refactor initial code and accept a UDP request

include/dns_packet_buffer.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <stddef.h>
+
+#define PACKET_BUFFER_SIZE 512
+
+struct DNSPacketBuffer {
+    char buf[PACKET_BUFFER_SIZE];
+    size_t pos;
+};
+
+struct DNSPacketBuffer *new_dns_packet_buffer();
+
+struct DNSPacketHeader *dns_header(struct DNSPacketBuffer);

include/dns_packets.h

@@ -2,7 +2,7 @@
 #include <stddef.h>
 
 
-struct Header {
+struct DNSPacketHeader {
     /*
      * ID (Packet Identifier)
      * a random ID is assigned to query packets.

include/dns_request.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include "dns_packets.h"
+
+struct DNSRequest {
+    struct DNSPacketHeader header;
+};

include/packet_buffer.h

@@ -1,11 +0,0 @@
-#pragma once
-#include <stddef.h>
-
-#define PACKET_BUFFER_SIZE 512
-
-struct PacketBuffer {
-    char buf[PACKET_BUFFER_SIZE];
-    size_t pos;
-};
-
-struct PacketBuffer *new_packet_buffer();

include/udp_server.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#define UDP_PORT 53
+
+int start_server();