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