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] =
  82                         (call->rxtx_annotations[ix] & RXRPC_TX_ANNO_LAST) |
  83                         RXRPC_TX_ANNO_RETRANS;
  84                 if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
  85                         rxrpc_queue_call(call);
  86         }
  87
  88         spin_unlock_bh(&call->lock);
  89 }
  90
  91 /*
  92  * Queue a DATA packet for transmission, set the resend timeout and send the
  93  * packet immediately
  94  */
  95 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
  96                                bool last)
  97 {
  98         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  99         rxrpc_seq_t seq = sp->hdr.seq;
 100         int ret, ix;
 101         u8 annotation = RXRPC_TX_ANNO_UNACK;
 102
 103         _net("queue skb %p [%d]", skb, seq);
 104
 105         ASSERTCMP(seq, ==, call->tx_top + 1);
 106
 107         if (last)
 108                 annotation |= RXRPC_TX_ANNO_LAST;
 109
 110         /* We have to set the timestamp before queueing as the retransmit
 111          * algorithm can see the packet as soon as we queue it.
 112          */
 113         skb->tstamp = ktime_get_real();
 114
 115         ix = seq & RXRPC_RXTX_BUFF_MASK;
 116         rxrpc_get_skb(skb, rxrpc_skb_tx_got);
 117         call->rxtx_annotations[ix] = annotation;
 118         smp_wmb();
 119         call->rxtx_buffer[ix] = skb;
 120         call->tx_top = seq;
 121         if (last)
 122                 trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
 123         else
 124                 trace_rxrpc_transmit(call, rxrpc_transmit_queue);
 125
 126         if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
 127                 _debug("________awaiting reply/ACK__________");
 128                 write_lock_bh(&call->state_lock);
 129                 switch (call->state) {
 130                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 131                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 132                         break;
 133                 case RXRPC_CALL_SERVER_ACK_REQUEST:
 134                         call->state = RXRPC_CALL_SERVER_SEND_REPLY;
 135                         call->ack_at = call->expire_at;
 136                         if (call->ackr_reason == RXRPC_ACK_DELAY)
 137                                 call->ackr_reason = 0;
 138                         __rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
 139                                           ktime_get_real());
 140                         if (!last)
 141                                 break;
 142                 case RXRPC_CALL_SERVER_SEND_REPLY:
 143                         call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
 144                         break;
 145                 default:
 146                         break;
 147                 }
 148                 write_unlock_bh(&call->state_lock);
 149         }
 150
 151         if (seq == 1 && rxrpc_is_client_call(call))
 152                 rxrpc_expose_client_call(call);
 153
 154         ret = rxrpc_send_data_packet(call, skb, false);
 155         if (ret < 0) {
 156                 _debug("need instant resend %d", ret);
 157                 rxrpc_instant_resend(call, ix);
 158         } else {
 159                 ktime_t now = ktime_get_real(), resend_at;
 160
 161                 resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
 162
 163                 if (ktime_before(resend_at, call->resend_at)) {
 164                         call->resend_at = resend_at;
 165                         rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
 166                 }
 167         }
 168
 169         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 170         _leave("");
 171 }
 172
 173 /*
 174  * send data through a socket
 175  * - must be called in process context
 176  * - caller holds the socket locked
 177  */
 178 static int rxrpc_send_data(struct rxrpc_sock *rx,
 179                            struct rxrpc_call *call,
 180                            struct msghdr *msg, size_t len)
 181 {
 182         struct rxrpc_skb_priv *sp;
 183         struct sk_buff *skb;
 184         struct sock *sk = &rx->sk;
 185         long timeo;
 186         bool more;
 187         int ret, copied;
 188
 189         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 190
 191         /* this should be in poll */
 192         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 193
 194         if (sk->sk_shutdown & SEND_SHUTDOWN)
 195                 return -EPIPE;
 196
 197         more = msg->msg_flags & MSG_MORE;
 198
 199         skb = call->tx_pending;
 200         call->tx_pending = NULL;
 201         rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
 202
 203         copied = 0;
 204         do {
 205                 /* Check to see if there's a ping ACK to reply to. */
 206                 if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
 207                         rxrpc_send_ack_packet(call, false);
 208
