[linux-block.git] / drivers / block / drbd / drbd_protocol.h

/* SPDX-License-Identifier: GPL-2.0 */
#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,

	/* Only use these two if both support FF_THIN_RESYNC */
	P_RS_THIN_REQ         = 0x32, /* Request a block for resync or reply P_RS_DEALLOCATED */
	P_RS_DEALLOCATED      = 0x33, /* Contains only zeros on sync source node */

	/* REQ_WRITE_SAME.
	 * On a receiving side without REQ_WRITE_SAME,
	 * we may fall back to an opencoded loop instead. */
	P_WSAME               = 0x34,

	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.
 * New defines may only be introduced together with protocol version bump or
 * new protocol feature flags.
 */
#define DP_HARDBARRIER	      1 /* no longer used */
#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_PREFLUSH   */
#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 */
#define DP_WSAME            512 /* equiv. REQ_WRITE_SAME */

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;

struct p_wsame {
	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
 */

/* supports TRIM/DISCARD on the "wire" protocol */
#define DRBD_FF_TRIM 1

/* Detect all-zeros during resync, and rather TRIM/UNMAP/DISCARD those blocks
 * instead of fully allocate a supposedly thin volume on initial resync */
#define DRBD_FF_THIN_RESYNC 2

/* supports REQ_WRITE_SAME on the "wire" protocol.
 * Note: this flag is overloaded,
 * its presence also
 *   - indicates support for 128 MiB "batch bios",
 *     max discard size of 128 MiB
 *     instead of 4M before that.
 *   - indicates that we exchange additional settings in p_sizes
 *     drbd_send_sizes()/receive_sizes()
 */
#define DRBD_FF_WSAME 4

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;

/* optional queue_limits if (agreed_features & DRBD_FF_WSAME)
 * see also struct queue_limits, as of late 2015 */
struct o_qlim {
	/* we don't need it yet, but we may as well communicate it now */
	u32 physical_block_size;

	/* so the original in struct queue_limits is unsigned short,
	 * but I'd have to put in padding anyways. */
	u32 logical_block_size;

	/* One incoming bio becomes one DRBD request,
	 * which may be translated to several bio on the receiving side.
	 * We don't need to communicate chunk/boundary/segment ... limits.
	 */

	/* various IO hints may be useful with "diskless client" setups */
	u32 alignment_offset;
	u32 io_min;
	u32 io_opt;

	/* We may need to communicate integrity stuff at some point,
	 * but let's not get ahead of ourselves. */

	/* Backend discard capabilities.
	 * Receiving side uses "blkdev_issue_discard()", no need to communicate
	 * more specifics.  If the backend cannot do discards, the DRBD peer
	 * may fall back to blkdev_issue_zeroout().
	 */
	u8 discard_enabled;
	u8 discard_zeroes_data;
	u8 write_same_capable;
	u8 _pad;
} __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. */

