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 x25_destroy_socket(sk); 118 goto unlock; 119 } 120 break; 121 122 case X25_STATE_3: 123 /* 124 * Check for the state of the receive buffer. 125 */ 126 x25_check_rbuf(sk); 127 break; 128 } 129 restart_heartbeat: 130 x25_start_heartbeat(sk); 131 unlock: 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 } 177