136 lines
3.4 KiB
C
136 lines
3.4 KiB
C
/*-
|
|
* Copyright (c) 2012 Baptiste Daroussin <bapt@FreeBSD.org>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer,
|
|
* without modification, immediately at the beginning of the file.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <netinet/in.h>
|
|
#include <resolv.h>
|
|
|
|
#include "dns_utils.h"
|
|
|
|
typedef union {
|
|
HEADER hdr;
|
|
unsigned char buf[1024];
|
|
} dns_query;
|
|
|
|
struct dns_srvinfo *
|
|
dns_getsrvinfo(const char *zone)
|
|
{
|
|
struct dns_srvinfo **res, *first;
|
|
unsigned char *end, *p;
|
|
char host[MAXHOSTNAMELEN];
|
|
dns_query q;
|
|
int len, qdcount, ancount, n, i;
|
|
unsigned int type, class, ttl, priority, weight, port;
|
|
|
|
if ((len = res_query(zone, C_IN, T_SRV, q.buf, sizeof(q.buf))) == -1 ||
|
|
len < (int)sizeof(HEADER))
|
|
return (NULL);
|
|
|
|
qdcount = ntohs(q.hdr.qdcount);
|
|
ancount = ntohs(q.hdr.ancount);
|
|
|
|
end = q.buf + len;
|
|
p = q.buf + sizeof(HEADER);
|
|
|
|
while(qdcount > 0 && p < end) {
|
|
qdcount--;
|
|
if((len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN)) < 0)
|
|
return (NULL);
|
|
p += len + NS_QFIXEDSZ;
|
|
}
|
|
|
|
res = calloc(ancount, sizeof(struct dns_srvinfo *));
|
|
if (res == NULL)
|
|
return (NULL);
|
|
|
|
n = 0;
|
|
while (ancount > 0 && p < end) {
|
|
ancount--;
|
|
len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN);
|
|
if (len < 0) {
|
|
for (i = 0; i < n; i++)
|
|
free(res[i]);
|
|
free(res);
|
|
return NULL;
|
|
}
|
|
|
|
p += len;
|
|
|
|
NS_GET16(type, p);
|
|
NS_GET16(class, p);
|
|
NS_GET32(ttl, p);
|
|
NS_GET16(len, p);
|
|
|
|
if (type != T_SRV) {
|
|
p += len;
|
|
continue;
|
|
}
|
|
|
|
NS_GET16(priority, p);
|
|
NS_GET16(weight, p);
|
|
NS_GET16(port, p);
|
|
|
|
len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN);
|
|
if (len < 0) {
|
|
for (i = 0; i < n; i++)
|
|
free(res[i]);
|
|
free(res);
|
|
return (NULL);
|
|
}
|
|
|
|
res[n] = malloc(sizeof(struct dns_srvinfo));
|
|
if (res[n] == NULL) {
|
|
for (i = 0; i < n; i++)
|
|
free(res[i]);
|
|
free(res);
|
|
return (NULL);
|
|
}
|
|
res[n]->type = type;
|
|
res[n]->class = class;
|
|
res[n]->ttl = ttl;
|
|
res[n]->priority = priority;
|
|
res[n]->weight = weight;
|
|
res[n]->port = port;
|
|
res[n]->next = NULL;
|
|
strlcpy(res[n]->host, host, MAXHOSTNAMELEN);
|
|
|
|
p += len;
|
|
n++;
|
|
}
|
|
|
|
for (i = 0; i < n - 1; i++)
|
|
res[i]->next = res[i + 1];
|
|
|
|
first = res[0];
|
|
free(res);
|
|
|
|
return (first);
|
|
}
|