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 (m->msg_flags&MSG_OOB)
 321                 goto read_error;
 322
 323         m->msg_namelen = 0;
 324
 325         skb = skb_recv_datagram(sk, flags, 0 , &ret);
 326         if (!skb)
 327                 goto read_error;
 328         copylen = skb->len;
 329         if (len < copylen) {
 330                 m->msg_flags |= MSG_TRUNC;
 331                 copylen = len;
 332         }
 333
 334         ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
 335         if (ret)
 336                 goto out_free;
 337
 338         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 339 out_free:
 340         skb_free_datagram(sk, skb);
 341         caif_check_flow_release(sk);
 342         return ret;
 343
 344 read_error:
 345         return ret;
 346 }
 347
 348
 349 /* Copied from unix_stream_wait_data, identical except for lock call. */
 350 static long caif_stream_data_wait(struct sock *sk, long timeo)
 351 {
 352         DEFINE_WAIT(wait);
 353         lock_sock(sk);
 354
 355         for (;;) {
 356                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 357
 358                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
 359                         sk->sk_err ||
 360                         sk->sk_state != CAIF_CONNECTED ||
 361                         sock_flag(sk, SOCK_DEAD) ||
 362                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
 363                         signal_pending(current) ||
 364                         !timeo)
 365                         break;
 366
 367                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 368                 release_sock(sk);
 369                 timeo = schedule_timeout(timeo);
 370                 lock_sock(sk);
 371                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 372         }
 373
 374         finish_wait(sk_sleep(sk), &wait);
 375         release_sock(sk);
 376         return timeo;
 377 }
 378
 379
 380 /*
 381  * Copied from unix_stream_recvmsg, but removed credit checks,
 382  * changed locking calls, changed address handling.
 383  */
 384 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 385                                 struct msghdr *msg, size_t size,
 386                                 int flags)
 387 {
 388         struct sock *sk = sock->sk;
 389         int copied = 0;
 390         int target;
 391         int err = 0;
 392         long timeo;
 393
 394         err = -EOPNOTSUPP;
 395         if (flags&MSG_OOB)
 396                 goto out;
 397
 398         msg->msg_namelen = 0;
 399
 400         /*
 401          * Lock the socket to prevent queue disordering
 402          * while sleeps in memcpy_tomsg
 403          */
 404         err = -EAGAIN;
 405         if (sk->sk_state == CAIF_CONNECTING)
 406                 goto out;
 407
 408         caif_read_lock(sk);
 409         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 410         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 411
 412         do {
 413                 int chunk;
 414                 struct sk_buff *skb;
 415
 416                 lock_sock(sk);
 417                 skb = skb_dequeue(&sk->sk_receive_queue);
 418                 caif_check_flow_release(sk);
 419
 420                 if (skb == NULL) {
 421                         if (copied >= target)
 422                                 goto unlock;
 423                         /*
 424                          *      POSIX 1003.1g mandates this order.
 425                          */
 426                         err = sock_error(sk);
 427                         if (err)
 428                                 goto unlock;
 429                         err = -ECONNRESET;
 430                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 431                                 goto unlock;
 432
 433                         err = -EPIPE;
 434                         if (sk->sk_state != CAIF_CONNECTED)
 435                                 goto unlock;
 436                         if (sock_flag(sk, SOCK_DEAD))
 437                                 goto unlock;
 438
 439                         release_sock(sk);
 440
 441                         err = -EAGAIN;
 442                         if (!timeo)
 443                                 break;
 444
 445                         caif_read_unlock(sk);
 446
 447                         timeo = caif_stream_data_wait(sk, timeo);
 448
 449                         if (signal_pending(current)) {
 450                                 err = sock_intr_errno(timeo);
 451                                 goto out;
 452                         }
 453                         caif_read_lock(sk);
 454                         continue;
 455 unlock:
 456                         release_sock(sk);
 457                         break;
 458                 }
 459                 release_sock(sk);
 460                 chunk = min_t(unsigned int, skb->len, size);
 461                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
 462                         skb_queue_head(&sk->sk_receive_queue, skb);
 463                         if (copied == 0)
 464                                 copied = -EFAULT;
 465                         break;
 466                 }
 467                 copied += chunk;
 468                 size -= chunk;
 469
 470                 /* Mark read part of skb as used */
 471                 if (!(flags & MSG_PEEK)) {
 472                         skb_pull(skb, chunk);
 473
 474                         /* put the skb back if we didn't use it up. */
 475                         if (skb->len) {
 476                                 skb_queue_head(&sk->sk_receive_queue, skb);
 477                                 break;
 478                         }
 479                         kfree_skb(skb);
 480
 481                 } else {
 482                         /*
 483                          * It is questionable, see note in unix_dgram_recvmsg.
