update code

dns.h

@@ -0,0 +1,39 @@
+#ifndef _DNS_HEAD_H
+#define _DNS_HEAD_H
+
+#pragma pack(push, 1)
+
+struct dns_head {
+    unsigned short id; // identification number
+    unsigned char rd : 1; // recursion desired
+    unsigned char tc : 1; // truncated message
+    unsigned char aa : 1; // authoritive answer
+    unsigned char opcode : 4; // purpose of message
+    unsigned char qr : 1; // query/response flag
+    unsigned char rcode : 4; // response code
+    unsigned char cd : 1; // checking disabled
+    unsigned char ad : 1; // authenticated data
+    unsigned char z : 1; // its z! reserved
+    unsigned char ra : 1; // recursion available
+    unsigned short qd_count; // number of question entries
+    unsigned short an_count; // number of answer entries
+    unsigned short ns_count; // number of authority entries
+    unsigned short nr_count; // number of resource entries
+};
+
+struct dns_qds {
+    unsigned short type;
+    unsigned short classes;
+};
+
+struct dns_rrs {
+    unsigned short type;
+    unsigned short classes;
+    unsigned int ttl;
+    unsigned short rd_length;
+    char rd_data[0];
+};
+
+#pragma pack(pop)
+
+#endif