net/caif/caif_socket.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland sjur.brandeland@stericsson.com
   4  * License terms: GNU General Public License (GPL) version 2
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9 #include <linux/fs.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/mutex.h>
  15 #include <linux/list.h>
  16 #include <linux/wait.h>
  17 #include <linux/poll.h>
  18 #include <linux/tcp.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/debugfs.h>
  21 #include <linux/caif/caif_socket.h>
  22 #include <linux/atomic.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 static struct dentry *debugfsdir;
  47
  48 #ifdef CONFIG_DEBUG_FS
  49 struct debug_fs_counter {
  50         atomic_t caif_nr_socks;
  51         atomic_t caif_sock_create;
  52         atomic_t num_connect_req;
  53         atomic_t num_connect_resp;
  54         atomic_t num_connect_fail_resp;
  55         atomic_t num_disconnect;
  56         atomic_t num_remote_shutdown_ind;
  57         atomic_t num_tx_flow_off_ind;
  58         atomic_t num_tx_flow_on_ind;
  59         atomic_t num_rx_flow_off;
  60         atomic_t num_rx_flow_on;
  61 };
  62 static struct debug_fs_counter cnt;
  63 #define dbfs_atomic_inc(v) atomic_inc_return(v)
  64 #define dbfs_atomic_dec(v) atomic_dec_return(v)
  65 #else
  66 #define dbfs_atomic_inc(v) 0
  67 #define dbfs_atomic_dec(v) 0
  68 #endif
  69
  70 struct caifsock {
  71         struct sock sk; /* must be first member */
  72         struct cflayer layer;
  73         char name[CAIF_LAYER_NAME_SZ]; /* Used for debugging */
  74         u32 flow_state;
  75         struct caif_connect_request conn_req;
  76         struct mutex readlock;
  77         struct dentry *debugfs_socket_dir;
  78         int headroom, tailroom, maxframe;
  79 };
  80
  81 static int rx_flow_is_on(struct caifsock *cf_sk)
  82 {
  83         return test_bit(RX_FLOW_ON_BIT,
  84                         (void *) &cf_sk->flow_state);
  85 }
  86
  87 static int tx_flow_is_on(struct caifsock *cf_sk)
  88 {
  89         return test_bit(TX_FLOW_ON_BIT,
  90                         (void *) &cf_sk->flow_state);
  91 }
  92
  93 static void set_rx_flow_off(struct caifsock *cf_sk)
  94 {
  95          clear_bit(RX_FLOW_ON_BIT,
  96                  (void *) &cf_sk->flow_state);
  97 }
  98
  99 static void set_rx_flow_on(struct caifsock *cf_sk)
 100 {
 101          set_bit(RX_FLOW_ON_BIT,
 102                         (void *) &cf_sk->flow_state);
 103 }
 104
 105 static void set_tx_flow_off(struct caifsock *cf_sk)
 106 {
 107          clear_bit(TX_FLOW_ON_BIT,
 108                 (void *) &cf_sk->flow_state);
 109 }
 110
 111 static void set_tx_flow_on(struct caifsock *cf_sk)
 112 {
 113          set_bit(TX_FLOW_ON_BIT,
 114                 (void *) &cf_sk->flow_state);
 115 }
 116
 117 static void caif_read_lock(struct sock *sk)
 118 {
 119         struct caifsock *cf_sk;
 120         cf_sk = container_of(sk, struct caifsock, sk);
 121         mutex_lock(&cf_sk->readlock);
 122 }
 123
 124 static void caif_read_unlock(struct sock *sk)
 125 {
 126         struct caifsock *cf_sk;
 127         cf_sk = container_of(sk, struct caifsock, sk);
 128         mutex_unlock(&cf_sk->readlock);
 129 }
 130
 131 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 132 {
 133         /* A quarter of full buffer is used a low water mark */
 134         return cf_sk->sk.sk_rcvbuf / 4;
 135 }
 136
 137 static void caif_flow_ctrl(struct sock *sk, int mode)
 138 {
 139         struct caifsock *cf_sk;
 140         cf_sk = container_of(sk, struct caifsock, sk);
 141         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 142                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 143 }
 144
 145 /*
 146  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 147  * not dropped, but CAIF is sending flow off instead.
 148  */
 149 static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 150 {
 151         int err;
 152         int skb_len;
 153         unsigned long flags;
 154         struct sk_buff_head *list = &sk->sk_receive_queue;
 155         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 156
 157         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 158                 (unsigned)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 159                 if (net_ratelimit())
 160                         pr_debug("sending flow OFF (queue len = %d %d)\n",
 161                                         atomic_read(&cf_sk->sk.sk_rmem_alloc),
 162                                         sk_rcvbuf_lowwater(cf_sk));
 163                 set_rx_flow_off(cf_sk);
 164                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
 165                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 166         }
 167
 168         err = sk_filter(sk, skb);
 169         if (err)
 170                 return err;
 171         if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
 172                 set_rx_flow_off(cf_sk);
 173                 if (net_ratelimit())
 174                         pr_debug("sending flow OFF due to rmem_schedule\n");
 175                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
 176                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 177         }
 178         skb->dev = NULL;
 179         skb_set_owner_r(skb, sk);
 180         /* Cache the SKB length before we tack it onto the receive
 181          * queue. Once it is added it no longer belongs to us and
 182          * may be freed by other threads of control pulling packets
 183          * from the queue.
