source:
EcnlProtoTool/trunk/musl-1.1.18/src/network/dns_parse.c
Last change on this file was 444, checked in by , 4 years ago | |
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File size: 804 bytes |
Rev | Line | |
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[444] | 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 | ||
9 | if (rlen<12) return -1; | |
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++; | |
17 | if (*p>193 || (*p==193 && p[1]>254) || 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>193 || (*p==193 && p[1]>254) || p>r+rlen-6) | |
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 | } |
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