+struct ceph_msg_header {
+ __le64 seq; /* message seq# for this session */
+ __le64 tid; /* transaction id */
+ __le16 type; /* message type */
+ __le16 priority; /* priority. higher value == higher priority */
+ __le16 version; /* version of message encoding */
+
+ __le32 front_len; /* bytes in main payload */
+ __le32 middle_len;/* bytes in middle payload */
+ __le32 data_len; /* bytes of data payload */
+ __le16 data_off; /* sender: include full offset;
+ receiver: mask against ~PAGE_MASK */
+
+ struct ceph_entity_name src;
+ __le32 reserved;
+ __le32 crc; /* header crc32c */
+} __attribute__ ((packed));
+