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/* $KTH: resolve.c,v 1.12 1997/10/28 15:37:39 bg Exp $ */
/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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.
*
* 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.
*
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 "krb_locl.h"
#include "resolve.h"
#define DECL(X) {#X, T_##X}
static struct stot{
char *name;
int type;
}stot[] = {
DECL(A),
DECL(NS),
DECL(CNAME),
DECL(PTR),
DECL(MX),
DECL(TXT),
DECL(AFSDB),
DECL(SRV),
{NULL, 0}
};
static int
string_to_type(const char *name)
{
struct stot *p = stot;
for(p = stot; p->name; p++)
if(strcasecmp(name, p->name) == 0)
return p->type;
return -1;
}
#if 0
static char *
type_to_string(int type)
{
struct stot *p = stot;
for(p = stot; p->name; p++)
if(type == p->type)
return p->name;
return NULL;
}
#endif
void
dns_free_data(struct dns_reply *r)
{
struct resource_record *rr;
if(r->q.domain)
free(r->q.domain);
for(rr = r->head; rr;){
struct resource_record *tmp = rr;
if(rr->domain)
free(rr->domain);
if(rr->u.data)
free(rr->u.data);
rr = rr->next;
free(tmp);
}
free (r);
}
static struct dns_reply*
parse_reply(unsigned char *data, int len)
{
unsigned char *p;
char host[128];
int status;
struct dns_reply *r;
struct resource_record **rr;
r = (struct dns_reply*)malloc(sizeof(struct dns_reply));
memset(r, 0, sizeof(struct dns_reply));
p = data;
memcpy(&r->h, p, sizeof(HEADER));
p += sizeof(HEADER);
status = dn_expand(data, data + len, p, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
r->q.domain = strdup(host);
p += status;
r->q.type = (p[0] << 8 | p[1]);
p += 2;
r->q.class = (p[0] << 8 | p[1]);
p += 2;
rr = &r->head;
while(p < data + len){
int type, class, ttl, size;
status = dn_expand(data, data + len, p, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
p += status;
type = (p[0] << 8) | p[1];
p += 2;
class = (p[0] << 8) | p[1];
p += 2;
ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
p += 4;
size = (p[0] << 8) | p[1];
p += 2;
*rr = (struct resource_record*)calloc(1,
sizeof(struct resource_record));
(*rr)->domain = strdup(host);
(*rr)->type = type;
(*rr)->class = class;
(*rr)->ttl = ttl;
(*rr)->size = size;
switch(type){
case T_NS:
case T_CNAME:
case T_PTR:
status = dn_expand(data, data + len, p, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
(*rr)->u.txt = strdup(host);
break;
case T_MX:
case T_AFSDB:{
status = dn_expand(data, data + len, p + 2, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
(*rr)->u.mx = (struct mx_record*)malloc(sizeof(struct mx_record) +
strlen(host));
(*rr)->u.mx->preference = (p[0] << 8) | p[1];
strcpy((*rr)->u.mx->domain, host);
break;
}
case T_SRV:{
status = dn_expand(data, data + len, p + 6, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
(*rr)->u.srv =
(struct srv_record*)malloc(sizeof(struct srv_record) +
strlen(host));
(*rr)->u.srv->priority = (p[0] << 8) | p[1];
(*rr)->u.srv->weight = (p[2] << 8) | p[3];
(*rr)->u.srv->port = (p[4] << 8) | p[5];
strcpy((*rr)->u.srv->target, host);
break;
}
case T_TXT:{
(*rr)->u.txt = (char*)malloc(size + 1);
strncpy((*rr)->u.txt, (char*)p + 1, *p);
(*rr)->u.txt[*p] = 0;
break;
}
default:
(*rr)->u.data = (unsigned char*)malloc(size);
memcpy((*rr)->u.data, p, size);
}
p += size;
rr = &(*rr)->next;
}
*rr = NULL;
return r;
}
struct dns_reply *
dns_lookup(const char *domain, const char *type_name)
{
unsigned char reply[1024];
int len;
int type;
struct dns_reply *r = NULL;
u_long old_options;
type = string_to_type(type_name);
if (krb_dns_debug) {
old_options = _res.options;
_res.options |= RES_DEBUG;
krb_warning("dns_lookup(%s, %s)\n", domain, type_name);
}
len = res_search(domain, C_IN, type, reply, sizeof(reply));
if (krb_dns_debug) {
_res.options = old_options;
krb_warning("dns_lookup(%s, %s) --> %d\n", domain, type_name, len);
}
if (len >= 0)
r = parse_reply(reply, len);
return r;
}
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