linux/net/caif/caif_socket.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) ST-Ericsson AB 2010
   4 * Author:      Sjur Brendeland
   5 */
   6
   7#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9#include <linux/fs.h>
  10#include <linux/init.h>
  11#include <linux/module.h>
  12#include <linux/sched/signal.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/pkt_sched.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
  46struct caifsock {
  47        struct sock sk; /* must be first member */
  48        struct cflayer layer;
  49        u32 flow_state;
  50        struct caif_connect_request conn_req;
  51        struct mutex readlock;
  52        struct dentry *debugfs_socket_dir;
  53        int headroom, tailroom, maxframe;
  54};
  55
  56static int rx_flow_is_on(struct caifsock *cf_sk)
  57{
  58        return test_bit(RX_FLOW_ON_BIT,
  59                        (void *) &cf_sk->flow_state);
  60}
  61
  62static int tx_flow_is_on(struct caifsock *cf_sk)
  63{
  64        return test_bit(TX_FLOW_ON_BIT,
  65                        (void *) &cf_sk->flow_state);
  66}
  67
  68static void set_rx_flow_off(struct caifsock *cf_sk)
  69{
  70         clear_bit(RX_FLOW_ON_BIT,
  71                 (void *) &cf_sk->flow_state);
  72}
  73
  74static void set_rx_flow_on(struct caifsock *cf_sk)
  75{
  76         set_bit(RX_FLOW_ON_BIT,
  77                        (void *) &cf_sk->flow_state);
  78}
  79
  80static void set_tx_flow_off(struct caifsock *cf_sk)
  81{
  82         clear_bit(TX_FLOW_ON_BIT,
  83                (void *) &cf_sk->flow_state);
  84}
  85
  86static void set_tx_flow_on(struct caifsock *cf_sk)
  87{
  88         set_bit(TX_FLOW_ON_BIT,
  89                (void *) &cf_sk->flow_state);
  90}
  91
  92static void caif_read_lock(struct sock *sk)
  93{
  94        struct caifsock *cf_sk;
  95        cf_sk = container_of(sk, struct caifsock, sk);
  96        mutex_lock(&cf_sk->readlock);
  97}
  98
  99static void caif_read_unlock(struct sock *sk)
 100{
 101        struct caifsock *cf_sk;
 102        cf_sk = container_of(sk, struct caifsock, sk);
 103        mutex_unlock(&cf_sk->readlock);
 104}
 105
 106static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
 107{
 108        /* A quarter of full buffer is used a low water mark */
 109        return cf_sk->sk.sk_rcvbuf / 4;
 110}
 111
 112static void caif_flow_ctrl(struct sock *sk, int mode)
 113{
 114        struct caifsock *cf_sk;
 115        cf_sk = container_of(sk, struct caifsock, sk);
 116        if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
 117                cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
 118}
 119
 120/*
 121 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
 122 * not dropped, but CAIF is sending flow off instead.
 123 */
 124static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 125{
 126        int err;
 127        unsigned long flags;
 128        struct sk_buff_head *list = &sk->sk_receive_queue;
 129        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 130        bool queued = false;
 131
 132        if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 133                (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
 134                net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
 135                                    atomic_read(&cf_sk->sk.sk_rmem_alloc),
 136                                    sk_rcvbuf_lowwater(cf_sk));
 137                set_rx_flow_off(cf_sk);
 138                caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 139        }
 140
 141        err = sk_filter(sk, skb);
 142        if (err)
 143                goto out;
 144
 145        if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
 146                set_rx_flow_off(cf_sk);
 147                net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
 148                caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 149        }
 150        skb->dev = NULL;
 151        skb_set_owner_r(skb, sk);
 152        spin_lock_irqsave(&list->lock, flags);
 153        queued = !sock_flag(sk, SOCK_DEAD);
 154        if (queued)
 155                __skb_queue_tail(list, skb);
