On Wed, Jan 3, 2024 at 11:33 PM <jspew...@iol.unh.edu> wrote:
>
> From: Jeremy Spewock <jspew...@iol.unh.edu>
>
> Added the options to filter out LLDP and ARP packets when
> sniffing for packets with scapy. This was done using BPF filters to
> ensure that the noise these packets provide does not interfere with test
> cases.
>
> Signed-off-by: Jeremy Spewock <jspew...@iol.unh.edu>
> ---
> dts/framework/test_suite.py | 15 +++++++++--
> dts/framework/testbed_model/tg_node.py | 14 ++++++++--
> .../traffic_generator/__init__.py | 7 ++++-
> .../capturing_traffic_generator.py | 22 ++++++++++++++-
> .../testbed_model/traffic_generator/scapy.py | 27 +++++++++++++++++++
> 5 files changed, 79 insertions(+), 6 deletions(-)
>
<snip>
> diff --git
> a/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
>
> b/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
> index 0246590333..c1c9facedd 100644
> ---
> a/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
> +++
> b/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
<snip>
> @@ -26,6 +27,19 @@ def _get_default_capture_name() -> str:
> return str(uuid.uuid4())
>
>
> +@dataclass(slots=True)
This should also be frozen. If we need a different filter, it's better
to create a new object I think.
> +class PacketFilteringConfig:
> + """The supported filtering options for
> :class:`CapturingTrafficGenerator`.
> +
> + Attributes:
> + no_lldp: If :data:`True`, LLDP packets will be filtered out when
> capturing.
> + no_arp: If :data:`True`, ARP packets will be filtered out when
> capturing.
> + """
> +
> + no_lldp: bool = True
> + no_arp: bool = True
> +
> +
> class CapturingTrafficGenerator(TrafficGenerator):
> """Capture packets after sending traffic.
>
<snip>
> diff --git a/dts/framework/testbed_model/traffic_generator/scapy.py
> b/dts/framework/testbed_model/traffic_generator/scapy.py
> index 5b60f66237..505de0be94 100644
> --- a/dts/framework/testbed_model/traffic_generator/scapy.py
> +++ b/dts/framework/testbed_model/traffic_generator/scapy.py
<snip>
> @@ -260,11 +263,34 @@ def _send_packets(self, packets: list[Packet], port:
> Port) -> None:
> packets = [packet.build() for packet in packets]
> self.rpc_server_proxy.scapy_send_packets(packets, port.logical_name)
>
> + def _create_packet_filter(self, filter_config: PacketFilteringConfig) ->
> str:
> + """Combines filter settings from `filter_config` into a BPF that
> scapy can use.
> +
> + Scapy allows for the use of Berkeley Packet Filters (BPFs) to filter
> what packets are
> + collected based on various attributes of the packet.
> +
> + Args:
> + filter_config: Config class that specifies which filters should
> be applied.
> +
> + Returns:
> + A string representing the combination of BPF filters to be
> passed to scapy. For
> + example:
> +
> + "ether[12:2] != 0x88cc && ether[12:2] != 0x0806"
> + """
> + bpf_filter: list[str] = []
The type hint here is not needed, so let's make this consistent with
the rest of the code - we don't specify local type hints if they're
not necessary.
> + if filter_config.no_arp:
> + bpf_filter.append("ether[12:2] != 0x0806")
> + if filter_config.no_lldp:
> + bpf_filter.append("ether[12:2] != 0x88cc")
> + return " && ".join(bpf_filter)
> +
> def _send_packets_and_capture(
> self,
> packets: list[Packet],
> send_port: Port,
> receive_port: Port,
> + filter_config: PacketFilteringConfig,
> duration: float,
> capture_name: str = _get_default_capture_name(),
> ) -> list[Packet]:
