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/sock.h> 278 279 #include <asm/uaccess.h> 280 #include <asm/ioctls.h> 281 #include <net/busy_poll.h> 282 283 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 284 285 int sysctl_tcp_min_tso_segs __read_mostly = 2; 286 287 int sysctl_tcp_autocorking __read_mostly = 1; 288 289 struct percpu_counter tcp_orphan_count; 290 EXPORT_SYMBOL_GPL(tcp_orphan_count); 291 292 long sysctl_tcp_mem[3] __read_mostly; 293 int sysctl_tcp_wmem[3] __read_mostly; 294 int sysctl_tcp_rmem[3] __read_mostly; 295 296 EXPORT_SYMBOL(sysctl_tcp_mem); 297 EXPORT_SYMBOL(sysctl_tcp_rmem); 298 EXPORT_SYMBOL(sysctl_tcp_wmem); 299 300 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ 301 EXPORT_SYMBOL(tcp_memory_allocated); 302 303 /* 304 * Current number of TCP sockets. 305 */ 306 struct percpu_counter tcp_sockets_allocated; 307 EXPORT_SYMBOL(tcp_sockets_allocated); 308 309 /* 310 * TCP splice context 311 */ 312 struct tcp_splice_state { 313 struct pipe_inode_info *pipe; 314 size_t len; 315 unsigned int flags; 316 }; 317 318 /* 319 * Pressure flag: try to collapse. 320 * Technical note: it is used by multiple contexts non atomically. 321 * All the __sk_mem_schedule() is of this nature: accounting 322 * is strict, actions are advisory and have some latency. 323 */ 324 int tcp_memory_pressure __read_mostly; 325 EXPORT_SYMBOL(tcp_memory_pressure); 326 327 void tcp_enter_memory_pressure(struct sock *sk) 328 { 329 if (!tcp_memory_pressure) { 330 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 331 tcp_memory_pressure = 1; 332 } 333 } 334 EXPORT_SYMBOL(tcp_enter_memory_pressure); 335 336 /* Convert seconds to retransmits based on initial and max timeout */ 337 static u8 secs_to_retrans(int seconds, int timeout, int rto_max) 338 { 339 u8 res = 0; 340 341 if (seconds > 0) { 342 int period = timeout; 343 344 res = 1; 345 while (seconds > period && res < 255) { 346 res++; 347 timeout <<= 1; 348 if (timeout > rto_max) 349 timeout = rto_max; 350 period += timeout; 351 } 352 } 353 return res; 354 } 355 356 /* Convert retransmits to seconds based on initial and max timeout */ 357 static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 358 { 359 int period = 0; 360 361 if (retrans > 0) { 362 period = timeout; 363 while (--retrans) { 364 timeout <<= 1; 365 if (timeout > rto_max) 366 timeout = rto_max; 367 period += timeout; 368 } 369 } 370 return period; 371 } 372 373 /* Address-family independent initialization for a tcp_sock. 374 * 375 * NOTE: A lot of things set to zero explicitly by call to 376 * sk_alloc() so need not be done here. 377 */ 378 void tcp_init_sock(struct sock *sk) 379 { 380 struct inet_connection_sock *icsk = inet_csk(sk); 381 struct tcp_sock *tp = tcp_sk(sk); 382 383 __skb_queue_head_init(&tp->out_of_order_queue); 384 tcp_init_xmit_timers(sk); 385 tcp_prequeue_init(tp); 386 INIT_LIST_HEAD(&tp->tsq_node); 387 388 icsk->icsk_rto = TCP_TIMEOUT_INIT; 389 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); 390 391 /* So many TCP implementations out there (incorrectly) count the 392 * initial SYN frame in their delayed-ACK and congestion control 393 * algorithms that we must have the following bandaid to talk 394 * efficiently to them. -DaveM 395 */ 396 tp->snd_cwnd = TCP_INIT_CWND; 397 398 /* See draft-stevens-tcpca-spec-01 for discussion of the 399 * initialization of these values. 400 */ 401 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 402 tp->snd_cwnd_clamp = ~0; 403 tp->mss_cache = TCP_MSS_DEFAULT; 404 405 tp->reordering = sysctl_tcp_reordering; 406 tcp_enable_early_retrans(tp); 407 tcp_assign_congestion_control(sk); 408 409 tp->tsoffset = 0; 410 411 sk->sk_state = TCP_CLOSE; 412 413 sk->sk_write_space = sk_stream_write_space; 414 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 415 416 icsk->icsk_sync_mss = tcp_sync_mss; 417 418 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 419 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 420 421 local_bh_disable(); 422 sock_update_memcg(sk); 423 sk_sockets_allocated_inc(sk); 424 local_bh_enable(); 425 } 426 EXPORT_SYMBOL(tcp_init_sock); 427 428 static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb) 429 { 430 if (sk->sk_tsflags) { 431 struct skb_shared_info *shinfo = skb_shinfo(skb); 432 433 sock_tx_timestamp(sk, &shinfo->tx_flags); 434 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP) 435 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; 436 } 437 } 438 439 /* 440 * Wait for a TCP event. 441 * 442 * Note that we don't need to lock the socket, as the upper poll layers 443 * take care of normal races (between the test and the event) and we don't 444 * go look at any of the socket buffers directly. 445 */ 446 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 447 { 448 unsigned int mask; 449 struct sock *sk = sock->sk; 450 const struct tcp_sock *tp = tcp_sk(sk); 451 452 sock_rps_record_flow(sk); 453 454 sock_poll_wait(file, sk_sleep(sk), wait); 455 if (sk->sk_state == TCP_LISTEN) 456 return inet_csk_listen_poll(sk); 457 458 /* Socket is not locked. We are protected from async events 459 * by poll logic and correct handling of state changes 460 * made by other threads is impossible in any case. 461 */ 462 463 mask = 0; 464 465 /* 466 * POLLHUP is certainly not done right. But poll() doesn't 467 * have a notion of HUP in just one direction, and for a 468 * socket the read side is more interesting. 469 * 470 * Some poll() documentation says that POLLHUP is incompatible 471 * with the POLLOUT/POLLWR flags, so somebody should check this 472 * all. But careful, it tends to be safer to return too many 473 * bits than too few, and you can easily break real applications 474 * if you don't tell them that something has hung up! 475 * 476 * Check-me. 477 * 478 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 479 * our fs/select.c). It means that after we received EOF, 480 * poll always returns immediately, making impossible poll() on write() 481 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 482 * if and only if shutdown has been made in both directions. 483 * Actually, it is interesting to look how Solaris and DUX 484 * solve this dilemma. I would prefer, if POLLHUP were maskable, 485 * then we could set it on SND_SHUTDOWN. BTW examples given 486 * in Stevens' books assume exactly this behaviour, it explains 487 * why POLLHUP is incompatible with POLLOUT. --ANK 488 * 489 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 490 * blocking on fresh not-connected or disconnected socket. --ANK 491 */ 492 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 493 mask |= POLLHUP; 494 if (sk->sk_shutdown & RCV_SHUTDOWN) 495 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 496 497 /* Connected or passive Fast Open socket? */ 498 if (sk->sk_state != TCP_SYN_SENT && 499 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk)) { 500 int target = sock_rcvlowat(sk, 0, INT_MAX); 501 502 if (tp->urg_seq == tp->copied_seq && 503 !sock_flag(sk, SOCK_URGINLINE) && 504 tp->urg_data) 505 target++; 506 507 /* Potential race condition. If read of tp below will 508 * escape above sk->sk_state, we can be illegally awaken 509 * in SYN_* states. */ 510 if (tp->rcv_nxt - tp->copied_seq >= target) 511 mask |= POLLIN | POLLRDNORM; 512 513 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 514 if (sk_stream_is_writeable(sk)) { 515 mask |= POLLOUT | POLLWRNORM; 516 } else { /* send SIGIO later */ 517 set_bit(SOCK_ASYNC_NOSPACE, 518 &sk->sk_socket->flags); 519 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 520 521 /* Race breaker. If space is freed after 522 * wspace test but before the flags are set, 523 * IO signal will be lost. Memory barrier 524 * pairs with the input side. 525 */ 526 smp_mb__after_atomic(); 527 if (sk_stream_is_writeable(sk)) 528 mask |= POLLOUT | POLLWRNORM; 529 } 530 } else 531 mask |= POLLOUT | POLLWRNORM; 532 533 if (tp->urg_data & TCP_URG_VALID) 534 mask |= POLLPRI; 535 } 536 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 537 smp_rmb(); 538 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 539 mask |= POLLERR; 540 541 return mask; 542 } 543 EXPORT_SYMBOL(tcp_poll); 544 545 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 546 { 547 struct tcp_sock *tp = tcp_sk(sk); 548 int answ; 549 bool slow; 550 551 switch (cmd) { 552 case SIOCINQ: 553 if (sk->sk_state == TCP_LISTEN) 554 return -EINVAL; 555 556 slow = lock_sock_fast(sk); 557 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 558 answ = 0; 559 else if (sock_flag(sk, SOCK_URGINLINE) || 560 !tp->urg_data || 561 before(tp->urg_seq, tp->copied_seq) || 562 !before(tp->urg_seq, tp->rcv_nxt)) { 563 564 answ = tp->rcv_nxt - tp->copied_seq; 565 566 /* Subtract 1, if FIN was received */ 567 if (answ && sock_flag(sk, SOCK_DONE)) 568 answ--; 569 } else 570 answ = tp->urg_seq - tp->copied_seq; 571 unlock_sock_fast(sk, slow); 572 break; 573 case SIOCATMARK: 574 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 575 break; 576 case SIOCOUTQ: 577 if (sk->sk_state == TCP_LISTEN) 578 return -EINVAL; 579 580 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 581 answ = 0; 582 else 583 answ = tp->write_seq - tp->snd_una; 584 break; 585 case SIOCOUTQNSD: 586 if (sk->sk_state == TCP_LISTEN) 587 return -EINVAL; 588 589 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 590 answ = 0; 591 else 592 answ = tp->write_seq - tp->snd_nxt; 593 break; 594 default: 595 return -ENOIOCTLCMD; 596 } 597 598 return put_user(answ, (int __user *)arg); 599 } 600 EXPORT_SYMBOL(tcp_ioctl); 601 602 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 603 { 604 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH; 605 tp->pushed_seq = tp->write_seq; 606 } 607 608 static inline bool forced_push(const struct tcp_sock *tp) 609 { 610 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 611 } 612 613 static void skb_entail(struct sock *sk, struct sk_buff *skb) 614 { 615 struct tcp_sock *tp = tcp_sk(sk); 616 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 617 618 skb->csum = 0; 619 tcb->seq = tcb->end_seq = tp->write_seq; 620 tcb->tcp_flags = TCPHDR_ACK; 621 tcb->sacked = 0; 622 __skb_header_release(skb); 623 tcp_add_write_queue_tail(sk, skb); 624 sk->sk_wmem_queued += skb->truesize; 625 sk_mem_charge(sk, skb->truesize); 626 if (tp->nonagle & TCP_NAGLE_PUSH) 627 tp->nonagle &= ~TCP_NAGLE_PUSH; 628 } 629 630 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 631 { 632 if (flags & MSG_OOB) 633 tp->snd_up = tp->write_seq; 634 } 635 636 /* If a not yet filled skb is pushed, do not send it if 637 * we have data packets in Qdisc or NIC queues : 638 * Because TX completion will happen shortly, it gives a chance 639 * to coalesce future sendmsg() payload into this skb, without 640 * need for a timer, and with no latency trade off. 641 * As packets containing data payload have a bigger truesize 642 * than pure acks (dataless) packets, the last checks prevent 643 * autocorking if we only have an ACK in Qdisc/NIC queues, 644 * or if TX completion was delayed after we processed ACK packet. 