net/caif/caif_socket.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson AB 2010
   4  * Author:      Sjur Brendeland
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9 #include <linux/filter.h>
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/sched/signal.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/mutex.h>
  16 #include <linux/list.h>
  17 #include <linux/wait.h>
  18 #include <linux/poll.h>
  19 #include <linux/tcp.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/caif/caif_socket.h>
  23 #include <linux/pkt_sched.h>
  24 #include <net/sock.h>
  25 #include <net/tcp_states.h>
  26 #include <net/caif/caif_layer.h>
  27 #include <net/caif/caif_dev.h>
  28 #include <net/caif/cfpkt.h>
  29
  30 MODULE_LICENSE("GPL");
  31 MODULE_ALIAS_NETPROTO(AF_CAIF);
  32
  33 /*
  34  * CAIF state is re-using the TCP socket states.
  35  * caif_states stored in sk_state reflect the state as reported by
  36  * the CAIF stack, while sk_socket->state is the state of the socket.
  37  */
  38 enum caif_states {
  39         CAIF_CONNECTED          = TCP_ESTABLISHED,
  40         CAIF_CONNECTING = TCP_SYN_SENT,
  41         CAIF_DISCONNECTED       = TCP_CLOSE
  42 };
  43
  44 #define TX_FLOW_ON_BIT  1
  45 #define RX_FLOW_ON_BIT  2
  46
  47 struct caifsock {
  48         struct sock sk; /* must be first member */
  49         struct cflayer layer;
  50         unsigned long flow_state;
  51         struct caif_connect_request conn_req;
  52         struct mutex readlock;
  53         struct dentry *debugfs_socket_dir;
  54         int headroom, tailroom, maxframe;
  55 };
  56
  57 static int rx_flow_is_on(struct caifsock *cf_sk)
  58 {
  59         return test_bit(RX_FLOW_ON_BIT, &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, &cf_sk->flow_state);
  65 }
  66
  67 static void set_rx_flow_off(struct caifsock *cf_sk)
  68 {
  69         clear_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
  70 }
  71
  72 static void set_rx_flow_on(struct caifsock *cf_sk)
  73 {
  74         set_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
  75 }
  76
  77 static void set_tx_flow_off(struct caifsock *cf_sk)
  78 {
  79         clear_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
  80 }
  81
  82 static void set_tx_flow_on(struct caifsock *cf_sk)
  83 {
  84         set_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
  85 }
  86
  87 static void caif_read_lock(struct sock *sk)
  88 {
  89         struct caifsock *cf_sk;
  90         cf_sk = container_of(sk, struct caifsock, sk);
  91         mutex_lock(&cf_sk->readlock);
  92 }
  93
  94 static void caif_read_unlock(struct sock *sk)
  95 {
  96         struct caifsock *cf_sk;
  97         cf_sk = container_of(sk, struct caifsock, sk);
  98         mutex_unlock(&cf_sk->readlock);
  99 }
 100
 101 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 102 {
 103         /* A quarter of full buffer is used a low water mark */
 104         return cf_sk->sk.sk_rcvbuf / 4;
 105 }
 106
 107 static void caif_flow_ctrl(struct sock *sk, int mode)
 108 {
 109         struct caifsock *cf_sk;
 110         cf_sk = container_of(sk, struct caifsock, sk);
 111         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 112                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 113 }
 114
 115 /*
 116  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 117  * not dropped, but CAIF is sending flow off instead.