 484                          */
 485                         /* put message back and return */
 486                         skb_queue_head(&sk->sk_receive_queue, skb);
 487                         break;
 488                 }
 489         } while (size);
 490         caif_read_unlock(sk);
 491
 492 out:
 493         return copied ? : err;
 494 }
 495
 496 /*
 497  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 498  * CAIF flow-on and sock_writable.
 499  */
 500 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 501                                 int wait_writeable, long timeo, int *err)
 502 {
 503         struct sock *sk = &cf_sk->sk;
 504         DEFINE_WAIT(wait);
 505         for (;;) {
 506                 *err = 0;
 507                 if (tx_flow_is_on(cf_sk) &&
 508                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
 509                         break;
 510                 *err = -ETIMEDOUT;
 511                 if (!timeo)
 512                         break;
 513                 *err = -ERESTARTSYS;
 514                 if (signal_pending(current))
 515                         break;
 516                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 517                 *err = -ECONNRESET;
 518                 if (sk->sk_shutdown & SHUTDOWN_MASK)
 519                         break;
 520                 *err = -sk->sk_err;
 521                 if (sk->sk_err)
 522                         break;
 523                 *err = -EPIPE;
 524                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 525                         break;
 526                 timeo = schedule_timeout(timeo);
 527         }
 528         finish_wait(sk_sleep(sk), &wait);
 529         return timeo;
 530 }
 531
 532 /*
 533  * Transmit a SKB. The device may temporarily request re-transmission
 534  * by returning EAGAIN.
 535  */
 536 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 537                         int noblock, long timeo)
 538 {
 539         struct cfpkt *pkt;
 540
 541         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 542         memset(skb->cb, 0, sizeof(struct caif_payload_info));
 543
 544         if (cf_sk->layer.dn == NULL)
 545                 return -EINVAL;
 546
 547         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 548 }
 549
 550 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 551 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 552                         struct msghdr *msg, size_t len)
 553 {
 554         struct sock *sk = sock->sk;
 555         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 556         int buffer_size;
 557         int ret = 0;
 558         struct sk_buff *skb = NULL;
 559         int noblock;
 560         long timeo;
 561         caif_assert(cf_sk);
 562         ret = sock_error(sk);
 563         if (ret)
 564                 goto err;
 565
 566         ret = -EOPNOTSUPP;
 567         if (msg->msg_flags&MSG_OOB)
 568                 goto err;
 569
 570         ret = -EOPNOTSUPP;
 571         if (msg->msg_namelen)
 572                 goto err;
 573
 574         ret = -EINVAL;
 575         if (unlikely(msg->msg_iov->iov_base == NULL))
 576                 goto err;
 577         noblock = msg->msg_flags & MSG_DONTWAIT;
 578
 579         timeo = sock_sndtimeo(sk, noblock);
 580         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 581                                 1, timeo, &ret);
 582
 583         if (ret)
 584                 goto err;
 585         ret = -EPIPE;
 586         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 587                 sock_flag(sk, SOCK_DEAD) ||
 588                 (sk->sk_shutdown & RCV_SHUTDOWN))
 589                 goto err;
 590
 591         /* Error if trying to write more than maximum frame size. */
 592         ret = -EMSGSIZE;
 593         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 594                 goto err;
 595
 596         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 597
 598         ret = -ENOMEM;
 599         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 600
 601         if (!skb || skb_tailroom(skb) < buffer_size)
 602                 goto err;
 603
 604         skb_reserve(skb, cf_sk->headroom);
 605
 606         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 607
 608         if (ret)
 609                 goto err;
 610         ret = transmit_skb(skb, cf_sk, noblock, timeo);
 611         if (ret < 0)
 612                 /* skb is already freed */
 613                 return ret;
 614
 615         return len;
 616 err:
 617         kfree_skb(skb);
 618         return ret;
 619 }
 620
 621 /*
 622  * Copied from unix_stream_sendmsg and adapted to CAIF:
 623  * Changed removed permission handling and added waiting for flow on
 624  * and other minor adaptations.
