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/inet_diag.h> 256 #include <linux/init.h> 257 #include <linux/fs.h> 258 #include <linux/skbuff.h> 259 #include <linux/scatterlist.h> 260 #include <linux/splice.h> 261 #include <linux/net.h> 262 #include <linux/socket.h> 263 #include <linux/random.h> 264 #include <linux/bootmem.h> 265 #include <linux/highmem.h> 266 #include <linux/swap.h> 267 #include <linux/cache.h> 268 #include <linux/err.h> 269 #include <linux/crypto.h> 270 #include <linux/time.h> 271 #include <linux/slab.h> 272 273 #include <net/icmp.h> 274 #include <net/inet_common.h> 275 #include <net/tcp.h> 276 #include <net/xfrm.h> 277 #include <net/ip.h> 278 #include <net/sock.h> 279 280 #include <asm/uaccess.h> 281 #include <asm/ioctls.h> 282 #include <net/busy_poll.h> 283 284 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 285 286 int sysctl_tcp_min_tso_segs __read_mostly = 2; 287 288 int sysctl_tcp_autocorking __read_mostly = 1; 289 290 struct percpu_counter tcp_orphan_count; 291 EXPORT_SYMBOL_GPL(tcp_orphan_count); 292 293 long sysctl_tcp_mem[3] __read_mostly; 294 int sysctl_tcp_wmem[3] __read_mostly; 295 int sysctl_tcp_rmem[3] __read_mostly; 296 297 EXPORT_SYMBOL(sysctl_tcp_mem); 298 EXPORT_SYMBOL(sysctl_tcp_rmem); 299 EXPORT_SYMBOL(sysctl_tcp_wmem); 300 301 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ 302 EXPORT_SYMBOL(tcp_memory_allocated); 303 304 /* 305 * Current number of TCP sockets. 306 */ 307 struct percpu_counter tcp_sockets_allocated; 308 EXPORT_SYMBOL(tcp_sockets_allocated); 309 310 /* 311 * TCP splice context 312 */ 313 struct tcp_splice_state { 314 struct pipe_inode_info *pipe; 315 size_t len; 316 unsigned int flags; 317 }; 318 319 /* 320 * Pressure flag: try to collapse. 321 * Technical note: it is used by multiple contexts non atomically. 322 * All the __sk_mem_schedule() is of this nature: accounting 323 * is strict, actions are advisory and have some latency. 324 */ 325 int tcp_memory_pressure __read_mostly; 326 EXPORT_SYMBOL(tcp_memory_pressure); 327 328 void tcp_enter_memory_pressure(struct sock *sk) 329 { 330 if (!tcp_memory_pressure) { 331 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 332 tcp_memory_pressure = 1; 333 } 334 } 335 EXPORT_SYMBOL(tcp_enter_memory_pressure); 336 337 /* Convert seconds to retransmits based on initial and max timeout */ 338 static u8 secs_to_retrans(int seconds, int timeout, int rto_max) 339 { 340 u8 res = 0; 341 342 if (seconds > 0) { 343 int period = timeout; 344 345 res = 1; 346 while (seconds > period && res < 255) { 347 res++; 348 timeout <<= 1; 349 if (timeout > rto_max) 350 timeout = rto_max; 351 period += timeout; 352 } 353 } 354 return res; 355 } 356 357 /* Convert retransmits to seconds based on initial and max timeout */ 358 static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 359 { 360 int period = 0; 361 362 if (retrans > 0) { 363 period = timeout; 364 while (--retrans) { 365 timeout <<= 1; 366 if (timeout > rto_max) 367 timeout = rto_max; 368 period += timeout; 369 } 370 } 371 return period; 372 } 373 374 /* Address-family independent initialization for a tcp_sock. 375 * 376 * NOTE: A lot of things set to zero explicitly by call to 377 * sk_alloc() so need not be done here. 378 */ 379 void tcp_init_sock(struct sock *sk) 380 { 381 struct inet_connection_sock *icsk = inet_csk(sk); 382 struct tcp_sock *tp = tcp_sk(sk); 383 384 __skb_queue_head_init(&tp->out_of_order_queue); 385 tcp_init_xmit_timers(sk); 386 tcp_prequeue_init(tp); 387 INIT_LIST_HEAD(&tp->tsq_node); 388 389 icsk->icsk_rto = TCP_TIMEOUT_INIT; 390 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT); 391 392 /* So many TCP implementations out there (incorrectly) count the 393 * initial SYN frame in their delayed-ACK and congestion control 394 * algorithms that we must have the following bandaid to talk 395 * efficiently to them. -DaveM 396 */ 397 tp->snd_cwnd = TCP_INIT_CWND; 398 399 /* See draft-stevens-tcpca-spec-01 for discussion of the 400 * initialization of these values. 401 */ 402 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 403 tp->snd_cwnd_clamp = ~0; 404 tp->mss_cache = TCP_MSS_DEFAULT; 405 u64_stats_init(&tp->syncp); 406 407 tp->reordering = sysctl_tcp_reordering; 408 tcp_enable_early_retrans(tp); 409 tcp_assign_congestion_control(sk); 410 411 tp->tsoffset = 0; 412 413 sk->sk_state = TCP_CLOSE; 414 415 sk->sk_write_space = sk_stream_write_space; 416 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 417 418 icsk->icsk_sync_mss = tcp_sync_mss; 419 420 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 421 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 422 423 local_bh_disable(); 424 sock_update_memcg(sk); 425 sk_sockets_allocated_inc(sk); 426 local_bh_enable(); 427 } 428 EXPORT_SYMBOL(tcp_init_sock); 429 430 static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb) 431 { 432 if (sk->sk_tsflags) { 433 struct skb_shared_info *shinfo = skb_shinfo(skb); 434 435 sock_tx_timestamp(sk, &shinfo->tx_flags); 436 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP) 437 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; 438 } 439 } 440 441 /* 442 * Wait for a TCP event. 443 * 444 * Note that we don't need to lock the socket, as the upper poll layers 445 * take care of normal races (between the test and the event) and we don't 446 * go look at any of the socket buffers directly. 447 */ 448 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 449 { 450 unsigned int mask; 451 struct sock *sk = sock->sk; 452 const struct tcp_sock *tp = tcp_sk(sk); 453 454 sock_rps_record_flow(sk); 455 456 sock_poll_wait(file, sk_sleep(sk), wait); 457 if (sk->sk_state == TCP_LISTEN) 458 return inet_csk_listen_poll(sk); 459 460 /* Socket is not locked. We are protected from async events 461 * by poll logic and correct handling of state changes 462 * made by other threads is impossible in any case. 463 */ 464 465 mask = 0; 466 467 /* 468 * POLLHUP is certainly not done right. But poll() doesn't 469 * have a notion of HUP in just one direction, and for a 470 * socket the read side is more interesting. 471 * 472 * Some poll() documentation says that POLLHUP is incompatible 473 * with the POLLOUT/POLLWR flags, so somebody should check this 474 * all. But careful, it tends to be safer to return too many 475 * bits than too few, and you can easily break real applications 476 * if you don't tell them that something has hung up! 477 * 478 * Check-me. 479 * 480 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 481 * our fs/select.c). It means that after we received EOF, 482 * poll always returns immediately, making impossible poll() on write() 483 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 484 * if and only if shutdown has been made in both directions. 485 * Actually, it is interesting to look how Solaris and DUX 486 * solve this dilemma. I would prefer, if POLLHUP were maskable, 487 * then we could set it on SND_SHUTDOWN. BTW examples given 488 * in Stevens' books assume exactly this behaviour, it explains 489 * why POLLHUP is incompatible with POLLOUT. --ANK 490 * 491 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 492 * blocking on fresh not-connected or disconnected socket. --ANK 493 */ 494 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 495 mask |= POLLHUP; 496 if (sk->sk_shutdown & RCV_SHUTDOWN) 497 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 498 499 /* Connected or passive Fast Open socket? */ 500 if (sk->sk_state != TCP_SYN_SENT && 501 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk)) { 502 int target = sock_rcvlowat(sk, 0, INT_MAX); 503 504 if (tp->urg_seq == tp->copied_seq && 505 !sock_flag(sk, SOCK_URGINLINE) && 506 tp->urg_data) 507 target++; 508 509 /* Potential race condition. If read of tp below will 510 * escape above sk->sk_state, we can be illegally awaken 511 * in SYN_* states. */ 512 if (tp->rcv_nxt - tp->copied_seq >= target) 513 mask |= POLLIN | POLLRDNORM; 514 515 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 516 if (sk_stream_is_writeable(sk)) { 517 mask |= POLLOUT | POLLWRNORM; 518 } else { /* send SIGIO later */ 519 set_bit(SOCK_ASYNC_NOSPACE, 520 &sk->sk_socket->flags); 521 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 522 523 /* Race breaker. If space is freed after 524 * wspace test but before the flags are set, 525 * IO signal will be lost. Memory barrier 526 * pairs with the input side. 527 */ 528 smp_mb__after_atomic(); 529 if (sk_stream_is_writeable(sk)) 530 mask |= POLLOUT | POLLWRNORM; 531 } 532 } else 533 mask |= POLLOUT | POLLWRNORM; 534 535 if (tp->urg_data & TCP_URG_VALID) 536 mask |= POLLPRI; 537 } 538 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 539 smp_rmb(); 540 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 541 mask |= POLLERR; 542 543 return mask; 544 } 545 EXPORT_SYMBOL(tcp_poll); 546 547 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 548 { 549 struct tcp_sock *tp = tcp_sk(sk); 550 int answ; 551 bool slow; 552 553 switch (cmd) { 554 case SIOCINQ: 555 if (sk->sk_state == TCP_LISTEN) 556 return -EINVAL; 557 558 slow = lock_sock_fast(sk); 559 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 560 answ = 0; 561 else if (sock_flag(sk, SOCK_URGINLINE) || 562 !tp->urg_data || 563 before(tp->urg_seq, tp->copied_seq) || 564 !before(tp->urg_seq, tp->rcv_nxt)) { 565 566 answ = tp->rcv_nxt - tp->copied_seq; 567 568 /* Subtract 1, if FIN was received */ 569 if (answ && sock_flag(sk, SOCK_DONE)) 570 answ--; 571 } else 572 answ = tp->urg_seq - tp->copied_seq; 573 unlock_sock_fast(sk, slow); 574 break; 575 case SIOCATMARK: 576 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 577 break; 578 case SIOCOUTQ: 579 if (sk->sk_state == TCP_LISTEN) 580 return -EINVAL; 581 582 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 583 answ = 0; 584 else 585 answ = tp->write_seq - tp->snd_una; 586 break; 587 case SIOCOUTQNSD: 588 if (sk->sk_state == TCP_LISTEN) 589 return -EINVAL; 590 591 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 592 answ = 0; 593 