net/caif/caif_socket.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland
   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
  29 MODULE_LICENSE("GPL");
  30 MODULE_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  */
  37 enum 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
  46 struct 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
  56 static 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
  62 static 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
  68 static 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
  74 static 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
  80 static 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
  86 static 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
  92 static 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
  99 static 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
 106 static 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
 112 static 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  */
 124 static 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 */
 170 static 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
 186 static 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
 192 static 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 */
 199 static 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
 259 static 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  */
 276 static 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;
 303 out_free:
 304         skb_free_datagram(sk, skb);
 305         caif_check_flow_release(sk);
 306         return ret;
 307
 308 read_error:
 309         return ret;
 310 }
 311
 312
 313 /* Copied from unix_stream_wait_data, identical except for lock call. */
 314 static 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  */
 348 static 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         /*
 363          * Lock the socket to prevent queue disordering
 364          * while sleeps in memcpy_tomsg
 365          */
 366         err = -EAGAIN;
 367         if (sk->sk_state == CAIF_CONNECTING)
 368                 goto out;
 369
 370         caif_read_lock(sk);
 371         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 372         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 373
 374         do {
 375                 int chunk;
 376                 struct sk_buff *skb;
 377
 378                 lock_sock(sk);
 379                 skb = skb_dequeue(&sk->sk_receive_queue);
 380                 caif_check_flow_release(sk);
 381
 382                 if (skb == NULL) {
 383                         if (copied >= target)
 384                                 goto unlock;
 385                         /*
 386                          *      POSIX 1003.1g mandates this order.
 387                          */
 388                         err = sock_error(sk);
 389                         if (err)
 390                                 goto unlock;
 391                         err = -ECONNRESET;
 392                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 393                                 goto unlock;
 394
 395                         err = -EPIPE;
 396                         if (sk->sk_state != CAIF_CONNECTED)
 397                                 goto unlock;
 398                         if (sock_flag(sk, SOCK_DEAD))
 399                                 goto unlock;
 400
 401                         release_sock(sk);
 402
 403                         err = -EAGAIN;
 404                         if (!timeo)
 405                                 break;
 406
 407                         caif_read_unlock(sk);
 408
 409                         timeo = caif_stream_data_wait(sk, timeo);
 410
 411                         if (signal_pending(current)) {
 412                                 err = sock_intr_errno(timeo);
 413                                 goto out;
 414                         }
 415                         caif_read_lock(sk);
 416                         continue;
 417 unlock:
 418                         release_sock(sk);
 419                         break;
 420                 }
 421                 release_sock(sk);
 422                 chunk = min_t(unsigned int, skb->len, size);
 423                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
 424                         skb_queue_head(&sk->sk_receive_queue, skb);
 425                         if (copied == 0)
 426                                 copied = -EFAULT;
 427                         break;
 428                 }
 429                 copied += chunk;
 430                 size -= chunk;
 431
 432                 /* Mark read part of skb as used */
 433                 if (!(flags & MSG_PEEK)) {
 434                         skb_pull(skb, chunk);
 435
 436                         /* put the skb back if we didn't use it up. */
 437                         if (skb->len) {
 438                                 skb_queue_head(&sk->sk_receive_queue, skb);
 439                                 break;
 440                         }
 441                         kfree_skb(skb);
 442
 443                 } else {
 444                         /*
 445                          * It is questionable, see note in unix_dgram_recvmsg.
 446                          */
 447                         /* put message back and return */
 448                         skb_queue_head(&sk->sk_receive_queue, skb);
 449                         break;
 450                 }
 451         } while (size);
 452         caif_read_unlock(sk);
 453
 454 out:
 455         return copied ? : err;
 456 }
 457
 458 /*
 459  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 460  * CAIF flow-on and sock_writable.
