linux/net/caif/caif_socket.c
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   1/*
   2 * Copyright (C) ST-Ericsson AB 2010
   3 * Author:      Sjur Brendeland sjur.brandeland@stericsson.com
   4 * License terms: GNU General Public License (GPL) version 2
   5 */
   6
   7#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9#include <linux/fs.h>
  10#include <linux/init.h>
  11#include <linux/module.h>
  12#include <linux/sched.h>
  13#include <linux/spinlock.h>
  14#include <linux/mutex.h>
  15#include <linux/list.h>
  16#include <linux/wait.h>
  17#include <linux/poll.h>
  18#include <linux/tcp.h>
  19#include <linux/uaccess.h>
  20#include <linux/debugfs.h>
  21#include <linux/caif/caif_socket.h>
  22#include <linux/pkt_sched.h>
  23#include <net/sock.h>
  24#include <net/tcp_states.h>
  25#include <net/caif/caif_layer.h>
  26#include <net/caif/caif_dev.h>
  27#include <net/caif/cfpkt.h>
  28
  29MODULE_LICENSE("GPL");
  30MODULE_ALIAS_NETPROTO(AF_CAIF);
  31
  32/*
  33 * CAIF state is re-using the TCP socket states.
  34 * caif_states stored in sk_state reflect the state as reported by
  35 * the CAIF stack, while sk_socket->state is the state of the socket.
  36 */
  37enum caif_states {
  38        CAIF_CONNECTED          = TCP_ESTABLISHED,
  39        CAIF_CONNECTING = TCP_SYN_SENT,
  40        CAIF_DISCONNECTED       = TCP_CLOSE
  41};
  42
  43#define TX_FLOW_ON_BIT  1
  44#define RX_FLOW_ON_BIT  2
  45
  46struct caifsock {
  47        struct sock sk; /* must be first member */
  48        struct cflayer layer;
  49        u32 flow_state;
  50        struct caif_connect_request conn_req;
  51        struct mutex readlock;
  52        struct dentry *debugfs_socket_dir;
  53        int headroom, tailroom, maxframe;
  54};
  55
  56static int rx_flow_is_on(struct caifsock *cf_sk)
  57{
  58        return test_bit(RX_FLOW_ON_BIT,
  59                        (void *) &cf_sk->flow_state);
  60}
  61
  62static int tx_flow_is_on(struct caifsock *cf_sk)
  63{
  64        return test_bit(TX_FLOW_ON_BIT,
  65                        (void *) &cf_sk->flow_state);
  66}
  67
  68static void set_rx_flow_off(struct caifsock *cf_sk)
  69{
  70         clear_bit(RX_FLOW_ON_BIT,
  71                 (void *) &cf_sk->flow_state);
  72}
  73
  74static void set_rx_flow_on(struct caifsock *cf_sk)
  75{
  76         set_bit(RX_FLOW_ON_BIT,
  77                        (void *) &cf_sk->flow_state);
  78}
  79
  80static void set_tx_flow_off(struct caifsock *cf_sk)
  81{
  82         clear_bit(TX_FLOW_ON_BIT,
  83                (void *) &cf_sk->flow_state);
  84}
  85
  86static void set_tx_flow_on(struct caifsock *cf_sk)
  87{
  88         set_bit(TX_FLOW_ON_BIT,
  89                (void *) &cf_sk->flow_state);
  90}
  91
  92static void caif_read_lock(struct sock *sk)
  93{
  94        struct caifsock *cf_sk;
  95        cf_sk = container_of(sk, struct caifsock, sk);
  96        mutex_lock(&cf_sk->readlock);
  97}
  98
  99static void caif_read_unlock(struct sock *sk)
 100{
 101        struct caifsock *cf_sk;
 102        cf_sk = container_of(sk, struct caifsock, sk);
 103        mutex_unlock(&cf_sk->readlock);
 104}
 105
 106static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 107{
 108        /* A quarter of full buffer is used a low water mark */
 109        return cf_sk->sk.sk_rcvbuf / 4;
 110}
 111
 112static void caif_flow_ctrl(struct sock *sk, int mode)
 113{
 114        struct caifsock *cf_sk;
 115        cf_sk = container_of(sk, struct caifsock, sk);
 116        if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 117                cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 118}
 119
 120/*
 121 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 122 * not dropped, but CAIF is sending flow off instead.
