kernel/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         unsigned long flags;
 128         struct sk_buff_head *list = &sk->sk_receive_queue;
 129         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 130
 131         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 132                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 133                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 134                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
 135                                     sk_rcvbuf_lowwater(cf_sk));
 136                 set_rx_flow_off(cf_sk);
 137                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 138         }
 139
 140         err = sk_filter(sk, skb);
 141         if (err)
 142                 return err;
 143         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 144                 set_rx_flow_off(cf_sk);
 145                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 146                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 147         }
 148         skb->dev = NULL;
 149         skb_set_owner_r(skb, sk);
 150         /* Cache the SKB length before we tack it onto the receive
 151          * queue. Once it is added it no longer belongs to us and
 152          * may be freed by other threads of control pulling packets
 153          * from the queue.
 154          */
 155         spin_lock_irqsave(&list->lock, flags);
 156         if (!sock_flag(sk, SOCK_DEAD))
 157                 __skb_queue_tail(list, skb);
 158         spin_unlock_irqrestore(&list->lock, flags);
 159
 160         if (!sock_flag(sk, SOCK_DEAD))
 161                 sk->sk_data_ready(sk);
 162         else
 163                 kfree_skb(skb);
 164         return 0;
 165 }
 166
 167 /* Packet Receive Callback function called from CAIF Stack */
 168 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 169 {
 170         struct caifsock *cf_sk;
 171         struct sk_buff *skb;
 172
 173         cf_sk = container_of(layr, struct caifsock, layer);
 174         skb = cfpkt_tonative(pkt);
 175
 176         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 177                 kfree_skb(skb);
 178                 return 0;
 179         }
 180         caif_queue_rcv_skb(&cf_sk->sk, skb);
 181         return 0;
 182 }
 183
 184 static void cfsk_hold(struct cflayer *layr)
 185 {
 186         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 187         sock_hold(&cf_sk->sk);
 188 }
 189
 190 static void cfsk_put(struct cflayer *layr)
 191 {
 192         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 193         sock_put(&cf_sk->sk);
 194 }
 195
 196 /* Packet Control Callback function called from CAIF */
 197 static void caif_ctrl_cb(struct cflayer *layr,
 198                          enum caif_ctrlcmd flow,
 199                          int phyid)
 200 {
 201         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 202         switch (flow) {
 203         case CAIF_CTRLCMD_FLOW_ON_IND:
 204                 /* OK from modem to start sending again */
 205                 set_tx_flow_on(cf_sk);
 206                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 207                 break;
 208
 209         case CAIF_CTRLCMD_FLOW_OFF_IND:
 210                 /* Modem asks us to shut up */
 211                 set_tx_flow_off(cf_sk);
 212                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 213                 break;
 214
 215         case CAIF_CTRLCMD_INIT_RSP:
 216                 /* We're now connected */
 217                 caif_client_register_refcnt(&cf_sk->layer,
 218                                                 cfsk_hold, cfsk_put);
 219                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 220                 set_tx_flow_on(cf_sk);
 221                 cf_sk->sk.sk_shutdown = 0;
 222                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 223                 break;
 224
 225         case CAIF_CTRLCMD_DEINIT_RSP:
 226                 /* We're now disconnected */
 227                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 228                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 229                 break;
 230
 231         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 232                 /* Connect request failed */
 233                 cf_sk->sk.sk_err = ECONNREFUSED;
 234                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 235                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 236                 /*
 237                  * Socket "standards" seems to require POLLOUT to
 238                  * be set at connect failure.
 239                  */
 240                 set_tx_flow_on(cf_sk);
 241                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 242                 break;
 243
 244         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 245                 /* Modem has closed this connection, or device is down. */
 246                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 247                 cf_sk->sk.sk_err = ECONNRESET;
 248                 set_rx_flow_on(cf_sk);
 249                 cf_sk->sk.sk_error_report(&cf_sk->sk);
 250                 break;
 251
 252         default:
 253                 pr_debug("Unexpected flow command %d\n", flow);
 254         }
 255 }
 256
 257 static void caif_check_flow_release(struct sock *sk)
 258 {
 259         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 260
 261         if (rx_flow_is_on(cf_sk))
 262                 return;
 263
 264         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 265                         set_rx_flow_on(cf_sk);
 266                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 267         }
 268 }
 269
 270 /*
 271  * Copied from unix_dgram_recvmsg, but removed credit checks,
 272  * changed locking, address handling and added MSG_TRUNC.