else 594 answ = tp->write_seq - tp->snd_nxt; 595 break; 596 default: 597 return -ENOIOCTLCMD; 598 } 599 600 return put_user(answ, (int __user *)arg); 601 } 602 EXPORT_SYMBOL(tcp_ioctl); 603 604 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 605 { 606 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH; 607 tp->pushed_seq = tp->write_seq; 608 } 609 610 static inline bool forced_push(const struct tcp_sock *tp) 611 { 612 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 613 } 614 615 static void skb_entail(struct sock *sk, struct sk_buff *skb) 616 { 617 struct tcp_sock *tp = tcp_sk(sk); 618 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 619 620 skb->csum = 0; 621 tcb->seq = tcb->end_seq = tp->write_seq; 622 tcb->tcp_flags = TCPHDR_ACK; 623 tcb->sacked = 0; 624 __skb_header_release(skb); 625 tcp_add_write_queue_tail(sk, skb); 626 sk->sk_wmem_queued += skb->truesize; 627 sk_mem_charge(sk, skb->truesize); 628 if (tp->nonagle & TCP_NAGLE_PUSH) 629 tp->nonagle &= ~TCP_NAGLE_PUSH; 630 } 631 632 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 633 { 634 if (flags & MSG_OOB) 635 tp->snd_up = tp->write_seq; 636 } 637 638 /* If a not yet filled skb is pushed, do not send it if 639 * we have data packets in Qdisc or NIC queues : 640 * Because TX completion will happen shortly, it gives a chance 641 * to coalesce future sendmsg() payload into this skb, without 642 * need for a timer, and with no latency trade off. 643 * As packets containing data payload have a bigger truesize 644 * than pure acks (dataless) packets, the last checks prevent 645 * autocorking if we only have an ACK in Qdisc/NIC queues, 646 * or if TX completion was delayed after we processed ACK packet. 647 */ 648 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb, 649 int size_goal) 650 { 651 return skb->len < size_goal && 652 sysctl_tcp_autocorking && 653 skb != tcp_write_queue_head(sk) && 654 atomic_read(&sk->sk_wmem_alloc) > skb->truesize; 655 } 656 657 static void tcp_push(struct sock *sk, int flags, int mss_now, 658 int nonagle, int size_goal) 659 { 660 struct tcp_sock *tp = tcp_sk(sk); 661 struct sk_buff *skb; 662 663 if (!tcp_send_head(sk)) 664 return; 665 666 skb = tcp_write_queue_tail(sk); 667 if (!(flags & MSG_MORE) || forced_push(tp)) 668 tcp_mark_push(tp, skb); 669 670 tcp_mark_urg(tp, flags); 671 672 if (tcp_should_autocork(sk, skb, size_goal)) { 673 674 /* avoid atomic op if TSQ_THROTTLED bit is already set */ 675 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) { 676 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); 677 set_bit(TSQ_THROTTLED, &tp->tsq_flags); 678 } 679 /* It is possible TX completion already happened 680 * before we set TSQ_THROTTLED. 681 */ 682 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize) 683 return; 684 } 685 686 if (flags & MSG_MORE) 687 nonagle = TCP_NAGLE_CORK; 688 689 __tcp_push_pending_frames(sk, mss_now, nonagle); 690 } 691 692 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 693 unsigned int offset, size_t len) 694 { 695 struct tcp_splice_state *tss = rd_desc->arg.data; 696 int ret; 697 698 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 699 tss->flags); 700 if (ret > 0) 701 rd_desc->count -= ret; 702 return ret; 703 } 704 705 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 706 { 707 /* Store TCP splice context information in read_descriptor_t. */ 708 read_descriptor_t rd_desc = { 709 .arg.data = tss, 710 .count = tss->len, 711 }; 712 713 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 714 } 715 716 /** 717 * tcp_splice_read - splice data from TCP socket to a pipe 718 * @sock: socket to splice from 719 * @ppos: position (not valid) 720 * @pipe: pipe to splice to 721 * @len: number of bytes to splice 722 * @flags: splice modifier flags 723 * 724 * Description: 725 * Will read pages from given socket and fill them into a pipe. 726 * 727 **/ 728 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 729 struct pipe_inode_info *pipe, size_t len, 730 unsigned int flags) 731 { 732 struct sock *sk = sock->sk; 733 struct tcp_splice_state tss = { 734 .pipe = pipe, 735 .len = len, 736 .flags = flags, 737 }; 738 long timeo; 739 ssize_t spliced; 740 int ret; 741 742 sock_rps_record_flow(sk); 743 /* 744 * We can't seek on a socket input 745 */ 746 if (unlikely(*ppos)) 747 return -ESPIPE; 748 749 ret = spliced = 0; 750 751 lock_sock(sk); 752 753 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 754 while (tss.len) { 755 ret = __tcp_splice_read(sk, &tss); 756 if (ret < 0) 757 break; 758 else if (!ret) { 759 if (spliced) 760 break; 761 if (sock_flag(sk, SOCK_DONE)) 762 break; 763 if (sk->sk_err) { 764 ret = sock_error(sk); 765 break; 766 } 767 if (sk->sk_shutdown & RCV_SHUTDOWN) 768 break; 769 if (sk->sk_state == TCP_CLOSE) { 770 /* 771 * This occurs when user tries to read 772 * from never connected socket. 773 */ 774 if (!sock_flag(sk, SOCK_DONE)) 775 ret = -ENOTCONN; 776 break; 777 } 778 if (!timeo) { 779 ret = -EAGAIN; 780 break; 781 } 782 sk_wait_data(sk, &timeo); 783 if (signal_pending(current)) { 784 ret = sock_intr_errno(timeo); 785 break; 786 } 787 continue; 788 } 789 tss.len -= ret; 790 spliced += ret; 791 792 if (!timeo) 793 break; 794 release_sock(sk); 795 lock_sock(sk); 796 797 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 798 (sk->sk_shutdown & RCV_SHUTDOWN) || 799 signal_pending(current)) 800 break; 801 } 802 803 release_sock(sk); 804 805 if (spliced) 806 return spliced; 807 808 return ret; 809 } 810 EXPORT_SYMBOL(tcp_splice_read); 811 812 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 813 { 814 struct sk_buff *skb; 815 816 /* The TCP header must be at least 32-bit aligned. */ 817 size = ALIGN(size, 4); 818 819 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 820 if (skb) { 821 if (sk_wmem_schedule(sk, skb->truesize)) { 822 skb_reserve(skb, sk->sk_prot->max_header); 823 /* 824 * Make sure that we have exactly size bytes 825 * available to the caller, no more, no less. 826 */ 827 skb->reserved_tailroom = skb->end - skb->tail - size; 828 return skb; 829 } 830 __kfree_skb(skb); 831 } else { 832 sk->sk_prot->enter_memory_pressure(sk); 833 sk_stream_moderate_sndbuf(sk); 834 } 835 return NULL; 836 } 837 838 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 839 int large_allowed) 840 { 841 struct tcp_sock *tp = tcp_sk(sk); 842 u32 new_size_goal, size_goal; 843 844 if (!large_allowed || !sk_can_gso(sk)) 845 return mss_now; 846 847 /* Note : tcp_tso_autosize() will eventually split this later */ 848 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER; 849 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal); 850 851 /* We try hard to avoid divides here */ 852 size_goal = tp->gso_segs * mss_now; 853 if (unlikely(new_size_goal < size_goal || 854 new_size_goal >= size_goal + mss_now)) { 855 tp->gso_segs = min_t(u16, new_size_goal / mss_now, 856 sk->sk_gso_max_segs); 857 size_goal = tp->gso_segs * mss_now; 858 } 859 860 return max(size_goal, mss_now); 861 } 862 863 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 864 { 865 int mss_now; 866 867 mss_now = tcp_current_mss(sk); 868 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 869 870 return mss_now; 871 } 872 873 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 874 size_t size, int flags) 875 { 876 struct tcp_sock *tp = tcp_sk(sk); 877 int mss_now, size_goal; 878 int err; 879 ssize_t copied; 880 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 881 882 /* Wait for a connection to finish. One exception is TCP Fast Open 883 * (passive side) where data is allowed to be sent before a connection 884 * is fully established. 885 */ 886 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 887 !tcp_passive_fastopen(sk)) { 888 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 889 goto out_err; 890 } 891 892 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 893 894 mss_now = tcp_send_mss(sk, &size_goal, flags); 895 copied = 0; 896 897 err = -EPIPE; 898 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 899 goto out_err; 900 901 while (size > 0) { 902 struct sk_buff *skb = tcp_write_queue_tail(sk); 903 int copy, i; 904 bool can_coalesce; 905 906 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 907 new_segment: 908 if (!sk_stream_memory_free(sk)) 909 goto wait_for_sndbuf; 910 911 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 912 if (!skb) 913 goto wait_for_memory; 914 915 skb_entail(sk, skb); 916 copy = size_goal; 917 } 918 919 if (copy > size) 920 copy = size; 921 922 i = skb_shinfo(skb)->nr_frags; 923 can_coalesce = skb_can_coalesce(skb, i, page, offset); 924 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 925 tcp_mark_push(tp, skb); 926 goto new_segment; 927 } 928 if (!sk_wmem_schedule(sk, copy)) 929 goto wait_for_memory; 930 931 if (can_coalesce) { 932 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 933 } else { 934 get_page(page); 935 skb_fill_page_desc(skb, i, page, offset, copy); 936 } 937 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 938 939 skb->len += copy; 940 skb->data_len += copy; 941 skb->truesize += copy; 942 sk->sk_wmem_queued += copy; 943 sk_mem_charge(sk, copy); 944 skb->ip_summed = CHECKSUM_PARTIAL; 945 tp->write_seq += copy; 946 TCP_SKB_CB(skb)->end_seq += copy; 947 tcp_skb_pcount_set(skb, 0); 948 949 if (!copied) 950 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 951 952 copied += copy; 953 offset += copy; 954 if (!(size -= copy)) { 955 tcp_tx_timestamp(sk, skb); 956 goto out; 957 } 958 959 if (skb->len < size_goal || (flags & MSG_OOB)) 960 continue; 961 962 if (forced_push(tp)) { 963 tcp_mark_push(tp, skb); 964 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 965 } else if (skb == tcp_send_head(sk)) 966 tcp_push_one(sk, mss_now); 967 continue; 968 969 wait_for_sndbuf: 970 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 971 wait_for_memory: 972 tcp_push(sk, flags & ~MSG_MORE, mss_now, 973 TCP_NAGLE_PUSH, size_goal); 974 975 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 976 goto do_error; 977 978 mss_now = tcp_send_mss(sk, &size_goal, flags); 979 } 980 981 out: 982 if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) 983 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 984 return copied; 985 986 do_error: 987 if (copied) 988 goto out; 989 out_err: 990 return sk_stream_error(sk, flags, err); 991 } 992 993 int tcp_sendpage(struct sock *sk, struct page *page, int offset, 994 size_t size, int flags) 995 { 996 ssize_t res; 997 998 if (!