1 #include <string.h>
2 #include "lookup.h"
3
__dns_parse(const unsigned char * r,int rlen,int (* callback)(void *,int,const void *,int,const void *,int),void * ctx)4 int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *, int), void *ctx)
5 {
6 int qdcount, ancount;
7 const unsigned char *p;
8 int len;
9
10 if (rlen<12) return -1;
11 if ((r[3]&15)) return 0;
12 p = r+12;
13 qdcount = r[4]*256 + r[5];
14 ancount = r[6]*256 + r[7];
15 while (qdcount--) {
16 while (p-r < rlen && *p-1U < 127) p++;
17 if (p>r+rlen-6)
18 return -1;
19 p += 5 + !!*p;
20 }
21 while (ancount--) {
22 while (p-r < rlen && *p-1U < 127) p++;
23 if (p>r+rlen-12)
24 return -1;
25 p += 1 + !!*p;
26 len = p[8]*256 + p[9];
27 if (len+10 > r+rlen-p) return -1;
28 if (callback(ctx, p[1], p+10, len, r, rlen) < 0) return -1;
29 p += 10 + len;
30 }
31 return 0;
32 }
33