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/*
* G8BPQ compatible "AX.25 via ethernet" driver release 004
*
* 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.
* Fixed to match Linux networking
* changes - 2.1.15.
* BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
*/
#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_ether.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <net/ip.h>
#include <net/arp.h>
#include <linux/bpqether.h>
static char banner[] __initdata = KERN_INFO "AX.25: bpqether driver version 004\n";
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 net_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 = {
type: __constant_htons(ETH_P_BPQ),
func: bpq_rcv,
};
static struct notifier_block bpq_dev_notifier = {
notifier_call: bpq_device_event,
};
#define MAXBPQDEV 100
static struct bpqdev {
struct bpqdev *next;
char ethname[14]; /* ether device name */
struct net_device *ethdev; /* link to ethernet device */
struct net_device axdev; /* bpq device (bpq#) */
struct net_device_stats stats; /* some statistics */
char dest_addr[6]; /* ether destination address */
char acpt_addr[6]; /* accept ether frames from this address only */
} *bpq_devices;
/* ------------------------------------------------------------------------ */
/*
* Get the ethernet device for a BPQ device
*/
static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
{
struct bpqdev *bpq = (struct bpqdev *) dev->priv;
return bpq ? bpq->ethdev : NULL;
}
/*
* Get the BPQ device for the ethernet device
*/
static inline struct net_device *bpq_get_ax25_dev(struct net_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 net_device *dev)
{
return (
dev->type == ARPHRD_ETHER
&& strncmp(dev->name, "dummy", 5)
);
}
/*
* 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 net_device *dev)
{
struct bpqdev *bpq, *bpq_prev, *bpq_next;
int result = 0;
unsigned long flags;
save_flags(flags);
cli();
bpq_prev = NULL;
for (bpq = bpq_devices; bpq != NULL; bpq = bpq_next) {
bpq_next = 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;
/* We should be locked, call
* unregister_netdevice directly
*/
unregister_netdevice(&bpq->axdev);
kfree(bpq);
}
else
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 net_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 || !netif_running(dev)) {
kfree_skb(skb);
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);
return 0;
}
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 */
bpq->stats.rx_packets++;
bpq->stats.rx_bytes += len;
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 net_device *dev)
{
struct sk_buff *newskb;
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 (!netif_running(dev)) {
bpq_check_devices(dev);
kfree_skb(skb);
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! */
if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
printk(KERN_WARNING "bpqether: out of memory\n");
kfree_skb(skb);
return -ENOMEM;
}
if (skb->sk != NULL)
skb_set_owner_w(newskb, skb->sk);
kfree_skb(skb);
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;
if ((dev = bpq_get_ether_dev(dev)) == NULL) {
bpq->stats.tx_dropped++;
kfree_skb(skb);
return -ENODEV;
}
skb->dev = dev;
skb->nh.raw = skb->data;
dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
bpq->stats.tx_packets++;
bpq->stats.tx_bytes+=skb->len;
dev_queue_xmit(skb);
netif_wake_queue(dev);
return 0;
}
/*
* Statistics
*/
static struct net_device_stats *bpq_get_stats(struct net_device *dev)
{
struct bpqdev *bpq = (struct bpqdev *) dev->priv;
return &bpq->stats;
}
/*
* Set AX.25 callsign
*/
static int bpq_set_mac_address(struct net_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 net_device *dev, struct ifreq *ifr, int cmd)
{
struct bpq_ethaddr *ethaddr = (struct bpq_ethaddr *)ifr->ifr_data;
struct bpqdev *bpq = dev->priv;
struct bpq_req req;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (bpq == NULL) /* woops! */
return -ENODEV;
switch (cmd) {
case SIOCSBPQETHOPT:
if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
return -EFAULT;
switch (req.cmd) {
case SIOCGBPQETHPARAM:
case SIOCSBPQETHPARAM:
default:
return -EINVAL;
}
break;
case SIOCSBPQETHADDR:
if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
return -EFAULT;
if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
return -EFAULT;
break;
default:
return -EINVAL;
}
return 0;
}
/*
* open/close a device
*/
static int bpq_open(struct net_device *dev)
{
if (bpq_check_devices(dev))
return -ENODEV; /* oops, it's gone */
MOD_INC_USE_COUNT;
netif_start_queue(dev);
return 0;
}
static int bpq_close(struct net_device *dev)
{
netif_stop_queue(dev);
MOD_DEC_USE_COUNT;
return 0;
}
/*
* currently unused
*/
static int bpq_dev_init(struct net_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;
}
static int bpq_get_info(char *buffer, char **start, off_t offset, int length)
{
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 net_device *dev)
{
int k;
struct bpqdev *bpq, *bpq2;
if ((bpq = 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;
for (k = 0; k < MAXBPQDEV; k++) {
struct net_device *odev;
sprintf(dev->name, "bpq%d", k);
if ((odev = __dev_get_by_name(dev->name)) == NULL || bpq_check_devices(odev))
break;
}
if (k == MAXBPQDEV) {
kfree(bpq);
return -ENODEV;
}
dev->priv = (void *)bpq; /* pointer back */
dev->init = bpq_dev_init;
/* We should be locked, call register_netdevice() directly. */
if (register_netdevice(dev) != 0) {
kfree(bpq);
return -EIO;
}
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);
dev->flags = 0;
#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 net_device *dev = (struct net_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
*/
static int __init bpq_init_driver(void)
{
struct net_device *dev;
dev_add_pack(&bpq_packet_type);
register_netdevice_notifier(&bpq_dev_notifier);
printk(banner);
proc_net_create("bpqether", 0, bpq_get_info);
read_lock_bh(&dev_base_lock);
for (dev = dev_base; dev != NULL; dev = dev->next) {
if (dev_is_ethdev(dev)) {
read_unlock_bh(&dev_base_lock);
bpq_new_device(dev);
read_lock_bh(&dev_base_lock);
}
}
read_unlock_bh(&dev_base_lock);
return 0;
}
static void __exit bpq_cleanup_driver(void)
{
struct bpqdev *bpq;
dev_remove_pack(&bpq_packet_type);
unregister_netdevice_notifier(&bpq_dev_notifier);
proc_net_remove("bpqether");
for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next)
unregister_netdev(&bpq->axdev);
}
MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
MODULE_LICENSE("GPL");
module_init(bpq_init_driver);
module_exit(bpq_cleanup_driver);
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