#ifndef __MSGR_H
  #define __MSGR_H
  
  /*
   * Data types for message passing layer used by Ceph.
   */
  
  #define CEPH_MON_PORT    6789  /* default monitor port */
  
  /*
   * client-side processes will try to bind to ports in this
   * range, simply for the benefit of tools like nmap or wireshark
   * that would like to identify the protocol.
   */
  #define CEPH_PORT_FIRST  6789
  #define CEPH_PORT_START  6800  /* non-monitors start here */
  #define CEPH_PORT_LAST   6900
  
  /*
   * tcp connection banner.  include a protocol version. and adjust
   * whenever the wire protocol changes.  try to keep this string length
   * constant.
   */

  #define CEPH_BANNER "ceph v027"

  #define CEPH_BANNER_MAX_LEN 30
  
  
  /*
   * Rollover-safe type and comparator for 32-bit sequence numbers.
   * Comparator returns -1, 0, or 1.
   */
  typedef __u32 ceph_seq_t;
  
  static inline __s32 ceph_seq_cmp(__u32 a, __u32 b)
  {
         return (__s32)a - (__s32)b;
  }
  
  
  /*
   * entity_name -- logical name for a process participating in the
   * network, e.g. 'mds0' or 'osd3'.
   */
  struct ceph_entity_name {
  	__u8 type;      /* CEPH_ENTITY_TYPE_* */
  	__le64 num;
  } __attribute__ ((packed));

  #define CEPH_ENTITY_TYPE_MON    0x01
  #define CEPH_ENTITY_TYPE_MDS    0x02
  #define CEPH_ENTITY_TYPE_OSD    0x04
  #define CEPH_ENTITY_TYPE_CLIENT 0x08

  #define CEPH_ENTITY_TYPE_AUTH   0x20
  
  #define CEPH_ENTITY_TYPE_ANY    0xFF
  
  extern const char *ceph_entity_type_name(int type);

  
  /*
   * entity_addr -- network address
   */
  struct ceph_entity_addr {

  	__le32 type;
  	__le32 nonce;  /* unique id for process (e.g. pid) */

  	struct sockaddr_storage in_addr;
  } __attribute__ ((packed));

  struct ceph_entity_inst {
  	struct ceph_entity_name name;
  	struct ceph_entity_addr addr;
  } __attribute__ ((packed));
  
  
  /* used by message exchange protocol */
  #define CEPH_MSGR_TAG_READY         1  /* server->client: ready for messages */
  #define CEPH_MSGR_TAG_RESETSESSION  2  /* server->client: reset, try again */
  #define CEPH_MSGR_TAG_WAIT          3  /* server->client: wait for racing
  					  incoming connection */
  #define CEPH_MSGR_TAG_RETRY_SESSION 4  /* server->client + cseq: try again
  					  with higher cseq */
  #define CEPH_MSGR_TAG_RETRY_GLOBAL  5  /* server->client + gseq: try again
  					  with higher gseq */
  #define CEPH_MSGR_TAG_CLOSE         6  /* closing pipe */
  #define CEPH_MSGR_TAG_MSG           7  /* message */
  #define CEPH_MSGR_TAG_ACK           8  /* message ack */
  #define CEPH_MSGR_TAG_KEEPALIVE     9  /* just a keepalive byte! */
  #define CEPH_MSGR_TAG_BADPROTOVER  10  /* bad protocol version */

  #define CEPH_MSGR_TAG_BADAUTHORIZER 11 /* bad authorizer */

  #define CEPH_MSGR_TAG_FEATURES      12 /* insufficient features */

  
  
  /*
   * connection negotiation
   */
  struct ceph_msg_connect {

  	__le64 features;     /* supported feature bits */

  	__le32 host_type;    /* CEPH_ENTITY_TYPE_* */
  	__le32 global_seq;   /* count connections initiated by this host */
  	__le32 connect_seq;  /* count connections initiated in this session */
  	__le32 protocol_version;

  	__le32 authorizer_protocol;
  	__le32 authorizer_len;

  	__u8  flags;         /* CEPH_MSG_CONNECT_* */
  } __attribute__ ((packed));
  
  struct ceph_msg_connect_reply {
  	__u8 tag;

  	__le64 features;     /* feature bits for this session */

  	__le32 global_seq;
  	__le32 connect_seq;
  	__le32 protocol_version;

  	__le32 authorizer_len;

  	__u8 flags;
  } __attribute__ ((packed));
  
  #define CEPH_MSG_CONNECT_LOSSY  1  /* messages i send may be safely dropped */
  
  
  /*
   * message header
   */

  struct ceph_msg_header_old {

  	__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_inst src, orig_src;

  	__le32 reserved;

  	__le32 crc;       /* header crc32c */
  } __attribute__ ((packed));

  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));

  #define CEPH_MSG_PRIO_LOW     64
  #define CEPH_MSG_PRIO_DEFAULT 127
  #define CEPH_MSG_PRIO_HIGH    196
  #define CEPH_MSG_PRIO_HIGHEST 255
  
  /*
   * follows data payload
   */
  struct ceph_msg_footer {
  	__le32 front_crc, middle_crc, data_crc;
  	__u8 flags;
  } __attribute__ ((packed));
  
  #define CEPH_MSG_FOOTER_COMPLETE  (1<<0)   /* msg wasn't aborted */
  #define CEPH_MSG_FOOTER_NOCRC     (1<<1)   /* no data crc */
  
  
  #endif