ipv6_addr_src_scope
scope = ipv6_addr_src_scope(&ifa6->addr);
scope = ipv6_addr_src_scope(&ifaca6->aca_addr);
scope = ipv6_addr_src_scope(&ifa6->addr);
scope = ipv6_addr_src_scope(&ifaca6->aca_addr);
if (ipv6_addr_src_scope(&a6->sin6_addr) ==
int ifp_scope = ipv6_addr_src_scope(&ifp->addr);
if (ifp_scope >= ipv6_addr_src_scope(&ifa->addr))
ipv6_addr_src_scope(&ifa->addr) != IPV6_ADDR_SCOPE_GLOBAL)