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