5 from traceback import format_exc, format_stack
8 from scapy.utils import wrpcap, rdpcap, PcapReader
9 from scapy.plist import PacketList
10 from vpp_interface import VppInterface
12 from scapy.layers.l2 import Ether, ARP
13 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
14 ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
16 from util import ppp, ppc
17 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
18 from scapy.utils import inet_pton, inet_ntop
21 class CaptureTimeoutError(Exception):
22 """ Exception raised if capture or packet doesn't appear within timeout """
27 """ Is packet one of uninteresting IPv6 broadcasts? """
28 if p.haslayer(ICMPv6ND_RA):
29 if in6_ismaddr(p[IPv6].dst):
31 if p.haslayer(IPv6ExtHdrHopByHop):
32 for o in p[IPv6ExtHdrHopByHop].options:
33 if isinstance(o, RouterAlert):
38 class VppPGInterface(VppInterface):
40 VPP packet-generator interface
45 """packet-generator interface index assigned by VPP"""
49 def gso_enabled(self):
50 """gso enabled on packet-generator interface"""
51 if self._gso_enabled == 0:
57 """gso size on packet-generator interface"""
62 """pcap file path - captured packets"""
67 """ pcap file path - injected packets"""
71 def capture_cli(self):
72 """CLI string to start capture on this interface"""
73 return self._capture_cli
77 """capture name for this interface"""
82 """CLI string to load the injected packets"""
83 if self._nb_replays is not None:
84 return "%s limit %d" % (self._input_cli, self._nb_replays)
85 return self._input_cli
88 def in_history_counter(self):
89 """Self-incrementing counter used when renaming old pcap files"""
90 v = self._in_history_counter
91 self._in_history_counter += 1
95 def out_history_counter(self):
96 """Self-incrementing counter used when renaming old pcap files"""
97 v = self._out_history_counter
98 self._out_history_counter += 1
101 def __init__(self, test, pg_index, gso, gso_size):
102 """ Create VPP packet-generator interface """
103 super(VppPGInterface, self).__init__(test)
105 r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
106 self.set_sw_if_index(r.sw_if_index)
108 self._in_history_counter = 0
109 self._out_history_counter = 0
110 self._out_assert_counter = 0
111 self._pg_index = pg_index
112 self._gso_enabled = gso
113 self._gso_size = gso_size
114 self._out_file = "pg%u_out.pcap" % self.pg_index
115 self._out_path = self.test.tempdir + "/" + self._out_file
116 self._in_file = "pg%u_in.pcap" % self.pg_index
117 self._in_path = self.test.tempdir + "/" + self._in_file
118 self._capture_cli = "packet-generator capture pg%u pcap %s" % (
119 self.pg_index, self.out_path)
120 self._cap_name = "pcap%u-sw_if_index-%s" % (
121 self.pg_index, self.sw_if_index)
123 "packet-generator new pcap %s source pg%u name %s" % (
124 self.in_path, self.pg_index, self.cap_name)
125 self._nb_replays = None
127 def _rename_previous_capture_file(self, path, counter, file):
128 # if a file from a previous capture exists, rename it.
130 if os.path.isfile(path):
131 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
137 self.test.logger.debug("Renaming %s->%s" %
139 os.rename(path, name)
141 self.test.logger.debug("OSError: Could not rename %s %s" %
144 def enable_capture(self):
145 """ Enable capture on this packet-generator interface
146 of at most n packets.
