linux/net/caif/caif_socket.c
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   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
  29MODULE_LICENSE("GPL");
  30MODULE_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 */
  37enum 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
  46static struct dentry *debugfsdir;
  47
  48#ifdef CONFIG_DEBUG_FS
  49struct 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};
  61static 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
  69struct 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
  80static 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
  86static 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
  92static 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
  98static 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
 104static 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
 110static 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
 116static 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
 123static 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
 130static 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
 136static 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 */
 148static 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 */
 196static 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 */
 213static 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
 276static 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 */
 294static 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;
 321out_free:
 322        skb_free_datagram(sk, skb);
 323        caif_check_flow_release(sk);
 324        return ret;
 325
 326read_error:
 327        return ret;
 328}
 329
 330
 331/* Copied from unix_stream_wait_data, identical except for lock call. */
 332static 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 */
 366static 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;
 437unlock:
 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
 474out:
 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 */
 482static 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 */
 518static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 519                        int noblock, long timeo)
 520{
 521        struct cfpkt *pkt;
 522        int ret, loopcnt = 0;
 523
 524        pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 525        memset(cfpkt_info(pkt), 0, sizeof(struct caif_payload_info));
 526        do {
 527
 528                ret = -ETIMEDOUT;
 529
 530                /* Slight paranoia, probably not needed. */
 531                if (unlikely(loopcnt++ > 1000)) {
 532                        pr_warn("transmit retries failed, error = %d\n", ret);
 533                        break;
 534                }
 535
 536                if (cf_sk->layer.dn != NULL)
 537                        ret = cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 538                if (likely(ret >= 0))
 539                        break;
 540                /* if transmit return -EAGAIN, then retry */
 541                if (noblock && ret == -EAGAIN)
 542                        break;
 543                timeo = caif_wait_for_flow_on(cf_sk, 0, timeo, &ret);
 544                if (signal_pending(current)) {
 545                        ret = sock_intr_errno(timeo);
 546                        break;
 547                }
 548                if (ret)
 549                        break;
 550                if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 551                        sock_flag(&cf_sk->sk, SOCK_DEAD) ||
 552                        (cf_sk->sk.sk_shutdown & RCV_SHUTDOWN)) {
 553                        ret = -EPIPE;
 554                        cf_sk->sk.sk_err = EPIPE;
 555                        break;
 556                }
 557        } while (ret == -EAGAIN);
 558        return ret;
 559}
 560
 561/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 562static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 563                        struct msghdr *msg, size_t len)
 564{
 565        struct sock *sk = sock->sk;
 566        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 567        int buffer_size;
 568        int ret = 0;
 569        struct sk_buff *skb = NULL;
 570        int noblock;
 571        long timeo;
 572        caif_assert(cf_sk);
 573        ret = sock_error(sk);
 574        if (ret)
 575                goto err;
 576
 577        ret = -EOPNOTSUPP;
 578        if (msg->msg_flags&MSG_OOB)
 579                goto err;
 580
 581        ret = -EOPNOTSUPP;
 582        if (msg->msg_namelen)
 583                goto err;
 584
 585        ret = -EINVAL;
 586        if (unlikely(msg->msg_iov->iov_base == NULL))
 587                goto err;
 588        noblock = msg->msg_flags & MSG_DONTWAIT;
 589
 590        timeo = sock_sndtimeo(sk, noblock);
 591        timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 592                                1, timeo, &ret);
 593
 594        if (ret)
 595                goto err;
 596        ret = -EPIPE;
 597        if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 598                sock_flag(sk, SOCK_DEAD) ||
 599                (sk->sk_shutdown & RCV_SHUTDOWN))
 600                goto err;
 601
 602        /* Error if trying to write more than maximum frame size. */
 603        ret = -EMSGSIZE;
 604        if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 605                goto err;
 606
 607        buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 608
 609        ret = -ENOMEM;
 610        skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 611
 612        if (!skb || skb_tailroom(skb) < buffer_size)
 613                goto err;
 614
 615        skb_reserve(skb, cf_sk->headroom);
 616
 617        ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 618
 619        if (ret)
 620                goto err;
 621        ret = transmit_skb(skb, cf_sk, noblock, timeo);
 622        if (ret < 0)
 623                goto err;
 624        return len;
 625err:
 626        kfree_skb(skb);
 627        return ret;
 628}
 629
 630/*
 631 * Copied from unix_stream_sendmsg and adapted to CAIF:
 632 * Changed removed permission handling and added waiting for flow on
 633 * and other minor adaptations.
