source: asp3_tinet_ecnl_rx/trunk/musl-1.1.18/src/network/dns_parse.c@ 337

#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;
}