3 from socket import inet_pton, inet_ntop
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
20 class CaptureTimeoutError(Exception):
21 """ Exception raised if capture or packet doesn't appear within timeout """
26 """ Is packet one of uninteresting IPv6 broadcasts? """
27 if p.haslayer(ICMPv6ND_RA):
28 if in6_ismaddr(p[IPv6].dst):
30 if p.haslayer(IPv6ExtHdrHopByHop):
31 for o in p[IPv6ExtHdrHopByHop].options:
32 if isinstance(o, RouterAlert):
37 class VppPGInterface(VppInterface):
39 VPP packet-generator interface
44 """packet-generator interface index assigned by VPP"""
48 def gso_enabled(self):
49 """gso enabled on packet-generator interface"""
50 if self._gso_enabled == 0:
56 """gso size on packet-generator interface"""
61 """pcap file path - captured packets"""
66 """ pcap file path - injected packets"""
70 def capture_cli(self):
71 """CLI string to start capture on this interface"""
72 return self._capture_cli
76 """capture name for this interface"""
81 """CLI string to load the injected packets"""
82 if self._nb_replays is not None:
83 return "%s limit %d" % (self._input_cli, self._nb_replays)
84 if self._worker is not None:
85 return "%s worker %d" % (self._input_cli, self._worker)
86 return self._input_cli
89 def in_history_counter(self):
90 """Self-incrementing counter used when renaming old pcap files"""
91 v = self._in_history_counter
92 self._in_history_counter += 1
96 def out_history_counter(self):
97 """Self-incrementing counter used when renaming old pcap files"""
98 v = self._out_history_counter
99 self._out_history_counter += 1
102 def __init__(self, test, pg_index, gso, gso_size):
103 """ Create VPP packet-generator interface """
104 super(VppPGInterface, self).__init__(test)
106 r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
107 self.set_sw_if_index(r.sw_if_index)
109 self._in_history_counter = 0
110 self._out_history_counter = 0
111 self._out_assert_counter = 0
112 self._pg_index = pg_index
113 self._gso_enabled = gso
114 self._gso_size = gso_size
115 self._out_file = "pg%u_out.pcap" % self.pg_index
116 self._out_path = self.test.tempdir + "/" + self._out_file
117 self._in_file = "pg%u_in.pcap" % self.pg_index
118 self._in_path = self.test.tempdir + "/" + self._in_file
119 self._capture_cli = "packet-generator capture pg%u pcap %s" % (
120 self.pg_index, self.out_path)
121 self._cap_name = "pcap%u-sw_if_index-%s" % (
122 self.pg_index, self.sw_if_index)
124 "packet-generator new pcap %s source pg%u name %s" % (
125 self.in_path, self.pg_index, self.cap_name)
126 self._nb_replays = None
128 def _rename_previous_capture_file(self, path, counter, file):
129 # if a file from a previous capture exists, rename it.
131 if os.path.isfile(path):
132 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
138 self.test.logger.debug("Renaming %s->%s" %
140 os.rename(path, name)
142 self.test.logger.debug("OSError: Could not rename %s %s" %
145 def enable_capture(self):
146 """ Enable capture on this packet-generator interface
147 of at most n packets.
148 If n < 0, this is no limit
150 # disable the capture to flush the capture
151 self.disable_capture()
152 self._rename_previous_capture_file(self.out_path,
153 self.out_history_counter,
155 # FIXME this should be an API, but no such exists atm
156 self.test.vapi.cli(self.capture_cli)
157 self._pcap_reader = None
159 def disable_capture(self):
160 self.test.vapi.cli("%s disable" % self.capture_cli)
162 def add_stream(self, pkts, nb_replays=None, worker=None):
164 Add a stream of packets to this packet-generator
166 :param pkts: iterable packets
169 self._worker = worker
170 self._nb_replays = nb_replays
171 self._rename_previous_capture_file(self.in_path,
172 self.in_history_counter,
174 wrpcap(self.in_path, pkts)
175 self.test.register_capture(self.cap_name)
176 # FIXME this should be an API, but no such exists atm
177 self.test.vapi.cli(self.input_cli)
179 def generate_debug_aid(self, kind):
180 """ Create a hardlink to the out file with a counter and a file
181 containing stack trace to ease debugging in case of multiple capture
183 self.test.logger.debug("Generating debug aid for %s on %s" %
185 link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
186 (self.test.tempdir, self._name,
187 self._out_assert_counter, kind, suffix)
188 for suffix in ["pcap", "stack"]
190 os.link(self.out_path, link_path)
191 with open(stack_path, "w") as f:
192 f.writelines(format_stack())
193 self._out_assert_counter += 1
195 def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
196 """ Helper method to get capture and filter it """
