V_ipport_hifirstauto
if (port != 0 && (port < V_ipport_hifirstauto ||
uh->uh_sport |= htons(V_ipport_hifirstauto) |
RANGECHK(V_ipport_hifirstauto, IPPORT_RESERVED, IPPORT_MAX);
first = V_ipport_hifirstauto; /* sysctl */