net/rxrpc/recvmsg.c

   1 /* RxRPC recvmsg() implementation
   2  *
   3  * Copyright (C) 2007 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 License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, 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/skbuff.h>
  16 #include <linux/export.h>
  17 #include <net/sock.h>
  18 #include <net/af_rxrpc.h>
  19 #include "ar-internal.h"
  20
  21 /*
  22  * Post a call for attention by the socket or kernel service.  Further
  23  * notifications are suppressed by putting recvmsg_link on a dummy queue.
  24  */
  25 void rxrpc_notify_socket(struct rxrpc_call *call)
  26 {
  27         struct rxrpc_sock *rx;
  28         struct sock *sk;
  29
  30         _enter("%d", call->debug_id);
  31
  32         if (!list_empty(&call->recvmsg_link))
  33                 return;
  34
  35         rcu_read_lock();
  36
  37         rx = rcu_dereference(call->socket);
  38         sk = &rx->sk;
  39         if (rx && sk->sk_state < RXRPC_CLOSE) {
  40                 if (call->notify_rx) {
  41                         call->notify_rx(sk, call, call->user_call_ID);
  42                 } else {
  43                         write_lock_bh(&rx->recvmsg_lock);
  44                         if (list_empty(&call->recvmsg_link)) {
  45                                 rxrpc_get_call(call, rxrpc_call_got);
  46                                 list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
  47                         }
  48                         write_unlock_bh(&rx->recvmsg_lock);
  49
  50                         if (!sock_flag(sk, SOCK_DEAD)) {
  51                                 _debug("call %ps", sk->sk_data_ready);
  52                                 sk->sk_data_ready(sk);
  53                         }
  54                 }
  55         }
  56
  57         rcu_read_unlock();
  58         _leave("");
  59 }
  60
  61 /*
  62  * Pass a call terminating message to userspace.
  63  */
  64 static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
  65 {
  66         u32 tmp = 0;
  67         int ret;
  68
  69         switch (call->completion) {
  70         case RXRPC_CALL_SUCCEEDED:
  71                 ret = 0;
  72                 if (rxrpc_is_service_call(call))
  73                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
  74                 break;
  75         case RXRPC_CALL_REMOTELY_ABORTED:
  76                 tmp = call->abort_code;
  77                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
  78                 break;
  79         case RXRPC_CALL_LOCALLY_ABORTED:
  80                 tmp = call->abort_code;
  81                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
  82                 break;
  83         case RXRPC_CALL_NETWORK_ERROR:
  84                 tmp = call->error;
  85                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
  86                 break;
  87         case RXRPC_CALL_LOCAL_ERROR:
  88                 tmp = call->error;
  89                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
  90                 break;
  91         default:
  92                 pr_err("Invalid terminal call state %u\n", call->state);
  93                 BUG();
  94                 break;
  95         }
  96
  97         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack,
  98                             call->rx_pkt_offset, call->rx_pkt_len, ret);
  99         return ret;
 100 }
 101
 102 /*
 103  * Pass back notification of a new call.  The call is added to the
 104  * to-be-accepted list.  This means that the next call to be accepted might not
 105  * be the last call seen awaiting acceptance, but unless we leave this on the
 106  * front of the queue and block all other messages until someone gives us a
 107  * user_ID for it, there's not a lot we can do.
 108  */
 109 static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx,
 110                                   struct rxrpc_call *call,
 111                                   struct msghdr *msg, int flags)
 112 {
 113         int tmp = 0, ret;
 114
 115         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp);
 116
 117         if (ret == 0 && !(flags & MSG_PEEK)) {
 118                 _debug("to be accepted");
 119                 write_lock_bh(&rx->recvmsg_lock);
 120                 list_del_init(&call->recvmsg_link);
 121                 write_unlock_bh(&rx->recvmsg_lock);
 122
 123                 rxrpc_get_call(call, rxrpc_call_got);
 124                 write_lock(&rx->call_lock);
 125                 list_add_tail(&call->accept_link, &rx->to_be_accepted);
 126                 write_unlock(&rx->call_lock);
 127         }
 128
 129         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret);
 130         return ret;
 131 }
 132
 133 /*
 134  * End the packet reception phase.
