Updated in https://github.com/libguestfs/nbdkit/commit/XXX Requires tweaks to our handling of nbd magic. --- Will update with a real URL, if we like it. lib/nbd-protocol.h | 35 ++++++++++++++++------------------- generator/states-magic.c | 2 +- 2 files changed, 17 insertions(+), 20 deletions(-) diff --git a/lib/nbd-protocol.h b/lib/nbd-protocol.h index fe4d451..bdd1ef2 100644 --- a/lib/nbd-protocol.h +++ b/lib/nbd-protocol.h @@ -50,7 +50,7 @@ /* Old-style handshake. */ struct nbd_old_handshake { - char nbdmagic[8]; /* "NBDMAGIC" */ + uint64_t nbdmagic; /* NBD_MAGIC */ uint64_t version; /* NBD_OLD_VERSION */ uint64_t exportsize; uint16_t gflags; /* global flags */ @@ -58,30 +58,33 @@ struct nbd_old_handshake { char zeroes[124]; /* must be sent as zero bytes */ } NBD_ATTRIBUTE_PACKED; +#define NBD_MAGIC UINT64_C(0x4e42444d41474943) /* ASCII "NBDMAGIC" */ #define NBD_OLD_VERSION UINT64_C(0x420281861253) /* New-style handshake. */ struct nbd_new_handshake { - char nbdmagic[8]; /* "NBDMAGIC" */ + uint64_t nbdmagic; /* NBD_MAGIC */ uint64_t version; /* NBD_NEW_VERSION */ uint16_t gflags; /* global flags */ } NBD_ATTRIBUTE_PACKED; -#define NBD_NEW_VERSION UINT64_C(0x49484156454F5054) +#define NBD_NEW_VERSION UINT64_C(0x49484156454F5054) /* ASCII "IHAVEOPT" */ /* New-style handshake option (sent by the client to us). */ struct nbd_new_option { - uint64_t version; /* NEW_VERSION */ + uint64_t version; /* NBD_NEW_VERSION */ uint32_t option; /* NBD_OPT_* */ uint32_t optlen; /* option data length */ /* option data follows */ } NBD_ATTRIBUTE_PACKED; -/* Newstyle handshake OPT_EXPORT_NAME reply message. */ +/* Newstyle handshake OPT_EXPORT_NAME reply message. + * Modern clients use NBD_OPT_GO instead of this. + */ struct nbd_export_name_option_reply { - uint64_t exportsize; /* size of export */ - uint16_t eflags; /* per-export flags */ - char zeroes[124]; /* optional zeroes */ + uint64_t exportsize; /* size of export */ + uint16_t eflags; /* per-export flags */ + char zeroes[124]; /* optional zeroes, unless NBD_FLAG_NO_ZEROES */ } NBD_ATTRIBUTE_PACKED; /* Fixed newstyle handshake reply message. */ @@ -95,8 +98,8 @@ struct nbd_fixed_new_option_reply { #define NBD_REP_MAGIC UINT64_C(0x3e889045565a9) /* Global flags. */ -#define NBD_FLAG_FIXED_NEWSTYLE 1 -#define NBD_FLAG_NO_ZEROES 2 +#define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) +#define NBD_FLAG_NO_ZEROES (1 << 1) /* Per-export flags. */ #define NBD_FLAG_HAS_FLAGS (1 << 0) @@ -140,6 +143,9 @@ struct nbd_fixed_new_option_reply { #define NBD_REP_ERR_TOO_BIG NBD_REP_ERR (9) #define NBD_INFO_EXPORT 0 +#define NBD_INFO_NAME 1 +#define NBD_INFO_DESCRIPTION 2 +#define NBD_INFO_BLOCK_SIZE 3 /* NBD_INFO_EXPORT reply (follows fixed_new_option_reply). */ struct nbd_fixed_new_option_reply_info_export { @@ -160,15 +166,6 @@ struct nbd_block_descriptor { uint32_t status_flags; /* block type (hole etc) */ } NBD_ATTRIBUTE_PACKED; -/* New-style handshake server reply when using NBD_OPT_EXPORT_NAME. - * Modern clients use NBD_OPT_GO instead of this. - */ -struct nbd_new_handshake_finish { - uint64_t exportsize; - uint16_t eflags; /* per-export flags */ - char zeroes[124]; /* must be sent as zero bytes */ -} NBD_ATTRIBUTE_PACKED; - /* Request (client -> server). */ struct nbd_request { uint32_t magic; /* NBD_REQUEST_MAGIC. */ diff --git a/generator/states-magic.c b/generator/states-magic.c index de8d235..597620d 100644 --- a/generator/states-magic.c +++ b/generator/states-magic.c @@ -35,7 +35,7 @@ MAGIC.CHECK_MAGIC: uint64_t version; - if (strncmp (h->sbuf.new_handshake.nbdmagic, "NBDMAGIC", 8) != 0) { + if (be64toh (h->sbuf.new_handshake.nbdmagic) != NBD_MAGIC) { SET_NEXT_STATE (%.DEAD); set_error (0, "handshake: server did not send expected NBD magic"); return 0; -- 2.21.0