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 <linux/slab.h>
  13 #include <net/sock.h>
  14 #include <net/af_rxrpc.h>
  15 #include <rxrpc/packet.h>
  16 #include "internal.h"
  17 #include "afs_cm.h"
  18
  19 static struct socket *afs_socket; /* my RxRPC socket */
  20 static struct workqueue_struct *afs_async_calls;
  21 static atomic_t afs_outstanding_calls;
  22 static atomic_t afs_outstanding_skbs;
  23
  24 static void afs_wake_up_call_waiter(struct afs_call *);
  25 static int afs_wait_for_call_to_complete(struct afs_call *);
  26 static void afs_wake_up_async_call(struct afs_call *);
  27 static int afs_dont_wait_for_call_to_complete(struct afs_call *);
  28 static void afs_process_async_call(struct work_struct *);
  29 static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
  30 static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
  31
  32 /* synchronous call management */
  33 const struct afs_wait_mode afs_sync_call = {
  34         .rx_wakeup      = afs_wake_up_call_waiter,
  35         .wait           = afs_wait_for_call_to_complete,
  36 };
  37
  38 /* asynchronous call management */
  39 const struct afs_wait_mode afs_async_call = {
  40         .rx_wakeup      = afs_wake_up_async_call,
  41         .wait           = afs_dont_wait_for_call_to_complete,
  42 };
  43
  44 /* asynchronous incoming call management */
  45 static const struct afs_wait_mode afs_async_incoming_call = {
  46         .rx_wakeup      = afs_wake_up_async_call,
  47 };
  48
  49 /* asynchronous incoming call initial processing */
  50 static const struct afs_call_type afs_RXCMxxxx = {
  51         .name           = "CB.xxxx",
  52         .deliver        = afs_deliver_cm_op_id,
  53         .abort_to_error = afs_abort_to_error,
  54 };
  55
  56 static void afs_collect_incoming_call(struct work_struct *);
  57
  58 static struct sk_buff_head afs_incoming_calls;
  59 static DECLARE_WORK(afs_collect_incoming_call_work, afs_collect_incoming_call);
  60
  61 /*
  62  * open an RxRPC socket and bind it to be a server for callback notifications
  63  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
  64  */
  65 int afs_open_socket(void)
  66 {
  67         struct sockaddr_rxrpc srx;
  68         struct socket *socket;
  69         int ret;
  70
  71         _enter("");
  72
  73         skb_queue_head_init(&afs_incoming_calls);
  74
  75         afs_async_calls = create_singlethread_workqueue("kafsd");
  76         if (!afs_async_calls) {
  77                 _leave(" = -ENOMEM [wq]");
  78                 return -ENOMEM;
  79         }
  80
  81         ret = sock_create_kern(AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
  82         if (ret < 0) {
  83                 destroy_workqueue(afs_async_calls);
  84                 _leave(" = %d [socket]", ret);
  85                 return ret;
  86         }
  87
  88         socket->sk->sk_allocation = GFP_NOFS;
  89
  90         /* bind the callback manager's address to make this a server socket */
  91         srx.srx_family                  = AF_RXRPC;
  92         srx.srx_service                 = CM_SERVICE;
  93         srx.transport_type              = SOCK_DGRAM;
  94         srx.transport_len               = sizeof(srx.transport.sin);
  95         srx.transport.sin.sin_family    = AF_INET;
  96         srx.transport.sin.sin_port      = htons(AFS_CM_PORT);
  97         memset(&srx.transport.sin.sin_addr, 0,
  98                sizeof(srx.transport.sin.sin_addr));
  99
 100         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
 101         if (ret < 0) {
 102                 sock_release(socket);
 103                 destroy_workqueue(afs_async_calls);
 104                 _leave(" = %d [bind]", ret);
 105                 return ret;
 106         }
 107
 108         rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
 109
 110         afs_socket = socket;
 111         _leave(" = 0");
 112         return 0;
 113 }
 114
 115 /*
 116  * close the RxRPC socket AFS was using
 117  */
 118 void afs_close_socket(void)
 119 {
 120         _enter("");
 121
 122         sock_release(afs_socket);
 123
 124         _debug("dework");
 125         destroy_workqueue(afs_async_calls);
 126
 127         ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
 128         ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0);
 129         _leave("");
 130 }
 131
 132 /*
