af_nfc.c

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/*
 * Copyright (C) 2011 Instituto Nokia de Tecnologia
 *
 * Authors:
 *    Aloisio Almeida Jr <[email protected]>
 *    Lauro Ramos Venancio <[email protected]>
 *
 * 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.
 */

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

#include "nfc.h"

static DEFINE_RWLOCK(proto_tab_lock);
static const struct nfc_protocol *proto_tab[NFC_SOCKPROTO_MAX];

static int nfc_sock_create(struct net *net, struct socket *sock, int proto,
               int kern)
{
    int rc = -EPROTONOSUPPORT;

    if (net != &init_net)
        return -EAFNOSUPPORT;

    if (proto < 0 || proto >= NFC_SOCKPROTO_MAX)
        return -EINVAL;

    read_lock(&proto_tab_lock);
    if (proto_tab[proto] && try_module_get(proto_tab[proto]->owner)) {
        rc = proto_tab[proto]->create(net, sock, proto_tab[proto]);
        module_put(proto_tab[proto]->owner);
    }
    read_unlock(&proto_tab_lock);

    return rc;
}

static struct net_proto_family nfc_sock_family_ops = {
    .owner  = THIS_MODULE,
    .family = PF_NFC,
    .create = nfc_sock_create,
};

int nfc_proto_register(const struct nfc_protocol *nfc_proto)
{
    int rc;

    if (nfc_proto->id < 0 || nfc_proto->id >= NFC_SOCKPROTO_MAX)
        return -EINVAL;

    rc = proto_register(nfc_proto->proto, 0);
    if (rc)
        return rc;

    write_lock(&proto_tab_lock);
    if (proto_tab[nfc_proto->id])
        rc = -EBUSY;
    else
        proto_tab[nfc_proto->id] = nfc_proto;
    write_unlock(&proto_tab_lock);

    return rc;
}
EXPORT_SYMBOL(nfc_proto_register);

void nfc_proto_unregister(const struct nfc_protocol *nfc_proto)
{
    write_lock(&proto_tab_lock);
    proto_tab[nfc_proto->id] = NULL;
    write_unlock(&proto_tab_lock);

    proto_unregister(nfc_proto->proto);
}
EXPORT_SYMBOL(nfc_proto_unregister);

int __init af_nfc_init(void)
{
    return sock_register(&nfc_sock_family_ops);
}

void af_nfc_exit(void)
{
    sock_unregister(PF_NFC);
}