 118  */
 119 static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 120 {
 121         int err;
 122         unsigned long flags;
 123         struct sk_buff_head *list = &sk->sk_receive_queue;
 124         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 125         bool queued = false;
 126
 127         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 128                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 129                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 130                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
 131                                     sk_rcvbuf_lowwater(cf_sk));
 132                 set_rx_flow_off(cf_sk);
 133                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 134         }
 135
 136         err = sk_filter(sk, skb);
 137         if (err)
 138                 goto out;
 139
 140         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 141                 set_rx_flow_off(cf_sk);
 142                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 143                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 144         }
 145         skb->dev = NULL;
 146         skb_set_owner_r(skb, sk);
 147         spin_lock_irqsave(&list->lock, flags);
 148         queued = !sock_flag(sk, SOCK_DEAD);
 149         if (queued)
 150                 __skb_queue_tail(list, skb);
 151         spin_unlock_irqrestore(&list->lock, flags);
 152 out:
 153         if (queued)
 154                 sk->sk_data_ready(sk);
 155         else
 156                 kfree_skb(skb);
 157 }
 158
 159 /* Packet Receive Callback function called from CAIF Stack */
 160 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 161 {
 162         struct caifsock *cf_sk;
 163         struct sk_buff *skb;
 164
 165         cf_sk = container_of(layr, struct caifsock, layer);
 166         skb = cfpkt_tonative(pkt);
 167
 168         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 169                 kfree_skb(skb);
 170                 return 0;
 171         }
 172         caif_queue_rcv_skb(&cf_sk->sk, skb);
 173         return 0;
 174 }
 175
 176 static void cfsk_hold(struct cflayer *layr)
 177 {
 178         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 179         sock_hold(&cf_sk->sk);
 180 }
 181
 182 static void cfsk_put(struct cflayer *layr)
 183 {
 184         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 185         sock_put(&cf_sk->sk);
 186 }
 187
 188 /* Packet Control Callback function called from CAIF */
 189 static void caif_ctrl_cb(struct cflayer *layr,
 190                          enum caif_ctrlcmd flow,
 191                          int phyid)
 192 {
 193         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 194         switch (flow) {
 195         case CAIF_CTRLCMD_FLOW_ON_IND:
 196                 /* OK from modem to start sending again */
 197                 set_tx_flow_on(cf_sk);
 198                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 199                 break;
 200
 201         case CAIF_CTRLCMD_FLOW_OFF_IND:
 202                 /* Modem asks us to shut up */
 203                 set_tx_flow_off(cf_sk);
 204                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 205                 break;
 206
 207         case CAIF_CTRLCMD_INIT_RSP:
 208                 /* We're now connected */
 209                 caif_client_register_refcnt(&cf_sk->layer,
 210                                                 cfsk_hold, cfsk_put);
 211                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 212                 set_tx_flow_on(cf_sk);
 213                 cf_sk->sk.sk_shutdown = 0;
 214                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 215                 break;
 216
 217         case CAIF_CTRLCMD_DEINIT_RSP:
 218                 /* We're now disconnected */
 219                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 220                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 221                 break;
 222
 223         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 224                 /* Connect request failed */
 225                 cf_sk->sk.sk_err = ECONNREFUSED;
 226                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 227                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 228                 /*
 229                  * Socket "standards" seems to require POLLOUT to
 230                  * be set at connect failure.
 231                  */
 232                 set_tx_flow_on(cf_sk);
 233                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 234                 break;
 235
 236         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 237                 /* Modem has closed this connection, or device is down. */
 238                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 239                 cf_sk->sk.sk_err = ECONNRESET;
 240                 set_rx_flow_on(cf_sk);
 241                 sk_error_report(&cf_sk->sk);
 242                 break;
 243
 244         default:
 245                 pr_debug("Unexpected flow command %d\n", flow);
 246         }
 247 }
 248
 249 static void caif_check_flow_release(struct sock *sk)
 250 {
 251         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 252
 253         if (rx_flow_is_on(cf_sk))
 254                 return;
 255
 256         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 257                         set_rx_flow_on(cf_sk);
 258                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 259         }
 260 }
 261
 262 /*
 263  * Copied from unix_dgram_recvmsg, but removed credit checks,
 264  * changed locking, address handling and added MSG_TRUNC.