147 If n < 0, this is no limit
150 self._rename_previous_capture_file(self.out_path,
151 self.out_history_counter,
153 # FIXME this should be an API, but no such exists atm
154 self.test.vapi.cli(self.capture_cli)
155 self._pcap_reader = None
157 def disable_capture(self):
158 self.test.vapi.cli("%s disable" % self.capture_cli)
160 def add_stream(self, pkts, nb_replays=None):
162 Add a stream of packets to this packet-generator
164 :param pkts: iterable packets
167 self._nb_replays = nb_replays
168 self._rename_previous_capture_file(self.in_path,
169 self.in_history_counter,
171 wrpcap(self.in_path, pkts)
172 self.test.register_capture(self.cap_name)
173 # FIXME this should be an API, but no such exists atm
174 self.test.vapi.cli(self.input_cli)
176 def generate_debug_aid(self, kind):
177 """ Create a hardlink to the out file with a counter and a file
178 containing stack trace to ease debugging in case of multiple capture
180 self.test.logger.debug("Generating debug aid for %s on %s" %
182 link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
183 (self.test.tempdir, self._name,
184 self._out_assert_counter, kind, suffix)
185 for suffix in ["pcap", "stack"]
187 os.link(self.out_path, link_path)
188 with open(stack_path, "w") as f:
189 f.writelines(format_stack())
190 self._out_assert_counter += 1
192 def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
193 """ Helper method to get capture and filter it """
195 if not self.wait_for_capture_file(timeout):
197 output = rdpcap(self.out_path)
198 self.test.logger.debug("Capture has %s packets" % len(output.res))
200 self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
201 (self.out_path, format_exc()))
203 before = len(output.res)
205 output.res = [p for p in output.res if not filter_out_fn(p)]
206 removed = before - len(output.res)
208 self.test.logger.debug(
209 "Filtered out %s packets from capture (returning %s)" %
210 (removed, len(output.res)))
213 def get_capture(self, expected_count=None, remark=None, timeout=1,
214 filter_out_fn=is_ipv6_misc):
215 """ Get captured packets
217 :param expected_count: expected number of packets to capture, if None,
218 then self.test.packet_count_for_dst_pg_idx is
219 used to lookup the expected count
220 :param remark: remark printed into debug logs
221 :param timeout: how long to wait for packets
222 :param filter_out_fn: filter applied to each packet, packets for which
223 the filter returns True are removed from capture
224 :returns: iterable packets
226 remaining_time = timeout
228 name = self.name if remark is None else "%s (%s)" % (self.name, remark)
229 based_on = "based on provided argument"
230 if expected_count is None:
232 self.test.get_packet_count_for_if_idx(self.sw_if_index)
233 based_on = "based on stored packet_infos"
234 if expected_count == 0:
236 "Internal error, expected packet count for %s is 0!" %
238 self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
239 expected_count, based_on, name))
240 while remaining_time > 0:
242 capture = self._get_capture(remaining_time, filter_out_fn)
243 elapsed_time = time.time() - before
245 if len(capture.res) == expected_count:
246 # bingo, got the packets we expected
248 elif len(capture.res) > expected_count:
249 self.test.logger.error(
250 ppc("Unexpected packets captured:", capture))
253 self.test.logger.debug("Partial capture containing %s "
254 "packets doesn't match expected "
256 (len(capture.res), expected_count))
257 elif expected_count == 0:
258 # bingo, got None as we expected - return empty capture
260 remaining_time -= elapsed_time
262 self.generate_debug_aid("count-mismatch")
263 raise Exception("Captured packets mismatch, captured %s packets, "
264 "expected %s packets on %s" %
265 (len(capture.res), expected_count, name))
267 raise Exception("No packets captured on %s" % name)
269 def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
270 """ Assert that nothing unfiltered was captured on interface
272 :param remark: remark printed into debug logs
273 :param filter_out_fn: filter applied to each packet, packets for which
274 the filter returns True are removed from capture
276 if os.path.isfile(self.out_path):
278 capture = self.get_capture(
279 0, remark=remark, filter_out_fn=filter_out_fn)
280 if not capture or len(capture.res) == 0:
281 # junk filtered out, we're good
285 self.generate_debug_aid("empty-assert")
287 raise AssertionError(
288 "Non-empty capture file present for interface %s (%s)" %
291 raise AssertionError("Capture file present for interface %s" %
294 def wait_for_capture_file(self, timeout=1):
296 Wait until pcap capture file appears
298 :param timeout: How long to wait for the packet (default 1s)
300 :returns: True/False if the file is present or appears within timeout
302 deadline = time.time() + timeout
303 if not os.path.isfile(self.out_path):
304 self.test.logger.debug("Waiting for capture file %s to appear, "
305 "timeout is %ss" % (self.out_path, timeout))
307 self.test.logger.debug("Capture file %s already exists" %
310 while time.time() < deadline:
311 if os.path.isfile(self.out_path):
313 self._test.sleep(0) # yield
314 if os.path.isfile(self.out_path):
315 self.test.logger.debug("Capture file appeared after %fs" %
316 (time.time() - (deadline - timeout)))
318 self.test.logger.debug("Timeout - capture file still nowhere")
322 def verify_enough_packet_data_in_pcap(self):
324 Check if enough data is available in file handled by internal pcap
325 reader so that a whole packet can be read.
