1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License as published by 4 * the Free Software Foundation; either version 2 of the License, or 5 * (at your option) any later version. 6 * 7 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) 8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) 10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr) 11 */ 12 #include <linux/errno.h> 13 #include <linux/types.h> 14 #include <linux/socket.h> 15 #include <linux/in.h> 16 #include <linux/kernel.h> 17 #include <linux/timer.h> 18 #include <linux/string.h> 19 #include <linux/sockios.h> 20 #include <linux/net.h> 21 #include <net/ax25.h> 22 #include <linux/inet.h> 23 #include <linux/netdevice.h> 24 #include <linux/skbuff.h> 25 #include <net/sock.h> 26 #include <net/tcp_states.h> 27 #include <asm/uaccess.h> 28 #include <asm/system.h> 29 #include <linux/fcntl.h> 30 #include <linux/mm.h> 31 #include <linux/interrupt.h> 32 33 void ax25_std_heartbeat_expiry(ax25_cb *ax25) 34 { 35 struct sock *sk = ax25->sk; 36 37 if (sk) 38 bh_lock_sock(sk); 39 40 switch (ax25->state) { 41 case AX25_STATE_0: 42 /* Magic here: If we listen() and a new link dies before it 43 is accepted() it isn't 'dead' so doesn't get removed. */ 44 if (!sk || sock_flag(sk, SOCK_DESTROY) || 45 (sk->sk_state == TCP_LISTEN && 46 sock_flag(sk, SOCK_DEAD))) { 47 if (sk) { 48 sock_hold(sk); 49 ax25_destroy_socket(ax25); 50 bh_unlock_sock(sk); 51 sock_put(sk); 52 } else 53 ax25_destroy_socket(ax25); 54 return; 55 } 56 break; 57 58 case AX25_STATE_3: 59 case AX25_STATE_4: 60 /* 61 * Check the state of the receive buffer. 62 */ 63 if (sk != NULL) { 64 if (atomic_read(&sk->sk_rmem_alloc) < 65 (sk->sk_rcvbuf >> 1) && 66 (ax25->condition & AX25_COND_OWN_RX_BUSY)) { 67 ax25->condition &= ~AX25_COND_OWN_RX_BUSY; 68 ax25->condition &= ~AX25_COND_ACK_PENDING; 69 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE); 70 break; 71 } 72 } 73 } 74 75 if (sk) 76 bh_unlock_sock(sk); 77 78 ax25_start_heartbeat(ax25); 79 } 80 81 void ax25_std_t2timer_expiry(ax25_cb *ax25) 82 { 83 if (ax25->condition & AX25_COND_ACK_PENDING) { 84 ax25->condition &= ~AX25_COND_ACK_PENDING; 85 ax25_std_timeout_response(ax25); 86 } 87 } 88 89 void ax25_std_t3timer_expiry(ax25_cb *ax25) 90 { 91 ax25->n2count = 0; 92 ax25_std_transmit_enquiry(ax25); 93 ax25->state = AX25_STATE_4; 94 } 95 96 void ax25_std_idletimer_expiry(ax25_cb *ax25) 97 { 98 ax25_clear_queues(ax25); 99 100 ax25->n2count = 0; 101 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 102 ax25->state = AX25_STATE_2; 103 104 ax25_calculate_t1(ax25); 105 ax25_start_t1timer(ax25); 106 ax25_stop_t2timer(ax25); 107 ax25_stop_t3timer(ax25); 108 109 if (ax25->sk != NULL) { 110 bh_lock_sock(ax25->sk); 111 ax25->sk->sk_state = TCP_CLOSE; 112 ax25->sk->sk_err = 0; 113 ax25->sk->sk_shutdown |= SEND_SHUTDOWN; 114 if (!sock_flag(ax25->sk, SOCK_DEAD)) { 115 ax25->sk->sk_state_change(ax25->sk); 116 sock_set_flag(ax25->sk, SOCK_DEAD); 117 } 118 bh_unlock_sock(ax25->sk); 119 } 120 } 121 122 void ax25_std_t1timer_expiry(ax25_cb *ax25) 123 { 124 switch (ax25->state) { 125 case AX25_STATE_1: 126 if (ax25->n2count == ax25->n2) { 127 if (ax25->modulus == AX25_MODULUS) { 128 ax25_disconnect(ax25, ETIMEDOUT); 129 return; 130 } else { 131 ax25->modulus = AX25_MODULUS; 132 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; 133 ax25->n2count = 0; 134 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); 135 } 136 } else { 137 ax25->n2count++; 138 if (ax25->modulus == AX25_MODULUS) 139 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); 140 else 141 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND); 142 } 143 break; 144 145 case AX25_STATE_2: 146 if (ax25->n2count == ax25->n2) { 147 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 148 ax25_disconnect(ax25, ETIMEDOUT); 149 return; 150 } else { 151 ax25->n2count++; 152 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 153 } 154 break; 155 156 case AX25_STATE_3: 157 ax25->n2count = 1; 158 ax25_std_transmit_enquiry(ax25); 159 ax25->state = AX25_STATE_4; 160 break; 161 162 case AX25_STATE_4: 163 if (ax25->n2count == ax25->n2) { 164 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); 165 ax25_disconnect(ax25, ETIMEDOUT); 166 return; 167 } else { 168 ax25->n2count++; 169 ax25_std_transmit_enquiry(ax25); 170 } 171 break; 172 } 173 174 ax25_calculate_t1(ax25); 175 ax25_start_t1timer(ax25); 176 } 177