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/* Copyright 1998 by the Massachusetts Institute of Technology.
* Copyright (C) 2012 Marko Kreen <markokr@gmail.com>
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#include "ares_setup.h"
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
# include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif
#include "ares_nameser.h"
#include "ares.h"
#include "ares_dns.h"
#include "ares_data.h"
#include "ares_private.h"
int
ares_parse_soa_reply(const unsigned char *abuf, int alen,
struct ares_soa_reply **soa_out)
{
const unsigned char *aptr;
long len;
char *qname = NULL, *rr_name = NULL;
struct ares_soa_reply *soa = NULL;
int qdcount, ancount, qclass;
int status, i, rr_type, rr_class, rr_len;
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* parse message header */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_EBADRESP;
aptr = abuf + HFIXEDSZ;
/* query name */
status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len, 0);
if (status != ARES_SUCCESS)
goto failed_stat;
if (alen <= len + HFIXEDSZ + 1)
goto failed;
aptr += len;
qclass = DNS_QUESTION_TYPE(aptr);
/* skip qtype & qclass */
if (aptr + QFIXEDSZ > abuf + alen)
goto failed;
aptr += QFIXEDSZ;
/* qclass of SOA with multiple answers */
if (qclass == T_SOA && ancount > 1)
goto failed;
/* examine all the records, break and return if found soa */
for (i = 0; i < ancount; i++)
{
rr_name = NULL;
status = ares__expand_name_for_response (aptr, abuf, alen, &rr_name, &len, 0);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
if ( aptr + RRFIXEDSZ > abuf + alen )
{
ares_free(rr_name);
status = ARES_EBADRESP;
goto failed_stat;
}
rr_type = DNS_RR_TYPE( aptr );
rr_class = DNS_RR_CLASS( aptr );
rr_len = DNS_RR_LEN( aptr );
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
ares_free(rr_name);
status = ARES_EBADRESP;
goto failed_stat;
}
if ( rr_class == C_IN && rr_type == T_SOA )
{
/* allocate result struct */
soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
if (!soa)
{
ares_free(rr_name);
status = ARES_ENOMEM;
goto failed_stat;
}
/* nsname */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname,
&len, 0);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
/* hostmaster */
status = ares__expand_name_for_response(aptr, abuf, alen,
&soa->hostmaster, &len, 0);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
/* integer fields */
if (aptr + 5 * 4 > abuf + alen)
{
ares_free(rr_name);
goto failed;
}
soa->serial = DNS__32BIT(aptr + 0 * 4);
soa->refresh = DNS__32BIT(aptr + 1 * 4);
soa->retry = DNS__32BIT(aptr + 2 * 4);
soa->expire = DNS__32BIT(aptr + 3 * 4);
soa->minttl = DNS__32BIT(aptr + 4 * 4);
ares_free(qname);
ares_free(rr_name);
*soa_out = soa;
return ARES_SUCCESS;
}
aptr += rr_len;
ares_free(rr_name);
if (aptr > abuf + alen)
goto failed_stat;
}
/* no SOA record found */
status = ARES_EBADRESP;
goto failed_stat;
failed:
status = ARES_EBADRESP;
failed_stat:
if (soa)
ares_free_data(soa);
if (qname)
ares_free(qname);
return status;
}
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