tcp.c revision e11ecddf5128011c936cc5360780190cbc901fdc
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#define pr_fmt(fmt) "TCP: " fmt 249 250#include <linux/kernel.h> 251#include <linux/module.h> 252#include <linux/types.h> 253#include <linux/fcntl.h> 254#include <linux/poll.h> 255#include <linux/init.h> 256#include <linux/fs.h> 257#include <linux/skbuff.h> 258#include <linux/scatterlist.h> 259#include <linux/splice.h> 260#include <linux/net.h> 261#include <linux/socket.h> 262#include <linux/random.h> 263#include <linux/bootmem.h> 264#include <linux/highmem.h> 265#include <linux/swap.h> 266#include <linux/cache.h> 267#include <linux/err.h> 268#include <linux/crypto.h> 269#include <linux/time.h> 270#include <linux/slab.h> 271 272#include <net/icmp.h> 273#include <net/inet_common.h> 274#include <net/tcp.h> 275#include <net/xfrm.h> 276#include <net/ip.h> 277#include <net/netdma.h> 278#include <net/sock.h> 279 280#include <asm/uaccess.h> 281#include <asm/ioctls.h> 282#include <net/busy_poll.h> 283 284int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 285 286int sysctl_tcp_min_tso_segs __read_mostly = 2; 287 288int sysctl_tcp_autocorking __read_mostly = 1; 289 290struct percpu_counter tcp_orphan_count; 291EXPORT_SYMBOL_GPL(tcp_orphan_count); 292 293long sysctl_tcp_mem[3] __read_mostly; 294int sysctl_tcp_wmem[3] __read_mostly; 295int sysctl_tcp_rmem[3] __read_mostly; 296 297EXPORT_SYMBOL(sysctl_tcp_mem); 298EXPORT_SYMBOL(sysctl_tcp_rmem); 299EXPORT_SYMBOL(sysctl_tcp_wmem); 300 301atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ 302EXPORT_SYMBOL(tcp_memory_allocated); 303 304/* 305 * Current number of TCP sockets. 306 */ 307struct percpu_counter tcp_sockets_allocated; 308EXPORT_SYMBOL(tcp_sockets_allocated); 309 310/* 311 * TCP splice context 312 */ 313struct tcp_splice_state { 314 struct pipe_inode_info *pipe; 315 size_t len; 316 unsigned int flags; 317}; 318 319/* 320 * Pressure flag: try to collapse. 321 * Technical note: it is used by multiple contexts non atomically. 322 * All the __sk_mem_schedule() is of this nature: accounting 323 * is strict, actions are advisory and have some latency. 324 */ 325int tcp_memory_pressure __read_mostly; 326EXPORT_SYMBOL(tcp_memory_pressure); 327 328void tcp_enter_memory_pressure(struct sock *sk) 329{ 330 if (!tcp_memory_pressure) { 331 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 332 tcp_memory_pressure = 1; 333 } 334} 335EXPORT_SYMBOL(tcp_enter_memory_pressure); 336 337/* Convert seconds to retransmits based on initial and max timeout */ 338static u8 secs_to_retrans(int seconds, int timeout, int rto_max) 339{ 340 u8 res = 0; 341 342 if (seconds > 0) { 343 int period = timeout; 344 345 res = 1; 346 while (seconds > period && res < 255) { 347 res++; 348 timeout <<= 1; 349 if (timeout > rto_max) 350 timeout = rto_max; 351 period += timeout; 352 } 353 } 354 return res; 355} 356 357/* Convert retransmits to seconds based on initial and max timeout */ 358static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 359{ 360 int period = 0; 361 362 if (retrans > 0) { 363 period = timeout; 364 while (--retrans) { 365 timeout <<= 1; 366 if (timeout > rto_max) 367 timeout = rto_max; 368 period += timeout; 369 } 370 } 371 return period; 372} 373 374/* Address-family independent initialization for a tcp_sock. 375 * 376 * NOTE: A lot of things set to zero explicitly by call to 377 * sk_alloc() so need not be done here. 378 */ 379void tcp_init_sock(struct sock *sk) 380{ 381 struct inet_connection_sock *icsk = inet_csk(sk); 382 struct tcp_sock *tp = tcp_sk(sk); 383 384 __skb_queue_head_init(&tp->out_of_order_queue); 385 tcp_init_xmit_timers(sk); 386 tcp_prequeue_init(tp); 387 INIT_LIST_HEAD(&tp->tsq_node); 388 389 icsk->icsk_rto = TCP_TIMEOUT_INIT; 390 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); 391 392 /* So many TCP implementations out there (incorrectly) count the 393 * initial SYN frame in their delayed-ACK and congestion control 394 * algorithms that we must have the following bandaid to talk 395 * efficiently to them. -DaveM 396 */ 397 tp->snd_cwnd = TCP_INIT_CWND; 398 399 /* See draft-stevens-tcpca-spec-01 for discussion of the 400 * initialization of these values. 401 */ 402 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 403 tp->snd_cwnd_clamp = ~0; 404 tp->mss_cache = TCP_MSS_DEFAULT; 405 406 tp->reordering = sysctl_tcp_reordering; 407 tcp_enable_early_retrans(tp); 408 icsk->icsk_ca_ops = &tcp_init_congestion_ops; 409 410 tp->tsoffset = 0; 411 412 sk->sk_state = TCP_CLOSE; 413 414 sk->sk_write_space = sk_stream_write_space; 415 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 416 417 icsk->icsk_sync_mss = tcp_sync_mss; 418 419 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 420 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 421 422 local_bh_disable(); 423 sock_update_memcg(sk); 424 sk_sockets_allocated_inc(sk); 425 local_bh_enable(); 426} 427EXPORT_SYMBOL(tcp_init_sock); 428 429static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb) 430{ 431 if (sk->sk_tsflags) { 432 struct skb_shared_info *shinfo = skb_shinfo(skb); 433 434 sock_tx_timestamp(sk, &shinfo->tx_flags); 435 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP) 436 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; 437 } 438} 439 440/* 441 * Wait for a TCP event. 442 * 443 * Note that we don't need to lock the socket, as the upper poll layers 444 * take care of normal races (between the test and the event) and we don't 445 * go look at any of the socket buffers directly. 446 */ 447unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 448{ 449 unsigned int mask; 450 struct sock *sk = sock->sk; 451 const struct tcp_sock *tp = tcp_sk(sk); 452 453 sock_rps_record_flow(sk); 454 455 sock_poll_wait(file, sk_sleep(sk), wait); 456 if (sk->sk_state == TCP_LISTEN) 457 return inet_csk_listen_poll(sk); 458 459 /* Socket is not locked. We are protected from async events 460 * by poll logic and correct handling of state changes 461 * made by other threads is impossible in any case. 462 */ 463 464 mask = 0; 465 466 /* 467 * POLLHUP is certainly not done right. But poll() doesn't 468 * have a notion of HUP in just one direction, and for a 469 * socket the read side is more interesting. 470 * 471 * Some poll() documentation says that POLLHUP is incompatible 472 * with the POLLOUT/POLLWR flags, so somebody should check this 473 * all. But careful, it tends to be safer to return too many 474 * bits than too few, and you can easily break real applications 475 * if you don't tell them that something has hung up! 476 * 477 * Check-me. 478 * 479 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 480 * our fs/select.c). It means that after we received EOF, 481 * poll always returns immediately, making impossible poll() on write() 482 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 483 * if and only if shutdown has been made in both directions. 484 * Actually, it is interesting to look how Solaris and DUX 485 * solve this dilemma. I would prefer, if POLLHUP were maskable, 486 * then we could set it on SND_SHUTDOWN. BTW examples given 487 * in Stevens' books assume exactly this behaviour, it explains 488 * why POLLHUP is incompatible with POLLOUT. --ANK 489 * 490 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 491 * blocking on fresh not-connected or disconnected socket. --ANK 492 */ 493 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 494 mask |= POLLHUP; 495 if (sk->sk_shutdown & RCV_SHUTDOWN) 496 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 497 498 /* Connected or passive Fast Open socket? */ 499 if (sk->sk_state != TCP_SYN_SENT && 500 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) { 501 int target = sock_rcvlowat(sk, 0, INT_MAX); 502 503 if (tp->urg_seq == tp->copied_seq && 504 !sock_flag(sk, SOCK_URGINLINE) && 505 tp->urg_data) 506 target++; 507 508 /* Potential race condition. If read of tp below will 509 * escape above sk->sk_state, we can be illegally awaken 510 * in SYN_* states. */ 511 if (tp->rcv_nxt - tp->copied_seq >= target) 512 mask |= POLLIN | POLLRDNORM; 513 514 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 515 if (sk_stream_is_writeable(sk)) { 516 mask |= POLLOUT | POLLWRNORM; 517 } else { /* send SIGIO later */ 518 set_bit(SOCK_ASYNC_NOSPACE, 519 &sk->sk_socket->flags); 520 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 521 522 /* Race breaker. If space is freed after 523 * wspace test but before the flags are set, 524 * IO signal will be lost. 525 */ 526 if (sk_stream_is_writeable(sk)) 527 mask |= POLLOUT | POLLWRNORM; 528 } 529 } else 530 mask |= POLLOUT | POLLWRNORM; 531 532 if (tp->urg_data & TCP_URG_VALID) 533 mask |= POLLPRI; 534 } 535 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 536 smp_rmb(); 537 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 538 mask |= POLLERR; 539 540 return mask; 541} 542EXPORT_SYMBOL(tcp_poll); 543 544int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 545{ 546 struct tcp_sock *tp = tcp_sk(sk); 547 int answ; 548 bool slow; 549 550 switch (cmd) { 551 case SIOCINQ: 552 if (sk->sk_state == TCP_LISTEN) 553 return -EINVAL; 554 555 slow = lock_sock_fast(sk); 556 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 557 answ = 0; 558 else if (sock_flag(sk, SOCK_URGINLINE) || 559 !tp->urg_data || 560 before(tp->urg_seq, tp->copied_seq) || 561 !before(tp->urg_seq, tp->rcv_nxt)) { 562 563 answ = tp->rcv_nxt - tp->copied_seq; 564 565 /* Subtract 1, if FIN was received */ 566 if (answ && sock_flag(sk, SOCK_DONE)) 567 answ--; 568 } else 569 answ = tp->urg_seq - tp->copied_seq; 570 unlock_sock_fast(sk, slow); 571 break; 572 case SIOCATMARK: 573 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 574 break; 575 case SIOCOUTQ: 576 if (sk->sk_state == TCP_LISTEN) 577 return -EINVAL; 578 579 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 580 answ = 0; 581 else 582 answ = tp->write_seq - tp->snd_una; 583 break; 584 case SIOCOUTQNSD: 585 if (sk->sk_state == TCP_LISTEN) 586 return -EINVAL; 587 588 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 589 answ = 0; 590 else 591 answ = tp->write_seq - tp->snd_nxt; 592 break; 593 default: 594 return -ENOIOCTLCMD; 595 } 596 597 return put_user(answ, (int __user *)arg); 598} 599EXPORT_SYMBOL(tcp_ioctl); 600 601static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 602{ 603 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH; 604 tp->pushed_seq = tp->write_seq; 605} 606 607static inline bool forced_push(const struct tcp_sock *tp) 608{ 609 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 610} 611 612static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 613{ 614 struct tcp_sock *tp = tcp_sk(sk); 615 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 616 617 skb->csum = 0; 618 tcb->seq = tcb->end_seq = tp->write_seq; 619 tcb->tcp_flags = TCPHDR_ACK; 620 tcb->sacked = 0; 621 skb_header_release(skb); 622 tcp_add_write_queue_tail(sk, skb); 623 sk->sk_wmem_queued += skb->truesize; 624 sk_mem_charge(sk, skb->truesize); 625 if (tp->nonagle & TCP_NAGLE_PUSH) 626 tp->nonagle &= ~TCP_NAGLE_PUSH; 627} 628 629static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 630{ 631 if (flags & MSG_OOB) 632 tp->snd_up = tp->write_seq; 633} 634 635/* If a not yet filled skb is pushed, do not send it if 636 * we have data packets in Qdisc or NIC queues : 637 * Because TX completion will happen shortly, it gives a chance 638 * to coalesce future sendmsg() payload into this skb, without 639 * need for a timer, and with no latency trade off. 640 * As packets containing data payload have a bigger truesize 641 * than pure acks (dataless) packets, the last checks prevent 642 * autocorking if we only have an ACK in Qdisc/NIC queues, 643 * or if TX completion was delayed after we processed ACK packet. 