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"""
50 """pcap file path - captured packets"""
55 """ pcap file path - injected packets"""
59 def capture_cli(self):
60 """CLI string to start capture on this interface"""
61 return self._capture_cli
65 """capture name for this interface"""
70 """CLI string to load the injected packets"""
71 if self._nb_replays is not None:
72 return "%s limit %d" % (self._input_cli, self._nb_replays)
73 return self._input_cli
76 def in_history_counter(self):
77 """Self-incrementing counter used when renaming old pcap files"""
78 v = self._in_history_counter
79 self._in_history_counter += 1
83 def out_history_counter(self):
84 """Self-incrementing counter used when renaming old pcap files"""
85 v = self._out_history_counter
86 self._out_history_counter += 1
89 def __init__(self, test, pg_index):
90 """ Create VPP packet-generator interface """
91 super(VppPGInterface, self).__init__(test)
93 r = test.vapi.pg_create_interface(pg_index)
94 self.set_sw_if_index(r.sw_if_index)
96 self._in_history_counter = 0
97 self._out_history_counter = 0
98 self._out_assert_counter = 0
99 self._pg_index = pg_index
100 self._out_file = "pg%u_out.pcap" % self.pg_index
101 self._out_path = self.test.tempdir + "/" + self._out_file
102 self._in_file = "pg%u_in.pcap" % self.pg_index
103 self._in_path = self.test.tempdir + "/" + self._in_file
104 self._capture_cli = "packet-generator capture pg%u pcap %s" % (
105 self.pg_index, self.out_path)
106 self._cap_name = "pcap%u-sw_if_index-%s" % (
107 self.pg_index, self.sw_if_index)
109 "packet-generator new pcap %s source pg%u name %s" % (
110 self.in_path, self.pg_index, self.cap_name)
111 self._nb_replays = None
113 def _rename_previous_capture_file(self, path, counter, file):
114 # if a file from a previous capture exists, rename it.
116 if os.path.isfile(path):
117 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
123 self.test.logger.debug("Renaming %s->%s" %
125 os.rename(path, name)
127 self.test.logger.debug("OSError: Could not rename %s %s" %
130 def enable_capture(self):
131 """ Enable capture on this packet-generator interface
132 of at most n packets.
133 If n < 0, this is no limit
136 self._rename_previous_capture_file(self.out_path,
137 self.out_history_counter,
139 # FIXME this should be an API, but no such exists atm
140 self.test.vapi.cli(self.capture_cli)
141 self._pcap_reader = None
143 def disable_capture(self):
144 self.test.vapi.cli("%s disable" % self.capture_cli)
146 def add_stream(self, pkts, nb_replays=None):
148 Add a stream of packets to this packet-generator
150 :param pkts: iterable packets
153 self._nb_replays = nb_replays
154 self._rename_previous_capture_file(self.in_path,
155 self.in_history_counter,
157 wrpcap(self.in_path, pkts)
158 self.test.register_capture(self.cap_name)
159 # FIXME this should be an API, but no such exists atm
160 self.test.vapi.cli(self.input_cli)
162 def generate_debug_aid(self, kind):
163 """ Create a hardlink to the out file with a counter and a file
164 containing stack trace to ease debugging in case of multiple capture
166 self.test.logger.debug("Generating debug aid for %s on %s" %
168 link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
169 (self.test.tempdir, self._name,
170 self._out_assert_counter, kind, suffix)
171 for suffix in ["pcap", "stack"]
173 os.link(self.out_path, link_path)
174 with open(stack_path, "w") as f:
175 f.writelines(format_stack())
176 self._out_assert_counter += 1
178 def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
179 """ Helper method to get capture and filter it """
181 if not self.wait_for_capture_file(timeout):
183 output = rdpcap(self.out_path)
184 self.test.logger.debug("Capture has %s packets" % len(output.res))
186 self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
