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         int skb_len;
 128         unsigned long flags;
 129         struct sk_buff_head *list = &sk->sk_receive_queue;
 130         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 131
 132         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 133                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 134                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 135                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
 136                                     sk_rcvbuf_lowwater(cf_sk));
 137                 set_rx_flow_off(cf_sk);
 138                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 139         }
 140
 141         err = sk_filter(sk, skb);
 142         if (err)
 143                 return err;
 144         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 145                 set_rx_flow_off(cf_sk);
 146                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 147                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 148         }
 149         skb->dev = NULL;
 150         skb_set_owner_r(skb, sk);
 151         /* Cache the SKB length before we tack it onto the receive
 152          * queue. Once it is added it no longer belongs to us and
 153          * may be freed by other threads of control pulling packets
 154          * from the queue.
 155          */
 156         skb_len = skb->len;
 157         spin_lock_irqsave(&list->lock, flags);
 158         if (!sock_flag(sk, SOCK_DEAD))
 159                 __skb_queue_tail(list, skb);
 160         spin_unlock_irqrestore(&list->lock, flags);
 161
 162         if (!sock_flag(sk, SOCK_DEAD))
 163                 sk->sk_data_ready(sk, skb_len);
 164         else
 165                 kfree_skb(skb);
 166         return 0;
 167 }
 168
 169 /* Packet Receive Callback function called from CAIF Stack */
 170 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 171 {
 172         struct caifsock *cf_sk;
 173         struct sk_buff *skb;
 174
 175         cf_sk = container_of(layr, struct caifsock, layer);
 176         skb = cfpkt_tonative(pkt);
 177
 178         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 179                 kfree_skb(skb);
 180                 return 0;
 181         }
 182         caif_queue_rcv_skb(&cf_sk->sk, skb);
 183         return 0;
 184 }
 185
 186 static void cfsk_hold(struct cflayer *layr)
 187 {
 188         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 189         sock_hold(&cf_sk->sk);
 190 }
 191
 192 static void cfsk_put(struct cflayer *layr)
 193 {
 194         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 195         sock_put(&cf_sk->sk);
 196 }
 197
 198 /* Packet Control Callback function called from CAIF */
 199 static void caif_ctrl_cb(struct cflayer *layr,
 200                          enum caif_ctrlcmd flow,
 201                          int phyid)
 202 {
 203         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 204         switch (flow) {
 205         case CAIF_CTRLCMD_FLOW_ON_IND:
 206                 /* OK from modem to start sending again */
 207                 set_tx_flow_on(cf_sk);
 208                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 209                 break;
 210
 211         case CAIF_CTRLCMD_FLOW_OFF_IND:
 212                 /* Modem asks us to shut up */
 213                 set_tx_flow_off(cf_sk);
 214                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 215                 break;
 216
 217         case CAIF_CTRLCMD_INIT_RSP:
 218                 /* We're now connected */
 219                 caif_client_register_refcnt(&cf_sk->layer,
 220                                                 cfsk_hold, cfsk_put);
 221                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 222                 set_tx_flow_on(cf_sk);
 223                 cf_sk->sk.sk_shutdown = 0;
 224                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 225                 break;
 226
 227         case CAIF_CTRLCMD_DEINIT_RSP:
 228                 /* We're now disconnected */
 229                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 230                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 231                 break;
 232
 233         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 234                 /* Connect request failed */
 235                 cf_sk->sk.sk_err = ECONNREFUSED;
 236                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 237                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 238                 /*
 239                  * Socket "standards" seems to require POLLOUT to
 240                  * be set at connect failure.
 241                  */
 242                 set_tx_flow_on(cf_sk);
 243                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 244                 break;
 245
 246         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 247                 /* Modem has closed this connection, or device is down. */
 248                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 249                 cf_sk->sk.sk_err = ECONNRESET;
 250                 set_rx_flow_on(cf_sk);
 251                 cf_sk->sk.sk_error_report(&cf_sk->sk);
 252                 break;
 253
 254         default:
 255                 pr_debug("Unexpected flow command %d\n", flow);
 256         }
 257 }
 258
 259 static void caif_check_flow_release(struct sock *sk)
 260 {
 261         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 262
 263         if (rx_flow_is_on(cf_sk))
 264                 return;
 265
 266         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 267                         set_rx_flow_on(cf_sk);
 268                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 269         }
 270 }
 271
 272 /*
 273  * Copied from unix_dgram_recvmsg, but removed credit checks,
 274  * changed locking, address handling and added MSG_TRUNC.