 135  */
 136 static void rxrpc_end_rx_phase(struct rxrpc_call *call)
 137 {
 138         _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
 139
 140         trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top);
 141         ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
 142
 143         if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
 144                 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, true, false);
 145                 rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
 146         }
 147
 148         write_lock_bh(&call->state_lock);
 149
 150         switch (call->state) {
 151         case RXRPC_CALL_CLIENT_RECV_REPLY:
 152                 __rxrpc_call_completed(call);
 153                 break;
 154
 155         case RXRPC_CALL_SERVER_RECV_REQUEST:
 156                 call->tx_phase = true;
 157                 call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
 158                 break;
 159         default:
 160                 break;
 161         }
 162
 163         write_unlock_bh(&call->state_lock);
 164 }
 165
 166 /*
 167  * Discard a packet we've used up and advance the Rx window by one.
 168  */
 169 static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
 170 {
 171         struct rxrpc_skb_priv *sp;
 172         struct sk_buff *skb;
 173         rxrpc_serial_t serial;
 174         rxrpc_seq_t hard_ack, top;
 175         u8 flags;
 176         int ix;
 177
 178         _enter("%d", call->debug_id);
 179
 180         hard_ack = call->rx_hard_ack;
 181         top = smp_load_acquire(&call->rx_top);
 182         ASSERT(before(hard_ack, top));
 183
 184         hard_ack++;
 185         ix = hard_ack & RXRPC_RXTX_BUFF_MASK;
 186         skb = call->rxtx_buffer[ix];
 187         rxrpc_see_skb(skb, rxrpc_skb_rx_rotated);
 188         sp = rxrpc_skb(skb);
 189         flags = sp->hdr.flags;
 190         serial = sp->hdr.serial;
 191         if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO)
 192                 serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1;
 193
 194         call->rxtx_buffer[ix] = NULL;
 195         call->rxtx_annotations[ix] = 0;
 196         /* Barrier against rxrpc_input_data(). */
 197         smp_store_release(&call->rx_hard_ack, hard_ack);
 198
 199         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 200
 201         _debug("%u,%u,%02x", hard_ack, top, flags);
 202         trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
 203         if (flags & RXRPC_LAST_PACKET)
 204                 rxrpc_end_rx_phase(call);
 205 }
 206
 207 /*
 208  * Decrypt and verify a (sub)packet.  The packet's length may be changed due to
 209  * padding, but if this is the case, the packet length will be resident in the
 210  * socket buffer.  Note that we can't modify the master skb info as the skb may
 211  * be the home to multiple subpackets.
 212  */
 213 static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 214                                u8 annotation,
 215                                unsigned int offset, unsigned int len)
 216 {
 217         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 218         rxrpc_seq_t seq = sp->hdr.seq;
 219         u16 cksum = sp->hdr.cksum;
 220
 221         _enter("");
 222
 223         /* For all but the head jumbo subpacket, the security checksum is in a
 224          * jumbo header immediately prior to the data.
 225          */
 226         if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) {
 227                 __be16 tmp;
 228                 if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
 229                         BUG();
 230                 cksum = ntohs(tmp);
 231                 seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1;
 232         }
 233
 234         return call->conn->security->verify_packet(call, skb, offset, len,
 235                                                    seq, cksum);
 236 }
 237
 238 /*
 239  * Locate the data within a packet.  This is complicated by:
 240  *
 241  * (1) An skb may contain a jumbo packet - so we have to find the appropriate
 242  *     subpacket.
 243  *
 244  * (2) The (sub)packets may be encrypted and, if so, the encrypted portion
 245  *     contains an extra header which includes the true length of the data,
 246  *     excluding any encrypted padding.
 247  */
 248 static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
 249                              u8 *_annotation,
 250                              unsigned int *_offset, unsigned int *_len)
 251 {
 252         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 253         unsigned int offset = *_offset;
 254         unsigned int len = *_len;
 255         int ret;
 256         u8 annotation = *_annotation;
 257
 258         /* Locate the subpacket */
 259         offset = sp->offset;
 260         len = skb->len - sp->offset;
 261         if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) {
 262                 offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) *
 263                            RXRPC_JUMBO_SUBPKTLEN);
 264                 len = (annotation & RXRPC_RX_ANNO_JLAST) ?
