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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/*
** Copyright 1998 - 2004 Double Precision, Inc.
** See COPYING for distribution information.
*/
#include "rfc1035.h"
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include "rfc1035_res.h"
static const char rcsid[]="$Id: rfc1035qa.c,v 1.9 2005/06/24 17:47:33 mrsam Exp $";
/* Convenient function to do forward IP lookup */
#if RFC1035_IPV6
static int rfc1035_a_ipv4(struct rfc1035_res *res,
const char *name, struct in_addr **iaptr, unsigned *iasize)
#else
int rfc1035_a(struct rfc1035_res *res,
const char *name, RFC1035_ADDR **iaptr, unsigned *iasize)
#endif
{
struct rfc1035_reply *reply;
int n, o;
char namebuf[RFC1035_MAXNAMESIZE+1];
namebuf[0]=0;
strncat(namebuf, name, RFC1035_MAXNAMESIZE);
*iasize=0;
if (rfc1035_resolve_cname(res,
RFC1035_RESOLVE_RECURSIVE, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, &reply, 0) < 0 ||
reply == 0 ||
(n=rfc1035_replysearch_an( res, reply, namebuf, RFC1035_TYPE_A,
RFC1035_CLASS_IN, 0)) < 0)
{
if (reply && reply->rcode != RFC1035_RCODE_NXDOMAIN &&
reply->rcode != RFC1035_RCODE_NOERROR)
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (1); /* soft error */
}
if (reply) rfc1035_replyfree(reply);
errno=ENOENT;
return (-1); /* hard error */
}
for (o=n; o >= 0; o=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, o+1))
++*iasize;
if ( *iasize == 0 )
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (-1);
}
if ( (*iaptr=(struct in_addr *)malloc(sizeof(**iaptr)* *iasize)) == 0)
{
rfc1035_replyfree(reply);
return (-1);
}
for (*iasize=0; n >= 0; n=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_A, RFC1035_CLASS_IN, n+1))
{
(*iaptr)[*iasize]= reply->allrrs[n]->rr.inaddr;
++*iasize;
}
rfc1035_replyfree(reply);
return (0);
}
#if RFC1035_IPV6
/*
** The IPv6 version issues two queries - for both A and AAAA records,
** then maps any A record to IPv6.
**
** If we get back both an AAAA for the IPv4-mapped address, and the
** A record itself, ignore the dupe.
*/
static int we_have_that_ipv4(struct in6_addr in6,
const struct in_addr *ia4ptr,
unsigned ia4len)
{
char buf[INET6_ADDRSTRLEN];
const char *p;
struct in_addr in4;
unsigned i;
if (!IN6_IS_ADDR_V4MAPPED((&in6))) return (0); /* Not an IPv4 addy */
if (inet_ntop(AF_INET6, &in6, buf, sizeof(buf)) == 0)
return (0); /* WTF??? */
if ((p=strrchr(buf, ':')) != 0)
++p;
else
p=buf;
rfc1035_aton_ipv4(p, &in4);
for (i=0; i<ia4len; i++)
if (ia4ptr[i].s_addr == in4.s_addr) return (1);
return (0);
}
int rfc1035_a(struct rfc1035_res *res,
const char *name, struct in6_addr **iaptr, unsigned *iasize)
{
struct rfc1035_reply *reply;
int n, o;
char namebuf[RFC1035_MAXNAMESIZE+1];
int enotfound=0;
struct in_addr *ia4ptr;
unsigned ia4len;
unsigned k;
n=rfc1035_a_ipv4(res, name, &ia4ptr, &ia4len);
if (n > 0) return (n);
if (n < 0)
{
if (errno != ENOENT) return (n);
ia4len=0;
ia4ptr=0;
enotfound=1;
}
namebuf[0]=0;
strncat(namebuf, name, RFC1035_MAXNAMESIZE);
*iasize=ia4len;
reply=0;
/*
** Resist the temptation to stick in "ia4len > 0 &&", below. Why?
** A) We get a connection from an IPv6 address.
** B) Spam check: the IP address must resolve backwards and forwards.
** C) There are IPv4 records for the same hostname as well.
** D) This sux.
*/
if (rfc1035_resolve_cname(res,
RFC1035_RESOLVE_RECURSIVE, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, &reply, 0) < 0 ||
reply == 0 ||
(n=rfc1035_replysearch_an( res, reply, namebuf,
RFC1035_TYPE_AAAA,
RFC1035_CLASS_IN, 0)) < 0)
{
if (reply && reply->rcode != RFC1035_RCODE_NXDOMAIN &&
reply->rcode != RFC1035_RCODE_NOERROR &&
*iasize == 0)
/* Unfortunately this is necessary. Some swervers
** return a TEMPFAIL for AAAA queries.
*/
{
errno=EAGAIN;
rfc1035_replyfree(reply);
if (ia4len)
free(ia4ptr);
return (1); /* soft error */
}
if (reply) rfc1035_replyfree(reply);
if (enotfound)
return (-1);
enotfound=1;
reply=0;
n= -1;
}
else
{
for (o=n; o >= 0; o=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, o+1))
{
if (we_have_that_ipv4(reply->allrrs[n]->rr.in6addr,
ia4ptr, ia4len))
continue;
++*iasize;
}
}
if ( *iasize == 0 && enotfound)
{
if (ia4len)
free(ia4ptr);
errno=ENOENT;
return (-1);
}
if ( *iasize == 0 )
{
errno=EAGAIN;
rfc1035_replyfree(reply);
return (-1);
}
if ( (*iaptr=(struct in6_addr *)malloc(sizeof(**iaptr)* *iasize)) == 0)
{
rfc1035_replyfree(reply);
return (-1);
}
for (*iasize=0; n >= 0; n=rfc1035_replysearch_an(res, reply, namebuf,
RFC1035_TYPE_AAAA, RFC1035_CLASS_IN, n+1))
{
if (we_have_that_ipv4(reply->allrrs[n]->rr.in6addr,
ia4ptr, ia4len))
continue;
(*iaptr)[*iasize]= reply->allrrs[n]->rr.in6addr;
++*iasize;
}
for (k=0; k<ia4len; k++)
{
char buf[INET6_ADDRSTRLEN];
strcpy(buf, "::ffff:");
rfc1035_ntoa_ipv4( &ia4ptr[k], buf+sizeof("::ffff:")-1);
if (inet_pton( AF_INET6, buf, (*iaptr)+ *iasize) <= 0)
memset( (*iaptr)+ *iasize, 0, sizeof(*iaptr));
++*iasize;
}
if (ia4len)
free (ia4ptr);
rfc1035_replyfree(reply);
return (0);
}
#endif
|