 265  */
 266 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
 267                                size_t len, int flags)
 268
 269 {
 270         struct sock *sk = sock->sk;
 271         struct sk_buff *skb;
 272         int ret;
 273         int copylen;
 274
 275         ret = -EOPNOTSUPP;
 276         if (flags & MSG_OOB)
 277                 goto read_error;
 278
 279         skb = skb_recv_datagram(sk, flags, &ret);
 280         if (!skb)
 281                 goto read_error;
 282         copylen = skb->len;
 283         if (len < copylen) {
 284                 m->msg_flags |= MSG_TRUNC;
 285                 copylen = len;
 286         }
 287
 288         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
 289         if (ret)
 290                 goto out_free;
 291
 292         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 293 out_free:
 294         skb_free_datagram(sk, skb);
 295         caif_check_flow_release(sk);
 296         return ret;
 297
 298 read_error:
 299         return ret;
 300 }
 301
 302
 303 /* Copied from unix_stream_wait_data, identical except for lock call. */
 304 static long caif_stream_data_wait(struct sock *sk, long timeo)
 305 {
 306         DEFINE_WAIT(wait);
 307         lock_sock(sk);
 308
 309         for (;;) {
 310                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 311
 312                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 313                         sk->sk_err ||
 314                         sk->sk_state != CAIF_CONNECTED ||
 315                         sock_flag(sk, SOCK_DEAD) ||
 316                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 317                         signal_pending(current) ||
 318                         !timeo)
 319                         break;
 320
 321                 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 322                 release_sock(sk);
 323                 timeo = schedule_timeout(timeo);
 324                 lock_sock(sk);
 325
 326                 if (sock_flag(sk, SOCK_DEAD))
 327                         break;
 328
 329                 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 330         }
 331
 332         finish_wait(sk_sleep(sk), &wait);
 333         release_sock(sk);
 334         return timeo;
 335 }
 336
 337
 338 /*
 339  * Copied from unix_stream_recvmsg, but removed credit checks,
 340  * changed locking calls, changed address handling.
 341  */
 342 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 343                                size_t size, int flags)
 344 {
 345         struct sock *sk = sock->sk;
 346         int copied = 0;
 347         int target;
 348         int err = 0;
 349         long timeo;
 350
 351         err = -EOPNOTSUPP;
 352         if (flags&MSG_OOB)
 353                 goto out;
 354
 355         /*
 356          * Lock the socket to prevent queue disordering
 357          * while sleeps in memcpy_tomsg
 358          */
 359         err = -EAGAIN;
 360         if (sk->sk_state == CAIF_CONNECTING)
 361                 goto out;
 362
 363         caif_read_lock(sk);
 364         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 365         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 366
 367         do {
 368                 int chunk;
 369                 struct sk_buff *skb;
 370
 371                 lock_sock(sk);
 372                 if (sock_flag(sk, SOCK_DEAD)) {
 373                         err = -ECONNRESET;
 374                         goto unlock;
 375                 }
 376                 skb = skb_dequeue(&sk->sk_receive_queue);
 377                 caif_check_flow_release(sk);
 378
 379                 if (skb == NULL) {
 380                         if (copied >= target)
 381                                 goto unlock;
 382                         /*
 383                          *      POSIX 1003.1g mandates this order.