187 (self.out_path, format_exc()))
189 before = len(output.res)
191 output.res = [p for p in output.res if not filter_out_fn(p)]
192 removed = before - len(output.res)
194 self.test.logger.debug(
195 "Filtered out %s packets from capture (returning %s)" %
196 (removed, len(output.res)))
199 def get_capture(self, expected_count=None, remark=None, timeout=1,
200 filter_out_fn=is_ipv6_misc):
201 """ Get captured packets
203 :param expected_count: expected number of packets to capture, if None,
204 then self.test.packet_count_for_dst_pg_idx is
205 used to lookup the expected count
206 :param remark: remark printed into debug logs
207 :param timeout: how long to wait for packets
208 :param filter_out_fn: filter applied to each packet, packets for which
209 the filter returns True are removed from capture
210 :returns: iterable packets
212 remaining_time = timeout
214 name = self.name if remark is None else "%s (%s)" % (self.name, remark)
215 based_on = "based on provided argument"
216 if expected_count is None:
218 self.test.get_packet_count_for_if_idx(self.sw_if_index)
219 based_on = "based on stored packet_infos"
220 if expected_count == 0:
222 "Internal error, expected packet count for %s is 0!" %
224 self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
225 expected_count, based_on, name))
226 while remaining_time > 0:
228 capture = self._get_capture(remaining_time, filter_out_fn)
229 elapsed_time = time.time() - before
231 if len(capture.res) == expected_count:
232 # bingo, got the packets we expected
234 elif len(capture.res) > expected_count:
235 self.test.logger.error(
236 ppc("Unexpected packets captured:", capture))
239 self.test.logger.debug("Partial capture containing %s "
240 "packets doesn't match expected "
242 (len(capture.res), expected_count))
243 elif expected_count == 0:
244 # bingo, got None as we expected - return empty capture
246 remaining_time -= elapsed_time
248 self.generate_debug_aid("count-mismatch")
249 raise Exception("Captured packets mismatch, captured %s packets, "
250 "expected %s packets on %s" %
251 (len(capture.res), expected_count, name))
253 raise Exception("No packets captured on %s" % name)
255 def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
256 """ Assert that nothing unfiltered was captured on interface
258 :param remark: remark printed into debug logs
259 :param filter_out_fn: filter applied to each packet, packets for which
260 the filter returns True are removed from capture
262 if os.path.isfile(self.out_path):
264 capture = self.get_capture(
265 0, remark=remark, filter_out_fn=filter_out_fn)
266 if not capture or len(capture.res) == 0:
267 # junk filtered out, we're good
271 self.generate_debug_aid("empty-assert")
273 raise AssertionError(
274 "Non-empty capture file present for interface %s (%s)" %
277 raise AssertionError("Capture file present for interface %s" %
280 def wait_for_capture_file(self, timeout=1):
282 Wait until pcap capture file appears
284 :param timeout: How long to wait for the packet (default 1s)
286 :returns: True/False if the file is present or appears within timeout
288 deadline = time.time() + timeout
289 if not os.path.isfile(self.out_path):
290 self.test.logger.debug("Waiting for capture file %s to appear, "
291 "timeout is %ss" % (self.out_path, timeout))
293 self.test.logger.debug("Capture file %s already exists" %
296 while time.time() < deadline:
297 if os.path.isfile(self.out_path):
299 self._test.sleep(0) # yield
300 if os.path.isfile(self.out_path):
301 self.test.logger.debug("Capture file appeared after %fs" %
302 (time.time() - (deadline - timeout)))
304 self.test.logger.debug("Timeout - capture file still nowhere")
308 def verify_enough_packet_data_in_pcap(self):
310 Check if enough data is available in file handled by internal pcap
311 reader so that a whole packet can be read.
