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 <asm/system.h> 28#include <linux/fcntl.h> 29#include <linux/mm.h> 30#include <linux/interrupt.h> 31 32void 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 */ 40void 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(&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(&ax25_list_lock); 110} 111 112void 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 122static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param) 123{ 124 struct sk_buff *skb; 125 unsigned char *p; 126 127 if (ax25_dev->dev == NULL) 128 return; 129 130 if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL) 131 return; 132 133 skb_reset_network_header(skb); 134 p = skb_put(skb, 2); 135 136 *p++ = cmd; 137 *p++ = param; 138 139 skb->protocol = ax25_type_trans(skb, ax25_dev->dev); 140 141 dev_queue_xmit(skb); 142} 143 144/* 145 * A nasty problem arises if we count the number of DAMA connections 146 * wrong, especially when connections on the device already existed 147 * and our network node (or the sysop) decides to turn on DAMA Master 148 * mode. We thus flag the 'real' slave connections with 149 * ax25->dama_slave=1 and look on every disconnect if still slave 150 * connections exist. 151 */ 152static int ax25_check_dama_slave(ax25_dev *ax25_dev) 153{ 154 ax25_cb *ax25; 155 int res = 0; 156 struct hlist_node *node; 157 158 spin_lock(&ax25_list_lock); 159 ax25_for_each(ax25, node, &ax25_list) 160 if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) { 161 res = 1; 162 break; 163 } 164 spin_unlock(&ax25_list_lock); 165 166 return res; 167} 168 169static void ax25_dev_dama_on(ax25_dev *ax25_dev) 170{ 171 if (ax25_dev == NULL) 172 return; 173 174 if (ax25_dev->dama.slave == 0) 175 ax25_kiss_cmd(ax25_dev, 5, 1); 176 177 ax25_dev->dama.slave = 1; 178 ax25_ds_set_timer(ax25_dev); 179} 180 181void ax25_dev_dama_off(ax25_dev *ax25_dev) 182{ 183 if (ax25_dev == NULL) 184 return; 185 186 if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) { 187 ax25_kiss_cmd(ax25_dev, 5, 0); 188 ax25_dev->dama.slave = 0; 189 ax25_ds_del_timer(ax25_dev); 190 } 191} 192 193void ax25_dama_on(ax25_cb *ax25) 194{ 195 ax25_dev_dama_on(ax25->ax25_dev); 196 ax25->condition |= AX25_COND_DAMA_MODE; 197} 198 199void ax25_dama_off(ax25_cb *ax25) 200{ 201 ax25->condition &= ~AX25_COND_DAMA_MODE; 202 ax25_dev_dama_off(ax25->ax25_dev); 203} 204