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