drivers/block/drbd/drbd_protocol.h - kernel/quantenna - Git at Google

 #ifndef __DRBD_PROTOCOL_H
 #define __DRBD_PROTOCOL_H

 enum drbd_packet {
 	/* receiver (data socket) */
 	P_DATA		      = 0x00,
 	P_DATA_REPLY	      = 0x01, /* Response to P_DATA_REQUEST */
 	P_RS_DATA_REPLY	      = 0x02, /* Response to P_RS_DATA_REQUEST */
 	P_BARRIER	      = 0x03,
 	P_BITMAP	      = 0x04,
 	P_BECOME_SYNC_TARGET  = 0x05,
 	P_BECOME_SYNC_SOURCE  = 0x06,
 	P_UNPLUG_REMOTE	      = 0x07, /* Used at various times to hint the peer */
 	P_DATA_REQUEST	      = 0x08, /* Used to ask for a data block */
 	P_RS_DATA_REQUEST     = 0x09, /* Used to ask for a data block for resync */
 	P_SYNC_PARAM	      = 0x0a,
 	P_PROTOCOL	      = 0x0b,
 	P_UUIDS		      = 0x0c,
 	P_SIZES		      = 0x0d,
 	P_STATE		      = 0x0e,
 	P_SYNC_UUID	      = 0x0f,
 	P_AUTH_CHALLENGE      = 0x10,
 	P_AUTH_RESPONSE	      = 0x11,
 	P_STATE_CHG_REQ	      = 0x12,

 	/* (meta socket) */
 	P_PING		      = 0x13,
 	P_PING_ACK	      = 0x14,
 	P_RECV_ACK	      = 0x15, /* Used in protocol B */
 	P_WRITE_ACK	      = 0x16, /* Used in protocol C */
 	P_RS_WRITE_ACK	      = 0x17, /* Is a P_WRITE_ACK, additionally call set_in_sync(). */
 	P_SUPERSEDED	      = 0x18, /* Used in proto C, two-primaries conflict detection */
 	P_NEG_ACK	      = 0x19, /* Sent if local disk is unusable */
 	P_NEG_DREPLY	      = 0x1a, /* Local disk is broken... */
 	P_NEG_RS_DREPLY	      = 0x1b, /* Local disk is broken... */
 	P_BARRIER_ACK	      = 0x1c,
 	P_STATE_CHG_REPLY     = 0x1d,

 	/* "new" commands, no longer fitting into the ordering scheme above */

 	P_OV_REQUEST	      = 0x1e, /* data socket */
 	P_OV_REPLY	      = 0x1f,
 	P_OV_RESULT	      = 0x20, /* meta socket */
 	P_CSUM_RS_REQUEST     = 0x21, /* data socket */
 	P_RS_IS_IN_SYNC	      = 0x22, /* meta socket */
 	P_SYNC_PARAM89	      = 0x23, /* data socket, protocol version 89 replacement for P_SYNC_PARAM */
 	P_COMPRESSED_BITMAP   = 0x24, /* compressed or otherwise encoded bitmap transfer */
 	/* P_CKPT_FENCE_REQ      = 0x25, * currently reserved for protocol D */
 	/* P_CKPT_DISABLE_REQ    = 0x26, * currently reserved for protocol D */
 	P_DELAY_PROBE         = 0x27, /* is used on BOTH sockets */
 	P_OUT_OF_SYNC         = 0x28, /* Mark as out of sync (Outrunning), data socket */
 	P_RS_CANCEL           = 0x29, /* meta: Used to cancel RS_DATA_REQUEST packet by SyncSource */
 	P_CONN_ST_CHG_REQ     = 0x2a, /* data sock: Connection wide state request */
 	P_CONN_ST_CHG_REPLY   = 0x2b, /* meta sock: Connection side state req reply */
 	P_RETRY_WRITE	      = 0x2c, /* Protocol C: retry conflicting write request */
 	P_PROTOCOL_UPDATE     = 0x2d, /* data sock: is used in established connections */
         /* 0x2e to 0x30 reserved, used in drbd 9 */

 	/* REQ_DISCARD. We used "discard" in different contexts before,
 	 * which is why I chose TRIM here, to disambiguate. */
 	P_TRIM                = 0x31,

 	P_MAY_IGNORE	      = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
 	P_MAX_OPT_CMD	      = 0x101,

 	/* special command ids for handshake */

 	P_INITIAL_META	      = 0xfff1, /* First Packet on the MetaSock */
 	P_INITIAL_DATA	      = 0xfff2, /* First Packet on the Socket */

