extern int IPv4_RegisterCallback(int ID, tIPCallback Callback);
extern Uint16 IPv4_Checksum(const void *Buf, size_t Length);
extern Uint32 IPv4_Netmask(int FixedBits);
extern int IPv4_RegisterCallback(int ID, tIPCallback Callback);
extern Uint16 IPv4_Checksum(const void *Buf, size_t Length);
extern Uint32 IPv4_Netmask(int FixedBits);