) 628 break; 629 } 630 631 release_sock(sk); 632 633 if (spliced) 634 return spliced; 635 636 return ret; 637} 638 639struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 640{ 641 struct sk_buff *skb; 642 643 /* The TCP header must be at least 32-bit aligned. */ 644 size = ALIGN(size, 4); 645 646 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 647 if (skb) { 648 if (sk_wmem_schedule(sk, skb->truesize)) { 649 /* 650 * Make sure that we have exactly size bytes 651 * available to the caller, no more, no less. 652 */ 653 skb_reserve(skb, skb_tailroom(skb) - size); 654 return skb; 655 } 656 __kfree_skb(skb); 657 } else { 658 sk->sk_prot->enter_memory_pressure(sk); 659 sk_stream_moderate_sndbuf(sk); 660 } 661 return NULL; 662} 663 664static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 665 size_t psize, int flags) 666{ 667 struct tcp_sock *tp = tcp_sk(sk); 668 int mss_now, size_goal; 669 int err; 670 ssize_t copied; 671 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 672 673 /* Wait for a connection to finish. */ 674 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 675 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 676 goto out_err; 677 678 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 679 680 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 681 size_goal = tp->xmit_size_goal; 682 copied = 0; 683 684 err = -EPIPE; 685 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 686 goto do_error; 687 688 while (psize > 0) { 689 struct sk_buff *skb = tcp_write_queue_tail(sk); 690 struct page *page = pages[poffset / PAGE_SIZE]; 691 int copy, i, can_coalesce; 692 int offset = poffset % PAGE_SIZE; 693 int size = min_t(size_t, psize, PAGE_SIZE - offset); 694 695 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 696new_segment: 697 if (!sk_stream_memory_free(sk)) 698 goto wait_for_sndbuf; 699 700 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 701 if (!skb) 702 goto wait_for_memory; 703 704 skb_entail(sk, skb); 705 copy = size_goal; 706 } 707 708 if (copy > size) 709 copy = size; 710 711 i = skb_shinfo(skb)->nr_frags; 712 can_coalesce = skb_can_coalesce(skb, i, page, offset); 713 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 714 tcp_mark_push(tp, skb); 715 goto new_segment; 716 } 717 if (!sk_wmem_schedule(sk, copy)) 718 goto wait_for_memory; 719 720 if (can_coalesce) { 721 skb_shinfo(skb)->frags[i - 1].size += copy; 722 } else { 723 get_page(page); 724 skb_fill_page_desc(skb, i, page, offset, copy); 725 } 726 727 skb->len += copy; 728 skb->data_len += copy; 729 skb->truesize += copy; 730 sk->sk_wmem_queued += copy; 731 sk_mem_charge(sk, copy); 732 skb->ip_summed = CHECKSUM_PARTIAL; 733 tp->write_seq += copy; 734 TCP_SKB_CB(skb)->end_seq += copy; 735 skb_shinfo(skb)->gso_segs = 0; 736 737 if (!copied) 738 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 739 740 copied += copy; 741 poffset += copy; 742 if (!(psize -= copy)) 743 goto out; 744 745 if (skb->len < size_goal || (flags & MSG_OOB)) 746 continue; 747 748 if (forced_push(tp)) { 749 tcp_mark_push(tp, skb); 750 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 751 } else if (skb == tcp_send_head(sk)) 752 tcp_push_one(sk, mss_now); 753 continue; 754 755wait_for_sndbuf: 756 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 757wait_for_memory: 758 if (copied) 759 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 760 761 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 762 goto do_error; 763 764 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 765 size_goal = tp->xmit_size_goal; 766 } 767 768out: 769 if (copied) 770 tcp_push(sk, flags, mss_now, tp->nonagle); 771 return copied; 772 773do_error: 774 if (copied) 775 goto out; 776out_err: 777 return sk_stream_error(sk, flags, err); 778} 779 780ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, 781 size_t size, int flags) 782{ 783 ssize_t res; 784 struct sock *sk = sock->sk; 785 786 if (!(sk->sk_route_caps & NETIF_F_SG) || 787 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 788 return sock_no_sendpage(sock, page, offset, size, flags); 789 790 lock_sock(sk); 791 TCP_CHECK_TIMER(sk); 792 res = do_tcp_sendpages(sk, &page, offset, size, flags); 793 TCP_CHECK_TIMER(sk); 794 release_sock(sk); 795 return res; 796} 797 798#define TCP_PAGE(sk) (sk->sk_sndmsg_page) 799#define TCP_OFF(sk) (sk->sk_sndmsg_off) 800 801static inline int select_size(struct sock *sk) 802{ 803 struct tcp_sock *tp = tcp_sk(sk); 804 int tmp = tp->mss_cache; 805 806 if (sk->sk_route_caps & NETIF_F_SG) { 807 if (sk_can_gso(sk)) 808 tmp = 0; 809 else { 810 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 811 812 if (tmp >= pgbreak && 813 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 814 tmp = pgbreak; 815 } 816 } 817 818 return tmp; 819} 820 821int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 822 size_t size) 823{ 824 struct sock *sk = sock->sk; 825 struct iovec *iov; 826 struct tcp_sock *tp = tcp_sk(sk); 827 struct sk_buff *skb; 828 int iovlen, flags; 829 int mss_now, size_goal; 830 int err, copied; 831 long timeo; 832 833 lock_sock(sk); 834 TCP_CHECK_TIMER(sk); 835 836 flags = msg->msg_flags; 837 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 838 839 /* Wait for a connection to finish. */ 840 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 841 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 842 goto out_err; 843 844 /* This should be in poll */ 845 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 846 847 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 848 size_goal = tp->xmit_size_goal; 849 850 /* Ok commence sending. */ 851 iovlen = msg->msg_iovlen; 852 iov = msg->msg_iov; 853 copied = 0; 854 855 err = -EPIPE; 856 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 857 goto do_error; 858 859 while (--iovlen >= 0) { 860 int seglen = iov->iov_len; 861 unsigned char __user *from = iov->iov_base; 862 863 iov++; 864 865 while (seglen > 0) { 866 int copy; 867 868 skb = tcp_write_queue_tail(sk); 869 870 if (!tcp_send_head(sk) || 871 (copy = size_goal - skb->len) <= 0) { 872 873new_segment: 874 /* Allocate new segment. If the interface is SG, 875 * allocate skb fitting to single page. 876 */ 877 if (!sk_stream_memory_free(sk)) 878 goto wait_for_sndbuf; 879 880 skb = sk_stream_alloc_skb(sk, select_size(sk), 881 sk->sk_allocation); 882 if (!skb) 883 goto wait_for_memory; 884 885 /* 886 * Check whether we can use HW checksum. 887 */ 888 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 889 skb->ip_summed = CHECKSUM_PARTIAL; 890 891 skb_entail(sk, skb); 892 copy = size_goal; 893 } 894 895 /* Try to append data to the end of skb. */ 896 if (copy > seglen) 897 copy = seglen; 898 899 /* Where to copy to? */ 900 if (skb_tailroom(skb) > 0) { 901 /* We have some space in skb head. Superb! */ 902 if (copy > skb_tailroom(skb)) 903 copy = skb_tailroom(skb); 904 if ((err = skb_add_data(skb, from, copy)) != 0) 905 goto do_fault; 906 } else { 907 int merge = 0; 908 int i = skb_shinfo(skb)->nr_frags; 909 struct page *page = TCP_PAGE(sk); 910 int off = TCP_OFF(sk); 911 912 if (skb_can_coalesce(skb, i, page, off) && 913 off != PAGE_SIZE) { 914 /* We can extend the last page 915 * fragment. */ 916 merge = 1; 917 } else if (i == MAX_SKB_FRAGS || 918 (!i && 919 !(sk->sk_route_caps & NETIF_F_SG))) { 920 /* Need to add new fragment and cannot 921 * do this because interface is non-SG, 922 * or because all the page slots are 923 * busy. */ 924 tcp_mark_push(tp, skb); 925 goto new_segment; 926 } else if (page) { 927 if (off == PAGE_SIZE) { 928 put_page(page); 929 TCP_PAGE(sk) = page = NULL; 930 off = 0; 931 } 932 } else 933 off = 0; 934 935 if (copy > PAGE_SIZE - off) 936 copy = PAGE_SIZE - off; 937 938 if (!sk_wmem_schedule(sk, copy)) 939 goto wait_for_memory; 940 941 if (!page) { 942 /* Allocate new cache page. */ 943 if (!