forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
216 lines
4.0 KiB
216 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* 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 |
|
* |
|
* History |
|
* X.25 001 Jonathan Naylor Started coding. |
|
* 2000-09-04 Henner Eisen Prevent freeing a dangling skb. |
|
*/ |
|
|
|
#define pr_fmt(fmt) "X25: " fmt |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/netdevice.h> |
|
#include <linux/skbuff.h> |
|
#include <linux/slab.h> |
|
#include <net/sock.h> |
|
#include <linux/if_arp.h> |
|
#include <net/x25.h> |
|
#include <net/x25device.h> |
|
|
|
static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb) |
|
{ |
|
struct sock *sk; |
|
unsigned short frametype; |
|
unsigned int lci; |
|
|
|
if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) |
|
return 0; |
|
|
|
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 { |
|
queued = !sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); |
|
} |
|
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) |
|
pr_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) { |
|
pr_debug("unknown neighbour - %s\n", dev->name); |
|
goto drop; |
|
} |
|
|
|
if (!pskb_may_pull(skb, 1)) { |
|
x25_neigh_put(nb); |
|
return 0; |
|
} |
|
|
|
switch (skb->data[0]) { |
|
|
|
case X25_IFACE_DATA: |
|
skb_pull(skb, 1); |
|
if (x25_receive_data(skb, nb)) { |
|
x25_neigh_put(nb); |
|
goto out; |
|
} |
|
break; |
|
|
|
case X25_IFACE_CONNECT: |
|
x25_link_established(nb); |
|
break; |
|
|
|
case X25_IFACE_DISCONNECT: |
|
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) { |
|
pr_err("x25_dev: out of memory\n"); |
|
return; |
|
} |
|
ptr = skb_put(skb, 1); |
|
*ptr = X25_IFACE_CONNECT; |
|
break; |
|
|
|
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 (nb->dev->type != ARPHRD_X25) |
|
return; |
|
|
|
skb = alloc_skb(1, GFP_ATOMIC); |
|
if (!skb) { |
|
pr_err("x25_dev: out of memory\n"); |
|
return; |
|
} |
|
|
|
ptr = skb_put(skb, 1); |
|
*ptr = X25_IFACE_DISCONNECT; |
|
|
|
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 = X25_IFACE_DATA; |
|
break; |
|
|
|
default: |
|
kfree_skb(skb); |
|
return; |
|
} |
|
|
|
skb->protocol = htons(ETH_P_X25); |
|
skb->dev = nb->dev; |
|
|
|
dev_queue_xmit(skb); |
|
}
|
|
|