NDP Neighbor Solicitations sent during Duplicate Address Detection must have an IP hop limit of 255, as all NDP Neighbor Solicitations should have. Test: Test that DAD messages have the IPv6 hop limit field set to 255. PiperOrigin-RevId: 275321680
Also removes the need for protocol names. PiperOrigin-RevId: 271186030
PiperOrigin-RevId: 267709597
Make sure that NDP packets are only received if their IP header's hop limit field is set to 255, as per RFC 4861. PiperOrigin-RevId: 267061457