Generate system wide (locally) unique IDs. More...
Generate system wide (locally) unique IDs.
This module generates system wide, variable length unique IDs based on on the cpuid module. If the cpuid module is not present, the module falls back to a pre-defined, constant seed for creating unique IDs.
The main purpose of this module is to have a unified way for e.g. creating hardware addresses and similar.
The IDs generated by this module are base created from a constant base part and a dynamic portion, which is XORed into the base ID. If the cpuid module is present, the base ID is created from the CPU's unique ID. If not, the base ID is created by simple 'memsetting' the base ID with the defined backup seed value.
Once the base ID is generated, a LUID is generated by (i) XORing a counter value with the LSB of the base ID, or (ii) by XORing the least significant byes with a value given by the user.
Example: Calling luid_base(&buf, 8)
will always yield an identical value, independent how often the function is called. But calling luid_base(&buf, 2)
afterwards will results in a different value, if the cpuid module is present, and in the same (but shorter) value if not.
Example: Calling luid_get(&buf, 8)
four times in a row, will yield four different IDs, differing in their LSB.
Example: Calling luid_custom(&buf, 8, 123)
will always yield the same value, but calling luid_custom(&buf, 8, 124)
will differ.
Files | |
file | luid.h |
Header of the unique ID generation module. | |
Macros | |
#define | LUID_BACKUP_SEED 0x23 |
Value used as based for the LUIDs in case the cpuid module is not present. | |
Functions | |
void | luid_get (void *buf, size_t len) |
Get a unique ID. | |
void | luid_get_lb (void *buf, size_t len) |
Get a unique ID with change in the last byte. | |
void | luid_get_short (network_uint16_t *addr) |
Get a unique short unicast address. | |
void | luid_get_eui48 (eui48_t *addr) |
Get a unique EUI48 address. | |
void | luid_netdev_get_eui48 (const netdev_t *netdev, eui48_t *addr) |
Get a unique EUI48 address. | |
void | luid_get_eui64 (eui64_t *addr) |
Get a unique EUI64 address. | |
void | luid_netdev_get_eui64 (const netdev_t *netdev, eui64_t *addr) |
Get a unique EUI64 address. | |
void | luid_custom (void *buf, size_t len, int gen) |
Get a custom unique ID based on a user given generator value. | |
void | luid_base (void *buf, size_t len) |
Get a LUID base value. | |
#define LUID_BACKUP_SEED 0x23 |
void luid_base | ( | void * | buf, |
size_t | len | ||
) |
Get a LUID base value.
The luid module creates the value dependent on the given len
value using the cpuid module if present or a static seed value (LUID_BACKUP_SEED) if not.
[out] | buf | memory location to copy the LUID into. MUST be able to hold at least len bytes |
[in] | len | length of the LUID in bytes |
void luid_custom | ( | void * | buf, |
size_t | len, | ||
int | gen | ||
) |
Get a custom unique ID based on a user given generator value.
The resulting ID is built from the base ID XORed with gen
in the base ID's most significant bytes.
gen
and len
will always result in identical LUIDs.[out] | buf | memory location to copy the LUID into. MUST be able to hold at least len bytes |
[in] | len | length of the LUID in bytes |
[in] | gen | custom LUID generator value |
void luid_get | ( | void * | buf, |
size_t | len | ||
) |
Get a unique ID.
The resulting ID is built from the base ID generated with luid_base(), which isXORed with an 8-bit incrementing counter value into the first (lowest index) byte.
[out] | buf | memory location to copy the LUID into. MUST be able to hold at least len bytes |
[in] | len | length of the LUID in bytes |
void luid_get_eui48 | ( | eui48_t * | addr | ) |
Get a unique EUI48 address.
The resulting address is built from the base ID generated with luid_base(), which isXORed with an 8-bit incrementing counter value into the least significant byte.
[out] | addr | memory location to copy the address into. |
void luid_get_eui64 | ( | eui64_t * | addr | ) |
Get a unique EUI64 address.
The resulting address is built from the base ID generated with luid_base(), which isXORed with an 8-bit incrementing counter value into the least significant byte.
[out] | addr | memory location to copy the address into. |
void luid_get_lb | ( | void * | buf, |
size_t | len | ||
) |
Get a unique ID with change in the last byte.
The resulting ID is built from the base ID generated with luid_base(), which isXORed with an 8-bit incrementing counter value into the last (highest index) byte.
[out] | buf | memory location to copy the LUID into. MUST be able to hold at least len bytes |
[in] | len | length of the LUID in bytes |
void luid_get_short | ( | network_uint16_t * | addr | ) |
Get a unique short unicast address.
The resulting address is built from the base ID generated with luid_base(), which isXORed with an 8-bit incrementing counter value into the least significant byte.
[out] | addr | memory location to copy the address into. |
Get a unique EUI48 address.
The resulting address is built from the base ID generated with luid_base(), which isXORed with the netdev type and netdev index in the least significant bytes.
[in] | netdev | Netdev to generate the EUI48 for. |
[out] | addr | memory location to copy the address into. |
Get a unique EUI64 address.
The resulting address is built from the base ID generated with luid_base(), which isXORed with the netdev type and netdev index in the least significant bytes.
[in] | netdev | Netdev to generate the EUI64 for. |
[out] | addr | memory location to copy the address into. |