pppox.c

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#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/init.h>
#include <linux/if_pppox.h>
#include <linux/ppp_defs.h>
#include <linux/ppp-ioctl.h>
#include <linux/ppp_channel.h>
#include <linux/kmod.h>

#include <net/sock.h>

#include <asm/uaccess.h>

static const struct pppox_proto *pppox_protos[PX_MAX_PROTO + 1];

int register_pppox_proto(int proto_num, const struct pppox_proto *pp)
{
    if (proto_num < 0 || proto_num > PX_MAX_PROTO)
        return -EINVAL;
    if (pppox_protos[proto_num])
        return -EALREADY;
    pppox_protos[proto_num] = pp;
    return 0;
}

void unregister_pppox_proto(int proto_num)
{
    if (proto_num >= 0 && proto_num <= PX_MAX_PROTO)
        pppox_protos[proto_num] = NULL;
}

void pppox_unbind_sock(struct sock *sk)
{
    /* Clear connection to ppp device, if attached. */

    if (sk->sk_state & (PPPOX_BOUND | PPPOX_CONNECTED | PPPOX_ZOMBIE)) {
        ppp_unregister_channel(&pppox_sk(sk)->chan);
        sk->sk_state = PPPOX_DEAD;
    }
}

EXPORT_SYMBOL(register_pppox_proto);
EXPORT_SYMBOL(unregister_pppox_proto);
EXPORT_SYMBOL(pppox_unbind_sock);

int pppox_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
    struct sock *sk = sock->sk;
    struct pppox_sock *po = pppox_sk(sk);
    int rc;

    lock_sock(sk);

    switch (cmd) {
    case PPPIOCGCHAN: {
        int index;
        rc = -ENOTCONN;
        if (!(sk->sk_state & PPPOX_CONNECTED))
            break;

        rc = -EINVAL;
        index = ppp_channel_index(&po->chan);
        if (put_user(index , (int __user *) arg))
            break;

        rc = 0;
        sk->sk_state |= PPPOX_BOUND;
        break;
    }
    default:
        rc = pppox_protos[sk->sk_protocol]->ioctl ?
            pppox_protos[sk->sk_protocol]->ioctl(sock, cmd, arg) : -ENOTTY;
    }

    release_sock(sk);
    return rc;
}

EXPORT_SYMBOL(pppox_ioctl);

static int pppox_create(struct net *net, struct socket *sock, int protocol,
            int kern)
{
    int rc = -EPROTOTYPE;

    if (protocol < 0 || protocol > PX_MAX_PROTO)
        goto out;

    rc = -EPROTONOSUPPORT;
    if (!pppox_protos[protocol])
        request_module("pppox-proto-%d", protocol);
    if (!pppox_protos[protocol] ||
        !try_module_get(pppox_protos[protocol]->owner))
        goto out;

    rc = pppox_protos[protocol]->create(net, sock);

    module_put(pppox_protos[protocol]->owner);
out:
    return rc;
}

static const struct net_proto_family pppox_proto_family = {
    .family = PF_PPPOX,
    .create = pppox_create,
    .owner  = THIS_MODULE,
};

static int __init pppox_init(void)
{
    return sock_register(&pppox_proto_family);
}

static void __exit pppox_exit(void)
{
    sock_unregister(PF_PPPOX);
}

module_init(pppox_init);
module_exit(pppox_exit);

MODULE_AUTHOR("Michal Ostrowski <[email protected]>");
MODULE_DESCRIPTION("PPP over Ethernet driver (generic socket layer)");
MODULE_LICENSE("GPL");