644 */ 645static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb, 646 int size_goal) 647{ 648 return skb->len < size_goal && 649 sysctl_tcp_autocorking && 650 skb != tcp_write_queue_head(sk) && 651 atomic_read(&sk->sk_wmem_alloc) > skb->truesize; 652} 653 654static void tcp_push(struct sock *sk, int flags, int mss_now, 655 int nonagle, int size_goal) 656{ 657 struct tcp_sock *tp = tcp_sk(sk); 658 struct sk_buff *skb; 659 660 if (!tcp_send_head(sk)) 661 return; 662 663 skb = tcp_write_queue_tail(sk); 664 if (!(flags & MSG_MORE) || forced_push(tp)) 665 tcp_mark_push(tp, skb); 666 667 tcp_mark_urg(tp, flags); 668 669 if (tcp_should_autocork(sk, skb, size_goal)) { 670 671 /* avoid atomic op if TSQ_THROTTLED bit is already set */ 672 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) { 673 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); 674 set_bit(TSQ_THROTTLED, &tp->tsq_flags); 675 } 676 /* It is possible TX completion already happened 677 * before we set TSQ_THROTTLED. 678 */ 679 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize) 680 return; 681 } 682 683 if (flags & MSG_MORE) 684 nonagle = TCP_NAGLE_CORK; 685 686 __tcp_push_pending_frames(sk, mss_now, nonagle); 687} 688 689static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 690 unsigned int offset, size_t len) 691{ 692 struct tcp_splice_state *tss = rd_desc->arg.data; 693 int ret; 694 695 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 696 tss->flags); 697 if (ret > 0) 698 rd_desc->count -= ret; 699 return ret; 700} 701 702static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 703{ 704 /* Store TCP splice context information in read_descriptor_t. */ 705 read_descriptor_t rd_desc = { 706 .arg.data = tss, 707 .count = tss->len, 708 }; 709 710 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 711} 712 713/** 714 * tcp_splice_read - splice data from TCP socket to a pipe 715 * @sock: socket to splice from 716 * @ppos: position (not valid) 717 * @pipe: pipe to splice to 718 * @len: number of bytes to splice 719 * @flags: splice modifier flags 720 * 721 * Description: 722 * Will read pages from given socket and fill them into a pipe. 723 * 724 **/ 725ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 726 struct pipe_inode_info *pipe, size_t len, 727 unsigned int flags) 728{ 729 struct sock *sk = sock->sk; 730 struct tcp_splice_state tss = { 731 .pipe = pipe, 732 .len = len, 733 .flags = flags, 734 }; 735 long timeo; 736 ssize_t spliced; 737 int ret; 738 739 sock_rps_record_flow(sk); 740 /* 741 * We can't seek on a socket input 742 */ 743 if (unlikely(*ppos)) 744 return -ESPIPE; 745 746 ret = spliced = 0; 747 748 lock_sock(sk); 749 750 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 751 while (tss.len) { 752 ret = __tcp_splice_read(sk, &tss); 753 if (ret < 0) 754 break; 755 else if (!ret) { 756 if (spliced) 757 break; 758 if (sock_flag(sk, SOCK_DONE)) 759 break; 760 if (sk->sk_err) { 761 ret = sock_error(sk); 762 break; 763 } 764 if (sk->sk_shutdown & RCV_SHUTDOWN) 765 break; 766 if (sk->sk_state == TCP_CLOSE) { 767 /* 768 * This occurs when user tries to read 769 * from never connected socket. 770 */ 771 if (!sock_flag(sk, SOCK_DONE)) 772 ret = -ENOTCONN; 773 break; 774 } 775 if (!timeo) { 776 ret = -EAGAIN; 777 break; 778 } 779 sk_wait_data(sk, &timeo); 780 if (signal_pending(current)) { 781 ret = sock_intr_errno(timeo); 782 break; 783 } 784 continue; 785 } 786 tss.len -= ret; 787 spliced += ret; 788 789 if (!timeo) 790 break; 791 release_sock(sk); 792 lock_sock(sk); 793 794 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 795 (sk->sk_shutdown & RCV_SHUTDOWN) || 796 signal_pending(current)) 797 break; 798 } 799 800 release_sock(sk); 801 802 if (spliced) 803 return spliced; 804 805 return ret; 806} 807EXPORT_SYMBOL(tcp_splice_read); 808 809struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 810{ 811 struct sk_buff *skb; 812 813 /* The TCP header must be at least 32-bit aligned. */ 814 size = ALIGN(size, 4); 815 816 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 817 if (skb) { 818 if (sk_wmem_schedule(sk, skb->truesize)) { 819 skb_reserve(skb, sk->sk_prot->max_header); 820 /* 821 * Make sure that we have exactly size bytes 822 * available to the caller, no more, no less. 823 */ 824 skb->reserved_tailroom = skb->end - skb->tail - size; 825 return skb; 826 } 827 __kfree_skb(skb); 828 } else { 829 sk->sk_prot->enter_memory_pressure(sk); 830 sk_stream_moderate_sndbuf(sk); 831 } 832 return NULL; 833} 834 835static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 836 int large_allowed) 837{ 838 struct tcp_sock *tp = tcp_sk(sk); 839 u32 xmit_size_goal, old_size_goal; 840 841 xmit_size_goal = mss_now; 842 843 if (large_allowed && sk_can_gso(sk)) { 844 u32 gso_size, hlen; 845 846 /* Maybe we should/could use sk->sk_prot->max_header here ? */ 847 hlen = inet_csk(sk)->icsk_af_ops->net_header_len + 848 inet_csk(sk)->icsk_ext_hdr_len + 849 tp->tcp_header_len; 850 851 /* Goal is to send at least one packet per ms, 852 * not one big TSO packet every 100 ms. 853 * This preserves ACK clocking and is consistent 854 * with tcp_tso_should_defer() heuristic. 855 */ 856 gso_size = sk->sk_pacing_rate / (2 * MSEC_PER_SEC); 857 gso_size = max_t(u32, gso_size, 858 sysctl_tcp_min_tso_segs * mss_now); 859 860 xmit_size_goal = min_t(u32, gso_size, 861 sk->sk_gso_max_size - 1 - hlen); 862 863 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal); 864 865 /* We try hard to avoid divides here */ 866 old_size_goal = tp->xmit_size_goal_segs * mss_now; 867 868 if (likely(old_size_goal <= xmit_size_goal && 869 old_size_goal + mss_now > xmit_size_goal)) { 870 xmit_size_goal = old_size_goal; 871 } else { 872 tp->xmit_size_goal_segs = 873 min_t(u16, xmit_size_goal / mss_now, 874 sk->sk_gso_max_segs); 875 xmit_size_goal = tp->xmit_size_goal_segs * mss_now; 876 } 877 } 878 879 return max(xmit_size_goal, mss_now); 880} 881 882static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 883{ 884 int mss_now; 885 886 mss_now = tcp_current_mss(sk); 887 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 888 889 return mss_now; 890} 891 892static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 893 size_t size, int flags) 894{ 895 struct tcp_sock *tp = tcp_sk(sk); 896 int mss_now, size_goal; 897 int err; 898 ssize_t copied; 899 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 900 901 /* Wait for a connection to finish. One exception is TCP Fast Open 902 * (passive side) where data is allowed to be sent before a connection 903 * is fully established. 904 */ 905 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 906 !tcp_passive_fastopen(sk)) { 907 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 908 goto out_err; 909 } 910 911 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 912 913 mss_now = tcp_send_mss(sk, &size_goal, flags); 914 copied = 0; 915 916 err = -EPIPE; 917 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 918 goto out_err; 919 920 while (size > 0) { 921 struct sk_buff *skb = tcp_write_queue_tail(sk); 922 int copy, i; 923 bool can_coalesce; 924 925 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 926new_segment: 927 if (!sk_stream_memory_free(sk)) 928 goto wait_for_sndbuf; 929 930 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 931 if (!skb) 932 goto wait_for_memory; 933 934 skb_entail(sk, skb); 935 copy = size_goal; 936 } 937 938 if (copy > size) 939 copy = size; 940 941 i = skb_shinfo(skb)->nr_frags; 942 can_coalesce = skb_can_coalesce(skb, i, page, offset); 943 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 944 tcp_mark_push(tp, skb); 945 goto new_segment; 946 } 947 if (!sk_wmem_schedule(sk, copy)) 948 goto wait_for_memory; 949 950 if (can_coalesce) { 951 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 952 } else { 953 get_page(page); 954 skb_fill_page_desc(skb, i, page, offset, copy); 955 } 956 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 957 958 skb->len += copy; 959 skb->data_len += copy; 960 skb->truesize += copy; 961 sk->sk_wmem_queued += copy; 962 sk_mem_charge(sk, copy); 963 skb->ip_summed = CHECKSUM_PARTIAL; 964 tp->write_seq += copy; 965 TCP_SKB_CB(skb)->end_seq += copy; 966 skb_shinfo(skb)->gso_segs = 0; 967 968 if (!copied) 969 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 970 971 copied += copy; 972 offset += copy; 973 if (!(size -= copy)) { 974 tcp_tx_timestamp(sk, skb); 975 goto out; 976 } 977 978 if (skb->len < size_goal || (flags & MSG_OOB)) 979 continue; 980 981 if (forced_push(tp)) { 982 tcp_mark_push(tp, skb); 983 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 984 } else if (skb == tcp_send_head(sk)) 985 tcp_push_one(sk, mss_now); 986 continue; 987 988wait_for_sndbuf: 989 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 990wait_for_memory: 991 tcp_push(sk, flags & ~MSG_MORE, mss_now, 992 TCP_NAGLE_PUSH, size_goal); 993 994 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 995 goto do_error; 996 997 mss_now = tcp_send_mss(sk, &size_goal, flags); 998 } 999 1000out: 1001 if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) 1002 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 1003 return copied; 1004 1005do_error: 1006 if (copied) 1007 goto out; 1008out_err: 1009 return sk_stream_error(sk, flags, err); 1010} 1011 1012int tcp_sendpage(struct sock *sk, struct page *page, int offset, 1013 size_t size, int flags) 1014{ 1015 ssize_t res; 1016 1017 if (!