1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
9 */
10 #include <linux/errno.h>
11 #include <linux/types.h>
12 #include <linux/socket.h>
13 #include <linux/spinlock.h>
14 #include <linux/in.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/timer.h>
18 #include <linux/string.h>
19 #include <linux/sockios.h>
20 #include <linux/net.h>
21 #include <net/tcp_states.h>
22 #include <net/ax25.h>
23 #include <linux/inet.h>
24 #include <linux/netdevice.h>
25 #include <linux/skbuff.h>
26 #include <net/sock.h>
27 #include <asm/uaccess.h>
28 #include <asm/system.h>
29 #include <linux/fcntl.h>
30 #include <linux/mm.h>
31 #include <linux/interrupt.h>
32
33 static void ax25_ds_timeout(unsigned long);
34
35 /*
36 * Add DAMA slave timeout timer to timer list.
37 * Unlike the connection based timers the timeout function gets
38 * triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
39 * (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
40 * 1/10th of a second.
41 */
42
ax25_ds_setup_timer(ax25_dev * ax25_dev)43 void ax25_ds_setup_timer(ax25_dev *ax25_dev)
44 {
45 setup_timer(&ax25_dev->dama.slave_timer, ax25_ds_timeout,
46 (unsigned long)ax25_dev);
47 }
48
ax25_ds_del_timer(ax25_dev * ax25_dev)49 void ax25_ds_del_timer(ax25_dev *ax25_dev)
50 {
51 if (ax25_dev)
52 del_timer(&ax25_dev->dama.slave_timer);
53 }
54
ax25_ds_set_timer(ax25_dev * ax25_dev)55 void ax25_ds_set_timer(ax25_dev *ax25_dev)
56 {
57 if (ax25_dev == NULL) /* paranoia */
58 return;
59
60 ax25_dev->dama.slave_timeout =
61 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
62 mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
63 }
64
65 /*
66 * DAMA Slave Timeout
67 * Silently discard all (slave) connections in case our master forgot us...
68 */
69
ax25_ds_timeout(unsigned long arg)70 static void ax25_ds_timeout(unsigned long arg)
71 {
72 ax25_dev *ax25_dev = (struct ax25_dev *) arg;
73 ax25_cb *ax25;
74 struct hlist_node *node;
75
76 if (ax25_dev == NULL || !ax25_dev->dama.slave)
77 return; /* Yikes! */
78
79 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
80 ax25_ds_set_timer(ax25_dev);
81 return;
82 }
83
84 spin_lock(&ax25_list_lock);
85 ax25_for_each(ax25, node, &ax25_list) {
86 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
87 continue;
88
89 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
90 ax25_disconnect(ax25, ETIMEDOUT);
91 }
92 spin_unlock(&ax25_list_lock);
93
94 ax25_dev_dama_off(ax25_dev);
95 }
96
ax25_ds_heartbeat_expiry(ax25_cb * ax25)97 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
98 {
99 struct sock *sk=ax25->sk;
100
101 if (sk)
102 bh_lock_sock(sk);
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 (!sk || sock_flag(sk, SOCK_DESTROY) ||
110 (sk->sk_state == TCP_LISTEN &&
111 sock_flag(sk, SOCK_DEAD))) {
112 if (sk) {
113 sock_hold(sk);
114 ax25_destroy_socket(ax25);
115 bh_unlock_sock(sk);
116 sock_put(sk);
117 } else
118 ax25_destroy_socket(ax25);
119 return;
120 }
121 break;
122
123 case AX25_STATE_3:
124 /*
125 * Check the state of the receive buffer.
126 */
127 if (sk != NULL) {
128 if (atomic_read(&sk->sk_rmem_alloc) <
129 (sk->sk_rcvbuf >> 1) &&
130 (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
131 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
132 ax25->condition &= ~AX25_COND_ACK_PENDING;
133 break;
134 }
135 }
136 break;
137 }
138
139 if (sk)
140 bh_unlock_sock(sk);
141
142 ax25_start_heartbeat(ax25);
143 }
144
145 /* dl1bke 960114: T3 works much like the IDLE timeout, but
146 * gets reloaded with every frame for this
147 * connection.
148 */
ax25_ds_t3timer_expiry(ax25_cb * ax25)149 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
150 {
151 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
152 ax25_dama_off(ax25);
153 ax25_disconnect(ax25, ETIMEDOUT);
154 }
155
156 /* dl1bke 960228: close the connection when IDLE expires.
157 * unlike T3 this timer gets reloaded only on
158 * I frames.
159 */
ax25_ds_idletimer_expiry(ax25_cb * ax25)160 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
161 {
162 ax25_clear_queues(ax25);
163
164 ax25->n2count = 0;
165 ax25->state = AX25_STATE_2;
166
167 ax25_calculate_t1(ax25);
168 ax25_start_t1timer(ax25);
169 ax25_stop_t3timer(ax25);
170
171 if (ax25->sk != NULL) {
172 bh_lock_sock(ax25->sk);
173 ax25->sk->sk_state = TCP_CLOSE;
174 ax25->sk->sk_err = 0;
175 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
176 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
177 ax25->sk->sk_state_change(ax25->sk);
178 sock_set_flag(ax25->sk, SOCK_DEAD);
179 }
180 bh_unlock_sock(ax25->sk);
181 }
182 }
183
184 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
185 * within the poll of any connected channel. Remember
186 * that we are not allowed to send anything unless we
187 * get polled by the Master.
188 *
189 * Thus we'll have to do parts of our T1 handling in
190 * ax25_enquiry_response().
191 */
ax25_ds_t1_timeout(ax25_cb * ax25)192 void ax25_ds_t1_timeout(ax25_cb *ax25)
193 {
194 switch (ax25->state) {
195 case AX25_STATE_1:
196 if (ax25->n2count == ax25->n2) {
197 if (ax25->modulus == AX25_MODULUS) {
198 ax25_disconnect(ax25, ETIMEDOUT);
199 return;
200 } else {
201 ax25->modulus = AX25_MODULUS;
202 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
203 ax25->n2count = 0;
204 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
205 }
206 } else {
207 ax25->n2count++;
208 if (ax25->modulus == AX25_MODULUS)
209 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
210 else
211 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
212 }
213 break;
214
215 case AX25_STATE_2:
216 if (ax25->n2count == ax25->n2) {
217 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
218 ax25_disconnect(ax25, ETIMEDOUT);
219 return;
220 } else {
221 ax25->n2count++;
222 }
223 break;
224
225 case AX25_STATE_3:
226 if (ax25->n2count == ax25->n2) {
227 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
228 ax25_disconnect(ax25, ETIMEDOUT);
229 return;
230 } else {
231 ax25->n2count++;
232 }
233 break;
234 }
235
236 ax25_calculate_t1(ax25);
237 ax25_start_t1timer(ax25);
238 }
239