fs/afs/rxrpc.c

   1 /* Maintain an RxRPC server socket to do AFS communications through
   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 #include <net/sock.h>
  13 #include <net/af_rxrpc.h>
  14 #include <rxrpc/packet.h>
  15 #include "internal.h"
  16 #include "afs_cm.h"
  17
  18 static struct socket *afs_socket; /* my RxRPC socket */
  19 static struct workqueue_struct *afs_async_calls;
  20 static atomic_t afs_outstanding_calls;
  21 static atomic_t afs_outstanding_skbs;
  22
  23 static void afs_wake_up_call_waiter(struct afs_call *);
  24 static int afs_wait_for_call_to_complete(struct afs_call *);
  25 static void afs_wake_up_async_call(struct afs_call *);
  26 static int afs_dont_wait_for_call_to_complete(struct afs_call *);
  27 static void afs_process_async_call(struct work_struct *);
  28 static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
  29 static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
  30
  31 /* synchronous call management */
  32 const struct afs_wait_mode afs_sync_call = {
  33         .rx_wakeup      = afs_wake_up_call_waiter,
  34         .wait           = afs_wait_for_call_to_complete,
  35 };
  36
  37 /* asynchronous call management */
  38 const struct afs_wait_mode afs_async_call = {
  39         .rx_wakeup      = afs_wake_up_async_call,
  40         .wait           = afs_dont_wait_for_call_to_complete,
  41 };
  42
  43 /* asynchronous incoming call management */
  44 static const struct afs_wait_mode afs_async_incoming_call = {
  45         .rx_wakeup      = afs_wake_up_async_call,
  46 };
  47
  48 /* asynchronous incoming call initial processing */
  49 static const struct afs_call_type afs_RXCMxxxx = {
  50         .name           = "CB.xxxx",
  51         .deliver        = afs_deliver_cm_op_id,
  52         .abort_to_error = afs_abort_to_error,
  53 };
  54
  55 static void afs_collect_incoming_call(struct work_struct *);
  56
  57 static struct sk_buff_head afs_incoming_calls;
  58 static DECLARE_WORK(afs_collect_incoming_call_work, afs_collect_incoming_call);
  59
  60 /*
  61  * open an RxRPC socket and bind it to be a server for callback notifications
  62  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
  63  */
  64 int afs_open_socket(void)
  65 {
  66         struct sockaddr_rxrpc srx;
  67         struct socket *socket;
  68         int ret;
  69
  70         _enter("");
  71
  72         skb_queue_head_init(&afs_incoming_calls);
  73
  74         afs_async_calls = create_singlethread_workqueue("kafsd");
  75         if (!afs_async_calls) {
  76                 _leave(" = -ENOMEM [wq]");
  77                 return -ENOMEM;
  78         }
  79
  80         ret = sock_create_kern(AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
  81         if (ret < 0) {
  82                 destroy_workqueue(afs_async_calls);
  83                 _leave(" = %d [socket]", ret);
  84                 return ret;
  85         }
  86
  87         socket->sk->sk_allocation = GFP_NOFS;
  88
  89         /* bind the callback manager's address to make this a server socket */
  90         srx.srx_family                  = AF_RXRPC;
  91         srx.srx_service                 = CM_SERVICE;
  92         srx.transport_type              = SOCK_DGRAM;
  93         srx.transport_len               = sizeof(srx.transport.sin);
  94         srx.transport.sin.sin_family    = AF_INET;
  95         srx.transport.sin.sin_port      = htons(AFS_CM_PORT);
  96         memset(&srx.transport.sin.sin_addr, 0,
  97                sizeof(srx.transport.sin.sin_addr));
  98
  99         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
 100         if (ret < 0) {
 101                 sock_release(socket);
 102                 _leave(" = %d [bind]", ret);
 103                 return ret;
 104         }
 105
 106         rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
 107
 108         afs_socket = socket;
 109         _leave(" = 0");
 110         return 0;
 111 }
 112
 113 /*
 114  * close the RxRPC socket AFS was using
 115  */
 116 void afs_close_socket(void)
 117 {
 118         _enter("");
 119
 120         sock_release(afs_socket);
 121
 122         _debug("dework");
 123         destroy_workqueue(afs_async_calls);
 124
 125         ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
 126         ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0);
 127         _leave("");
 128 }
 129
 130 /*
 131  * note that the data in a socket buffer is now delivered and that the buffer
 132  * should be freed
 133  */
 134 static void afs_data_delivered(struct sk_buff *skb)
 135 {
 136         if (!skb) {
