Rich Felker | 3330198 | 2014-06-02 04:47:45 -0400 | [diff] [blame] | 1 | #include <string.h> |
| 2 | |
| 3 | int __dns_parse(const unsigned char *r, int rlen, int (*callback)(void *, int, const void *, int, const void *), void *ctx) |
| 4 | { |
| 5 | int qdcount, ancount; |
| 6 | const unsigned char *p; |
| 7 | int len; |
| 8 | |
Rich Felker | ac2a789 | 2014-06-03 01:43:29 -0400 | [diff] [blame] | 9 | if (rlen<12) return -1; |
Rich Felker | 3330198 | 2014-06-02 04:47:45 -0400 | [diff] [blame] | 10 | if ((r[3]&15)) return 0; |
| 11 | p = r+12; |
| 12 | qdcount = r[4]*256 + r[5]; |
| 13 | ancount = r[6]*256 + r[7]; |
| 14 | if (qdcount+ancount > 64) return -1; |
| 15 | while (qdcount--) { |
| 16 | while (p-r < rlen && *p-1U < 127) p++; |
Rich Felker | ac2a789 | 2014-06-03 01:43:29 -0400 | [diff] [blame] | 17 | if (*p>193 || (*p==193 && p[1]>254) || p>r+rlen-6) |
Rich Felker | 3330198 | 2014-06-02 04:47:45 -0400 | [diff] [blame] | 18 | return -1; |
| 19 | p += 5 + !!*p; |
| 20 | } |
| 21 | while (ancount--) { |
| 22 | while (p-r < rlen && *p-1U < 127) p++; |
Rich Felker | ac2a789 | 2014-06-03 01:43:29 -0400 | [diff] [blame] | 23 | if (*p>193 || (*p==193 && p[1]>254) || p>r+rlen-6) |
Rich Felker | 3330198 | 2014-06-02 04:47:45 -0400 | [diff] [blame] | 24 | return -1; |
| 25 | p += 1 + !!*p; |
| 26 | len = p[8]*256 + p[9]; |
| 27 | if (p+len > r+rlen) return -1; |
| 28 | if (callback(ctx, p[1], p+10, len, r) < 0) return -1; |
| 29 | p += 10 + len; |
| 30 | } |
| 31 | return 0; |
| 32 | } |