 634 */
 635static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 636                                struct msghdr *msg, size_t len)
 637{
 638        struct sock *sk = sock->sk;
 639        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 640        int err, size;
 641        struct sk_buff *skb;
 642        int sent = 0;
 643        long timeo;
 644
 645        err = -EOPNOTSUPP;
 646        if (unlikely(msg->msg_flags&MSG_OOB))
 647                goto out_err;
 648
 649        if (unlikely(msg->msg_namelen))
 650                goto out_err;
 651
 652        timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 653        timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 654
 655        if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 656                goto pipe_err;
 657
 658        while (sent < len) {
 659
 660                size = len-sent;
 661
 662                if (size > cf_sk->maxframe)
 663                        size = cf_sk->maxframe;
 664
 665                /* If size is more than half of sndbuf, chop up message */
 666                if (size > ((sk->sk_sndbuf >> 1) - 64))
 667                        size = (sk->sk_sndbuf >> 1) - 64;
 668
 669                if (size > SKB_MAX_ALLOC)
 670                        size = SKB_MAX_ALLOC;
 671
 672                skb = sock_alloc_send_skb(sk,
 673                                        size + cf_sk->headroom +
 674                                        cf_sk->tailroom,
 675                                        msg->msg_flags&MSG_DONTWAIT,
 676                                        &err);
 677                if (skb == NULL)
 678                        goto out_err;
 679
 680                skb_reserve(skb, cf_sk->headroom);
 681                /*
 682                 *      If you pass two values to the sock_alloc_send_skb
 683                 *      it tries to grab the large buffer with GFP_NOFS
 684                 *      (which can fail easily), and if it fails grab the
 685                 *      fallback size buffer which is under a page and will
 686                 *      succeed. [Alan]
 687                 */
 688                size = min_t(int, size, skb_tailroom(skb));
 689
 690                err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 691                if (err) {
 692                        kfree_skb(skb);
 693                        goto out_err;
 694                }
 695                err = transmit_skb(skb, cf_sk,
 696                                msg->msg_flags&MSG_DONTWAIT, timeo);
 697                if (err < 0) {
 698                        kfree_skb(skb);
 699                        goto pipe_err;
 700                }
 701                sent += size;
 702        }
 703
 704        return sent;
 705
 706pipe_err:
 707        if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 708                send_sig(SIGPIPE, current, 0);
 709        err = -EPIPE;
 710out_err:
 711        return sent ? : err;
 712}
 713
 714static int setsockopt(struct socket *sock,
 715                        int lvl, int opt, char __user *ov, unsigned int ol)
 716{
 717        struct sock *sk = sock->sk;
 718        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 719        int linksel;
 720
 721        if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 722                return -ENOPROTOOPT;
 723
 724        switch (opt) {
 725        case CAIFSO_LINK_SELECT:
 726                if (ol < sizeof(int))
 727                        return -EINVAL;
 728                if (lvl != SOL_CAIF)
 729                        goto bad_sol;
 730                if (copy_from_user(&linksel, ov, sizeof(int)))
 731                        return -EINVAL;
 732                lock_sock(&(cf_sk->sk));
 733                cf_sk->conn_req.link_selector = linksel;
 734                release_sock(&cf_sk->sk);
 735                return 0;
 736
 737        case CAIFSO_REQ_PARAM:
 738                if (lvl != SOL_CAIF)
 739                        goto bad_sol;
 740                if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 741                        return -ENOPROTOOPT;
 742                lock_sock(&(cf_sk->sk));
 743                cf_sk->conn_req.param.size = ol;
 744                if (ol > sizeof(cf_sk->conn_req.param.data) ||
 745                        copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 746                        release_sock(&cf_sk->sk);
 747                        return -EINVAL;
 748                }
 749                release_sock(&cf_sk->sk);
 750                return 0;
 751
 752        default:
 753                return -ENOPROTOOPT;
 754        }
 755
 756        return 0;
 757bad_sol:
 758        return -ENOPROTOOPT;
 759
 760}
 761
 762/*
 763 * caif_connect() - Connect a CAIF Socket
 764 * Copied and modified af_irda.c:irda_connect().
