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/*
** Copyright (C) 2006 Olivier DEMBOUR
** $Id: dns_decode.c,v 1.7.4.4 2010/02/11 15:05:49 collignon Exp $
**
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with This program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdio.h>
#include <arpa/inet.h>
#include "packet.h"
#include "dns.h"
#include "server.h"
#include "myerror.h"
#include "mystrnlen.h"
#include "log.h"
#include "debug.h"
#include "server.h"
#include "requests.h"
extern const t_command dns_commands[];
/*
Strip dot and domain name
extract the dns command
request is always ended by NULL
*/
static int dns_strip_dot_and_domain(t_conf *conf, t_request *req, char *output)
{
char *ptr;
char *ptr2;
unsigned int i=0, j, len;
int req_len, domain_len;
req_len = strlen(output);
domain_len = strlen(conf->my_domain);
ptr = strstr(output + (req_len - domain_len), conf->my_domain);
if (!ptr)
{
// FIXME bug ipv6 support ?
LOG("Query from %u.%u.%u.%u for unknown domain %s",
#ifndef WORDS_BIGENDIAN
(unsigned int) ((req->sa.sin_addr.s_addr) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr >> 8) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr >> 16) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr >> 24) & 0xff),
#else
(unsigned int) ((req->sa.sin_addr.s_addr >> 24) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr >> 16) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr >> 8) & 0xff),
(unsigned int) ((req->sa.sin_addr.s_addr) & 0xff),
#endif
output);
return (-1);
}
/*
look for :
resource.<domain>
auth.<domain>
...
cf. request.c
*/
while (dns_commands[i++].str)
{
if ( ( dns_commands[i-1].str_len + 1 + domain_len <= req_len )
&& ((ptr2 = strstr(ptr - dns_commands[i-1].str_len, dns_commands[i-1].str))))
{
ptr = ptr2;
req->cmd = &dns_commands[i-1];
break;
}
}
strcpy(req->domain, ptr);
*ptr = 0;
len = (unsigned int) (ptr - output);
/* delete dots */
for (i=0,j=0; i < len; ++i)
{
if (output[i] != '.')
{
if (i != j)
output[j] = output[i];
++j;
}
}
output[j] = 0;
return (0);
}
/*
Not a RFC compatible decoder
return -1 if domain is incorrect
dns_decode check max size of host
strip the domain name
*/
int dns_decode(t_conf *conf, t_request *req, char *input, char *output)
{
int total_len = 0;
uint8_t len;
char *ptr;
ptr = input;
*output = 0;
if (strlen(ptr) < (strlen(conf->my_domain) + 1))
return (-1);
while (*ptr)
{
len = (uint8_t) *ptr;
total_len += len;
if ((len > 63) || (total_len > MAX_HOST_NAME_ENCODED))
{
MYERROR("NAME TOO long %d %d", len, total_len + len);
return (-1);
}
strncat(output, ptr + 1, len);
output[total_len] = 0;
if (len)
{
if (++total_len > MAX_HOST_NAME_ENCODED)
return (-1);
strcat(output , ".");
len++;
}
ptr += (len);
}
if (total_len > 0)
output[total_len -1 ] = 0;
return (dns_strip_dot_and_domain(conf, req, output));
}
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