645 */ 646 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb, 647 int size_goal) 648 { 649 return skb->len < size_goal && 650 sysctl_tcp_autocorking && 651 skb != tcp_write_queue_head(sk) && 652 atomic_read(&sk->sk_wmem_alloc) > skb->truesize; 653 } 654 655 static void tcp_push(struct sock *sk, int flags, int mss_now, 656 int nonagle, int size_goal) 657 { 658 struct tcp_sock *tp = tcp_sk(sk); 659 struct sk_buff *skb; 660 661 if (!tcp_send_head(sk)) 662 return; 663 664 skb = tcp_write_queue_tail(sk); 665 if (!(flags & MSG_MORE) || forced_push(tp)) 666 tcp_mark_push(tp, skb); 667 668 tcp_mark_urg(tp, flags); 669 670 if (tcp_should_autocork(sk, skb, size_goal)) { 671 672 /* avoid atomic op if TSQ_THROTTLED bit is already set */ 673 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) { 674 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); 675 set_bit(TSQ_THROTTLED, &tp->tsq_flags); 676 } 677 /* It is possible TX completion already happened 678 * before we set TSQ_THROTTLED. 679 */ 680 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize) 681 return; 682 } 683 684 if (flags & MSG_MORE) 685 nonagle = TCP_NAGLE_CORK; 686 687 __tcp_push_pending_frames(sk, mss_now, nonagle); 688 } 689 690 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 691 unsigned int offset, size_t len) 692 { 693 struct tcp_splice_state *tss = rd_desc->arg.data; 694 int ret; 695 696 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 697 tss->flags); 698 if (ret > 0) 699 rd_desc->count -= ret; 700 return ret; 701 } 702 703 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 704 { 705 /* Store TCP splice context information in read_descriptor_t. */ 706 read_descriptor_t rd_desc = { 707 .arg.data = tss, 708 .count = tss->len, 709 }; 710 711 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 712 } 713 714 /** 715 * tcp_splice_read - splice data from TCP socket to a pipe 716 * @sock: socket to splice from 717 * @ppos: position (not valid) 718 * @pipe: pipe to splice to 719 * @len: number of bytes to splice 720 * @flags: splice modifier flags 721 * 722 * Description: 723 * Will read pages from given socket and fill them into a pipe. 724 * 725 **/ 726 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 727 struct pipe_inode_info *pipe, size_t len, 728 unsigned int flags) 729 { 730 struct sock *sk = sock->sk; 731 struct tcp_splice_state tss = { 732 .pipe = pipe, 733 .len = len, 734 .flags = flags, 735 }; 736 long timeo; 737 ssize_t spliced; 738 int ret; 739 740 sock_rps_record_flow(sk); 741 /* 742 * We can't seek on a socket input 743 */ 744 if (unlikely(*ppos)) 745 return -ESPIPE; 746 747 ret = spliced = 0; 748 749 lock_sock(sk); 750 751 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 752 while (tss.len) { 753 ret = __tcp_splice_read(sk, &tss); 754 if (ret < 0) 755 break; 756 else if (!ret) { 757 if (spliced) 758 break; 759 if (sock_flag(sk, SOCK_DONE)) 760 break; 761 if (sk->sk_err) { 762 ret = sock_error(sk); 763 break; 764 } 765 if (sk->sk_shutdown & RCV_SHUTDOWN) 766 break; 767 if (sk->sk_state == TCP_CLOSE) { 768 /* 769 * This occurs when user tries to read 770 * from never connected socket. 771 */ 772 if (!sock_flag(sk, SOCK_DONE)) 773 ret = -ENOTCONN; 774 break; 775 } 776 if (!timeo) { 777 ret = -EAGAIN; 778 break; 779 } 780 sk_wait_data(sk, &timeo); 781 if (signal_pending(current)) { 782 ret = sock_intr_errno(timeo); 783 break; 784 } 785 continue; 786 } 787 tss.len -= ret; 788 spliced += ret; 789 790 if (!timeo) 791 break; 792 release_sock(sk); 793 lock_sock(sk); 794 795 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 796 (sk->sk_shutdown & RCV_SHUTDOWN) || 797 signal_pending(current)) 798 break; 799 } 800 801 release_sock(sk); 802 803 if (spliced) 804 return spliced; 805 806 return ret; 807 } 808 EXPORT_SYMBOL(tcp_splice_read); 809 810 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 811 { 812 struct sk_buff *skb; 813 814 /* The TCP header must be at least 32-bit aligned. */ 815 size = ALIGN(size, 4); 816 817 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 818 if (skb) { 819 if (sk_wmem_schedule(sk, skb->truesize)) { 820 skb_reserve(skb, sk->sk_prot->max_header); 821 /* 822 * Make sure that we have exactly size bytes 823 * available to the caller, no more, no less. 824 */ 825 skb->reserved_tailroom = skb->end - skb->tail - size; 826 return skb; 827 } 828 __kfree_skb(skb); 829 } else { 830 sk->sk_prot->enter_memory_pressure(sk); 831 sk_stream_moderate_sndbuf(sk); 832 } 833 return NULL; 834 } 835 836 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 837 int large_allowed) 838 { 839 struct tcp_sock *tp = tcp_sk(sk); 840 u32 new_size_goal, size_goal; 841 842 if (!large_allowed || !sk_can_gso(sk)) 843 return mss_now; 844 845 /* Note : tcp_tso_autosize() will eventually split this later */ 846 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER; 847 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal); 848 849 /* We try hard to avoid divides here */ 850 size_goal = tp->gso_segs * mss_now; 851 if (unlikely(new_size_goal < size_goal || 852 new_size_goal >= size_goal + mss_now)) { 853 tp->gso_segs = min_t(u16, new_size_goal / mss_now, 854 sk->sk_gso_max_segs); 855 size_goal = tp->gso_segs * mss_now; 856 } 857 858 return max(size_goal, mss_now); 859 } 860 861 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 862 { 863 int mss_now; 864 865 mss_now = tcp_current_mss(sk); 866 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 867 868 return mss_now; 869 } 870 871 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 872 size_t size, int flags) 873 { 874 struct tcp_sock *tp = tcp_sk(sk); 875 int mss_now, size_goal; 876 int err; 877 ssize_t copied; 878 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 879 880 /* Wait for a connection to finish. One exception is TCP Fast Open 881 * (passive side) where data is allowed to be sent before a connection 882 * is fully established. 883 */ 884 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 885 !tcp_passive_fastopen(sk)) { 886 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 887 goto out_err; 888 } 889 890 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 891 892 mss_now = tcp_send_mss(sk, &size_goal, flags); 893 copied = 0; 894 895 err = -EPIPE; 896 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 897 goto out_err; 898 899 while (size > 0) { 900 struct sk_buff *skb = tcp_write_queue_tail(sk); 901 int copy, i; 902 bool can_coalesce; 903 904 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 905 new_segment: 906 if (!sk_stream_memory_free(sk)) 907 goto wait_for_sndbuf; 908 909 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 910 if (!skb) 911 goto wait_for_memory; 912 913 skb_entail(sk, skb); 914 copy = size_goal; 915 } 916 917 if (copy > size) 918 copy = size; 919 920 i = skb_shinfo(skb)->nr_frags; 921 can_coalesce = skb_can_coalesce(skb, i, page, offset); 922 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 923 tcp_mark_push(tp, skb); 924 goto new_segment; 925 } 926 if (!sk_wmem_schedule(sk, copy)) 927 goto wait_for_memory; 928 929 if (can_coalesce) { 930 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 931 } else { 932 get_page(page); 933 skb_fill_page_desc(skb, i, page, offset, copy); 934 } 935 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 936 937 skb->len += copy; 938 skb->data_len += copy; 939 skb->truesize += copy; 940 sk->sk_wmem_queued += copy; 941 sk_mem_charge(sk, copy); 942 skb->ip_summed = CHECKSUM_PARTIAL; 943 tp->write_seq += copy; 944 TCP_SKB_CB(skb)->end_seq += copy; 945 tcp_skb_pcount_set(skb, 0); 946 947 if (!copied) 948 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 949 950 copied += copy; 951 offset += copy; 952 if (!(size -= copy)) { 953 tcp_tx_timestamp(sk, skb); 954 goto out; 955 } 956 957 if (skb->len < size_goal || (flags & MSG_OOB)) 958 continue; 959 960 if (forced_push(tp)) { 961 tcp_mark_push(tp, skb); 962 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 963 } else if (skb == tcp_send_head(sk)) 964 tcp_push_one(sk, mss_now); 965 continue; 966 967 wait_for_sndbuf: 968 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 969 wait_for_memory: 970 tcp_push(sk, flags & ~MSG_MORE, mss_now, 971 TCP_NAGLE_PUSH, size_goal); 972 973 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 974 goto do_error; 975 976 mss_now = tcp_send_mss(sk, &size_goal, flags); 977 } 978 979 out: 980 if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) 981 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 982 return copied; 983 984 do_error: 985 if (copied) 986 goto out; 987 out_err: 988 return sk_stream_error(sk, flags, err); 989 } 990 991 int tcp_sendpage(struct sock *sk, struct page *page, int offset, 992 size_t size, int flags) 993 { 994 ssize_t res; 995 996 if (!