(page = sk_stream_alloc_page(sk))) 944 goto wait_for_memory; 945 } 946 947 /* Time to copy data. We are close to 948 * the end! */ 949 err = skb_copy_to_page(sk, from, skb, page, 950 off, copy); 951 if (err) { 952 /* If this page was new, give it to the 953 * socket so it does not get leaked. 954 */ 955 if (!TCP_PAGE(sk)) { 956 TCP_PAGE(sk) = page; 957 TCP_OFF(sk) = 0; 958 } 959 goto do_error; 960 } 961 962 /* Update the skb. */ 963 if (merge) { 964 skb_shinfo(skb)->frags[i - 1].size += 965 copy; 966 } else { 967 skb_fill_page_desc(skb, i, page, off, copy); 968 if (TCP_PAGE(sk)) { 969 get_page(page); 970 } else if (off + copy < PAGE_SIZE) { 971 get_page(page); 972 TCP_PAGE(sk) = page; 973 } 974 } 975 976 TCP_OFF(sk) = off + copy; 977 } 978 979 if (!copied) 980 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 981 982 tp->write_seq += copy; 983 TCP_SKB_CB(skb)->end_seq += copy; 984 skb_shinfo(skb)->gso_segs = 0; 985 986 from += copy; 987 copied += copy; 988 if ((seglen -= copy) == 0 && iovlen == 0) 989 goto out; 990 991 if (skb->len < size_goal || (flags & MSG_OOB)) 992 continue; 993 994 if (forced_push(tp)) { 995 tcp_mark_push(tp, skb); 996 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 997 } else if (skb == tcp_send_head(sk)) 998 tcp_push_one(sk, mss_now); 999 continue; 1000 1001wait_for_sndbuf: 1002 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1003wait_for_memory: 1004 if (copied) 1005 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 1006 1007 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1008 goto do_error; 1009 1010 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 1011 size_goal = tp->xmit_size_goal; 1012 } 1013 } 1014 1015out: 1016 if (copied) 1017 tcp_push(sk, flags, mss_now, tp->nonagle); 1018 TCP_CHECK_TIMER(sk); 1019 release_sock(sk); 1020 return copied; 1021 1022do_fault: 1023 if (!skb->len) { 1024 tcp_unlink_write_queue(skb, sk); 1025 /* It is the one place in all of TCP, except connection 1026 * reset, where we can be unlinking the send_head. 1027 */ 1028 tcp_check_send_head(sk, skb); 1029 sk_wmem_free_skb(sk, skb); 1030 } 1031 1032do_error: 1033 if (copied) 1034 goto out; 1035out_err: 1036 err = sk_stream_error(sk, flags, err); 1037 TCP_CHECK_TIMER(sk); 1038 release_sock(sk); 1039 return err; 1040} 1041 1042/* 1043 * Handle reading urgent data. BSD has very simple semantics for 1044 * this, no blocking and very strange errors 8) 1045 */ 1046 1047static int tcp_recv_urg(struct sock *sk, long timeo, 1048 struct msghdr *msg, int len, int flags, 1049 int *addr_len) 1050{ 1051 struct tcp_sock *tp = tcp_sk(sk); 1052 1053 /* No URG data to read. */ 1054 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1055 tp->urg_data == TCP_URG_READ) 1056 return -EINVAL; /* Yes this is right ! */ 1057 1058 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1059 return -ENOTCONN; 1060 1061 if (tp->urg_data & TCP_URG_VALID) { 1062 int err = 0; 1063 char c = tp->urg_data; 1064 1065 if (!(flags & MSG_PEEK)) 1066 tp->urg_data = TCP_URG_READ; 1067 1068 /* Read urgent data. */ 1069 msg->msg_flags |= MSG_OOB; 1070 1071 if (len > 0) { 1072 if (!(flags & MSG_TRUNC)) 1073 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1074 len = 1; 1075 } else 1076 msg->msg_flags |= MSG_TRUNC; 1077 1078 return err ? -EFAULT : len; 1079 } 1080 1081 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1082 return 0; 1083 1084 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1085 * the available implementations agree in this case: 1086 * this call should never block, independent of the 1087 * blocking state of the socket. 1088 * Mike <pall@rz.uni-karlsruhe.de> 1089 */ 1090 return -EAGAIN; 1091} 1092 1093/* Clean up the receive buffer for full frames taken by the user, 1094 * then send an ACK if necessary. COPIED is the number of bytes 1095 * tcp_recvmsg has given to the user so far, it speeds up the 1096 * calculation of whether or not we must ACK for the sake of 1097 * a window update. 1098 */ 1099void tcp_cleanup_rbuf(struct sock *sk, int copied) 1100{ 1101 struct tcp_sock *tp = tcp_sk(sk); 1102 int time_to_ack = 0; 1103 1104#if TCP_DEBUG 1105 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1106 1107 WARN_ON(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)); 1108#endif 1109 1110 if (inet_csk_ack_scheduled(sk)) { 1111 const struct inet_connection_sock *icsk = inet_csk(sk); 1112 /* Delayed ACKs frequently hit locked sockets during bulk 1113 * receive. */ 1114 if (icsk->icsk_ack.blocked || 1115 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1116 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1117 /* 1118 * If this read emptied read buffer, we send ACK, if 1119 * connection is not bidirectional, user drained 1120 * receive buffer and there was a small segment 1121 * in queue. 1122 */ 1123 (copied > 0 && 1124 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1125 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1126 !icsk->icsk_ack.pingpong)) && 1127 !atomic_read(&sk->sk_rmem_alloc))) 1128 time_to_ack = 1; 1129 } 1130 1131 /* We send an ACK if we can now advertise a non-zero window 1132 * which has been raised "significantly". 1133 * 1134 * Even if window raised up to infinity, do not send window open ACK 1135 * in states, where we will not receive more. It is useless. 1136 */ 1137 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1138 __u32 rcv_window_now = tcp_receive_window(tp); 1139 1140 /* Optimize, __tcp_select_window() is not cheap. */ 1141 if (2*rcv_window_now <= tp->window_clamp) { 1142 __u32 new_window = __tcp_select_window(sk); 1143 1144 /* Send ACK now, if this read freed lots of space 1145 * in our buffer. Certainly, new_window is new window. 1146 * We can advertise it now, if it is not less than current one. 1147 * "Lots" means "at least twice" here. 1148 */ 1149 if (new_window && new_window >= 2 * rcv_window_now) 1150 time_to_ack = 1; 1151 } 1152 } 1153 if (time_to_ack) 1154 tcp_send_ack(sk); 1155} 1156 1157static void tcp_prequeue_process(struct sock *sk) 1158{ 1159 struct sk_buff *skb; 1160 struct tcp_sock *tp = tcp_sk(sk); 1161 1162 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1163 1164 /* RX process wants to run with disabled BHs, though it is not 1165 * necessary */ 1166 local_bh_disable(); 1167 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1168 sk_backlog_rcv(sk, skb); 1169 local_bh_enable(); 1170 1171 /* Clear memory counter. */ 1172 tp->ucopy.memory = 0; 1173} 1174 1175static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1176{ 1177 struct sk_buff *skb; 1178 u32 offset; 1179 1180 skb_queue_walk(&sk->sk_receive_queue, skb) { 1181 offset = seq - TCP_SKB_CB(skb)->seq; 1182 if (tcp_hdr(skb)->syn) 1183 offset--; 1184 if (offset < skb->len || tcp_hdr(skb)->fin) { 1185 *off = offset; 1186 return skb; 1187 } 1188 } 1189 return NULL; 1190} 1191 1192/* 1193 * This routine provides an alternative to tcp_recvmsg() for routines 1194 * that would like to handle copying from skbuffs directly in 'sendfile' 1195 * fashion. 1196 * Note: 1197 * - It is assumed that the socket was locked by the caller. 1198 * - The routine does not block. 1199 * - At present, there is no support for reading OOB data 1200 * or for 'peeking' the socket using this routine 1201 * (although both would be easy to implement). 