3d36f19a0f
Rather than only using time-based method of periodically checking whether the pcap file appeared, first check that the packet generator has stopped. To make this change fail-safe, have a 5-minute timeout on this activity, just in case the things go terribly wrong. Type: test Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com> Change-Id: Id16b2802b2de8a4cafb5d9f0a8c9ba62ec89dc32
518 lines
20 KiB
Python
Executable File
518 lines
20 KiB
Python
Executable File
import os
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import time
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import socket
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import struct
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from traceback import format_exc, format_stack
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import scapy.compat
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from scapy.utils import wrpcap, rdpcap, PcapReader
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from scapy.plist import PacketList
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from vpp_interface import VppInterface
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from scapy.layers.l2 import Ether, ARP
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from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
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ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
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IPv6ExtHdrHopByHop
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from util import ppp, ppc
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from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
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from scapy.utils import inet_pton, inet_ntop
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class CaptureTimeoutError(Exception):
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""" Exception raised if capture or packet doesn't appear within timeout """
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pass
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def is_ipv6_misc(p):
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""" Is packet one of uninteresting IPv6 broadcasts? """
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if p.haslayer(ICMPv6ND_RA):
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if in6_ismaddr(p[IPv6].dst):
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return True
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if p.haslayer(IPv6ExtHdrHopByHop):
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for o in p[IPv6ExtHdrHopByHop].options:
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if isinstance(o, RouterAlert):
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return True
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return False
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class VppPGInterface(VppInterface):
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"""
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VPP packet-generator interface
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"""
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@property
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def pg_index(self):
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"""packet-generator interface index assigned by VPP"""
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return self._pg_index
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@property
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def gso_enabled(self):
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"""gso enabled on packet-generator interface"""
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if self._gso_enabled == 0:
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return "gso-disabled"
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return "gso-enabled"
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@property
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def gso_size(self):
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"""gso size on packet-generator interface"""
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return self._gso_size
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@property
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def out_path(self):
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"""pcap file path - captured packets"""
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return self._out_path
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@property
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def in_path(self):
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""" pcap file path - injected packets"""
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return self._in_path
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@property
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def capture_cli(self):
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"""CLI string to start capture on this interface"""
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return self._capture_cli
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@property
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def cap_name(self):
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"""capture name for this interface"""
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return self._cap_name
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@property
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def input_cli(self):
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"""CLI string to load the injected packets"""
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if self._nb_replays is not None:
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return "%s limit %d" % (self._input_cli, self._nb_replays)
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if self._worker is not None:
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return "%s worker %d" % (self._input_cli, self._worker)
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return self._input_cli
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@property
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def in_history_counter(self):
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"""Self-incrementing counter used when renaming old pcap files"""
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v = self._in_history_counter
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self._in_history_counter += 1
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return v
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@property
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def out_history_counter(self):
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"""Self-incrementing counter used when renaming old pcap files"""
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v = self._out_history_counter
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self._out_history_counter += 1
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return v
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def __init__(self, test, pg_index, gso, gso_size):
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""" Create VPP packet-generator interface """
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super(VppPGInterface, self).__init__(test)
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r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
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self.set_sw_if_index(r.sw_if_index)
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self._in_history_counter = 0
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self._out_history_counter = 0
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self._out_assert_counter = 0
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self._pg_index = pg_index
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self._gso_enabled = gso
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self._gso_size = gso_size
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self._out_file = "pg%u_out.pcap" % self.pg_index
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self._out_path = self.test.tempdir + "/" + self._out_file
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self._in_file = "pg%u_in.pcap" % self.pg_index
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self._in_path = self.test.tempdir + "/" + self._in_file
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self._capture_cli = "packet-generator capture pg%u pcap %s" % (
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self.pg_index, self.out_path)
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self._cap_name = "pcap%u-sw_if_index-%s" % (
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self.pg_index, self.sw_if_index)
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self._input_cli = \
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"packet-generator new pcap %s source pg%u name %s" % (
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self.in_path, self.pg_index, self.cap_name)
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self._nb_replays = None
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def _rename_previous_capture_file(self, path, counter, file):
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# if a file from a previous capture exists, rename it.