 123 */
 124static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 125{
 126        int err;
 127        int skb_len;
 128        unsigned long flags;
 129        struct sk_buff_head *list = &sk->sk_receive_queue;
 130        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 131
 132        if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 133                (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 134                net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 135                                    atomic_read(&cf_sk->sk.sk_rmem_alloc),
 136                                    sk_rcvbuf_lowwater(cf_sk));
 137                set_rx_flow_off(cf_sk);
 138                caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 139        }
 140
 141        err = sk_filter(sk, skb);
 142        if (err)
 143                return err;
 144        if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 145                set_rx_flow_off(cf_sk);
 146                net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 147                caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 148        }
 149        skb->dev = NULL;
 150        skb_set_owner_r(skb, sk);
 151        /* Cache the SKB length before we tack it onto the receive
 152         * queue. Once it is added it no longer belongs to us and
 153         * may be freed by other threads of control pulling packets
 154         * from the queue.
 155         */
 156        skb_len = skb->len;
 157        spin_lock_irqsave(&list->lock, flags);
 158        if (!sock_flag(sk, SOCK_DEAD))
 159                __skb_queue_tail(list, skb);
 160        spin_unlock_irqrestore(&list->lock, flags);
 161
 162        if (!sock_flag(sk, SOCK_DEAD))
 163                sk->sk_data_ready(sk, skb_len);
 164        else
 165                kfree_skb(skb);
 166        return 0;
 167}
 168
 169/* Packet Receive Callback function called from CAIF Stack */
 170static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 171{
 172        struct caifsock *cf_sk;
 173        struct sk_buff *skb;
 174
 175        cf_sk = container_of(layr, struct caifsock, layer);
 176        skb = cfpkt_tonative(pkt);
 177
 178        if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 179                kfree_skb(skb);
 180                return 0;
 181        }
 182        caif_queue_rcv_skb(&cf_sk->sk, skb);
 183        return 0;
 184}
 185
 186static void cfsk_hold(struct cflayer *layr)
 187{
 188        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 189        sock_hold(&cf_sk->sk);
 190}
 191
 192static void cfsk_put(struct cflayer *layr)
 193{
 194        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 195        sock_put(&cf_sk->sk);
 196}
 197
 198/* Packet Control Callback function called from CAIF */
 199static void caif_ctrl_cb(struct cflayer *layr,
 200                                enum caif_ctrlcmd flow,
 201                                int phyid)
 202{
 203        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 204        switch (flow) {
 205        case CAIF_CTRLCMD_FLOW_ON_IND:
 206                /* OK from modem to start sending again */
 207                set_tx_flow_on(cf_sk);
 208                cf_sk->sk.sk_state_change(&cf_sk->sk);
 209                break;
 210
 211        case CAIF_CTRLCMD_FLOW_OFF_IND:
 212                /* Modem asks us to shut up */
 213                set_tx_flow_off(cf_sk);
 214                cf_sk->sk.sk_state_change(&cf_sk->sk);
 215                break;
 216
 217        case CAIF_CTRLCMD_INIT_RSP:
 218                /* We're now connected */
 219                caif_client_register_refcnt(&cf_sk->layer,
 220                                                cfsk_hold, cfsk_put);
 221                cf_sk->sk.sk_state = CAIF_CONNECTED;
 222                set_tx_flow_on(cf_sk);
 223                cf_sk->sk.sk_shutdown = 0;
 224                cf_sk->sk.sk_state_change(&cf_sk->sk);
 225                break;
 226
 227        case CAIF_CTRLCMD_DEINIT_RSP:
 228                /* We're now disconnected */
 229                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 230                cf_sk->sk.sk_state_change(&cf_sk->sk);
 231                break;
 232
 233        case CAIF_CTRLCMD_INIT_FAIL_RSP:
 234                /* Connect request failed */
 235                cf_sk->sk.sk_err = ECONNREFUSED;
 236                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 237                cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 238                /*
 239                 * Socket "standards" seems to require POLLOUT to
 240                 * be set at connect failure.
 241                 */
 242                set_tx_flow_on(cf_sk);
 243                cf_sk->sk.sk_state_change(&cf_sk->sk);
 244                break;
 245
 246        case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 247                /* Modem has closed this connection, or device is down. */
 248                cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 249                cf_sk->sk.sk_err = ECONNRESET;
 250                set_rx_flow_on(cf_sk);
 251                cf_sk->sk.sk_error_report(&cf_sk->sk);
 252                break;
 253
 254        default:
 255                pr_debug("Unexpected flow command %d\n", flow);
 256        }
 257}
 258
 259static void caif_check_flow_release(struct sock *sk)
 260{
 261        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 262
 263        if (rx_flow_is_on(cf_sk))
 264                return;
 265
 266        if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 267                        set_rx_flow_on(cf_sk);
 268                        caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 269        }
 270}
 271
 272/*
 273 * Copied from unix_dgram_recvmsg, but removed credit checks,
 274 * changed locking, address handling and added MSG_TRUNC.
