drivers/block/drbd/drbd_protocol.h

   1 #ifndef __DRBD_PROTOCOL_H
   2 #define __DRBD_PROTOCOL_H
   3
   4 enum 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         P_MAY_IGNORE          = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
  64         P_MAX_OPT_CMD         = 0x101,
  65
  66         /* special command ids for handshake */
  67
  68         P_INITIAL_META        = 0xfff1, /* First Packet on the MetaSock */
  69         P_INITIAL_DATA        = 0xfff2, /* First Packet on the Socket */
  70
  71         P_CONNECTION_FEATURES = 0xfffe  /* FIXED for the next century! */
  72 };
  73
  74 #ifndef __packed
  75 #define __packed __attribute__((packed))
  76 #endif
  77
  78 /* This is the layout for a packet on the wire.
  79  * The byteorder is the network byte order.
  80  *     (except block_id and barrier fields.
  81  *      these are pointers to local structs
  82  *      and have no relevance for the partner,
  83  *      which just echoes them as received.)
  84  *
  85  * NOTE that the payload starts at a long aligned offset,
  86  * regardless of 32 or 64 bit arch!
  87  */
  88 struct p_header80 {
  89         u32       magic;
  90         u16       command;
  91         u16       length;       /* bytes of data after this header */
  92 } __packed;
  93
  94 /* Header for big packets, Used for data packets exceeding 64kB */
  95 struct p_header95 {
  96         u16       magic;        /* use DRBD_MAGIC_BIG here */
  97         u16       command;
  98         u32       length;
  99 } __packed;
 100
 101 struct p_header100 {
 102         u32       magic;
 103         u16       volume;
 104         u16       command;
 105         u32       length;
 106         u32       pad;
 107 } __packed;
 108
 109 /* these defines must not be changed without changing the protocol version */
 110 #define DP_HARDBARRIER        1 /* depricated */
 111 #define DP_RW_SYNC            2 /* equals REQ_SYNC    */
 112 #define DP_MAY_SET_IN_SYNC    4
 113 #define DP_UNPLUG             8 /* not used anymore   */
 114 #define DP_FUA               16 /* equals REQ_FUA     */
 115 #define DP_FLUSH             32 /* equals REQ_PREFLUSH   */
 116 #define DP_DISCARD           64 /* equals REQ_DISCARD */
 117 #define DP_SEND_RECEIVE_ACK 128 /* This is a proto B write request */
 118 #define DP_SEND_WRITE_ACK   256 /* This is a proto C write request */
 119
 120 struct p_data {
 121         u64         sector;    /* 64 bits sector number */
 122         u64         block_id;  /* to identify the request in protocol B&C */
 123         u32         seq_num;
 124         u32         dp_flags;
 125 } __packed;
 126
 127 struct p_trim {
 128         struct p_data p_data;
 129         u32         size;       /* == bio->bi_size */
 130 } __packed;
 131
 132 /*
 133  * commands which share a struct:
 134  *  p_block_ack:
 135  *   P_RECV_ACK (proto B), P_WRITE_ACK (proto C),
 136  *   P_SUPERSEDED (proto C, two-primaries conflict detection)
 137  *  p_block_req:
 138  *   P_DATA_REQUEST, P_RS_DATA_REQUEST
 139  */
 140 struct p_block_ack {
 141         u64         sector;
 142         u64         block_id;
 143         u32         blksize;
 144         u32         seq_num;
 145 } __packed;
 146
 147 struct p_block_req {
 148         u64 sector;
 149         u64 block_id;
 150         u32 blksize;
 151         u32 pad;        /* to multiple of 8 Byte */
 152 } __packed;
 153
 154 /*
 155  * commands with their own struct for additional fields:
 156  *   P_CONNECTION_FEATURES
 157  *   P_BARRIER
 158  *   P_BARRIER_ACK
 159  *   P_SYNC_PARAM
 160  *   ReportParams
 161  */
 162
 163 #define FF_TRIM      1
 164
 165 struct p_connection_features {
 166         u32 protocol_min;
 167         u32 feature_flags;
 168         u32 protocol_max;
 169
 170         /* should be more than enough for future enhancements
 171          * for now, feature_flags and the reserved array shall be zero.