 	P_CONNECTION_FEATURES = 0xfffe	/* FIXED for the next century! */
 };

 #ifndef __packed
 #define __packed __attribute__((packed))
 #endif

 /* This is the layout for a packet on the wire.
  * The byteorder is the network byte order.
  *     (except block_id and barrier fields.
  *	these are pointers to local structs
  *	and have no relevance for the partner,
  *	which just echoes them as received.)
  *
  * NOTE that the payload starts at a long aligned offset,
  * regardless of 32 or 64 bit arch!
  */
 struct p_header80 {
 	u32	  magic;
 	u16	  command;
 	u16	  length;	/* bytes of data after this header */
 } __packed;

 /* Header for big packets, Used for data packets exceeding 64kB */
 struct p_header95 {
 	u16	  magic;	/* use DRBD_MAGIC_BIG here */
 	u16	  command;
 	u32	  length;
 } __packed;

 struct p_header100 {
 	u32	  magic;
 	u16	  volume;
 	u16	  command;
 	u32	  length;
 	u32	  pad;
 } __packed;

 /* these defines must not be changed without changing the protocol version */
 #define DP_HARDBARRIER	      1 /* depricated */
 #define DP_RW_SYNC	      2 /* equals REQ_SYNC    */
 #define DP_MAY_SET_IN_SYNC    4
 #define DP_UNPLUG             8 /* not used anymore   */
 #define DP_FUA               16 /* equals REQ_FUA     */
 #define DP_FLUSH             32 /* equals REQ_FLUSH   */
 #define DP_DISCARD           64 /* equals REQ_DISCARD */
 #define DP_SEND_RECEIVE_ACK 128 /* This is a proto B write request */
 #define DP_SEND_WRITE_ACK   256 /* This is a proto C write request */

 struct p_data {
 	u64	    sector;    /* 64 bits sector number */
 	u64	    block_id;  /* to identify the request in protocol B&C */
 	u32	    seq_num;
 	u32	    dp_flags;
 } __packed;

 struct p_trim {
 	struct p_data p_data;
 	u32	    size;	/* == bio->bi_size */
 } __packed;

 /*
  * commands which share a struct:
  *  p_block_ack:
  *   P_RECV_ACK (proto B), P_WRITE_ACK (proto C),
  *   P_SUPERSEDED (proto C, two-primaries conflict detection)
  *  p_block_req:
  *   P_DATA_REQUEST, P_RS_DATA_REQUEST
  */
 struct p_block_ack {
 	u64	    sector;
 	u64	    block_id;
 	u32	    blksize;
 	u32	    seq_num;
 } __packed;

 struct p_block_req {
 	u64 sector;
 	u64 block_id;
 	u32 blksize;
 	u32 pad;	/* to multiple of 8 Byte */
 } __packed;

 /*
  * commands with their own struct for additional fields:
  *   P_CONNECTION_FEATURES
  *   P_BARRIER
  *   P_BARRIER_ACK
  *   P_SYNC_PARAM
  *   ReportParams
  */

 #define FF_TRIM      1

 struct p_connection_features {
 	u32 protocol_min;
 	u32 feature_flags;
 	u32 protocol_max;

 	/* should be more than enough for future enhancements
 	 * for now, feature_flags and the reserved array shall be zero.
 	 */

 	u32 _pad;
 	u64 reserved[7];
 } __packed;

 struct p_barrier {
 	u32 barrier;	/* barrier number _handle_ only */
 	u32 pad;	/* to multiple of 8 Byte */
 } __packed;

 struct p_barrier_ack {
 	u32 barrier;
 	u32 set_size;
 } __packed;

 struct p_rs_param {
 	u32 resync_rate;

 	      /* Since protocol version 88 and higher. */
 	char verify_alg[0];
 } __packed;

 struct p_rs_param_89 {
 	u32 resync_rate;
 	/* protocol version 89: */
 	char verify_alg[SHARED_SECRET_MAX];
 	char csums_alg[SHARED_SECRET_MAX];
 } __packed;

 struct p_rs_param_95 {
 	u32 resync_rate;
 	char verify_alg[SHARED_SECRET_MAX];
 	char csums_alg[SHARED_SECRET_MAX];
 	u32 c_plan_ahead;
 	u32 c_delay_target;
 	u32 c_fill_target;
 	u32 c_max_rate;
 } __packed;

 enum drbd_conn_flags {
 	CF_DISCARD_MY_DATA = 1,
 	CF_DRY_RUN = 2,
 };

 struct p_protocol {
 	u32 protocol;
 	u32 after_sb_0p;
 	u32 after_sb_1p;
 	u32 after_sb_2p;
 	u32 conn_flags;
 	u32 two_primaries;

