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/*
* 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.
* X.25 002 Jonathan Naylor Centralised disconnection code.
* New timer architecture.
* 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
* negotiation.
* 2000-11-10 Henner Eisen Check and reset for out-of-sequence
* i-frames.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/ip.h> /* For ip_rcv */
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/x25.h>
static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
{
struct sk_buff *skbo, *skbn = skb;
if (more) {
sk->protinfo.x25->fraglen += skb->len;
skb_queue_tail(&sk->protinfo.x25->fragment_queue, skb);
skb_set_owner_r(skb, sk);
return 0;
}
if (!more && sk->protinfo.x25->fraglen > 0) { /* End of fragment */
int len = sk->protinfo.x25->fraglen + skb->len;
if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
kfree_skb(skb);
return 1;
}
skb_queue_tail(&sk->protinfo.x25->fragment_queue, skb);
skbn->h.raw = skbn->data;
skbo = skb_dequeue(&sk->protinfo.x25->fragment_queue);
memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
kfree_skb(skbo);
while ((skbo = skb_dequeue(&sk->protinfo.x25->fragment_queue)) != NULL) {
skb_pull(skbo, (sk->protinfo.x25->neighbour->extended) ? X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
kfree_skb(skbo);
}
sk->protinfo.x25->fraglen = 0;
}
skb_set_owner_r(skbn, sk);
skb_queue_tail(&sk->receive_queue, skbn);
if (!sk->dead)
sk->data_ready(sk,skbn->len);
return 0;
}
/*
* State machine for state 1, Awaiting Call Accepted State.
* The handling of the timer(s) is in file x25_timer.c.
* Handling of state 0 and connection release is in af_x25.c.
*/
static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
x25_address source_addr, dest_addr;
switch (frametype) {
case X25_CALL_ACCEPTED:
x25_stop_timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->vl = 0;
sk->protinfo.x25->state = X25_STATE_3;
sk->state = TCP_ESTABLISHED;
/*
* Parse the data in the frame.
*/
skb_pull(skb, X25_STD_MIN_LEN);
skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
skb_pull(skb, x25_parse_facilities(skb, &sk->protinfo.x25->facilities, &sk->protinfo.x25->vc_facil_mask));
/*
* Copy any Call User Data.
*/
if (skb->len >= 0) {
memcpy(sk->protinfo.x25->calluserdata.cuddata, skb->data, skb->len);
sk->protinfo.x25->calluserdata.cudlength = skb->len;
}
if (!sk->dead)
sk->state_change(sk);
break;
case X25_CLEAR_REQUEST:
x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
break;
default:
break;
}
return 0;
}
/*
* State machine for state 2, Awaiting Clear Confirmation State.
* The handling of the timer(s) is in file x25_timer.c
* Handling of state 0 and connection release is in af_x25.c.
*/
static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
switch (frametype) {
case X25_CLEAR_REQUEST:
x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
break;
case X25_CLEAR_CONFIRMATION:
x25_disconnect(sk, 0, 0, 0);
break;
default:
break;
}
return 0;
}
/*
* State machine for state 3, Connected State.
* The handling of the timer(s) is in file x25_timer.c
* Handling of state 0 and connection release is in af_x25.c.