	/* optional queue_limits if (agreed_features & DRBD_FF_WSAME) */
	struct o_qlim qlim[0];
} __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 */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
a3603a6e AG	2	#ifndef __DRBD_PROTOCOL_H
	3	#define __DRBD_PROTOCOL_H
	4
	5	enum drbd_packet {
	6	/* receiver (data socket) */
	7	P_DATA = 0x00,
	8	P_DATA_REPLY = 0x01, /* Response to P_DATA_REQUEST */
	9	P_RS_DATA_REPLY = 0x02, /* Response to P_RS_DATA_REQUEST */
	10	P_BARRIER = 0x03,
	11	P_BITMAP = 0x04,
	12	P_BECOME_SYNC_TARGET = 0x05,
	13	P_BECOME_SYNC_SOURCE = 0x06,
	14	P_UNPLUG_REMOTE = 0x07, /* Used at various times to hint the peer */
	15	P_DATA_REQUEST = 0x08, /* Used to ask for a data block */
	16	P_RS_DATA_REQUEST = 0x09, /* Used to ask for a data block for resync */
	17	P_SYNC_PARAM = 0x0a,
	18	P_PROTOCOL = 0x0b,
	19	P_UUIDS = 0x0c,
	20	P_SIZES = 0x0d,
	21	P_STATE = 0x0e,
	22	P_SYNC_UUID = 0x0f,
	23	P_AUTH_CHALLENGE = 0x10,
	24	P_AUTH_RESPONSE = 0x11,
	25	P_STATE_CHG_REQ = 0x12,
	26
668700b4	27	/* (meta socket) */
a3603a6e AG	28	P_PING = 0x13,
	29	P_PING_ACK = 0x14,
	30	P_RECV_ACK = 0x15, /* Used in protocol B */
	31	P_WRITE_ACK = 0x16, /* Used in protocol C */
	32	P_RS_WRITE_ACK = 0x17, /* Is a P_WRITE_ACK, additionally call set_in_sync(). */
	33	P_SUPERSEDED = 0x18, /* Used in proto C, two-primaries conflict detection */
	34	P_NEG_ACK = 0x19, /* Sent if local disk is unusable */
	35	P_NEG_DREPLY = 0x1a, /* Local disk is broken... */
	36	P_NEG_RS_DREPLY = 0x1b, /* Local disk is broken... */
	37	P_BARRIER_ACK = 0x1c,
	38	P_STATE_CHG_REPLY = 0x1d,
	39
	40	/* "new" commands, no longer fitting into the ordering scheme above */
	41
	42	P_OV_REQUEST = 0x1e, /* data socket */
	43	P_OV_REPLY = 0x1f,
	44	P_OV_RESULT = 0x20, /* meta socket */
	45	P_CSUM_RS_REQUEST = 0x21, /* data socket */
	46	P_RS_IS_IN_SYNC = 0x22, /* meta socket */
	47	P_SYNC_PARAM89 = 0x23, /* data socket, protocol version 89 replacement for P_SYNC_PARAM */
	48	P_COMPRESSED_BITMAP = 0x24, /* compressed or otherwise encoded bitmap transfer */
	49	/* P_CKPT_FENCE_REQ = 0x25, * currently reserved for protocol D */
	50	/* P_CKPT_DISABLE_REQ = 0x26, * currently reserved for protocol D */
	51	P_DELAY_PROBE = 0x27, /* is used on BOTH sockets */
	52	P_OUT_OF_SYNC = 0x28, /* Mark as out of sync (Outrunning), data socket */
	53	P_RS_CANCEL = 0x29, /* meta: Used to cancel RS_DATA_REQUEST packet by SyncSource */
	54	P_CONN_ST_CHG_REQ = 0x2a, /* data sock: Connection wide state request */
	55	P_CONN_ST_CHG_REPLY = 0x2b, /* meta sock: Connection side state req reply */
	56	P_RETRY_WRITE = 0x2c, /* Protocol C: retry conflicting write request */
	57	P_PROTOCOL_UPDATE = 0x2d, /* data sock: is used in established connections */
a0fb3c47 LE	58	/* 0x2e to 0x30 reserved, used in drbd 9 */
	59
	60	/* REQ_DISCARD. We used "discard" in different contexts before,
	61	* which is why I chose TRIM here, to disambiguate. */
	62	P_TRIM = 0x31,
a3603a6e	63
700ca8c0 PR	64	/* Only use these two if both support FF_THIN_RESYNC */
	65	P_RS_THIN_REQ = 0x32, /* Request a block for resync or reply P_RS_DEALLOCATED */
	66	P_RS_DEALLOCATED = 0x33, /* Contains only zeros on sync source node */
	67
9104d31a LE	68	/* REQ_WRITE_SAME.
	69	* On a receiving side without REQ_WRITE_SAME,
	70	* we may fall back to an opencoded loop instead. */
	71	P_WSAME = 0x34,
	72
a3603a6e AG	73	P_MAY_IGNORE = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
	74	P_MAX_OPT_CMD = 0x101,
	75
	76	/* special command ids for handshake */
	77
	78	P_INITIAL_META = 0xfff1, /* First Packet on the MetaSock */
	79	P_INITIAL_DATA = 0xfff2, /* First Packet on the Socket */
	80
	81	P_CONNECTION_FEATURES = 0xfffe /* FIXED for the next century! */
	82	};
	83
	84	#ifndef __packed
	85	#define __packed __attribute__((packed))
	86	#endif
	87
	88	/* This is the layout for a packet on the wire.
	89	* The byteorder is the network byte order.
	90	* (except block_id and barrier fields.
	91	* these are pointers to local structs
	92	* and have no relevance for the partner,
	93	* which just echoes them as received.)
