Re: [Libguestfs] [libnbd PATCH v4 3/6] protocol: Add definitions for extended headers

Add the magic numbers and new structs necessary to implement the NBD protocol extension of extended headers providing 64-bit lengths. This corresponds to upstream nbd commits 36abf47d and a9384e2f on the extension-ext-header branch[1] (commit e6f3b94a for NBD_FLAG_BLOCK_STATUS_PAYLOAD is saved for a later patch). [1] https://github.com/NetworkBlockDevice/nbd/blob/extension-ext-header/doc/p... Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; Reviewed-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- v4: tweak comment on block_status_64.count [Laszlo], rebase to earlier struct renames (for example, nbd_block_descriptor_64 instead of nbd_structured_reply_block_status_hdr). Seemed obvious enough that I felt okay keeping Laszlo's R-b. --- lib/nbd-protocol.h | 55 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/lib/nbd-protocol.h b/lib/nbd-protocol.h index 58583d1d..b5a28ae4 100644 --- a/lib/nbd-protocol.h +++ b/lib/nbd-protocol.h @@ -124,6 +124,7 @@ struct nbd_fixed_new_option_reply { #define NBD_OPT_STRUCTURED_REPLY 8 #define NBD_OPT_LIST_META_CONTEXT 9 #define NBD_OPT_SET_META_CONTEXT 10 +#define NBD_OPT_EXTENDED_HEADERS 11 #define NBD_REP_ERR(val) (0x80000000 | (val)) #define NBD_REP_IS_ERR(val) (!!((val) & 0x80000000)) @@ -141,6 +142,7 @@ struct nbd_fixed_new_option_reply { #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR (7) #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR (8) #define NBD_REP_ERR_TOO_BIG NBD_REP_ERR (9) +#define NBD_REP_ERR_EXT_HEADER_REQD NBD_REP_ERR (10) #define NBD_INFO_EXPORT 0 #define NBD_INFO_NAME 1 @@ -182,16 +184,26 @@ struct nbd_fixed_new_option_reply_meta_context { /* followed by a string */ } NBD_ATTRIBUTE_PACKED; -/* Request (client -> server). */ +/* Compact request (client -> server). */ struct nbd_request { uint32_t magic; /* NBD_REQUEST_MAGIC. */ - uint16_t flags; /* Request flags. */ - uint16_t type; /* Request type. */ + uint16_t flags; /* Request flags: NBD_CMD_FLAG_*. */ + uint16_t type; /* Request type: NBD_CMD_*. */ uint64_t cookie; /* Opaque handle. */ uint64_t offset; /* Request offset. */ uint32_t count; /* Request length. */ } NBD_ATTRIBUTE_PACKED; +/* Extended request (client -> server). */ +struct nbd_request_ext { + uint32_t magic; /* NBD_EXTENDED_REQUEST_MAGIC. */ + uint16_t flags; /* Request flags: NBD_CMD_FLAG_*. */ + uint16_t type; /* Request type: NBD_CMD_*. */ + uint64_t cookie; /* Opaque handle. */ + uint64_t offset; /* Request offset. */ + uint64_t count; /* Request effect or payload length. */ +} NBD_ATTRIBUTE_PACKED; + /* Simple reply (server -> client). */ struct nbd_simple_reply { uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC. */ @@ -208,6 +220,16 @@ struct nbd_structured_reply { uint32_t length; /* Length of following nbd_chunk_* payload. */ } NBD_ATTRIBUTE_PACKED; +/* Extended reply (server -> client). */ +struct nbd_extended_reply { + uint32_t magic; /* NBD_EXTENDED_REPLY_MAGIC. */ + uint16_t flags; /* NBD_REPLY_FLAG_* */ + uint16_t type; /* NBD_REPLY_TYPE_* */ + uint64_t cookie; /* Opaque handle. */ + uint64_t offset; /* Client's offset. */ + uint64_t length; /* Length of following nbd_chunk_* payload. */ +} NBD_ATTRIBUTE_PACKED; + struct nbd_chunk_offset_data { uint64_t offset; /* offset */ /* Followed by data. */ @@ -228,6 +250,17 @@ struct nbd_block_descriptor_32 { uint32_t status_flags; /* block type (hole etc) */ } NBD_ATTRIBUTE_PACKED; +struct nbd_chunk_block_status_64 { + uint32_t context_id; /* metadata context ID */ + uint32_t count; /* non-zero descriptor count */ + /* followed by nbd_block_descriptor_64[count] extents */ +} NBD_ATTRIBUTE_PACKED; + +struct nbd_block_descriptor_64 { + uint64_t length; /* length of block */ + uint64_t status_flags; /* block type (hole etc) */ +} NBD_ATTRIBUTE_PACKED; + struct nbd_chunk_error { uint32_t error; /* NBD_E* error number */ uint16_t len; /* Length of human readable error. */ @@ -235,8 +268,10 @@ struct nbd_chunk_error { } NBD_ATTRIBUTE_PACKED; #define NBD_REQUEST_MAGIC 0x25609513 +#define NBD_EXTENDED_REQUEST_MAGIC 0x21e41c71 #define NBD_SIMPLE_REPLY_MAGIC 0x67446698 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef +#define NBD_EXTENDED_REPLY_MAGIC 0x6e8a278c /* Structured reply flags. */ #define NBD_REPLY_FLAG_DONE (1U << 0) @@ -245,12 +280,13 @@ struct nbd_chunk_error { #define NBD_REPLY_TYPE_IS_ERR(val) (!!((val) & (1U<<15))) /* Structured reply types. */ -#define NBD_REPLY_TYPE_NONE 0 -#define NBD_REPLY_TYPE_OFFSET_DATA 1 -#define NBD_REPLY_TYPE_OFFSET_HOLE 2 -#define NBD_REPLY_TYPE_BLOCK_STATUS 5 -#define NBD_REPLY_TYPE_ERROR NBD_REPLY_TYPE_ERR (1) -#define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_TYPE_ERR (2) +#define NBD_REPLY_TYPE_NONE 0 +#define NBD_REPLY_TYPE_OFFSET_DATA 1 +#define NBD_REPLY_TYPE_OFFSET_HOLE 2 +#define NBD_REPLY_TYPE_BLOCK_STATUS 5 +#define NBD_REPLY_TYPE_BLOCK_STATUS_EXT 6 +#define NBD_REPLY_TYPE_ERROR NBD_REPLY_TYPE_ERR (1) +#define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_TYPE_ERR (2) /* NBD commands. */ #define NBD_CMD_READ 0 @@ -267,6 +303,7 @@ struct nbd_chunk_error { #define NBD_CMD_FLAG_DF (1U << 2) #define NBD_CMD_FLAG_REQ_ONE (1U << 3) #define NBD_CMD_FLAG_FAST_ZERO (1U << 4) +#define NBD_CMD_FLAG_PAYLOAD_LEN (1U << 5) /* NBD error codes. */ #define NBD_SUCCESS 0