PF_LINK
#ifdef PF_LINK
{ PF_LINK, "link" },
NULL, 0, NULL, 0, CTL_NET, PF_LINK, CTL_EOL)) != 0)
NULL, 0, NULL, 0, CTL_NET, PF_LINK, CTL_EOL)) != 0)
s = socket(PF_LINK, SOCK_DGRAM, 0);
s = socket(PF_LINK, SOCK_DGRAM, 0);