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Diffstat (limited to '')
| -rw-r--r-- | src/c-ares/ares_parse_ns_reply.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/src/c-ares/ares_parse_ns_reply.c b/src/c-ares/ares_parse_ns_reply.c new file mode 100644 index 00000000..7bb51429 --- /dev/null +++ b/src/c-ares/ares_parse_ns_reply.c @@ -0,0 +1,183 @@ +/* Copyright 1998 by the Massachusetts Institute of Technology. + * + * 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. + */ + +/* + * ares_parse_ns_reply created by Vlad Dinulescu <vlad.dinulescu@avira.com> + * on behalf of AVIRA Gmbh - http://www.avira.com + */ + +#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 +#ifdef HAVE_ARPA_NAMESER_H +# include <arpa/nameser.h> +#else +# include "nameser.h" +#endif +#ifdef HAVE_ARPA_NAMESER_COMPAT_H +# include <arpa/nameser_compat.h> +#endif + +#include "ares.h" +#include "ares_dns.h" +#include "ares_private.h" + +int ares_parse_ns_reply( const unsigned char* abuf, int alen, + struct hostent** host ) +{ + unsigned int qdcount, ancount; + int status, i, rr_type, rr_class, rr_len; + int nameservers_num; + long len; + const unsigned char *aptr; + char* hostname, *rr_name, *rr_data, **nameservers; + struct hostent *hostent; + + /* Set *host to NULL for all failure cases. */ + *host = NULL; + + /* Give up if abuf doesn't have room for a header. */ + if ( alen < HFIXEDSZ ) + return ARES_EBADRESP; + + /* Fetch the question and answer count from the header. */ + qdcount = DNS_HEADER_QDCOUNT( abuf ); + ancount = DNS_HEADER_ANCOUNT( abuf ); + if ( qdcount != 1 ) + return ARES_EBADRESP; + + /* Expand the name from the question, and skip past the question. */ + aptr = abuf + HFIXEDSZ; + status = ares__expand_name_for_response( aptr, abuf, alen, &hostname, &len); + if ( status != ARES_SUCCESS ) + return status; + if ( aptr + len + QFIXEDSZ > abuf + alen ) + { + ares_free( hostname ); + return ARES_EBADRESP; + } + aptr += len + QFIXEDSZ; + + /* Allocate nameservers array; ancount gives an upper bound */ + nameservers = ares_malloc( ( ancount + 1 ) * sizeof( char * ) ); + if ( !nameservers ) + { + ares_free( hostname ); + return ARES_ENOMEM; + } + nameservers_num = 0; + + /* Examine each answer resource record (RR) in turn. */ + for ( i = 0; i < ( int ) ancount; i++ ) + { + /* Decode the RR up to the data field. */ + status = ares__expand_name_for_response( aptr, abuf, alen, &rr_name, &len ); + if ( status != ARES_SUCCESS ) + break; + aptr += len; + if ( aptr + RRFIXEDSZ > abuf + alen ) + { + status = ARES_EBADRESP; + ares_free(rr_name); + break; + } + 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; + break; + } + + if ( rr_class == C_IN && rr_type == T_NS ) + { + /* Decode the RR data and add it to the nameservers list */ + status = ares__expand_name_for_response( aptr, abuf, alen, &rr_data, + &len); + if ( status != ARES_SUCCESS ) + { + ares_free(rr_name); + break; + } + + nameservers[nameservers_num] = ares_malloc(strlen(rr_data)+1); + + if (nameservers[nameservers_num]==NULL) + { + ares_free(rr_name); + ares_free(rr_data); + status=ARES_ENOMEM; + break; + } + strcpy(nameservers[nameservers_num],rr_data); + ares_free(rr_data); + + nameservers_num++; + } + + ares_free( rr_name ); + + aptr += rr_len; + if ( aptr > abuf + alen ) + { /* LCOV_EXCL_START: already checked above */ + status = ARES_EBADRESP; + break; + } /* LCOV_EXCL_STOP */ + } + + if ( status == ARES_SUCCESS && nameservers_num == 0 ) + { + status = ARES_ENODATA; + } + if ( status == ARES_SUCCESS ) + { + /* We got our answer. Allocate memory to build the host entry. */ + nameservers[nameservers_num] = NULL; + hostent = ares_malloc( sizeof( struct hostent ) ); + if ( hostent ) + { + hostent->h_addr_list = ares_malloc( 1 * sizeof( char * ) ); + if ( hostent->h_addr_list ) + { + /* Fill in the hostent and return successfully. */ + hostent->h_name = hostname; + hostent->h_aliases = nameservers; + hostent->h_addrtype = AF_INET; + hostent->h_length = sizeof( struct in_addr ); + hostent->h_addr_list[0] = NULL; + *host = hostent; + return ARES_SUCCESS; + } + ares_free( hostent ); + } + status = ARES_ENOMEM; + } + for ( i = 0; i < nameservers_num; i++ ) + ares_free( nameservers[i] ); + ares_free( nameservers ); + ares_free( hostname ); + return status; +} |