 765 *
 766 * Note : by consulting "errno", the user space caller may learn the cause
 767 * of the failure. Most of them are visible in the function, others may come
 768 * from subroutines called and are listed here :
 769 *  o -EAFNOSUPPORT: bad socket family or type.
 770 *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 771 *  o -EINVAL: bad socket address, or CAIF link type
 772 *  o -ECONNREFUSED: remote end refused the connection.
 773 *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 774 *  o -EISCONN: already connected.
 775 *  o -ETIMEDOUT: Connection timed out (send timeout)
 776 *  o -ENODEV: No link layer to send request
 777 *  o -ECONNRESET: Received Shutdown indication or lost link layer
 778 *  o -ENOMEM: Out of memory
 779 *
 780 *  State Strategy:
 781 *  o sk_state: holds the CAIF_* protocol state, it's updated by
 782 *      caif_ctrl_cb.
 783 *  o sock->state: holds the SS_* socket state and is updated by connect and
 784 *      disconnect.
 785 */
 786static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 787                        int addr_len, int flags)
 788{
 789        struct sock *sk = sock->sk;
 790        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 791        long timeo;
 792        int err;
 793        int ifindex, headroom, tailroom;
 794        unsigned int mtu;
 795        struct net_device *dev;
 796
 797        lock_sock(sk);
 798
 799        err = -EAFNOSUPPORT;
 800        if (uaddr->sa_family != AF_CAIF)
 801                goto out;
 802
 803        switch (sock->state) {
 804        case SS_UNCONNECTED:
 805                /* Normal case, a fresh connect */
 806                caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 807                break;
 808        case SS_CONNECTING:
 809                switch (sk->sk_state) {
 810                case CAIF_CONNECTED:
 811                        sock->state = SS_CONNECTED;
 812                        err = -EISCONN;
 813                        goto out;
 814                case CAIF_DISCONNECTED:
 815                        /* Reconnect allowed */
 816                        break;
 817                case CAIF_CONNECTING:
 818                        err = -EALREADY;
 819                        if (flags & O_NONBLOCK)
 820                                goto out;
 821                        goto wait_connect;
 822                }
 823                break;
 824        case SS_CONNECTED:
 825                caif_assert(sk->sk_state == CAIF_CONNECTED ||
 826                                sk->sk_state == CAIF_DISCONNECTED);
 827                if (sk->sk_shutdown & SHUTDOWN_MASK) {
 828                        /* Allow re-connect after SHUTDOWN_IND */
 829                        caif_disconnect_client(&cf_sk->layer);
 830                        break;
 831                }
 832                /* No reconnect on a seqpacket socket */
 833                err = -EISCONN;
 834                goto out;
 835        case SS_DISCONNECTING:
 836        case SS_FREE:
 837                caif_assert(1); /*Should never happen */
 838                break;
 839        }
 840        sk->sk_state = CAIF_DISCONNECTED;
 841        sock->state = SS_UNCONNECTED;
 842        sk_stream_kill_queues(&cf_sk->sk);
 843
 844        err = -EINVAL;
 845        if (addr_len != sizeof(struct sockaddr_caif))
 846                goto out;
 847
 848        memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 849                sizeof(struct sockaddr_caif));
 850
 851        /* Move to connecting socket, start sending Connect Requests */
 852        sock->state = SS_CONNECTING;
 853        sk->sk_state = CAIF_CONNECTING;
 854
 855        /* Check priority value comming from socket */
 856        /* if priority value is out of range it will be ajusted */
 857        if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 858                cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 859        else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 860                cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 861        else
 862                cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 863
 864        /*ifindex = id of the interface.*/
 865        cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 866
 867        dbfs_atomic_inc(&cnt.num_connect_req);
 868        cf_sk->layer.receive = caif_sktrecv_cb;
 869        err = caif_connect_client(&cf_sk->conn_req,
 870                                &cf_sk->layer, &ifindex, &headroom, &tailroom);
 871        if (err < 0) {