1202 */ 1203int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1204 sk_read_actor_t recv_actor) 1205{ 1206 struct sk_buff *skb; 1207 struct tcp_sock *tp = tcp_sk(sk); 1208 u32 seq = tp->copied_seq; 1209 u32 offset; 1210 int copied = 0; 1211 1212 if (sk->sk_state == TCP_LISTEN) 1213 return -ENOTCONN; 1214 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1215 if (offset < skb->len) { 1216 int used; 1217 size_t len; 1218 1219 len = skb->len - offset; 1220 /* Stop reading if we hit a patch of urgent data */ 1221 if (tp->urg_data) { 1222 u32 urg_offset = tp->urg_seq - seq; 1223 if (urg_offset < len) 1224 len = urg_offset; 1225 if (!len) 1226 break; 1227 } 1228 used = recv_actor(desc, skb, offset, len); 1229 if (used < 0) { 1230 if (!copied) 1231 copied = used; 1232 break; 1233 } else if (used <= len) { 1234 seq += used; 1235 copied += used; 1236 offset += used; 1237 } 1238 /* 1239 * If recv_actor drops the lock (e.g. TCP splice 1240 * receive) the skb pointer might be invalid when 1241 * getting here: tcp_collapse might have deleted it 1242 * while aggregating skbs from the socket queue. 1243 */ 1244 skb = tcp_recv_skb(sk, seq-1, &offset); 1245 if (!skb || (offset+1 != skb->len)) 1246 break; 1247 } 1248 if (tcp_hdr(skb)->fin) { 1249 sk_eat_skb(sk, skb, 0); 1250 ++seq; 1251 break; 1252 } 1253 sk_eat_skb(sk, skb, 0); 1254 if (!desc->count) 1255 break; 1256 } 1257 tp->copied_seq = seq; 1258 1259 tcp_rcv_space_adjust(sk); 1260 1261 /* Clean up data we have read: This will do ACK frames. */ 1262 if (copied > 0) 1263 tcp_cleanup_rbuf(sk, copied); 1264 return copied; 1265} 1266 1267/* 1268 * This routine copies from a sock struct into the user buffer. 1269 * 1270 * Technical note: in 2.3 we work on _locked_ socket, so that 1271 * tricks with *seq access order and skb->users are not required. 1272 * Probably, code can be easily improved even more. 1273 */ 1274 1275int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1276 size_t len, int nonblock, int flags, int *addr_len) 1277{ 1278 struct tcp_sock *tp = tcp_sk(sk); 1279 int copied = 0; 1280 u32 peek_seq; 1281 u32 *seq; 1282 unsigned long used; 1283 int err; 1284 int target; /* Read at least this many bytes */ 1285 long timeo; 1286 struct task_struct *user_recv = NULL; 1287 int copied_early = 0; 1288 struct sk_buff *skb; 1289 1290 lock_sock(sk); 1291 1292 TCP_CHECK_TIMER(sk); 1293 1294 err = -ENOTCONN; 1295 if (sk->sk_state == TCP_LISTEN) 1296 goto out; 1297 1298 timeo = sock_rcvtimeo(sk, nonblock); 1299 1300 /* Urgent data needs to be handled specially. */ 1301 if (flags & MSG_OOB) 1302 goto recv_urg; 1303 1304 seq = &tp->copied_seq; 1305 if (flags & MSG_PEEK) { 1306 peek_seq = tp->copied_seq; 1307 seq = &peek_seq; 1308 } 1309 1310 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1311 1312#ifdef CONFIG_NET_DMA 1313 tp->ucopy.dma_chan = NULL; 1314 preempt_disable(); 1315 skb = skb_peek_tail(&sk->sk_receive_queue); 1316 { 1317 int available = 0; 1318 1319 if (skb) 1320 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1321 if ((available < target) && 1322 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1323 !sysctl_tcp_low_latency && 1324 dma_find_channel(DMA_MEMCPY)) { 1325 preempt_enable_no_resched(); 1326 tp->ucopy.pinned_list = 1327 dma_pin_iovec_pages(msg->msg_iov, len); 1328 } else { 1329 preempt_enable_no_resched(); 1330 } 1331 } 1332#endif 1333 1334 do { 1335 u32 offset; 1336 1337 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1338 if (tp->urg_data && tp->urg_seq == *seq) { 1339 if (copied) 1340 break; 1341 if (signal_pending(current)) { 1342 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1343 break; 1344 } 1345 } 1346 1347 /* Next get a buffer. */ 1348 1349 skb = skb_peek(&sk->sk_receive_queue); 1350 do { 1351 if (!skb) 1352 break; 1353 1354 /* Now that we have two receive queues this 1355 * shouldn't happen. 1356 */ 1357 if (before(*seq, TCP_SKB_CB(skb)->seq)) { 1358 printk(KERN_INFO "recvmsg bug: copied %X " 1359 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq); 1360 break; 1361 } 1362 offset = *seq - TCP_SKB_CB(skb)->seq; 1363 if (tcp_hdr(skb)->syn) 1364 offset--; 1365 if (offset < skb->len) 1366 goto found_ok_skb; 1367 if (tcp_hdr(skb)->fin) 1368 goto found_fin_ok; 1369 WARN_ON(!(flags & MSG_PEEK)); 1370 skb = skb->next; 1371 } while (skb != (struct sk_buff *)&sk->sk_receive_queue); 1372 1373 /* Well, if we have backlog, try to process it now yet. */ 1374 1375 if (copied >= target && !sk->sk_backlog.tail) 1376 break; 1377 1378 if (copied) { 1379 if (sk->sk_err || 1380 sk->sk_state == TCP_CLOSE || 1381 (sk->sk_shutdown & RCV_SHUTDOWN) || 1382 !timeo || 1383 signal_pending(current)) 1384 break; 1385 } else { 1386 if (sock_flag(sk, SOCK_DONE)) 1387 break; 1388 1389 if (sk->sk_err) { 1390 copied = sock_error(sk); 1391 break; 1392 } 1393 1394 if (sk->sk_shutdown & RCV_SHUTDOWN) 1395 break; 1396 1397 if (sk->sk_state == TCP_CLOSE) { 1398 if (!sock_flag(sk, SOCK_DONE)) { 1399 /* This occurs when user tries to read 1400 * from never connected socket. 1401 */ 1402 copied = -ENOTCONN; 1403 break; 1404 } 1405 break; 1406 } 1407 1408 if (!timeo) { 1409 copied = -EAGAIN; 1410 break; 1411 } 1412 1413 if (signal_pending(current)) { 1414 copied = sock_intr_errno(timeo); 1415 break; 1416 } 1417 } 1418 1419 tcp_cleanup_rbuf(sk, copied); 1420 1421 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1422 /* Install new reader */ 1423 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1424 user_recv = current; 1425 tp->ucopy.task = user_recv; 1426 tp->ucopy.iov = msg->msg_iov; 1427 } 1428 1429 tp->ucopy.len = len; 1430 1431 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1432 !(flags & (MSG_PEEK | MSG_TRUNC))); 1433 1434 /* Ugly... If prequeue is not empty, we have to 1435 * process it before releasing socket, otherwise 1436 * order will be broken at second iteration. 1437 * More elegant solution is required!!! 1438 * 1439 * Look: we have the following (pseudo)queues: 1440 * 1441 * 1. packets in flight 1442 * 2. backlog 1443 * 3. prequeue 1444 * 4. receive_queue 1445 * 1446 * Each queue can be processed only if the next ones 1447 * are empty. At this point we have empty receive_queue. 1448 * But prequeue _can_ be not empty after 2nd iteration, 1449 * when we jumped to start of loop because backlog 1450 * processing added something to receive_queue. 1451 * We cannot release_sock(), because backlog contains 1452 * packets arrived _after_ prequeued ones. 1453 * 1454 * Shortly, algorithm is clear --- to process all 1455 * the queues in order. We could make it more directly, 1456 * requeueing packets from backlog to prequeue, if 1457 * is not empty. It is more elegant, but eats cycles, 1458 * unfortunately. 1459 */ 1460 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1461 goto do_prequeue; 1462 1463 /* __ Set realtime policy in scheduler __ */ 1464 } 1465 1466 if (copied >= target) { 1467 /* Do not sleep, just process backlog. */ 1468 release_sock(sk); 1469 lock_sock(sk); 1470 } else 1471 sk_wait_data(sk, &timeo); 1472 1473#ifdef CONFIG_NET_DMA 1474 tp->ucopy.wakeup = 0; 1475#endif 1476 1477 if (user_recv) { 1478 int chunk; 1479 1480 /* __ Restore normal policy in scheduler __ */ 1481 1482 if ((chunk = len - tp->ucopy.len) != 0) { 1483 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1484 len -= chunk; 1485 copied += chunk; 1486 } 1487 1488 if (tp->rcv_nxt == tp->copied_seq && 1489 !skb_queue_empty(&tp->ucopy.prequeue)) { 1490do_prequeue: 1491 tcp_prequeue_process(sk); 1492 1493 if ((chunk = len - tp->ucopy.len) != 0) { 1494 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1495 len -= chunk; 1496 copied += chunk; 1497 } 1498 } 1499 } 1500 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) { 1501 if (net_ratelimit()) 1502 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1503 current->comm, task_pid_nr(current)); 1504 peek_seq = tp->copied_seq; 1505 } 1506 continue; 1507 1508 found_ok_skb: 1509 /* Ok so how much can we use? */ 1510 used = skb->len - offset; 1511 if (len < used) 1512 used = len; 1513 1514 /* Do we have urgent data here? */ 1515 if (tp->urg_data) { 1516 u32 urg_offset = tp->urg_seq - *seq; 1517 if (urg_offset < used) { 1518 if (!urg_offset) { 1519 if (!sock_flag(sk, SOCK_URGINLINE)) { 1520 ++*seq; 1521 offset++; 1522 used--; 1523 if (!used) 1524 goto skip_copy; 1525 } 1526 } else 1527 used = urg_offset; 1528 } 1529 } 1530 1531 if (!