 384                          */
 385                         err = sock_error(sk);
 386                         if (err)
 387                                 goto unlock;
 388                         err = -ECONNRESET;
 389                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 390                                 goto unlock;
 391
 392                         err = -EPIPE;
 393                         if (sk->sk_state != CAIF_CONNECTED)
 394                                 goto unlock;
 395                         if (sock_flag(sk, SOCK_DEAD))
 396                                 goto unlock;
 397
 398                         release_sock(sk);
 399
 400                         err = -EAGAIN;
 401                         if (!timeo)
 402                                 break;
 403
 404                         caif_read_unlock(sk);
 405
 406                         timeo = caif_stream_data_wait(sk, timeo);
 407
 408                         if (signal_pending(current)) {
 409                                 err = sock_intr_errno(timeo);
 410                                 goto out;
 411                         }
 412                         caif_read_lock(sk);
 413                         continue;
 414 unlock:
 415                         release_sock(sk);
 416                         break;
 417                 }
 418                 release_sock(sk);
 419                 chunk = min_t(unsigned int, skb->len, size);
 420                 if (memcpy_to_msg(msg, skb->data, chunk)) {
 421                         skb_queue_head(&sk->sk_receive_queue, skb);
 422                         if (copied == 0)
 423                                 copied = -EFAULT;
 424                         break;
 425                 }
 426                 copied += chunk;
 427                 size -= chunk;
 428
 429                 /* Mark read part of skb as used */
 430                 if (!(flags & MSG_PEEK)) {
 431                         skb_pull(skb, chunk);
 432
 433                         /* put the skb back if we didn't use it up. */
 434                         if (skb->len) {
 435                                 skb_queue_head(&sk->sk_receive_queue, skb);
 436                                 break;
 437                         }
 438                         kfree_skb(skb);
 439
 440                 } else {
 441                         /*
 442                          * It is questionable, see note in unix_dgram_recvmsg.
 443                          */
 444                         /* put message back and return */
 445                         skb_queue_head(&sk->sk_receive_queue, skb);
 446                         break;
 447                 }
 448         } while (size);
 449         caif_read_unlock(sk);
 450
 451 out:
 452         return copied ? : err;
 453 }
 454
 455 /*
 456  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 457  * CAIF flow-on and sock_writable.
 458  */
 459 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 460                                   int wait_writeable, long timeo, int *err)
 461 {
 462         struct sock *sk = &cf_sk->sk;
 463         DEFINE_WAIT(wait);
 464         for (;;) {
 465                 *err = 0;
 466                 if (tx_flow_is_on(cf_sk) &&
 467                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 468                         break;
 469                 *err = -ETIMEDOUT;
 470                 if (!timeo)
 471                         break;
 472                 *err = -ERESTARTSYS;
 473                 if (signal_pending(current))
 474                         break;
 475                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 476                 *err = -ECONNRESET;
 477                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 478                         break;
 479                 *err = -sk->sk_err;
 480                 if (sk->sk_err)
 481                         break;
 482                 *err = -EPIPE;
 483                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 484                         break;
 485                 timeo = schedule_timeout(timeo);
 486         }
 487         finish_wait(sk_sleep(sk), &wait);
 488         return timeo;
 489 }
 490
 491 /*
 492  * Transmit a SKB. The device may temporarily request re-transmission
 493  * by returning EAGAIN.
 494  */
 495 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 496                         int noblock, long timeo)
 497 {
 498         struct cfpkt *pkt;
 499
 500         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 501         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 502         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 503
 504         if (cf_sk->layer.dn == NULL) {
 505                 kfree_skb(skb);
 506                 return -EINVAL;
 507         }
 508
 509         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 510 }
 511
 512 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 513 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
 514                                size_t len)
 515 {
 516         struct sock *sk = sock->sk;
 517         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 518         int buffer_size;
 519         int ret = 0;
 520         struct sk_buff *skb = NULL;
 521         int noblock;
 522         long timeo;
 523         caif_assert(cf_sk);
 524         ret = sock_error(sk);
 525         if (ret)
 526                 goto err;
 527
 528         ret = -EOPNOTSUPP;
 529         if (msg->msg_flags&MSG_OOB)
 530                 goto err;
 531
 532         ret = -EOPNOTSUPP;
 533         if (msg->msg_namelen)
 534                 goto err;
 535
 536         ret = -EINVAL;
 537         if (unlikely(msg->msg_iter.nr_segs == 0) ||
