hdlc_raw.c

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/*
 * Generic HDLC support routines for Linux
 * HDLC support
 *
 * Copyright (C) 1999 - 2006 Krzysztof Halasa <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License
 * as published by the Free Software Foundation.
 */

#include <linux/errno.h>
#include <linux/hdlc.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pkt_sched.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>


static int raw_ioctl(struct net_device *dev, struct ifreq *ifr);

static __be16 raw_type_trans(struct sk_buff *skb, struct net_device *dev)
{
    return cpu_to_be16(ETH_P_IP);
}

static struct hdlc_proto proto = {
    .type_trans = raw_type_trans,
    .ioctl      = raw_ioctl,
    .module     = THIS_MODULE,
};


static int raw_ioctl(struct net_device *dev, struct ifreq *ifr)
{
    raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
    const size_t size = sizeof(raw_hdlc_proto);
    raw_hdlc_proto new_settings;
    hdlc_device *hdlc = dev_to_hdlc(dev);
    int result;

    switch (ifr->ifr_settings.type) {
    case IF_GET_PROTO:
        if (dev_to_hdlc(dev)->proto != &proto)
            return -EINVAL;
        ifr->ifr_settings.type = IF_PROTO_HDLC;
        if (ifr->ifr_settings.size < size) {
            ifr->ifr_settings.size = size; /* data size wanted */
            return -ENOBUFS;
        }
        if (copy_to_user(raw_s, hdlc->state, size))
            return -EFAULT;
        return 0;

    case IF_PROTO_HDLC:
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;

        if (dev->flags & IFF_UP)
            return -EBUSY;

        if (copy_from_user(&new_settings, raw_s, size))
            return -EFAULT;

        if (new_settings.encoding == ENCODING_DEFAULT)
            new_settings.encoding = ENCODING_NRZ;

        if (new_settings.parity == PARITY_DEFAULT)
            new_settings.parity = PARITY_CRC16_PR1_CCITT;

        result = hdlc->attach(dev, new_settings.encoding,
                      new_settings.parity);
        if (result)
            return result;

        result = attach_hdlc_protocol(dev, &proto,
                          sizeof(raw_hdlc_proto));
        if (result)
            return result;
        memcpy(hdlc->state, &new_settings, size);
        dev->type = ARPHRD_RAWHDLC;
        netif_dormant_off(dev);
        return 0;
    }

    return -EINVAL;
}


static int __init mod_init(void)
{
    register_hdlc_protocol(&proto);
    return 0;
}



static void __exit mod_exit(void)
{
    unregister_hdlc_protocol(&proto);
}


module_init(mod_init);
module_exit(mod_exit);

MODULE_AUTHOR("Krzysztof Halasa <[email protected]>");
MODULE_DESCRIPTION("Raw HDLC protocol support for generic HDLC");
MODULE_LICENSE("GPL v2");