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