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_DESCRIPTION("ST-Ericsson CAIF modem protocol socket support (AF_CAIF)");
  31 MODULE_LICENSE("GPL");
  32 MODULE_ALIAS_NETPROTO(AF_CAIF);
  33
  34 /*
  35  * CAIF state is re-using the TCP socket states.
  36  * caif_states stored in sk_state reflect the state as reported by
  37  * the CAIF stack, while sk_socket->state is the state of the socket.
  38  */
  39 enum caif_states {
  40         CAIF_CONNECTED          = TCP_ESTABLISHED,
  41         CAIF_CONNECTING = TCP_SYN_SENT,
  42         CAIF_DISCONNECTED       = TCP_CLOSE
  43 };
  44
  45 #define TX_FLOW_ON_BIT  1
  46 #define RX_FLOW_ON_BIT  2
  47
  48 struct caifsock {
  49         struct sock sk; /* must be first member */
  50         struct cflayer layer;
  51         unsigned long flow_state;
  52         struct caif_connect_request conn_req;
  53         struct mutex readlock;
  54         struct dentry *debugfs_socket_dir;
  55         int headroom, tailroom, maxframe;
  56 };
  57
  58 static int rx_flow_is_on(struct caifsock *cf_sk)
  59 {
  60         return test_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
  61 }
  62
  63 static int tx_flow_is_on(struct caifsock *cf_sk)
  64 {
  65         return test_bit(TX_FLOW_ON_BIT, &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, &cf_sk->flow_state);
  71 }
  72
  73 static void set_rx_flow_on(struct caifsock *cf_sk)
  74 {
  75         set_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
  76 }
  77
  78 static void set_tx_flow_off(struct caifsock *cf_sk)
  79 {
  80         clear_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
  81 }
  82
  83 static void set_tx_flow_on(struct caifsock *cf_sk)
  84 {
  85         set_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
  86 }
  87
  88 static void caif_read_lock(struct sock *sk)
  89 {
  90         struct caifsock *cf_sk;
  91         cf_sk = container_of(sk, struct caifsock, sk);
  92         mutex_lock(&cf_sk->readlock);
  93 }
  94
  95 static void caif_read_unlock(struct sock *sk)
  96 {
  97         struct caifsock *cf_sk;
  98         cf_sk = container_of(sk, struct caifsock, sk);
  99         mutex_unlock(&cf_sk->readlock);
 100 }
 101
 102 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 103 {
 104         /* A quarter of full buffer is used a low water mark */
 105         return cf_sk->sk.sk_rcvbuf / 4;
 106 }
 107
 108 static void caif_flow_ctrl(struct sock *sk, int mode)
 109 {
 110         struct caifsock *cf_sk;
 111         cf_sk = container_of(sk, struct caifsock, sk);
 112         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 113                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 114 }
 115
 116 /*
 117  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 118  * not dropped, but CAIF is sending flow off instead.
 119  */
 120 static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 121 {
 122         int err;
 123         unsigned long flags;
 124         struct sk_buff_head *list = &sk->sk_receive_queue;
 125         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 126         bool queued = false;
 127
 128         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 129                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 130                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 131                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
 132                                     sk_rcvbuf_lowwater(cf_sk));
 133                 set_rx_flow_off(cf_sk);
 134                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 135         }
 136
 137         err = sk_filter(sk, skb);
 138         if (err)
 139                 goto out;
 140
 141         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 142                 set_rx_flow_off(cf_sk);
 143                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 144                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 145         }
 146         skb->dev = NULL;
 147         skb_set_owner_r(skb, sk);
 148         spin_lock_irqsave(&list->lock, flags);
 149         queued = !sock_flag(sk, SOCK_DEAD);
 150         if (queued)
 151                 __skb_queue_tail(list, skb);
 152         spin_unlock_irqrestore(&list->lock, flags);
 153 out:
 154         if (queued)
 155                 sk->sk_data_ready(sk);
 156         else
 157                 kfree_skb(skb);
 158 }
 159
 160 /* Packet Receive Callback function called from CAIF Stack */
 161 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 162 {
 163         struct caifsock *cf_sk;
 164         struct sk_buff *skb;
 165
 166         cf_sk = container_of(layr, struct caifsock, layer);
 167         skb = cfpkt_tonative(pkt);
 168
 169         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 170                 kfree_skb(skb);
 171                 return 0;
 172         }
 173         caif_queue_rcv_skb(&cf_sk->sk, skb);
 174         return 0;
 175 }
 176
 177 static void cfsk_hold(struct cflayer *layr)
 178 {
 179         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 180         sock_hold(&cf_sk->sk);
 181 }
 182
 183 static void cfsk_put(struct cflayer *layr)
 184 {
 185         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 186         sock_put(&cf_sk->sk);
 187 }
 188
 189 /* Packet Control Callback function called from CAIF */
 190 static void caif_ctrl_cb(struct cflayer *layr,
 191                          enum caif_ctrlcmd flow,
 192                          int phyid)