 184          */
 185         skb_len = skb->len;
 186         spin_lock_irqsave(&list->lock, flags);
 187         if (!sock_flag(sk, SOCK_DEAD))
 188                 __skb_queue_tail(list, skb);
 189         spin_unlock_irqrestore(&list->lock, flags);
 190
 191         if (!sock_flag(sk, SOCK_DEAD))
 192                 sk->sk_data_ready(sk, skb_len);
 193         else
 194                 kfree_skb(skb);
 195         return 0;
 196 }
 197
 198 /* Packet Receive Callback function called from CAIF Stack */
 199 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 200 {
 201         struct caifsock *cf_sk;
 202         struct sk_buff *skb;
 203
 204         cf_sk = container_of(layr, struct caifsock, layer);
 205         skb = cfpkt_tonative(pkt);
 206
 207         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 208                 kfree_skb(skb);
 209                 return 0;
 210         }
 211         caif_queue_rcv_skb(&cf_sk->sk, skb);
 212         return 0;
 213 }
 214
 215 static void cfsk_hold(struct cflayer *layr)
 216 {
 217         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 218         sock_hold(&cf_sk->sk);
 219 }
 220
 221 static void cfsk_put(struct cflayer *layr)
 222 {
 223         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 224         sock_put(&cf_sk->sk);
 225 }
 226
 227 /* Packet Control Callback function called from CAIF */
 228 static void caif_ctrl_cb(struct cflayer *layr,
 229                                 enum caif_ctrlcmd flow,
 230                                 int phyid)
 231 {
 232         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 233         switch (flow) {
 234         case CAIF_CTRLCMD_FLOW_ON_IND:
 235                 /* OK from modem to start sending again */
 236                 dbfs_atomic_inc(&cnt.num_tx_flow_on_ind);
 237                 set_tx_flow_on(cf_sk);
 238                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 239                 break;
 240
 241         case CAIF_CTRLCMD_FLOW_OFF_IND:
 242                 /* Modem asks us to shut up */
 243                 dbfs_atomic_inc(&cnt.num_tx_flow_off_ind);
 244                 set_tx_flow_off(cf_sk);
 245                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 246                 break;
 247
 248         case CAIF_CTRLCMD_INIT_RSP:
 249                 /* We're now connected */
 250                 caif_client_register_refcnt(&cf_sk->layer,
 251                                                 cfsk_hold, cfsk_put);
 252                 dbfs_atomic_inc(&cnt.num_connect_resp);
 253                 cf_sk->sk.sk_state = CAIF_CONNECTED;
 254                 set_tx_flow_on(cf_sk);
 255                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 256                 break;
 257
 258         case CAIF_CTRLCMD_DEINIT_RSP:
 259                 /* We're now disconnected */
 260                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 261                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 262                 break;
 263
 264         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 265                 /* Connect request failed */
 266                 dbfs_atomic_inc(&cnt.num_connect_fail_resp);
 267                 cf_sk->sk.sk_err = ECONNREFUSED;
 268                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 269                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 270                 /*
 271                  * Socket "standards" seems to require POLLOUT to
 272                  * be set at connect failure.
 273                  */
 274                 set_tx_flow_on(cf_sk);
 275                 cf_sk->sk.sk_state_change(&cf_sk->sk);
 276                 break;
 277
 278         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 279                 /* Modem has closed this connection, or device is down. */
 280                 dbfs_atomic_inc(&cnt.num_remote_shutdown_ind);
 281                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 282                 cf_sk->sk.sk_err = ECONNRESET;
 283                 set_rx_flow_on(cf_sk);
 284                 cf_sk->sk.sk_error_report(&cf_sk->sk);
 285                 break;
 286
 287         default:
 288                 pr_debug("Unexpected flow command %d\n", flow);
 289         }
 290 }
 291
 292 static void caif_check_flow_release(struct sock *sk)
 293 {
 294         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 295
 296         if (rx_flow_is_on(cf_sk))
 297                 return;
 298
 299         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 300                         dbfs_atomic_inc(&cnt.num_rx_flow_on);
 301                         set_rx_flow_on(cf_sk);
 302                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 303         }
 304 }
 305
 306 /*
 307  * Copied from unix_dgram_recvmsg, but removed credit checks,
 308  * changed locking, address handling and added MSG_TRUNC.
