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                         call->ack_at = call->expire_at;
 134                         if (call->ackr_reason == RXRPC_ACK_DELAY)
 135                                 call->ackr_reason = 0;
 136                         __rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
 137                                           ktime_get_real());
 138                         if (!last)
 139                                 break;
 140                 case RXRPC_CALL_SERVER_SEND_REPLY:
 141                         call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
 142                         break;
 143                 default:
 144                         break;
 145                 }
 146                 write_unlock_bh(&call->state_lock);
 147         }
 148
 149         if (seq == 1 && rxrpc_is_client_call(call))
 150                 rxrpc_expose_client_call(call);
 151
 152         ret = rxrpc_send_data_packet(call, skb, false);
 153         if (ret < 0) {
 154                 _debug("need instant resend %d", ret);
 155                 rxrpc_instant_resend(call, ix);
 156         } else {
 157                 ktime_t now = ktime_get_real(), resend_at;
 158
 159                 resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
 160
 161                 if (ktime_before(resend_at, call->resend_at)) {
 162                         call->resend_at = resend_at;
 163                         rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
 164                 }
 165         }
 166
 167         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 168         _leave("");
 169 }
 170
 171 /*
 172  * send data through a socket
 173  * - must be called in process context
 174  * - caller holds the socket locked
 175  */
 176 static int rxrpc_send_data(struct rxrpc_sock *rx,
 177                            struct rxrpc_call *call,
 178                            struct msghdr *msg, size_t len)
 179 {
 180         struct rxrpc_skb_priv *sp;
 181         struct sk_buff *skb;
 182         struct sock *sk = &rx->sk;
 183         long timeo;
 184         bool more;
 185         int ret, copied;
 186
 187         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 188
 189         /* this should be in poll */
 190         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 191
 192         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 193                 return -EPIPE;
 194
 195         more = msg->msg_flags & MSG_MORE;
 196
 197         skb = call->tx_pending;
 198         call->tx_pending = NULL;
 199         rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
 200
 201         copied = 0;
 202         do {
 203                 /* Check to see if there's a ping ACK to reply to. */
 204                 if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
 205                         rxrpc_send_ack_packet(call, false);
 206
 207                 if (!skb) {
 208                         size_t size, chunk, max, space;
 209
 210                         _debug("alloc");
 211
 212                         if (call->tx_top - call->tx_hard_ack >=
 213                             min_t(unsigned int, call->tx_winsize,
 214                                   call->cong_cwnd + call->cong_extra)) {
 215                                 ret = -EAGAIN;
 216                                 if (msg->msg_flags & MSG_DONTWAIT)
 217                                         goto maybe_error;
 218                                 ret = rxrpc_wait_for_tx_window(rx, call,
 219                                                                &timeo);
 220                                 if (ret < 0)
 221                                         goto maybe_error;
 222                         }
 223
 224                         max = RXRPC_JUMBO_DATALEN;
 225                         max -= call->conn->security_size;
 226                         max &= ~(call->conn->size_align - 1UL);
 227
 228                         chunk = max;
 229                         if (chunk > msg_data_left(msg) && !more)
 230                                 chunk = msg_data_left(msg);
 231
 232                         space = chunk + call->conn->size_align;
 233                         space &= ~(call->conn->size_align - 1UL);
 234
 235                         size = space + call->conn->security_size;
 236
 237                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
 238
 239                         /* create a buffer that we can retain until it's ACK'd */
 240                         skb = sock_alloc_send_skb(
 241                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
 242                         if (!skb)
 243                                 goto maybe_error;
 244
 245                         rxrpc_new_skb(skb, rxrpc_skb_tx_new);
 246
 247                         _debug("ALLOC SEND %p", skb);