 265                         skb->len - offset : RXRPC_JUMBO_SUBPKTLEN;
 266         }
 267
 268         if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
 269                 ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
 270                 if (ret < 0)
 271                         return ret;
 272                 *_annotation |= RXRPC_RX_ANNO_VERIFIED;
 273         }
 274
 275         *_offset = offset;
 276         *_len = len;
 277         call->conn->security->locate_data(call, skb, _offset, _len);
 278         return 0;
 279 }
 280
 281 /*
 282  * Deliver messages to a call.  This keeps processing packets until the buffer
 283  * is filled and we find either more DATA (returns 0) or the end of the DATA
 284  * (returns 1).  If more packets are required, it returns -EAGAIN.
 285  */
 286 static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
 287                               struct msghdr *msg, struct iov_iter *iter,
 288                               size_t len, int flags, size_t *_offset)
 289 {
 290         struct rxrpc_skb_priv *sp;
 291         struct sk_buff *skb;
 292         rxrpc_seq_t hard_ack, top, seq;
 293         size_t remain;
 294         bool last;
 295         unsigned int rx_pkt_offset, rx_pkt_len;
 296         int ix, copy, ret = -EAGAIN, ret2;
 297
 298         rx_pkt_offset = call->rx_pkt_offset;
 299         rx_pkt_len = call->rx_pkt_len;
 300
 301         if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
 302                 seq = call->rx_hard_ack;
 303                 ret = 1;
 304                 goto done;
 305         }
 306
 307         /* Barriers against rxrpc_input_data(). */
 308         hard_ack = call->rx_hard_ack;
 309         top = smp_load_acquire(&call->rx_top);
 310         for (seq = hard_ack + 1; before_eq(seq, top); seq++) {
 311                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 312                 skb = call->rxtx_buffer[ix];
 313                 if (!skb) {
 314                         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq,
 315                                             rx_pkt_offset, rx_pkt_len, 0);
 316                         break;
 317                 }
 318                 smp_rmb();
 319                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 320                 sp = rxrpc_skb(skb);
 321
 322                 if (!(flags & MSG_PEEK))
 323                         trace_rxrpc_receive(call, rxrpc_receive_front,
 324                                             sp->hdr.serial, seq);
 325
 326                 if (msg)
 327                         sock_recv_timestamp(msg, sock->sk, skb);
 328
 329                 if (rx_pkt_offset == 0) {
 330                         ret2 = rxrpc_locate_data(call, skb,
 331                                                  &call->rxtx_annotations[ix],
 332                                                  &rx_pkt_offset, &rx_pkt_len);
 333                         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq,
 334                                             rx_pkt_offset, rx_pkt_len, ret2);
 335                         if (ret2 < 0) {
 336                                 ret = ret2;
 337                                 goto out;
 338                         }
 339                 } else {
 340                         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq,
 341                                             rx_pkt_offset, rx_pkt_len, 0);
 342                 }
 343
 344                 /* We have to handle short, empty and used-up DATA packets. */
 345                 remain = len - *_offset;
 346                 copy = rx_pkt_len;
 347                 if (copy > remain)
 348                         copy = remain;
 349                 if (copy > 0) {
 350                         ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
 351                                                       copy);
 352                         if (ret2 < 0) {
 353                                 ret = ret2;
 354                                 goto out;
 355                         }
 356
 357                         /* handle piecemeal consumption of data packets */
 358                         rx_pkt_offset += copy;
 359                         rx_pkt_len -= copy;
 360                         *_offset += copy;
 361                 }
 362
 363                 if (rx_pkt_len > 0) {
 364                         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq,
 365                                             rx_pkt_offset, rx_pkt_len, 0);
 366                         ASSERTCMP(*_offset, ==, len);
 367                         ret = 0;
 368                         break;
 369                 }
 370
 371                 /* The whole packet has been transferred. */
 372                 last = sp->hdr.flags & RXRPC_LAST_PACKET;
 373                 if (!(flags & MSG_PEEK))
 374                         rxrpc_rotate_rx_window(call);
 375                 rx_pkt_offset = 0;
 376                 rx_pkt_len = 0;
 377
 378                 if (last) {
 379                         ASSERTCMP(seq, ==, READ_ONCE(call->rx_top));
 380                         ret = 1;
 381                         goto out;
 382                 }
 383         }
 384
 385 out:
 386         if (!(flags & MSG_PEEK)) {
 387                 call->rx_pkt_offset = rx_pkt_offset;
 388                 call->rx_pkt_len = rx_pkt_len;
 389         }
 390 done:
 391         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq,
 392                             rx_pkt_offset, rx_pkt_len, ret);
 393         return ret;
 394 }
 395
 396 /*
 397  * Receive a message from an RxRPC socket
 398  * - we need to be careful about two or more threads calling recvmsg
 399  *   simultaneously
 400  */
 401 int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 402                   int flags)
 403 {
 404         struct rxrpc_call *call;