(flags & MSG_TRUNC)) { 1532#ifdef CONFIG_NET_DMA 1533 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1534 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY); 1535 1536 if (tp->ucopy.dma_chan) { 1537 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1538 tp->ucopy.dma_chan, skb, offset, 1539 msg->msg_iov, used, 1540 tp->ucopy.pinned_list); 1541 1542 if (tp->ucopy.dma_cookie < 0) { 1543 1544 printk(KERN_ALERT "dma_cookie < 0\n"); 1545 1546 /* Exception. Bailout! */ 1547 if (!copied) 1548 copied = -EFAULT; 1549 break; 1550 } 1551 if ((offset + used) == skb->len) 1552 copied_early = 1; 1553 1554 } else 1555#endif 1556 { 1557 err = skb_copy_datagram_iovec(skb, offset, 1558 msg->msg_iov, used); 1559 if (err) { 1560 /* Exception. Bailout! */ 1561 if (!copied) 1562 copied = -EFAULT; 1563 break; 1564 } 1565 } 1566 } 1567 1568 *seq += used; 1569 copied += used; 1570 len -= used; 1571 1572 tcp_rcv_space_adjust(sk); 1573 1574skip_copy: 1575 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1576 tp->urg_data = 0; 1577 tcp_fast_path_check(sk); 1578 } 1579 if (used + offset < skb->len) 1580 continue; 1581 1582 if (tcp_hdr(skb)->fin) 1583 goto found_fin_ok; 1584 if (!(flags & MSG_PEEK)) { 1585 sk_eat_skb(sk, skb, copied_early); 1586 copied_early = 0; 1587 } 1588 continue; 1589 1590 found_fin_ok: 1591 /* Process the FIN. */ 1592 ++*seq; 1593 if (!(flags & MSG_PEEK)) { 1594 sk_eat_skb(sk, skb, copied_early); 1595 copied_early = 0; 1596 } 1597 break; 1598 } while (len > 0); 1599 1600 if (user_recv) { 1601 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1602 int chunk; 1603 1604 tp->ucopy.len = copied > 0 ? len : 0; 1605 1606 tcp_prequeue_process(sk); 1607 1608 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1609 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1610 len -= chunk; 1611 copied += chunk; 1612 } 1613 } 1614 1615 tp->ucopy.task = NULL; 1616 tp->ucopy.len = 0; 1617 } 1618 1619#ifdef CONFIG_NET_DMA 1620 if (tp->ucopy.dma_chan) { 1621 dma_cookie_t done, used; 1622 1623 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1624 1625 while (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1626 tp->ucopy.dma_cookie, &done, 1627 &used) == DMA_IN_PROGRESS) { 1628 /* do partial cleanup of sk_async_wait_queue */ 1629 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1630 (dma_async_is_complete(skb->dma_cookie, done, 1631 used) == DMA_SUCCESS)) { 1632 __skb_dequeue(&sk->sk_async_wait_queue); 1633 kfree_skb(skb); 1634 } 1635 } 1636 1637 /* Safe to free early-copied skbs now */ 1638 __skb_queue_purge(&sk->sk_async_wait_queue); 1639 tp->ucopy.dma_chan = NULL; 1640 } 1641 if (tp->ucopy.pinned_list) { 1642 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1643 tp->ucopy.pinned_list = NULL; 1644 } 1645#endif 1646 1647 /* According to UNIX98, msg_name/msg_namelen are ignored 1648 * on connected socket. I was just happy when found this 8) --ANK 1649 */ 1650 1651 /* Clean up data we have read: This will do ACK frames. */ 1652 tcp_cleanup_rbuf(sk, copied); 1653 1654 TCP_CHECK_TIMER(sk); 1655 release_sock(sk); 1656 return copied; 1657 1658out: 1659 TCP_CHECK_TIMER(sk); 1660 release_sock(sk); 1661 return err; 1662 1663recv_urg: 1664 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); 1665 goto out; 1666} 1667 1668void tcp_set_state(struct sock *sk, int state) 1669{ 1670 int oldstate = sk->sk_state; 1671 1672 switch (state) { 1673 case TCP_ESTABLISHED: 1674 if (oldstate != TCP_ESTABLISHED) 1675 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1676 break; 1677 1678 case TCP_CLOSE: 1679 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1680 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1681 1682 sk->sk_prot->unhash(sk); 1683 if (inet_csk(sk)->icsk_bind_hash && 1684 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1685 inet_put_port(sk); 1686 /* fall through */ 1687 default: 1688 if (oldstate == TCP_ESTABLISHED) 1689 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1690 } 1691 1692 /* Change state AFTER socket is unhashed to avoid closed 1693 * socket sitting in hash tables. 1694 */ 1695 sk->sk_state = state; 1696 1697#ifdef STATE_TRACE 1698 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1699#endif 1700} 1701EXPORT_SYMBOL_GPL(tcp_set_state); 1702 1703/* 1704 * State processing on a close. This implements the state shift for 1705 * sending our FIN frame. Note that we only send a FIN for some 1706 * states. A shutdown() may have already sent the FIN, or we may be 1707 * closed. 1708 */ 1709 1710static const unsigned char new_state[16] = { 1711 /* current state: new state: action: */ 1712 /* (Invalid) */ TCP_CLOSE, 1713 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1714 /* TCP_SYN_SENT */ TCP_CLOSE, 1715 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1716 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1717 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1718 /* TCP_TIME_WAIT */ TCP_CLOSE, 1719 /* TCP_CLOSE */ TCP_CLOSE, 1720 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1721 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1722 /* TCP_LISTEN */ TCP_CLOSE, 1723 /* TCP_CLOSING */ TCP_CLOSING, 1724}; 1725 1726static int tcp_close_state(struct sock *sk) 1727{ 1728 int next = (int)new_state[sk->sk_state]; 1729 int ns = next & TCP_STATE_MASK; 1730 1731 tcp_set_state(sk, ns); 1732 1733 return next & TCP_ACTION_FIN; 1734} 1735 1736/* 1737 * Shutdown the sending side of a connection. Much like close except 1738 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1739 */ 1740 1741void tcp_shutdown(struct sock *sk, int how) 1742{ 1743 /* We need to grab some memory, and put together a FIN, 1744 * and then put it into the queue to be sent. 1745 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1746 */ 1747 if (!(how & SEND_SHUTDOWN)) 1748 return; 1749 1750 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1751 if ((1 << sk->sk_state) & 1752 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1753 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1754 /* Clear out any half completed packets. FIN if needed. */ 1755 if (tcp_close_state(sk)) 1756 tcp_send_fin(sk); 1757 } 1758} 1759 1760void tcp_close(struct sock *sk, long timeout) 1761{ 1762 struct sk_buff *skb; 1763 int data_was_unread = 0; 1764 int state; 1765 1766 lock_sock(sk); 1767 sk->sk_shutdown = SHUTDOWN_MASK; 1768 1769 if (sk->sk_state == TCP_LISTEN) { 1770 tcp_set_state(sk, TCP_CLOSE); 1771 1772 /* Special case. */ 1773 inet_csk_listen_stop(sk); 1774 1775 goto adjudge_to_death; 1776 } 1777 1778 /* We need to flush the recv. buffs. We do this only on the 1779 * descriptor close, not protocol-sourced closes, because the 1780 * reader process may not have drained the data yet! 1781 */ 1782 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1783 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1784 tcp_hdr(skb)->fin; 1785 data_was_unread += len; 1786 __kfree_skb(skb); 1787 } 1788 1789 sk_mem_reclaim(sk); 1790 1791 /* As outlined in RFC 2525, section 2.17, we send a RST here because 1792 * data was lost. To witness the awful effects of the old behavior of 1793 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 1794 * GET in an FTP client, suspend the process, wait for the client to 1795 * advertise a zero window, then kill -9 the FTP client, wheee... 1796 * Note: timeout is always zero in such a case. 1797 */ 1798 if (data_was_unread) { 1799 /* Unread data was tossed, zap the connection. */ 1800 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 1801 tcp_set_state(sk, TCP_CLOSE); 1802 tcp_send_active_reset(sk, GFP_KERNEL); 1803 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1804 /* Check zero linger _after_ checking for unread data. */ 1805 sk->sk_prot->disconnect(sk, 0); 1806 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 1807 } else if (tcp_close_state(sk)) { 1808 /* We FIN if the application ate all the data before 1809 * zapping the connection. 