hdlc_generic.c

一个2.4.21版本的嵌入式linux内核

/*
 * Generic HDLC support routines for Linux
 *
 * Copyright (C) 1999 - 2001 Krzysztof Halasa <[e-mail]>
 *
 * 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.
 *
 * Current status:
 *    - this is work in progress
 *    - not heavily tested on SMP
 *    - currently supported:
 *	* raw IP-in-HDLC
 *	* Cisco HDLC
 *	* Frame Relay with ANSI or CCITT LMI (both user and network side)
 *	* PPP
 *	* X.25
 *
 * Use sethdlc utility to set line parameters, protocol and PVCs
 */

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


static const char* version = "HDLC support module revision 1.11";


static int hdlc_change_mtu(struct net_device *dev, int new_mtu)
{
	if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}



static struct net_device_stats *hdlc_get_stats(struct net_device *dev)
{
	return &dev_to_hdlc(dev)->stats;
}



static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
		    struct packet_type *p)
{
	dev_to_hdlc(dev)->netif_rx(skb);
	return 0;
}


#ifndef CONFIG_HDLC_RAW
#define hdlc_raw_ioctl(hdlc, ifr)	-ENOSYS
#endif

#ifndef CONFIG_HDLC_PPP
#define hdlc_ppp_ioctl(hdlc, ifr)	-ENOSYS
#endif

#ifndef CONFIG_HDLC_CISCO
#define hdlc_cisco_ioctl(hdlc, ifr)	-ENOSYS
#endif

#ifndef CONFIG_HDLC_FR
#define hdlc_fr_ioctl(hdlc, ifr)	-ENOSYS
#endif

#ifndef CONFIG_HDLC_X25
#define hdlc_x25_ioctl(hdlc, ifr)	-ENOSYS
#endif


int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	unsigned int proto;

	if (cmd != SIOCWANDEV)
		return -EINVAL;

	switch(ifr->ifr_settings.type) {
	case IF_PROTO_HDLC:
	case IF_PROTO_PPP:
	case IF_PROTO_CISCO:
	case IF_PROTO_FR:
	case IF_PROTO_X25:
		proto = ifr->ifr_settings.type;
		break;

	default:
		proto = hdlc->proto;
	}

	switch(proto) {
	case IF_PROTO_HDLC:	return hdlc_raw_ioctl(hdlc, ifr);
	case IF_PROTO_PPP:	return hdlc_ppp_ioctl(hdlc, ifr);
	case IF_PROTO_CISCO:	return hdlc_cisco_ioctl(hdlc, ifr);
	case IF_PROTO_FR:	return hdlc_fr_ioctl(hdlc, ifr);
	case IF_PROTO_X25:	return hdlc_x25_ioctl(hdlc, ifr);
	default:		return -EINVAL;
	}
}



int register_hdlc_device(hdlc_device *hdlc)
{
	int result;
	struct net_device *dev = hdlc_to_dev(hdlc);

	dev->get_stats = hdlc_get_stats;
	dev->change_mtu = hdlc_change_mtu;
	dev->mtu = HDLC_MAX_MTU;

	dev->type = ARPHRD_RAWHDLC;
	dev->hard_header_len = 16;

	dev->flags = IFF_POINTOPOINT | IFF_NOARP;

	hdlc->proto = -1;
	hdlc->proto_detach = NULL;

	result = dev_alloc_name(dev, "hdlc%d");
	if (result<0)
		return result;

	result = register_netdev(dev);
	if (result != 0)
		return -EIO;

	MOD_INC_USE_COUNT;
	return 0;
}



void unregister_hdlc_device(hdlc_device *hdlc)
{
	hdlc_proto_detach(hdlc);

	unregister_netdev(hdlc_to_dev(hdlc));
	MOD_DEC_USE_COUNT;
}



MODULE_AUTHOR("Krzysztof Halasa <[e-mail]>");
MODULE_DESCRIPTION("HDLC support module");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(hdlc_ioctl);
EXPORT_SYMBOL(register_hdlc_device);
EXPORT_SYMBOL(unregister_hdlc_device);

struct packet_type hdlc_packet_type=
{
        __constant_htons(ETH_P_HDLC),
        NULL,
        hdlc_rcv,
        NULL,
        NULL
};


static int __init hdlc_module_init(void)
{
	printk(KERN_INFO "%s\n", version);
        dev_add_pack(&hdlc_packet_type);
	return 0;
}



static void __exit hdlc_module_exit(void)
{
	dev_remove_pack(&hdlc_packet_type);
}


module_init(hdlc_module_init);
module_exit(hdlc_module_exit);