XPost: linux.debian.bugs.dist   
   From: csmate@nop.hu   
      
   hi,   
      
   On 10/21/25 15:02, Jason Xing wrote:   
   >> if you're in a need for some more complicated xsk tests, just let me know,   
   freertr   
   >>   
   >> have a dataplane and a socat-alike tool with an xsk based packetio for a   
   while....   
   >   
   > Could you provide a link that points to what you just mentioned? I   
   > believe more tests on veth are necessary.   
   >   
      
   sure, but be warned, it's a huge rabbit-hole that you're jumping into.... :)   
      
   so the homepage is freertr.org, it provides a daily vm builds...   
      
   if you grab the qcow2, convert to raw and mount -o offset=1048576   
      
   you can update the kernel and initrd, and you need to put the xdp   
      
   bpf and elf libs as they're not part of that image... then umount it,   
      
   and after the first boot (look at the serial console!), do the following:   
      
   conf t   
   int eth1   
     vrf forwarding host   
     ipv4 addr 10.0.2.222 255.255.255.0   
     exit   
   ipv4 route host 0.0.0.0 0.0.0.0 10.0.2.2   
   end   
   write   
   test hwext path /rtr/rtr- dataplane p4xsk   
   reload cold   
   y   
      
   your xdp dataplath is activated, the vm kernel itself will be behind   
      
   a veth pair, the dataplane will play with the qemu virtio-pci and the veth,   
      
   and there will be an other veth for the dataplane-controlplane communication   
      
   full of random non-ip frames, then   
      
   ping 10.255.255.1 vrf host   
      
   ping 10.0.2.2 vrf host   
      
   will test for the fresh kernel and the outside word...   
      
   you can exercise the above with a raw socket on the original image if you do   
   "p4raw"   
      
   instead of "p4xsk", and as we're on the bpf, it have an in-kernel forwarder   
   called "p4xdp"....:)   
      
      
      
   the source is at https://github.com/mc36/freeRtr , the misc/native folder   
      
   contains the dataplane, and the socat-alike tools.... just ./c.sh to build   
   them...   
      
      
   afterwards you can create topologies with then like   
      
   (1.1.1.1/30)ns1-----------host-----------ns2(1.1.1.2/30)   
      
   to cross connect 2 interfaces on the host, just run 2 processes like   
      
   xskInt.bin veth1 skb 1234 127.0.0.1 4321 127.0.0.1   
      
   pcapInt.bin veth2 4321 127.0.0.1 1234 127.0.0.1   
      
   there are other tools with uring, raw socket, mmaped raw socket   
      
   and some others that are uninterested in the current topic imho....   
      
      
   have a nice day,   
      
   csaba   
      
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