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 *),void * ctx)4 int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), 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 if (qdcount+ancount > 64) return -1;
16 while (qdcount--) {
17 while (p-r < rlen && *p-1U < 127) p++;
18 if (*p>193 || (*p==193 && p[1]>254) || p>r+rlen-6)
19 return -1;
20 p += 5 + !!*p;
21 }
22 while (ancount--) {
23 while (p-r < rlen && *p-1U < 127) p++;
24 if (*p>193 || (*p==193 && p[1]>254) || p>r+rlen-6)
25 return -1;
26 p += 1 + !!*p;
27 len = p[8]*256 + p[9];
28 if (p+len > r+rlen) return -1;
29 if (callback(ctx, p[1], p+10, len, r) < 0) return -1;
30 p += 10 + len;
31 }
32 return 0;
33 }
34