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