*/
static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
{
int queued = 0;
int modulus;
modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
switch (frametype) {
case X25_RESET_REQUEST:
x25_write_internal(sk, X25_RESET_CONFIRMATION);
x25_stop_timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vl = 0;
x25_requeue_frames(sk);
break;
case X25_CLEAR_REQUEST:
x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
break;
case X25_RR:
case X25_RNR:
if (!x25_validate_nr(sk, nr)) {
x25_clear_queues(sk);
x25_write_internal(sk, X25_RESET_REQUEST);
x25_start_t22timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vl = 0;
sk->protinfo.x25->state = X25_STATE_4;
} else {
x25_frames_acked(sk, nr);
if (frametype == X25_RNR) {
sk->protinfo.x25->condition |= X25_COND_PEER_RX_BUSY;
} else {
sk->protinfo.x25->condition &= ~X25_COND_PEER_RX_BUSY;
}
}
break;
case X25_DATA: /* XXX */
sk->protinfo.x25->condition &= ~X25_COND_PEER_RX_BUSY;
if ((ns!=sk->protinfo.x25->vr) ||
!x25_validate_nr(sk, nr)) {
x25_clear_queues(sk);
x25_write_internal(sk, X25_RESET_REQUEST);
x25_start_t22timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vl = 0;
sk->protinfo.x25->state = X25_STATE_4;
break;
}
x25_frames_acked(sk, nr);
if (ns == sk->protinfo.x25->vr) {
if (x25_queue_rx_frame(sk, skb, m) == 0) {
sk->protinfo.x25->vr = (sk->protinfo.x25->vr + 1) % modulus;
queued = 1;
} else {
/* Should never happen */
x25_clear_queues(sk);
x25_write_internal(sk, X25_RESET_REQUEST);
x25_start_t22timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vl = 0;
sk->protinfo.x25->state = X25_STATE_4;
break;
}
if (atomic_read(&sk->rmem_alloc) > (sk->rcvbuf / 2))
sk->protinfo.x25->condition |= X25_COND_OWN_RX_BUSY;
}
/*
* If the window is full Ack it immediately, else
* start the holdback timer.
*/
if (((sk->protinfo.x25->vl + sk->protinfo.x25->facilities.winsize_in) % modulus) == sk->protinfo.x25->vr) {
sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;
x25_stop_timer(sk);
x25_enquiry_response(sk);
} else {
sk->protinfo.x25->condition |= X25_COND_ACK_PENDING;
x25_start_t2timer(sk);
}
break;
case X25_INTERRUPT_CONFIRMATION:
sk->protinfo.x25->intflag = 0;
break;
case X25_INTERRUPT:
if (sk->urginline) {
queued = (sock_queue_rcv_skb(sk, skb) == 0);
} else {
skb_set_owner_r(skb, sk);
skb_queue_tail(&sk->protinfo.x25->interrupt_in_queue, skb);
queued = 1;
}
if (sk->proc != 0) {
if (sk->proc > 0)
kill_proc(sk->proc, SIGURG, 1);
else
kill_pg(-sk->proc, SIGURG, 1);
sock_wake_async(sk->socket, 3, POLL_PRI);
}
x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
break;
default:
printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
break;
}
return queued;
}
/*
* State machine for state 4, Awaiting Reset Confirmation State.
* The handling of the timer(s) is in file x25_timer.c
* Handling of state 0 and connection release is in af_x25.c.
*/
static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
switch (frametype) {
case X25_RESET_REQUEST:
x25_write_internal(sk, X25_RESET_CONFIRMATION);
case X25_RESET_CONFIRMATION:
x25_stop_timer(sk);
sk->protinfo.x25->condition = 0x00;
sk->protinfo.x25->va = 0;
sk->protinfo.x25->vr = 0;
sk->protinfo.x25->vs = 0;
sk->protinfo.x25->vl = 0;
sk->protinfo.x25->state = X25_STATE_3;
x25_requeue_frames(sk);
break;
case X25_CLEAR_REQUEST:
x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
break;
default:
break;
}
return 0;
}
/* Higher level upcall for a LAPB frame */
int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
int queued = 0, frametype, ns, nr, q, d, m;
if (sk->protinfo.x25->state == X25_STATE_0)
return 0;
frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
switch (sk->protinfo.x25->state) {
case X25_STATE_1:
queued = x25_state1_machine(sk, skb, frametype);
break;
case X25_STATE_2:
queued = x25_state2_machine(sk, skb, frametype);
break;
case X25_STATE_3:
queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
break;
case X25_STATE_4:
queued = x25_state4_machine(sk, skb, frametype);
break;
}
x25_kick(sk);
return queued;
}
int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
int queued;
queued = x25_process_rx_frame(sk,skb);
if(!queued) kfree_skb(skb);
return 0;
}
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