(sk->sk_route_caps & NETIF_F_SG) || 999 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 1000 return sock_no_sendpage(sk->sk_socket, page, offset, size, 1001 flags); 1002 1003 lock_sock(sk); 1004 res = do_tcp_sendpages(sk, page, offset, size, flags); 1005 release_sock(sk); 1006 return res; 1007 } 1008 EXPORT_SYMBOL(tcp_sendpage); 1009 1010 static inline int select_size(const struct sock *sk, bool sg) 1011 { 1012 const struct tcp_sock *tp = tcp_sk(sk); 1013 int tmp = tp->mss_cache; 1014 1015 if (sg) { 1016 if (sk_can_gso(sk)) { 1017 /* Small frames wont use a full page: 1018 * Payload will immediately follow tcp header. 1019 */ 1020 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER); 1021 } else { 1022 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 1023 1024 if (tmp >= pgbreak && 1025 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 1026 tmp = pgbreak; 1027 } 1028 } 1029 1030 return tmp; 1031 } 1032 1033 void tcp_free_fastopen_req(struct tcp_sock *tp) 1034 { 1035 if (tp->fastopen_req) { 1036 kfree(tp->fastopen_req); 1037 tp->fastopen_req = NULL; 1038 } 1039 } 1040 1041 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, 1042 int *copied, size_t size) 1043 { 1044 struct tcp_sock *tp = tcp_sk(sk); 1045 int err, flags; 1046 1047 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE)) 1048 return -EOPNOTSUPP; 1049 if (tp->fastopen_req) 1050 return -EALREADY; /* Another Fast Open is in progress */ 1051 1052 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request), 1053 sk->sk_allocation); 1054 if (unlikely(!tp->fastopen_req)) 1055 return -ENOBUFS; 1056 tp->fastopen_req->data = msg; 1057 tp->fastopen_req->size = size; 1058 1059 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; 1060 err = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1061 msg->msg_namelen, flags); 1062 *copied = tp->fastopen_req->copied; 1063 tcp_free_fastopen_req(tp); 1064 return err; 1065 } 1066 1067 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 1068 { 1069 struct tcp_sock *tp = tcp_sk(sk); 1070 struct sk_buff *skb; 1071 int flags, err, copied = 0; 1072 int mss_now = 0, size_goal, copied_syn = 0; 1073 bool sg; 1074 long timeo; 1075 1076 lock_sock(sk); 1077 1078 flags = msg->msg_flags; 1079 if (flags & MSG_FASTOPEN) { 1080 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size); 1081 if (err == -EINPROGRESS && copied_syn > 0) 1082 goto out; 1083 else if (err) 1084 goto out_err; 1085 } 1086 1087 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 1088 1089 /* Wait for a connection to finish. One exception is TCP Fast Open 1090 * (passive side) where data is allowed to be sent before a connection 1091 * is fully established. 1092 */ 1093 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 1094 !tcp_passive_fastopen(sk)) { 1095 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 1096 goto do_error; 1097 } 1098 1099 if (unlikely(tp->repair)) { 1100 if (tp->repair_queue == TCP_RECV_QUEUE) { 1101 copied = tcp_send_rcvq(sk, msg, size); 1102 goto out_nopush; 1103 } 1104 1105 err = -EINVAL; 1106 if (tp->repair_queue == TCP_NO_QUEUE) 1107 goto out_err; 1108 1109 /* 'common' sending to sendq */ 1110 } 1111 1112 /* This should be in poll */ 1113 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 1114 1115 mss_now = tcp_send_mss(sk, &size_goal, flags); 1116 1117 /* Ok commence sending. */ 1118 copied = 0; 1119 1120 err = -EPIPE; 1121 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 1122 goto out_err; 1123 1124 sg = !!(sk->sk_route_caps & NETIF_F_SG); 1125 1126 while (msg_data_left(msg)) { 1127 int copy = 0; 1128 int max = size_goal; 1129 1130 skb = tcp_write_queue_tail(sk); 1131 if (tcp_send_head(sk)) { 1132 if (skb->ip_summed == CHECKSUM_NONE) 1133 max = mss_now; 1134 copy = max - skb->len; 1135 } 1136 1137 if (copy <= 0) { 1138 new_segment: 1139 /* Allocate new segment. If the interface is SG, 1140 * allocate skb fitting to single page. 1141 */ 1142 if (!sk_stream_memory_free(sk)) 1143 goto wait_for_sndbuf; 1144 1145 skb = sk_stream_alloc_skb(sk, 1146 select_size(sk, sg), 1147 sk->sk_allocation); 1148 if (!skb) 1149 goto wait_for_memory; 1150 1151 /* 1152 * Check whether we can use HW checksum. 1153 */ 1154 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 1155 skb->ip_summed = CHECKSUM_PARTIAL; 1156 1157 skb_entail(sk, skb); 1158 copy = size_goal; 1159 max = size_goal; 1160 1161 /* All packets are restored as if they have 1162 * already been sent. skb_mstamp isn't set to 1163 * avoid wrong rtt estimation. 1164 */ 1165 if (tp->repair) 1166 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; 1167 } 1168 1169 /* Try to append data to the end of skb. */ 1170 if (copy > msg_data_left(msg)) 1171 copy = msg_data_left(msg); 1172 1173 /* Where to copy to? */ 1174 if (skb_availroom(skb) > 0) { 1175 /* We have some space in skb head. Superb! */ 1176 copy = min_t(int, copy, skb_availroom(skb)); 1177 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy); 1178 if (err) 1179 goto do_fault; 1180 } else { 1181 bool merge = true; 1182 int i = skb_shinfo(skb)->nr_frags; 1183 struct page_frag *pfrag = sk_page_frag(sk); 1184 1185 if (!sk_page_frag_refill(sk, pfrag)) 1186 goto wait_for_memory; 1187 1188 if (!skb_can_coalesce(skb, i, pfrag->page, 1189 pfrag->offset)) { 1190 if (i == MAX_SKB_FRAGS || !sg) { 1191 tcp_mark_push(tp, skb); 1192 goto new_segment; 1193 } 1194 merge = false; 1195 } 1196 1197 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1198 1199 if (!sk_wmem_schedule(sk, copy)) 1200 goto wait_for_memory; 1201 1202 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, 1203 pfrag->page, 1204 pfrag->offset, 1205 copy); 1206 if (err) 1207 goto do_error; 1208 1209 /* Update the skb. */ 1210 if (merge) { 1211 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1212 } else { 1213 skb_fill_page_desc(skb, i, pfrag->page, 1214 pfrag->offset, copy); 1215 get_page(pfrag->page); 1216 } 1217 pfrag->offset += copy; 1218 } 1219 1220 if (!copied) 1221 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1222 1223 tp->write_seq += copy; 1224 TCP_SKB_CB(skb)->end_seq += copy; 1225 tcp_skb_pcount_set(skb, 0); 1226 1227 copied += copy; 1228 if (!msg_data_left(msg)) { 1229 tcp_tx_timestamp(sk, skb); 1230 goto out; 1231 } 1232 1233 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) 1234 continue; 1235 1236 if (forced_push(tp)) { 1237 tcp_mark_push(tp, skb); 1238 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1239 } else if (skb == tcp_send_head(sk)) 1240 tcp_push_one(sk, mss_now); 1241 continue; 1242 1243 wait_for_sndbuf: 1244 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1245 wait_for_memory: 1246 if (copied) 1247 tcp_push(sk, flags & ~MSG_MORE, mss_now, 1248 TCP_NAGLE_PUSH, size_goal); 1249 1250 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1251 goto do_error; 1252 1253 mss_now = tcp_send_mss(sk, &size_goal, flags); 1254 } 1255 1256 out: 1257 if (copied) 1258 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); 1259 out_nopush: 1260 release_sock(sk); 1261 return copied + copied_syn; 1262 1263 do_fault: 1264 if (!skb->len) { 1265 tcp_unlink_write_queue(skb, sk); 1266 /* It is the one place in all of TCP, except connection 1267 * reset, where we can be unlinking the send_head. 1268 */ 1269 tcp_check_send_head(sk, skb); 1270 sk_wmem_free_skb(sk, skb); 1271 } 1272 1273 do_error: 1274 if (copied + copied_syn) 1275 goto out; 1276 out_err: 1277 err = sk_stream_error(sk, flags, err); 1278 release_sock(sk); 1279 return err; 1280 } 1281 EXPORT_SYMBOL(tcp_sendmsg); 1282 1283 /* 1284 * Handle reading urgent data. BSD has very simple semantics for 1285 * this, no blocking and very strange errors 8) 1286 */ 1287 1288 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1289 { 1290 struct tcp_sock *tp = tcp_sk(sk); 1291 1292 /* No URG data to read. */ 1293 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1294 tp->urg_data == TCP_URG_READ) 1295 return -EINVAL; /* Yes this is right ! */ 1296 1297 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1298 return -ENOTCONN; 1299 1300 if (tp->urg_data & TCP_URG_VALID) { 1301 int err = 0; 1302 char c = tp->urg_data; 1303 1304 if (!(flags & MSG_PEEK)) 1305 tp->urg_data = TCP_URG_READ; 1306 1307 /* Read urgent data. */ 1308 msg->msg_flags |= MSG_OOB; 1309 1310 if (len > 0) { 1311 if (!(flags & MSG_TRUNC)) 1312 err = memcpy_to_msg(msg, &c, 1); 1313 len = 1; 1314 } else 1315 msg->msg_flags |= MSG_TRUNC; 1316 1317 return err ? -EFAULT : len; 1318 } 1319 1320 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1321 return 0; 1322 1323 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1324 * the available implementations agree in this case: 1325 * this call should never block, independent of the 1326 * blocking state of the socket. 1327 * Mike <pall@rz.uni-karlsruhe.de> 1328 */ 1329 return -EAGAIN; 1330 } 1331 1332 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 1333 { 1334 struct sk_buff *skb; 1335 int copied = 0, err = 0; 1336 1337 /* XXX -- need to support SO_PEEK_OFF */ 1338 1339 skb_queue_walk(&sk->sk_write_queue, skb) { 1340 err = skb_copy_datagram_msg(skb, 0, msg, skb->len); 1341 if (err) 1342 break; 1343 1344 copied += skb->len; 1345 } 1346 1347 return err ?: copied; 1348 } 1349 1350 /* Clean up the receive buffer for full frames taken by the user, 1351 * then send an ACK if necessary. COPIED is the number of bytes 1352 * tcp_recvmsg has given to the user so far, it speeds up the 1353 * calculation of whether or not we must ACK for the sake of 1354 * a window update. 