[U-Boot] [PATCH v4 3/6] lib: uuid: add functions to generate UUID version 4
Przemyslaw Marczak
p.marczak at samsung.com
Wed Mar 19 18:58:28 CET 2014
This patch adds support to generate UUID (Universally Unique Identifier)
in version 4 based on RFC4122, which is randomly.
Source: https://www.ietf.org/rfc/rfc4122.txt
Changes:
- add new config: CONFIG_RANDOM_UUID: compile uuid.c and rand.c
lib/uuid.c:
- add gen_rand_uuid() - this function writes 16 bytes len binary representati
UUID v4 to the memory at given address.
- add gen_rand_uuid_str() - this function writes 37 bytes len hexadecimal
ASCII string representation of UUID v4 to the memory at given address.
Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
Cc: Stephen Warren <swarren at nvidia.com>
Cc: Lukasz Majewski <l.majewski at samsung.com>
Cc: trini at ti.com
---
Changes v2:
- put uuid generation changes in a separate commit
- get_uuid_str() - change name to gen_rand_uuid_str()
- add new function: gen_rand_uuid()
- remove unnecessary '\0' at the end of uuid string
- drop unnecessary error checking
- functions now takes pointers to allocated memory instead of alloc it itself
- add new config option: CONFIG_RANDOM_UUID
Changes v3:
- remove unused UUID_STR_BYTE_LEN
- reword comments
- remove null pointer checking from gen_rand_uuid() and gen_rand_uuid_str()
- remove unneeded memset from gen_rand_uuid()
- undo moving vsprintf.o object in lib/Makefile
- add attribute "packed" to the uuid structure
- gen_rand_uuid(): add endian functions for modify uuid data
- gen_rand_uuid(): use memcpy() to store uuid data into given buffer for avoi
unaligned access issues
- change uuid version and variant masks to proper for use with clrsetbits_*
- add #ifdef CONFIG_RANDOM_UUID to random uuid code for avoid warnings
Changes v4:
- add new parameter to define UUID string format for UUID or GUID which differs
in endianness of first three string blocks.
- add uuid structure and version 4 data to uuid header file
- lib/Makefile: add CONFIG_RAND_UUID dependency to rand.o and uuid.o
---
include/common.h | 3 ++-
include/uuid.h | 22 ++++++++++++++++++-
lib/Makefile | 2 ++
lib/uuid.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
4 files changed, 88 insertions(+), 4 deletions(-)
diff --git a/include/common.h b/include/common.h
index 658c326..deb08f2 100644
--- a/include/common.h
+++ b/include/common.h
@@ -830,7 +830,8 @@ char * strmhz(char *buf, unsigned long hz);
/* lib/rand.c */
#if defined(CONFIG_RANDOM_MACADDR) || \
defined(CONFIG_BOOTP_RANDOM_DELAY) || \
- defined(CONFIG_CMD_LINK_LOCAL)
+ defined(CONFIG_CMD_LINK_LOCAL) || \
+ defined(CONFIG_RANDOM_UUID)
#define RAND_MAX -1U
void srand(unsigned int seed);
unsigned int rand(void);
diff --git a/include/uuid.h b/include/uuid.h
index 0d16038..32e592c 100644
--- a/include/uuid.h
+++ b/include/uuid.h
@@ -7,15 +7,35 @@
#ifndef __UUID_H__
#define __UUID_H__
+/* This is structure is in big-endian */
+struct uuid {
+ unsigned int time_low;
+ unsigned short time_mid;
+ unsigned short time_hi_and_version;
+ unsigned char clock_seq_hi_and_reserved;
+ unsigned char clock_seq_low;
+ unsigned char node[6];
+} __packed;
+
typedef enum {
UUID_STR_FORMAT_STD,
UUID_STR_FORMAT_GUID
} uuid_str_t;
#define UUID_STR_LEN 36
-#define UUID_BIN_LEN 16
+#define UUID_BIN_LEN sizeof(struct uuid)
+
+#define UUID_VERSION_MASK 0xf000
