aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/block/drbd/drbd_protocol.h
blob: 3c04ec0ea3330cb56302fd3367f04e850ea2055f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
#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,

	/* asender (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 */

	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;

/*
 * 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
 */

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 */