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(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(m: ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10; |
57 | mod_timer(timer: &ax25_dev->dama.slave_timer, expires: 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(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(lock: &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, flag: SOCK_DESTROY) || |
105 | (sk->sk_state == TCP_LISTEN && |
106 | sock_flag(sk, flag: 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(v: &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(sk: ax25->sk, flag: SOCK_DEAD)) { |
173 | ax25->sk->sk_state_change(ax25->sk); |
174 | sock_set_flag(sk: ax25->sk, flag: 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(sk: ax25->sk, flag: 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 | |