 538             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 socket *sock, struct msghdr *msg,
 590                                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, int lvl, int opt, sockptr_t ov,
 669                 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_sockptr(&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_sockptr(&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 = -EINVAL;
 754         if (addr_len < offsetofend(struct sockaddr, sa_family))
 755                 goto out;
 756
 757         err = -EAFNOSUPPORT;
 758         if (uaddr->sa_family != AF_CAIF)
 759                 goto out;
 760
 761         switch (sock->state) {
 762         case SS_UNCONNECTED:
 763                 /* Normal case, a fresh connect */
 764                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 765                 break;
 766         case SS_CONNECTING:
 767                 switch (sk->sk_state) {
 768                 case CAIF_CONNECTED:
 769                         sock->state = SS_CONNECTED;
 770                         err = -EISCONN;
 771                         goto out;
 772                 case CAIF_DISCONNECTED:
 773                         /* Reconnect allowed */
 774                         break;
 775                 case CAIF_CONNECTING:
 776                         err = -EALREADY;
 777                         if (flags & O_NONBLOCK)
 778                                 goto out;
 779                         goto wait_connect;
 780                 }
 781                 break;
 782         case SS_CONNECTED:
 783                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 784                                 sk->sk_state == CAIF_DISCONNECTED);
 785                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 786                         /* Allow re-connect after SHUTDOWN_IND */
 787                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 788                         caif_free_client(&cf_sk->layer);
 789                         break;
 790                 }
 791                 /* No reconnect on a seqpacket socket */
 792                 err = -EISCONN;
 793                 goto out;
 794         case SS_DISCONNECTING:
 795         case SS_FREE:
 796                 caif_assert(1); /*Should never happen */
 797                 break;
 798         }
 799         sk->sk_state = CAIF_DISCONNECTED;
 800         sock->state = SS_UNCONNECTED;
 801         sk_stream_kill_queues(&cf_sk->sk);
 802
 803         err = -EINVAL;
 804         if (addr_len != sizeof(struct sockaddr_caif))
 805                 goto out;
 806
 807         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 808                 sizeof(struct sockaddr_caif));
 809
 810         /* Move to connecting socket, start sending Connect Requests */
 811         sock->state = SS_CONNECTING;
 812         sk->sk_state = CAIF_CONNECTING;
 813
 814         /* Check priority value comming from socket */
 815         /* if priority value is out of range it will be ajusted */
 816         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 817                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 818         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 819                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 820         else
 821                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 822
 823         /*ifindex = id of the interface.*/
 824         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 825
 826         cf_sk->layer.receive = caif_sktrecv_cb;
 827
 828         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 829                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 830
 831         if (err < 0) {
 832                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 833                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 834                 goto out;
 835         }
 836
 837         err = -ENODEV;
 838         rcu_read_lock();
 839         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 840         if (!dev) {
 841                 rcu_read_unlock();
 842                 goto out;
 843         }
 844         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 845         mtu = dev->mtu;
 846         rcu_read_unlock();
 847
 848         cf_sk->tailroom = tailroom;
 849         cf_sk->maxframe = mtu - (headroom + tailroom);
 850         if (cf_sk->maxframe < 1) {
 851                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 852                 err = -ENODEV;
 853                 goto out;
 854         }
 855
 856         err = -EINPROGRESS;
 857 wait_connect:
 858
 859         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 860                 goto out;
 861
 862         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 863
 864         release_sock(sk);
 865         err = -ERESTARTSYS;
 866         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 867                         sk->sk_state != CAIF_CONNECTING,
 868                         timeo);
 869         lock_sock(sk);
 870         if (timeo < 0)
 871                 goto out; /* -ERESTARTSYS */
 872
 873         err = -ETIMEDOUT;
 874         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 875                 goto out;
 876         if (sk->sk_state != CAIF_CONNECTED) {
 877                 sock->state = SS_UNCONNECTED;
 878                 err = sock_error(sk);
 879                 if (!err)
 880                         err = -ECONNREFUSED;
 881                 goto out;
 882         }
 883         sock->state = SS_CONNECTED;
 884         err = 0;
 885 out:
 886         release_sock(sk);
 887         return err;
 888 }
 889
 890 /*
 891  * caif_release() - Disconnect a CAIF Socket
 892  * Copied and modified af_irda.c:irda_release().