 309  */
 310 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
 311                                 struct msghdr *m, size_t len, int flags)
 312
 313 {
 314         struct sock *sk = sock->sk;
 315         struct sk_buff *skb;
 316         int ret;
 317         int copylen;
 318
 319         ret = -EOPNOTSUPP;
 320         if (flags & MSG_OOB)
 321                 goto read_error;
 322
 323         skb = skb_recv_datagram(sk, flags, 0 , &ret);
 324         if (!skb)
 325                 goto read_error;
 326         copylen = skb->len;
 327         if (len < copylen) {
 328                 m->msg_flags |= MSG_TRUNC;
 329                 copylen = len;
 330         }
 331
 332         ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
 333         if (ret)
 334                 goto out_free;
 335
 336         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 337 out_free:
 338         skb_free_datagram(sk, skb);
 339         caif_check_flow_release(sk);
 340         return ret;
 341
 342 read_error:
 343         return ret;
 344 }
 345
 346
 347 /* Copied from unix_stream_wait_data, identical except for lock call. */
 348 static long caif_stream_data_wait(struct sock *sk, long timeo)
 349 {
 350         DEFINE_WAIT(wait);
 351         lock_sock(sk);
 352
 353         for (;;) {
 354                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 355
 356                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 357                         sk->sk_err ||
 358                         sk->sk_state != CAIF_CONNECTED ||
 359                         sock_flag(sk, SOCK_DEAD) ||
 360                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 361                         signal_pending(current) ||
 362                         !timeo)
 363                         break;
 364
 365                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 366                 release_sock(sk);
 367                 timeo = schedule_timeout(timeo);
 368                 lock_sock(sk);
 369                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 370         }
 371
 372         finish_wait(sk_sleep(sk), &wait);
 373         release_sock(sk);
 374         return timeo;
 375 }
 376
 377
 378 /*
 379  * Copied from unix_stream_recvmsg, but removed credit checks,
 380  * changed locking calls, changed address handling.
 381  */
 382 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 383                                 struct msghdr *msg, size_t size,
 384                                 int flags)
 385 {
 386         struct sock *sk = sock->sk;
 387         int copied = 0;
 388         int target;
 389         int err = 0;
 390         long timeo;
 391
 392         err = -EOPNOTSUPP;
 393         if (flags&MSG_OOB)
 394                 goto out;
 395
 396         /*
 397          * Lock the socket to prevent queue disordering
 398          * while sleeps in memcpy_tomsg
 399          */
 400         err = -EAGAIN;
 401         if (sk->sk_state == CAIF_CONNECTING)
 402                 goto out;
 403
 404         caif_read_lock(sk);
 405         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 406         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 407
 408         do {
 409                 int chunk;
 410                 struct sk_buff *skb;
 411
 412                 lock_sock(sk);
 413                 skb = skb_dequeue(&sk->sk_receive_queue);
 414                 caif_check_flow_release(sk);
 415
 416                 if (skb == NULL) {
 417                         if (copied >= target)
 418                                 goto unlock;
 419                         /*
 420                          *      POSIX 1003.1g mandates this order.
 421                          */
 422                         err = sock_error(sk);
 423                         if (err)
 424                                 goto unlock;
 425                         err = -ECONNRESET;
 426                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 427                                 goto unlock;
 428
 429                         err = -EPIPE;
 430                         if (sk->sk_state != CAIF_CONNECTED)
 431                                 goto unlock;
 432                         if (sock_flag(sk, SOCK_DEAD))
 433                                 goto unlock;
 434
 435                         release_sock(sk);
 436
 437                         err = -EAGAIN;
 438                         if (!timeo)
 439                                 break;
 440
 441                         caif_read_unlock(sk);
 442
 443                         timeo = caif_stream_data_wait(sk, timeo);
 444
 445                         if (signal_pending(current)) {
 446                                 err = sock_intr_errno(timeo);
 447                                 goto out;
 448                         }
 449                         caif_read_lock(sk);
 450                         continue;
 451 unlock:
 452                         release_sock(sk);
 453                         break;
 454                 }
 455                 release_sock(sk);
 456                 chunk = min_t(unsigned int, skb->len, size);
 457                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
 458                         skb_queue_head(&sk->sk_receive_queue, skb);
 459                         if (copied == 0)
 460                                 copied = -EFAULT;
 461                         break;
 462                 }
 463                 copied += chunk;
 464                 size -= chunk;
 465
 466                 /* Mark read part of skb as used */
 467                 if (!(flags & MSG_PEEK)) {
 468                         skb_pull(skb, chunk);
 469
 470                         /* put the skb back if we didn't use it up. */
 471                         if (skb->len) {
 472                                 skb_queue_head(&sk->sk_receive_queue, skb);
 473                                 break;
 474                         }
 475                         kfree_skb(skb);
 476
 477                 } else {
 478                         /*
 479                          * It is questionable, see note in unix_dgram_recvmsg.