 193 {
 194         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 195         switch (flow) {
 196         case CAIF_CTRLCMD_FLOW_ON_IND:
 197                 /* OK from modem to start sending again */
 198                 set_tx_flow_on(cf_sk);
 199                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 200                 break;
 201
 202         case CAIF_CTRLCMD_FLOW_OFF_IND:
 203                 /* Modem asks us to shut up */
 204                 set_tx_flow_off(cf_sk);
 205                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 206                 break;
 207
 208         case CAIF_CTRLCMD_INIT_RSP:
 209                 /* We're now connected */
 210                 caif_client_register_refcnt(&cf_sk->layer,
 211                                                 cfsk_hold, cfsk_put);
 212                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 213                 set_tx_flow_on(cf_sk);
 214                 cf_sk->sk.sk_shutdown = 0;
 215                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 216                 break;
 217
 218         case CAIF_CTRLCMD_DEINIT_RSP:
 219                 /* We're now disconnected */
 220                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 221                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 222                 break;
 223
 224         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 225                 /* Connect request failed */
 226                 cf_sk->sk.sk_err = ECONNREFUSED;
 227                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 228                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 229                 /*
 230                  * Socket "standards" seems to require POLLOUT to
 231                  * be set at connect failure.
 232                  */
 233                 set_tx_flow_on(cf_sk);
 234                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 235                 break;
 236
 237         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 238                 /* Modem has closed this connection, or device is down. */
 239                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 240                 cf_sk->sk.sk_err = ECONNRESET;
 241                 set_rx_flow_on(cf_sk);
 242                 sk_error_report(&cf_sk->sk);
 243                 break;
 244
 245         default:
 246                 pr_debug("Unexpected flow command %d\n", flow);
 247         }
 248 }
 249
 250 static void caif_check_flow_release(struct sock *sk)
 251 {
 252         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 253
 254         if (rx_flow_is_on(cf_sk))
 255                 return;
 256
 257         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 258                         set_rx_flow_on(cf_sk);
 259                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 260         }
 261 }
 262
 263 /*
 264  * Copied from unix_dgram_recvmsg, but removed credit checks,
 265  * changed locking, address handling and added MSG_TRUNC.
 266  */
 267 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
 268                                size_t len, int flags)
 269
 270 {
 271         struct sock *sk = sock->sk;
 272         struct sk_buff *skb;
 273         int ret;
 274         int copylen;
 275
 276         ret = -EOPNOTSUPP;
 277         if (flags & MSG_OOB)
 278                 goto read_error;
 279
 280         skb = skb_recv_datagram(sk, flags, &ret);
 281         if (!skb)
 282                 goto read_error;
 283         copylen = skb->len;
 284         if (len < copylen) {
 285                 m->msg_flags |= MSG_TRUNC;
 286                 copylen = len;
 287         }
 288
 289         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
 290         if (ret)
 291                 goto out_free;
 292
 293         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 294 out_free:
 295         skb_free_datagram(sk, skb);
 296         caif_check_flow_release(sk);
 297         return ret;
 298
 299 read_error:
 300         return ret;
 301 }
 302
 303
 304 /* Copied from unix_stream_wait_data, identical except for lock call. */
 305 static long caif_stream_data_wait(struct sock *sk, long timeo)
 306 {
 307         DEFINE_WAIT(wait);
 308         lock_sock(sk);
 309
 310         for (;;) {
 311                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 312
 313                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 314                         sk->sk_err ||
 315                         sk->sk_state != CAIF_CONNECTED ||
 316                         sock_flag(sk, SOCK_DEAD) ||
 317                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 318                         signal_pending(current) ||
 319                         !timeo)
 320                         break;
 321
 322                 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 323                 release_sock(sk);
 324                 timeo = schedule_timeout(timeo);
 325                 lock_sock(sk);
 326
 327                 if (sock_flag(sk, SOCK_DEAD))
 328                         break;
 329
 330                 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 331         }
 332
 333         finish_wait(sk_sleep(sk), &wait);
 334         release_sock(sk);
 335         return timeo;
 336 }
 337
 338
 339 /*
 340  * Copied from unix_stream_recvmsg, but removed credit checks,
 341  * changed locking calls, changed address handling.