 156        spin_unlock_irqrestore(&list->lock, flags);
 157out:
 158        if (queued)
 159                sk->sk_data_ready(sk);
 160        else
 161                kfree_skb(skb);
 162}
 163
 164/* Packet Receive Callback function called from CAIF Stack */
 165static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
 166{
 167        struct caifsock *cf_sk;
 168        struct sk_buff *skb;
 169
 170        cf_sk = container_of(layr, struct caifsock, layer);
 171        skb = cfpkt_tonative(pkt);
 172
 173        if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
 174                kfree_skb(skb);
 175                return 0;
 176        }
 177        caif_queue_rcv_skb(&cf_sk->sk, skb);
 178        return 0;
 179}
 180
 181static void cfsk_hold(struct cflayer *layr)
 182{
 183        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 184        sock_hold(&cf_sk->sk);
 185}
 186
 187static void cfsk_put(struct cflayer *layr)
 188{
 189        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 190        sock_put(&cf_sk->sk);
 191}
 192
 193/* Packet Control Callback function called from CAIF */
 194static void caif_ctrl_cb(struct cflayer *layr,
 195                         enum caif_ctrlcmd flow,
 196                         int phyid)
 197{
 198        struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
 199        switch (flow) {
 200        case CAIF_CTRLCMD_FLOW_ON_IND:
 201                /* OK from modem to start sending again */
 202                set_tx_flow_on(cf_sk);
 203                cf_sk->sk.sk_state_change(&cf_sk->sk);
 204                break;
 205
 206        case CAIF_CTRLCMD_FLOW_OFF_IND:
 207                /* Modem asks us to shut up */
 208                set_tx_flow_off(cf_sk);
 209                cf_sk->sk.sk_state_change(&cf_sk->sk);
 210                break;
 211
 212        case CAIF_CTRLCMD_INIT_RSP:
 213                /* We're now connected */
 214                caif_client_register_refcnt(&cf_sk->layer,
 215                                                cfsk_hold, cfsk_put);
 216                cf_sk->sk.sk_state = CAIF_CONNECTED;
 217                set_tx_flow_on(cf_sk);
 218                cf_sk->sk.sk_shutdown = 0;
 219                cf_sk->sk.sk_state_change(&cf_sk->sk);
 220                break;
 221
 222        case CAIF_CTRLCMD_DEINIT_RSP:
 223                /* We're now disconnected */
 224                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 225                cf_sk->sk.sk_state_change(&cf_sk->sk);
 226                break;
 227
 228        case CAIF_CTRLCMD_INIT_FAIL_RSP:
 229                /* Connect request failed */
 230                cf_sk->sk.sk_err = ECONNREFUSED;
 231                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 232                cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 233                /*
 234                 * Socket "standards" seems to require POLLOUT to
 235                 * be set at connect failure.
 236                 */
 237                set_tx_flow_on(cf_sk);
 238                cf_sk->sk.sk_state_change(&cf_sk->sk);
 239                break;
 240
 241        case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 242                /* Modem has closed this connection, or device is down. */
 243                cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
 244                cf_sk->sk.sk_err = ECONNRESET;
 245                set_rx_flow_on(cf_sk);
 246                cf_sk->sk.sk_error_report(&cf_sk->sk);
 247                break;
 248
 249        default:
 250                pr_debug("Unexpected flow command %d\n", flow);
 251        }
 252}
 253
 254static void caif_check_flow_release(struct sock *sk)
 255{
 256        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 257
 258        if (rx_flow_is_on(cf_sk))
 259                return;
 260
 261        if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
 262                        set_rx_flow_on(cf_sk);
 263                        caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
 264        }
 265}
 266
 267/*
 268 * Copied from unix_dgram_recvmsg, but removed credit checks,
 269 * changed locking, address handling and added MSG_TRUNC.
