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 = 65 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10; 66 ax25_ds_add_timer(ax25_dev); 67 } 68 69 /* 70 * DAMA Slave Timeout 71 * Silently discard all (slave) connections in case our master forgot us... 72 */ 73 74 static void ax25_ds_timeout(unsigned long arg) 75 { 76 ax25_dev *ax25_dev = (struct ax25_dev *) arg; 77 ax25_cb *ax25; 78 struct hlist_node *node; 79 80 if (ax25_dev == NULL || !ax25_dev->dama.slave) 81 return; /* Yikes! */ 82 83 if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) { 84 ax25_ds_set_timer(ax25_dev); 85 return; 86 } 87 88 spin_lock(&ax25_list_lock); 89 ax25_for_each(ax25, node, &ax25_list) { 90 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE)) 91 continue; 92 93 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 94 ax25_disconnect(ax25, ETIMEDOUT); 95 } 96 spin_unlock(&ax25_list_lock); 97 98 ax25_dev_dama_off(ax25_dev); 99 } 100 101 void ax25_ds_heartbeat_expiry(ax25_cb *ax25) 102 { 103 struct sock *sk=ax25->sk; 104 105 if (sk) 106 bh_lock_sock(sk); 107 108 switch (ax25->state) { 109 110 case AX25_STATE_0: 111 /* Magic here: If we listen() and a new link dies before it 112 is accepted() it isn't 'dead' so doesn't get removed. */ 113 if (!sk || sock_flag(sk, SOCK_DESTROY) || 114 (sk->sk_state == TCP_LISTEN && 115 sock_flag(sk, SOCK_DEAD))) { 116 if (sk) { 117 sock_hold(sk); 118 ax25_destroy_socket(ax25); 119 sock_put(sk); 120 bh_unlock_sock(sk); 121 } else 122 ax25_destroy_socket(ax25); 123 return; 124 } 125 break; 126 127 case AX25_STATE_3: 128 /* 129 * Check the state of the receive buffer. 130 */ 131 if (sk != NULL) { 132 if (atomic_read(&sk->sk_rmem_alloc) < 133 (sk->sk_rcvbuf / 2) && 134 (ax25->condition & AX25_COND_OWN_RX_BUSY)) { 135 ax25->condition &= ~AX25_COND_OWN_RX_BUSY; 136 ax25->condition &= ~AX25_COND_ACK_PENDING; 137 break; 138 } 139 } 140 break; 141 } 142 143 if (sk) 144 bh_unlock_sock(sk); 145 146 ax25_start_heartbeat(ax25); 147 } 148 149 /* dl1bke 960114: T3 works much like the IDLE timeout, but 150 * gets reloaded with every frame for this 151 * connection. 152 */ 153 void ax25_ds_t3timer_expiry(ax25_cb *ax25) 154 { 155 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 156 ax25_dama_off(ax25); 157 ax25_disconnect(ax25, ETIMEDOUT); 158 } 159 160 /* dl1bke 960228: close the connection when IDLE expires. 161 * unlike T3 this timer gets reloaded only on 162 * I frames. 163 */ 164 void ax25_ds_idletimer_expiry(ax25_cb *ax25) 165 { 166 ax25_clear_queues(ax25); 167 168 ax25->n2count = 0; 169 ax25->state = AX25_STATE_2; 170 171 ax25_calculate_t1(ax25); 172 ax25_start_t1timer(ax25); 173 ax25_stop_t3timer(ax25); 174 175 if (ax25->sk != NULL) { 176 bh_lock_sock(ax25->sk); 177 ax25->sk->sk_state = TCP_CLOSE; 178 ax25->sk->sk_err = 0; 179 ax25->sk->sk_shutdown |= SEND_SHUTDOWN; 180 if (!sock_flag(ax25->sk, SOCK_DEAD)) { 181 ax25->sk->sk_state_change(ax25->sk); 182 sock_set_flag(ax25->sk, SOCK_DEAD); 183 } 184 bh_unlock_sock(ax25->sk); 185 } 186 } 187 188 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC 189 * within the poll of any connected channel. Remember 190 * that we are not allowed to send anything unless we 191 * get polled by the Master. 192 * 193 * Thus we'll have to do parts of our T1 handling in 194 * ax25_enquiry_response(). 195 */ 196 void ax25_ds_t1_timeout(ax25_cb *ax25) 197 { 198 switch (ax25->state) { 199 case AX25_STATE_1: 200 if (ax25->n2count == ax25->n2) { 201 if (ax25->modulus == AX25_MODULUS) { 202 ax25_disconnect(ax25, ETIMEDOUT); 203 return; 204 } else { 205 ax25->modulus = AX25_MODULUS; 206 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; 207 ax25->n2count = 0; 208 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 209 } 210 } else { 211 ax25->n2count++; 212 if (ax25->modulus == AX25_MODULUS) 213 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND); 214 else 215 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND); 216 } 217 break; 218 219 case AX25_STATE_2: 220 if (ax25->n2count == ax25->n2) { 221 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); 222 ax25_disconnect(ax25, ETIMEDOUT); 223 return; 224 } else { 225 ax25->n2count++; 226 } 227 break; 228 229 case AX25_STATE_3: 230 if (ax25->n2count == ax25->n2) { 231 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); 232 ax25_disconnect(ax25, ETIMEDOUT); 233 return; 234 } else { 235 ax25->n2count++; 236 } 237 break; 238 } 239 240 ax25_calculate_t1(ax25); 241 ax25_start_t1timer(ax25); 242 } 243