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         u32 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,
  60                         (void *) &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,
  66                         (void *) &cf_sk->flow_state);
  67 }
  68
  69 static void set_rx_flow_off(struct caifsock *cf_sk)
  70 {
  71          clear_bit(RX_FLOW_ON_BIT,
  72                  (void *) &cf_sk->flow_state);
  73 }
  74
  75 static void set_rx_flow_on(struct caifsock *cf_sk)
  76 {
  77          set_bit(RX_FLOW_ON_BIT,
  78                         (void *) &cf_sk->flow_state);
  79 }
  80
  81 static void set_tx_flow_off(struct caifsock *cf_sk)
  82 {
  83          clear_bit(TX_FLOW_ON_BIT,
  84                 (void *) &cf_sk->flow_state);
  85 }
  86
  87 static void set_tx_flow_on(struct caifsock *cf_sk)
  88 {
  89          set_bit(TX_FLOW_ON_BIT,
  90                 (void *) &cf_sk->flow_state);
  91 }
  92
  93 static void caif_read_lock(struct sock *sk)
  94 {
  95         struct caifsock *cf_sk;
  96         cf_sk = container_of(sk, struct caifsock, sk);
  97         mutex_lock(&cf_sk->readlock);
  98 }
  99
 100 static void caif_read_unlock(struct sock *sk)
 101 {
 102         struct caifsock *cf_sk;
 103         cf_sk = container_of(sk, struct caifsock, sk);
 104         mutex_unlock(&cf_sk->readlock);
 105 }
 106
 107 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 108 {
 109         /* A quarter of full buffer is used a low water mark */
 110         return cf_sk->sk.sk_rcvbuf / 4;
 111 }
 112
 113 static void caif_flow_ctrl(struct sock *sk, int mode)
 114 {
 115         struct caifsock *cf_sk;
 116         cf_sk = container_of(sk, struct caifsock, sk);
 117         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 118                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 119 }
 120
 121 /*
 122  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 123  * not dropped, but CAIF is sending flow off instead.
 124  */
 125 static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 126 {
 127         int err;
 128         unsigned long flags;
 129         struct sk_buff_head *list = &sk->sk_receive_queue;
 130         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 131         bool queued = false;
 132
 133         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 134                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 135                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 136                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
 137                                     sk_rcvbuf_lowwater(cf_sk));
 138                 set_rx_flow_off(cf_sk);
 139                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 140         }
 141
 142         err = sk_filter(sk, skb);
 143         if (err)
 144                 goto out;
 145
 146         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 147                 set_rx_flow_off(cf_sk);
 148                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 149                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 150         }
 151         skb->dev = NULL;
 152         skb_set_owner_r(skb, sk);
 153         spin_lock_irqsave(&list->lock, flags);
 154         queued = !sock_flag(sk, SOCK_DEAD);
 155         if (queued)
 156                 __skb_queue_tail(list, skb);
 157         spin_unlock_irqrestore(&list->lock, flags);
 158 out:
 159         if (queued)
 160                 sk->sk_data_ready(sk);
 161         else
 162                 kfree_skb(skb);
 163 }
 164
 165 /* Packet Receive Callback function called from CAIF Stack */
 166 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 167 {
 168         struct caifsock *cf_sk;
 169         struct sk_buff *skb;
 170
 171         cf_sk = container_of(layr, struct caifsock, layer);
 172         skb = cfpkt_tonative(pkt);
 173
 174         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 175                 kfree_skb(skb);
 176                 return 0;
 177         }
 178         caif_queue_rcv_skb(&cf_sk->sk, skb);
 179         return 0;
 180 }
 181
 182 static void cfsk_hold(struct cflayer *layr)
 183 {
 184         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 185         sock_hold(&cf_sk->sk);
 186 }
 187
 188 static void cfsk_put(struct cflayer *layr)
 189 {
 190         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 191         sock_put(&cf_sk->sk);
 192 }
 193
 194 /* Packet Control Callback function called from CAIF */
 195 static void caif_ctrl_cb(struct cflayer *layr,
 196                          enum caif_ctrlcmd flow,
 197                          int phyid)
 198 {
 199         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 200         switch (flow) {
 201         case CAIF_CTRLCMD_FLOW_ON_IND:
 202                 /* OK from modem to start sending again */
 203                 set_tx_flow_on(cf_sk);
 204                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 205                 break;
 206
 207         case CAIF_CTRLCMD_FLOW_OFF_IND:
