1 /*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
6 * screw up. It might even work.
7 *
8 * This code REQUIRES 2.1.15 or higher
9 *
10 * This module:
11 * This module is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * History
17 * X.25 001 Jonathan Naylor Started coding.
18 * X.25 002 Jonathan Naylor New timer architecture.
19 * Centralised disconnection processing.
20 */
21
22 #include <linux/errno.h>
23 #include <linux/jiffies.h>
24 #include <linux/timer.h>
25 #include <net/sock.h>
26 #include <net/tcp_states.h>
27 #include <net/x25.h>
28
29 static void x25_heartbeat_expiry(unsigned long);
30 static void x25_timer_expiry(unsigned long);
31
32 void x25_init_timers(struct sock *sk)
33 {
34 struct x25_sock *x25 = x25_sk(sk);
35
36 setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);
37
38 /* initialized by sock_init_data */
39 sk->sk_timer.data = (unsigned long)sk;
40 sk->sk_timer.function = &x25_heartbeat_expiry;
41 }
42
43 void x25_start_heartbeat(struct sock *sk)
44 {
45 mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
46 }
47
48 void x25_stop_heartbeat(struct sock *sk)
49 {
50 del_timer(&sk->sk_timer);
51 }
52
53 void x25_start_t2timer(struct sock *sk)
54 {
55 struct x25_sock *x25 = x25_sk(sk);
56
57 mod_timer(&x25->timer, jiffies + x25->t2);
58 }
59
60 void x25_start_t21timer(struct sock *sk)
61 {
62 struct x25_sock *x25 = x25_sk(sk);
63
64 mod_timer(&x25->timer, jiffies + x25->t21);
65 }
66
67 void x25_start_t22timer(struct sock *sk)
68 {
69 struct x25_sock *x25 = x25_sk(sk);
70
71 mod_timer(&x25->timer, jiffies + x25->t22);
72 }
73
74 void x25_start_t23timer(struct sock *sk)
75 {
76 struct x25_sock *x25 = x25_sk(sk);
77
78 mod_timer(&x25->timer, jiffies + x25->t23);
79 }
80
81 void x25_stop_timer(struct sock *sk)
82 {
83 del_timer(&x25_sk(sk)->timer);
84 }
85
86 unsigned long x25_display_timer(struct sock *sk)
87 {
88 struct x25_sock *x25 = x25_sk(sk);
89
90 if (!timer_pending(&x25->timer))
91 return 0;
92
93 return x25->timer.expires - jiffies;
94 }
95
96 static void x25_heartbeat_expiry(unsigned long param)
97 {
98 struct sock *sk = (struct sock *)param;
99
100 bh_lock_sock(sk);
101 if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
102 goto restart_heartbeat;
103
104 switch (x25_sk(sk)->state) {
105
106 case X25_STATE_0:
107 /*
108 * Magic here: If we listen() and a new link dies
109 * before it is accepted() it isn't 'dead' so doesn't
110 * get removed.
111 */
112 if (sock_flag(sk, SOCK_DESTROY) ||
113 (sk->sk_state == TCP_LISTEN &&
114 sock_flag(sk, SOCK_DEAD))) {
115 bh_unlock_sock(sk);
116 x25_destroy_socket_from_timer(sk);
117 return;
118 }
119 break;
120
121 case X25_STATE_3:
122 /*
123 * Check for the state of the receive buffer.
124 */
125 x25_check_rbuf(sk);
126 break;
127 }
128 restart_heartbeat:
129 x25_start_heartbeat(sk);
130 bh_unlock_sock(sk);
131 }
132
133 /*
134 * Timer has expired, it may have been T2, T21, T22, or T23. We can tell
135 * by the state machine state.
136 */
137 static inline void x25_do_timer_expiry(struct sock * sk)
138 {
139 struct x25_sock *x25 = x25_sk(sk);
140
141 switch (x25->state) {
142
143 case X25_STATE_3: /* T2 */
144 if (x25->condition & X25_COND_ACK_PENDING) {
145 x25->condition &= ~X25_COND_ACK_PENDING;
146 x25_enquiry_response(sk);
147 }
148 break;
149
150 case X25_STATE_1: /* T21 */
151 case X25_STATE_4: /* T22 */
152 x25_write_internal(sk, X25_CLEAR_REQUEST);
153 x25->state = X25_STATE_2;
154 x25_start_t23timer(sk);
155 break;
156
157 case X25_STATE_2: /* T23 */
158 x25_disconnect(sk, ETIMEDOUT, 0, 0);
159 break;
160 }
161 }
162
163 static void x25_timer_expiry(unsigned long param)
164 {
165 struct sock *sk = (struct sock *)param;
166
167 bh_lock_sock(sk);
168 if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
169 if (x25_sk(sk)->state == X25_STATE_3)
170 x25_start_t2timer(sk);
171 } else
172 x25_do_timer_expiry(sk);
173 bh_unlock_sock(sk);
174 }
175
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