1810 */ 1811 1812 /* RED-PEN. Formally speaking, we have broken TCP state 1813 * machine. State transitions: 1814 * 1815 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1816 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1817 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1818 * 1819 * are legal only when FIN has been sent (i.e. in window), 1820 * rather than queued out of window. Purists blame. 1821 * 1822 * F.e. "RFC state" is ESTABLISHED, 1823 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1824 * 1825 * The visible declinations are that sometimes 1826 * we enter time-wait state, when it is not required really 1827 * (harmless), do not send active resets, when they are 1828 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1829 * they look as CLOSING or LAST_ACK for Linux) 1830 * Probably, I missed some more holelets. 1831 * --ANK 1832 */ 1833 tcp_send_fin(sk); 1834 } 1835 1836 sk_stream_wait_close(sk, timeout); 1837 1838adjudge_to_death: 1839 state = sk->sk_state; 1840 sock_hold(sk); 1841 sock_orphan(sk); 1842 1843 /* It is the last release_sock in its life. It will remove backlog. */ 1844 release_sock(sk); 1845 1846 1847 /* Now socket is owned by kernel and we acquire BH lock 1848 to finish close. No need to check for user refs. 1849 */ 1850 local_bh_disable(); 1851 bh_lock_sock(sk); 1852 WARN_ON(sock_owned_by_user(sk)); 1853 1854 percpu_counter_inc(sk->sk_prot->orphan_count); 1855 1856 /* Have we already been destroyed by a softirq or backlog? */ 1857 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 1858 goto out; 1859 1860 /* This is a (useful) BSD violating of the RFC. There is a 1861 * problem with TCP as specified in that the other end could 1862 * keep a socket open forever with no application left this end. 1863 * We use a 3 minute timeout (about the same as BSD) then kill 1864 * our end. If they send after that then tough - BUT: long enough 1865 * that we won't make the old 4*rto = almost no time - whoops 1866 * reset mistake. 1867 * 1868 * Nope, it was not mistake. It is really desired behaviour 1869 * f.e. on http servers, when such sockets are useless, but 1870 * consume significant resources. Let's do it with special 1871 * linger2 option. --ANK 1872 */ 1873 1874 if (sk->sk_state == TCP_FIN_WAIT2) { 1875 struct tcp_sock *tp = tcp_sk(sk); 1876 if (tp->linger2 < 0) { 1877 tcp_set_state(sk, TCP_CLOSE); 1878 tcp_send_active_reset(sk, GFP_ATOMIC); 1879 NET_INC_STATS_BH(sock_net(sk), 1880 LINUX_MIB_TCPABORTONLINGER); 1881 } else { 1882 const int tmo = tcp_fin_time(sk); 1883 1884 if (tmo > TCP_TIMEWAIT_LEN) { 1885 inet_csk_reset_keepalive_timer(sk, 1886 tmo - TCP_TIMEWAIT_LEN); 1887 } else { 1888 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 1889 goto out; 1890 } 1891 } 1892 } 1893 if (sk->sk_state != TCP_CLOSE) { 1894 int orphan_count = percpu_counter_read_positive( 1895 sk->sk_prot->orphan_count); 1896 1897 sk_mem_reclaim(sk); 1898 if (tcp_too_many_orphans(sk, orphan_count)) { 1899 if (net_ratelimit()) 1900 printk(KERN_INFO "TCP: too many of orphaned " 1901 "sockets\n"); 1902 tcp_set_state(sk, TCP_CLOSE); 1903 tcp_send_active_reset(sk, GFP_ATOMIC); 1904 NET_INC_STATS_BH(sock_net(sk), 1905 LINUX_MIB_TCPABORTONMEMORY); 1906 } 1907 } 1908 1909 if (sk->sk_state == TCP_CLOSE) 1910 inet_csk_destroy_sock(sk); 1911 /* Otherwise, socket is reprieved until protocol close. */ 1912 1913out: 1914 bh_unlock_sock(sk); 1915 local_bh_enable(); 1916 sock_put(sk); 1917} 1918 1919/* These states need RST on ABORT according to RFC793 */ 1920 1921static inline int tcp_need_reset(int state) 1922{ 1923 return (1 << state) & 1924 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 1925 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 1926} 1927 1928int tcp_disconnect(struct sock *sk, int flags) 1929{ 1930 struct inet_sock *inet = inet_sk(sk); 1931 struct inet_connection_sock *icsk = inet_csk(sk); 1932 struct tcp_sock *tp = tcp_sk(sk); 1933 int err = 0; 1934 int old_state = sk->sk_state; 1935 1936 if (old_state != TCP_CLOSE) 1937 tcp_set_state(sk, TCP_CLOSE); 1938 1939 /* ABORT function of RFC793 */ 1940 if (old_state == TCP_LISTEN) { 1941 inet_csk_listen_stop(sk); 1942 } else if (tcp_need_reset(old_state) || 1943 (tp->snd_nxt != tp->write_seq && 1944 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 1945 /* The last check adjusts for discrepancy of Linux wrt. RFC 1946 * states 1947 */ 1948 tcp_send_active_reset(sk, gfp_any()); 1949 sk->sk_err = ECONNRESET; 1950 } else if (old_state == TCP_SYN_SENT) 1951 sk->sk_err = ECONNRESET; 1952 1953 tcp_clear_xmit_timers(sk); 1954 __skb_queue_purge(&sk->sk_receive_queue); 1955 tcp_write_queue_purge(sk); 1956 __skb_queue_purge(&tp->out_of_order_queue); 1957#ifdef CONFIG_NET_DMA 1958 __skb_queue_purge(&sk->sk_async_wait_queue); 1959#endif 1960 1961 inet->dport = 0; 1962 1963 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 1964 inet_reset_saddr(sk); 1965 1966 sk->sk_shutdown = 0; 1967 sock_reset_flag(sk, SOCK_DONE); 1968 tp->srtt = 0; 1969 if ((tp->write_seq += tp->max_window + 2) == 0) 1970 tp->write_seq = 1; 1971 icsk->icsk_backoff = 0; 1972 tp->snd_cwnd = 2; 1973 icsk->icsk_probes_out = 0; 1974 tp->packets_out = 0; 1975 tp->snd_ssthresh = 0x7fffffff; 1976 tp->snd_cwnd_cnt = 0; 1977 tp->bytes_acked = 0; 1978 tcp_set_ca_state(sk, TCP_CA_Open); 1979 tcp_clear_retrans(tp); 1980 inet_csk_delack_init(sk); 1981 tcp_init_send_head(sk); 1982 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 1983 __sk_dst_reset(sk); 1984 1985 WARN_ON(inet->num && !icsk->icsk_bind_hash); 1986 1987 sk->sk_error_report(sk); 1988 return err; 1989} 1990 1991/* 1992 * Socket option code for TCP. 1993 */ 1994static int do_tcp_setsockopt(struct sock *sk, int level, 1995 int optname, char __user *optval, int optlen) 1996{ 1997 struct tcp_sock *tp = tcp_sk(sk); 1998 struct inet_connection_sock *icsk = inet_csk(sk); 1999 int val; 2000 int err = 0; 2001 2002 /* This is a string value all the others are int's */ 2003 if (optname == TCP_CONGESTION) { 2004 char name[TCP_CA_NAME_MAX]; 2005 2006 if (optlen < 1) 2007 return -EINVAL; 2008 2009 val = strncpy_from_user(name, optval, 2010 min(TCP_CA_NAME_MAX-1, optlen)); 2011 if (val < 0) 2012 return -EFAULT; 2013 name[val] = 0; 2014 2015 lock_sock(sk); 2016 err = tcp_set_congestion_control(sk, name); 2017 release_sock(sk); 2018 return err; 2019 } 2020 2021 if (optlen < sizeof(int)) 2022 return -EINVAL; 2023 2024 if (get_user(val, (int __user *)optval)) 2025 return -EFAULT; 2026 2027 lock_sock(sk); 2028 2029 switch (optname) { 2030 case TCP_MAXSEG: 2031 /* Values greater than interface MTU won't take effect. However 2032 * at the point when this call is done we typically don't yet 2033 * know which interface is going to be used */ 2034 if (val < 8 || val > MAX_TCP_WINDOW) { 2035 err = -EINVAL; 2036 break; 2037 } 2038 tp->rx_opt.user_mss = val; 2039 break; 2040 2041 case TCP_NODELAY: 2042 if (val) { 2043 /* TCP_NODELAY is weaker than TCP_CORK, so that 2044 * this option on corked socket is remembered, but 2045 * it is not activated until cork is cleared. 2046 * 2047 * However, when TCP_NODELAY is set we make 2048 * an explicit push, which overrides even TCP_CORK 2049 * for currently queued segments. 2050 */ 2051 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2052 tcp_push_pending_frames(sk); 2053 } else { 2054 tp->nonagle &= ~TCP_NAGLE_OFF; 2055 } 2056 break; 2057 2058 case TCP_CORK: 2059 /* When set indicates to always queue non-full frames. 