 208                 /* Modem asks us to shut up */
 209                 set_tx_flow_off(cf_sk);
 210                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 211                 break;
 212
 213         case CAIF_CTRLCMD_INIT_RSP:
 214                 /* We're now connected */
 215                 caif_client_register_refcnt(&cf_sk->layer,
 216                                                 cfsk_hold, cfsk_put);
 217                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 218                 set_tx_flow_on(cf_sk);
 219                 cf_sk->sk.sk_shutdown = 0;
 220                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 221                 break;
 222
 223         case CAIF_CTRLCMD_DEINIT_RSP:
 224                 /* We're now disconnected */
 225                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 226                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 227                 break;
 228
 229         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 230                 /* Connect request failed */
 231                 cf_sk->sk.sk_err = ECONNREFUSED;
 232                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 233                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 234                 /*
 235                  * Socket "standards" seems to require POLLOUT to
 236                  * be set at connect failure.
 237                  */
 238                 set_tx_flow_on(cf_sk);
 239                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 240                 break;
 241
 242         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 243                 /* Modem has closed this connection, or device is down. */
 244                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 245                 cf_sk->sk.sk_err = ECONNRESET;
 246                 set_rx_flow_on(cf_sk);
 247                 sk_error_report(&cf_sk->sk);
 248                 break;
 249
 250         default:
 251                 pr_debug("Unexpected flow command %d\n", flow);
 252         }
 253 }
 254
 255 static void caif_check_flow_release(struct sock *sk)
 256 {
 257         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 258
 259         if (rx_flow_is_on(cf_sk))
 260                 return;
 261
 262         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 263                         set_rx_flow_on(cf_sk);
 264                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 265         }
 266 }
 267
 268 /*
 269  * Copied from unix_dgram_recvmsg, but removed credit checks,
 270  * changed locking, address handling and added MSG_TRUNC.
 271  */
 272 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
 273                                size_t len, int flags)
 274
 275 {
 276         struct sock *sk = sock->sk;
 277         struct sk_buff *skb;
 278         int ret;
 279         int copylen;
 280
 281         ret = -EOPNOTSUPP;
 282         if (flags & MSG_OOB)
 283                 goto read_error;
 284
 285         skb = skb_recv_datagram(sk, flags, &ret);
 286         if (!skb)
 287                 goto read_error;
 288         copylen = skb->len;
 289         if (len < copylen) {
 290                 m->msg_flags |= MSG_TRUNC;
 291                 copylen = len;
 292         }
 293
 294         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
 295         if (ret)
 296                 goto out_free;
 297
 298         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 299 out_free:
 300         skb_free_datagram(sk, skb);
 301         caif_check_flow_release(sk);
 302         return ret;
 303
 304 read_error:
 305         return ret;
 306 }
 307
 308
 309 /* Copied from unix_stream_wait_data, identical except for lock call. */
 310 static long caif_stream_data_wait(struct sock *sk, long timeo)
 311 {
 312         DEFINE_WAIT(wait);
 313         lock_sock(sk);
 314
 315         for (;;) {
 316                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 317
 318                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 319                         sk->sk_err ||
 320                         sk->sk_state != CAIF_CONNECTED ||
 321                         sock_flag(sk, SOCK_DEAD) ||
 322                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 323                         signal_pending(current) ||
 324                         !timeo)
 325                         break;
 326
 327                 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 328                 release_sock(sk);
 329                 timeo = schedule_timeout(timeo);
 330                 lock_sock(sk);
 331
 332                 if (sock_flag(sk, SOCK_DEAD))
 333                         break;
 334
 335                 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 336         }
 337
 338         finish_wait(sk_sleep(sk), &wait);
 339         release_sock(sk);
 340         return timeo;
 341 }
 342
 343
 344 /*
 345  * Copied from unix_stream_recvmsg, but removed credit checks,
 346  * changed locking calls, changed address handling.
