/*
* AX.25 release 032
*
* 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 1.2.1 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.
*
* History
* AX.25 028a Jonathan(G4KLX) New state machine based on SDL diagrams.
* AX.25 028b Jonathan(G4KLX) Extracted AX25 control block from the
* sock structure.
* AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names.
* AX.25 031 Joerg(DL1BKE) Added DAMA support
* AX.25 032 Joerg(DL1BKE) Fixed DAMA timeout bug
*/
#include <linux/config.h>
#ifdef CONFIG_AX25
#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 <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#ifdef CONFIG_NETROM
#include <net/netrom.h>
#endif
static void ax25_timer(unsigned long);
/*
* Linux set/reset timer routines
*/
void ax25_set_timer(ax25_cb *ax25)
{
unsigned long flags;
save_flags(flags);
cli();
del_timer(&ax25->timer);
restore_flags(flags);
ax25->timer.next = ax25->timer.prev = NULL;
ax25->timer.data = (unsigned long)ax25;
ax25->timer.function = &ax25_timer;
ax25->timer.expires = jiffies + 10;
add_timer(&ax25->timer);
}
static void ax25_reset_timer(ax25_cb *ax25)
{
unsigned long flags;
save_flags(flags);
cli();
del_timer(&ax25->timer);
restore_flags(flags);
ax25->timer.data = (unsigned long)ax25;
ax25->timer.function = &ax25_timer;
ax25->timer.expires = jiffies + 10;
add_timer(&ax25->timer);
}
/*
* AX.25 TIMER
*
* This routine is called every 500ms. Decrement timer by this
* amount - if expired then process the event.
*/
static void ax25_timer(unsigned long param)
{
ax25_cb *ax25 = (ax25_cb *)param;
switch (ax25->state) {
case AX25_STATE_0:
/* Magic here: If we listen() and a new link dies before it
is accepted() it isn't 'dead' so doesn't get removed. */
if (ax25->sk == NULL || ax25->sk->destroy || (ax25->sk->state == TCP_LISTEN && ax25->sk->dead)) {
del_timer(&ax25->timer);
ax25_destroy_socket(ax25);
return;
}
break;
case AX25_STATE_3:
case AX25_STATE_4:
/*
* Check the state of the receive buffer.
*/
if (ax25->sk != NULL) {
if (ax25->sk->rmem_alloc < (ax25->sk->rcvbuf / 2) && (ax25->condition & OWN_RX_BUSY_CONDITION)) {
ax25->condition &= ~OWN_RX_BUSY_CONDITION;
if (!ax25->dama_slave)
ax25_send_control(ax25, RR, POLLOFF, C_RESPONSE);
ax25->condition &= ~ACK_PENDING_CONDITION;
break;
}
}
/*
* Check for frames to transmit.
*/
if (!ax25->dama_slave)
ax25_kick(ax25);
break;
default:
break;
}
if (ax25->t2timer > 0 && --ax25->t2timer == 0) {
if (ax25->state == AX25_STATE_3 || ax25->state == AX25_STATE_4) {
if (ax25->condition & ACK_PENDING_CONDITION) {
ax25->condition &= ~ACK_PENDING_CONDITION;
if (!ax25->dama_slave)
ax25_timeout_response(ax25);
}
}
}
if (ax25->t3timer > 0 && --ax25->t3timer == 0) {
/* dl1bke 960114: T3 expires and we are in DAMA mode: */
/* send a DISC and abort the connection */
if (ax25->dama_slave) {
#ifdef CONFIG_NETROM
nr_link_failed(&ax25->dest_addr, ax25->device);
#endif
ax25_clear_queues(ax25);
ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
ax25->state = AX25_STATE_0;
if (ax25->sk != NULL) {
if (ax25->sk->debug)
printk("T3 Timeout\n");
ax25->sk->state = TCP_CLOSE;
ax25->sk->err = ETIMEDOUT;
if (!ax25->sk->dead)
ax25->sk->state_change(ax25->sk);
ax25->sk->dead = 1;
}
ax25_reset_timer(ax25);
return;
}
if (ax25->state == AX25_STATE_3) {
ax25->n2count = 0;
ax25_transmit_enquiry(ax25);
ax25->state = AX25_STATE_4;
}
ax25->t3timer = ax25->t3;
}
if (ax25->idletimer > 0 && --ax25->idletimer == 0) {
/* dl1bke 960228: close the connection when IDLE expires */
/* similar to DAMA T3 timeout but with */
/* a "clean" disconnect of the connection */
ax25_clear_queues(ax25);
ax25->n2count = 0;
if (!ax25->dama_slave) {
ax25->t3timer = 0;
ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
} else {
ax25->t3timer = ax25->t3;
}
/* state 1 or 2 should not happen, but... */
if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2)
ax25->state = AX25_STATE_0;
else
ax25->state = AX25_STATE_2;
ax25->t1timer = ax25->t1 = ax25_calculate_t1(ax25);
if (ax25->sk != NULL) {
ax25->sk->state = TCP_CLOSE;
ax25->sk->err = 0;
if (!ax25->sk->dead)
ax25->sk->state_change(ax25->sk);
ax25->sk->dead = 1;
ax25->sk->destroy = 1;
}
}
/* dl1bke 960114: DAMA T1 timeouts are handled in ax25_dama_slave_transmit */
/* nevertheless we have to re-enqueue the timer struct... */
if (ax25->t1timer == 0 || --ax25->t1timer > 0) {
ax25_reset_timer(ax25);
return;
}
if (!ax25_dev_is_dama_slave(ax25->device)) {
if (ax25->dama_slave)
ax25->dama_slave = 0;
ax25_t1_timeout(ax25);
}
}
/* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
* within the poll of any connected channel. Remember
* that we are not allowed to send anything unless we
* get polled by the Master.
