sock.c

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/*
 * Copyright (C) 2011  Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#define pr_fmt(fmt) "llcp: %s: " fmt, __func__

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nfc.h>

#include "../nfc.h"
#include "llcp.h"

static int sock_wait_state(struct sock *sk, int state, unsigned long timeo)
{
    DECLARE_WAITQUEUE(wait, current);
    int err = 0;

    pr_debug("sk %p", sk);

    add_wait_queue(sk_sleep(sk), &wait);
    set_current_state(TASK_INTERRUPTIBLE);

    while (sk->sk_state != state) {
        if (!timeo) {
            err = -EINPROGRESS;
            break;
        }

        if (signal_pending(current)) {
            err = sock_intr_errno(timeo);
            break;
        }

        release_sock(sk);
        timeo = schedule_timeout(timeo);
        lock_sock(sk);
        set_current_state(TASK_INTERRUPTIBLE);

        err = sock_error(sk);
        if (err)
            break;
    }

    __set_current_state(TASK_RUNNING);
    remove_wait_queue(sk_sleep(sk), &wait);
    return err;
}

static struct proto llcp_sock_proto = {
    .name     = "NFC_LLCP",
    .owner    = THIS_MODULE,
    .obj_size = sizeof(struct nfc_llcp_sock),
};

static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    struct nfc_llcp_local *local;
    struct nfc_dev *dev;
    struct sockaddr_nfc_llcp llcp_addr;
    int len, ret = 0;

    if (!addr || addr->sa_family != AF_NFC)
        return -EINVAL;

    pr_debug("sk %p addr %p family %d\n", sk, addr, addr->sa_family);

    memset(&llcp_addr, 0, sizeof(llcp_addr));
    len = min_t(unsigned int, sizeof(llcp_addr), alen);
    memcpy(&llcp_addr, addr, len);

    /* This is going to be a listening socket, dsap must be 0 */
    if (llcp_addr.dsap != 0)
        return -EINVAL;

    lock_sock(sk);

    if (sk->sk_state != LLCP_CLOSED) {
        ret = -EBADFD;
        goto error;
    }

    dev = nfc_get_device(llcp_addr.dev_idx);
    if (dev == NULL) {
        ret = -ENODEV;
        goto error;
    }

    local = nfc_llcp_find_local(dev);
    if (local == NULL) {
        ret = -ENODEV;
        goto put_dev;
    }

    llcp_sock->dev = dev;
    llcp_sock->local = nfc_llcp_local_get(local);
    llcp_sock->nfc_protocol = llcp_addr.nfc_protocol;
    llcp_sock->service_name_len = min_t(unsigned int,
                        llcp_addr.service_name_len,
                        NFC_LLCP_MAX_SERVICE_NAME);
    llcp_sock->service_name = kmemdup(llcp_addr.service_name,
                      llcp_sock->service_name_len,
                      GFP_KERNEL);

    llcp_sock->ssap = nfc_llcp_get_sdp_ssap(local, llcp_sock);
    if (llcp_sock->ssap == LLCP_SAP_MAX) {
        ret = -EADDRINUSE;
        goto put_dev;
    }

    llcp_sock->reserved_ssap = llcp_sock->ssap;

    nfc_llcp_sock_link(&local->sockets, sk);

    pr_debug("Socket bound to SAP %d\n", llcp_sock->ssap);

    sk->sk_state = LLCP_BOUND;

put_dev:
    nfc_put_device(dev);

error:
    release_sock(sk);
    return ret;
}

static int llcp_raw_sock_bind(struct socket *sock, struct sockaddr *addr,
                  int alen)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    struct nfc_llcp_local *local;
    struct nfc_dev *dev;
    struct sockaddr_nfc_llcp llcp_addr;
    int len, ret = 0;

    if (!addr || addr->sa_family != AF_NFC)
        return -EINVAL;

    pr_debug("sk %p addr %p family %d\n", sk, addr, addr->sa_family);