313 :returns: True if enough data present, else False
315 orig_pos = self._pcap_reader.f.tell() # save file position
317 # read packet header from pcap
318 packet_header_size = 16
321 hdr = self._pcap_reader.f.read(packet_header_size)
322 if len(hdr) == packet_header_size:
323 # parse the capture length - caplen
324 sec, usec, caplen, wirelen = struct.unpack(
325 self._pcap_reader.endian + "IIII", hdr)
326 self._pcap_reader.f.seek(0, 2) # seek to end of file
327 end_pos = self._pcap_reader.f.tell() # get position at end
328 if end_pos >= orig_pos + len(hdr) + caplen:
329 enough_data = True # yay, we have enough data
330 self._pcap_reader.f.seek(orig_pos, 0) # restore original position
333 def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
335 Wait for next packet captured with a timeout
337 :param timeout: How long to wait for the packet
339 :returns: Captured packet if no packet arrived within timeout
340 :raises Exception: if no packet arrives within timeout
342 deadline = time.time() + timeout
343 if self._pcap_reader is None:
344 if not self.wait_for_capture_file(timeout):
345 raise CaptureTimeoutError("Capture file %s did not appear "
346 "within timeout" % self.out_path)
347 while time.time() < deadline:
349 self._pcap_reader = PcapReader(self.out_path)
352 self.test.logger.debug(
353 "Exception in scapy.PcapReader(%s): %s" %
354 (self.out_path, format_exc()))
355 if not self._pcap_reader:
356 raise CaptureTimeoutError("Capture file %s did not appear within "
357 "timeout" % self.out_path)
361 self.test.logger.debug("Waiting for packet")
364 self.test.logger.debug("Polling for packet")
365 while time.time() < deadline or poll:
366 if not self.verify_enough_packet_data_in_pcap():
367 self._test.sleep(0) # yield
370 p = self._pcap_reader.recv()
372 if filter_out_fn is not None and filter_out_fn(p):
373 self.test.logger.debug(
374 "Packet received after %ss was filtered out" %
375 (time.time() - (deadline - timeout)))
377 self.test.logger.debug(
378 "Packet received after %fs" %
379 (time.time() - (deadline - timeout)))
381 self._test.sleep(0) # yield
383 self.test.logger.debug("Timeout - no packets received")
384 raise CaptureTimeoutError("Packet didn't arrive within timeout")
386 def create_arp_req(self):
387 """Create ARP request applicable for this interface"""
388 return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
389 ARP(op=ARP.who_has, pdst=self.local_ip4,
390 psrc=self.remote_ip4, hwsrc=self.remote_mac))
392 def create_ndp_req(self):
393 """Create NDP - NS applicable for this interface"""
394 nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
395 d = inet_ntop(socket.AF_INET6, nsma)
397 return (Ether(dst=in6_getnsmac(nsma)) /
398 IPv6(dst=d, src=self.remote_ip6) /
399 ICMPv6ND_NS(tgt=self.local_ip6) /
400 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
402 def resolve_arp(self, pg_interface=None):
403 """Resolve ARP using provided packet-generator interface
405 :param pg_interface: interface used to resolve, if None then this
409 if pg_interface is None:
411 self.test.logger.info("Sending ARP request for %s on port %s" %
412 (self.local_ip4, pg_interface.name))
413 arp_req = self.create_arp_req()
414 pg_interface.add_stream(arp_req)
415 pg_interface.enable_capture()
417 self.test.logger.info(self.test.vapi.cli("show trace"))
419 captured_packet = pg_interface.wait_for_packet(1)
421 self.test.logger.info("No ARP received on port %s" %
424 arp_reply = captured_packet.copy() # keep original for exception
426 if arp_reply[ARP].op == ARP.is_at:
427 self.test.logger.info("VPP %s MAC address is %s " %
428 (self.name, arp_reply[ARP].hwsrc))
429 self._local_mac = arp_reply[ARP].hwsrc
431 self.test.logger.info("No ARP received on port %s" %
434 self.test.logger.error(
435 ppp("Unexpected response to ARP request:", captured_packet))
438 def resolve_ndp(self, pg_interface=None, timeout=1):
439 """Resolve NDP using provided packet-generator interface
441 :param pg_interface: interface used to resolve, if None then this
443 :param timeout: how long to wait for response before giving up
446 if pg_interface is None:
448 self.test.logger.info("Sending NDP request for %s on port %s" %
449 (self.local_ip6, pg_interface.name))
450 ndp_req = self.create_ndp_req()
451 pg_interface.add_stream(ndp_req)
452 pg_interface.enable_capture()
455 deadline = now + timeout
456 # Enabling IPv6 on an interface can generate more than the
457 # ND reply we are looking for (namely MLD). So loop through
458 # the replies to look for want we want.
459 while now < deadline:
461 captured_packet = pg_interface.wait_for_packet(
462 deadline - now, filter_out_fn=None)
464 self.test.logger.error(
465 "Timeout while waiting for NDP response")
467 ndp_reply = captured_packet.copy() # keep original for exception
469 ndp_na = ndp_reply[ICMPv6ND_NA]
470 opt = ndp_na[ICMPv6NDOptDstLLAddr]
471 self.test.logger.info("VPP %s MAC address is %s " %
472 (self.name, opt.lladdr))
473 self._local_mac = opt.lladdr
474 self.test.logger.debug(self.test.vapi.cli("show trace"))
475 # we now have the MAC we've been after
478 self.test.logger.info(
479 ppp("Unexpected response to NDP request:",
483 self.test.logger.debug(self.test.vapi.cli("show trace"))
484 raise Exception("Timeout while waiting for NDP response")