summaryrefslogtreecommitdiff
path: root/net/ax25/ax25_ds_timer.c
blob: 3a8b67316fc388d31360d999f0ebb35367328cff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
/*
 * This program 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.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/spinlock.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/tcp.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>

static void ax25_ds_timeout(unsigned long);

/*
 *	Add DAMA slave timeout timer to timer list.
 *	Unlike the connection based timers the timeout function gets
 *	triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
 *	(aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
 *	1/10th of a second.
 */

static void ax25_ds_add_timer(ax25_dev *ax25_dev)
{
	struct timer_list *t = &ax25_dev->dama.slave_timer;
	t->data		= (unsigned long) ax25_dev;
	t->function	= &ax25_ds_timeout;
	t->expires	= jiffies + HZ;
	add_timer(t);
}

void ax25_ds_del_timer(ax25_dev *ax25_dev)
{
	if (ax25_dev)
		del_timer(&ax25_dev->dama.slave_timer);
}

void ax25_ds_set_timer(ax25_dev *ax25_dev)
{
	if (ax25_dev == NULL)		/* paranoia */
		return;

	del_timer(&ax25_dev->dama.slave_timer);
	ax25_dev->dama.slave_timeout = ax25_dev->values[AX25_VALUES_DS_TIMEOUT] / 10;
	ax25_ds_add_timer(ax25_dev);
}

/*
 *	DAMA Slave Timeout
 *	Silently discard all (slave) connections in case our master forgot us...
 */

static void ax25_ds_timeout(unsigned long arg)
{
	ax25_dev *ax25_dev = (struct ax25_dev *) arg;
	ax25_cb *ax25;
	struct hlist_node *node;

	if (ax25_dev == NULL || !ax25_dev->dama.slave)
		return;			/* Yikes! */

	if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
		ax25_ds_set_timer(ax25_dev);
		return;
	}

	spin_lock_bh(&ax25_list_lock);
	ax25_for_each(ax25, node, &ax25_list) {
		if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
			continue;

		ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
		ax25_disconnect(ax25, ETIMEDOUT);
	}
	spin_unlock_bh(&ax25_list_lock);

	ax25_dev_dama_off(ax25_dev);
}

void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
{
	struct sock *sk=ax25->sk;

	if (sk)
		bh_lock_sock(sk);

	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 (!sk || sock_flag(sk, SOCK_DESTROY) ||
		    (sk->sk_state == TCP_LISTEN &&
		     sock_flag(sk, SOCK_DEAD))) {
			if (sk) {
				sock_hold(sk);
				ax25_destroy_socket(ax25);
				sock_put(sk);
				bh_unlock_sock(sk);
			} else
				ax25_destroy_socket(ax25);
			return;
		}
		break;

	case AX25_STATE_3:
		/*
		 * Check the state of the receive buffer.
		 */
		if (sk != NULL) {
			if (atomic_read(&sk->sk_rmem_alloc) <
			    (sk->sk_rcvbuf / 2) &&
			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
				ax25->condition &= ~AX25_COND_ACK_PENDING;
				break;
			}
		}
		break;
	}

	if (sk)
		bh_unlock_sock(sk);

	ax25_start_heartbeat(ax25);
}

/* dl1bke 960114: T3 works much like the IDLE timeout, but
 *                gets reloaded with every frame for this
 *		  connection.
 */
void ax25_ds_t3timer_expiry(ax25_cb *ax25)
{
	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
	ax25_dama_off(ax25);
	ax25_disconnect(ax25, ETIMEDOUT);
}

/* dl1bke 960228: close the connection when IDLE expires.
 *		  unlike T3 this timer gets reloaded only on
 *		  I frames.
 */
void ax25_ds_idletimer_expiry(ax25_cb *ax25)
{
	ax25_clear_queues(ax25);

	ax25->n2count = 0;
	ax25->state = AX25_STATE_2;

	ax25_calculate_t1(ax25);
	ax25_start_t1timer(ax25);
	ax25_stop_t3timer(ax25);

	if (ax25->sk != NULL) {
		bh_lock_sock(ax25->sk);
		ax25->sk->sk_state     = TCP_CLOSE;
		ax25->sk->sk_err       = 0;
		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
			ax25->sk->sk_state_change(ax25->sk);
			sock_set_flag(ax25->sk, SOCK_DEAD);
		}
		bh_unlock_sock(ax25->sk);
	}
}

/* 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_ds_t1_timeout(ax25_cb *ax25)
{
	switch (ax25->state) {
	case AX25_STATE_1:
		if (ax25->n2count == ax25->n2) {
			if (ax25->modulus == AX25_MODULUS) {
				ax25_disconnect(ax25, ETIMEDOUT);
				return;
			} else {
				ax25->modulus = AX25_MODULUS;
				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
				ax25->n2count = 0;
				ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
			}
		} else {
			ax25->n2count++;
			if (ax25->modulus == AX25_MODULUS)
				ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
			else
				ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
		}
		break;

	case AX25_STATE_2:
		if (ax25->n2count == ax25->n2) {
			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
			ax25_disconnect(ax25, ETIMEDOUT);
			return;
		} else {
			ax25->n2count++;
		}
		break;

	case AX25_STATE_3:
		if (ax25->n2count == ax25->n2) {
			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
			ax25_disconnect(ax25, ETIMEDOUT);
			return;
		} else {
			ax25->n2count++;
		}
		break;
	}

	ax25_calculate_t1(ax25);
	ax25_start_t1timer(ax25);
}