198 if not self.wait_for_capture_file(timeout):
200 output = rdpcap(self.out_path)
201 self.test.logger.debug("Capture has %s packets" % len(output.res))
203 self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
204 (self.out_path, format_exc()))
206 before = len(output.res)
208 output.res = [p for p in output.res if not filter_out_fn(p)]
209 removed = before - len(output.res)
211 self.test.logger.debug(
212 "Filtered out %s packets from capture (returning %s)" %
213 (removed, len(output.res)))
216 def get_capture(self, expected_count=None, remark=None, timeout=1,
217 filter_out_fn=is_ipv6_misc):
218 """ Get captured packets
220 :param expected_count: expected number of packets to capture, if None,
221 then self.test.packet_count_for_dst_pg_idx is
222 used to lookup the expected count
223 :param remark: remark printed into debug logs
224 :param timeout: how long to wait for packets
225 :param filter_out_fn: filter applied to each packet, packets for which
226 the filter returns True are removed from capture
227 :returns: iterable packets
229 remaining_time = timeout
231 name = self.name if remark is None else "%s (%s)" % (self.name, remark)
232 based_on = "based on provided argument"
233 if expected_count is None:
235 self.test.get_packet_count_for_if_idx(self.sw_if_index)
236 based_on = "based on stored packet_infos"
237 if expected_count == 0:
239 "Internal error, expected packet count for %s is 0!" %
241 self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
242 expected_count, based_on, name))
243 while remaining_time > 0:
245 capture = self._get_capture(remaining_time, filter_out_fn)
246 elapsed_time = time.time() - before
248 if len(capture.res) == expected_count:
249 # bingo, got the packets we expected
251 elif len(capture.res) > expected_count:
252 self.test.logger.error(
253 ppc("Unexpected packets captured:", capture))
256 self.test.logger.debug("Partial capture containing %s "
257 "packets doesn't match expected "
259 (len(capture.res), expected_count))
260 elif expected_count == 0:
261 # bingo, got None as we expected - return empty capture
263 remaining_time -= elapsed_time
265 self.generate_debug_aid("count-mismatch")
266 raise Exception("Captured packets mismatch, captured %s packets, "
267 "expected %s packets on %s" %
268 (len(capture.res), expected_count, name))
270 raise Exception("No packets captured on %s" % name)
272 def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
273 """ Assert that nothing unfiltered was captured on interface
275 :param remark: remark printed into debug logs
276 :param filter_out_fn: filter applied to each packet, packets for which
277 the filter returns True are removed from capture
279 if os.path.isfile(self.out_path):
281 capture = self.get_capture(
282 0, remark=remark, filter_out_fn=filter_out_fn)
283 if not capture or len(capture.res) == 0:
284 # junk filtered out, we're good
288 self.generate_debug_aid("empty-assert")
290 raise AssertionError(
291 "Non-empty capture file present for interface %s (%s)" %
294 raise AssertionError("Capture file present for interface %s" %
297 def wait_for_pg_stop(self):
298 # wait till packet-generator is stopped
299 # "show packet-generator" while it is still running gives this:
300 # Name Enabled Count Parameters
301 # pcap0-sw_if_inde Yes 64 limit 64, ...
303 # also have a 5-minute timeout just in case things go terribly wrong...
304 deadline = time.time() + 300
305 while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
306 self._test.sleep(0.01) # yield
307 if time.time() > deadline:
308 self.test.logger.debug("Timeout waiting for pg to stop")
311 def wait_for_capture_file(self, timeout=1):
313 Wait until pcap capture file appears
315 :param timeout: How long to wait for the packet (default 1s)
317 :returns: True/False if the file is present or appears within timeout
319 self.wait_for_pg_stop()
320 deadline = time.time() + timeout
321 if not os.path.isfile(self.out_path):
322 self.test.logger.debug("Waiting for capture file %s to appear, "
323 "timeout is %ss" % (self.out_path, timeout))
325 self.test.logger.debug("Capture file %s already exists" %
328 while time.time() < deadline:
329 if os.path.isfile(self.out_path):
331 self._test.sleep(0) # yield
332 if os.path.isfile(self.out_path):
333 self.test.logger.debug("Capture file appeared after %fs" %
334 (time.time() - (deadline - timeout)))
336 self.test.logger.debug("Timeout - capture file still nowhere")
340 def verify_enough_packet_data_in_pcap(self):
342 Check if enough data is available in file handled by internal pcap
343 reader so that a whole packet can be read.
