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
|
/**************************************************************************
* ns_ncache.c
* author: anant kumar
* last modification: March 17, 1993
*
* implements negative caching
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <syslog.h>
#include <errno.h>
#include <stdio.h>
#include <resolv.h>
#include "named.h"
#ifdef NCACHE
#define BOUNDS_CHECK(ptr, count) \
do { \
if ((ptr) + (count) > eom) { \
return; \
} \
} while (0)
void
cache_n_resp(msg, msglen)
u_char *msg;
int msglen;
{
register struct databuf *dp;
HEADER *hp;
u_char *cp, *eom, *rdatap;
char dname[MAXDNAME];
int n;
int type, class;
#ifdef VALIDATE
int Vcode;
#endif
int flags;
u_int dlen;
nameserIncr(from_addr.sin_addr, nssRcvdNXD);
hp = (HEADER *)msg;
cp = msg+HFIXEDSZ;
eom = msg + msglen;
n = dn_expand(msg, eom, cp, dname, sizeof dname);
if (n < 0) {
dprintf(1, (ddt, "Query expand name failed:cache_n_resp\n"));
hp->rcode = FORMERR;
return;
}
cp += n;
BOUNDS_CHECK(cp, 2 * INT16SZ);
GETSHORT(type, cp);
GETSHORT(class, cp);
dprintf(1, (ddt,
"ncache: dname %s, type %d, class %d\n",
dname, type, class));
#ifdef VALIDATE
Vcode = validate(dname, dname, &from_addr, type, class, NULL, 0,
hp->rcode == NXDOMAIN ? NXDOMAIN : NOERROR_NODATA);
if (Vcode == INVALID || Vcode == VALID_NO_CACHE) {
/*Valid_no_cache should never occur but doesn't hurt to check*/
return;
}
#endif
#ifdef RETURNSOA
if (hp->nscount) {
u_int32_t ttl;
u_int16_t atype;
u_char *tp = cp;
u_char *cp1;
u_char data[MAXDNAME*2 + INT32SZ*5];
size_t len = sizeof data;
/* we store NXDOMAIN as T_SOA regardless of the query type */
if (hp->rcode == NXDOMAIN)
type = T_SOA;
/* store their SOA record */
n = dn_skipname(tp, eom);
if (n < 0) {
dprintf(3, (ddt, "ncache: form error\n"));
return;
}
tp += n;
BOUNDS_CHECK(tp, 3 * INT16SZ + INT32SZ);
GETSHORT(atype, tp); /* type */
if (atype != T_SOA) {
dprintf(3, (ddt,
"ncache: type (%d) != T_SOA\n",atype));
goto no_soa;
}
tp += INT16SZ; /* class */
GETLONG(ttl, tp); /* ttl */
GETSHORT(dlen, tp); /* dlen */
BOUNDS_CHECK(tp, dlen);
rdatap = tp;
/* origin */
n = dn_expand(msg, eom, tp, (char*)data, len);
if (n < 0) {
dprintf(3, (ddt, "ncache: form error 2\n"));
return;
}
tp += n;
n = strlen((char*)data) + 1;
cp1 = data + n;
len -= n;
/* mail */
n = dn_expand(msg, msg + msglen, tp, (char*)cp1, len);
if (n < 0) {
dprintf(3, (ddt, "ncache: form error 2\n"));
return;
}
tp += n;
n = strlen((char*)cp1) + 1;
cp1 += n;
len -= n;
n = 5 * INT32SZ;
BOUNDS_CHECK(tp, n);
bcopy(tp, cp1, n);
/* serial, refresh, retry, expire, min */
cp1 += n;
len -= n;
tp += n;
if (tp != rdatap + dlen) {
dprintf(3, (ddt, "ncache: form error 2\n"));
return;
}
/* store the zone of the soa record */
n = dn_expand(msg, msg + msglen, cp, (char*)cp1, len);
if (n < 0) {
dprintf(3, (ddt, "ncache: form error 2\n"));
return;
}
n = strlen((char*)cp1) + 1;
cp1 += n;
dp = savedata(class, type, MIN(ttl, NTTL) + tt.tv_sec, data,
cp1 - data);
} else {
no_soa:
#endif
dp = savedata(class, type, NTTL + tt.tv_sec, NULL, 0);
#ifdef RETURNSOA
}
#endif
dp->d_zone = DB_Z_CACHE;
dp->d_cred = hp->aa ? DB_C_AUTH : DB_C_ANSWER;
dp->d_clev = 0;
if(hp->rcode == NXDOMAIN) {
dp->d_rcode = NXDOMAIN;
flags = DB_NODATA|DB_NOTAUTH|DB_NOHINTS;
} else {
dp->d_rcode = NOERROR_NODATA;
flags = DB_NOTAUTH|DB_NOHINTS;
}
if ((n = db_update(dname, dp, dp, flags, hashtab)) != OK) {
dprintf(1, (ddt,
"db_update failed return value:%d, cache_n_resp()\n",
n));
db_free(dp);
return;
}
dprintf(4, (ddt,
"ncache succeeded: [%s %s %s] rcode:%d ttl:%ld\n",
dname, p_type(type), p_class(class),
dp->d_rcode, (long)(dp->d_ttl-tt.tv_sec)));
return;
}
#endif /*NCACHE*/
|