 	/* Since protocol version 87 and higher. */
 	char integrity_alg[0];

 } __packed;

 struct p_uuids {
 	u64 uuid[UI_EXTENDED_SIZE];
 } __packed;

 struct p_rs_uuid {
 	u64	    uuid;
 } __packed;

 struct p_sizes {
 	u64	    d_size;  /* size of disk */
 	u64	    u_size;  /* user requested size */
 	u64	    c_size;  /* current exported size */
 	u32	    max_bio_size;  /* Maximal size of a BIO */
 	u16	    queue_order_type;  /* not yet implemented in DRBD*/
 	u16	    dds_flags; /* use enum dds_flags here. */
 } __packed;

 struct p_state {
 	u32	    state;
 } __packed;

 struct p_req_state {
 	u32	    mask;
 	u32	    val;
 } __packed;

 struct p_req_state_reply {
 	u32	    retcode;
 } __packed;

 struct p_drbd06_param {
 	u64	  size;
 	u32	  state;
 	u32	  blksize;
 	u32	  protocol;
 	u32	  version;
 	u32	  gen_cnt[5];
 	u32	  bit_map_gen[5];
 } __packed;

 struct p_block_desc {
 	u64 sector;
 	u32 blksize;
 	u32 pad;	/* to multiple of 8 Byte */
 } __packed;

 /* Valid values for the encoding field.
  * Bump proto version when changing this. */
 enum drbd_bitmap_code {
 	/* RLE_VLI_Bytes = 0,
 	 * and other bit variants had been defined during
 	 * algorithm evaluation. */
 	RLE_VLI_Bits = 2,
 };

 struct p_compressed_bm {
 	/* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
 	 * (encoding & 0x80): polarity (set/unset) of first runlength
 	 * ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
 	 * used to pad up to head.length bytes
 	 */
 	u8 encoding;

 	u8 code[0];
 } __packed;

 struct p_delay_probe93 {
 	u32     seq_num; /* sequence number to match the two probe packets */
 	u32     offset;  /* usecs the probe got sent after the reference time point */
 } __packed;

 /*
  * Bitmap packets need to fit within a single page on the sender and receiver,
  * so we are limited to 4 KiB (and not to PAGE_SIZE, which can be bigger).
  */
 #define DRBD_SOCKET_BUFFER_SIZE 4096

 #endif  /* __DRBD_PROTOCOL_H */
	#ifndef __DRBD_PROTOCOL_H
	#define __DRBD_PROTOCOL_H

	enum drbd_packet {
	/* receiver (data socket) */
	P_DATA = 0x00,
	P_DATA_REPLY = 0x01, /* Response to P_DATA_REQUEST */
	P_RS_DATA_REPLY = 0x02, /* Response to P_RS_DATA_REQUEST */
	P_BARRIER = 0x03,
	P_BITMAP = 0x04,
	P_BECOME_SYNC_TARGET = 0x05,
	P_BECOME_SYNC_SOURCE = 0x06,
	P_UNPLUG_REMOTE = 0x07, /* Used at various times to hint the peer */
	P_DATA_REQUEST = 0x08, /* Used to ask for a data block */
	P_RS_DATA_REQUEST = 0x09, /* Used to ask for a data block for resync */
	P_SYNC_PARAM = 0x0a,
	P_PROTOCOL = 0x0b,
	P_UUIDS = 0x0c,
	P_SIZES = 0x0d,
	P_STATE = 0x0e,
	P_SYNC_UUID = 0x0f,
	P_AUTH_CHALLENGE = 0x10,
	P_AUTH_RESPONSE = 0x11,
	P_STATE_CHG_REQ = 0x12,

	/* (meta socket) */
	P_PING = 0x13,
	P_PING_ACK = 0x14,
	P_RECV_ACK = 0x15, /* Used in protocol B */
	P_WRITE_ACK = 0x16, /* Used in protocol C */
	P_RS_WRITE_ACK = 0x17, /* Is a P_WRITE_ACK, additionally call set_in_sync(). */
	P_SUPERSEDED = 0x18, /* Used in proto C, two-primaries conflict detection */
	P_NEG_ACK = 0x19, /* Sent if local disk is unusable */
	P_NEG_DREPLY = 0x1a, /* Local disk is broken... */
	P_NEG_RS_DREPLY = 0x1b, /* Local disk is broken... */
	P_BARRIER_ACK = 0x1c,
	P_STATE_CHG_REPLY = 0x1d,

