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        struct sk_buff *skb;
 318
 319        _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 320
 321        ASSERT(call->type != NULL);
 322        ASSERT(call->type->name != NULL);
 323
 324        _debug("____MAKE %p{%s,%x} [%d]____",
 325               call, call->type->name, key_serial(call->key),
 326               atomic_read(&afs_outstanding_calls));
 327
 328        call->wait_mode = wait_mode;
 329        INIT_WORK(&call->async_work, afs_process_async_call);
 330
 331        memset(&srx, 0, sizeof(srx));
 332        srx.srx_family = AF_RXRPC;
 333        srx.srx_service = call->service_id;
 334        srx.transport_type = SOCK_DGRAM;
 335        srx.transport_len = sizeof(srx.transport.sin);
 336        srx.transport.sin.sin_family = AF_INET;
 337        srx.transport.sin.sin_port = call->port;
 338        memcpy(&srx.transport.sin.sin_addr, addr, 4);
 339
 340        /* create a call */
 341        rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 342                                         (unsigned long) call, gfp);
 343        call->key = NULL;
 344        if (IS_ERR(rxcall)) {
 345                ret = PTR_ERR(rxcall);
 346                goto error_kill_call;
 347        }
 348
 349        call->rxcall = rxcall;
 350
 351        /* send the request */
 352        iov[0].iov_base = call->request;
 353        iov[0].iov_len  = call->request_size;
 354
 355        msg.msg_name            = NULL;
 356        msg.msg_namelen         = 0;
 357        msg.msg_iov             = (struct iovec *) iov;
 358        msg.msg_iovlen          = 1;
 359        msg.msg_control         = NULL;
 360        msg.msg_controllen      = 0;
 361        msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
 362
 363        /* have to change the state *before* sending the last packet as RxRPC
 364         * might give us the reply before it returns from sending the
 365         * request */
 366        if (!call->send_pages)
 367                call->state = AFS_CALL_AWAIT_REPLY;
 368        ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
 369        if (ret < 0)
 370                goto error_do_abort;
 371
 372        if (call->send_pages) {
 373                ret = afs_send_pages(call, &msg, iov);
 374                if (ret < 0)
 375                        goto error_do_abort;
 376        }
 377
 378        /* at this point, an async call may no longer exist as it may have
 379         * already completed */
 380        return wait_mode->wait(call);
 381
 382error_do_abort:
 383        rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 384        while ((skb = skb_dequeue(&call->rx_queue)))
 385                afs_free_skb(skb);
 386        rxrpc_kernel_end_call(rxcall);
 387        call->rxcall = NULL;
 388error_kill_call:
 389        call->type->destructor(call);
 390        afs_free_call(call);
 391        _leave(" = %d", ret);
 392        return ret;
 393}
 394
 395/*
 396 * handles intercepted messages that were arriving in the socket's Rx queue
 397 * - called with the socket receive queue lock held to ensure message ordering
 398 * - called with softirqs disabled
 399 */
 400static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
 401                               struct sk_buff *skb)
 402{
 403        struct afs_call *call = (struct afs_call *) user_call_ID;
 404
 405        _enter("%p,,%u", call, skb->mark);
 406
 407        _debug("ICPT %p{%u} [%d]",
 408               skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 409
 410        ASSERTCMP(sk, ==, afs_socket->sk);
 411        atomic_inc(&afs_outstanding_skbs);
 412
 413        if (!call) {
 414                /* its an incoming call for our callback service */
 415                skb_queue_tail(&afs_incoming_calls, skb);
 416                queue_work(afs_wq, &afs_collect_incoming_call_work);
 417        } else {
 418                /* route the messages directly to the appropriate call */
 419                skb_queue_tail(&call->rx_queue, skb);
 420                call->wait_mode->rx_wakeup(call);
 421        }
 422
 423        _leave("");
 424}
 425
 426/*
 427 * deliver messages to a call
 428 */
 429static void afs_deliver_to_call(struct afs_call *call)
 430{
 431        struct sk_buff *skb;
 432        bool last;
 433        u32 abort_code;
 434        int ret;
 435
 436        _enter("");
 437
 438        while ((call->state == AFS_CALL_AWAIT_REPLY ||
 439                call->state == AFS_CALL_AWAIT_OP_ID ||
 440                call->state == AFS_CALL_AWAIT_REQUEST ||
 441                call->state == AFS_CALL_AWAIT_ACK) &&
 442               (skb = skb_dequeue(&call->rx_queue))) {
 443                switch (skb->mark) {
 444                case RXRPC_SKB_MARK_DATA:
 445                        _debug("Rcv DATA");
 446                        last = rxrpc_kernel_is_data_last(skb);
 447                        ret = call->type->deliver(call, skb, last);