(sk->sk_route_caps & NETIF_F_SG) || 997 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 998 return sock_no_sendpage(sk->sk_socket, page, offset, size, 999 flags); 1000 1001 lock_sock(sk); 1002 res = do_tcp_sendpages(sk, page, offset, size, flags); 1003 release_sock(sk); 1004 return res; 1005 } 1006 EXPORT_SYMBOL(tcp_sendpage); 1007 1008 static inline int select_size(const struct sock *sk, bool sg) 1009 { 1010 const struct tcp_sock *tp = tcp_sk(sk); 1011 int tmp = tp->mss_cache; 1012 1013 if (sg) { 1014 if (sk_can_gso(sk)) { 1015 /* Small frames wont use a full page: 1016 * Payload will immediately follow tcp header. 1017 */ 1018 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER); 1019 } else { 1020 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 1021 1022 if (tmp >= pgbreak && 1023 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 1024 tmp = pgbreak; 1025 } 1026 } 1027 1028 return tmp; 1029 } 1030 1031 void tcp_free_fastopen_req(struct tcp_sock *tp) 1032 { 1033 if (tp->fastopen_req) { 1034 kfree(tp->fastopen_req); 1035 tp->fastopen_req = NULL; 1036 } 1037 } 1038 1039 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, 1040 int *copied, size_t size) 1041 { 1042 struct tcp_sock *tp = tcp_sk(sk); 1043 int err, flags; 1044 1045 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE)) 1046 return -EOPNOTSUPP; 1047 if (tp->fastopen_req) 1048 return -EALREADY; /* Another Fast Open is in progress */ 1049 1050 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request), 1051 sk->sk_allocation); 1052 if (unlikely(!tp->fastopen_req)) 1053 return -ENOBUFS; 1054 tp->fastopen_req->data = msg; 1055 tp->fastopen_req->size = size; 1056 1057 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; 1058 err = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1059 msg->msg_namelen, flags); 1060 *copied = tp->fastopen_req->copied; 1061 tcp_free_fastopen_req(tp); 1062 return err; 1063 } 1064 1065 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 1066 { 1067 struct tcp_sock *tp = tcp_sk(sk); 1068 struct sk_buff *skb; 1069 int flags, err, copied = 0; 1070 int mss_now = 0, size_goal, copied_syn = 0; 1071 bool sg; 1072 long timeo; 1073 1074 lock_sock(sk); 1075 1076 flags = msg->msg_flags; 1077 if (flags & MSG_FASTOPEN) { 1078 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size); 1079 if (err == -EINPROGRESS && copied_syn > 0) 1080 goto out; 1081 else if (err) 1082 goto out_err; 1083 } 1084 1085 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 1086 1087 /* Wait for a connection to finish. One exception is TCP Fast Open 1088 * (passive side) where data is allowed to be sent before a connection 1089 * is fully established. 1090 */ 1091 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 1092 !tcp_passive_fastopen(sk)) { 1093 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 1094 goto do_error; 1095 } 1096 1097 if (unlikely(tp->repair)) { 1098 if (tp->repair_queue == TCP_RECV_QUEUE) { 1099 copied = tcp_send_rcvq(sk, msg, size); 1100 goto out_nopush; 1101 } 1102 1103 err = -EINVAL; 1104 if (tp->repair_queue == TCP_NO_QUEUE) 1105 goto out_err; 1106 1107 /* 'common' sending to sendq */ 1108 } 1109 1110 /* This should be in poll */ 1111 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 1112 1113 mss_now = tcp_send_mss(sk, &size_goal, flags); 1114 1115 /* Ok commence sending. */ 1116 copied = 0; 1117 1118 err = -EPIPE; 1119 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 1120 goto out_err; 1121 1122 sg = !!(sk->sk_route_caps & NETIF_F_SG); 1123 1124 while (msg_data_left(msg)) { 1125 int copy = 0; 1126 int max = size_goal; 1127 1128 skb = tcp_write_queue_tail(sk); 1129 if (tcp_send_head(sk)) { 1130 if (skb->ip_summed == CHECKSUM_NONE) 1131 max = mss_now; 1132 copy = max - skb->len; 1133 } 1134 1135 if (copy <= 0) { 1136 new_segment: 1137 /* Allocate new segment. If the interface is SG, 1138 * allocate skb fitting to single page. 1139 */ 1140 if (!sk_stream_memory_free(sk)) 1141 goto wait_for_sndbuf; 1142 1143 skb = sk_stream_alloc_skb(sk, 1144 select_size(sk, sg), 1145 sk->sk_allocation); 1146 if (!skb) 1147 goto wait_for_memory; 1148 1149 /* 1150 * Check whether we can use HW checksum. 1151 */ 1152 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 1153 skb->ip_summed = CHECKSUM_PARTIAL; 1154 1155 skb_entail(sk, skb); 1156 copy = size_goal; 1157 max = size_goal; 1158 1159 /* All packets are restored as if they have 1160 * already been sent. skb_mstamp isn't set to 1161 * avoid wrong rtt estimation. 1162 */ 1163 if (tp->repair) 1164 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; 1165 } 1166 1167 /* Try to append data to the end of skb. */ 1168 if (copy > msg_data_left(msg)) 1169 copy = msg_data_left(msg); 1170 1171 /* Where to copy to? */ 1172 if (skb_availroom(skb) > 0) { 1173 /* We have some space in skb head. Superb! */ 1174 copy = min_t(int, copy, skb_availroom(skb)); 1175 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy); 1176 if (err) 1177 goto do_fault; 1178 } else { 1179 bool merge = true; 1180 int i = skb_shinfo(skb)->nr_frags; 1181 struct page_frag *pfrag = sk_page_frag(sk); 1182 1183 if (!sk_page_frag_refill(sk, pfrag)) 1184 goto wait_for_memory; 1185 1186 if (!skb_can_coalesce(skb, i, pfrag->page, 1187 pfrag->offset)) { 1188 if (i == MAX_SKB_FRAGS || !sg) { 1189 tcp_mark_push(tp, skb); 1190 goto new_segment; 1191 } 1192 merge = false; 1193 } 1194 1195 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1196 1197 if (!sk_wmem_schedule(sk, copy)) 1198 goto wait_for_memory; 1199 1200 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, 1201 pfrag->page, 1202 pfrag->offset, 1203 copy); 1204 if (err) 1205 goto do_error; 1206 1207 /* Update the skb. */ 1208 if (merge) { 1209 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1210 } else { 1211 skb_fill_page_desc(skb, i, pfrag->page, 1212 pfrag->offset, copy); 1213 get_page(pfrag->page); 1214 } 1215 pfrag->offset += copy; 1216 } 1217 1218 if (!copied) 1219 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1220 1221 tp->write_seq += copy; 1222 TCP_SKB_CB(skb)->end_seq += copy; 1223 tcp_skb_pcount_set(skb, 0); 1224 1225 copied += copy; 1226 if (!msg_data_left(msg)) { 1227 tcp_tx_timestamp(sk, skb); 1228 goto out; 1229 } 1230 1231 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) 1232 continue; 1233 1234 if (forced_push(tp)) { 1235 tcp_mark_push(tp, skb); 1236 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1237 } else if (skb == tcp_send_head(sk)) 1238 tcp_push_one(sk, mss_now); 1239 continue; 1240 1241 wait_for_sndbuf: 1242 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1243 wait_for_memory: 1244 if (copied) 1245 tcp_push(sk, flags & ~MSG_MORE, mss_now, 1246 TCP_NAGLE_PUSH, size_goal); 1247 1248 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1249 goto do_error; 1250 1251 mss_now = tcp_send_mss(sk, &size_goal, flags); 1252 } 1253 1254 out: 1255 if (copied) 1256 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 1257 out_nopush: 1258 release_sock(sk); 1259 return copied + copied_syn; 1260 1261 do_fault: 1262 if (!skb->len) { 1263 tcp_unlink_write_queue(skb, sk); 1264 /* It is the one place in all of TCP, except connection 1265 * reset, where we can be unlinking the send_head. 1266 */ 1267 tcp_check_send_head(sk, skb); 1268 sk_wmem_free_skb(sk, skb); 1269 } 1270 1271 do_error: 1272 if (copied + copied_syn) 1273 goto out; 1274 out_err: 1275 err = sk_stream_error(sk, flags, err); 1276 release_sock(sk); 1277 return err; 1278 } 1279 EXPORT_SYMBOL(tcp_sendmsg); 1280 1281 /* 1282 * Handle reading urgent data. BSD has very simple semantics for 1283 * this, no blocking and very strange errors 8) 1284 */ 1285 1286 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1287 { 1288 struct tcp_sock *tp = tcp_sk(sk); 1289 1290 /* No URG data to read. */ 1291 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1292 tp->urg_data == TCP_URG_READ) 1293 return -EINVAL; /* Yes this is right ! */ 1294 1295 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1296 return -ENOTCONN; 1297 1298 if (tp->urg_data & TCP_URG_VALID) { 1299 int err = 0; 1300 char c = tp->urg_data; 1301 1302 if (!(flags & MSG_PEEK)) 1303 tp->urg_data = TCP_URG_READ; 1304 1305 /* Read urgent data. */ 1306 msg->msg_flags |= MSG_OOB; 1307 1308 if (len > 0) { 1309 if (!(flags & MSG_TRUNC)) 1310 err = memcpy_to_msg(msg, &c, 1); 1311 len = 1; 1312 } else 1313 msg->msg_flags |= MSG_TRUNC; 1314 1315 return err ? -EFAULT : len; 1316 } 1317 1318 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1319 return 0; 1320 1321 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1322 * the available implementations agree in this case: 1323 * this call should never block, independent of the 1324 * blocking state of the socket. 1325 * Mike <pall@rz.uni-karlsruhe.de> 1326 */ 1327 return -EAGAIN; 1328 } 1329 1330 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 1331 { 1332 struct sk_buff *skb; 1333 int copied = 0, err = 0; 1334 1335 /* XXX -- need to support SO_PEEK_OFF */ 1336 1337 skb_queue_walk(&sk->sk_write_queue, skb) { 1338 err = skb_copy_datagram_msg(skb, 0, msg, skb->len); 1339 if (err) 1340 break; 1341 1342 copied += skb->len; 1343 } 1344 1345 return err ?: copied; 1346 } 1347 1348 /* Clean up the receive buffer for full frames taken by the user, 1349 * then send an ACK if necessary. COPIED is the number of bytes 1350 * tcp_recvmsg has given to the user so far, it speeds up the 1351 * calculation of whether or not we must ACK for the sake of 1352 * a window update. 