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(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