 133  * note that the data in a socket buffer is now delivered and that the buffer
 134  * should be freed
 135  */
 136 static void afs_data_delivered(struct sk_buff *skb)
 137 {
 138         if (!skb) {
 139                 _debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
 140                 dump_stack();
 141         } else {
 142                 _debug("DLVR %p{%u} [%d]",
 143                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 144                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 145                         BUG();
 146                 rxrpc_kernel_data_delivered(skb);
 147         }
 148 }
 149
 150 /*
 151  * free a socket buffer
 152  */
 153 static void afs_free_skb(struct sk_buff *skb)
 154 {
 155         if (!skb) {
 156                 _debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
 157                 dump_stack();
 158         } else {
 159                 _debug("FREE %p{%u} [%d]",
 160                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 161                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 162                         BUG();
 163                 rxrpc_kernel_free_skb(skb);
 164         }
 165 }
 166
 167 /*
 168  * free a call
 169  */
 170 static void afs_free_call(struct afs_call *call)
 171 {
 172         _debug("DONE %p{%s} [%d]",
 173                call, call->type->name, atomic_read(&afs_outstanding_calls));
 174         if (atomic_dec_return(&afs_outstanding_calls) == -1)
 175                 BUG();
 176
 177         ASSERTCMP(call->rxcall, ==, NULL);
 178         ASSERT(!work_pending(&call->async_work));
 179         ASSERT(skb_queue_empty(&call->rx_queue));
 180         ASSERT(call->type->name != NULL);
 181
 182         kfree(call->request);
 183         kfree(call);
 184 }
 185
 186 /*
 187  * allocate a call with flat request and reply buffers
 188  */
 189 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 190                                      size_t request_size, size_t reply_size)
 191 {
 192         struct afs_call *call;
 193
 194         call = kzalloc(sizeof(*call), GFP_NOFS);
 195         if (!call)
 196                 goto nomem_call;
 197
 198         _debug("CALL %p{%s} [%d]",
 199                call, type->name, atomic_read(&afs_outstanding_calls));
 200         atomic_inc(&afs_outstanding_calls);
 201
 202         call->type = type;
 203         call->request_size = request_size;
 204         call->reply_max = reply_size;
 205
 206         if (request_size) {
 207                 call->request = kmalloc(request_size, GFP_NOFS);
 208                 if (!call->request)
 209                         goto nomem_free;
 210         }
 211
 212         if (reply_size) {
 213                 call->buffer = kmalloc(reply_size, GFP_NOFS);
 214                 if (!call->buffer)
 215                         goto nomem_free;
 216         }
 217
 218         init_waitqueue_head(&call->waitq);
 219         skb_queue_head_init(&call->rx_queue);
 220         return call;
 221
 222 nomem_free:
 223         afs_free_call(call);
 224 nomem_call:
 225         return NULL;
 226 }
 227
 228 /*
 229  * clean up a call with flat buffer
 230  */
 231 void afs_flat_call_destructor(struct afs_call *call)
 232 {
 233         _enter("");
 234
 235         kfree(call->request);
 236         call->request = NULL;
 237         kfree(call->buffer);
 238         call->buffer = NULL;
 239 }
 240
 241 /*
 242  * attach the data from a bunch of pages on an inode to a call
 243  */
 244 static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
 245                           struct kvec *iov)
 246 {
 247         struct page *pages[8];
 248         unsigned count, n, loop, offset, to;
 249         pgoff_t first = call->first, last = call->last;
 250         int ret;
 251
 252         _enter("");
 253
 254         offset = call->first_offset;
 255         call->first_offset = 0;
 256
 257         do {
 258                 _debug("attach %lx-%lx", first, last);
 259
 260                 count = last - first + 1;
 261                 if (count > ARRAY_SIZE(pages))
 262                         count = ARRAY_SIZE(pages);
 263                 n = find_get_pages_contig(call->mapping, first, count, pages);
 264                 ASSERTCMP(n, ==, count);
 265
 266                 loop = 0;
 267                 do {
 268                         msg->msg_flags = 0;