 872                cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 873                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 874                goto out;
 875        }
 876
 877        err = -ENODEV;
 878        rcu_read_lock();
 879        dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 880        if (!dev) {
 881                rcu_read_unlock();
 882                goto out;
 883        }
 884        cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 885        mtu = dev->mtu;
 886        rcu_read_unlock();
 887
 888        cf_sk->tailroom = tailroom;
 889        cf_sk->maxframe = mtu - (headroom + tailroom);
 890        if (cf_sk->maxframe < 1) {
 891                pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 892                err = -ENODEV;
 893                goto out;
 894        }
 895
 896        err = -EINPROGRESS;
 897wait_connect:
 898
 899        if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 900                goto out;
 901
 902        timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 903
 904        release_sock(sk);
 905        err = -ERESTARTSYS;
 906        timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 907                        sk->sk_state != CAIF_CONNECTING,
 908                        timeo);
 909        lock_sock(sk);
 910        if (timeo < 0)
 911                goto out; /* -ERESTARTSYS */
 912
 913        err = -ETIMEDOUT;
 914        if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 915                goto out;
 916        if (sk->sk_state != CAIF_CONNECTED) {
 917                sock->state = SS_UNCONNECTED;
 918                err = sock_error(sk);
 919                if (!err)
 920                        err = -ECONNREFUSED;
 921                goto out;
 922        }
 923        sock->state = SS_CONNECTED;
 924        err = 0;
 925out:
 926        release_sock(sk);
 927        return err;
 928}
 929
 930/*
 931 * caif_release() - Disconnect a CAIF Socket
 932 * Copied and modified af_irda.c:irda_release().
 933 */
 934static int caif_release(struct socket *sock)
 935{
 936        struct sock *sk = sock->sk;
 937        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 938        int res = 0;
 939
 940        if (!sk)
 941                return 0;
 942
 943        set_tx_flow_off(cf_sk);
 944
 945        /*
 946         * Ensure that packets are not queued after this point in time.
 947         * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 948         * this ensures no packets when sock is dead.
 949         */
 950        spin_lock(&sk->sk_receive_queue.lock);
 951        sock_set_flag(sk, SOCK_DEAD);
 952        spin_unlock(&sk->sk_receive_queue.lock);
 953        sock->sk = NULL;
 954
 955        dbfs_atomic_inc(&cnt.num_disconnect);
 956
 957        if (cf_sk->debugfs_socket_dir != NULL)
 958                debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 959
 960        lock_sock(&(cf_sk->sk));
 961        sk->sk_state = CAIF_DISCONNECTED;
 962        sk->sk_shutdown = SHUTDOWN_MASK;
 963
 964        if (cf_sk->sk.sk_socket->state == SS_CONNECTED ||
 965                cf_sk->sk.sk_socket->state == SS_CONNECTING)
 966                res = caif_disconnect_client(&cf_sk->layer);
 967
 968        cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 969        wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 970
 971        sock_orphan(sk);
 972        cf_sk->layer.dn = NULL;
 973        sk_stream_kill_queues(&cf_sk->sk);
 974        release_sock(sk);
 975        sock_put(sk);
 976        return res;
 977}
 978
 979/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 980static unsigned int caif_poll(struct file *file,
 981                                struct socket *sock, poll_table *wait)
 982{
 983        struct sock *sk = sock->sk;
 984        unsigned int mask;
 985        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 986
 987        sock_poll_wait(file, sk_sleep(sk), wait);
 988        mask = 0;
 989
 990        /* exceptional events? */
 991        if (sk->sk_err)
 992                mask |= POLLERR;
 993        if (sk->sk_shutdown == SHUTDOWN_MASK)
 994                mask |= POLLHUP;
 995        if (sk->sk_shutdown & RCV_SHUTDOWN)
 996                mask |= POLLRDHUP;
 997
 998        /* readable? */
 999        if (!skb_queue_empty(&sk->sk_receive_queue) ||
1000                (sk->sk_shutdown & RCV_SHUTDOWN))
1001                mask |= POLLIN | POLLRDNORM;
1002
1003        /*
1004         * we set writable also when the other side has shut down the
1005         * connection. This prevents stuck sockets.