 273  */
 274 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
 275                                size_t len, int flags)
 276
 277 {
 278         struct sock *sk = sock->sk;
 279         struct sk_buff *skb;
 280         int ret;
 281         int copylen;
 282
 283         ret = -EOPNOTSUPP;
 284         if (flags & MSG_OOB)
 285                 goto read_error;
 286
 287         skb = skb_recv_datagram(sk, flags, 0 , &ret);
 288         if (!skb)
 289                 goto read_error;
 290         copylen = skb->len;
 291         if (len < copylen) {
 292                 m->msg_flags |= MSG_TRUNC;
 293                 copylen = len;
 294         }
 295
 296         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
 297         if (ret)
 298                 goto out_free;
 299
 300         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 301 out_free:
 302         skb_free_datagram(sk, skb);
 303         caif_check_flow_release(sk);
 304         return ret;
 305
 306 read_error:
 307         return ret;
 308 }
 309
 310
 311 /* Copied from unix_stream_wait_data, identical except for lock call. */
 312 static long caif_stream_data_wait(struct sock *sk, long timeo)
 313 {
 314         DEFINE_WAIT(wait);
 315         lock_sock(sk);
 316
 317         for (;;) {
 318                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 319
 320                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 321                         sk->sk_err ||
 322                         sk->sk_state != CAIF_CONNECTED ||
 323                         sock_flag(sk, SOCK_DEAD) ||
 324                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 325                         signal_pending(current) ||
 326                         !timeo)
 327                         break;
 328
 329                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 330                 release_sock(sk);
 331                 timeo = schedule_timeout(timeo);
 332                 lock_sock(sk);
 333
 334                 if (sock_flag(sk, SOCK_DEAD))
 335                         break;
 336
 337                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 338         }
 339
 340         finish_wait(sk_sleep(sk), &wait);
 341         release_sock(sk);
 342         return timeo;
 343 }
 344
 345
 346 /*
 347  * Copied from unix_stream_recvmsg, but removed credit checks,
 348  * changed locking calls, changed address handling.
 349  */
 350 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 351                                size_t size, int flags)
 352 {
 353         struct sock *sk = sock->sk;
 354         int copied = 0;
 355         int target;
 356         int err = 0;
 357         long timeo;
 358
 359         err = -EOPNOTSUPP;
 360         if (flags&MSG_OOB)
 361                 goto out;
 362
 363         /*
 364          * Lock the socket to prevent queue disordering
 365          * while sleeps in memcpy_tomsg
 366          */
 367         err = -EAGAIN;
 368         if (sk->sk_state == CAIF_CONNECTING)
 369                 goto out;
 370
 371         caif_read_lock(sk);
 372         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 373         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 374
 375         do {
 376                 int chunk;
 377                 struct sk_buff *skb;
 378
 379                 lock_sock(sk);
 380                 if (sock_flag(sk, SOCK_DEAD)) {
 381                         err = -ECONNRESET;
 382                         goto unlock;
 383                 }
 384                 skb = skb_dequeue(&sk->sk_receive_queue);
 385                 caif_check_flow_release(sk);
 386
 387                 if (skb == NULL) {
 388                         if (copied >= target)
 389                                 goto unlock;
 390                         /*
 391                          *      POSIX 1003.1g mandates this order.
 392                          */
 393                         err = sock_error(sk);
 394                         if (err)
 395                                 goto unlock;
 396                         err = -ECONNRESET;
 397                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 398                                 goto unlock;
 399
 400                         err = -EPIPE;
 401                         if (sk->sk_state != CAIF_CONNECTED)
 402                                 goto unlock;
 403                         if (sock_flag(sk, SOCK_DEAD))
 404                                 goto unlock;
 405
 406                         release_sock(sk);
 407
 408                         err = -EAGAIN;
 409                         if (!timeo)
 410                                 break;
 411
 412                         caif_read_unlock(sk);
 413
 414                         timeo = caif_stream_data_wait(sk, timeo);
 415
 416                         if (signal_pending(current)) {
 417                                 err = sock_intr_errno(timeo);
 418                                 goto out;
 419                         }
 420                         caif_read_lock(sk);
 421                         continue;
 422 unlock:
 423                         release_sock(sk);
 424                         break;
 425                 }
 426                 release_sock(sk);
 427                 chunk = min_t(unsigned int, skb->len, size);
 428                 if (memcpy_to_msg(msg, skb->data, chunk)) {
 429                         skb_queue_head(&sk->sk_receive_queue, skb);
 430                         if (copied == 0)
 431                                 copied = -EFAULT;
 432                         break;
 433                 }
 434                 copied += chunk;
 435                 size -= chunk;
 436
 437                 /* Mark read part of skb as used */
 438                 if (!(flags & MSG_PEEK)) {
 439                         skb_pull(skb, chunk);
 440
 441                         /* put the skb back if we didn't use it up. */
 442                         if (skb->len) {
 443                                 skb_queue_head(&sk->sk_receive_queue, skb);
 444                                 break;
 445                         }
 446                         kfree_skb(skb);
 447
 448                 } else {
 449                         /*
 450                          * It is questionable, see note in unix_dgram_recvmsg.