 275 */
 276static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
 277                                struct msghdr *m, size_t len, int flags)
 278
 279{
 280        struct sock *sk = sock->sk;
 281        struct sk_buff *skb;
 282        int ret;
 283        int copylen;
 284
 285        ret = -EOPNOTSUPP;
 286        if (m->msg_flags&MSG_OOB)
 287                goto read_error;
 288
 289        skb = skb_recv_datagram(sk, flags, 0 , &ret);
 290        if (!skb)
 291                goto read_error;
 292        copylen = skb->len;
 293        if (len < copylen) {
 294                m->msg_flags |= MSG_TRUNC;
 295                copylen = len;
 296        }
 297
 298        ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
 299        if (ret)
 300                goto out_free;
 301
 302        ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 303out_free:
 304        skb_free_datagram(sk, skb);
 305        caif_check_flow_release(sk);
 306        return ret;
 307
 308read_error:
 309        return ret;
 310}
 311
 312
 313/* Copied from unix_stream_wait_data, identical except for lock call. */
 314static long caif_stream_data_wait(struct sock *sk, long timeo)
 315{
 316        DEFINE_WAIT(wait);
 317        lock_sock(sk);
 318
 319        for (;;) {
 320                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 321
 322                if (!skb_queue_empty(&sk->sk_receive_queue) ||
 323                        sk->sk_err ||
 324                        sk->sk_state != CAIF_CONNECTED ||
 325                        sock_flag(sk, SOCK_DEAD) ||
 326                        (sk->sk_shutdown & RCV_SHUTDOWN) ||
 327                        signal_pending(current) ||
 328                        !timeo)
 329                        break;
 330
 331                set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 332                release_sock(sk);
 333                timeo = schedule_timeout(timeo);
 334                lock_sock(sk);
 335                clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 336        }
 337
 338        finish_wait(sk_sleep(sk), &wait);
 339        release_sock(sk);
 340        return timeo;
 341}
 342
 343
 344/*
 345 * Copied from unix_stream_recvmsg, but removed credit checks,
 346 * changed locking calls, changed address handling.
 347 */
 348static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 349                                struct msghdr *msg, size_t size,
 350                                int flags)
 351{
 352        struct sock *sk = sock->sk;
 353        int copied = 0;
 354        int target;
 355        int err = 0;
 356        long timeo;
 357
 358        err = -EOPNOTSUPP;
 359        if (flags&MSG_OOB)
 360                goto out;
 361
 362        msg->msg_namelen = 0;
 363
 364        /*
 365         * Lock the socket to prevent queue disordering
 366         * while sleeps in memcpy_tomsg
 367         */
 368        err = -EAGAIN;
 369        if (sk->sk_state == CAIF_CONNECTING)
 370                goto out;
 371
 372        caif_read_lock(sk);
 373        target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 374        timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 375
 376        do {
 377                int chunk;
 378                struct sk_buff *skb;
 379
 380                lock_sock(sk);
 381                skb = skb_dequeue(&sk->sk_receive_queue);
 382                caif_check_flow_release(sk);
 383
 384                if (skb == NULL) {
 385                        if (copied >= target)
 386                                goto unlock;
 387                        /*
 388                         *      POSIX 1003.1g mandates this order.