 209                 if (!skb) {
 210                         size_t size, chunk, max, space;
 211
 212                         _debug("alloc");
 213
 214                         if (call->tx_top - call->tx_hard_ack >=
 215                             min_t(unsigned int, call->tx_winsize,
 216                                   call->cong_cwnd + call->cong_extra)) {
 217                                 ret = -EAGAIN;
 218                                 if (msg->msg_flags & MSG_DONTWAIT)
 219                                         goto maybe_error;
 220                                 ret = rxrpc_wait_for_tx_window(rx, call,
 221                                                                &timeo);
 222                                 if (ret < 0)
 223                                         goto maybe_error;
 224                         }
 225
 226                         max = RXRPC_JUMBO_DATALEN;
 227                         max -= call->conn->security_size;
 228                         max &= ~(call->conn->size_align - 1UL);
 229
 230                         chunk = max;
 231                         if (chunk > msg_data_left(msg) && !more)
 232                                 chunk = msg_data_left(msg);
 233
 234                         space = chunk + call->conn->size_align;
 235                         space &= ~(call->conn->size_align - 1UL);
 236
 237                         size = space + call->conn->security_size;
 238
 239                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
 240
 241                         /* create a buffer that we can retain until it's ACK'd */
 242                         skb = sock_alloc_send_skb(
 243                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
 244                         if (!skb)
 245                                 goto maybe_error;
 246
 247                         rxrpc_new_skb(skb, rxrpc_skb_tx_new);
 248
 249                         _debug("ALLOC SEND %p", skb);
 250
 251                         ASSERTCMP(skb->mark, ==, 0);
 252
 253                         _debug("HS: %u", call->conn->security_size);
 254                         skb_reserve(skb, call->conn->security_size);
 255                         skb->len += call->conn->security_size;
 256
 257                         sp = rxrpc_skb(skb);
 258                         sp->remain = chunk;
 259                         if (sp->remain > skb_tailroom(skb))
 260                                 sp->remain = skb_tailroom(skb);
 261
 262                         _net("skb: hr %d, tr %d, hl %d, rm %d",
 263                                skb_headroom(skb),
 264                                skb_tailroom(skb),
 265                                skb_headlen(skb),
 266                                sp->remain);
 267
 268                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 269                 }
 270
 271                 _debug("append");
 272                 sp = rxrpc_skb(skb);
 273
 274                 /* append next segment of data to the current buffer */
 275                 if (msg_data_left(msg) > 0) {
 276                         int copy = skb_tailroom(skb);
 277                         ASSERTCMP(copy, >, 0);
 278                         if (copy > msg_data_left(msg))
 279                                 copy = msg_data_left(msg);
 280                         if (copy > sp->remain)
 281                                 copy = sp->remain;
 282
 283                         _debug("add");
 284                         ret = skb_add_data(skb, &msg->msg_iter, copy);
 285                         _debug("added");
 286                         if (ret < 0)
 287                                 goto efault;
 288                         sp->remain -= copy;
 289                         skb->mark += copy;
 290                         copied += copy;
 291                 }
 292
 293                 /* check for the far side aborting the call or a network error
 294                  * occurring */
 295                 if (call->state == RXRPC_CALL_COMPLETE)
 296                         goto call_terminated;
 297
 298                 /* add the packet to the send queue if it's now full */
 299                 if (sp->remain <= 0 ||
 300                     (msg_data_left(msg) == 0 && !more)) {
 301                         struct rxrpc_connection *conn = call->conn;
 302                         uint32_t seq;
 303                         size_t pad;
 304
 305                         /* pad out if we're using security */
 306                         if (conn->security_ix) {
 307                                 pad = conn->security_size + skb->mark;
 308                                 pad = conn->size_align - pad;
 309                                 pad &= conn->size_align - 1;
 310                                 _debug("pad %zu", pad);
 311                                 if (pad)
 312                                         memset(skb_put(skb, pad), 0, pad);
 313                         }
 314
 315                         seq = call->tx_top + 1;
 316
 317                         sp->hdr.seq     = seq;