(sk->sk_route_caps & NETIF_F_SG) || 1018 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 1019 return sock_no_sendpage(sk->sk_socket, page, offset, size, 1020 flags); 1021 1022 lock_sock(sk); 1023 res = do_tcp_sendpages(sk, page, offset, size, flags); 1024 release_sock(sk); 1025 return res; 1026} 1027EXPORT_SYMBOL(tcp_sendpage); 1028 1029static inline int select_size(const struct sock *sk, bool sg) 1030{ 1031 const struct tcp_sock *tp = tcp_sk(sk); 1032 int tmp = tp->mss_cache; 1033 1034 if (sg) { 1035 if (sk_can_gso(sk)) { 1036 /* Small frames wont use a full page: 1037 * Payload will immediately follow tcp header. 1038 */ 1039 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER); 1040 } else { 1041 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 1042 1043 if (tmp >= pgbreak && 1044 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 1045 tmp = pgbreak; 1046 } 1047 } 1048 1049 return tmp; 1050} 1051 1052void tcp_free_fastopen_req(struct tcp_sock *tp) 1053{ 1054 if (tp->fastopen_req != NULL) { 1055 kfree(tp->fastopen_req); 1056 tp->fastopen_req = NULL; 1057 } 1058} 1059 1060static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, 1061 int *copied, size_t size) 1062{ 1063 struct tcp_sock *tp = tcp_sk(sk); 1064 int err, flags; 1065 1066 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE)) 1067 return -EOPNOTSUPP; 1068 if (tp->fastopen_req != NULL) 1069 return -EALREADY; /* Another Fast Open is in progress */ 1070 1071 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request), 1072 sk->sk_allocation); 1073 if (unlikely(tp->fastopen_req == NULL)) 1074 return -ENOBUFS; 1075 tp->fastopen_req->data = msg; 1076 tp->fastopen_req->size = size; 1077 1078 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; 1079 err = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1080 msg->msg_namelen, flags); 1081 *copied = tp->fastopen_req->copied; 1082 tcp_free_fastopen_req(tp); 1083 return err; 1084} 1085 1086int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1087 size_t size) 1088{ 1089 struct iovec *iov; 1090 struct tcp_sock *tp = tcp_sk(sk); 1091 struct sk_buff *skb; 1092 int iovlen, flags, err, copied = 0; 1093 int mss_now = 0, size_goal, copied_syn = 0, offset = 0; 1094 bool sg; 1095 long timeo; 1096 1097 lock_sock(sk); 1098 1099 flags = msg->msg_flags; 1100 if (flags & MSG_FASTOPEN) { 1101 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size); 1102 if (err == -EINPROGRESS && copied_syn > 0) 1103 goto out; 1104 else if (err) 1105 goto out_err; 1106 offset = copied_syn; 1107 } 1108 1109 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 1110 1111 /* Wait for a connection to finish. One exception is TCP Fast Open 1112 * (passive side) where data is allowed to be sent before a connection 1113 * is fully established. 1114 */ 1115 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 1116 !tcp_passive_fastopen(sk)) { 1117 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 1118 goto do_error; 1119 } 1120 1121 if (unlikely(tp->repair)) { 1122 if (tp->repair_queue == TCP_RECV_QUEUE) { 1123 copied = tcp_send_rcvq(sk, msg, size); 1124 goto out_nopush; 1125 } 1126 1127 err = -EINVAL; 1128 if (tp->repair_queue == TCP_NO_QUEUE) 1129 goto out_err; 1130 1131 /* 'common' sending to sendq */ 1132 } 1133 1134 /* This should be in poll */ 1135 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 1136 1137 mss_now = tcp_send_mss(sk, &size_goal, flags); 1138 1139 /* Ok commence sending. */ 1140 iovlen = msg->msg_iovlen; 1141 iov = msg->msg_iov; 1142 copied = 0; 1143 1144 err = -EPIPE; 1145 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 1146 goto out_err; 1147 1148 sg = !!(sk->sk_route_caps & NETIF_F_SG); 1149 1150 while (--iovlen >= 0) { 1151 size_t seglen = iov->iov_len; 1152 unsigned char __user *from = iov->iov_base; 1153 1154 iov++; 1155 if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */ 1156 if (offset >= seglen) { 1157 offset -= seglen; 1158 continue; 1159 } 1160 seglen -= offset; 1161 from += offset; 1162 offset = 0; 1163 } 1164 1165 while (seglen > 0) { 1166 int copy = 0; 1167 int max = size_goal; 1168 1169 skb = tcp_write_queue_tail(sk); 1170 if (tcp_send_head(sk)) { 1171 if (skb->ip_summed == CHECKSUM_NONE) 1172 max = mss_now; 1173 copy = max - skb->len; 1174 } 1175 1176 if (copy <= 0) { 1177new_segment: 1178 /* Allocate new segment. If the interface is SG, 1179 * allocate skb fitting to single page. 1180 */ 1181 if (!sk_stream_memory_free(sk)) 1182 goto wait_for_sndbuf; 1183 1184 skb = sk_stream_alloc_skb(sk, 1185 select_size(sk, sg), 1186 sk->sk_allocation); 1187 if (!skb) 1188 goto wait_for_memory; 1189 1190 /* 1191 * Check whether we can use HW checksum. 1192 */ 1193 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 1194 skb->ip_summed = CHECKSUM_PARTIAL; 1195 1196 skb_entail(sk, skb); 1197 copy = size_goal; 1198 max = size_goal; 1199 1200 /* All packets are restored as if they have 1201 * already been sent. skb_mstamp isn't set to 1202 * avoid wrong rtt estimation. 1203 */ 1204 if (tp->repair) 1205 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; 1206 } 1207 1208 /* Try to append data to the end of skb. */ 1209 if (copy > seglen) 1210 copy = seglen; 1211 1212 /* Where to copy to? */ 1213 if (skb_availroom(skb) > 0) { 1214 /* We have some space in skb head. Superb! */ 1215 copy = min_t(int, copy, skb_availroom(skb)); 1216 err = skb_add_data_nocache(sk, skb, from, copy); 1217 if (err) 1218 goto do_fault; 1219 } else { 1220 bool merge = true; 1221 int i = skb_shinfo(skb)->nr_frags; 1222 struct page_frag *pfrag = sk_page_frag(sk); 1223 1224 if (!sk_page_frag_refill(sk, pfrag)) 1225 goto wait_for_memory; 1226 1227 if (!skb_can_coalesce(skb, i, pfrag->page, 1228 pfrag->offset)) { 1229 if (i == MAX_SKB_FRAGS || !sg) { 1230 tcp_mark_push(tp, skb); 1231 goto new_segment; 1232 } 1233 merge = false; 1234 } 1235 1236 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1237 1238 if (!sk_wmem_schedule(sk, copy)) 1239 goto wait_for_memory; 1240 1241 err = skb_copy_to_page_nocache(sk, from, skb, 1242 pfrag->page, 1243 pfrag->offset, 1244 copy); 1245 if (err) 1246 goto do_error; 1247 1248 /* Update the skb. */ 1249 if (merge) { 1250 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1251 } else { 1252 skb_fill_page_desc(skb, i, pfrag->page, 1253 pfrag->offset, copy); 1254 get_page(pfrag->page); 1255 } 1256 pfrag->offset += copy; 1257 } 1258 1259 if (!copied) 1260 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1261 1262 tp->write_seq += copy; 1263 TCP_SKB_CB(skb)->end_seq += copy; 1264 skb_shinfo(skb)->gso_segs = 0; 1265 1266 from += copy; 1267 copied += copy; 1268 if ((seglen -= copy) == 0 && iovlen == 0) { 1269 tcp_tx_timestamp(sk, skb); 1270 goto out; 1271 } 1272 1273 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) 1274 continue; 1275 1276 if (forced_push(tp)) { 1277 tcp_mark_push(tp, skb); 1278 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1279 } else if (skb == tcp_send_head(sk)) 1280 tcp_push_one(sk, mss_now); 1281 continue; 1282 1283wait_for_sndbuf: 1284 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1285wait_for_memory: 1286 if (copied) 1287 tcp_push(sk, flags & ~MSG_MORE, mss_now, 1288 TCP_NAGLE_PUSH, size_goal); 1289 1290 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1291 goto do_error; 1292 1293 mss_now = tcp_send_mss(sk, &size_goal, flags); 1294 } 1295 } 1296 1297out: 1298 if (copied) 1299 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 1300out_nopush: 1301 release_sock(sk); 1302 return copied + copied_syn; 1303 1304do_fault: 1305 if (!skb->len) { 1306 tcp_unlink_write_queue(skb, sk); 1307 /* It is the one place in all of TCP, except connection 1308 * reset, where we can be unlinking the send_head. 1309 */ 1310 tcp_check_send_head(sk, skb); 1311 sk_wmem_free_skb(sk, skb); 1312 } 1313 1314do_error: 1315 if (copied + copied_syn) 1316 goto out; 1317out_err: 1318 err = sk_stream_error(sk, flags, err); 1319 release_sock(sk); 1320 return err; 1321} 1322EXPORT_SYMBOL(tcp_sendmsg); 1323 1324/* 1325 * Handle reading urgent data. BSD has very simple semantics for 1326 * this, no blocking and very strange errors 8) 1327 */ 1328 1329static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1330{ 1331 struct tcp_sock *tp = tcp_sk(sk); 1332 1333 /* No URG data to read. */ 1334 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1335 tp->urg_data == TCP_URG_READ) 1336 return -EINVAL; /* Yes this is right ! */ 1337 1338 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1339 return -ENOTCONN; 1340 1341 if (tp->urg_data & TCP_URG_VALID) { 1342 int err = 0; 1343 char c = tp->urg_data; 1344 1345 if (!(flags & MSG_PEEK)) 1346 tp->urg_data = TCP_URG_READ; 1347 1348 /* Read urgent data. */ 1349 msg->msg_flags |= MSG_OOB; 1350 1351 if (len > 0) { 1352 if (!(flags & MSG_TRUNC)) 1353 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1354 len = 1; 1355 } else 1356 msg->msg_flags |= MSG_TRUNC; 1357 1358 return err ? -EFAULT : len; 1359 } 1360 1361 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1362 return 0; 1363 1364 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1365 * the available implementations agree in this case: 1366 * this call should never block, independent of the 1367 * blocking state of the socket. 1368 * Mike <pall@rz.uni-karlsruhe.de> 1369 */ 1370 return -EAGAIN; 1371} 1372 1373static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 1374{ 1375 struct sk_buff *skb; 1376 int copied = 0, err = 0; 1377 1378 /* XXX -- need to support SO_PEEK_OFF */ 1379 1380 skb_queue_walk(&sk->sk_write_queue, skb) { 1381 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len); 1382 if (err) 1383 break; 1384 1385 copied += skb->len; 1386 } 1387 1388 return err ?: copied; 1389} 1390 1391/* Clean up the receive buffer for full frames taken by the user, 1392 * then send an ACK if necessary. COPIED is the number of bytes 1393 * tcp_recvmsg has given to the user so far, it speeds up the 1394 * calculation of whether or not we must ACK for the sake of 1395 * a window update. 