 137                 _debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
 138                 dump_stack();
 139         } else {
 140                 _debug("DLVR %p{%u} [%d]",
 141                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 142                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 143                         BUG();
 144                 rxrpc_kernel_data_delivered(skb);
 145         }
 146 }
 147
 148 /*
 149  * free a socket buffer
 150  */
 151 static void afs_free_skb(struct sk_buff *skb)
 152 {
 153         if (!skb) {
 154                 _debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
 155                 dump_stack();
 156         } else {
 157                 _debug("FREE %p{%u} [%d]",
 158                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 159                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 160                         BUG();
 161                 rxrpc_kernel_free_skb(skb);
 162         }
 163 }
 164
 165 /*
 166  * free a call
 167  */
 168 static void afs_free_call(struct afs_call *call)
 169 {
 170         _debug("DONE %p{%s} [%d]",
 171                call, call->type->name, atomic_read(&afs_outstanding_calls));
 172         if (atomic_dec_return(&afs_outstanding_calls) == -1)
 173                 BUG();
 174
 175         ASSERTCMP(call->rxcall, ==, NULL);
 176         ASSERT(!work_pending(&call->async_work));
 177         ASSERT(skb_queue_empty(&call->rx_queue));
 178         ASSERT(call->type->name != NULL);
 179
 180         kfree(call->request);
 181         kfree(call);
 182 }
 183
 184 /*
 185  * allocate a call with flat request and reply buffers
 186  */
 187 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 188                                      size_t request_size, size_t reply_size)
 189 {
 190         struct afs_call *call;
 191
 192         call = kzalloc(sizeof(*call), GFP_NOFS);
 193         if (!call)
 194                 goto nomem_call;
 195
 196         _debug("CALL %p{%s} [%d]",
 197                call, type->name, atomic_read(&afs_outstanding_calls));
 198         atomic_inc(&afs_outstanding_calls);
 199
 200         call->type = type;
 201         call->request_size = request_size;
 202         call->reply_max = reply_size;
 203
 204         if (request_size) {
 205                 call->request = kmalloc(request_size, GFP_NOFS);
 206                 if (!call->request)
 207                         goto nomem_free;
 208         }
 209
 210         if (reply_size) {
 211                 call->buffer = kmalloc(reply_size, GFP_NOFS);
 212                 if (!call->buffer)
 213                         goto nomem_free;
 214         }
 215
 216         init_waitqueue_head(&call->waitq);
 217         skb_queue_head_init(&call->rx_queue);
 218         return call;
 219
 220 nomem_free:
 221         afs_free_call(call);
 222 nomem_call:
 223         return NULL;
 224 }
 225
 226 /*
 227  * clean up a call with flat buffer
 228  */
 229 void afs_flat_call_destructor(struct afs_call *call)
 230 {
 231         _enter("");
 232
 233         kfree(call->request);
 234         call->request = NULL;
 235         kfree(call->buffer);
 236         call->buffer = NULL;
 237 }
 238
 239 /*
 240  * initiate a call
 241  */
 242 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 243                   const struct afs_wait_mode *wait_mode)
 244 {
 245         struct sockaddr_rxrpc srx;
 246         struct rxrpc_call *rxcall;
 247         struct msghdr msg;
 248         struct kvec iov[1];
 249         int ret;
 250
 251         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 252
 253         ASSERT(call->type != NULL);
 254         ASSERT(call->type->name != NULL);
 255
 256         _debug("MAKE %p{%s} [%d]",
 257                call, call->type->name, atomic_read(&afs_outstanding_calls));
 258
 259         call->wait_mode = wait_mode;
 260         INIT_WORK(&call->async_work, afs_process_async_call);
 261
 262         memset(&srx, 0, sizeof(srx));
 263         srx.srx_family = AF_RXRPC;
 264         srx.srx_service = call->service_id;
 265         srx.transport_type = SOCK_DGRAM;
 266         srx.transport_len = sizeof(srx.transport.sin);
 267         srx.transport.sin.sin_family = AF_INET;
 268         srx.transport.sin.sin_port = call->port;
 269         memcpy(&srx.transport.sin.sin_addr, addr, 4);
 270
 271         /* create a call */
 272         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 273                                          (unsigned long) call, gfp);
 274         call->key = NULL;
 275         if (IS_ERR(rxcall)) {
 276                 ret = PTR_ERR(rxcall);