 342  */
 343 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 344                                size_t size, int flags)
 345 {
 346         struct sock *sk = sock->sk;
 347         int copied = 0;
 348         int target;
 349         int err = 0;
 350         long timeo;
 351
 352         err = -EOPNOTSUPP;
 353         if (flags&MSG_OOB)
 354                 goto out;
 355
 356         /*
 357          * Lock the socket to prevent queue disordering
 358          * while sleeps in memcpy_tomsg
 359          */
 360         err = -EAGAIN;
 361         if (sk->sk_state == CAIF_CONNECTING)
 362                 goto out;
 363
 364         caif_read_lock(sk);
 365         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 366         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 367
 368         do {
 369                 int chunk;
 370                 struct sk_buff *skb;
 371
 372                 lock_sock(sk);
 373                 if (sock_flag(sk, SOCK_DEAD)) {
 374                         err = -ECONNRESET;
 375                         goto unlock;
 376                 }
 377                 skb = skb_dequeue(&sk->sk_receive_queue);
 378                 caif_check_flow_release(sk);
 379
 380                 if (skb == NULL) {
 381                         if (copied >= target)
 382                                 goto unlock;
 383                         /*
 384                          *      POSIX 1003.1g mandates this order.
 385                          */
 386                         err = sock_error(sk);
 387                         if (err)
 388                                 goto unlock;
 389                         err = -ECONNRESET;
 390                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 391                                 goto unlock;
 392
 393                         err = -EPIPE;
 394                         if (sk->sk_state != CAIF_CONNECTED)
 395                                 goto unlock;
 396                         if (sock_flag(sk, SOCK_DEAD))
 397                                 goto unlock;
 398
 399                         release_sock(sk);
 400
 401                         err = -EAGAIN;
 402                         if (!timeo)
 403                                 break;
 404
 405                         caif_read_unlock(sk);
 406
 407                         timeo = caif_stream_data_wait(sk, timeo);
 408
 409                         if (signal_pending(current)) {
 410                                 err = sock_intr_errno(timeo);
 411                                 goto out;
 412                         }
 413                         caif_read_lock(sk);
 414                         continue;
 415 unlock:
 416                         release_sock(sk);
 417                         break;
 418                 }
 419                 release_sock(sk);
 420                 chunk = min_t(unsigned int, skb->len, size);
 421                 if (memcpy_to_msg(msg, skb->data, chunk)) {
 422                         skb_queue_head(&sk->sk_receive_queue, skb);
 423                         if (copied == 0)
 424                                 copied = -EFAULT;
 425                         break;
 426                 }
 427                 copied += chunk;
 428                 size -= chunk;
 429
 430                 /* Mark read part of skb as used */
 431                 if (!(flags & MSG_PEEK)) {
 432                         skb_pull(skb, chunk);
 433
 434                         /* put the skb back if we didn't use it up. */
 435                         if (skb->len) {
 436                                 skb_queue_head(&sk->sk_receive_queue, skb);
 437                                 break;
 438                         }
 439                         kfree_skb(skb);
 440
 441                 } else {
 442                         /*
 443                          * It is questionable, see note in unix_dgram_recvmsg.