 451                          */
 452                         /* put message back and return */
 453                         skb_queue_head(&sk->sk_receive_queue, skb);
 454                         break;
 455                 }
 456         } while (size);
 457         caif_read_unlock(sk);
 458
 459 out:
 460         return copied ? : err;
 461 }
 462
 463 /*
 464  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 465  * CAIF flow-on and sock_writable.
 466  */
 467 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 468                                   int wait_writeable, long timeo, int *err)
 469 {
 470         struct sock *sk = &cf_sk->sk;
 471         DEFINE_WAIT(wait);
 472         for (;;) {
 473                 *err = 0;
 474                 if (tx_flow_is_on(cf_sk) &&
 475                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 476                         break;
 477                 *err = -ETIMEDOUT;
 478                 if (!timeo)
 479                         break;
 480                 *err = -ERESTARTSYS;
 481                 if (signal_pending(current))
 482                         break;
 483                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 484                 *err = -ECONNRESET;
 485                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 486                         break;
 487                 *err = -sk->sk_err;
 488                 if (sk->sk_err)
 489                         break;
 490                 *err = -EPIPE;
 491                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 492                         break;
 493                 timeo = schedule_timeout(timeo);
 494         }
 495         finish_wait(sk_sleep(sk), &wait);
 496         return timeo;
 497 }
 498
 499 /*
 500  * Transmit a SKB. The device may temporarily request re-transmission
 501  * by returning EAGAIN.
 502  */
 503 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 504                         int noblock, long timeo)
 505 {
 506         struct cfpkt *pkt;
 507
 508         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 509         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 510         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 511
 512         if (cf_sk->layer.dn == NULL) {
 513                 kfree_skb(skb);
 514                 return -EINVAL;
 515         }
 516
 517         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 518 }
 519
 520 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 521 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
 522                                size_t len)
 523 {
 524         struct sock *sk = sock->sk;
 525         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 526         int buffer_size;
 527         int ret = 0;
 528         struct sk_buff *skb = NULL;
 529         int noblock;
 530         long timeo;
 531         caif_assert(cf_sk);
 532         ret = sock_error(sk);
 533         if (ret)
 534                 goto err;
 535
 536         ret = -EOPNOTSUPP;
 537         if (msg->msg_flags&MSG_OOB)
 538                 goto err;
 539
 540         ret = -EOPNOTSUPP;
 541         if (msg->msg_namelen)
 542                 goto err;
 543
 544         ret = -EINVAL;
 545         if (unlikely(msg->msg_iter.iov->iov_base == NULL))
 546                 goto err;
 547         noblock = msg->msg_flags & MSG_DONTWAIT;
 548
 549         timeo = sock_sndtimeo(sk, noblock);
 550         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 551                                 1, timeo, &ret);
 552
 553         if (ret)
 554                 goto err;
 555         ret = -EPIPE;
 556         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 557                 sock_flag(sk, SOCK_DEAD) ||
 558                 (sk->sk_shutdown & RCV_SHUTDOWN))
 559                 goto err;
 560
 561         /* Error if trying to write more than maximum frame size. */
 562         ret = -EMSGSIZE;
 563         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 564                 goto err;
 565
 566         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 567
 568         ret = -ENOMEM;
 569         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 570
 571         if (!skb || skb_tailroom(skb) < buffer_size)
 572                 goto err;
 573
 574         skb_reserve(skb, cf_sk->headroom);
 575
 576         ret = memcpy_from_msg(skb_put(skb, len), msg, len);
 577
 578         if (ret)
 579                 goto err;
 580         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 581         if (ret < 0)
 582                 /* skb is already freed */
 583                 return ret;
 584
 585         return len;
 586 err:
 587         kfree_skb(skb);
 588         return ret;
 589 }
 590
 591 /*
 592  * Copied from unix_stream_sendmsg and adapted to CAIF:
 593  * Changed removed permission handling and added waiting for flow on
 594  * and other minor adaptations.
