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c-ares
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added ares_parse_mx_reply

This commit is contained in:
Jérémy Lal 2010-04-18 00:29:26 +02:00 committed by Daniel Stenberg
parent f28874d323
commit 63918fca76
7 changed files with 286 additions and 0 deletions
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4
Makefile.inc
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@ -23,6 +23,7 @@ CSOURCES = ares__close_sockets.c \
ares_options.c \
ares_parse_a_reply.c \
ares_parse_aaaa_reply.c \
ares_parse_mx_reply.c \
ares_parse_ns_reply.c \
ares_parse_ptr_reply.c \
ares_parse_srv_reply.c \
@ -86,6 +87,7 @@ MANPAGES = ares_cancel.3 \
ares_mkquery.3 \
ares_parse_a_reply.3 \
ares_parse_aaaa_reply.3 \
ares_parse_mx_reply.3 \
ares_parse_ns_reply.3 \
ares_parse_ptr_reply.3 \
ares_parse_srv_reply.3 \
@ -124,6 +126,7 @@ HTMLPAGES = ares_cancel.html \
ares_mkquery.html \
ares_parse_a_reply.html \
ares_parse_aaaa_reply.html \
ares_parse_mx_reply.html \
ares_parse_ns_reply.html \
ares_parse_ptr_reply.html \
ares_parse_srv_reply.html \
@ -162,6 +165,7 @@ PDFPAGES = ares_cancel.pdf \
ares_mkquery.pdf \
ares_parse_a_reply.pdf \
ares_parse_aaaa_reply.pdf \
ares_parse_mx_reply.pdf \
ares_parse_ns_reply.pdf \
ares_parse_ptr_reply.pdf \
ares_parse_srv_reply.pdf \

10
ares.h
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@ -433,6 +433,12 @@ struct ares_srv_reply {
unsigned short port;
};
struct ares_mx_reply {
struct ares_mx_reply *next;
char *host;
unsigned short priority;
};
struct ares_txt_reply {
struct ares_txt_reply *next;
unsigned char *txt;
@ -474,6 +480,10 @@ CARES_EXTERN int ares_parse_srv_reply(const unsigned char* abuf,
int alen,
struct ares_srv_reply** srv_out);
CARES_EXTERN int ares_parse_mx_reply(const unsigned char* abuf,
int alen,
struct ares_mx_reply** mx_out);
CARES_EXTERN int ares_parse_txt_reply(const unsigned char* abuf,
int alen,
struct ares_txt_reply** txt_out);

14
ares_data.c
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@ -62,6 +62,14 @@ void ares_free_data(void *dataptr)
switch (ptr->type)
{
case ARES_DATATYPE_MX_REPLY:
if (ptr->data.mx_reply.next)
ares_free_data(ptr->data.mx_reply.next);
if (ptr->data.mx_reply.host)
free(ptr->data.mx_reply.host);
break;
case ARES_DATATYPE_SRV_REPLY:
if (ptr->data.srv_reply.next)
@ -113,6 +121,12 @@ void *ares_malloc_data(ares_datatype type)
switch (type)
{
case ARES_DATATYPE_MX_REPLY:
ptr->data.mx_reply.next = NULL;
ptr->data.mx_reply.host = NULL;
ptr->data.mx_reply.priority = 0;
break;
case ARES_DATATYPE_SRV_REPLY:
ptr->data.srv_reply.next = NULL;
ptr->data.srv_reply.host = NULL;

2
ares_data.h
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@ -19,6 +19,7 @@ typedef enum {
ARES_DATATYPE_SRV_REPLY, /* struct ares_srv_reply - introduced in 1.7.0 */
ARES_DATATYPE_TXT_REPLY, /* struct ares_txt_reply - introduced in 1.7.0 */
ARES_DATATYPE_ADDR_NODE, /* struct ares_addr_node - introduced in 1.7.1 */
ARES_DATATYPE_MX_REPLY, /* struct ares_mx_reply - introduced in 1.7.2 */
#if 0
ARES_DATATYPE_ADDR6TTL, /* struct ares_addrttl */
ARES_DATATYPE_ADDRTTL, /* struct ares_addr6ttl */
@ -55,6 +56,7 @@ struct ares_data {
struct ares_txt_reply txt_reply;
struct ares_srv_reply srv_reply;
struct ares_addr_node addr_node;
struct ares_mx_reply mx_reply;
} data;
};