 269                         to = PAGE_SIZE;
 270                         if (first + loop >= last)
 271                                 to = call->last_to;
 272                         else
 273                                 msg->msg_flags = MSG_MORE;
 274                         iov->iov_base = kmap(pages[loop]) + offset;
 275                         iov->iov_len = to - offset;
 276                         offset = 0;
 277
 278                         _debug("- range %u-%u%s",
 279                                offset, to, msg->msg_flags ? " [more]" : "");
 280                         msg->msg_iov = (struct iovec *) iov;
 281                         msg->msg_iovlen = 1;
 282
 283                         /* have to change the state *before* sending the last
 284                          * packet as RxRPC might give us the reply before it
 285                          * returns from sending the request */
 286                         if (first + loop >= last)
 287                                 call->state = AFS_CALL_AWAIT_REPLY;
 288                         ret = rxrpc_kernel_send_data(call->rxcall, msg,
 289                                                      to - offset);
 290                         kunmap(pages[loop]);
 291                         if (ret < 0)
 292                                 break;
 293                 } while (++loop < count);
 294                 first += count;
 295
 296                 for (loop = 0; loop < count; loop++)
 297                         put_page(pages[loop]);
 298                 if (ret < 0)
 299                         break;
 300         } while (first <= last);
 301
 302         _leave(" = %d", ret);
 303         return ret;
 304 }
 305
 306 /*
 307  * initiate a call
 308  */
 309 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 310                   const struct afs_wait_mode *wait_mode)
 311 {
 312         struct sockaddr_rxrpc srx;
 313         struct rxrpc_call *rxcall;
 314         struct msghdr msg;
 315         struct kvec iov[1];
 316         int ret;
 317
 318         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 319
 320         ASSERT(call->type != NULL);
 321         ASSERT(call->type->name != NULL);
 322
 323         _debug("____MAKE %p{%s,%x} [%d]____",
 324                call, call->type->name, key_serial(call->key),
 325                atomic_read(&afs_outstanding_calls));
 326
 327         call->wait_mode = wait_mode;
 328         INIT_WORK(&call->async_work, afs_process_async_call);
 329
 330         memset(&srx, 0, sizeof(srx));
 331         srx.srx_family = AF_RXRPC;
 332         srx.srx_service = call->service_id;
 333         srx.transport_type = SOCK_DGRAM;
 334         srx.transport_len = sizeof(srx.transport.sin);
 335         srx.transport.sin.sin_family = AF_INET;
 336         srx.transport.sin.sin_port = call->port;
 337         memcpy(&srx.transport.sin.sin_addr, addr, 4);
 338
 339         /* create a call */
 340         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 341                                          (unsigned long) call, gfp);
 342         call->key = NULL;
 343         if (IS_ERR(rxcall)) {
 344                 ret = PTR_ERR(rxcall);
 345                 goto error_kill_call;
 346         }
 347
 348         call->rxcall = rxcall;
 349
 350         /* send the request */
 351         iov[0].iov_base = call->request;
 352         iov[0].iov_len  = call->request_size;
 353
 354         msg.msg_name            = NULL;
 355         msg.msg_namelen         = 0;
 356         msg.msg_iov             = (struct iovec *) iov;
 357         msg.msg_iovlen          = 1;
 358         msg.msg_control         = NULL;
 359         msg.msg_controllen      = 0;
 360         msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
 361
 362         /* have to change the state *before* sending the last packet as RxRPC
 363          * might give us the reply before it returns from sending the
 364          * request */
 365         if (!call->send_pages)
 366                 call->state = AFS_CALL_AWAIT_REPLY;
 367         ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
 368         if (ret < 0)
 369                 goto error_do_abort;
 370
 371         if (call->send_pages) {
 372                 ret = afs_send_pages(call, &msg, iov);
 373                 if (ret < 0)
 374                         goto error_do_abort;
 375         }
