Subversion Repositories or1k

/*
 *	G8BPQ compatible "AX.25 via ethernet" driver release 003
 *
 *	This is ALPHA test software. This code may break your machine, randomly
 *	fail to work with new releases, misbehave and/or generally screw up.
 *	It might even work.
 *
 *	This code REQUIRES 2.0.0 or higher/ NET3.029
 *
 *	This module:
 *		This module 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 is a "pseudo" network driver to allow AX.25 over Ethernet
 *	using G8BPQ encapsulation. It has been extracted from the protocol
 *	implementation because
 *
 *		- things got unreadable within the protocol stack
 *		- to cure the protocol stack from "feature-ism"
 *		- a protocol implementation shouldn't need to know on
 *		  which hardware it is running
 *		- user-level programs like the AX.25 utilities shouldn't
 *		  need to know about the hardware.
 *		- IP over ethernet encapsulated AX.25 was impossible
 *		- rxecho.c did not work
 *		- to have room for extensions
 *		- it just deserves to "live" as an own driver
 *
 *	This driver can use any ethernet destination address, and can be
 *	limited to accept frames from one dedicated ethernet card only.
 *
 *	Note that the driver sets up the BPQ devices automagically on
 *	startup or (if started before the "insmod" of an ethernet device)
 *	on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
 *	the ethernet device (in fact: as soon as another ethernet or bpq
 *	device gets "ifconfig"ured).
 *
 *	I have heard that several people are thinking of experiments
 *	with highspeed packet radio using existing ethernet cards.
 *	Well, this driver is prepared for this purpose, just add
 *	your tx key control and a txdelay / tailtime algorithm,
 *	probably some buffering, and /voila/...
 *
 *	History
 *	BPQ   001	Joerg(DL1BKE)		Extracted BPQ code from AX.25
 *						protocol stack and added my own
 *						yet existing patches
 *	BPQ   002	Joerg(DL1BKE)		Scan network device list on
 *						startup.
 *	BPQ   003	Joerg(DL1BKE)		Ethernet destination address
 *						and accepted source address
 *						can be configured by an ioctl()
 *						call.
 */
 
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/firewall.h>
#include <linux/module.h>
#include <linux/net_alias.h>
 
#include <net/ip.h>
#include <net/arp.h>
 
#include <linux/bpqether.h>
 
static unsigned char ax25_bcast[AX25_ADDR_LEN] =
	{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
static unsigned char ax25_defaddr[AX25_ADDR_LEN] =
	{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};
 
static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
 
static char bpq_eth_addr[6];
 
static int bpq_rcv(struct sk_buff *, struct device *, struct packet_type *);
static int bpq_device_event(struct notifier_block *, unsigned long, void *);
static char *bpq_print_ethaddr(unsigned char *);
 
static struct packet_type bpq_packet_type = {
	0,		/* ntohs(ETH_P_BPQ),*/
	0,		/* copy */
	bpq_rcv,
	NULL,
	NULL,
};
 
static struct notifier_block bpq_dev_notifier = {
	bpq_device_event,
	0
};
 
 
#define MAXBPQDEV 100
 
static struct bpqdev {
	struct bpqdev *next;
	char   ethname[14];		/* ether device name */
	struct device *ethdev;		/* link to ethernet device */
	struct device axdev;		/* bpq device (bpq#) */
	struct enet_statistics stats;	/* some statistics */
	char   dest_addr[6];		/* ether destination address */
	char   acpt_addr[6];		/* accept ether frames from this address only */
} *bpq_devices = NULL;
 
 
/* ------------------------------------------------------------------------ */
 
 
/*
 *	Get the ethernet device for a BPQ device
 */
static __inline__ struct device *bpq_get_ether_dev(struct device *dev)
{
	struct bpqdev *bpq;
 
	bpq = (struct bpqdev *)dev->priv;
 
	return (bpq != NULL) ? bpq->ethdev : NULL;
}
 
/*
 *	Get the BPQ device for the ethernet device
 */
static __inline__ struct device *bpq_get_ax25_dev(struct device *dev)
{
	struct bpqdev *bpq;
 
	for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next)
		if (bpq->ethdev == dev)
			return &bpq->axdev;
 
	return NULL;
}
 
static __inline__ int dev_is_ethdev(struct device *dev)
{
	return (
			dev->type == ARPHRD_ETHER
			&& strncmp(dev->name, "dummy", 5)
#ifdef CONFIG_NET_ALIAS
			&& !net_alias_is(dev)
#endif
	);
}
 
