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 static void ax25_ds_add_timer(ax25_dev *ax25_dev) 44 { 45 struct timer_list *t = &ax25_dev->dama.slave_timer; 46 t->data = (unsigned long) ax25_dev; 47 t->function = &ax25_ds_timeout; 48 t->expires = jiffies + HZ; 49 add_timer(t); 50 } 51 52 void ax25_ds_del_timer(ax25_dev *ax25_dev) 53 { 54 if (ax25_dev) 55 del_timer(&ax25_dev->dama.slave_timer); 56 } 57 58 void ax25_ds_set_timer(ax25_dev *ax25_dev) 59 { 60 if (ax25_dev == NULL) /* paranoia */ 61 return; 62 63 del_timer(&ax25_dev->dama.slave_timer); 64 ax25_dev->dama.slave_timeout = ax25_dev->values[AX25_VALUES_DS_TIMEOUT] / 10; 65 ax25_ds_add_timer(ax25_dev); 66 } 67 68 /* 69 * DAMA Slave Timeout 70 * Silently discard all (slave) connections in case our master forgot us... 71 */ 72 73 static void ax25_ds_timeout(unsigned long arg) 74 { 75 ax25_dev *ax25_dev = (struct ax25_dev *) arg; 76 ax25_cb *ax25; 77 struct hlist_node *node; 78 79 if (ax25_dev == NULL || !ax25_dev->dama.slave) 80 return; /* Yikes! */ 81 82 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) { 83 ax25_ds_set_timer(ax25_dev); 84 return; 85 } 86 87 spin_lock_bh(&ax25_list_lock); 88 ax25_for_each(ax25, node, &ax25_list) { 89 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE)) 90 continue; 91 92 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 93 ax25_disconnect(ax25, ETIMEDOUT); 94 } 95 spin_unlock_bh(&ax25_list_lock); 96 97 ax25_dev_dama_off(ax25_dev); 98 } 99 100 void ax25_ds_heartbeat_expiry(ax25_cb *ax25) 101 { 102 struct sock *sk=ax25->sk; 103 104 if (sk) 105 bh_lock_sock(sk); 106 107 switch (ax25->state) { 108 109 case AX25_STATE_0: 110 /* Magic here: If we listen() and a new link dies before it 111 is accepted() it isn't 'dead' so doesn't get removed. */ 112 if (!sk || sock_flag(sk, SOCK_DESTROY) || 113 (sk->sk_state == TCP_LISTEN && 114 sock_flag(sk, SOCK_DEAD))) { 115 if (sk) { 116 sock_hold(sk); 117 ax25_destroy_socket(ax25); 118 sock_put(sk); 119 bh_unlock_sock(sk); 120 } else 121 ax25_destroy_socket(ax25); 122 return; 123 } 124 break; 125 126 case AX25_STATE_3: 127 /* 128 * Check the state of the receive buffer. 129 */ 130 if (sk != NULL) { 131 if (atomic_read(&sk->sk_rmem_alloc) < 132 (sk->sk_rcvbuf / 2) && 133 (ax25->condition & AX25_COND_OWN_RX_BUSY)) { 134 ax25->condition &= ~AX25_COND_OWN_RX_BUSY; 135 ax25->condition &= ~AX25_COND_ACK_PENDING; 136 break; 137 } 138 } 139 break; 140 } 141 142 if (sk) 143 bh_unlock_sock(sk); 144 145 ax25_start_heartbeat(ax25); 146 } 147 148 /* dl1bke 960114: T3 works much like the IDLE timeout, but 149 * gets reloaded with every frame for this 150 * connection. 151 */ 152 void ax25_ds_t3timer_expiry(ax25_cb *ax25) 153 { 154 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 155 ax25_dama_off(ax25); 156 ax25_disconnect(ax25, ETIMEDOUT); 157 } 158 159 /* dl1bke 960228: close the connection when IDLE expires. 160 * unlike T3 this timer gets reloaded only on 161 * I frames. 162 */ 163 void ax25_ds_idletimer_expiry(ax25_cb *ax25) 164 { 165 ax25_clear_queues(ax25); 166 167 ax25->n2count = 0; 168 ax25->state = AX25_STATE_2; 169 170 ax25_calculate_t1(ax25); 171 ax25_start_t1timer(ax25); 172 ax25_stop_t3timer(ax25); 173 174 if (ax25->sk != NULL) { 175 bh_lock_sock(ax25->sk); 176 ax25->sk->sk_state = TCP_CLOSE; 177 ax25->sk->sk_err = 0; 178 ax25->sk->sk_shutdown |= SEND_SHUTDOWN; 179 if (!sock_flag(ax25->sk, SOCK_DEAD)) { 180 ax25->sk->sk_state_change(ax25->sk); 181 sock_set_flag(ax25->sk, SOCK_DEAD); 182 } 183 bh_unlock_sock(ax25->sk); 184 } 185 } 186 187 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC 188 * within the poll of any connected channel. Remember 189 * that we are not allowed to send anything unless we 190 * get polled by the Master. 191 * 192 * Thus we'll have to do parts of our T1 handling in 193 * ax25_enquiry_response(). 194 */ 195 void ax25_ds_t1_timeout(ax25_cb *ax25) 196 { 197 switch (ax25->state) { 198 case AX25_STATE_1: 199 if (ax25->n2count == ax25->n2) { 200 if (ax25->modulus == AX25_MODULUS) { 201 ax25_disconnect(ax25, ETIMEDOUT); 202 return; 203 } else { 204 ax25->modulus = AX25_MODULUS; 205 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; 206 ax25->n2count = 0; 207 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 208 } 209 } else { 210 ax25->n2count++; 211 if (ax25->modulus == AX25_MODULUS) 212 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 213 else 214 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND); 215 } 216 break; 217 218 case AX25_STATE_2: 219 if (ax25->n2count == ax25->n2) { 220 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 221 ax25_disconnect(ax25, ETIMEDOUT); 222 return; 223 } else { 224 ax25->n2count++; 225 } 226 break; 227 228 case AX25_STATE_3: 229 if (ax25->n2count == ax25->n2) { 230 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); 231 ax25_disconnect(ax25, ETIMEDOUT); 232 return; 233 } else { 234 ax25->n2count++; 235 } 236 break; 237 } 238 239 ax25_calculate_t1(ax25); 240 ax25_start_t1timer(ax25); 241 } 242