1 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Permission to use, copy, modify, and distribute this
4 * software and its documentation for any purpose and without
5 * fee is hereby granted, provided that the above copyright
6 * notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting
8 * documentation, and that the name of M.I.T. not be used in
9 * advertising or publicity pertaining to distribution of the
10 * software without specific, written prior permission.
11 * M.I.T. makes no representations about the suitability of
12 * this software for any purpose. It is provided "as is"
13 * without express or implied warranty.
17 * ares_parse_ns_reply created by Vlad Dinulescu <vlad.dinulescu@avira.com>
18 * on behalf of AVIRA Gmbh - http://www.avira.com
21 #include "ares_setup.h"
23 #ifdef HAVE_NETINET_IN_H
24 # include <netinet/in.h>
29 #ifdef HAVE_ARPA_INET_H
30 # include <arpa/inet.h>
32 #ifdef HAVE_ARPA_NAMESER_H
33 # include <arpa/nameser.h>
37 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
38 # include <arpa/nameser_compat.h>
43 #include "ares_private.h"
45 int ares_parse_ns_reply( const unsigned char* abuf, int alen,
46 struct hostent** host )
48 unsigned int qdcount, ancount;
49 int status, i, rr_type, rr_class, rr_len;
52 const unsigned char *aptr;
53 char* hostname, *rr_name, *rr_data, **nameservers;
54 struct hostent *hostent;
56 /* Set *host to NULL for all failure cases. */
59 /* Give up if abuf doesn't have room for a header. */
60 if ( alen < HFIXEDSZ )
63 /* Fetch the question and answer count from the header. */
64 qdcount = DNS_HEADER_QDCOUNT( abuf );
65 ancount = DNS_HEADER_ANCOUNT( abuf );
69 /* Expand the name from the question, and skip past the question. */
70 aptr = abuf + HFIXEDSZ;
71 status = ares__expand_name_for_response( aptr, abuf, alen, &hostname, &len);
72 if ( status != ARES_SUCCESS )
74 if ( aptr + len + QFIXEDSZ > abuf + alen )
79 aptr += len + QFIXEDSZ;
81 /* Allocate nameservers array; ancount gives an upper bound */
82 nameservers = malloc( ( ancount + 1 ) * sizeof( char * ) );
90 /* Examine each answer resource record (RR) in turn. */
91 for ( i = 0; i < ( int ) ancount; i++ )
93 /* Decode the RR up to the data field. */
94 status = ares__expand_name_for_response( aptr, abuf, alen, &rr_name, &len );
95 if ( status != ARES_SUCCESS )
98 if ( aptr + RRFIXEDSZ > abuf + alen )
100 status = ARES_EBADRESP;
104 rr_type = DNS_RR_TYPE( aptr );
105 rr_class = DNS_RR_CLASS( aptr );
106 rr_len = DNS_RR_LEN( aptr );
108 if (aptr + rr_len > abuf + alen)
111 status = ARES_EBADRESP;
115 if ( rr_class == C_IN && rr_type == T_NS )
117 /* Decode the RR data and add it to the nameservers list */
118 status = ares__expand_name_for_response( aptr, abuf, alen, &rr_data,
120 if ( status != ARES_SUCCESS )
126 nameservers[nameservers_num] = malloc(strlen(rr_data)+1);
128 if (nameservers[nameservers_num]==NULL)
135 strcpy(nameservers[nameservers_num],rr_data);
144 if ( aptr > abuf + alen )
146 status = ARES_EBADRESP;
151 if ( status == ARES_SUCCESS && nameservers_num == 0 )
153 status = ARES_ENODATA;
155 if ( status == ARES_SUCCESS )
157 /* We got our answer. Allocate memory to build the host entry. */
158 nameservers[nameservers_num] = NULL;
159 hostent = malloc( sizeof( struct hostent ) );
162 hostent->h_addr_list = malloc( 1 * sizeof( char * ) );
163 if ( hostent->h_addr_list )
165 /* Fill in the hostent and return successfully. */
166 hostent->h_name = hostname;
167 hostent->h_aliases = nameservers;
168 hostent->h_addrtype = AF_INET;
169 hostent->h_length = sizeof( struct in_addr );
170 hostent->h_addr_list[0] = NULL;
176 status = ARES_ENOMEM;
178 for ( i = 0; i < nameservers_num; i++ )
179 free( nameservers[i] );