/*
 *	Sanity check: remove all devices that ceased to exists and
 *	return '1' if the given BPQ device was affected.
 */
static int bpq_check_devices(struct device *dev)
{
	struct bpqdev *bpq, *bpq_prev;
	int result = 0;
	unsigned long flags;
 
	save_flags(flags);
	cli();
 
	bpq_prev = NULL;
 
	for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next) {
		if (!dev_get(bpq->ethname)) {
			if (bpq_prev)
				bpq_prev->next = bpq->next;
			else
				bpq_devices = bpq->next;
 
			if (&bpq->axdev == dev)
				result = 1;
 
			unregister_netdev(&bpq->axdev);
			kfree(bpq);
		}
 
		bpq_prev = bpq;
	}
 
	restore_flags(flags);
 
	return result;
}
 
 
/* ------------------------------------------------------------------------ */
 
 
/*
 *	Receive an AX.25 frame via an ethernet interface.
 */
static int bpq_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *ptype)
{
	int len;
	char * ptr;
	struct ethhdr *eth = (struct ethhdr *)skb->mac.raw;
	struct bpqdev *bpq;
 
	skb->sk = NULL;		/* Initially we don't know who it's for */
 
	dev = bpq_get_ax25_dev(dev);
 
	if (dev == NULL || dev->start == 0) {
		kfree_skb(skb, FREE_READ);
		return 0;
	}
 
	/*
	 * if we want to accept frames from just one ethernet device
	 * we check the source address of the sender.
	 */
 
	bpq = (struct bpqdev *)dev->priv;
 
	if (!(bpq->acpt_addr[0] & 0x01) && memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN)) {
		printk(KERN_DEBUG "bpqether: wrong dest %s\n", bpq_print_ethaddr(eth->h_source));
		kfree_skb(skb, FREE_READ);
		return 0;
	}
 
	((struct bpqdev *)dev->priv)->stats.rx_packets++;
 
	len = skb->data[0] + skb->data[1] * 256 - 5;
 
	skb_pull(skb, 2);	/* Remove the length bytes */
	skb_trim(skb, len);	/* Set the length of the data */
 
	ptr = skb_push(skb, 1);
	*ptr = 0;
 
	skb->dev = dev;
	skb->protocol = htons(ETH_P_AX25);
	skb->mac.raw = skb->data;
	skb->pkt_type = PACKET_HOST;
 
	netif_rx(skb);
 
	return 0;
}
 
/*
 * 	Send an AX.25 frame via an ethernet interface
 */
static int bpq_xmit(struct sk_buff *skb, struct device *dev)
{
	unsigned char *ptr;
	struct bpqdev *bpq;
	int size;
 
	/*
	 * Just to be *really* sure not to send anything if the interface
	 * is down, the ethernet device may have gone.
	 */
	if (!dev->start) {
		bpq_check_devices(dev);
		dev_kfree_skb(skb, FREE_WRITE);
		return -ENODEV;
	}
 
	skb_pull(skb, 1);
	size = skb->len;
 
	/*
	 * The AX.25 code leaves enough room for the ethernet header, but
	 * sendto() does not.
	 */
	if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {	/* Ough! */
		struct sk_buff *newskb = alloc_skb(skb->len + AX25_BPQ_HEADER_LEN, GFP_ATOMIC);
 
		if (newskb == NULL) {			/* Argh! */
			printk(KERN_WARNING "bpq_xmit: not enough space to add BPQ Ether header\n");
			dev_kfree_skb(skb, FREE_WRITE);
			return -ENOMEM;
		}
 
		newskb->free = 1;
		newskb->arp  = 1;
		if (skb->sk != NULL)
			atomic_add(newskb->truesize, &skb->sk->wmem_alloc);
		newskb->sk   = skb->sk;
 
		skb_reserve(newskb, AX25_BPQ_HEADER_LEN);
		memcpy(skb_put(newskb, size), skb->data, size);
		dev_kfree_skb(skb, FREE_WRITE);
		skb = newskb;
	}
 
	skb->protocol = htons(ETH_P_AX25);
 
	ptr = skb_push(skb, 2);
 