 270 */
 271static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
 272                               size_t len, int flags)
 273
 274{
 275        struct sock *sk = sock->sk;
 276        struct sk_buff *skb;
 277        int ret;
 278        int copylen;
 279
 280        ret = -EOPNOTSUPP;
 281        if (flags & MSG_OOB)
 282                goto read_error;
 283
 284        skb = skb_recv_datagram(sk, flags, 0 , &ret);
 285        if (!skb)
 286                goto read_error;
 287        copylen = skb->len;
 288        if (len < copylen) {
 289                m->msg_flags |= MSG_TRUNC;
 290                copylen = len;
 291        }
 292
 293        ret = skb_copy_datagram_msg(skb, 0, m, copylen);
 294        if (ret)
 295                goto out_free;
 296
 297        ret = (flags & MSG_TRUNC) ? skb->len : copylen;
 298out_free:
 299        skb_free_datagram(sk, skb);
 300        caif_check_flow_release(sk);
 301        return ret;
 302
 303read_error:
 304        return ret;
 305}
 306
 307
 308/* Copied from unix_stream_wait_data, identical except for lock call. */
 309static long caif_stream_data_wait(struct sock *sk, long timeo)
 310{
 311        DEFINE_WAIT(wait);
 312        lock_sock(sk);
 313
 314        for (;;) {
 315                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 316
 317                if (!skb_queue_empty(&sk->sk_receive_queue) ||
 318                        sk->sk_err ||
 319                        sk->sk_state != CAIF_CONNECTED ||
 320                        sock_flag(sk, SOCK_DEAD) ||
 321                        (sk->sk_shutdown & RCV_SHUTDOWN) ||
 322                        signal_pending(current) ||
 323                        !timeo)
 324                        break;
 325
 326                sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 327                release_sock(sk);
 328                timeo = schedule_timeout(timeo);
 329                lock_sock(sk);
 330
 331                if (sock_flag(sk, SOCK_DEAD))
 332                        break;
 333
 334                sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 335        }
 336
 337        finish_wait(sk_sleep(sk), &wait);
 338        release_sock(sk);
 339        return timeo;
 340}
 341
 342
 343/*
 344 * Copied from unix_stream_recvmsg, but removed credit checks,
 345 * changed locking calls, changed address handling.
 346 */
 347static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 348                               size_t size, int flags)
 349{
 350        struct sock *sk = sock->sk;
 351        int copied = 0;
 352        int target;
 353        int err = 0;
 354        long timeo;
 355
 356        err = -EOPNOTSUPP;
 357        if (flags&MSG_OOB)
 358                goto out;
 359
 360        /*
 361         * Lock the socket to prevent queue disordering
 362         * while sleeps in memcpy_tomsg
 363         */
 364        err = -EAGAIN;
 365        if (sk->sk_state == CAIF_CONNECTING)
 366                goto out;
 367
 368        caif_read_lock(sk);
 369        target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
 370        timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
 371
 372        do {
 373                int chunk;
 374                struct sk_buff *skb;
 375
 376                lock_sock(sk);
 377                if (sock_flag(sk, SOCK_DEAD)) {
 378                        err = -ECONNRESET;
 379                        goto unlock;
 380                }
 381                skb = skb_dequeue(&sk->sk_receive_queue);
 382                caif_check_flow_release(sk);
 383
 384                if (skb == NULL) {
 385                        if (copied >= target)
 386                                goto unlock;
 387                        /*
 388                         *      POSIX 1003.1g mandates this order.
 389                         */
 390                        err = sock_error(sk);
 391                        if (err)
 392                                goto unlock;
 393                        err = -ECONNRESET;
 394                        if (sk->sk_shutdown & RCV_SHUTDOWN)
 395                                goto unlock;
 396
 397                        err = -EPIPE;
 398                        if (sk->sk_state != CAIF_CONNECTED)
 399                                goto unlock;
 400                        if (sock_flag(sk, SOCK_DEAD))
 401                                goto unlock;
 402
 403                        release_sock(sk);
 404
 405                        err = -EAGAIN;
 406                        if (!timeo)
 407                                break;
 408
 409                        caif_read_unlock(sk);
 410
 411                        timeo = caif_stream_data_wait(sk, timeo);
 412
 413                        if (signal_pending(current)) {
 414                                err = sock_intr_errno(timeo);
 415                                goto out;
 416                        }
 417                        caif_read_lock(sk);
 418                        continue;
 419unlock:
 420                        release_sock(sk);
 421                        break;
 422                }
 423                release_sock(sk);
 424                chunk = min_t(unsigned int, skb->len, size);
 425                if (memcpy_to_msg(msg, skb->data, chunk)) {
 426                        skb_queue_head(&sk->sk_receive_queue, skb);
 427                        if (copied == 0)
 428                                copied = -EFAULT;
 429                        break;
 430                }
 431                copied += chunk;
 432                size -= chunk;
 433
 434                /* Mark read part of skb as used */
 435                if (!(flags & MSG_PEEK)) {
 436                        skb_pull(skb, chunk);
 437
 438                        /* put the skb back if we didn't use it up. */
 439                        if (skb->len) {
 440                                skb_queue_head(&sk->sk_receive_queue, skb);
 441                                break;
 442                        }
 443                        kfree_skb(skb);
 444
 445                } else {
 446                        /*
 447                         * It is questionable, see note in unix_dgram_recvmsg.
