ethertap_kern.c

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/*
 * Copyright (C) 2001 Lennert Buytenhek ([email protected]) and
 * James Leu ([email protected]).
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Copyright (C) 2001 by various other people who didn't put their name here.
 * Licensed under the GPL.
 */

#include <linux/init.h>
#include <linux/netdevice.h>
#include "etap.h"
#include <net_kern.h>

struct ethertap_init {
    char *dev_name;
    char *gate_addr;
};

static void etap_init(struct net_device *dev, void *data)
{
    struct uml_net_private *pri;
    struct ethertap_data *epri;
    struct ethertap_init *init = data;

    pri = netdev_priv(dev);
    epri = (struct ethertap_data *) pri->user;
    epri->dev_name = init->dev_name;
    epri->gate_addr = init->gate_addr;
    epri->data_fd = -1;
    epri->control_fd = -1;
    epri->dev = dev;

    printk(KERN_INFO "ethertap backend - %s", epri->dev_name);
    if (epri->gate_addr != NULL)
        printk(KERN_CONT ", IP = %s", epri->gate_addr);
    printk(KERN_CONT "\n");
}

static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
    int len;

    len = net_recvfrom(fd, skb_mac_header(skb),
               skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
    if (len <= 0)
        return(len);

    skb_pull(skb, 2);
    len -= 2;
    return len;
}

static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
    skb_push(skb, 2);
    return net_send(fd, skb->data, skb->len);
}

const struct net_kern_info ethertap_kern_info = {
    .init           = etap_init,
    .protocol       = eth_protocol,
    .read           = etap_read,
    .write          = etap_write,
};

int ethertap_setup(char *str, char **mac_out, void *data)
{
    struct ethertap_init *init = data;

    *init = ((struct ethertap_init)
        { .dev_name     = NULL,
          .gate_addr    = NULL });
    if (tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
                &init->gate_addr))
        return 0;
    if (init->dev_name == NULL) {
        printk(KERN_ERR "ethertap_setup : Missing tap device name\n");
        return 0;
    }

    return 1;
}

static struct transport ethertap_transport = {
    .list       = LIST_HEAD_INIT(ethertap_transport.list),
    .name       = "ethertap",
    .setup      = ethertap_setup,
    .user       = &ethertap_user_info,
    .kern       = &ethertap_kern_info,
    .private_size   = sizeof(struct ethertap_data),
    .setup_size     = sizeof(struct ethertap_init),
};

static int register_ethertap(void)
{
    register_transport(&ethertap_transport);
    return 0;
}

late_initcall(register_ethertap);