+#define UUID_VERSION_SHIFT 12
+#define UUID_VERSION 0x4
+
+#define UUID_VARIANT_MASK 0xc0
+#define UUID_VARIANT_SHIFT 7
+#define UUID_VARIANT 0x1
int uuid_str_valid(const char *uuid);
int uuid_str_to_bin(char *uuid_str, unsigned char *uuid_bin, uuid_str_t format);
void uuid_bin_to_str(unsigned char *uuid_bin, char *uuid_str, uuid_str_t format);
+void gen_rand_uuid(unsigned char *uuid_bin);
+void gen_rand_uuid_str(char *uuid_str, uuid_str_t format);
#endif
diff --git a/lib/Makefile b/lib/Makefile
index 2e8bd20..fd75e80 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -63,6 +63,8 @@ obj-$(CONFIG_TRACE) += trace.o
obj-$(CONFIG_BOOTP_PXE) += uuid.o
obj-$(CONFIG_PARTITION_UUIDS) += uuid.o
obj-y += vsprintf.o
+obj-$(CONFIG_RANDOM_UUID) += uuid.o
+obj-$(CONFIG_RANDOM_UUID) += rand.o
obj-$(CONFIG_RANDOM_MACADDR) += rand.o
obj-$(CONFIG_BOOTP_RANDOM_DELAY) += rand.o
obj-$(CONFIG_CMD_LINK_LOCAL) += rand.o
diff --git a/lib/uuid.c b/lib/uuid.c
index 75a5608..d3ba60e 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -14,8 +14,23 @@
/*
* UUID - Universally Unique IDentifier - 128 bits unique number.
* There are 5 versions and one variant of UUID defined by RFC4122
- * specification. Depends on version uuid number base on a time,
- * host name, MAC address or random data.
+ * specification. Depends on version uuid number base on:
+ * - time, MAC address(v1),
+ * - user ID(v2),
+ * - MD5 of name or URL(v3),
+ * - random data(v4),
+ * - SHA-1 of name or URL(v5),
+ *
+ * This library implements UUID v4.
+ *
+ * Layout of UUID Version 4:
+ * timestamp - 60-bit: time_low, time_mid, time_hi_and_version
+ * version - 4 bit (bit 4 through 7 of the time_hi_and_version)
+ * clock seq - 14 bit: clock_seq_hi_and_reserved, clock_seq_low
+ * variant: - bit 6 and 7 of clock_seq_hi_and_reserved
+ * node - 48 bit
+ * In this version all fields beside 4 bit version are randomly generated.
+ * source: https://www.ietf.org/rfc/rfc4122.txt
*
* UUID binary format (16 bytes):
*
@@ -151,3 +166,49 @@ void uuid_bin_to_str(unsigned char *uuid_bin, char *uuid_str,
}
}
}
+
+/*
+ * gen_rand_uuid() - this function generates a random binary UUID v4.
+ *
+ * @param uuid_bin - pointer to allocated array [16B]. Output is in big endian.
+*/
+#ifdef CONFIG_RANDOM_UUID
+void gen_rand_uuid(unsigned char *uuid_bin)
+{
+ struct uuid uuid;
+ unsigned int *ptr = (unsigned int *)&uuid;
+ int i;
+
+ /* Set all fields randomly */
+ for (i = 0; i < sizeof(struct uuid) / sizeof(*ptr); i++)
+ *(ptr + i) = cpu_to_be32(rand());
+
+ clrsetbits_be16(&uuid.time_hi_and_version,
+ UUID_VERSION_MASK,
+ UUID_VERSION << UUID_VERSION_SHIFT);
+
+ clrsetbits_8(&uuid.clock_seq_hi_and_reserved,
+ UUID_VARIANT_MASK,
+ UUID_VARIANT << UUID_VARIANT_SHIFT);
+
+ memcpy(uuid_bin, &uuid, sizeof(struct uuid));
+}
+
+/*
+ * gen_rand_uuid_str() - this function generates UUID v4 (random) in two string
+ * formats UUID or GUID.
+ *
+ * @param uuid_str - pointer to allocated array [37B].
+ * @param - uuid output type: UUID - 0, GUID - 1
+ */
+void gen_rand_uuid_str(char *uuid_str, uuid_str_t str_format)
+{
+ unsigned char uuid_bin[UUID_BIN_LEN];
+
+ /* Generate UUID (big endian) */
+ gen_rand_uuid(uuid_bin);
+
+ /* Convert UUID bin to UUID or GUID formated STRING */
+ uuid_bin_to_str(uuid_bin, uuid_str, str_format);
+}
+#endif
--
1.9.0
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