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(struct timer_list *t); 30 static void x25_timer_expiry(struct timer_list *t); 31 32 void 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 42 void x25_start_heartbeat(struct sock *sk) 43 { 44 mod_timer(&sk->sk_timer, jiffies + 5 * HZ); 45 } 46 47 void x25_stop_heartbeat(struct sock *sk) 48 { 49 del_timer(&sk->sk_timer); 50 } 51 52 void 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 59 void 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 66 void 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 73 void 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 80 void x25_stop_timer(struct sock *sk) 81 { 82 del_timer(&x25_sk(sk)->timer); 83 } 84 85 unsigned 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 95 static 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 } 127 restart_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 */ 136 static 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 } 161 162 static 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 } 175