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