 461  */
 462 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 463                                   int wait_writeable, long timeo, int *err)
 464 {
 465         struct sock *sk = &cf_sk->sk;
 466         DEFINE_WAIT(wait);
 467         for (;;) {
 468                 *err = 0;
 469                 if (tx_flow_is_on(cf_sk) &&
 470                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 471                         break;
 472                 *err = -ETIMEDOUT;
 473                 if (!timeo)
 474                         break;
 475                 *err = -ERESTARTSYS;
 476                 if (signal_pending(current))
 477                         break;
 478                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 479                 *err = -ECONNRESET;
 480                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 481                         break;
 482                 *err = -sk->sk_err;
 483                 if (sk->sk_err)
 484                         break;
 485                 *err = -EPIPE;
 486                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 487                         break;
 488                 timeo = schedule_timeout(timeo);
 489         }
 490         finish_wait(sk_sleep(sk), &wait);
 491         return timeo;
 492 }
 493
 494 /*
 495  * Transmit a SKB. The device may temporarily request re-transmission
 496  * by returning EAGAIN.
 497  */
 498 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 499                         int noblock, long timeo)
 500 {
 501         struct cfpkt *pkt;
 502
 503         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 504         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 505         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 506
 507         if (cf_sk->layer.dn == NULL) {
 508                 kfree_skb(skb);
 509                 return -EINVAL;
 510         }
 511
 512         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 513 }
 514
 515 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 516 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 517                                struct msghdr *msg, size_t len)
 518 {
 519         struct sock *sk = sock->sk;
 520         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 521         int buffer_size;
 522         int ret = 0;
 523         struct sk_buff *skb = NULL;
 524         int noblock;
 525         long timeo;
 526         caif_assert(cf_sk);
 527         ret = sock_error(sk);
 528         if (ret)
 529                 goto err;
 530
 531         ret = -EOPNOTSUPP;
 532         if (msg->msg_flags&MSG_OOB)
 533                 goto err;
 534
 535         ret = -EOPNOTSUPP;
 536         if (msg->msg_namelen)
 537                 goto err;
 538
 539         ret = -EINVAL;
 540         if (unlikely(msg->msg_iov->iov_base == NULL))
 541                 goto err;
 542         noblock = msg->msg_flags & MSG_DONTWAIT;
 543
 544         timeo = sock_sndtimeo(sk, noblock);
 545         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 546                                 1, timeo, &ret);
 547
 548         if (ret)
 549                 goto err;
 550         ret = -EPIPE;
 551         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 552                 sock_flag(sk, SOCK_DEAD) ||
 553                 (sk->sk_shutdown & RCV_SHUTDOWN))
 554                 goto err;
 555
 556         /* Error if trying to write more than maximum frame size. */
 557         ret = -EMSGSIZE;
 558         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 559                 goto err;
 560
 561         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 562
 563         ret = -ENOMEM;
 564         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 565
 566         if (!skb || skb_tailroom(skb) < buffer_size)
 567                 goto err;
 568
 569         skb_reserve(skb, cf_sk->headroom);
 570
 571         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 572
 573         if (ret)
 574                 goto err;
 575         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 576         if (ret < 0)
 577                 /* skb is already freed */
 578                 return ret;
 579
 580         return len;
 581 err:
 582         kfree_skb(skb);
 583         return ret;
 584 }
 585
 586 /*
 587  * Copied from unix_stream_sendmsg and adapted to CAIF:
 588  * Changed removed permission handling and added waiting for flow on
 589  * and other minor adaptations.
