net/rxrpc/sendmsg.c

   1 /* AF_RXRPC sendmsg() implementation.
   2  *
   3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/net.h>
  15 #include <linux/gfp.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/export.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 enum rxrpc_command {
  23         RXRPC_CMD_SEND_DATA,            /* send data message */
  24         RXRPC_CMD_SEND_ABORT,           /* request abort generation */
  25         RXRPC_CMD_ACCEPT,               /* [server] accept incoming call */
  26         RXRPC_CMD_REJECT_BUSY,          /* [server] reject a call as busy */
  27 };
  28
  29 /*
  30  * wait for space to appear in the transmit/ACK window
  31  * - caller holds the socket locked
  32  */
  33 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
  34                                     struct rxrpc_call *call,
  35                                     long *timeo)
  36 {
  37         DECLARE_WAITQUEUE(myself, current);
  38         int ret;
  39
  40         _enter(",{%u,%u,%u}",
  41                call->tx_hard_ack, call->tx_top, call->tx_winsize);
  42
  43         add_wait_queue(&call->waitq, &myself);
  44
  45         for (;;) {
  46                 set_current_state(TASK_INTERRUPTIBLE);
  47                 ret = 0;
  48                 if (call->tx_top - call->tx_hard_ack <
  49                     min_t(unsigned int, call->tx_winsize,
  50                           call->cong_cwnd + call->cong_extra))
  51                         break;
  52                 if (call->state >= RXRPC_CALL_COMPLETE) {
  53                         ret = -call->error;
  54                         break;
  55                 }
  56                 if (signal_pending(current)) {
  57                         ret = sock_intr_errno(*timeo);
  58                         break;
  59                 }
  60
  61                 trace_rxrpc_transmit(call, rxrpc_transmit_wait);
  62                 release_sock(&rx->sk);
  63                 *timeo = schedule_timeout(*timeo);
  64                 lock_sock(&rx->sk);
  65         }
  66
  67         remove_wait_queue(&call->waitq, &myself);
  68         set_current_state(TASK_RUNNING);
  69         _leave(" = %d", ret);
  70         return ret;
  71 }
  72
  73 /*
  74  * Schedule an instant Tx resend.
  75  */
  76 static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
  77 {
  78         spin_lock_bh(&call->lock);
  79
  80         if (call->state < RXRPC_CALL_COMPLETE) {
  81                 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
  82                 if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
  83                         rxrpc_queue_call(call);
  84         }
  85
  86         spin_unlock_bh(&call->lock);
  87 }
  88
  89 /*
  90  * Queue a DATA packet for transmission, set the resend timeout and send the
  91  * packet immediately
  92  */
  93 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
  94                                bool last)
  95 {
  96         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  97         rxrpc_seq_t seq = sp->hdr.seq;
  98         int ret, ix;
  99         u8 annotation = RXRPC_TX_ANNO_UNACK;
 100
 101         _net("queue skb %p [%d]", skb, seq);
 102
 103         ASSERTCMP(seq, ==, call->tx_top + 1);
 104
 105         if (last)
 106                 annotation |= RXRPC_TX_ANNO_LAST;
 107
 108         /* We have to set the timestamp before queueing as the retransmit
 109          * algorithm can see the packet as soon as we queue it.