 480                          */
 481                         /* put message back and return */
 482                         skb_queue_head(&sk->sk_receive_queue, skb);
 483                         break;
 484                 }
 485         } while (size);
 486         caif_read_unlock(sk);
 487
 488 out:
 489         return copied ? : err;
 490 }
 491
 492 /*
 493  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 494  * CAIF flow-on and sock_writable.
 495  */
 496 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 497                                 int wait_writeable, long timeo, int *err)
 498 {
 499         struct sock *sk = &cf_sk->sk;
 500         DEFINE_WAIT(wait);
 501         for (;;) {
 502                 *err = 0;
 503                 if (tx_flow_is_on(cf_sk) &&
 504                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 505                         break;
 506                 *err = -ETIMEDOUT;
 507                 if (!timeo)
 508                         break;
 509                 *err = -ERESTARTSYS;
 510                 if (signal_pending(current))
 511                         break;
 512                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 513                 *err = -ECONNRESET;
 514                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 515                         break;
 516                 *err = -sk->sk_err;
 517                 if (sk->sk_err)
 518                         break;
 519                 *err = -EPIPE;
 520                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 521                         break;
 522                 timeo = schedule_timeout(timeo);
 523         }
 524         finish_wait(sk_sleep(sk), &wait);
 525         return timeo;
 526 }
 527
 528 /*
 529  * Transmit a SKB. The device may temporarily request re-transmission
 530  * by returning EAGAIN.
 531  */
 532 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 533                         int noblock, long timeo)
 534 {
 535         struct cfpkt *pkt;
 536
 537         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 538         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 539
 540         if (cf_sk->layer.dn == NULL)
 541                 return -EINVAL;
 542
 543         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 544 }
 545
 546 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 547 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 548                         struct msghdr *msg, size_t len)
 549 {
 550         struct sock *sk = sock->sk;
 551         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 552         int buffer_size;
 553         int ret = 0;
 554         struct sk_buff *skb = NULL;
 555         int noblock;
 556         long timeo;
 557         caif_assert(cf_sk);
 558         ret = sock_error(sk);
 559         if (ret)
 560                 goto err;
 561
 562         ret = -EOPNOTSUPP;
 563         if (msg->msg_flags&MSG_OOB)
 564                 goto err;
 565
 566         ret = -EOPNOTSUPP;
 567         if (msg->msg_namelen)
 568                 goto err;
 569
 570         ret = -EINVAL;
 571         if (unlikely(msg->msg_iov->iov_base == NULL))
 572                 goto err;
 573         noblock = msg->msg_flags & MSG_DONTWAIT;
 574
 575         timeo = sock_sndtimeo(sk, noblock);
 576         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 577                                 1, timeo, &ret);
 578
 579         if (ret)
 580                 goto err;
 581         ret = -EPIPE;
 582         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 583                 sock_flag(sk, SOCK_DEAD) ||
 584                 (sk->sk_shutdown & RCV_SHUTDOWN))
 585                 goto err;
 586
 587         /* Error if trying to write more than maximum frame size. */
 588         ret = -EMSGSIZE;
 589         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 590                 goto err;
 591
 592         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 593
 594         ret = -ENOMEM;
 595         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 596
 597         if (!skb || skb_tailroom(skb) < buffer_size)
 598                 goto err;
 599
 600         skb_reserve(skb, cf_sk->headroom);
 601
 602         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 603
 604         if (ret)
 605                 goto err;
 606         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 607         if (ret < 0)
 608                 /* skb is already freed */
 609                 return ret;
 610
 611         return len;
 612 err:
 613         kfree_skb(skb);
 614         return ret;
 615 }
 616
 617 /*
 618  * Copied from unix_stream_sendmsg and adapted to CAIF:
 619  * Changed removed permission handling and added waiting for flow on
 620  * and other minor adaptations.
