tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
29static void x25_heartbeat_expiry(struct timer_list *t);
30static void x25_timer_expiry(struct timer_list *t);
31
32void x25_init_timers(struct sock *sk)
33{
34 struct x25_sock *x25 = x25_sk(sk);
35
36 timer_setup(&x25->timer, x25_timer_expiry, 0);
37
38 /* initialized by sock_init_data */
39 sk->sk_timer.function = x25_heartbeat_expiry;
40}
41
42void x25_start_heartbeat(struct sock *sk)
43{
44 mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
45}
46
47void x25_stop_heartbeat(struct sock *sk)
48{
49 del_timer(&sk->sk_timer);
50}
51
52void x25_start_t2timer(struct sock *sk)
53{
54 struct x25_sock *x25 = x25_sk(sk);
55
56 mod_timer(&x25->timer, jiffies + x25->t2);
57}
58
59void x25_start_t21timer(struct sock *sk)
60{
61 struct x25_sock *x25 = x25_sk(sk);
62
63 mod_timer(&x25->timer, jiffies + x25->t21);
64}
65
66void x25_start_t22timer(struct sock *sk)
67{
68 struct x25_sock *x25 = x25_sk(sk);
69
70 mod_timer(&x25->timer, jiffies + x25->t22);
71}
72
73void x25_start_t23timer(struct sock *sk)
74{
75 struct x25_sock *x25 = x25_sk(sk);
76
77 mod_timer(&x25->timer, jiffies + x25->t23);
78}
79
80void x25_stop_timer(struct sock *sk)
81{
82 del_timer(&x25_sk(sk)->timer);
83}
84
85unsigned long x25_display_timer(struct sock *sk)
86{
87 struct x25_sock *x25 = x25_sk(sk);
88
89 if (!timer_pending(&x25->timer))
90 return 0;
91
92 return x25->timer.expires - jiffies;
93}
94
95static void x25_heartbeat_expiry(struct timer_list *t)
96{
97 struct sock *sk = from_timer(sk, t, sk_timer);
98
99 bh_lock_sock(sk);
100 if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
101 goto restart_heartbeat;
102
103 switch (x25_sk(sk)->state) {
104
105 case X25_STATE_0:
106 /*
107 * Magic here: If we listen() and a new link dies
108 * before it is accepted() it isn't 'dead' so doesn't
109 * get removed.
110 */
111 if (sock_flag(sk, SOCK_DESTROY) ||
112 (sk->sk_state == TCP_LISTEN &&
113 sock_flag(sk, SOCK_DEAD))) {
114 bh_unlock_sock(sk);
115 x25_destroy_socket_from_timer(sk);
116 return;
117 }
118 break;
119
120 case X25_STATE_3:
121 /*
122 * Check for the state of the receive buffer.
123 */
124 x25_check_rbuf(sk);
125 break;
126 }
127restart_heartbeat:
128 x25_start_heartbeat(sk);
129 bh_unlock_sock(sk);
130}
131
132/*
133 * Timer has expired, it may have been T2, T21, T22, or T23. We can tell
134 * by the state machine state.
135 */
136static inline void x25_do_timer_expiry(struct sock * sk)
137{
138 struct x25_sock *x25 = x25_sk(sk);
139
140 switch (x25->state) {
141
142 case X25_STATE_3: /* T2 */
143 if (x25->condition & X25_COND_ACK_PENDING) {
144 x25->condition &= ~X25_COND_ACK_PENDING;
145 x25_enquiry_response(sk);
146 }
147 break;
148
149 case X25_STATE_1: /* T21 */
150 case X25_STATE_4: /* T22 */
151 x25_write_internal(sk, X25_CLEAR_REQUEST);
152 x25->state = X25_STATE_2;
153 x25_start_t23timer(sk);
154 break;
155
156 case X25_STATE_2: /* T23 */
157 x25_disconnect(sk, ETIMEDOUT, 0, 0);
158 break;
159 }
160}
161
162static void x25_timer_expiry(struct timer_list *t)
163{
164 struct x25_sock *x25 = from_timer(x25, t, timer);
165 struct sock *sk = &x25->sk;
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}