 448                        switch (ret) {
 449                        case 0:
 450                                if (last &&
 451                                    call->state == AFS_CALL_AWAIT_REPLY)
 452                                        call->state = AFS_CALL_COMPLETE;
 453                                break;
 454                        case -ENOTCONN:
 455                                abort_code = RX_CALL_DEAD;
 456                                goto do_abort;
 457                        case -ENOTSUPP:
 458                                abort_code = RX_INVALID_OPERATION;
 459                                goto do_abort;
 460                        default:
 461                                abort_code = RXGEN_CC_UNMARSHAL;
 462                                if (call->state != AFS_CALL_AWAIT_REPLY)
 463                                        abort_code = RXGEN_SS_UNMARSHAL;
 464                        do_abort:
 465                                rxrpc_kernel_abort_call(call->rxcall,
 466                                                        abort_code);
 467                                call->error = ret;
 468                                call->state = AFS_CALL_ERROR;
 469                                break;
 470                        }
 471                        afs_data_delivered(skb);
 472                        skb = NULL;
 473                        continue;
 474                case RXRPC_SKB_MARK_FINAL_ACK:
 475                        _debug("Rcv ACK");
 476                        call->state = AFS_CALL_COMPLETE;
 477                        break;
 478                case RXRPC_SKB_MARK_BUSY:
 479                        _debug("Rcv BUSY");
 480                        call->error = -EBUSY;
 481                        call->state = AFS_CALL_BUSY;
 482                        break;
 483                case RXRPC_SKB_MARK_REMOTE_ABORT:
 484                        abort_code = rxrpc_kernel_get_abort_code(skb);
 485                        call->error = call->type->abort_to_error(abort_code);
 486                        call->state = AFS_CALL_ABORTED;
 487                        _debug("Rcv ABORT %u -> %d", abort_code, call->error);
 488                        break;
 489                case RXRPC_SKB_MARK_NET_ERROR:
 490                        call->error = -rxrpc_kernel_get_error_number(skb);
 491                        call->state = AFS_CALL_ERROR;
 492                        _debug("Rcv NET ERROR %d", call->error);
 493                        break;
 494                case RXRPC_SKB_MARK_LOCAL_ERROR:
 495                        call->error = -rxrpc_kernel_get_error_number(skb);
 496                        call->state = AFS_CALL_ERROR;
 497                        _debug("Rcv LOCAL ERROR %d", call->error);
 498                        break;
 499                default:
 500                        BUG();
 501                        break;
 502                }
 503
 504                afs_free_skb(skb);
 505        }
 506
 507        /* make sure the queue is empty if the call is done with (we might have
 508         * aborted the call early because of an unmarshalling error) */
 509        if (call->state >= AFS_CALL_COMPLETE) {
 510                while ((skb = skb_dequeue(&call->rx_queue)))
 511                        afs_free_skb(skb);
 512                if (call->incoming) {
 513                        rxrpc_kernel_end_call(call->rxcall);
 514                        call->rxcall = NULL;
 515                        call->type->destructor(call);
 516                        afs_free_call(call);
 517                }
 518        }
 519
 520        _leave("");
 521}
 522
 523/*
 524 * wait synchronously for a call to complete
 525 */
 526static int afs_wait_for_call_to_complete(struct afs_call *call)
 527{
 528        struct sk_buff *skb;
 529        int ret;
 530
 531        DECLARE_WAITQUEUE(myself, current);
 532
 533        _enter("");
 534
 535        add_wait_queue(&call->waitq, &myself);
 536        for (;;) {
 537                set_current_state(TASK_INTERRUPTIBLE);
 538
 539                /* deliver any messages that are in the queue */
 540                if (!skb_queue_empty(&call->rx_queue)) {
 541                        __set_current_state(TASK_RUNNING);
 542                        afs_deliver_to_call(call);
 543                        continue;
 544                }
 545
 546                ret = call->error;
 547                if (call->state >= AFS_CALL_COMPLETE)
 548                        break;
 549                ret = -EINTR;
 550                if (signal_pending(current))
 551                        break;
 552                schedule();
 553        }
 554
 555        remove_wait_queue(&call->waitq, &myself);
 556        __set_current_state(TASK_RUNNING);
 557
 558        /* kill the call */
 559        if (call->state < AFS_CALL_COMPLETE) {
 560                _debug("call incomplete");
