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ETHER_GEN_ADDR(9) FreeBSD Kernel Developer's Manual ETHER_GEN_ADDR(9)
NAME
ether_gen_addr - generate an arbitrary MAC address for use
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/ethernet.h>
void
ether_gen_addr(struct ifnet *ifp, struct ether_addr *hwaddr);
DESCRIPTION
The ether_gen_addr() function generates an arbitrary MAC address for use
by an ethernet interface that does not have an assigned address.
By default, ether_gen_addr attempts to generate a stable MAC address
using the hostid of the jail that the ifp is being added to. During
early boot, the hostid may not be set on machines that haven't yet
populated /etc/hostid, or on machines that do not use loader(8).
ether_gen_addr can fail to derive a MAC address due to memory allocation
failure, or because the hostid has not been populated. In these cases, a
locally-administered unicast MAC address will be randomly generated and
returned via the hwaddr parameter.
If ether_gen_addr succeeds, then it will return a MAC address in the
FreeBSD Foundation OUI, "58:9c:fc", via the hwaddr parameter.
AUTHORS
This manual page was written by Kyle Evans <kevans@FreeBSD.org>.
FreeBSD 14.0-RELEASE-p6 June 1, 2021 FreeBSD 14.0-RELEASE-p6