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/timer.h> 16 #include <linux/string.h> 17 #include <linux/sockios.h> 18 #include <linux/spinlock.h> 19 #include <linux/net.h> 20 #include <linux/gfp.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 <linux/fcntl.h> 28 #include <linux/mm.h> 29 #include <linux/interrupt.h> 30 31 void ax25_ds_nr_error_recovery(ax25_cb *ax25) 32 { 33 ax25_ds_establish_data_link(ax25); 34 } 35 36 /* 37 * dl1bke 960114: transmit I frames on DAMA poll 38 */ 39 void ax25_ds_enquiry_response(ax25_cb *ax25) 40 { 41 ax25_cb *ax25o; 42 43 /* Please note that neither DK4EG's nor DG2FEF's 44 * DAMA spec mention the following behaviour as seen 45 * with TheFirmware: 46 * 47 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 48 * DL1BKE->DB0ACH <I NR=0 NS=0> 49 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 50 * DL1BKE->DB0ACH <RR R F R0> 51 * 52 * The Flexnet DAMA Master implementation apparently 53 * insists on the "proper" AX.25 behaviour: 54 * 55 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 56 * DL1BKE->DB0ACH <RR R F R0> 57 * DL1BKE->DB0ACH <I NR=0 NS=0> 58 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 59 * 60 * Flexnet refuses to send us *any* I frame if we send 61 * a REJ in case AX25_COND_REJECT is set. It is superfluous in 62 * this mode anyway (a RR or RNR invokes the retransmission). 63 * Is this a Flexnet bug? 64 */ 65 66 ax25_std_enquiry_response(ax25); 67 68 if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) { 69 ax25_requeue_frames(ax25); 70 ax25_kick(ax25); 71 } 72 73 if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL) 74 ax25_ds_t1_timeout(ax25); 75 else 76 ax25->n2count = 0; 77 78 ax25_start_t3timer(ax25); 79 ax25_ds_set_timer(ax25->ax25_dev); 80 81 spin_lock(&ax25_list_lock); 82 ax25_for_each(ax25o, &ax25_list) { 83 if (ax25o == ax25) 84 continue; 85 86 if (ax25o->ax25_dev != ax25->ax25_dev) 87 continue; 88 89 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) { 90 ax25_ds_t1_timeout(ax25o); 91 continue; 92 } 93 94 if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) { 95 ax25_requeue_frames(ax25o); 96 ax25_kick(ax25o); 97 } 98 99 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL) 100 ax25_ds_t1_timeout(ax25o); 101 102 /* do not start T3 for listening sockets (tnx DD8NE) */ 103 104 if (ax25o->state != AX25_STATE_0) 105 ax25_start_t3timer(ax25o); 106 } 107 spin_unlock(&ax25_list_lock); 108 } 109 110 void ax25_ds_establish_data_link(ax25_cb *ax25) 111 { 112 ax25->condition &= AX25_COND_DAMA_MODE; 113 ax25->n2count = 0; 114 ax25_calculate_t1(ax25); 115 ax25_start_t1timer(ax25); 116 ax25_stop_t2timer(ax25); 117 ax25_start_t3timer(ax25); 118 } 119 120 /* 121 * :::FIXME::: 122 * This is a kludge. Not all drivers recognize kiss commands. 123 * We need a driver level request to switch duplex mode, that does 124 * either SCC changing, PI config or KISS as required. Currently 125 * this request isn't reliable. 126 */ 127 static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param) 128 { 129 struct sk_buff *skb; 130 unsigned char *p; 131 132 if (ax25_dev->dev == NULL) 133 return; 134 135 if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL) 136 return; 137 138 skb_reset_network_header(skb); 139 p = skb_put(skb, 2); 140 141 *p++ = cmd; 142 *p++ = param; 143 144 skb->protocol = ax25_type_trans(skb, ax25_dev->dev); 145 146 dev_queue_xmit(skb); 147 } 148 149 /* 150 * A nasty problem arises if we count the number of DAMA connections 151 * wrong, especially when connections on the device already existed 152 * and our network node (or the sysop) decides to turn on DAMA Master 153 * mode. We thus flag the 'real' slave connections with 154 * ax25->dama_slave=1 and look on every disconnect if still slave 155 * connections exist. 156 */ 157 static int ax25_check_dama_slave(ax25_dev *ax25_dev) 158 { 159 ax25_cb *ax25; 160 int res = 0; 161 162 spin_lock(&ax25_list_lock); 163 ax25_for_each(ax25, &ax25_list) 164 if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) { 165 res = 1; 166 break; 167 } 168 spin_unlock(&ax25_list_lock); 169 170 return res; 171 } 172 173 static void ax25_dev_dama_on(ax25_dev *ax25_dev) 174 { 175 if (ax25_dev == NULL) 176 return; 177 178 if (ax25_dev->dama.slave == 0) 179 ax25_kiss_cmd(ax25_dev, 5, 1); 180 181 ax25_dev->dama.slave = 1; 182 ax25_ds_set_timer(ax25_dev); 183 } 184 185 void ax25_dev_dama_off(ax25_dev *ax25_dev) 186 { 187 if (ax25_dev == NULL) 188 return; 189 190 if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) { 191 ax25_kiss_cmd(ax25_dev, 5, 0); 192 ax25_dev->dama.slave = 0; 193 ax25_ds_del_timer(ax25_dev); 194 } 195 } 196 197 void ax25_dama_on(ax25_cb *ax25) 198 { 199 ax25_dev_dama_on(ax25->ax25_dev); 200 ax25->condition |= AX25_COND_DAMA_MODE; 201 } 202 203 void ax25_dama_off(ax25_cb *ax25) 204 { 205 ax25->condition &= ~AX25_COND_DAMA_MODE; 206 ax25_dev_dama_off(ax25->ax25_dev); 207 } 208 209