 595  */
 596 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 597                                size_t len)
 598 {
 599         struct sock *sk = sock->sk;
 600         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 601         int err, size;
 602         struct sk_buff *skb;
 603         int sent = 0;
 604         long timeo;
 605
 606         err = -EOPNOTSUPP;
 607         if (unlikely(msg->msg_flags&MSG_OOB))
 608                 goto out_err;
 609
 610         if (unlikely(msg->msg_namelen))
 611                 goto out_err;
 612
 613         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 614         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 615
 616         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 617                 goto pipe_err;
 618
 619         while (sent < len) {
 620
 621                 size = len-sent;
 622
 623                 if (size > cf_sk->maxframe)
 624                         size = cf_sk->maxframe;
 625
 626                 /* If size is more than half of sndbuf, chop up message */
 627                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 628                         size = (sk->sk_sndbuf >> 1) - 64;
 629
 630                 if (size > SKB_MAX_ALLOC)
 631                         size = SKB_MAX_ALLOC;
 632
 633                 skb = sock_alloc_send_skb(sk,
 634                                         size + cf_sk->headroom +
 635                                         cf_sk->tailroom,
 636                                         msg->msg_flags&MSG_DONTWAIT,
 637                                         &err);
 638                 if (skb == NULL)
 639                         goto out_err;
 640
 641                 skb_reserve(skb, cf_sk->headroom);
 642                 /*
 643                  *      If you pass two values to the sock_alloc_send_skb
 644                  *      it tries to grab the large buffer with GFP_NOFS
 645                  *      (which can fail easily), and if it fails grab the
 646                  *      fallback size buffer which is under a page and will
 647                  *      succeed. [Alan]
 648                  */
 649                 size = min_t(int, size, skb_tailroom(skb));
 650
 651                 err = memcpy_from_msg(skb_put(skb, size), msg, size);
 652                 if (err) {
 653                         kfree_skb(skb);
 654                         goto out_err;
 655                 }
 656                 err = transmit_skb(skb, cf_sk,
 657                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 658                 if (err < 0)
 659                         /* skb is already freed */
 660                         goto pipe_err;
 661
 662                 sent += size;
 663         }
 664
 665         return sent;
 666
 667 pipe_err:
 668         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 669                 send_sig(SIGPIPE, current, 0);
 670         err = -EPIPE;
 671 out_err:
 672         return sent ? : err;
 673 }
 674
 675 static int setsockopt(struct socket *sock,
 676                       int lvl, int opt, char __user *ov, unsigned int ol)
 677 {
 678         struct sock *sk = sock->sk;
 679         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 680         int linksel;
 681
 682         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 683                 return -ENOPROTOOPT;
 684
 685         switch (opt) {
 686         case CAIFSO_LINK_SELECT:
 687                 if (ol < sizeof(int))
 688                         return -EINVAL;
 689                 if (lvl != SOL_CAIF)
 690                         goto bad_sol;
 691                 if (copy_from_user(&linksel, ov, sizeof(int)))
 692                         return -EINVAL;
 693                 lock_sock(&(cf_sk->sk));
 694                 cf_sk->conn_req.link_selector = linksel;
 695                 release_sock(&cf_sk->sk);
 696                 return 0;
 697
 698         case CAIFSO_REQ_PARAM:
 699                 if (lvl != SOL_CAIF)
 700                         goto bad_sol;
 701                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 702                         return -ENOPROTOOPT;
 703                 lock_sock(&(cf_sk->sk));
 704                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 705                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 706                         release_sock(&cf_sk->sk);
 707                         return -EINVAL;
 708                 }
 709                 cf_sk->conn_req.param.size = ol;
 710                 release_sock(&cf_sk->sk);
 711                 return 0;
 712
 713         default:
 714                 return -ENOPROTOOPT;
 715         }
 716
 717         return 0;
 718 bad_sol:
 719         return -ENOPROTOOPT;
 720
 721 }
 722
 723 /*
 724  * caif_connect() - Connect a CAIF Socket
 725  * Copied and modified af_irda.c:irda_connect().