 621  */
 622 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 623                                 struct msghdr *msg, size_t len)
 624 {
 625         struct sock *sk = sock->sk;
 626         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 627         int err, size;
 628         struct sk_buff *skb;
 629         int sent = 0;
 630         long timeo;
 631
 632         err = -EOPNOTSUPP;
 633         if (unlikely(msg->msg_flags&MSG_OOB))
 634                 goto out_err;
 635
 636         if (unlikely(msg->msg_namelen))
 637                 goto out_err;
 638
 639         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 640         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 641
 642         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 643                 goto pipe_err;
 644
 645         while (sent < len) {
 646
 647                 size = len-sent;
 648
 649                 if (size > cf_sk->maxframe)
 650                         size = cf_sk->maxframe;
 651
 652                 /* If size is more than half of sndbuf, chop up message */
 653                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 654                         size = (sk->sk_sndbuf >> 1) - 64;
 655
 656                 if (size > SKB_MAX_ALLOC)
 657                         size = SKB_MAX_ALLOC;
 658
 659                 skb = sock_alloc_send_skb(sk,
 660                                         size + cf_sk->headroom +
 661                                         cf_sk->tailroom,
 662                                         msg->msg_flags&MSG_DONTWAIT,
 663                                         &err);
 664                 if (skb == NULL)
 665                         goto out_err;
 666
 667                 skb_reserve(skb, cf_sk->headroom);
 668                 /*
 669                  *      If you pass two values to the sock_alloc_send_skb
 670                  *      it tries to grab the large buffer with GFP_NOFS
 671                  *      (which can fail easily), and if it fails grab the
 672                  *      fallback size buffer which is under a page and will
 673                  *      succeed. [Alan]
 674                  */
 675                 size = min_t(int, size, skb_tailroom(skb));
 676
 677                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 678                 if (err) {
 679                         kfree_skb(skb);
 680                         goto out_err;
 681                 }
 682                 err = transmit_skb(skb, cf_sk,
 683                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 684                 if (err < 0) {
 685                         kfree_skb(skb);
 686                         goto pipe_err;
 687                 }
 688                 sent += size;
 689         }
 690
 691         return sent;
 692
 693 pipe_err:
 694         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 695                 send_sig(SIGPIPE, current, 0);
 696         err = -EPIPE;
 697 out_err:
 698         return sent ? : err;
 699 }
 700
 701 static int setsockopt(struct socket *sock,
 702                         int lvl, int opt, char __user *ov, unsigned int ol)
 703 {
 704         struct sock *sk = sock->sk;
 705         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 706         int linksel;
 707
 708         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 709                 return -ENOPROTOOPT;
 710
 711         switch (opt) {
 712         case CAIFSO_LINK_SELECT:
 713                 if (ol < sizeof(int))
 714                         return -EINVAL;
 715                 if (lvl != SOL_CAIF)
 716                         goto bad_sol;
 717                 if (copy_from_user(&linksel, ov, sizeof(int)))
 718                         return -EINVAL;
 719                 lock_sock(&(cf_sk->sk));
 720                 cf_sk->conn_req.link_selector = linksel;
 721                 release_sock(&cf_sk->sk);
 722                 return 0;
 723
 724         case CAIFSO_REQ_PARAM:
 725                 if (lvl != SOL_CAIF)
 726                         goto bad_sol;
 727                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 728                         return -ENOPROTOOPT;
 729                 lock_sock(&(cf_sk->sk));
 730                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 731                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 732                         release_sock(&cf_sk->sk);
 733                         return -EINVAL;
 734                 }
 735                 cf_sk->conn_req.param.size = ol;
 736                 release_sock(&cf_sk->sk);
 737                 return 0;
 738
 739         default:
 740                 return -ENOPROTOOPT;
 741         }
 742
 743         return 0;
 744 bad_sol:
 745         return -ENOPROTOOPT;
 746
 747 }
 748
 749 /*
 750  * caif_connect() - Connect a CAIF Socket
 751  * Copied and modified af_irda.c:irda_connect().
 752  *
 753  * Note : by consulting "errno", the user space caller may learn the cause
 754  * of the failure. Most of them are visible in the function, others may come
 755  * from subroutines called and are listed here :
 756  *  o -EAFNOSUPPORT: bad socket family or type.
 757  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 758  *  o -EINVAL: bad socket address, or CAIF link type
 759  *  o -ECONNREFUSED: remote end refused the connection.
 760  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 761  *  o -EISCONN: already connected.
 762  *  o -ETIMEDOUT: Connection timed out (send timeout)
 763  *  o -ENODEV: No link layer to send request
 764  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 765  *  o -ENOMEM: Out of memory
 766  *
 767  *  State Strategy:
 768  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 769  *      caif_ctrl_cb.
 770  *  o sock->state: holds the SS_* socket state and is updated by connect and
 771  *      disconnect.
