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/in.h> 14 #include <linux/kernel.h> 15 #include <linux/sched.h> 16 #include <linux/timer.h> 17 #include <linux/string.h> 18 #include <linux/sockios.h> 19 #include <linux/spinlock.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 <asm/uaccess.h> 27 #include <asm/system.h> 28 #include <linux/fcntl.h> 29 #include <linux/mm.h> 30 #include <linux/interrupt.h> 31 32 void ax25_ds_nr_error_recovery(ax25_cb *ax25) 33 { 34 ax25_ds_establish_data_link(ax25); 35 } 36 37 /* 38 * dl1bke 960114: transmit I frames on DAMA poll 39 */ 40 void ax25_ds_enquiry_response(ax25_cb *ax25) 41 { 42 ax25_cb *ax25o; 43 struct hlist_node *node; 44 45 /* Please note that neither DK4EG�s nor DG2FEF�s 46 * DAMA spec mention the following behaviour as seen 47 * with TheFirmware: 48 * 49 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 50 * DL1BKE->DB0ACH <I NR=0 NS=0> 51 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 52 * DL1BKE->DB0ACH <RR R F R0> 53 * 54 * The Flexnet DAMA Master implementation apparently 55 * insists on the "proper" AX.25 behaviour: 56 * 57 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 58 * DL1BKE->DB0ACH <RR R F R0> 59 * DL1BKE->DB0ACH <I NR=0 NS=0> 60 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 61 * 62 * Flexnet refuses to send us *any* I frame if we send 63 * a REJ in case AX25_COND_REJECT is set. It is superfluous in 64 * this mode anyway (a RR or RNR invokes the retransmission). 65 * Is this a Flexnet bug? 66 */ 67 68 ax25_std_enquiry_response(ax25); 69 70 if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) { 71 ax25_requeue_frames(ax25); 72 ax25_kick(ax25); 73 } 74 75 if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL) 76 ax25_ds_t1_timeout(ax25); 77 else 78 ax25->n2count = 0; 79 80 ax25_start_t3timer(ax25); 81 ax25_ds_set_timer(ax25->ax25_dev); 82 83 spin_lock_bh(&ax25_list_lock); 84 ax25_for_each(ax25o, node, &ax25_list) { 85 if (ax25o == ax25) 86 continue; 87 88 if (ax25o->ax25_dev != ax25->ax25_dev) 89 continue; 90 91 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) { 92 ax25_ds_t1_timeout(ax25o); 93 continue; 94 } 95 96 if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) { 97 ax25_requeue_frames(ax25o); 98 ax25_kick(ax25o); 99 } 100 101 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL) 102 ax25_ds_t1_timeout(ax25o); 103 104 /* do not start T3 for listening sockets (tnx DD8NE) */ 105 106 if (ax25o->state != AX25_STATE_0) 107 ax25_start_t3timer(ax25o); 108 } 109 spin_unlock_bh(&ax25_list_lock); 110 } 111 112 void ax25_ds_establish_data_link(ax25_cb *ax25) 113 { 114 ax25->condition &= AX25_COND_DAMA_MODE; 115 ax25->n2count = 0; 116 ax25_calculate_t1(ax25); 117 ax25_start_t1timer(ax25); 118 ax25_stop_t2timer(ax25); 119 ax25_start_t3timer(ax25); 120 } 121 122 /* 123 * :::FIXME::: 124 * This is a kludge. Not all drivers recognize kiss commands. 125 * We need a driver level request to switch duplex mode, that does 126 * either SCC changing, PI config or KISS as required. Currently 127 * this request isn't reliable. 128 */ 129 static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param) 130 { 131 struct sk_buff *skb; 132 unsigned char *p; 133 134 if (ax25_dev->dev == NULL) 135 return; 136 137 if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL) 138 return; 139 140 skb->nh.raw = skb->data; 141 p = skb_put(skb, 2); 142 143 *p++ = cmd; 144 *p++ = param; 145 146 skb->protocol = ax25_type_trans(skb, ax25_dev->dev); 147 148 dev_queue_xmit(skb); 149 } 150 151 /* 152 * A nasty problem arises if we count the number of DAMA connections 153 * wrong, especially when connections on the device already existed 154 * and our network node (or the sysop) decides to turn on DAMA Master 155 * mode. We thus flag the 'real' slave connections with 156 * ax25->dama_slave=1 and look on every disconnect if still slave 157 * connections exist. 158 */ 159 static int ax25_check_dama_slave(ax25_dev *ax25_dev) 160 { 161 ax25_cb *ax25; 162 int res = 0; 163 struct hlist_node *node; 164 165 spin_lock_bh(&ax25_list_lock); 166 ax25_for_each(ax25, node, &ax25_list) 167 if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) { 168 res = 1; 169 break; 170 } 171 spin_unlock_bh(&ax25_list_lock); 172 173 return res; 174 } 175 176 static void ax25_dev_dama_on(ax25_dev *ax25_dev) 177 { 178 if (ax25_dev == NULL) 179 return; 180 181 if (ax25_dev->dama.slave == 0) 182 ax25_kiss_cmd(ax25_dev, 5, 1); 183 184 ax25_dev->dama.slave = 1; 185 ax25_ds_set_timer(ax25_dev); 186 } 187 188 void ax25_dev_dama_off(ax25_dev *ax25_dev) 189 { 190 if (ax25_dev == NULL) 191 return; 192 193 if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) { 194 ax25_kiss_cmd(ax25_dev, 5, 0); 195 ax25_dev->dama.slave = 0; 196 ax25_ds_del_timer(ax25_dev); 197 } 198 } 199 200 void ax25_dama_on(ax25_cb *ax25) 201 { 202 ax25_dev_dama_on(ax25->ax25_dev); 203 ax25->condition |= AX25_COND_DAMA_MODE; 204 } 205 206 void ax25_dama_off(ax25_cb *ax25) 207 { 208 ax25->condition &= ~AX25_COND_DAMA_MODE; 209 ax25_dev_dama_off(ax25->ax25_dev); 210 } 211 212