[PATCH v4 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       | 26 +++++++++++++++
 lib/eal/version.map              |  4 +++
 3 files changed, 86 insertions(+)

diff --git a/lib/eal/common/eal_common_uuid.c b/lib/eal/common/eal_common_uuid.c
index 0a80bfbb38..a185ccb881 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 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..5fe7d32d39 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
  */
@@ -100,6 +102,30 @@ int	rte_uuid_parse(const char *in, rte_uuid_t uu);
  */
 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..aca0d97c63 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -396,6 +396,10 @@ EXPERIMENTAL {
 
 	# added in 24.03
 	rte_vfio_get_device_info; # WINDOWS_NO_EXPORT
+
+	# added in 24.07
+	rte_uuid_generate_random;
+	rte_uuid_generate_time;
 };
 
 INTERNAL {
-- 
2.43.0