1006         */
1007        if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
1008                mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
1009
1010        return mask;
1011}
1012
1013static const struct proto_ops caif_seqpacket_ops = {
1014        .family = PF_CAIF,
1015        .owner = THIS_MODULE,
1016        .release = caif_release,
1017        .bind = sock_no_bind,
1018        .connect = caif_connect,
1019        .socketpair = sock_no_socketpair,
1020        .accept = sock_no_accept,
1021        .getname = sock_no_getname,
1022        .poll = caif_poll,
1023        .ioctl = sock_no_ioctl,
1024        .listen = sock_no_listen,
1025        .shutdown = sock_no_shutdown,
1026        .setsockopt = setsockopt,
1027        .getsockopt = sock_no_getsockopt,
1028        .sendmsg = caif_seqpkt_sendmsg,
1029        .recvmsg = caif_seqpkt_recvmsg,
1030        .mmap = sock_no_mmap,
1031        .sendpage = sock_no_sendpage,
1032};
1033
1034static const struct proto_ops caif_stream_ops = {
1035        .family = PF_CAIF,
1036        .owner = THIS_MODULE,
1037        .release = caif_release,
1038        .bind = sock_no_bind,
1039        .connect = caif_connect,
1040        .socketpair = sock_no_socketpair,
1041        .accept = sock_no_accept,
1042        .getname = sock_no_getname,
1043        .poll = caif_poll,
1044        .ioctl = sock_no_ioctl,
1045        .listen = sock_no_listen,
1046        .shutdown = sock_no_shutdown,
1047        .setsockopt = setsockopt,
1048        .getsockopt = sock_no_getsockopt,
1049        .sendmsg = caif_stream_sendmsg,
1050        .recvmsg = caif_stream_recvmsg,
1051        .mmap = sock_no_mmap,
1052        .sendpage = sock_no_sendpage,
1053};
1054
1055/* This function is called when a socket is finally destroyed. */
1056static void caif_sock_destructor(struct sock *sk)
1057{
1058        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1059        caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1060        caif_assert(sk_unhashed(sk));
1061        caif_assert(!sk->sk_socket);
1062        if (!sock_flag(sk, SOCK_DEAD)) {
1063                pr_info("Attempt to release alive CAIF socket: %p\n", sk);
1064                return;
1065        }
1066        sk_stream_kill_queues(&cf_sk->sk);
1067        dbfs_atomic_dec(&cnt.caif_nr_socks);
1068}
1069
1070static int caif_create(struct net *net, struct socket *sock, int protocol,
1071                        int kern)
1072{
1073        struct sock *sk = NULL;
1074        struct caifsock *cf_sk = NULL;
1075        static struct proto prot = {.name = "PF_CAIF",
1076                .owner = THIS_MODULE,
1077                .obj_size = sizeof(struct caifsock),
1078        };
1079
1080        if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1081                return -EPERM;
1082        /*
1083         * The sock->type specifies the socket type to use.
1084         * The CAIF socket is a packet stream in the sense
1085         * that it is packet based. CAIF trusts the reliability
1086         * of the link, no resending is implemented.
1087         */
1088        if (sock->type == SOCK_SEQPACKET)
1089                sock->ops = &caif_seqpacket_ops;
1090        else if (sock->type == SOCK_STREAM)
1091                sock->ops = &caif_stream_ops;
1092        else
1093                return -ESOCKTNOSUPPORT;
1094
1095        if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1096                return -EPROTONOSUPPORT;
1097        /*
1098         * Set the socket state to unconnected.  The socket state
1099         * is really not used at all in the net/core or socket.c but the
1100         * initialization makes sure that sock->state is not uninitialized.
1101         */
1102        sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1103        if (!sk)
1104                return -ENOMEM;
1105
1106        cf_sk = container_of(sk, struct caifsock, sk);
1107
1108        /* Store the protocol */
1109        sk->sk_protocol = (unsigned char) protocol;
1110
1111        /*
1112         * Lock in order to try to stop someone from opening the socket
1113         * too early.
