Rawnetworkinterface stream

[JoshuaWatt]

Description

Adds support for live streaming packets from a RawNetworkInterfaceDriver. This can be useful for writing tests that parse packets in real time looking for a specific pattern, for example:

import dpkt
    
drv = target.get_driver("RawNetworkInterfaceDriver")
    
with drv.record("-", timeout=60) as p:
    pcap = dpkt.pcap.Reader(p.stdout)
    for timestamp, buf in pcap:
        eth = dpkt.ethernet.Ethernet(buf)

        if _some_criteria_:
            break
    else:
        assert False, "Packet not found!"

Checklist

• [ ] Documentation for the feature
• [ ] Tests for the feature

• [ ] The arguments and description in doc/configuration.rst have been updated

• [ ] Add a section on how to use the feature to doc/usage.rst

• [ ] Add a section on how to use the feature to doc/development.rst

• [x] PR has been tested

• [ ] Man pages have been regenerated

[JoshuaWatt]

Of note, we've had a local driver that was very similar to RawNetworkInterfaceDriver for some time that was used to stream packets; the intention of this patch is to bring it in line with the functionality in that driver so we can eliminate it. For posterity, here is our driver:

import attr
import subprocess
import dpkt
from contextlib import contextmanager

from labgrid import target_factory
from labgrid.driver import Driver


@target_factory.reg_driver
@attr.s(eq=False)
class InterfaceCaptureDriver(Driver):
    """Driver to obtain tcpdump output from device's network"""

    bindings = {
        "iface": {"RemoteNetworkInterface", "USBNetworkInterface", "NetworkInterface"},
    }

    @contextmanager
    def live_capture(self, timeout=None):
        """
        Perform live capture of traffic from device's network.

        :param int timeout: When specified, performs capture for ``timeout`` seconds. \
            Defaults to `None`.

        :yields: A `dpkt.pcap.Reader` object of the captured network traffic
        """
        extra = getattr(self.iface, "extra", {})
        command = ["sudo", "tcpdump", "-i", self.iface.ifname, "-U", "-s0", "-w", "-"]

        if timeout is not None:
            command.extend(["-G", str(timeout), "-W", "1"])

        if "proxy_required" in extra:
            command = ["ssh", extra["proxy"], "--"] + command

        with subprocess.Popen(command, stdout=subprocess.PIPE) as p:
            yield dpkt.pcap.Reader(p.stdout)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 14.28571% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 62.7%. Comparing base (722838b) to head (d68686a). Report is 9 commits behind head on master.

:exclamation: Current head d68686a differs from pull request most recent head fdeb30b. Consider uploading reports for the commit fdeb30b to get more accurate results

Files	Patch %	Lines
labgrid/driver/rawnetworkinterfacedriver.py	14.2%	12 Missing :warning:

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #1320     +/-   ##
========================================
+ Coverage    62.2%   62.7%   +0.5%     
========================================
  Files         164     163      -1     
  Lines       12191   12008    -183     
========================================
- Hits         7584    7534     -50     
+ Misses       4607    4474    -133     

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[Bastian-Krause]

@JoshuaWatt I'm interested in using the changes in this PR in our network tests. Could you have a look at the review comments? If you don't have the time to integrate the changes, I'd be willing to take this over.

[JoshuaWatt]

@JoshuaWatt I'm interested in using the changes in this PR in our network tests. Could you have a look at the review comments? If you don't have the time to integrate the changes, I'd be willing to take this over.

I'll take a look this week. I was AFK for EOSS

[JoshuaWatt]

Any update on this?

[JoshuaWatt]

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