[linux.git] / net / ax25 / ax25_addr.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Jonathan Naylor G4KLX ([email protected])
 */
#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;
		}
	}
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
1da177e4 LT	3	*
	4	* Copyright (C) Jonathan Naylor G4KLX ([email protected])
	5	*/
	6	#include <linux/errno.h>
	7	#include <linux/types.h>
	8	#include <linux/socket.h>
	9	#include <linux/in.h>
	10	#include <linux/kernel.h>
70868eac	11	#include <linux/module.h>
1da177e4 LT	12	#include <linux/timer.h>
	13	#include <linux/string.h>
	14	#include <linux/sockios.h>
	15	#include <linux/net.h>
	16	#include <net/ax25.h>
	17	#include <linux/inet.h>
	18	#include <linux/netdevice.h>
	19	#include <linux/skbuff.h>
	20	#include <net/sock.h>
7c0f6ba6	21	#include <linux/uaccess.h>
1da177e4 LT	22	#include <linux/fcntl.h>
	23	#include <linux/mm.h>
	24	#include <linux/interrupt.h>
	25
	26	/*
15b1c0e8 RB	27	* The default broadcast address of an interface is QST-0; the default address
	28	* is LINUX-1. The null address is defined as a callsign of all spaces with
	29	* an SSID of zero.
1da177e4	30	*/
1da177e4	31
15b1c0e8 RB	32	const ax25_address ax25_bcast =
	33	{{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
	34	const ax25_address ax25_defaddr =
	35	{{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}};
	36	const ax25_address null_ax25_address =
	37	{{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
	38
	39	EXPORT_SYMBOL_GPL(ax25_bcast);
	40	EXPORT_SYMBOL_GPL(ax25_defaddr);
70868eac RB	41	EXPORT_SYMBOL(null_ax25_address);
70868eac RB	42
1da177e4 LT	43	/*
	44	* ax25 -> ascii conversion
	45	*/
e8cc49bb	46	char ax2asc(char buf, const ax25_address *a)
1da177e4	47	{
1da177e4 LT	48	char c, *s;
	49	int n;
	50
	51	for (n = 0, s = buf; n < 6; n++) {
	52	c = (a->ax25_call[n] >> 1) & 0x7F;
	53
	54	if (c != ' ') *s++ = c;
	55	}
	56
	57	*s++ = '-';
	58
	59	if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
	60	*s++ = '1';
	61	n -= 10;
	62	}
	63
	64	*s++ = n + '0';
	65	*s++ = '\0';
	66
	67	if (buf == '\0' \|\| buf == '-')
	68	return "*";
	69
	70	return buf;
	71
	72	}
	73
70868eac RB	74	EXPORT_SYMBOL(ax2asc);
70868eac RB	75
1da177e4 LT	76	/*
	77	* ascii -> ax25 conversion
	78	*/
e8cc49bb	79	void asc2ax(ax25_address addr, const char callsign)
1da177e4	80	{
f654c854	81	const char *s;
1da177e4 LT	82	int n;
	83
	84	for (s = callsign, n = 0; n < 6; n++) {
	85	if (s != '\0' && s != '-')
baed16a7	86	addr->ax25_call[n] = *s++;
1da177e4	87	else
baed16a7 RB	88	addr->ax25_call[n] = ' ';
	89	addr->ax25_call[n] <<= 1;
	90	addr->ax25_call[n] &= 0xFE;
1da177e4 LT	91	}
	92
	93	if (*s++ == '\0') {
baed16a7 RB	94	addr->ax25_call[6] = 0x00;
baed16a7 RB	95	return;
1da177e4 LT	96	}
1da177e4 LT	97
baed16a7	98	addr->ax25_call[6] = *s++ - '0';
1da177e4 LT	99
1da177e4 LT	100	if (*s != '\0') {
baed16a7 RB	101	addr->ax25_call[6] *= 10;
baed16a7 RB	102	addr->ax25_call[6] += *s++ - '0';
1da177e4 LT	103	}
1da177e4 LT	104
baed16a7 RB	105	addr->ax25_call[6] <<= 1;
baed16a7 RB	106	addr->ax25_call[6] &= 0x1E;
1da177e4 LT	107	}
1da177e4 LT	108
70868eac RB	109	EXPORT_SYMBOL(asc2ax);
70868eac RB	110
1da177e4 LT	111	/*
	112	* Compare two ax.25 addresses
	113	*/
e8cc49bb	114	int ax25cmp(const ax25_address a, const ax25_address b)
1da177e4 LT	115	{
	116	int ct = 0;
	117
	118	while (ct < 6) {
	119	if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */
	120	return 1;
	121	ct++;
	122	}
	123
528930b9 YH	124	if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */
528930b9 YH	125	return 0;
1da177e4	126
528930b9	127	return 2; /* Partial match */
1da177e4 LT	128	}
1da177e4 LT	129
70868eac RB	130	EXPORT_SYMBOL(ax25cmp);
70868eac RB	131
1da177e4 LT	132	/*
	133	* Compare two AX.25 digipeater paths.
