Use NDP option serializer instead of handcrafting the NS
Use NDP option serializer instead of handcrafting the NS

Use the correct constant (Solicit, not Advert) while I'm here.

PiperOrigin-RevId: 336924605

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor