/*	$OpenBSD: dname.c,v 1.4 2011/04/02 15:59:17 eric Exp $	*/
/*
 * Copyright (c) 2009,2010	Eric Faurot	<eric@faurot.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include "dnsutil.h"

size_t
dname_len(const char *dname)
{
	size_t	l;

	l = 0;

	while(dname[l])
		l += dname[l] + 1;

	return l;
}

size_t
dname_depth(const char *dname)
{
	size_t	l;

	l = 0;

	while(*dname) {
		l += 1;
		dname += *dname + 1;
	}

	return l;
}

const char*
dname_up(const char *dname, unsigned int n)
{
	while(n--) {
		if (dname[0] == '\0')
			return (NULL);
		dname += *dname + 1;
	}
	return (dname);
}


int
dname_is_in(const char *dname, const char *domain)
{
	size_t	l, ld;

	l = dname_depth(dname);
	ld = dname_depth(domain);

	if (ld > l)
		return (0);

	dname = dname_up(dname, l - ld);

	if (strcasecmp(dname, domain) == 0)
		return (1);

	return (0);
}

int
dname_is_reverse(const char *dname)
{
	static int	init = 0;
	static char	arpa[15];

	if (init == 0) {
		init = 1;
		dname_from_fqdn("in-addr.arpa.", arpa, sizeof arpa);
	}

	return (dname_is_in(dname, arpa));
}

int
dname_is_wildcard(const char *dname)
{
	return (dname[0] == 1 && dname[1] == '*');
}

int
dname_check_label(const char *s, size_t l)
{
	if (l == 0 || l > 63)
		return (-1);

	for(l--; l; l--, s++)
		if (!(isalnum(*s) || *s == '_' || *s == '-'))
			return (-1);

	return (0);
}

ssize_t
dname_from_fqdn(const char *str, char *dst, size_t max)
{
	ssize_t	 res;
	size_t	 l, n;
	char	*d;

	res = 0;

	/* special case: the root domain */
	if (str[0] == '.') {
		if (str[1] != '\0')
			return (-1);
		if (dst && max >= 1)
			*dst = '\0';
		return (1);
	}

	for(; *str; str = d + 1) {

		d = strchr(str, '.');
		if (d == NULL || d == str)
			return (-1);

		l = (d - str);

		if (dname_check_label(str, l) == -1)
			return (-1);

		res += l + 1;

		if (dst) {
			*dst++ = l;
			max -= 1;
			n = (l > max) ? max : l;
			memmove(dst, str, n);
			max -= n;
			if (max == 0)
				dst = NULL;
			else
				dst += n;
		}
	}

	if (dst)
		*dst++ = '\0';

	return (res + 1);
}

ssize_t
dname_from_sockaddr(const struct sockaddr *sa, char *dst, size_t max)
{
	char	buf[80];

	if (sockaddr_as_fqdn(sa, buf, sizeof(buf)) == -1)
		return (-1);

	return dname_from_fqdn(buf, dst, max);
}