 110          */
 111         skb->tstamp = ktime_get_real();
 112
 113         ix = seq & RXRPC_RXTX_BUFF_MASK;
 114         rxrpc_get_skb(skb, rxrpc_skb_tx_got);
 115         call->rxtx_annotations[ix] = annotation;
 116         smp_wmb();
 117         call->rxtx_buffer[ix] = skb;
 118         call->tx_top = seq;
 119         if (last)
 120                 trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
 121         else
 122                 trace_rxrpc_transmit(call, rxrpc_transmit_queue);
 123
 124         if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
 125                 _debug("________awaiting reply/ACK__________");
 126                 write_lock_bh(&call->state_lock);
 127                 switch (call->state) {
 128                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 129                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 130                         break;
 131                 case RXRPC_CALL_SERVER_ACK_REQUEST:
 132                         call->state = RXRPC_CALL_SERVER_SEND_REPLY;
 133                         if (!last)
 134                                 break;
 135                 case RXRPC_CALL_SERVER_SEND_REPLY:
 136                         call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
 137                         break;
 138                 default:
 139                         break;
 140                 }
 141                 write_unlock_bh(&call->state_lock);
 142         }
 143
 144         if (seq == 1 && rxrpc_is_client_call(call))
 145                 rxrpc_expose_client_call(call);
 146
 147         ret = rxrpc_send_data_packet(call, skb, false);
 148         if (ret < 0) {
 149                 _debug("need instant resend %d", ret);
 150                 rxrpc_instant_resend(call, ix);
 151         } else {
 152                 ktime_t now = ktime_get_real(), resend_at;
 153
 154                 resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
 155
 156                 if (ktime_before(resend_at, call->resend_at)) {
 157                         call->resend_at = resend_at;
 158                         rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
 159                 }
 160         }
 161
 162         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 163         _leave("");
 164 }
 165
 166 /*
 167  * send data through a socket
 168  * - must be called in process context
 169  * - caller holds the socket locked
 170  */
 171 static int rxrpc_send_data(struct rxrpc_sock *rx,
 172                            struct rxrpc_call *call,
 173                            struct msghdr *msg, size_t len)
 174 {
 175         struct rxrpc_skb_priv *sp;
 176         struct sk_buff *skb;
 177         struct sock *sk = &rx->sk;
 178         long timeo;
 179         bool more;
 180         int ret, copied;
 181
 182         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 183
 184         /* this should be in poll */
 185         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 186
 187         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 188                 return -EPIPE;
 189
 190         more = msg->msg_flags & MSG_MORE;
 191
 192         skb = call->tx_pending;
 193         call->tx_pending = NULL;
 194         rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
 195
 196         copied = 0;
 197         do {
 198                 /* Check to see if there's a ping ACK to reply to. */
 199                 if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
 200                         rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
 201
 202                 if (!skb) {
 203                         size_t size, chunk, max, space;
 204
 205                         _debug("alloc");
 206
 207                         if (call->tx_top - call->tx_hard_ack >=
 208                             min_t(unsigned int, call->tx_winsize,
 209                                   call->cong_cwnd + call->cong_extra)) {
 210                                 ret = -EAGAIN;
 211                                 if (msg->msg_flags & MSG_DONTWAIT)
 212                                         goto maybe_error;
 213                                 ret = rxrpc_wait_for_tx_window(rx, call,
 214                                                                &timeo);
 215                                 if (ret < 0)
 216                                         goto maybe_error;
 217                         }
 218
 219                         max = RXRPC_JUMBO_DATALEN;
 220                         max -= call->conn->security_size;
 221                         max &= ~(call->conn->size_align - 1UL);
 222
 223                         chunk = max;
 224                         if (chunk > msg_data_left(msg) && !more)
 225                                 chunk = msg_data_left(msg);
 226
 227                         space = chunk + call->conn->size_align;
 228                         space &= ~(call->conn->size_align - 1UL);
 229
 230                         size = space + call->conn->security_size;
 231