1114         */
1115        lock_sock(&(cf_sk->sk));
1116
1117        /* Initialize the nozero default sock structure data. */
1118        sock_init_data(sock, sk);
1119        sk->sk_destruct = caif_sock_destructor;
1120
1121        mutex_init(&cf_sk->readlock); /* single task reading lock */
1122        cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1123        cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1124        cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1125
1126        set_tx_flow_off(cf_sk);
1127        set_rx_flow_on(cf_sk);
1128
1129        /* Set default options on configuration */
1130        cf_sk->sk.sk_priority= CAIF_PRIO_NORMAL;
1131        cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1132        cf_sk->conn_req.protocol = protocol;
1133        /* Increase the number of sockets created. */
1134        dbfs_atomic_inc(&cnt.caif_nr_socks);
1135#ifdef CONFIG_DEBUG_FS
1136        if (!IS_ERR(debugfsdir)) {
1137                /* Fill in some information concerning the misc socket. */
1138                snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d",
1139                                atomic_read(&cnt.caif_nr_socks));
1140
1141                cf_sk->debugfs_socket_dir =
1142                        debugfs_create_dir(cf_sk->name, debugfsdir);
1143                debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
1144                                cf_sk->debugfs_socket_dir,
1145                                (u32 *) &cf_sk->sk.sk_state);
1146                debugfs_create_u32("flow_state", S_IRUSR | S_IWUSR,
1147                                cf_sk->debugfs_socket_dir, &cf_sk->flow_state);
1148                debugfs_create_u32("sk_rmem_alloc", S_IRUSR | S_IWUSR,
1149                                cf_sk->debugfs_socket_dir,
1150                                (u32 *) &cf_sk->sk.sk_rmem_alloc);
1151                debugfs_create_u32("sk_wmem_alloc", S_IRUSR | S_IWUSR,
1152                                cf_sk->debugfs_socket_dir,
1153                                (u32 *) &cf_sk->sk.sk_wmem_alloc);
1154                debugfs_create_u32("identity", S_IRUSR | S_IWUSR,
1155                                cf_sk->debugfs_socket_dir,
1156                                (u32 *) &cf_sk->layer.id);
1157        }
1158#endif
1159        release_sock(&cf_sk->sk);
1160        return 0;
1161}
1162
1163
1164static struct net_proto_family caif_family_ops = {
1165        .family = PF_CAIF,
1166        .create = caif_create,
1167        .owner = THIS_MODULE,
1168};
1169
1170static int af_caif_init(void)
1171{
1172        int err = sock_register(&caif_family_ops);
1173        if (!err)
1174                return err;
1175        return 0;
1176}
1177
1178static int __init caif_sktinit_module(void)
1179{
1180#ifdef CONFIG_DEBUG_FS
1181        debugfsdir = debugfs_create_dir("caif_sk", NULL);
1182        if (!IS_ERR(debugfsdir)) {
1183                debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
1184                                debugfsdir,
1185                                (u32 *) &cnt.caif_nr_socks);
1186                debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
1187                                debugfsdir,
1188                                (u32 *) &cnt.num_connect_req);
1189                debugfs_create_u32("num_connect_resp", S_IRUSR | S_IWUSR,
1190                                debugfsdir,
1191                                (u32 *) &cnt.num_connect_resp);
1192                debugfs_create_u32("num_connect_fail_resp", S_IRUSR | S_IWUSR,
1193                                debugfsdir,
1194                                (u32 *) &cnt.num_connect_fail_resp);
1195                debugfs_create_u32("num_disconnect", S_IRUSR | S_IWUSR,
1196                                debugfsdir,
1197                                (u32 *) &cnt.num_disconnect);
1198                debugfs_create_u32("num_remote_shutdown_ind",
1199                                S_IRUSR | S_IWUSR, debugfsdir,
1200                                (u32 *) &cnt.num_remote_shutdown_ind);
1201                debugfs_create_u32("num_tx_flow_off_ind", S_IRUSR | S_IWUSR,
1202                                debugfsdir,
1203                                (u32 *) &cnt.num_tx_flow_off_ind);
1204                debugfs_create_u32("num_tx_flow_on_ind", S_IRUSR | S_IWUSR,
1205                                debugfsdir,
1206                                (u32 *) &cnt.num_tx_flow_on_ind);
1207                debugfs_create_u32("num_rx_flow_off", S_IRUSR | S_IWUSR,
1208                                debugfsdir,
1209                                (u32 *) &cnt.num_rx_flow_off);
1210                debugfs_create_u32("num_rx_flow_on", S_IRUSR | S_IWUSR,
1211                                debugfsdir,
1212                                (u32 *) &cnt.num_rx_flow_on);
1213        }
1214#endif
1215        return af_caif_init();
1216}
1217
1218static void __exit caif_sktexit_module(void)
1219{
1220        sock_unregister(PF_CAIF);
1221        if (debugfsdir != NULL)
1222                debugfs_remove_recursive(debugfsdir);
1223}
1224module_init(caif_sktinit_module);
1225module_exit(caif_sktexit_module);
1226