1 #include <resolv.h>
2 #include <string.h>
3 #include <time.h>
4
__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)5 int __res_mkquery(int op, const char *dname, int class, int type,
6 const unsigned char *data, int datalen,
7 const unsigned char *newrr, unsigned char *buf, int buflen)
8 {
9 int id, i, j;
10 unsigned char q[280];
11 struct timespec ts;
12 size_t l = strnlen(dname, 255);
13 int n;
14
15 if (l && dname[l-1]=='.') l--;
16 n = 17+l+!!l;
17 if (l>253 || buflen<n || op>15u || class>255u || type>255u)
18 return -1;
19
20 /* Construct query template - ID will be filled later */
21 memset(q, 0, n);
22 q[2] = op*8 + 1;
23 q[5] = 1;
24 memcpy((char *)q+13, dname, l);
25 for (i=13; q[i]; i=j+1) {
26 for (j=i; q[j] && q[j] != '.'; j++);
27 if (j-i-1u > 62u) return -1;
28 q[i-1] = j-i;
29 }
30 q[i+1] = type;
31 q[i+3] = class;
32
33 /* Make a reasonably unpredictable id */
34 clock_gettime(CLOCK_REALTIME, &ts);
35 id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff;
36 q[0] = id/256;
37 q[1] = id;
38
39 memcpy(buf, q, n);
40 return n;
41 }
42
43 weak_alias(__res_mkquery, res_mkquery);
44