/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- x25_receive_data
- x25_lapb_receive_frame
- x25_establish_link
- x25_terminate_link
- x25_send_frame
/*
* X.25 Packet Layer release 002
*
* 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 2.1.15 or higher
*
* 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.
*
* History
* X.25 001 Jonathan Naylor Started coding.
* 2000-09-04 Henner Eisen Prevent freeing a dangling skb.
*/
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/if_arp.h>
#include <net/x25.h>
static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
{
struct sock *sk;
unsigned short frametype;
unsigned int lci;
frametype = skb->data[2];
lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
/*
* LCI of zero is always for us, and its always a link control
* frame.
*/
if (lci == 0) {
x25_link_control(skb, nb, frametype);
return 0;
}
/*
* Find an existing socket.
*/
if ((sk = x25_find_socket(lci, nb)) != NULL) {
int queued = 1;
skb_reset_transport_header(skb);
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
queued = x25_process_rx_frame(sk, skb);
} else {
sk_add_backlog(sk, skb);
}
bh_unlock_sock(sk);
sock_put(sk);
return queued;
}
/*
* Is is a Call Request ? if so process it.
*/
if (frametype == X25_CALL_REQUEST)
return x25_rx_call_request(skb, nb, lci);
/*
* Its not a Call Request, nor is it a control frame.
* Can we forward it?
*/
if (x25_forward_data(lci, nb, skb)) {
if (frametype == X25_CLEAR_CONFIRMATION) {
x25_clear_forward_by_lci(lci);
}
kfree_skb(skb);
return 1;
}
/*
x25_transmit_clear_request(nb, lci, 0x0D);
*/
if (frametype != X25_CLEAR_CONFIRMATION)
printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
return 0;
}
int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
struct packet_type *ptype, struct net_device *orig_dev)
{
struct sk_buff *nskb;
struct x25_neigh *nb;
if (!net_eq(dev_net(dev), &init_net))
goto drop;
nskb = skb_copy(skb, GFP_ATOMIC);
if (!nskb)
goto drop;
kfree_skb(skb);
skb = nskb;
/*
* Packet received from unrecognised device, throw it away.
*/
nb = x25_get_neigh(dev);
if (!nb) {
printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
goto drop;
}
switch (skb->data[0]) {
case 0x00:
skb_pull(skb, 1);
if (x25_receive_data(skb, nb)) {
x25_neigh_put(nb);
goto out;
}
break;
case 0x01:
x25_link_established(nb);
break;
case 0x02:
x25_link_terminated(nb);
break;
}
x25_neigh_put(nb);
drop:
kfree_skb(skb);
out:
return 0;
}
void x25_establish_link(struct x25_neigh *nb)
{
struct sk_buff *skb;
unsigned char *ptr;
switch (nb->dev->type) {
case ARPHRD_X25:
if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
printk(KERN_ERR "x25_dev: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x01;
break;
#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
case ARPHRD_ETHER:
return;
#endif
default:
return;
}
skb->protocol = htons(ETH_P_X25);
skb->dev = nb->dev;
dev_queue_xmit(skb);
}
void x25_terminate_link(struct x25_neigh *nb)
{
struct sk_buff *skb;
unsigned char *ptr;
#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
if (nb->dev->type == ARPHRD_ETHER)
return;
#endif
if (nb->dev->type != ARPHRD_X25)
return;
skb = alloc_skb(1, GFP_ATOMIC);
if (!skb) {
printk(KERN_ERR "x25_dev: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x02;
skb->protocol = htons(ETH_P_X25);
skb->dev = nb->dev;
dev_queue_xmit(skb);
}
void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
{
unsigned char *dptr;
skb_reset_network_header(skb);
switch (nb->dev->type) {
case ARPHRD_X25:
dptr = skb_push(skb, 1);
*dptr = 0x00;
break;
#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
case ARPHRD_ETHER:
kfree_skb(skb);
return;
#endif
default:
kfree_skb(skb);
return;
}
skb->protocol = htons(ETH_P_X25);
skb->dev = nb->dev;
dev_queue_xmit(skb);
}