1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/* Copyright 1998 by the Massachusetts Institute of Technology.
* Copyright (C) 2012 Marko Kreen <markokr@gmail.com>
*
* 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_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 "ares.h"
#include "ares_dns.h"
#include "ares_data.h"
#include "ares_private.h"
int
ares_parse_soa_reply(const unsigned char *abuf, int alen,
struct ares_soa_reply **soa_out)
{
const unsigned char *aptr;
long len;
char *qname = NULL, *rr_name = NULL;
struct ares_soa_reply *soa = NULL;
int qdcount, ancount, qclass;
int status, i, rr_type, rr_class, rr_len;
int ttl;
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* parse message header */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_EBADRESP;
aptr = abuf + HFIXEDSZ;
/* query name */
status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
qclass = DNS_QUESTION_TYPE(aptr);
/* skip qtype & qclass */
if (aptr + QFIXEDSZ > abuf + alen)
goto failed;
aptr += QFIXEDSZ;
/* qclass of SOA with multiple answers */
if (qclass == T_SOA && ancount > 1)
goto failed;
/* examine all the records, break and return if found soa */
for (i = 0; i < ancount; i++)
{
rr_name = NULL;
status = ares__expand_name_for_response (aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
if ( aptr + RRFIXEDSZ > abuf + alen )
{
ares_free(rr_name);
status = ARES_EBADRESP;
goto failed_stat;
}
rr_type = DNS_RR_TYPE( aptr );
rr_class = DNS_RR_CLASS( aptr );
rr_len = DNS_RR_LEN( aptr );
ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
ares_free(rr_name);
status = ARES_EBADRESP;
goto failed_stat;
}
if ( rr_class == C_IN && rr_type == T_SOA )
{
/* allocate result struct */
soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
if (!soa)
{
ares_free(rr_name);
status = ARES_ENOMEM;
goto failed_stat;
}
/* nsname */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname,
&len);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
/* hostmaster */
status = ares__expand_name_for_response(aptr, abuf, alen,
&soa->hostmaster, &len);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
goto failed_stat;
}
aptr += len;
/* integer fields */
if (aptr + 5 * 4 > abuf + alen)
{
ares_free(rr_name);
goto failed;
}
soa->serial = DNS__32BIT(aptr + 0 * 4);
soa->refresh = DNS__32BIT(aptr + 1 * 4);
soa->retry = DNS__32BIT(aptr + 2 * 4);
soa->expire = DNS__32BIT(aptr + 3 * 4);
soa->minttl = DNS__32BIT(aptr + 4 * 4);
soa->ttl = ttl;
ares_free(qname);
ares_free(rr_name);
*soa_out = soa;
return ARES_SUCCESS;
}
aptr += rr_len;
ares_free(rr_name);
if (aptr > abuf + alen)
goto failed_stat;
}
/* no SOA record found */
status = ARES_EBADRESP;
goto failed_stat;
failed:
status = ARES_EBADRESP;
failed_stat:
if (soa)
ares_free_data(soa);
if (qname)
ares_free(qname);
return status;
}
|
