Function if_setlladdr

freebsd/net/if.c:3784–3834

* Set the link layer address on an interface. * * At this time we only support certain types of interfaces, * and we don't allow the length of the address to change. * * Set noinline to be dtrace-friendly */

 * Set noinline to be dtrace-friendly
 */
__noinline int
if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
{
	struct sockaddr_dl *sdl;
	struct ifaddr *ifa;
	struct ifreq ifr;

	ifa = ifp->if_addr;
	if (ifa == NULL)
		return (EINVAL);

	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
	if (sdl == NULL)
		return (EINVAL);

	if (len != sdl->sdl_alen)	/* don't allow length to change */
		return (EINVAL);

	switch (ifp->if_type) {
	case IFT_ETHER:
	case IFT_XETHER:
	case IFT_L2VLAN:
	case IFT_BRIDGE:
	case IFT_IEEE8023ADLAG:
		bcopy(lladdr, LLADDR(sdl), len);
		break;
	default:
		return (ENODEV);
	}

	/*
	 * If the interface is already up, we need
	 * to re-init it in order to reprogram its
	 * address filter.
	 */
	if ((ifp->if_flags & IFF_UP) != 0) {
		if (ifp->if_ioctl) {
			ifp->if_flags &= ~IFF_UP;
			ifr.ifr_flags = ifp->if_flags & 0xffff;
			ifr.ifr_flagshigh = ifp->if_flags >> 16;
			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
			ifp->if_flags |= IFF_UP;
			ifr.ifr_flags = ifp->if_flags & 0xffff;
			ifr.ifr_flagshigh = ifp->if_flags >> 16;
			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
		}
	}
	EVENTHANDLER_INVOKE(iflladdr_event, ifp);

	return (0);
}

/*
 * Compat function for handling basic encapsulation requests.