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
|
#include <resolv.h>
#include <string.h>
#include <time.h>
int __res_mkquery(int op, const char *dname, int class, int type,
const unsigned char *data, int datalen,
const unsigned char *newrr, unsigned char *buf, int buflen)
{
int id, i, j;
unsigned char q[280];
struct timespec ts;
size_t l = strnlen(dname, 255);
int n;
if (l && dname[l-1]=='.') l--;
n = 17+l+!!l;
if (l>253 || buflen<n || op>15u || class>255u || type>255u)
return -1;
/* Construct query template - ID will be filled later */
memset(q, 0, n);
q[2] = op*8 + 1;
q[3] = 32; /* AD */
q[5] = 1;
memcpy((char *)q+13, dname, l);
for (i=13; q[i]; i=j+1) {
for (j=i; q[j] && q[j] != '.'; j++);
if (j-i-1u > 62u) return -1;
q[i-1] = j-i;
}
q[i+1] = type;
q[i+3] = class;
/* Make a reasonably unpredictable id */
clock_gettime(CLOCK_REALTIME, &ts);
id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff;
q[0] = id/256;
q[1] = id;
memcpy(buf, q, n);
return n;
}
weak_alias(__res_mkquery, res_mkquery);
|
