64 lines
1.2 KiB
Plaintext
64 lines
1.2 KiB
Plaintext
module DNS_Helpers {
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private function f_strchr(charstring s, char c) return integer {
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var integer i;
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for (i := 0; i < lengthof(s); i := i+1) {
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if (s[i] == c) {
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return i;
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}
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}
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return -1;
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}
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private function f_dns_enc_label(charstring str) return octetstring {
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var octetstring ret;
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ret[0] := int2oct(lengthof(str), 1);
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return ret & char2oct(str);
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}
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function f_enc_dns_hostname(charstring str) return octetstring {
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var octetstring ret := ''O;
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while (lengthof(str) > 0) {
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var integer dot_idx;
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var octetstring lbl;
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dot_idx := f_strchr(str, ".");
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if (dot_idx >= 0) {
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/* there is another dot */
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lbl := f_dns_enc_label(substr(str, 0, dot_idx));
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str := substr(str, dot_idx+1, lengthof(str)-dot_idx-1);
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} else {
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/* no more dot */
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lbl := f_dns_enc_label(str);
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str := "";
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}
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ret := ret & lbl;
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}
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return ret;
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}
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function f_dec_dns_hostname(octetstring inp) return charstring {
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var charstring ret := "";
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while (lengthof(inp) > 0) {
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var integer label_len;
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var charstring lbl;
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label_len := oct2int(substr(inp, 0, 1));
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lbl := oct2char(substr(inp, 1, label_len));
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inp := substr(inp, 1+label_len, lengthof(inp)-1-label_len);
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ret := ret & lbl;
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if (lengthof(inp) > 0) {
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ret := ret & ".";
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}
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}
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return ret;
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}
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}
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