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try:
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if os.path.isfile(path):
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name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
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(self.test.tempdir,
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time.time(),
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self.name,
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counter,
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file)
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self.test.logger.debug("Renaming %s->%s" %
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(path, name))
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os.rename(path, name)
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except OSError:
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self.test.logger.debug("OSError: Could not rename %s %s" %
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(path, file))
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def enable_capture(self):
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""" Enable capture on this packet-generator interface
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of at most n packets.
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If n < 0, this is no limit
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"""
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# disable the capture to flush the capture
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self.disable_capture()
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self._rename_previous_capture_file(self.out_path,
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self.out_history_counter,
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self._out_file)
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# FIXME this should be an API, but no such exists atm
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self.test.vapi.cli(self.capture_cli)
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self._pcap_reader = None
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def disable_capture(self):
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self.test.vapi.cli("%s disable" % self.capture_cli)
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def add_stream(self, pkts, nb_replays=None, worker=None):
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"""
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Add a stream of packets to this packet-generator
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:param pkts: iterable packets
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"""
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self._worker = worker
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self._nb_replays = nb_replays
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self._rename_previous_capture_file(self.in_path,
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self.in_history_counter,
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self._in_file)
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wrpcap(self.in_path, pkts)
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self.test.register_capture(self.cap_name)
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# FIXME this should be an API, but no such exists atm
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self.test.vapi.cli(self.input_cli)
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def generate_debug_aid(self, kind):
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""" Create a hardlink to the out file with a counter and a file
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containing stack trace to ease debugging in case of multiple capture
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files present. """
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self.test.logger.debug("Generating debug aid for %s on %s" %
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(kind, self._name))
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link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
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(self.test.tempdir, self._name,
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self._out_assert_counter, kind, suffix)
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for suffix in ["pcap", "stack"]
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]
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os.link(self.out_path, link_path)
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with open(stack_path, "w") as f:
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f.writelines(format_stack())
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self._out_assert_counter += 1
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def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
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""" Helper method to get capture and filter it """
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try:
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if not self.wait_for_capture_file(timeout):
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return None
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output = rdpcap(self.out_path)
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self.test.logger.debug("Capture has %s packets" % len(output.res))
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except:
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self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
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(self.out_path, format_exc()))
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return None
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before = len(output.res)
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if filter_out_fn:
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output.res = [p for p in output.res if not filter_out_fn(p)]
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removed = before - len(output.res)
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if removed:
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self.test.logger.debug(
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"Filtered out %s packets from capture (returning %s)" %
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(removed, len(output.res)))
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return output
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def get_capture(self, expected_count=None, remark=None, timeout=1,
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filter_out_fn=is_ipv6_misc):
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""" Get captured packets
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:param expected_count: expected number of packets to capture, if None,
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then self.test.packet_count_for_dst_pg_idx is
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used to lookup the expected count
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:param remark: remark printed into debug logs
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:param timeout: how long to wait for packets
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:param filter_out_fn: filter applied to each packet, packets for which
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the filter returns True are removed from capture
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:returns: iterable packets
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"""
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remaining_time = timeout
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capture = None
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name = self.name if remark is None else "%s (%s)" % (self.name, remark)
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based_on = "based on provided argument"
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if expected_count is None:
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expected_count = \
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self.test.get_packet_count_for_if_idx(self.sw_if_index)
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based_on = "based on stored packet_infos"
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if expected_count == 0:
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raise Exception(
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"Internal error, expected packet count for %s is 0!" %
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name)
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self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
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expected_count, based_on, name))
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while remaining_time > 0:
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before = time.time()
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capture = self._get_capture(remaining_time, filter_out_fn)
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elapsed_time = time.time() - before
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if capture:
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if len(capture.res) == expected_count:
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# bingo, got the packets we expected
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return capture
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elif len(capture.res) > expected_count:
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self.test.logger.error(
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ppc("Unexpected packets captured:", capture))
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break
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else:
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self.test.logger.debug("Partial capture containing %s "
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"packets doesn't match expected "
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"count %s (yet?)" %
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(len(capture.res), expected_count))
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elif expected_count == 0:
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# bingo, got None as we expected - return empty capture
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return PacketList()
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remaining_time -= elapsed_time
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if capture:
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self.generate_debug_aid("count-mismatch")
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raise Exception("Captured packets mismatch, captured %s packets, "
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"expected %s packets on %s" %
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(len(capture.res), expected_count, name))
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else:
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raise Exception("No packets captured on %s" % name)
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def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
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""" Assert that nothing unfiltered was captured on interface
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:param remark: remark printed into debug logs
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:param filter_out_fn: filter applied to each packet, packets for which
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the filter returns True are removed from capture
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"""
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if os.path.isfile(self.out_path):
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try:
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capture = self.get_capture(
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0, remark=remark, filter_out_fn=filter_out_fn)
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if not capture or len(capture.res) == 0:
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# junk filtered out, we're good
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return
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except:
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pass
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self.generate_debug_aid("empty-assert")
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if remark:
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raise AssertionError(
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"Non-empty capture file present for interface %s (%s)" %
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(self.name, remark))
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else:
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raise AssertionError("Capture file present for interface %s" %
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self.name)
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def wait_for_pg_stop(self):
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# wait till packet-generator is stopped
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# "show packet-generator" while it is still running gives this:
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# Name Enabled Count Parameters
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# pcap0-sw_if_inde Yes 64 limit 64, ...