1396 */ 1397void tcp_cleanup_rbuf(struct sock *sk, int copied) 1398{ 1399 struct tcp_sock *tp = tcp_sk(sk); 1400 bool time_to_ack = false; 1401 1402 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1403 1404 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1405 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1406 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1407 1408 if (inet_csk_ack_scheduled(sk)) { 1409 const struct inet_connection_sock *icsk = inet_csk(sk); 1410 /* Delayed ACKs frequently hit locked sockets during bulk 1411 * receive. */ 1412 if (icsk->icsk_ack.blocked || 1413 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1414 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1415 /* 1416 * If this read emptied read buffer, we send ACK, if 1417 * connection is not bidirectional, user drained 1418 * receive buffer and there was a small segment 1419 * in queue. 1420 */ 1421 (copied > 0 && 1422 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1423 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1424 !icsk->icsk_ack.pingpong)) && 1425 !atomic_read(&sk->sk_rmem_alloc))) 1426 time_to_ack = true; 1427 } 1428 1429 /* We send an ACK if we can now advertise a non-zero window 1430 * which has been raised "significantly". 1431 * 1432 * Even if window raised up to infinity, do not send window open ACK 1433 * in states, where we will not receive more. It is useless. 1434 */ 1435 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1436 __u32 rcv_window_now = tcp_receive_window(tp); 1437 1438 /* Optimize, __tcp_select_window() is not cheap. */ 1439 if (2*rcv_window_now <= tp->window_clamp) { 1440 __u32 new_window = __tcp_select_window(sk); 1441 1442 /* Send ACK now, if this read freed lots of space 1443 * in our buffer. Certainly, new_window is new window. 1444 * We can advertise it now, if it is not less than current one. 1445 * "Lots" means "at least twice" here. 1446 */ 1447 if (new_window && new_window >= 2 * rcv_window_now) 1448 time_to_ack = true; 1449 } 1450 } 1451 if (time_to_ack) 1452 tcp_send_ack(sk); 1453} 1454 1455static void tcp_prequeue_process(struct sock *sk) 1456{ 1457 struct sk_buff *skb; 1458 struct tcp_sock *tp = tcp_sk(sk); 1459 1460 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1461 1462 /* RX process wants to run with disabled BHs, though it is not 1463 * necessary */ 1464 local_bh_disable(); 1465 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1466 sk_backlog_rcv(sk, skb); 1467 local_bh_enable(); 1468 1469 /* Clear memory counter. */ 1470 tp->ucopy.memory = 0; 1471} 1472 1473#ifdef CONFIG_NET_DMA 1474static void tcp_service_net_dma(struct sock *sk, bool wait) 1475{ 1476 dma_cookie_t done, used; 1477 dma_cookie_t last_issued; 1478 struct tcp_sock *tp = tcp_sk(sk); 1479 1480 if (!tp->ucopy.dma_chan) 1481 return; 1482 1483 last_issued = tp->ucopy.dma_cookie; 1484 dma_async_issue_pending(tp->ucopy.dma_chan); 1485 1486 do { 1487 if (dma_async_is_tx_complete(tp->ucopy.dma_chan, 1488 last_issued, &done, 1489 &used) == DMA_COMPLETE) { 1490 /* Safe to free early-copied skbs now */ 1491 __skb_queue_purge(&sk->sk_async_wait_queue); 1492 break; 1493 } else { 1494 struct sk_buff *skb; 1495 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1496 (dma_async_is_complete(skb->dma_cookie, done, 1497 used) == DMA_COMPLETE)) { 1498 __skb_dequeue(&sk->sk_async_wait_queue); 1499 kfree_skb(skb); 1500 } 1501 } 1502 } while (wait); 1503} 1504#endif 1505 1506static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1507{ 1508 struct sk_buff *skb; 1509 u32 offset; 1510 1511 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) { 1512 offset = seq - TCP_SKB_CB(skb)->seq; 1513 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1514 offset--; 1515 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) { 1516 *off = offset; 1517 return skb; 1518 } 1519 /* This looks weird, but this can happen if TCP collapsing 1520 * splitted a fat GRO packet, while we released socket lock 1521 * in skb_splice_bits() 1522 */ 1523 sk_eat_skb(sk, skb, false); 1524 } 1525 return NULL; 1526} 1527 1528/* 1529 * This routine provides an alternative to tcp_recvmsg() for routines 1530 * that would like to handle copying from skbuffs directly in 'sendfile' 1531 * fashion. 1532 * Note: 1533 * - It is assumed that the socket was locked by the caller. 1534 * - The routine does not block. 1535 * - At present, there is no support for reading OOB data 1536 * or for 'peeking' the socket using this routine 1537 * (although both would be easy to implement). 1538 */ 1539int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1540 sk_read_actor_t recv_actor) 1541{ 1542 struct sk_buff *skb; 1543 struct tcp_sock *tp = tcp_sk(sk); 1544 u32 seq = tp->copied_seq; 1545 u32 offset; 1546 int copied = 0; 1547 1548 if (sk->sk_state == TCP_LISTEN) 1549 return -ENOTCONN; 1550 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1551 if (offset < skb->len) { 1552 int used; 1553 size_t len; 1554 1555 len = skb->len - offset; 1556 /* Stop reading if we hit a patch of urgent data */ 1557 if (tp->urg_data) { 1558 u32 urg_offset = tp->urg_seq - seq; 1559 if (urg_offset < len) 1560 len = urg_offset; 1561 if (!len) 1562 break; 1563 } 1564 used = recv_actor(desc, skb, offset, len); 1565 if (used <= 0) { 1566 if (!copied) 1567 copied = used; 1568 break; 1569 } else if (used <= len) { 1570 seq += used; 1571 copied += used; 1572 offset += used; 1573 } 1574 /* If recv_actor drops the lock (e.g. TCP splice 1575 * receive) the skb pointer might be invalid when 1576 * getting here: tcp_collapse might have deleted it 1577 * while aggregating skbs from the socket queue. 1578 */ 1579 skb = tcp_recv_skb(sk, seq - 1, &offset); 1580 if (!skb) 1581 break; 1582 /* TCP coalescing might have appended data to the skb. 1583 * Try to splice more frags 1584 */ 1585 if (offset + 1 != skb->len) 1586 continue; 1587 } 1588 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { 1589 sk_eat_skb(sk, skb, false); 1590 ++seq; 1591 break; 1592 } 1593 sk_eat_skb(sk, skb, false); 1594 if (!desc->count) 1595 break; 1596 tp->copied_seq = seq; 1597 } 1598 tp->copied_seq = seq; 1599 1600 tcp_rcv_space_adjust(sk); 1601 1602 /* Clean up data we have read: This will do ACK frames. */ 1603 if (copied > 0) { 1604 tcp_recv_skb(sk, seq, &offset); 1605 tcp_cleanup_rbuf(sk, copied); 1606 } 1607 return copied; 1608} 1609EXPORT_SYMBOL(tcp_read_sock); 1610 1611/* 1612 * This routine copies from a sock struct into the user buffer. 1613 * 1614 * Technical note: in 2.3 we work on _locked_ socket, so that 1615 * tricks with *seq access order and skb->users are not required. 1616 * Probably, code can be easily improved even more. 1617 */ 1618 1619int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1620 size_t len, int nonblock, int flags, int *addr_len) 1621{ 1622 struct tcp_sock *tp = tcp_sk(sk); 1623 int copied = 0; 1624 u32 peek_seq; 1625 u32 *seq; 1626 unsigned long used; 1627 int err; 1628 int target; /* Read at least this many bytes */ 1629 long timeo; 1630 struct task_struct *user_recv = NULL; 1631 bool copied_early = false; 1632 struct sk_buff *skb; 1633 u32 urg_hole = 0; 1634 1635 if (unlikely(flags & MSG_ERRQUEUE)) 1636 return ip_recv_error(sk, msg, len, addr_len); 1637 1638 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) && 1639 (sk->sk_state == TCP_ESTABLISHED)) 1640 sk_busy_loop(sk, nonblock); 1641 1642 lock_sock(sk); 1643 1644 err = -ENOTCONN; 1645 if (sk->sk_state == TCP_LISTEN) 1646 goto out; 1647 1648 timeo = sock_rcvtimeo(sk, nonblock); 1649 1650 /* Urgent data needs to be handled specially. */ 1651 if (flags & MSG_OOB) 1652 goto recv_urg; 1653 1654 if (unlikely(tp->repair)) { 1655 err = -EPERM; 1656 if (!(flags & MSG_PEEK)) 1657 goto out; 1658 1659 if (tp->repair_queue == TCP_SEND_QUEUE) 1660 goto recv_sndq; 1661 1662 err = -EINVAL; 1663 if (tp->repair_queue == TCP_NO_QUEUE) 1664 goto out; 1665 1666 /* 'common' recv queue MSG_PEEK-ing */ 1667 } 1668 1669 seq = &tp->copied_seq; 1670 if (flags & MSG_PEEK) { 1671 peek_seq = tp->copied_seq; 1672 seq = &peek_seq; 1673 } 1674 1675 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1676 1677#ifdef CONFIG_NET_DMA 1678 tp->ucopy.dma_chan = NULL; 1679 preempt_disable(); 1680 skb = skb_peek_tail(&sk->sk_receive_queue); 1681 { 1682 int available = 0; 1683 1684 if (skb) 1685 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1686 if ((available < target) && 1687 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1688 !sysctl_tcp_low_latency && 1689 net_dma_find_channel()) { 1690 preempt_enable(); 1691 tp->ucopy.pinned_list = 1692 dma_pin_iovec_pages(msg->msg_iov, len); 1693 } else { 1694 preempt_enable(); 1695 } 1696 } 1697#endif 1698 1699 do { 1700 u32 offset; 1701 1702 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1703 if (tp->urg_data && tp->urg_seq == *seq) { 1704 if (copied) 1705 break; 1706 if (signal_pending(current)) { 1707 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1708 break; 1709 } 1710 } 1711 1712 /* Next get a buffer. */ 1713 1714 skb_queue_walk(&sk->sk_receive_queue, skb) { 1715 /* Now that we have two receive queues this 1716 * shouldn't happen. 1717 */ 1718 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1719 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1720 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1721 flags)) 1722 break; 1723 1724 offset = *seq - TCP_SKB_CB(skb)->seq; 1725 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1726 offset--; 1727 if (offset < skb->len) 1728 goto found_ok_skb; 1729 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1730 goto found_fin_ok; 1731 WARN(!(flags & MSG_PEEK), 1732 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1733 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1734 } 1735 1736 /* Well, if we have backlog, try to process it now yet. */ 1737 1738 if (copied >= target && !sk->sk_backlog.tail) 1739 break; 1740 1741 if (copied) { 1742 if (sk->sk_err || 1743 sk->sk_state == TCP_CLOSE || 1744 (sk->sk_shutdown & RCV_SHUTDOWN) || 1745 !timeo || 1746 signal_pending(current)) 1747 break; 1748 } else { 1749 if (sock_flag(sk, SOCK_DONE)) 1750 break; 1751 1752 if (sk->sk_err) { 1753 copied = sock_error(sk); 1754 break; 1755 } 1756 1757 if (sk->sk_shutdown & RCV_SHUTDOWN) 1758 break; 1759 1760 if (sk->sk_state == TCP_CLOSE) { 1761 if (!sock_flag(sk, SOCK_DONE)) { 1762 /* This occurs when user tries to read 1763 * from never connected socket. 