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
149 # disable the capture to flush the capture
150 self.disable_capture()
151 self._rename_previous_capture_file(self.out_path,
152 self.out_history_counter,
154 # FIXME this should be an API, but no such exists atm
155 self.test.vapi.cli(self.capture_cli)
156 self._pcap_reader = None
158 def disable_capture(self):
159 self.test.vapi.cli("%s disable" % self.capture_cli)
161 def add_stream(self, pkts, nb_replays=None):
163 Add a stream of packets to this packet-generator
165 :param pkts: iterable packets
168 self._nb_replays = nb_replays
169 self._rename_previous_capture_file(self.in_path,
170 self.in_history_counter,
172 wrpcap(self.in_path, pkts)
173 self.test.register_capture(self.cap_name)
174 # FIXME this should be an API, but no such exists atm
175 self.test.vapi.cli(self.input_cli)
177 def generate_debug_aid(self, kind):
178 """ Create a hardlink to the out file with a counter and a file
179 containing stack trace to ease debugging in case of multiple capture
181 self.test.logger.debug("Generating debug aid for %s on %s" %
183 link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
184 (self.test.tempdir, self._name,
185 self._out_assert_counter, kind, suffix)
186 for suffix in ["pcap", "stack"]
188 os.link(self.out_path, link_path)
189 with open(stack_path, "w") as f:
190 f.writelines(format_stack())
191 self._out_assert_counter += 1
193 def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
194 """ Helper method to get capture and filter it """
196 if not self.wait_for_capture_file(timeout):
198 output = rdpcap(self.out_path)
199 self.test.logger.debug("Capture has %s packets" % len(output.res))
201 self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
202 (self.out_path, format_exc()))
204 before = len(output.res)
206 output.res = [p for p in output.res if not filter_out_fn(p)]
207 removed = before - len(output.res)
209 self.test.logger.debug(
210 "Filtered out %s packets from capture (returning %s)" %
211 (removed, len(output.res)))
214 def get_capture(self, expected_count=None, remark=None, timeout=1,
215 filter_out_fn=is_ipv6_misc):
216 """ Get captured packets
218 :param expected_count: expected number of packets to capture, if None,
219 then self.test.packet_count_for_dst_pg_idx is
220 used to lookup the expected count
221 :param remark: remark printed into debug logs
222 :param timeout: how long to wait for packets
223 :param filter_out_fn: filter applied to each packet, packets for which
224 the filter returns True are removed from capture
225 :returns: iterable packets
227 remaining_time = timeout
229 name = self.name if remark is None else "%s (%s)" % (self.name, remark)
230 based_on = "based on provided argument"
231 if expected_count is None:
233 self.test.get_packet_count_for_if_idx(self.sw_if_index)
234 based_on = "based on stored packet_infos"
235 if expected_count == 0:
237 "Internal error, expected packet count for %s is 0!" %
239 self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
240 expected_count, based_on, name))
241 while remaining_time > 0:
243 capture = self._get_capture(remaining_time, filter_out_fn)
244 elapsed_time = time.time() - before
246 if len(capture.res) == expected_count:
247 # bingo, got the packets we expected
249 elif len(capture.res) > expected_count:
250 self.test.logger.error(
251 ppc("Unexpected packets captured:", capture))
254 self.test.logger.debug("Partial capture containing %s "
255 "packets doesn't match expected "
257 (len(capture.res), expected_count))
258 elif expected_count == 0:
259 # bingo, got None as we expected - return empty capture
261 remaining_time -= elapsed_time
263 self.generate_debug_aid("count-mismatch")
264 raise Exception("Captured packets mismatch, captured %s packets, "
265 "expected %s packets on %s" %
266 (len(capture.res), expected_count, name))
268 raise Exception("No packets captured on %s" % name)
270 def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
271 """ Assert that nothing unfiltered was captured on interface
273 :param remark: remark printed into debug logs
274 :param filter_out_fn: filter applied to each packet, packets for which
275 the filter returns True are removed from capture
277 if os.path.isfile(self.out_path):
279 capture = self.get_capture(
280 0, remark=remark, filter_out_fn=filter_out_fn)
281 if not capture or len(capture.res) == 0:
282 # junk filtered out, we're good
286 self.generate_debug_aid("empty-assert")
288 raise AssertionError(
289 "Non-empty capture file present for interface %s (%s)" %
292 raise AssertionError("Capture file present for interface %s" %
295 def wait_for_capture_file(self, timeout=1):
297 Wait until pcap capture file appears
299 :param timeout: How long to wait for the packet (default 1s)
301 :returns: True/False if the file is present or appears within timeout
303 deadline = time.time() + timeout
304 if not os.path.isfile(self.out_path):
305 self.test.logger.debug("Waiting for capture file %s to appear, "
306 "timeout is %ss" % (self.out_path, timeout))
308 self.test.logger.debug("Capture file %s already exists" %
311 while time.time() < deadline:
312 if os.path.isfile(self.out_path):
314 self._test.sleep(0) # yield
315 if os.path.isfile(self.out_path):
316 self.test.logger.debug("Capture file appeared after %fs" %
317 (time.time() - (deadline - timeout)))
319 self.test.logger.debug("Timeout - capture file still nowhere")
323 def verify_enough_packet_data_in_pcap(self):
325 Check if enough data is available in file handled by internal pcap
326 reader so that a whole packet can be read.
