From 25cc084108f03b248a7163e817b7015de9148c39 Mon Sep 17 00:00:00 2001
From: Patrick J Cherry <patrick@bytemark.co.uk>
Date: Thu, 1 Feb 2018 19:25:36 +0000
Subject: [PATCH] First steps towards implementing flags as part of oldstyle
 negotiation

---
 src/common/nbdtypes.c |  2 ++
 src/common/nbdtypes.h | 16 ++++++++++++----
 src/server/client.c   |  4 +++-
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/common/nbdtypes.c b/src/common/nbdtypes.c
index 18bd419..08dc0c9 100644
--- a/src/common/nbdtypes.c
+++ b/src/common/nbdtypes.c
@@ -13,6 +13,7 @@ void nbd_r2h_init( struct nbd_init_raw * from, struct nbd_init * to )
 	memcpy( to->passwd, from->passwd, 8 );
 	to->magic = be64toh( from->magic );
 	to->size = be64toh( from->size );
+	to->flags = be32toh( from->flags );
 }
 
 void nbd_h2r_init( struct nbd_init * from, struct nbd_init_raw * to)
@@ -20,6 +21,7 @@ void nbd_h2r_init( struct nbd_init * from, struct nbd_init_raw * to)
 	memcpy( to->passwd, from->passwd, 8 );
 	to->magic = htobe64( from->magic );
 	to->size = htobe64( from->size );
+	to->flags = htobe32( from->flags );
 }
 
 
diff --git a/src/common/nbdtypes.h b/src/common/nbdtypes.h
index 3e3db22..bc4f413 100644
--- a/src/common/nbdtypes.h
+++ b/src/common/nbdtypes.h
@@ -11,6 +11,14 @@
 #define REQUEST_WRITE 1
 #define REQUEST_DISCONNECT 2
 
+#define NBD_FLAG_HAS_FLAGS         (1 << 0)
+#define NBD_FLAG_READ_ONLY         (1 << 1)
+#define NBD_FLAG_SEND_FLUSH        (1 << 2)
+#define NBD_FLAG_SEND_FUA          (1 << 3)
+#define NBD_FLAG_ROTATIONAL        (1 << 4)
+#define NBD_FLAG_SEND_TRIM         (1 << 5)
+#define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6)
+
 /* The top 2 bytes of the type field are overloaded and can contain flags */
 #define REQUEST_MASK 0x0000ffff
 
@@ -38,7 +46,8 @@ struct nbd_init_raw {
 	char passwd[8];
 	__be64 magic;
 	__be64 size;
-	char reserved[128];
+	__be32 flags;
+	char reserved[124];
 };
 
 struct nbd_request_raw {
@@ -55,13 +64,12 @@ struct nbd_reply_raw {
 	nbd_handle_t handle;         /* handle you got from request  */
 };
 
-
-
 struct nbd_init {
 	char passwd[8];
 	uint64_t magic;
 	uint64_t size;
-	char reserved[128];
+	uint32_t flags;
+	char reserved[124];
 };
 
 struct nbd_request {
diff --git a/src/server/client.c b/src/server/client.c
index 0614a6d..9c23a4d 100644
--- a/src/server/client.c
+++ b/src/server/client.c
@@ -307,7 +307,9 @@ void client_write_init( struct client * client, uint64_t size )
 	memcpy( init.passwd, INIT_PASSWD, sizeof( init.passwd ) );
 	init.magic = INIT_MAGIC;
 	init.size = size;
-	memset( init.reserved, 0, 128 );
+	// TODO actually implement these flags!
+	init.flags = NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA;
+	// memset( init.reserved, 0, 124 );
 
 	nbd_h2r_init( &init, &init_raw );