 275  */
 276 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
 277                                struct msghdr *m, size_t len, int flags)
 278
 279 {
 280         struct sock *sk = sock->sk;
 281         struct sk_buff *skb;
 282         int ret;
 283         int copylen;
 284
 285         ret = -EOPNOTSUPP;
 286         if (flags & MSG_OOB)
 287                 goto read_error;
 288
 289         skb = skb_recv_datagram(sk, flags, 0 , &ret);
 290         if (!skb)
 291                 goto read_error;
 292         copylen = skb->len;
 293         if (len < copylen) {
 294                 m->msg_flags |= MSG_TRUNC;
 295                 copylen = len;
 296         }
 297
 298         ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
 299         if (ret)
 300                 goto out_free;
 301
 302         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 303 out_free:
 304         skb_free_datagram(sk, skb);
 305         caif_check_flow_release(sk);
 306         return ret;
 307
 308 read_error:
 309         return ret;
 310 }
 311
 312
 313 /* Copied from unix_stream_wait_data, identical except for lock call. */
 314 static long caif_stream_data_wait(struct sock *sk, long timeo)
 315 {
 316         DEFINE_WAIT(wait);
 317         lock_sock(sk);
 318
 319         for (;;) {
 320                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 321
 322                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 323                         sk->sk_err ||
 324                         sk->sk_state != CAIF_CONNECTED ||
 325                         sock_flag(sk, SOCK_DEAD) ||
 326                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 327                         signal_pending(current) ||
 328                         !timeo)
 329                         break;
 330
 331                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 332                 release_sock(sk);
 333                 timeo = schedule_timeout(timeo);
 334                 lock_sock(sk);
 335
 336                 if (sock_flag(sk, SOCK_DEAD))
 337                         break;
 338
 339                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 340         }
 341
 342         finish_wait(sk_sleep(sk), &wait);
 343         release_sock(sk);
 344         return timeo;
 345 }
 346
 347
 348 /*
 349  * Copied from unix_stream_recvmsg, but removed credit checks,
 350  * changed locking calls, changed address handling.
 351  */
 352 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 353                                struct msghdr *msg, size_t size,
 354                                int flags)
 355 {
 356         struct sock *sk = sock->sk;
 357         int copied = 0;
 358         int target;
 359         int err = 0;
 360         long timeo;
 361
 362         err = -EOPNOTSUPP;
 363         if (flags&MSG_OOB)
 364                 goto out;
 365
 366         /*
 367          * Lock the socket to prevent queue disordering
 368          * while sleeps in memcpy_tomsg
 369          */
 370         err = -EAGAIN;
 371         if (sk->sk_state == CAIF_CONNECTING)
 372                 goto out;
 373
 374         caif_read_lock(sk);
 375         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 376         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 377
 378         do {
 379                 int chunk;
 380                 struct sk_buff *skb;
 381
 382                 lock_sock(sk);
 383                 if (sock_flag(sk, SOCK_DEAD)) {
 384                         err = -ECONNRESET;
 385                         goto unlock;
 386                 }
 387                 skb = skb_dequeue(&sk->sk_receive_queue);
 388                 caif_check_flow_release(sk);
 389
 390                 if (skb == NULL) {
 391                         if (copied >= target)
 392                                 goto unlock;
 393                         /*
 394                          *      POSIX 1003.1g mandates this order.
