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