	/* "new" commands, no longer fitting into the ordering scheme above */

	P_OV_REQUEST = 0x1e, /* data socket */
	P_OV_REPLY = 0x1f,
	P_OV_RESULT = 0x20, /* meta socket */
	P_CSUM_RS_REQUEST = 0x21, /* data socket */
	P_RS_IS_IN_SYNC = 0x22, /* meta socket */
	P_SYNC_PARAM89 = 0x23, /* data socket, protocol version 89 replacement for P_SYNC_PARAM */
	P_COMPRESSED_BITMAP = 0x24, /* compressed or otherwise encoded bitmap transfer */
	/* P_CKPT_FENCE_REQ = 0x25, * currently reserved for protocol D */
	/* P_CKPT_DISABLE_REQ = 0x26, * currently reserved for protocol D */
	P_DELAY_PROBE = 0x27, /* is used on BOTH sockets */
	P_OUT_OF_SYNC = 0x28, /* Mark as out of sync (Outrunning), data socket */
	P_RS_CANCEL = 0x29, /* meta: Used to cancel RS_DATA_REQUEST packet by SyncSource */
	P_CONN_ST_CHG_REQ = 0x2a, /* data sock: Connection wide state request */
	P_CONN_ST_CHG_REPLY = 0x2b, /* meta sock: Connection side state req reply */
	P_RETRY_WRITE = 0x2c, /* Protocol C: retry conflicting write request */
	P_PROTOCOL_UPDATE = 0x2d, /* data sock: is used in established connections */
	/* 0x2e to 0x30 reserved, used in drbd 9 */

	/* REQ_DISCARD. We used "discard" in different contexts before,
	* which is why I chose TRIM here, to disambiguate. */
	P_TRIM = 0x31,

	P_MAY_IGNORE = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
	P_MAX_OPT_CMD = 0x101,

	/* special command ids for handshake */

	P_INITIAL_META = 0xfff1, /* First Packet on the MetaSock */
	P_INITIAL_DATA = 0xfff2, /* First Packet on the Socket */

	P_CONNECTION_FEATURES = 0xfffe /* FIXED for the next century! */
	};

	#ifndef __packed
	#define __packed __attribute__((packed))
	#endif

	/* This is the layout for a packet on the wire.
	* The byteorder is the network byte order.
	* (except block_id and barrier fields.
	* these are pointers to local structs
	* and have no relevance for the partner,
	* which just echoes them as received.)
	*
	* NOTE that the payload starts at a long aligned offset,
	* regardless of 32 or 64 bit arch!
	*/
	struct p_header80 {
	u32 magic;
	u16 command;
	u16 length; /* bytes of data after this header */
	} __packed;

	/* Header for big packets, Used for data packets exceeding 64kB */
	struct p_header95 {
	u16 magic; /* use DRBD_MAGIC_BIG here */
	u16 command;
	u32 length;
	} __packed;

	struct p_header100 {
	u32 magic;
	u16 volume;
	u16 command;
	u32 length;
	u32 pad;
	} __packed;

	/* these defines must not be changed without changing the protocol version */
	#define DP_HARDBARRIER 1 /* depricated */
	#define DP_RW_SYNC 2 /* equals REQ_SYNC */
	#define DP_MAY_SET_IN_SYNC 4
	#define DP_UNPLUG 8 /* not used anymore */
	#define DP_FUA 16 /* equals REQ_FUA */
	#define DP_FLUSH 32 /* equals REQ_FLUSH */
	#define DP_DISCARD 64 /* equals REQ_DISCARD */
	#define DP_SEND_RECEIVE_ACK 128 /* This is a proto B write request */
	#define DP_SEND_WRITE_ACK 256 /* This is a proto C write request */

	struct p_data {
	u64 sector; /* 64 bits sector number */
	u64 block_id; /* to identify the request in protocol B&C */
	u32 seq_num;
	u32 dp_flags;
	} __packed;

	struct p_trim {
	struct p_data p_data;
	u32 size; /* == bio->bi_size */
	} __packed;

