less magic numbers and generic send function

network.h

@@ -1,9 +1,14 @@
 #define SERVER "::1"
 #define PORT 49000
 
-#define COMMAND_BUFFER 256
+#define SEND_BUFFER 256
 
-char* printable(char *str);
-int sendCommand(int sock, char *cmd);
+#define DGRAM_MSG_LENGTH 4
+#define DGRAM_NULL_LENGTH 1
+
+extern const int DGRAM_MSG_START;
+extern const int DGRAM_PAYLOAD_START;
+
+int sendToXPlane(int sock, char *msg, char *payload);
 int connectXPlane(char *addr, int port);
 int disconnectXPlane(int sock);