1 /*
2 * AX.25 release 037
3 *
4 * This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * History
13 * AX.25 036 Jonathan(G4KLX) Cloned from ax25_timer.c.
14 * Joerg(DL1BKE) Added DAMA Slave Timeout timer
15 * AX.25 037 Jonathan(G4KLX) New timer architecture.
16 */
17
18 #include <linux/errno.h>
19 #include <linux/types.h>
20 #include <linux/socket.h>
21 #include <linux/in.h>
22 #include <linux/kernel.h>
23 #include <linux/sched.h>
24 #include <linux/timer.h>
25 #include <linux/string.h>
26 #include <linux/sockios.h>
27 #include <linux/net.h>
28 #include <net/ax25.h>
29 #include <linux/inet.h>
30 #include <linux/netdevice.h>
31 #include <linux/skbuff.h>
32 #include <net/sock.h>
33 #include <asm/uaccess.h>
34 #include <asm/system.h>
35 #include <linux/fcntl.h>
36 #include <linux/mm.h>
37 #include <linux/interrupt.h>
38
39 static void ax25_ds_timeout(unsigned long);
40
41 /*
42 * Add DAMA slave timeout timer to timer list.
43 * Unlike the connection based timers the timeout function gets
44 * triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
45 * (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
46 * 1/10th of a second.
47 */
48
49 static void ax25_ds_add_timer(ax25_dev *ax25_dev)
50 {
51 struct timer_list *t = &ax25_dev->dama.slave_timer;
52 t->data = (unsigned long) ax25_dev;
53 t->function = &ax25_ds_timeout;
54 t->expires = jiffies + HZ;
55 add_timer(t);
56 }
57
58 void ax25_ds_del_timer(ax25_dev *ax25_dev)
59 {
60 if (ax25_dev) del_timer(&ax25_dev->dama.slave_timer);
61 }
62
63 void ax25_ds_set_timer(ax25_dev *ax25_dev)
64 {
65 if (ax25_dev == NULL) /* paranoia */
66 return;
67
68 del_timer(&ax25_dev->dama.slave_timer);
69 ax25_dev->dama.slave_timeout = ax25_dev->values[AX25_VALUES_DS_TIMEOUT] / 10;
70 ax25_ds_add_timer(ax25_dev);
71 }
72
73 /*
74 * DAMA Slave Timeout
75 * Silently discard all (slave) connections in case our master forgot us...
76 */
77
78 static void ax25_ds_timeout(unsigned long arg)
79 {
80 ax25_dev *ax25_dev = (struct ax25_dev *) arg;
81 ax25_cb *ax25;
82
83 if (ax25_dev == NULL || !ax25_dev->dama.slave)
84 return; /* Yikes! */
85
86 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
87 ax25_ds_set_timer(ax25_dev);
88 return;
89 }
90
91 for (ax25=ax25_list; ax25 != NULL; ax25 = ax25->next) {
92 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
93 continue;
94
95 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
96 ax25_disconnect(ax25, ETIMEDOUT);
97 }
98
99 ax25_dev_dama_off(ax25_dev);
100 }
101
102 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
103 {
104 switch (ax25->state) {
105
106 case AX25_STATE_0:
107 /* Magic here: If we listen() and a new link dies before it
108 is accepted() it isn't 'dead' so doesn't get removed. */
109 if (ax25->sk == NULL || ax25->sk->destroy || (ax25->sk->state == TCP_LISTEN && ax25->sk->dead)) {
110 ax25_destroy_socket(ax25);
111 return;
112 }
113 break;
114
115 case AX25_STATE_3:
116 /*
117 * Check the state of the receive buffer.
118 */
119 if (ax25->sk != NULL) {
120 if (atomic_read(&ax25->sk->rmem_alloc) < (ax25->sk->rcvbuf / 2) &&
121 (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
122 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
123 ax25->condition &= ~AX25_COND_ACK_PENDING;
124 break;
125 }
126 }
127 break;
128 }
129
130 ax25_start_heartbeat(ax25);
131 }
132
133 /* dl1bke 960114: T3 works much like the IDLE timeout, but
134 * gets reloaded with every frame for this
135 * connection.
136 */
137 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
138 {
139 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
140 ax25_dama_off(ax25);
141 ax25_disconnect(ax25, ETIMEDOUT);
142 }
143
144 /* dl1bke 960228: close the connection when IDLE expires.
145 * unlike T3 this timer gets reloaded only on
146 * I frames.
147 */
148 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
149 {
150 ax25_clear_queues(ax25);
151
152 ax25->n2count = 0;
153 ax25->state = AX25_STATE_2;
154
155 ax25_calculate_t1(ax25);
156 ax25_start_t1timer(ax25);
157 ax25_stop_t3timer(ax25);
158
159 if (ax25->sk != NULL) {
160 ax25->sk->state = TCP_CLOSE;
161 ax25->sk->err = 0;
162 ax25->sk->shutdown |= SEND_SHUTDOWN;
163 if (!ax25->sk->dead)
164 ax25->sk->state_change(ax25->sk);
165 ax25->sk->dead = 1;
166 }
167 }
168
169 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
170 * within the poll of any connected channel. Remember
171 * that we are not allowed to send anything unless we
172 * get polled by the Master.
173 *
174 * Thus we'll have to do parts of our T1 handling in
175 * ax25_enquiry_response().
176 */
177 void ax25_ds_t1_timeout(ax25_cb *ax25)
178 {
179 switch (ax25->state) {
180
181 case AX25_STATE_1:
182 if (ax25->n2count == ax25->n2) {
183 if (ax25->modulus == AX25_MODULUS) {
184 ax25_disconnect(ax25, ETIMEDOUT);
185 return;
186 } else {
187 ax25->modulus = AX25_MODULUS;
188 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
189 ax25->n2count = 0;
190 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
191 }
192 } else {
193 ax25->n2count++;
194 if (ax25->modulus == AX25_MODULUS)
195 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
196 else
197 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
198 }
199 break;
200
201 case AX25_STATE_2:
202 if (ax25->n2count == ax25->n2) {
203 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
204 ax25_disconnect(ax25, ETIMEDOUT);
205 return;
206 } else {
207 ax25->n2count++;
208 }
209 break;
210
211 case AX25_STATE_3:
212 if (ax25->n2count == ax25->n2) {
213 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
214 ax25_disconnect(ax25, ETIMEDOUT);
215 return;
216 } else {
217 ax25->n2count++;
218 }
219 break;
220 }
221
222 ax25_calculate_t1(ax25);
223 ax25_start_t1timer(ax25);
224 }
225
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