RDMA header inspection

RDMA header inspection

[Dimitris Dimitropoulos]

Hi,

I'm trying to inspect RDMA headers and they do not show up on
wireshark. How can I observe RDMA headers ? Also, any header parser
available in the code base that I can link to and use to process the
headers ?


Thank you.

Dimitris

Re: RDMA header inspection

[Mark Bloch]

On 2/3/20 11:30 AM, Dimitris Dimitropoulos wrote:
> Hi,
> 
> I'm trying to inspect RDMA headers and they do not show up on
> wireshark. How can I observe RDMA headers ? Also, any header parser
> available in the code base that I can link to and use to process the
> headers ?

Usually RDMA packets will not be seen by the end nodes.
What is the link layer IB or RoCE?
If RoCE and you have a switch in the middle, you can probably run wireshark/tcpdump there.

If you are using a driver that implements the right flow steering API you could use libpcap:
https://github.com/the-tcpdump-group/libpcap

The APIs used:
https://github.com/the-tcpdump-group/libpcap/blob/master/pcap-rdmasniff.c

> 
> 
> Thank you.
> 
> Dimitris
> 

Mark

Re: RDMA header inspection

[Leon Romanovsky]

On Mon, Feb 03, 2020 at 11:30:09AM -0800, Dimitris Dimitropoulos wrote:
> Hi,
>
> I'm trying to inspect RDMA headers and they do not show up on
> wireshark. How can I observe RDMA headers ? Also, any header parser
> available in the code base that I can link to and use to process the
> headers ?

The libpcap which is compiled with RDMA support has ability to catch
traffic for mlx4/mlx5 devices.
https://github.com/the-tcpdump-group/libpcap/pull/585

Thanks

>
>
> Thank you.
>
> Dimitris

RE: RDMA header inspection

[Parav Pandit]

> From: linux-rdma-owner@vger.kernel.org <linux-rdma-
> owner@vger.kernel.org> On Behalf Of Leon Romanovsky
> Sent: Tuesday, February 4, 2020 1:38 AM
> To: Dimitris Dimitropoulos <d.dimitropoulos@imatrex.com>
> Cc: linux-rdma@vger.kernel.org
> Subject: Re: RDMA header inspection
> 
> On Mon, Feb 03, 2020 at 11:30:09AM -0800, Dimitris Dimitropoulos wrote:
> > Hi,
> >
> > I'm trying to inspect RDMA headers and they do not show up on
> > wireshark. How can I observe RDMA headers ? Also, any header parser
> > available in the code base that I can link to and use to process the
> > headers ?
> 
> The libpcap which is compiled with RDMA support has ability to catch traffic for
> mlx4/mlx5 devices.
> https://github.com/the-tcpdump-group/libpcap/pull/585
> 

If you want to consume this feature in simpler and quicker way, you can follow the steps [1] without affecting your OS userspace environment.
I find it useful and quick way to debug issues.

But feel free ignore my suggestion and use your latest or compiled tcpdump with latest libpcap.

[1] https://hub.docker.com/r/mellanox/tcpdump-rdma

Re: RDMA header inspection

[Dimitris Dimitropoulos]

Hi,

That seems to be the simplest way to view the traffic. I just tried it
successfully on a ConnectX-5 card (Mellanox driver OFED-5.0 on a
Centos 7.7 / Kernel 3.10.0).

Thank you.

Dimitris

On Mon, Feb 3, 2020 at 11:53 PM Parav Pandit <parav@mellanox.com> wrote:
>
>
>
> > From: linux-rdma-owner@vger.kernel.org <linux-rdma-
> > owner@vger.kernel.org> On Behalf Of Leon Romanovsky
> > Sent: Tuesday, February 4, 2020 1:38 AM
> > To: Dimitris Dimitropoulos <d.dimitropoulos@imatrex.com>
> > Cc: linux-rdma@vger.kernel.org
> > Subject: Re: RDMA header inspection
> >
> > On Mon, Feb 03, 2020 at 11:30:09AM -0800, Dimitris Dimitropoulos wrote:
> > > Hi,
> > >
> > > I'm trying to inspect RDMA headers and they do not show up on
> > > wireshark. How can I observe RDMA headers ? Also, any header parser
> > > available in the code base that I can link to and use to process the
> > > headers ?
> >
> > The libpcap which is compiled with RDMA support has ability to catch traffic for
> > mlx4/mlx5 devices.
> > https://github.com/the-tcpdump-group/libpcap/pull/585
> >
>
> If you want to consume this feature in simpler and quicker way, you can follow the steps [1] without affecting your OS userspace environment.
> I find it useful and quick way to debug issues.
>
> But feel free ignore my suggestion and use your latest or compiled tcpdump with latest libpcap.
>
> [1] https://hub.docker.com/r/mellanox/tcpdump-rdma