 277                 goto error_kill_call;
 278         }
 279
 280         call->rxcall = rxcall;
 281
 282         /* send the request */
 283         iov[0].iov_base = call->request;
 284         iov[0].iov_len  = call->request_size;
 285
 286         msg.msg_name            = NULL;
 287         msg.msg_namelen         = 0;
 288         msg.msg_iov             = (struct iovec *) iov;
 289         msg.msg_iovlen          = 1;
 290         msg.msg_control         = NULL;
 291         msg.msg_controllen      = 0;
 292         msg.msg_flags           = 0;
 293
 294         /* have to change the state *before* sending the last packet as RxRPC
 295          * might give us the reply before it returns from sending the
 296          * request */
 297         call->state = AFS_CALL_AWAIT_REPLY;
 298         ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
 299         if (ret < 0)
 300                 goto error_do_abort;
 301
 302         /* at this point, an async call may no longer exist as it may have
 303          * already completed */
 304         return wait_mode->wait(call);
 305
 306 error_do_abort:
 307         rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 308         rxrpc_kernel_end_call(rxcall);
 309         call->rxcall = NULL;
 310 error_kill_call:
 311         call->type->destructor(call);
 312         afs_free_call(call);
 313         _leave(" = %d", ret);
 314         return ret;
 315 }
 316
 317 /*
 318  * handles intercepted messages that were arriving in the socket's Rx queue
 319  * - called with the socket receive queue lock held to ensure message ordering
 320  * - called with softirqs disabled
 321  */
 322 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
 323                                struct sk_buff *skb)
 324 {
 325         struct afs_call *call = (struct afs_call *) user_call_ID;
 326
 327         _enter("%p,,%u", call, skb->mark);
 328
 329         _debug("ICPT %p{%u} [%d]",
 330                skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 331
 332         ASSERTCMP(sk, ==, afs_socket->sk);
 333         atomic_inc(&afs_outstanding_skbs);
 334
 335         if (!call) {
 336                 /* its an incoming call for our callback service */
 337                 skb_queue_tail(&afs_incoming_calls, skb);
 338                 schedule_work(&afs_collect_incoming_call_work);
 339         } else {
 340                 /* route the messages directly to the appropriate call */
 341                 skb_queue_tail(&call->rx_queue, skb);
 342                 call->wait_mode->rx_wakeup(call);
 343         }
 344
 345         _leave("");
 346 }
 347
 348 /*
 349  * deliver messages to a call
 350  */
 351 static void afs_deliver_to_call(struct afs_call *call)
 352 {
 353         struct sk_buff *skb;
 354         bool last;
 355         u32 abort_code;
 356         int ret;
 357
 358         _enter("");
 359
 360         while ((call->state == AFS_CALL_AWAIT_REPLY ||
 361                 call->state == AFS_CALL_AWAIT_OP_ID ||
 362                 call->state == AFS_CALL_AWAIT_REQUEST ||
 363                 call->state == AFS_CALL_AWAIT_ACK) &&
 364                (skb = skb_dequeue(&call->rx_queue))) {
 365                 switch (skb->mark) {
 366                 case RXRPC_SKB_MARK_DATA:
 367                         _debug("Rcv DATA");
 368                         last = rxrpc_kernel_is_data_last(skb);
 369                         ret = call->type->deliver(call, skb, last);
 370                         switch (ret) {
 371                         case 0:
 372                                 if (last &&
 373                                     call->state == AFS_CALL_AWAIT_REPLY)
 374                                         call->state = AFS_CALL_COMPLETE;
 375                                 break;
 376                         case -ENOTCONN:
 377                                 abort_code = RX_CALL_DEAD;
 378                                 goto do_abort;
 379                         case -ENOTSUPP:
 380                                 abort_code = RX_INVALID_OPERATION;
 381                                 goto do_abort;
 382                         default:
 383                                 abort_code = RXGEN_CC_UNMARSHAL;
 384                                 if (call->state != AFS_CALL_AWAIT_REPLY)
 385                                         abort_code = RXGEN_SS_UNMARSHAL;
 386                         do_abort:
 387                                 rxrpc_kernel_abort_call(call->rxcall,
 388                                                         abort_code);
 389                                 call->error = ret;