 561                rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
 562                while ((skb = skb_dequeue(&call->rx_queue)))
 563                        afs_free_skb(skb);
 564        }
 565
 566        _debug("call complete");
 567        rxrpc_kernel_end_call(call->rxcall);
 568        call->rxcall = NULL;
 569        call->type->destructor(call);
 570        afs_free_call(call);
 571        _leave(" = %d", ret);
 572        return ret;
 573}
 574
 575/*
 576 * wake up a waiting call
 577 */
 578static void afs_wake_up_call_waiter(struct afs_call *call)
 579{
 580        wake_up(&call->waitq);
 581}
 582
 583/*
 584 * wake up an asynchronous call
 585 */
 586static void afs_wake_up_async_call(struct afs_call *call)
 587{
 588        _enter("");
 589        queue_work(afs_async_calls, &call->async_work);
 590}
 591
 592/*
 593 * put a call into asynchronous mode
 594 * - mustn't touch the call descriptor as the call my have completed by the
 595 *   time we get here
 596 */
 597static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
 598{
 599        _enter("");
 600        return -EINPROGRESS;
 601}
 602
 603/*
 604 * delete an asynchronous call
 605 */
 606static void afs_delete_async_call(struct work_struct *work)
 607{
 608        struct afs_call *call =
 609                container_of(work, struct afs_call, async_work);
 610
 611        _enter("");
 612
 613        afs_free_call(call);
 614
 615        _leave("");
 616}
 617
 618/*
 619 * perform processing on an asynchronous call
 620 * - on a multiple-thread workqueue this work item may try to run on several
 621 *   CPUs at the same time
 622 */
 623static void afs_process_async_call(struct work_struct *work)
 624{
 625        struct afs_call *call =
 626                container_of(work, struct afs_call, async_work);
 627
 628        _enter("");
 629
 630        if (!skb_queue_empty(&call->rx_queue))
 631                afs_deliver_to_call(call);
 632
 633        if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
 634                if (call->wait_mode->async_complete)
 635                        call->wait_mode->async_complete(call->reply,
 636                                                        call->error);
 637                call->reply = NULL;
 638
 639                /* kill the call */
 640                rxrpc_kernel_end_call(call->rxcall);
 641                call->rxcall = NULL;
 642                if (call->type->destructor)
 643                        call->type->destructor(call);
 644
 645                /* we can't just delete the call because the work item may be
 646                 * queued */
 647                PREPARE_WORK(&call->async_work, afs_delete_async_call);
 648                queue_work(afs_async_calls, &call->async_work);
 649        }
 650
 651        _leave("");
 652}
 653
 654/*
 655 * empty a socket buffer into a flat reply buffer
 656 */
 657void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
 658{
 659        size_t len = skb->len;
 660
 661        if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
 662                BUG();
 663        call->reply_size += len;
 664}
 665
 666/*
 667 * accept the backlog of incoming calls
 668 */
 669static void afs_collect_incoming_call(struct work_struct *work)
 670{
 671        struct rxrpc_call *rxcall;
 672        struct afs_call *call = NULL;
 673        struct sk_buff *skb;
 674
 675        while ((skb = skb_dequeue(&afs_incoming_calls))) {
 676                _debug("new call");
 677
 678                /* don't need the notification */
 679                afs_free_skb(skb);
 680
 681                if (!call) {
 682                        call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
 683                        if (!call) {
 684                                rxrpc_kernel_reject_call(afs_socket);
 685                                return;
 686                        }
 687
 688                        INIT_WORK(&call->async_work, afs_process_async_call);
 689                        call->wait_mode = &afs_async_incoming_call;
 690                        call->type = &afs_RXCMxxxx;
 691                        init_waitqueue_head(&call->waitq);
 692                        skb_queue_head_init(&call->rx_queue);
 693                        call->state = AFS_CALL_AWAIT_OP_ID;
 694
 695                        _debug("CALL %p{%s} [%d]",
 696                               call, call->type->name,
 697                               atomic_read(&afs_outstanding_calls));
 698                        atomic_inc(&afs_outstanding_calls);
 699                }
 700
 701                rxcall = rxrpc_kernel_accept_call(afs_socket,
 702                                                  (unsigned long) call);
 703                if (!IS_ERR(rxcall)) {
 704                        call->rxcall = rxcall;
 705                        call = NULL;
 706                }
 707        }
 708
 709        if (call)