 347  */
 348 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 349                                size_t size, int flags)
 350 {
 351         struct sock *sk = sock->sk;
 352         int copied = 0;
 353         int target;
 354         int err = 0;
 355         long timeo;
 356
 357         err = -EOPNOTSUPP;
 358         if (flags&MSG_OOB)
 359                 goto out;
 360
 361         /*
 362          * Lock the socket to prevent queue disordering
 363          * while sleeps in memcpy_tomsg
 364          */
 365         err = -EAGAIN;
 366         if (sk->sk_state == CAIF_CONNECTING)
 367                 goto out;
 368
 369         caif_read_lock(sk);
 370         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 371         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 372
 373         do {
 374                 int chunk;
 375                 struct sk_buff *skb;
 376
 377                 lock_sock(sk);
 378                 if (sock_flag(sk, SOCK_DEAD)) {
 379                         err = -ECONNRESET;
 380                         goto unlock;
 381                 }
 382                 skb = skb_dequeue(&sk->sk_receive_queue);
 383                 caif_check_flow_release(sk);
 384
 385                 if (skb == NULL) {
 386                         if (copied >= target)
 387                                 goto unlock;
 388                         /*
 389                          *      POSIX 1003.1g mandates this order.
 390                          */
 391                         err = sock_error(sk);
 392                         if (err)
 393                                 goto unlock;
 394                         err = -ECONNRESET;
 395                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 396                                 goto unlock;
 397
 398                         err = -EPIPE;
 399                         if (sk->sk_state != CAIF_CONNECTED)
 400                                 goto unlock;
 401                         if (sock_flag(sk, SOCK_DEAD))
 402                                 goto unlock;
 403
 404                         release_sock(sk);
 405
 406                         err = -EAGAIN;
 407                         if (!timeo)
 408                                 break;
 409
 410                         caif_read_unlock(sk);
 411
 412                         timeo = caif_stream_data_wait(sk, timeo);
 413
 414                         if (signal_pending(current)) {
 415                                 err = sock_intr_errno(timeo);
 416                                 goto out;
 417                         }
 418                         caif_read_lock(sk);
 419                         continue;
 420 unlock:
 421                         release_sock(sk);
 422                         break;
 423                 }
 424                 release_sock(sk);
 425                 chunk = min_t(unsigned int, skb->len, size);
 426                 if (memcpy_to_msg(msg, skb->data, chunk)) {
 427                         skb_queue_head(&sk->sk_receive_queue, skb);
 428                         if (copied == 0)
 429                                 copied = -EFAULT;
 430                         break;
 431                 }
 432                 copied += chunk;
 433                 size -= chunk;
 434
 435                 /* Mark read part of skb as used */
 436                 if (!(flags & MSG_PEEK)) {
 437                         skb_pull(skb, chunk);
 438
 439                         /* put the skb back if we didn't use it up. */
 440                         if (skb->len) {
 441                                 skb_queue_head(&sk->sk_receive_queue, skb);
 442                                 break;
 443                         }
 444                         kfree_skb(skb);
 445
 446                 } else {
 447                         /*
 448                          * It is questionable, see note in unix_dgram_recvmsg.
 449                          */
 450                         /* put message back and return */
 451                         skb_queue_head(&sk->sk_receive_queue, skb);
 452                         break;
 453                 }
 454         } while (size);
 455         caif_read_unlock(sk);
 456
 457 out:
 458         return copied ? : err;
 459 }
 460
 461 /*
 462  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 463  * CAIF flow-on and sock_writable.
