[ovs-discuss] GRE over IPv6 configuration

Ben Pfaff blp at ovn.org
Tue Jun 4 18:38:09 UTC 2019


On Tue, Jun 04, 2019 at 06:08:00PM +0000, Eli Britstein wrote:
> 
> On 6/4/2019 8:24 PM, Ben Pfaff wrote:
> > On Tue, Jun 04, 2019 at 03:13:02PM +0000, Eli Britstein wrote:
> >> Hello,
> >>
> >> I would like to configure a GRE tunnel over IPv6, on a Linux system.
> >> However, I encounter the following:
> >>
> >> My command:
> >> ovs-vsctl add-port br1 gre6 -- set interface gre6 type=ip6gre
> >> options:remote_ip= 2001:db8:0:f102::11 options:key=55
> >>
> >> Output:
> >> ovs-vsctl: Error detected while setting up 'gre6': could not add network
> >> device gre6 to ofproto (Address family not supported by protocol).  See
> >> ovs-vswitchd log for details.
> >> ovs-vsctl: The default log directory is "/var/log/openvswitch".
> >>
> >> In the log:
> >> bridge|WARN|could not add network device gre6 to ofproto (Address family
> >> not supported by protocol)
> >>
> >> I notice that if I want to define a ip6gretap with “ip link”, there is a
> >> need to use “-6” option, to set the correct family.
> >>
> >> Is there a way to note the correct family (though I think should be
> >> implicit by “ip6gre”)? Or maybe some other configuration?
> > OVS doesn't have an "ip6gre" interface type.  Just use "gre".
> 
> I see it does in lib/netdev-vport.c, line 1222. Isn't that ip6gre?

Um, that's weird.  We don't document it.  I thought for sure that we
tried to make our "regular" tunnels just accept both IPv4 and IPv6
addresses.

Greg, I see that you're the author of ip6gre (and ip6erspan).  Can you
comment on the intentions?  If ip6gre is indeed the right way to
configure a GRE-over-IPv6 tunnel, then we should document it.  I guess
the same goes for ip6erspan since I don't see any documentation for that
either.

Also, can you take a look at Eli's report below and perhaps give him
some tips?

> Anyway, indeed trying with just "gre" the configuration passes OK. 
> However, I don't see any traffic on the other machine.
> 
>          Port "gre6"
>              Interface "gre6"
>                  type: gre
>                  options: {key="55", local_ip="2001:db8:0:f102::f0", 
> remote_ip="2001:db8:0:f102::f1"}
> 
> $ ping 2001:db8:0:f102::f1
> PING 2001:db8:0:f102::f1(2001:db8:0:f102::f1) 56 data bytes
> 64 bytes from 2001:db8:0:f102::f1: icmp_seq=1 ttl=64 time=0.440 ms
> 64 bytes from 2001:db8:0:f102::f1: icmp_seq=2 ttl=64 time=0.072 ms
> 
> I even configured an explicit OF rule to redirect to the gre6 port. I 
> see it is hit, but still no traffic.
> 
> Do I have to configure explicit routes or something of that kind?
> 


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