	94	*
	95	* NOTE that the payload starts at a long aligned offset,
	96	* regardless of 32 or 64 bit arch!
	97	*/
	98	struct p_header80 {
	99	u32 magic;
	100	u16 command;
	101	u16 length; /* bytes of data after this header */
	102	} __packed;
	103
	104	/* Header for big packets, Used for data packets exceeding 64kB */
	105	struct p_header95 {
	106	u16 magic; /* use DRBD_MAGIC_BIG here */
	107	u16 command;
	108	u32 length;
	109	} __packed;
	110
	111	struct p_header100 {
	112	u32 magic;
	113	u16 volume;
	114	u16 command;
	115	u32 length;
	116	u32 pad;
	117	} __packed;
	118
9104d31a LE	119	/* These defines must not be changed without changing the protocol version.
	120	* New defines may only be introduced together with protocol version bump or
	121	* new protocol feature flags.
	122	*/
	123	#define DP_HARDBARRIER 1 /* no longer used */
a3603a6e AG	124	#define DP_RW_SYNC 2 /* equals REQ_SYNC */
	125	#define DP_MAY_SET_IN_SYNC 4
	126	#define DP_UNPLUG 8 /* not used anymore */
	127	#define DP_FUA 16 /* equals REQ_FUA */
28a8f0d3	128	#define DP_FLUSH 32 /* equals REQ_PREFLUSH */
a3603a6e AG	129	#define DP_DISCARD 64 /* equals REQ_DISCARD */
	130	#define DP_SEND_RECEIVE_ACK 128 /* This is a proto B write request */
	131	#define DP_SEND_WRITE_ACK 256 /* This is a proto C write request */
9104d31a	132	#define DP_WSAME 512 /* equiv. REQ_WRITE_SAME */
a3603a6e AG	133
	134	struct p_data {
	135	u64 sector; /* 64 bits sector number */
	136	u64 block_id; /* to identify the request in protocol B&C */
	137	u32 seq_num;
	138	u32 dp_flags;
	139	} __packed;
	140
a0fb3c47 LE	141	struct p_trim {
	142	struct p_data p_data;
	143	u32 size; /* == bio->bi_size */
	144	} __packed;
	145
9104d31a LE	146	struct p_wsame {
	147	struct p_data p_data;
	148	u32 size; /* == bio->bi_size */
	149	} __packed;
	150
a3603a6e AG	151	/*
	152	* commands which share a struct:
	153	* p_block_ack:
	154	* P_RECV_ACK (proto B), P_WRITE_ACK (proto C),
	155	* P_SUPERSEDED (proto C, two-primaries conflict detection)
	156	* p_block_req:
	157	* P_DATA_REQUEST, P_RS_DATA_REQUEST
	158	*/
	159	struct p_block_ack {
	160	u64 sector;
	161	u64 block_id;
	162	u32 blksize;
	163	u32 seq_num;
	164	} __packed;
	165
	166	struct p_block_req {
	167	u64 sector;
	168	u64 block_id;
	169	u32 blksize;
	170	u32 pad; /* to multiple of 8 Byte */
	171	} __packed;
	172
	173	/*
	174	* commands with their own struct for additional fields:
	175	* P_CONNECTION_FEATURES
	176	* P_BARRIER
	177	* P_BARRIER_ACK
	178	* P_SYNC_PARAM
	179	* ReportParams
	180	*/
	181
9104d31a LE	182	/* supports TRIM/DISCARD on the "wire" protocol */
	183	#define DRBD_FF_TRIM 1
	184
	185	/* Detect all-zeros during resync, and rather TRIM/UNMAP/DISCARD those blocks
	186	* instead of fully allocate a supposedly thin volume on initial resync */
	187	#define DRBD_FF_THIN_RESYNC 2
	188
	189	/* supports REQ_WRITE_SAME on the "wire" protocol.
	190	* Note: this flag is overloaded,
	191	* its presence also
	192	* - indicates support for 128 MiB "batch bios",
	193	* max discard size of 128 MiB
	194	* instead of 4M before that.
	195	* - indicates that we exchange additional settings in p_sizes
	196	* drbd_send_sizes()/receive_sizes()
	197	*/
	198	#define DRBD_FF_WSAME 4
20c68fde	199
a3603a6e AG	200	struct p_connection_features {
	201	u32 protocol_min;
	202	u32 feature_flags;
	203	u32 protocol_max;
	204
	205	/* should be more than enough for future enhancements
	206	* for now, feature_flags and the reserved array shall be zero.
	207	*/
	208
	209	u32 _pad;
	210	u64 reserved[7];
	211	} __packed;
	212
	213	struct p_barrier {
	214	u32 barrier; /* barrier number _handle_ only */
	215	u32 pad; /* to multiple of 8 Byte */
	216	} __packed;
	217
	218	struct p_barrier_ack {
	219	u32 barrier;
	220	u32 set_size;
	221	} __packed;
	222
	223	struct p_rs_param {
	224	u32 resync_rate;
	225
	226	/* Since protocol version 88 and higher. */
	227	char verify_alg[0];
	228	} __packed;
	229
	230	struct p_rs_param_89 {
	231	u32 resync_rate;
	232	/* protocol version 89: */
	233	char verify_alg[SHARED_SECRET_MAX];