 405         struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 406         struct list_head *l;
 407         size_t copied = 0;
 408         long timeo;
 409         int ret;
 410
 411         DEFINE_WAIT(wait);
 412
 413         trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0);
 414
 415         if (flags & (MSG_OOB | MSG_TRUNC))
 416                 return -EOPNOTSUPP;
 417
 418         timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
 419
 420 try_again:
 421         lock_sock(&rx->sk);
 422
 423         /* Return immediately if a client socket has no outstanding calls */
 424         if (RB_EMPTY_ROOT(&rx->calls) &&
 425             list_empty(&rx->recvmsg_q) &&
 426             rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
 427                 release_sock(&rx->sk);
 428                 return -ENODATA;
 429         }
 430
 431         if (list_empty(&rx->recvmsg_q)) {
 432                 ret = -EWOULDBLOCK;
 433                 if (timeo == 0) {
 434                         call = NULL;
 435                         goto error_no_call;
 436                 }
 437
 438                 release_sock(&rx->sk);
 439
 440                 /* Wait for something to happen */
 441                 prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
 442                                           TASK_INTERRUPTIBLE);
 443                 ret = sock_error(&rx->sk);
 444                 if (ret)
 445                         goto wait_error;
 446
 447                 if (list_empty(&rx->recvmsg_q)) {
 448                         if (signal_pending(current))
 449                                 goto wait_interrupted;
 450                         trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait,
 451                                             0, 0, 0, 0);
 452                         timeo = schedule_timeout(timeo);
 453                 }
 454                 finish_wait(sk_sleep(&rx->sk), &wait);
 455                 goto try_again;
 456         }
 457
 458         /* Find the next call and dequeue it if we're not just peeking.  If we
 459          * do dequeue it, that comes with a ref that we will need to release.
 460          */
 461         write_lock_bh(&rx->recvmsg_lock);
 462         l = rx->recvmsg_q.next;
 463         call = list_entry(l, struct rxrpc_call, recvmsg_link);
 464         if (!(flags & MSG_PEEK))
 465                 list_del_init(&call->recvmsg_link);
 466         else
 467                 rxrpc_get_call(call, rxrpc_call_got);
 468         write_unlock_bh(&rx->recvmsg_lock);
 469
 470         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0);
 471
 472         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 473                 BUG();
 474
 475         if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 476                 if (flags & MSG_CMSG_COMPAT) {
 477                         unsigned int id32 = call->user_call_ID;
 478
 479                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
 480                                        sizeof(unsigned int), &id32);
 481                 } else {
 482                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
 483                                        sizeof(unsigned long),
 484                                        &call->user_call_ID);
 485                 }
 486                 if (ret < 0)
 487                         goto error;
 488         }
 489
 490         if (msg->msg_name) {
 491                 size_t len = sizeof(call->conn->params.peer->srx);
 492                 memcpy(msg->msg_name, &call->conn->params.peer->srx, len);
 493                 msg->msg_namelen = len;
 494         }
 495
 496         switch (call->state) {
 497         case RXRPC_CALL_SERVER_ACCEPTING:
 498                 ret = rxrpc_recvmsg_new_call(rx, call, msg, flags);
 499                 break;
 500         case RXRPC_CALL_CLIENT_RECV_REPLY:
 501         case RXRPC_CALL_SERVER_RECV_REQUEST:
 502         case RXRPC_CALL_SERVER_ACK_REQUEST:
 503                 ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
 504                                          flags, &copied);
 505                 if (ret == -EAGAIN)
 506                         ret = 0;
 507
 508                 if (after(call->rx_top, call->rx_hard_ack) &&
 509                     call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
 510                         rxrpc_notify_socket(call);
 511                 break;
 512         default:
 513                 ret = 0;
 514                 break;
 515         }
 516
 517         if (ret < 0)
 518                 goto error;
 519
 520         if (call->state == RXRPC_CALL_COMPLETE) {
 521                 ret = rxrpc_recvmsg_term(call, msg);
 522                 if (ret < 0)
 523                         goto error;
 524                 if (!(flags & MSG_PEEK))
 525                         rxrpc_release_call(rx, call);
 526                 msg->msg_flags |= MSG_EOR;
 527                 ret = 1;
 528         }
 529
 530         if (ret == 0)
 531                 msg->msg_flags |= MSG_MORE;
 532         else
 533                 msg->msg_flags &= ~MSG_MORE;
 534         ret = copied;
 535
 536 error:
 537         rxrpc_put_call(call, rxrpc_call_put);
 538 error_no_call:
 539         release_sock(&rx->sk);
 540         trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
 541         return ret;
 542
 543 wait_interrupted:
 544         ret = sock_intr_errno(timeo);
 545 wait_error:
 546         finish_wait(sk_sleep(&rx->sk), &wait);
 547         call = NULL;
 548         goto error_no_call;
 549 }
 550
 551 /**
 552  * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
 553  * @sock: The socket that the call exists on
 554  * @call: The call to send data through
 555  * @buf: The buffer to receive into
 556  * @size: The size of the buffer, including data already read
 557  * @_offset: The running offset into the buffer.
