/*
* Copyright (c) 2015 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* init.c: mechanism for functions to be called at init/exit.
*
* Copyright (c) 2008 Eliot Dresselhaus
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, import os
import time
import socket
import struct
from traceback import format_exc, format_stack
import scapy.compat
from scapy.utils import wrpcap, rdpcap, PcapReader
from scapy.plist import PacketList
from vpp_interface import VppInterface
from scapy.layers.l2 import Ether, ARP
from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
IPv6ExtHdrHopByHop
from util import ppp, ppc
from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
from scapy.utils import inet_pton, inet_ntop
class CaptureTimeoutError(Exception):
""" Exception raised if capture or packet doesn't appear within timeout """
pass
def is_ipv6_misc(p):
""" Is packet one of uninteresting IPv6 broadcasts? """
if p.haslayer(ICMPv6ND_RA):
if in6_ismaddr(p[IPv6].dst):
return True
if p.haslayer(IPv6ExtHdrHopByHop):
for o in p[IPv6ExtHdrHopByHop].options:
if isinstance(o, RouterAlert):
return True
return False
class VppPGInterface(VppInterface):
"""
VPP packet-generator interface
"""
@property
def pg_index(self):
"""packet-generator interface index assigned by VPP"""
return self._pg_index
@property
def gso_enabled(self):
"""gso enabled on packet-generator interface"""
if self._gso_enabled == 0:
return "gso-disabled"
return "gso-enabled"
@property
def gso_size(self):
"""gso size on packet-generator interface"""
return self._gso_size
@property
def out_path(self):
"""pcap file path - captured packets"""
return self._out_path
@property
def in_path(self):
""" pcap file path - injected packets"""
return self._in_path
@property
def capture_cli(self):
"""CLI string to start capture on this interface"""
return self._capture_cli
@property
def cap_name(self):
"""capture name for this interface"""
return self._cap_name
@property
def input_cli(self):
"""CLI string to load the injected packets"""
if self._nb_replays is not None:
return "%s limit %d" % (self._input_cli, self._nb_replays)
if self._worker is not None:
return "%s worker %d" % (self._input_cli, self._worker)
return self._input_cli
@property
def in_history_counter(self):
"""Self-incrementing counter used when renaming old pcap files"""
v = self._in_history_counter
self._in_history_counter += 1
return v
@property
def out_history_counter(self):
"""Self-incrementing counter used when renaming old pcap files"""
v = self._out_history_counter
self._out_history_counter += 1
return v
def __init__(self, test, pg_index, gso, gso_size):
""" Create VPP packet-generator interface """
super(VppPGInterface, self).__init__(test)
r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
self.set_sw_if_index(r.sw_if_index)
self._in_history_counter = 0
self._out_history_counter = 0
self._out_assert_counter = 0
self._pg_index = pg_index
self._gso_enabled = gso
self._gso_size = gso_size
self._out_file = "pg%u_out.pcap" % self.pg_index
self._out_path = self.test.tempdir + "/" + self._out_file
self._in_file = "pg%u_in.pcap" % self.pg_index
self._in_path = self.test.tempdir + "/" + self._in_file
self._capture_cli = "packet-generator capture pg%u pcap %s" % (
self.pg_index, self.out_path)
self._cap_name = "pcap%u-sw_if_index-%s" % (
self.pg_index, self.sw_if_index)
self._input_cli = \
"packet-generator new pcap %s source pg%u name %s" % (
self.in_path, self.pg_index, self.cap_name)
self._nb_replays = None
def _rename_previous_capture_file(self, path, counter, file):
# if a file from a previous capture exists, rename it.
try:
if os.path.isfile(path):
name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
(self.test.tempdir,
time.time(),
self.name,
counter,
file)
self.test.logger.debug("Renaming %s->%s" %
(path, name))
os.rename(path, name)
except OSError:
self.test.logger.debug("OSError: Could not rename %s %s" %
(path, file))
def enable_capture(self):
""" Enable capture on this packet-generator interface
of at most n packets.