 389                         */
 390                        err = sock_error(sk);
 391                        if (err)
 392                                goto unlock;
 393                        err = -ECONNRESET;
 394                        if (sk->sk_shutdown & RCV_SHUTDOWN)
 395                                goto unlock;
 396
 397                        err = -EPIPE;
 398                        if (sk->sk_state != CAIF_CONNECTED)
 399                                goto unlock;
 400                        if (sock_flag(sk, SOCK_DEAD))
 401                                goto unlock;
 402
 403                        release_sock(sk);
 404
 405                        err = -EAGAIN;
 406                        if (!timeo)
 407                                break;
 408
 409                        caif_read_unlock(sk);
 410
 411                        timeo = caif_stream_data_wait(sk, timeo);
 412
 413                        if (signal_pending(current)) {
 414                                err = sock_intr_errno(timeo);
 415                                goto out;
 416                        }
 417                        caif_read_lock(sk);
 418                        continue;
 419unlock:
 420                        release_sock(sk);
 421                        break;
 422                }
 423                release_sock(sk);
 424                chunk = min_t(unsigned int, skb->len, size);
 425                if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
 426                        skb_queue_head(&sk->sk_receive_queue, skb);
 427                        if (copied == 0)
 428                                copied = -EFAULT;
 429                        break;
 430                }
 431                copied += chunk;
 432                size -= chunk;
 433
 434                /* Mark read part of skb as used */
 435                if (!(flags & MSG_PEEK)) {
 436                        skb_pull(skb, chunk);
 437
 438                        /* put the skb back if we didn't use it up. */
 439                        if (skb->len) {
 440                                skb_queue_head(&sk->sk_receive_queue, skb);
 441                                break;
 442                        }
 443                        kfree_skb(skb);
 444
 445                } else {
 446                        /*
 447                         * It is questionable, see note in unix_dgram_recvmsg.
 448                         */
 449                        /* put message back and return */
 450                        skb_queue_head(&sk->sk_receive_queue, skb);
 451                        break;
 452                }
 453        } while (size);
 454        caif_read_unlock(sk);
 455
 456out:
 457        return copied ? : err;
 458}
 459
 460/*
 461 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 462 * CAIF flow-on and sock_writable.
 463 */
 464static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 465                                int wait_writeable, long timeo, int *err)
 466{
 467        struct sock *sk = &cf_sk->sk;
 468        DEFINE_WAIT(wait);
 469        for (;;) {
 470                *err = 0;
 471                if (tx_flow_is_on(cf_sk) &&
 472                        (!wait_writeable || sock_writeable(&cf_sk->sk)))
 473                        break;
 474                *err = -ETIMEDOUT;
 475                if (!timeo)
 476                        break;
 477                *err = -ERESTARTSYS;
 478                if (signal_pending(current))
 479                        break;
 480                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 481                *err = -ECONNRESET;
 482                if (sk->sk_shutdown & SHUTDOWN_MASK)
 483                        break;
 484                *err = -sk->sk_err;
 485                if (sk->sk_err)
 486                        break;
 487                *err = -EPIPE;
 488                if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 489                        break;
 490                timeo = schedule_timeout(timeo);
 491        }
 492        finish_wait(sk_sleep(sk), &wait);
 493        return timeo;
 494}
 495
 496/*
 497 * Transmit a SKB. The device may temporarily request re-transmission
 498 * by returning EAGAIN.
 499 */
 500static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 501                        int noblock, long timeo)
 502{
 503        struct cfpkt *pkt;
 504
 505        pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 506        memset(skb->cb, 0, sizeof(struct caif_payload_info));
 507        cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 508
 509        if (cf_sk->layer.dn == NULL) {
 510                kfree_skb(skb);
 511                return -EINVAL;
 512        }
 513
 514        return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 515}
 516
 517/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 518static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 519                        struct msghdr *msg, size_t len)
 520{
 521        struct sock *sk = sock->sk;
 522        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 523        int buffer_size;
 524        int ret = 0;
 525        struct sk_buff *skb = NULL;
 526        int noblock;
 527        long timeo;
 528        caif_assert(cf_sk);
 529        ret = sock_error(sk);
 530        if (ret)
 531                goto err;
 532
 533        ret = -EOPNOTSUPP;
 534        if (msg->msg_flags&MSG_OOB)
 535                goto err;
 536
 537        ret = -EOPNOTSUPP;
 538        if (msg->msg_namelen)
 539                goto err;
 540
 541        ret = -EINVAL;
 542        if (unlikely(msg->msg_iov->iov_base == NULL))
 543                goto err;
 544        noblock = msg->msg_flags & MSG_DONTWAIT;
 545
 546        timeo = sock_sndtimeo(sk, noblock);
 547        timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 548                                1, timeo, &ret);
 549
 550        if (ret)
 551                goto err;
 552        ret = -EPIPE;
 553        if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 554                sock_flag(sk, SOCK_DEAD) ||
 555                (sk->sk_shutdown & RCV_SHUTDOWN))
 556                goto err;
 557
 558        /* Error if trying to write more than maximum frame size. */
 559        ret = -EMSGSIZE;
 560        if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 561                goto err;
 562
 563        buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 564
 565        ret = -ENOMEM;
 566        skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 567
 568        if (!skb || skb_tailroom(skb) < buffer_size)
 569                goto err;
 570
 571        skb_reserve(skb, cf_sk->headroom);
 572
 573        ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 574
 575        if (ret)
 576                goto err;
 577        ret = transmit_skb(skb, cf_sk, noblock, timeo);
 578        if (ret < 0)
 579                /* skb is already freed */
 580                return ret;
 581
 582        return len;
 583err:
 584        kfree_skb(skb);
 585        return ret;
 586}
 587
 588/*
 589 * Copied from unix_stream_sendmsg and adapted to CAIF:
 590 * Changed removed permission handling and added waiting for flow on
 591 * and other minor adaptations.
