[PATCH v3 1/2] eal: add functions to generate uuid values

[Stephen Hemminger <stephen@networkplumber.org>]

Useful to be able to generate uuid values for tests or
for interaction with other subsystems as magic cookie.
Naming and overall algorithm come from libuuid which is used
by permission of original author.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/eal/common/eal_common_uuid.c | 56 ++++++++++++++++++++++++++++++++
 lib/eal/include/rte_uuid.h       | 28 +++++++++++++++-
 lib/eal/version.map              |  2 ++
 3 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/lib/eal/common/eal_common_uuid.c b/lib/eal/common/eal_common_uuid.c
index 0a80bfbb38..dfc7c75813 100644
--- a/lib/eal/common/eal_common_uuid.c
+++ b/lib/eal/common/eal_common_uuid.c
@@ -3,12 +3,18 @@
  */
 
 #include <stdio.h>
+#include <stdbool.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <ctype.h>
+#include <time.h>
 
+#include <rte_stdatomic.h>
+#include <rte_random.h>
+#include <rte_time.h>
 #include <rte_uuid.h>
+#include <rte_os_shim.h>
 
 /* UUID packed form */
 struct uuid {
@@ -165,3 +171,53 @@ void rte_uuid_unparse(const rte_uuid_t uu, char *out, size_t len)
 		uuid.node[0], uuid.node[1], uuid.node[2],
 		uuid.node[3], uuid.node[4], uuid.node[5]);
 }
+
+void rte_uuid_generate_random(rte_uuid_t out)
+{
+	union {
+		uint64_t words[2];
+		rte_uuid_t uuid;
+	} buf;
+	struct uuid uu;
+
+	/* UUID is 128 bit */
+	buf.words[0] = rte_rand();
+	buf.words[1] = rte_rand();
+
+	/* Mark these random bytes a version 4 random uuid */
+	uuid_unpack(buf.uuid, &uu);
+	uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
+	uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
+	uuid_pack(&uu, out);
+}
+
+void rte_uuid_generate_time(rte_uuid_t out)
+{
+	struct uuid uu;
+	struct timespec ts;
+	uint64_t ns, rnd;
+	static RTE_ATOMIC(uint16_t) sequence;
+
+	/* The time value for UUID is 100ns since 15 October 1582 */
+	clock_gettime(CLOCK_REALTIME, &ts);
+
+	ns = ts.tv_nsec / 100;
+	ns += (uint64_t) ts.tv_sec * (NSEC_PER_SEC / 100);
+	ns += (((uint64_t) 0x01B21DD2) << 32) + 0x13814000;
+
+	uu.time_low = (uint32_t) ns;
+	uu.time_mid = (uint16_t) (ns >> 32);
+	uu.time_hi_and_version = (uint16_t) (ns >> 48);
+	uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
+	uu.clock_seq = rte_atomic_fetch_add_explicit(&sequence, 1, rte_memory_order_relaxed);
+
+	rnd = rte_rand();
+	memcpy(uu.node, &rnd, 6);
+	/*
+	 * Follow the convention so that random node part will not
+	 * not match a valid MAC address,
+	 */
+	uu.node[0] |= 0x1;
+
+	uuid_pack(&uu, out);
+}
diff --git a/lib/eal/include/rte_uuid.h b/lib/eal/include/rte_uuid.h
index cfefd4308a..928a8312d9 100644
--- a/lib/eal/include/rte_uuid.h
+++ b/lib/eal/include/rte_uuid.h
@@ -18,6 +18,8 @@ extern "C" {
 #include <stddef.h>
 #include <string.h>
 
+#include <rte_compat.h>
+
 /**
  * Struct describing a Universal Unique Identifier
  */
@@ -94,12 +96,36 @@ int	rte_uuid_parse(const char *in, rte_uuid_t uu);
  * @param uu
  *    UUID to format
  * @param out
- *    Resulting string buffer
+ *    Resulting string bufferm
  * @param len
  *    Sizeof the available string buffer
  */
 void	rte_uuid_unparse(const rte_uuid_t uu, char *out, size_t len);
 
+/**
+ * Generate a random uuid
+ *
+ * Uses high quality pseudo-random generator rte_rand() to generate a universal
+ * unique identifier.
+ *
+ * @param uu
+ *   Resulting UUID
+ */
+__rte_experimental
+void   rte_uuid_generate_random(rte_uuid_t uu);
+
+/**
+ * Generate a uuid based on time stamp.
+ *
+ * Uses the current time and a random Ethernet MAC address to generate a
+ * universal unique identifier.
+ *
+ * @param uu
+ *   Resulting UUID
+ */
+__rte_experimental
+void   rte_uuid_generate_time(rte_uuid_t uu);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/eal/version.map b/lib/eal/version.map
index 3df50c3fbb..5a8aa67244 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -396,6 +396,8 @@ EXPERIMENTAL {
 
 	# added in 24.03
 	rte_vfio_get_device_info; # WINDOWS_NO_EXPORT
+	rte_uuid_generate_random;
+	rte_uuid_generate_time;
 };
 
 INTERNAL {
-- 
2.43.0