    memset(&llcp_addr, 0, sizeof(llcp_addr));
    len = min_t(unsigned int, sizeof(llcp_addr), alen);
    memcpy(&llcp_addr, addr, len);

    lock_sock(sk);

    if (sk->sk_state != LLCP_CLOSED) {
        ret = -EBADFD;
        goto error;
    }

    dev = nfc_get_device(llcp_addr.dev_idx);
    if (dev == NULL) {
        ret = -ENODEV;
        goto error;
    }

    local = nfc_llcp_find_local(dev);
    if (local == NULL) {
        ret = -ENODEV;
        goto put_dev;
    }

    llcp_sock->dev = dev;
    llcp_sock->local = nfc_llcp_local_get(local);
    llcp_sock->nfc_protocol = llcp_addr.nfc_protocol;

    nfc_llcp_sock_link(&local->raw_sockets, sk);

    sk->sk_state = LLCP_BOUND;

put_dev:
    nfc_put_device(dev);

error:
    release_sock(sk);
    return ret;
}

static int llcp_sock_listen(struct socket *sock, int backlog)
{
    struct sock *sk = sock->sk;
    int ret = 0;

    pr_debug("sk %p backlog %d\n", sk, backlog);

    lock_sock(sk);

    if ((sock->type != SOCK_SEQPACKET && sock->type != SOCK_STREAM)
        || sk->sk_state != LLCP_BOUND) {
        ret = -EBADFD;
        goto error;
    }

    sk->sk_max_ack_backlog = backlog;
    sk->sk_ack_backlog = 0;

    pr_debug("Socket listening\n");
    sk->sk_state = LLCP_LISTEN;

error:
    release_sock(sk);

    return ret;
}

void nfc_llcp_accept_unlink(struct sock *sk)
{
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);

    pr_debug("state %d\n", sk->sk_state);

    list_del_init(&llcp_sock->accept_queue);
    sk_acceptq_removed(llcp_sock->parent);
    llcp_sock->parent = NULL;

    sock_put(sk);
}

void nfc_llcp_accept_enqueue(struct sock *parent, struct sock *sk)
{
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    struct nfc_llcp_sock *llcp_sock_parent = nfc_llcp_sock(parent);

    /* Lock will be free from unlink */
    sock_hold(sk);

    list_add_tail(&llcp_sock->accept_queue,
              &llcp_sock_parent->accept_queue);
    llcp_sock->parent = parent;
    sk_acceptq_added(parent);
}

struct sock *nfc_llcp_accept_dequeue(struct sock *parent,
                     struct socket *newsock)
{
    struct nfc_llcp_sock *lsk, *n, *llcp_parent;
    struct sock *sk;

    llcp_parent = nfc_llcp_sock(parent);

    list_for_each_entry_safe(lsk, n, &llcp_parent->accept_queue,
                 accept_queue) {
        sk = &lsk->sk;
        lock_sock(sk);

        if (sk->sk_state == LLCP_CLOSED) {
            release_sock(sk);
            nfc_llcp_accept_unlink(sk);
            continue;
        }

        if (sk->sk_state == LLCP_CONNECTED || !newsock) {
            nfc_llcp_accept_unlink(sk);
            if (newsock)
                sock_graft(sk, newsock);

            release_sock(sk);

            pr_debug("Returning sk state %d\n", sk->sk_state);

            return sk;
        }

        release_sock(sk);
    }

    return NULL;
}

static int llcp_sock_accept(struct socket *sock, struct socket *newsock,
                int flags)
{
    DECLARE_WAITQUEUE(wait, current);
    struct sock *sk = sock->sk, *new_sk;
    long timeo;
    int ret = 0;

    pr_debug("parent %p\n", sk);

    lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

    if (sk->sk_state != LLCP_LISTEN) {
        ret = -EBADFD;
        goto error;
    }

    timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

    /* Wait for an incoming connection. */
    add_wait_queue_exclusive(sk_sleep(sk), &wait);
    while (!(new_sk = nfc_llcp_accept_dequeue(sk, newsock))) {
        set_current_state(TASK_INTERRUPTIBLE);

        if (!timeo) {
            ret = -EAGAIN;
            break;
        }

        if (signal_pending(current)) {
            ret = sock_intr_errno(timeo);
            break;
        }

        release_sock(sk);
        timeo = schedule_timeout(timeo);
        lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
    }
    __set_current_state(TASK_RUNNING);
    remove_wait_queue(sk_sleep(sk), &wait);

    if (ret)
        goto error;

    newsock->state = SS_CONNECTED;

    pr_debug("new socket %p\n", new_sk);

error:
    release_sock(sk);

    return ret;
}

static int llcp_sock_getname(struct socket *sock, struct sockaddr *uaddr,
                 int *len, int peer)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, llcp_addr, uaddr);

    if (llcp_sock == NULL || llcp_sock->dev == NULL)
        return -EBADFD;

    pr_debug("%p %d %d %d\n", sk, llcp_sock->target_idx,
         llcp_sock->dsap, llcp_sock->ssap);

    uaddr->sa_family = AF_NFC;

    *len = sizeof(struct sockaddr_nfc_llcp);

    llcp_addr->dev_idx = llcp_sock->dev->idx;
    llcp_addr->target_idx = llcp_sock->target_idx;
    llcp_addr->dsap = llcp_sock->dsap;
    llcp_addr->ssap = llcp_sock->ssap;
    llcp_addr->service_name_len = llcp_sock->service_name_len;
    memcpy(llcp_addr->service_name, llcp_sock->service_name,
           llcp_addr->service_name_len);

    return 0;
}

static inline unsigned int llcp_accept_poll(struct sock *parent)
{
    struct nfc_llcp_sock *llcp_sock, *n, *parent_sock;
    struct sock *sk;

    parent_sock = nfc_llcp_sock(parent);

    list_for_each_entry_safe(llcp_sock, n, &parent_sock->accept_queue,
                 accept_queue) {
        sk = &llcp_sock->sk;

        if (sk->sk_state == LLCP_CONNECTED)
            return POLLIN | POLLRDNORM;
    }

    return 0;
}

static unsigned int llcp_sock_poll(struct file *file, struct socket *sock,
                   poll_table *wait)
{
    struct sock *sk = sock->sk;
    unsigned int mask = 0;

    pr_debug("%p\n", sk);

    sock_poll_wait(file, sk_sleep(sk), wait);

    if (sk->sk_state == LLCP_LISTEN)
        return llcp_accept_poll(sk);

    if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
        mask |= POLLERR;

    if (!skb_queue_empty(&sk->sk_receive_queue))
        mask |= POLLIN | POLLRDNORM;

    if (sk->sk_state == LLCP_CLOSED)
        mask |= POLLHUP;

    if (sk->sk_shutdown & RCV_SHUTDOWN)
        mask |= POLLRDHUP | POLLIN | POLLRDNORM;

    if (sk->sk_shutdown == SHUTDOWN_MASK)
        mask |= POLLHUP;

    if (sock_writeable(sk))
        mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
    else
        set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

    pr_debug("mask 0x%x\n", mask);

    return mask;
}

static int llcp_sock_release(struct socket *sock)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_local *local;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    int err = 0;

    if (!sk)
        return 0;

    pr_debug("%p\n", sk);

    local = llcp_sock->local;
    if (local == NULL) {
        err = -ENODEV;
        goto out;
    }

    lock_sock(sk);