1353 */ 1354 static void tcp_cleanup_rbuf(struct sock *sk, int copied) 1355 { 1356 struct tcp_sock *tp = tcp_sk(sk); 1357 bool time_to_ack = false; 1358 1359 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1360 1361 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1362 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1363 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1364 1365 if (inet_csk_ack_scheduled(sk)) { 1366 const struct inet_connection_sock *icsk = inet_csk(sk); 1367 /* Delayed ACKs frequently hit locked sockets during bulk 1368 * receive. */ 1369 if (icsk->icsk_ack.blocked || 1370 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1371 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1372 /* 1373 * If this read emptied read buffer, we send ACK, if 1374 * connection is not bidirectional, user drained 1375 * receive buffer and there was a small segment 1376 * in queue. 1377 */ 1378 (copied > 0 && 1379 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1380 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1381 !icsk->icsk_ack.pingpong)) && 1382 !atomic_read(&sk->sk_rmem_alloc))) 1383 time_to_ack = true; 1384 } 1385 1386 /* We send an ACK if we can now advertise a non-zero window 1387 * which has been raised "significantly". 1388 * 1389 * Even if window raised up to infinity, do not send window open ACK 1390 * in states, where we will not receive more. It is useless. 1391 */ 1392 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1393 __u32 rcv_window_now = tcp_receive_window(tp); 1394 1395 /* Optimize, __tcp_select_window() is not cheap. */ 1396 if (2*rcv_window_now <= tp->window_clamp) { 1397 __u32 new_window = __tcp_select_window(sk); 1398 1399 /* Send ACK now, if this read freed lots of space 1400 * in our buffer. Certainly, new_window is new window. 1401 * We can advertise it now, if it is not less than current one. 1402 * "Lots" means "at least twice" here. 1403 */ 1404 if (new_window && new_window >= 2 * rcv_window_now) 1405 time_to_ack = true; 1406 } 1407 } 1408 if (time_to_ack) 1409 tcp_send_ack(sk); 1410 } 1411 1412 static void tcp_prequeue_process(struct sock *sk) 1413 { 1414 struct sk_buff *skb; 1415 struct tcp_sock *tp = tcp_sk(sk); 1416 1417 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1418 1419 /* RX process wants to run with disabled BHs, though it is not 1420 * necessary */ 1421 local_bh_disable(); 1422 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1423 sk_backlog_rcv(sk, skb); 1424 local_bh_enable(); 1425 1426 /* Clear memory counter. */ 1427 tp->ucopy.memory = 0; 1428 } 1429 1430 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1431 { 1432 struct sk_buff *skb; 1433 u32 offset; 1434 1435 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) { 1436 offset = seq - TCP_SKB_CB(skb)->seq; 1437 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1438 offset--; 1439 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) { 1440 *off = offset; 1441 return skb; 1442 } 1443 /* This looks weird, but this can happen if TCP collapsing 1444 * splitted a fat GRO packet, while we released socket lock 1445 * in skb_splice_bits() 1446 */ 1447 sk_eat_skb(sk, skb); 1448 } 1449 return NULL; 1450 } 1451 1452 /* 1453 * This routine provides an alternative to tcp_recvmsg() for routines 1454 * that would like to handle copying from skbuffs directly in 'sendfile' 1455 * fashion. 1456 * Note: 1457 * - It is assumed that the socket was locked by the caller. 1458 * - The routine does not block. 1459 * - At present, there is no support for reading OOB data 1460 * or for 'peeking' the socket using this routine 1461 * (although both would be easy to implement). 1462 */ 1463 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1464 sk_read_actor_t recv_actor) 1465 { 1466 struct sk_buff *skb; 1467 struct tcp_sock *tp = tcp_sk(sk); 1468 u32 seq = tp->copied_seq; 1469 u32 offset; 1470 int copied = 0; 1471 1472 if (sk->sk_state == TCP_LISTEN) 1473 return -ENOTCONN; 1474 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1475 if (offset < skb->len) { 1476 int used; 1477 size_t len; 1478 1479 len = skb->len - offset; 1480 /* Stop reading if we hit a patch of urgent data */ 1481 if (tp->urg_data) { 1482 u32 urg_offset = tp->urg_seq - seq; 1483 if (urg_offset < len) 1484 len = urg_offset; 1485 if (!len) 1486 break; 1487 } 1488 used = recv_actor(desc, skb, offset, len); 1489 if (used <= 0) { 1490 if (!copied) 1491 copied = used; 1492 break; 1493 } else if (used <= len) { 1494 seq += used; 1495 copied += used; 1496 offset += used; 1497 } 1498 /* If recv_actor drops the lock (e.g. TCP splice 1499 * receive) the skb pointer might be invalid when 1500 * getting here: tcp_collapse might have deleted it 1501 * while aggregating skbs from the socket queue. 1502 */ 1503 skb = tcp_recv_skb(sk, seq - 1, &offset); 1504 if (!skb) 1505 break; 1506 /* TCP coalescing might have appended data to the skb. 1507 * Try to splice more frags 1508 */ 1509 if (offset + 1 != skb->len) 1510 continue; 1511 } 1512 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { 1513 sk_eat_skb(sk, skb); 1514 ++seq; 1515 break; 1516 } 1517 sk_eat_skb(sk, skb); 1518 if (!desc->count) 1519 break; 1520 tp->copied_seq = seq; 1521 } 1522 tp->copied_seq = seq; 1523 1524 tcp_rcv_space_adjust(sk); 1525 1526 /* Clean up data we have read: This will do ACK frames. */ 1527 if (copied > 0) { 1528 tcp_recv_skb(sk, seq, &offset); 1529 tcp_cleanup_rbuf(sk, copied); 1530 } 1531 return copied; 1532 } 1533 EXPORT_SYMBOL(tcp_read_sock); 1534 1535 /* 1536 * This routine copies from a sock struct into the user buffer. 1537 * 1538 * Technical note: in 2.3 we work on _locked_ socket, so that 1539 * tricks with *seq access order and skb->users are not required. 1540 * Probably, code can be easily improved even more. 1541 */ 1542 1543 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 1544 int flags, int *addr_len) 1545 { 1546 struct tcp_sock *tp = tcp_sk(sk); 1547 int copied = 0; 1548 u32 peek_seq; 1549 u32 *seq; 1550 unsigned long used; 1551 int err; 1552 int target; /* Read at least this many bytes */ 1553 long timeo; 1554 struct task_struct *user_recv = NULL; 1555 struct sk_buff *skb; 1556 u32 urg_hole = 0; 1557 1558 if (unlikely(flags & MSG_ERRQUEUE)) 1559 return inet_recv_error(sk, msg, len, addr_len); 1560 1561 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) && 1562 (sk->sk_state == TCP_ESTABLISHED)) 1563 sk_busy_loop(sk, nonblock); 1564 1565 lock_sock(sk); 1566 1567 err = -ENOTCONN; 1568 if (sk->sk_state == TCP_LISTEN) 1569 goto out; 1570 1571 timeo = sock_rcvtimeo(sk, nonblock); 1572 1573 /* Urgent data needs to be handled specially. */ 1574 if (flags & MSG_OOB) 1575 goto recv_urg; 1576 1577 if (unlikely(tp->repair)) { 1578 err = -EPERM; 1579 if (!(flags & MSG_PEEK)) 1580 goto out; 1581 1582 if (tp->repair_queue == TCP_SEND_QUEUE) 1583 goto recv_sndq; 1584 1585 err = -EINVAL; 1586 if (tp->repair_queue == TCP_NO_QUEUE) 1587 goto out; 1588 1589 /* 'common' recv queue MSG_PEEK-ing */ 1590 } 1591 1592 seq = &tp->copied_seq; 1593 if (flags & MSG_PEEK) { 1594 peek_seq = tp->copied_seq; 1595 seq = &peek_seq; 1596 } 1597 1598 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1599 1600 do { 1601 u32 offset; 1602 1603 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1604 if (tp->urg_data && tp->urg_seq == *seq) { 1605 if (copied) 1606 break; 1607 if (signal_pending(current)) { 1608 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1609 break; 1610 } 1611 } 1612 1613 /* Next get a buffer. */ 1614 1615 skb_queue_walk(&sk->sk_receive_queue, skb) { 1616 /* Now that we have two receive queues this 1617 * shouldn't happen. 1618 */ 1619 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1620 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1621 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1622 flags)) 1623 break; 1624 1625 offset = *seq - TCP_SKB_CB(skb)->seq; 1626 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1627 offset--; 1628 if (offset < skb->len) 1629 goto found_ok_skb; 1630 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1631 goto found_fin_ok; 1632 WARN(!(flags & MSG_PEEK), 1633 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1634 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1635 } 1636 1637 /* Well, if we have backlog, try to process it now yet. */ 1638 1639 if (copied >= target && !sk->sk_backlog.tail) 1640 break; 1641 1642 if (copied) { 1643 if (sk->sk_err || 1644 sk->sk_state == TCP_CLOSE || 1645 (sk->sk_shutdown & RCV_SHUTDOWN) || 1646 !timeo || 1647 signal_pending(current)) 1648 break; 1649 } else { 1650 if (sock_flag(sk, SOCK_DONE)) 1651 break; 1652 1653 if (sk->sk_err) { 1654 copied = sock_error(sk); 1655 break; 1656 } 1657 1658 if (sk->sk_shutdown & RCV_SHUTDOWN) 1659 break; 1660 1661 if (sk->sk_state == TCP_CLOSE) { 1662 if (!sock_flag(sk, SOCK_DONE)) { 1663 /* This occurs when user tries to read 1664 * from never connected socket. 1665 */ 1666 copied = -ENOTCONN; 1667 break; 1668 } 1669 break; 1670 } 1671 1672 if (!timeo) { 1673 copied = -EAGAIN; 1674 break; 1675 } 1676 1677 if (signal_pending(current)) { 1678 copied = sock_intr_errno(timeo); 1679 break; 1680 } 1681 } 1682 1683 tcp_cleanup_rbuf(sk, copied); 1684 1685 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1686 /* Install new reader */ 1687 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1688 user_recv = current; 1689 tp->ucopy.task = user_recv; 1690 tp->ucopy.msg = msg; 1691 } 1692 1693 tp->ucopy.len = len; 1694 1695 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1696 !(flags & (MSG_PEEK | MSG_TRUNC))); 1697 1698 /* Ugly... If prequeue is not empty, we have to 1699 * process it before releasing socket, otherwise 1700 * order will be broken at second iteration. 1701 * More elegant solution is required!!! 1702 * 1703 * Look: we have the following (pseudo)queues: 1704 * 1705 * 1. packets in flight 1706 * 2. backlog 1707 * 3. prequeue 1708 * 4. receive_queue 1709 * 1710 * Each queue can be processed only if the next ones 1711 * are empty. At this point we have empty receive_queue. 