	234	char csums_alg[SHARED_SECRET_MAX];
	235	} __packed;
	236
	237	struct p_rs_param_95 {
	238	u32 resync_rate;
	239	char verify_alg[SHARED_SECRET_MAX];
	240	char csums_alg[SHARED_SECRET_MAX];
	241	u32 c_plan_ahead;
	242	u32 c_delay_target;
	243	u32 c_fill_target;
	244	u32 c_max_rate;
	245	} __packed;
	246
	247	enum drbd_conn_flags {
	248	CF_DISCARD_MY_DATA = 1,
	249	CF_DRY_RUN = 2,
	250	};
	251
	252	struct p_protocol {
	253	u32 protocol;
	254	u32 after_sb_0p;
	255	u32 after_sb_1p;
	256	u32 after_sb_2p;
	257	u32 conn_flags;
	258	u32 two_primaries;
	259
	260	/* Since protocol version 87 and higher. */
	261	char integrity_alg[0];
	262
	263	} __packed;
264
265	struct p_uuids {
266	u64 uuid[UI_EXTENDED_SIZE];
267	} __packed;
268
269	struct p_rs_uuid {
270	u64 uuid;
271	} __packed;
272
9104d31a LE	273	/* optional queue_limits if (agreed_features & DRBD_FF_WSAME)
	274	* see also struct queue_limits, as of late 2015 */
	275	struct o_qlim {
	276	/* we don't need it yet, but we may as well communicate it now */
	277	u32 physical_block_size;
	278
	279	/* so the original in struct queue_limits is unsigned short,
	280	* but I'd have to put in padding anyways. */
	281	u32 logical_block_size;
	282
	283	/* One incoming bio becomes one DRBD request,
	284	* which may be translated to several bio on the receiving side.
	285	* We don't need to communicate chunk/boundary/segment ... limits.
	286	*/
	287
	288	/* various IO hints may be useful with "diskless client" setups */
	289	u32 alignment_offset;
	290	u32 io_min;
	291	u32 io_opt;
	292
	293	/* We may need to communicate integrity stuff at some point,
	294	* but let's not get ahead of ourselves. */
	295
	296	/* Backend discard capabilities.
	297	* Receiving side uses "blkdev_issue_discard()", no need to communicate
	298	* more specifics. If the backend cannot do discards, the DRBD peer
	299	* may fall back to blkdev_issue_zeroout().
	300	*/
	301	u8 discard_enabled;
	302	u8 discard_zeroes_data;
	303	u8 write_same_capable;
	304	u8 _pad;
	305	} __packed;
	306
a3603a6e AG	307	struct p_sizes {
	308	u64 d_size; /* size of disk */
	309	u64 u_size; /* user requested size */
	310	u64 c_size; /* current exported size */
	311	u32 max_bio_size; /* Maximal size of a BIO */
	312	u16 queue_order_type; /* not yet implemented in DRBD*/
	313	u16 dds_flags; /* use enum dds_flags here. */
9104d31a LE	314
	315	/* optional queue_limits if (agreed_features & DRBD_FF_WSAME) */
	316	struct o_qlim qlim[0];
a3603a6e AG	317	} __packed;
	318
	319	struct p_state {
	320	u32 state;
	321	} __packed;
	322
	323	struct p_req_state {
	324	u32 mask;
	325	u32 val;
	326	} __packed;
	327
	328	struct p_req_state_reply {
	329	u32 retcode;
	330	} __packed;
	331
	332	struct p_drbd06_param {
	333	u64 size;
	334	u32 state;
	335	u32 blksize;
	336	u32 protocol;
	337	u32 version;
	338	u32 gen_cnt[5];
	339	u32 bit_map_gen[5];
	340	} __packed;
	341
	342	struct p_block_desc {
	343	u64 sector;
	344	u32 blksize;
	345	u32 pad; /* to multiple of 8 Byte */
	346	} __packed;
	347
	348	/* Valid values for the encoding field.
	349	* Bump proto version when changing this. */
	350	enum drbd_bitmap_code {
	351	/* RLE_VLI_Bytes = 0,
	352	* and other bit variants had been defined during
	353	* algorithm evaluation. */
	354	RLE_VLI_Bits = 2,
	355	};
	356
	357	struct p_compressed_bm {
	358	/* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
	359	* (encoding & 0x80): polarity (set/unset) of first runlength
	360	* ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
	361	* used to pad up to head.length bytes
	362	*/
	363	u8 encoding;
	364
	365	u8 code[0];
	366	} __packed;
	367
	368	struct p_delay_probe93 {
	369	u32 seq_num; /* sequence number to match the two probe packets */
	370	u32 offset; /* usecs the probe got sent after the reference time point */
	371	} __packed;
	372
	373	/*
	374	* Bitmap packets need to fit within a single page on the sender and receiver,
	375	* so we are limited to 4 KiB (and not to PAGE_SIZE, which can be bigger).
	376	*/
	377	#define DRBD_SOCKET_BUFFER_SIZE 4096
	378
	379	#endif /* __DRBD_PROTOCOL_H */