 772  */
 773 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 774                         int addr_len, int flags)
 775 {
 776         struct sock *sk = sock->sk;
 777         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 778         long timeo;
 779         int err;
 780         int ifindex, headroom, tailroom;
 781         unsigned int mtu;
 782         struct net_device *dev;
 783
 784         lock_sock(sk);
 785
 786         err = -EAFNOSUPPORT;
 787         if (uaddr->sa_family != AF_CAIF)
 788                 goto out;
 789
 790         switch (sock->state) {
 791         case SS_UNCONNECTED:
 792                 /* Normal case, a fresh connect */
 793                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 794                 break;
 795         case SS_CONNECTING:
 796                 switch (sk->sk_state) {
 797                 case CAIF_CONNECTED:
 798                         sock->state = SS_CONNECTED;
 799                         err = -EISCONN;
 800                         goto out;
 801                 case CAIF_DISCONNECTED:
 802                         /* Reconnect allowed */
 803                         break;
 804                 case CAIF_CONNECTING:
 805                         err = -EALREADY;
 806                         if (flags & O_NONBLOCK)
 807                                 goto out;
 808                         goto wait_connect;
 809                 }
 810                 break;
 811         case SS_CONNECTED:
 812                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 813                                 sk->sk_state == CAIF_DISCONNECTED);
 814                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 815                         /* Allow re-connect after SHUTDOWN_IND */
 816                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 817                         caif_free_client(&cf_sk->layer);
 818                         break;
 819                 }
 820                 /* No reconnect on a seqpacket socket */
 821                 err = -EISCONN;
 822                 goto out;
 823         case SS_DISCONNECTING:
 824         case SS_FREE:
 825                 caif_assert(1); /*Should never happen */
 826                 break;
 827         }
 828         sk->sk_state = CAIF_DISCONNECTED;
 829         sock->state = SS_UNCONNECTED;
 830         sk_stream_kill_queues(&cf_sk->sk);
 831
 832         err = -EINVAL;
 833         if (addr_len != sizeof(struct sockaddr_caif))
 834                 goto out;
 835
 836         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 837                 sizeof(struct sockaddr_caif));
 838
 839         /* Move to connecting socket, start sending Connect Requests */
 840         sock->state = SS_CONNECTING;
 841         sk->sk_state = CAIF_CONNECTING;
 842
 843         /* Check priority value comming from socket */
 844         /* if priority value is out of range it will be ajusted */
 845         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 846                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 847         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 848                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 849         else
 850                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 851
 852         /*ifindex = id of the interface.*/
 853         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 854
 855         dbfs_atomic_inc(&cnt.num_connect_req);
 856         cf_sk->layer.receive = caif_sktrecv_cb;
 857
 858         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 859                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 860
 861         if (err < 0) {
 862                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 863                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 864                 goto out;
 865         }
 866
 867         err = -ENODEV;
 868         rcu_read_lock();
 869         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 870         if (!dev) {
 871                 rcu_read_unlock();
 872                 goto out;
 873         }
 874         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 875         mtu = dev->mtu;
 876         rcu_read_unlock();
 877
 878         cf_sk->tailroom = tailroom;
 879         cf_sk->maxframe = mtu - (headroom + tailroom);
 880         if (cf_sk->maxframe < 1) {
 881                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 882                 err = -ENODEV;
 883                 goto out;
 884         }
 885
 886         err = -EINPROGRESS;
 887 wait_connect:
 888
 889         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 890                 goto out;
 891
 892         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 893
 894         release_sock(sk);
 895         err = -ERESTARTSYS;
 896         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 897                         sk->sk_state != CAIF_CONNECTING,
 898                         timeo);
 899         lock_sock(sk);
 900         if (timeo < 0)
 901                 goto out; /* -ERESTARTSYS */
 902
 903         err = -ETIMEDOUT;
 904         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 905                 goto out;
 906         if (sk->sk_state != CAIF_CONNECTED) {
 907                 sock->state = SS_UNCONNECTED;
 908                 err = sock_error(sk);
 909                 if (!err)
 910                         err = -ECONNREFUSED;
 911                 goto out;
 912         }
 913         sock->state = SS_CONNECTED;
 914         err = 0;
 915 out:
 916         release_sock(sk);
 917         return err;
 918 }
 919
 920 /*
 921  * caif_release() - Disconnect a CAIF Socket
 922  * Copied and modified af_irda.c:irda_release().
 923  */
 924 static int caif_release(struct socket *sock)
 925 {
 926         struct sock *sk = sock->sk;
 927         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 928
 929         if (!sk)
 930                 return 0;
 931
 932         set_tx_flow_off(cf_sk);
 933
 934         /*
 935          * Ensure that packets are not queued after this point in time.
 936          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 937          * this ensures no packets when sock is dead.
 938          */
 939         spin_lock_bh(&sk->sk_receive_queue.lock);
 940         sock_set_flag(sk, SOCK_DEAD);
 941         spin_unlock_bh(&sk->sk_receive_queue.lock);
 942         sock->sk = NULL;
 943
 944         dbfs_atomic_inc(&cnt.num_disconnect);
 945
 946         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 947         if (cf_sk->debugfs_socket_dir != NULL)
 948                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 949
 950         lock_sock(&(cf_sk->sk));
 951         sk->sk_state = CAIF_DISCONNECTED;
 952         sk->sk_shutdown = SHUTDOWN_MASK;
 953
 954         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 955         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 956         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 957
 958         sock_orphan(sk);
 959         sk_stream_kill_queues(&cf_sk->sk);
 960         release_sock(sk);
 961         sock_put(sk);
 962         return 0;
 963 }
 964
 965 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 966 static unsigned int caif_poll(struct file *file,
 967                                 struct socket *sock, poll_table *wait)
 968 {
 969         struct sock *sk = sock->sk;
 970         unsigned int mask;
 971         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 972
 973         sock_poll_wait(file, sk_sleep(sk), wait);
 974         mask = 0;
 975
 976         /* exceptional events? */
 977         if (sk->sk_err)
 978                 mask |= POLLERR;
 979         if (sk->sk_shutdown == SHUTDOWN_MASK)
 980                 mask |= POLLHUP;
 981         if (sk->sk_shutdown & RCV_SHUTDOWN)
 982                 mask |= POLLRDHUP;
 983
 984         /* readable? */
 985         if (!skb_queue_empty(&sk->sk_receive_queue) ||
 986                 (sk->sk_shutdown & RCV_SHUTDOWN))
 987                 mask |= POLLIN | POLLRDNORM;
 988
 989         /*
 990          * we set writable also when the other side has shut down the
 991          * connection. This prevents stuck sockets.
