2af190dc5b014ef8f544772d188c668e367f3a90
[linux-2.6.git] / net / x25 / x25_timer.c
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         init_timer(&x25->timer);
37         x25->timer.data     = (unsigned long)sk;
38         x25->timer.function = &x25_timer_expiry;
39
40         /* initialized by sock_init_data */
41         sk->sk_timer.data     = (unsigned long)sk;
42         sk->sk_timer.function = &x25_heartbeat_expiry;
43 }
44
45 void x25_start_heartbeat(struct sock *sk)
46 {
47         mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
48 }
49
50 void x25_stop_heartbeat(struct sock *sk)
51 {
52         del_timer(&sk->sk_timer);
53 }
54
55 void x25_start_t2timer(struct sock *sk)
56 {
57         struct x25_sock *x25 = x25_sk(sk);
58
59         mod_timer(&x25->timer, jiffies + x25->t2);
60 }
61
62 void x25_start_t21timer(struct sock *sk)
63 {
64         struct x25_sock *x25 = x25_sk(sk);
65
66         mod_timer(&x25->timer, jiffies + x25->t21);
67 }
68
69 void x25_start_t22timer(struct sock *sk)
70 {
71         struct x25_sock *x25 = x25_sk(sk);
72
73         mod_timer(&x25->timer, jiffies + x25->t22);
74 }
75
76 void x25_start_t23timer(struct sock *sk)
77 {
78         struct x25_sock *x25 = x25_sk(sk);
79
80         mod_timer(&x25->timer, jiffies + x25->t23);
81 }
82
83 void x25_stop_timer(struct sock *sk)
84 {
85         del_timer(&x25_sk(sk)->timer);
86 }
87
88 unsigned long x25_display_timer(struct sock *sk)
89 {
90         struct x25_sock *x25 = x25_sk(sk);
91
92         if (!timer_pending(&x25->timer))
93                 return 0;
94
95         return x25->timer.expires - jiffies;
96 }
97
98 static void x25_heartbeat_expiry(unsigned long param)
99 {
100         struct sock *sk = (struct sock *)param;
101
102         bh_lock_sock(sk);
103         if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
104                 goto restart_heartbeat;
105
106         switch (x25_sk(sk)->state) {
107
108                 case X25_STATE_0:
109                         /*
110                          * Magic here: If we listen() and a new link dies
111                          * before it is accepted() it isn't 'dead' so doesn't
112                          * get removed.
113                          */
114                         if (sock_flag(sk, SOCK_DESTROY) ||
115                             (sk->sk_state == TCP_LISTEN &&
116                              sock_flag(sk, SOCK_DEAD))) {
117                                 bh_unlock_sock(sk);
118                                 x25_destroy_socket(sk);
119                                 return;
120                         }
121                         break;
122
123                 case X25_STATE_3:
124                         /*
125                          * Check for the state of the receive buffer.
126                          */
127                         x25_check_rbuf(sk);
128                         break;
129         }
130 restart_heartbeat:
131         x25_start_heartbeat(sk);
132         bh_unlock_sock(sk);
133 }
134
135 /*
136  *      Timer has expired, it may have been T2, T21, T22, or T23. We can tell
137  *      by the state machine state.
138  */
139 static inline void x25_do_timer_expiry(struct sock * sk)
140 {
141         struct x25_sock *x25 = x25_sk(sk);
142
143         switch (x25->state) {
144
145                 case X25_STATE_3:       /* T2 */
146                         if (x25->condition & X25_COND_ACK_PENDING) {
147                                 x25->condition &= ~X25_COND_ACK_PENDING;
148                                 x25_enquiry_response(sk);
149                         }
150                         break;
151
152                 case X25_STATE_1:       /* T21 */
153                 case X25_STATE_4:       /* T22 */
154                         x25_write_internal(sk, X25_CLEAR_REQUEST);
155                         x25->state = X25_STATE_2;
156                         x25_start_t23timer(sk);
157                         break;
158
159                 case X25_STATE_2:       /* T23 */
160                         x25_disconnect(sk, ETIMEDOUT, 0, 0);
161                         break;
162         }
163 }
164
165 static void x25_timer_expiry(unsigned long param)
166 {
167         struct sock *sk = (struct sock *)param;
168
169         bh_lock_sock(sk);
170         if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
171                 if (x25_sk(sk)->state == X25_STATE_3)
172                         x25_start_t2timer(sk);
173         } else
174                 x25_do_timer_expiry(sk);
175         bh_unlock_sock(sk);
176 }