 232                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
 233
 234                         /* create a buffer that we can retain until it's ACK'd */
 235                         skb = sock_alloc_send_skb(
 236                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
 237                         if (!skb)
 238                                 goto maybe_error;
 239
 240                         rxrpc_new_skb(skb, rxrpc_skb_tx_new);
 241
 242                         _debug("ALLOC SEND %p", skb);
 243
 244                         ASSERTCMP(skb->mark, ==, 0);
 245
 246                         _debug("HS: %u", call->conn->security_size);
 247                         skb_reserve(skb, call->conn->security_size);
 248                         skb->len += call->conn->security_size;
 249
 250                         sp = rxrpc_skb(skb);
 251                         sp->remain = chunk;
 252                         if (sp->remain > skb_tailroom(skb))
 253                                 sp->remain = skb_tailroom(skb);
 254
 255                         _net("skb: hr %d, tr %d, hl %d, rm %d",
 256                                skb_headroom(skb),
 257                                skb_tailroom(skb),
 258                                skb_headlen(skb),
 259                                sp->remain);
 260
 261                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 262                 }
 263
 264                 _debug("append");
 265                 sp = rxrpc_skb(skb);
 266
 267                 /* append next segment of data to the current buffer */
 268                 if (msg_data_left(msg) > 0) {
 269                         int copy = skb_tailroom(skb);
 270                         ASSERTCMP(copy, >, 0);
 271                         if (copy > msg_data_left(msg))
 272                                 copy = msg_data_left(msg);
 273                         if (copy > sp->remain)
 274                                 copy = sp->remain;
 275
 276                         _debug("add");
 277                         ret = skb_add_data(skb, &msg->msg_iter, copy);
 278                         _debug("added");
 279                         if (ret < 0)
 280                                 goto efault;
 281                         sp->remain -= copy;
 282                         skb->mark += copy;
 283                         copied += copy;
 284                 }
 285
 286                 /* check for the far side aborting the call or a network error
 287                  * occurring */
 288                 if (call->state == RXRPC_CALL_COMPLETE)
 289                         goto call_terminated;
 290
 291                 /* add the packet to the send queue if it's now full */
 292                 if (sp->remain <= 0 ||
 293                     (msg_data_left(msg) == 0 && !more)) {
 294                         struct rxrpc_connection *conn = call->conn;
 295                         uint32_t seq;
 296                         size_t pad;
 297
 298                         /* pad out if we're using security */
 299                         if (conn->security_ix) {
 300                                 pad = conn->security_size + skb->mark;
 301                                 pad = conn->size_align - pad;
 302                                 pad &= conn->size_align - 1;
 303                                 _debug("pad %zu", pad);
 304                                 if (pad)
 305                                         memset(skb_put(skb, pad), 0, pad);
 306                         }
 307
 308                         seq = call->tx_top + 1;
 309
 310                         sp->hdr.seq     = seq;
 311                         sp->hdr._rsvd   = 0;
 312                         sp->hdr.flags   = conn->out_clientflag;
 313
 314                         if (msg_data_left(msg) == 0 && !more)
 315                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
 316                         else if (call->tx_top - call->tx_hard_ack <
 317                                  call->tx_winsize)
 318                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
 319
 320                         ret = conn->security->secure_packet(
 321                                 call, skb, skb->mark, skb->head);
 322                         if (ret < 0)
 323                                 goto out;
 324
 325                         rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
 326                         skb = NULL;
 327                 }
 328         } while (msg_data_left(msg) > 0);
 329
 330 success:
 331         ret = copied;
 332 out:
 333         call->tx_pending = skb;
 334         _leave(" = %d", ret);
 335         return ret;
 336
 337 call_terminated:
 338         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 339         _leave(" = %d", -call->error);
 340         return -call->error;
 341
 342 maybe_error:
 343         if (copied)
 344                 goto success;
 345         goto out;
 346
 347 efault:
 348         ret = -EFAULT;
 349         goto out;
 350 }
 351
 352 /*
 353  * extract control messages from the sendmsg() control buffer
