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|
/*
* "LAPB via ethernet" driver release 001
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* 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 LAPB over Ethernet.
*
* This driver can use any ethernet destination address, and can be
* limited to accept frames from one dedicated ethernet card only.
*
* History
* LAPBETH 001 Jonathan Naylor Cloned from bpqether.c
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
* 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support
*/
#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 <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/lapb.h>
#include <linux/init.h>
#include <net/x25device.h>
static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
/* If this number is made larger, check that the temporary string buffer
* in lapbeth_new_device is large enough to store the probe device name.*/
#define MAXLAPBDEV 100
struct lapbethdev {
struct list_head node;
struct net_device *ethdev; /* link to ethernet device */
struct net_device *axdev; /* lapbeth device (lapb#) */
};
static LIST_HEAD(lapbeth_devices);
/* ------------------------------------------------------------------------ */
/*
* Get the LAPB device for the ethernet device
*/
static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
{
struct lapbethdev *lapbeth;
list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {
if (lapbeth->ethdev == dev)
return lapbeth;
}
return NULL;
}
static __inline__ int dev_is_ethdev(struct net_device *dev)
{
return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
}
/* ------------------------------------------------------------------------ */
/*
* Receive a LAPB frame via an ethernet interface.
*/
static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
{
int len, err;
struct lapbethdev *lapbeth;
if (dev_net(dev) != &init_net)
goto drop;
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
return NET_RX_DROP;
if (!pskb_may_pull(skb, 2))
goto drop;
rcu_read_lock();
lapbeth = lapbeth_get_x25_dev(dev);
if (!lapbeth)
goto drop_unlock;
if (!netif_running(lapbeth->axdev))
goto drop_unlock;
len = skb->data[0] + skb->data[1] * 256;
dev->stats.rx_packets++;
dev->stats.rx_bytes += len;
skb_pull(skb, 2); /* Remove the length bytes */
skb_trim(skb, len); /* Set the length of the data */
if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
goto drop_unlock;
}
out:
rcu_read_unlock();
return 0;
drop_unlock:
kfree_skb(skb);
goto out;
drop:
kfree_skb(skb);
return 0;
}
static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
{
unsigned char *ptr;
skb_push(skb, 1);
if (skb_cow(skb, 1))
return NET_RX_DROP;
ptr = skb->data;
*ptr = 0x00;
skb->protocol = x25_type_trans(skb, dev);
return netif_rx(skb);
}
/*
* Send a LAPB frame via an ethernet interface
*/
static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
struct net_device *dev)
{
int err;
/*
* Just to be *really* sure not to send anything if the interface
* is down, the ethernet device may have gone.
*/
if (!netif_running(dev))
goto drop;
switch (skb->data[0]) {
case 0x00:
break;
case 0x01:
if ((err = lapb_connect_request(dev)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_connect_request "
"error: %d\n", err);
goto drop;
case 0x02:
if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_disconnect_request "
"err: %d\n", err);
/* Fall thru */
default:
goto drop;
}
skb_pull(skb, 1);
if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
goto drop;
}
out:
return NETDEV_TX_OK;
drop:
kfree_skb(skb);
goto out;
}
static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
{
struct lapbethdev *lapbeth = netdev_priv(ndev);
unsigned char *ptr;
struct net_device *dev;
int size = skb->len;
skb->protocol = htons(ETH_P_X25);
ptr = skb_push(skb, 2);
*ptr++ = size % 256;
*ptr++ = size / 256;
ndev->stats.tx_packets++;
ndev->stats.tx_bytes += size;
skb->dev = dev = lapbeth->ethdev;
dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
dev_queue_xmit(skb);
}
static void lapbeth_connected(struct net_device *dev, int reason)
{
unsigned char *ptr;
struct sk_buff *skb = dev_alloc_skb(1);
if (!skb) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x01;
skb->protocol = x25_type_trans(skb, dev);
netif_rx(skb);
}
static void lapbeth_disconnected(struct net_device *dev, int reason)
{
unsigned char *ptr;
struct sk_buff *skb = dev_alloc_skb(1);
if (!skb) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x02;
skb->protocol = x25_type_trans(skb, dev);
netif_rx(skb);
}
/*
* Set AX.25 callsign
*/
static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
{
struct sockaddr *sa = addr;
memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
return 0;
}
static struct lapb_register_struct lapbeth_callbacks = {
.connect_confirmation = lapbeth_connected,
.connect_indication = lapbeth_connected,
.disconnect_confirmation = lapbeth_disconnected,
.disconnect_indication = lapbeth_disconnected,
.data_indication = lapbeth_data_indication,
.data_transmit = lapbeth_data_transmit,
};
/*
* open/close a device
*/
static int lapbeth_open(struct net_device *dev)
{
int err;
if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
return -ENODEV;
}
netif_start_queue(dev);
return 0;
}
static int lapbeth_close(struct net_device *dev)
{
int err;
|