 395                          */
 396                         err = sock_error(sk);
 397                         if (err)
 398                                 goto unlock;
 399                         err = -ECONNRESET;
 400                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 401                                 goto unlock;
 402
 403                         err = -EPIPE;
 404                         if (sk->sk_state != CAIF_CONNECTED)
 405                                 goto unlock;
 406                         if (sock_flag(sk, SOCK_DEAD))
 407                                 goto unlock;
 408
 409                         release_sock(sk);
 410
 411                         err = -EAGAIN;
 412                         if (!timeo)
 413                                 break;
 414
 415                         caif_read_unlock(sk);
 416
 417                         timeo = caif_stream_data_wait(sk, timeo);
 418
 419                         if (signal_pending(current)) {
 420                                 err = sock_intr_errno(timeo);
 421                                 goto out;
 422                         }
 423                         caif_read_lock(sk);
 424                         continue;
 425 unlock:
 426                         release_sock(sk);
 427                         break;
 428                 }
 429                 release_sock(sk);
 430                 chunk = min_t(unsigned int, skb->len, size);
 431                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
 432                         skb_queue_head(&sk->sk_receive_queue, skb);
 433                         if (copied == 0)
 434                                 copied = -EFAULT;
 435                         break;
 436                 }
 437                 copied += chunk;
 438                 size -= chunk;
 439
 440                 /* Mark read part of skb as used */
 441                 if (!(flags & MSG_PEEK)) {
 442                         skb_pull(skb, chunk);
 443
 444                         /* put the skb back if we didn't use it up. */
 445                         if (skb->len) {
 446                                 skb_queue_head(&sk->sk_receive_queue, skb);
 447                                 break;
 448                         }
 449                         kfree_skb(skb);
 450
 451                 } else {
 452                         /*
 453                          * It is questionable, see note in unix_dgram_recvmsg.
 454                          */
 455                         /* put message back and return */
 456                         skb_queue_head(&sk->sk_receive_queue, skb);
 457                         break;
 458                 }
 459         } while (size);
 460         caif_read_unlock(sk);
 461
 462 out:
 463         return copied ? : err;
 464 }
 465
 466 /*
 467  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 468  * CAIF flow-on and sock_writable.
 469  */
 470 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 471                                   int wait_writeable, long timeo, int *err)
 472 {
 473         struct sock *sk = &cf_sk->sk;
 474         DEFINE_WAIT(wait);
 475         for (;;) {
 476                 *err = 0;
 477                 if (tx_flow_is_on(cf_sk) &&
 478                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 479                         break;
 480                 *err = -ETIMEDOUT;
 481                 if (!timeo)
 482                         break;
 483                 *err = -ERESTARTSYS;
 484                 if (signal_pending(current))
 485                         break;
 486                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 487                 *err = -ECONNRESET;
 488                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 489                         break;
 490                 *err = -sk->sk_err;
 491                 if (sk->sk_err)
 492                         break;
 493                 *err = -EPIPE;
 494                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 495                         break;
 496                 timeo = schedule_timeout(timeo);
 497         }
 498         finish_wait(sk_sleep(sk), &wait);
 499         return timeo;
 500 }
 501
 502 /*
 503  * Transmit a SKB. The device may temporarily request re-transmission
 504  * by returning EAGAIN.
 505  */
 506 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 507                         int noblock, long timeo)
 508 {
 509         struct cfpkt *pkt;
 510
 511         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 512         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 513         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 514
 515         if (cf_sk->layer.dn == NULL) {
 516                 kfree_skb(skb);
 517                 return -EINVAL;
 518         }
 519
 520         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 521 }
 522
 523 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 524 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 525                                struct msghdr *msg, size_t len)
 526 {
 527         struct sock *sk = sock->sk;
 528         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 529         int buffer_size;
 530         int ret = 0;
 531         struct sk_buff *skb = NULL;
 532         int noblock;
 533         long timeo;
 534         caif_assert(cf_sk);
 535         ret = sock_error(sk);
 536         if (ret)
 537                 goto err;
 538
 539         ret = -EOPNOTSUPP;
 540         if (msg->msg_flags&MSG_OOB)
 541                 goto err;
 542
 543         ret = -EOPNOTSUPP;
 544         if (msg->msg_namelen)
 545                 goto err;
 546
 547         ret = -EINVAL;
 548         if (unlikely(msg->msg_iov->iov_base == NULL))
 549                 goto err;
 550         noblock = msg->msg_flags & MSG_DONTWAIT;
 551
 552         timeo = sock_sndtimeo(sk, noblock);
 553         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 554                                 1, timeo, &ret);
 555
 556         if (ret)
 557                 goto err;
 558         ret = -EPIPE;
 559         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 560                 sock_flag(sk, SOCK_DEAD) ||
 561                 (sk->sk_shutdown & RCV_SHUTDOWN))
 562                 goto err;
 563
 564         /* Error if trying to write more than maximum frame size. */
 565         ret = -EMSGSIZE;
 566         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 567                 goto err;
 568
 569         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 570
 571         ret = -ENOMEM;
 572         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 573
 574         if (!skb || skb_tailroom(skb) < buffer_size)
 575                 goto err;
 576
 577         skb_reserve(skb, cf_sk->headroom);
 578
 579         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 580
 581         if (ret)
 582                 goto err;
 583         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 584         if (ret < 0)
 585                 /* skb is already freed */
 586                 return ret;
 587
 588         return len;
 589 err:
 590         kfree_skb(skb);
 591         return ret;
 592 }
 593
 594 /*
 595  * Copied from unix_stream_sendmsg and adapted to CAIF:
 596  * Changed removed permission handling and added waiting for flow on
 597  * and other minor adaptations.
