patch-2.1.30 linux/net/ax25/ax25_ds_subr.c

• Lines: 226
• Date: Thu Mar 20 18:17:13 1997
• Orig file: v2.1.29/linux/net/ax25/ax25_ds_subr.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.29/linux/net/ax25/ax25_ds_subr.c linux/net/ax25/ax25_ds_subr.c
@@ -0,0 +1,225 @@
+/*
+ *	AX.25 release 036
+ *
+ *	This is ALPHA test software. This code may break your machine, randomly fail to work with new 
+ *	releases, misbehave and/or generally screw up. It might even work. 
+ *
+ *	This code REQUIRES 2.1.15 or higher/ NET3.038
+ *
+ *	This module:
+ *		This module is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ *	Most of this code is based on the SDL diagrams published in the 7th
+ *	ARRL Computer Networking Conference papers. The diagrams have mistakes
+ *	in them, but are mostly correct. Before you modify the code could you
+ *	read the SDL diagrams as the code is not obvious and probably very
+ *	easy to break;
+ *
+ *	History
+ *	AX.25 036	Jonathan(G4KLX)	Cloned from ax25_out.c and ax25_subr.c.
+ *			Joerg(DL1BKE)	Changed ax25_ds_enquiry_response(),
+ *					fixed ax25_dama_on() and ax25_dama_off().
+ */
+
+#include <linux/config.h>
+#if defined(CONFIG_AX25_DAMA_SLAVE)
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+void ax25_ds_nr_error_recovery(ax25_cb *ax25)
+{
+	ax25_ds_establish_data_link(ax25);
+}
+
+/*
+ *	dl1bke 960114: transmit I frames on DAMA poll
+ */
+void ax25_ds_enquiry_response(ax25_cb *ax25)
+{
+	ax25_cb *ax25o;
+
+	/* Please note that neither DK4EG´s nor DG2FEF´s
+	 * DAMA spec mention the following behaviour as seen
+	 * with TheFirmware:
+	 *
+	 * 	DB0ACH->DL1BKE <RR C P R0> [DAMA]
+	 *	DL1BKE->DB0ACH <I NR=0 NS=0>
+	 *	DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+	 *	DL1BKE->DB0ACH <RR R F R0>
+	 *
+	 * The Flexnet DAMA Master implementation apparently
+	 * insists on the "proper" AX.25 behaviour:
+	 *
+	 * 	DB0ACH->DL1BKE <RR C P R0> [DAMA]
+	 *	DL1BKE->DB0ACH <RR R F R0>
+	 *	DL1BKE->DB0ACH <I NR=0 NS=0>
+	 *	DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+	 *
+	 * Flexnet refuses to send us *any* I frame if we send
+	 * a REJ in case AX25_COND_REJECT is set. It is superfluous in 
+	 * this mode anyway (a RR or RNR invokes the retransmission).
+	 * Is this a Flexnet bug?
+	 */
+
+	ax25_std_enquiry_response(ax25);
+
+	if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) {
+		ax25_requeue_frames(ax25);
+		ax25_kick(ax25);
+	}
+
+	if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL)
+		ax25_ds_t1_timeout(ax25);
+	else
+		ax25->n2count = 0;
+
+	ax25->t3timer = ax25->t3;
+	ax25_ds_set_timer(ax25->ax25_dev);
+
+	for (ax25o = ax25_list; ax25o != NULL; ax25o = ax25o->next) {
+		if (ax25o == ax25)
+			continue;
+
+		if (ax25o->ax25_dev != ax25->ax25_dev)
+			continue;
+
+		if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) {
+			ax25_ds_t1_timeout(ax25o);
+			continue;
+		}
+
+		if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && 
+		    (ax25o->state == AX25_STATE_3 || 
+		    (ax25o->state == AX25_STATE_4 && ax25o->t1timer == 0))) {
+			ax25_requeue_frames(ax25o);
+			ax25_kick(ax25o);
+		}
+
+		if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL)
+			ax25_ds_t1_timeout(ax25o);
+
+		ax25o->t3timer = ax25o->t3;
+	}
+}
+
+void ax25_ds_establish_data_link(ax25_cb *ax25)
+{
+	ax25->condition = 0x00;
+	ax25->n2count   = 0;
+
+	ax25->t3timer = ax25->t3;
+	ax25->t2timer = 0;
+	ax25->t1timer = ax25->t1 = ax25_calculate_t1(ax25);
+}
+
+/*
+ *	:::FIXME:::
+ *	This is a kludge. Not all drivers recognize kiss commands. 
+ *	We need a driver level  request to switch duplex mode, that does 
+ *	either SCC changing, PI config or KISS as required. Currently
+ *	this request isn't reliable.
+ *
+ */
+static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param)
+{
+	struct sk_buff *skb;
+	unsigned char *p;
+
+	if (ax25_dev->dev == NULL)
+		return;
+
+	if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL)
+		return;
+
+	p = skb_put(skb, 2);
+
+	*p++ = cmd;
+	*p++ = param;
+
+	skb->arp      = 1;
+	skb->dev      = ax25_dev->dev;
+	skb->priority = SOPRI_NORMAL;
+	skb->protocol = htons(ETH_P_AX25);
+
+	dev_queue_xmit(skb);
+}
+
+/*
+ *	A nasty problem arises if we count the number of DAMA connections
+ *	wrong, especially when connections on the device already existed
+ *	and our network node (or the sysop) decides to turn on DAMA Master
+ *	mode. We thus flag the 'real' slave connections with 
+ *	ax25->dama_slave=1 and look on every disconnect if still slave
+ *	connections exist.
+ */
+
+static int ax25_check_dama_slave(ax25_dev *ax25_dev)
+{
+	ax25_cb *ax25;
+
+	for (ax25 = ax25_list; ax25 != NULL ; ax25 = ax25->next)
+		if (ax25->ax25_dev == ax25_dev && ax25->dama_slave && ax25->state > AX25_STATE_1)
+			return 1;
+
+	return 0;
+}
+
+void ax25_dev_dama_on(ax25_dev *ax25_dev)
+{
+	if (ax25_dev == NULL)
+		return;
+
+	if (ax25_dev->dama.slave == 0)
+		ax25_kiss_cmd(ax25_dev, 5, 1);
+
+	ax25_dev->dama.slave = 1;
+	ax25_ds_set_timer(ax25_dev);
+}
+
+void ax25_dev_dama_off(ax25_dev *ax25_dev)
+{
+	if (ax25_dev == NULL)
+		return;
+
+	if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev))
+	{
+		ax25_kiss_cmd(ax25_dev, 5, 0);
+		ax25_dev->dama.slave = 0;
+		ax25_ds_del_timer(ax25_dev);
+	}
+}
+
+void ax25_dama_on(ax25_cb *ax25)
+{
+	ax25_dev_dama_on(ax25->ax25_dev);
+	ax25->dama_slave = 1;
+}
+
+void ax25_dama_off(ax25_cb *ax25)
+{
+	ax25_dev_dama_off(ax25->ax25_dev);
+	ax25->dama_slave = 0;
+}
+
+#endif