 444                          */
 445                         /* put message back and return */
 446                         skb_queue_head(&sk->sk_receive_queue, skb);
 447                         break;
 448                 }
 449         } while (size);
 450         caif_read_unlock(sk);
 451
 452 out:
 453         return copied ? : err;
 454 }
 455
 456 /*
 457  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 458  * CAIF flow-on and sock_writable.
 459  */
 460 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 461                                   int wait_writeable, long timeo, int *err)
 462 {
 463         struct sock *sk = &cf_sk->sk;
 464         DEFINE_WAIT(wait);
 465         for (;;) {
 466                 *err = 0;
 467                 if (tx_flow_is_on(cf_sk) &&
 468                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 469                         break;
 470                 *err = -ETIMEDOUT;
 471                 if (!timeo)
 472                         break;
 473                 *err = -ERESTARTSYS;
 474                 if (signal_pending(current))
 475                         break;
 476                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 477                 *err = -ECONNRESET;
 478                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 479                         break;
 480                 *err = -sk->sk_err;
 481                 if (sk->sk_err)
 482                         break;
 483                 *err = -EPIPE;
 484                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 485                         break;
 486                 timeo = schedule_timeout(timeo);
 487         }
 488         finish_wait(sk_sleep(sk), &wait);
 489         return timeo;
 490 }
 491
 492 /*
 493  * Transmit a SKB. The device may temporarily request re-transmission
 494  * by returning EAGAIN.
 495  */
 496 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 497                         int noblock, long timeo)
 498 {
 499         struct cfpkt *pkt;
 500
 501         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 502         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 503         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 504
 505         if (cf_sk->layer.dn == NULL) {
 506                 kfree_skb(skb);
 507                 return -EINVAL;
 508         }
 509
 510         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 511 }
 512
 513 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 514 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
 515                                size_t len)
 516 {
 517         struct sock *sk = sock->sk;
 518         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 519         int buffer_size;
 520         int ret = 0;
 521         struct sk_buff *skb = NULL;
 522         int noblock;
 523         long timeo;
 524         caif_assert(cf_sk);
 525         ret = sock_error(sk);
 526         if (ret)
 527                 goto err;
 528
 529         ret = -EOPNOTSUPP;
 530         if (msg->msg_flags&MSG_OOB)
 531                 goto err;
 532
 533         ret = -EOPNOTSUPP;
 534         if (msg->msg_namelen)
 535                 goto err;
 536
 537         noblock = msg->msg_flags & MSG_DONTWAIT;
 538
 539         timeo = sock_sndtimeo(sk, noblock);
 540         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 541                                 1, timeo, &ret);
 542
 543         if (ret)
 544                 goto err;
 545         ret = -EPIPE;
 546         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 547                 sock_flag(sk, SOCK_DEAD) ||
 548                 (sk->sk_shutdown & RCV_SHUTDOWN))
 549                 goto err;
 550
 551         /* Error if trying to write more than maximum frame size. */
 552         ret = -EMSGSIZE;
 553         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 554                 goto err;
 555
 556         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 557
 558         ret = -ENOMEM;
 559         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 560
 561         if (!skb || skb_tailroom(skb) < buffer_size)
 562                 goto err;
 563
 564         skb_reserve(skb, cf_sk->headroom);
 565
 566         ret = memcpy_from_msg(skb_put(skb, len), msg, len);
 567
 568         if (ret)
 569                 goto err;
 570         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 571         if (ret < 0)
 572                 /* skb is already freed */
 573                 return ret;
 574
 575         return len;
 576 err:
 577         kfree_skb(skb);
 578         return ret;
 579 }
 580
 581 /*
 582  * Copied from unix_stream_sendmsg and adapted to CAIF:
 583  * Changed removed permission handling and added waiting for flow on
 584  * and other minor adaptations.