 448                         */
 449                        /* put message back and return */
 450                        skb_queue_head(&sk->sk_receive_queue, skb);
 451                        break;
 452                }
 453        } while (size);
 454        caif_read_unlock(sk);
 455
 456out:
 457        return copied ? : err;
 458}
 459
 460/*
 461 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
 462 * CAIF flow-on and sock_writable.
 463 */
 464static long caif_wait_for_flow_on(struct caifsock *cf_sk,
 465                                  int wait_writeable, long timeo, int *err)
 466{
 467        struct sock *sk = &cf_sk->sk;
 468        DEFINE_WAIT(wait);
 469        for (;;) {
 470                *err = 0;
 471                if (tx_flow_is_on(cf_sk) &&
 472                        (!wait_writeable || sock_writeable(&cf_sk->sk)))
 473                        break;
 474                *err = -ETIMEDOUT;
 475                if (!timeo)
 476                        break;
 477                *err = -ERESTARTSYS;
 478                if (signal_pending(current))
 479                        break;
 480                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 481                *err = -ECONNRESET;
 482                if (sk->sk_shutdown & SHUTDOWN_MASK)
 483                        break;
 484                *err = -sk->sk_err;
 485                if (sk->sk_err)
 486                        break;
 487                *err = -EPIPE;
 488                if (cf_sk->sk.sk_state != CAIF_CONNECTED)
 489                        break;
 490                timeo = schedule_timeout(timeo);
 491        }
 492        finish_wait(sk_sleep(sk), &wait);
 493        return timeo;
 494}
 495
 496/*
 497 * Transmit a SKB. The device may temporarily request re-transmission
 498 * by returning EAGAIN.
 499 */
 500static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 501                        int noblock, long timeo)
 502{
 503        struct cfpkt *pkt;
 504
 505        pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 506        memset(skb->cb, 0, sizeof(struct caif_payload_info));
 507        cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
 508
 509        if (cf_sk->layer.dn == NULL) {
 510                kfree_skb(skb);
 511                return -EINVAL;
 512        }
 513
 514        return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 515}
 516
 517/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
 518static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
 519                               size_t len)
 520{
 521        struct sock *sk = sock->sk;
 522        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 523        int buffer_size;
 524        int ret = 0;
 525        struct sk_buff *skb = NULL;
 526        int noblock;
 527        long timeo;
 528        caif_assert(cf_sk);
 529        ret = sock_error(sk);
 530        if (ret)
 531                goto err;
 532
 533        ret = -EOPNOTSUPP;
 534        if (msg->msg_flags&MSG_OOB)
 535                goto err;
 536
 537        ret = -EOPNOTSUPP;
 538        if (msg->msg_namelen)
 539                goto err;
 540
 541        ret = -EINVAL;
 542        if (unlikely(msg->msg_iter.iov->iov_base == NULL))
 543                goto err;
 544        noblock = msg->msg_flags & MSG_DONTWAIT;
 545
 546        timeo = sock_sndtimeo(sk, noblock);
 547        timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 548                                1, timeo, &ret);
 549
 550        if (ret)
 551                goto err;
 552        ret = -EPIPE;
 553        if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 554                sock_flag(sk, SOCK_DEAD) ||
 555                (sk->sk_shutdown & RCV_SHUTDOWN))
 556                goto err;
 557
 558        /* Error if trying to write more than maximum frame size. */
 559        ret = -EMSGSIZE;
 560        if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 561                goto err;
 562
 563        buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 564
 565        ret = -ENOMEM;
 566        skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 567
 568        if (!skb || skb_tailroom(skb) < buffer_size)
 569                goto err;
 570
 571        skb_reserve(skb, cf_sk->headroom);
 572
 573        ret = memcpy_from_msg(skb_put(skb, len), msg, len);
 574
 575        if (ret)
 576                goto err;
 577        ret = transmit_skb(skb, cf_sk, noblock, timeo);
 578        if (ret < 0)
 579                /* skb is already freed */
 580                return ret;
 581
 582        return len;
 583err:
 584        kfree_skb(skb);
 585        return ret;
 586}
 587
 588/*
 589 * Copied from unix_stream_sendmsg and adapted to CAIF:
 590 * Changed removed permission handling and added waiting for flow on
 591 * and other minor adaptations.