 172          */
 173
 174         u32 _pad;
 175         u64 reserved[7];
 176 } __packed;
 177
 178 struct p_barrier {
 179         u32 barrier;    /* barrier number _handle_ only */
 180         u32 pad;        /* to multiple of 8 Byte */
 181 } __packed;
 182
 183 struct p_barrier_ack {
 184         u32 barrier;
 185         u32 set_size;
 186 } __packed;
 187
 188 struct p_rs_param {
 189         u32 resync_rate;
 190
 191               /* Since protocol version 88 and higher. */
 192         char verify_alg[0];
 193 } __packed;
 194
 195 struct p_rs_param_89 {
 196         u32 resync_rate;
 197         /* protocol version 89: */
 198         char verify_alg[SHARED_SECRET_MAX];
 199         char csums_alg[SHARED_SECRET_MAX];
 200 } __packed;
 201
 202 struct p_rs_param_95 {
 203         u32 resync_rate;
 204         char verify_alg[SHARED_SECRET_MAX];
 205         char csums_alg[SHARED_SECRET_MAX];
 206         u32 c_plan_ahead;
 207         u32 c_delay_target;
 208         u32 c_fill_target;
 209         u32 c_max_rate;
 210 } __packed;
 211
 212 enum drbd_conn_flags {
 213         CF_DISCARD_MY_DATA = 1,
 214         CF_DRY_RUN = 2,
 215 };
 216
 217 struct p_protocol {
 218         u32 protocol;
 219         u32 after_sb_0p;
 220         u32 after_sb_1p;
 221         u32 after_sb_2p;
 222         u32 conn_flags;
 223         u32 two_primaries;
 224
 225         /* Since protocol version 87 and higher. */
 226         char integrity_alg[0];
 227
 228 } __packed;
 229
 230 struct p_uuids {
 231         u64 uuid[UI_EXTENDED_SIZE];
 232 } __packed;
 233
 234 struct p_rs_uuid {
 235         u64         uuid;
 236 } __packed;
 237
 238 struct p_sizes {
 239         u64         d_size;  /* size of disk */
 240         u64         u_size;  /* user requested size */
 241         u64         c_size;  /* current exported size */
 242         u32         max_bio_size;  /* Maximal size of a BIO */
 243         u16         queue_order_type;  /* not yet implemented in DRBD*/
 244         u16         dds_flags; /* use enum dds_flags here. */
 245 } __packed;
 246
 247 struct p_state {
 248         u32         state;
 249 } __packed;
 250
 251 struct p_req_state {
 252         u32         mask;
 253         u32         val;
 254 } __packed;
 255
 256 struct p_req_state_reply {
 257         u32         retcode;
 258 } __packed;
 259
 260 struct p_drbd06_param {
 261         u64       size;
 262         u32       state;
 263         u32       blksize;
 264         u32       protocol;
 265         u32       version;
 266         u32       gen_cnt[5];
 267         u32       bit_map_gen[5];
 268 } __packed;
 269
 270 struct p_block_desc {
 271         u64 sector;
 272         u32 blksize;
 273         u32 pad;        /* to multiple of 8 Byte */
 274 } __packed;
 275
 276 /* Valid values for the encoding field.
 277  * Bump proto version when changing this. */
 278 enum drbd_bitmap_code {
 279         /* RLE_VLI_Bytes = 0,
 280          * and other bit variants had been defined during
 281          * algorithm evaluation. */
 282         RLE_VLI_Bits = 2,
 283 };
 284
 285 struct p_compressed_bm {
 286         /* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
 287          * (encoding & 0x80): polarity (set/unset) of first runlength
 288          * ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
 289          * used to pad up to head.length bytes
 290          */
 291         u8 encoding;
 292
 293         u8 code[0];
 294 } __packed;
 295
 296 struct p_delay_probe93 {
 297         u32     seq_num; /* sequence number to match the two probe packets */
 298         u32     offset;  /* usecs the probe got sent after the reference time point */
 299 } __packed;
 300
 301 /*
 302  * Bitmap packets need to fit within a single page on the sender and receiver,
 303  * so we are limited to 4 KiB (and not to PAGE_SIZE, which can be bigger).
 304  */
 305 #define DRBD_SOCKET_BUFFER_SIZE 4096
 306
 307 #endif  /* __DRBD_PROTOCOL_H */