[ovs-discuss] Conntrack and unexpected change in source IP

[Thiago Santos]

Hello,

I've been using OVS Conntrack integration for Source NAT and setting the
Destination IP directly but this is having the side effect of overwriting
the Conntrack set SNAT IP. I simplified my rules to look like this to
reproduce the problem:

cookie=0x0, duration=90070.633s, table=0, n_packets=32266,
n_bytes=48644792, idle_age=1716, hard_age=65534,
ip,in_port=1,nw_dst=1.1.1.2 actions=ct(table=1,zone=2,nat)
cookie=0x0, duration=89993.501s, table=1, n_packets=32266,
n_bytes=48644792, idle_age=1716, hard_age=65534,
ct_state=+new+trk,ip,in_port=1,nw_dst=1.1.1.2
actions=ct(commit,zone=2,nat(src=10.1.1.1)),resubmit(,2)
cookie=0x0, duration=1757.194s, table=2, n_packets=0, n_bytes=0,
idle_age=1757, priority=601,ip,nw_src=10.10.10.10 actions=drop
cookie=0x0, duration=1808.236s, table=2, n_packets=5361, n_bytes=8105832,
idle_age=1716, priority=600,ip actions=mod_nw_dst:10.1.1.2,output:2

If I change the last 2 rules priorities so that they are in reverse order,
it seems to work.

ovs-appctl dpctl/dump-flows shows me this:
recirc_id(0x2),ct_state(+new+trk),eth(),eth_type(0x0800),ipv4(src=
0.0.0.0/248.0.0.0,dst=1.1.1.2,frag=no), packets:59, bytes:89208,
used:0.168s, actions:ct(commit,zone=2,nat(src=10.1.1.1)),set(ipv4(src=
0.0.0.0/248.0.0.0,dst=10.1.1.2)),4

So it looks like it is doing a set on the source IP because of the matching
on source IP of the 3rd rule above. Is there a way around this or am I
doing something wrong?

Thanks,
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