1 /*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine, randomly fail to work with new
5 * releases, misbehave and/or generally screw up. It might even work.
6 *
7 * This code REQUIRES 2.1.15 or higher
8 *
9 * This module:
10 * This module is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * History
16 * X.25 001 Jonathan Naylor Started coding.
17 * X.25 002 Jonathan Naylor New timer architecture.
18 * Centralised disconnection processing.
19 */
20
21 #include <linux/errno.h>
22 #include <linux/types.h>
23 #include <linux/socket.h>
24 #include <linux/in.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/timer.h>
28 #include <linux/string.h>
29 #include <linux/sockios.h>
30 #include <linux/net.h>
31 #include <linux/inet.h>
32 #include <linux/netdevice.h>
33 #include <linux/skbuff.h>
34 #include <net/sock.h>
35 #include <asm/segment.h>
36 #include <asm/system.h>
37 #include <linux/fcntl.h>
38 #include <linux/mm.h>
39 #include <linux/interrupt.h>
40 #include <net/x25.h>
41
42 static void x25_heartbeat_expiry(unsigned long);
43 static void x25_timer_expiry(unsigned long);
44
x25_start_heartbeat(struct sock * sk)45 void x25_start_heartbeat(struct sock *sk)
46 {
47 del_timer(&sk->timer);
48
49 sk->timer.data = (unsigned long)sk;
50 sk->timer.function = &x25_heartbeat_expiry;
51 sk->timer.expires = jiffies + 5 * HZ;
52
53 add_timer(&sk->timer);
54 }
55
x25_stop_heartbeat(struct sock * sk)56 void x25_stop_heartbeat(struct sock *sk)
57 {
58 del_timer(&sk->timer);
59 }
60
x25_start_t2timer(struct sock * sk)61 void x25_start_t2timer(struct sock *sk)
62 {
63 del_timer(&sk->protinfo.x25->timer);
64
65 sk->protinfo.x25->timer.data = (unsigned long)sk;
66 sk->protinfo.x25->timer.function = &x25_timer_expiry;
67 sk->protinfo.x25->timer.expires = jiffies + sk->protinfo.x25->t2;
68
69 add_timer(&sk->protinfo.x25->timer);
70 }
71
x25_start_t21timer(struct sock * sk)72 void x25_start_t21timer(struct sock *sk)
73 {
74 del_timer(&sk->protinfo.x25->timer);
75
76 sk->protinfo.x25->timer.data = (unsigned long)sk;
77 sk->protinfo.x25->timer.function = &x25_timer_expiry;
78 sk->protinfo.x25->timer.expires = jiffies + sk->protinfo.x25->t21;
79
80 add_timer(&sk->protinfo.x25->timer);
81 }
82
x25_start_t22timer(struct sock * sk)83 void x25_start_t22timer(struct sock *sk)
84 {
85 del_timer(&sk->protinfo.x25->timer);
86
87 sk->protinfo.x25->timer.data = (unsigned long)sk;
88 sk->protinfo.x25->timer.function = &x25_timer_expiry;
89 sk->protinfo.x25->timer.expires = jiffies + sk->protinfo.x25->t22;
90
91 add_timer(&sk->protinfo.x25->timer);
92 }
93
x25_start_t23timer(struct sock * sk)94 void x25_start_t23timer(struct sock *sk)
95 {
96 del_timer(&sk->protinfo.x25->timer);
97
98 sk->protinfo.x25->timer.data = (unsigned long)sk;
99 sk->protinfo.x25->timer.function = &x25_timer_expiry;
100 sk->protinfo.x25->timer.expires = jiffies + sk->protinfo.x25->t23;
101
102 add_timer(&sk->protinfo.x25->timer);
103 }
104
x25_stop_timer(struct sock * sk)105 void x25_stop_timer(struct sock *sk)
106 {
107 del_timer(&sk->protinfo.x25->timer);
108 }
109
x25_display_timer(struct sock * sk)110 unsigned long x25_display_timer(struct sock *sk)
111 {
112 if (!timer_pending(&sk->protinfo.x25->timer))
113 return 0;
114
115 return sk->protinfo.x25->timer.expires - jiffies;
116 }
117
x25_heartbeat_expiry(unsigned long param)118 static void x25_heartbeat_expiry(unsigned long param)
119 {
120 struct sock *sk = (struct sock *)param;
121
122 bh_lock_sock(sk);
123 if (sk->lock.users) { /* can currently only occur in state 3 */
124 goto restart_heartbeat;
125 }
126
127 switch (sk->protinfo.x25->state) {
128
129 case X25_STATE_0:
130 /* Magic here: If we listen() and a new link dies before it
131 is accepted() it isn't 'dead' so doesn't get removed. */
132 if (sk->destroy || (sk->state == TCP_LISTEN && sk->dead)) {
133 x25_destroy_socket(sk);
134 goto unlock;
135 }
136 break;
137
138 case X25_STATE_3:
139 /*
140 * Check for the state of the receive buffer.
141 */
142 x25_check_rbuf(sk);
143 break;
144 }
145 restart_heartbeat:
146 x25_start_heartbeat(sk);
147 unlock:
148 bh_unlock_sock(sk);
149 }
150
151 /*
152 * Timer has expired, it may have been T2, T21, T22, or T23. We can tell
153 * by the state machine state.
154 */
x25_do_timer_expiry(struct sock * sk)155 static inline void x25_do_timer_expiry(struct sock * sk)
156 {
157 switch (sk->protinfo.x25->state) {
158
159 case X25_STATE_3: /* T2 */
160 if (sk->protinfo.x25->condition & X25_COND_ACK_PENDING) {
161 sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;
162 x25_enquiry_response(sk);
163 }
164 break;
165
166 case X25_STATE_1: /* T21 */
167 case X25_STATE_4: /* T22 */
168 x25_write_internal(sk, X25_CLEAR_REQUEST);
169 sk->protinfo.x25->state = X25_STATE_2;
170 x25_start_t23timer(sk);
171 break;
172
173 case X25_STATE_2: /* T23 */
174 x25_disconnect(sk, ETIMEDOUT, 0, 0);
175 break;
176 }
177 }
178
x25_timer_expiry(unsigned long param)179 static void x25_timer_expiry(unsigned long param)
180 {
181 struct sock *sk = (struct sock *)param;
182
183 bh_lock_sock(sk);
184 if (sk->lock.users) { /* can currently only occur in state 3 */
185 if (sk->protinfo.x25->state == X25_STATE_3) {
186 x25_start_t2timer(sk);
187 }
188 } else {
189 x25_do_timer_expiry(sk);
190 }
191 bh_unlock_sock(sk);
192 }
193