1712 * But prequeue _can_ be not empty after 2nd iteration, 1713 * when we jumped to start of loop because backlog 1714 * processing added something to receive_queue. 1715 * We cannot release_sock(), because backlog contains 1716 * packets arrived _after_ prequeued ones. 1717 * 1718 * Shortly, algorithm is clear --- to process all 1719 * the queues in order. We could make it more directly, 1720 * requeueing packets from backlog to prequeue, if 1721 * is not empty. It is more elegant, but eats cycles, 1722 * unfortunately. 1723 */ 1724 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1725 goto do_prequeue; 1726 1727 /* __ Set realtime policy in scheduler __ */ 1728 } 1729 1730 if (copied >= target) { 1731 /* Do not sleep, just process backlog. */ 1732 release_sock(sk); 1733 lock_sock(sk); 1734 } else 1735 sk_wait_data(sk, &timeo); 1736 1737 if (user_recv) { 1738 int chunk; 1739 1740 /* __ Restore normal policy in scheduler __ */ 1741 1742 if ((chunk = len - tp->ucopy.len) != 0) { 1743 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1744 len -= chunk; 1745 copied += chunk; 1746 } 1747 1748 if (tp->rcv_nxt == tp->copied_seq && 1749 !skb_queue_empty(&tp->ucopy.prequeue)) { 1750 do_prequeue: 1751 tcp_prequeue_process(sk); 1752 1753 if ((chunk = len - tp->ucopy.len) != 0) { 1754 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1755 len -= chunk; 1756 copied += chunk; 1757 } 1758 } 1759 } 1760 if ((flags & MSG_PEEK) && 1761 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1762 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n", 1763 current->comm, 1764 task_pid_nr(current)); 1765 peek_seq = tp->copied_seq; 1766 } 1767 continue; 1768 1769 found_ok_skb: 1770 /* Ok so how much can we use? */ 1771 used = skb->len - offset; 1772 if (len < used) 1773 used = len; 1774 1775 /* Do we have urgent data here? */ 1776 if (tp->urg_data) { 1777 u32 urg_offset = tp->urg_seq - *seq; 1778 if (urg_offset < used) { 1779 if (!urg_offset) { 1780 if (!sock_flag(sk, SOCK_URGINLINE)) { 1781 ++*seq; 1782 urg_hole++; 1783 offset++; 1784 used--; 1785 if (!used) 1786 goto skip_copy; 1787 } 1788 } else 1789 used = urg_offset; 1790 } 1791 } 1792 1793 if (!(flags & MSG_TRUNC)) { 1794 err = skb_copy_datagram_msg(skb, offset, msg, used); 1795 if (err) { 1796 /* Exception. Bailout! */ 1797 if (!copied) 1798 copied = -EFAULT; 1799 break; 1800 } 1801 } 1802 1803 *seq += used; 1804 copied += used; 1805 len -= used; 1806 1807 tcp_rcv_space_adjust(sk); 1808 1809 skip_copy: 1810 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1811 tp->urg_data = 0; 1812 tcp_fast_path_check(sk); 1813 } 1814 if (used + offset < skb->len) 1815 continue; 1816 1817 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1818 goto found_fin_ok; 1819 if (!(flags & MSG_PEEK)) 1820 sk_eat_skb(sk, skb); 1821 continue; 1822 1823 found_fin_ok: 1824 /* Process the FIN. */ 1825 ++*seq; 1826 if (!(flags & MSG_PEEK)) 1827 sk_eat_skb(sk, skb); 1828 break; 1829 } while (len > 0); 1830 1831 if (user_recv) { 1832 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1833 int chunk; 1834 1835 tp->ucopy.len = copied > 0 ? len : 0; 1836 1837 tcp_prequeue_process(sk); 1838 1839 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1840 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1841 len -= chunk; 1842 copied += chunk; 1843 } 1844 } 1845 1846 tp->ucopy.task = NULL; 1847 tp->ucopy.len = 0; 1848 } 1849 1850 /* According to UNIX98, msg_name/msg_namelen are ignored 1851 * on connected socket. I was just happy when found this 8) --ANK 1852 */ 1853 1854 /* Clean up data we have read: This will do ACK frames. */ 1855 tcp_cleanup_rbuf(sk, copied); 1856 1857 release_sock(sk); 1858 return copied; 1859 1860 out: 1861 release_sock(sk); 1862 return err; 1863 1864 recv_urg: 1865 err = tcp_recv_urg(sk, msg, len, flags); 1866 goto out; 1867 1868 recv_sndq: 1869 err = tcp_peek_sndq(sk, msg, len); 1870 goto out; 1871 } 1872 EXPORT_SYMBOL(tcp_recvmsg); 1873 1874 void tcp_set_state(struct sock *sk, int state) 1875 { 1876 int oldstate = sk->sk_state; 1877 1878 switch (state) { 1879 case TCP_ESTABLISHED: 1880 if (oldstate != TCP_ESTABLISHED) 1881 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1882 break; 1883 1884 case TCP_CLOSE: 1885 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1886 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1887 1888 sk->sk_prot->unhash(sk); 1889 if (inet_csk(sk)->icsk_bind_hash && 1890 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1891 inet_put_port(sk); 1892 /* fall through */ 1893 default: 1894 if (oldstate == TCP_ESTABLISHED) 1895 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1896 } 1897 1898 /* Change state AFTER socket is unhashed to avoid closed 1899 * socket sitting in hash tables. 1900 */ 1901 sk->sk_state = state; 1902 1903 #ifdef STATE_TRACE 1904 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1905 #endif 1906 } 1907 EXPORT_SYMBOL_GPL(tcp_set_state); 1908 1909 /* 1910 * State processing on a close. This implements the state shift for 1911 * sending our FIN frame. Note that we only send a FIN for some 1912 * states. A shutdown() may have already sent the FIN, or we may be 1913 * closed. 1914 */ 1915 1916 static const unsigned char new_state[16] = { 1917 /* current state: new state: action: */ 1918 [0 /* (Invalid) */] = TCP_CLOSE, 1919 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1920 [TCP_SYN_SENT] = TCP_CLOSE, 1921 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1922 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 1923 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 1924 [TCP_TIME_WAIT] = TCP_CLOSE, 1925 [TCP_CLOSE] = TCP_CLOSE, 1926 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 1927 [TCP_LAST_ACK] = TCP_LAST_ACK, 1928 [TCP_LISTEN] = TCP_CLOSE, 1929 [TCP_CLOSING] = TCP_CLOSING, 1930 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 1931 }; 1932 1933 static int tcp_close_state(struct sock *sk) 1934 { 1935 int next = (int)new_state[sk->sk_state]; 1936 int ns = next & TCP_STATE_MASK; 1937 1938 tcp_set_state(sk, ns); 1939 1940 return next & TCP_ACTION_FIN; 1941 } 1942 1943 /* 1944 * Shutdown the sending side of a connection. Much like close except 1945 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1946 */ 1947 1948 void tcp_shutdown(struct sock *sk, int how) 1949 { 1950 /* We need to grab some memory, and put together a FIN, 1951 * and then put it into the queue to be sent. 1952 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1953 */ 1954 if (!(how & SEND_SHUTDOWN)) 1955 return; 1956 1957 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1958 if ((1 << sk->sk_state) & 1959 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1960 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1961 /* Clear out any half completed packets. FIN if needed. */ 1962 if (tcp_close_state(sk)) 1963 tcp_send_fin(sk); 1964 } 1965 } 1966 EXPORT_SYMBOL(tcp_shutdown); 1967 1968 bool tcp_check_oom(struct sock *sk, int shift) 1969 { 1970 bool too_many_orphans, out_of_socket_memory; 1971 1972 too_many_orphans = tcp_too_many_orphans(sk, shift); 1973 out_of_socket_memory = tcp_out_of_memory(sk); 1974 1975 if (too_many_orphans) 1976 net_info_ratelimited("too many orphaned sockets\n"); 1977 if (out_of_socket_memory) 1978 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n"); 1979 return too_many_orphans || out_of_socket_memory; 1980 } 1981 1982 void tcp_close(struct sock *sk, long timeout) 1983 { 1984 struct sk_buff *skb; 1985 int data_was_unread = 0; 1986 int state; 1987 1988 lock_sock(sk); 1989 sk->sk_shutdown = SHUTDOWN_MASK; 1990 1991 if (sk->sk_state == TCP_LISTEN) { 1992 tcp_set_state(sk, TCP_CLOSE); 1993 1994 /* Special case. */ 1995 inet_csk_listen_stop(sk); 1996 1997 goto adjudge_to_death; 1998 } 1999 2000 /* We need to flush the recv. buffs. We do this only on the 2001 * descriptor close, not protocol-sourced closes, because the 2002 * reader process may not have drained the data yet! 2003 */ 2004 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 2005 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq; 2006 2007 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 2008 len--; 2009 data_was_unread += len; 2010 __kfree_skb(skb); 2011 } 2012 2013 sk_mem_reclaim(sk); 2014 2015 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 2016 if (sk->sk_state == TCP_CLOSE) 2017 goto adjudge_to_death; 2018 2019 /* As outlined in RFC 2525, section 2.17, we send a RST here because 2020 * data was lost. To witness the awful effects of the old behavior of 2021 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 2022 * GET in an FTP client, suspend the process, wait for the client to 2023 * advertise a zero window, then kill -9 the FTP client, wheee... 2024 * Note: timeout is always zero in such a case. 2025 */ 2026 if (unlikely(tcp_sk(sk)->repair)) { 2027 sk->sk_prot->disconnect(sk, 0); 2028 } else if (data_was_unread) { 2029 /* Unread data was tossed, zap the connection. */ 2030 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 2031 tcp_set_state(sk, TCP_CLOSE); 2032 tcp_send_active_reset(sk, sk->sk_allocation); 2033 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 2034 /* Check zero linger _after_ checking for unread data. */ 2035 sk->sk_prot->disconnect(sk, 0); 2036 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 2037 } else if (tcp_close_state(sk)) { 2038 /* We FIN if the application ate all the data before 2039 * zapping the connection. 2040 */ 2041 2042 /* RED-PEN. Formally speaking, we have broken TCP state 2043 * machine. State transitions: 2044 * 2045 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 2046 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 2047 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 2048 * 2049 * are legal only when FIN has been sent (i.e. in window), 2050 * rather than queued out of window. Purists blame. 