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