	*ptr++ = (size + 5) % 256;
	*ptr++ = (size + 5) / 256;
 
	bpq = (struct bpqdev *)dev->priv;
	bpq->stats.tx_packets++;
 
	if ((dev = bpq_get_ether_dev(dev)) == NULL) {
		bpq->stats.tx_dropped++;
		dev_kfree_skb(skb, FREE_WRITE);
		return -ENODEV;
	}
 
	skb->dev = dev;
	dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 
	dev_queue_xmit(skb, dev, SOPRI_NORMAL);
 
	return 0;
}
 
/*
 *	Statistics
 */
static struct enet_statistics *bpq_get_stats(struct device *dev)
{
	struct bpqdev *bpq;
 
	bpq = (struct bpqdev *)dev->priv;
 
	return &bpq->stats;
}
 
/*
 *	Set AX.25 callsign
 */
static int bpq_set_mac_address(struct device *dev, void *addr)
{
    struct sockaddr *sa = (struct sockaddr *)addr;
 
    memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 
    return 0;
}
 
/*	Ioctl commands
 *
 *		SIOCSBPQETHOPT		reserved for enhancements
 *		SIOCSBPQETHADDR		set the destination and accepted
 *					source ethernet address (broadcast
 *					or multicast: accept all)
 */
static int bpq_ioctl(struct device *dev, struct ifreq *ifr, int cmd)
{
	int err;
	struct bpq_ethaddr *ethaddr = (struct bpq_ethaddr *)ifr->ifr_data;
	struct bpqdev *bpq = dev->priv;
	struct bpq_req req;
 
	if (!suser())
		return -EPERM;
 
	if (bpq == NULL)		/* woops! */
		return -ENODEV;
 
	switch (cmd) {
		case SIOCSBPQETHOPT:
			if ((err = verify_area(VERIFY_WRITE, ifr->ifr_data, sizeof(struct bpq_req))) != 0)
				return err;
			memcpy_fromfs(&req, ifr->ifr_data, sizeof(struct bpq_req));
			switch (req.cmd) {
				case SIOCGBPQETHPARAM:
				case SIOCSBPQETHPARAM:
				default:
					return -EINVAL;
			}
 
			break;
 
		case SIOCSBPQETHADDR:
			if ((err = verify_area(VERIFY_READ, ethaddr, sizeof(struct bpq_ethaddr))) != 0)
				return err;
			memcpy_fromfs(bpq->dest_addr, ethaddr->destination, ETH_ALEN);
			memcpy_fromfs(bpq->acpt_addr, ethaddr->accept, ETH_ALEN);
			break;
 
		default:
			return -EINVAL;
	}
 
	return 0;
}
 
/*
 * open/close a device
 */
static int bpq_open(struct device *dev)
{
	if (bpq_check_devices(dev))
		return -ENODEV;		/* oops, it's gone */
 
	dev->tbusy = 0;
	dev->start = 1;
 
	MOD_INC_USE_COUNT;
 
	return 0;
}
 
static int bpq_close(struct device *dev)
{
	dev->tbusy = 1;
	dev->start = 0;
 
	MOD_DEC_USE_COUNT;
 
	return 0;
}
 
/*
 * currently unused
 */
static int bpq_dev_init(struct device *dev)
{
	return 0;
}
 
 
/* ------------------------------------------------------------------------ */
 
 
/*
 *	Proc filesystem
 */
static char * bpq_print_ethaddr(unsigned char *e)
{
	static char buf[18];
 
	sprintf(buf, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
		e[0], e[1], e[2], e[3], e[4], e[5]);
 
	return buf;
}
 
int bpq_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
{
	struct bpqdev *bpqdev;
	int len     = 0;
	off_t pos   = 0;
	off_t begin = 0;
 
	cli();
 
	len += sprintf(buffer, "dev   ether      destination        accept from\n");
 
	for (bpqdev = bpq_devices; bpqdev != NULL; bpqdev = bpqdev->next) {
		len += sprintf(buffer + len, "%-5s %-10s %s  ",
			bpqdev->axdev.name, bpqdev->ethname,
			bpq_print_ethaddr(bpqdev->dest_addr));
 
		len += sprintf(buffer + len, "%s\n",
			(bpqdev->acpt_addr[0] & 0x01) ? "*" : bpq_print_ethaddr(bpqdev->acpt_addr));
 
		pos = begin + len;
 
		if (pos < offset) {
			len   = 0;
			begin = pos;
		}
 
		if (pos > offset + length)
			break;
	}
 
	sti();
 
	*start = buffer + (offset - begin);
	len   -= (offset - begin);
 
	if (len > length) len = length;
 
	return len;
}
 
 
/* ------------------------------------------------------------------------ */
 
 
/*
 *	Setup a new device.
 */
static int bpq_new_device(struct device *dev)
{
	int k;
	unsigned char *buf;
	struct bpqdev *bpq, *bpq2;
 
	if ((bpq = (struct bpqdev *)kmalloc(sizeof(struct bpqdev), GFP_KERNEL)) == NULL)
		return -ENOMEM;
 
	memset(bpq, 0, sizeof(struct bpqdev));
 
	bpq->ethdev = dev;
 
	bpq->ethname[sizeof(bpq->ethname)-1] = '\0';
	strncpy(bpq->ethname, dev->name, sizeof(bpq->ethname)-1);
 
	memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
	memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 
	dev = &bpq->axdev;
	buf = (unsigned char *)kmalloc(14, GFP_KERNEL);
 
	for (k = 0; k < MAXBPQDEV; k++) {
		struct device *odev;
 
		sprintf(buf, "bpq%d", k);
 
		if ((odev = dev_get(buf)) == NULL || bpq_check_devices(odev))
			break;
	}
 
	if (k == MAXBPQDEV) {
		kfree(bpq);
		return -ENODEV;
	}
 
	dev->priv = (void *)bpq;	/* pointer back */
	dev->name = buf;
	dev->init = bpq_dev_init;
 
	if (register_netdev(dev) != 0) {
		kfree(bpq);
                return -EIO;
        }
 
	for (k=0; k < DEV_NUMBUFFS; k++)
		skb_queue_head_init(&dev->buffs[k]);
 
	dev->hard_start_xmit = bpq_xmit;
	dev->open	     = bpq_open;
	dev->stop	     = bpq_close;
	dev->set_mac_address = bpq_set_mac_address;
	dev->get_stats	     = bpq_get_stats;
	dev->do_ioctl	     = bpq_ioctl;
 
	memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
	memcpy(dev->dev_addr,  ax25_defaddr, AX25_ADDR_LEN);
 
	/* preset with reasonable values */
 
	dev->flags      = 0;
	dev->family     = AF_INET;
 
#ifdef CONFIG_INET
	dev->pa_addr    = in_aton("192.168.0.1");
	dev->pa_brdaddr = in_aton("192.168.0.255");
	dev->pa_mask    = in_aton("255.255.255.0");
	dev->pa_alen    = 4;
#endif
 
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
	dev->hard_header     = ax25_encapsulate;
	dev->rebuild_header  = ax25_rebuild_header;
#endif
 
	dev->type            = ARPHRD_AX25;
	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
	dev->mtu             = AX25_DEF_PACLEN;
	dev->addr_len        = AX25_ADDR_LEN;
 
	cli();
 
	if (bpq_devices == NULL) {
		bpq_devices = bpq;
	} else {
		for (bpq2 = bpq_devices; bpq2->next != NULL; bpq2 = bpq2->next);
		bpq2->next = bpq;
	}
 
	sti();
 
	return 0;
}
 
 
/*
 *	Handle device status changes.
 */
static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
{
	struct device *dev = (struct device *)ptr;
 
	if (!dev_is_ethdev(dev))
		return NOTIFY_DONE;
 
	bpq_check_devices(NULL);
 
	switch (event) {
		case NETDEV_UP:		/* new ethernet device -> new BPQ interface */
			if (bpq_get_ax25_dev(dev) == NULL)
				bpq_new_device(dev);
			break;
 
		case NETDEV_DOWN:	/* ethernet device closed -> close BPQ interface */
			if ((dev = bpq_get_ax25_dev(dev)) != NULL)
				dev_close(dev);
			break;
 
		default:
			break;
	}
 
	return NOTIFY_DONE;
}
 
 
/* ------------------------------------------------------------------------ */
 
/*
 * Initialize driver. To be called from af_ax25 if not compiled as a
 * module
 */
int bpq_init(void)
{
	struct device *dev;
 
	bpq_packet_type.type  = htons(ETH_P_BPQ);
	dev_add_pack(&bpq_packet_type);
 
	register_netdevice_notifier(&bpq_dev_notifier);
 
	printk(KERN_INFO "AX.25 ethernet driver version 0.01\n");
 
#ifdef CONFIG_PROC_FS
	proc_net_register(&(struct proc_dir_entry) {
		PROC_NET_AX25_BPQETHER, 8, "bpqether",
		S_IFREG | S_IRUGO, 1, 0, 0,
		0, &proc_net_inode_operations,
		bpq_get_info
	});
#endif
 
	for (dev = dev_base; dev != NULL; dev = dev->next) {
		if (dev_is_ethdev(dev))
			bpq_new_device(dev);
	}
 
	return 0;
}
 
#ifdef MODULE
int init_module(void)
{
	register_symtab(NULL);
 
	return bpq_init();
}
 
void cleanup_module(void)
{
	struct bpqdev *bpq;
 
	dev_remove_pack(&bpq_packet_type);
 
	unregister_netdevice_notifier(&bpq_dev_notifier);
 
#ifdef CONFIG_PROC_FS
	proc_net_unregister(PROC_NET_AX25_BPQETHER);
#endif
 
	for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next)
		unregister_netdev(&bpq->axdev);
}
#endif