 585  */
 586 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 587                                size_t len)
 588 {
 589         struct sock *sk = sock->sk;
 590         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 591         int err, size;
 592         struct sk_buff *skb;
 593         int sent = 0;
 594         long timeo;
 595
 596         err = -EOPNOTSUPP;
 597         if (unlikely(msg->msg_flags&MSG_OOB))
 598                 goto out_err;
 599
 600         if (unlikely(msg->msg_namelen))
 601                 goto out_err;
 602
 603         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 604         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 605
 606         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 607                 goto pipe_err;
 608
 609         while (sent < len) {
 610
 611                 size = len-sent;
 612
 613                 if (size > cf_sk->maxframe)
 614                         size = cf_sk->maxframe;
 615
 616                 /* If size is more than half of sndbuf, chop up message */
 617                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 618                         size = (sk->sk_sndbuf >> 1) - 64;
 619
 620                 if (size > SKB_MAX_ALLOC)
 621                         size = SKB_MAX_ALLOC;
 622
 623                 skb = sock_alloc_send_skb(sk,
 624                                         size + cf_sk->headroom +
 625                                         cf_sk->tailroom,
 626                                         msg->msg_flags&MSG_DONTWAIT,
 627                                         &err);
 628                 if (skb == NULL)
 629                         goto out_err;
 630
 631                 skb_reserve(skb, cf_sk->headroom);
 632                 /*
 633                  *      If you pass two values to the sock_alloc_send_skb
 634                  *      it tries to grab the large buffer with GFP_NOFS
 635                  *      (which can fail easily), and if it fails grab the
 636                  *      fallback size buffer which is under a page and will
 637                  *      succeed. [Alan]
 638                  */
 639                 size = min_t(int, size, skb_tailroom(skb));
 640
 641                 err = memcpy_from_msg(skb_put(skb, size), msg, size);
 642                 if (err) {
 643                         kfree_skb(skb);
 644                         goto out_err;
 645                 }
 646                 err = transmit_skb(skb, cf_sk,
 647                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 648                 if (err < 0)
 649                         /* skb is already freed */
 650                         goto pipe_err;
 651
 652                 sent += size;
 653         }
 654
 655         return sent;
 656
 657 pipe_err:
 658         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 659                 send_sig(SIGPIPE, current, 0);
 660         err = -EPIPE;
 661 out_err:
 662         return sent ? : err;
 663 }
 664
 665 static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov,
 666                 unsigned int ol)
 667 {
 668         struct sock *sk = sock->sk;
 669         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 670         int linksel;
 671
 672         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 673                 return -ENOPROTOOPT;
 674
 675         switch (opt) {
 676         case CAIFSO_LINK_SELECT:
 677                 if (ol < sizeof(int))
 678                         return -EINVAL;
 679                 if (lvl != SOL_CAIF)
 680                         goto bad_sol;
 681                 if (copy_from_sockptr(&linksel, ov, sizeof(int)))
 682                         return -EINVAL;
 683                 lock_sock(&(cf_sk->sk));
 684                 cf_sk->conn_req.link_selector = linksel;
 685                 release_sock(&cf_sk->sk);
 686                 return 0;
 687
 688         case CAIFSO_REQ_PARAM:
 689                 if (lvl != SOL_CAIF)
 690                         goto bad_sol;
 691                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 692                         return -ENOPROTOOPT;
 693                 lock_sock(&(cf_sk->sk));
 694                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 695                     copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) {
 696                         release_sock(&cf_sk->sk);
 697                         return -EINVAL;
 698                 }
 699                 cf_sk->conn_req.param.size = ol;
 700                 release_sock(&cf_sk->sk);
 701                 return 0;
 702
 703         default:
 704                 return -ENOPROTOOPT;
 705         }
 706
 707         return 0;
 708 bad_sol:
 709         return -ENOPROTOOPT;
 710
 711 }
 712
 713 /*
 714  * caif_connect() - Connect a CAIF Socket
 715  * Copied and modified af_irda.c:irda_connect().
 716  *
 717  * Note : by consulting "errno", the user space caller may learn the cause
 718  * of the failure. Most of them are visible in the function, others may come
 719  * from subroutines called and are listed here :
 720  *  o -EAFNOSUPPORT: bad socket family or type.
 721  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 722  *  o -EINVAL: bad socket address, or CAIF link type
 723  *  o -ECONNREFUSED: remote end refused the connection.
 724  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 725  *  o -EISCONN: already connected.