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#
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# also have a 5-minute timeout just in case things go terribly wrong...
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deadline = time.time() + 300
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while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
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self._test.sleep(0.01) # yield
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if time.time() > deadline:
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self.test.logger.debug("Timeout waiting for pg to stop")
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break
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def wait_for_capture_file(self, timeout=1):
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"""
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Wait until pcap capture file appears
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:param timeout: How long to wait for the packet (default 1s)
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:returns: True/False if the file is present or appears within timeout
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"""
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self.wait_for_pg_stop()
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deadline = time.time() + timeout
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if not os.path.isfile(self.out_path):
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self.test.logger.debug("Waiting for capture file %s to appear, "
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"timeout is %ss" % (self.out_path, timeout))
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else:
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self.test.logger.debug("Capture file %s already exists" %
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self.out_path)
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return True
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while time.time() < deadline:
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if os.path.isfile(self.out_path):
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break
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self._test.sleep(0) # yield
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if os.path.isfile(self.out_path):
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self.test.logger.debug("Capture file appeared after %fs" %
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(time.time() - (deadline - timeout)))
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else:
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self.test.logger.debug("Timeout - capture file still nowhere")
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return False
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return True
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def verify_enough_packet_data_in_pcap(self):
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"""
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Check if enough data is available in file handled by internal pcap
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reader so that a whole packet can be read.
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:returns: True if enough data present, else False
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"""
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orig_pos = self._pcap_reader.f.tell() # save file position
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enough_data = False
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# read packet header from pcap
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packet_header_size = 16
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caplen = None
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end_pos = None
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hdr = self._pcap_reader.f.read(packet_header_size)
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if len(hdr) == packet_header_size:
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# parse the capture length - caplen
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sec, usec, caplen, wirelen = struct.unpack(
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self._pcap_reader.endian + "IIII", hdr)
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self._pcap_reader.f.seek(0, 2) # seek to end of file
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end_pos = self._pcap_reader.f.tell() # get position at end
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if end_pos >= orig_pos + len(hdr) + caplen:
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enough_data = True # yay, we have enough data
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self._pcap_reader.f.seek(orig_pos, 0) # restore original position
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return enough_data
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def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
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"""
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Wait for next packet captured with a timeout
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:param timeout: How long to wait for the packet
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:returns: Captured packet if no packet arrived within timeout
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:raises Exception: if no packet arrives within timeout
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"""
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deadline = time.time() + timeout
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if self._pcap_reader is None:
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if not self.wait_for_capture_file(timeout):
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raise CaptureTimeoutError("Capture file %s did not appear "
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"within timeout" % self.out_path)
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while time.time() < deadline:
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try:
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self._pcap_reader = PcapReader(self.out_path)
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break
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except:
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self.test.logger.debug(
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"Exception in scapy.PcapReader(%s): %s" %
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(self.out_path, format_exc()))
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if not self._pcap_reader:
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raise CaptureTimeoutError("Capture file %s did not appear within "
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"timeout" % self.out_path)
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poll = False
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if timeout > 0:
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self.test.logger.debug("Waiting for packet")
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else:
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poll = True
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self.test.logger.debug("Polling for packet")
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while time.time() < deadline or poll:
