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 <linux/fcntl.h> 29 #include <linux/mm.h> 30 #include <linux/interrupt.h> 31 32 void ax25_std_heartbeat_expiry(ax25_cb *ax25) 33 { 34 struct sock *sk = ax25->sk; 35 36 if (sk) 37 bh_lock_sock(sk); 38 39 switch (ax25->state) { 40 case AX25_STATE_0: 41 /* Magic here: If we listen() and a new link dies before it 42 is accepted() it isn't 'dead' so doesn't get removed. */ 43 if (!sk || sock_flag(sk, SOCK_DESTROY) || 44 (sk->sk_state == TCP_LISTEN && 45 sock_flag(sk, SOCK_DEAD))) { 46 if (sk) { 47 sock_hold(sk); 48 ax25_destroy_socket(ax25); 49 bh_unlock_sock(sk); 50 sock_put(sk); 51 } else 52 ax25_destroy_socket(ax25); 53 return; 54 } 55 break; 56 57 case AX25_STATE_3: 58 case AX25_STATE_4: 59 /* 60 * Check the state of the receive buffer. 61 */ 62 if (sk != NULL) { 63 if (atomic_read(&sk->sk_rmem_alloc) < 64 (sk->sk_rcvbuf >> 1) && 65 (ax25->condition & AX25_COND_OWN_RX_BUSY)) { 66 ax25->condition &= ~AX25_COND_OWN_RX_BUSY; 67 ax25->condition &= ~AX25_COND_ACK_PENDING; 68 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE); 69 break; 70 } 71 } 72 } 73 74 if (sk) 75 bh_unlock_sock(sk); 76 77 ax25_start_heartbeat(ax25); 78 } 79 80 void ax25_std_t2timer_expiry(ax25_cb *ax25) 81 { 82 if (ax25->condition & AX25_COND_ACK_PENDING) { 83 ax25->condition &= ~AX25_COND_ACK_PENDING; 84 ax25_std_timeout_response(ax25); 85 } 86 } 87 88 void ax25_std_t3timer_expiry(ax25_cb *ax25) 89 { 90 ax25->n2count = 0; 91 ax25_std_transmit_enquiry(ax25); 92 ax25->state = AX25_STATE_4; 93 } 94 95 void ax25_std_idletimer_expiry(ax25_cb *ax25) 96 { 97 ax25_clear_queues(ax25); 98 99 ax25->n2count = 0; 100 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 101 ax25->state = AX25_STATE_2; 102 103 ax25_calculate_t1(ax25); 104 ax25_start_t1timer(ax25); 105 ax25_stop_t2timer(ax25); 106 ax25_stop_t3timer(ax25); 107 108 if (ax25->sk != NULL) { 109 bh_lock_sock(ax25->sk); 110 ax25->sk->sk_state = TCP_CLOSE; 111 ax25->sk->sk_err = 0; 112 ax25->sk->sk_shutdown |= SEND_SHUTDOWN; 113 if (!sock_flag(ax25->sk, SOCK_DEAD)) { 114 ax25->sk->sk_state_change(ax25->sk); 115 sock_set_flag(ax25->sk, SOCK_DEAD); 116 } 117 bh_unlock_sock(ax25->sk); 118 } 119 } 120 121 void ax25_std_t1timer_expiry(ax25_cb *ax25) 122 { 123 switch (ax25->state) { 124 case AX25_STATE_1: 125 if (ax25->n2count == ax25->n2) { 126 if (ax25->modulus == AX25_MODULUS) { 127 ax25_disconnect(ax25, ETIMEDOUT); 128 return; 129 } else { 130 ax25->modulus = AX25_MODULUS; 131 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; 132 ax25->n2count = 0; 133 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); 134 } 135 } else { 136 ax25->n2count++; 137 if (ax25->modulus == AX25_MODULUS) 138 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); 139 else 140 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND); 141 } 142 break; 143 144 case AX25_STATE_2: 145 if (ax25->n2count == ax25->n2) { 146 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 147 ax25_disconnect(ax25, ETIMEDOUT); 148 return; 149 } else { 150 ax25->n2count++; 151 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 152 } 153 break; 154 155 case AX25_STATE_3: 156 ax25->n2count = 1; 157 ax25_std_transmit_enquiry(ax25); 158 ax25->state = AX25_STATE_4; 159 break; 160 161 case AX25_STATE_4: 162 if (ax25->n2count == ax25->n2) { 163 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); 164 ax25_disconnect(ax25, ETIMEDOUT); 165 return; 166 } else { 167 ax25->n2count++; 168 ax25_std_transmit_enquiry(ax25); 169 } 170 break; 171 } 172 173 ax25_calculate_t1(ax25); 174 ax25_start_t1timer(ax25); 175 } 176