Reviewed-by: Juraj Linkeš <juraj.lin...@pantheon.tech>
On Mon, Dec 18, 2023 at 7:13 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 | 14 ++++++++--
> .../capturing_traffic_generator.py | 22 ++++++++++++++-
> dts/framework/testbed_model/scapy.py | 28 ++++++++++++++++++-
> dts/framework/testbed_model/tg_node.py | 12 ++++++--
> 4 files changed, 70 insertions(+), 6 deletions(-)
>
> diff --git a/dts/framework/test_suite.py b/dts/framework/test_suite.py
> index 4a7907ec33..6dfa570041 100644
> --- a/dts/framework/test_suite.py
> +++ b/dts/framework/test_suite.py
> @@ -27,6 +27,7 @@
> from .settings import SETTINGS
> from .test_result import BuildTargetResult, Result, TestCaseResult,
> TestSuiteResult
> from .testbed_model import SutNode, TGNode
> +from .testbed_model.capturing_traffic_generator import PacketFilteringConfig
> from .testbed_model.hw.port import Port, PortLink
> from .utils import get_packet_summaries
>
> @@ -149,7 +150,12 @@ def configure_testbed_ipv4(self, restore: bool = False)
> -> None:
> def _configure_ipv4_forwarding(self, enable: bool) -> None:
> self.sut_node.configure_ipv4_forwarding(enable)
>
> - def send_packet_and_capture(self, packet: Packet, duration: float = 1)
> -> list[Packet]:
> + def send_packet_and_capture(
> + self,
> + packet: Packet,
> + filter_config: PacketFilteringConfig = PacketFilteringConfig(),
> + duration: float = 1,
> + ) -> list[Packet]:
> """
> Send a packet through the appropriate interface and
> receive on the appropriate interface.
> @@ -158,7 +164,11 @@ def send_packet_and_capture(self, packet: Packet,
> duration: float = 1) -> list[P
> """
> packet = self._adjust_addresses(packet)
> return self.tg_node.send_packet_and_capture(
> - packet, self._tg_port_egress, self._tg_port_ingress, duration
> + packet,
> + self._tg_port_egress,
> + self._tg_port_ingress,
> + filter_config,
> + duration,
> )
>
> def get_expected_packet(self, packet: Packet) -> Packet:
> diff --git a/dts/framework/testbed_model/capturing_traffic_generator.py
> b/dts/framework/testbed_model/capturing_traffic_generator.py
> index e6512061d7..c40b030fe4 100644
> --- a/dts/framework/testbed_model/capturing_traffic_generator.py
> +++ b/dts/framework/testbed_model/capturing_traffic_generator.py
> @@ -11,6 +11,7 @@
>
> import uuid
> from abc import abstractmethod
> +from dataclasses import dataclass
>
> import scapy.utils # type: ignore[import]
> from scapy.packet import Packet # type: ignore[import]
> @@ -29,6 +30,19 @@ def _get_default_capture_name() -> str:
> return str(uuid.uuid4())
>
>
> +@dataclass(slots=True)
> +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.
>
> @@ -51,6 +65,7 @@ def send_packet_and_capture(
> packet: Packet,
> send_port: Port,
> receive_port: Port,
> + filter_config: PacketFilteringConfig,
> duration: float,
> capture_name: str = _get_default_capture_name(),
> ) -> list[Packet]:
> @@ -64,6 +79,7 @@ def send_packet_and_capture(
> packet: The packet to send.
> send_port: The egress port on the TG node.
> receive_port: The ingress port in the TG node.
> + filter_config: Filters to apply when capturing packets.
> duration: Capture traffic for this amount of time after sending
> the packet.
> capture_name: The name of the .pcap file where to store the
> capture.
>
> @@ -71,7 +87,7 @@ def send_packet_and_capture(
> A list of received packets. May be empty if no packets are
> captured.
