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_SYS_SOCKET_H
24 # include <sys/socket.h>
26 #ifdef HAVE_NETINET_IN_H
27 # include <netinet/in.h>
32 #ifdef HAVE_ARPA_INET_H
33 # include <arpa/inet.h>
35 #ifdef HAVE_ARPA_NAMESER_H
36 # include <arpa/nameser.h>
40 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
41 # include <arpa/nameser_compat.h>
48 #include "ares_private.h"
50 int ares_parse_ns_reply( const unsigned char* abuf, int alen,
51 struct hostent** host )
53 unsigned int qdcount, ancount;
54 int status, i, rr_type, rr_class, rr_len;
57 const unsigned char *aptr;
58 char* hostname, *rr_name, *rr_data, **nameservers;
59 struct hostent *hostent;
61 /* Set *host to NULL for all failure cases. */
64 /* Give up if abuf doesn't have room for a header. */
65 if ( alen < HFIXEDSZ )
68 /* Fetch the question and answer count from the header. */
69 qdcount = DNS_HEADER_QDCOUNT( abuf );
70 ancount = DNS_HEADER_ANCOUNT( abuf );
74 /* Expand the name from the question, and skip past the question. */
75 aptr = abuf + HFIXEDSZ;
76 status = ares__expand_name_for_response( aptr, abuf, alen, &hostname, &len);
77 if ( status != ARES_SUCCESS )
79 if ( aptr + len + QFIXEDSZ > abuf + alen )
84 aptr += len + QFIXEDSZ;
86 /* Allocate nameservers array; ancount gives an upper bound */
87 nameservers = malloc( ( ancount + 1 ) * sizeof( char * ) );
95 /* Examine each answer resource record (RR) in turn. */
96 for ( i = 0; i < ( int ) ancount; i++ )
98 /* Decode the RR up to the data field. */
99 status = ares__expand_name_for_response( aptr, abuf, alen, &rr_name, &len );
100 if ( status != ARES_SUCCESS )
103 if ( aptr + RRFIXEDSZ > abuf + alen )
105 status = ARES_EBADRESP;
109 rr_type = DNS_RR_TYPE( aptr );
110 rr_class = DNS_RR_CLASS( aptr );
111 rr_len = DNS_RR_LEN( aptr );
114 if ( rr_class == C_IN && rr_type == T_NS )
116 /* Decode the RR data and add it to the nameservers list */
117 status = ares__expand_name_for_response( aptr, abuf, alen, &rr_data,
119 if ( status != ARES_SUCCESS )
125 nameservers[nameservers_num] = malloc(strlen(rr_data)+1);
127 if (nameservers[nameservers_num]==NULL)
134 strcpy(nameservers[nameservers_num],rr_data);
143 if ( aptr > abuf + alen )
145 status = ARES_EBADRESP;
150 if ( status == ARES_SUCCESS && nameservers_num == 0 )
152 status = ARES_ENODATA;
154 if ( status == ARES_SUCCESS )
156 /* We got our answer. Allocate memory to build the host entry. */
157 nameservers[nameservers_num] = NULL;
158 hostent = malloc( sizeof( struct hostent ) );
161 hostent->h_addr_list = malloc( 1 * sizeof( char * ) );
162 if ( hostent->h_addr_list )
164 /* Fill in the hostent and return successfully. */
165 hostent->h_name = hostname;
166 hostent->h_aliases = nameservers;
167 hostent->h_addrtype = AF_INET;
168 hostent->h_length = sizeof( struct in_addr );
169 hostent->h_addr_list[0] = NULL;
175 status = ARES_ENOMEM;
177 for ( i = 0; i < nameservers_num; i++ )
178 free( nameservers[i] );