 592 */
 593static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 594                                struct msghdr *msg, size_t len)
 595{
 596        struct sock *sk = sock->sk;
 597        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 598        int err, size;
 599        struct sk_buff *skb;
 600        int sent = 0;
 601        long timeo;
 602
 603        err = -EOPNOTSUPP;
 604        if (unlikely(msg->msg_flags&MSG_OOB))
 605                goto out_err;
 606
 607        if (unlikely(msg->msg_namelen))
 608                goto out_err;
 609
 610        timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 611        timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 612
 613        if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 614                goto pipe_err;
 615
 616        while (sent < len) {
 617
 618                size = len-sent;
 619
 620                if (size > cf_sk->maxframe)
 621                        size = cf_sk->maxframe;
 622
 623                /* If size is more than half of sndbuf, chop up message */
 624                if (size > ((sk->sk_sndbuf >> 1) - 64))
 625                        size = (sk->sk_sndbuf >> 1) - 64;
 626
 627                if (size > SKB_MAX_ALLOC)
 628                        size = SKB_MAX_ALLOC;
 629
 630                skb = sock_alloc_send_skb(sk,
 631                                        size + cf_sk->headroom +
 632                                        cf_sk->tailroom,
 633                                        msg->msg_flags&MSG_DONTWAIT,
 634                                        &err);
 635                if (skb == NULL)
 636                        goto out_err;
 637
 638                skb_reserve(skb, cf_sk->headroom);
 639                /*
 640                 *      If you pass two values to the sock_alloc_send_skb
 641                 *      it tries to grab the large buffer with GFP_NOFS
 642                 *      (which can fail easily), and if it fails grab the
 643                 *      fallback size buffer which is under a page and will
 644                 *      succeed. [Alan]
 645                 */
 646                size = min_t(int, size, skb_tailroom(skb));
 647
 648                err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 649                if (err) {
 650                        kfree_skb(skb);
 651                        goto out_err;
 652                }
 653                err = transmit_skb(skb, cf_sk,
 654                                msg->msg_flags&MSG_DONTWAIT, timeo);
 655                if (err < 0)
 656                        /* skb is already freed */
 657                        goto pipe_err;
 658
 659                sent += size;
 660        }
 661
 662        return sent;
 663
 664pipe_err:
 665        if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 666                send_sig(SIGPIPE, current, 0);
 667        err = -EPIPE;
 668out_err:
 669        return sent ? : err;
 670}
 671
 672static int setsockopt(struct socket *sock,
 673                        int lvl, int opt, char __user *ov, unsigned int ol)
 674{
 675        struct sock *sk = sock->sk;
 676        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 677        int linksel;
 678
 679        if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 680                return -ENOPROTOOPT;
 681
 682        switch (opt) {
 683        case CAIFSO_LINK_SELECT:
 684                if (ol < sizeof(int))
 685                        return -EINVAL;
 686                if (lvl != SOL_CAIF)
 687                        goto bad_sol;
 688                if (copy_from_user(&linksel, ov, sizeof(int)))
 689                        return -EINVAL;
 690                lock_sock(&(cf_sk->sk));
 691                cf_sk->conn_req.link_selector = linksel;
 692                release_sock(&cf_sk->sk);
 693                return 0;
 694
 695        case CAIFSO_REQ_PARAM:
 696                if (lvl != SOL_CAIF)
 697                        goto bad_sol;
 698                if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 699                        return -ENOPROTOOPT;
 700                lock_sock(&(cf_sk->sk));
 701                if (ol > sizeof(cf_sk->conn_req.param.data) ||
 702                        copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 703                        release_sock(&cf_sk->sk);
 704                        return -EINVAL;
 705                }
 706                cf_sk->conn_req.param.size = ol;
 707                release_sock(&cf_sk->sk);
 708                return 0;
 709
 710        default:
 711                return -ENOPROTOOPT;
 712        }
 713
 714        return 0;
 715bad_sol:
 716        return -ENOPROTOOPT;
 717
 718}
 719
 720/*
 721 * caif_connect() - Connect a CAIF Socket
 722 * Copied and modified af_irda.c:irda_connect().