1764 */ 1765 copied = -ENOTCONN; 1766 break; 1767 } 1768 break; 1769 } 1770 1771 if (!timeo) { 1772 copied = -EAGAIN; 1773 break; 1774 } 1775 1776 if (signal_pending(current)) { 1777 copied = sock_intr_errno(timeo); 1778 break; 1779 } 1780 } 1781 1782 tcp_cleanup_rbuf(sk, copied); 1783 1784 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1785 /* Install new reader */ 1786 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1787 user_recv = current; 1788 tp->ucopy.task = user_recv; 1789 tp->ucopy.iov = msg->msg_iov; 1790 } 1791 1792 tp->ucopy.len = len; 1793 1794 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1795 !(flags & (MSG_PEEK | MSG_TRUNC))); 1796 1797 /* Ugly... If prequeue is not empty, we have to 1798 * process it before releasing socket, otherwise 1799 * order will be broken at second iteration. 1800 * More elegant solution is required!!! 1801 * 1802 * Look: we have the following (pseudo)queues: 1803 * 1804 * 1. packets in flight 1805 * 2. backlog 1806 * 3. prequeue 1807 * 4. receive_queue 1808 * 1809 * Each queue can be processed only if the next ones 1810 * are empty. At this point we have empty receive_queue. 1811 * But prequeue _can_ be not empty after 2nd iteration, 1812 * when we jumped to start of loop because backlog 1813 * processing added something to receive_queue. 1814 * We cannot release_sock(), because backlog contains 1815 * packets arrived _after_ prequeued ones. 1816 * 1817 * Shortly, algorithm is clear --- to process all 1818 * the queues in order. We could make it more directly, 1819 * requeueing packets from backlog to prequeue, if 1820 * is not empty. It is more elegant, but eats cycles, 1821 * unfortunately. 1822 */ 1823 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1824 goto do_prequeue; 1825 1826 /* __ Set realtime policy in scheduler __ */ 1827 } 1828 1829#ifdef CONFIG_NET_DMA 1830 if (tp->ucopy.dma_chan) { 1831 if (tp->rcv_wnd == 0 && 1832 !skb_queue_empty(&sk->sk_async_wait_queue)) { 1833 tcp_service_net_dma(sk, true); 1834 tcp_cleanup_rbuf(sk, copied); 1835 } else 1836 dma_async_issue_pending(tp->ucopy.dma_chan); 1837 } 1838#endif 1839 if (copied >= target) { 1840 /* Do not sleep, just process backlog. */ 1841 release_sock(sk); 1842 lock_sock(sk); 1843 } else 1844 sk_wait_data(sk, &timeo); 1845 1846#ifdef CONFIG_NET_DMA 1847 tcp_service_net_dma(sk, false); /* Don't block */ 1848 tp->ucopy.wakeup = 0; 1849#endif 1850 1851 if (user_recv) { 1852 int chunk; 1853 1854 /* __ Restore normal policy in scheduler __ */ 1855 1856 if ((chunk = len - tp->ucopy.len) != 0) { 1857 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1858 len -= chunk; 1859 copied += chunk; 1860 } 1861 1862 if (tp->rcv_nxt == tp->copied_seq && 1863 !skb_queue_empty(&tp->ucopy.prequeue)) { 1864do_prequeue: 1865 tcp_prequeue_process(sk); 1866 1867 if ((chunk = len - tp->ucopy.len) != 0) { 1868 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1869 len -= chunk; 1870 copied += chunk; 1871 } 1872 } 1873 } 1874 if ((flags & MSG_PEEK) && 1875 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1876 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n", 1877 current->comm, 1878 task_pid_nr(current)); 1879 peek_seq = tp->copied_seq; 1880 } 1881 continue; 1882 1883 found_ok_skb: 1884 /* Ok so how much can we use? */ 1885 used = skb->len - offset; 1886 if (len < used) 1887 used = len; 1888 1889 /* Do we have urgent data here? */ 1890 if (tp->urg_data) { 1891 u32 urg_offset = tp->urg_seq - *seq; 1892 if (urg_offset < used) { 1893 if (!urg_offset) { 1894 if (!sock_flag(sk, SOCK_URGINLINE)) { 1895 ++*seq; 1896 urg_hole++; 1897 offset++; 1898 used--; 1899 if (!used) 1900 goto skip_copy; 1901 } 1902 } else 1903 used = urg_offset; 1904 } 1905 } 1906 1907 if (!(flags & MSG_TRUNC)) { 1908#ifdef CONFIG_NET_DMA 1909 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1910 tp->ucopy.dma_chan = net_dma_find_channel(); 1911 1912 if (tp->ucopy.dma_chan) { 1913 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1914 tp->ucopy.dma_chan, skb, offset, 1915 msg->msg_iov, used, 1916 tp->ucopy.pinned_list); 1917 1918 if (tp->ucopy.dma_cookie < 0) { 1919 1920 pr_alert("%s: dma_cookie < 0\n", 1921 __func__); 1922 1923 /* Exception. Bailout! */ 1924 if (!copied) 1925 copied = -EFAULT; 1926 break; 1927 } 1928 1929 dma_async_issue_pending(tp->ucopy.dma_chan); 1930 1931 if ((offset + used) == skb->len) 1932 copied_early = true; 1933 1934 } else 1935#endif 1936 { 1937 err = skb_copy_datagram_iovec(skb, offset, 1938 msg->msg_iov, used); 1939 if (err) { 1940 /* Exception. Bailout! */ 1941 if (!copied) 1942 copied = -EFAULT; 1943 break; 1944 } 1945 } 1946 } 1947 1948 *seq += used; 1949 copied += used; 1950 len -= used; 1951 1952 tcp_rcv_space_adjust(sk); 1953 1954skip_copy: 1955 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1956 tp->urg_data = 0; 1957 tcp_fast_path_check(sk); 1958 } 1959 if (used + offset < skb->len) 1960 continue; 1961 1962 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1963 goto found_fin_ok; 1964 if (!(flags & MSG_PEEK)) { 1965 sk_eat_skb(sk, skb, copied_early); 1966 copied_early = false; 1967 } 1968 continue; 1969 1970 found_fin_ok: 1971 /* Process the FIN. */ 1972 ++*seq; 1973 if (!(flags & MSG_PEEK)) { 1974 sk_eat_skb(sk, skb, copied_early); 1975 copied_early = false; 1976 } 1977 break; 1978 } while (len > 0); 1979 1980 if (user_recv) { 1981 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1982 int chunk; 1983 1984 tp->ucopy.len = copied > 0 ? len : 0; 1985 1986 tcp_prequeue_process(sk); 1987 1988 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1989 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1990 len -= chunk; 1991 copied += chunk; 1992 } 1993 } 1994 1995 tp->ucopy.task = NULL; 1996 tp->ucopy.len = 0; 1997 } 1998 1999#ifdef CONFIG_NET_DMA 2000 tcp_service_net_dma(sk, true); /* Wait for queue to drain */ 2001 tp->ucopy.dma_chan = NULL; 2002 2003 if (tp->ucopy.pinned_list) { 2004 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 2005 tp->ucopy.pinned_list = NULL; 2006 } 2007#endif 2008 2009 /* According to UNIX98, msg_name/msg_namelen are ignored 2010 * on connected socket. I was just happy when found this 8) --ANK 2011 */ 2012 2013 /* Clean up data we have read: This will do ACK frames. */ 2014 tcp_cleanup_rbuf(sk, copied); 2015 2016 release_sock(sk); 2017 return copied; 2018 2019out: 2020 release_sock(sk); 2021 return err; 2022 2023recv_urg: 2024 err = tcp_recv_urg(sk, msg, len, flags); 2025 goto out; 2026 2027recv_sndq: 2028 err = tcp_peek_sndq(sk, msg, len); 2029 goto out; 2030} 2031EXPORT_SYMBOL(tcp_recvmsg); 2032 2033void tcp_set_state(struct sock *sk, int state) 2034{ 2035 int oldstate = sk->sk_state; 2036 2037 switch (state) { 2038 case TCP_ESTABLISHED: 2039 if (oldstate != TCP_ESTABLISHED) 2040 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 2041 break; 2042 2043 case TCP_CLOSE: 2044 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 2045 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 2046 2047 sk->sk_prot->unhash(sk); 2048 if (inet_csk(sk)->icsk_bind_hash && 2049 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 2050 inet_put_port(sk); 2051 /* fall through */ 2052 default: 2053 if (oldstate == TCP_ESTABLISHED) 2054 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 2055 } 2056 2057 /* Change state AFTER socket is unhashed to avoid closed 2058 * socket sitting in hash tables. 2059 */ 2060 sk->sk_state = state; 2061 2062#ifdef STATE_TRACE 2063 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 2064#endif 2065} 2066EXPORT_SYMBOL_GPL(tcp_set_state); 2067 2068/* 2069 * State processing on a close. This implements the state shift for 2070 * sending our FIN frame. Note that we only send a FIN for some 2071 * states. A shutdown() may have already sent the FIN, or we may be 2072 * closed. 2073 */ 2074 2075static const unsigned char new_state[16] = { 2076 /* current state: new state: action: */ 2077 /* (Invalid) */ TCP_CLOSE, 2078 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2079 /* TCP_SYN_SENT */ TCP_CLOSE, 2080 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2081 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 2082 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 2083 /* TCP_TIME_WAIT */ TCP_CLOSE, 2084 /* TCP_CLOSE */ TCP_CLOSE, 2085 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 2086 /* TCP_LAST_ACK */ TCP_LAST_ACK, 2087 /* TCP_LISTEN */ TCP_CLOSE, 2088 /* TCP_CLOSING */ TCP_CLOSING, 2089}; 2090 2091static int tcp_close_state(struct sock *sk) 2092{ 2093 int next = (int)new_state[sk->sk_state]; 2094 int ns = next & TCP_STATE_MASK; 2095 2096 tcp_set_state(sk, ns); 2097 2098 return next & TCP_ACTION_FIN; 2099} 2100 2101/* 2102 * Shutdown the sending side of a connection. Much like close except 2103 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 2104 */ 2105 2106void tcp_shutdown(struct sock *sk, int how) 2107{ 2108 /* We need to grab some memory, and put together a FIN, 2109 * and then put it into the queue to be sent. 2110 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 2111 */ 2112 if (!(how & SEND_SHUTDOWN)) 2113 return; 2114 2115 /* If we've already sent a FIN, or it's a closed state, skip this. */ 2116 if ((1 << sk->sk_state) & 2117 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 2118 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 2119 /* Clear out any half completed packets. FIN if needed. */ 2120 if (tcp_close_state(sk)) 2121 tcp_send_fin(sk); 2122 } 2123} 2124EXPORT_SYMBOL(tcp_shutdown); 2125 2126bool tcp_check_oom(struct sock *sk, int shift) 2127{ 2128 bool too_many_orphans, out_of_socket_memory; 2129 2130 too_many_orphans = tcp_too_many_orphans(sk, shift); 2131 out_of_socket_memory = tcp_out_of_memory(sk); 2132 2133 if (too_many_orphans) 2134 net_info_ratelimited("too many orphaned sockets\n"); 2135 if (out_of_socket_memory) 2136 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n"); 2137 return too_many_orphans || out_of_socket_memory; 2138} 2139 2140void tcp_close(struct sock *sk, long timeout) 2141{ 2142 struct sk_buff *skb; 2143 int data_was_unread = 0; 2144 int state; 2145 2146 lock_sock(sk); 2147 sk->sk_shutdown = SHUTDOWN_MASK; 2148 2149 if (sk->sk_state == TCP_LISTEN) { 2150 tcp_set_state(sk, TCP_CLOSE); 2151 2152 /* Special case. */ 2153 inet_csk_listen_stop(sk); 2154 2155 goto adjudge_to_death; 2156 } 2157 2158 /* We need to flush the recv. buffs. We do this only on the 2159 * descriptor close, not protocol-sourced closes, because the 2160 * reader process may not have drained the data yet! 2161 */ 2162 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 2163 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq; 2164 2165 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 2166 len--; 2167 data_was_unread += len; 2168 __kfree_skb(skb); 2169 } 2170 2171 sk_mem_reclaim(sk); 2172 2173 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 2174 if (sk->sk_state == TCP_CLOSE) 2175 goto adjudge_to_death; 2176 2177 /* As outlined in RFC 2525, section 2.17, we send a RST here because 2178 * data was lost. To witness the awful effects of the old behavior of 2179 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 2180 * GET in an FTP client, suspend the process, wait for the client to 2181 * advertise a zero window, then kill -9 the FTP client, wheee... 