2051 * 2052 * F.e. "RFC state" is ESTABLISHED, 2053 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 2054 * 2055 * The visible declinations are that sometimes 2056 * we enter time-wait state, when it is not required really 2057 * (harmless), do not send active resets, when they are 2058 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 2059 * they look as CLOSING or LAST_ACK for Linux) 2060 * Probably, I missed some more holelets. 2061 * --ANK 2062 * XXX (TFO) - To start off we don't support SYN+ACK+FIN 2063 * in a single packet! (May consider it later but will 2064 * probably need API support or TCP_CORK SYN-ACK until 2065 * data is written and socket is closed.) 2066 */ 2067 tcp_send_fin(sk); 2068 } 2069 2070 sk_stream_wait_close(sk, timeout); 2071 2072 adjudge_to_death: 2073 state = sk->sk_state; 2074 sock_hold(sk); 2075 sock_orphan(sk); 2076 2077 /* It is the last release_sock in its life. It will remove backlog. */ 2078 release_sock(sk); 2079 2080 2081 /* Now socket is owned by kernel and we acquire BH lock 2082 to finish close. No need to check for user refs. 2083 */ 2084 local_bh_disable(); 2085 bh_lock_sock(sk); 2086 WARN_ON(sock_owned_by_user(sk)); 2087 2088 percpu_counter_inc(sk->sk_prot->orphan_count); 2089 2090 /* Have we already been destroyed by a softirq or backlog? */ 2091 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 2092 goto out; 2093 2094 /* This is a (useful) BSD violating of the RFC. There is a 2095 * problem with TCP as specified in that the other end could 2096 * keep a socket open forever with no application left this end. 2097 * We use a 1 minute timeout (about the same as BSD) then kill 2098 * our end. If they send after that then tough - BUT: long enough 2099 * that we won't make the old 4*rto = almost no time - whoops 2100 * reset mistake. 2101 * 2102 * Nope, it was not mistake. It is really desired behaviour 2103 * f.e. on http servers, when such sockets are useless, but 2104 * consume significant resources. Let's do it with special 2105 * linger2 option. --ANK 2106 */ 2107 2108 if (sk->sk_state == TCP_FIN_WAIT2) { 2109 struct tcp_sock *tp = tcp_sk(sk); 2110 if (tp->linger2 < 0) { 2111 tcp_set_state(sk, TCP_CLOSE); 2112 tcp_send_active_reset(sk, GFP_ATOMIC); 2113 NET_INC_STATS_BH(sock_net(sk), 2114 LINUX_MIB_TCPABORTONLINGER); 2115 } else { 2116 const int tmo = tcp_fin_time(sk); 2117 2118 if (tmo > TCP_TIMEWAIT_LEN) { 2119 inet_csk_reset_keepalive_timer(sk, 2120 tmo - TCP_TIMEWAIT_LEN); 2121 } else { 2122 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2123 goto out; 2124 } 2125 } 2126 } 2127 if (sk->sk_state != TCP_CLOSE) { 2128 sk_mem_reclaim(sk); 2129 if (tcp_check_oom(sk, 0)) { 2130 tcp_set_state(sk, TCP_CLOSE); 2131 tcp_send_active_reset(sk, GFP_ATOMIC); 2132 NET_INC_STATS_BH(sock_net(sk), 2133 LINUX_MIB_TCPABORTONMEMORY); 2134 } 2135 } 2136 2137 if (sk->sk_state == TCP_CLOSE) { 2138 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2139 /* We could get here with a non-NULL req if the socket is 2140 * aborted (e.g., closed with unread data) before 3WHS 2141 * finishes. 2142 */ 2143 if (req) 2144 reqsk_fastopen_remove(sk, req, false); 2145 inet_csk_destroy_sock(sk); 2146 } 2147 /* Otherwise, socket is reprieved until protocol close. */ 2148 2149 out: 2150 bh_unlock_sock(sk); 2151 local_bh_enable(); 2152 sock_put(sk); 2153 } 2154 EXPORT_SYMBOL(tcp_close); 2155 2156 /* These states need RST on ABORT according to RFC793 */ 2157 2158 static inline bool tcp_need_reset(int state) 2159 { 2160 return (1 << state) & 2161 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2162 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2163 } 2164 2165 int tcp_disconnect(struct sock *sk, int flags) 2166 { 2167 struct inet_sock *inet = inet_sk(sk); 2168 struct inet_connection_sock *icsk = inet_csk(sk); 2169 struct tcp_sock *tp = tcp_sk(sk); 2170 int err = 0; 2171 int old_state = sk->sk_state; 2172 2173 if (old_state != TCP_CLOSE) 2174 tcp_set_state(sk, TCP_CLOSE); 2175 2176 /* ABORT function of RFC793 */ 2177 if (old_state == TCP_LISTEN) { 2178 inet_csk_listen_stop(sk); 2179 } else if (unlikely(tp->repair)) { 2180 sk->sk_err = ECONNABORTED; 2181 } else if (tcp_need_reset(old_state) || 2182 (tp->snd_nxt != tp->write_seq && 2183 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2184 /* The last check adjusts for discrepancy of Linux wrt. RFC 2185 * states 2186 */ 2187 tcp_send_active_reset(sk, gfp_any()); 2188 sk->sk_err = ECONNRESET; 2189 } else if (old_state == TCP_SYN_SENT) 2190 sk->sk_err = ECONNRESET; 2191 2192 tcp_clear_xmit_timers(sk); 2193 __skb_queue_purge(&sk->sk_receive_queue); 2194 tcp_write_queue_purge(sk); 2195 __skb_queue_purge(&tp->out_of_order_queue); 2196 2197 inet->inet_dport = 0; 2198 2199 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2200 inet_reset_saddr(sk); 2201 2202 sk->sk_shutdown = 0; 2203 sock_reset_flag(sk, SOCK_DONE); 2204 tp->srtt_us = 0; 2205 if ((tp->write_seq += tp->max_window + 2) == 0) 2206 tp->write_seq = 1; 2207 icsk->icsk_backoff = 0; 2208 tp->snd_cwnd = 2; 2209 icsk->icsk_probes_out = 0; 2210 tp->packets_out = 0; 2211 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2212 tp->snd_cwnd_cnt = 0; 2213 tp->window_clamp = 0; 2214 tcp_set_ca_state(sk, TCP_CA_Open); 2215 tcp_clear_retrans(tp); 2216 inet_csk_delack_init(sk); 2217 tcp_init_send_head(sk); 2218 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2219 __sk_dst_reset(sk); 2220 2221 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2222 2223 sk->sk_error_report(sk); 2224 return err; 2225 } 2226 EXPORT_SYMBOL(tcp_disconnect); 2227 2228 void tcp_sock_destruct(struct sock *sk) 2229 { 2230 inet_sock_destruct(sk); 2231 2232 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq); 2233 } 2234 2235 static inline bool tcp_can_repair_sock(const struct sock *sk) 2236 { 2237 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) && 2238 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED)); 2239 } 2240 2241 static int tcp_repair_options_est(struct tcp_sock *tp, 2242 struct tcp_repair_opt __user *optbuf, unsigned int len) 2243 { 2244 struct tcp_repair_opt opt; 2245 2246 while (len >= sizeof(opt)) { 2247 if (copy_from_user(&opt, optbuf, sizeof(opt))) 2248 return -EFAULT; 2249 2250 optbuf++; 2251 len -= sizeof(opt); 2252 2253 switch (opt.opt_code) { 2254 case TCPOPT_MSS: 2255 tp->rx_opt.mss_clamp = opt.opt_val; 2256 break; 2257 case TCPOPT_WINDOW: 2258 { 2259 u16 snd_wscale = opt.opt_val & 0xFFFF; 2260 u16 rcv_wscale = opt.opt_val >> 16; 2261 2262 if (snd_wscale > 14 || rcv_wscale > 14) 2263 return -EFBIG; 2264 2265 tp->rx_opt.snd_wscale = snd_wscale; 2266 tp->rx_opt.rcv_wscale = rcv_wscale; 2267 tp->rx_opt.wscale_ok = 1; 2268 } 2269 break; 2270 case TCPOPT_SACK_PERM: 2271 if (opt.opt_val != 0) 2272 return -EINVAL; 2273 2274 tp->rx_opt.sack_ok |= TCP_SACK_SEEN; 2275 if (sysctl_tcp_fack) 2276 tcp_enable_fack(tp); 2277 break; 2278 case TCPOPT_TIMESTAMP: 2279 if (opt.opt_val != 0) 2280 return -EINVAL; 2281 2282 tp->rx_opt.tstamp_ok = 1; 2283 break; 2284 } 2285 } 2286 2287 return 0; 2288 } 2289 2290 /* 2291 * Socket option code for TCP. 2292 */ 2293 static int do_tcp_setsockopt(struct sock *sk, int level, 2294 int optname, char __user *optval, unsigned int optlen) 2295 { 2296 struct tcp_sock *tp = tcp_sk(sk); 2297 struct inet_connection_sock *icsk = inet_csk(sk); 2298 int val; 2299 int err = 0; 2300 2301 /* These are data/string values, all the others are ints */ 2302 switch (optname) { 2303 case TCP_CONGESTION: { 2304 char name[TCP_CA_NAME_MAX]; 2305 2306 if (optlen < 1) 2307 return -EINVAL; 2308 2309 val = strncpy_from_user(name, optval, 2310 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2311 if (val < 0) 2312 return -EFAULT; 2313 name[val] = 0; 2314 2315 lock_sock(sk); 2316 err = tcp_set_congestion_control(sk, name); 2317 release_sock(sk); 2318 return err; 2319 } 2320 default: 2321 /* fallthru */ 2322 break; 2323 } 2324 2325 if (optlen < sizeof(int)) 2326 return -EINVAL; 2327 2328 if (get_user(val, (int __user *)optval)) 2329 return -EFAULT; 2330 2331 lock_sock(sk); 2332 2333 switch (optname) { 2334 case TCP_MAXSEG: 2335 /* Values greater than interface MTU won't take effect. However 2336 * at the point when this call is done we typically don't yet 2337 * know which interface is going to be used */ 2338 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2339 err = -EINVAL; 2340 break; 2341 } 2342 tp->rx_opt.user_mss = val; 2343 break; 2344 2345 case TCP_NODELAY: 2346 if (val) { 2347 /* TCP_NODELAY is weaker than TCP_CORK, so that 2348 * this option on corked socket is remembered, but 2349 * it is not activated until cork is cleared. 2350 * 2351 * However, when TCP_NODELAY is set we make 2352 * an explicit push, which overrides even TCP_CORK 2353 * for currently queued segments. 2354 */ 2355 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2356 tcp_push_pending_frames(sk); 2357 } else { 2358 tp->nonagle &= ~TCP_NAGLE_OFF; 2359 } 2360 break; 2361 2362 case TCP_THIN_LINEAR_TIMEOUTS: 2363 if (val < 0 || val > 1) 2364 err = -EINVAL; 2365 else 2366 tp->thin_lto = val; 2367 break; 2368 2369 case TCP_THIN_DUPACK: 2370 if (val < 0 || val > 1) 2371 err = -EINVAL; 2372 else { 2373 tp->thin_dupack = val; 2374 if (tp->thin_dupack) 2375 tcp_disable_early_retrans(tp); 2376 } 2377 break; 2378 2379 case TCP_REPAIR: 2380 if (!tcp_can_repair_sock(sk)) 2381 err = -EPERM; 2382 else if (val == 1) { 2383 tp->repair = 1; 2384 sk->sk_reuse = SK_FORCE_REUSE; 2385 tp->repair_queue = TCP_NO_QUEUE; 2386 } else if (val == 0) { 2387 tp->repair = 0; 2388 sk->sk_reuse = SK_NO_REUSE; 2389 tcp_send_window_probe(sk); 2390 } else 2391 err = -EINVAL; 2392 2393 break; 2394 2395 case TCP_REPAIR_QUEUE: 2396 if (!tp->repair) 2397 err = -EPERM; 2398 else if (val < TCP_QUEUES_NR) 2399 tp->repair_queue = val; 2400 else 2401 err = -EINVAL; 2402 break; 2403 2404 case TCP_QUEUE_SEQ: 2405 if (sk->sk_state != TCP_CLOSE) 2406 err = -EPERM; 2407 else if (tp->repair_queue == TCP_SEND_QUEUE) 2408 tp->write_seq = val; 2409 else if (tp->repair_queue == TCP_RECV_QUEUE) 2410 tp->rcv_nxt = val; 2411 else 2412 err = -EINVAL; 2413 break; 2414 2415 case TCP_REPAIR_OPTIONS: 2416 if (!tp->repair) 2417 err = -EINVAL; 2418 else if (sk->sk_state == TCP_ESTABLISHED) 2419 err = tcp_repair_options_est(tp, 2420 (struct tcp_repair_opt __user *)optval, 2421 optlen); 2422 else 2423 err = -EPERM; 2424 break; 2425 2426 case TCP_CORK: 2427 /* When set indicates to always queue non-full frames. 