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/net/x25/x25_timer.c

https://bitbucket.org/abioy/linux
C | 174 lines | 110 code | 31 blank | 33 comment | 10 complexity | fe36e04bbc8f74bb7e1517237c74db8d MD5 | raw file
Possible License(s): CC-BY-SA-3.0, GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 *	X.25 Packet Layer release 002
  3 *
  4 *	This is ALPHA test software. This code may break your machine,
  5 *	randomly fail to work with new releases, misbehave and/or generally
  6 *	screw up. It might even work.
  7 *
  8 *	This code REQUIRES 2.1.15 or higher
  9 *
 10 *	This module:
 11 *		This module is free software; you can redistribute it and/or
 12 *		modify it under the terms of the GNU General Public License
 13 *		as published by the Free Software Foundation; either version
 14 *		2 of the License, or (at your option) any later version.
 15 *
 16 *	History
 17 *	X.25 001	Jonathan Naylor	Started coding.
 18 *	X.25 002	Jonathan Naylor	New timer architecture.
 19 *					Centralised disconnection processing.
 20 */
 21
 22#include <linux/errno.h>
 23#include <linux/jiffies.h>
 24#include <linux/timer.h>
 25#include <net/sock.h>
 26#include <net/tcp_states.h>
 27#include <net/x25.h>
 28
 29static void x25_heartbeat_expiry(unsigned long);
 30static void x25_timer_expiry(unsigned long);
 31
 32void x25_init_timers(struct sock *sk)
 33{
 34	struct x25_sock *x25 = x25_sk(sk);
 35
 36	setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);
 37
 38	/* initialized by sock_init_data */
 39	sk->sk_timer.data     = (unsigned long)sk;
 40	sk->sk_timer.function = &x25_heartbeat_expiry;
 41}
 42
 43void x25_start_heartbeat(struct sock *sk)
 44{
 45	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
 46}
 47
 48void x25_stop_heartbeat(struct sock *sk)
 49{
 50	del_timer(&sk->sk_timer);
 51}
 52
 53void x25_start_t2timer(struct sock *sk)
 54{
 55	struct x25_sock *x25 = x25_sk(sk);
 56
 57	mod_timer(&x25->timer, jiffies + x25->t2);
 58}
 59
 60void x25_start_t21timer(struct sock *sk)
 61{
 62	struct x25_sock *x25 = x25_sk(sk);
 63
 64	mod_timer(&x25->timer, jiffies + x25->t21);
 65}
 66
 67void x25_start_t22timer(struct sock *sk)
 68{
 69	struct x25_sock *x25 = x25_sk(sk);
 70
 71	mod_timer(&x25->timer, jiffies + x25->t22);
 72}
 73
 74void x25_start_t23timer(struct sock *sk)
 75{
 76	struct x25_sock *x25 = x25_sk(sk);
 77
 78	mod_timer(&x25->timer, jiffies + x25->t23);
 79}
 80
 81void x25_stop_timer(struct sock *sk)
 82{
 83	del_timer(&x25_sk(sk)->timer);
 84}
 85
 86unsigned long x25_display_timer(struct sock *sk)
 87{
 88	struct x25_sock *x25 = x25_sk(sk);
 89
 90	if (!timer_pending(&x25->timer))
 91		return 0;
 92
 93	return x25->timer.expires - jiffies;
 94}
 95
 96static void x25_heartbeat_expiry(unsigned long param)
 97{
 98	struct sock *sk = (struct sock *)param;
 99
100	bh_lock_sock(sk);
101	if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
102		goto restart_heartbeat;
103
104	switch (x25_sk(sk)->state) {
105
106		case X25_STATE_0:
107			/*
108			 * Magic here: If we listen() and a new link dies
109			 * before it is accepted() it isn't 'dead' so doesn't
110			 * get removed.
111			 */
112			if (sock_flag(sk, SOCK_DESTROY) ||
113			    (sk->sk_state == TCP_LISTEN &&
114			     sock_flag(sk, SOCK_DEAD))) {
115				bh_unlock_sock(sk);
116				x25_destroy_socket_from_timer(sk);
117				return;
118			}
119			break;
120
121		case X25_STATE_3:
122			/*
123			 * Check for the state of the receive buffer.
124			 */
125			x25_check_rbuf(sk);
126			break;
127	}
128restart_heartbeat:
129	x25_start_heartbeat(sk);
130	bh_unlock_sock(sk);
131}
132
133/*
134 *	Timer has expired, it may have been T2, T21, T22, or T23. We can tell
135 *	by the state machine state.
136 */
137static inline void x25_do_timer_expiry(struct sock * sk)
138{
139	struct x25_sock *x25 = x25_sk(sk);
140
141	switch (x25->state) {
142
143		case X25_STATE_3:	/* T2 */
144			if (x25->condition & X25_COND_ACK_PENDING) {
145				x25->condition &= ~X25_COND_ACK_PENDING;
146				x25_enquiry_response(sk);
147			}
148			break;
149
150		case X25_STATE_1:	/* T21 */
151		case X25_STATE_4:	/* T22 */
152			x25_write_internal(sk, X25_CLEAR_REQUEST);
153			x25->state = X25_STATE_2;
154			x25_start_t23timer(sk);
155			break;
156
157		case X25_STATE_2:	/* T23 */
158			x25_disconnect(sk, ETIMEDOUT, 0, 0);
159			break;
160	}
161}
162
163static void x25_timer_expiry(unsigned long param)
164{
165	struct sock *sk = (struct sock *)param;
166
167	bh_lock_sock(sk);
168	if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
169		if (x25_sk(sk)->state == X25_STATE_3)
170			x25_start_t2timer(sk);
171	} else
172		x25_do_timer_expiry(sk);
173	bh_unlock_sock(sk);
174}