net/caif/caif_socket.c

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