 723 *
 724 * Note : by consulting "errno", the user space caller may learn the cause
 725 * of the failure. Most of them are visible in the function, others may come
 726 * from subroutines called and are listed here :
 727 *  o -EAFNOSUPPORT: bad socket family or type.
 728 *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 729 *  o -EINVAL: bad socket address, or CAIF link type
 730 *  o -ECONNREFUSED: remote end refused the connection.
 731 *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 732 *  o -EISCONN: already connected.
 733 *  o -ETIMEDOUT: Connection timed out (send timeout)
 734 *  o -ENODEV: No link layer to send request
 735 *  o -ECONNRESET: Received Shutdown indication or lost link layer
 736 *  o -ENOMEM: Out of memory
 737 *
 738 *  State Strategy:
 739 *  o sk_state: holds the CAIF_* protocol state, it's updated by
 740 *      caif_ctrl_cb.
 741 *  o sock->state: holds the SS_* socket state and is updated by connect and
 742 *      disconnect.
 743 */
 744static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 745                        int addr_len, int flags)
 746{
 747        struct sock *sk = sock->sk;
 748        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 749        long timeo;
 750        int err;
 751        int ifindex, headroom, tailroom;
 752        unsigned int mtu;
 753        struct net_device *dev;
 754
 755        lock_sock(sk);
 756
 757        err = -EAFNOSUPPORT;
 758        if (uaddr->sa_family != AF_CAIF)
 759                goto out;
 760
 761        switch (sock->state) {
 762        case SS_UNCONNECTED:
 763                /* Normal case, a fresh connect */
 764                caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 765                break;
 766        case SS_CONNECTING:
 767                switch (sk->sk_state) {
 768                case CAIF_CONNECTED:
 769                        sock->state = SS_CONNECTED;
 770                        err = -EISCONN;
 771                        goto out;
 772                case CAIF_DISCONNECTED:
 773                        /* Reconnect allowed */
 774                        break;
 775                case CAIF_CONNECTING:
 776                        err = -EALREADY;
 777                        if (flags & O_NONBLOCK)
 778                                goto out;
 779                        goto wait_connect;
 780                }
 781                break;
 782        case SS_CONNECTED:
 783                caif_assert(sk->sk_state == CAIF_CONNECTED ||
 784                                sk->sk_state == CAIF_DISCONNECTED);
 785                if (sk->sk_shutdown & SHUTDOWN_MASK) {
 786                        /* Allow re-connect after SHUTDOWN_IND */
 787                        caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 788                        caif_free_client(&cf_sk->layer);
 789                        break;
 790                }
 791                /* No reconnect on a seqpacket socket */
 792                err = -EISCONN;
 793                goto out;
 794        case SS_DISCONNECTING:
 795        case SS_FREE:
 796                caif_assert(1); /*Should never happen */
 797                break;
 798        }
 799        sk->sk_state = CAIF_DISCONNECTED;
 800        sock->state = SS_UNCONNECTED;
 801        sk_stream_kill_queues(&cf_sk->sk);
 802
 803        err = -EINVAL;
 804        if (addr_len != sizeof(struct sockaddr_caif))
 805                goto out;
 806
 807        memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 808                sizeof(struct sockaddr_caif));
 809
 810        /* Move to connecting socket, start sending Connect Requests */
 811        sock->state = SS_CONNECTING;
 812        sk->sk_state = CAIF_CONNECTING;
 813
 814        /* Check priority value comming from socket */
 815        /* if priority value is out of range it will be ajusted */
 816        if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 817                cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 818        else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 819                cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 820        else
 821                cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 822
 823        /*ifindex = id of the interface.*/
 824        cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 825
 826        cf_sk->layer.receive = caif_sktrecv_cb;
 827
 828        err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 829                                &cf_sk->layer, &ifindex, &headroom, &tailroom);
 830
 831        if (err < 0) {
 832                cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 833                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 834                goto out;
 835        }
 836
 837        err = -ENODEV;
 838        rcu_read_lock();
 839        dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 840        if (!dev) {
 841                rcu_read_unlock();
 842                goto out;
 843        }
 844        cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 845        mtu = dev->mtu;
 846        rcu_read_unlock();
 847
 848        cf_sk->tailroom = tailroom;
 849        cf_sk->maxframe = mtu - (headroom + tailroom);
 850        if (cf_sk->maxframe < 1) {
 851                pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 852                err = -ENODEV;
 853                goto out;
 854        }
 855
 856        err = -EINPROGRESS;
 857wait_connect:
 858
 859        if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 860                goto out;
 861
 862        timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 863
 864        release_sock(sk);
 865        err = -ERESTARTSYS;
 866        timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 867                        sk->sk_state != CAIF_CONNECTING,
 868                        timeo);
 869        lock_sock(sk);
 870        if (timeo < 0)
 871                goto out; /* -ERESTARTSYS */
 872
 873        err = -ETIMEDOUT;
 874        if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 875                goto out;
 876        if (sk->sk_state != CAIF_CONNECTED) {
 877                sock->state = SS_UNCONNECTED;
 878                err = sock_error(sk);
 879                if (!err)
 880                        err = -ECONNREFUSED;
 881                goto out;
 882        }
 883        sock->state = SS_CONNECTED;
 884        err = 0;
 885out:
 886        release_sock(sk);
 887        return err;
 888}
 889
 890/*
 891 * caif_release() - Disconnect a CAIF Socket
 892 * Copied and modified af_irda.c:irda_release().
