| #include <string.h> |
| |
| int __dns_parse(const unsigned char* r, int rlen, |
| int (*callback)(void*, int, const void*, int, const void*), void* ctx) { |
| int qdcount, ancount; |
| const unsigned char* p; |
| int len; |
| |
| if (rlen < 12) |
| return -1; |
| if ((r[3] & 15)) |
| return 0; |
| p = r + 12; |
| qdcount = r[4] * 256 + r[5]; |
| ancount = r[6] * 256 + r[7]; |
| if (qdcount + ancount > 64) |
| return -1; |
| while (qdcount--) { |
| while (p - r < rlen && *p - 1U < 127) |
| p++; |
| if (*p > 193 || (*p == 193 && p[1] > 254) || p > r + rlen - 6) |
| return -1; |
| p += 5 + !!*p; |
| } |
| while (ancount--) { |
| while (p - r < rlen && *p - 1U < 127) |
| p++; |
| if (*p > 193 || (*p == 193 && p[1] > 254) || p > r + rlen - 6) |
| return -1; |
| p += 1 + !!*p; |
| len = p[8] * 256 + p[9]; |
| if (p + len > r + rlen) |
| return -1; |
| if (callback(ctx, p[1], p + 10, len, r) < 0) |
| return -1; |
| p += 10 + len; |
| } |
| return 0; |
| } |
