Re: [PATCH v2 2/3] Packet sniffer core framework

Daniel Borkmann
2015-02-18T15:42:06Z

On 02/17/2015 03:03 PM, Stathis Voukelatos wrote:
> The framework registers each backend sniffer channel as a netdev,
> which can be accessed from user space through a raw packet socket.
> Packets received from user space are treated as a command string
> configuration. Each match event from the backend driver will
> generate a packet with the matching bytes plus an optional
> timestamp, if configured by the command string.
>
> Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
> ---
> MAINTAINERS | 6 +
> drivers/net/Kconfig | 2 +
> drivers/net/Makefile | 2 +
> drivers/net/pkt-sniffer/Kconfig | 8 +
> drivers/net/pkt-sniffer/Makefile | 3 +
> drivers/net/pkt-sniffer/core/module.c | 37 +++++
> drivers/net/pkt-sniffer/core/netdev.c | 254 ++++++++++++++++++++++++++++++++
> drivers/net/pkt-sniffer/core/snf_core.h | 60 ++++++++
> include/uapi/linux/pkt_sniffer.h | 33 +++++
> 9 files changed, 405 insertions(+)
> create mode 100644 drivers/net/pkt-sniffer/Kconfig
> create mode 100644 drivers/net/pkt-sniffer/Makefile
> create mode 100644 drivers/net/pkt-sniffer/core/module.c
> create mode 100644 drivers/net/pkt-sniffer/core/netdev.c
> create mode 100644 drivers/net/pkt-sniffer/core/snf_core.h
> create mode 100644 include/uapi/linux/pkt_sniffer.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index aaa039d..7d882de 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5754,6 +5754,12 @@ M: Sasha Levin <sasha.levin@oracle.com>
> S: Maintained
> F: tools/lib/lockdep/
>
> +LINN PACKET SNIFFER DRIVER
> +M: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
> +S: Maintained
> +F: drivers/net/pkt-sniffer/
> +F: Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt

This whole framework really looks like only tailored to your specific
driver, I have no idea who else should reuse that?! So, I don't think
putting this under drivers/net/pkt-sniffer/ is a good idea.

Also it looks slightly confusing as if I understand you correctly, your
module's purpose is to pass down some "packet pattern" to the hardware
and match that in order to get a precise timestamp in return?

Might perhaps be better to have everything vendor-specific under something
like drivers/net/ethernet/linn/ and have the framework squashed into the
driver itself (if parts cannot be generalized in net/packet/).

It would be good if you can also avoid the extra uapi export. Perhaps
it's possible to reuse at least some of the existing timestamping
infrastructure?