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  * attach the data from a bunch of pages on an inode to a call
 241  */
 242 static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
 243                           struct kvec *iov)
 244 {
 245         struct page *pages[8];
 246         unsigned count, n, loop, offset, to;
 247         pgoff_t first = call->first, last = call->last;
 248         int ret;
 249
 250         _enter("");
 251
 252         offset = call->first_offset;
 253         call->first_offset = 0;
 254
 255         do {
 256                 _debug("attach %lx-%lx", first, last);
 257
 258                 count = last - first + 1;
 259                 if (count > ARRAY_SIZE(pages))
 260                         count = ARRAY_SIZE(pages);
 261                 n = find_get_pages_contig(call->mapping, first, count, pages);
 262                 ASSERTCMP(n, ==, count);
 263
 264                 loop = 0;
 265                 do {
 266                         msg->msg_flags = 0;
 267                         to = PAGE_SIZE;
 268                         if (first + loop >= last)
 269                                 to = call->last_to;
 270                         else
 271                                 msg->msg_flags = MSG_MORE;
 272                         iov->iov_base = kmap(pages[loop]) + offset;
 273                         iov->iov_len = to - offset;
 274                         offset = 0;
 275
 276                         _debug("- range %u-%u%s",
 277                                offset, to, msg->msg_flags ? " [more]" : "");
 278                         msg->msg_iov = (struct iovec *) iov;
 279                         msg->msg_iovlen = 1;
 280
 281                         /* have to change the state *before* sending the last
 282                          * packet as RxRPC might give us the reply before it
 283                          * returns from sending the request */
 284                         if (first + loop >= last)
 285                                 call->state = AFS_CALL_AWAIT_REPLY;
 286                         ret = rxrpc_kernel_send_data(call->rxcall, msg,
 287                                                      to - offset);
 288                         kunmap(pages[loop]);
 289                         if (ret < 0)
 290                                 break;
 291                 } while (++loop < count);
 292                 first += count;
 293
 294                 for (loop = 0; loop < count; loop++)
 295                         put_page(pages[loop]);
 296                 if (ret < 0)
 297                         break;
 298         } while (first <= last);
 299
 300         _leave(" = %d", ret);
 301         return ret;
 302 }
 303
 304 /*
 305  * initiate a call
 306  */
 307 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 308                   const struct afs_wait_mode *wait_mode)
 309 {
 310         struct sockaddr_rxrpc srx;
 311         struct rxrpc_call *rxcall;
 312         struct msghdr msg;
 313         struct kvec iov[1];
 314         int ret;
 315
 316         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 317
 318         ASSERT(call->type != NULL);
 319         ASSERT(call->type->name != NULL);
 320
 321         _debug("____MAKE %p{%s,%x} [%d]____",
 322                call, call->type->name, key_serial(call->key),
 323                atomic_read(&afs_outstanding_calls));
 324
 325         call->wait_mode = wait_mode;
 326         INIT_WORK(&call->async_work, afs_process_async_call);
 327
 328         memset(&srx, 0, sizeof(srx));
 329         srx.srx_family = AF_RXRPC;
 330         srx.srx_service = call->service_id;
 331         srx.transport_type = SOCK_DGRAM;
 332         srx.transport_len = sizeof(srx.transport.sin);
 333         srx.transport.sin.sin_family = AF_INET;
 334         srx.transport.sin.sin_port = call->port;
 335         memcpy(&srx.transport.sin.sin_addr, addr, 4);
 336
 337         /* create a call */
 338         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 339                                          (unsigned long) call, gfp);
 340         call->key = NULL;
 341         if (IS_ERR(rxcall)) {
 342                 ret = PTR_ERR(rxcall);
 343                 goto error_kill_call;
 344         }
 345
 346         call->rxcall = rxcall;
 347
 348         /* send the request */
 349         iov[0].iov_base = call->request;
 350         iov[0].iov_len  = call->request_size;
 351
 352         msg.msg_name            = NULL;
 353         msg.msg_namelen         = 0;
 354         msg.msg_iov             = (struct iovec *) iov;
