Mwan3 restart cause message from kernel "RTNETLINK answers: file exists"

I have set two different ipv6 subnet in one device. And add these two interface in mwan3 configuration.

/etc/config/network:

config interface 'cloud_wan3'
        option ifname 'eth1'
        option proto 'static'
        option ipv6 '1'
        option metric '10'
        option ip6addr 'fdb1:3dd8:e465::2/60'
        option ip6gw 'fdb1:3dd8:e465::1'

config interface 'cloud_wan4'
        option ifname 'eth2'
        option proto 'static'
        option ipv6 '1'
        option metric '20'
        option ip6addr 'fdb1:3dd8:e466::2/60'
        option ip6gw 'fdb1:3dd8:e466::1'

/etc/config/mwan3:

config interface 'cloud_wan3'
        option enabled '1'
        option initial_state 'online'
        option family 'ipv6'
        option track_method 'ping'
        option reliability '1'
        option count '1'
        option size '56'
        option check_quality '0'
        option timeout '2'
        option interval '5'
        option failure_interval '5'
        option recovery_interval '5'
        option down '3'
        option up '3'
        #option flush_conntrack 'never'

config interface 'cloud_wan4'
        option enabled '1'
        option initial_state 'online'
        option family 'ipv6'
        option track_method 'ping'
        option reliability '1'
        option count '1'
        option size '56'
        option check_quality '0'
        option timeout '2'
        option interval '5'
        option failure_interval '5'
        option recovery_interval '5'
        option down '3'
        option up '3'
        #option flush_conntrack 'never'

After doing network restart, I see the ipv6 routing table works.

fdb1:3dd8:e465::/60 dev eth1 proto static metric 10 pref medium
fdb1:3dd8:e466::/60 dev eth2 proto static metric 20 pref medium
fe80::/64 dev br-edge_lan proto kernel metric 256 pref medium
fe80::/64 dev br-mgmt_xcc_lan proto kernel metric 256 pref medium
fe80::/64 dev br-x86_lan proto kernel metric 256 pref medium
fe80::/64 dev eth1 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
default via fdb1:3dd8:e465::1 dev eth1 proto static metric 10 pref medium
default via fdb1:3dd8:e466::1 dev eth2 proto static metric 20 pref medium

But after doing mwan3 restart, I see the twelve "RTNETLINK answers: File exists"

After checking the /lib/mwan3/mwan3.sh, point is at this line: $IP6 route add table $tid $line in function mwan3_rtmon_ipv6().
This add the ipv6 link local address into the ipv6 routing table again but without delete first.
This messages will not affect the function of mwan3. But is it correct to add link local address into routing table again?

My guess is you’ve found the cause.

“Proper”? If I were to be trying to “fix” it, my first instinct would be to question if routes were removed properly on shutdown. If so, I’d consider either a conditional or maybe route replace instead of route add. I don’t know enough of the detailed operation to know what’s “right”.

Hi Jeff,

If I do "ifdown cloud_wan2" and "ifdown cloud_wan4", I see the routing entry of eth2 is removed properly. The routing table works fine.

1 Like