328 :returns: True if enough data present, else False
330 orig_pos = self._pcap_reader.f.tell() # save file position
332 # read packet header from pcap
333 packet_header_size = 16
336 hdr = self._pcap_reader.f.read(packet_header_size)
337 if len(hdr) == packet_header_size:
338 # parse the capture length - caplen
339 sec, usec, caplen, wirelen = struct.unpack(
340 self._pcap_reader.endian + "IIII", hdr)
341 self._pcap_reader.f.seek(0, 2) # seek to end of file
342 end_pos = self._pcap_reader.f.tell() # get position at end
343 if end_pos >= orig_pos + len(hdr) + caplen:
344 enough_data = True # yay, we have enough data
345 self._pcap_reader.f.seek(orig_pos, 0) # restore original position
348 def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
350 Wait for next packet captured with a timeout
352 :param timeout: How long to wait for the packet
354 :returns: Captured packet if no packet arrived within timeout
355 :raises Exception: if no packet arrives within timeout
357 deadline = time.time() + timeout
358 if self._pcap_reader is None:
359 if not self.wait_for_capture_file(timeout):
360 raise CaptureTimeoutError("Capture file %s did not appear "
361 "within timeout" % self.out_path)
362 while time.time() < deadline:
364 self._pcap_reader = PcapReader(self.out_path)
367 self.test.logger.debug(
368 "Exception in scapy.PcapReader(%s): %s" %
369 (self.out_path, format_exc()))
370 if not self._pcap_reader:
371 raise CaptureTimeoutError("Capture file %s did not appear within "
372 "timeout" % self.out_path)
376 self.test.logger.debug("Waiting for packet")
379 self.test.logger.debug("Polling for packet")
380 while time.time() < deadline or poll:
381 if not self.verify_enough_packet_data_in_pcap():
382 self._test.sleep(0) # yield
385 p = self._pcap_reader.recv()
387 if filter_out_fn is not None and filter_out_fn(p):
388 self.test.logger.debug(
389 "Packet received after %ss was filtered out" %
390 (time.time() - (deadline - timeout)))
392 self.test.logger.debug(
393 "Packet received after %fs" %
394 (time.time() - (deadline - timeout)))
396 self._test.sleep(0) # yield
398 self.test.logger.debug("Timeout - no packets received")
399 raise CaptureTimeoutError("Packet didn't arrive within timeout")
401 def create_arp_req(self):
402 """Create ARP request applicable for this interface"""
403 return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
404 ARP(op=ARP.who_has, pdst=self.local_ip4,
405 psrc=self.remote_ip4, hwsrc=self.remote_mac))
407 def create_ndp_req(self):
408 """Create NDP - NS applicable for this interface"""
409 nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
410 d = inet_ntop(socket.AF_INET6, nsma)
412 return (Ether(dst=in6_getnsmac(nsma)) /
413 IPv6(dst=d, src=self.remote_ip6) /
414 ICMPv6ND_NS(tgt=self.local_ip6) /
415 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
417 def resolve_arp(self, pg_interface=None):
418 """Resolve ARP using provided packet-generator interface
420 :param pg_interface: interface used to resolve, if None then this
424 if pg_interface is None:
426 self.test.logger.info("Sending ARP request for %s on port %s" %
427 (self.local_ip4, pg_interface.name))
428 arp_req = self.create_arp_req()
429 pg_interface.add_stream(arp_req)
430 pg_interface.enable_capture()
432 self.test.logger.info(self.test.vapi.cli("show trace"))
434 captured_packet = pg_interface.wait_for_packet(1)
436 self.test.logger.info("No ARP received on port %s" %
439 arp_reply = captured_packet.copy() # keep original for exception
441 if arp_reply[ARP].op == ARP.is_at:
442 self.test.logger.info("VPP %s MAC address is %s " %
443 (self.name, arp_reply[ARP].hwsrc))
444 self._local_mac = arp_reply[ARP].hwsrc
446 self.test.logger.info("No ARP received on port %s" %
449 self.test.logger.error(
450 ppp("Unexpected response to ARP request:", captured_packet))
453 def resolve_ndp(self, pg_interface=None, timeout=1):
454 """Resolve NDP using provided packet-generator interface
456 :param pg_interface: interface used to resolve, if None then this
458 :param timeout: how long to wait for response before giving up
461 if pg_interface is None:
463 self.test.logger.info("Sending NDP request for %s on port %s" %
464 (self.local_ip6, pg_interface.name))
465 ndp_req = self.create_ndp_req()
466 pg_interface.add_stream(ndp_req)
467 pg_interface.enable_capture()
470 deadline = now + timeout
471 # Enabling IPv6 on an interface can generate more than the
472 # ND reply we are looking for (namely MLD). So loop through
473 # the replies to look for want we want.
474 while now < deadline:
476 captured_packet = pg_interface.wait_for_packet(
477 deadline - now, filter_out_fn=None)
479 self.test.logger.error(
480 "Timeout while waiting for NDP response")
482 ndp_reply = captured_packet.copy() # keep original for exception
484 ndp_na = ndp_reply[ICMPv6ND_NA]
485 opt = ndp_na[ICMPv6NDOptDstLLAddr]
486 self.test.logger.info("VPP %s MAC address is %s " %
487 (self.name, opt.lladdr))
488 self._local_mac = opt.lladdr
489 self.test.logger.debug(self.test.vapi.cli("show trace"))
490 # we now have the MAC we've been after
493 self.test.logger.info(
494 ppp("Unexpected response to NDP request:",
498 self.test.logger.debug(self.test.vapi.cli("show trace"))
499 raise Exception("Timeout while waiting for NDP response")