2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Copyright (C) 2010 Jeremy Lal <kapouer@melix.org>
5 * Permission to use, copy, modify, and distribute this
6 * software and its documentation for any purpose and without
7 * fee is hereby granted, provided that the above copyright
8 * notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting
10 * documentation, and that the name of M.I.T. not be used in
11 * advertising or publicity pertaining to distribution of the
12 * software without specific, written prior permission.
13 * M.I.T. makes no representations about the suitability of
14 * this software for any purpose. It is provided "as is"
15 * without express or implied warranty.
18 #include "ares_setup.h"
20 #ifdef HAVE_NETINET_IN_H
21 # include <netinet/in.h>
26 #ifdef HAVE_ARPA_INET_H
27 # include <arpa/inet.h>
29 #ifdef HAVE_ARPA_NAMESER_H
30 # include <arpa/nameser.h>
34 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
35 # include <arpa/nameser_compat.h>
40 #include "ares_data.h"
41 #include "ares_private.h"
44 ares_parse_mx_reply (const unsigned char *abuf, int alen,
45 struct ares_mx_reply **mx_out)
47 unsigned int qdcount, ancount, i;
48 const unsigned char *aptr, *vptr;
49 int status, rr_type, rr_class, rr_len;
51 char *hostname = NULL, *rr_name = NULL;
52 struct ares_mx_reply *mx_head = NULL;
53 struct ares_mx_reply *mx_last = NULL;
54 struct ares_mx_reply *mx_curr;
56 /* Set *mx_out to NULL for all failure cases. */
59 /* Give up if abuf doesn't have room for a header. */
63 /* Fetch the question and answer count from the header. */
64 qdcount = DNS_HEADER_QDCOUNT (abuf);
65 ancount = DNS_HEADER_ANCOUNT (abuf);
71 /* Expand the name from the question, and skip past the question. */
72 aptr = abuf + HFIXEDSZ;
73 status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
74 if (status != ARES_SUCCESS)
77 if (aptr + len + QFIXEDSZ > abuf + alen)
82 aptr += len + QFIXEDSZ;
84 /* Examine each answer resource record (RR) in turn. */
85 for (i = 0; i < ancount; i++)
87 /* Decode the RR up to the data field. */
88 status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
89 if (status != ARES_SUCCESS)
94 if (aptr + RRFIXEDSZ > abuf + alen)
96 status = ARES_EBADRESP;
99 rr_type = DNS_RR_TYPE (aptr);
100 rr_class = DNS_RR_CLASS (aptr);
101 rr_len = DNS_RR_LEN (aptr);
104 /* Check if we are really looking at a MX record */
105 if (rr_class == C_IN && rr_type == T_MX)
107 /* parse the MX record itself */
110 status = ARES_EBADRESP;
114 /* Allocate storage for this MX answer appending it to the list */
115 mx_curr = ares_malloc_data(ARES_DATATYPE_MX_REPLY);
118 status = ARES_ENOMEM;
123 mx_last->next = mx_curr;
132 mx_curr->priority = DNS__16BIT(vptr);
133 vptr += sizeof(unsigned short);
135 status = ares_expand_name (vptr, abuf, alen, &mx_curr->host, &len);
136 if (status != ARES_SUCCESS)
140 /* Don't lose memory in the next iteration */
144 /* Move on to the next record */
153 /* clean up on error */
154 if (status != ARES_SUCCESS)
157 ares_free_data (mx_head);
161 /* everything looks fine, return the data */