1 files changed, 303 insertions, 0 deletions
diff --git a/net/ax25/ax25_addr.c b/net/ax25/ax25_addr.c
new file mode 100644
index 000000000..f68865a4d
--- /dev/null
+++ b/net/ax25/ax25_addr.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.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 <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ * The default broadcast address of an interface is QST-0; the default address
+ * is LINUX-1.  The null address is defined as a callsign of all spaces with
+ * an SSID of zero.
+ */
+
+const ax25_address ax25_bcast =
+	{{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
+const ax25_address ax25_defaddr =
+	{{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}};
+const ax25_address null_ax25_address =
+	{{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
+
+EXPORT_SYMBOL_GPL(ax25_bcast);
+EXPORT_SYMBOL_GPL(ax25_defaddr);
+EXPORT_SYMBOL(null_ax25_address);
+
+/*
+ *	ax25 -> ascii conversion
+ */
+char *ax2asc(char *buf, const ax25_address *a)
+{
+	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;
+
+}
+
+EXPORT_SYMBOL(ax2asc);
+
+/*
+ *	ascii -> ax25 conversion
+ */
+void asc2ax(ax25_address *addr, const char *callsign)
+{
+	const 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->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;
+}
+
+EXPORT_SYMBOL(asc2ax);
+
+/*
+ *	Compare two ax.25 addresses
+ */
+int ax25cmp(const ax25_address *a, const 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 */
+}
+
+EXPORT_SYMBOL(ax25cmp);
+
+/*
+ *	Compare two AX.25 digipeater paths.
+ */
+int ax25digicmp(const ax25_digi *digi1, const 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
+ *
+ */
+const unsigned char *ax25_addr_parse(const 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;
+		if (len < AX25_ADDR_LEN)
+			return 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, const ax25_address *src,
+	const ax25_address *dest, const 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(const 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(const ax25_digi *in, ax25_digi *out)
+{
+	int ct;
+
+	out->ndigi      = in->ndigi;
+	out->lastrepeat = in->ndigi - in->lastrepeat - 2;
+
+	/* Invert the digipeaters */
+	for (ct = 0; ct < in->ndigi; ct++) {
+		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;
+		}
+	}
+}