 625  */
 626 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 627                                 struct msghdr *msg, size_t len)
 628 {
 629         struct sock *sk = sock->sk;
 630         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 631         int err, size;
 632         struct sk_buff *skb;
 633         int sent = 0;
 634         long timeo;
 635
 636         err = -EOPNOTSUPP;
 637         if (unlikely(msg->msg_flags&MSG_OOB))
 638                 goto out_err;
 639
 640         if (unlikely(msg->msg_namelen))
 641                 goto out_err;
 642
 643         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 644         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 645
 646         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 647                 goto pipe_err;
 648
 649         while (sent < len) {
 650
 651                 size = len-sent;
 652
 653                 if (size > cf_sk->maxframe)
 654                         size = cf_sk->maxframe;
 655
 656                 /* If size is more than half of sndbuf, chop up message */
 657                 if (size > ((sk->sk_sndbuf >> 1) - 64))
 658                         size = (sk->sk_sndbuf >> 1) - 64;
 659
 660                 if (size > SKB_MAX_ALLOC)
 661                         size = SKB_MAX_ALLOC;
 662
 663                 skb = sock_alloc_send_skb(sk,
 664                                         size + cf_sk->headroom +
 665                                         cf_sk->tailroom,
 666                                         msg->msg_flags&MSG_DONTWAIT,
 667                                         &err);
 668                 if (skb == NULL)
 669                         goto out_err;
 670
 671                 skb_reserve(skb, cf_sk->headroom);
 672                 /*
 673                  *      If you pass two values to the sock_alloc_send_skb
 674                  *      it tries to grab the large buffer with GFP_NOFS
 675                  *      (which can fail easily), and if it fails grab the
 676                  *      fallback size buffer which is under a page and will
 677                  *      succeed. [Alan]
 678                  */
 679                 size = min_t(int, size, skb_tailroom(skb));
 680
 681                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 682                 if (err) {
 683                         kfree_skb(skb);
 684                         goto out_err;
 685                 }
 686                 err = transmit_skb(skb, cf_sk,
 687                                 msg->msg_flags&MSG_DONTWAIT, timeo);
 688                 if (err < 0) {
 689                         kfree_skb(skb);
 690                         goto pipe_err;
 691                 }
 692                 sent += size;
 693         }
 694
 695         return sent;
 696
 697 pipe_err:
 698         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 699                 send_sig(SIGPIPE, current, 0);
 700         err = -EPIPE;
 701 out_err:
 702         return sent ? : err;
 703 }
 704
 705 static int setsockopt(struct socket *sock,
 706                         int lvl, int opt, char __user *ov, unsigned int ol)
 707 {
 708         struct sock *sk = sock->sk;
 709         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 710         int linksel;
 711
 712         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 713                 return -ENOPROTOOPT;
 714
 715         switch (opt) {
 716         case CAIFSO_LINK_SELECT:
 717                 if (ol < sizeof(int))
 718                         return -EINVAL;
 719                 if (lvl != SOL_CAIF)
 720                         goto bad_sol;
 721                 if (copy_from_user(&linksel, ov, sizeof(int)))
 722                         return -EINVAL;
 723                 lock_sock(&(cf_sk->sk));
 724                 cf_sk->conn_req.link_selector = linksel;
 725                 release_sock(&cf_sk->sk);
 726                 return 0;
 727
 728         case CAIFSO_REQ_PARAM:
 729                 if (lvl != SOL_CAIF)
 730                         goto bad_sol;
 731                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 732                         return -ENOPROTOOPT;
 733                 lock_sock(&(cf_sk->sk));
 734                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
 735                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 736                         release_sock(&cf_sk->sk);
 737                         return -EINVAL;
 738                 }
 739                 cf_sk->conn_req.param.size = ol;
 740                 release_sock(&cf_sk->sk);
 741                 return 0;
 742
 743         default:
 744                 return -ENOPROTOOPT;
 745         }
 746
 747         return 0;
 748 bad_sol:
 749         return -ENOPROTOOPT;
 750
 751 }
 752
 753 /*
 754  * caif_connect() - Connect a CAIF Socket
 755  * Copied and modified af_irda.c:irda_connect().