 992          */
 993         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 994                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 995
 996         return mask;
 997 }
 998
 999 static const struct proto_ops caif_seqpacket_ops = {
1000         .family = PF_CAIF,
1001         .owner = THIS_MODULE,
1002         .release = caif_release,
1003         .bind = sock_no_bind,
1004         .connect = caif_connect,
1005         .socketpair = sock_no_socketpair,
1006         .accept = sock_no_accept,
1007         .getname = sock_no_getname,
1008         .poll = caif_poll,
1009         .ioctl = sock_no_ioctl,
1010         .listen = sock_no_listen,
1011         .shutdown = sock_no_shutdown,
1012         .setsockopt = setsockopt,
1013         .getsockopt = sock_no_getsockopt,
1014         .sendmsg = caif_seqpkt_sendmsg,
1015         .recvmsg = caif_seqpkt_recvmsg,
1016         .mmap = sock_no_mmap,
1017         .sendpage = sock_no_sendpage,
1018 };
1019
1020 static const struct proto_ops caif_stream_ops = {
1021         .family = PF_CAIF,
1022         .owner = THIS_MODULE,
1023         .release = caif_release,
1024         .bind = sock_no_bind,
1025         .connect = caif_connect,
1026         .socketpair = sock_no_socketpair,
1027         .accept = sock_no_accept,
1028         .getname = sock_no_getname,
1029         .poll = caif_poll,
1030         .ioctl = sock_no_ioctl,
1031         .listen = sock_no_listen,
1032         .shutdown = sock_no_shutdown,
1033         .setsockopt = setsockopt,
1034         .getsockopt = sock_no_getsockopt,
1035         .sendmsg = caif_stream_sendmsg,
1036         .recvmsg = caif_stream_recvmsg,
1037         .mmap = sock_no_mmap,
1038         .sendpage = sock_no_sendpage,
1039 };
1040
1041 /* This function is called when a socket is finally destroyed. */
1042 static void caif_sock_destructor(struct sock *sk)
1043 {
1044         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1045         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1046         caif_assert(sk_unhashed(sk));
1047         caif_assert(!sk->sk_socket);
1048         if (!sock_flag(sk, SOCK_DEAD)) {
1049                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1050                 return;
1051         }
1052         sk_stream_kill_queues(&cf_sk->sk);
1053         dbfs_atomic_dec(&cnt.caif_nr_socks);
1054         caif_free_client(&cf_sk->layer);
1055 }
1056
1057 static int caif_create(struct net *net, struct socket *sock, int protocol,
1058                         int kern)
1059 {
1060         int num;
1061         struct sock *sk = NULL;
1062         struct caifsock *cf_sk = NULL;
1063         static struct proto prot = {.name = "PF_CAIF",
1064                 .owner = THIS_MODULE,
1065                 .obj_size = sizeof(struct caifsock),
1066         };
1067
1068         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1069                 return -EPERM;
1070         /*
1071          * The sock->type specifies the socket type to use.
1072          * The CAIF socket is a packet stream in the sense
1073          * that it is packet based. CAIF trusts the reliability
1074          * of the link, no resending is implemented.
1075          */
1076         if (sock->type == SOCK_SEQPACKET)
1077                 sock->ops = &caif_seqpacket_ops;
1078         else if (sock->type == SOCK_STREAM)
1079                 sock->ops = &caif_stream_ops;
1080         else
1081                 return -ESOCKTNOSUPPORT;
1082
1083         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1084                 return -EPROTONOSUPPORT;
1085         /*
1086          * Set the socket state to unconnected.  The socket state
1087          * is really not used at all in the net/core or socket.c but the
1088          * initialization makes sure that sock->state is not uninitialized.
1089          */
1090         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1091         if (!sk)
1092                 return -ENOMEM;
1093
1094         cf_sk = container_of(sk, struct caifsock, sk);
1095
1096         /* Store the protocol */
1097         sk->sk_protocol = (unsigned char) protocol;
1098
1099         /*
1100          * Lock in order to try to stop someone from opening the socket
1101          * too early.