 354  */
 355 static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 356                               unsigned long *user_call_ID,
 357                               enum rxrpc_command *command,
 358                               u32 *abort_code,
 359                               bool *_exclusive)
 360 {
 361         struct cmsghdr *cmsg;
 362         bool got_user_ID = false;
 363         int len;
 364
 365         *command = RXRPC_CMD_SEND_DATA;
 366
 367         if (msg->msg_controllen == 0)
 368                 return -EINVAL;
 369
 370         for_each_cmsghdr(cmsg, msg) {
 371                 if (!CMSG_OK(msg, cmsg))
 372                         return -EINVAL;
 373
 374                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
 375                 _debug("CMSG %d, %d, %d",
 376                        cmsg->cmsg_level, cmsg->cmsg_type, len);
 377
 378                 if (cmsg->cmsg_level != SOL_RXRPC)
 379                         continue;
 380
 381                 switch (cmsg->cmsg_type) {
 382                 case RXRPC_USER_CALL_ID:
 383                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
 384                                 if (len != sizeof(u32))
 385                                         return -EINVAL;
 386                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
 387                         } else {
 388                                 if (len != sizeof(unsigned long))
 389                                         return -EINVAL;
 390                                 *user_call_ID = *(unsigned long *)
 391                                         CMSG_DATA(cmsg);
 392                         }
 393                         _debug("User Call ID %lx", *user_call_ID);
 394                         got_user_ID = true;
 395                         break;
 396
 397                 case RXRPC_ABORT:
 398                         if (*command != RXRPC_CMD_SEND_DATA)
 399                                 return -EINVAL;
 400                         *command = RXRPC_CMD_SEND_ABORT;
 401                         if (len != sizeof(*abort_code))
 402                                 return -EINVAL;
 403                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
 404                         _debug("Abort %x", *abort_code);
 405                         if (*abort_code == 0)
 406                                 return -EINVAL;
 407                         break;
 408
 409                 case RXRPC_ACCEPT:
 410                         if (*command != RXRPC_CMD_SEND_DATA)
 411                                 return -EINVAL;
 412                         *command = RXRPC_CMD_ACCEPT;
 413                         if (len != 0)
 414                                 return -EINVAL;
 415                         break;
 416
 417                 case RXRPC_EXCLUSIVE_CALL:
 418                         *_exclusive = true;
 419                         if (len != 0)
 420                                 return -EINVAL;
 421                         break;
 422                 default:
 423                         return -EINVAL;
 424                 }
 425         }
 426
 427         if (!got_user_ID)
 428                 return -EINVAL;
 429         _leave(" = 0");
 430         return 0;
 431 }
 432
 433 /*
 434  * Create a new client call for sendmsg().
 435  */
 436 static struct rxrpc_call *
 437 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 438                                   unsigned long user_call_ID, bool exclusive)
 439 {
 440         struct rxrpc_conn_parameters cp;
 441         struct rxrpc_call *call;
 442         struct key *key;
 443
 444         DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
 445
 446         _enter("");
 447
 448         if (!msg->msg_name)
 449                 return ERR_PTR(-EDESTADDRREQ);
 450
 451         key = rx->key;
 452         if (key && !rx->key->payload.data[0])
 453                 key = NULL;
 454
 455         memset(&cp, 0, sizeof(cp));
 456         cp.local                = rx->local;
 457         cp.key                  = rx->key;
 458         cp.security_level       = rx->min_sec_level;
 459         cp.exclusive            = rx->exclusive | exclusive;
 460         cp.service_id           = srx->srx_service;
 461         call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
 462
 463         _leave(" = %p\n", call);
 464         return call;
 465 }
 466
 467 /*
 468  * send a message forming part of a client call through an RxRPC socket
 469  * - caller holds the socket locked
 470  * - the socket may be either a client socket or a server socket
 471  */
 472 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 473 {
 474         enum rxrpc_command cmd;
 475         struct rxrpc_call *call;
 476         unsigned long user_call_ID = 0;
 477         bool exclusive = false;
 478         u32 abort_code = 0;
 479         int ret;
 480
 481         _enter("");
 482
 483         ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
 484                                  &exclusive);
 485         if (ret < 0)