    /* Send a DISC */
    if (sk->sk_state == LLCP_CONNECTED)
        nfc_llcp_disconnect(llcp_sock);

    if (sk->sk_state == LLCP_LISTEN) {
        struct nfc_llcp_sock *lsk, *n;
        struct sock *accept_sk;

        list_for_each_entry_safe(lsk, n, &llcp_sock->accept_queue,
                     accept_queue) {
            accept_sk = &lsk->sk;
            lock_sock(accept_sk);

            nfc_llcp_disconnect(lsk);
            nfc_llcp_accept_unlink(accept_sk);

            release_sock(accept_sk);

            sock_orphan(accept_sk);
        }
    }

    if (llcp_sock->reserved_ssap < LLCP_SAP_MAX)
        nfc_llcp_put_ssap(llcp_sock->local, llcp_sock->ssap);

    release_sock(sk);

    if (sock->type == SOCK_RAW)
        nfc_llcp_sock_unlink(&local->raw_sockets, sk);
    else
        nfc_llcp_sock_unlink(&local->sockets, sk);

out:
    sock_orphan(sk);
    sock_put(sk);

    return err;
}

static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
                 int len, int flags)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    struct sockaddr_nfc_llcp *addr = (struct sockaddr_nfc_llcp *)_addr;
    struct nfc_dev *dev;
    struct nfc_llcp_local *local;
    int ret = 0;

    pr_debug("sock %p sk %p flags 0x%x\n", sock, sk, flags);

    if (!addr || len < sizeof(struct sockaddr_nfc) ||
        addr->sa_family != AF_NFC)
        return -EINVAL;

    if (addr->service_name_len == 0 && addr->dsap == 0)
        return -EINVAL;

    pr_debug("addr dev_idx=%u target_idx=%u protocol=%u\n", addr->dev_idx,
         addr->target_idx, addr->nfc_protocol);

    lock_sock(sk);

    if (sk->sk_state == LLCP_CONNECTED) {
        ret = -EISCONN;
        goto error;
    }

    dev = nfc_get_device(addr->dev_idx);
    if (dev == NULL) {
        ret = -ENODEV;
        goto error;
    }

    local = nfc_llcp_find_local(dev);
    if (local == NULL) {
        ret = -ENODEV;
        goto put_dev;
    }

    device_lock(&dev->dev);
    if (dev->dep_link_up == false) {
        ret = -ENOLINK;
        device_unlock(&dev->dev);
        goto put_dev;
    }
    device_unlock(&dev->dev);

    if (local->rf_mode == NFC_RF_INITIATOR &&
        addr->target_idx != local->target_idx) {
        ret = -ENOLINK;
        goto put_dev;
    }

    llcp_sock->dev = dev;
    llcp_sock->local = nfc_llcp_local_get(local);
    llcp_sock->miu = llcp_sock->local->remote_miu;
    llcp_sock->ssap = nfc_llcp_get_local_ssap(local);
    if (llcp_sock->ssap == LLCP_SAP_MAX) {
        ret = -ENOMEM;
        goto put_dev;
    }

    llcp_sock->reserved_ssap = llcp_sock->ssap;

    if (addr->service_name_len == 0)
        llcp_sock->dsap = addr->dsap;
    else
        llcp_sock->dsap = LLCP_SAP_SDP;
    llcp_sock->nfc_protocol = addr->nfc_protocol;
    llcp_sock->service_name_len = min_t(unsigned int,
                        addr->service_name_len,
                        NFC_LLCP_MAX_SERVICE_NAME);
    llcp_sock->service_name = kmemdup(addr->service_name,
                      llcp_sock->service_name_len,
                      GFP_KERNEL);

    nfc_llcp_sock_link(&local->connecting_sockets, sk);

    ret = nfc_llcp_send_connect(llcp_sock);
    if (ret)
        goto sock_unlink;

    ret = sock_wait_state(sk, LLCP_CONNECTED,
                  sock_sndtimeo(sk, flags & O_NONBLOCK));
    if (ret)
        goto sock_unlink;

    release_sock(sk);

    return 0;

sock_unlink:
    nfc_llcp_put_ssap(local, llcp_sock->ssap);