 376
 377         /* at this point, an async call may no longer exist as it may have
 378          * already completed */
 379         return wait_mode->wait(call);
 380
 381 error_do_abort:
 382         rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 383         rxrpc_kernel_end_call(rxcall);
 384         call->rxcall = NULL;
 385 error_kill_call:
 386         call->type->destructor(call);
 387         afs_free_call(call);
 388         _leave(" = %d", ret);
 389         return ret;
 390 }
 391
 392 /*
 393  * handles intercepted messages that were arriving in the socket's Rx queue
 394  * - called with the socket receive queue lock held to ensure message ordering
 395  * - called with softirqs disabled
 396  */
 397 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
 398                                struct sk_buff *skb)
 399 {
 400         struct afs_call *call = (struct afs_call *) user_call_ID;
 401
 402         _enter("%p,,%u", call, skb->mark);
 403
 404         _debug("ICPT %p{%u} [%d]",
 405                skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 406
 407         ASSERTCMP(sk, ==, afs_socket->sk);
 408         atomic_inc(&afs_outstanding_skbs);
 409
 410         if (!call) {
 411                 /* its an incoming call for our callback service */
 412                 skb_queue_tail(&afs_incoming_calls, skb);
 413                 schedule_work(&afs_collect_incoming_call_work);
 414         } else {
 415                 /* route the messages directly to the appropriate call */
 416                 skb_queue_tail(&call->rx_queue, skb);
 417                 call->wait_mode->rx_wakeup(call);
 418         }
 419
 420         _leave("");
 421 }
 422
 423 /*
 424  * deliver messages to a call
 425  */
 426 static void afs_deliver_to_call(struct afs_call *call)
 427 {
 428         struct sk_buff *skb;
 429         bool last;
 430         u32 abort_code;
 431         int ret;
 432
 433         _enter("");
 434
 435         while ((call->state == AFS_CALL_AWAIT_REPLY ||
 436                 call->state == AFS_CALL_AWAIT_OP_ID ||
 437                 call->state == AFS_CALL_AWAIT_REQUEST ||
 438                 call->state == AFS_CALL_AWAIT_ACK) &&
 439                (skb = skb_dequeue(&call->rx_queue))) {
 440                 switch (skb->mark) {
 441                 case RXRPC_SKB_MARK_DATA:
 442                         _debug("Rcv DATA");
 443                         last = rxrpc_kernel_is_data_last(skb);
 444                         ret = call->type->deliver(call, skb, last);
 445                         switch (ret) {
 446                         case 0:
 447                                 if (last &&
 448                                     call->state == AFS_CALL_AWAIT_REPLY)
 449                                         call->state = AFS_CALL_COMPLETE;
 450                                 break;
 451                         case -ENOTCONN:
 452                                 abort_code = RX_CALL_DEAD;
 453                                 goto do_abort;
 454                         case -ENOTSUPP:
 455                                 abort_code = RX_INVALID_OPERATION;
 456                                 goto do_abort;
 457                         default:
 458                                 abort_code = RXGEN_CC_UNMARSHAL;
 459                                 if (call->state != AFS_CALL_AWAIT_REPLY)
 460                                         abort_code = RXGEN_SS_UNMARSHAL;
 461                         do_abort:
 462                                 rxrpc_kernel_abort_call(call->rxcall,
 463                                                         abort_code);
 464                                 call->error = ret;
 465                                 call->state = AFS_CALL_ERROR;
 466                                 break;
 467                         }
 468                         afs_data_delivered(skb);
 469                         skb = NULL;
 470                         continue;
 471                 case RXRPC_SKB_MARK_FINAL_ACK:
 472                         _debug("Rcv ACK");
 473                         call->state = AFS_CALL_COMPLETE;
 474                         break;
 475                 case RXRPC_SKB_MARK_BUSY:
 476                         _debug("Rcv BUSY");
 477                         call->error = -EBUSY;
 478                         call->state = AFS_CALL_BUSY;
 479                         break;