1355 */ 1356 static void tcp_cleanup_rbuf(struct sock *sk, int copied) 1357 { 1358 struct tcp_sock *tp = tcp_sk(sk); 1359 bool time_to_ack = false; 1360 1361 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1362 1363 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1364 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1365 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1366 1367 if (inet_csk_ack_scheduled(sk)) { 1368 const struct inet_connection_sock *icsk = inet_csk(sk); 1369 /* Delayed ACKs frequently hit locked sockets during bulk 1370 * receive. */ 1371 if (icsk->icsk_ack.blocked || 1372 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1373 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1374 /* 1375 * If this read emptied read buffer, we send ACK, if 1376 * connection is not bidirectional, user drained 1377 * receive buffer and there was a small segment 1378 * in queue. 1379 */ 1380 (copied > 0 && 1381 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1382 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1383 !icsk->icsk_ack.pingpong)) && 1384 !atomic_read(&sk->sk_rmem_alloc))) 1385 time_to_ack = true; 1386 } 1387 1388 /* We send an ACK if we can now advertise a non-zero window 1389 * which has been raised "significantly". 1390 * 1391 * Even if window raised up to infinity, do not send window open ACK 1392 * in states, where we will not receive more. It is useless. 1393 */ 1394 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1395 __u32 rcv_window_now = tcp_receive_window(tp); 1396 1397 /* Optimize, __tcp_select_window() is not cheap. */ 1398 if (2*rcv_window_now <= tp->window_clamp) { 1399 __u32 new_window = __tcp_select_window(sk); 1400 1401 /* Send ACK now, if this read freed lots of space 1402 * in our buffer. Certainly, new_window is new window. 1403 * We can advertise it now, if it is not less than current one. 1404 * "Lots" means "at least twice" here. 1405 */ 1406 if (new_window && new_window >= 2 * rcv_window_now) 1407 time_to_ack = true; 1408 } 1409 } 1410 if (time_to_ack) 1411 tcp_send_ack(sk); 1412 } 1413 1414 static void tcp_prequeue_process(struct sock *sk) 1415 { 1416 struct sk_buff *skb; 1417 struct tcp_sock *tp = tcp_sk(sk); 1418 1419 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1420 1421 /* RX process wants to run with disabled BHs, though it is not 1422 * necessary */ 1423 local_bh_disable(); 1424 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1425 sk_backlog_rcv(sk, skb); 1426 local_bh_enable(); 1427 1428 /* Clear memory counter. */ 1429 tp->ucopy.memory = 0; 1430 } 1431 1432 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1433 { 1434 struct sk_buff *skb; 1435 u32 offset; 1436 1437 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) { 1438 offset = seq - TCP_SKB_CB(skb)->seq; 1439 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1440 offset--; 1441 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) { 1442 *off = offset; 1443 return skb; 1444 } 1445 /* This looks weird, but this can happen if TCP collapsing 1446 * splitted a fat GRO packet, while we released socket lock 1447 * in skb_splice_bits() 1448 */ 1449 sk_eat_skb(sk, skb); 1450 } 1451 return NULL; 1452 } 1453 1454 /* 1455 * This routine provides an alternative to tcp_recvmsg() for routines 1456 * that would like to handle copying from skbuffs directly in 'sendfile' 1457 * fashion. 1458 * Note: 1459 * - It is assumed that the socket was locked by the caller. 1460 * - The routine does not block. 1461 * - At present, there is no support for reading OOB data 1462 * or for 'peeking' the socket using this routine 1463 * (although both would be easy to implement). 1464 */ 1465 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1466 sk_read_actor_t recv_actor) 1467 { 1468 struct sk_buff *skb; 1469 struct tcp_sock *tp = tcp_sk(sk); 1470 u32 seq = tp->copied_seq; 1471 u32 offset; 1472 int copied = 0; 1473 1474 if (sk->sk_state == TCP_LISTEN) 1475 return -ENOTCONN; 1476 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1477 if (offset < skb->len) { 1478 int used; 1479 size_t len; 1480 1481 len = skb->len - offset; 1482 /* Stop reading if we hit a patch of urgent data */ 1483 if (tp->urg_data) { 1484 u32 urg_offset = tp->urg_seq - seq; 1485 if (urg_offset < len) 1486 len = urg_offset; 1487 if (!len) 1488 break; 1489 } 1490 used = recv_actor(desc, skb, offset, len); 1491 if (used <= 0) { 1492 if (!copied) 1493 copied = used; 1494 break; 1495 } else if (used <= len) { 1496 seq += used; 1497 copied += used; 1498 offset += used; 1499 } 1500 /* If recv_actor drops the lock (e.g. TCP splice 1501 * receive) the skb pointer might be invalid when 1502 * getting here: tcp_collapse might have deleted it 1503 * while aggregating skbs from the socket queue. 1504 */ 1505 skb = tcp_recv_skb(sk, seq - 1, &offset); 1506 if (!skb) 1507 break; 1508 /* TCP coalescing might have appended data to the skb. 1509 * Try to splice more frags 1510 */ 1511 if (offset + 1 != skb->len) 1512 continue; 1513 } 1514 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { 1515 sk_eat_skb(sk, skb); 1516 ++seq; 1517 break; 1518 } 1519 sk_eat_skb(sk, skb); 1520 if (!desc->count) 1521 break; 1522 tp->copied_seq = seq; 1523 } 1524 tp->copied_seq = seq; 1525 1526 tcp_rcv_space_adjust(sk); 1527 1528 /* Clean up data we have read: This will do ACK frames. */ 1529 if (copied > 0) { 1530 tcp_recv_skb(sk, seq, &offset); 1531 tcp_cleanup_rbuf(sk, copied); 1532 } 1533 return copied; 1534 } 1535 EXPORT_SYMBOL(tcp_read_sock); 1536 1537 /* 1538 * This routine copies from a sock struct into the user buffer. 1539 * 1540 * Technical note: in 2.3 we work on _locked_ socket, so that 1541 * tricks with *seq access order and skb->users are not required. 1542 * Probably, code can be easily improved even more. 1543 */ 1544 1545 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 1546 int flags, int *addr_len) 1547 { 1548 struct tcp_sock *tp = tcp_sk(sk); 1549 int copied = 0; 1550 u32 peek_seq; 1551 u32 *seq; 1552 unsigned long used; 1553 int err; 1554 int target; /* Read at least this many bytes */ 1555 long timeo; 1556 struct task_struct *user_recv = NULL; 1557 struct sk_buff *skb; 1558 u32 urg_hole = 0; 1559 1560 if (unlikely(flags & MSG_ERRQUEUE)) 1561 return inet_recv_error(sk, msg, len, addr_len); 1562 1563 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) && 1564 (sk->sk_state == TCP_ESTABLISHED)) 1565 sk_busy_loop(sk, nonblock); 1566 1567 lock_sock(sk); 1568 1569 err = -ENOTCONN; 1570 if (sk->sk_state == TCP_LISTEN) 1571 goto out; 1572 1573 timeo = sock_rcvtimeo(sk, nonblock); 1574 1575 /* Urgent data needs to be handled specially. */ 1576 if (flags & MSG_OOB) 1577 goto recv_urg; 1578 1579 if (unlikely(tp->repair)) { 1580 err = -EPERM; 1581 if (!(flags & MSG_PEEK)) 1582 goto out; 1583 1584 if (tp->repair_queue == TCP_SEND_QUEUE) 1585 goto recv_sndq; 1586 1587 err = -EINVAL; 1588 if (tp->repair_queue == TCP_NO_QUEUE) 1589 goto out; 1590 1591 /* 'common' recv queue MSG_PEEK-ing */ 1592 } 1593 1594 seq = &tp->copied_seq; 1595 if (flags & MSG_PEEK) { 1596 peek_seq = tp->copied_seq; 1597 seq = &peek_seq; 1598 } 1599 1600 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1601 1602 do { 1603 u32 offset; 1604 1605 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1606 if (tp->urg_data && tp->urg_seq == *seq) { 1607 if (copied) 1608 break; 1609 if (signal_pending(current)) { 1610 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1611 break; 1612 } 1613 } 1614 1615 /* Next get a buffer. */ 1616 1617 skb_queue_walk(&sk->sk_receive_queue, skb) { 1618 /* Now that we have two receive queues this 1619 * shouldn't happen. 1620 */ 1621 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1622 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1623 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1624 flags)) 1625 break; 1626 1627 offset = *seq - TCP_SKB_CB(skb)->seq; 1628 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) 1629 offset--; 1630 if (offset < skb->len) 1631 goto found_ok_skb; 1632 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1633 goto found_fin_ok; 1634 WARN(!(flags & MSG_PEEK), 1635 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1636 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1637 } 1638 1639 /* Well, if we have backlog, try to process it now yet. */ 1640 1641 if (copied >= target && !sk->sk_backlog.tail) 1642 break; 1643 1644 if (copied) { 1645 if (sk->sk_err || 1646 sk->sk_state == TCP_CLOSE || 1647 (sk->sk_shutdown & RCV_SHUTDOWN) || 1648 !timeo || 1649 signal_pending(current)) 1650 break; 1651 } else { 1652 if (sock_flag(sk, SOCK_DONE)) 1653 break; 1654 1655 if (sk->sk_err) { 1656 copied = sock_error(sk); 1657 break; 1658 } 1659 1660 if (sk->sk_shutdown & RCV_SHUTDOWN) 1661 break; 1662 1663 if (sk->sk_state == TCP_CLOSE) { 1664 if (!sock_flag(sk, SOCK_DONE)) { 1665 /* This occurs when user tries to read 1666 * from never connected socket. 1667 */ 1668 copied = -ENOTCONN; 1669 break; 1670 } 1671 break; 1672 } 1673 1674 if (!timeo) { 1675 copied = -EAGAIN; 1676 break; 1677 } 1678 1679 if (signal_pending(current)) { 1680 copied = sock_intr_errno(timeo); 1681 break; 1682 } 1683 } 1684 1685 tcp_cleanup_rbuf(sk, copied); 1686 1687 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1688 /* Install new reader */ 1689 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1690 user_recv = current; 1691 tp->ucopy.task = user_recv; 1692 tp->ucopy.msg = msg; 1693 } 1694 1695 tp->ucopy.len = len; 1696 1697 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1698 !(flags & (MSG_PEEK | MSG_TRUNC))); 1699 1700 /* Ugly... If prequeue is not empty, we have to 1701 * process it before releasing socket, otherwise 1702 * order will be broken at second iteration. 1703 * More elegant solution is required!!! 1704 * 1705 * Look: we have the following (pseudo)queues: 1706 * 1707 * 1. packets in flight 1708 * 2. backlog 1709 * 3. prequeue 1710 * 4. receive_queue 1711 * 1712 * Each queue can be processed only if the next ones 1713 * are empty. At this point we have empty receive_queue. 