 390                                 call->state = AFS_CALL_ERROR;
 391                                 break;
 392                         }
 393                         afs_data_delivered(skb);
 394                         skb = NULL;
 395                         continue;
 396                 case RXRPC_SKB_MARK_FINAL_ACK:
 397                         _debug("Rcv ACK");
 398                         call->state = AFS_CALL_COMPLETE;
 399                         break;
 400                 case RXRPC_SKB_MARK_BUSY:
 401                         _debug("Rcv BUSY");
 402                         call->error = -EBUSY;
 403                         call->state = AFS_CALL_BUSY;
 404                         break;
 405                 case RXRPC_SKB_MARK_REMOTE_ABORT:
 406                         abort_code = rxrpc_kernel_get_abort_code(skb);
 407                         call->error = call->type->abort_to_error(abort_code);
 408                         call->state = AFS_CALL_ABORTED;
 409                         _debug("Rcv ABORT %u -> %d", abort_code, call->error);
 410                         break;
 411                 case RXRPC_SKB_MARK_NET_ERROR:
 412                         call->error = -rxrpc_kernel_get_error_number(skb);
 413                         call->state = AFS_CALL_ERROR;
 414                         _debug("Rcv NET ERROR %d", call->error);
 415                         break;
 416                 case RXRPC_SKB_MARK_LOCAL_ERROR:
 417                         call->error = -rxrpc_kernel_get_error_number(skb);
 418                         call->state = AFS_CALL_ERROR;
 419                         _debug("Rcv LOCAL ERROR %d", call->error);
 420                         break;
 421                 default:
 422                         BUG();
 423                         break;
 424                 }
 425
 426                 afs_free_skb(skb);
 427         }
 428
 429         /* make sure the queue is empty if the call is done with (we might have
 430          * aborted the call early because of an unmarshalling error) */
 431         if (call->state >= AFS_CALL_COMPLETE) {
 432                 while ((skb = skb_dequeue(&call->rx_queue)))
 433                         afs_free_skb(skb);
 434                 if (call->incoming) {
 435                         rxrpc_kernel_end_call(call->rxcall);
 436                         call->rxcall = NULL;
 437                         call->type->destructor(call);
 438                         afs_free_call(call);
 439                 }
 440         }
 441
 442         _leave("");
 443 }
 444
 445 /*
 446  * wait synchronously for a call to complete
 447  */
 448 static int afs_wait_for_call_to_complete(struct afs_call *call)
 449 {
 450         struct sk_buff *skb;
 451         int ret;
 452
 453         DECLARE_WAITQUEUE(myself, current);
 454
 455         _enter("");
 456
 457         add_wait_queue(&call->waitq, &myself);
 458         for (;;) {
 459                 set_current_state(TASK_INTERRUPTIBLE);
 460
 461                 /* deliver any messages that are in the queue */
 462                 if (!skb_queue_empty(&call->rx_queue)) {
 463                         __set_current_state(TASK_RUNNING);
 464                         afs_deliver_to_call(call);
 465                         continue;
 466                 }
 467
 468                 ret = call->error;
 469                 if (call->state >= AFS_CALL_COMPLETE)
 470                         break;
 471                 ret = -EINTR;
 472                 if (signal_pending(current))
 473                         break;
 474                 schedule();
 475         }
 476
 477         remove_wait_queue(&call->waitq, &myself);
 478         __set_current_state(TASK_RUNNING);
 479
 480         /* kill the call */
 481         if (call->state < AFS_CALL_COMPLETE) {
 482                 _debug("call incomplete");
 483                 rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
 484                 while ((skb = skb_dequeue(&call->rx_queue)))
 485                         afs_free_skb(skb);
 486         }
 487
 488         _debug("call complete");
 489         rxrpc_kernel_end_call(call->rxcall);
 490         call->rxcall = NULL;
 491         call->type->destructor(call);
 492         afs_free_call(call);
 493         _leave(" = %d", ret);
 494         return ret;
 495 }
 496
 497 /*
 498  * wake up a waiting call
 499  */
 500 static void afs_wake_up_call_waiter(struct afs_call *call)
 501 {
 502         wake_up(&call->waitq);
 503 }
 504
 505 /*
 506  * wake up an asynchronous call
 507  */
 508 static void afs_wake_up_async_call(struct afs_call *call)
 509 {
 510         _enter("");