 893 */
 894static int caif_release(struct socket *sock)
 895{
 896        struct sock *sk = sock->sk;
 897        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 898
 899        if (!sk)
 900                return 0;
 901
 902        set_tx_flow_off(cf_sk);
 903
 904        /*
 905         * Ensure that packets are not queued after this point in time.
 906         * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 907         * this ensures no packets when sock is dead.
 908         */
 909        spin_lock_bh(&sk->sk_receive_queue.lock);
 910        sock_set_flag(sk, SOCK_DEAD);
 911        spin_unlock_bh(&sk->sk_receive_queue.lock);
 912        sock->sk = NULL;
 913
 914        WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 915        if (cf_sk->debugfs_socket_dir != NULL)
 916                debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 917
 918        lock_sock(&(cf_sk->sk));
 919        sk->sk_state = CAIF_DISCONNECTED;
 920        sk->sk_shutdown = SHUTDOWN_MASK;
 921
 922        caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 923        cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 924        wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 925
 926        sock_orphan(sk);
 927        sk_stream_kill_queues(&cf_sk->sk);
 928        release_sock(sk);
 929        sock_put(sk);
 930        return 0;
 931}
 932
 933/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 934static unsigned int caif_poll(struct file *file,
 935                                struct socket *sock, poll_table *wait)
 936{
 937        struct sock *sk = sock->sk;
 938        unsigned int mask;
 939        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 940
 941        sock_poll_wait(file, sk_sleep(sk), wait);
 942        mask = 0;
 943
 944        /* exceptional events? */
 945        if (sk->sk_err)
 946                mask |= POLLERR;
 947        if (sk->sk_shutdown == SHUTDOWN_MASK)
 948                mask |= POLLHUP;
 949        if (sk->sk_shutdown & RCV_SHUTDOWN)
 950                mask |= POLLRDHUP;
 951
 952        /* readable? */
 953        if (!skb_queue_empty(&sk->sk_receive_queue) ||
 954                (sk->sk_shutdown & RCV_SHUTDOWN))
 955                mask |= POLLIN | POLLRDNORM;
 956
 957        /*
 958         * we set writable also when the other side has shut down the
 959         * connection. This prevents stuck sockets.