 248
 249                         ASSERTCMP(skb->mark, ==, 0);
 250
 251                         _debug("HS: %u", call->conn->security_size);
 252                         skb_reserve(skb, call->conn->security_size);
 253                         skb->len += call->conn->security_size;
 254
 255                         sp = rxrpc_skb(skb);
 256                         sp->remain = chunk;
 257                         if (sp->remain > skb_tailroom(skb))
 258                                 sp->remain = skb_tailroom(skb);
 259
 260                         _net("skb: hr %d, tr %d, hl %d, rm %d",
 261                                skb_headroom(skb),
 262                                skb_tailroom(skb),
 263                                skb_headlen(skb),
 264                                sp->remain);
 265
 266                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 267                 }
 268
 269                 _debug("append");
 270                 sp = rxrpc_skb(skb);
 271
 272                 /* append next segment of data to the current buffer */
 273                 if (msg_data_left(msg) > 0) {
 274                         int copy = skb_tailroom(skb);
 275                         ASSERTCMP(copy, >, 0);
 276                         if (copy > msg_data_left(msg))
 277                                 copy = msg_data_left(msg);
 278                         if (copy > sp->remain)
 279                                 copy = sp->remain;
 280
 281                         _debug("add");
 282                         ret = skb_add_data(skb, &msg->msg_iter, copy);
 283                         _debug("added");
 284                         if (ret < 0)
 285                                 goto efault;
 286                         sp->remain -= copy;
 287                         skb->mark += copy;
 288                         copied += copy;
 289                 }
 290
 291                 /* check for the far side aborting the call or a network error
 292                  * occurring */
 293                 if (call->state == RXRPC_CALL_COMPLETE)
 294                         goto call_terminated;
 295
 296                 /* add the packet to the send queue if it's now full */
 297                 if (sp->remain <= 0 ||
 298                     (msg_data_left(msg) == 0 && !more)) {
 299                         struct rxrpc_connection *conn = call->conn;
 300                         uint32_t seq;
 301                         size_t pad;
 302
 303                         /* pad out if we're using security */
 304                         if (conn->security_ix) {
 305                                 pad = conn->security_size + skb->mark;
 306                                 pad = conn->size_align - pad;
 307                                 pad &= conn->size_align - 1;
 308                                 _debug("pad %zu", pad);
 309                                 if (pad)
 310                                         memset(skb_put(skb, pad), 0, pad);
 311                         }
 312
 313                         seq = call->tx_top + 1;
 314
 315                         sp->hdr.seq     = seq;
 316                         sp->hdr._rsvd   = 0;
 317                         sp->hdr.flags   = conn->out_clientflag;
 318
 319                         if (msg_data_left(msg) == 0 && !more)
 320                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
 321                         else if (call->tx_top - call->tx_hard_ack <
 322                                  call->tx_winsize)
 323                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
 324
 325                         ret = conn->security->secure_packet(
 326                                 call, skb, skb->mark, skb->head);
 327                         if (ret < 0)
 328                                 goto out;
 329
 330                         rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
 331                         skb = NULL;
 332                 }
 333         } while (msg_data_left(msg) > 0);
 334
 335 success:
 336         ret = copied;
 337 out:
 338         call->tx_pending = skb;
 339         _leave(" = %d", ret);
 340         return ret;
 341
 342 call_terminated:
 343         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 344         _leave(" = %d", -call->error);
 345         return -call->error;
 346
 347 maybe_error:
 348         if (copied)
 349                 goto success;
 350         goto out;
 351
 352 efault:
 353         ret = -EFAULT;
 354         goto out;
 355 }
 356
 357 /*
 358  * extract control messages from the sendmsg() control buffer
 359  */
 360 static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 361                               unsigned long *user_call_ID,
 362                               enum rxrpc_command *command,
 363                               u32 *abort_code,
 364                               bool *_exclusive)