 511         queue_work(afs_async_calls, &call->async_work);
 512 }
 513
 514 /*
 515  * put a call into asynchronous mode
 516  * - mustn't touch the call descriptor as the call my have completed by the
 517  *   time we get here
 518  */
 519 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
 520 {
 521         _enter("");
 522         return -EINPROGRESS;
 523 }
 524
 525 /*
 526  * delete an asynchronous call
 527  */
 528 static void afs_delete_async_call(struct work_struct *work)
 529 {
 530         struct afs_call *call =
 531                 container_of(work, struct afs_call, async_work);
 532
 533         _enter("");
 534
 535         afs_free_call(call);
 536
 537         _leave("");
 538 }
 539
 540 /*
 541  * perform processing on an asynchronous call
 542  * - on a multiple-thread workqueue this work item may try to run on several
 543  *   CPUs at the same time
 544  */
 545 static void afs_process_async_call(struct work_struct *work)
 546 {
 547         struct afs_call *call =
 548                 container_of(work, struct afs_call, async_work);
 549
 550         _enter("");
 551
 552         if (!skb_queue_empty(&call->rx_queue))
 553                 afs_deliver_to_call(call);
 554
 555         if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
 556                 if (call->wait_mode->async_complete)
 557                         call->wait_mode->async_complete(call->reply,
 558                                                         call->error);
 559                 call->reply = NULL;
 560
 561                 /* kill the call */
 562                 rxrpc_kernel_end_call(call->rxcall);
 563                 call->rxcall = NULL;
 564                 if (call->type->destructor)
 565                         call->type->destructor(call);
 566
 567                 /* we can't just delete the call because the work item may be
 568                  * queued */
 569                 PREPARE_WORK(&call->async_work, afs_delete_async_call);
 570                 queue_work(afs_async_calls, &call->async_work);
 571         }
 572
 573         _leave("");
 574 }
 575
 576 /*
 577  * empty a socket buffer into a flat reply buffer
 578  */
 579 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
 580 {
 581         size_t len = skb->len;
 582
 583         if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
 584                 BUG();
 585         call->reply_size += len;
 586 }
 587
 588 /*
 589  * accept the backlog of incoming calls
 590  */
 591 static void afs_collect_incoming_call(struct work_struct *work)
 592 {
 593         struct rxrpc_call *rxcall;
 594         struct afs_call *call = NULL;
 595         struct sk_buff *skb;
 596
 597         while ((skb = skb_dequeue(&afs_incoming_calls))) {
 598                 _debug("new call");
 599
 600                 /* don't need the notification */
 601                 afs_free_skb(skb);
 602
 603                 if (!call) {
 604                         call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
 605                         if (!call) {
 606                                 rxrpc_kernel_reject_call(afs_socket);
 607                                 return;
 608                         }
 609
 610                         INIT_WORK(&call->async_work, afs_process_async_call);
 611                         call->wait_mode = &afs_async_incoming_call;
 612                         call->type = &afs_RXCMxxxx;
 613                         init_waitqueue_head(&call->waitq);
 614                         skb_queue_head_init(&call->rx_queue);
 615                         call->state = AFS_CALL_AWAIT_OP_ID;
 616
 617                         _debug("CALL %p{%s} [%d]",
 618                                call, call->type->name,
 619                                atomic_read(&afs_outstanding_calls));
 620                         atomic_inc(&afs_outstanding_calls);
 621                 }
 622
 623                 rxcall = rxrpc_kernel_accept_call(afs_socket,
 624                                                   (unsigned long) call);
 625                 if (!IS_ERR(rxcall)) {
 626                         call->rxcall = rxcall;
 627                         call = NULL;
 628                 }
 629         }
 630
 631         if (call)
 632                 afs_free_call(call);
 633 }
 634
 635 /*
 636  * grab the operation ID from an incoming cache manager call
 637  */
 638 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 639                                 bool last)
 640 {
 641         size_t len = skb->len;
 642         void *oibuf = (void *) &call->operation_ID;
 643
 644         _enter("{%u},{%zu},%d", call->offset, len, last);