2182 * Note: timeout is always zero in such a case. 2183 */ 2184 if (unlikely(tcp_sk(sk)->repair)) { 2185 sk->sk_prot->disconnect(sk, 0); 2186 } else if (data_was_unread) { 2187 /* Unread data was tossed, zap the connection. */ 2188 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 2189 tcp_set_state(sk, TCP_CLOSE); 2190 tcp_send_active_reset(sk, sk->sk_allocation); 2191 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 2192 /* Check zero linger _after_ checking for unread data. */ 2193 sk->sk_prot->disconnect(sk, 0); 2194 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 2195 } else if (tcp_close_state(sk)) { 2196 /* We FIN if the application ate all the data before 2197 * zapping the connection. 2198 */ 2199 2200 /* RED-PEN. Formally speaking, we have broken TCP state 2201 * machine. State transitions: 2202 * 2203 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 2204 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 2205 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 2206 * 2207 * are legal only when FIN has been sent (i.e. in window), 2208 * rather than queued out of window. Purists blame. 2209 * 2210 * F.e. "RFC state" is ESTABLISHED, 2211 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 2212 * 2213 * The visible declinations are that sometimes 2214 * we enter time-wait state, when it is not required really 2215 * (harmless), do not send active resets, when they are 2216 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 2217 * they look as CLOSING or LAST_ACK for Linux) 2218 * Probably, I missed some more holelets. 2219 * --ANK 2220 * XXX (TFO) - To start off we don't support SYN+ACK+FIN 2221 * in a single packet! (May consider it later but will 2222 * probably need API support or TCP_CORK SYN-ACK until 2223 * data is written and socket is closed.) 2224 */ 2225 tcp_send_fin(sk); 2226 } 2227 2228 sk_stream_wait_close(sk, timeout); 2229 2230adjudge_to_death: 2231 state = sk->sk_state; 2232 sock_hold(sk); 2233 sock_orphan(sk); 2234 2235 /* It is the last release_sock in its life. It will remove backlog. */ 2236 release_sock(sk); 2237 2238 2239 /* Now socket is owned by kernel and we acquire BH lock 2240 to finish close. No need to check for user refs. 2241 */ 2242 local_bh_disable(); 2243 bh_lock_sock(sk); 2244 WARN_ON(sock_owned_by_user(sk)); 2245 2246 percpu_counter_inc(sk->sk_prot->orphan_count); 2247 2248 /* Have we already been destroyed by a softirq or backlog? */ 2249 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 2250 goto out; 2251 2252 /* This is a (useful) BSD violating of the RFC. There is a 2253 * problem with TCP as specified in that the other end could 2254 * keep a socket open forever with no application left this end. 2255 * We use a 1 minute timeout (about the same as BSD) then kill 2256 * our end. If they send after that then tough - BUT: long enough 2257 * that we won't make the old 4*rto = almost no time - whoops 2258 * reset mistake. 2259 * 2260 * Nope, it was not mistake. It is really desired behaviour 2261 * f.e. on http servers, when such sockets are useless, but 2262 * consume significant resources. Let's do it with special 2263 * linger2 option. --ANK 2264 */ 2265 2266 if (sk->sk_state == TCP_FIN_WAIT2) { 2267 struct tcp_sock *tp = tcp_sk(sk); 2268 if (tp->linger2 < 0) { 2269 tcp_set_state(sk, TCP_CLOSE); 2270 tcp_send_active_reset(sk, GFP_ATOMIC); 2271 NET_INC_STATS_BH(sock_net(sk), 2272 LINUX_MIB_TCPABORTONLINGER); 2273 } else { 2274 const int tmo = tcp_fin_time(sk); 2275 2276 if (tmo > TCP_TIMEWAIT_LEN) { 2277 inet_csk_reset_keepalive_timer(sk, 2278 tmo - TCP_TIMEWAIT_LEN); 2279 } else { 2280 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2281 goto out; 2282 } 2283 } 2284 } 2285 if (sk->sk_state != TCP_CLOSE) { 2286 sk_mem_reclaim(sk); 2287 if (tcp_check_oom(sk, 0)) { 2288 tcp_set_state(sk, TCP_CLOSE); 2289 tcp_send_active_reset(sk, GFP_ATOMIC); 2290 NET_INC_STATS_BH(sock_net(sk), 2291 LINUX_MIB_TCPABORTONMEMORY); 2292 } 2293 } 2294 2295 if (sk->sk_state == TCP_CLOSE) { 2296 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2297 /* We could get here with a non-NULL req if the socket is 2298 * aborted (e.g., closed with unread data) before 3WHS 2299 * finishes. 2300 */ 2301 if (req != NULL) 2302 reqsk_fastopen_remove(sk, req, false); 2303 inet_csk_destroy_sock(sk); 2304 } 2305 /* Otherwise, socket is reprieved until protocol close. */ 2306 2307out: 2308 bh_unlock_sock(sk); 2309 local_bh_enable(); 2310 sock_put(sk); 2311} 2312EXPORT_SYMBOL(tcp_close); 2313 2314/* These states need RST on ABORT according to RFC793 */ 2315 2316static inline bool tcp_need_reset(int state) 2317{ 2318 return (1 << state) & 2319 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2320 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2321} 2322 2323int tcp_disconnect(struct sock *sk, int flags) 2324{ 2325 struct inet_sock *inet = inet_sk(sk); 2326 struct inet_connection_sock *icsk = inet_csk(sk); 2327 struct tcp_sock *tp = tcp_sk(sk); 2328 int err = 0; 2329 int old_state = sk->sk_state; 2330 2331 if (old_state != TCP_CLOSE) 2332 tcp_set_state(sk, TCP_CLOSE); 2333 2334 /* ABORT function of RFC793 */ 2335 if (old_state == TCP_LISTEN) { 2336 inet_csk_listen_stop(sk); 2337 } else if (unlikely(tp->repair)) { 2338 sk->sk_err = ECONNABORTED; 2339 } else if (tcp_need_reset(old_state) || 2340 (tp->snd_nxt != tp->write_seq && 2341 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2342 /* The last check adjusts for discrepancy of Linux wrt. RFC 2343 * states 2344 */ 2345 tcp_send_active_reset(sk, gfp_any()); 2346 sk->sk_err = ECONNRESET; 2347 } else if (old_state == TCP_SYN_SENT) 2348 sk->sk_err = ECONNRESET; 2349 2350 tcp_clear_xmit_timers(sk); 2351 __skb_queue_purge(&sk->sk_receive_queue); 2352 tcp_write_queue_purge(sk); 2353 __skb_queue_purge(&tp->out_of_order_queue); 2354#ifdef CONFIG_NET_DMA 2355 __skb_queue_purge(&sk->sk_async_wait_queue); 2356#endif 2357 2358 inet->inet_dport = 0; 2359 2360 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2361 inet_reset_saddr(sk); 2362 2363 sk->sk_shutdown = 0; 2364 sock_reset_flag(sk, SOCK_DONE); 2365 tp->srtt_us = 0; 2366 if ((tp->write_seq += tp->max_window + 2) == 0) 2367 tp->write_seq = 1; 2368 icsk->icsk_backoff = 0; 2369 tp->snd_cwnd = 2; 2370 icsk->icsk_probes_out = 0; 2371 tp->packets_out = 0; 2372 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2373 tp->snd_cwnd_cnt = 0; 2374 tp->window_clamp = 0; 2375 tcp_set_ca_state(sk, TCP_CA_Open); 2376 tcp_clear_retrans(tp); 2377 inet_csk_delack_init(sk); 2378 tcp_init_send_head(sk); 2379 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2380 __sk_dst_reset(sk); 2381 2382 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2383 2384 sk->sk_error_report(sk); 2385 return err; 2386} 2387EXPORT_SYMBOL(tcp_disconnect); 2388 2389void tcp_sock_destruct(struct sock *sk) 2390{ 2391 inet_sock_destruct(sk); 2392 2393 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq); 2394} 2395 2396static inline bool tcp_can_repair_sock(const struct sock *sk) 2397{ 2398 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) && 2399 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED)); 2400} 2401 2402static int tcp_repair_options_est(struct tcp_sock *tp, 2403 struct tcp_repair_opt __user *optbuf, unsigned int len) 2404{ 2405 struct tcp_repair_opt opt; 2406 2407 while (len >= sizeof(opt)) { 2408 if (copy_from_user(&opt, optbuf, sizeof(opt))) 2409 return -EFAULT; 2410 2411 optbuf++; 2412 len -= sizeof(opt); 2413 2414 switch (opt.opt_code) { 2415 case TCPOPT_MSS: 2416 tp->rx_opt.mss_clamp = opt.opt_val; 2417 break; 2418 case TCPOPT_WINDOW: 2419 { 2420 u16 snd_wscale = opt.opt_val & 0xFFFF; 2421 u16 rcv_wscale = opt.opt_val >> 16; 2422 2423 if (snd_wscale > 14 || rcv_wscale > 14) 2424 return -EFBIG; 2425 2426 tp->rx_opt.snd_wscale = snd_wscale; 2427 tp->rx_opt.rcv_wscale = rcv_wscale; 2428 tp->rx_opt.wscale_ok = 1; 2429 } 2430 break; 2431 case TCPOPT_SACK_PERM: 2432 if (opt.opt_val != 0) 2433 return -EINVAL; 2434 2435 tp->rx_opt.sack_ok |= TCP_SACK_SEEN; 2436 if (sysctl_tcp_fack) 2437 tcp_enable_fack(tp); 2438 break; 2439 case TCPOPT_TIMESTAMP: 2440 if (opt.opt_val != 0) 2441 return -EINVAL; 2442 2443 tp->rx_opt.tstamp_ok = 1; 2444 break; 2445 } 2446 } 2447 2448 return 0; 2449} 2450 2451/* 2452 * Socket option code for TCP. 2453 */ 2454static int do_tcp_setsockopt(struct sock *sk, int level, 2455 int optname, char __user *optval, unsigned int optlen) 2456{ 2457 struct tcp_sock *tp = tcp_sk(sk); 2458 struct inet_connection_sock *icsk = inet_csk(sk); 2459 int val; 2460 int err = 0; 2461 2462 /* These are data/string values, all the others are ints */ 2463 switch (optname) { 2464 case TCP_CONGESTION: { 2465 char name[TCP_CA_NAME_MAX]; 2466 2467 if (optlen < 1) 2468 return -EINVAL; 2469 2470 val = strncpy_from_user(name, optval, 2471 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2472 if (val < 0) 2473 return -EFAULT; 2474 name[val] = 0; 2475 2476 lock_sock(sk); 2477 err = tcp_set_congestion_control(sk, name); 2478 release_sock(sk); 2479 return err; 2480 } 2481 default: 2482 /* fallthru */ 2483 break; 2484 } 2485 2486 if (optlen < sizeof(int)) 2487 return -EINVAL; 2488 2489 if (get_user(val, (int __user *)optval)) 2490 return -EFAULT; 2491 2492 lock_sock(sk); 2493 2494 switch (optname) { 2495 case TCP_MAXSEG: 2496 /* Values greater than interface MTU won't take effect. However 2497 * at the point when this call is done we typically don't yet 2498 * know which interface is going to be used */ 2499 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2500 err = -EINVAL; 2501 break; 2502 } 2503 tp->rx_opt.user_mss = val; 2504 break; 2505 2506 case TCP_NODELAY: 2507 if (val) { 2508 /* TCP_NODELAY is weaker than TCP_CORK, so that 2509 * this option on corked socket is remembered, but 2510 * it is not activated until cork is cleared. 2511 * 2512 * However, when TCP_NODELAY is set we make 2513 * an explicit push, which overrides even TCP_CORK 2514 * for currently queued segments. 