Use case understanding for l3fwd

[J.J. Martzki]

> Is this process correct to assign IP  and then device to DPDK?
No, after binding the driver to vfio/uio, the IP configuration is no
longer available.
The IP is something belonging to an application, not a driver (DPDK).

> Is there any way to see ip and ethernet address after binding to DPDK?
MAC is available for the rte_eth_dev, there's some API like
rte_eth_macaddr_get() to get MAC
from a specific port. l3fwd should have some CLI commands for getting
MAC ethier, maybe
you can read it's documents.
IP is not available as I said before.

BTW, your topo is confusing. Are you running 2 l3fwd in 2 separate
VMs? It's not gonna work.
AFAK, l3fwd switches packets from ports which attached to it. You
can't use 2 separate l3fwd
to connect 2 VMs.

If you are tring to connect 2 VMs, the classic topo is something like:
|       VM1       |                          HOST
     |        VM2       |
app <- device -> qemu <- pmd -> l3fwd <- pmd -> qemu <- device -> app

J.J. Martzki,
Best wishes.

Dinesh Kumar <raidinesh at utexas.edu> 于2023年4月14日周五 01:32写道：
>
> Hello Experts,
>
> I am trying to run the following scenario using l3fwd example in dpdk-stable-21.11.2 release .
>
> The flow is :
>
>          VM1                                                                                                 VM2
> ns0->tap0<IPV4 IP>->DPDK       <--------------------->  DPDK-> bind a device  with IP <IPV4 IP >
>
>
> The first question I have for VM2:
> I assigned IP to the device and can see eth and static ip address via  'ip add ', then after binding it to dpdk, I can not see this information via ip add because it is not controlled by kernel module.
> Is there any way to see ip and ethernet address after binding to DPDK?
> Is this process correct to assign IP  and then device to DPDK?
>
>
> on VM1:
>  After starting the DPDK application, I can see a tap0 device created in kernel mode via 'ip add show'.Then I attached this interface with network namespace via:
>
> ip netns add ns0
> ip link set tap0 netns ns0
> ip netns exec ns0 ip addr add <IPV4 Address> dev tap0
> ip netns exec ns0 ip link set tap0 up
> ip netns exec ns0 ip link set lo up
>
> Still, I am not able to ping anything from this ns0.
>
> Do I need any other configuration to ping via ns0 to VM2?
>
> Sorry, in case I am asking any dumb questions, I am new to DPDK and trying to make the use case work.
> Any help/pointer is really appreciated.
>
>