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