 756  *
 757  * Note : by consulting "errno", the user space caller may learn the cause
 758  * of the failure. Most of them are visible in the function, others may come
 759  * from subroutines called and are listed here :
 760  *  o -EAFNOSUPPORT: bad socket family or type.
 761  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 762  *  o -EINVAL: bad socket address, or CAIF link type
 763  *  o -ECONNREFUSED: remote end refused the connection.
 764  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 765  *  o -EISCONN: already connected.
 766  *  o -ETIMEDOUT: Connection timed out (send timeout)
 767  *  o -ENODEV: No link layer to send request
 768  *  o -ECONNRESET: Received Shutdown indication or lost link layer
 769  *  o -ENOMEM: Out of memory
 770  *
 771  *  State Strategy:
 772  *  o sk_state: holds the CAIF_* protocol state, it's updated by
 773  *      caif_ctrl_cb.
 774  *  o sock->state: holds the SS_* socket state and is updated by connect and
 775  *      disconnect.
 776  */
 777 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 778                         int addr_len, int flags)
 779 {
 780         struct sock *sk = sock->sk;
 781         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 782         long timeo;
 783         int err;
 784         int ifindex, headroom, tailroom;
 785         unsigned int mtu;
 786         struct net_device *dev;
 787
 788         lock_sock(sk);
 789
 790         err = -EAFNOSUPPORT;
 791         if (uaddr->sa_family != AF_CAIF)
 792                 goto out;
 793
 794         switch (sock->state) {
 795         case SS_UNCONNECTED:
 796                 /* Normal case, a fresh connect */
 797                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 798                 break;
 799         case SS_CONNECTING:
 800                 switch (sk->sk_state) {
 801                 case CAIF_CONNECTED:
 802                         sock->state = SS_CONNECTED;
 803                         err = -EISCONN;
 804                         goto out;
 805                 case CAIF_DISCONNECTED:
 806                         /* Reconnect allowed */
 807                         break;
 808                 case CAIF_CONNECTING:
 809                         err = -EALREADY;
 810                         if (flags & O_NONBLOCK)
 811                                 goto out;
 812                         goto wait_connect;
 813                 }
 814                 break;
 815         case SS_CONNECTED:
 816                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
 817                                 sk->sk_state == CAIF_DISCONNECTED);
 818                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
 819                         /* Allow re-connect after SHUTDOWN_IND */
 820                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 821                         caif_free_client(&cf_sk->layer);
 822                         break;
 823                 }
 824                 /* No reconnect on a seqpacket socket */
 825                 err = -EISCONN;
 826                 goto out;
 827         case SS_DISCONNECTING:
 828         case SS_FREE:
 829                 caif_assert(1); /*Should never happen */
 830                 break;
 831         }
 832         sk->sk_state = CAIF_DISCONNECTED;
 833         sock->state = SS_UNCONNECTED;
 834         sk_stream_kill_queues(&cf_sk->sk);
 835
 836         err = -EINVAL;
 837         if (addr_len != sizeof(struct sockaddr_caif))
 838                 goto out;
 839
 840         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 841                 sizeof(struct sockaddr_caif));
 842
 843         /* Move to connecting socket, start sending Connect Requests */
 844         sock->state = SS_CONNECTING;
 845         sk->sk_state = CAIF_CONNECTING;
 846
 847         /* Check priority value comming from socket */
 848         /* if priority value is out of range it will be ajusted */
 849         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 850                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 851         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 852                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 853         else
 854                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 855
 856         /*ifindex = id of the interface.*/
 857         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 858
 859         dbfs_atomic_inc(&cnt.num_connect_req);
 860         cf_sk->layer.receive = caif_sktrecv_cb;
 861
 862         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 863                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
 864
 865         if (err < 0) {
 866                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 867                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 868                 goto out;
 869         }
 870
 871         err = -ENODEV;
 872         rcu_read_lock();
 873         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 874         if (!dev) {
 875                 rcu_read_unlock();
 876                 goto out;
 877         }
 878         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 879         mtu = dev->mtu;
 880         rcu_read_unlock();
 881
 882         cf_sk->tailroom = tailroom;
 883         cf_sk->maxframe = mtu - (headroom + tailroom);
 884         if (cf_sk->maxframe < 1) {
 885                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 886                 err = -ENODEV;
 887                 goto out;
 888         }
 889
 890         err = -EINPROGRESS;
 891 wait_connect:
 892
 893         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 894                 goto out;
 895
 896         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 897
 898         release_sock(sk);
 899         err = -ERESTARTSYS;
 900         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 901                         sk->sk_state != CAIF_CONNECTING,
 902                         timeo);
 903         lock_sock(sk);
 904         if (timeo < 0)
 905                 goto out; /* -ERESTARTSYS */
 906
 907         err = -ETIMEDOUT;
 908         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 909                 goto out;
 910         if (sk->sk_state != CAIF_CONNECTED) {
 911                 sock->state = SS_UNCONNECTED;
 912                 err = sock_error(sk);
 913                 if (!err)
 914                         err = -ECONNREFUSED;
 915                 goto out;
 916         }
 917         sock->state = SS_CONNECTED;
 918         err = 0;
 919 out:
 920         release_sock(sk);
 921         return err;
 922 }
 923
 924 /*
 925  * caif_release() - Disconnect a CAIF Socket
 926  * Copied and modified af_irda.c:irda_release().
