RTF_PREFIX_RT
RTF_ADDRCONF | RTF_PREFIX_RT,
int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
if (!(rt->fib6_flags & (RTF_ADDRCONF | RTF_PREFIX_RT)) &&
iter->fib6_flags &= ~RTF_PREFIX_RT;
!(rt->fib6_flags & RTF_PREFIX_RT)) {