1102          */
1103         lock_sock(&(cf_sk->sk));
1104
1105         /* Initialize the nozero default sock structure data. */
1106         sock_init_data(sock, sk);
1107         sk->sk_destruct = caif_sock_destructor;
1108
1109         mutex_init(&cf_sk->readlock); /* single task reading lock */
1110         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1111         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1112         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1113
1114         set_tx_flow_off(cf_sk);
1115         set_rx_flow_on(cf_sk);
1116
1117         /* Set default options on configuration */
1118         cf_sk->sk.sk_priority = CAIF_PRIO_NORMAL;
1119         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1120         cf_sk->conn_req.protocol = protocol;
1121         /* Increase the number of sockets created. */
1122         dbfs_atomic_inc(&cnt.caif_nr_socks);
1123         num = dbfs_atomic_inc(&cnt.caif_sock_create);
1124 #ifdef CONFIG_DEBUG_FS
1125         if (!IS_ERR(debugfsdir)) {
1126
1127                 /* Fill in some information concerning the misc socket. */
1128                 snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d", num);
1129
1130                 cf_sk->debugfs_socket_dir =
1131                         debugfs_create_dir(cf_sk->name, debugfsdir);
1132
1133                 debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
1134                                 cf_sk->debugfs_socket_dir,
1135                                 (u32 *) &cf_sk->sk.sk_state);
1136                 debugfs_create_u32("flow_state", S_IRUSR | S_IWUSR,
1137                                 cf_sk->debugfs_socket_dir, &cf_sk->flow_state);
1138                 debugfs_create_u32("sk_rmem_alloc", S_IRUSR | S_IWUSR,
1139                                 cf_sk->debugfs_socket_dir,
1140                                 (u32 *) &cf_sk->sk.sk_rmem_alloc);
1141                 debugfs_create_u32("sk_wmem_alloc", S_IRUSR | S_IWUSR,
1142                                 cf_sk->debugfs_socket_dir,
1143                                 (u32 *) &cf_sk->sk.sk_wmem_alloc);
1144                 debugfs_create_u32("identity", S_IRUSR | S_IWUSR,
1145                                 cf_sk->debugfs_socket_dir,
1146                                 (u32 *) &cf_sk->layer.id);
1147         }
1148 #endif
1149         release_sock(&cf_sk->sk);
1150         return 0;
1151 }
1152
1153
1154 static struct net_proto_family caif_family_ops = {
1155         .family = PF_CAIF,
1156         .create = caif_create,
1157         .owner = THIS_MODULE,
1158 };
1159
1160 static int af_caif_init(void)
1161 {
1162         int err = sock_register(&caif_family_ops);
1163         if (!err)
1164                 return err;
1165         return 0;
1166 }
1167
1168 static int __init caif_sktinit_module(void)
1169 {
1170 #ifdef CONFIG_DEBUG_FS
1171         debugfsdir = debugfs_create_dir("caif_sk", NULL);
1172         if (!IS_ERR(debugfsdir)) {
1173                 debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
1174                                 debugfsdir,
1175                                 (u32 *) &cnt.caif_nr_socks);
1176                 debugfs_create_u32("num_create", S_IRUSR | S_IWUSR,
1177                                 debugfsdir,
1178                                 (u32 *) &cnt.caif_sock_create);
1179                 debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
1180                                 debugfsdir,
1181                                 (u32 *) &cnt.num_connect_req);
1182                 debugfs_create_u32("num_connect_resp", S_IRUSR | S_IWUSR,
1183                                 debugfsdir,
1184                                 (u32 *) &cnt.num_connect_resp);
1185                 debugfs_create_u32("num_connect_fail_resp", S_IRUSR | S_IWUSR,
1186                                 debugfsdir,
1187                                 (u32 *) &cnt.num_connect_fail_resp);
1188                 debugfs_create_u32("num_disconnect", S_IRUSR | S_IWUSR,
1189                                 debugfsdir,
1190                                 (u32 *) &cnt.num_disconnect);
1191                 debugfs_create_u32("num_remote_shutdown_ind",
1192                                 S_IRUSR | S_IWUSR, debugfsdir,
1193                                 (u32 *) &cnt.num_remote_shutdown_ind);
1194                 debugfs_create_u32("num_tx_flow_off_ind", S_IRUSR | S_IWUSR,
1195                                 debugfsdir,
1196                                 (u32 *) &cnt.num_tx_flow_off_ind);
1197                 debugfs_create_u32("num_tx_flow_on_ind", S_IRUSR | S_IWUSR,
1198                                 debugfsdir,
1199                                 (u32 *) &cnt.num_tx_flow_on_ind);
1200                 debugfs_create_u32("num_rx_flow_off", S_IRUSR | S_IWUSR,
1201                                 debugfsdir,
1202                                 (u32 *) &cnt.num_rx_flow_off);
1203                 debugfs_create_u32("num_rx_flow_on", S_IRUSR | S_IWUSR,
1204                                 debugfsdir,
1205                                 (u32 *) &cnt.num_rx_flow_on);
1206         }
1207 #endif
1208         return af_caif_init();
1209 }
1210
1211 static void __exit caif_sktexit_module(void)
1212 {
1213         sock_unregister(PF_CAIF);
1214         if (debugfsdir != NULL)
1215                 debugfs_remove_recursive(debugfsdir);
1216 }
1217 module_init(caif_sktinit_module);
1218 module_exit(caif_sktexit_module);