2515 */ 2516 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2517 tcp_push_pending_frames(sk); 2518 } else { 2519 tp->nonagle &= ~TCP_NAGLE_OFF; 2520 } 2521 break; 2522 2523 case TCP_THIN_LINEAR_TIMEOUTS: 2524 if (val < 0 || val > 1) 2525 err = -EINVAL; 2526 else 2527 tp->thin_lto = val; 2528 break; 2529 2530 case TCP_THIN_DUPACK: 2531 if (val < 0 || val > 1) 2532 err = -EINVAL; 2533 else { 2534 tp->thin_dupack = val; 2535 if (tp->thin_dupack) 2536 tcp_disable_early_retrans(tp); 2537 } 2538 break; 2539 2540 case TCP_REPAIR: 2541 if (!tcp_can_repair_sock(sk)) 2542 err = -EPERM; 2543 else if (val == 1) { 2544 tp->repair = 1; 2545 sk->sk_reuse = SK_FORCE_REUSE; 2546 tp->repair_queue = TCP_NO_QUEUE; 2547 } else if (val == 0) { 2548 tp->repair = 0; 2549 sk->sk_reuse = SK_NO_REUSE; 2550 tcp_send_window_probe(sk); 2551 } else 2552 err = -EINVAL; 2553 2554 break; 2555 2556 case TCP_REPAIR_QUEUE: 2557 if (!tp->repair) 2558 err = -EPERM; 2559 else if (val < TCP_QUEUES_NR) 2560 tp->repair_queue = val; 2561 else 2562 err = -EINVAL; 2563 break; 2564 2565 case TCP_QUEUE_SEQ: 2566 if (sk->sk_state != TCP_CLOSE) 2567 err = -EPERM; 2568 else if (tp->repair_queue == TCP_SEND_QUEUE) 2569 tp->write_seq = val; 2570 else if (tp->repair_queue == TCP_RECV_QUEUE) 2571 tp->rcv_nxt = val; 2572 else 2573 err = -EINVAL; 2574 break; 2575 2576 case TCP_REPAIR_OPTIONS: 2577 if (!tp->repair) 2578 err = -EINVAL; 2579 else if (sk->sk_state == TCP_ESTABLISHED) 2580 err = tcp_repair_options_est(tp, 2581 (struct tcp_repair_opt __user *)optval, 2582 optlen); 2583 else 2584 err = -EPERM; 2585 break; 2586 2587 case TCP_CORK: 2588 /* When set indicates to always queue non-full frames. 2589 * Later the user clears this option and we transmit 2590 * any pending partial frames in the queue. This is 2591 * meant to be used alongside sendfile() to get properly 2592 * filled frames when the user (for example) must write 2593 * out headers with a write() call first and then use 2594 * sendfile to send out the data parts. 2595 * 2596 * TCP_CORK can be set together with TCP_NODELAY and it is 2597 * stronger than TCP_NODELAY. 2598 */ 2599 if (val) { 2600 tp->nonagle |= TCP_NAGLE_CORK; 2601 } else { 2602 tp->nonagle &= ~TCP_NAGLE_CORK; 2603 if (tp->nonagle&TCP_NAGLE_OFF) 2604 tp->nonagle |= TCP_NAGLE_PUSH; 2605 tcp_push_pending_frames(sk); 2606 } 2607 break; 2608 2609 case TCP_KEEPIDLE: 2610 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2611 err = -EINVAL; 2612 else { 2613 tp->keepalive_time = val * HZ; 2614 if (sock_flag(sk, SOCK_KEEPOPEN) && 2615 !((1 << sk->sk_state) & 2616 (TCPF_CLOSE | TCPF_LISTEN))) { 2617 u32 elapsed = keepalive_time_elapsed(tp); 2618 if (tp->keepalive_time > elapsed) 2619 elapsed = tp->keepalive_time - elapsed; 2620 else 2621 elapsed = 0; 2622 inet_csk_reset_keepalive_timer(sk, elapsed); 2623 } 2624 } 2625 break; 2626 case TCP_KEEPINTVL: 2627 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2628 err = -EINVAL; 2629 else 2630 tp->keepalive_intvl = val * HZ; 2631 break; 2632 case TCP_KEEPCNT: 2633 if (val < 1 || val > MAX_TCP_KEEPCNT) 2634 err = -EINVAL; 2635 else 2636 tp->keepalive_probes = val; 2637 break; 2638 case TCP_SYNCNT: 2639 if (val < 1 || val > MAX_TCP_SYNCNT) 2640 err = -EINVAL; 2641 else 2642 icsk->icsk_syn_retries = val; 2643 break; 2644 2645 case TCP_LINGER2: 2646 if (val < 0) 2647 tp->linger2 = -1; 2648 else if (val > sysctl_tcp_fin_timeout / HZ) 2649 tp->linger2 = 0; 2650 else 2651 tp->linger2 = val * HZ; 2652 break; 2653 2654 case TCP_DEFER_ACCEPT: 2655 /* Translate value in seconds to number of retransmits */ 2656 icsk->icsk_accept_queue.rskq_defer_accept = 2657 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2658 TCP_RTO_MAX / HZ); 2659 break; 2660 2661 case TCP_WINDOW_CLAMP: 2662 if (!val) { 2663 if (sk->sk_state != TCP_CLOSE) { 2664 err = -EINVAL; 2665 break; 2666 } 2667 tp->window_clamp = 0; 2668 } else 2669 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2670 SOCK_MIN_RCVBUF / 2 : val; 2671 break; 2672 2673 case TCP_QUICKACK: 2674 if (!val) { 2675 icsk->icsk_ack.pingpong = 1; 2676 } else { 2677 icsk->icsk_ack.pingpong = 0; 2678 if ((1 << sk->sk_state) & 2679 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2680 inet_csk_ack_scheduled(sk)) { 2681 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2682 tcp_cleanup_rbuf(sk, 1); 2683 if (!(val & 1)) 2684 icsk->icsk_ack.pingpong = 1; 2685 } 2686 } 2687 break; 2688 2689#ifdef CONFIG_TCP_MD5SIG 2690 case TCP_MD5SIG: 2691 /* Read the IP->Key mappings from userspace */ 2692 err = tp->af_specific->md5_parse(sk, optval, optlen); 2693 break; 2694#endif 2695 case TCP_USER_TIMEOUT: 2696 /* Cap the max timeout in ms TCP will retry/retrans 2697 * before giving up and aborting (ETIMEDOUT) a connection. 2698 */ 2699 if (val < 0) 2700 err = -EINVAL; 2701 else 2702 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2703 break; 2704 2705 case TCP_FASTOPEN: 2706 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE | 2707 TCPF_LISTEN))) 2708 err = fastopen_init_queue(sk, val); 2709 else 2710 err = -EINVAL; 2711 break; 2712 case TCP_TIMESTAMP: 2713 if (!tp->repair) 2714 err = -EPERM; 2715 else 2716 tp->tsoffset = val - tcp_time_stamp; 2717 break; 2718 case TCP_NOTSENT_LOWAT: 2719 tp->notsent_lowat = val; 2720 sk->sk_write_space(sk); 2721 break; 2722 default: 2723 err = -ENOPROTOOPT; 2724 break; 2725 } 2726 2727 release_sock(sk); 2728 return err; 2729} 2730 2731int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2732 unsigned int optlen) 2733{ 2734 const struct inet_connection_sock *icsk = inet_csk(sk); 2735 2736 if (level != SOL_TCP) 2737 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2738 optval, optlen); 2739 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2740} 2741EXPORT_SYMBOL(tcp_setsockopt); 2742 2743#ifdef CONFIG_COMPAT 2744int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2745 char __user *optval, unsigned int optlen) 2746{ 2747 if (level != SOL_TCP) 2748 return inet_csk_compat_setsockopt(sk, level, optname, 2749 optval, optlen); 2750 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2751} 2752EXPORT_SYMBOL(compat_tcp_setsockopt); 2753#endif 2754 2755/* Return information about state of tcp endpoint in API format. */ 2756void tcp_get_info(const struct sock *sk, struct tcp_info *info) 2757{ 2758 const struct tcp_sock *tp = tcp_sk(sk); 2759 const struct inet_connection_sock *icsk = inet_csk(sk); 2760 u32 now = tcp_time_stamp; 2761 2762 memset(info, 0, sizeof(*info)); 2763 2764 info->tcpi_state = sk->sk_state; 2765 info->tcpi_ca_state = icsk->icsk_ca_state; 2766 info->tcpi_retransmits = icsk->icsk_retransmits; 2767 info->tcpi_probes = icsk->icsk_probes_out; 2768 info->tcpi_backoff = icsk->icsk_backoff; 2769 2770 if (tp->rx_opt.tstamp_ok) 2771 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2772 if (tcp_is_sack(tp)) 2773 info->tcpi_options |= TCPI_OPT_SACK; 2774 if (tp->rx_opt.wscale_ok) { 2775 info->tcpi_options |= TCPI_OPT_WSCALE; 2776 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2777 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2778 } 2779 2780 if (tp->ecn_flags & TCP_ECN_OK) 2781 info->tcpi_options |= TCPI_OPT_ECN; 2782 if (tp->ecn_flags & TCP_ECN_SEEN) 2783 info->tcpi_options |= TCPI_OPT_ECN_SEEN; 2784 if (tp->syn_data_acked) 2785 info->tcpi_options |= TCPI_OPT_SYN_DATA; 2786 2787 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2788 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2789 info->tcpi_snd_mss = tp->mss_cache; 2790 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2791 2792 if (sk->sk_state == TCP_LISTEN) { 2793 info->tcpi_unacked = sk->sk_ack_backlog; 2794 info->tcpi_sacked = sk->sk_max_ack_backlog; 2795 } else { 2796 info->tcpi_unacked = tp->packets_out; 2797 info->tcpi_sacked = tp->sacked_out; 2798 } 2799 info->tcpi_lost = tp->lost_out; 2800 info->tcpi_retrans = tp->retrans_out; 2801 info->tcpi_fackets = tp->fackets_out; 2802 2803 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2804 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2805 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2806 2807 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2808 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2809 info->tcpi_rtt = tp->srtt_us >> 3; 2810 info->tcpi_rttvar = tp->mdev_us >> 2; 2811 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2812 info->tcpi_snd_cwnd = tp->snd_cwnd; 2813 info->tcpi_advmss = tp->advmss; 2814 info->tcpi_reordering = tp->reordering; 2815 2816 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2817 info->tcpi_rcv_space = tp->rcvq_space.space; 2818 2819 info->tcpi_total_retrans = tp->total_retrans; 2820 2821 info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ? 2822 sk->sk_pacing_rate : ~0ULL; 2823 info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ? 2824 sk->sk_max_pacing_rate : ~0ULL; 2825} 2826EXPORT_SYMBOL_GPL(tcp_get_info); 2827 2828static int do_tcp_getsockopt(struct sock *sk, int level, 2829 int optname, char __user *optval, int __user *optlen) 2830{ 2831 struct inet_connection_sock *icsk = inet_csk(sk); 2832 struct tcp_sock *tp = tcp_sk(sk); 2833 int val, len; 2834 2835 if (get_user(len, optlen)) 2836 return -EFAULT; 2837 2838 len = min_t(unsigned int, len, sizeof(int)); 2839 2840 if (len < 0) 2841 return -EINVAL; 2842 2843 switch (optname) { 2844 case TCP_MAXSEG: 2845 val = tp->mss_cache; 2846 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2847 val = tp->rx_opt.user_mss; 2848 if (tp->repair) 2849 val = tp->rx_opt.mss_clamp; 2850 break; 2851 case TCP_NODELAY: 2852 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2853 break; 2854 case TCP_CORK: 2855 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2856 break; 2857 case TCP_KEEPIDLE: 2858 val = keepalive_time_when(tp) / HZ; 2859 break; 2860 case TCP_KEEPINTVL: 2861 val = keepalive_intvl_when(tp) / HZ; 2862 break; 2863 case TCP_KEEPCNT: 2864 val = keepalive_probes(tp); 2865 break; 2866 case TCP_SYNCNT: 2867 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2868 break; 2869 case TCP_LINGER2: 2870 val = tp->linger2; 2871 if (val >= 0) 2872 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2873 break; 2874 case TCP_DEFER_ACCEPT: 2875 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2876 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2877 break; 2878 case TCP_WINDOW_CLAMP: 2879 val = tp->window_clamp; 2880 break; 2881 case TCP_INFO: { 2882 struct tcp_info info; 