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
23 #if defined(WIN32) && !defined(WATT32)
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
30 #include <arpa/nameser.h>
31 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
32 #include <arpa/nameser_compat.h>
40 #include "ares_private.h"
42 int ares_parse_ns_reply( const unsigned char* abuf, int alen,
43 struct hostent** host )
45 unsigned int qdcount, ancount;
46 int status, i, rr_type, rr_class, rr_len;
49 const unsigned char *aptr;
50 char* hostname, *rr_name, *rr_data, **nameservers;
51 struct hostent *hostent;
53 /* Set *host to NULL for all failure cases. */
56 /* Give up if abuf doesn't have room for a header. */
57 if ( alen < HFIXEDSZ )
60 /* Fetch the question and answer count from the header. */
61 qdcount = DNS_HEADER_QDCOUNT( abuf );
62 ancount = DNS_HEADER_ANCOUNT( abuf );
66 /* Expand the name from the question, and skip past the question. */
67 aptr = abuf + HFIXEDSZ;
68 status = ares_expand_name( aptr, abuf, alen, &hostname, &len );
69 if ( status != ARES_SUCCESS )
71 if ( aptr + len + QFIXEDSZ > abuf + alen )
76 aptr += len + QFIXEDSZ;
78 /* Allocate nameservers array; ancount gives an upper bound */
79 nameservers = malloc( ( ancount + 1 ) * sizeof( char * ) );
87 /* Examine each answer resource record (RR) in turn. */
88 for ( i = 0; i < ( int ) ancount; i++ )
90 /* Decode the RR up to the data field. */
91 status = ares_expand_name( aptr, abuf, alen, &rr_name, &len );
92 if ( status != ARES_SUCCESS )
95 if ( aptr + RRFIXEDSZ > abuf + alen )
97 status = ARES_EBADRESP;
100 rr_type = DNS_RR_TYPE( aptr );
101 rr_class = DNS_RR_CLASS( aptr );
102 rr_len = DNS_RR_LEN( aptr );
105 if ( rr_class == C_IN && rr_type == T_NS )
107 /* Decode the RR data and add it to the nameservers list */
108 status = ares_expand_name( aptr, abuf, alen, &rr_data, &len );
109 if ( status != ARES_SUCCESS )
114 nameservers[nameservers_num] = malloc(strlen(rr_data)+1);
116 if (nameservers[nameservers_num]==NULL)
123 strcpy(nameservers[nameservers_num],rr_data);
132 if ( aptr > abuf + alen )
134 status = ARES_EBADRESP;
139 if ( status == ARES_SUCCESS && nameservers_num == 0 )
141 status = ARES_ENODATA;
143 if ( status == ARES_SUCCESS )
145 /* We got our answer. Allocate memory to build the host entry. */
146 nameservers[nameservers_num] = NULL;
147 hostent = malloc( sizeof( struct hostent ) );
150 hostent->h_addr_list = malloc( 1 * sizeof( char * ) );
151 if ( hostent->h_addr_list )
153 /* Fill in the hostent and return successfully. */
154 hostent->h_name = hostname;
155 hostent->h_aliases = nameservers;
156 hostent->h_addrtype = AF_INET;
157 hostent->h_length = sizeof( struct in_addr );
158 hostent->h_addr_list[0] = NULL;
164 status = ARES_ENOMEM;
166 for ( i = 0; i < nameservers_num; i++ )
167 free( nameservers[i] );