 464  */
 465 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 466                                   int wait_writeable, long timeo, int *err)
 467 {
 468         struct sock *sk = &cf_sk->sk;
 469         DEFINE_WAIT(wait);
 470         for (;;) {
 471                 *err = 0;
 472                 if (tx_flow_is_on(cf_sk) &&
 473                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 474                         break;
 475                 *err = -ETIMEDOUT;
 476                 if (!timeo)
 477                         break;
 478                 *err = -ERESTARTSYS;
 479                 if (signal_pending(current))
 480                         break;
 481                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 482                 *err = -ECONNRESET;
 483                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 484                         break;
 485                 *err = -sk->sk_err;
 486                 if (sk->sk_err)
 487                         break;
 488                 *err = -EPIPE;
 489                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 490                         break;
 491                 timeo = schedule_timeout(timeo);
 492         }
 493         finish_wait(sk_sleep(sk), &wait);
 494         return timeo;
 495 }
 496
 497 /*
 498  * Transmit a SKB. The device may temporarily request re-transmission
 499  * by returning EAGAIN.
 500  */
 501 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 502                         int noblock, long timeo)
 503 {
 504         struct cfpkt *pkt;
 505
 506         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 507         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 508         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 509
 510         if (cf_sk->layer.dn == NULL) {
 511                 kfree_skb(skb);
 512                 return -EINVAL;
 513         }
 514
 515         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 516 }
 517
 518 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 519 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
 520                                size_t len)
 521 {
 522         struct sock *sk = sock->sk;
 523         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 524         int buffer_size;
 525         int ret = 0;
 526         struct sk_buff *skb = NULL;
 527         int noblock;
 528         long timeo;
 529         caif_assert(cf_sk);
 530         ret = sock_error(sk);
 531         if (ret)
 532                 goto err;
 533
 534         ret = -EOPNOTSUPP;
 535         if (msg->msg_flags&MSG_OOB)
 536                 goto err;
 537
 538         ret = -EOPNOTSUPP;
 539         if (msg->msg_namelen)
 540                 goto err;
 541
 542         ret = -EINVAL;
 543         if (unlikely(msg->msg_iter.nr_segs == 0) ||
 544             unlikely(msg->msg_iter.iov->iov_base == NULL))
 545                 goto err;
 546         noblock = msg->msg_flags & MSG_DONTWAIT;
 547
 548         timeo = sock_sndtimeo(sk, noblock);
 549         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 550                                 1, timeo, &ret);
 551
 552         if (ret)
 553                 goto err;
 554         ret = -EPIPE;
 555         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 556                 sock_flag(sk, SOCK_DEAD) ||
 557                 (sk->sk_shutdown & RCV_SHUTDOWN))
 558                 goto err;
 559
 560         /* Error if trying to write more than maximum frame size. */
 561         ret = -EMSGSIZE;
 562         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 563                 goto err;
 564
 565         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 566
 567         ret = -ENOMEM;
 568         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 569
 570         if (!skb || skb_tailroom(skb) < buffer_size)
 571                 goto err;
 572
 573         skb_reserve(skb, cf_sk->headroom);
 574
 575         ret = memcpy_from_msg(skb_put(skb, len), msg, len);
 576
 577         if (ret)
 578                 goto err;
 579         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 580         if (ret < 0)
 581                 /* skb is already freed */
 582                 return ret;
 583
 584         return len;
 585 err:
 586         kfree_skb(skb);
 587         return ret;
 588 }
 589
 590 /*
 591  * Copied from unix_stream_sendmsg and adapted to CAIF:
 592  * Changed removed permission handling and added waiting for flow on
 593  * and other minor adaptations.