 355         msg.msg_iovlen          = 1;
 356         msg.msg_control         = NULL;
 357         msg.msg_controllen      = 0;
 358         msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
 359
 360         /* have to change the state *before* sending the last packet as RxRPC
 361          * might give us the reply before it returns from sending the
 362          * request */
 363         if (!call->send_pages)
 364                 call->state = AFS_CALL_AWAIT_REPLY;
 365         ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
 366         if (ret < 0)
 367                 goto error_do_abort;
 368
 369         if (call->send_pages) {
 370                 ret = afs_send_pages(call, &msg, iov);
 371                 if (ret < 0)
 372                         goto error_do_abort;
 373         }
 374
 375         /* at this point, an async call may no longer exist as it may have
 376          * already completed */
 377         return wait_mode->wait(call);
 378
 379 error_do_abort:
 380         rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 381         rxrpc_kernel_end_call(rxcall);
 382         call->rxcall = NULL;
 383 error_kill_call:
 384         call->type->destructor(call);
 385         afs_free_call(call);
 386         _leave(" = %d", ret);
 387         return ret;
 388 }
 389
 390 /*
 391  * handles intercepted messages that were arriving in the socket's Rx queue
 392  * - called with the socket receive queue lock held to ensure message ordering
 393  * - called with softirqs disabled
 394  */
 395 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
 396                                struct sk_buff *skb)
 397 {
 398         struct afs_call *call = (struct afs_call *) user_call_ID;
 399
 400         _enter("%p,,%u", call, skb->mark);
 401
 402         _debug("ICPT %p{%u} [%d]",
 403                skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 404
 405         ASSERTCMP(sk, ==, afs_socket->sk);
 406         atomic_inc(&afs_outstanding_skbs);
 407
 408         if (!call) {
 409                 /* its an incoming call for our callback service */
 410                 skb_queue_tail(&afs_incoming_calls, skb);
 411                 schedule_work(&afs_collect_incoming_call_work);
 412         } else {
 413                 /* route the messages directly to the appropriate call */
 414                 skb_queue_tail(&call->rx_queue, skb);
 415                 call->wait_mode->rx_wakeup(call);
 416         }
 417
 418         _leave("");
 419 }
 420
 421 /*
 422  * deliver messages to a call
 423  */
 424 static void afs_deliver_to_call(struct afs_call *call)
 425 {
 426         struct sk_buff *skb;
 427         bool last;
 428         u32 abort_code;
 429         int ret;
 430
 431         _enter("");
 432
 433         while ((call->state == AFS_CALL_AWAIT_REPLY ||
 434                 call->state == AFS_CALL_AWAIT_OP_ID ||
 435                 call->state == AFS_CALL_AWAIT_REQUEST ||
 436                 call->state == AFS_CALL_AWAIT_ACK) &&
 437                (skb = skb_dequeue(&call->rx_queue))) {
 438                 switch (skb->mark) {
 439                 case RXRPC_SKB_MARK_DATA:
 440                         _debug("Rcv DATA");
 441                         last = rxrpc_kernel_is_data_last(skb);
 442                         ret = call->type->deliver(call, skb, last);
 443                         switch (ret) {
 444                         case 0:
 445                                 if (last &&
 446                                     call->state == AFS_CALL_AWAIT_REPLY)
 447                                         call->state = AFS_CALL_COMPLETE;
 448                                 break;
 449                         case -ENOTCONN:
 450                                 abort_code = RX_CALL_DEAD;
 451                                 goto do_abort;
 452                         case -ENOTSUPP:
 453                                 abort_code = RX_INVALID_OPERATION;
 454                                 goto do_abort;
 455                         default:
 456                                 abort_code = RXGEN_CC_UNMARSHAL;
 457                                 if (call->state != AFS_CALL_AWAIT_REPLY)
 458                                         abort_code = RXGEN_SS_UNMARSHAL;
 459                         do_abort:
 460                                 rxrpc_kernel_abort_call(call->rxcall,
 461                                                         abort_code);
 462                                 call->error = ret;
 463                                 call->state = AFS_CALL_ERROR;
 464                                 break;
 465                         }
 466                         afs_data_delivered(skb);
 467                         skb = NULL;
 468                         continue;
 469                 case RXRPC_SKB_MARK_FINAL_ACK:
 470                         _debug("Rcv ACK");
 471                         call->state = AFS_CALL_COMPLETE;
 472                         break;
 473                 case RXRPC_SKB_MARK_BUSY:
 474                         _debug("Rcv BUSY");
 475                         call->error = -EBUSY;
 476                         call->state = AFS_CALL_BUSY;
 477                         break;
 478                 case RXRPC_SKB_MARK_REMOTE_ABORT:
 479                         abort_code = rxrpc_kernel_get_abort_code(skb);
 480                         call->error = call->type->abort_to_error(abort_code);
 481                         call->state = AFS_CALL_ABORTED;
 482                         _debug("Rcv ABORT %u -> %d", abort_code, call->error);
 483                         break;
 484                 case RXRPC_SKB_MARK_NET_ERROR:
 485                         call->error = -rxrpc_kernel_get_error_number(skb);
 486                         call->state = AFS_CALL_ERROR;
 487                         _debug("Rcv NET ERROR %d", call->error);
 488                         break;
 489                 case RXRPC_SKB_MARK_LOCAL_ERROR:
 490                         call->error = -rxrpc_kernel_get_error_number(skb);
 491                         call->state = AFS_CALL_ERROR;
 492                         _debug("Rcv LOCAL ERROR %d", call->error);
 493                         break;
 494                 default:
 495                         BUG();
 496                         break;
 497                 }
 498
 499                 afs_free_skb(skb);
 500         }
 501
 502         /* make sure the queue is empty if the call is done with (we might have
 503          * aborted the call early because of an unmarshalling error) */
 504         if (call->state >= AFS_CALL_COMPLETE) {
 505                 while ((skb = skb_dequeue(&call->rx_queue)))
 506                         afs_free_skb(skb);
 507                 if (call->incoming) {
 508                         rxrpc_kernel_end_call(call->rxcall);
 509                         call->rxcall = NULL;
 510                         call->type->destructor(call);
 511                         afs_free_call(call);
 512                 }
 513         }
 514
 515         _leave("");
 516 }
 517
 518 /*
 519  * wait synchronously for a call to complete
 520  */
 521 static int afs_wait_for_call_to_complete(struct afs_call *call)
 522 {
 523         struct sk_buff *skb;
 524         int ret;
 525
 526         DECLARE_WAITQUEUE(myself, current);
 527
 528         _enter("");
 529
 530         add_wait_queue(&call->waitq, &myself);
 531         for (;;) {
 532                 set_current_state(TASK_INTERRUPTIBLE);
 533
 534                 /* deliver any messages that are in the queue */
 535                 if (!skb_queue_empty(&call->rx_queue)) {
 536                         __set_current_state(TASK_RUNNING);
 537                         afs_deliver_to_call(call);
 538                         continue;
 539                 }
 540
 541                 ret = call->error;
 542                 if (call->state >= AFS_CALL_COMPLETE)
 543                         break;
 544                 ret = -EINTR;
 545                 if (signal_pending(current))
 546                         break;
 547                 schedule();
 548         }
 549
 550         remove_wait_queue(&call->waitq, &myself);
 551         __set_current_state(TASK_RUNNING);
 552
 553         /* kill the call */
 554         if (call->state < AFS_CALL_COMPLETE) {
 555                 _debug("call incomplete");
 556                 rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
 557                 while ((skb = skb_dequeue(&call->rx_queue)))
 558                         afs_free_skb(skb);
 559         }
 560
 561         _debug("call complete");
 562         rxrpc_kernel_end_call(call->rxcall);
 563         call->rxcall = NULL;
 564         call->type->destructor(call);
 565         afs_free_call(call);
 566         _leave(" = %d", ret);
 567         return ret;
 568 }
 569
 570 /*
 571  * wake up a waiting call
 572  */
 573 static void afs_wake_up_call_waiter(struct afs_call *call)
 574 {
 575         wake_up(&call->waitq);
 576 }
 577
 578 /*
 579  * wake up an asynchronous call
 580  */
 581 static void afs_wake_up_async_call(struct afs_call *call)
 582 {
 583         _enter("");
 584         queue_work(afs_async_calls, &call->async_work);
 585 }
 586
 587 /*
 588  * put a call into asynchronous mode
 589  * - mustn't touch the call descriptor as the call my have completed by the
 590  *   time we get here
 591  */
 592 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
 593 {
 594         _enter("");
 595         return -EINPROGRESS;
 596 }
 597
 598 /*
 599  * delete an asynchronous call
 600  */
 601 static void afs_delete_async_call(struct work_struct *work)
 602 {
 603         struct afs_call *call =
 604                 container_of(work, struct afs_call, async_work);
 605
 606         _enter("");
 607
 608         afs_free_call(call);
 609
 610         _leave("");
 611 }
 612
 613 /*
 614  * perform processing on an asynchronous call
 615  * - on a multiple-thread workqueue this work item may try to run on several
 616  *   CPUs at the same time
 617  */
 618 static void afs_process_async_call(struct work_struct *work)
 619 {
 620         struct afs_call *call =
 621                 container_of(work, struct afs_call, async_work);
 622
 623         _enter("");
 624
 625         if (!skb_queue_empty(&call->rx_queue))
 626                 afs_deliver_to_call(call);
 627
 628         if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
 629                 if (call->wait_mode->async_complete)
 630                         call->wait_mode->async_complete(call->reply,
 631                                                         call->error);
 632                 call->reply = NULL;
 633
 634                 /* kill the call */
 635                 rxrpc_kernel_end_call(call->rxcall);
 636                 call->rxcall = NULL;
 637                 if (call->type->destructor)
 638                         call->type->destructor(call);
 639
 640                 /* we can't just delete the call because the work item may be
 641                  * queued */
 642                 PREPARE_WORK(&call->async_work, afs_delete_async_call);
 643                 queue_work(afs_async_calls, &call->async_work);
 644         }
 645
 646         _leave("");
 647 }
 648
 649 /*
 650  * empty a socket buffer into a flat reply buffer
 651  */
 652 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
 653 {
 654         size_t len = skb->len;
 655
 656         if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
 657                 BUG();
 658         call->reply_size += len;
 659 }
 660
 661 /*
 662  * accept the backlog of incoming calls
 663  */
 664 static void afs_collect_incoming_call(struct work_struct *work)
 665 {
 666         struct rxrpc_call *rxcall;
 667         struct afs_call *call = NULL;
 668         struct sk_buff *skb;
 669
 670         while ((skb = skb_dequeue(&afs_incoming_calls))) {
 671                 _debug("new call");
 672
 673                 /* don't need the notification */
 674                 afs_free_skb(skb);
 675
 676                 if (!call) {
 677                         call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
 678                         if (!call) {
 679                                 rxrpc_kernel_reject_call(afs_socket);
 680                                 return;
 681                         }
 682
 683                         INIT_WORK(&call->async_work, afs_process_async_call);
 684                         call->wait_mode = &afs_async_incoming_call;
 685                         call->type = &afs_RXCMxxxx;
 686                         init_waitqueue_head(&call->waitq);
 687                         skb_queue_head_init(&call->rx_queue);
 688                         call->state = AFS_CALL_AWAIT_OP_ID;
 689
 690                         _debug("CALL %p{%s} [%d]",
 691                                call, call->type->name,
 692                                atomic_read(&afs_outstanding_calls));
 693                         atomic_inc(&afs_outstanding_calls);
 694                 }
 695
 696                 rxcall = rxrpc_kernel_accept_call(afs_socket,
 697                                                   (unsigned long) call);
 698                 if (!IS_ERR(rxcall)) {
 699                         call->rxcall = rxcall;
 700                         call = NULL;
 701                 }
 702         }
 703
 704         if (call)
 705                 afs_free_call(call);
 706 }
 707
 708 /*
 709  * grab the operation ID from an incoming cache manager call
 710  */
 711 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 712                                 bool last)
 713 {
 714         size_t len = skb->len;
 715         void *oibuf = (void *) &call->operation_ID;
 716
 717         _enter("{%u},{%zu},%d", call->offset, len, last);
 718
 719         ASSERTCMP(call->offset, <, 4);
 720
 721         /* the operation ID forms the first four bytes of the request data */
 722         len = min_t(size_t, len, 4 - call->offset);
 723         if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
 724                 BUG();
 725         if (!pskb_pull(skb, len))
 726                 BUG();
 727         call->offset += len;
 728
 729         if (call->offset < 4) {
 730                 if (last) {
 731                         _leave(" = -EBADMSG [op ID short]");
 732                         return -EBADMSG;
 733                 }
 734                 _leave(" = 0 [incomplete]");
 735                 return 0;
 736         }
 737
 738         call->state = AFS_CALL_AWAIT_REQUEST;
 739
 740         /* ask the cache manager to route the call (it'll change the call type
 741          * if successful) */
 742         if (!afs_cm_incoming_call(call))
 743                 return -ENOTSUPP;
 744
 745         /* pass responsibility for the remainer of this message off to the
 746          * cache manager op */
 747         return call->type->deliver(call, skb, last);
 748 }
 749
 750 /*
 751  * send an empty reply
 752  */
 753 void afs_send_empty_reply(struct afs_call *call)
 754 {
 755         struct msghdr msg;
 756         struct iovec iov[1];
 757
 758         _enter("");
 759
 760         iov[0].iov_base         = NULL;
 761         iov[0].iov_len          = 0;
 762         msg.msg_name            = NULL;
 763         msg.msg_namelen         = 0;
 764         msg.msg_iov             = iov;
 765         msg.msg_iovlen          = 0;
 766         msg.msg_control         = NULL;
 767         msg.msg_controllen      = 0;
 768         msg.msg_flags           = 0;
 769
 770         call->state = AFS_CALL_AWAIT_ACK;
 771         switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
 772         case 0:
 773                 _leave(" [replied]");
 774                 return;
 775
 776         case -ENOMEM:
 777                 _debug("oom");
 778                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 779         default:
 780                 rxrpc_kernel_end_call(call->rxcall);
 781                 call->rxcall = NULL;
 782                 call->type->destructor(call);
 783                 afs_free_call(call);
 784                 _leave(" [error]");
 785                 return;
 786         }
 787 }
 788
 789 /*
 790  * send a simple reply
 791  */
 792 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 793 {
 794         struct msghdr msg;
 795         struct iovec iov[1];
 796         int n;
 797
 798         _enter("");
 799
 800         iov[0].iov_base         = (void *) buf;
 801         iov[0].iov_len          = len;
 802         msg.msg_name            = NULL;
 803         msg.msg_namelen         = 0;
 804         msg.msg_iov             = iov;
 805         msg.msg_iovlen          = 1;
 806         msg.msg_control         = NULL;
 807         msg.msg_controllen      = 0;
 808         msg.msg_flags           = 0;
 809
 810         call->state = AFS_CALL_AWAIT_ACK;
 811         n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
 812         if (n >= 0) {
 813                 _leave(" [replied]");
 814                 return;
 815         }
 816         if (n == -ENOMEM) {
 817                 _debug("oom");
 818                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 819         }
 820         rxrpc_kernel_end_call(call->rxcall);
 821         call->rxcall = NULL;
 822         call->type->destructor(call);
 823         afs_free_call(call);
 824         _leave(" [error]");
 825 }
 826
 827 /*
 828  * extract a piece of data from the received data socket buffers
 829  */
 830 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 831                      bool last, void *buf, size_t count)
 832 {
 833         size_t len = skb->len;
 834
 835         _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
 836
 837         ASSERTCMP(call->offset, <, count);
 838
 839         len = min_t(size_t, len, count - call->offset);
 840         if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
 841             !pskb_pull(skb, len))
 842                 BUG();
 843         call->offset += len;
 844
 845         if (call->offset < count) {
 846                 if (last) {
 847                         _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
 848                         return -EBADMSG;
 849                 }
 850                 _leave(" = -EAGAIN");
 851                 return -EAGAIN;
 852         }
 853         return 0;
 854 }