 710                afs_free_call(call);
 711}
 712
 713/*
 714 * grab the operation ID from an incoming cache manager call
 715 */
 716static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 717                                bool last)
 718{
 719        size_t len = skb->len;
 720        void *oibuf = (void *) &call->operation_ID;
 721
 722        _enter("{%u},{%zu},%d", call->offset, len, last);
 723
 724        ASSERTCMP(call->offset, <, 4);
 725
 726        /* the operation ID forms the first four bytes of the request data */
 727        len = min_t(size_t, len, 4 - call->offset);
 728        if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
 729                BUG();
 730        if (!pskb_pull(skb, len))
 731                BUG();
 732        call->offset += len;
 733
 734        if (call->offset < 4) {
 735                if (last) {
 736                        _leave(" = -EBADMSG [op ID short]");
 737                        return -EBADMSG;
 738                }
 739                _leave(" = 0 [incomplete]");
 740                return 0;
 741        }
 742
 743        call->state = AFS_CALL_AWAIT_REQUEST;
 744
 745        /* ask the cache manager to route the call (it'll change the call type
 746         * if successful) */
 747        if (!afs_cm_incoming_call(call))
 748                return -ENOTSUPP;
 749
 750        /* pass responsibility for the remainer of this message off to the
 751         * cache manager op */
 752        return call->type->deliver(call, skb, last);
 753}
 754
 755/*
 756 * send an empty reply
 757 */
 758void afs_send_empty_reply(struct afs_call *call)
 759{
 760        struct msghdr msg;
 761        struct iovec iov[1];
 762
 763        _enter("");
 764
 765        iov[0].iov_base         = NULL;
 766        iov[0].iov_len          = 0;
 767        msg.msg_name            = NULL;
 768        msg.msg_namelen         = 0;
 769        msg.msg_iov             = iov;
 770        msg.msg_iovlen          = 0;
 771        msg.msg_control         = NULL;
 772        msg.msg_controllen      = 0;
 773        msg.msg_flags           = 0;
 774
 775        call->state = AFS_CALL_AWAIT_ACK;
 776        switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
 777        case 0:
 778                _leave(" [replied]");
 779                return;
 780
 781        case -ENOMEM:
 782                _debug("oom");
 783                rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 784        default:
 785                rxrpc_kernel_end_call(call->rxcall);
 786                call->rxcall = NULL;
 787                call->type->destructor(call);
 788                afs_free_call(call);
 789                _leave(" [error]");
 790                return;
 791        }
 792}
 793
 794/*
 795 * send a simple reply
 796 */
 797void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 798{
 799        struct msghdr msg;
 800        struct iovec iov[1];
 801        int n;
 802
 803        _enter("");
 804
 805        iov[0].iov_base         = (void *) buf;
 806        iov[0].iov_len          = len;
 807        msg.msg_name            = NULL;
 808        msg.msg_namelen         = 0;
 809        msg.msg_iov             = iov;
 810        msg.msg_iovlen          = 1;
 811        msg.msg_control         = NULL;
 812        msg.msg_controllen      = 0;
 813        msg.msg_flags           = 0;
 814
 815        call->state = AFS_CALL_AWAIT_ACK;
 816        n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
 817        if (n >= 0) {
 818                _leave(" [replied]");
 819                return;
 820        }
 821        if (n == -ENOMEM) {
 822                _debug("oom");
 823                rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 824        }
 825        rxrpc_kernel_end_call(call->rxcall);
 826        call->rxcall = NULL;
 827        call->type->destructor(call);
 828        afs_free_call(call);
 829        _leave(" [error]");
 830}
 831
 832/*
 833 * extract a piece of data from the received data socket buffers
 834 */
 835int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 836                     bool last, void *buf, size_t count)
 837{
 838        size_t len = skb->len;
 839
 840        _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
 841
 842        ASSERTCMP(call->offset, <, count);
 843
 844        len = min_t(size_t, len, count - call->offset);
 845        if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
 846            !pskb_pull(skb, len))
 847                BUG();
 848        call->offset += len;
 849
 850        if (call->offset < count) {
 851                if (last) {
 852                        _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
 853                        return -EBADMSG;
 854                }
 855                _leave(" = -EAGAIN");
 856                return -EAGAIN;
 857        }
 858        return 0;
 859}
 860
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