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// 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.
* X.25 002 Jonathan Naylor New timer architecture.
* Centralised disconnection processing.
*/
#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>
static void x25_heartbeat_expiry(struct timer_list *t);
static void x25_timer_expiry(struct timer_list *t);
void x25_init_timers(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
timer_setup(&x25->timer, x25_timer_expiry, 0);
/* initialized by sock_init_data */
sk->sk_timer.function = x25_heartbeat_expiry;
}
void x25_start_heartbeat(struct sock *sk)
{
mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
}
void x25_stop_heartbeat(struct sock *sk)
{
del_timer(&sk->sk_timer);
}
void x25_start_t2timer(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
mod_timer(&x25->timer, jiffies + x25->t2);
}
void x25_start_t21timer(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
mod_timer(&x25->timer, jiffies + x25->t21);
}
void x25_start_t22timer(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
mod_timer(&x25->timer, jiffies + x25->t22);
}
void x25_start_t23timer(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
mod_timer(&x25->timer, jiffies + x25->t23);
}
void x25_stop_timer(struct sock *sk)
{
del_timer(&x25_sk(sk)->timer);
}
unsigned long x25_display_timer(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
if (!timer_pending(&x25->timer))
return 0;
return x25->timer.expires - jiffies;
}
static void x25_heartbeat_expiry(struct timer_list *t)
{
struct sock *sk = from_timer(sk, t, sk_timer);
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
goto restart_heartbeat;
switch (x25_sk(sk)->state) {
case X25_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 (sock_flag(sk, SOCK_DESTROY) ||
(sk->sk_state == TCP_LISTEN &&
sock_flag(sk, SOCK_DEAD))) {
bh_unlock_sock(sk);
x25_destroy_socket_from_timer(sk);
return;
}
break;
case X25_STATE_3:
/*
* Check for the state of the receive buffer.
*/
x25_check_rbuf(sk);
break;
}
restart_heartbeat:
x25_start_heartbeat(sk);
bh_unlock_sock(sk);
}
/*
* Timer has expired, it may have been T2, T21, T22, or T23. We can tell
* by the state machine state.
*/
static inline void x25_do_timer_expiry(struct sock * sk)
{
struct x25_sock *x25 = x25_sk(sk);
switch (x25->state) {
case X25_STATE_3: /* T2 */
if (x25->condition & X25_COND_ACK_PENDING) {
x25->condition &= ~X25_COND_ACK_PENDING;
x25_enquiry_response(sk);
}
break;
case X25_STATE_1: /* T21 */
case X25_STATE_4: /* T22 */
x25_write_internal(sk, X25_CLEAR_REQUEST);
x25->state = X25_STATE_2;
x25_start_t23timer(sk);
break;
case X25_STATE_2: /* T23 */
x25_disconnect(sk, ETIMEDOUT, 0, 0);
break;
}
}
static void x25_timer_expiry(struct timer_list *t)
{
struct x25_sock *x25 = from_timer(x25, t, timer);
struct sock *sk = &x25->sk;
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
if (x25_sk(sk)->state == X25_STATE_3)
x25_start_t2timer(sk);
} else
x25_do_timer_expiry(sk);
bh_unlock_sock(sk);
}
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