[ovs-dev] [PATCH] datapath: Add a new action dec_ttl

[Eelco Chaudron]

Please ignore this one, as I forgot to add the v2 tag. A new one was 
sent, and patchwork is updated!

//Eelco


On 13 Nov 2020, at 10:58, Eelco Chaudron wrote:

> Add support for the dec_ttl action. Instead of programming the 
> datapath with
> a flow that matches the packet TTL and an IP set, use a single dec_ttl 
> action.
>
> The old behavior is kept if the new action is not supported by the 
> datapath.
>
>   # ovs-ofctl dump-flows br0
>    cookie=0x0, duration=12.538s, table=0, n_packets=4, n_bytes=392, ip 
> actions=dec_ttl,NORMAL
>    cookie=0x0, duration=12.536s, table=0, n_packets=4, n_bytes=168, 
> actions=NORMAL
>
>   # ping -c1 -t 20 192.168.0.2
>   PING 192.168.0.2 (192.168.0.2) 56(84) bytes of data.
>   IP (tos 0x0, ttl 19, id 45336, offset 0, flags [DF], proto ICMP (1), 
> length 84)
>       192.168.0.1 > 192.168.0.2: ICMP echo request, id 8865, seq 1, 
> length 64
>
> Linux netlink datapath support depends on upstream Linux commit:
>   744676e77720 ("openvswitch: add TTL decrement action")
>
>
> Note that in the Linux kernel tree the OVS_ACTION_ATTR_ADD_MPLS has 
> been
> defined, and to make sure the IDs are in sync, it had to be added to 
> the
> OVS source tree. This required some additional case statements, which
> should be revisited once the OVS implementation is added.
>
>
> Co-developed-by: Matteo Croce <mcroce at linux.microsoft.com>
> Co-developed-by: Bindiya Kurle <bindiyakurle at gmail.com>
> Signed-off-by: Eelco Chaudron <echaudro at redhat.com>