 480                 case RXRPC_SKB_MARK_REMOTE_ABORT:
 481                         abort_code = rxrpc_kernel_get_abort_code(skb);
 482                         call->error = call->type->abort_to_error(abort_code);
 483                         call->state = AFS_CALL_ABORTED;
 484                         _debug("Rcv ABORT %u -> %d", abort_code, call->error);
 485                         break;
 486                 case RXRPC_SKB_MARK_NET_ERROR:
 487                         call->error = -rxrpc_kernel_get_error_number(skb);
 488                         call->state = AFS_CALL_ERROR;
 489                         _debug("Rcv NET ERROR %d", call->error);
 490                         break;
 491                 case RXRPC_SKB_MARK_LOCAL_ERROR:
 492                         call->error = -rxrpc_kernel_get_error_number(skb);
 493                         call->state = AFS_CALL_ERROR;
 494                         _debug("Rcv LOCAL ERROR %d", call->error);
 495                         break;
 496                 default:
 497                         BUG();
 498                         break;
 499                 }
 500
 501                 afs_free_skb(skb);
 502         }
 503
 504         /* make sure the queue is empty if the call is done with (we might have
 505          * aborted the call early because of an unmarshalling error) */
 506         if (call->state >= AFS_CALL_COMPLETE) {
 507                 while ((skb = skb_dequeue(&call->rx_queue)))
 508                         afs_free_skb(skb);
 509                 if (call->incoming) {
 510                         rxrpc_kernel_end_call(call->rxcall);
 511                         call->rxcall = NULL;
 512                         call->type->destructor(call);
 513                         afs_free_call(call);
 514                 }
 515         }
 516
 517         _leave("");
 518 }
 519
 520 /*
 521  * wait synchronously for a call to complete
 522  */
 523 static int afs_wait_for_call_to_complete(struct afs_call *call)
 524 {
 525         struct sk_buff *skb;
 526         int ret;
 527
 528         DECLARE_WAITQUEUE(myself, current);
 529
 530         _enter("");
 531
 532         add_wait_queue(&call->waitq, &myself);
 533         for (;;) {
 534                 set_current_state(TASK_INTERRUPTIBLE);
 535
 536                 /* deliver any messages that are in the queue */
 537                 if (!skb_queue_empty(&call->rx_queue)) {
 538                         __set_current_state(TASK_RUNNING);
 539                         afs_deliver_to_call(call);
 540                         continue;
 541                 }
 542
 543                 ret = call->error;
 544                 if (call->state >= AFS_CALL_COMPLETE)
 545                         break;
 546                 ret = -EINTR;
 547                 if (signal_pending(current))
 548                         break;
 549                 schedule();
 550         }
 551
 552         remove_wait_queue(&call->waitq, &myself);
 553         __set_current_state(TASK_RUNNING);
 554
 555         /* kill the call */
 556         if (call->state < AFS_CALL_COMPLETE) {
 557                 _debug("call incomplete");
 558                 rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
 559                 while ((skb = skb_dequeue(&call->rx_queue)))
 560                         afs_free_skb(skb);
 561         }
 562
 563         _debug("call complete");
 564         rxrpc_kernel_end_call(call->rxcall);
 565         call->rxcall = NULL;
 566         call->type->destructor(call);
 567         afs_free_call(call);
 568         _leave(" = %d", ret);
 569         return ret;
 570 }
 571
 572 /*
 573  * wake up a waiting call
 574  */
 575 static void afs_wake_up_call_waiter(struct afs_call *call)
 576 {
 577         wake_up(&call->waitq);
 578 }
 579
 580 /*
 581  * wake up an asynchronous call
 582  */
 583 static void afs_wake_up_async_call(struct afs_call *call)
 584 {
 585         _enter("");
 586         queue_work(afs_async_calls, &call->async_work);
 587 }
 588
 589 /*
 590  * put a call into asynchronous mode
 591  * - mustn't touch the call descriptor as the call my have completed by the
 592  *   time we get here
 593  */
 594 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
 595 {
 596         _enter("");
 597         return -EINPROGRESS;
 598 }
 599
 600 /*
 601  * delete an asynchronous call
 602  */