 598  */
 599 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 600                                struct msghdr *msg, size_t len)
 601 {
 602         struct sock *sk = sock->sk;
 603         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 604         int err, size;
 605         struct sk_buff *skb;
 606         int sent = 0;
 607         long timeo;
 608
 609         err = -EOPNOTSUPP;
 610         if (unlikely(msg->msg_flags&MSG_OOB))
 611                 goto out_err;
 612
 613         if (unlikely(msg->msg_namelen))
 614                 goto out_err;
 615
 616         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 617         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 618
 619         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 620                 goto pipe_err;
 621
 622         while (sent < len) {
 623
 624                 size = len-sent;
 625
 626                 if (size > cf_sk->maxframe)
 627                         size = cf_sk->maxframe;
 628
 629                 /* If size is more than half of sndbuf, chop up message */
 630                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 631                         size = (sk->sk_sndbuf >> 1) - 64;
 632
 633                 if (size > SKB_MAX_ALLOC)
 634                         size = SKB_MAX_ALLOC;
 635
 636                 skb = sock_alloc_send_skb(sk,
 637                                         size + cf_sk->headroom +
 638                                         cf_sk->tailroom,
 639                                         msg->msg_flags&MSG_DONTWAIT,
 640                                         &err);
 641                 if (skb == NULL)
 642                         goto out_err;
 643
 644                 skb_reserve(skb, cf_sk->headroom);
 645                 /*
 646                  *      If you pass two values to the sock_alloc_send_skb
 647                  *      it tries to grab the large buffer with GFP_NOFS
 648                  *      (which can fail easily), and if it fails grab the
 649                  *      fallback size buffer which is under a page and will
 650                  *      succeed. [Alan]
 651                  */
 652                 size = min_t(int, size, skb_tailroom(skb));
 653
 654                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 655                 if (err) {
 656                         kfree_skb(skb);
 657                         goto out_err;
 658                 }
 659                 err = transmit_skb(skb, cf_sk,
 660                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 661                 if (err < 0)
 662                         /* skb is already freed */
 663                         goto pipe_err;
 664
 665                 sent += size;
 666         }
 667
 668         return sent;
 669
 670 pipe_err:
 671         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 672                 send_sig(SIGPIPE, current, 0);
 673         err = -EPIPE;
 674 out_err:
 675         return sent ? : err;
 676 }
 677
 678 static int setsockopt(struct socket *sock,
 679                       int lvl, int opt, char __user *ov, unsigned int ol)
 680 {
 681         struct sock *sk = sock->sk;
 682         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 683         int linksel;
 684
 685         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 686                 return -ENOPROTOOPT;
 687
 688         switch (opt) {
 689         case CAIFSO_LINK_SELECT:
 690                 if (ol < sizeof(int))
 691                         return -EINVAL;
 692                 if (lvl != SOL_CAIF)
 693                         goto bad_sol;
 694                 if (copy_from_user(&linksel, ov, sizeof(int)))
 695                         return -EINVAL;
 696                 lock_sock(&(cf_sk->sk));
 697                 cf_sk->conn_req.link_selector = linksel;
 698                 release_sock(&cf_sk->sk);
 699                 return 0;
 700
 701         case CAIFSO_REQ_PARAM:
 702                 if (lvl != SOL_CAIF)
 703                         goto bad_sol;
 704                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 705                         return -ENOPROTOOPT;
 706                 lock_sock(&(cf_sk->sk));
 707                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 708                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 709                         release_sock(&cf_sk->sk);
 710                         return -EINVAL;
 711                 }
 712                 cf_sk->conn_req.param.size = ol;
 713                 release_sock(&cf_sk->sk);
 714                 return 0;
 715
 716         default:
 717                 return -ENOPROTOOPT;
 718         }
 719
 720         return 0;
 721 bad_sol:
 722         return -ENOPROTOOPT;
 723
 724 }
 725
 726 /*
 727  * caif_connect() - Connect a CAIF Socket
 728  * Copied and modified af_irda.c:irda_connect().
