patch-2.1.27 linux/net/ax25/ax25_addr.c

• Lines: 312
• Date: Tue Feb 25 17:12:51 1997
• Orig file: v2.1.26/linux/net/ax25/ax25_addr.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.26/linux/net/ax25/ax25_addr.c linux/net/ax25/ax25_addr.c
@@ -0,0 +1,311 @@
+/*
+ *	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)	Split from ax25_subr.c.
+ */
+
+#include <linux/config.h>
+#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
+#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>
+
+/*
+ *	The null address is defined as a callsign of all spaces with an
+ *	SSID of zero.
+ */
+ax25_address null_ax25_address = {{0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x00}};
+
+/*
+ *	ax25 -> ascii conversion
+ */
+char *ax2asc(ax25_address *a)
+{
+	static char buf[11];
+	char c, *s;
+	int n;
+
+	for (n = 0, s = buf; n < 6; n++) {
+		c = (a->ax25_call[n] >> 1) & 0x7F;
+
+		if (c != ' ') *s++ = c;
+	}
+
+	*s++ = '-';
+
+	if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
+		*s++ = '1';
+		n -= 10;
+	}
+
+	*s++ = n + '0';
+	*s++ = '\0';
+
+	if (*buf == '\0' || *buf == '-')
+	   return "*";
+
+	return buf;
+
+}
+
+/*
+ *	ascii -> ax25 conversion
+ */
+ax25_address *asc2ax(char *callsign)
+{
+	static ax25_address addr;
+	char *s;
+	int n;
+
+	for (s = callsign, n = 0; n < 6; n++) {
+		if (*s != '\0' && *s != '-')
+			addr.ax25_call[n] = *s++;
+		else
+			addr.ax25_call[n] = ' ';
+		addr.ax25_call[n] <<= 1;
+		addr.ax25_call[n] &= 0xFE;
+	}
+
+	if (*s++ == '\0') {
+		addr.ax25_call[6] = 0x00;
+		return &addr;
+	}
+
+	addr.ax25_call[6] = *s++ - '0';
+
+	if (*s != '\0') {
+		addr.ax25_call[6] *= 10;
+		addr.ax25_call[6] += *s++ - '0';
+	}
+
+	addr.ax25_call[6] <<= 1;
+	addr.ax25_call[6] &= 0x1E;
+
+	return &addr;
+}
+
+/*
+ *	Compare two ax.25 addresses
+ */
+int ax25cmp(ax25_address *a, ax25_address *b)
+{
+	int ct = 0;
+
+	while (ct < 6) {
+		if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE))	/* Clean off repeater bits */
+			return 1;
+		ct++;
+	}
+
+ 	if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E))	/* SSID without control bit */
+ 		return 0;
+
+ 	return 2;			/* Partial match */
+}
+
+/*
+ *	Compare two AX.25 digipeater paths.
+ */
+int ax25digicmp(ax25_digi *digi1, ax25_digi *digi2)
+{
+	int i;
+
+	if (digi1->ndigi != digi2->ndigi)
+		return 1;
+
+	if (digi1->lastrepeat != digi2->lastrepeat)
+		return 1;
+
+	for (i = 0; i < digi1->ndigi; i++)
+		if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0)
+			return 1;
+
+	return 0;
+}
+
+/*
+ *	Given an AX.25 address pull of to, from, digi list, command/response and the start of data
+ *
+ */
+unsigned char *ax25_addr_parse(unsigned char *buf, int len, ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags, int *dama)
+{
+	int d = 0;
+
+	if (len < 14) return NULL;
+
+	if (flags != NULL) {
+		*flags = 0;
+