 603 static void afs_delete_async_call(struct work_struct *work)
 604 {
 605         struct afs_call *call =
 606                 container_of(work, struct afs_call, async_work);
 607
 608         _enter("");
 609
 610         afs_free_call(call);
 611
 612         _leave("");
 613 }
 614
 615 /*
 616  * perform processing on an asynchronous call
 617  * - on a multiple-thread workqueue this work item may try to run on several
 618  *   CPUs at the same time
 619  */
 620 static void afs_process_async_call(struct work_struct *work)
 621 {
 622         struct afs_call *call =
 623                 container_of(work, struct afs_call, async_work);
 624
 625         _enter("");
 626
 627         if (!skb_queue_empty(&call->rx_queue))
 628                 afs_deliver_to_call(call);
 629
 630         if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
 631                 if (call->wait_mode->async_complete)
 632                         call->wait_mode->async_complete(call->reply,
 633                                                         call->error);
 634                 call->reply = NULL;
 635
 636                 /* kill the call */
 637                 rxrpc_kernel_end_call(call->rxcall);
 638                 call->rxcall = NULL;
 639                 if (call->type->destructor)
 640                         call->type->destructor(call);
 641
 642                 /* we can't just delete the call because the work item may be
 643                  * queued */
 644                 PREPARE_WORK(&call->async_work, afs_delete_async_call);
 645                 queue_work(afs_async_calls, &call->async_work);
 646         }
 647
 648         _leave("");
 649 }
 650
 651 /*
 652  * empty a socket buffer into a flat reply buffer
 653  */
 654 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
 655 {
 656         size_t len = skb->len;
 657
 658         if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
 659                 BUG();
 660         call->reply_size += len;
 661 }
 662
 663 /*
 664  * accept the backlog of incoming calls
 665  */
 666 static void afs_collect_incoming_call(struct work_struct *work)
 667 {
 668         struct rxrpc_call *rxcall;
 669         struct afs_call *call = NULL;
 670         struct sk_buff *skb;
 671
 672         while ((skb = skb_dequeue(&afs_incoming_calls))) {
 673                 _debug("new call");
 674
 675                 /* don't need the notification */
 676                 afs_free_skb(skb);
 677
 678                 if (!call) {
 679                         call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
 680                         if (!call) {
 681                                 rxrpc_kernel_reject_call(afs_socket);
 682                                 return;
 683                         }
 684
 685                         INIT_WORK(&call->async_work, afs_process_async_call);
 686                         call->wait_mode = &afs_async_incoming_call;
 687                         call->type = &afs_RXCMxxxx;
 688                         init_waitqueue_head(&call->waitq);
 689                         skb_queue_head_init(&call->rx_queue);
 690                         call->state = AFS_CALL_AWAIT_OP_ID;
 691
 692                         _debug("CALL %p{%s} [%d]",
 693                                call, call->type->name,
 694                                atomic_read(&afs_outstanding_calls));
 695                         atomic_inc(&afs_outstanding_calls);
 696                 }
 697
 698                 rxcall = rxrpc_kernel_accept_call(afs_socket,
 699                                                   (unsigned long) call);
 700                 if (!IS_ERR(rxcall)) {
 701                         call->rxcall = rxcall;
 702                         call = NULL;
 703                 }
 704         }
 705
 706         if (call)
 707                 afs_free_call(call);
 708 }
 709
 710 /*
 711  * grab the operation ID from an incoming cache manager call
 712  */
 713 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 714                                 bool last)
 715 {
 716         size_t len = skb->len;
 717         void *oibuf = (void *) &call->operation_ID;
 718
 719         _enter("{%u},{%zu},%d", call->offset, len, last);
 720
 721         ASSERTCMP(call->offset, <, 4);
 722
 723         /* the operation ID forms the first four bytes of the request data */
 724         len = min_t(size_t, len, 4 - call->offset);