 592 */
 593static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 594                               size_t len)
 595{
 596        struct sock *sk = sock->sk;
 597        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 598        int err, size;
 599        struct sk_buff *skb;
 600        int sent = 0;
 601        long timeo;
 602
 603        err = -EOPNOTSUPP;
 604        if (unlikely(msg->msg_flags&MSG_OOB))
 605                goto out_err;
 606
 607        if (unlikely(msg->msg_namelen))
 608                goto out_err;
 609
 610        timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 611        timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 612
 613        if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 614                goto pipe_err;
 615
 616        while (sent < len) {
 617
 618                size = len-sent;
 619
 620                if (size > cf_sk->maxframe)
 621                        size = cf_sk->maxframe;
 622
 623                /* If size is more than half of sndbuf, chop up message */
 624                if (size > ((sk->sk_sndbuf >> 1) - 64))
 625                        size = (sk->sk_sndbuf >> 1) - 64;
 626
 627                if (size > SKB_MAX_ALLOC)
 628                        size = SKB_MAX_ALLOC;
 629
 630                skb = sock_alloc_send_skb(sk,
 631                                        size + cf_sk->headroom +
 632                                        cf_sk->tailroom,
 633                                        msg->msg_flags&MSG_DONTWAIT,
 634                                        &err);
 635                if (skb == NULL)
 636                        goto out_err;
 637
 638                skb_reserve(skb, cf_sk->headroom);
 639                /*
 640                 *      If you pass two values to the sock_alloc_send_skb
 641                 *      it tries to grab the large buffer with GFP_NOFS
 642                 *      (which can fail easily), and if it fails grab the
 643                 *      fallback size buffer which is under a page and will
 644                 *      succeed. [Alan]
 645                 */
 646                size = min_t(int, size, skb_tailroom(skb));
 647
 648                err = memcpy_from_msg(skb_put(skb, size), msg, size);
 649                if (err) {
 650                        kfree_skb(skb);
 651                        goto out_err;
 652                }
 653                err = transmit_skb(skb, cf_sk,
 654                                msg->msg_flags&MSG_DONTWAIT, timeo);
 655                if (err < 0)
 656                        /* skb is already freed */
 657                        goto pipe_err;
 658
 659                sent += size;
 660        }
 661
 662        return sent;
 663
 664pipe_err:
 665        if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 666                send_sig(SIGPIPE, current, 0);
 667        err = -EPIPE;
 668out_err:
 669        return sent ? : err;
 670}
 671
 672static int setsockopt(struct socket *sock,
 673                      int lvl, int opt, char __user *ov, unsigned int ol)
 674{
 675        struct sock *sk = sock->sk;
 676        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 677        int linksel;
 678
 679        if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 680                return -ENOPROTOOPT;
 681
 682        switch (opt) {
 683        case CAIFSO_LINK_SELECT:
 684                if (ol < sizeof(int))
 685                        return -EINVAL;
 686                if (lvl != SOL_CAIF)
 687                        goto bad_sol;
 688                if (copy_from_user(&linksel, ov, sizeof(int)))
 689                        return -EINVAL;
 690                lock_sock(&(cf_sk->sk));
 691                cf_sk->conn_req.link_selector = linksel;
 692                release_sock(&cf_sk->sk);
 693                return 0;
 694
 695        case CAIFSO_REQ_PARAM:
 696                if (lvl != SOL_CAIF)
 697                        goto bad_sol;
 698                if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 699                        return -ENOPROTOOPT;
 700                lock_sock(&(cf_sk->sk));
 701                if (ol > sizeof(cf_sk->conn_req.param.data) ||
 702                        copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 703                        release_sock(&cf_sk->sk);
 704                        return -EINVAL;
 705                }
 706                cf_sk->conn_req.param.size = ol;
 707                release_sock(&cf_sk->sk);
 708                return 0;
 709
 710        default:
 711                return -ENOPROTOOPT;
 712        }
 713
 714        return 0;
 715bad_sol:
 716        return -ENOPROTOOPT;
 717
 718}
 719
 720/*
 721 * caif_connect() - Connect a CAIF Socket
 722 * Copied and modified af_irda.c:irda_connect().
 723 *
 724 * Note : by consulting "errno", the user space caller may learn the cause
 725 * of the failure. Most of them are visible in the function, others may come
 726 * from subroutines called and are listed here :
 727 *  o -EAFNOSUPPORT: bad socket family or type.
