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) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 8 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) 9 */ 10 #include <linux/errno.h> 11 #include <linux/types.h> 12 #include <linux/socket.h> 13 #include <linux/spinlock.h> 14 #include <linux/in.h> 15 #include <linux/kernel.h> 16 #include <linux/jiffies.h> 17 #include <linux/timer.h> 18 #include <linux/string.h> 19 #include <linux/sockios.h> 20 #include <linux/net.h> 21 #include <net/tcp_states.h> 22 #include <net/ax25.h> 23 #include <linux/inet.h> 24 #include <linux/netdevice.h> 25 #include <linux/skbuff.h> 26 #include <net/sock.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 static void ax25_ds_timeout(unsigned long); 34 35 /* 36 * Add DAMA slave timeout timer to timer list. 37 * Unlike the connection based timers the timeout function gets 38 * triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT 39 * (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in 40 * 1/10th of a second. 41 */ 42 43 void ax25_ds_setup_timer(ax25_dev *ax25_dev) 44 { 45 setup_timer(&ax25_dev->dama.slave_timer, ax25_ds_timeout, 46 (unsigned long)ax25_dev); 47 } 48 49 void ax25_ds_del_timer(ax25_dev *ax25_dev) 50 { 51 if (ax25_dev) 52 del_timer(&ax25_dev->dama.slave_timer); 53 } 54 55 void ax25_ds_set_timer(ax25_dev *ax25_dev) 56 { 57 if (ax25_dev == NULL) /* paranoia */ 58 return; 59 60 ax25_dev->dama.slave_timeout = 61 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10; 62 mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ); 63 } 64 65 /* 66 * DAMA Slave Timeout 67 * Silently discard all (slave) connections in case our master forgot us... 68 */ 69 70 static void ax25_ds_timeout(unsigned long arg) 71 { 72 ax25_dev *ax25_dev = (struct ax25_dev *) arg; 73 ax25_cb *ax25; 74 struct hlist_node *node; 75 76 if (ax25_dev == NULL || !ax25_dev->dama.slave) 77 return; /* Yikes! */ 78 79 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) { 80 ax25_ds_set_timer(ax25_dev); 81 return; 82 } 83 84 spin_lock(&ax25_list_lock); 85 ax25_for_each(ax25, node, &ax25_list) { 86 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE)) 87 continue; 88 89 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 90 ax25_disconnect(ax25, ETIMEDOUT); 91 } 92 spin_unlock(&ax25_list_lock); 93 94 ax25_dev_dama_off(ax25_dev); 95 } 96 97 void ax25_ds_heartbeat_expiry(ax25_cb *ax25) 98 { 99 struct sock *sk=ax25->sk; 100 101 if (sk) 102 bh_lock_sock(sk); 103 104 switch (ax25->state) { 105 106 case AX25_STATE_0: 107 /* Magic here: If we listen() and a new link dies before it 108 is accepted() it isn't 'dead' so doesn't get removed. */ 109 if (!sk || sock_flag(sk, SOCK_DESTROY) || 110 (sk->sk_state == TCP_LISTEN && 111 sock_flag(sk, SOCK_DEAD))) { 112 if (sk) { 113 sock_hold(sk); 114 ax25_destroy_socket(ax25); 115 sock_put(sk); 116 bh_unlock_sock(sk); 117 } else 118 ax25_destroy_socket(ax25); 119 return; 120 } 121 break; 122 123 case AX25_STATE_3: 124 /* 125 * Check the state of the receive buffer. 126 */ 127 if (sk != NULL) { 128 if (atomic_read(&sk->sk_rmem_alloc) < 129 (sk->sk_rcvbuf >> 1) && 130 (ax25->condition & AX25_COND_OWN_RX_BUSY)) { 131 ax25->condition &= ~AX25_COND_OWN_RX_BUSY; 132 ax25->condition &= ~AX25_COND_ACK_PENDING; 133 break; 134 } 135 } 136 break; 137 } 138 139 if (sk) 140 bh_unlock_sock(sk); 141 142 ax25_start_heartbeat(ax25); 143 } 144 145 /* dl1bke 960114: T3 works much like the IDLE timeout, but 146 * gets reloaded with every frame for this 147 * connection. 148 */ 149 void ax25_ds_t3timer_expiry(ax25_cb *ax25) 150 { 151 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 152 ax25_dama_off(ax25); 153 ax25_disconnect(ax25, ETIMEDOUT); 154 } 155 156 /* dl1bke 960228: close the connection when IDLE expires. 157 * unlike T3 this timer gets reloaded only on 158 * I frames. 159 */ 160 void ax25_ds_idletimer_expiry(ax25_cb *ax25) 161 { 162 ax25_clear_queues(ax25); 163 164 ax25->n2count = 0; 165 ax25->state = AX25_STATE_2; 166 167 ax25_calculate_t1(ax25); 168 ax25_start_t1timer(ax25); 169 ax25_stop_t3timer(ax25); 170 171 if (ax25->sk != NULL) { 172 bh_lock_sock(ax25->sk); 173 ax25->sk->sk_state = TCP_CLOSE; 174 ax25->sk->sk_err = 0; 175 ax25->sk->sk_shutdown |= SEND_SHUTDOWN; 176 if (!sock_flag(ax25->sk, SOCK_DEAD)) { 177 ax25->sk->sk_state_change(ax25->sk); 178 sock_set_flag(ax25->sk, SOCK_DEAD); 179 } 180 bh_unlock_sock(ax25->sk); 181 } 182 } 183 184 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC 185 * within the poll of any connected channel. Remember 186 * that we are not allowed to send anything unless we 187 * get polled by the Master. 188 * 189 * Thus we'll have to do parts of our T1 handling in 190 * ax25_enquiry_response(). 191 */ 192 void ax25_ds_t1_timeout(ax25_cb *ax25) 193 { 194 switch (ax25->state) { 195 case AX25_STATE_1: 196 if (ax25->n2count == ax25->n2) { 197 if (ax25->modulus == AX25_MODULUS) { 198 ax25_disconnect(ax25, ETIMEDOUT); 199 return; 200 } else { 201 ax25->modulus = AX25_MODULUS; 202 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; 203 ax25->n2count = 0; 204 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 205 } 206 } else { 207 ax25->n2count++; 208 if (ax25->modulus == AX25_MODULUS) 209 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 210 else 211 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND); 212 } 213 break; 214 215 case AX25_STATE_2: 216 if (ax25->n2count == ax25->n2) { 217 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 218 ax25_disconnect(ax25, ETIMEDOUT); 219 return; 220 } else { 221 ax25->n2count++; 222 } 223 break; 224 225 case AX25_STATE_3: 226 if (ax25->n2count == ax25->n2) { 227 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); 228 ax25_disconnect(ax25, ETIMEDOUT); 229 return; 230 } else { 231 ax25->n2count++; 232 } 233 break; 234 } 235 236 ax25_calculate_t1(ax25); 237 ax25_start_t1timer(ax25); 238 } 239