 927  */
 928 static int caif_release(struct socket *sock)
 929 {
 930         struct sock *sk = sock->sk;
 931         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 932
 933         if (!sk)
 934                 return 0;
 935
 936         set_tx_flow_off(cf_sk);
 937
 938         /*
 939          * Ensure that packets are not queued after this point in time.
 940          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 941          * this ensures no packets when sock is dead.
 942          */
 943         spin_lock_bh(&sk->sk_receive_queue.lock);
 944         sock_set_flag(sk, SOCK_DEAD);
 945         spin_unlock_bh(&sk->sk_receive_queue.lock);
 946         sock->sk = NULL;
 947
 948         dbfs_atomic_inc(&cnt.num_disconnect);
 949
 950         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 951         if (cf_sk->debugfs_socket_dir != NULL)
 952                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 953
 954         lock_sock(&(cf_sk->sk));
 955         sk->sk_state = CAIF_DISCONNECTED;
 956         sk->sk_shutdown = SHUTDOWN_MASK;
 957
 958         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 959         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 960         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 961
 962         sock_orphan(sk);
 963         sk_stream_kill_queues(&cf_sk->sk);
 964         release_sock(sk);
 965         sock_put(sk);
 966         return 0;
 967 }
 968
 969 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 970 static unsigned int caif_poll(struct file *file,
 971                                 struct socket *sock, poll_table *wait)
 972 {
 973         struct sock *sk = sock->sk;
 974         unsigned int mask;
 975         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 976
 977         sock_poll_wait(file, sk_sleep(sk), wait);
 978         mask = 0;
 979
 980         /* exceptional events? */
 981         if (sk->sk_err)
 982                 mask |= POLLERR;
 983         if (sk->sk_shutdown == SHUTDOWN_MASK)
 984                 mask |= POLLHUP;
 985         if (sk->sk_shutdown & RCV_SHUTDOWN)
 986                 mask |= POLLRDHUP;
 987
 988         /* readable? */
 989         if (!skb_queue_empty(&sk->sk_receive_queue) ||
 990                 (sk->sk_shutdown & RCV_SHUTDOWN))
 991                 mask |= POLLIN | POLLRDNORM;
 992
 993         /*
 994          * we set writable also when the other side has shut down the
 995          * connection. This prevents stuck sockets.
