Problem with routes when configuring IPv6 addresses

[Jan Mikael Melen]

Hello,

I previously already sent this to the freebsd-net list but didn't get any 
response so let's try the hackers list instead.

I have a problem with routes in 6.1 when configuring IPv6 address using both
autoconfigured addresses at the same time with statically configured
addresses from different prefixes.

If the host is not accepting router advertisements everything seems to work
fine:
# sysctl -a | grep rtad
net.inet6.ip6.accept_rtadv: 0
# ifconfig fxp0 inet6 3ffe:101::1 prefixlen 64

# netstat -rn -f inet6 | grep 3ffe:101
3ffe:101::/64                     link#1                        UC
fxp0
3ffe:101::1                       00:12:3f:71:3e:ef             UHL
lo0
#

As you can see I have two routes one for the loopback and one for the prefix
as it should GREAT!

Now if I'll set the host to accept router advertisements then the route for
the 3ffe:101:: prefix will be deleted as the first router advertisement is
received. The router advertises prefix 3ffe:14b8:400:101::/64.

# sysctl net.inet6.ip6.accept_rtadv=1
net.inet6.ip6.accept_rtadv: 0 -> 1
# rtsol -a
# netstat -rn -f inet6 | grep 3ffe:101
3ffe:101::1                       00:12:3f:71:3e:ef             UHL
lo0
#

It seems that the route is deleted because in function pfxlist_onlink_check()
there is a check that if the state has changed to DETACHED the
nd6_prefix_offlink will be called which then removes the route:
	if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
	    (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
		if ((e = nd6_prefix_offlink(pr)) != 0) {
			nd6log((LOG_ERR,
			    "pfxlist_onlink_check: failed to "
			    "make %s/%d offlink, errno=%d\n",
			    ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
			    pr->ndpr_plen, e));
		}
	}

This far I digged in to the code but then ran out of steam :-( Obviously the
state should not be set to DETACHED for manually configured prefixes but the
question is rather where it should be done.

Before somebody asks, if I first do the autoconfiguration part and then after
I have the autoconfigured address add the manually configured address the
result is that there wont be any route for the manually configured prefix
(3ffe:101::/64).

  Regards,
     Jan