	/*
	* commands which share a struct:
	* p_block_ack:
	* P_RECV_ACK (proto B), P_WRITE_ACK (proto C),
	* P_SUPERSEDED (proto C, two-primaries conflict detection)
	* p_block_req:
	* P_DATA_REQUEST, P_RS_DATA_REQUEST
	*/
	struct p_block_ack {
	u64 sector;
	u64 block_id;
	u32 blksize;
	u32 seq_num;
	} __packed;

	struct p_block_req {
	u64 sector;
	u64 block_id;
	u32 blksize;
	u32 pad; /* to multiple of 8 Byte */
	} __packed;

	/*
	* commands with their own struct for additional fields:
	* P_CONNECTION_FEATURES
	* P_BARRIER
	* P_BARRIER_ACK
	* P_SYNC_PARAM
	* ReportParams
	*/

	#define FF_TRIM 1

	struct p_connection_features {
	u32 protocol_min;
	u32 feature_flags;
	u32 protocol_max;

	/* should be more than enough for future enhancements
	* for now, feature_flags and the reserved array shall be zero.
	*/

	u32 _pad;
	u64 reserved[7];
	} __packed;

	struct p_barrier {
	u32 barrier; /* barrier number _handle_ only */
	u32 pad; /* to multiple of 8 Byte */
	} __packed;

	struct p_barrier_ack {
	u32 barrier;
	u32 set_size;
	} __packed;

	struct p_rs_param {
	u32 resync_rate;

	/* Since protocol version 88 and higher. */
	char verify_alg[0];
	} __packed;

	struct p_rs_param_89 {
	u32 resync_rate;
	/* protocol version 89: */
	char verify_alg[SHARED_SECRET_MAX];
	char csums_alg[SHARED_SECRET_MAX];
	} __packed;

	struct p_rs_param_95 {
	u32 resync_rate;
	char verify_alg[SHARED_SECRET_MAX];
	char csums_alg[SHARED_SECRET_MAX];
	u32 c_plan_ahead;
	u32 c_delay_target;
	u32 c_fill_target;
	u32 c_max_rate;
	} __packed;

	enum drbd_conn_flags {
	CF_DISCARD_MY_DATA = 1,
	CF_DRY_RUN = 2,
	};

	struct p_protocol {
	u32 protocol;
	u32 after_sb_0p;
	u32 after_sb_1p;
	u32 after_sb_2p;
	u32 conn_flags;
	u32 two_primaries;

	/* Since protocol version 87 and higher. */
	char integrity_alg[0];

	} __packed;

	struct p_uuids {
	u64 uuid[UI_EXTENDED_SIZE];
	} __packed;

	struct p_rs_uuid {
	u64 uuid;
	} __packed;

	struct p_sizes {
	u64 d_size; /* size of disk */
	u64 u_size; /* user requested size */
	u64 c_size; /* current exported size */
	u32 max_bio_size; /* Maximal size of a BIO */
	u16 queue_order_type; /* not yet implemented in DRBD*/
	u16 dds_flags; /* use enum dds_flags here. */
	} __packed;

	struct p_state {
	u32 state;
	} __packed;

	struct p_req_state {
	u32 mask;
	u32 val;
	} __packed;

	struct p_req_state_reply {
	u32 retcode;
	} __packed;

	struct p_drbd06_param {
	u64 size;
	u32 state;
	u32 blksize;
	u32 protocol;
	u32 version;
	u32 gen_cnt[5];
	u32 bit_map_gen[5];
	} __packed;

	struct p_block_desc {
	u64 sector;
	u32 blksize;
	u32 pad; /* to multiple of 8 Byte */
	} __packed;

	/* Valid values for the encoding field.
	* Bump proto version when changing this. */
	enum drbd_bitmap_code {
	/* RLE_VLI_Bytes = 0,
	* and other bit variants had been defined during
	* algorithm evaluation. */
	RLE_VLI_Bits = 2,
	};

	struct p_compressed_bm {
	/* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
	* (encoding & 0x80): polarity (set/unset) of first runlength
	* ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
	* used to pad up to head.length bytes
	*/
	u8 encoding;

	u8 code[0];
	} __packed;

	struct p_delay_probe93 {
	u32 seq_num; /* sequence number to match the two probe packets */
	u32 offset; /* usecs the probe got sent after the reference time point */
	} __packed;

	/*
	* Bitmap packets need to fit within a single page on the sender and receiver,
	* so we are limited to 4 KiB (and not to PAGE_SIZE, which can be bigger).
	*/
	#define DRBD_SOCKET_BUFFER_SIZE 4096

	#endif /* __DRBD_PROTOCOL_H */