If n < 0, this is no limit
"""
# disable the capture to flush the capture
self.disable_capture()
self._rename_previous_capture_file(self.out_path,
self.out_history_counter,
self._out_file)
# FIXME this should be an API, but no such exists atm
self.test.vapi.cli(self.capture_cli)
self._pcap_reader = None
def disable_capture(self):
self.test.vapi.cli("%s disable" % self.capture_cli)
def add_stream(self, pkts, nb_replays=None, worker=None):
"""
Add a stream of packets to this packet-generator
:param pkts: iterable packets
"""
self._worker = worker
self._nb_replays = nb_replays
self._rename_previous_capture_file(self.in_path,
self.in_history_counter,
self._in_file)
wrpcap(self.in_path, pkts)
self.test.register_capture(self.cap_name)
# FIXME this should be an API, but no such exists atm
self.test.vapi.cli(self.input_cli)
def generate_debug_aid(self, kind):
""" Create a hardlink to the out file with a counter and a file
containing stack trace to ease debugging in case of multiple capture
files present. """
self.test.logger.debug("Generating debug aid for %s on %s" %
(kind, self._name))
link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
(self.test.tempdir, self._name,
self._out_assert_counter, kind, suffix)
for suffix in ["pcap", "stack"]
]
os.link(self.out_path, link_path)
with open(stack_path, "w") as f:
f.writelines(format_stack())
self._out_assert_counter += 1
def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
""" Helper method to get capture and filter it """
try:
if not self.wait_for_capture_file(timeout):
return None
output = rdpcap(self.out_path)
self.test.logger.debug("Capture has %s packets" % len(output.res))
except:
self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
(self.out_path, format_exc()))
return None
before = len(output.res)
if filter_out_fn:
output.res = [p for p in output.res if not filter_out_fn(p)]
removed = before - len(output.res)
if removed:
self.test.logger.debug(
"Filtered out %s packets from capture (returning %s)" %
(removed, len(output.res)))
return output
def get_capture(self, expected_count=None, remark=None, timeout=1,
filter_out_fn=is_ipv6_misc):
""" Get captured packets
:param expected_count: expected number of packets to capture, if None,
then self.test.packet_count_for_dst_pg_idx is
used to lookup the expected count
:param remark: remark printed into debug logs
:param timeout: how long to wait for packets
:param filter_out_fn: filter applied to each packet, packets for which
the filter returns True are removed from capture
:returns: iterable packets
"""
remaining_time = timeout
capture = None
name = self.name if remark is None else "%s (%s)" % (self.name, remark)
based_on = "based on provided argument"
if expected_count is None:
expected_count = \
self.test.get_packet_count_for_if_idx(self.sw_if_index)
based_on = "based on stored packet_infos"
if expected_count == 0:
raise Exception(
"Internal error, expected packet count for %s is 0!" %
name)
self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
expected_count, based_on, name))
while remaining_time > 0:
before = time.time()
capture = self._get_capture(remaining_time, filter_out_fn)
elapsed_time = time.time() - before
if capture:
if len(capture.res) == expected_count:
# bingo, got the packets we expected
return capture
elif len(capture.res) > expected_count:
self.test.logger.error(
ppc("Unexpected packets captured:", capture))
break
else:
self.test.logger.debug("Partial capture containing %s "
"packets doesn't match expected "
"count %s (yet?)" %
(len(capture.res), expected_count))
elif expected_count == 0:
# bingo, got None as we expected - return empty capture
return PacketList()
remaining_time -= elapsed_time
if capture:
self.generate_debug_aid("count-mismatch")
raise Exception("Captured packets mismatch, captured %s packets, "
"expected %s packets on %s" %
(len(capture.res), expected_count, name))
else:
raise Exception("No packets captured on %s" % name)
def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
""" Assert that nothing unfiltered was captured on interface
:param remark: remark printed into debug logs
:param filter_out_fn: filter applied to each packet, packets for which
the filter returns True are removed from capture
"""
if os.path.isfile(self.out_path):
try:
capture = self.get_capture(
0, remark=remark, filter_out_fn=filter_out_fn)
if not capture or len(capture.res) == 0:
# junk filtered out, we're good
return
except:
pass
self.generate_debug_aid("empty-assert")
if remark:
raise AssertionError(
"Non-empty capture file present for interface %s (%s)" %
(self.name, remark))
else:
raise AssertionError("Capture file present for interface %s" %
self.name)
def wait_for_capture_file(self, timeout=1):
"""
Wait until pcap capture file appears
:param timeout: How long to wait for the packet (default 1s)
:returns: True/False if the file is present or appears within timeout
"""
deadline = time.time() + timeout
if not os.path.isfile(self.out_path):
self.test.logger.debug("Waiting for capture file %s to appear, "
"timeout is %ss" % (self.out_path, timeout))
else:
self.test.logger.debug("Capture file %s already exists" %
self.out_path)
return True
while time.time() < deadline:
if os.path.isfile(self.out_path):
break
self._test.sleep(0) # yield
if os.path.isfile(self.out_path):
self.test.logger.debug("Capture file appeared after %fs" %
(time.time() - (deadline - timeout)))
else:
self.test.logger.debug("Timeout - capture file still nowhere")
return False
return True
def verify_enough_packet_data_in_pcap(self):
"""
Check if enough data is available in file handled by internal pcap
reader so that a whole packet can be read.