*
* Thus we'll have to do parts of our T1 handling in
* ax25_enquiry_response().
*/
void ax25_t1_timeout(ax25_cb * ax25)
{
switch (ax25->state) {
case AX25_STATE_1:
if (ax25->n2count == ax25->n2) {
if (ax25->modulus == MODULUS) {
#ifdef CONFIG_NETROM
nr_link_failed(&ax25->dest_addr, ax25->device);
#endif
ax25_clear_queues(ax25);
ax25->state = AX25_STATE_0;
if (ax25->sk != NULL) {
ax25->sk->state = TCP_CLOSE;
ax25->sk->err = ETIMEDOUT;
if (!ax25->sk->dead)
ax25->sk->state_change(ax25->sk);
ax25->sk->dead = 1;
}
} else {
ax25->modulus = MODULUS;
ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW);
ax25->n2count = 0;
ax25_send_control(ax25, SABM, ax25_dev_is_dama_slave(ax25->device)? POLLOFF : POLLON, C_COMMAND);
}
} else {
ax25->n2count++;
if (ax25->modulus == MODULUS) {
ax25_send_control(ax25, SABM, ax25_dev_is_dama_slave(ax25->device)? POLLOFF : POLLON, C_COMMAND);
} else {
ax25_send_control(ax25, SABME, ax25_dev_is_dama_slave(ax25->device)? POLLOFF : POLLON, C_COMMAND);
}
}
break;
case AX25_STATE_2:
if (ax25->n2count == ax25->n2) {
#ifdef CONFIG_NETROM
nr_link_failed(&ax25->dest_addr, ax25->device);
#endif
ax25_clear_queues(ax25);
ax25->state = AX25_STATE_0;
ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
if (ax25->sk != NULL) {
ax25->sk->state = TCP_CLOSE;
ax25->sk->err = ETIMEDOUT;
if (!ax25->sk->dead)
ax25->sk->state_change(ax25->sk);
ax25->sk->dead = 1;
}
} else {
ax25->n2count++;
if (!ax25_dev_is_dama_slave(ax25->device))
ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
}
break;
case AX25_STATE_3:
ax25->n2count = 1;
if (!ax25->dama_slave)
ax25_transmit_enquiry(ax25);
ax25->state = AX25_STATE_4;
break;
case AX25_STATE_4:
if (ax25->n2count == ax25->n2) {
#ifdef CONFIG_NETROM
nr_link_failed(&ax25->dest_addr, ax25->device);
#endif
ax25_clear_queues(ax25);
ax25_send_control(ax25, DM, POLLON, C_RESPONSE);
ax25->state = AX25_STATE_0;
if (ax25->sk != NULL) {
if (ax25->sk->debug)
printk("Link Failure\n");
ax25->sk->state = TCP_CLOSE;
ax25->sk->err = ETIMEDOUT;
if (!ax25->sk->dead)
ax25->sk->state_change(ax25->sk);
ax25->sk->dead = 1;
}
} else {
ax25->n2count++;
if (!ax25->dama_slave)
ax25_transmit_enquiry(ax25);
}
break;
}
ax25->t1timer = ax25->t1 = ax25_calculate_t1(ax25);
ax25_set_timer(ax25);
}
#endif