 590  */
 591 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 592                                struct msghdr *msg, size_t len)
 593 {
 594         struct sock *sk = sock->sk;
 595         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 596         int err, size;
 597         struct sk_buff *skb;
 598         int sent = 0;
 599         long timeo;
 600
 601         err = -EOPNOTSUPP;
 602         if (unlikely(msg->msg_flags&MSG_OOB))
 603                 goto out_err;
 604
 605         if (unlikely(msg->msg_namelen))
 606                 goto out_err;
 607
 608         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 609         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 610
 611         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 612                 goto pipe_err;
 613
 614         while (sent < len) {
 615
 616                 size = len-sent;
 617
 618                 if (size > cf_sk->maxframe)
 619                         size = cf_sk->maxframe;
 620
 621                 /* If size is more than half of sndbuf, chop up message */
 622                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 623                         size = (sk->sk_sndbuf >> 1) - 64;
 624
 625                 if (size > SKB_MAX_ALLOC)
 626                         size = SKB_MAX_ALLOC;
 627
 628                 skb = sock_alloc_send_skb(sk,
 629                                         size + cf_sk->headroom +
 630                                         cf_sk->tailroom,
 631                                         msg->msg_flags&MSG_DONTWAIT,
 632                                         &err);
 633                 if (skb == NULL)
 634                         goto out_err;
 635
 636                 skb_reserve(skb, cf_sk->headroom);
 637                 /*
 638                  *      If you pass two values to the sock_alloc_send_skb
 639                  *      it tries to grab the large buffer with GFP_NOFS
 640                  *      (which can fail easily), and if it fails grab the
 641                  *      fallback size buffer which is under a page and will
 642                  *      succeed. [Alan]
 643                  */
 644                 size = min_t(int, size, skb_tailroom(skb));
 645
 646                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 647                 if (err) {
 648                         kfree_skb(skb);
 649                         goto out_err;
 650                 }
 651                 err = transmit_skb(skb, cf_sk,
 652                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 653                 if (err < 0)
 654                         /* skb is already freed */
 655                         goto pipe_err;
 656
 657                 sent += size;
 658         }
 659
 660         return sent;
 661
 662 pipe_err:
 663         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 664                 send_sig(SIGPIPE, current, 0);
 665         err = -EPIPE;
 666 out_err:
 667         return sent ? : err;
 668 }
 669
 670 static int setsockopt(struct socket *sock,
 671                       int lvl, int opt, char __user *ov, unsigned int ol)
 672 {
 673         struct sock *sk = sock->sk;
 674         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 675         int linksel;
 676
 677         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 678                 return -ENOPROTOOPT;
 679
 680         switch (opt) {
 681         case CAIFSO_LINK_SELECT:
 682                 if (ol < sizeof(int))
 683                         return -EINVAL;
 684                 if (lvl != SOL_CAIF)
 685                         goto bad_sol;
 686                 if (copy_from_user(&linksel, ov, sizeof(int)))
 687                         return -EINVAL;
 688                 lock_sock(&(cf_sk->sk));
 689                 cf_sk->conn_req.link_selector = linksel;
 690                 release_sock(&cf_sk->sk);
 691                 return 0;
 692
 693         case CAIFSO_REQ_PARAM:
 694                 if (lvl != SOL_CAIF)
 695                         goto bad_sol;
 696                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 697                         return -ENOPROTOOPT;
 698                 lock_sock(&(cf_sk->sk));
 699                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 700                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 701                         release_sock(&cf_sk->sk);
 702                         return -EINVAL;
 703                 }
 704                 cf_sk->conn_req.param.size = ol;
 705                 release_sock(&cf_sk->sk);
 706                 return 0;
 707
 708         default:
 709                 return -ENOPROTOOPT;
 710         }
 711
 712         return 0;
 713 bad_sol:
 714         return -ENOPROTOOPT;
 715
 716 }
 717
 718 /*
 719  * caif_connect() - Connect a CAIF Socket
 720  * Copied and modified af_irda.c:irda_connect().
 721  *
 722  * Note : by consulting "errno", the user space caller may learn the cause
 723  * of the failure. Most of them are visible in the function, others may come
 724  * from subroutines called and are listed here :
 725  *  o -EAFNOSUPPORT: bad socket family or type.
 726  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 727  *  o -EINVAL: bad socket address, or CAIF link type
 728  *  o -ECONNREFUSED: remote end refused the connection.
 729  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 730  *  o -EISCONN: already connected.
 731  *  o -ETIMEDOUT: Connection timed out (send timeout)
 732  *  o -ENODEV: No link layer to send request
 733  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 734  *  o -ENOMEM: Out of memory
 735  *
 736  *  State Strategy:
 737  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 738  *      caif_ctrl_cb.
 739  *  o sock->state: holds the SS_* socket state and is updated by connect and
 740  *      disconnect.