 729  *
 730  * Note : by consulting "errno", the user space caller may learn the cause
 731  * of the failure. Most of them are visible in the function, others may come
 732  * from subroutines called and are listed here :
 733  *  o -EAFNOSUPPORT: bad socket family or type.
 734  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 735  *  o -EINVAL: bad socket address, or CAIF link type
 736  *  o -ECONNREFUSED: remote end refused the connection.
 737  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 738  *  o -EISCONN: already connected.
 739  *  o -ETIMEDOUT: Connection timed out (send timeout)
 740  *  o -ENODEV: No link layer to send request
 741  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 742  *  o -ENOMEM: Out of memory
 743  *
 744  *  State Strategy:
 745  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 746  *      caif_ctrl_cb.
 747  *  o sock->state: holds the SS_* socket state and is updated by connect and
 748  *      disconnect.
 749  */
 750 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 751                         int addr_len, int flags)
 752 {
 753         struct sock *sk = sock->sk;
 754         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 755         long timeo;
 756         int err;
 757         int ifindex, headroom, tailroom;
 758         unsigned int mtu;
 759         struct net_device *dev;
 760
 761         lock_sock(sk);
 762
 763         err = -EAFNOSUPPORT;
 764         if (uaddr->sa_family != AF_CAIF)
 765                 goto out;
 766
 767         switch (sock->state) {
 768         case SS_UNCONNECTED:
 769                 /* Normal case, a fresh connect */
 770                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 771                 break;
 772         case SS_CONNECTING:
 773                 switch (sk->sk_state) {
 774                 case CAIF_CONNECTED:
 775                         sock->state = SS_CONNECTED;
 776                         err = -EISCONN;
 777                         goto out;
 778                 case CAIF_DISCONNECTED:
 779                         /* Reconnect allowed */
 780                         break;
 781                 case CAIF_CONNECTING:
 782                         err = -EALREADY;
 783                         if (flags & O_NONBLOCK)
 784                                 goto out;
 785                         goto wait_connect;
 786                 }
 787                 break;
 788         case SS_CONNECTED:
 789                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 790                                 sk->sk_state == CAIF_DISCONNECTED);
 791                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 792                         /* Allow re-connect after SHUTDOWN_IND */
 793                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 794                         caif_free_client(&cf_sk->layer);
 795                         break;
 796                 }
 797                 /* No reconnect on a seqpacket socket */
 798                 err = -EISCONN;
 799                 goto out;
 800         case SS_DISCONNECTING:
 801         case SS_FREE:
 802                 caif_assert(1); /*Should never happen */
 803                 break;
 804         }
 805         sk->sk_state = CAIF_DISCONNECTED;
 806         sock->state = SS_UNCONNECTED;
 807         sk_stream_kill_queues(&cf_sk->sk);
 808
 809         err = -EINVAL;
 810         if (addr_len != sizeof(struct sockaddr_caif))
 811                 goto out;
 812
 813         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 814                 sizeof(struct sockaddr_caif));
 815
 816         /* Move to connecting socket, start sending Connect Requests */
 817         sock->state = SS_CONNECTING;
 818         sk->sk_state = CAIF_CONNECTING;
 819
 820         /* Check priority value comming from socket */
 821         /* if priority value is out of range it will be ajusted */
 822         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 823                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 824         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 825                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 826         else
 827                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 828
 829         /*ifindex = id of the interface.*/
 830         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 831
 832         cf_sk->layer.receive = caif_sktrecv_cb;
 833
 834         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 835                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 836
 837         if (err < 0) {
 838                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 839                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 840                 goto out;
 841         }
 842
 843         err = -ENODEV;
 844         rcu_read_lock();
 845         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 846         if (!dev) {
 847                 rcu_read_unlock();
 848                 goto out;
 849         }
 850         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 851         mtu = dev->mtu;
 852         rcu_read_unlock();
 853
 854         cf_sk->tailroom = tailroom;
 855         cf_sk->maxframe = mtu - (headroom + tailroom);
 856         if (cf_sk->maxframe < 1) {
 857                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 858                 err = -ENODEV;
 859                 goto out;
 860         }
 861
 862         err = -EINPROGRESS;
 863 wait_connect:
 864
 865         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 866                 goto out;
 867
 868         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 869
 870         release_sock(sk);
 871         err = -ERESTARTSYS;
 872         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 873                         sk->sk_state != CAIF_CONNECTING,
 874                         timeo);
 875         lock_sock(sk);
 876         if (timeo < 0)
 877                 goto out; /* -ERESTARTSYS */
 878
 879         err = -ETIMEDOUT;
 880         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 881                 goto out;
 882         if (sk->sk_state != CAIF_CONNECTED) {
 883                 sock->state = SS_UNCONNECTED;
 884                 err = sock_error(sk);
 885                 if (!err)
 886                         err = -ECONNREFUSED;
 887                 goto out;
 888         }
 889         sock->state = SS_CONNECTED;
 890         err = 0;
 891 out:
 892         release_sock(sk);
 893         return err;
 894 }
 895
 896 /*
 897  * caif_release() - Disconnect a CAIF Socket
 898  * Copied and modified af_irda.c:irda_release().
