Features on packet design

All messages structures are defined as union of struct. It therefore contains no string or unstring operations during packets transmission.

typedef unsigned int   	MAGICNUM;
typedef unsigned short 	MSGLEN;
typedef unsigned short 	MSGID;
typedef char 		NAME[11];
typedef char		PASSWORD[14];
typedef unsigned char   PLAYERID;
typedef int		VMONEY;
typedef unsigned short	ERRMSGID;

typedef struct {

   struct {
      MAGICNUM	magic_num;
      MSGLEN	len;
      MSGID	id;
   } header;

   union {

     union {
        struct {
           NAME		player_name; 
           PASSWORD	player_password;
        } request;
        
        struct {
           NAME		player_name;
           PLAYERID	player_id;
           VMONEY	vmoney;
        } accept;

        struct {
           NAME		player_name;
           ERRMSGID	error_msg;
        } reject;
           
     } login;

   /* Other message removed */
   
   };

} TIN9NETMSG;

Since all packets are transmitted in the same platform of machines, no byte ordering has been considered so far. However, we have made the provision that byte ordering can be added by just modifying the routine netcom.c without affecting any other modules of the program.

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