:returns: True if enough data present, else False
"""
orig_pos = self._pcap_reader.f.tell() # save file position
enough_data = False
# read packet header from pcap
packet_header_size = 16
caplen = None
end_pos = None
hdr = self._pcap_reader.f.read(packet_header_size)
if len(hdr) == packet_header_size:
# parse the capture length - caplen
sec, usec, caplen, wirelen = struct.unpack(
self._pcap_reader.endian + "IIII", hdr)
self._pcap_reader.f.seek(0, 2) # seek to end of file
end_pos = self._pcap_reader.f.tell() # get position at end
if end_pos >= orig_pos + len(hdr) + caplen:
enough_data = True # yay, we have enough data
self._pcap_reader.f.seek(orig_pos, 0) # restore original position
return enough_data
def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
"""
Wait for next packet captured with a timeout
:param timeout: How long to wait for the packet
:returns: Captured packet if no packet arrived within timeout
:raises Exception: if no packet arrives within timeout
"""
deadline = time.time() + timeout
if self._pcap_reader is None:
if not self.wait_for_capture_file(timeout):
raise CaptureTimeoutError("Capture file %s did not appear "
"within timeout" % self.out_path)
while time.time() < deadline:
try:
self._pcap_reader = PcapReader(self.out_path)
break
except:
self.test.logger.debug(
"Exception in scapy.PcapReader(%s): %s" %
(self.out_path, format_exc()))
if not self._pcap_reader:
raise CaptureTimeoutError("Capture file %s did not appear within "
"timeout" % self.out_path)
poll = False
if timeout > 0:
self.test.logger.debug("Waiting for packet")
else:
poll = True
self.test.logger.debug("Polling for packet")
while time.time() < deadline or poll:
if not self.verify_enough_packet_data_in_pcap():
self._test.sleep(0) # yield
poll = False
continue
p = self._pcap_reader.recv()
if p is not None:
if filter_out_fn is not None and filter_out_fn(p):
self.test.logger.debug(
"Packet received after %ss was filtered out" %
(time.time() - (deadline - timeout)))
else:
self.test.logger.debug(
"Packet received after %fs" %
(time.time() - (deadline - timeout)))
return p
self._test.sleep(0) # yield
poll = False
self.test.logger.debug("Timeout - no packets received")
raise CaptureTimeoutError("Packet didn't arrive within timeout")
def create_arp_req(self):
"""Create ARP request applicable for this interface"""
return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
ARP(op=ARP.who_has, pdst=self.local_ip4,
psrc=self.remote_ip4, hwsrc=self.remote_mac))
def create_ndp_req(self):
"""Create NDP - NS applicable for this interface"""
nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
d = inet_ntop(socket.AF_INET6, nsma)
return (Ether(dst=in6_getnsmac(nsma)) /
IPv6(dst=d, src=self.remote_ip6) /
ICMPv6ND_NS(tgt=self.local_ip6) /
ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
def resolve_arp(self, pg_interface=None):
"""Resolve ARP using provided packet-generator interface
:param pg_interface: interface used to resolve, if None then this
interface is used
"""
if pg_interface is None:
pg_interface = self
self.test.logger.info("Sending ARP request for %s on port %s" %
(self.local_ip4, pg_interface.name))
arp_req = self.create_arp_req()
pg_interface.add_stream(arp_req)
pg_interface.enable_capture()
self.test.pg_start()
self.test.logger.info(self.test.vapi.cli("show trace"))
try:
captured_packet = pg_interface.wait_for_packet(1)
except:
self.test.logger.info("No ARP received on port %s" %
pg_interface.name)
return
arp_reply = captured_packet.copy() # keep original for exception
try:
if arp_reply[ARP].op == ARP.is_at:
self.test.logger.info("VPP %s MAC address is %s " %
(self.name, arp_reply[ARP].hwsrc))
self._local_mac = arp_reply[ARP].hwsrc
else:
self.test.logger.info("No ARP received on port %s" %
pg_interface.name)
except:
self.test.logger.error(
ppp("Unexpected response to ARP request:", captured_packet))
raise
def resolve_ndp(self, pg_interface=None, timeout=1):
"""Resolve NDP using provided packet-generator interface
:param pg_interface: interface used to resolve, if None then this
interface is used
: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")
