MPLS decap with iproute2

MPLS decap with iproute2

[Sam Russell]

Hi,

I've had success with the iproute2 manpage example for encapsulating
outgoing traffic in MPLS, but I've not found a way to add decap routes
inbound.

I've tried "ip route -f mpls add 100 dev lo" and other variations, but I
get netlink errors back.

Has this been built yet? Is there sample config that I can try out? I'm
running a home-built 4.3 kernel + iproute2 built from head (on ubuntu
15.10) and am comfortable with perf and splashing around in the codebase if
need be.

Cheers
Sam

Re: MPLS decap with iproute2

[Robert Shearman]

On 07/12/15 19:42, Sam Russell wrote:
> Hi,
>
> I've had success with the iproute2 manpage example for encapsulating
> outgoing traffic in MPLS, but I've not found a way to add decap routes
> inbound.
>
> I've tried "ip route -f mpls add 100 dev lo" and other variations, but I
> get netlink errors back.
>
> Has this been built yet? Is there sample config that I can try out? I'm
> running a home-built 4.3 kernel + iproute2 built from head (on ubuntu
> 15.10) and am comfortable with perf and splashing around in the codebase if
> need be.

Hi Sam,

This certainly works on net-next, albeit with a bug on the subsequent 
"ip route -f mpls list" that I'll shortly be sending a patch for.

Have you first set an appropriate label table size? E.g.:

   $ sysctl net.mpls.platform_labels=1048575

If you intend to receive non-BOS traffic over your route above, then you 
should also make sure to enable mpls input on lo (and your actual input 
interfaces), otherwise the traffic will be dropped.

Thanks,
Rob

Re: MPLS decap with iproute2

[Sam Russell]

Hi Robert,

Thanks for the tip, I'll give it a shot when I get home this evening (UTC+13).
I'm planning to put together a blog on how to manually string up an
MPLS l3vpn, to help people start playing with the new MPLS support now
that it's finally in the mainline kernel.

Cheers
Sam

Re: MPLS decap with iproute2

[roopa]

On 12/7/15, 11:42 AM, Sam Russell wrote:
> Hi,
>
> I've had success with the iproute2 manpage example for encapsulating
> outgoing traffic in MPLS, but I've not found a way to add decap routes
> inbound.
>
> I've tried "ip route -f mpls add 100 dev lo" and other variations, but I
> get netlink errors back.
>
> Has this been built yet? Is there sample config that I can try out? I'm
> running a home-built 4.3 kernel + iproute2 built from head (on ubuntu
> 15.10) and am comfortable with perf and splashing around in the codebase if
> need be.
>
Example below should work
 ip -f mpls route add 100 as 200 via inet 10.1.1.2 dev eth0

You have to enable mpls on the interface first:
echo 1 > /proc/sys/net/mpls/conf/eth0/input

multipath iproute2 patches are not in yet. Will submit them soon.

let me know if you still get errors.

Re: MPLS decap with iproute2

[Sam Russell]

Thanks all for your help, I got it working with Robert and Roopa's
sysctl settings, the following works:

ip route -f mpls add 100 dev lo

On 8 December 2015 at 15:37, roopa <roopa@cumulusnetworks.com> wrote:
> On 12/7/15, 11:42 AM, Sam Russell wrote:
>> Hi,
>>
>> I've had success with the iproute2 manpage example for encapsulating
>> outgoing traffic in MPLS, but I've not found a way to add decap routes
>> inbound.
>>
>> I've tried "ip route -f mpls add 100 dev lo" and other variations, but I
>> get netlink errors back.
>>
>> Has this been built yet? Is there sample config that I can try out? I'm
>> running a home-built 4.3 kernel + iproute2 built from head (on ubuntu
>> 15.10) and am comfortable with perf and splashing around in the codebase if
>> need be.
>>
> Example below should work
>  ip -f mpls route add 100 as 200 via inet 10.1.1.2 dev eth0
>
> You have to enable mpls on the interface first:
> echo 1 > /proc/sys/net/mpls/conf/eth0/input
>
> multipath iproute2 patches are not in yet. Will submit them soon.
>
> let me know if you still get errors.

Re: MPLS decap with iproute2

[David Ahern]

On 12/7/15 2:50 PM, Sam Russell wrote:
> Hi Robert,
>
> Thanks for the tip, I'll give it a shot when I get home this evening (UTC+13).
> I'm planning to put together a blog on how to manually string up an
> MPLS l3vpn, to help people start playing with the new MPLS support now
> that it's finally in the mainline kernel.
>

FWIW, I have demo of this topology with MPLS + VRFs for the VRF tutorial 
at netdev1.1:

h       +--------+                                    +--------+      h
o  -----|        |                                    |        |----- o
s   ... |  c1e1  |-----+                        +-----|  c1e2  | ...  s
t  -----|        |     |                        |     |        |----- t
s       +--------+     |                        |     +--------+      s
                     +-------+              +-------+
                     |       |   +------+   |       |
                     |  pe1  |---|  pe  |---|  pe2  |
                     |       |   +------+   |       |
                     +-------+              +-------+
h       +--------+     |                        |     +--------+      h
o  -----|        |     |                        |     |        |----- o
s   ... |  c2e1  |-----+                        +-----|  c2e2  | ...  s
t  -----|        |                                    |        |----- t
s       +--------+      \----------------------/      +--------+      s
                            provider backbone