 726  *
 727  * Note : by consulting "errno", the user space caller may learn the cause
 728  * of the failure. Most of them are visible in the function, others may come
 729  * from subroutines called and are listed here :
 730  *  o -EAFNOSUPPORT: bad socket family or type.
 731  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 732  *  o -EINVAL: bad socket address, or CAIF link type
 733  *  o -ECONNREFUSED: remote end refused the connection.
 734  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 735  *  o -EISCONN: already connected.
 736  *  o -ETIMEDOUT: Connection timed out (send timeout)
 737  *  o -ENODEV: No link layer to send request
 738  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 739  *  o -ENOMEM: Out of memory
 740  *
 741  *  State Strategy:
 742  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 743  *      caif_ctrl_cb.
 744  *  o sock->state: holds the SS_* socket state and is updated by connect and
 745  *      disconnect.
 746  */
 747 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 748                         int addr_len, int flags)
 749 {
 750         struct sock *sk = sock->sk;
 751         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 752         long timeo;
 753         int err;
 754         int ifindex, headroom, tailroom;
 755         unsigned int mtu;
 756         struct net_device *dev;
 757
 758         lock_sock(sk);
 759
 760         err = -EAFNOSUPPORT;
 761         if (uaddr->sa_family != AF_CAIF)
 762                 goto out;
 763
 764         switch (sock->state) {
 765         case SS_UNCONNECTED:
 766                 /* Normal case, a fresh connect */
 767                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 768                 break;
 769         case SS_CONNECTING:
 770                 switch (sk->sk_state) {
 771                 case CAIF_CONNECTED:
 772                         sock->state = SS_CONNECTED;
 773                         err = -EISCONN;
 774                         goto out;
 775                 case CAIF_DISCONNECTED:
 776                         /* Reconnect allowed */
 777                         break;
 778                 case CAIF_CONNECTING:
 779                         err = -EALREADY;
 780                         if (flags & O_NONBLOCK)
 781                                 goto out;
 782                         goto wait_connect;
 783                 }
 784                 break;
 785         case SS_CONNECTED:
 786                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 787                                 sk->sk_state == CAIF_DISCONNECTED);
 788                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 789                         /* Allow re-connect after SHUTDOWN_IND */
 790                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 791                         caif_free_client(&cf_sk->layer);
 792                         break;
 793                 }
 794                 /* No reconnect on a seqpacket socket */
 795                 err = -EISCONN;
 796                 goto out;
 797         case SS_DISCONNECTING:
 798         case SS_FREE:
 799                 caif_assert(1); /*Should never happen */
 800                 break;
 801         }
 802         sk->sk_state = CAIF_DISCONNECTED;
 803         sock->state = SS_UNCONNECTED;
 804         sk_stream_kill_queues(&cf_sk->sk);
 805
 806         err = -EINVAL;
 807         if (addr_len != sizeof(struct sockaddr_caif))
 808                 goto out;
 809
 810         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 811                 sizeof(struct sockaddr_caif));
 812
 813         /* Move to connecting socket, start sending Connect Requests */
 814         sock->state = SS_CONNECTING;
 815         sk->sk_state = CAIF_CONNECTING;
 816
 817         /* Check priority value comming from socket */
 818         /* if priority value is out of range it will be ajusted */
 819         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 820                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 821         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 822                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 823         else
 824                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 825
 826         /*ifindex = id of the interface.*/
 827         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 828
 829         cf_sk->layer.receive = caif_sktrecv_cb;
 830
 831         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 832                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 833
 834         if (err < 0) {
 835                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 836                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 837                 goto out;
 838         }
 839
 840         err = -ENODEV;
 841         rcu_read_lock();
 842         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 843         if (!dev) {
 844                 rcu_read_unlock();
 845                 goto out;
 846         }
 847         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 848         mtu = dev->mtu;
 849         rcu_read_unlock();
 850
 851         cf_sk->tailroom = tailroom;
 852         cf_sk->maxframe = mtu - (headroom + tailroom);
 853         if (cf_sk->maxframe < 1) {
 854                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 855                 err = -ENODEV;
 856                 goto out;
 857         }
 858
 859         err = -EINPROGRESS;
 860 wait_connect:
 861
 862         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 863                 goto out;
 864
 865         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 866
 867         release_sock(sk);
 868         err = -ERESTARTSYS;
 869         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 870                         sk->sk_state != CAIF_CONNECTING,
 871                         timeo);
 872         lock_sock(sk);
 873         if (timeo < 0)
 874                 goto out; /* -ERESTARTSYS */
 875
 876         err = -ETIMEDOUT;
 877         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 878                 goto out;
 879         if (sk->sk_state != CAIF_CONNECTED) {
 880                 sock->state = SS_UNCONNECTED;
 881                 err = sock_error(sk);
 882                 if (!err)
 883                         err = -ECONNREFUSED;
 884                 goto out;
 885         }
 886         sock->state = SS_CONNECTED;
 887         err = 0;
 888 out:
 889         release_sock(sk);
 890         return err;
 891 }
 892
 893 /*
 894  * caif_release() - Disconnect a CAIF Socket
 895  * Copied and modified af_irda.c:irda_release().
