Bug#815793: IPv6 code ignores unsolicited router advertisements

[Martin Pitt]

Hello Marc,

Marc Haber [2016-07-06  9:42 +0200]:
> I think this particular issue can be triggered by:
> 
> - set up a router running radvd
> - start up a client with networkd and systemd IPv6 implementation
> - manually remove any IPv6 address and IPv6 route from the client
> - restart the radvd on the router
> 
> The client should pick up the prefix and route that the newly started
> radvd announces. At least this would be my first test.

I did that now:

| ip link add name enc type veth peer name ens
| ip a add 2600::1/64 dev ens
| ip  link set ens up
|
| cat <<EOF > /tmp/ra.conf
| interface ens
| {
|    AdvSendAdvert on;
|    prefix 2600::1/64
|    {};
| };
| EOF
|
| radvd -C /tmp/ra.conf -n -m stderr -d2

Other terminal:

| mkdir -p /run/systemd/network
| cat <<EOF > /run/systemd/network/enc.network
| [Match]
| Name=enc
| 
| [Network]
| IPv6AcceptRouterAdvertisements=yes
| EOF
| 
| SYSTEMD_LOG_LEVEL=debug /lib/systemd/systemd-networkd

I also ran "tcpdump -i ens" in parallel, as before. This does the
solicitation and picks up radvd's RA and I get some random 2600:*
address:

| Disc CLIENT: Received Router Advertisement: flags none preference medium lifetime 1800 sec
| NDisc CLIENT: Update prefix 2600:0000:0000:0000:0000:0000:0000:0001/64 lifetime 86400 expires in 1d
| ens: Updating address: 2600::7852:45ff:fed7:9ab4/64 (valid for 1d)

I now killed radvd, then "ip a del 2600:[..] dev enc", and restart
radvd. And once again networkd picks this up and adds an IPv6 address.

This looks the same for 229, 230/upstream and 230/sid (with the
reverted patch). Thus I cannot confirm that networkd ignores these
unsolicited router advertisements.

So re-trying with my test packages and getting a networkd debug log
would be appreciated. Thanks!

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)