2060 * Later the user clears this option and we transmit 2061 * any pending partial frames in the queue. This is 2062 * meant to be used alongside sendfile() to get properly 2063 * filled frames when the user (for example) must write 2064 * out headers with a write() call first and then use 2065 * sendfile to send out the data parts. 2066 * 2067 * TCP_CORK can be set together with TCP_NODELAY and it is 2068 * stronger than TCP_NODELAY. 2069 */ 2070 if (val) { 2071 tp->nonagle |= TCP_NAGLE_CORK; 2072 } else { 2073 tp->nonagle &= ~TCP_NAGLE_CORK; 2074 if (tp->nonagle&TCP_NAGLE_OFF) 2075 tp->nonagle |= TCP_NAGLE_PUSH; 2076 tcp_push_pending_frames(sk); 2077 } 2078 break; 2079 2080 case TCP_KEEPIDLE: 2081 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2082 err = -EINVAL; 2083 else { 2084 tp->keepalive_time = val * HZ; 2085 if (sock_flag(sk, SOCK_KEEPOPEN) && 2086 !((1 << sk->sk_state) & 2087 (TCPF_CLOSE | TCPF_LISTEN))) { 2088 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; 2089 if (tp->keepalive_time > elapsed) 2090 elapsed = tp->keepalive_time - elapsed; 2091 else 2092 elapsed = 0; 2093 inet_csk_reset_keepalive_timer(sk, elapsed); 2094 } 2095 } 2096 break; 2097 case TCP_KEEPINTVL: 2098 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2099 err = -EINVAL; 2100 else 2101 tp->keepalive_intvl = val * HZ; 2102 break; 2103 case TCP_KEEPCNT: 2104 if (val < 1 || val > MAX_TCP_KEEPCNT) 2105 err = -EINVAL; 2106 else 2107 tp->keepalive_probes = val; 2108 break; 2109 case TCP_SYNCNT: 2110 if (val < 1 || val > MAX_TCP_SYNCNT) 2111 err = -EINVAL; 2112 else 2113 icsk->icsk_syn_retries = val; 2114 break; 2115 2116 case TCP_LINGER2: 2117 if (val < 0) 2118 tp->linger2 = -1; 2119 else if (val > sysctl_tcp_fin_timeout / HZ) 2120 tp->linger2 = 0; 2121 else 2122 tp->linger2 = val * HZ; 2123 break; 2124 2125 case TCP_DEFER_ACCEPT: 2126 icsk->icsk_accept_queue.rskq_defer_accept = 0; 2127 if (val > 0) { 2128 /* Translate value in seconds to number of 2129 * retransmits */ 2130 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && 2131 val > ((TCP_TIMEOUT_INIT / HZ) << 2132 icsk->icsk_accept_queue.rskq_defer_accept)) 2133 icsk->icsk_accept_queue.rskq_defer_accept++; 2134 icsk->icsk_accept_queue.rskq_defer_accept++; 2135 } 2136 break; 2137 2138 case TCP_WINDOW_CLAMP: 2139 if (!val) { 2140 if (sk->sk_state != TCP_CLOSE) { 2141 err = -EINVAL; 2142 break; 2143 } 2144 tp->window_clamp = 0; 2145 } else 2146 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2147 SOCK_MIN_RCVBUF / 2 : val; 2148 break; 2149 2150 case TCP_QUICKACK: 2151 if (!val) { 2152 icsk->icsk_ack.pingpong = 1; 2153 } else { 2154 icsk->icsk_ack.pingpong = 0; 2155 if ((1 << sk->sk_state) & 2156 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2157 inet_csk_ack_scheduled(sk)) { 2158 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2159 tcp_cleanup_rbuf(sk, 1); 2160 if (!(val & 1)) 2161 icsk->icsk_ack.pingpong = 1; 2162 } 2163 } 2164 break; 2165 2166#ifdef CONFIG_TCP_MD5SIG 2167 case TCP_MD5SIG: 2168 /* Read the IP->Key mappings from userspace */ 2169 err = tp->af_specific->md5_parse(sk, optval, optlen); 2170 break; 2171#endif 2172 2173 default: 2174 err = -ENOPROTOOPT; 2175 break; 2176 } 2177 2178 release_sock(sk); 2179 return err; 2180} 2181 2182int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2183 int optlen) 2184{ 2185 struct inet_connection_sock *icsk = inet_csk(sk); 2186 2187 if (level != SOL_TCP) 2188 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2189 optval, optlen); 2190 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2191} 2192 2193#ifdef CONFIG_COMPAT 2194int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2195 char __user *optval, int optlen) 2196{ 2197 if (level != SOL_TCP) 2198 return inet_csk_compat_setsockopt(sk, level, optname, 2199 optval, optlen); 2200 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2201} 2202 2203EXPORT_SYMBOL(compat_tcp_setsockopt); 2204#endif 2205 2206/* Return information about state of tcp endpoint in API format. */ 2207void tcp_get_info(struct sock *sk, struct tcp_info *info) 2208{ 2209 struct tcp_sock *tp = tcp_sk(sk); 2210 const struct inet_connection_sock *icsk = inet_csk(sk); 2211 u32 now = tcp_time_stamp; 2212 2213 memset(info, 0, sizeof(*info)); 2214 2215 info->tcpi_state = sk->sk_state; 2216 info->tcpi_ca_state = icsk->icsk_ca_state; 2217 info->tcpi_retransmits = icsk->icsk_retransmits; 2218 info->tcpi_probes = icsk->icsk_probes_out; 2219 info->tcpi_backoff = icsk->icsk_backoff; 2220 2221 if (tp->rx_opt.tstamp_ok) 2222 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2223 if (tcp_is_sack(tp)) 2224 info->tcpi_options |= TCPI_OPT_SACK; 2225 if (tp->rx_opt.wscale_ok) { 2226 info->tcpi_options |= TCPI_OPT_WSCALE; 2227 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2228 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2229 } 2230 2231 if (tp->ecn_flags&TCP_ECN_OK) 2232 info->tcpi_options |= TCPI_OPT_ECN; 2233 2234 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2235 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2236 info->tcpi_snd_mss = tp->mss_cache; 2237 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2238 2239 if (sk->sk_state == TCP_LISTEN) { 2240 info->tcpi_unacked = sk->sk_ack_backlog; 2241 info->tcpi_sacked = sk->sk_max_ack_backlog; 2242 } else { 2243 info->tcpi_unacked = tp->packets_out; 2244 info->tcpi_sacked = tp->sacked_out; 2245 } 2246 info->tcpi_lost = tp->lost_out; 2247 info->tcpi_retrans = tp->retrans_out; 2248 info->tcpi_fackets = tp->fackets_out; 2249 2250 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2251 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2252 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2253 2254 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2255 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2256 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2257 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2258 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2259 info->tcpi_snd_cwnd = tp->snd_cwnd; 2260 info->tcpi_advmss = tp->advmss; 2261 info->tcpi_reordering = tp->reordering; 2262 2263 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2264 info->tcpi_rcv_space = tp->rcvq_space.space; 2265 2266 info->tcpi_total_retrans = tp->total_retrans; 2267} 2268 2269EXPORT_SYMBOL_GPL(tcp_get_info); 2270 2271static int do_tcp_getsockopt(struct sock *sk, int level, 2272 int optname, char __user *optval, int __user *optlen) 2273{ 2274 struct inet_connection_sock *icsk = inet_csk(sk); 2275 struct tcp_sock *tp = tcp_sk(sk); 2276 int val, len; 2277 2278 if (get_user(len, optlen)) 2279 return -EFAULT; 2280 2281 len = min_t(unsigned int, len, sizeof(int)); 2282 2283 if (len < 0) 2284 return -EINVAL; 2285 2286 switch (optname) { 2287 case TCP_MAXSEG: 2288 val = tp->mss_cache; 2289 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2290 val = tp->rx_opt.user_mss; 2291 break; 2292 case TCP_NODELAY: 2293 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2294 break; 2295 case TCP_CORK: 2296 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2297 break; 2298 case TCP_KEEPIDLE: 2299 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2300 break; 2301 case TCP_KEEPINTVL: 2302 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2303 break; 2304 case TCP_KEEPCNT: 2305 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2306 break; 2307 case TCP_SYNCNT: 2308 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2309 break; 2310 case TCP_LINGER2: 2311 val = tp->linger2; 2312 if (val >= 0) 2313 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2314 break; 2315 case TCP_DEFER_ACCEPT: 2316 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2317 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2318 break; 2319 case TCP_WINDOW_CLAMP: 2320 val = tp->window_clamp; 2321 break; 2322 case TCP_INFO: { 2323 struct tcp_info info; 2324 2325 if (get_user(len, optlen)) 2326 return -EFAULT; 