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Vlad Dinulescu added ares_parse_ns_reply()

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1 parent 7bf2332 commit c1bc4c19be3b4c2858e62241318350cd52cbef86 @bagder bagder committed Feb 19, 2007
Showing with 251 additions and 6 deletions.
  1. +4 −0 CHANGES
  2. +7 −6 Makefile.inc
  3. +2 −0 ares.h
  4. +66 −0 ares_parse_ns_reply.3
  5. +172 −0 ares_parse_ns_reply.c
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@@ -1,5 +1,9 @@
Changelog for the c-ares project
+* February 19
+
+- Vlad Dinulescu added ares_parse_ns_reply().
+
* February 13
- Yang Tse: Fix failure to get the search sequence of /etc/hosts and
View
@@ -5,17 +5,18 @@ ares_gethostbyname.c ares_strerror.c ares_cancel.c ares_init.c \
ares_timeout.c ares_destroy.c ares_mkquery.c ares_version.c \
ares_expand_name.c ares_parse_a_reply.c windows_port.c \
ares_expand_string.c ares_parse_ptr_reply.c ares_parse_aaaa_reply.c \
-ares_getnameinfo.c inet_net_pton.c bitncmp.c inet_ntop.c
+ares_getnameinfo.c inet_net_pton.c bitncmp.c inet_ntop.c \
+ares_parse_ns_reply.c
HHEADERS = ares.h ares_private.h setup.h ares_dns.h ares_version.h \
nameser.h inet_net_pton.h inet_ntop.h ares_ipv6.h bitncmp.h \
setup_once.h
MANPAGES= ares_destroy.3 ares_expand_name.3 ares_expand_string.3 ares_fds.3 \
- ares_free_hostent.3 ares_free_string.3 ares_gethostbyaddr.3 \
- ares_gethostbyname.3 ares_init.3 ares_init_options.3 ares_mkquery.3 \
- ares_parse_a_reply.3 ares_parse_ptr_reply.3 ares_process.3 \
- ares_query.3 ares_search.3 ares_send.3 ares_strerror.3 ares_timeout.3 \
+ ares_free_hostent.3 ares_free_string.3 ares_gethostbyaddr.3 \
+ ares_gethostbyname.3 ares_init.3 ares_init_options.3 ares_mkquery.3 \
+ ares_parse_a_reply.3 ares_parse_ptr_reply.3 ares_process.3 \
+ ares_query.3 ares_search.3 ares_send.3 ares_strerror.3 ares_timeout.3 \
ares_version.3 ares_cancel.3 ares_parse_aaaa_reply.3 ares_getnameinfo.3 \
- ares_getsock.3
+ ares_getsock.3 ares_parse_ns_reply.3
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@@ -213,6 +213,8 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
struct hostent **host);
int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
int addrlen, int family, struct hostent **host);
+int ares_parse_ns_reply(const unsigned char *abuf, int alen,
+ struct hostent **host);
void ares_free_string(void *str);
void ares_free_hostent(struct hostent *host);
const char *ares_strerror(int code);
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@@ -0,0 +1,66 @@
+.\"
+.\" 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.
+.\"
+.TH ARES_PARSE_NS_REPLY 3 "10 February 2007"
+.SH NAME
+ares_parse_ns_reply \- Parse a reply to a DNS query of type NS into a hostent
+.SH SYNOPSIS
+.nf
+.B #include <ares.h>
+.PP
+.B int ares_parse_ns_reply(const unsigned char *\fIabuf\fP, int \fIalen\fP,
+.B struct hostent **\fIhost\fP);
+.fi
+.SH DESCRIPTION
+The
+.B ares_parse_ns_reply
+function parses the response to a query of type NS into a
+.BR "struct hostent" .
+The parameters
+.I abuf
+and
+.I alen
+give the contents of the response. The result is stored in allocated
+memory and a pointer to it stored into the variable pointed to by
+.IR host .
+The nameservers are stored into the
+.BR aliases
+field of the
+.IR host
+structure.
+It is the caller's responsibility to free the resulting host structure
+using
+.BR ares_free_hostent (3)
+when it is no longer needed.
+.SH RETURN VALUES
+.B ares_parse_ns_reply
+can return any of the following values:
+.TP 15
+.B ARES_SUCCESS
+The response was successfully parsed.
+.TP 15
+.B ARES_EBADRESP
+The response was malformatted.
+.TP 15
+.B ARES_ENODATA
+The response did not contain an answer to the query.
+.TP 15
+.B ARES_ENOMEM
+Memory was exhausted.
+.SH SEE ALSO
+.BR ares_query (3),
+.BR ares_free_hostent (3)
+.SH AUTHOR
+Written by Vlad Dinulescu <vlad.dinulescu@avira.com>, on behalf of AVIRA Gmbh http://www.avira.com
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@@ -0,0 +1,172 @@
+/* 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 "setup.h"
+#include <sys/types.h>
+
+#if defined(WIN32) && !defined(WATT32)
+#include "nameser.h"
+#else
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <arpa/nameser.h>
+#ifdef HAVE_ARPA_NAMESER_COMPAT_H
+#include <arpa/nameser_compat.h>
+#endif
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#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( aptr, abuf, alen, &hostname, &len );
+ if ( status != ARES_SUCCESS )
+ return status;
+ if ( aptr + len + QFIXEDSZ > abuf + alen )
+ {
+ free( hostname );
+ return ARES_EBADRESP;
+ }
+ aptr += len + QFIXEDSZ;
+
+ /* Allocate nameservers array; ancount gives an upper bound */
+ nameservers = malloc( ( ancount + 1 ) * sizeof( char * ) );
+ if ( !nameservers )
+ {
+ 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( aptr, abuf, alen, &rr_name, &len );
+ if ( status != ARES_SUCCESS )
+ break;
+ aptr += len;
+ if ( aptr + RRFIXEDSZ > abuf + alen )
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ rr_type = DNS_RR_TYPE( aptr );
+ rr_class = DNS_RR_CLASS( aptr );
+ rr_len = DNS_RR_LEN( aptr );
+ aptr += RRFIXEDSZ;
+
+ if ( rr_class == C_IN && rr_type == T_NS )
+ {
+ /* Decode the RR data and add it to the nameservers list */
+ status = ares_expand_name( aptr, abuf, alen, &rr_data, &len );
+ if ( status != ARES_SUCCESS )
+ {
+ break;
+ }
+
+ nameservers[nameservers_num] = malloc(strlen(rr_data)+1);
+
+ if (nameservers[nameservers_num]==NULL)
+ {
+ free(rr_name);
+ free(rr_data);
+ status=ARES_ENOMEM;
+ break;
+ }
+ strcpy(nameservers[nameservers_num],rr_data);
+ free(rr_data);
+
+ nameservers_num++;
+ }
+
+ free( rr_name );
+
+ aptr += rr_len;
+ if ( aptr > abuf + alen )
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ }
+
+ 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 = malloc( sizeof( struct hostent ) );
+ if ( hostent )
+ {
+ hostent->h_addr_list = 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;
+ }
+ free( hostent );
+ }
+ status = ARES_ENOMEM;
+ }
+ for ( i = 0; i < nameservers_num; i++ )
+ free( nameservers[i] );
+ free( nameservers );
+ free( hostname );
+ return status;
+}

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