 728 *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 729 *  o -EINVAL: bad socket address, or CAIF link type
 730 *  o -ECONNREFUSED: remote end refused the connection.
 731 *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 732 *  o -EISCONN: already connected.
 733 *  o -ETIMEDOUT: Connection timed out (send timeout)
 734 *  o -ENODEV: No link layer to send request
 735 *  o -ECONNRESET: Received Shutdown indication or lost link layer
 736 *  o -ENOMEM: Out of memory
 737 *
 738 *  State Strategy:
 739 *  o sk_state: holds the CAIF_* protocol state, it's updated by
 740 *      caif_ctrl_cb.
 741 *  o sock->state: holds the SS_* socket state and is updated by connect and
 742 *      disconnect.
 743 */
 744static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 745                        int addr_len, int flags)
 746{
 747        struct sock *sk = sock->sk;
 748        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 749        long timeo;
 750        int err;
 751        int ifindex, headroom, tailroom;
 752        unsigned int mtu;
 753        struct net_device *dev;
 754
 755        lock_sock(sk);
 756
 757        err = -EINVAL;
 758        if (addr_len < offsetofend(struct sockaddr, sa_family))
 759                goto out;
 760
 761        err = -EAFNOSUPPORT;
 762        if (uaddr->sa_family != AF_CAIF)
 763                goto out;
 764
 765        switch (sock->state) {
 766        case SS_UNCONNECTED:
 767                /* Normal case, a fresh connect */
 768                caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 769                break;
 770        case SS_CONNECTING:
 771                switch (sk->sk_state) {
 772                case CAIF_CONNECTED:
 773                        sock->state = SS_CONNECTED;
 774                        err = -EISCONN;
 775                        goto out;
 776                case CAIF_DISCONNECTED:
 777                        /* Reconnect allowed */
 778                        break;
 779                case CAIF_CONNECTING:
 780                        err = -EALREADY;
 781                        if (flags & O_NONBLOCK)
 782                                goto out;
 783                        goto wait_connect;
 784                }
 785                break;
 786        case SS_CONNECTED:
 787                caif_assert(sk->sk_state == CAIF_CONNECTED ||
 788                                sk->sk_state == CAIF_DISCONNECTED);
 789                if (sk->sk_shutdown & SHUTDOWN_MASK) {
 790                        /* Allow re-connect after SHUTDOWN_IND */
 791                        caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 792                        caif_free_client(&cf_sk->layer);
 793                        break;
 794                }
 795                /* No reconnect on a seqpacket socket */
 796                err = -EISCONN;
 797                goto out;
 798        case SS_DISCONNECTING:
 799        case SS_FREE:
 800                caif_assert(1); /*Should never happen */
 801                break;
 802        }
 803        sk->sk_state = CAIF_DISCONNECTED;
 804        sock->state = SS_UNCONNECTED;
 805        sk_stream_kill_queues(&cf_sk->sk);
 806
 807        err = -EINVAL;
 808        if (addr_len != sizeof(struct sockaddr_caif))
 809                goto out;
 810
 811        memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 812                sizeof(struct sockaddr_caif));
 813
 814        /* Move to connecting socket, start sending Connect Requests */
 815        sock->state = SS_CONNECTING;
 816        sk->sk_state = CAIF_CONNECTING;
 817
 818        /* Check priority value comming from socket */
 819        /* if priority value is out of range it will be ajusted */
 820        if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 821                cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 822        else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 823                cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 824        else
 825                cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 826
 827        /*ifindex = id of the interface.*/
 828        cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 829
 830        cf_sk->layer.receive = caif_sktrecv_cb;
 831
 832        err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 833                                &cf_sk->layer, &ifindex, &headroom, &tailroom);
 834
 835        if (err < 0) {
 836                cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 837                cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 838                goto out;
 839        }
 840
 841        err = -ENODEV;
 842        rcu_read_lock();
 843        dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 844        if (!dev) {
 845                rcu_read_unlock();
 846                goto out;
 847        }
 848        cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 849        mtu = dev->mtu;
 850        rcu_read_unlock();
 851
 852        cf_sk->tailroom = tailroom;
 853        cf_sk->maxframe = mtu - (headroom + tailroom);
 854        if (cf_sk->maxframe < 1) {
 855                pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 856                err = -ENODEV;
 857                goto out;
 858        }
 859
 860        err = -EINPROGRESS;
 861wait_connect:
 862
 863        if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 864                goto out;
 865
 866        timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 867
 868        release_sock(sk);
 869        err = -ERESTARTSYS;
 870        timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 871                        sk->sk_state != CAIF_CONNECTING,
 872                        timeo);
 873        lock_sock(sk);
 874        if (timeo < 0)
 875                goto out; /* -ERESTARTSYS */
 876
 877        err = -ETIMEDOUT;
 878        if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 879                goto out;
 880        if (sk->sk_state != CAIF_CONNECTED) {
 881                sock->state = SS_UNCONNECTED;
 882                err = sock_error(sk);
 883                if (!err)
 884                        err = -ECONNREFUSED;
 885                goto out;
 886        }
 887        sock->state = SS_CONNECTED;
 888        err = 0;
 889out:
 890        release_sock(sk);
 891        return err;
 892}
 893
 894/*
 895 * caif_release() - Disconnect a CAIF Socket
 896 * Copied and modified af_irda.c:irda_release().