 899  */
 900 static int caif_release(struct socket *sock)
 901 {
 902         struct sock *sk = sock->sk;
 903         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 904
 905         if (!sk)
 906                 return 0;
 907
 908         set_tx_flow_off(cf_sk);
 909
 910         /*
 911          * Ensure that packets are not queued after this point in time.
 912          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 913          * this ensures no packets when sock is dead.
 914          */
 915         spin_lock_bh(&sk->sk_receive_queue.lock);
 916         sock_set_flag(sk, SOCK_DEAD);
 917         spin_unlock_bh(&sk->sk_receive_queue.lock);
 918         sock->sk = NULL;
 919
 920         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 921         if (cf_sk->debugfs_socket_dir != NULL)
 922                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 923
 924         lock_sock(&(cf_sk->sk));
 925         sk->sk_state = CAIF_DISCONNECTED;
 926         sk->sk_shutdown = SHUTDOWN_MASK;
 927
 928         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 929         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 930         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 931
 932         sock_orphan(sk);
 933         sk_stream_kill_queues(&cf_sk->sk);
 934         release_sock(sk);
 935         sock_put(sk);
 936         return 0;
 937 }
 938
 939 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 940 static unsigned int caif_poll(struct file *file,
 941                               struct socket *sock, poll_table *wait)
 942 {
 943         struct sock *sk = sock->sk;
 944         unsigned int mask;
 945         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 946
 947         sock_poll_wait(file, sk_sleep(sk), wait);
 948         mask = 0;
 949
 950         /* exceptional events? */
 951         if (sk->sk_err)
 952                 mask |= POLLERR;
 953         if (sk->sk_shutdown == SHUTDOWN_MASK)
 954                 mask |= POLLHUP;
 955         if (sk->sk_shutdown & RCV_SHUTDOWN)
 956                 mask |= POLLRDHUP;
 957
 958         /* readable? */
 959         if (!skb_queue_empty(&sk->sk_receive_queue) ||
 960                 (sk->sk_shutdown & RCV_SHUTDOWN))
 961                 mask |= POLLIN | POLLRDNORM;
 962
 963         /*
 964          * we set writable also when the other side has shut down the
 965          * connection. This prevents stuck sockets.