 741  */
 742 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 743                         int addr_len, int flags)
 744 {
 745         struct sock *sk = sock->sk;
 746         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 747         long timeo;
 748         int err;
 749         int ifindex, headroom, tailroom;
 750         unsigned int mtu;
 751         struct net_device *dev;
 752
 753         lock_sock(sk);
 754
 755         err = -EAFNOSUPPORT;
 756         if (uaddr->sa_family != AF_CAIF)
 757                 goto out;
 758
 759         switch (sock->state) {
 760         case SS_UNCONNECTED:
 761                 /* Normal case, a fresh connect */
 762                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 763                 break;
 764         case SS_CONNECTING:
 765                 switch (sk->sk_state) {
 766                 case CAIF_CONNECTED:
 767                         sock->state = SS_CONNECTED;
 768                         err = -EISCONN;
 769                         goto out;
 770                 case CAIF_DISCONNECTED:
 771                         /* Reconnect allowed */
 772                         break;
 773                 case CAIF_CONNECTING:
 774                         err = -EALREADY;
 775                         if (flags & O_NONBLOCK)
 776                                 goto out;
 777                         goto wait_connect;
 778                 }
 779                 break;
 780         case SS_CONNECTED:
 781                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 782                                 sk->sk_state == CAIF_DISCONNECTED);
 783                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 784                         /* Allow re-connect after SHUTDOWN_IND */
 785                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 786                         caif_free_client(&cf_sk->layer);
 787                         break;
 788                 }
 789                 /* No reconnect on a seqpacket socket */
 790                 err = -EISCONN;
 791                 goto out;
 792         case SS_DISCONNECTING:
 793         case SS_FREE:
 794                 caif_assert(1); /*Should never happen */
 795                 break;
 796         }
 797         sk->sk_state = CAIF_DISCONNECTED;
 798         sock->state = SS_UNCONNECTED;
 799         sk_stream_kill_queues(&cf_sk->sk);
 800
 801         err = -EINVAL;
 802         if (addr_len != sizeof(struct sockaddr_caif))
 803                 goto out;
 804
 805         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 806                 sizeof(struct sockaddr_caif));
 807
 808         /* Move to connecting socket, start sending Connect Requests */
 809         sock->state = SS_CONNECTING;
 810         sk->sk_state = CAIF_CONNECTING;
 811
 812         /* Check priority value comming from socket */
 813         /* if priority value is out of range it will be ajusted */
 814         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 815                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 816         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 817                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 818         else
 819                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 820
 821         /*ifindex = id of the interface.*/
 822         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 823
 824         cf_sk->layer.receive = caif_sktrecv_cb;
 825
 826         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 827                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 828
 829         if (err < 0) {
 830                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 831                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 832                 goto out;
 833         }
 834
 835         err = -ENODEV;
 836         rcu_read_lock();
 837         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 838         if (!dev) {
 839                 rcu_read_unlock();
 840                 goto out;
 841         }
 842         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 843         mtu = dev->mtu;
 844         rcu_read_unlock();
 845
 846         cf_sk->tailroom = tailroom;
 847         cf_sk->maxframe = mtu - (headroom + tailroom);
 848         if (cf_sk->maxframe < 1) {
 849                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 850                 err = -ENODEV;
 851                 goto out;
 852         }
 853
 854         err = -EINPROGRESS;
 855 wait_connect:
 856
 857         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 858                 goto out;
 859
 860         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 861
 862         release_sock(sk);
 863         err = -ERESTARTSYS;
 864         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 865                         sk->sk_state != CAIF_CONNECTING,
 866                         timeo);
 867         lock_sock(sk);
 868         if (timeo < 0)
 869                 goto out; /* -ERESTARTSYS */
 870
 871         err = -ETIMEDOUT;
 872         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 873                 goto out;
 874         if (sk->sk_state != CAIF_CONNECTED) {
 875                 sock->state = SS_UNCONNECTED;
 876                 err = sock_error(sk);
 877                 if (!err)
 878                         err = -ECONNREFUSED;
 879                 goto out;
 880         }
 881         sock->state = SS_CONNECTED;
 882         err = 0;
 883 out:
 884         release_sock(sk);
 885         return err;
 886 }
 887
 888 /*
 889  * caif_release() - Disconnect a CAIF Socket
 890  * Copied and modified af_irda.c:irda_release().