+		if (buf[6] & AX25_CBIT)
+			*flags = AX25_COMMAND;
+		if (buf[13] & AX25_CBIT)
+			*flags = AX25_RESPONSE;
+	}
+
+	if (dama != NULL) 
+		*dama = ~buf[13] & AX25_DAMA_FLAG;
+
+	/* Copy to, from */
+	if (dest != NULL) 
+		memcpy(dest, buf + 0, AX25_ADDR_LEN);
+
+	if (src != NULL)  
+		memcpy(src,  buf + 7, AX25_ADDR_LEN);
+
+	buf += 2 * AX25_ADDR_LEN;
+	len -= 2 * AX25_ADDR_LEN;
+	digi->lastrepeat = -1;
+	digi->ndigi      = 0;
+
+	while (!(buf[-1] & AX25_EBIT)) {
+		if (d >= AX25_MAX_DIGIS)  return NULL;	/* Max of 6 digis */
+		if (len < 7) return NULL;	/* Short packet */
+
+		if (digi != NULL) {
+			memcpy(&digi->calls[d], buf, AX25_ADDR_LEN);
+			digi->ndigi = d + 1;
+			if (buf[6] & AX25_HBIT) {
+				digi->repeated[d] = 1;
+				digi->lastrepeat  = d;
+			} else {
+				digi->repeated[d] = 0;
+			}
+		}
+
+		buf += AX25_ADDR_LEN;
+		len -= AX25_ADDR_LEN;
+		d++;
+	}
+
+	return buf;
+}
+
+/*
+ *	Assemble an AX.25 header from the bits
+ */
+int ax25_addr_build(unsigned char *buf, ax25_address *src, ax25_address *dest, ax25_digi *d, int flag, int modulus)
+{
+	int len = 0;
+	int ct  = 0;
+
+	memcpy(buf, dest, AX25_ADDR_LEN);
+	buf[6] &= ~(AX25_EBIT | AX25_CBIT);
+	buf[6] |= AX25_SSSID_SPARE;
+
+	if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT;
+
+	buf += AX25_ADDR_LEN;
+	len += AX25_ADDR_LEN;
+
+	memcpy(buf, src, AX25_ADDR_LEN);
+	buf[6] &= ~(AX25_EBIT | AX25_CBIT);
+	buf[6] &= ~AX25_SSSID_SPARE;
+
+	if (modulus == AX25_MODULUS)
+		buf[6] |= AX25_SSSID_SPARE;
+	else
+		buf[6] |= AX25_ESSID_SPARE;
+
+	if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT;
+
+	/*
+	 *	Fast path the normal digiless path
+	 */
+	if (d == NULL || d->ndigi == 0) {
+		buf[6] |= AX25_EBIT;
+		return 2 * AX25_ADDR_LEN;
+	}	
+
+	buf += AX25_ADDR_LEN;
+	len += AX25_ADDR_LEN;
+
+	while (ct < d->ndigi) {
+		memcpy(buf, &d->calls[ct], AX25_ADDR_LEN);
+
+		if (d->repeated[ct])
+			buf[6] |= AX25_HBIT;
+		else
+			buf[6] &= ~AX25_HBIT;
+
+		buf[6] &= ~AX25_EBIT;
+		buf[6] |= AX25_SSSID_SPARE;
+
+		buf += AX25_ADDR_LEN;
+		len += AX25_ADDR_LEN;
+		ct++;
+	}
+
+	buf[-1] |= AX25_EBIT;
+
+	return len;
+}
+
+int ax25_addr_size(ax25_digi *dp)
+{
+	if (dp == NULL)
+		return 2 * AX25_ADDR_LEN;
+
+	return AX25_ADDR_LEN * (2 + dp->ndigi);
+}
+
+/* 
+ *	Reverse Digipeat List. May not pass both parameters as same struct
+ */
+void ax25_digi_invert(ax25_digi *in, ax25_digi *out)
+{
+	int ct = 0;
+
+	out->ndigi      = in->ndigi;
+	out->lastrepeat = in->ndigi - in->lastrepeat - 2;
+
+	/* Invert the digipeaters */
+
+	while (ct < in->ndigi) {
+		out->calls[ct]    = in->calls[in->ndigi - ct - 1];
+		if (ct <= out->lastrepeat) {
+			out->calls[ct].ax25_call[6] |= AX25_HBIT;
+			out->repeated[ct]            = 1;
+		} else {
+			out->calls[ct].ax25_call[6] &= ~AX25_HBIT;
+			out->repeated[ct]            = 0;
+		}
+		ct++;
+	}
+}
+
+#endif