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 <net/ax25.h> 21 #include <linux/inet.h> 22 #include <linux/netdevice.h> 23 #include <linux/skbuff.h> 24 #include <net/sock.h> 25 #include <asm/uaccess.h> 26 #include <asm/system.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 struct hlist_node *node; 43 44 /* Please note that neither DK4EG's nor DG2FEF's 45 * DAMA spec mention the following behaviour as seen 46 * with TheFirmware: 47 * 48 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 49 * DL1BKE->DB0ACH <I NR=0 NS=0> 50 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 51 * DL1BKE->DB0ACH <RR R F R0> 52 * 53 * The Flexnet DAMA Master implementation apparently 54 * insists on the "proper" AX.25 behaviour: 55 * 56 * DB0ACH->DL1BKE <RR C P R0> [DAMA] 57 * DL1BKE->DB0ACH <RR R F R0> 58 * DL1BKE->DB0ACH <I NR=0 NS=0> 59 * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> 60 * 61 * Flexnet refuses to send us *any* I frame if we send 62 * a REJ in case AX25_COND_REJECT is set. It is superfluous in 63 * this mode anyway (a RR or RNR invokes the retransmission). 64 * Is this a Flexnet bug? 65 */ 66 67 ax25_std_enquiry_response(ax25); 68 69 if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) { 70 ax25_requeue_frames(ax25); 71 ax25_kick(ax25); 72 } 73 74 if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL) 75 ax25_ds_t1_timeout(ax25); 76 else 77 ax25->n2count = 0; 78 79 ax25_start_t3timer(ax25); 80 ax25_ds_set_timer(ax25->ax25_dev); 81 82 spin_lock(&ax25_list_lock); 83 ax25_for_each(ax25o, node, &ax25_list) { 84 if (ax25o == ax25) 85 continue; 86 87 if (ax25o->ax25_dev != ax25->ax25_dev) 88 continue; 89 90 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) { 91 ax25_ds_t1_timeout(ax25o); 92 continue; 93 } 94 95 if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) { 96 ax25_requeue_frames(ax25o); 97 ax25_kick(ax25o); 98 } 99 100 if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL) 101 ax25_ds_t1_timeout(ax25o); 102 103 /* do not start T3 for listening sockets (tnx DD8NE) */ 104 105 if (ax25o->state != AX25_STATE_0) 106 ax25_start_t3timer(ax25o); 107 } 108 spin_unlock(&ax25_list_lock); 109 } 110 111 void ax25_ds_establish_data_link(ax25_cb *ax25) 112 { 113 ax25->condition &= AX25_COND_DAMA_MODE; 114 ax25->n2count = 0; 115 ax25_calculate_t1(ax25); 116 ax25_start_t1timer(ax25); 117 ax25_stop_t2timer(ax25); 118 ax25_start_t3timer(ax25); 119 } 120 121 /* 122 * :::FIXME::: 123 * This is a kludge. Not all drivers recognize kiss commands. 124 * We need a driver level request to switch duplex mode, that does 125 * either SCC changing, PI config or KISS as required. Currently 126 * this request isn't reliable. 127 */ 128 static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param) 129 { 130 struct sk_buff *skb; 131 unsigned char *p; 132 133 if (ax25_dev->dev == NULL) 134 return; 135 136 if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL) 137 return; 138 139 skb_reset_network_header(skb); 140 p = skb_put(skb, 2); 141 142 *p++ = cmd; 143 *p++ = param; 144 145 skb->protocol = ax25_type_trans(skb, ax25_dev->dev); 146 147 dev_queue_xmit(skb); 148 } 149 150 /* 151 * A nasty problem arises if we count the number of DAMA connections 152 * wrong, especially when connections on the device already existed 153 * and our network node (or the sysop) decides to turn on DAMA Master 154 * mode. We thus flag the 'real' slave connections with 155 * ax25->dama_slave=1 and look on every disconnect if still slave 156 * connections exist. 157 */ 158 static int ax25_check_dama_slave(ax25_dev *ax25_dev) 159 { 160 ax25_cb *ax25; 161 int res = 0; 162 struct hlist_node *node; 163 164 spin_lock(&ax25_list_lock); 165 ax25_for_each(ax25, node, &ax25_list) 166 if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) { 167 res = 1; 168 break; 169 } 170 spin_unlock(&ax25_list_lock); 171 172 return res; 173 } 174 175 static void ax25_dev_dama_on(ax25_dev *ax25_dev) 176 { 177 if (ax25_dev == NULL) 178 return; 179 180 if (ax25_dev->dama.slave == 0) 181 ax25_kiss_cmd(ax25_dev, 5, 1); 182 183 ax25_dev->dama.slave = 1; 184 ax25_ds_set_timer(ax25_dev); 185 } 186 187 void ax25_dev_dama_off(ax25_dev *ax25_dev) 188 { 189 if (ax25_dev == NULL) 190 return; 191 192 if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) { 193 ax25_kiss_cmd(ax25_dev, 5, 0); 194 ax25_dev->dama.slave = 0; 195 ax25_ds_del_timer(ax25_dev); 196 } 197 } 198 199 void ax25_dama_on(ax25_cb *ax25) 200 { 201 ax25_dev_dama_on(ax25->ax25_dev); 202 ax25->condition |= AX25_COND_DAMA_MODE; 203 } 204 205 void ax25_dama_off(ax25_cb *ax25) 206 { 207 ax25->condition &= ~AX25_COND_DAMA_MODE; 208 ax25_dev_dama_off(ax25->ax25_dev); 209 } 210 211