2428 * Later the user clears this option and we transmit 2429 * any pending partial frames in the queue. This is 2430 * meant to be used alongside sendfile() to get properly 2431 * filled frames when the user (for example) must write 2432 * out headers with a write() call first and then use 2433 * sendfile to send out the data parts. 2434 * 2435 * TCP_CORK can be set together with TCP_NODELAY and it is 2436 * stronger than TCP_NODELAY. 2437 */ 2438 if (val) { 2439 tp->nonagle |= TCP_NAGLE_CORK; 2440 } else { 2441 tp->nonagle &= ~TCP_NAGLE_CORK; 2442 if (tp->nonagle&TCP_NAGLE_OFF) 2443 tp->nonagle |= TCP_NAGLE_PUSH; 2444 tcp_push_pending_frames(sk); 2445 } 2446 break; 2447 2448 case TCP_KEEPIDLE: 2449 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2450 err = -EINVAL; 2451 else { 2452 tp->keepalive_time = val * HZ; 2453 if (sock_flag(sk, SOCK_KEEPOPEN) && 2454 !((1 << sk->sk_state) & 2455 (TCPF_CLOSE | TCPF_LISTEN))) { 2456 u32 elapsed = keepalive_time_elapsed(tp); 2457 if (tp->keepalive_time > elapsed) 2458 elapsed = tp->keepalive_time - elapsed; 2459 else 2460 elapsed = 0; 2461 inet_csk_reset_keepalive_timer(sk, elapsed); 2462 } 2463 } 2464 break; 2465 case TCP_KEEPINTVL: 2466 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2467 err = -EINVAL; 2468 else 2469 tp->keepalive_intvl = val * HZ; 2470 break; 2471 case TCP_KEEPCNT: 2472 if (val < 1 || val > MAX_TCP_KEEPCNT) 2473 err = -EINVAL; 2474 else 2475 tp->keepalive_probes = val; 2476 break; 2477 case TCP_SYNCNT: 2478 if (val < 1 || val > MAX_TCP_SYNCNT) 2479 err = -EINVAL; 2480 else 2481 icsk->icsk_syn_retries = val; 2482 break; 2483 2484 case TCP_LINGER2: 2485 if (val < 0) 2486 tp->linger2 = -1; 2487 else if (val > sysctl_tcp_fin_timeout / HZ) 2488 tp->linger2 = 0; 2489 else 2490 tp->linger2 = val * HZ; 2491 break; 2492 2493 case TCP_DEFER_ACCEPT: 2494 /* Translate value in seconds to number of retransmits */ 2495 icsk->icsk_accept_queue.rskq_defer_accept = 2496 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2497 TCP_RTO_MAX / HZ); 2498 break; 2499 2500 case TCP_WINDOW_CLAMP: 2501 if (!val) { 2502 if (sk->sk_state != TCP_CLOSE) { 2503 err = -EINVAL; 2504 break; 2505 } 2506 tp->window_clamp = 0; 2507 } else 2508 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2509 SOCK_MIN_RCVBUF / 2 : val; 2510 break; 2511 2512 case TCP_QUICKACK: 2513 if (!val) { 2514 icsk->icsk_ack.pingpong = 1; 2515 } else { 2516 icsk->icsk_ack.pingpong = 0; 2517 if ((1 << sk->sk_state) & 2518 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2519 inet_csk_ack_scheduled(sk)) { 2520 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2521 tcp_cleanup_rbuf(sk, 1); 2522 if (!(val & 1)) 2523 icsk->icsk_ack.pingpong = 1; 2524 } 2525 } 2526 break; 2527 2528 #ifdef CONFIG_TCP_MD5SIG 2529 case TCP_MD5SIG: 2530 /* Read the IP->Key mappings from userspace */ 2531 err = tp->af_specific->md5_parse(sk, optval, optlen); 2532 break; 2533 #endif 2534 case TCP_USER_TIMEOUT: 2535 /* Cap the max time in ms TCP will retry or probe the window 2536 * before giving up and aborting (ETIMEDOUT) a connection. 2537 */ 2538 if (val < 0) 2539 err = -EINVAL; 2540 else 2541 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2542 break; 2543 2544 case TCP_FASTOPEN: 2545 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE | 2546 TCPF_LISTEN))) 2547 err = fastopen_init_queue(sk, val); 2548 else 2549 err = -EINVAL; 2550 break; 2551 case TCP_TIMESTAMP: 2552 if (!tp->repair) 2553 err = -EPERM; 2554 else 2555 tp->tsoffset = val - tcp_time_stamp; 2556 break; 2557 case TCP_NOTSENT_LOWAT: 2558 tp->notsent_lowat = val; 2559 sk->sk_write_space(sk); 2560 break; 2561 default: 2562 err = -ENOPROTOOPT; 2563 break; 2564 } 2565 2566 release_sock(sk); 2567 return err; 2568 } 2569 2570 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2571 unsigned int optlen) 2572 { 2573 const struct inet_connection_sock *icsk = inet_csk(sk); 2574 2575 if (level != SOL_TCP) 2576 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2577 optval, optlen); 2578 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2579 } 2580 EXPORT_SYMBOL(tcp_setsockopt); 2581 2582 #ifdef CONFIG_COMPAT 2583 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2584 char __user *optval, unsigned int optlen) 2585 { 2586 if (level != SOL_TCP) 2587 return inet_csk_compat_setsockopt(sk, level, optname, 2588 optval, optlen); 2589 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2590 } 2591 EXPORT_SYMBOL(compat_tcp_setsockopt); 2592 #endif 2593 2594 /* Return information about state of tcp endpoint in API format. */ 2595 void tcp_get_info(const struct sock *sk, struct tcp_info *info) 2596 { 2597 const struct tcp_sock *tp = tcp_sk(sk); 2598 const struct inet_connection_sock *icsk = inet_csk(sk); 2599 u32 now = tcp_time_stamp; 2600 u32 rate; 2601 2602 memset(info, 0, sizeof(*info)); 2603 2604 info->tcpi_state = sk->sk_state; 2605 info->tcpi_ca_state = icsk->icsk_ca_state; 2606 info->tcpi_retransmits = icsk->icsk_retransmits; 2607 info->tcpi_probes = icsk->icsk_probes_out; 2608 info->tcpi_backoff = icsk->icsk_backoff; 2609 2610 if (tp->rx_opt.tstamp_ok) 2611 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2612 if (tcp_is_sack(tp)) 2613 info->tcpi_options |= TCPI_OPT_SACK; 2614 if (tp->rx_opt.wscale_ok) { 2615 info->tcpi_options |= TCPI_OPT_WSCALE; 2616 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2617 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2618 } 2619 2620 if (tp->ecn_flags & TCP_ECN_OK) 2621 info->tcpi_options |= TCPI_OPT_ECN; 2622 if (tp->ecn_flags & TCP_ECN_SEEN) 2623 info->tcpi_options |= TCPI_OPT_ECN_SEEN; 2624 if (tp->syn_data_acked) 2625 info->tcpi_options |= TCPI_OPT_SYN_DATA; 2626 2627 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2628 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2629 info->tcpi_snd_mss = tp->mss_cache; 2630 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2631 2632 if (sk->sk_state == TCP_LISTEN) { 2633 info->tcpi_unacked = sk->sk_ack_backlog; 2634 info->tcpi_sacked = sk->sk_max_ack_backlog; 2635 } else { 2636 info->tcpi_unacked = tp->packets_out; 2637 info->tcpi_sacked = tp->sacked_out; 2638 } 2639 info->tcpi_lost = tp->lost_out; 2640 info->tcpi_retrans = tp->retrans_out; 2641 info->tcpi_fackets = tp->fackets_out; 2642 2643 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2644 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2645 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2646 2647 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2648 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2649 info->tcpi_rtt = tp->srtt_us >> 3; 2650 info->tcpi_rttvar = tp->mdev_us >> 2; 2651 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2652 info->tcpi_snd_cwnd = tp->snd_cwnd; 2653 info->tcpi_advmss = tp->advmss; 2654 info->tcpi_reordering = tp->reordering; 2655 2656 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2657 info->tcpi_rcv_space = tp->rcvq_space.space; 2658 2659 info->tcpi_total_retrans = tp->total_retrans; 2660 2661 rate = READ_ONCE(sk->sk_pacing_rate); 2662 info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL; 2663 2664 rate = READ_ONCE(sk->sk_max_pacing_rate); 2665 info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL; 2666 } 2667 EXPORT_SYMBOL_GPL(tcp_get_info); 2668 2669 static int do_tcp_getsockopt(struct sock *sk, int level, 2670 int optname, char __user *optval, int __user *optlen) 2671 { 2672 struct inet_connection_sock *icsk = inet_csk(sk); 2673 struct tcp_sock *tp = tcp_sk(sk); 2674 int val, len; 2675 2676 if (get_user(len, optlen)) 2677 return -EFAULT; 2678 2679 len = min_t(unsigned int, len, sizeof(int)); 2680 2681 if (len < 0) 2682 return -EINVAL; 2683 2684 switch (optname) { 2685 case TCP_MAXSEG: 2686 val = tp->mss_cache; 2687 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2688 val = tp->rx_opt.user_mss; 2689 if (tp->repair) 2690 val = tp->rx_opt.mss_clamp; 2691 break; 2692 case TCP_NODELAY: 2693 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2694 break; 2695 case TCP_CORK: 2696 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2697 break; 2698 case TCP_KEEPIDLE: 2699 val = keepalive_time_when(tp) / HZ; 2700 break; 2701 case TCP_KEEPINTVL: 2702 val = keepalive_intvl_when(tp) / HZ; 2703 break; 2704 case TCP_KEEPCNT: 2705 val = keepalive_probes(tp); 2706 break; 2707 case TCP_SYNCNT: 2708 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2709 break; 2710 case TCP_LINGER2: 2711 val = tp->linger2; 2712 if (val >= 0) 2713 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2714 break; 2715 case TCP_DEFER_ACCEPT: 2716 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2717 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2718 break; 2719 case TCP_WINDOW_CLAMP: 2720 val = tp->window_clamp; 2721 break; 2722 case TCP_INFO: { 2723 struct tcp_info info; 2724 2725 if (get_user(len, optlen)) 2726 return -EFAULT; 2727 2728 tcp_get_info(sk, &info); 2729 2730 len = min_t(unsigned int, len, sizeof(info)); 2731 if (put_user(len, optlen)) 2732 return -EFAULT; 2733 if (copy_to_user(optval, &info, len)) 2734 return -EFAULT; 2735 return 0; 2736 } 2737 case TCP_QUICKACK: 2738 val = !icsk->icsk_ack.pingpong; 