2327 2328 tcp_get_info(sk, &info); 2329 2330 len = min_t(unsigned int, len, sizeof(info)); 2331 if (put_user(len, optlen)) 2332 return -EFAULT; 2333 if (copy_to_user(optval, &info, len)) 2334 return -EFAULT; 2335 return 0; 2336 } 2337 case TCP_QUICKACK: 2338 val = !icsk->icsk_ack.pingpong; 2339 break; 2340 2341 case TCP_CONGESTION: 2342 if (get_user(len, optlen)) 2343 return -EFAULT; 2344 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2345 if (put_user(len, optlen)) 2346 return -EFAULT; 2347 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2348 return -EFAULT; 2349 return 0; 2350 default: 2351 return -ENOPROTOOPT; 2352 } 2353 2354 if (put_user(len, optlen)) 2355 return -EFAULT; 2356 if (copy_to_user(optval, &val, len)) 2357 return -EFAULT; 2358 return 0; 2359} 2360 2361int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2362 int __user *optlen) 2363{ 2364 struct inet_connection_sock *icsk = inet_csk(sk); 2365 2366 if (level != SOL_TCP) 2367 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2368 optval, optlen); 2369 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2370} 2371 2372#ifdef CONFIG_COMPAT 2373int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2374 char __user *optval, int __user *optlen) 2375{ 2376 if (level != SOL_TCP) 2377 return inet_csk_compat_getsockopt(sk, level, optname, 2378 optval, optlen); 2379 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2380} 2381 2382EXPORT_SYMBOL(compat_tcp_getsockopt); 2383#endif 2384 2385struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2386{ 2387 struct sk_buff *segs = ERR_PTR(-EINVAL); 2388 struct tcphdr *th; 2389 unsigned thlen; 2390 unsigned int seq; 2391 __be32 delta; 2392 unsigned int oldlen; 2393 unsigned int mss; 2394 2395 if (!pskb_may_pull(skb, sizeof(*th))) 2396 goto out; 2397 2398 th = tcp_hdr(skb); 2399 thlen = th->doff * 4; 2400 if (thlen < sizeof(*th)) 2401 goto out; 2402 2403 if (!pskb_may_pull(skb, thlen)) 2404 goto out; 2405 2406 oldlen = (u16)~skb->len; 2407 __skb_pull(skb, thlen); 2408 2409 mss = skb_shinfo(skb)->gso_size; 2410 if (unlikely(skb->len <= mss)) 2411 goto out; 2412 2413 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2414 /* Packet is from an untrusted source, reset gso_segs. */ 2415 int type = skb_shinfo(skb)->gso_type; 2416 2417 if (unlikely(type & 2418 ~(SKB_GSO_TCPV4 | 2419 SKB_GSO_DODGY | 2420 SKB_GSO_TCP_ECN | 2421 SKB_GSO_TCPV6 | 2422 0) || 2423 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2424 goto out; 2425 2426 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 2427 2428 segs = NULL; 2429 goto out; 2430 } 2431 2432 segs = skb_segment(skb, features); 2433 if (IS_ERR(segs)) 2434 goto out; 2435 2436 delta = htonl(oldlen + (thlen + mss)); 2437 2438 skb = segs; 2439 th = tcp_hdr(skb); 2440 seq = ntohl(th->seq); 2441 2442 do { 2443 th->fin = th->psh = 0; 2444 2445 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2446 (__force u32)delta)); 2447 if (skb->ip_summed != CHECKSUM_PARTIAL) 2448 th->check = 2449 csum_fold(csum_partial(skb_transport_header(skb), 2450 thlen, skb->csum)); 2451 2452 seq += mss; 2453 skb = skb->next; 2454 th = tcp_hdr(skb); 2455 2456 th->seq = htonl(seq); 2457 th->cwr = 0; 2458 } while (skb->next); 2459 2460 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2461 skb->data_len); 2462 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2463 (__force u32)delta)); 2464 if (skb->ip_summed != CHECKSUM_PARTIAL) 2465 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2466 thlen, skb->csum)); 2467 2468out: 2469 return segs; 2470} 2471EXPORT_SYMBOL(tcp_tso_segment); 2472 2473struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) 2474{ 2475 struct sk_buff **pp = NULL; 2476 struct sk_buff *p; 2477 struct tcphdr *th; 2478 struct tcphdr *th2; 2479 unsigned int thlen; 2480 unsigned int flags; 2481 unsigned int total; 2482 unsigned int mss = 1; 2483 int flush = 1; 2484 2485 if (!pskb_may_pull(skb, sizeof(*th))) 2486 goto out; 2487 2488 th = tcp_hdr(skb); 2489 thlen = th->doff * 4; 2490 if (thlen < sizeof(*th)) 2491 goto out; 2492 2493 if (!pskb_may_pull(skb, thlen)) 2494 goto out; 2495 2496 th = tcp_hdr(skb); 2497 __skb_pull(skb, thlen); 2498 2499 flags = tcp_flag_word(th); 2500 2501 for (; (p = *head); head = &p->next) { 2502 if (!NAPI_GRO_CB(p)->same_flow) 2503 continue; 2504 2505 th2 = tcp_hdr(p); 2506 2507 if (th->source != th2->source || th->dest != th2->dest) { 2508 NAPI_GRO_CB(p)->same_flow = 0; 2509 continue; 2510 } 2511 2512 goto found; 2513 } 2514 2515 goto out_check_final; 2516 2517found: 2518 flush = NAPI_GRO_CB(p)->flush; 2519 flush |= flags & TCP_FLAG_CWR; 2520 flush |= (flags ^ tcp_flag_word(th2)) & 2521 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH); 2522 flush |= th->ack_seq != th2->ack_seq || th->window != th2->window; 2523 flush |= memcmp(th + 1, th2 + 1, thlen - sizeof(*th)); 2524 2525 total = p->len; 2526 mss = skb_shinfo(p)->gso_size; 2527 2528 flush |= skb->len > mss || skb->len <= 0; 2529 flush |= ntohl(th2->seq) + total != ntohl(th->seq); 2530 2531 if (flush || skb_gro_receive(head, skb)) { 2532 mss = 1; 2533 goto out_check_final; 2534 } 2535 2536 p = *head; 2537 th2 = tcp_hdr(p); 2538 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); 2539 2540out_check_final: 2541 flush = skb->len < mss; 2542 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST | 2543 TCP_FLAG_SYN | TCP_FLAG_FIN); 2544 2545 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) 2546 pp = head; 2547 2548out: 2549 NAPI_GRO_CB(skb)->flush |= flush; 2550 2551 return pp; 2552} 2553EXPORT_SYMBOL(tcp_gro_receive); 2554 2555int tcp_gro_complete(struct sk_buff *skb) 2556{ 2557 struct tcphdr *th = tcp_hdr(skb); 2558 2559 skb->csum_start = skb_transport_header(skb) - skb->head; 2560 skb->csum_offset = offsetof(struct tcphdr, check); 2561 skb->ip_summed = CHECKSUM_PARTIAL; 2562 2563 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 2564 2565 if (th->cwr) 2566 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 2567 2568 return 0; 2569} 2570EXPORT_SYMBOL(tcp_gro_complete); 2571 2572#ifdef CONFIG_TCP_MD5SIG 2573static unsigned long tcp_md5sig_users; 2574static struct tcp_md5sig_pool **tcp_md5sig_pool; 2575static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2576 2577static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2578{ 2579 int cpu; 2580 for_each_possible_cpu(cpu) { 2581 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2582 if (p) { 2583 if (p->md5_desc.tfm) 2584 crypto_free_hash(p->md5_desc.tfm); 2585 kfree(p); 2586 p = NULL; 2587 } 2588 } 2589 free_percpu(pool); 2590} 2591 2592void tcp_free_md5sig_pool(void) 2593{ 2594 struct tcp_md5sig_pool **pool = NULL; 2595 2596 spin_lock_bh(&tcp_md5sig_pool_lock); 2597 if (--tcp_md5sig_users == 0) { 2598 pool = tcp_md5sig_pool; 2599 tcp_md5sig_pool = NULL; 2600 } 2601 spin_unlock_bh(&tcp_md5sig_pool_lock); 2602 if (pool) 2603 __tcp_free_md5sig_pool(pool); 2604} 2605 2606EXPORT_SYMBOL(tcp_free_md5sig_pool); 2607 2608static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2609{ 2610 int cpu; 2611 struct tcp_md5sig_pool **pool; 2612 2613 pool = alloc_percpu(struct tcp_md5sig_pool *); 2614 if (!pool) 2615 return NULL; 2616 2617 for_each_possible_cpu(cpu) { 2618 struct tcp_md5sig_pool *p; 2619 struct crypto_hash *hash; 2620 2621 p = kzalloc(sizeof(*p), GFP_KERNEL); 2622 if (!p) 2623 goto out_free; 2624 *per_cpu_ptr(pool, cpu) = p; 2625 2626 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2627 if (!hash || IS_ERR(hash)) 2628 goto out_free; 2629 2630 p->md5_desc.tfm = hash; 2631 } 2632 return pool; 2633out_free: 2634 __tcp_free_md5sig_pool(pool); 2635 return NULL; 2636} 2637 2638struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2639{ 2640 struct tcp_md5sig_pool **pool; 2641 int alloc = 0; 2642 2643retry: 2644 spin_lock_bh(&tcp_md5sig_pool_lock); 2645 pool = tcp_md5sig_pool; 2646 if (tcp_md5sig_users++ == 0) { 2647 alloc = 1; 2648 spin_unlock_bh(&tcp_md5sig_pool_lock); 2649 } else if (!pool) { 2650 tcp_md5sig_users--; 2651 spin_unlock_bh(&tcp_md5sig_pool_lock); 2652 cpu_relax(); 2653 goto retry; 2654 } else 2655 spin_unlock_bh(&tcp_md5sig_pool_lock); 2656 2657 if (alloc) { 2658 /* we cannot hold spinlock here because this may sleep. */ 2659 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2660 spin_lock_bh(&tcp_md5sig_pool_lock); 2661 if (!p) { 2662 tcp_md5sig_users--; 2663 spin_unlock_bh(&tcp_md5sig_pool_lock); 2664 return NULL; 2665 } 2666 pool = tcp_md5sig_pool; 2667 if (pool) { 2668 /* oops, it has already been assigned. */ 2669 spin_unlock_bh(&tcp_md5sig_pool_lock); 2670 __tcp_free_md5sig_pool(p); 2671 } else { 2672 tcp_md5sig_pool = pool = p; 2673 spin_unlock_bh(&tcp_md5sig_pool_lock); 2674 } 2675 } 2676 return pool; 2677} 2678 2679EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2680 2681struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2682{ 2683 struct tcp_md5sig_pool **p; 2684 spin_lock_bh(&tcp_md5sig_pool_lock); 2685 p = tcp_md5sig_pool; 2686 if (p) 2687 tcp_md5sig_users++; 2688 spin_unlock_bh(&tcp_md5sig_pool_lock); 2689 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2690} 2691 2692EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2693 2694void __tcp_put_md5sig_pool(void) 2695{ 2696 tcp_free_md5sig_pool(); 2697} 2698 2699EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2700 2701int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 2702 struct tcphdr *th) 2703{ 2704 struct scatterlist sg; 2705 int err; 2706 2707 __sum16 old_checksum = th->check; 2708 th->check = 0; 2709 /* options aren't included in the hash */ 2710 sg_init_one(&sg, th, sizeof(struct tcphdr)); 2711 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr)); 2712 th->check = old_checksum; 2713 return err; 2714} 2715 2716EXPORT_SYMBOL(tcp_md5_hash_header); 2717 2718int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 2719 struct sk_buff *skb, unsigned header_len) 2720{ 2721 struct scatterlist sg; 2722 const struct tcphdr *tp = tcp_hdr(skb); 2723 struct hash_desc *desc = &hp->md5_desc; 2724 unsigned i; 2725 const unsigned head_data_len = skb_headlen(skb) > header_len ? 2726 skb_headlen(skb) - header_len : 0; 2727 const struct skb_shared_info *shi = skb_shinfo(skb); 2728 2729 sg_init_table(&sg, 1); 2730 2731 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 2732 if (crypto_hash_update(desc, &sg, head_data_len)) 2733 return 1; 2734 2735 for (i = 0; i < shi->nr_frags; ++i) { 2736 const struct skb_frag_struct *f = &shi->frags[i]; 2737 sg_set_page(&sg, f->page, f->size, f->page_offset); 2738 if (crypto_hash_update(desc, &sg, f->size)) 2739 return 1; 2740 } 2741 2742 return 0; 2743} 2744 2745EXPORT_SYMBOL(tcp_md5_hash_skb_data); 2746 2747int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key) 2748{ 2749 struct scatterlist sg; 2750 2751 sg_init_one(&sg, key->key, key->keylen); 2752 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 2753} 2754 2755EXPORT_SYMBOL(tcp_md5_hash_key); 2756 2757#endif 2758 2759void tcp_done(struct sock *sk) 2760{ 2761 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2762 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 2763 2764 tcp_set_state(sk, TCP_CLOSE); 2765 tcp_clear_xmit_timers(sk); 2766 2767 sk->sk_shutdown = SHUTDOWN_MASK; 2768 2769 if (!sock_flag(sk, SOCK_DEAD)) 2770 sk->sk_state_change(sk); 2771 else 2772 inet_csk_destroy_sock(sk); 2773} 2774EXPORT_SYMBOL_GPL(tcp_done); 2775 2776extern struct tcp_congestion_ops tcp_reno; 2777 2778static __initdata unsigned long thash_entries; 2779static int __init set_thash_entries(char *str) 2780{ 2781 if (!str) 2782 return 0; 2783 thash_entries = simple_strtoul(str, &str, 0); 2784 return 1; 2785} 2786__setup("thash_entries=", set_thash_entries); 2787 2788void __init tcp_init(void) 2789{ 2790 struct sk_buff *skb = NULL; 2791 unsigned long nr_pages, limit; 2792 int order, i, max_share; 2793 2794 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 2795 2796 percpu_counter_init(&tcp_sockets_allocated, 0); 2797 percpu_counter_init(&tcp_orphan_count, 0); 2798 tcp_hashinfo.bind_bucket_cachep = 2799 kmem_cache_create("tcp_bind_bucket", 2800 sizeof(struct inet_bind_bucket), 0, 2801 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2802 2803 /* Size and allocate the main established and bind bucket 2804 * hash tables. 2805 * 2806 * The methodology is similar to that of the buffer cache. 2807 */ 2808 tcp_hashinfo.ehash = 2809 alloc_large_system_hash("TCP established", 2810 sizeof(struct inet_ehash_bucket), 2811 thash_entries, 2812 (num_physpages >= 128 * 1024) ? 2813 13 : 15, 2814 0, 2815 &tcp_hashinfo.ehash_size, 2816 NULL, 2817 thash_entries ? 0 : 512 * 1024); 2818 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2819 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2820 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 2821 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); 2822 } 2823 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 2824 panic("TCP: failed to alloc ehash_locks"); 2825 tcp_hashinfo.bhash = 2826 alloc_large_system_hash("TCP bind", 2827 sizeof(struct inet_bind_hashbucket), 2828 tcp_hashinfo.ehash_size, 2829 (num_physpages >= 128 * 1024) ? 2830 13 : 15, 2831 0, 2832 &tcp_hashinfo.bhash_size, 2833 NULL, 2834 64 * 1024); 2835 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2836 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2837 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2838 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2839 } 2840 2841 /* Try to be a bit smarter and adjust defaults depending 2842 * on available memory. 2843 */ 2844 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2845 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2846 order++) 2847 ; 2848 if (order >= 4) { 2849 tcp_death_row.sysctl_max_tw_buckets = 180000; 2850 sysctl_tcp_max_orphans = 4096 << (order - 4); 2851 sysctl_max_syn_backlog = 1024; 2852 } else if (order < 3) { 2853 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2854 sysctl_tcp_max_orphans >>= (3 - order); 2855 sysctl_max_syn_backlog = 128; 2856 } 2857 2858 /* Set the pressure threshold to be a fraction of global memory that 2859 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2860 * memory, with a floor of 128 pages. 2861 */ 2862 nr_pages = totalram_pages - totalhigh_pages; 2863 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2864 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2865 limit = max(limit, 128UL); 2866 sysctl_tcp_mem[0] = limit / 4 * 3; 2867 sysctl_tcp_mem[1] = limit; 2868 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2869 2870 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2871 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2872 max_share = min(4UL*1024*1024, limit); 2873 2874 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 2875 sysctl_tcp_wmem[1] = 16*1024; 2876 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2877 2878 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 2879 sysctl_tcp_rmem[1] = 87380; 2880 sysctl_tcp_rmem[2] = max(87380, max_share); 2881 2882 printk(KERN_INFO "TCP: Hash tables configured " 2883 "(established %d bind %d)\n", 2884 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2885 2886 tcp_register_congestion_control(&tcp_reno); 2887} 2888 2889EXPORT_SYMBOL(tcp_close); 2890EXPORT_SYMBOL(tcp_disconnect); 2891EXPORT_SYMBOL(tcp_getsockopt); 2892EXPORT_SYMBOL(tcp_ioctl); 2893EXPORT_SYMBOL(tcp_poll); 2894EXPORT_SYMBOL(tcp_read_sock); 2895EXPORT_SYMBOL(tcp_recvmsg); 2896EXPORT_SYMBOL(tcp_sendmsg); 2897EXPORT_SYMBOL(tcp_splice_read); 2898EXPORT_SYMBOL(tcp_sendpage); 2899EXPORT_SYMBOL(tcp_setsockopt); 2900EXPORT_SYMBOL(tcp_shutdown); 2901