mirror of https://github.com/moparisthebest/curl
Jakub Hrozek added ares_parse_txt_reply() for TXT parsing
This commit is contained in:
parent
982e655c07
commit
950a034895
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@ -1,5 +1,8 @@
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Changelog for the c-ares project
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Changelog for the c-ares project
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* October 29, 2009 (Daniel Stenberg)
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- Jakub Hrozek added ares_parse_txt_reply() for TXT parsing
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* October 23, 2009 (Yang Tse)
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* October 23, 2009 (Yang Tse)
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- John Engelhart noticed an unreleased problem relative to a duplicate
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- John Engelhart noticed an unreleased problem relative to a duplicate
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ARES_ECANCELLED error code value and missing error code description.
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ARES_ECANCELLED error code value and missing error code description.
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@ -23,6 +23,8 @@ CSOURCES = ares__close_sockets.c \
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ares_parse_ns_reply.c \
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ares_parse_ns_reply.c \
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ares_parse_ptr_reply.c \
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ares_parse_ptr_reply.c \
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ares_parse_srv_reply.c \
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ares_parse_srv_reply.c \
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ares_parse_txt_reply.c \
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ares_free_txt_reply.c \
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ares_process.c \
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ares_process.c \
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ares_query.c \
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ares_query.c \
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ares_search.c \
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ares_search.c \
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@ -1,4 +1,4 @@
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This is what's new and changed in the c-ares 1.6.1 release:
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This is what's new and changed in the c-ares 1.7.0 release:
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Changed:
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Changed:
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@ -11,6 +11,7 @@ Changed:
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o new --enable-curldebug configure option
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o new --enable-curldebug configure option
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o ARES_ECANCELLED is now sent as reason for ares_cancel()
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o ARES_ECANCELLED is now sent as reason for ares_cancel()
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o added ares_parse_srv_reply()
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o added ares_parse_srv_reply()
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o added ares_parse_txt_reply()
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Fixed:
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Fixed:
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10
ares/ares.h
10
ares/ares.h
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@ -436,6 +436,11 @@ struct ares_srv_reply {
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char *host;
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char *host;
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};
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};
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struct ares_txt_reply {
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unsigned int length;
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unsigned char *txt;
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};
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/*
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/*
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** Parse the buffer, starting at *abuf and of length alen bytes, previously
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** Parse the buffer, starting at *abuf and of length alen bytes, previously
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** obtained from an ares_search call. Put the results in *host, if nonnull.
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** obtained from an ares_search call. Put the results in *host, if nonnull.
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@ -472,6 +477,11 @@ CARES_EXTERN int ares_parse_srv_reply(const unsigned char* abuf,
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struct ares_srv_reply** srv_out,
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struct ares_srv_reply** srv_out,
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int *nsrvreply);
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int *nsrvreply);
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CARES_EXTERN int ares_parse_txt_reply(const unsigned char* abuf,
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int alen,
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struct ares_txt_reply** txt_out,
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int *nsrvreply);
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CARES_EXTERN void ares_free_string(void *str);
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CARES_EXTERN void ares_free_string(void *str);
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CARES_EXTERN void ares_free_hostent(struct hostent *host);
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CARES_EXTERN void ares_free_hostent(struct hostent *host);
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@ -0,0 +1,77 @@
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.\"
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.\" Copyright 1998 by the Massachusetts Institute of Technology.
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.\"
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.\" Permission to use, copy, modify, and distribute this
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.\" software and its documentation for any purpose and without
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.\" fee is hereby granted, provided that the above copyright
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.\" notice appear in all copies and that both that copyright
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.\" notice and this permission notice appear in supporting
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.\" documentation, and that the name of M.I.T. not be used in
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.\" advertising or publicity pertaining to distribution of the
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.\" software without specific, written prior permission.
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.\" M.I.T. makes no representations about the suitability of
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.\" this software for any purpose. It is provided "as is"
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.\" without express or implied warranty.
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.\"
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.TH ARES_PARSE_TXT_REPLY 3 "27 October 2009"
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.SH NAME
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ares_parse_txt_reply \- Parse a reply to a DNS query of type TXT into a
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struct ares_txt_reply
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.SH SYNOPSIS
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.nf
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.B #include <ares.h>
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.PP
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.B int ares_parse_txt_reply(const unsigned char* \fIabuf\fP, int \fIalen\fP,
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.B struct ares_txt_reply **\fItxt_out\fP, int *\fIntxtreply\fP);
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.fi
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.SH DESCRIPTION
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The
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.B ares_parse_txt_reply
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function parses the response to a query of type TXT into a
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.I struct ares_txt_reply
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The parameters
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.I abuf
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and
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.I alen
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give the contents of the response. The result is stored in allocated
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memory and a pointer to it stored into the variable pointed to by
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.IR txt_out .
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The number of responses is stored into the variable pointed to by
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.IR ntxtreply .
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It is the caller's responsibility to free the resulting
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.IR txt_out
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structure when it is no longer needed.
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.PP
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The structure
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.I ares_txt_reply
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contains the following fields:
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.sp
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.in +4n
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.nf
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struct ares_txt_reply {
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unsigned int length;
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unsigned char *txt;
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};
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.fi
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.in
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.PP
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.SH RETURN VALUES
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.B ares_parse_txt_reply
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can return any of the following values:
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.TP 15
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.B ARES_SUCCESS
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The response was successfully parsed.
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.TP 15
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.B ARES_EBADRESP
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The response was malformatted.
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.TP 15
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.B ARES_ENODATA
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The response did not contain an answer to the query.
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.TP 15
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.B ARES_ENOMEM
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Memory was exhausted.
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.SH SEE ALSO
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.BR ares_query (3)
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.SH AUTHOR
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Written by Jakub Hrozek <jhrozek@redhat.com>, on behalf of Red Hat, Inc http://www.redhat.com
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@ -0,0 +1,176 @@
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/* Copyright (C) 2009 Jakub Hrozek <jhrozek@redhat.com>
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#if defined(WIN32) && !defined(WATT32)
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#include "nameser.h"
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#else
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <arpa/nameser.h>
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#ifdef HAVE_ARPA_NAMESER_COMPAT_H
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#include <arpa/nameser_compat.h>
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#endif
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include "ares.h"
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#include "ares_dns.h"
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#include "ares_private.h"
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int
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ares_parse_txt_reply (const unsigned char *abuf, int alen,
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struct ares_txt_reply **txt_out, int *ntxtreply)
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{
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unsigned char substr_len = 0;
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unsigned char str_len = 0;
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unsigned int qdcount, ancount;
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const unsigned char *aptr;
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const unsigned char *strptr;
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int status, i, rr_type, rr_class, rr_len;
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long len;
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char *hostname = NULL, *rr_name = NULL;
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struct ares_txt_reply *txt = NULL;
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*txt_out = NULL;
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/* Give up if abuf doesn't have room for a header. */
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if (alen < HFIXEDSZ)
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return ARES_EBADRESP;
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/* Fetch the question and answer count from the header. */
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qdcount = DNS_HEADER_QDCOUNT (abuf);
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ancount = DNS_HEADER_ANCOUNT (abuf);
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if (qdcount != 1)
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return ARES_EBADRESP;
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if (ancount == 0)
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return ARES_ENODATA;
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/* Expand the name from the question, and skip past the question. */
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aptr = abuf + HFIXEDSZ;
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status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
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if (status != ARES_SUCCESS)
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return status;
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if (aptr + len + QFIXEDSZ > abuf + alen)
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{
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free (hostname);
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return ARES_EBADRESP;
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}
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aptr += len + QFIXEDSZ;
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/* Allocate ares_txt_reply array; ancount gives an upper bound */
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txt = malloc ((ancount) * sizeof (struct ares_txt_reply));
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if (!txt)
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{
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free (hostname);
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return ARES_ENOMEM;
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}
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/* Zero out so we can safely free txt.txt even if NULL */
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memset(txt, 0, ancount * sizeof (struct ares_txt_reply));
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/* Examine each answer resource record (RR) in turn. */
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for (i = 0; i < (int) ancount; i++)
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{
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/* Decode the RR up to the data field. */
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status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
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if (status != ARES_SUCCESS)
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{
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break;
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}
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aptr += len;
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if (aptr + RRFIXEDSZ > abuf + alen)
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{
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status = ARES_EBADRESP;
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break;
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}
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rr_type = DNS_RR_TYPE (aptr);
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rr_class = DNS_RR_CLASS (aptr);
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rr_len = DNS_RR_LEN (aptr);
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aptr += RRFIXEDSZ;
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/* Check if we are really looking at a TXT record */
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if (rr_class == C_IN && rr_type == T_TXT)
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{
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/*
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* There may be multiple substrings in a single TXT record. Each
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* substring may be up to 255 characters in length, with a
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* "length byte" indicating the size of the substring payload.
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* RDATA contains both the length-bytes and payloads of all
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* substrings contained therein.
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*/
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/* Realloc would be expensive, compute the total length */
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txt[i].length = 0;
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strptr = aptr;
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while (strptr < (aptr + rr_len))
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{
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memcpy ((void *) &substr_len, strptr, sizeof (unsigned char));
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txt[i].length += substr_len;
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strptr += substr_len + 1;
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}
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/* Including null byte */
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txt[i].txt = malloc (sizeof (unsigned char) * (txt[i].length + 1));
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if (txt[i].txt == NULL)
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{
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status = ARES_ENOMEM;
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break;
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}
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/* Step through the list of substrings, concatenating them */
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substr_len = 0;
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str_len = 0;
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strptr = aptr;
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while (strptr < (aptr + rr_len))
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{
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memcpy ((void *) &substr_len, strptr, sizeof (unsigned char));
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strptr++;
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memcpy ((void *) txt[i].txt + str_len, strptr,
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sizeof (unsigned char) * substr_len);
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str_len += substr_len;
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strptr += substr_len;
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}
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/* Make sure we NULL-terminate */
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txt[i].txt[txt[i].length] = '\0';
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/* Move on to the next record */
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aptr += rr_len;
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}
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/* Don't lose memory in the next iteration */
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free (rr_name);
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rr_name = NULL;
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}
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free (hostname);
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free (rr_name);
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/* clean up on error */
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if (status != ARES_SUCCESS)
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{
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ares_free_txt_reply(txt, ancount);
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return status;
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}
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/* everything looks fine, return the data */
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*txt_out = txt;
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*ntxtreply = ancount;
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return 0;
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}
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