 558  * @want_more: True if more data is expected to be read
 559  * @_abort: Where the abort code is stored if -ECONNABORTED is returned
 560  *
 561  * Allow a kernel service to receive data and pick up information about the
 562  * state of a call.  Returns 0 if got what was asked for and there's more
 563  * available, 1 if we got what was asked for and we're at the end of the data
 564  * and -EAGAIN if we need more data.
 565  *
 566  * Note that we may return -EAGAIN to drain empty packets at the end of the
 567  * data, even if we've already copied over the requested data.
 568  *
 569  * This function adds the amount it transfers to *_offset, so this should be
 570  * precleared as appropriate.  Note that the amount remaining in the buffer is
 571  * taken to be size - *_offset.
 572  *
 573  * *_abort should also be initialised to 0.
 574  */
 575 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 576                            void *buf, size_t size, size_t *_offset,
 577                            bool want_more, u32 *_abort)
 578 {
 579         struct iov_iter iter;
 580         struct kvec iov;
 581         int ret;
 582
 583         _enter("{%d,%s},%zu/%zu,%d",
 584                call->debug_id, rxrpc_call_states[call->state],
 585                *_offset, size, want_more);
 586
 587         ASSERTCMP(*_offset, <=, size);
 588         ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
 589
 590         iov.iov_base = buf + *_offset;
 591         iov.iov_len = size - *_offset;
 592         iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset);
 593
 594         lock_sock(sock->sk);
 595
 596         switch (call->state) {
 597         case RXRPC_CALL_CLIENT_RECV_REPLY:
 598         case RXRPC_CALL_SERVER_RECV_REQUEST:
 599         case RXRPC_CALL_SERVER_ACK_REQUEST:
 600                 ret = rxrpc_recvmsg_data(sock, call, NULL, &iter, size, 0,
 601                                          _offset);
 602                 if (ret < 0)
 603                         goto out;
 604
 605                 /* We can only reach here with a partially full buffer if we
 606                  * have reached the end of the data.  We must otherwise have a
 607                  * full buffer or have been given -EAGAIN.
 608                  */
 609                 if (ret == 1) {
 610                         if (*_offset < size)
 611                                 goto short_data;
 612                         if (!want_more)
 613                                 goto read_phase_complete;
 614                         ret = 0;
 615                         goto out;
 616                 }
 617
 618                 if (!want_more)
 619                         goto excess_data;
 620                 goto out;
 621
 622         case RXRPC_CALL_COMPLETE:
 623                 goto call_complete;
 624
 625         default:
 626                 ret = -EINPROGRESS;
 627                 goto out;
 628         }
 629
 630 read_phase_complete:
 631         ret = 1;
 632 out:
 633         release_sock(sock->sk);
 634         _leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
 635         return ret;
 636
 637 short_data:
 638         ret = -EBADMSG;
 639         goto out;
 640 excess_data:
 641         ret = -EMSGSIZE;
 642         goto out;
 643 call_complete:
 644         *_abort = call->abort_code;
 645         ret = call->error;
 646         if (call->completion == RXRPC_CALL_SUCCEEDED) {
 647                 ret = 1;
 648                 if (size > 0)
 649                         ret = -ECONNRESET;
 650         }
 651         goto out;
 652 }
 653 EXPORT_SYMBOL(rxrpc_kernel_recv_data);