1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Copyright (C) 2012 Marko Kreen <markokr@gmail.com>
4 *
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.
16 */
17
18 #include "ares_setup.h"
19
20 #ifdef HAVE_NETINET_IN_H
21 # include <netinet/in.h>
22 #endif
23 #ifdef HAVE_NETDB_H
24 # include <netdb.h>
25 #endif
26 #ifdef HAVE_ARPA_INET_H
27 # include <arpa/inet.h>
28 #endif
29 #ifdef HAVE_ARPA_NAMESER_H
30 # include <arpa/nameser.h>
31 #else
32 # include "nameser.h"
33 #endif
34 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
35 # include <arpa/nameser_compat.h>
36 #endif
37
38 #include "ares.h"
39 #include "ares_dns.h"
40 #include "ares_data.h"
41 #include "ares_private.h"
42
43 int
ares_parse_soa_reply(const unsigned char * abuf,int alen,struct ares_soa_reply ** soa_out)44 ares_parse_soa_reply(const unsigned char *abuf, int alen,
45 struct ares_soa_reply **soa_out)
46 {
47 const unsigned char *aptr;
48 long len;
49 char *qname = NULL, *rr_name = NULL;
50 struct ares_soa_reply *soa = NULL;
51 int qdcount, ancount;
52 int status;
53
54 if (alen < HFIXEDSZ)
55 return ARES_EBADRESP;
56
57 /* parse message header */
58 qdcount = DNS_HEADER_QDCOUNT(abuf);
59 ancount = DNS_HEADER_ANCOUNT(abuf);
60 if (qdcount != 1 || ancount != 1)
61 return ARES_EBADRESP;
62 aptr = abuf + HFIXEDSZ;
63
64 /* query name */
65 status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
66 if (status != ARES_SUCCESS)
67 goto failed_stat;
68 aptr += len;
69
70 /* skip qtype & qclass */
71 if (aptr + QFIXEDSZ > abuf + alen)
72 goto failed;
73 aptr += QFIXEDSZ;
74
75 /* rr_name */
76 status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
77 if (status != ARES_SUCCESS)
78 goto failed_stat;
79 aptr += len;
80
81 /* skip rr_type, rr_class, rr_ttl, rr_rdlen */
82 if (aptr + RRFIXEDSZ > abuf + alen)
83 goto failed;
84 aptr += RRFIXEDSZ;
85
86 /* allocate result struct */
87 soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
88 if (!soa)
89 {
90 status = ARES_ENOMEM;
91 goto failed_stat;
92 }
93
94 /* nsname */
95 status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname, &len);
96 if (status != ARES_SUCCESS)
97 goto failed_stat;
98 aptr += len;
99
100 /* hostmaster */
101 status = ares__expand_name_for_response(aptr, abuf, alen, &soa->hostmaster, &len);
102 if (status != ARES_SUCCESS)
103 goto failed_stat;
104 aptr += len;
105
106 /* integer fields */
107 if (aptr + 5 * 4 > abuf + alen)
108 goto failed;
109 soa->serial = DNS__32BIT(aptr + 0 * 4);
110 soa->refresh = DNS__32BIT(aptr + 1 * 4);
111 soa->retry = DNS__32BIT(aptr + 2 * 4);
112 soa->expire = DNS__32BIT(aptr + 3 * 4);
113 soa->minttl = DNS__32BIT(aptr + 4 * 4);
114
115 ares_free(qname);
116 ares_free(rr_name);
117
118 *soa_out = soa;
119
120 return ARES_SUCCESS;
121
122 failed:
123 status = ARES_EBADRESP;
124
125 failed_stat:
126 ares_free_data(soa);
127 if (qname)
128 ares_free(qname);
129 if (rr_name)
130 ares_free(rr_name);
131 return status;
132 }
133
134