 318                         sp->hdr._rsvd   = 0;
 319                         sp->hdr.flags   = conn->out_clientflag;
 320
 321                         if (msg_data_left(msg) == 0 && !more)
 322                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
 323                         else if (call->tx_top - call->tx_hard_ack <
 324                                  call->tx_winsize)
 325                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
 326
 327                         ret = conn->security->secure_packet(
 328                                 call, skb, skb->mark, skb->head);
 329                         if (ret < 0)
 330                                 goto out;
 331
 332                         rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
 333                         skb = NULL;
 334                 }
 335         } while (msg_data_left(msg) > 0);
 336
 337 success:
 338         ret = copied;
 339         if (READ_ONCE(call->state) == RXRPC_CALL_COMPLETE) {
 340                 read_lock_bh(&call->state_lock);
 341                 if (call->error < 0)
 342                         ret = call->error;
 343                 read_unlock_bh(&call->state_lock);
 344         }
 345 out:
 346         call->tx_pending = skb;
 347         _leave(" = %d", ret);
 348         return ret;
 349
 350 call_terminated:
 351         rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 352         _leave(" = %d", -call->error);
 353         return -call->error;
 354
 355 maybe_error:
 356         if (copied)
 357                 goto success;
 358         goto out;
 359
 360 efault:
 361         ret = -EFAULT;
 362         goto out;
 363 }
 364
 365 /*
 366  * extract control messages from the sendmsg() control buffer
 367  */
 368 static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 369                               unsigned long *user_call_ID,
 370                               enum rxrpc_command *command,
 371                               u32 *abort_code,
 372                               bool *_exclusive)
 373 {
 374         struct cmsghdr *cmsg;
 375         bool got_user_ID = false;
 376         int len;
 377
 378         *command = RXRPC_CMD_SEND_DATA;
 379
 380         if (msg->msg_controllen == 0)
 381                 return -EINVAL;
 382
 383         for_each_cmsghdr(cmsg, msg) {
 384                 if (!CMSG_OK(msg, cmsg))
 385                         return -EINVAL;
 386
 387                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
 388                 _debug("CMSG %d, %d, %d",
 389                        cmsg->cmsg_level, cmsg->cmsg_type, len);
 390
 391                 if (cmsg->cmsg_level != SOL_RXRPC)
 392                         continue;
 393
 394                 switch (cmsg->cmsg_type) {
 395                 case RXRPC_USER_CALL_ID:
 396                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
 397                                 if (len != sizeof(u32))
 398                                         return -EINVAL;
 399                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
 400                         } else {
 401                                 if (len != sizeof(unsigned long))
 402                                         return -EINVAL;
 403                                 *user_call_ID = *(unsigned long *)
 404                                         CMSG_DATA(cmsg);
 405                         }
 406                         _debug("User Call ID %lx", *user_call_ID);
 407                         got_user_ID = true;
 408                         break;
 409
 410                 case RXRPC_ABORT:
 411                         if (*command != RXRPC_CMD_SEND_DATA)
 412                                 return -EINVAL;
 413                         *command = RXRPC_CMD_SEND_ABORT;
 414                         if (len != sizeof(*abort_code))
 415                                 return -EINVAL;
 416                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
 417                         _debug("Abort %x", *abort_code);
 418                         if (*abort_code == 0)
 419                                 return -EINVAL;
 420                         break;
 421
 422                 case RXRPC_ACCEPT:
 423                         if (*command != RXRPC_CMD_SEND_DATA)
 424                                 return -EINVAL;
 425                         *command = RXRPC_CMD_ACCEPT;
 426                         if (len != 0)
 427                                 return -EINVAL;
 428                         break;
 429
 430                 case RXRPC_EXCLUSIVE_CALL:
 431                         *_exclusive = true;
 432                         if (len != 0)
 433                                 return -EINVAL;
 434                         break;
 435                 default:
 436                         return -EINVAL;
 437                 }
 438         }
 439
 440         if (!got_user_ID)
 441                 return -EINVAL;
 442         _leave(" = 0");
 443         return 0;
 444 }
 445
 446 /*
 447  * Create a new client call for sendmsg().