 893  */
 894 static int caif_release(struct socket *sock)
 895 {
 896         struct sock *sk = sock->sk;
 897         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 898
 899         if (!sk)
 900                 return 0;
 901
 902         set_tx_flow_off(cf_sk);
 903
 904         /*
 905          * Ensure that packets are not queued after this point in time.
 906          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 907          * this ensures no packets when sock is dead.
 908          */
 909         spin_lock_bh(&sk->sk_receive_queue.lock);
 910         sock_set_flag(sk, SOCK_DEAD);
 911         spin_unlock_bh(&sk->sk_receive_queue.lock);
 912         sock->sk = NULL;
 913
 914         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 915         debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 916
 917         lock_sock(&(cf_sk->sk));
 918         sk->sk_state = CAIF_DISCONNECTED;
 919         sk->sk_shutdown = SHUTDOWN_MASK;
 920
 921         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 922         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 923         wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
 924
 925         sock_orphan(sk);
 926         sk_stream_kill_queues(&cf_sk->sk);
 927         release_sock(sk);
 928         sock_put(sk);
 929         return 0;
 930 }
 931
 932 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 933 static __poll_t caif_poll(struct file *file,
 934                               struct socket *sock, poll_table *wait)
 935 {
 936         struct sock *sk = sock->sk;
 937         __poll_t mask;
 938         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 939
 940         sock_poll_wait(file, sock, wait);
 941         mask = 0;
 942
 943         /* exceptional events? */
 944         if (sk->sk_err)
 945                 mask |= EPOLLERR;
 946         if (sk->sk_shutdown == SHUTDOWN_MASK)
 947                 mask |= EPOLLHUP;
 948         if (sk->sk_shutdown & RCV_SHUTDOWN)
 949                 mask |= EPOLLRDHUP;
 950
 951         /* readable? */
 952         if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
 953                 (sk->sk_shutdown & RCV_SHUTDOWN))
 954                 mask |= EPOLLIN | EPOLLRDNORM;
 955
 956         /*
 957          * we set writable also when the other side has shut down the
 958          * connection. This prevents stuck sockets.
 959          */
 960         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 961                 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
 962
 963         return mask;
 964 }
 965
 966 static const struct proto_ops caif_seqpacket_ops = {
 967         .family = PF_CAIF,
 968         .owner = THIS_MODULE,
 969         .release = caif_release,
 970         .bind = sock_no_bind,
 971         .connect = caif_connect,
 972         .socketpair = sock_no_socketpair,
 973         .accept = sock_no_accept,
 974         .getname = sock_no_getname,
 975         .poll = caif_poll,
 976         .ioctl = sock_no_ioctl,
 977         .listen = sock_no_listen,
 978         .shutdown = sock_no_shutdown,
 979         .setsockopt = setsockopt,
 980         .sendmsg = caif_seqpkt_sendmsg,
 981         .recvmsg = caif_seqpkt_recvmsg,
 982         .mmap = sock_no_mmap,
 983         .sendpage = sock_no_sendpage,
 984 };
 985
 986 static const struct proto_ops caif_stream_ops = {
 987         .family = PF_CAIF,
 988         .owner = THIS_MODULE,
 989         .release = caif_release,
 990         .bind = sock_no_bind,
 991         .connect = caif_connect,
 992         .socketpair = sock_no_socketpair,
 993         .accept = sock_no_accept,
 994         .getname = sock_no_getname,
 995         .poll = caif_poll,
 996         .ioctl = sock_no_ioctl,
 997         .listen = sock_no_listen,
 998         .shutdown = sock_no_shutdown,
 999         .setsockopt = setsockopt,
1000         .sendmsg = caif_stream_sendmsg,
1001         .recvmsg = caif_stream_recvmsg,
1002         .mmap = sock_no_mmap,
1003         .sendpage = sock_no_sendpage,
1004 };
1005
1006 /* This function is called when a socket is finally destroyed. */
1007 static void caif_sock_destructor(struct sock *sk)
1008 {