 896  */
 897 static int caif_release(struct socket *sock)
 898 {
 899         struct sock *sk = sock->sk;
 900         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 901
 902         if (!sk)
 903                 return 0;
 904
 905         set_tx_flow_off(cf_sk);
 906
 907         /*
 908          * Ensure that packets are not queued after this point in time.
 909          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 910          * this ensures no packets when sock is dead.
 911          */
 912         spin_lock_bh(&sk->sk_receive_queue.lock);
 913         sock_set_flag(sk, SOCK_DEAD);
 914         spin_unlock_bh(&sk->sk_receive_queue.lock);
 915         sock->sk = NULL;
 916
 917         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 918         debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 919
 920         lock_sock(&(cf_sk->sk));
 921         sk->sk_state = CAIF_DISCONNECTED;
 922         sk->sk_shutdown = SHUTDOWN_MASK;
 923
 924         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 925         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 926         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 927
 928         sock_orphan(sk);
 929         sk_stream_kill_queues(&cf_sk->sk);
 930         release_sock(sk);
 931         sock_put(sk);
 932         return 0;
 933 }
 934
 935 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 936 static unsigned int caif_poll(struct file *file,
 937                               struct socket *sock, poll_table *wait)
 938 {
 939         struct sock *sk = sock->sk;
 940         unsigned int mask;
 941         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 942
 943         sock_poll_wait(file, sk_sleep(sk), wait);
 944         mask = 0;
 945
 946         /* exceptional events? */
 947         if (sk->sk_err)
 948                 mask |= POLLERR;
 949         if (sk->sk_shutdown == SHUTDOWN_MASK)
 950                 mask |= POLLHUP;
 951         if (sk->sk_shutdown & RCV_SHUTDOWN)
 952                 mask |= POLLRDHUP;
 953
 954         /* readable? */
 955         if (!skb_queue_empty(&sk->sk_receive_queue) ||
 956                 (sk->sk_shutdown & RCV_SHUTDOWN))
 957                 mask |= POLLIN | POLLRDNORM;
 958
 959         /*
 960          * we set writable also when the other side has shut down the
 961          * connection. This prevents stuck sockets.