 726  *  o -ETIMEDOUT: Connection timed out (send timeout)
 727  *  o -ENODEV: No link layer to send request
 728  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 729  *  o -ENOMEM: Out of memory
 730  *
 731  *  State Strategy:
 732  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 733  *      caif_ctrl_cb.
 734  *  o sock->state: holds the SS_* socket state and is updated by connect and
 735  *      disconnect.
 736  */
 737 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 738                         int addr_len, int flags)
 739 {
 740         struct sock *sk = sock->sk;
 741         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 742         long timeo;
 743         int err;
 744         int ifindex, headroom, tailroom;
 745         unsigned int mtu;
 746         struct net_device *dev;
 747
 748         lock_sock(sk);
 749
 750         err = -EINVAL;
 751         if (addr_len < offsetofend(struct sockaddr, sa_family))
 752                 goto out;
 753
 754         err = -EAFNOSUPPORT;
 755         if (uaddr->sa_family != AF_CAIF)
 756                 goto out;
 757
 758         switch (sock->state) {
 759         case SS_UNCONNECTED:
 760                 /* Normal case, a fresh connect */
 761                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 762                 break;
 763         case SS_CONNECTING:
 764                 switch (sk->sk_state) {
 765                 case CAIF_CONNECTED:
 766                         sock->state = SS_CONNECTED;
 767                         err = -EISCONN;
 768                         goto out;
 769                 case CAIF_DISCONNECTED:
 770                         /* Reconnect allowed */
 771                         break;
 772                 case CAIF_CONNECTING:
 773                         err = -EALREADY;
 774                         if (flags & O_NONBLOCK)
 775                                 goto out;
 776                         goto wait_connect;
 777                 }
 778                 break;
 779         case SS_CONNECTED:
 780                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 781                                 sk->sk_state == CAIF_DISCONNECTED);
 782                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 783                         /* Allow re-connect after SHUTDOWN_IND */
 784                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 785                         caif_free_client(&cf_sk->layer);
 786                         break;
 787                 }
 788                 /* No reconnect on a seqpacket socket */
 789                 err = -EISCONN;
 790                 goto out;
 791         case SS_DISCONNECTING:
 792         case SS_FREE:
 793                 caif_assert(1); /*Should never happen */
 794                 break;
 795         }
 796         sk->sk_state = CAIF_DISCONNECTED;
 797         sock->state = SS_UNCONNECTED;
 798         sk_stream_kill_queues(&cf_sk->sk);
 799
 800         err = -EINVAL;
 801         if (addr_len != sizeof(struct sockaddr_caif))
 802                 goto out;
 803
 804         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 805                 sizeof(struct sockaddr_caif));
 806
 807         /* Move to connecting socket, start sending Connect Requests */
 808         sock->state = SS_CONNECTING;
 809         sk->sk_state = CAIF_CONNECTING;
 810
 811         /* Check priority value comming from socket */
 812         /* if priority value is out of range it will be ajusted */
 813         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 814                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 815         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 816                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 817         else
 818                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 819
 820         /*ifindex = id of the interface.*/
 821         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 822
 823         cf_sk->layer.receive = caif_sktrecv_cb;
 824
 825         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 826                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 827
 828         if (err < 0) {
 829                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 830                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 831                 goto out;
 832         }
 833
 834         err = -ENODEV;
 835         rcu_read_lock();
 836         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 837         if (!dev) {
 838                 rcu_read_unlock();
 839                 goto out;
 840         }
 841         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 842         mtu = dev->mtu;
 843         rcu_read_unlock();
 844
 845         cf_sk->tailroom = tailroom;
 846         cf_sk->maxframe = mtu - (headroom + tailroom);
 847         if (cf_sk->maxframe < 1) {
 848                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 849                 err = -ENODEV;
 850                 goto out;
 851         }
 852
 853         err = -EINPROGRESS;
 854 wait_connect:
 855
 856         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 857                 goto out;
 858
 859         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 860
 861         release_sock(sk);
 862         err = -ERESTARTSYS;
 863         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 864                         sk->sk_state != CAIF_CONNECTING,
 865                         timeo);
 866         lock_sock(sk);
 867         if (timeo < 0)
 868                 goto out; /* -ERESTARTSYS */
 869
 870         err = -ETIMEDOUT;
 871         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 872                 goto out;
 873         if (sk->sk_state != CAIF_CONNECTED) {
 874                 sock->state = SS_UNCONNECTED;
 875                 err = sock_error(sk);
 876                 if (!err)
 877                         err = -ECONNREFUSED;
 878                 goto out;
 879         }
 880         sock->state = SS_CONNECTED;
 881         err = 0;
 882 out:
 883         release_sock(sk);
 884         return err;
 885 }
 886
 887 /*
 888  * caif_release() - Disconnect a CAIF Socket
 889  * Copied and modified af_irda.c:irda_release().