1009         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1010         caif_assert(!refcount_read(&sk->sk_wmem_alloc));
1011         caif_assert(sk_unhashed(sk));
1012         caif_assert(!sk->sk_socket);
1013         if (!sock_flag(sk, SOCK_DEAD)) {
1014                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1015                 return;
1016         }
1017         sk_stream_kill_queues(&cf_sk->sk);
1018         caif_free_client(&cf_sk->layer);
1019 }
1020
1021 static int caif_create(struct net *net, struct socket *sock, int protocol,
1022                        int kern)
1023 {
1024         struct sock *sk = NULL;
1025         struct caifsock *cf_sk = NULL;
1026         static struct proto prot = {.name = "PF_CAIF",
1027                 .owner = THIS_MODULE,
1028                 .obj_size = sizeof(struct caifsock),
1029                 .useroffset = offsetof(struct caifsock, conn_req.param),
1030                 .usersize = sizeof_field(struct caifsock, conn_req.param)
1031         };
1032
1033         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1034                 return -EPERM;
1035         /*
1036          * The sock->type specifies the socket type to use.
1037          * The CAIF socket is a packet stream in the sense
1038          * that it is packet based. CAIF trusts the reliability
1039          * of the link, no resending is implemented.
1040          */
1041         if (sock->type == SOCK_SEQPACKET)
1042                 sock->ops = &caif_seqpacket_ops;
1043         else if (sock->type == SOCK_STREAM)
1044                 sock->ops = &caif_stream_ops;
1045         else
1046                 return -ESOCKTNOSUPPORT;
1047
1048         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1049                 return -EPROTONOSUPPORT;
1050         /*
1051          * Set the socket state to unconnected.  The socket state
1052          * is really not used at all in the net/core or socket.c but the
1053          * initialization makes sure that sock->state is not uninitialized.
1054          */
1055         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1056         if (!sk)
1057                 return -ENOMEM;
1058
1059         cf_sk = container_of(sk, struct caifsock, sk);
1060
1061         /* Store the protocol */
1062         sk->sk_protocol = (unsigned char) protocol;
1063
1064         /* Initialize default priority for well-known cases */
1065         switch (protocol) {
1066         case CAIFPROTO_AT:
1067                 sk->sk_priority = TC_PRIO_CONTROL;
1068                 break;
1069         case CAIFPROTO_RFM:
1070                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1071                 break;
1072         default:
1073                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1074         }
1075
1076         /*
1077          * Lock in order to try to stop someone from opening the socket
1078          * too early.
1079          */
1080         lock_sock(&(cf_sk->sk));
1081
1082         /* Initialize the nozero default sock structure data. */
1083         sock_init_data(sock, sk);
1084         sk->sk_destruct = caif_sock_destructor;
1085
1086         mutex_init(&cf_sk->readlock); /* single task reading lock */
1087         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1088         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1089         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1090
1091         set_tx_flow_off(cf_sk);
1092         set_rx_flow_on(cf_sk);
1093
1094         /* Set default options on configuration */
1095         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1096         cf_sk->conn_req.protocol = protocol;
1097         release_sock(&cf_sk->sk);
1098         return 0;
1099 }
1100
1101
1102 static const struct net_proto_family caif_family_ops = {
1103         .family = PF_CAIF,
1104         .create = caif_create,
1105         .owner = THIS_MODULE,
1106 };
1107
1108 static int __init caif_sktinit_module(void)
1109 {
1110         return sock_register(&caif_family_ops);
1111 }
1112
1113 static void __exit caif_sktexit_module(void)
1114 {
1115         sock_unregister(PF_CAIF);
1116 }
1117 module_init(caif_sktinit_module);
1118 module_exit(caif_sktexit_module);