Added checksum calculations for events larger than 2^24 bytes

The checksums are now properly calculated for large events that span multiple
SQL packets.

server/modules/include/blr.h

@@ -424,6 +424,7 @@ typedef struct router_instance {
 	int			trx_safe;	/*< Detect and handle partial transactions */
 	int			pending_transaction; /*< Pending transaction */
 	enum blr_event_state master_event_state; /*< Packet read state */
+	uint32_t	stored_checksum; /*< The current value of the checksum */
 	REP_HEADER	stored_header; /*< Relication header of the event the master is sending */
 	uint64_t		last_safe_pos; /* last committed transaction */
 	char			binlog_name[BINLOG_FNAMELEN+1];

server/modules/include/mysql_client_server_protocol.h

@@ -70,6 +70,7 @@
 #define GW_MYSQL_READ 0
 #define GW_MYSQL_WRITE 1
 #define MYSQL_HEADER_LEN 4L
+#define MYSQL_CHECKSUM_LEN 4L
 
 #define GW_MYSQL_PROTOCOL_VERSION 10 // version is 10
 #define GW_MYSQL_HANDSHAKE_FILLER 0x00