    nfc_llcp_sock_unlink(&local->connecting_sockets, sk);

put_dev:
    nfc_put_device(dev);

error:
    release_sock(sk);
    return ret;
}

static int llcp_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
                 struct msghdr *msg, size_t len)
{
    struct sock *sk = sock->sk;
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
    int ret;

    pr_debug("sock %p sk %p", sock, sk);

    ret = sock_error(sk);
    if (ret)
        return ret;

    if (msg->msg_flags & MSG_OOB)
        return -EOPNOTSUPP;

    lock_sock(sk);

    if (sk->sk_state != LLCP_CONNECTED) {
        release_sock(sk);
        return -ENOTCONN;
    }

    release_sock(sk);

    return nfc_llcp_send_i_frame(llcp_sock, msg, len);
}

static int llcp_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
                 struct msghdr *msg, size_t len, int flags)
{
    int noblock = flags & MSG_DONTWAIT;
    struct sock *sk = sock->sk;
    unsigned int copied, rlen;
    struct sk_buff *skb, *cskb;
    int err = 0;

    pr_debug("%p %zu\n", sk, len);

    lock_sock(sk);

    if (sk->sk_state == LLCP_CLOSED &&
        skb_queue_empty(&sk->sk_receive_queue)) {
        release_sock(sk);
        return 0;
    }

    release_sock(sk);

    if (flags & (MSG_OOB))
        return -EOPNOTSUPP;

    skb = skb_recv_datagram(sk, flags, noblock, &err);
    if (!skb) {
        pr_err("Recv datagram failed state %d %d %d",
               sk->sk_state, err, sock_error(sk));

        if (sk->sk_shutdown & RCV_SHUTDOWN)
            return 0;

        return err;
    }

    rlen = skb->len;        /* real length of skb */
    copied = min_t(unsigned int, rlen, len);

    cskb = skb;
    if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
        if (!(flags & MSG_PEEK))
            skb_queue_head(&sk->sk_receive_queue, skb);
        return -EFAULT;
    }

    /* Mark read part of skb as used */
    if (!(flags & MSG_PEEK)) {

        /* SOCK_STREAM: re-queue skb if it contains unreceived data */
        if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_RAW) {
            skb_pull(skb, copied);
            if (skb->len) {
                skb_queue_head(&sk->sk_receive_queue, skb);
                goto done;
            }
        }

        kfree_skb(skb);
    }

    /* XXX Queue backlogged skbs */

done:
    /* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
    if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
        copied = rlen;

    return copied;
}

static const struct proto_ops llcp_sock_ops = {
    .family         = PF_NFC,
    .owner          = THIS_MODULE,
    .bind           = llcp_sock_bind,
    .connect        = llcp_sock_connect,
    .release        = llcp_sock_release,
    .socketpair     = sock_no_socketpair,
    .accept         = llcp_sock_accept,
    .getname        = llcp_sock_getname,
    .poll           = llcp_sock_poll,
    .ioctl          = sock_no_ioctl,
    .listen         = llcp_sock_listen,
    .shutdown       = sock_no_shutdown,
    .setsockopt     = sock_no_setsockopt,
    .getsockopt     = sock_no_getsockopt,
    .sendmsg        = llcp_sock_sendmsg,
    .recvmsg        = llcp_sock_recvmsg,
    .mmap           = sock_no_mmap,
};

static const struct proto_ops llcp_rawsock_ops = {
    .family         = PF_NFC,
    .owner          = THIS_MODULE,
    .bind           = llcp_raw_sock_bind,
    .connect        = sock_no_connect,
    .release        = llcp_sock_release,
    .socketpair     = sock_no_socketpair,
    .accept         = sock_no_accept,
    .getname        = llcp_sock_getname,
    .poll           = llcp_sock_poll,
    .ioctl          = sock_no_ioctl,
    .listen         = sock_no_listen,
    .shutdown       = sock_no_shutdown,
    .setsockopt     = sock_no_setsockopt,
    .getsockopt     = sock_no_getsockopt,
    .sendmsg        = sock_no_sendmsg,
    .recvmsg        = llcp_sock_recvmsg,
    .mmap           = sock_no_mmap,
};