 962          */
 963         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 964                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 965
 966         return mask;
 967 }
 968
 969 static const struct proto_ops caif_seqpacket_ops = {
 970         .family = PF_CAIF,
 971         .owner = THIS_MODULE,
 972         .release = caif_release,
 973         .bind = sock_no_bind,
 974         .connect = caif_connect,
 975         .socketpair = sock_no_socketpair,
 976         .accept = sock_no_accept,
 977         .getname = sock_no_getname,
 978         .poll = caif_poll,
 979         .ioctl = sock_no_ioctl,
 980         .listen = sock_no_listen,
 981         .shutdown = sock_no_shutdown,
 982         .setsockopt = setsockopt,
 983         .getsockopt = sock_no_getsockopt,
 984         .sendmsg = caif_seqpkt_sendmsg,
 985         .recvmsg = caif_seqpkt_recvmsg,
 986         .mmap = sock_no_mmap,
 987         .sendpage = sock_no_sendpage,
 988 };
 989
 990 static const struct proto_ops caif_stream_ops = {
 991         .family = PF_CAIF,
 992         .owner = THIS_MODULE,
 993         .release = caif_release,
 994         .bind = sock_no_bind,
 995         .connect = caif_connect,
 996         .socketpair = sock_no_socketpair,
 997         .accept = sock_no_accept,
 998         .getname = sock_no_getname,
 999         .poll = caif_poll,
1000         .ioctl = sock_no_ioctl,
1001         .listen = sock_no_listen,
1002         .shutdown = sock_no_shutdown,
1003         .setsockopt = setsockopt,
1004         .getsockopt = sock_no_getsockopt,
1005         .sendmsg = caif_stream_sendmsg,
1006         .recvmsg = caif_stream_recvmsg,
1007         .mmap = sock_no_mmap,
1008         .sendpage = sock_no_sendpage,
1009 };
1010
1011 /* This function is called when a socket is finally destroyed. */
1012 static void caif_sock_destructor(struct sock *sk)
1013 {
1014         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1015         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1016         caif_assert(sk_unhashed(sk));
1017         caif_assert(!sk->sk_socket);
1018         if (!sock_flag(sk, SOCK_DEAD)) {
1019                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1020                 return;
1021         }
1022         sk_stream_kill_queues(&cf_sk->sk);
1023         caif_free_client(&cf_sk->layer);
1024 }
1025
1026 static int caif_create(struct net *net, struct socket *sock, int protocol,
1027                        int kern)
1028 {
1029         struct sock *sk = NULL;
1030         struct caifsock *cf_sk = NULL;
1031         static struct proto prot = {.name = "PF_CAIF",
1032                 .owner = THIS_MODULE,
1033                 .obj_size = sizeof(struct caifsock),
1034         };
1035
1036         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1037                 return -EPERM;
1038         /*
1039          * The sock->type specifies the socket type to use.
1040          * The CAIF socket is a packet stream in the sense
1041          * that it is packet based. CAIF trusts the reliability
1042          * of the link, no resending is implemented.
1043          */
1044         if (sock->type == SOCK_SEQPACKET)
1045                 sock->ops = &caif_seqpacket_ops;
1046         else if (sock->type == SOCK_STREAM)
1047                 sock->ops = &caif_stream_ops;
1048         else
1049                 return -ESOCKTNOSUPPORT;
1050
1051         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1052                 return -EPROTONOSUPPORT;
1053         /*
1054          * Set the socket state to unconnected.  The socket state
1055          * is really not used at all in the net/core or socket.c but the
1056          * initialization makes sure that sock->state is not uninitialized.
1057          */
1058         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1059         if (!sk)
1060                 return -ENOMEM;
1061
1062         cf_sk = container_of(sk, struct caifsock, sk);
1063
1064         /* Store the protocol */
1065         sk->sk_protocol = (unsigned char) protocol;
1066
1067         /* Initialize default priority for well-known cases */
1068         switch (protocol) {
1069         case CAIFPROTO_AT:
1070                 sk->sk_priority = TC_PRIO_CONTROL;
1071                 break;
1072         case CAIFPROTO_RFM:
1073                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1074                 break;
1075         default:
1076                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1077         }
1078
1079         /*
1080          * Lock in order to try to stop someone from opening the socket
1081          * too early.
1082          */
1083         lock_sock(&(cf_sk->sk));
1084
1085         /* Initialize the nozero default sock structure data. */
1086         sock_init_data(sock, sk);
1087         sk->sk_destruct = caif_sock_destructor;
1088
1089         mutex_init(&cf_sk->readlock); /* single task reading lock */
1090         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1091         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1092         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1093
1094         set_tx_flow_off(cf_sk);
1095         set_rx_flow_on(cf_sk);
1096
1097         /* Set default options on configuration */
1098         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1099         cf_sk->conn_req.protocol = protocol;
1100         release_sock(&cf_sk->sk);
1101         return 0;
1102 }
1103
1104
1105 static struct net_proto_family caif_family_ops = {
1106         .family = PF_CAIF,
1107         .create = caif_create,
1108         .owner = THIS_MODULE,
1109 };
1110
1111 static int __init caif_sktinit_module(void)
1112 {
1113         int err = sock_register(&caif_family_ops);
1114         if (!err)
1115                 return err;
1116         return 0;
1117 }
1118
1119 static void __exit caif_sktexit_module(void)
1120 {
1121         sock_unregister(PF_CAIF);
1122 }
1123 module_init(caif_sktinit_module);
1124 module_exit(caif_sktexit_module);