 486                 return ret;
 487
 488         if (cmd == RXRPC_CMD_ACCEPT) {
 489                 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
 490                         return -EINVAL;
 491                 call = rxrpc_accept_call(rx, user_call_ID, NULL);
 492                 if (IS_ERR(call))
 493                         return PTR_ERR(call);
 494                 rxrpc_put_call(call, rxrpc_call_put);
 495                 return 0;
 496         }
 497
 498         call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
 499         if (!call) {
 500                 if (cmd != RXRPC_CMD_SEND_DATA)
 501                         return -EBADSLT;
 502                 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
 503                                                          exclusive);
 504                 if (IS_ERR(call))
 505                         return PTR_ERR(call);
 506         }
 507
 508         _debug("CALL %d USR %lx ST %d on CONN %p",
 509                call->debug_id, call->user_call_ID, call->state, call->conn);
 510
 511         if (call->state >= RXRPC_CALL_COMPLETE) {
 512                 /* it's too late for this call */
 513                 ret = -ESHUTDOWN;
 514         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
 515                 ret = 0;
 516                 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
 517                         ret = rxrpc_send_call_packet(call,
 518                                                      RXRPC_PACKET_TYPE_ABORT);
 519         } else if (cmd != RXRPC_CMD_SEND_DATA) {
 520                 ret = -EINVAL;
 521         } else if (rxrpc_is_client_call(call) &&
 522                    call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 523                 /* request phase complete for this client call */
 524                 ret = -EPROTO;
 525         } else if (rxrpc_is_service_call(call) &&
 526                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 527                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 528                 /* Reply phase not begun or not complete for service call. */
 529                 ret = -EPROTO;
 530         } else {
 531                 ret = rxrpc_send_data(rx, call, msg, len);
 532         }
 533
 534         rxrpc_put_call(call, rxrpc_call_put);
 535         _leave(" = %d", ret);
 536         return ret;
 537 }
 538
 539 /**
 540  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
 541  * @sock: The socket the call is on
 542  * @call: The call to send data through
 543  * @msg: The data to send
 544  * @len: The amount of data to send
 545  *
 546  * Allow a kernel service to send data on a call.  The call must be in an state
 547  * appropriate to sending data.  No control data should be supplied in @msg,
 548  * nor should an address be supplied.  MSG_MORE should be flagged if there's
 549  * more data to come, otherwise this data will end the transmission phase.
 550  */
 551 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 552                            struct msghdr *msg, size_t len)
 553 {
 554         int ret;
 555
 556         _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
 557
 558         ASSERTCMP(msg->msg_name, ==, NULL);
 559         ASSERTCMP(msg->msg_control, ==, NULL);
 560
 561         lock_sock(sock->sk);
 562
 563         _debug("CALL %d USR %lx ST %d on CONN %p",
 564                call->debug_id, call->user_call_ID, call->state, call->conn);
 565
 566         if (call->state >= RXRPC_CALL_COMPLETE) {
 567                 ret = -ESHUTDOWN; /* it's too late for this call */
 568         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 569                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 570                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 571                 ret = -EPROTO; /* request phase complete for this client call */
 572         } else {
 573                 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
 574         }
 575
 576         release_sock(sock->sk);
 577         _leave(" = %d", ret);
 578         return ret;
 579 }
 580 EXPORT_SYMBOL(rxrpc_kernel_send_data);
 581
 582 /**
 583  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
 584  * @sock: The socket the call is on
 585  * @call: The call to be aborted
 586  * @abort_code: The abort code to stick into the ABORT packet
 587  * @error: Local error value
 588  * @why: 3-char string indicating why.
 589  *
 590  * Allow a kernel service to abort a call, if it's still in an abortable state.
 591  */
 592 void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
 593                              u32 abort_code, int error, const char *why)
 594 {
 595         _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
 596
 597         lock_sock(sock->sk);
 598
 599         if (rxrpc_abort_call(why, call, 0, abort_code, error))
 600                 rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
 601
 602         release_sock(sock->sk);
 603         _leave("");
 604 }
 605
 606 EXPORT_SYMBOL(rxrpc_kernel_abort_call);