 725         if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
 726                 BUG();
 727         if (!pskb_pull(skb, len))
 728                 BUG();
 729         call->offset += len;
 730
 731         if (call->offset < 4) {
 732                 if (last) {
 733                         _leave(" = -EBADMSG [op ID short]");
 734                         return -EBADMSG;
 735                 }
 736                 _leave(" = 0 [incomplete]");
 737                 return 0;
 738         }
 739
 740         call->state = AFS_CALL_AWAIT_REQUEST;
 741
 742         /* ask the cache manager to route the call (it'll change the call type
 743          * if successful) */
 744         if (!afs_cm_incoming_call(call))
 745                 return -ENOTSUPP;
 746
 747         /* pass responsibility for the remainer of this message off to the
 748          * cache manager op */
 749         return call->type->deliver(call, skb, last);
 750 }
 751
 752 /*
 753  * send an empty reply
 754  */
 755 void afs_send_empty_reply(struct afs_call *call)
 756 {
 757         struct msghdr msg;
 758         struct iovec iov[1];
 759
 760         _enter("");
 761
 762         iov[0].iov_base         = NULL;
 763         iov[0].iov_len          = 0;
 764         msg.msg_name            = NULL;
 765         msg.msg_namelen         = 0;
 766         msg.msg_iov             = iov;
 767         msg.msg_iovlen          = 0;
 768         msg.msg_control         = NULL;
 769         msg.msg_controllen      = 0;
 770         msg.msg_flags           = 0;
 771
 772         call->state = AFS_CALL_AWAIT_ACK;
 773         switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
 774         case 0:
 775                 _leave(" [replied]");
 776                 return;
 777
 778         case -ENOMEM:
 779                 _debug("oom");
 780                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 781         default:
 782                 rxrpc_kernel_end_call(call->rxcall);
 783                 call->rxcall = NULL;
 784                 call->type->destructor(call);
 785                 afs_free_call(call);
 786                 _leave(" [error]");
 787                 return;
 788         }
 789 }
 790
 791 /*
 792  * send a simple reply
 793  */
 794 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 795 {
 796         struct msghdr msg;
 797         struct iovec iov[1];
 798         int n;
 799
 800         _enter("");
 801
 802         iov[0].iov_base         = (void *) buf;
 803         iov[0].iov_len          = len;
 804         msg.msg_name            = NULL;
 805         msg.msg_namelen         = 0;
 806         msg.msg_iov             = iov;
 807         msg.msg_iovlen          = 1;
 808         msg.msg_control         = NULL;
 809         msg.msg_controllen      = 0;
 810         msg.msg_flags           = 0;
 811
 812         call->state = AFS_CALL_AWAIT_ACK;
 813         n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
 814         if (n >= 0) {
 815                 _leave(" [replied]");
 816                 return;
 817         }
 818         if (n == -ENOMEM) {
 819                 _debug("oom");
 820                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 821         }
 822         rxrpc_kernel_end_call(call->rxcall);
 823         call->rxcall = NULL;
 824         call->type->destructor(call);
 825         afs_free_call(call);
 826         _leave(" [error]");
 827 }
 828
 829 /*
 830  * extract a piece of data from the received data socket buffers
 831  */
 832 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 833                      bool last, void *buf, size_t count)
 834 {
 835         size_t len = skb->len;
 836
 837         _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
 838
 839         ASSERTCMP(call->offset, <, count);
 840
 841         len = min_t(size_t, len, count - call->offset);
 842         if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
 843             !pskb_pull(skb, len))
 844                 BUG();
 845         call->offset += len;
 846
 847         if (call->offset < count) {
 848                 if (last) {
 849                         _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
 850                         return -EBADMSG;
 851                 }
 852                 _leave(" = -EAGAIN");
 853                 return -EAGAIN;
 854         }
 855         return 0;
 856 }