1714 * But prequeue _can_ be not empty after 2nd iteration, 1715 * when we jumped to start of loop because backlog 1716 * processing added something to receive_queue. 1717 * We cannot release_sock(), because backlog contains 1718 * packets arrived _after_ prequeued ones. 1719 * 1720 * Shortly, algorithm is clear --- to process all 1721 * the queues in order. We could make it more directly, 1722 * requeueing packets from backlog to prequeue, if 1723 * is not empty. It is more elegant, but eats cycles, 1724 * unfortunately. 1725 */ 1726 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1727 goto do_prequeue; 1728 1729 /* __ Set realtime policy in scheduler __ */ 1730 } 1731 1732 if (copied >= target) { 1733 /* Do not sleep, just process backlog. */ 1734 release_sock(sk); 1735 lock_sock(sk); 1736 } else 1737 sk_wait_data(sk, &timeo); 1738 1739 if (user_recv) { 1740 int chunk; 1741 1742 /* __ Restore normal policy in scheduler __ */ 1743 1744 if ((chunk = len - tp->ucopy.len) != 0) { 1745 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1746 len -= chunk; 1747 copied += chunk; 1748 } 1749 1750 if (tp->rcv_nxt == tp->copied_seq && 1751 !skb_queue_empty(&tp->ucopy.prequeue)) { 1752 do_prequeue: 1753 tcp_prequeue_process(sk); 1754 1755 if ((chunk = len - tp->ucopy.len) != 0) { 1756 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1757 len -= chunk; 1758 copied += chunk; 1759 } 1760 } 1761 } 1762 if ((flags & MSG_PEEK) && 1763 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1764 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n", 1765 current->comm, 1766 task_pid_nr(current)); 1767 peek_seq = tp->copied_seq; 1768 } 1769 continue; 1770 1771 found_ok_skb: 1772 /* Ok so how much can we use? */ 1773 used = skb->len - offset; 1774 if (len < used) 1775 used = len; 1776 1777 /* Do we have urgent data here? */ 1778 if (tp->urg_data) { 1779 u32 urg_offset = tp->urg_seq - *seq; 1780 if (urg_offset < used) { 1781 if (!urg_offset) { 1782 if (!sock_flag(sk, SOCK_URGINLINE)) { 1783 ++*seq; 1784 urg_hole++; 1785 offset++; 1786 used--; 1787 if (!used) 1788 goto skip_copy; 1789 } 1790 } else 1791 used = urg_offset; 1792 } 1793 } 1794 1795 if (!(flags & MSG_TRUNC)) { 1796 err = skb_copy_datagram_msg(skb, offset, msg, used); 1797 if (err) { 1798 /* Exception. Bailout! */ 1799 if (!copied) 1800 copied = -EFAULT; 1801 break; 1802 } 1803 } 1804 1805 *seq += used; 1806 copied += used; 1807 len -= used; 1808 1809 tcp_rcv_space_adjust(sk); 1810 1811 skip_copy: 1812 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1813 tp->urg_data = 0; 1814 tcp_fast_path_check(sk); 1815 } 1816 if (used + offset < skb->len) 1817 continue; 1818 1819 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 1820 goto found_fin_ok; 1821 if (!(flags & MSG_PEEK)) 1822 sk_eat_skb(sk, skb); 1823 continue; 1824 1825 found_fin_ok: 1826 /* Process the FIN. */ 1827 ++*seq; 1828 if (!(flags & MSG_PEEK)) 1829 sk_eat_skb(sk, skb); 1830 break; 1831 } while (len > 0); 1832 1833 if (user_recv) { 1834 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1835 int chunk; 1836 1837 tp->ucopy.len = copied > 0 ? len : 0; 1838 1839 tcp_prequeue_process(sk); 1840 1841 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1842 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1843 len -= chunk; 1844 copied += chunk; 1845 } 1846 } 1847 1848 tp->ucopy.task = NULL; 1849 tp->ucopy.len = 0; 1850 } 1851 1852 /* According to UNIX98, msg_name/msg_namelen are ignored 1853 * on connected socket. I was just happy when found this 8) --ANK 1854 */ 1855 1856 /* Clean up data we have read: This will do ACK frames. */ 1857 tcp_cleanup_rbuf(sk, copied); 1858 1859 release_sock(sk); 1860 return copied; 1861 1862 out: 1863 release_sock(sk); 1864 return err; 1865 1866 recv_urg: 1867 err = tcp_recv_urg(sk, msg, len, flags); 1868 goto out; 1869 1870 recv_sndq: 1871 err = tcp_peek_sndq(sk, msg, len); 1872 goto out; 1873 } 1874 EXPORT_SYMBOL(tcp_recvmsg); 1875 1876 void tcp_set_state(struct sock *sk, int state) 1877 { 1878 int oldstate = sk->sk_state; 1879 1880 switch (state) { 1881 case TCP_ESTABLISHED: 1882 if (oldstate != TCP_ESTABLISHED) 1883 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1884 break; 1885 1886 case TCP_CLOSE: 1887 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1888 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1889 1890 sk->sk_prot->unhash(sk); 1891 if (inet_csk(sk)->icsk_bind_hash && 1892 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1893 inet_put_port(sk); 1894 /* fall through */ 1895 default: 1896 if (oldstate == TCP_ESTABLISHED) 1897 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1898 } 1899 1900 /* Change state AFTER socket is unhashed to avoid closed 1901 * socket sitting in hash tables. 1902 */ 1903 sk->sk_state = state; 1904 1905 #ifdef STATE_TRACE 1906 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1907 #endif 1908 } 1909 EXPORT_SYMBOL_GPL(tcp_set_state); 1910 1911 /* 1912 * State processing on a close. This implements the state shift for 1913 * sending our FIN frame. Note that we only send a FIN for some 1914 * states. A shutdown() may have already sent the FIN, or we may be 1915 * closed. 1916 */ 1917 1918 static const unsigned char new_state[16] = { 1919 /* current state: new state: action: */ 1920 [0 /* (Invalid) */] = TCP_CLOSE, 1921 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1922 [TCP_SYN_SENT] = TCP_CLOSE, 1923 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1924 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 1925 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 1926 [TCP_TIME_WAIT] = TCP_CLOSE, 1927 [TCP_CLOSE] = TCP_CLOSE, 1928 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 1929 [TCP_LAST_ACK] = TCP_LAST_ACK, 1930 [TCP_LISTEN] = TCP_CLOSE, 1931 [TCP_CLOSING] = TCP_CLOSING, 1932 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 1933 }; 1934 1935 static int tcp_close_state(struct sock *sk) 1936 { 1937 int next = (int)new_state[sk->sk_state]; 1938 int ns = next & TCP_STATE_MASK; 1939 1940 tcp_set_state(sk, ns); 1941 1942 return next & TCP_ACTION_FIN; 1943 } 1944 1945 /* 1946 * Shutdown the sending side of a connection. Much like close except 1947 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1948 */ 1949 1950 void tcp_shutdown(struct sock *sk, int how) 1951 { 1952 /* We need to grab some memory, and put together a FIN, 1953 * and then put it into the queue to be sent. 1954 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1955 */ 1956 if (!(how & SEND_SHUTDOWN)) 1957 return; 1958 1959 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1960 if ((1 << sk->sk_state) & 1961 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1962 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1963 /* Clear out any half completed packets. FIN if needed. */ 1964 if (tcp_close_state(sk)) 1965 tcp_send_fin(sk); 1966 } 1967 } 1968 EXPORT_SYMBOL(tcp_shutdown); 1969 1970 bool tcp_check_oom(struct sock *sk, int shift) 1971 { 1972 bool too_many_orphans, out_of_socket_memory; 1973 1974 too_many_orphans = tcp_too_many_orphans(sk, shift); 1975 out_of_socket_memory = tcp_out_of_memory(sk); 1976 1977 if (too_many_orphans) 1978 net_info_ratelimited("too many orphaned sockets\n"); 1979 if (out_of_socket_memory) 1980 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n"); 1981 return too_many_orphans || out_of_socket_memory; 1982 } 1983 1984 void tcp_close(struct sock *sk, long timeout) 1985 { 1986 struct sk_buff *skb; 1987 int data_was_unread = 0; 1988 int state; 1989 1990 lock_sock(sk); 1991 sk->sk_shutdown = SHUTDOWN_MASK; 1992 1993 if (sk->sk_state == TCP_LISTEN) { 1994 tcp_set_state(sk, TCP_CLOSE); 1995 1996 /* Special case. */ 1997 inet_csk_listen_stop(sk); 1998 1999 goto adjudge_to_death; 2000 } 2001 2002 /* We need to flush the recv. buffs. We do this only on the 2003 * descriptor close, not protocol-sourced closes, because the 2004 * reader process may not have drained the data yet! 2005 */ 2006 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 2007 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq; 2008 2009 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) 2010 len--; 2011 data_was_unread += len; 2012 __kfree_skb(skb); 2013 } 2014 2015 sk_mem_reclaim(sk); 2016 2017 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 2018 if (sk->sk_state == TCP_CLOSE) 2019 goto adjudge_to_death; 2020 2021 /* As outlined in RFC 2525, section 2.17, we send a RST here because 2022 * data was lost. To witness the awful effects of the old behavior of 2023 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 2024 * GET in an FTP client, suspend the process, wait for the client to 2025 * advertise a zero window, then kill -9 the FTP client, wheee... 2026 * Note: timeout is always zero in such a case. 2027 */ 2028 if (unlikely(tcp_sk(sk)->repair)) { 2029 sk->sk_prot->disconnect(sk, 0); 2030 } else if (data_was_unread) { 2031 /* Unread data was tossed, zap the connection. */ 2032 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 2033 tcp_set_state(sk, TCP_CLOSE); 2034 tcp_send_active_reset(sk, sk->sk_allocation); 2035 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 2036 /* Check zero linger _after_ checking for unread data. */ 2037 sk->sk_prot->disconnect(sk, 0); 2038 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 2039 } else if (tcp_close_state(sk)) { 2040 /* We FIN if the application ate all the data before 2041 * zapping the connection. 2042 */ 2043 2044 /* RED-PEN. Formally speaking, we have broken TCP state 2045 * machine. State transitions: 2046 * 2047 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 2048 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 2049 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 2050 * 2051 * are legal only when FIN has been sent (i.e. in window), 2052 * rather than queued out of window. Purists blame. 