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