@@ -2,14 +2,15 @@
# Copyright(c) 2022 University of New Hampshire
# Copyright(c) 2023 PANTHEON.tech s.r.o.
-"""Scapy traffic generator.
+"""The Scapy traffic generator.
-Traffic generator used for functional testing, implemented using the Scapy library.
+A traffic generator used for functional testing, implemented with
+`the Scapy library <https://scapy.readthedocs.io/en/latest/>`_.
The traffic generator uses an XML-RPC server to run Scapy on the remote TG node.
-The XML-RPC server runs in an interactive remote SSH session running Python console,
-where we start the server. The communication with the server is facilitated with
-a local server proxy.
+The traffic generator uses the :mod:`xmlrpc.server` module to run an XML-RPC server
+in an interactive remote Python SSH session. The communication with the server is facilitated
+with a local server proxy from the :mod:`xmlrpc.client` module.
"""
import inspect
@@ -69,20 +70,20 @@ def scapy_send_packets_and_capture(
recv_iface: str,
duration: float,
) -> list[bytes]:
- """RPC function to send and capture packets.
+ """The RPC function to send and capture packets.
- The function is meant to be executed on the remote TG node.
+ This function is meant to be executed on the remote TG node via the server proxy.
Args:
xmlrpc_packets: The packets to send. These need to be converted to
- xmlrpc.client.Binary before sending to the remote server.
+ :class:`~xmlrpc.client.Binary` objects before sending to the remote server.
send_iface: The logical name of the egress interface.
recv_iface: The logical name of the ingress interface.
duration: Capture for this amount of time, in seconds.
Returns:
A list of bytes. Each item in the list represents one packet, which needs
- to be converted back upon transfer from the remote node.
+ to be converted back upon transfer from the remote node.
"""
scapy_packets = [scapy.all.Packet(packet.data) for packet in xmlrpc_packets]
sniffer = scapy.all.AsyncSniffer(
@@ -96,19 +97,15 @@ def scapy_send_packets_and_capture(
def scapy_send_packets(xmlrpc_packets: list[xmlrpc.client.Binary], send_iface: str) -> None:
- """RPC function to send packets.
+ """The RPC function to send packets.
- The function is meant to be executed on the remote TG node.
- It doesn't return anything, only sends packets.
+ This function is meant to be executed on the remote TG node via the server proxy.
+ It only sends `xmlrpc_packets`, without capturing them.
Args:
xmlrpc_packets: The packets to send. These need to be converted to
- xmlrpc.client.Binary before sending to the remote server.
+ :class:`~xmlrpc.client.Binary` objects before sending to the remote server.
send_iface: The logical name of the egress interface.
-
- Returns:
- A list of bytes. Each item in the list represents one packet, which needs
- to be converted back upon transfer from the remote node.
"""
scapy_packets = [scapy.all.Packet(packet.data) for packet in xmlrpc_packets]
scapy.all.sendp(scapy_packets, iface=send_iface, realtime=True, verbose=True)
@@ -128,11 +125,19 @@ def scapy_send_packets(xmlrpc_packets: list[xmlrpc.client.Binary], send_iface: s
class QuittableXMLRPCServer(SimpleXMLRPCServer):
- """Basic XML-RPC server that may be extended
- by functions serializable by the marshal module.
+ """Basic XML-RPC server.
+
+ The server may be augmented by functions serializable by the :mod:`marshal` module.
"""
def __init__(self, *args, **kwargs):
+ """Extend the XML-RPC server initialization.
+
+ Args:
+ args: The positional arguments that will be passed to the superclass's constructor.
+ kwargs: The keyword arguments that will be passed to the superclass's constructor.
+ The `allow_none` argument will be set to :data:`True`.
+ """
kwargs["allow_none"] = True
super().__init__(*args, **kwargs)
self.register_introspection_functions()
@@ -140,13 +145,12 @@ def __init__(self, *args, **kwargs):
self.register_function(self.add_rpc_function)
def quit(self) -> None:
+ """Quit the server."""
self._BaseServer__shutdown_request = True
return None
def add_rpc_function(self, name: str, function_bytes: xmlrpc.client.Binary) -> None:
- """Add a function to the server.
-
- This is meant to be executed remotely.
+ """Add a function to the server from the local server proxy.
Args:
name: The name of the function.
@@ -157,6 +161,11 @@ def add_rpc_function(self, name: str, function_bytes: xmlrpc.client.Binary) -> N
self.register_function(function)
def serve_forever(self, poll_interval: float = 0.5) -> None:
+ """Extend the superclass method with an additional print.
+
+ Once executed in the local server proxy, the print gives us a clear string to expect
+ when starting the server. The print means this function was executed on the XML-RPC server.
+ """
print("XMLRPC OK")
super().serve_forever(poll_interval)
@@ -164,19 +173,12 @@ def serve_forever(self, poll_interval: float = 0.5) -> None:
class ScapyTrafficGenerator(CapturingTrafficGenerator):
"""Provides access to scapy functions via an RPC interface.
- The traffic generator first starts an XML-RPC on the remote TG node.
- Then it populates the server with functions which use the Scapy library
- to send/receive traffic.
-
- Any packets sent to the remote server are first converted to bytes.
- They are received as xmlrpc.client.Binary objects on the server side.
- When the server sends the packets back, they are also received as
- xmlrpc.client.Binary object on the client side, are converted back to Scapy
- packets and only then returned from the methods.
+ This class extends the base with remote execution of scapy functions.
- Arguments:
- tg_node: The node where the traffic generator resides.
- config: The user configuration of the traffic generator.
+ Any packets sent to the remote server are first converted to bytes. They are received as
+ :class:`~xmlrpc.client.Binary` objects on the server side. When the server sends the packets
+ back, they are also received as :class:`~xmlrpc.client.Binary` objects on the client side, are
+ converted back to :class:`~scapy.packet.Packet` objects and only then returned from the methods.
Attributes:
session: The exclusive interactive remote session created by the Scapy
@@ -190,6 +192,22 @@ class ScapyTrafficGenerator(CapturingTrafficGenerator):
_config: ScapyTrafficGeneratorConfig
def __init__(self, tg_node: Node, config: ScapyTrafficGeneratorConfig):
+ """Extend the constructor with Scapy TG specifics.
+
+ The traffic generator first starts an XML-RPC on the remote `tg_node`.
+ Then it populates the server with functions which use the Scapy library
+ to send/receive traffic:
+
+ * :func:`scapy_send_packets_and_capture`
+ * :func:`scapy_send_packets`
+
+ To enable verbose logging from the xmlrpc client, use the :option:`--verbose`
+ command line argument or the :envvar:`DTS_VERBOSE` environment variable.
+
+ Args:
+ tg_node: The node where the traffic generator resides.
+ config: The traffic generator's test run configuration.
+ """
super().__init__(tg_node, config)
assert (
@@ -231,10 +249,8 @@ def _start_xmlrpc_server_in_remote_python(self, listen_port: int) -> None:
# or class, so strip all lines containing only whitespace
src = "\n".join([line for line in src.splitlines() if not line.isspace() and line != ""])
- spacing = "\n" * 4
-
# execute it in the python terminal
- self.session.send_command(spacing + src + spacing)
+ self.session.send_command(src + "\n")
self.session.send_command(
f"server = QuittableXMLRPCServer(('0.0.0.0', {listen_port}));server.serve_forever()",
"XMLRPC OK",
@@ -267,6 +283,7 @@ def _send_packets_and_capture(
return scapy_packets
def close(self) -> None:
+ """Close the traffic generator."""
try:
self.rpc_server_proxy.quit()
except ConnectionRefusedError: