linux/fs/afs/rxrpc.c
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   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
  19static struct socket *afs_socket; /* my RxRPC socket */
  20static struct workqueue_struct *afs_async_calls;
  21static atomic_t afs_outstanding_calls;
  22static atomic_t afs_outstanding_skbs;
  23
  24static void afs_wake_up_call_waiter(struct afs_call *);
  25static int afs_wait_for_call_to_complete(struct afs_call *);
  26static void afs_wake_up_async_call(struct afs_call *);
  27static int afs_dont_wait_for_call_to_complete(struct afs_call *);
  28static void afs_process_async_call(struct work_struct *);
  29static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
  30static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
  31
  32/* synchronous call management */
  33const 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 */
  39const 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 */
  45static 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 */
  50static 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
  56static void afs_collect_incoming_call(struct work_struct *);
  57
  58static struct sk_buff_head afs_incoming_calls;
  59static 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 */
  65int 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 */
 118void 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 */
 136static 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 */
 153static 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 */
 170static 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 */
 189struct 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
 222nomem_free:
 223        afs_free_call(call);
 224nomem_call:
 225        return NULL;
 226}
 227
 228/*
 229 * clean up a call with flat buffer
 230 */
 231void 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 */
 244static 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 */
 309int 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
 381error_do_abort:
 382        rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 383        rxrpc_kernel_end_call(rxcall);
 384        call->rxcall = NULL;
 385error_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 */
 397static 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                queue_work(afs_wq, &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 */
 426static 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 */
 523static 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 */
 575static 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 */
 583static 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 */
 594static 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 */
 603static 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 */
 620static 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 */
 654void 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 */
 666static 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 */
 713static 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 */
 755void 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 */
 794void 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 */
 832int 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}
 857