9:52 a.m.
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