 897 */
 898static int caif_release(struct socket *sock)
 899{
 900        struct sock *sk = sock->sk;
 901        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 902
 903        if (!sk)
 904                return 0;
 905
 906        set_tx_flow_off(cf_sk);
 907
 908        /*
 909         * Ensure that packets are not queued after this point in time.
 910         * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 911         * this ensures no packets when sock is dead.
 912         */
 913        spin_lock_bh(&sk->sk_receive_queue.lock);
 914        sock_set_flag(sk, SOCK_DEAD);
 915        spin_unlock_bh(&sk->sk_receive_queue.lock);
 916        sock->sk = NULL;
 917
 918        WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 919        debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 920
 921        lock_sock(&(cf_sk->sk));
 922        sk->sk_state = CAIF_DISCONNECTED;
 923        sk->sk_shutdown = SHUTDOWN_MASK;
 924
 925        caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 926        cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 927        wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
 928
 929        sock_orphan(sk);
 930        sk_stream_kill_queues(&cf_sk->sk);
 931        release_sock(sk);
 932        sock_put(sk);
 933        return 0;
 934}
 935
 936/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 937static __poll_t caif_poll(struct file *file,
 938                              struct socket *sock, poll_table *wait)
 939{
 940        struct sock *sk = sock->sk;
 941        __poll_t mask;
 942        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 943
 944        sock_poll_wait(file, sock, wait);
 945        mask = 0;
 946
 947        /* exceptional events? */
 948        if (sk->sk_err)
 949                mask |= EPOLLERR;
 950        if (sk->sk_shutdown == SHUTDOWN_MASK)
 951                mask |= EPOLLHUP;
 952        if (sk->sk_shutdown & RCV_SHUTDOWN)
 953                mask |= EPOLLRDHUP;
 954
 955        /* readable? */
 956        if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
 957                (sk->sk_shutdown & RCV_SHUTDOWN))
 958                mask |= EPOLLIN | EPOLLRDNORM;
 959
 960        /*
 961         * we set writable also when the other side has shut down the
 962         * connection. This prevents stuck sockets.
 963         */
 964        if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 965                mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
 966
 967        return mask;
 968}
 969
 970static const struct proto_ops caif_seqpacket_ops = {
 971        .family = PF_CAIF,
 972        .owner = THIS_MODULE,
 973        .release = caif_release,
 974        .bind = sock_no_bind,
 975        .connect = caif_connect,
 976        .socketpair = sock_no_socketpair,
 977        .accept = sock_no_accept,
 978        .getname = sock_no_getname,
 979        .poll = caif_poll,
 980        .ioctl = sock_no_ioctl,
 981        .listen = sock_no_listen,
 982        .shutdown = sock_no_shutdown,
 983        .setsockopt = setsockopt,
 984        .getsockopt = sock_no_getsockopt,
 985        .sendmsg = caif_seqpkt_sendmsg,
 986        .recvmsg = caif_seqpkt_recvmsg,
 987        .mmap = sock_no_mmap,
 988        .sendpage = sock_no_sendpage,
 989};
 990
 991static const struct proto_ops caif_stream_ops = {
 992        .family = PF_CAIF,
 993        .owner = THIS_MODULE,
 994        .release = caif_release,
 995        .bind = sock_no_bind,
 996        .connect = caif_connect,
 997        .socketpair = sock_no_socketpair,
 998        .accept = sock_no_accept,
 999        .getname = sock_no_getname,
1000        .poll = caif_poll,
1001        .ioctl = sock_no_ioctl,
1002        .listen = sock_no_listen,
1003        .shutdown = sock_no_shutdown,
1004        .setsockopt = setsockopt,
1005        .getsockopt = sock_no_getsockopt,
1006        .sendmsg = caif_stream_sendmsg,
1007        .recvmsg = caif_stream_recvmsg,
1008        .mmap = sock_no_mmap,
1009        .sendpage = sock_no_sendpage,
1010};
1011
1012/* This function is called when a socket is finally destroyed. */
1013static void caif_sock_destructor(struct sock *sk)