 890  */
 891 static int caif_release(struct socket *sock)
 892 {
 893         struct sock *sk = sock->sk;
 894         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 895
 896         if (!sk)
 897                 return 0;
 898
 899         set_tx_flow_off(cf_sk);
 900
 901         /*
 902          * Ensure that packets are not queued after this point in time.
 903          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 904          * this ensures no packets when sock is dead.
 905          */
 906         spin_lock_bh(&sk->sk_receive_queue.lock);
 907         sock_set_flag(sk, SOCK_DEAD);
 908         spin_unlock_bh(&sk->sk_receive_queue.lock);
 909         sock->sk = NULL;
 910
 911         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 912         debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 913
 914         lock_sock(&(cf_sk->sk));
 915         sk->sk_state = CAIF_DISCONNECTED;
 916         sk->sk_shutdown = SHUTDOWN_MASK;
 917
 918         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 919         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 920         wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
 921
 922         sock_orphan(sk);
 923         sk_stream_kill_queues(&cf_sk->sk);
 924         release_sock(sk);
 925         sock_put(sk);
 926         return 0;
 927 }
 928
 929 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 930 static __poll_t caif_poll(struct file *file,
 931                               struct socket *sock, poll_table *wait)
 932 {
 933         struct sock *sk = sock->sk;
 934         __poll_t mask;
 935         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 936
 937         sock_poll_wait(file, sock, wait);
 938         mask = 0;
 939
 940         /* exceptional events? */
 941         if (sk->sk_err)
 942                 mask |= EPOLLERR;
 943         if (sk->sk_shutdown == SHUTDOWN_MASK)
 944                 mask |= EPOLLHUP;
 945         if (sk->sk_shutdown & RCV_SHUTDOWN)
 946                 mask |= EPOLLRDHUP;
 947
 948         /* readable? */
 949         if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
 950                 (sk->sk_shutdown & RCV_SHUTDOWN))
 951                 mask |= EPOLLIN | EPOLLRDNORM;
 952
 953         /*
 954          * we set writable also when the other side has shut down the
 955          * connection. This prevents stuck sockets.
 956          */
 957         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 958                 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
 959
 960         return mask;
 961 }
 962
 963 static const struct proto_ops caif_seqpacket_ops = {
 964         .family = PF_CAIF,
 965         .owner = THIS_MODULE,
 966         .release = caif_release,
 967         .bind = sock_no_bind,
 968         .connect = caif_connect,
 969         .socketpair = sock_no_socketpair,
 970         .accept = sock_no_accept,
 971         .getname = sock_no_getname,
 972         .poll = caif_poll,
 973         .ioctl = sock_no_ioctl,
 974         .listen = sock_no_listen,
 975         .shutdown = sock_no_shutdown,
 976         .setsockopt = setsockopt,
 977         .sendmsg = caif_seqpkt_sendmsg,
 978         .recvmsg = caif_seqpkt_recvmsg,
 979         .mmap = sock_no_mmap,
 980 };
 981
 982 static const struct proto_ops caif_stream_ops = {
 983         .family = PF_CAIF,
 984         .owner = THIS_MODULE,
 985         .release = caif_release,
 986         .bind = sock_no_bind,
 987         .connect = caif_connect,
 988         .socketpair = sock_no_socketpair,
 989         .accept = sock_no_accept,
 990         .getname = sock_no_getname,
 991         .poll = caif_poll,
 992         .ioctl = sock_no_ioctl,
 993         .listen = sock_no_listen,
 994         .shutdown = sock_no_shutdown,
 995         .setsockopt = setsockopt,
 996         .sendmsg = caif_stream_sendmsg,
 997         .recvmsg = caif_stream_recvmsg,
 998         .mmap = sock_no_mmap,
 999 };
1000
1001 /* This function is called when a socket is finally destroyed. */
1002 static void caif_sock_destructor(struct sock *sk)
1003 {
1004         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1005         caif_assert(!refcount_read(&sk->sk_wmem_alloc));
