170 lines
3.6 KiB
C
170 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* X.25 Packet Layer release 002
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*
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* This is ALPHA test software. This code may break your machine,
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* randomly fail to work with new releases, misbehave and/or generally
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* screw up. It might even work.
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*
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* This code REQUIRES 2.1.15 or higher
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*
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* History
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* X.25 001 Jonathan Naylor Started coding.
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* X.25 002 Jonathan Naylor New timer architecture.
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* Centralised disconnection processing.
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*/
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#include <linux/errno.h>
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#include <linux/jiffies.h>
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#include <linux/timer.h>
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#include <net/sock.h>
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#include <net/tcp_states.h>
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#include <net/x25.h>
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static void x25_heartbeat_expiry(struct timer_list *t);
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static void x25_timer_expiry(struct timer_list *t);
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void x25_init_timers(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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timer_setup(&x25->timer, x25_timer_expiry, 0);
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/* initialized by sock_init_data */
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sk->sk_timer.function = x25_heartbeat_expiry;
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}
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void x25_start_heartbeat(struct sock *sk)
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{
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mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
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}
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void x25_stop_heartbeat(struct sock *sk)
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{
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del_timer(&sk->sk_timer);
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}
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void x25_start_t2timer(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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mod_timer(&x25->timer, jiffies + x25->t2);
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}
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void x25_start_t21timer(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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mod_timer(&x25->timer, jiffies + x25->t21);
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}
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void x25_start_t22timer(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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mod_timer(&x25->timer, jiffies + x25->t22);
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}
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void x25_start_t23timer(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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mod_timer(&x25->timer, jiffies + x25->t23);
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}
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void x25_stop_timer(struct sock *sk)
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{
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del_timer(&x25_sk(sk)->timer);
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}
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unsigned long x25_display_timer(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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if (!timer_pending(&x25->timer))
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return 0;
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return x25->timer.expires - jiffies;
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}
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static void x25_heartbeat_expiry(struct timer_list *t)
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{
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struct sock *sk = from_timer(sk, t, sk_timer);
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
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goto restart_heartbeat;
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switch (x25_sk(sk)->state) {
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case X25_STATE_0:
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/*
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* Magic here: If we listen() and a new link dies
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* before it is accepted() it isn't 'dead' so doesn't
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* get removed.
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*/
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if (sock_flag(sk, SOCK_DESTROY) ||
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(sk->sk_state == TCP_LISTEN &&
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sock_flag(sk, SOCK_DEAD))) {
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bh_unlock_sock(sk);
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x25_destroy_socket_from_timer(sk);
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return;
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}
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break;
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case X25_STATE_3:
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/*
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* Check for the state of the receive buffer.
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*/
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x25_check_rbuf(sk);
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break;
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}
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restart_heartbeat:
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x25_start_heartbeat(sk);
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bh_unlock_sock(sk);
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}
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/*
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* Timer has expired, it may have been T2, T21, T22, or T23. We can tell
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* by the state machine state.
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*/
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static inline void x25_do_timer_expiry(struct sock * sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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switch (x25->state) {
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case X25_STATE_3: /* T2 */
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if (x25->condition & X25_COND_ACK_PENDING) {
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x25->condition &= ~X25_COND_ACK_PENDING;
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x25_enquiry_response(sk);
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}
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break;
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case X25_STATE_1: /* T21 */
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case X25_STATE_4: /* T22 */
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x25_write_internal(sk, X25_CLEAR_REQUEST);
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x25->state = X25_STATE_2;
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x25_start_t23timer(sk);
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break;
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case X25_STATE_2: /* T23 */
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x25_disconnect(sk, ETIMEDOUT, 0, 0);
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break;
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}
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}
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static void x25_timer_expiry(struct timer_list *t)
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{
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struct x25_sock *x25 = from_timer(x25, t, timer);
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struct sock *sk = &x25->sk;
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
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if (x25_sk(sk)->state == X25_STATE_3)
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x25_start_t2timer(sk);
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} else
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x25_do_timer_expiry(sk);
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bh_unlock_sock(sk);
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}
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