 594  */
 595 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 596                                size_t len)
 597 {
 598         struct sock *sk = sock->sk;
 599         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 600         int err, size;
 601         struct sk_buff *skb;
 602         int sent = 0;
 603         long timeo;
 604
 605         err = -EOPNOTSUPP;
 606         if (unlikely(msg->msg_flags&MSG_OOB))
 607                 goto out_err;
 608
 609         if (unlikely(msg->msg_namelen))
 610                 goto out_err;
 611
 612         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 613         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 614
 615         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 616                 goto pipe_err;
 617
 618         while (sent < len) {
 619
 620                 size = len-sent;
 621
 622                 if (size > cf_sk->maxframe)
 623                         size = cf_sk->maxframe;
 624
 625                 /* If size is more than half of sndbuf, chop up message */
 626                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 627                         size = (sk->sk_sndbuf >> 1) - 64;
 628
 629                 if (size > SKB_MAX_ALLOC)
 630                         size = SKB_MAX_ALLOC;
 631
 632                 skb = sock_alloc_send_skb(sk,
 633                                         size + cf_sk->headroom +
 634                                         cf_sk->tailroom,
 635                                         msg->msg_flags&MSG_DONTWAIT,
 636                                         &err);
 637                 if (skb == NULL)
 638                         goto out_err;
 639
 640                 skb_reserve(skb, cf_sk->headroom);
 641                 /*
 642                  *      If you pass two values to the sock_alloc_send_skb
 643                  *      it tries to grab the large buffer with GFP_NOFS
 644                  *      (which can fail easily), and if it fails grab the
 645                  *      fallback size buffer which is under a page and will
 646                  *      succeed. [Alan]
 647                  */
 648                 size = min_t(int, size, skb_tailroom(skb));
 649
 650                 err = memcpy_from_msg(skb_put(skb, size), msg, size);
 651                 if (err) {
 652                         kfree_skb(skb);
 653                         goto out_err;
 654                 }
 655                 err = transmit_skb(skb, cf_sk,
 656                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 657                 if (err < 0)
 658                         /* skb is already freed */
 659                         goto pipe_err;
 660
 661                 sent += size;
 662         }
 663
 664         return sent;
 665
 666 pipe_err:
 667         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 668                 send_sig(SIGPIPE, current, 0);
 669         err = -EPIPE;
 670 out_err:
 671         return sent ? : err;
 672 }
 673
 674 static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov,
 675                 unsigned int ol)
 676 {
 677         struct sock *sk = sock->sk;
 678         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 679         int linksel;
 680
 681         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 682                 return -ENOPROTOOPT;
 683
 684         switch (opt) {
 685         case CAIFSO_LINK_SELECT:
 686                 if (ol < sizeof(int))
 687                         return -EINVAL;
 688                 if (lvl != SOL_CAIF)
 689                         goto bad_sol;
 690                 if (copy_from_sockptr(&linksel, ov, sizeof(int)))
 691                         return -EINVAL;
 692                 lock_sock(&(cf_sk->sk));
 693                 cf_sk->conn_req.link_selector = linksel;
 694                 release_sock(&cf_sk->sk);
 695                 return 0;
 696
 697         case CAIFSO_REQ_PARAM:
 698                 if (lvl != SOL_CAIF)
 699                         goto bad_sol;
 700                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 701                         return -ENOPROTOOPT;
 702                 lock_sock(&(cf_sk->sk));
 703                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 704                     copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) {
 705                         release_sock(&cf_sk->sk);
 706                         return -EINVAL;
 707                 }
 708                 cf_sk->conn_req.param.size = ol;
 709                 release_sock(&cf_sk->sk);
 710                 return 0;
 711
 712         default:
 713                 return -ENOPROTOOPT;
 714         }
 715
 716         return 0;
 717 bad_sol:
 718         return -ENOPROTOOPT;
 719
 720 }
 721
 722 /*
 723  * caif_connect() - Connect a CAIF Socket
 724  * Copied and modified af_irda.c:irda_connect().
 725  *
 726  * Note : by consulting "errno", the user space caller may learn the cause
 727  * of the failure. Most of them are visible in the function, others may come
 728  * from subroutines called and are listed here :
 729  *  o -EAFNOSUPPORT: bad socket family or type.
 730  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 731  *  o -EINVAL: bad socket address, or CAIF link type
 732  *  o -ECONNREFUSED: remote end refused the connection.
 733  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 734  *  o -EISCONN: already connected.
 735  *  o -ETIMEDOUT: Connection timed out (send timeout)
 736  *  o -ENODEV: No link layer to send request
 737  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 738  *  o -ENOMEM: Out of memory
 739  *
 740  *  State Strategy:
 741  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 742  *      caif_ctrl_cb.
 743  *  o sock->state: holds the SS_* socket state and is updated by connect and
 744  *      disconnect.
