we now update /net/ndb with the following information gathered
from router advertisements (rfc6106 and plan9 specific options):
- recursive dns servers (option 25, ndb: dns=)
- dns search list (option 31, ndb: dnsdomain=)
- plan9 fileserver (option 250, ndb: fs=)
- plan9 authserver (option 251, ndb: auth=)
note the plan9 specific options can be disabled with the -G flag.
for ndbconfig (-N flag), we now collect all ip addresses in ndb
belonging to the devices mac address and configue them all. v6
addresses are getting added when a link local address exists
or the -6 flag has been specified to automatically configure one.
move the dhcp code in its own dhcp.c file and make symbols static
that are not used across modules.