7
ares_free_data.3
View File

@ -44,6 +44,12 @@ will free the whole linked list of ares_srv_reply structures returned
by ares_parse_srv_reply(3), along with any additional storage
associated with those structures.
.TP
.B ares_parse_mx_reply(3)
When used to free the data returned by ares_parse_mx_reply(3) this
will free the whole linked list of ares_mx_reply structures returned
by ares_parse_mx_reply(3), along with any additional storage
associated with those structures.
.TP
.B ares_parse_txt_reply(3)
When used to free the data returned by ares_parse_txt_reply(3) this
will free the whole linked list of ares_txt_reply structures returned
@ -56,6 +62,7 @@ This function was first introduced in c-ares version 1.7.0.
.SH SEE ALSO
.BR ares_get_servers(3),
.BR ares_parse_srv_reply(3),
.BR ares_parse_mx_reply(3),
.BR ares_parse_txt_reply(3)
.SH AUTHOR
Yang Tse

79
ares_parse_mx_reply.3 Normal file
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@ -0,0 +1,79 @@
.\"
.\" 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_MX_REPLY 3 "4 August 2009"
.SH NAME
ares_parse_mx_reply \- Parse a reply to a DNS query of type MX
.SH SYNOPSIS
.nf
.B #include <ares.h>
.PP
.B int ares_parse_mx_reply(const unsigned char* \fIabuf\fP, int \fIalen\fP,
.B struct ares_mx_reply** \fImx_out\fP);
.fi
.SH DESCRIPTION
The
.B ares_parse_mx_reply
function parses the response to a query of type MX into a
linked list of
.I struct ares_mx_reply
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 mx_out .
It is the caller's responsibility to free the resulting
.IR mx_out
structure when it is no longer needed using the function
.B ares_free_data
.PP
The structure
.I ares_mx_reply
contains the following fields:
.sp
.in +4n
.nf
struct ares_mx_reply {
struct ares_mx_reply *next;
char *host;
unsigned short priority;
};
.fi
.in
.PP
.SH RETURN VALUES
.B ares_parse_mx_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 AVAILABILITY
This function was first introduced in c-ares version 1.7.2.
.SH SEE ALSO
.BR ares_query (3)
.BR ares_free_data (3)
.SH AUTHOR
Written by Jeremy Lal <kapouer@melix.org>

170
ares_parse_mx_reply.c Normal file
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@ -0,0 +1,170 @@
/* Copyright 1998 by the Massachusetts Institute of Technology.
* Copyright (C) 2010 Jeremy Lal <kapouer@melix.org>
*
* 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.
*/
#include "ares_setup.h"
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.h>
#endif
#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 <stdlib.h>
#include <string.h>
#include "ares.h"
#include "ares_dns.h"
#include "ares_data.h"
#include "ares_private.h"
int
ares_parse_mx_reply (const unsigned char *abuf, int alen,
struct ares_mx_reply **mx_out)
{
unsigned int qdcount, ancount, i;
const unsigned char *aptr, *vptr;
int status, rr_type, rr_class, rr_len;
long len;
char *hostname = NULL, *rr_name = NULL;
struct ares_mx_reply *mx_head = NULL;
struct ares_mx_reply *mx_last = NULL;
struct ares_mx_reply *mx_curr;
/* Set *mx_out to NULL for all failure cases. */
*mx_out = 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;
if (ancount == 0)
return ARES_ENODATA;
/* 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;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < 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;
/* Check if we are really looking at a MX record */
if (rr_class == C_IN && rr_type == T_MX)
{
/* parse the MX record itself */
if (rr_len < 2)
{
status = ARES_EBADRESP;
break;
}
/* Allocate storage for this MX answer appending it to the list */
mx_curr = ares_malloc_data(ARES_DATATYPE_MX_REPLY);
if (!mx_curr)
{
status = ARES_ENOMEM;
break;
}
if (mx_last)
{
mx_last->next = mx_curr;
}
else
{
mx_head = mx_curr;
}
mx_last = mx_curr;
vptr = aptr;
mx_curr->priority = ntohs (*((unsigned short *)vptr));
vptr += sizeof(unsigned short);
status = ares_expand_name (vptr, abuf, alen, &mx_curr->host, &len);
if (status != ARES_SUCCESS)
break;
}
/* Don't lose memory in the next iteration */
free (rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
/* clean up on error */
if (status != ARES_SUCCESS)
{
if (mx_head)
ares_free_data (mx_head);
return status;
}
/* everything looks fine, return the data */
*mx_out = mx_head;
return ARES_SUCCESS;
}