45 lines
991 B
C
45 lines
991 B
C
#include <resolv.h>
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#include <string.h>
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#include <time.h>
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int __res_mkquery(int op, const char *dname, int class, int type,
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const unsigned char *data, int datalen,
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const unsigned char *newrr, unsigned char *buf, int buflen)
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{
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int id, i, j;
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unsigned char q[280];
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struct timespec ts;
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size_t l = strnlen(dname, 255);
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int n;
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if (l && dname[l-1]=='.') l--;
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n = 17+l+!!l;
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if (l>253 || buflen<n || op>15u || class>255u || type>255u)
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return -1;
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/* Construct query template - ID will be filled later */
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memset(q, 0, n);
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q[2] = op*8 + 1;
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q[3] = 32; /* AD */
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q[5] = 1;
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memcpy((char *)q+13, dname, l);
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for (i=13; q[i]; i=j+1) {
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for (j=i; q[j] && q[j] != '.'; j++);
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if (j-i-1u > 62u) return -1;
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q[i-1] = j-i;
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}
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q[i+1] = type;
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q[i+3] = class;
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/* Make a reasonably unpredictable id */
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clock_gettime(CLOCK_REALTIME, &ts);
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id = ts.tv_nsec + ts.tv_nsec/65536UL & 0xffff;
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q[0] = id/256;
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q[1] = id;
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memcpy(buf, q, n);
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return n;
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}
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weak_alias(__res_mkquery, res_mkquery);
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