 365 {
 366         struct cmsghdr *cmsg;
 367         bool got_user_ID = false;
 368         int len;
 369
 370         *command = RXRPC_CMD_SEND_DATA;
 371
 372         if (msg->msg_controllen == 0)
 373                 return -EINVAL;
 374
 375         for_each_cmsghdr(cmsg, msg) {
 376                 if (!CMSG_OK(msg, cmsg))
 377                         return -EINVAL;
 378
 379                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
 380                 _debug("CMSG %d, %d, %d",
 381                        cmsg->cmsg_level, cmsg->cmsg_type, len);
 382
 383                 if (cmsg->cmsg_level != SOL_RXRPC)
 384                         continue;
 385
 386                 switch (cmsg->cmsg_type) {
 387                 case RXRPC_USER_CALL_ID:
 388                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
 389                                 if (len != sizeof(u32))
 390                                         return -EINVAL;
 391                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
 392                         } else {
 393                                 if (len != sizeof(unsigned long))
 394                                         return -EINVAL;
 395                                 *user_call_ID = *(unsigned long *)
 396                                         CMSG_DATA(cmsg);
 397                         }
 398                         _debug("User Call ID %lx", *user_call_ID);
 399                         got_user_ID = true;
 400                         break;
 401
 402                 case RXRPC_ABORT:
 403                         if (*command != RXRPC_CMD_SEND_DATA)
 404                                 return -EINVAL;
 405                         *command = RXRPC_CMD_SEND_ABORT;
 406                         if (len != sizeof(*abort_code))
 407                                 return -EINVAL;
 408                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
 409                         _debug("Abort %x", *abort_code);
 410                         if (*abort_code == 0)
 411                                 return -EINVAL;
 412                         break;
 413
 414                 case RXRPC_ACCEPT:
 415                         if (*command != RXRPC_CMD_SEND_DATA)
 416                                 return -EINVAL;
 417                         *command = RXRPC_CMD_ACCEPT;
 418                         if (len != 0)
 419                                 return -EINVAL;
 420                         break;
 421
 422                 case RXRPC_EXCLUSIVE_CALL:
 423                         *_exclusive = true;
 424                         if (len != 0)
 425                                 return -EINVAL;
 426                         break;
 427                 default:
 428                         return -EINVAL;
 429                 }
 430         }
 431
 432         if (!got_user_ID)
 433                 return -EINVAL;
 434         _leave(" = 0");
 435         return 0;
 436 }
 437
 438 /*
 439  * Create a new client call for sendmsg().
 440  */
 441 static struct rxrpc_call *
 442 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 443                                   unsigned long user_call_ID, bool exclusive)
 444 {
 445         struct rxrpc_conn_parameters cp;
 446         struct rxrpc_call *call;
 447         struct key *key;
 448
 449         DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
 450
 451         _enter("");
 452
 453         if (!msg->msg_name)
 454                 return ERR_PTR(-EDESTADDRREQ);
 455
 456         key = rx->key;
 457         if (key && !rx->key->payload.data[0])
 458                 key = NULL;
 459
 460         memset(&cp, 0, sizeof(cp));
 461         cp.local                = rx->local;
 462         cp.key                  = rx->key;
 463         cp.security_level       = rx->min_sec_level;
 464         cp.exclusive            = rx->exclusive | exclusive;
 465         cp.service_id           = srx->srx_service;
 466         call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
 467
 468         _leave(" = %p\n", call);
 469         return call;
 470 }
 471
 472 /*
 473  * send a message forming part of a client call through an RxRPC socket
 474  * - caller holds the socket locked
 475  * - the socket may be either a client socket or a server socket
 476  */
 477 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 478 {
 479         enum rxrpc_command cmd;
 480         struct rxrpc_call *call;
 481         unsigned long user_call_ID = 0;
 482         bool exclusive = false;
 483         u32 abort_code = 0;
 484         int ret;
 485
 486         _enter("");
 487
 488         ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
 489                                  &exclusive);
 490         if (ret < 0)
 491                 return ret;
 492
 493         if (cmd == RXRPC_CMD_ACCEPT) {