327 :returns: True if enough data present, else False
329 orig_pos = self._pcap_reader.f.tell() # save file position
331 # read packet header from pcap
332 packet_header_size = 16
335 hdr = self._pcap_reader.f.read(packet_header_size)
336 if len(hdr) == packet_header_size:
337 # parse the capture length - caplen
338 sec, usec, caplen, wirelen = struct.unpack(
339 self._pcap_reader.endian + "IIII", hdr)
340 self._pcap_reader.f.seek(0, 2) # seek to end of file
341 end_pos = self._pcap_reader.f.tell() # get position at end
342 if end_pos >= orig_pos + len(hdr) + caplen:
343 enough_data = True # yay, we have enough data
344 self._pcap_reader.f.seek(orig_pos, 0) # restore original position
347 def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
349 Wait for next packet captured with a timeout
351 :param timeout: How long to wait for the packet
353 :returns: Captured packet if no packet arrived within timeout
354 :raises Exception: if no packet arrives within timeout
356 deadline = time.time() + timeout
357 if self._pcap_reader is None:
358 if not self.wait_for_capture_file(timeout):
359 raise CaptureTimeoutError("Capture file %s did not appear "
360 "within timeout" % self.out_path)
361 while time.time() < deadline:
363 self._pcap_reader = PcapReader(self.out_path)
366 self.test.logger.debug(
367 "Exception in scapy.PcapReader(%s): %s" %
368 (self.out_path, format_exc()))
369 if not self._pcap_reader:
370 raise CaptureTimeoutError("Capture file %s did not appear within "
371 "timeout" % self.out_path)
375 self.test.logger.debug("Waiting for packet")
378 self.test.logger.debug("Polling for packet")
379 while time.time() < deadline or poll:
380 if not self.verify_enough_packet_data_in_pcap():
381 self._test.sleep(0) # yield
384 p = self._pcap_reader.recv()
386 if filter_out_fn is not None and filter_out_fn(p):
387 self.test.logger.debug(
388 "Packet received after %ss was filtered out" %
389 (time.time() - (deadline - timeout)))
391 self.test.logger.debug(
392 "Packet received after %fs" %
393 (time.time() - (deadline - timeout)))
395 self._test.sleep(0) # yield
397 self.test.logger.debug("Timeout - no packets received")
398 raise CaptureTimeoutError("Packet didn't arrive within timeout")
400 def create_arp_req(self):
401 """Create ARP request applicable for this interface"""
402 return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
403 ARP(op=ARP.who_has, pdst=self.local_ip4,
404 psrc=self.remote_ip4, hwsrc=self.remote_mac))
406 def create_ndp_req(self):
407 """Create NDP - NS applicable for this interface"""
408 nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
409 d = inet_ntop(socket.AF_INET6, nsma)
411 return (Ether(dst=in6_getnsmac(nsma)) /
412 IPv6(dst=d, src=self.remote_ip6) /
413 ICMPv6ND_NS(tgt=self.local_ip6) /
414 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
416 def resolve_arp(self, pg_interface=None):
417 """Resolve ARP using provided packet-generator interface
419 :param pg_interface: interface used to resolve, if None then this
423 if pg_interface is None:
425 self.test.logger.info("Sending ARP request for %s on port %s" %
426 (self.local_ip4, pg_interface.name))
427 arp_req = self.create_arp_req()
428 pg_interface.add_stream(arp_req)
429 pg_interface.enable_capture()
431 self.test.logger.info(self.test.vapi.cli("show trace"))
433 captured_packet = pg_interface.wait_for_packet(1)
435 self.test.logger.info("No ARP received on port %s" %
438 arp_reply = captured_packet.copy() # keep original for exception
440 if arp_reply[ARP].op == ARP.is_at:
441 self.test.logger.info("VPP %s MAC address is %s " %
442 (self.name, arp_reply[ARP].hwsrc))
443 self._local_mac = arp_reply[ARP].hwsrc
445 self.test.logger.info("No ARP received on port %s" %
448 self.test.logger.error(
449 ppp("Unexpected response to ARP request:", captured_packet))
452 def resolve_ndp(self, pg_interface=None, timeout=1):
453 """Resolve NDP using provided packet-generator interface
455 :param pg_interface: interface used to resolve, if None then this
457 :param timeout: how long to wait for response before giving up
460 if pg_interface is None:
462 self.test.logger.info("Sending NDP request for %s on port %s" %
463 (self.local_ip6, pg_interface.name))
464 ndp_req = self.create_ndp_req()
465 pg_interface.add_stream(ndp_req)
466 pg_interface.enable_capture()
469 deadline = now + timeout
470 # Enabling IPv6 on an interface can generate more than the
471 # ND reply we are looking for (namely MLD). So loop through
472 # the replies to look for want we want.
473 while now < deadline:
475 captured_packet = pg_interface.wait_for_packet(
476 deadline - now, filter_out_fn=None)
478 self.test.logger.error(
479 "Timeout while waiting for NDP response")
481 ndp_reply = captured_packet.copy() # keep original for exception
483 ndp_na = ndp_reply[ICMPv6ND_NA]
484 opt = ndp_na[ICMPv6NDOptDstLLAddr]
485 self.test.logger.info("VPP %s MAC address is %s " %
486 (self.name, opt.lladdr))
487 self._local_mac = opt.lladdr
488 self.test.logger.debug(self.test.vapi.cli("show trace"))
489 # we now have the MAC we've been after
492 self.test.logger.info(
493 ppp("Unexpected response to NDP request:",
497 self.test.logger.debug(self.test.vapi.cli("show trace"))
498 raise Exception("Timeout while waiting for NDP response")