 745  */
 746 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 747                         int addr_len, int flags)
 748 {
 749         struct sock *sk = sock->sk;
 750         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 751         long timeo;
 752         int err;
 753         int ifindex, headroom, tailroom;
 754         unsigned int mtu;
 755         struct net_device *dev;
 756
 757         lock_sock(sk);
 758
 759         err = -EINVAL;
 760         if (addr_len < offsetofend(struct sockaddr, sa_family))
 761                 goto out;
 762
 763         err = -EAFNOSUPPORT;
 764         if (uaddr->sa_family != AF_CAIF)
 765                 goto out;
 766
 767         switch (sock->state) {
 768         case SS_UNCONNECTED:
 769                 /* Normal case, a fresh connect */
 770                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 771                 break;
 772         case SS_CONNECTING:
 773                 switch (sk->sk_state) {
 774                 case CAIF_CONNECTED:
 775                         sock->state = SS_CONNECTED;
 776                         err = -EISCONN;
 777                         goto out;
 778                 case CAIF_DISCONNECTED:
 779                         /* Reconnect allowed */
 780                         break;
 781                 case CAIF_CONNECTING:
 782                         err = -EALREADY;
 783                         if (flags & O_NONBLOCK)
 784                                 goto out;
 785                         goto wait_connect;
 786                 }
 787                 break;
 788         case SS_CONNECTED:
 789                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 790                                 sk->sk_state == CAIF_DISCONNECTED);
 791                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 792                         /* Allow re-connect after SHUTDOWN_IND */
 793                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 794                         caif_free_client(&cf_sk->layer);
 795                         break;
 796                 }
 797                 /* No reconnect on a seqpacket socket */
 798                 err = -EISCONN;
 799                 goto out;
 800         case SS_DISCONNECTING:
 801         case SS_FREE:
 802                 caif_assert(1); /*Should never happen */
 803                 break;
 804         }
 805         sk->sk_state = CAIF_DISCONNECTED;
 806         sock->state = SS_UNCONNECTED;
 807         sk_stream_kill_queues(&cf_sk->sk);
 808
 809         err = -EINVAL;
 810         if (addr_len != sizeof(struct sockaddr_caif))
 811                 goto out;
 812
 813         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 814                 sizeof(struct sockaddr_caif));
 815
 816         /* Move to connecting socket, start sending Connect Requests */
 817         sock->state = SS_CONNECTING;
 818         sk->sk_state = CAIF_CONNECTING;
 819
 820         /* Check priority value comming from socket */
 821         /* if priority value is out of range it will be ajusted */
 822         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 823                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 824         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 825                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 826         else
 827                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 828
 829         /*ifindex = id of the interface.*/
 830         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 831
 832         cf_sk->layer.receive = caif_sktrecv_cb;
 833
 834         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 835                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 836
 837         if (err < 0) {
 838                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 839                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 840                 goto out;
 841         }
 842
 843         err = -ENODEV;
 844         rcu_read_lock();
 845         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 846         if (!dev) {
 847                 rcu_read_unlock();
 848                 goto out;
 849         }
 850         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 851         mtu = dev->mtu;
 852         rcu_read_unlock();
 853
 854         cf_sk->tailroom = tailroom;
 855         cf_sk->maxframe = mtu - (headroom + tailroom);
 856         if (cf_sk->maxframe < 1) {
 857                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 858                 err = -ENODEV;
 859                 goto out;
 860         }
 861
 862         err = -EINPROGRESS;
 863 wait_connect:
 864
 865         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 866                 goto out;
 867
 868         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 869
 870         release_sock(sk);
 871         err = -ERESTARTSYS;
 872         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 873                         sk->sk_state != CAIF_CONNECTING,
 874                         timeo);
 875         lock_sock(sk);
 876         if (timeo < 0)
 877                 goto out; /* -ERESTARTSYS */
 878
 879         err = -ETIMEDOUT;
 880         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 881                 goto out;
 882         if (sk->sk_state != CAIF_CONNECTED) {
 883                 sock->state = SS_UNCONNECTED;
 884                 err = sock_error(sk);
 885                 if (!err)
 886                         err = -ECONNREFUSED;
 887                 goto out;
 888         }
 889         sock->state = SS_CONNECTED;
 890         err = 0;
 891 out:
 892         release_sock(sk);
 893         return err;
 894 }
 895
 896 /*
 897  * caif_release() - Disconnect a CAIF Socket
 898  * Copied and modified af_irda.c:irda_release().