2053 * 2054 * F.e. "RFC state" is ESTABLISHED, 2055 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 2056 * 2057 * The visible declinations are that sometimes 2058 * we enter time-wait state, when it is not required really 2059 * (harmless), do not send active resets, when they are 2060 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 2061 * they look as CLOSING or LAST_ACK for Linux) 2062 * Probably, I missed some more holelets. 2063 * --ANK 2064 * XXX (TFO) - To start off we don't support SYN+ACK+FIN 2065 * in a single packet! (May consider it later but will 2066 * probably need API support or TCP_CORK SYN-ACK until 2067 * data is written and socket is closed.) 2068 */ 2069 tcp_send_fin(sk); 2070 } 2071 2072 sk_stream_wait_close(sk, timeout); 2073 2074 adjudge_to_death: 2075 state = sk->sk_state; 2076 sock_hold(sk); 2077 sock_orphan(sk); 2078 2079 /* It is the last release_sock in its life. It will remove backlog. */ 2080 release_sock(sk); 2081 2082 2083 /* Now socket is owned by kernel and we acquire BH lock 2084 to finish close. No need to check for user refs. 2085 */ 2086 local_bh_disable(); 2087 bh_lock_sock(sk); 2088 WARN_ON(sock_owned_by_user(sk)); 2089 2090 percpu_counter_inc(sk->sk_prot->orphan_count); 2091 2092 /* Have we already been destroyed by a softirq or backlog? */ 2093 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 2094 goto out; 2095 2096 /* This is a (useful) BSD violating of the RFC. There is a 2097 * problem with TCP as specified in that the other end could 2098 * keep a socket open forever with no application left this end. 2099 * We use a 1 minute timeout (about the same as BSD) then kill 2100 * our end. If they send after that then tough - BUT: long enough 2101 * that we won't make the old 4*rto = almost no time - whoops 2102 * reset mistake. 2103 * 2104 * Nope, it was not mistake. It is really desired behaviour 2105 * f.e. on http servers, when such sockets are useless, but 2106 * consume significant resources. Let's do it with special 2107 * linger2 option. --ANK 2108 */ 2109 2110 if (sk->sk_state == TCP_FIN_WAIT2) { 2111 struct tcp_sock *tp = tcp_sk(sk); 2112 if (tp->linger2 < 0) { 2113 tcp_set_state(sk, TCP_CLOSE); 2114 tcp_send_active_reset(sk, GFP_ATOMIC); 2115 NET_INC_STATS_BH(sock_net(sk), 2116 LINUX_MIB_TCPABORTONLINGER); 2117 } else { 2118 const int tmo = tcp_fin_time(sk); 2119 2120 if (tmo > TCP_TIMEWAIT_LEN) { 2121 inet_csk_reset_keepalive_timer(sk, 2122 tmo - TCP_TIMEWAIT_LEN); 2123 } else { 2124 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2125 goto out; 2126 } 2127 } 2128 } 2129 if (sk->sk_state != TCP_CLOSE) { 2130 sk_mem_reclaim(sk); 2131 if (tcp_check_oom(sk, 0)) { 2132 tcp_set_state(sk, TCP_CLOSE); 2133 tcp_send_active_reset(sk, GFP_ATOMIC); 2134 NET_INC_STATS_BH(sock_net(sk), 2135 LINUX_MIB_TCPABORTONMEMORY); 2136 } 2137 } 2138 2139 if (sk->sk_state == TCP_CLOSE) { 2140 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2141 /* We could get here with a non-NULL req if the socket is 2142 * aborted (e.g., closed with unread data) before 3WHS 2143 * finishes. 2144 */ 2145 if (req) 2146 reqsk_fastopen_remove(sk, req, false); 2147 inet_csk_destroy_sock(sk); 2148 } 2149 /* Otherwise, socket is reprieved until protocol close. */ 2150 2151 out: 2152 bh_unlock_sock(sk); 2153 local_bh_enable(); 2154 sock_put(sk); 2155 } 2156 EXPORT_SYMBOL(tcp_close); 2157 2158 /* These states need RST on ABORT according to RFC793 */ 2159 2160 static inline bool tcp_need_reset(int state) 2161 { 2162 return (1 << state) & 2163 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2164 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2165 } 2166 2167 int tcp_disconnect(struct sock *sk, int flags) 2168 { 2169 struct inet_sock *inet = inet_sk(sk); 2170 struct inet_connection_sock *icsk = inet_csk(sk); 2171 struct tcp_sock *tp = tcp_sk(sk); 2172 int err = 0; 2173 int old_state = sk->sk_state; 2174 2175 if (old_state != TCP_CLOSE) 2176 tcp_set_state(sk, TCP_CLOSE); 2177 2178 /* ABORT function of RFC793 */ 2179 if (old_state == TCP_LISTEN) { 2180 inet_csk_listen_stop(sk); 2181 } else if (unlikely(tp->repair)) { 2182 sk->sk_err = ECONNABORTED; 2183 } else if (tcp_need_reset(old_state) || 2184 (tp->snd_nxt != tp->write_seq && 2185 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2186 /* The last check adjusts for discrepancy of Linux wrt. RFC 2187 * states 2188 */ 2189 tcp_send_active_reset(sk, gfp_any()); 2190 sk->sk_err = ECONNRESET; 2191 } else if (old_state == TCP_SYN_SENT) 2192 sk->sk_err = ECONNRESET; 2193 2194 tcp_clear_xmit_timers(sk); 2195 __skb_queue_purge(&sk->sk_receive_queue); 2196 tcp_write_queue_purge(sk); 2197 __skb_queue_purge(&tp->out_of_order_queue); 2198 2199 inet->inet_dport = 0; 2200 2201 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2202 inet_reset_saddr(sk); 2203 2204 sk->sk_shutdown = 0; 2205 sock_reset_flag(sk, SOCK_DONE); 2206 tp->srtt_us = 0; 2207 if ((tp->write_seq += tp->max_window + 2) == 0) 2208 tp->write_seq = 1; 2209 icsk->icsk_backoff = 0; 2210 tp->snd_cwnd = 2; 2211 icsk->icsk_probes_out = 0; 2212 tp->packets_out = 0; 2213 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2214 tp->snd_cwnd_cnt = 0; 2215 tp->window_clamp = 0; 2216 tcp_set_ca_state(sk, TCP_CA_Open); 2217 tcp_clear_retrans(tp); 2218 inet_csk_delack_init(sk); 2219 tcp_init_send_head(sk); 2220 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2221 __sk_dst_reset(sk); 2222 2223 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2224 2225 sk->sk_error_report(sk); 2226 return err; 2227 } 2228 EXPORT_SYMBOL(tcp_disconnect); 2229 2230 void tcp_sock_destruct(struct sock *sk) 2231 { 2232 inet_sock_destruct(sk); 2233 2234 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq); 2235 } 2236 2237 static inline bool tcp_can_repair_sock(const struct sock *sk) 2238 { 2239 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) && 2240 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED)); 2241 } 2242 2243 static int tcp_repair_options_est(struct tcp_sock *tp, 2244 struct tcp_repair_opt __user *optbuf, unsigned int len) 2245 { 2246 struct tcp_repair_opt opt; 2247 2248 while (len >= sizeof(opt)) { 2249 if (copy_from_user(&opt, optbuf, sizeof(opt))) 2250 return -EFAULT; 2251 2252 optbuf++; 2253 len -= sizeof(opt); 2254 2255 switch (opt.opt_code) { 2256 case TCPOPT_MSS: 2257 tp->rx_opt.mss_clamp = opt.opt_val; 2258 break; 2259 case TCPOPT_WINDOW: 2260 { 2261 u16 snd_wscale = opt.opt_val & 0xFFFF; 2262 u16 rcv_wscale = opt.opt_val >> 16; 2263 2264 if (snd_wscale > 14 || rcv_wscale > 14) 2265 return -EFBIG; 2266 2267 tp->rx_opt.snd_wscale = snd_wscale; 2268 tp->rx_opt.rcv_wscale = rcv_wscale; 2269 tp->rx_opt.wscale_ok = 1; 2270 } 2271 break; 2272 case TCPOPT_SACK_PERM: 2273 if (opt.opt_val != 0) 2274 return -EINVAL; 2275 2276 tp->rx_opt.sack_ok |= TCP_SACK_SEEN; 2277 if (sysctl_tcp_fack) 2278 tcp_enable_fack(tp); 2279 break; 2280 case TCPOPT_TIMESTAMP: 2281 if (opt.opt_val != 0) 2282 return -EINVAL; 2283 2284 tp->rx_opt.tstamp_ok = 1; 2285 break; 2286 } 2287 } 2288 2289 return 0; 2290 } 2291 2292 /* 2293 * Socket option code for TCP. 2294 */ 2295 static int do_tcp_setsockopt(struct sock *sk, int level, 2296 int optname, char __user *optval, unsigned int optlen) 2297 { 2298 struct tcp_sock *tp = tcp_sk(sk); 2299 struct inet_connection_sock *icsk = inet_csk(sk); 2300 int val; 2301 int err = 0; 2302 2303 /* These are data/string values, all the others are ints */ 2304 switch (optname) { 2305 case TCP_CONGESTION: { 2306 char name[TCP_CA_NAME_MAX]; 2307 2308 if (optlen < 1) 2309 return -EINVAL; 2310 2311 val = strncpy_from_user(name, optval, 2312 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2313 if (val < 0) 2314 return -EFAULT; 2315 name[val] = 0; 2316 2317 lock_sock(sk); 2318 err = tcp_set_congestion_control(sk, name); 2319 release_sock(sk); 2320 return err; 2321 } 2322 default: 2323 /* fallthru */ 2324 break; 2325 } 2326 2327 if (optlen < sizeof(int)) 2328 return -EINVAL; 2329 2330 if (get_user(val, (int __user *)optval)) 2331 return -EFAULT; 2332 2333 lock_sock(sk); 2334 2335 switch (optname) { 2336 case TCP_MAXSEG: 2337 /* Values greater than interface MTU won't take effect. However 2338 * at the point when this call is done we typically don't yet 2339 * know which interface is going to be used */ 2340 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2341 err = -EINVAL; 2342 break; 2343 } 2344 tp->rx_opt.user_mss = val; 2345 break; 2346 2347 case TCP_NODELAY: 2348 if (val) { 2349 /* TCP_NODELAY is weaker than TCP_CORK, so that 2350 * this option on corked socket is remembered, but 2351 * it is not activated until cork is cleared. 2352 * 2353 * However, when TCP_NODELAY is set we make 2354 * an explicit push, which overrides even TCP_CORK 2355 * for currently queued segments. 2356 */ 2357 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2358 tcp_push_pending_frames(sk); 2359 } else { 2360 tp->nonagle &= ~TCP_NAGLE_OFF; 2361 } 2362 break; 2363 2364 case TCP_THIN_LINEAR_TIMEOUTS: 2365 if (val < 0 || val > 1) 2366 err = -EINVAL; 2367 else 2368 tp->thin_lto = val; 2369 break; 2370 2371 case TCP_THIN_DUPACK: 2372 if (val < 0 || val > 1) 2373 err = -EINVAL; 2374 else { 2375 tp->thin_dupack = val; 2376 if (tp->thin_dupack) 2377 tcp_disable_early_retrans(tp); 2378 } 2379 break; 2380 2381 case TCP_REPAIR: 2382 if (!tcp_can_repair_sock(sk)) 2383 err = -EPERM; 2384 else if (val == 1) { 2385 tp->repair = 1; 2386 sk->sk_reuse = SK_FORCE_REUSE; 2387 tp->repair_queue = TCP_NO_QUEUE; 2388 } else if (val == 0) { 2389 tp->repair = 0; 2390 sk->sk_reuse = SK_NO_REUSE; 2391 tcp_send_window_probe(sk); 2392 } else 2393 err = -EINVAL; 2394 2395 break; 2396 2397 case TCP_REPAIR_QUEUE: 2398 if (!tp->repair) 2399 err = -EPERM; 2400 else if (val < TCP_QUEUES_NR) 2401 tp->repair_queue = val; 2402 else 2403 err = -EINVAL; 2404 break; 2405 2406 case TCP_QUEUE_SEQ: 2407 if (sk->sk_state != TCP_CLOSE) 2408 err = -EPERM; 2409 else if (tp->repair_queue == TCP_SEND_QUEUE) 2410 tp->write_seq = val; 2411 else if (tp->repair_queue == TCP_RECV_QUEUE) 2412 tp->rcv_nxt = val; 2413 else 2414 err = -EINVAL; 2415 break; 2416 2417 case TCP_REPAIR_OPTIONS: 2418 if (!tp->repair) 2419 err = -EINVAL; 2420 else if (sk->sk_state == TCP_ESTABLISHED) 2421 err = tcp_repair_options_est(tp, 2422 (struct tcp_repair_opt __user *)optval, 2423 optlen); 2424 else 2425 err = -EPERM; 2426 break; 2427 2428 case TCP_CORK: 2429 /* When set indicates to always queue non-full frames. 