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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070021#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/fcntl.h>
29#include <linux/mm.h>
30#include <linux/interrupt.h>
31
32static void ax25_ds_timeout(unsigned long);
33
34/*
35 * Add DAMA slave timeout timer to timer list.
36 * Unlike the connection based timers the timeout function gets
37 * triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
38 * (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
39 * 1/10th of a second.
40 */
41
Jarek Poplawskie848b582008-02-11 21:38:32 -080042void ax25_ds_setup_timer(ax25_dev *ax25_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070043{
Jarek Poplawskie848b582008-02-11 21:38:32 -080044 setup_timer(&ax25_dev->dama.slave_timer, ax25_ds_timeout,
45 (unsigned long)ax25_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046}
47
48void ax25_ds_del_timer(ax25_dev *ax25_dev)
49{
50 if (ax25_dev)
51 del_timer(&ax25_dev->dama.slave_timer);
52}
53
54void ax25_ds_set_timer(ax25_dev *ax25_dev)
55{
56 if (ax25_dev == NULL) /* paranoia */
57 return;
58
Ralf Baechlee1fdb5b2006-05-03 23:27:16 -070059 ax25_dev->dama.slave_timeout =
60 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
Jarek Poplawskie848b582008-02-11 21:38:32 -080061 mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062}
63
64/*
65 * DAMA Slave Timeout
66 * Silently discard all (slave) connections in case our master forgot us...
67 */
68
69static void ax25_ds_timeout(unsigned long arg)
70{
71 ax25_dev *ax25_dev = (struct ax25_dev *) arg;
72 ax25_cb *ax25;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74 if (ax25_dev == NULL || !ax25_dev->dama.slave)
75 return; /* Yikes! */
76
77 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
78 ax25_ds_set_timer(ax25_dev);
79 return;
80 }
81
Ralf Baechlec19c4b92006-07-12 13:25:23 -070082 spin_lock(&ax25_list_lock);
Sasha Levinb67bfe02013-02-27 17:06:00 -080083 ax25_for_each(ax25, &ax25_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
85 continue;
86
87 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
88 ax25_disconnect(ax25, ETIMEDOUT);
89 }
Ralf Baechlec19c4b92006-07-12 13:25:23 -070090 spin_unlock(&ax25_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92 ax25_dev_dama_off(ax25_dev);
93}
94
95void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
96{
97 struct sock *sk=ax25->sk;
98
99 if (sk)
100 bh_lock_sock(sk);
101
102 switch (ax25->state) {
103
104 case AX25_STATE_0:
Basil Gunn4a7d99e2016-06-16 09:42:30 -0700105 case AX25_STATE_2:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 /* Magic here: If we listen() and a new link dies before it
107 is accepted() it isn't 'dead' so doesn't get removed. */
108 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
109 (sk->sk_state == TCP_LISTEN &&
110 sock_flag(sk, SOCK_DEAD))) {
111 if (sk) {
112 sock_hold(sk);
113 ax25_destroy_socket(ax25);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 bh_unlock_sock(sk);
Basil Gunn4a7d99e2016-06-16 09:42:30 -0700115 /* Ungrab socket and destroy it */
Bernard Pidoux F6BVPd71b0e92010-08-26 11:40:00 +0000116 sock_put(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 } 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) <
Eric Dumazetf16f3022008-01-13 22:29:41 -0800129 (sk->sk_rcvbuf >> 1) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 (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 */
149void 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 */
160void 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 */
192void 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);
Basil Gunn4a7d99e2016-06-16 09:42:30 -0700218 if (!sock_flag(ax25->sk, SOCK_DESTROY))
219 ax25_disconnect(ax25, ETIMEDOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 return;
221 } else {
222 ax25->n2count++;
223 }
224 break;
225
226 case AX25_STATE_3:
227 if (ax25->n2count == ax25->n2) {
228 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
229 ax25_disconnect(ax25, ETIMEDOUT);
230 return;
231 } else {
232 ax25->n2count++;
233 }
234 break;
235 }
236
237 ax25_calculate_t1(ax25);
238 ax25_start_t1timer(ax25);
239}