 494                 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
 495                         return -EINVAL;
 496                 call = rxrpc_accept_call(rx, user_call_ID, NULL);
 497                 if (IS_ERR(call))
 498                         return PTR_ERR(call);
 499                 rxrpc_put_call(call, rxrpc_call_put);
 500                 return 0;
 501         }
 502
 503         call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
 504         if (!call) {
 505                 if (cmd != RXRPC_CMD_SEND_DATA)
 506                         return -EBADSLT;
 507                 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
 508                                                          exclusive);
 509                 if (IS_ERR(call))
 510                         return PTR_ERR(call);
 511         }
 512
 513         _debug("CALL %d USR %lx ST %d on CONN %p",
 514                call->debug_id, call->user_call_ID, call->state, call->conn);
 515
 516         if (call->state >= RXRPC_CALL_COMPLETE) {
 517                 /* it's too late for this call */
 518                 ret = -ESHUTDOWN;
 519         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
 520                 ret = 0;
 521                 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
 522                         ret = rxrpc_send_abort_packet(call);
 523         } else if (cmd != RXRPC_CMD_SEND_DATA) {
 524                 ret = -EINVAL;
 525         } else if (rxrpc_is_client_call(call) &&
 526                    call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 527                 /* request phase complete for this client call */
 528                 ret = -EPROTO;
 529         } else if (rxrpc_is_service_call(call) &&
 530                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 531                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 532                 /* Reply phase not begun or not complete for service call. */
 533                 ret = -EPROTO;
 534         } else {
 535                 ret = rxrpc_send_data(rx, call, msg, len);
 536         }
 537
 538         rxrpc_put_call(call, rxrpc_call_put);
 539         _leave(" = %d", ret);
 540         return ret;
 541 }
 542
 543 /**
 544  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
 545  * @sock: The socket the call is on
 546  * @call: The call to send data through
 547  * @msg: The data to send
 548  * @len: The amount of data to send
 549  *
 550  * Allow a kernel service to send data on a call.  The call must be in an state
 551  * appropriate to sending data.  No control data should be supplied in @msg,
 552  * nor should an address be supplied.  MSG_MORE should be flagged if there's
 553  * more data to come, otherwise this data will end the transmission phase.
 554  */
 555 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 556                            struct msghdr *msg, size_t len)
 557 {
 558         int ret;
 559
 560         _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
 561
 562         ASSERTCMP(msg->msg_name, ==, NULL);
 563         ASSERTCMP(msg->msg_control, ==, NULL);
 564
 565         lock_sock(sock->sk);
 566
 567         _debug("CALL %d USR %lx ST %d on CONN %p",
 568                call->debug_id, call->user_call_ID, call->state, call->conn);
 569
 570         if (call->state >= RXRPC_CALL_COMPLETE) {
 571                 ret = -ESHUTDOWN; /* it's too late for this call */
 572         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 573                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 574                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 575                 ret = -EPROTO; /* request phase complete for this client call */
 576         } else {
 577                 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
 578         }
 579
 580         release_sock(sock->sk);
 581         _leave(" = %d", ret);
 582         return ret;
 583 }
 584 EXPORT_SYMBOL(rxrpc_kernel_send_data);
 585
 586 /**
 587  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
 588  * @sock: The socket the call is on
 589  * @call: The call to be aborted
 590  * @abort_code: The abort code to stick into the ABORT packet
 591  * @error: Local error value
 592  * @why: 3-char string indicating why.
 593  *
 594  * Allow a kernel service to abort a call, if it's still in an abortable state.
 595  */
 596 void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
 597                              u32 abort_code, int error, const char *why)
 598 {
 599         _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
 600
 601         lock_sock(sock->sk);
 602
 603         if (rxrpc_abort_call(why, call, 0, abort_code, error))
 604                 rxrpc_send_abort_packet(call);
 605
 606         release_sock(sock->sk);
 607         _leave("");
 608 }
 609
 610 EXPORT_SYMBOL(rxrpc_kernel_abort_call);