 899  */
 900 static int caif_release(struct socket *sock)
 901 {
 902         struct sock *sk = sock->sk;
 903         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 904
 905         if (!sk)
 906                 return 0;
 907
 908         set_tx_flow_off(cf_sk);
 909
 910         /*
 911          * Ensure that packets are not queued after this point in time.
 912          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 913          * this ensures no packets when sock is dead.
 914          */
 915         spin_lock_bh(&sk->sk_receive_queue.lock);
 916         sock_set_flag(sk, SOCK_DEAD);
 917         spin_unlock_bh(&sk->sk_receive_queue.lock);
 918         sock->sk = NULL;
 919
 920         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 921         debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 922
 923         lock_sock(&(cf_sk->sk));
 924         sk->sk_state = CAIF_DISCONNECTED;
 925         sk->sk_shutdown = SHUTDOWN_MASK;
 926
 927         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 928         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 929         wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
 930
 931         sock_orphan(sk);
 932         sk_stream_kill_queues(&cf_sk->sk);
 933         release_sock(sk);
 934         sock_put(sk);
 935         return 0;
 936 }
 937
 938 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 939 static __poll_t caif_poll(struct file *file,
 940                               struct socket *sock, poll_table *wait)
 941 {
 942         struct sock *sk = sock->sk;
 943         __poll_t mask;
 944         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 945
 946         sock_poll_wait(file, sock, wait);
 947         mask = 0;
 948
 949         /* exceptional events? */
 950         if (sk->sk_err)
 951                 mask |= EPOLLERR;
 952         if (sk->sk_shutdown == SHUTDOWN_MASK)
 953                 mask |= EPOLLHUP;
 954         if (sk->sk_shutdown & RCV_SHUTDOWN)
 955                 mask |= EPOLLRDHUP;
 956
 957         /* readable? */
 958         if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
 959                 (sk->sk_shutdown & RCV_SHUTDOWN))
 960                 mask |= EPOLLIN | EPOLLRDNORM;
 961
 962         /*
 963          * we set writable also when the other side has shut down the
 964          * connection. This prevents stuck sockets.
 965          */
 966         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 967                 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
 968
 969         return mask;
 970 }
 971
 972 static const struct proto_ops caif_seqpacket_ops = {
 973         .family = PF_CAIF,
 974         .owner = THIS_MODULE,
 975         .release = caif_release,
 976         .bind = sock_no_bind,
 977         .connect = caif_connect,
 978         .socketpair = sock_no_socketpair,
 979         .accept = sock_no_accept,
 980         .getname = sock_no_getname,
 981         .poll = caif_poll,
 982         .ioctl = sock_no_ioctl,
 983         .listen = sock_no_listen,
 984         .shutdown = sock_no_shutdown,
 985         .setsockopt = setsockopt,
 986         .sendmsg = caif_seqpkt_sendmsg,
 987         .recvmsg = caif_seqpkt_recvmsg,
 988         .mmap = sock_no_mmap,
 989         .sendpage = sock_no_sendpage,
 990 };
 991
 992 static const struct proto_ops caif_stream_ops = {
 993         .family = PF_CAIF,
 994         .owner = THIS_MODULE,
 995         .release = caif_release,
 996         .bind = sock_no_bind,
 997         .connect = caif_connect,
 998         .socketpair = sock_no_socketpair,
 999         .accept = sock_no_accept,
1000         .getname = sock_no_getname,
1001         .poll = caif_poll,
1002         .ioctl = sock_no_ioctl,
1003         .listen = sock_no_listen,
1004         .shutdown = sock_no_shutdown,
1005         .setsockopt = setsockopt,
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);