1014{
1015        struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1016        caif_assert(!refcount_read(&sk->sk_wmem_alloc));
1017        caif_assert(sk_unhashed(sk));
1018        caif_assert(!sk->sk_socket);
1019        if (!sock_flag(sk, SOCK_DEAD)) {
1020                pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1021                return;
1022        }
1023        sk_stream_kill_queues(&cf_sk->sk);
1024        caif_free_client(&cf_sk->layer);
1025}
1026
1027static int caif_create(struct net *net, struct socket *sock, int protocol,
1028                       int kern)
1029{
1030        struct sock *sk = NULL;
1031        struct caifsock *cf_sk = NULL;
1032        static struct proto prot = {.name = "PF_CAIF",
1033                .owner = THIS_MODULE,
1034                .obj_size = sizeof(struct caifsock),
1035                .useroffset = offsetof(struct caifsock, conn_req.param),
1036                .usersize = sizeof_field(struct caifsock, conn_req.param)
1037        };
1038
1039        if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1040                return -EPERM;
1041        /*
1042         * The sock->type specifies the socket type to use.
1043         * The CAIF socket is a packet stream in the sense
1044         * that it is packet based. CAIF trusts the reliability
1045         * of the link, no resending is implemented.
1046         */
1047        if (sock->type == SOCK_SEQPACKET)
1048                sock->ops = &caif_seqpacket_ops;
1049        else if (sock->type == SOCK_STREAM)
1050                sock->ops = &caif_stream_ops;
1051        else
1052                return -ESOCKTNOSUPPORT;
1053
1054        if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1055                return -EPROTONOSUPPORT;
1056        /*
1057         * Set the socket state to unconnected.  The socket state
1058         * is really not used at all in the net/core or socket.c but the
1059         * initialization makes sure that sock->state is not uninitialized.
1060         */
1061        sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1062        if (!sk)
1063                return -ENOMEM;
1064
1065        cf_sk = container_of(sk, struct caifsock, sk);
1066
1067        /* Store the protocol */
1068        sk->sk_protocol = (unsigned char) protocol;
1069
1070        /* Initialize default priority for well-known cases */
1071        switch (protocol) {
1072        case CAIFPROTO_AT:
1073                sk->sk_priority = TC_PRIO_CONTROL;
1074                break;
1075        case CAIFPROTO_RFM:
1076                sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1077                break;
1078        default:
1079                sk->sk_priority = TC_PRIO_BESTEFFORT;
1080        }
1081
1082        /*
1083         * Lock in order to try to stop someone from opening the socket
1084         * too early.
1085         */
1086        lock_sock(&(cf_sk->sk));
1087
1088        /* Initialize the nozero default sock structure data. */
1089        sock_init_data(sock, sk);
1090        sk->sk_destruct = caif_sock_destructor;
1091
1092        mutex_init(&cf_sk->readlock); /* single task reading lock */
1093        cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1094        cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1095        cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1096
1097        set_tx_flow_off(cf_sk);
1098        set_rx_flow_on(cf_sk);
1099
1100        /* Set default options on configuration */
1101        cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1102        cf_sk->conn_req.protocol = protocol;
1103        release_sock(&cf_sk->sk);
1104        return 0;
1105}
1106
1107
1108static const struct net_proto_family caif_family_ops = {
1109        .family = PF_CAIF,
1110        .create = caif_create,
1111        .owner = THIS_MODULE,
1112};
1113
1114static int __init caif_sktinit_module(void)
1115{
1116        return sock_register(&caif_family_ops);
1117}
1118
1119static void __exit caif_sktexit_module(void)
1120{
1121        sock_unregister(PF_CAIF);
1122}
1123module_init(caif_sktinit_module);
1124module_exit(caif_sktexit_module);
1125