1 /* SPDX-License-Identifier: GPL-2.0 */ 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 27 /* (meta socket) */ 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 */ 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, 63 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 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 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; 118 119 /* 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 */ 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 */ 128 #define DP_FLUSH 32 /* equals REQ_PREFLUSH */ 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 */ 132 #define DP_WSAME 512 /* equiv. REQ_WRITE_SAME */ 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; 140 141 struct p_trim { 142 struct p_data p_data; 143 u32 size; /* == bio->bi_size */ 144 } __packed; 145 146 struct p_wsame { 147 struct p_data p_data; 148 u32 size; /* == bio->bi_size */ 149 } __packed; 150 151 /* 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 */ 181 182 /* 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 4 199 200 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; 272 273 /* 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; 306 307 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. */ 314 315 /* optional queue_limits if (agreed_features & DRBD_FF_WSAME) */ 316 struct o_qlim qlim[0]; 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 */ 380