 996          */
 997         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 998                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 999
1000         return mask;
1001 }
1002
1003 static const struct proto_ops caif_seqpacket_ops = {
1004         .family = PF_CAIF,
1005         .owner = THIS_MODULE,
1006         .release = caif_release,
1007         .bind = sock_no_bind,
1008         .connect = caif_connect,
1009         .socketpair = sock_no_socketpair,
1010         .accept = sock_no_accept,
1011         .getname = sock_no_getname,
1012         .poll = caif_poll,
1013         .ioctl = sock_no_ioctl,
1014         .listen = sock_no_listen,
1015         .shutdown = sock_no_shutdown,
1016         .setsockopt = setsockopt,
1017         .getsockopt = sock_no_getsockopt,
1018         .sendmsg = caif_seqpkt_sendmsg,
1019         .recvmsg = caif_seqpkt_recvmsg,
1020         .mmap = sock_no_mmap,
1021         .sendpage = sock_no_sendpage,
1022 };
1023
1024 static const struct proto_ops caif_stream_ops = {
1025         .family = PF_CAIF,
1026         .owner = THIS_MODULE,
1027         .release = caif_release,
1028         .bind = sock_no_bind,
1029         .connect = caif_connect,
1030         .socketpair = sock_no_socketpair,
1031         .accept = sock_no_accept,
1032         .getname = sock_no_getname,
1033         .poll = caif_poll,
1034         .ioctl = sock_no_ioctl,
1035         .listen = sock_no_listen,
1036         .shutdown = sock_no_shutdown,
1037         .setsockopt = setsockopt,
1038         .getsockopt = sock_no_getsockopt,
1039         .sendmsg = caif_stream_sendmsg,
1040         .recvmsg = caif_stream_recvmsg,
1041         .mmap = sock_no_mmap,
1042         .sendpage = sock_no_sendpage,
1043 };
1044
1045 /* This function is called when a socket is finally destroyed. */
1046 static void caif_sock_destructor(struct sock *sk)
1047 {
1048         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1049         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1050         caif_assert(sk_unhashed(sk));
1051         caif_assert(!sk->sk_socket);
1052         if (!sock_flag(sk, SOCK_DEAD)) {
1053                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1054                 return;
1055         }
1056         sk_stream_kill_queues(&cf_sk->sk);
1057         dbfs_atomic_dec(&cnt.caif_nr_socks);
1058         caif_free_client(&cf_sk->layer);
1059 }
1060
1061 static int caif_create(struct net *net, struct socket *sock, int protocol,
1062                         int kern)
1063 {
1064         int num;
1065         struct sock *sk = NULL;
1066         struct caifsock *cf_sk = NULL;
1067         static struct proto prot = {.name = "PF_CAIF",
1068                 .owner = THIS_MODULE,
1069                 .obj_size = sizeof(struct caifsock),
1070         };
1071
1072         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1073                 return -EPERM;
1074         /*
1075          * The sock->type specifies the socket type to use.
1076          * The CAIF socket is a packet stream in the sense
1077          * that it is packet based. CAIF trusts the reliability
1078          * of the link, no resending is implemented.
1079          */
1080         if (sock->type == SOCK_SEQPACKET)
1081                 sock->ops = &caif_seqpacket_ops;
1082         else if (sock->type == SOCK_STREAM)
1083                 sock->ops = &caif_stream_ops;
1084         else
1085                 return -ESOCKTNOSUPPORT;
1086
1087         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1088                 return -EPROTONOSUPPORT;
1089         /*
1090          * Set the socket state to unconnected.  The socket state
1091          * is really not used at all in the net/core or socket.c but the
1092          * initialization makes sure that sock->state is not uninitialized.
1093          */
1094         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1095         if (!sk)
1096                 return -ENOMEM;
1097
1098         cf_sk = container_of(sk, struct caifsock, sk);
1099
1100         /* Store the protocol */
1101         sk->sk_protocol = (unsigned char) protocol;
1102
1103         /*
1104          * Lock in order to try to stop someone from opening the socket
1105          * too early.