 891  */
 892 static int caif_release(struct socket *sock)
 893 {
 894         struct sock *sk = sock->sk;
 895         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 896
 897         if (!sk)
 898                 return 0;
 899
 900         set_tx_flow_off(cf_sk);
 901
 902         /*
 903          * Ensure that packets are not queued after this point in time.
 904          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 905          * this ensures no packets when sock is dead.
 906          */
 907         spin_lock_bh(&sk->sk_receive_queue.lock);
 908         sock_set_flag(sk, SOCK_DEAD);
 909         spin_unlock_bh(&sk->sk_receive_queue.lock);
 910         sock->sk = NULL;
 911
 912         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 913         if (cf_sk->debugfs_socket_dir != NULL)
 914                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 915
 916         lock_sock(&(cf_sk->sk));
 917         sk->sk_state = CAIF_DISCONNECTED;
 918         sk->sk_shutdown = SHUTDOWN_MASK;
 919
 920         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 921         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 922         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 923
 924         sock_orphan(sk);
 925         sk_stream_kill_queues(&cf_sk->sk);
 926         release_sock(sk);
 927         sock_put(sk);
 928         return 0;
 929 }
 930
 931 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 932 static unsigned int caif_poll(struct file *file,
 933                               struct socket *sock, poll_table *wait)
 934 {
 935         struct sock *sk = sock->sk;
 936         unsigned int mask;
 937         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 938
 939         sock_poll_wait(file, sk_sleep(sk), wait);
 940         mask = 0;
 941
 942         /* exceptional events? */
 943         if (sk->sk_err)
 944                 mask |= POLLERR;
 945         if (sk->sk_shutdown == SHUTDOWN_MASK)
 946                 mask |= POLLHUP;
 947         if (sk->sk_shutdown & RCV_SHUTDOWN)
 948                 mask |= POLLRDHUP;
 949
 950         /* readable? */
 951         if (!skb_queue_empty(&sk->sk_receive_queue) ||
 952                 (sk->sk_shutdown & RCV_SHUTDOWN))
 953                 mask |= POLLIN | POLLRDNORM;
 954
 955         /*
 956          * we set writable also when the other side has shut down the
 957          * connection. This prevents stuck sockets.
 958          */
 959         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 960                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 961
 962         return mask;
 963 }
 964
 965 static const struct proto_ops caif_seqpacket_ops = {
 966         .family = PF_CAIF,
 967         .owner = THIS_MODULE,
 968         .release = caif_release,
 969         .bind = sock_no_bind,
 970         .connect = caif_connect,
 971         .socketpair = sock_no_socketpair,
 972         .accept = sock_no_accept,
 973         .getname = sock_no_getname,
 974         .poll = caif_poll,
 975         .ioctl = sock_no_ioctl,
 976         .listen = sock_no_listen,
 977         .shutdown = sock_no_shutdown,
 978         .setsockopt = setsockopt,
 979         .getsockopt = sock_no_getsockopt,
 980         .sendmsg = caif_seqpkt_sendmsg,
 981         .recvmsg = caif_seqpkt_recvmsg,
 982         .mmap = sock_no_mmap,
 983         .sendpage = sock_no_sendpage,
 984 };
 985
 986 static const struct proto_ops caif_stream_ops = {
 987         .family = PF_CAIF,
 988         .owner = THIS_MODULE,
 989         .release = caif_release,
 990         .bind = sock_no_bind,
 991         .connect = caif_connect,
 992         .socketpair = sock_no_socketpair,
 993         .accept = sock_no_accept,
 994         .getname = sock_no_getname,
 995         .poll = caif_poll,
 996         .ioctl = sock_no_ioctl,
 997         .listen = sock_no_listen,
 998         .shutdown = sock_no_shutdown,
 999         .setsockopt = setsockopt,
1000         .getsockopt = sock_no_getsockopt,
1001         .sendmsg = caif_stream_sendmsg,
1002         .recvmsg = caif_stream_recvmsg,
1003         .mmap = sock_no_mmap,
1004         .sendpage = sock_no_sendpage,
1005 };
1006
1007 /* This function is called when a socket is finally destroyed. */