static void llcp_sock_destruct(struct sock *sk)
{
    struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);

    pr_debug("%p\n", sk);

    if (sk->sk_state == LLCP_CONNECTED)
        nfc_put_device(llcp_sock->dev);

    skb_queue_purge(&sk->sk_receive_queue);

    nfc_llcp_sock_free(llcp_sock);

    if (!sock_flag(sk, SOCK_DEAD)) {
        pr_err("Freeing alive NFC LLCP socket %p\n", sk);
        return;
    }
}

struct sock *nfc_llcp_sock_alloc(struct socket *sock, int type, gfp_t gfp)
{
    struct sock *sk;
    struct nfc_llcp_sock *llcp_sock;

    sk = sk_alloc(&init_net, PF_NFC, gfp, &llcp_sock_proto);
    if (!sk)
        return NULL;

    llcp_sock = nfc_llcp_sock(sk);

    sock_init_data(sock, sk);
    sk->sk_state = LLCP_CLOSED;
    sk->sk_protocol = NFC_SOCKPROTO_LLCP;
    sk->sk_type = type;
    sk->sk_destruct = llcp_sock_destruct;

    llcp_sock->ssap = 0;
    llcp_sock->dsap = LLCP_SAP_SDP;
    llcp_sock->rw = LLCP_DEFAULT_RW;
    llcp_sock->miu = LLCP_DEFAULT_MIU;
    llcp_sock->send_n = llcp_sock->send_ack_n = 0;
    llcp_sock->recv_n = llcp_sock->recv_ack_n = 0;
    llcp_sock->remote_ready = 1;
    llcp_sock->reserved_ssap = LLCP_SAP_MAX;
    skb_queue_head_init(&llcp_sock->tx_queue);
    skb_queue_head_init(&llcp_sock->tx_pending_queue);
    skb_queue_head_init(&llcp_sock->tx_backlog_queue);
    INIT_LIST_HEAD(&llcp_sock->accept_queue);

    if (sock != NULL)
        sock->state = SS_UNCONNECTED;

    return sk;
}

void nfc_llcp_sock_free(struct nfc_llcp_sock *sock)
{
    kfree(sock->service_name);

    skb_queue_purge(&sock->tx_queue);
    skb_queue_purge(&sock->tx_pending_queue);
    skb_queue_purge(&sock->tx_backlog_queue);

    list_del_init(&sock->accept_queue);

    sock->parent = NULL;

    nfc_llcp_local_put(sock->local);
}

static int llcp_sock_create(struct net *net, struct socket *sock,
                const struct nfc_protocol *nfc_proto)
{
    struct sock *sk;

    pr_debug("%p\n", sock);

    if (sock->type != SOCK_STREAM &&
        sock->type != SOCK_DGRAM &&
        sock->type != SOCK_RAW)
        return -ESOCKTNOSUPPORT;

    if (sock->type == SOCK_RAW)
        sock->ops = &llcp_rawsock_ops;
    else
        sock->ops = &llcp_sock_ops;

    sk = nfc_llcp_sock_alloc(sock, sock->type, GFP_ATOMIC);
    if (sk == NULL)
        return -ENOMEM;

    return 0;
}

static const struct nfc_protocol llcp_nfc_proto = {
    .id   = NFC_SOCKPROTO_LLCP,
    .proto    = &llcp_sock_proto,
    .owner    = THIS_MODULE,
    .create   = llcp_sock_create
};

int __init nfc_llcp_sock_init(void)
{
    return nfc_proto_register(&llcp_nfc_proto);
}

void nfc_llcp_sock_exit(void)
{
    nfc_proto_unregister(&llcp_nfc_proto);
}