1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
6 */
7 #include <linux/errno.h>
8 #include <linux/types.h>
9 #include <linux/socket.h>
10 #include <linux/spinlock.h>
11 #include <linux/in.h>
12 #include <linux/kernel.h>
13 #include <linux/jiffies.h>
14 #include <linux/timer.h>
15 #include <linux/string.h>
16 #include <linux/sockios.h>
17 #include <linux/net.h>
18 #include <net/tcp_states.h>
19 #include <net/ax25.h>
20 #include <linux/inet.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <net/sock.h>
24 #include <linux/uaccess.h>
25 #include <linux/fcntl.h>
26 #include <linux/mm.h>
27 #include <linux/interrupt.h>
28
29 static void ax25_ds_timeout(struct timer_list *);
30
31 /*
32 * Add DAMA slave timeout timer to timer list.
33 * Unlike the connection based timers the timeout function gets
34 * triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
35 * (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
36 * 1/10th of a second.
37 */
38
39 void ax25_ds_setup_timer(ax25_dev *ax25_dev)
40 {
41 timer_setup(&ax25_dev->dama.slave_timer, ax25_ds_timeout, 0);
42 }
43
44 void ax25_ds_del_timer(ax25_dev *ax25_dev)
45 {
46 if (ax25_dev)
47 del_timer(&ax25_dev->dama.slave_timer);
48 }
49
50 void ax25_ds_set_timer(ax25_dev *ax25_dev)
51 {
52 if (ax25_dev == NULL) /* paranoia */
53 return;
54
55 ax25_dev->dama.slave_timeout =
56 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
57 mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
58 }
59
60 /*
61 * DAMA Slave Timeout
62 * Silently discard all (slave) connections in case our master forgot us...
63 */
64
65 static void ax25_ds_timeout(struct timer_list *t)
66 {
67 ax25_dev *ax25_dev = from_timer(ax25_dev, t, dama.slave_timer);
68 ax25_cb *ax25;
69
70 if (ax25_dev == NULL || !ax25_dev->dama.slave)
71 return; /* Yikes! */
72
73 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
74 ax25_ds_set_timer(ax25_dev);
75 return;
76 }
77
78 spin_lock(&ax25_list_lock);
79 ax25_for_each(ax25, &ax25_list) {
80 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
81 continue;
82
83 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
84 ax25_disconnect(ax25, ETIMEDOUT);
85 }
86 spin_unlock(&ax25_list_lock);
87
88 ax25_dev_dama_off(ax25_dev);
89 }
90
91 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
92 {
93 struct sock *sk=ax25->sk;
94
95 if (sk)
96 bh_lock_sock(sk);
97
98 switch (ax25->state) {
99
100 case AX25_STATE_0:
101 case AX25_STATE_2:
102 /* Magic here: If we listen() and a new link dies before it
103 is accepted() it isn't 'dead' so doesn't get removed. */
104 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
105 (sk->sk_state == TCP_LISTEN &&
106 sock_flag(sk, SOCK_DEAD))) {
107 if (sk) {
108 sock_hold(sk);
109 ax25_destroy_socket(ax25);
110 bh_unlock_sock(sk);
111 /* Ungrab socket and destroy it */
112 sock_put(sk);
113 } else
114 ax25_destroy_socket(ax25);
115 return;
116 }
117 break;
118
119 case AX25_STATE_3:
120 /*
121 * Check the state of the receive buffer.
122 */
123 if (sk != NULL) {
124 if (atomic_read(&sk->sk_rmem_alloc) <
125 (sk->sk_rcvbuf >> 1) &&
126 (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
127 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
128 ax25->condition &= ~AX25_COND_ACK_PENDING;
129 break;
130 }
131 }
132 break;
133 }
134
135 if (sk)
136 bh_unlock_sock(sk);
137
138 ax25_start_heartbeat(ax25);
139 }
140
141 /* dl1bke 960114: T3 works much like the IDLE timeout, but
142 * gets reloaded with every frame for this
143 * connection.
144 */
145 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
146 {
147 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
148 ax25_dama_off(ax25);
149 ax25_disconnect(ax25, ETIMEDOUT);
150 }
151
152 /* dl1bke 960228: close the connection when IDLE expires.
153 * unlike T3 this timer gets reloaded only on
154 * I frames.
155 */
156 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
157 {
158 ax25_clear_queues(ax25);
159
160 ax25->n2count = 0;
161 ax25->state = AX25_STATE_2;
162
163 ax25_calculate_t1(ax25);
164 ax25_start_t1timer(ax25);
165 ax25_stop_t3timer(ax25);
166
167 if (ax25->sk != NULL) {
168 bh_lock_sock(ax25->sk);
169 ax25->sk->sk_state = TCP_CLOSE;
170 ax25->sk->sk_err = 0;
171 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
172 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
173 ax25->sk->sk_state_change(ax25->sk);
174 sock_set_flag(ax25->sk, SOCK_DEAD);
175 }
176 bh_unlock_sock(ax25->sk);
177 }
178 }
179
180 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
181 * within the poll of any connected channel. Remember
182 * that we are not allowed to send anything unless we
183 * get polled by the Master.
184 *
185 * Thus we'll have to do parts of our T1 handling in
186 * ax25_enquiry_response().
187 */
188 void ax25_ds_t1_timeout(ax25_cb *ax25)
189 {
190 switch (ax25->state) {
191 case AX25_STATE_1:
192 if (ax25->n2count == ax25->n2) {
193 if (ax25->modulus == AX25_MODULUS) {
194 ax25_disconnect(ax25, ETIMEDOUT);
195 return;
196 } else {
197 ax25->modulus = AX25_MODULUS;
198 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
199 ax25->n2count = 0;
200 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
201 }
202 } else {
203 ax25->n2count++;
204 if (ax25->modulus == AX25_MODULUS)
205 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
206 else
207 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
208 }
209 break;
210
211 case AX25_STATE_2:
212 if (ax25->n2count == ax25->n2) {
213 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
214 if (!sock_flag(ax25->sk, SOCK_DESTROY))
215 ax25_disconnect(ax25, ETIMEDOUT);
216 return;
217 } else {
218 ax25->n2count++;
219 }
220 break;
221
222 case AX25_STATE_3:
223 if (ax25->n2count == ax25->n2) {
224 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
225 ax25_disconnect(ax25, ETIMEDOUT);
226 return;
227 } else {
228 ax25->n2count++;
229 }
230 break;
231 }
232
233 ax25_calculate_t1(ax25);
234 ax25_start_t1timer(ax25);
235 }
236
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