1008 static void caif_sock_destructor(struct sock *sk)
1009 {
1010         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1011         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1012         caif_assert(sk_unhashed(sk));
1013         caif_assert(!sk->sk_socket);
1014         if (!sock_flag(sk, SOCK_DEAD)) {
1015                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1016                 return;
1017         }
1018         sk_stream_kill_queues(&cf_sk->sk);
1019         caif_free_client(&cf_sk->layer);
1020 }
1021
1022 static int caif_create(struct net *net, struct socket *sock, int protocol,
1023                        int kern)
1024 {
1025         struct sock *sk = NULL;
1026         struct caifsock *cf_sk = NULL;
1027         static struct proto prot = {.name = "PF_CAIF",
1028                 .owner = THIS_MODULE,
1029                 .obj_size = sizeof(struct caifsock),
1030         };
1031
1032         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1033                 return -EPERM;
1034         /*
1035          * The sock->type specifies the socket type to use.
1036          * The CAIF socket is a packet stream in the sense
1037          * that it is packet based. CAIF trusts the reliability
1038          * of the link, no resending is implemented.
1039          */
1040         if (sock->type == SOCK_SEQPACKET)
1041                 sock->ops = &caif_seqpacket_ops;
1042         else if (sock->type == SOCK_STREAM)
1043                 sock->ops = &caif_stream_ops;
1044         else
1045                 return -ESOCKTNOSUPPORT;
1046
1047         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1048                 return -EPROTONOSUPPORT;
1049         /*
1050          * Set the socket state to unconnected.  The socket state
1051          * is really not used at all in the net/core or socket.c but the
1052          * initialization makes sure that sock->state is not uninitialized.
1053          */
1054         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1055         if (!sk)
1056                 return -ENOMEM;
1057
1058         cf_sk = container_of(sk, struct caifsock, sk);
1059
1060         /* Store the protocol */
1061         sk->sk_protocol = (unsigned char) protocol;
1062
1063         /* Initialize default priority for well-known cases */
1064         switch (protocol) {
1065         case CAIFPROTO_AT:
1066                 sk->sk_priority = TC_PRIO_CONTROL;
1067                 break;
1068         case CAIFPROTO_RFM:
1069                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1070                 break;
1071         default:
1072                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1073         }
1074
1075         /*
1076          * Lock in order to try to stop someone from opening the socket
1077          * too early.
1078          */
1079         lock_sock(&(cf_sk->sk));
1080
1081         /* Initialize the nozero default sock structure data. */
1082         sock_init_data(sock, sk);
1083         sk->sk_destruct = caif_sock_destructor;
1084
1085         mutex_init(&cf_sk->readlock); /* single task reading lock */
1086         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1087         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1088         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1089
1090         set_tx_flow_off(cf_sk);
1091         set_rx_flow_on(cf_sk);
1092
1093         /* Set default options on configuration */
1094         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1095         cf_sk->conn_req.protocol = protocol;
1096         release_sock(&cf_sk->sk);
1097         return 0;
1098 }
1099
1100
1101 static struct net_proto_family caif_family_ops = {
1102         .family = PF_CAIF,
1103         .create = caif_create,
1104         .owner = THIS_MODULE,
1105 };
1106
1107 static int __init caif_sktinit_module(void)
1108 {
1109         int err = sock_register(&caif_family_ops);
1110         if (!err)
1111                 return err;
1112         return 0;
1113 }
1114
1115 static void __exit caif_sktexit_module(void)
1116 {
1117         sock_unregister(PF_CAIF);
1118 }
1119 module_init(caif_sktinit_module);
1120 module_exit(caif_sktexit_module);