2739 break; 2740 2741 case TCP_CONGESTION: 2742 if (get_user(len, optlen)) 2743 return -EFAULT; 2744 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2745 if (put_user(len, optlen)) 2746 return -EFAULT; 2747 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2748 return -EFAULT; 2749 return 0; 2750 2751 case TCP_THIN_LINEAR_TIMEOUTS: 2752 val = tp->thin_lto; 2753 break; 2754 case TCP_THIN_DUPACK: 2755 val = tp->thin_dupack; 2756 break; 2757 2758 case TCP_REPAIR: 2759 val = tp->repair; 2760 break; 2761 2762 case TCP_REPAIR_QUEUE: 2763 if (tp->repair) 2764 val = tp->repair_queue; 2765 else 2766 return -EINVAL; 2767 break; 2768 2769 case TCP_QUEUE_SEQ: 2770 if (tp->repair_queue == TCP_SEND_QUEUE) 2771 val = tp->write_seq; 2772 else if (tp->repair_queue == TCP_RECV_QUEUE) 2773 val = tp->rcv_nxt; 2774 else 2775 return -EINVAL; 2776 break; 2777 2778 case TCP_USER_TIMEOUT: 2779 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2780 break; 2781 2782 case TCP_FASTOPEN: 2783 if (icsk->icsk_accept_queue.fastopenq) 2784 val = icsk->icsk_accept_queue.fastopenq->max_qlen; 2785 else 2786 val = 0; 2787 break; 2788 2789 case TCP_TIMESTAMP: 2790 val = tcp_time_stamp + tp->tsoffset; 2791 break; 2792 case TCP_NOTSENT_LOWAT: 2793 val = tp->notsent_lowat; 2794 break; 2795 default: 2796 return -ENOPROTOOPT; 2797 } 2798 2799 if (put_user(len, optlen)) 2800 return -EFAULT; 2801 if (copy_to_user(optval, &val, len)) 2802 return -EFAULT; 2803 return 0; 2804 } 2805 2806 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2807 int __user *optlen) 2808 { 2809 struct inet_connection_sock *icsk = inet_csk(sk); 2810 2811 if (level != SOL_TCP) 2812 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2813 optval, optlen); 2814 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2815 } 2816 EXPORT_SYMBOL(tcp_getsockopt); 2817 2818 #ifdef CONFIG_COMPAT 2819 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2820 char __user *optval, int __user *optlen) 2821 { 2822 if (level != SOL_TCP) 2823 return inet_csk_compat_getsockopt(sk, level, optname, 2824 optval, optlen); 2825 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2826 } 2827 EXPORT_SYMBOL(compat_tcp_getsockopt); 2828 #endif 2829 2830 #ifdef CONFIG_TCP_MD5SIG 2831 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool); 2832 static DEFINE_MUTEX(tcp_md5sig_mutex); 2833 static bool tcp_md5sig_pool_populated = false; 2834 2835 static void __tcp_alloc_md5sig_pool(void) 2836 { 2837 int cpu; 2838 2839 for_each_possible_cpu(cpu) { 2840 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) { 2841 struct crypto_hash *hash; 2842 2843 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2844 if (IS_ERR_OR_NULL(hash)) 2845 return; 2846 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash; 2847 } 2848 } 2849 /* before setting tcp_md5sig_pool_populated, we must commit all writes 2850 * to memory. See smp_rmb() in tcp_get_md5sig_pool() 2851 */ 2852 smp_wmb(); 2853 tcp_md5sig_pool_populated = true; 2854 } 2855 2856 bool tcp_alloc_md5sig_pool(void) 2857 { 2858 if (unlikely(!tcp_md5sig_pool_populated)) { 2859 mutex_lock(&tcp_md5sig_mutex); 2860 2861 if (!tcp_md5sig_pool_populated) 2862 __tcp_alloc_md5sig_pool(); 2863 2864 mutex_unlock(&tcp_md5sig_mutex); 2865 } 2866 return tcp_md5sig_pool_populated; 2867 } 2868 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2869 2870 2871 /** 2872 * tcp_get_md5sig_pool - get md5sig_pool for this user 2873 * 2874 * We use percpu structure, so if we succeed, we exit with preemption 2875 * and BH disabled, to make sure another thread or softirq handling 2876 * wont try to get same context. 2877 */ 2878 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 2879 { 2880 local_bh_disable(); 2881 2882 if (tcp_md5sig_pool_populated) { 2883 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */ 2884 smp_rmb(); 2885 return this_cpu_ptr(&tcp_md5sig_pool); 2886 } 2887 local_bh_enable(); 2888 return NULL; 2889 } 2890 EXPORT_SYMBOL(tcp_get_md5sig_pool); 2891 2892 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 2893 const struct tcphdr *th) 2894 { 2895 struct scatterlist sg; 2896 struct tcphdr hdr; 2897 int err; 2898 2899 /* We are not allowed to change tcphdr, make a local copy */ 2900 memcpy(&hdr, th, sizeof(hdr)); 2901 hdr.check = 0; 2902 2903 /* options aren't included in the hash */ 2904 sg_init_one(&sg, &hdr, sizeof(hdr)); 2905 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr)); 2906 return err; 2907 } 2908 EXPORT_SYMBOL(tcp_md5_hash_header); 2909 2910 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 2911 const struct sk_buff *skb, unsigned int header_len) 2912 { 2913 struct scatterlist sg; 2914 const struct tcphdr *tp = tcp_hdr(skb); 2915 struct hash_desc *desc = &hp->md5_desc; 2916 unsigned int i; 2917 const unsigned int head_data_len = skb_headlen(skb) > header_len ? 2918 skb_headlen(skb) - header_len : 0; 2919 const struct skb_shared_info *shi = skb_shinfo(skb); 2920 struct sk_buff *frag_iter; 2921 2922 sg_init_table(&sg, 1); 2923 2924 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 2925 if (crypto_hash_update(desc, &sg, head_data_len)) 2926 return 1; 2927 2928 for (i = 0; i < shi->nr_frags; ++i) { 2929 const struct skb_frag_struct *f = &shi->frags[i]; 2930 unsigned int offset = f->page_offset; 2931 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); 2932 2933 sg_set_page(&sg, page, skb_frag_size(f), 2934 offset_in_page(offset)); 2935 if (crypto_hash_update(desc, &sg, skb_frag_size(f))) 2936 return 1; 2937 } 2938 2939 skb_walk_frags(skb, frag_iter) 2940 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 2941 return 1; 2942 2943 return 0; 2944 } 2945 EXPORT_SYMBOL(tcp_md5_hash_skb_data); 2946 2947 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) 2948 { 2949 struct scatterlist sg; 2950 2951 sg_init_one(&sg, key->key, key->keylen); 2952 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 2953 } 2954 EXPORT_SYMBOL(tcp_md5_hash_key); 2955 2956 #endif 2957 2958 void tcp_done(struct sock *sk) 2959 { 2960 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2961 2962 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2963 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 2964 2965 tcp_set_state(sk, TCP_CLOSE); 2966 tcp_clear_xmit_timers(sk); 2967 if (req) 2968 reqsk_fastopen_remove(sk, req, false); 2969 2970 sk->sk_shutdown = SHUTDOWN_MASK; 2971 2972 if (!sock_flag(sk, SOCK_DEAD)) 2973 sk->sk_state_change(sk); 2974 else 2975 inet_csk_destroy_sock(sk); 2976 } 2977 EXPORT_SYMBOL_GPL(tcp_done); 2978 2979 extern struct tcp_congestion_ops tcp_reno; 2980 2981 static __initdata unsigned long thash_entries; 2982 static int __init set_thash_entries(char *str) 2983 { 2984 ssize_t ret; 2985 2986 if (!str) 2987 return 0; 2988 2989 ret = kstrtoul(str, 0, &thash_entries); 2990 if (ret) 2991 return 0; 2992 2993 return 1; 2994 } 2995 __setup("thash_entries=", set_thash_entries); 2996 2997 static void __init tcp_init_mem(void) 2998 { 2999 unsigned long limit = nr_free_buffer_pages() / 8; 3000 limit = max(limit, 128UL); 3001 sysctl_tcp_mem[0] = limit / 4 * 3; 3002 sysctl_tcp_mem[1] = limit; 3003 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 3004 } 3005 3006 void __init tcp_init(void) 3007 { 3008 unsigned long limit; 3009 int max_rshare, max_wshare, cnt; 3010 unsigned int i; 3011 3012 sock_skb_cb_check_size(sizeof(struct tcp_skb_cb)); 3013 3014 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL); 3015 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL); 3016 tcp_hashinfo.bind_bucket_cachep = 3017 kmem_cache_create("tcp_bind_bucket", 3018 sizeof(struct inet_bind_bucket), 0, 3019 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3020 3021 /* Size and allocate the main established and bind bucket 3022 * hash tables. 3023 * 3024 * The methodology is similar to that of the buffer cache. 3025 */ 3026 tcp_hashinfo.ehash = 3027 alloc_large_system_hash("TCP established", 3028 sizeof(struct inet_ehash_bucket), 3029 thash_entries, 3030 17, /* one slot per 128 KB of memory */ 3031 0, 3032 NULL, 3033 &tcp_hashinfo.ehash_mask, 3034 0, 3035 thash_entries ? 0 : 512 * 1024); 3036 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) 3037 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3038 3039 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3040 panic("TCP: failed to alloc ehash_locks"); 3041 tcp_hashinfo.bhash = 3042 alloc_large_system_hash("TCP bind", 3043 sizeof(struct inet_bind_hashbucket), 3044 tcp_hashinfo.ehash_mask + 1, 3045 17, /* one slot per 128 KB of memory */ 3046 0, 3047 &tcp_hashinfo.bhash_size, 3048 NULL, 3049 0, 3050 64 * 1024); 3051 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size; 3052 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3053 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3054 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3055 } 3056 3057 3058 cnt = tcp_hashinfo.ehash_mask + 1; 3059 3060 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3061 sysctl_tcp_max_orphans = cnt / 2; 3062 sysctl_max_syn_backlog = max(128, cnt / 256); 3063 3064 tcp_init_mem(); 3065 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3066 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7); 3067 max_wshare = min(4UL*1024*1024, limit); 3068 max_rshare = min(6UL*1024*1024, limit); 3069 3070 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3071 sysctl_tcp_wmem[1] = 16*1024; 3072 sysctl_tcp_wmem[2] = max(64*1024, max_wshare); 3073 3074 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3075 sysctl_tcp_rmem[1] = 87380; 3076 sysctl_tcp_rmem[2] = max(87380, max_rshare); 3077 3078 pr_info("Hash tables configured (established %u bind %u)\n", 3079 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3080 3081 tcp_metrics_init(); 3082 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0); 3083 tcp_tasklet_init(); 3084 } 3085