 960         */
 961        if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 962                mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 963
 964        return mask;
 965}
 966
 967static const struct proto_ops caif_seqpacket_ops = {
 968        .family = PF_CAIF,
 969        .owner = THIS_MODULE,
 970        .release = caif_release,
 971        .bind = sock_no_bind,
 972        .connect = caif_connect,
 973        .socketpair = sock_no_socketpair,
 974        .accept = sock_no_accept,
 975        .getname = sock_no_getname,
 976        .poll = caif_poll,
 977        .ioctl = sock_no_ioctl,
 978        .listen = sock_no_listen,
 979        .shutdown = sock_no_shutdown,
 980        .setsockopt = setsockopt,
 981        .getsockopt = sock_no_getsockopt,
 982        .sendmsg = caif_seqpkt_sendmsg,
 983        .recvmsg = caif_seqpkt_recvmsg,
 984        .mmap = sock_no_mmap,
 985        .sendpage = sock_no_sendpage,
 986};
 987
 988static const struct proto_ops caif_stream_ops = {
 989        .family = PF_CAIF,
 990        .owner = THIS_MODULE,
 991        .release = caif_release,
 992        .bind = sock_no_bind,
 993        .connect = caif_connect,
 994        .socketpair = sock_no_socketpair,
 995        .accept = sock_no_accept,
 996        .getname = sock_no_getname,
 997        .poll = caif_poll,
 998        .ioctl = sock_no_ioctl,
 999        .listen = sock_no_listen,
1000        .shutdown = sock_no_shutdown,
1001        .setsockopt = setsockopt,
1002        .getsockopt = sock_no_getsockopt,
1003        .sendmsg = caif_stream_sendmsg,
1004        .recvmsg = caif_stream_recvmsg,
1005        .mmap = sock_no_mmap,
1006        .sendpage = sock_no_sendpage,
1007};
1008
1009/* This function is called when a socket is finally destroyed. */
1010static void caif_sock_destructor(struct sock *sk)
1011{
1012        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1013        caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1014        caif_assert(sk_unhashed(sk));
1015        caif_assert(!sk->sk_socket);
1016        if (!sock_flag(sk, SOCK_DEAD)) {
1017                pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1018                return;
1019        }
1020        sk_stream_kill_queues(&cf_sk->sk);
1021        caif_free_client(&cf_sk->layer);
1022}
1023
1024static int caif_create(struct net *net, struct socket *sock, int protocol,
1025                        int kern)
1026{
1027        struct sock *sk = NULL;
1028        struct caifsock *cf_sk = NULL;
1029        static struct proto prot = {.name = "PF_CAIF",
1030                .owner = THIS_MODULE,
1031                .obj_size = sizeof(struct caifsock),
1032        };
1033
1034        if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1035                return -EPERM;
1036        /*
1037         * The sock->type specifies the socket type to use.
1038         * The CAIF socket is a packet stream in the sense
1039         * that it is packet based. CAIF trusts the reliability
1040         * of the link, no resending is implemented.
1041         */
1042        if (sock->type == SOCK_SEQPACKET)
1043                sock->ops = &caif_seqpacket_ops;
1044        else if (sock->type == SOCK_STREAM)
1045                sock->ops = &caif_stream_ops;
1046        else
1047                return -ESOCKTNOSUPPORT;
1048
1049        if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1050                return -EPROTONOSUPPORT;
1051        /*
1052         * Set the socket state to unconnected.  The socket state
1053         * is really not used at all in the net/core or socket.c but the
1054         * initialization makes sure that sock->state is not uninitialized.
1055         */
1056        sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1057        if (!sk)
1058                return -ENOMEM;
1059
1060        cf_sk = container_of(sk, struct caifsock, sk);
1061
1062        /* Store the protocol */
1063        sk->sk_protocol = (unsigned char) protocol;
1064
1065        /* Initialize default priority for well-known cases */
1066        switch (protocol) {
1067        case CAIFPROTO_AT:
1068                sk->sk_priority = TC_PRIO_CONTROL;
1069                break;
1070        case CAIFPROTO_RFM:
1071                sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1072                break;
1073        default:
1074                sk->sk_priority = TC_PRIO_BESTEFFORT;
1075        }
1076
1077        /*
1078         * Lock in order to try to stop someone from opening the socket
1079         * too early.
1080         */
1081        lock_sock(&(cf_sk->sk));
1082
1083        /* Initialize the nozero default sock structure data. */
1084        sock_init_data(sock, sk);
1085        sk->sk_destruct = caif_sock_destructor;
1086
1087        mutex_init(&cf_sk->readlock); /* single task reading lock */
1088        cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1089        cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1090        cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1091
1092        set_tx_flow_off(cf_sk);
1093        set_rx_flow_on(cf_sk);
1094
1095        /* Set default options on configuration */
1096        cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1097        cf_sk->conn_req.protocol = protocol;
1098        release_sock(&cf_sk->sk);
1099        return 0;
1100}
1101
1102
1103static struct net_proto_family caif_family_ops = {
1104        .family = PF_CAIF,
1105        .create = caif_create,
1106        .owner = THIS_MODULE,
1107};
1108
1109static int __init caif_sktinit_module(void)
1110{
1111        int err = sock_register(&caif_family_ops);
1112        if (!err)
1113                return err;
1114        return 0;
1115}
1116
1117static void __exit caif_sktexit_module(void)
1118{
1119        sock_unregister(PF_CAIF);
1120}
1121module_init(caif_sktinit_module);
1122module_exit(caif_sktexit_module);
1123
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