345 :returns: True if enough data present, else False
347 orig_pos = self._pcap_reader.f.tell() # save file position
349 # read packet header from pcap
350 packet_header_size = 16
353 hdr = self._pcap_reader.f.read(packet_header_size)
354 if len(hdr) == packet_header_size:
355 # parse the capture length - caplen
356 sec, usec, caplen, wirelen = struct.unpack(
357 self._pcap_reader.endian + "IIII", hdr)
358 self._pcap_reader.f.seek(0, 2) # seek to end of file
359 end_pos = self._pcap_reader.f.tell() # get position at end
360 if end_pos >= orig_pos + len(hdr) + caplen:
361 enough_data = True # yay, we have enough data
362 self._pcap_reader.f.seek(orig_pos, 0) # restore original position
365 def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
367 Wait for next packet captured with a timeout
369 :param timeout: How long to wait for the packet
371 :returns: Captured packet if no packet arrived within timeout
372 :raises Exception: if no packet arrives within timeout
374 deadline = time.time() + timeout
375 if self._pcap_reader is None:
376 if not self.wait_for_capture_file(timeout):
377 raise CaptureTimeoutError("Capture file %s did not appear "
378 "within timeout" % self.out_path)
379 while time.time() < deadline:
381 self._pcap_reader = PcapReader(self.out_path)
384 self.test.logger.debug(
385 "Exception in scapy.PcapReader(%s): %s" %
386 (self.out_path, format_exc()))
387 if not self._pcap_reader:
388 raise CaptureTimeoutError("Capture file %s did not appear within "
389 "timeout" % self.out_path)
393 self.test.logger.debug("Waiting for packet")
396 self.test.logger.debug("Polling for packet")
397 while time.time() < deadline or poll:
398 if not self.verify_enough_packet_data_in_pcap():
399 self._test.sleep(0) # yield
402 p = self._pcap_reader.recv()
404 if filter_out_fn is not None and filter_out_fn(p):
405 self.test.logger.debug(
406 "Packet received after %ss was filtered out" %
407 (time.time() - (deadline - timeout)))
409 self.test.logger.debug(
410 "Packet received after %fs" %
411 (time.time() - (deadline - timeout)))
413 self._test.sleep(0) # yield
415 self.test.logger.debug("Timeout - no packets received")
416 raise CaptureTimeoutError("Packet didn't arrive within timeout")
418 def create_arp_req(self):
419 """Create ARP request applicable for this interface"""
420 return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
421 ARP(op=ARP.who_has, pdst=self.local_ip4,
422 psrc=self.remote_ip4, hwsrc=self.remote_mac))
424 def create_ndp_req(self):
425 """Create NDP - NS applicable for this interface"""
426 nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
427 d = inet_ntop(socket.AF_INET6, nsma)
429 return (Ether(dst=in6_getnsmac(nsma)) /
430 IPv6(dst=d, src=self.remote_ip6) /
431 ICMPv6ND_NS(tgt=self.local_ip6) /
432 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
434 def resolve_arp(self, pg_interface=None):
435 """Resolve ARP using provided packet-generator interface
437 :param pg_interface: interface used to resolve, if None then this
441 if pg_interface is None:
443 self.test.logger.info("Sending ARP request for %s on port %s" %
444 (self.local_ip4, pg_interface.name))
445 arp_req = self.create_arp_req()
446 pg_interface.add_stream(arp_req)
447 pg_interface.enable_capture()
449 self.test.logger.info(self.test.vapi.cli("show trace"))
451 captured_packet = pg_interface.wait_for_packet(1)
453 self.test.logger.info("No ARP received on port %s" %
456 arp_reply = captured_packet.copy() # keep original for exception
458 if arp_reply[ARP].op == ARP.is_at:
459 self.test.logger.info("VPP %s MAC address is %s " %
460 (self.name, arp_reply[ARP].hwsrc))
461 self._local_mac = arp_reply[ARP].hwsrc
463 self.test.logger.info("No ARP received on port %s" %
466 self.test.logger.error(
467 ppp("Unexpected response to ARP request:", captured_packet))
470 def resolve_ndp(self, pg_interface=None, timeout=1):
471 """Resolve NDP using provided packet-generator interface
473 :param pg_interface: interface used to resolve, if None then this
475 :param timeout: how long to wait for response before giving up
478 if pg_interface is None:
480 self.test.logger.info("Sending NDP request for %s on port %s" %
481 (self.local_ip6, pg_interface.name))
482 ndp_req = self.create_ndp_req()
483 pg_interface.add_stream(ndp_req)
484 pg_interface.enable_capture()
487 deadline = now + timeout
488 # Enabling IPv6 on an interface can generate more than the
489 # ND reply we are looking for (namely MLD). So loop through
490 # the replies to look for want we want.
491 while now < deadline:
493 captured_packet = pg_interface.wait_for_packet(
494 deadline - now, filter_out_fn=None)
496 self.test.logger.error(
497 "Timeout while waiting for NDP response")
499 ndp_reply = captured_packet.copy() # keep original for exception
501 ndp_na = ndp_reply[ICMPv6ND_NA]
502 opt = ndp_na[ICMPv6NDOptDstLLAddr]
503 self.test.logger.info("VPP %s MAC address is %s " %
504 (self.name, opt.lladdr))
505 self._local_mac = opt.lladdr
506 self.test.logger.debug(self.test.vapi.cli("show trace"))
507 # we now have the MAC we've been after
510 self.test.logger.info(
511 ppp("Unexpected response to NDP request:",
515 self.test.logger.debug(self.test.vapi.cli("show trace"))
516 raise Exception("Timeout while waiting for NDP response")