the dnsquery() library function should not start mouting /srv/dns on
its own. this problem arrises only for ndb/cs as it is started before
ndb/dns.
the issue with mounting /srv/dns before /net is when ndb/cs attempts
to read the list of interfaces, accessing /net/ipifc, which triggers
a rpc to ndb/dns as it is ontop of the mount. this can yield a deadlock
when ndb/dns blocks its 9p loop waiting for requests to complete on
a refresh and the requests are stuck waiting for ndb/cs to translate
a dial string for announce().
dblookup() used to only return the first matching entry. in
case of ipv6, we want all entries returned to get both v4
and v6 addresses... and these might not neccesarily be in
the same entry (see /lib/ndb/common). note also this makes
it behave the same as in cachedb mode which reads in the
whole database.
we do not know if v4 or v6 routing works, so the simplest
is just to query v4 and v6 nameservers in parallel. this is
done by changing serveraddrs() to return one address type,
and we make sure to get at least one v4 and one v6 address
each round.
get rid of the weigthed timeout code... there where too many
assumptions. instead, we give a round 500ms timeout (or 1 second
in patient mode) and honor the maximum query time.
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.
we have to maintain the ->line chain for ndbreorder() to work, so add
a little helper: ndbline() which replicates the ->entry chain and links
the last tuple to the first; makeing the whole list into a single line.