 966          */
 967         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 968                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 969
 970         return mask;
 971 }
 972
 973 static const struct proto_ops caif_seqpacket_ops = {
 974         .family = PF_CAIF,
 975         .owner = THIS_MODULE,
 976         .release = caif_release,
 977         .bind = sock_no_bind,
 978         .connect = caif_connect,
 979         .socketpair = sock_no_socketpair,
 980         .accept = sock_no_accept,
 981         .getname = sock_no_getname,
 982         .poll = caif_poll,
 983         .ioctl = sock_no_ioctl,
 984         .listen = sock_no_listen,
 985         .shutdown = sock_no_shutdown,
 986         .setsockopt = setsockopt,
 987         .getsockopt = sock_no_getsockopt,
 988         .sendmsg = caif_seqpkt_sendmsg,
 989         .recvmsg = caif_seqpkt_recvmsg,
 990         .mmap = sock_no_mmap,
 991         .sendpage = sock_no_sendpage,
 992 };
 993
 994 static const struct proto_ops caif_stream_ops = {
 995         .family = PF_CAIF,
 996         .owner = THIS_MODULE,
 997         .release = caif_release,
 998         .bind = sock_no_bind,
 999         .connect = caif_connect,
1000         .socketpair = sock_no_socketpair,
1001         .accept = sock_no_accept,
1002         .getname = sock_no_getname,
1003         .poll = caif_poll,
1004         .ioctl = sock_no_ioctl,
1005         .listen = sock_no_listen,
1006         .shutdown = sock_no_shutdown,
1007         .setsockopt = setsockopt,
1008         .getsockopt = sock_no_getsockopt,
1009         .sendmsg = caif_stream_sendmsg,
1010         .recvmsg = caif_stream_recvmsg,
1011         .mmap = sock_no_mmap,
1012         .sendpage = sock_no_sendpage,
1013 };
1014
1015 /* This function is called when a socket is finally destroyed. */
1016 static void caif_sock_destructor(struct sock *sk)
1017 {
1018         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1019         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1020         caif_assert(sk_unhashed(sk));
1021         caif_assert(!sk->sk_socket);
1022         if (!sock_flag(sk, SOCK_DEAD)) {
1023                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1024                 return;
1025         }
1026         sk_stream_kill_queues(&cf_sk->sk);
1027         caif_free_client(&cf_sk->layer);
1028 }
1029
1030 static int caif_create(struct net *net, struct socket *sock, int protocol,
1031                        int kern)
1032 {
1033         struct sock *sk = NULL;
1034         struct caifsock *cf_sk = NULL;
1035         static struct proto prot = {.name = "PF_CAIF",
1036                 .owner = THIS_MODULE,
1037                 .obj_size = sizeof(struct caifsock),
1038         };
1039
1040         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1041                 return -EPERM;
1042         /*
1043          * The sock->type specifies the socket type to use.
1044          * The CAIF socket is a packet stream in the sense
1045          * that it is packet based. CAIF trusts the reliability
1046          * of the link, no resending is implemented.
1047          */
1048         if (sock->type == SOCK_SEQPACKET)
1049                 sock->ops = &caif_seqpacket_ops;
1050         else if (sock->type == SOCK_STREAM)
1051                 sock->ops = &caif_stream_ops;
1052         else
1053                 return -ESOCKTNOSUPPORT;
1054
1055         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1056                 return -EPROTONOSUPPORT;
1057         /*
1058          * Set the socket state to unconnected.  The socket state
1059          * is really not used at all in the net/core or socket.c but the
1060          * initialization makes sure that sock->state is not uninitialized.
1061          */
1062         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1063         if (!sk)
1064                 return -ENOMEM;
1065
1066         cf_sk = container_of(sk, struct caifsock, sk);
1067
1068         /* Store the protocol */
1069         sk->sk_protocol = (unsigned char) protocol;
1070
1071         /* Initialize default priority for well-known cases */
1072         switch (protocol) {
1073         case CAIFPROTO_AT:
1074                 sk->sk_priority = TC_PRIO_CONTROL;
1075                 break;
1076         case CAIFPROTO_RFM:
1077                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1078                 break;
1079         default:
1080                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1081         }
1082
1083         /*
1084          * Lock in order to try to stop someone from opening the socket
1085          * too early.
1086          */
1087         lock_sock(&(cf_sk->sk));
1088
1089         /* Initialize the nozero default sock structure data. */
1090         sock_init_data(sock, sk);
1091         sk->sk_destruct = caif_sock_destructor;
1092
1093         mutex_init(&cf_sk->readlock); /* single task reading lock */
1094         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1095         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1096         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1097
1098         set_tx_flow_off(cf_sk);
1099         set_rx_flow_on(cf_sk);
1100
1101         /* Set default options on configuration */
1102         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1103         cf_sk->conn_req.protocol = protocol;
1104         release_sock(&cf_sk->sk);
1105         return 0;
1106 }
1107
1108
1109 static struct net_proto_family caif_family_ops = {
1110         .family = PF_CAIF,
1111         .create = caif_create,
1112         .owner = THIS_MODULE,
1113 };
1114
1115 static int __init caif_sktinit_module(void)
1116 {
1117         int err = sock_register(&caif_family_ops);
1118         if (!err)
1119                 return err;
1120         return 0;
1121 }
1122
1123 static void __exit caif_sktexit_module(void)
1124 {
1125         sock_unregister(PF_CAIF);
1126 }
1127 module_init(caif_sktinit_module);
1128 module_exit(caif_sktexit_module);