 645
 646         ASSERTCMP(call->offset, <, 4);
 647
 648         /* the operation ID forms the first four bytes of the request data */
 649         len = min_t(size_t, len, 4 - call->offset);
 650         if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
 651                 BUG();
 652         if (!pskb_pull(skb, len))
 653                 BUG();
 654         call->offset += len;
 655
 656         if (call->offset < 4) {
 657                 if (last) {
 658                         _leave(" = -EBADMSG [op ID short]");
 659                         return -EBADMSG;
 660                 }
 661                 _leave(" = 0 [incomplete]");
 662                 return 0;
 663         }
 664
 665         call->state = AFS_CALL_AWAIT_REQUEST;
 666
 667         /* ask the cache manager to route the call (it'll change the call type
 668          * if successful) */
 669         if (!afs_cm_incoming_call(call))
 670                 return -ENOTSUPP;
 671
 672         /* pass responsibility for the remainer of this message off to the
 673          * cache manager op */
 674         return call->type->deliver(call, skb, last);
 675 }
 676
 677 /*
 678  * send an empty reply
 679  */
 680 void afs_send_empty_reply(struct afs_call *call)
 681 {
 682         struct msghdr msg;
 683         struct iovec iov[1];
 684
 685         _enter("");
 686
 687         iov[0].iov_base         = NULL;
 688         iov[0].iov_len          = 0;
 689         msg.msg_name            = NULL;
 690         msg.msg_namelen         = 0;
 691         msg.msg_iov             = iov;
 692         msg.msg_iovlen          = 0;
 693         msg.msg_control         = NULL;
 694         msg.msg_controllen      = 0;
 695         msg.msg_flags           = 0;
 696
 697         call->state = AFS_CALL_AWAIT_ACK;
 698         switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
 699         case 0:
 700                 _leave(" [replied]");
 701                 return;
 702
 703         case -ENOMEM:
 704                 _debug("oom");
 705                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 706         default:
 707                 rxrpc_kernel_end_call(call->rxcall);
 708                 call->rxcall = NULL;
 709                 call->type->destructor(call);
 710                 afs_free_call(call);
 711                 _leave(" [error]");
 712                 return;
 713         }
 714 }
 715
 716 /*
 717  * send a simple reply
 718  */
 719 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 720 {
 721         struct msghdr msg;
 722         struct iovec iov[1];
 723
 724         _enter("");
 725
 726         iov[0].iov_base         = (void *) buf;
 727         iov[0].iov_len          = len;
 728         msg.msg_name            = NULL;
 729         msg.msg_namelen         = 0;
 730         msg.msg_iov             = iov;
 731         msg.msg_iovlen          = 1;
 732         msg.msg_control         = NULL;
 733         msg.msg_controllen      = 0;
 734         msg.msg_flags           = 0;
 735
 736         call->state = AFS_CALL_AWAIT_ACK;
 737         switch (rxrpc_kernel_send_data(call->rxcall, &msg, len)) {
 738         case 0:
 739                 _leave(" [replied]");
 740                 return;
 741
 742         case -ENOMEM:
 743                 _debug("oom");
 744                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 745         default:
 746                 rxrpc_kernel_end_call(call->rxcall);
 747                 call->rxcall = NULL;
 748                 call->type->destructor(call);
 749                 afs_free_call(call);
 750                 _leave(" [error]");
 751                 return;
 752         }
 753 }
 754
 755 /*
 756  * extract a piece of data from the received data socket buffers
 757  */
 758 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 759                      bool last, void *buf, size_t count)
 760 {
 761         size_t len = skb->len;
 762
 763         _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
 764
 765         ASSERTCMP(call->offset, <, count);
 766
 767         len = min_t(size_t, len, count - call->offset);
 768         if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
 769             !pskb_pull(skb, len))
 770                 BUG();
 771         call->offset += len;
 772
 773         if (call->offset < count) {
 774                 if (last) {
 775                         _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
 776                         return -EBADMSG;
 777                 }
 778                 _leave(" = -EAGAIN");
 779                 return -EAGAIN;
 780         }
 781         return 0;
 782 }