> """
> return self.send_packets_and_capture(
> - [packet], send_port, receive_port, duration, capture_name
> + [packet], send_port, receive_port, filter_config, duration,
> capture_name
> )
>
> def send_packets_and_capture(
> @@ -79,6 +95,7 @@ def send_packets_and_capture(
> packets: list[Packet],
> send_port: Port,
> receive_port: Port,
> + filter_config: PacketFilteringConfig,
> duration: float,
> capture_name: str = _get_default_capture_name(),
> ) -> list[Packet]:
> @@ -92,6 +109,7 @@ def send_packets_and_capture(
> packets: The packets to send.
> send_port: The egress port on the TG node.
> receive_port: The ingress port in the TG node.
> + filter_config: Filters to apply when capturing packets.
> duration: Capture traffic for this amount of time after sending
> the packets.
> capture_name: The name of the .pcap file where to store the
> capture.
>
> @@ -106,6 +124,7 @@ def send_packets_and_capture(
> packets,
> send_port,
> receive_port,
> + filter_config,
> duration,
> )
>
> @@ -119,6 +138,7 @@ def _send_packets_and_capture(
> packets: list[Packet],
> send_port: Port,
> receive_port: Port,
> + filter_config: PacketFilteringConfig,
> duration: float,
> ) -> list[Packet]:
> """
> diff --git a/dts/framework/testbed_model/scapy.py
> b/dts/framework/testbed_model/scapy.py
> index 9083e92b3d..94b0af7c6f 100644
> --- a/dts/framework/testbed_model/scapy.py
> +++ b/dts/framework/testbed_model/scapy.py
> @@ -30,6 +30,7 @@
>
> from .capturing_traffic_generator import (
> CapturingTrafficGenerator,
> + PacketFilteringConfig,
> _get_default_capture_name,
> )
> from .hw.port import Port
> @@ -69,6 +70,7 @@ def scapy_send_packets_and_capture(
> send_iface: str,
> recv_iface: str,
> duration: float,
> + sniff_filter: str,
> ) -> list[bytes]:
> """RPC function to send and capture packets.
>
> @@ -90,6 +92,7 @@ def scapy_send_packets_and_capture(
> iface=recv_iface,
> store=True,
> started_callback=lambda *args: scapy.all.sendp(scapy_packets,
> iface=send_iface),
> + filter=sniff_filter,
> )
> sniffer.start()
> time.sleep(duration)
> @@ -249,16 +252,38 @@ 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] = []
> + 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]:
> binary_packets = [packet.build() for packet in packets]
> -
> xmlrpc_packets: list[
> xmlrpc.client.Binary
> ] = self.rpc_server_proxy.scapy_send_packets_and_capture(
> @@ -266,6 +291,7 @@ def _send_packets_and_capture(
> send_port.logical_name,
> receive_port.logical_name,
> duration,
> + self._create_packet_filter(filter_config),
> ) # type: ignore[assignment]
>
> scapy_packets = [Ether(packet.data) for packet in xmlrpc_packets]
> diff --git a/dts/framework/testbed_model/tg_node.py
> b/dts/framework/testbed_model/tg_node.py
> index 79a55663b5..475dc2968d 100644
> --- a/dts/framework/testbed_model/tg_node.py
> +++ b/dts/framework/testbed_model/tg_node.py
> @@ -23,7 +23,10 @@
> )
> from framework.exception import ConfigurationError
>
> -from .capturing_traffic_generator import CapturingTrafficGenerator
> +from .capturing_traffic_generator import (
> + CapturingTrafficGenerator,
> + PacketFilteringConfig,
> +)
> from .hw.port import Port
> from .node import Node
>
> @@ -53,6 +56,7 @@ def send_packet_and_capture(
> packet: Packet,
> send_port: Port,
> receive_port: Port,
> + filter_config: PacketFilteringConfig = PacketFilteringConfig(),
> duration: float = 1,
> ) -> list[Packet]:
> """Send a packet, return received traffic.
> @@ -71,7 +75,11 @@ def send_packet_and_capture(
> A list of received packets. May be empty if no packets are
> captured.
> """
> return self.traffic_generator.send_packet_and_capture(
> - packet, send_port, receive_port, duration
> + packet,
> + send_port,
> + receive_port,
> + filter_config,
> + duration,
> )
>
> def close(self) -> None:
> --
> 2.43.0
>