2430 * Later the user clears this option and we transmit 2431 * any pending partial frames in the queue. This is 2432 * meant to be used alongside sendfile() to get properly 2433 * filled frames when the user (for example) must write 2434 * out headers with a write() call first and then use 2435 * sendfile to send out the data parts. 2436 * 2437 * TCP_CORK can be set together with TCP_NODELAY and it is 2438 * stronger than TCP_NODELAY. 2439 */ 2440 if (val) { 2441 tp->nonagle |= TCP_NAGLE_CORK; 2442 } else { 2443 tp->nonagle &= ~TCP_NAGLE_CORK; 2444 if (tp->nonagle&TCP_NAGLE_OFF) 2445 tp->nonagle |= TCP_NAGLE_PUSH; 2446 tcp_push_pending_frames(sk); 2447 } 2448 break; 2449 2450 case TCP_KEEPIDLE: 2451 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2452 err = -EINVAL; 2453 else { 2454 tp->keepalive_time = val * HZ; 2455 if (sock_flag(sk, SOCK_KEEPOPEN) && 2456 !((1 << sk->sk_state) & 2457 (TCPF_CLOSE | TCPF_LISTEN))) { 2458 u32 elapsed = keepalive_time_elapsed(tp); 2459 if (tp->keepalive_time > elapsed) 2460 elapsed = tp->keepalive_time - elapsed; 2461 else 2462 elapsed = 0; 2463 inet_csk_reset_keepalive_timer(sk, elapsed); 2464 } 2465 } 2466 break; 2467 case TCP_KEEPINTVL: 2468 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2469 err = -EINVAL; 2470 else 2471 tp->keepalive_intvl = val * HZ; 2472 break; 2473 case TCP_KEEPCNT: 2474 if (val < 1 || val > MAX_TCP_KEEPCNT) 2475 err = -EINVAL; 2476 else 2477 tp->keepalive_probes = val; 2478 break; 2479 case TCP_SYNCNT: 2480 if (val < 1 || val > MAX_TCP_SYNCNT) 2481 err = -EINVAL; 2482 else 2483 icsk->icsk_syn_retries = val; 2484 break; 2485 2486 case TCP_LINGER2: 2487 if (val < 0) 2488 tp->linger2 = -1; 2489 else if (val > sysctl_tcp_fin_timeout / HZ) 2490 tp->linger2 = 0; 2491 else 2492 tp->linger2 = val * HZ; 2493 break; 2494 2495 case TCP_DEFER_ACCEPT: 2496 /* Translate value in seconds to number of retransmits */ 2497 icsk->icsk_accept_queue.rskq_defer_accept = 2498 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2499 TCP_RTO_MAX / HZ); 2500 break; 2501 2502 case TCP_WINDOW_CLAMP: 2503 if (!val) { 2504 if (sk->sk_state != TCP_CLOSE) { 2505 err = -EINVAL; 2506 break; 2507 } 2508 tp->window_clamp = 0; 2509 } else 2510 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2511 SOCK_MIN_RCVBUF / 2 : val; 2512 break; 2513 2514 case TCP_QUICKACK: 2515 if (!val) { 2516 icsk->icsk_ack.pingpong = 1; 2517 } else { 2518 icsk->icsk_ack.pingpong = 0; 2519 if ((1 << sk->sk_state) & 2520 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2521 inet_csk_ack_scheduled(sk)) { 2522 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2523 tcp_cleanup_rbuf(sk, 1); 2524 if (!(val & 1)) 2525 icsk->icsk_ack.pingpong = 1; 2526 } 2527 } 2528 break; 2529 2530 #ifdef CONFIG_TCP_MD5SIG 2531 case TCP_MD5SIG: 2532 /* Read the IP->Key mappings from userspace */ 2533 err = tp->af_specific->md5_parse(sk, optval, optlen); 2534 break; 2535 #endif 2536 case TCP_USER_TIMEOUT: 2537 /* Cap the max time in ms TCP will retry or probe the window 2538 * before giving up and aborting (ETIMEDOUT) a connection. 2539 */ 2540 if (val < 0) 2541 err = -EINVAL; 2542 else 2543 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2544 break; 2545 2546 case TCP_FASTOPEN: 2547 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE | 2548 TCPF_LISTEN))) 2549 err = fastopen_init_queue(sk, val); 2550 else 2551 err = -EINVAL; 2552 break; 2553 case TCP_TIMESTAMP: 2554 if (!tp->repair) 2555 err = -EPERM; 2556 else 2557 tp->tsoffset = val - tcp_time_stamp; 2558 break; 2559 case TCP_NOTSENT_LOWAT: 2560 tp->notsent_lowat = val; 2561 sk->sk_write_space(sk); 2562 break; 2563 default: 2564 err = -ENOPROTOOPT; 2565 break; 2566 } 2567 2568 release_sock(sk); 2569 return err; 2570 } 2571 2572 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2573 unsigned int optlen) 2574 { 2575 const struct inet_connection_sock *icsk = inet_csk(sk); 2576 2577 if (level != SOL_TCP) 2578 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2579 optval, optlen); 2580 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2581 } 2582 EXPORT_SYMBOL(tcp_setsockopt); 2583 2584 #ifdef CONFIG_COMPAT 2585 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2586 char __user *optval, unsigned int optlen) 2587 { 2588 if (level != SOL_TCP) 2589 return inet_csk_compat_setsockopt(sk, level, optname, 2590 optval, optlen); 2591 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2592 } 2593 EXPORT_SYMBOL(compat_tcp_setsockopt); 2594 #endif 2595 2596 /* Return information about state of tcp endpoint in API format. */ 2597 void tcp_get_info(struct sock *sk, struct tcp_info *info) 2598 { 2599 const struct tcp_sock *tp = tcp_sk(sk); 2600 const struct inet_connection_sock *icsk = inet_csk(sk); 2601 u32 now = tcp_time_stamp; 2602 unsigned int start; 2603 u32 rate; 2604 2605 memset(info, 0, sizeof(*info)); 2606 2607 info->tcpi_state = sk->sk_state; 2608 info->tcpi_ca_state = icsk->icsk_ca_state; 2609 info->tcpi_retransmits = icsk->icsk_retransmits; 2610 info->tcpi_probes = icsk->icsk_probes_out; 2611 info->tcpi_backoff = icsk->icsk_backoff; 2612 2613 if (tp->rx_opt.tstamp_ok) 2614 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2615 if (tcp_is_sack(tp)) 2616 info->tcpi_options |= TCPI_OPT_SACK; 2617 if (tp->rx_opt.wscale_ok) { 2618 info->tcpi_options |= TCPI_OPT_WSCALE; 2619 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2620 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2621 } 2622 2623 if (tp->ecn_flags & TCP_ECN_OK) 2624 info->tcpi_options |= TCPI_OPT_ECN; 2625 if (tp->ecn_flags & TCP_ECN_SEEN) 2626 info->tcpi_options |= TCPI_OPT_ECN_SEEN; 2627 if (tp->syn_data_acked) 2628 info->tcpi_options |= TCPI_OPT_SYN_DATA; 2629 2630 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2631 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2632 info->tcpi_snd_mss = tp->mss_cache; 2633 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2634 2635 if (sk->sk_state == TCP_LISTEN) { 2636 info->tcpi_unacked = sk->sk_ack_backlog; 2637 info->tcpi_sacked = sk->sk_max_ack_backlog; 2638 } else { 2639 info->tcpi_unacked = tp->packets_out; 2640 info->tcpi_sacked = tp->sacked_out; 2641 } 2642 info->tcpi_lost = tp->lost_out; 2643 info->tcpi_retrans = tp->retrans_out; 2644 info->tcpi_fackets = tp->fackets_out; 2645 2646 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2647 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2648 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2649 2650 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2651 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2652 info->tcpi_rtt = tp->srtt_us >> 3; 2653 info->tcpi_rttvar = tp->mdev_us >> 2; 2654 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2655 info->tcpi_snd_cwnd = tp->snd_cwnd; 2656 info->tcpi_advmss = tp->advmss; 2657 info->tcpi_reordering = tp->reordering; 2658 2659 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2660 info->tcpi_rcv_space = tp->rcvq_space.space; 2661 2662 info->tcpi_total_retrans = tp->total_retrans; 2663 2664 rate = READ_ONCE(sk->sk_pacing_rate); 2665 info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL; 2666 2667 rate = READ_ONCE(sk->sk_max_pacing_rate); 2668 info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL; 2669 2670 do { 2671 start = u64_stats_fetch_begin_irq(&tp->syncp); 2672 info->tcpi_bytes_acked = tp->bytes_acked; 2673 info->tcpi_bytes_received = tp->bytes_received; 2674 } while (u64_stats_fetch_retry_irq(&tp->syncp, start)); 2675 } 2676 EXPORT_SYMBOL_GPL(tcp_get_info); 2677 2678 static int do_tcp_getsockopt(struct sock *sk, int level, 2679 int optname, char __user *optval, int __user *optlen) 2680 { 2681 struct inet_connection_sock *icsk = inet_csk(sk); 2682 struct tcp_sock *tp = tcp_sk(sk); 2683 int val, len; 2684 2685 if (get_user(len, optlen)) 2686 return -EFAULT; 2687 2688 len = min_t(unsigned int, len, sizeof(int)); 2689 2690 if (len < 0) 2691 return -EINVAL; 2692 2693 switch (optname) { 2694 case TCP_MAXSEG: 2695 val = tp->mss_cache; 2696 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2697 val = tp->rx_opt.user_mss; 2698 if (tp->repair) 2699 val = tp->rx_opt.mss_clamp; 2700 break; 2701 case TCP_NODELAY: 2702 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2703 break; 2704 case TCP_CORK: 2705 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2706 break; 2707 case TCP_KEEPIDLE: 2708 val = keepalive_time_when(tp) / HZ; 2709 break; 2710 case TCP_KEEPINTVL: 2711 val = keepalive_intvl_when(tp) / HZ; 2712 break; 2713 case TCP_KEEPCNT: 2714 val = keepalive_probes(tp); 2715 break; 2716 case TCP_SYNCNT: 2717 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2718 break; 2719 case TCP_LINGER2: 2720 val = tp->linger2; 2721 if (val >= 0) 2722 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2723 break; 2724 case TCP_DEFER_ACCEPT: 2725 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2726 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2727 break; 2728 case TCP_WINDOW_CLAMP: 2729 val = tp->window_clamp; 2730 break; 2731 case TCP_INFO: { 2732 struct tcp_info info; 2733 2734 if (get_user(len, optlen)) 2735 return -EFAULT; 2736 2737 tcp_get_info(sk, &info); 2738 2739 len = min_t(unsigned int, len, sizeof(info)); 2740 if (put_user(len, optlen)) 2741 return -EFAULT; 2742 if (copy_to_user(optval, &info, len)) 2743 return -EFAULT; 2744 return 0; 2745 } 2746 case TCP_CC_INFO: { 2747 const struct tcp_congestion_ops *ca_ops; 2748 union tcp_cc_info info; 2749 size_t sz = 0; 2750 int attr; 2751 2752 if (get_user(len, optlen)) 2753 return -EFAULT; 2754 2755 ca_ops = icsk->icsk_ca_ops; 2756 if (ca_ops && ca_ops->get_info) 2757 sz = ca_ops->get_info(sk, ~0U, &attr, &info); 2758 2759 len = min_t(unsigned int, len, sz); 2760 if (put_user(len, optlen)) 2761 return -EFAULT; 2762 if (copy_to_user(optval, &info, len)) 2763 return -EFAULT; 2764 return 0; 2765 } 2766 case TCP_QUICKACK: 2767 val = !icsk->icsk_ack.pingpong; 2768 break; 2769 2770 case TCP_CONGESTION: 2771 if (get_user(len, optlen)) 2772 return -EFAULT; 2773 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2774 if (put_user(len, optlen)) 2775 return -EFAULT; 2776 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2777 return -EFAULT; 2778 return 0; 2779 2780 case TCP_THIN_LINEAR_TIMEOUTS: 2781 val = tp->thin_lto; 2782 break; 2783 case TCP_THIN_DUPACK: 2784 val = tp->thin_dupack; 2785 break; 2786 2787 case TCP_REPAIR: 2788 val = tp->repair; 2789 break; 2790 2791 case TCP_REPAIR_QUEUE: 2792 if (tp->repair) 2793 val = tp->repair_queue; 2794 else 2795 return -EINVAL; 2796 break; 2797 2798 case TCP_QUEUE_SEQ: 2799 if (tp->repair_queue == TCP_SEND_QUEUE) 2800 val = tp->write_seq; 2801 else if (tp->repair_queue == TCP_RECV_QUEUE) 2802 val = tp->rcv_nxt; 2803 else 2804 return -EINVAL; 2805 break; 2806 2807 case TCP_USER_TIMEOUT: 2808 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2809 break; 2810 2811 case TCP_FASTOPEN: 2812 if (icsk->icsk_accept_queue.fastopenq) 2813 val = icsk->icsk_accept_queue.fastopenq->max_qlen; 2814 else 2815 val = 0; 2816 break; 2817 2818 case TCP_TIMESTAMP: 2819 val = tcp_time_stamp + tp->tsoffset; 2820 break; 2821 case TCP_NOTSENT_LOWAT: 2822 val = tp->notsent_lowat; 2823 break; 2824 default: 2825 return -ENOPROTOOPT; 2826 } 2827 2828 if (put_user(len, optlen)) 2829 return -EFAULT; 2830 if (copy_to_user(optval, &val, len)) 2831 return -EFAULT; 2832 return 0; 2833 } 2834 2835 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2836 int __user *optlen) 2837 { 2838 struct inet_connection_sock *icsk = inet_csk(sk); 2839 2840 if (level != SOL_TCP) 2841 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2842 optval, optlen); 2843 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2844 } 2845 EXPORT_SYMBOL(tcp_getsockopt); 2846 2847 #ifdef CONFIG_COMPAT 2848 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2849 char __user *optval, int __user *optlen) 2850 { 2851 if (level != SOL_TCP) 2852 return inet_csk_compat_getsockopt(sk, level, optname, 2853 optval, optlen); 2854 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2855 } 2856 EXPORT_SYMBOL(compat_tcp_getsockopt); 2857 #endif 2858 2859 #ifdef CONFIG_TCP_MD5SIG 2860 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool); 2861 static DEFINE_MUTEX(tcp_md5sig_mutex); 2862 static bool tcp_md5sig_pool_populated = false; 2863 2864 static void __tcp_alloc_md5sig_pool(void) 2865 { 2866 int cpu; 2867 2868 for_each_possible_cpu(cpu) { 2869 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) { 2870 struct crypto_hash *hash; 2871 2872 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2873 if (IS_ERR_OR_NULL(hash)) 2874 return; 2875 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash; 2876 } 2877 } 2878 /* before setting tcp_md5sig_pool_populated, we must commit all writes 2879 * to memory. See smp_rmb() in tcp_get_md5sig_pool() 2880 */ 2881 smp_wmb(); 2882 tcp_md5sig_pool_populated = true; 2883 } 2884 2885 bool tcp_alloc_md5sig_pool(void) 2886 { 2887 if (unlikely(!tcp_md5sig_pool_populated)) { 2888 mutex_lock(&tcp_md5sig_mutex); 2889 2890 if (!tcp_md5sig_pool_populated) 2891 __tcp_alloc_md5sig_pool(); 2892 2893 mutex_unlock(&tcp_md5sig_mutex); 2894 } 2895 return tcp_md5sig_pool_populated; 2896 } 2897 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2898 2899 2900 /** 2901 * tcp_get_md5sig_pool - get md5sig_pool for this user 2902 * 2903 * We use percpu structure, so if we succeed, we exit with preemption 2904 * and BH disabled, to make sure another thread or softirq handling 2905 * wont try to get same context. 2906 */ 2907 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 2908 { 2909 local_bh_disable(); 2910 2911 if (tcp_md5sig_pool_populated) { 2912 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */ 2913 smp_rmb(); 2914 return this_cpu_ptr(&tcp_md5sig_pool); 2915 } 2916 local_bh_enable(); 2917 return NULL; 2918 } 2919 EXPORT_SYMBOL(tcp_get_md5sig_pool); 2920 2921 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 2922 const struct tcphdr *th) 2923 { 2924 struct scatterlist sg; 2925 struct tcphdr hdr; 2926 int err; 2927 2928 /* We are not allowed to change tcphdr, make a local copy */ 2929 memcpy(&hdr, th, sizeof(hdr)); 2930 hdr.check = 0; 2931 2932 /* options aren't included in the hash */ 2933 sg_init_one(&sg, &hdr, sizeof(hdr)); 2934 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr)); 2935 return err; 2936 } 2937 EXPORT_SYMBOL(tcp_md5_hash_header); 2938 2939 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 2940 const struct sk_buff *skb, unsigned int header_len) 2941 { 2942 struct scatterlist sg; 2943 const struct tcphdr *tp = tcp_hdr(skb); 2944 struct hash_desc *desc = &hp->md5_desc; 2945 unsigned int i; 2946 const unsigned int head_data_len = skb_headlen(skb) > header_len ? 2947 skb_headlen(skb) - header_len : 0; 2948 const struct skb_shared_info *shi = skb_shinfo(skb); 2949 struct sk_buff *frag_iter; 2950 2951 sg_init_table(&sg, 1); 2952 2953 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 2954 if (crypto_hash_update(desc, &sg, head_data_len)) 2955 return 1; 2956 2957 for (i = 0; i < shi->nr_frags; ++i) { 2958 const struct skb_frag_struct *f = &shi->frags[i]; 2959 unsigned int offset = f->page_offset; 2960 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); 2961 2962 sg_set_page(&sg, page, skb_frag_size(f), 2963 offset_in_page(offset)); 2964 if (crypto_hash_update(desc, &sg, skb_frag_size(f))) 2965 return 1; 2966 } 2967 2968 skb_walk_frags(skb, frag_iter) 2969 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 2970 return 1; 2971 2972 return 0; 2973 } 2974 EXPORT_SYMBOL(tcp_md5_hash_skb_data); 2975 2976 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) 2977 { 2978 struct scatterlist sg; 2979 2980 sg_init_one(&sg, key->key, key->keylen); 2981 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 2982 } 2983 EXPORT_SYMBOL(tcp_md5_hash_key); 2984 2985 #endif 2986 2987 void tcp_done(struct sock *sk) 2988 { 2989 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2990 2991 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2992 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 2993 2994 tcp_set_state(sk, TCP_CLOSE); 2995 tcp_clear_xmit_timers(sk); 2996 if (req) 2997 reqsk_fastopen_remove(sk, req, false); 2998 2999 sk->sk_shutdown = SHUTDOWN_MASK; 3000 3001 if (!sock_flag(sk, SOCK_DEAD)) 3002 sk->sk_state_change(sk); 3003 else 3004 inet_csk_destroy_sock(sk); 3005 } 3006 EXPORT_SYMBOL_GPL(tcp_done); 3007 3008 extern struct tcp_congestion_ops tcp_reno; 3009 3010 static __initdata unsigned long thash_entries; 3011 static int __init set_thash_entries(char *str) 3012 { 3013 ssize_t ret; 3014 3015 if (!str) 3016 return 0; 3017 3018 ret = kstrtoul(str, 0, &thash_entries); 3019 if (ret) 3020 return 0; 3021 3022 return 1; 3023 } 3024 __setup("thash_entries=", set_thash_entries); 3025 3026 static void __init tcp_init_mem(void) 3027 { 3028 unsigned long limit = nr_free_buffer_pages() / 8; 3029 limit = max(limit, 128UL); 3030 sysctl_tcp_mem[0] = limit / 4 * 3; 3031 sysctl_tcp_mem[1] = limit; 3032 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 3033 } 3034 3035 void __init tcp_init(void) 3036 { 3037 unsigned long limit; 3038 int max_rshare, max_wshare, cnt; 3039 unsigned int i; 3040 3041 sock_skb_cb_check_size(sizeof(struct tcp_skb_cb)); 3042 3043 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL); 3044 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL); 3045 tcp_hashinfo.bind_bucket_cachep = 3046 kmem_cache_create("tcp_bind_bucket", 3047 sizeof(struct inet_bind_bucket), 0, 3048 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3049 3050 /* Size and allocate the main established and bind bucket 3051 * hash tables. 3052 * 3053 * The methodology is similar to that of the buffer cache. 3054 */ 3055 tcp_hashinfo.ehash = 3056 alloc_large_system_hash("TCP established", 3057 sizeof(struct inet_ehash_bucket), 3058 thash_entries, 3059 17, /* one slot per 128 KB of memory */ 3060 0, 3061 NULL, 3062 &tcp_hashinfo.ehash_mask, 3063 0, 3064 thash_entries ? 0 : 512 * 1024); 3065 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) 3066 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3067 3068 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3069 panic("TCP: failed to alloc ehash_locks"); 3070 tcp_hashinfo.bhash = 3071 alloc_large_system_hash("TCP bind", 3072 sizeof(struct inet_bind_hashbucket), 3073 tcp_hashinfo.ehash_mask + 1, 3074 17, /* one slot per 128 KB of memory */ 3075 0, 3076 &tcp_hashinfo.bhash_size, 3077 NULL, 3078 0, 3079 64 * 1024); 3080 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size; 3081 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3082 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3083 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3084 } 3085 3086 3087 cnt = tcp_hashinfo.ehash_mask + 1; 3088 3089 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3090 sysctl_tcp_max_orphans = cnt / 2; 3091 sysctl_max_syn_backlog = max(128, cnt / 256); 3092 3093 tcp_init_mem(); 3094 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3095 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7); 3096 max_wshare = min(4UL*1024*1024, limit); 3097 max_rshare = min(6UL*1024*1024, limit); 3098 3099 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3100 sysctl_tcp_wmem[1] = 16*1024; 3101 sysctl_tcp_wmem[2] = max(64*1024, max_wshare); 3102 3103 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3104 sysctl_tcp_rmem[1] = 87380; 3105 sysctl_tcp_rmem[2] = max(87380, max_rshare); 3106 3107 pr_info("Hash tables configured (established %u bind %u)\n", 3108 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3109 3110 tcp_metrics_init(); 3111 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0); 3112 tcp_tasklet_init(); 3113 } 3114