Rob, I have a feeling that this can be accomplished with some manually added match/actions inside of ovs. Specifically using ovs-ofctl. I would add both ports into an ovs bridge Using your criteria to specify the match and action. Writing a flow match by hand involves some trial and error. Something like the following, though I haven't tried it out ovs-ofctl add-flow br0 in_port=0,udp,nw_src=192.168.17.36,nw_dst=172.16.20.3 actions=mod_nw_src:10.0.0.2,mod_nw_dst:10.0.0.1,output:1 This there is a lot of flexibility on matching [1] and the actions [2]. If the network is is full of traffic that you don't care about, you could add a rule to drop a lot of traffic that you don't care about. I hope this helps. [1] https://www.man7.org/linux/man-pages/man7/ovs-fields.7.html [2] https://www.man7.org/linux/man-pages/man7/ovs-actions.7.html On Fri, Oct 25, 2024 at 9:57 AM Rob Roschewsk <rob@xxxxxxxxx> wrote: > > Thanks Martin! > > I'm not at the point of adding code to this project yet ... close but > not yet :) This will certainly give me a head start if that happens. > -> Rob > > > On Fri, Oct 25, 2024 at 4:39 AM Martin Tonusoo <martin@xxxxxxxxxx> wrote: > > > > Hi Rob, > > > > perhaps something like this will do: > > https://gist.github.com/tonusoo/0490bc5cf564689f3999f1de4eef098d > > > > On Debian based distributions the dependencies can be installed with > > "apt install --no-install-recommends python3-pcapy python3-scapy". > > Pcapy is a wrapper library for libpcap which processes the filter in > > Berkeley Packet Filter syntax, builds the binary bytecode and > > eventually sends it to the kernel via the SO_ATTACH_FILTER. Thus, > > there should be very little impact on throughput or CPU usage. > > > > I used a following systemd service to manage the script: > > > > root@deb12-1:~# systemctl cat packet-forwarder > > # /etc/systemd/system/packet-forwarder.service > > [Unit] > > Description=Forwards certain packets received on eth0 out from eth1 > > After=network.target > > > > [Service] > > Type=simple > > Restart=always > > ExecStart=/usr/local/sbin/packet-forwarder.py > > > > [Install] > > WantedBy=multi-user.target > > root@deb12-1:~# > > > > > > Martin > -- Logan
