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Subject[PATCH 05/16] uuid: add the v1 layout to uuid_t
Date
Turn the content of uuid_t into a union and add the fields for the v1
interpretation to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/uapi/linux/uuid.h | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/uuid.h b/include/uapi/linux/uuid.h
index 1a2914d8b225..1039d2f3e114 100644
--- a/include/uapi/linux/uuid.h
+++ b/include/uapi/linux/uuid.h
@@ -25,7 +25,34 @@ typedef struct {
} guid_t;

typedef struct {
- __u8 b[16];
+ union {
+ __u8 b[16];
+
+ /*
+ * V1 (time-based) UUID definition [RFC 4122]:
+ * - the timestamp is a 60-bit value, split 32/16/12, and goes
+ * in 100ns increments since midnight 15th October 1582
+ * - add UUID_TO_UNIX_TIME to convert unix time in 100ns
+ * units to UUID time
+ * - the clock sequence is a 14-bit counter to avoid duplicate
+ * times
+ */
+ struct {
+ __be32 time_low;
+ __be16 time_mid;
+ __be16 time_hi_and_version;
+#define UUID_TO_UNIX_TIME 0x01b21dd213814000ULL
+#define UUID_TIMEHI_MASK 0x0fff
+#define UUID_VERSION_TIME 0x1000 /* time-based UUID */
+#define UUID_VERSION_NAME 0x3000 /* name-based UUID */
+#define UUID_VERSION_RANDOM 0x4000 /* (pseudo-)random generated UUID */
+ u8 clock_seq_hi_and_reserved;
+#define UUID_CLOCKHI_MASK 0x3f
+#define UUID_VARIANT_STD 0x80
+ u8 clock_seq_low;
+ u8 node[6];
+ } v1;
+ };
} uuid_t;

#define GUID(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7) \
--
2.11.0
\
 
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