1006         caif_assert(sk_unhashed(sk));
1007         caif_assert(!sk->sk_socket);
1008         if (!sock_flag(sk, SOCK_DEAD)) {
1009                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1010                 return;
1011         }
1012         sk_stream_kill_queues(&cf_sk->sk);
1013         WARN_ON_ONCE(sk->sk_forward_alloc);
1014         caif_free_client(&cf_sk->layer);
1015 }
1016
1017 static int caif_create(struct net *net, struct socket *sock, int protocol,
1018                        int kern)
1019 {
1020         struct sock *sk = NULL;
1021         struct caifsock *cf_sk = NULL;
1022         static struct proto prot = {.name = "PF_CAIF",
1023                 .owner = THIS_MODULE,
1024                 .obj_size = sizeof(struct caifsock),
1025                 .useroffset = offsetof(struct caifsock, conn_req.param),
1026                 .usersize = sizeof_field(struct caifsock, conn_req.param)
1027         };
1028
1029         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1030                 return -EPERM;
1031         /*
1032          * The sock->type specifies the socket type to use.
1033          * The CAIF socket is a packet stream in the sense
1034          * that it is packet based. CAIF trusts the reliability
1035          * of the link, no resending is implemented.
1036          */
1037         if (sock->type == SOCK_SEQPACKET)
1038                 sock->ops = &caif_seqpacket_ops;
1039         else if (sock->type == SOCK_STREAM)
1040                 sock->ops = &caif_stream_ops;
1041         else
1042                 return -ESOCKTNOSUPPORT;
1043
1044         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1045                 return -EPROTONOSUPPORT;
1046         /*
1047          * Set the socket state to unconnected.  The socket state
1048          * is really not used at all in the net/core or socket.c but the
1049          * initialization makes sure that sock->state is not uninitialized.
1050          */
1051         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1052         if (!sk)
1053                 return -ENOMEM;
1054
1055         cf_sk = container_of(sk, struct caifsock, sk);
1056
1057         /* Store the protocol */
1058         sk->sk_protocol = (unsigned char) protocol;
1059
1060         /* Initialize default priority for well-known cases */
1061         switch (protocol) {
1062         case CAIFPROTO_AT:
1063                 sk->sk_priority = TC_PRIO_CONTROL;
1064                 break;
1065         case CAIFPROTO_RFM:
1066                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1067                 break;
1068         default:
1069                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1070         }
1071
1072         /*
1073          * Lock in order to try to stop someone from opening the socket
1074          * too early.
1075          */
1076         lock_sock(&(cf_sk->sk));
1077
1078         /* Initialize the nozero default sock structure data. */
1079         sock_init_data(sock, sk);
1080         sk->sk_destruct = caif_sock_destructor;
1081
1082         mutex_init(&cf_sk->readlock); /* single task reading lock */
1083         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1084         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1085         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1086
1087         set_tx_flow_off(cf_sk);
1088         set_rx_flow_on(cf_sk);
1089
1090         /* Set default options on configuration */
1091         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1092         cf_sk->conn_req.protocol = protocol;
1093         release_sock(&cf_sk->sk);
1094         return 0;
1095 }
1096
1097
1098 static const struct net_proto_family caif_family_ops = {
1099         .family = PF_CAIF,
1100         .create = caif_create,
1101         .owner = THIS_MODULE,
1102 };
1103
1104 static int __init caif_sktinit_module(void)
1105 {
1106         return sock_register(&caif_family_ops);
1107 }
1108
1109 static void __exit caif_sktexit_module(void)
1110 {
1111         sock_unregister(PF_CAIF);
1112 }
1113 module_init(caif_sktinit_module);
1114 module_exit(caif_sktexit_module);