	134	*/
e8cc49bb	135	int ax25digicmp(const ax25_digi digi1, const ax25_digi digi2)
1da177e4 LT	136	{
	137	int i;
	138
	139	if (digi1->ndigi != digi2->ndigi)
	140	return 1;
	141
	142	if (digi1->lastrepeat != digi2->lastrepeat)
	143	return 1;
	144
	145	for (i = 0; i < digi1->ndigi; i++)
	146	if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0)
	147	return 1;
	148
	149	return 0;
	150	}
	151
	152	/*
	153	* Given an AX.25 address pull of to, from, digi list, command/response and the start of data
	154	*
	155	*/
e8cc49bb RB	156	const unsigned char ax25_addr_parse(const unsigned char buf, int len,
	157	ax25_address src, ax25_address dest, ax25_digi digi, int flags,
	158	int *dama)
1da177e4 LT	159	{
	160	int d = 0;
	161
	162	if (len < 14) return NULL;
	163
	164	if (flags != NULL) {
	165	*flags = 0;
	166
	167	if (buf[6] & AX25_CBIT)
	168	*flags = AX25_COMMAND;
	169	if (buf[13] & AX25_CBIT)
	170	*flags = AX25_RESPONSE;
	171	}
	172
	173	if (dama != NULL)
	174	*dama = ~buf[13] & AX25_DAMA_FLAG;
	175
	176	/* Copy to, from */
	177	if (dest != NULL)
	178	memcpy(dest, buf + 0, AX25_ADDR_LEN);
	179	if (src != NULL)
	180	memcpy(src, buf + 7, AX25_ADDR_LEN);
	181
	182	buf += 2 * AX25_ADDR_LEN;
	183	len -= 2 * AX25_ADDR_LEN;
	184
	185	digi->lastrepeat = -1;
	186	digi->ndigi = 0;
	187
	188	while (!(buf[-1] & AX25_EBIT)) {
5c9df5fe DC	189	if (d >= AX25_MAX_DIGIS)
	190	return NULL;
	191	if (len < AX25_ADDR_LEN)
	192	return NULL;
1da177e4 LT	193
	194	memcpy(&digi->calls[d], buf, AX25_ADDR_LEN);
	195	digi->ndigi = d + 1;
	196
	197	if (buf[6] & AX25_HBIT) {
	198	digi->repeated[d] = 1;
	199	digi->lastrepeat = d;
	200	} else {
	201	digi->repeated[d] = 0;
	202	}
	203
	204	buf += AX25_ADDR_LEN;
	205	len -= AX25_ADDR_LEN;
	206	d++;
	207	}
	208
	209	return buf;
	210	}
	211
	212	/*
	213	* Assemble an AX.25 header from the bits
	214	*/
e8cc49bb RB	215	int ax25_addr_build(unsigned char buf, const ax25_address src,
e8cc49bb RB	216	const ax25_address dest, const ax25_digi d, int flag, int modulus)
1da177e4 LT	217	{
	218	int len = 0;
	219	int ct = 0;
	220
	221	memcpy(buf, dest, AX25_ADDR_LEN);
	222	buf[6] &= ~(AX25_EBIT \| AX25_CBIT);
	223	buf[6] \|= AX25_SSSID_SPARE;
	224
	225	if (flag == AX25_COMMAND) buf[6] \|= AX25_CBIT;
	226
	227	buf += AX25_ADDR_LEN;
	228	len += AX25_ADDR_LEN;
	229
	230	memcpy(buf, src, AX25_ADDR_LEN);
	231	buf[6] &= ~(AX25_EBIT \| AX25_CBIT);
	232	buf[6] &= ~AX25_SSSID_SPARE;
	233
	234	if (modulus == AX25_MODULUS)
	235	buf[6] \|= AX25_SSSID_SPARE;
	236	else
	237	buf[6] \|= AX25_ESSID_SPARE;
	238
	239	if (flag == AX25_RESPONSE) buf[6] \|= AX25_CBIT;
	240
	241	/*
	242	* Fast path the normal digiless path
	243	*/
	244	if (d == NULL \|\| d->ndigi == 0) {
	245	buf[6] \|= AX25_EBIT;
	246	return 2 * AX25_ADDR_LEN;
	247	}
	248
	249	buf += AX25_ADDR_LEN;
	250	len += AX25_ADDR_LEN;
	251
	252	while (ct < d->ndigi) {
	253	memcpy(buf, &d->calls[ct], AX25_ADDR_LEN);
	254
	255	if (d->repeated[ct])
	256	buf[6] \|= AX25_HBIT;
	257	else
	258	buf[6] &= ~AX25_HBIT;
	259
	260	buf[6] &= ~AX25_EBIT;
	261	buf[6] \|= AX25_SSSID_SPARE;
	262
	263	buf += AX25_ADDR_LEN;
	264	len += AX25_ADDR_LEN;
	265	ct++;
	266	}
	267
	268	buf[-1] \|= AX25_EBIT;
	269
	270	return len;
	271	}
	272
e8cc49bb	273	int ax25_addr_size(const ax25_digi *dp)
1da177e4 LT	274	{
	275	if (dp == NULL)
	276	return 2 * AX25_ADDR_LEN;
	277
	278	return AX25_ADDR_LEN * (2 + dp->ndigi);
	279	}
	280
	281	/*
	282	* Reverse Digipeat List. May not pass both parameters as same struct
	283	*/
e8cc49bb	284	void ax25_digi_invert(const ax25_digi in, ax25_digi out)
1da177e4 LT	285	{
	286	int ct;
	287
	288	out->ndigi = in->ndigi;
	289	out->lastrepeat = in->ndigi - in->lastrepeat - 2;
	290
	291	/* Invert the digipeaters */
	292	for (ct = 0; ct < in->ndigi; ct++) {
	293	out->calls[ct] = in->calls[in->ndigi - ct - 1];
	294
	295	if (ct <= out->lastrepeat) {
	296	out->calls[ct].ax25_call[6] \|= AX25_HBIT;
	297	out->repeated[ct] = 1;
	298	} else {
	299	out->calls[ct].ax25_call[6] &= ~AX25_HBIT;
	300	out->repeated[ct] = 0;
	301	}
	302	}
	303	}