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if not self.verify_enough_packet_data_in_pcap():
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self._test.sleep(0) # yield
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poll = False
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continue
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p = self._pcap_reader.recv()
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if p is not None:
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if filter_out_fn is not None and filter_out_fn(p):
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self.test.logger.debug(
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"Packet received after %ss was filtered out" %
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(time.time() - (deadline - timeout)))
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else:
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self.test.logger.debug(
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"Packet received after %fs" %
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(time.time() - (deadline - timeout)))
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return p
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self._test.sleep(0) # yield
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poll = False
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self.test.logger.debug("Timeout - no packets received")
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raise CaptureTimeoutError("Packet didn't arrive within timeout")
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def create_arp_req(self):
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"""Create ARP request applicable for this interface"""
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return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
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ARP(op=ARP.who_has, pdst=self.local_ip4,
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psrc=self.remote_ip4, hwsrc=self.remote_mac))
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def create_ndp_req(self):
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"""Create NDP - NS applicable for this interface"""
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nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
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d = inet_ntop(socket.AF_INET6, nsma)
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return (Ether(dst=in6_getnsmac(nsma)) /
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IPv6(dst=d, src=self.remote_ip6) /
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ICMPv6ND_NS(tgt=self.local_ip6) /
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ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
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def resolve_arp(self, pg_interface=None):
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"""Resolve ARP using provided packet-generator interface
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:param pg_interface: interface used to resolve, if None then this
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interface is used
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"""
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if pg_interface is None:
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pg_interface = self
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self.test.logger.info("Sending ARP request for %s on port %s" %
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(self.local_ip4, pg_interface.name))
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arp_req = self.create_arp_req()
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pg_interface.add_stream(arp_req)
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pg_interface.enable_capture()
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self.test.pg_start()
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self.test.logger.info(self.test.vapi.cli("show trace"))
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try:
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captured_packet = pg_interface.wait_for_packet(1)
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except:
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self.test.logger.info("No ARP received on port %s" %
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pg_interface.name)
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return
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arp_reply = captured_packet.copy() # keep original for exception
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try:
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if arp_reply[ARP].op == ARP.is_at:
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self.test.logger.info("VPP %s MAC address is %s " %
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(self.name, arp_reply[ARP].hwsrc))
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self._local_mac = arp_reply[ARP].hwsrc
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else:
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self.test.logger.info("No ARP received on port %s" %
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pg_interface.name)
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except:
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self.test.logger.error(
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ppp("Unexpected response to ARP request:", captured_packet))
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raise
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def resolve_ndp(self, pg_interface=None, timeout=1):
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"""Resolve NDP using provided packet-generator interface
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:param pg_interface: interface used to resolve, if None then this
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interface is used
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:param timeout: how long to wait for response before giving up
|
|
|
|
"""
|
|
if pg_interface is None:
|
|
pg_interface = self
|
|
self.test.logger.info("Sending NDP request for %s on port %s" %
|
|
(self.local_ip6, pg_interface.name))
|
|
ndp_req = self.create_ndp_req()
|
|
pg_interface.add_stream(ndp_req)
|
|
pg_interface.enable_capture()
|
|
self.test.pg_start()
|
|
now = time.time()
|
|
deadline = now + timeout
|
|
# Enabling IPv6 on an interface can generate more than the
|
|
# ND reply we are looking for (namely MLD). So loop through
|
|
# the replies to look for want we want.
|
|
while now < deadline:
|
|
try:
|
|
captured_packet = pg_interface.wait_for_packet(
|
|
deadline - now, filter_out_fn=None)
|
|
except:
|
|
self.test.logger.error(
|
|
"Timeout while waiting for NDP response")
|
|
raise
|
|
ndp_reply = captured_packet.copy() # keep original for exception
|
|
try:
|
|
ndp_na = ndp_reply[ICMPv6ND_NA]
|
|
opt = ndp_na[ICMPv6NDOptDstLLAddr]
|
|
self.test.logger.info("VPP %s MAC address is %s " %
|
|
(self.name, opt.lladdr))
|
|
self._local_mac = opt.lladdr
|
|
self.test.logger.debug(self.test.vapi.cli("show trace"))
|
|
# we now have the MAC we've been after
|
|
return
|
|
except:
|
|
self.test.logger.info(
|
|
ppp("Unexpected response to NDP request:",
|
|
captured_packet))
|
|
now = time.time()
|
|
|
|
self.test.logger.debug(self.test.vapi.cli("show trace"))
|
|
raise Exception("Timeout while waiting for NDP response")
|