2883 2884 if (get_user(len, optlen)) 2885 return -EFAULT; 2886 2887 tcp_get_info(sk, &info); 2888 2889 len = min_t(unsigned int, len, sizeof(info)); 2890 if (put_user(len, optlen)) 2891 return -EFAULT; 2892 if (copy_to_user(optval, &info, len)) 2893 return -EFAULT; 2894 return 0; 2895 } 2896 case TCP_QUICKACK: 2897 val = !icsk->icsk_ack.pingpong; 2898 break; 2899 2900 case TCP_CONGESTION: 2901 if (get_user(len, optlen)) 2902 return -EFAULT; 2903 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2904 if (put_user(len, optlen)) 2905 return -EFAULT; 2906 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2907 return -EFAULT; 2908 return 0; 2909 2910 case TCP_THIN_LINEAR_TIMEOUTS: 2911 val = tp->thin_lto; 2912 break; 2913 case TCP_THIN_DUPACK: 2914 val = tp->thin_dupack; 2915 break; 2916 2917 case TCP_REPAIR: 2918 val = tp->repair; 2919 break; 2920 2921 case TCP_REPAIR_QUEUE: 2922 if (tp->repair) 2923 val = tp->repair_queue; 2924 else 2925 return -EINVAL; 2926 break; 2927 2928 case TCP_QUEUE_SEQ: 2929 if (tp->repair_queue == TCP_SEND_QUEUE) 2930 val = tp->write_seq; 2931 else if (tp->repair_queue == TCP_RECV_QUEUE) 2932 val = tp->rcv_nxt; 2933 else 2934 return -EINVAL; 2935 break; 2936 2937 case TCP_USER_TIMEOUT: 2938 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2939 break; 2940 2941 case TCP_FASTOPEN: 2942 if (icsk->icsk_accept_queue.fastopenq != NULL) 2943 val = icsk->icsk_accept_queue.fastopenq->max_qlen; 2944 else 2945 val = 0; 2946 break; 2947 2948 case TCP_TIMESTAMP: 2949 val = tcp_time_stamp + tp->tsoffset; 2950 break; 2951 case TCP_NOTSENT_LOWAT: 2952 val = tp->notsent_lowat; 2953 break; 2954 default: 2955 return -ENOPROTOOPT; 2956 } 2957 2958 if (put_user(len, optlen)) 2959 return -EFAULT; 2960 if (copy_to_user(optval, &val, len)) 2961 return -EFAULT; 2962 return 0; 2963} 2964 2965int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2966 int __user *optlen) 2967{ 2968 struct inet_connection_sock *icsk = inet_csk(sk); 2969 2970 if (level != SOL_TCP) 2971 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2972 optval, optlen); 2973 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2974} 2975EXPORT_SYMBOL(tcp_getsockopt); 2976 2977#ifdef CONFIG_COMPAT 2978int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2979 char __user *optval, int __user *optlen) 2980{ 2981 if (level != SOL_TCP) 2982 return inet_csk_compat_getsockopt(sk, level, optname, 2983 optval, optlen); 2984 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2985} 2986EXPORT_SYMBOL(compat_tcp_getsockopt); 2987#endif 2988 2989#ifdef CONFIG_TCP_MD5SIG 2990static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool __read_mostly; 2991static DEFINE_MUTEX(tcp_md5sig_mutex); 2992 2993static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool) 2994{ 2995 int cpu; 2996 2997 for_each_possible_cpu(cpu) { 2998 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu); 2999 3000 if (p->md5_desc.tfm) 3001 crypto_free_hash(p->md5_desc.tfm); 3002 } 3003 free_percpu(pool); 3004} 3005 3006static void __tcp_alloc_md5sig_pool(void) 3007{ 3008 int cpu; 3009 struct tcp_md5sig_pool __percpu *pool; 3010 3011 pool = alloc_percpu(struct tcp_md5sig_pool); 3012 if (!pool) 3013 return; 3014 3015 for_each_possible_cpu(cpu) { 3016 struct crypto_hash *hash; 3017 3018 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 3019 if (IS_ERR_OR_NULL(hash)) 3020 goto out_free; 3021 3022 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash; 3023 } 3024 /* before setting tcp_md5sig_pool, we must commit all writes 3025 * to memory. See ACCESS_ONCE() in tcp_get_md5sig_pool() 3026 */ 3027 smp_wmb(); 3028 tcp_md5sig_pool = pool; 3029 return; 3030out_free: 3031 __tcp_free_md5sig_pool(pool); 3032} 3033 3034bool tcp_alloc_md5sig_pool(void) 3035{ 3036 if (unlikely(!tcp_md5sig_pool)) { 3037 mutex_lock(&tcp_md5sig_mutex); 3038 3039 if (!tcp_md5sig_pool) 3040 __tcp_alloc_md5sig_pool(); 3041 3042 mutex_unlock(&tcp_md5sig_mutex); 3043 } 3044 return tcp_md5sig_pool != NULL; 3045} 3046EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 3047 3048 3049/** 3050 * tcp_get_md5sig_pool - get md5sig_pool for this user 3051 * 3052 * We use percpu structure, so if we succeed, we exit with preemption 3053 * and BH disabled, to make sure another thread or softirq handling 3054 * wont try to get same context. 3055 */ 3056struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 3057{ 3058 struct tcp_md5sig_pool __percpu *p; 3059 3060 local_bh_disable(); 3061 p = ACCESS_ONCE(tcp_md5sig_pool); 3062 if (p) 3063 return __this_cpu_ptr(p); 3064 3065 local_bh_enable(); 3066 return NULL; 3067} 3068EXPORT_SYMBOL(tcp_get_md5sig_pool); 3069 3070int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 3071 const struct tcphdr *th) 3072{ 3073 struct scatterlist sg; 3074 struct tcphdr hdr; 3075 int err; 3076 3077 /* We are not allowed to change tcphdr, make a local copy */ 3078 memcpy(&hdr, th, sizeof(hdr)); 3079 hdr.check = 0; 3080 3081 /* options aren't included in the hash */ 3082 sg_init_one(&sg, &hdr, sizeof(hdr)); 3083 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr)); 3084 return err; 3085} 3086EXPORT_SYMBOL(tcp_md5_hash_header); 3087 3088int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 3089 const struct sk_buff *skb, unsigned int header_len) 3090{ 3091 struct scatterlist sg; 3092 const struct tcphdr *tp = tcp_hdr(skb); 3093 struct hash_desc *desc = &hp->md5_desc; 3094 unsigned int i; 3095 const unsigned int head_data_len = skb_headlen(skb) > header_len ? 3096 skb_headlen(skb) - header_len : 0; 3097 const struct skb_shared_info *shi = skb_shinfo(skb); 3098 struct sk_buff *frag_iter; 3099 3100 sg_init_table(&sg, 1); 3101 3102 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 3103 if (crypto_hash_update(desc, &sg, head_data_len)) 3104 return 1; 3105 3106 for (i = 0; i < shi->nr_frags; ++i) { 3107 const struct skb_frag_struct *f = &shi->frags[i]; 3108 unsigned int offset = f->page_offset; 3109 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); 3110 3111 sg_set_page(&sg, page, skb_frag_size(f), 3112 offset_in_page(offset)); 3113 if (crypto_hash_update(desc, &sg, skb_frag_size(f))) 3114 return 1; 3115 } 3116 3117 skb_walk_frags(skb, frag_iter) 3118 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 3119 return 1; 3120 3121 return 0; 3122} 3123EXPORT_SYMBOL(tcp_md5_hash_skb_data); 3124 3125int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) 3126{ 3127 struct scatterlist sg; 3128 3129 sg_init_one(&sg, key->key, key->keylen); 3130 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 3131} 3132EXPORT_SYMBOL(tcp_md5_hash_key); 3133 3134#endif 3135 3136void tcp_done(struct sock *sk) 3137{ 3138 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 3139 3140 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 3141 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 3142 3143 tcp_set_state(sk, TCP_CLOSE); 3144 tcp_clear_xmit_timers(sk); 3145 if (req != NULL) 3146 reqsk_fastopen_remove(sk, req, false); 3147 3148 sk->sk_shutdown = SHUTDOWN_MASK; 3149 3150 if (!sock_flag(sk, SOCK_DEAD)) 3151 sk->sk_state_change(sk); 3152 else 3153 inet_csk_destroy_sock(sk); 3154} 3155EXPORT_SYMBOL_GPL(tcp_done); 3156 3157extern struct tcp_congestion_ops tcp_reno; 3158 3159static __initdata unsigned long thash_entries; 3160static int __init set_thash_entries(char *str) 3161{ 3162 ssize_t ret; 3163 3164 if (!str) 3165 return 0; 3166 3167 ret = kstrtoul(str, 0, &thash_entries); 3168 if (ret) 3169 return 0; 3170 3171 return 1; 3172} 3173__setup("thash_entries=", set_thash_entries); 3174 3175static void tcp_init_mem(void) 3176{ 3177 unsigned long limit = nr_free_buffer_pages() / 8; 3178 limit = max(limit, 128UL); 3179 sysctl_tcp_mem[0] = limit / 4 * 3; 3180 sysctl_tcp_mem[1] = limit; 3181 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 3182} 3183 3184void __init tcp_init(void) 3185{ 3186 struct sk_buff *skb = NULL; 3187 unsigned long limit; 3188 int max_rshare, max_wshare, cnt; 3189 unsigned int i; 3190 3191 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 3192 3193 percpu_counter_init(&tcp_sockets_allocated, 0); 3194 percpu_counter_init(&tcp_orphan_count, 0); 3195 tcp_hashinfo.bind_bucket_cachep = 3196 kmem_cache_create("tcp_bind_bucket", 3197 sizeof(struct inet_bind_bucket), 0, 3198 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3199 3200 /* Size and allocate the main established and bind bucket 3201 * hash tables. 3202 * 3203 * The methodology is similar to that of the buffer cache. 3204 */ 3205 tcp_hashinfo.ehash = 3206 alloc_large_system_hash("TCP established", 3207 sizeof(struct inet_ehash_bucket), 3208 thash_entries, 3209 17, /* one slot per 128 KB of memory */ 3210 0, 3211 NULL, 3212 &tcp_hashinfo.ehash_mask, 3213 0, 3214 thash_entries ? 0 : 512 * 1024); 3215 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) 3216 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3217 3218 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3219 panic("TCP: failed to alloc ehash_locks"); 3220 tcp_hashinfo.bhash = 3221 alloc_large_system_hash("TCP bind", 3222 sizeof(struct inet_bind_hashbucket), 3223 tcp_hashinfo.ehash_mask + 1, 3224 17, /* one slot per 128 KB of memory */ 3225 0, 3226 &tcp_hashinfo.bhash_size, 3227 NULL, 3228 0, 3229 64 * 1024); 3230 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size; 3231 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3232 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3233 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3234 } 3235 3236 3237 cnt = tcp_hashinfo.ehash_mask + 1; 3238 3239 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3240 sysctl_tcp_max_orphans = cnt / 2; 3241 sysctl_max_syn_backlog = max(128, cnt / 256); 3242 3243 tcp_init_mem(); 3244 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3245 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7); 3246 max_wshare = min(4UL*1024*1024, limit); 3247 max_rshare = min(6UL*1024*1024, limit); 3248 3249 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3250 sysctl_tcp_wmem[1] = 16*1024; 3251 sysctl_tcp_wmem[2] = max(64*1024, max_wshare); 3252 3253 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3254 sysctl_tcp_rmem[1] = 87380; 3255 sysctl_tcp_rmem[2] = max(87380, max_rshare); 3256 3257 pr_info("Hash tables configured (established %u bind %u)\n", 3258 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3259 3260 tcp_metrics_init(); 3261 3262 tcp_register_congestion_control(&tcp_reno); 3263 3264 tcp_tasklet_init(); 3265} 3266