 448  */
 449 static struct rxrpc_call *
 450 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 451                                   unsigned long user_call_ID, bool exclusive)
 452 {
 453         struct rxrpc_conn_parameters cp;
 454         struct rxrpc_call *call;
 455         struct key *key;
 456
 457         DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
 458
 459         _enter("");
 460
 461         if (!msg->msg_name)
 462                 return ERR_PTR(-EDESTADDRREQ);
 463
 464         key = rx->key;
 465         if (key && !rx->key->payload.data[0])
 466                 key = NULL;
 467
 468         memset(&cp, 0, sizeof(cp));
 469         cp.local                = rx->local;
 470         cp.key                  = rx->key;
 471         cp.security_level       = rx->min_sec_level;
 472         cp.exclusive            = rx->exclusive | exclusive;
 473         cp.service_id           = srx->srx_service;
 474         call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
 475
 476         _leave(" = %p\n", call);
 477         return call;
 478 }
 479
 480 /*
 481  * send a message forming part of a client call through an RxRPC socket
 482  * - caller holds the socket locked
 483  * - the socket may be either a client socket or a server socket
 484  */
 485 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 486 {
 487         enum rxrpc_command cmd;
 488         struct rxrpc_call *call;
 489         unsigned long user_call_ID = 0;
 490         bool exclusive = false;
 491         u32 abort_code = 0;
 492         int ret;
 493
 494         _enter("");
 495
 496         ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
 497                                  &exclusive);
 498         if (ret < 0)
 499                 return ret;
 500
 501         if (cmd == RXRPC_CMD_ACCEPT) {
 502                 if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
 503                         return -EINVAL;
 504                 call = rxrpc_accept_call(rx, user_call_ID, NULL);
 505                 if (IS_ERR(call))
 506                         return PTR_ERR(call);
 507                 rxrpc_put_call(call, rxrpc_call_put);
 508                 return 0;
 509         }
 510
 511         call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
 512         if (!call) {
 513                 if (cmd != RXRPC_CMD_SEND_DATA)
 514                         return -EBADSLT;
 515                 call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
 516                                                          exclusive);
 517                 if (IS_ERR(call))
 518                         return PTR_ERR(call);
 519         }
 520
 521         _debug("CALL %d USR %lx ST %d on CONN %p",
 522                call->debug_id, call->user_call_ID, call->state, call->conn);
 523
 524         if (call->state >= RXRPC_CALL_COMPLETE) {
 525                 /* it's too late for this call */
 526                 ret = -ESHUTDOWN;
 527         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
 528                 ret = 0;
 529                 if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
 530                         ret = rxrpc_send_abort_packet(call);
 531         } else if (cmd != RXRPC_CMD_SEND_DATA) {
 532                 ret = -EINVAL;
 533         } else if (rxrpc_is_client_call(call) &&
 534                    call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 535                 /* request phase complete for this client call */
 536                 ret = -EPROTO;
 537         } else if (rxrpc_is_service_call(call) &&
 538                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 539                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 540                 /* Reply phase not begun or not complete for service call. */
 541                 ret = -EPROTO;
 542         } else {
 543                 ret = rxrpc_send_data(rx, call, msg, len);
 544         }
 545
 546         rxrpc_put_call(call, rxrpc_call_put);
 547         _leave(" = %d", ret);
 548         return ret;
 549 }
 550
 551 /**
 552  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
 553  * @sock: The socket the call is on
 554  * @call: The call to send data through
 555  * @msg: The data to send
 556  * @len: The amount of data to send
 557  *
 558  * Allow a kernel service to send data on a call.  The call must be in an state
 559  * appropriate to sending data.  No control data should be supplied in @msg,
 560  * nor should an address be supplied.  MSG_MORE should be flagged if there's
 561  * more data to come, otherwise this data will end the transmission phase.
 562  */
 563 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 564                            struct msghdr *msg, size_t len)
 565 {
 566         int ret;
 567
 568         _enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
 569
 570         ASSERTCMP(msg->msg_name, ==, NULL);
 571         ASSERTCMP(msg->msg_control, ==, NULL);
 572
 573         lock_sock(sock->sk);
 574
 575         _debug("CALL %d USR %lx ST %d on CONN %p",
 576                call->debug_id, call->user_call_ID, call->state, call->conn);
 577
 578         if (call->state >= RXRPC_CALL_COMPLETE) {
 579                 ret = -ESHUTDOWN; /* it's too late for this call */
 580         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 581                    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 582                    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 583                 ret = -EPROTO; /* request phase complete for this client call */
 584         } else {
 585                 ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
 586         }
 587
 588         release_sock(sock->sk);
 589         _leave(" = %d", ret);
 590         return ret;
 591 }
 592 EXPORT_SYMBOL(rxrpc_kernel_send_data);
 593
 594 /**
 595  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
 596  * @sock: The socket the call is on
 597  * @call: The call to be aborted
 598  * @abort_code: The abort code to stick into the ABORT packet
 599  * @error: Local error value
 600  * @why: 3-char string indicating why.
 601  *
 602  * Allow a kernel service to abort a call, if it's still in an abortable state.
 603  */
 604 void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
 605                              u32 abort_code, int error, const char *why)
 606 {
 607         _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
 608
 609         lock_sock(sock->sk);
 610
 611         if (rxrpc_abort_call(why, call, 0, abort_code, error))
 612                 rxrpc_send_abort_packet(call);
 613
 614         release_sock(sock->sk);
 615         _leave("");
 616 }
 617
 618 EXPORT_SYMBOL(rxrpc_kernel_abort_call);