1106          */
1107         lock_sock(&(cf_sk->sk));
1108
1109         /* Initialize the nozero default sock structure data. */
1110         sock_init_data(sock, sk);
1111         sk->sk_destruct = caif_sock_destructor;
1112
1113         mutex_init(&cf_sk->readlock); /* single task reading lock */
1114         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1115         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1116         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1117
1118         set_tx_flow_off(cf_sk);
1119         set_rx_flow_on(cf_sk);
1120
1121         /* Set default options on configuration */
1122         cf_sk->sk.sk_priority = CAIF_PRIO_NORMAL;
1123         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1124         cf_sk->conn_req.protocol = protocol;
1125         /* Increase the number of sockets created. */
1126         dbfs_atomic_inc(&cnt.caif_nr_socks);
1127         num = dbfs_atomic_inc(&cnt.caif_sock_create);
1128 #ifdef CONFIG_DEBUG_FS
1129         if (!IS_ERR(debugfsdir)) {
1130
1131                 /* Fill in some information concerning the misc socket. */
1132                 snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d", num);
1133
1134                 cf_sk->debugfs_socket_dir =
1135                         debugfs_create_dir(cf_sk->name, debugfsdir);
1136
1137                 debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
1138                                 cf_sk->debugfs_socket_dir,
1139                                 (u32 *) &cf_sk->sk.sk_state);
1140                 debugfs_create_u32("flow_state", S_IRUSR | S_IWUSR,
1141                                 cf_sk->debugfs_socket_dir, &cf_sk->flow_state);
1142                 debugfs_create_u32("sk_rmem_alloc", S_IRUSR | S_IWUSR,
1143                                 cf_sk->debugfs_socket_dir,
1144                                 (u32 *) &cf_sk->sk.sk_rmem_alloc);
1145                 debugfs_create_u32("sk_wmem_alloc", S_IRUSR | S_IWUSR,
1146                                 cf_sk->debugfs_socket_dir,
1147                                 (u32 *) &cf_sk->sk.sk_wmem_alloc);
1148                 debugfs_create_u32("identity", S_IRUSR | S_IWUSR,
1149                                 cf_sk->debugfs_socket_dir,
1150                                 (u32 *) &cf_sk->layer.id);
1151         }
1152 #endif
1153         release_sock(&cf_sk->sk);
1154         return 0;
1155 }
1156
1157
1158 static struct net_proto_family caif_family_ops = {
1159         .family = PF_CAIF,
1160         .create = caif_create,
1161         .owner = THIS_MODULE,
1162 };
1163
1164 static int af_caif_init(void)
1165 {
1166         int err = sock_register(&caif_family_ops);
1167         if (!err)
1168                 return err;
1169         return 0;
1170 }
1171
1172 static int __init caif_sktinit_module(void)
1173 {
1174 #ifdef CONFIG_DEBUG_FS
1175         debugfsdir = debugfs_create_dir("caif_sk", NULL);
1176         if (!IS_ERR(debugfsdir)) {
1177                 debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
1178                                 debugfsdir,
1179                                 (u32 *) &cnt.caif_nr_socks);
1180                 debugfs_create_u32("num_create", S_IRUSR | S_IWUSR,
1181                                 debugfsdir,
1182                                 (u32 *) &cnt.caif_sock_create);
1183                 debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
1184                                 debugfsdir,
1185                                 (u32 *) &cnt.num_connect_req);
1186                 debugfs_create_u32("num_connect_resp", S_IRUSR | S_IWUSR,
1187                                 debugfsdir,
1188                                 (u32 *) &cnt.num_connect_resp);
1189                 debugfs_create_u32("num_connect_fail_resp", S_IRUSR | S_IWUSR,
1190                                 debugfsdir,
1191                                 (u32 *) &cnt.num_connect_fail_resp);
1192                 debugfs_create_u32("num_disconnect", S_IRUSR | S_IWUSR,
1193                                 debugfsdir,
1194                                 (u32 *) &cnt.num_disconnect);
1195                 debugfs_create_u32("num_remote_shutdown_ind",
1196                                 S_IRUSR | S_IWUSR, debugfsdir,
1197                                 (u32 *) &cnt.num_remote_shutdown_ind);
1198                 debugfs_create_u32("num_tx_flow_off_ind", S_IRUSR | S_IWUSR,
1199                                 debugfsdir,
1200                                 (u32 *) &cnt.num_tx_flow_off_ind);
1201                 debugfs_create_u32("num_tx_flow_on_ind", S_IRUSR | S_IWUSR,
1202                                 debugfsdir,
1203                                 (u32 *) &cnt.num_tx_flow_on_ind);
1204                 debugfs_create_u32("num_rx_flow_off", S_IRUSR | S_IWUSR,
1205                                 debugfsdir,
1206                                 (u32 *) &cnt.num_rx_flow_off);
1207                 debugfs_create_u32("num_rx_flow_on", S_IRUSR | S_IWUSR,
1208                                 debugfsdir,
1209                                 (u32 *) &cnt.num_rx_flow_on);
1210         }
1211 #endif
1212         return af_caif_init();
1213 }
1214
1215 static void __exit caif_sktexit_module(void)
1216 {
1217         sock_unregister(PF_CAIF);
1218         if (debugfsdir != NULL)
1219                 debugfs_remove_recursive(debugfsdir);
1220 }
1221 module_init(caif_sktinit_module);
1222 module_exit(caif_sktexit_module);