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" % self.sw_if_index
108 "packet-generator new pcap %s source pg%u name %s" % (
109 self.in_path, self.pg_index, self.cap_name)
110 self._nb_replays = None
112 def _rename_previous_capture_file(self, path, counter, file):
113 # if a file from a previous capture exists, rename it.
115 if os.path.isfile(path):
116 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
122 self.test.logger.debug("Renaming %s->%s" %
124 os.rename(path, name)
126 self.test.logger.debug("OSError: Could not rename %s %s" %
129 def enable_capture(self):
130 """ Enable capture on this packet-generator interface
131 of at most n packets.
132 If n < 0, this is no limit
135 self._rename_previous_capture_file(self.out_path,
136 self.out_history_counter,
138 # FIXME this should be an API, but no such exists atm
139 self.test.vapi.cli(self.capture_cli)
140 self._pcap_reader = None
142 def disable_capture(self):
143 self.test.vapi.cli("%s disable" % self.capture_cli)
145 def add_stream(self, pkts, nb_replays=None):
147 Add a stream of packets to this packet-generator
149 :param pkts: iterable packets
152 self._nb_replays = nb_replays
153 self._rename_previous_capture_file(self.in_path,
154 self.in_history_counter,
156 wrpcap(self.in_path, pkts)
157 self.test.register_capture(self.cap_name)
158 # FIXME this should be an API, but no such exists atm
159 self.test.vapi.cli(self.input_cli)
161 def generate_debug_aid(self, kind):
162 """ Create a hardlink to the out file with a counter and a file
163 containing stack trace to ease debugging in case of multiple capture
165 self.test.logger.debug("Generating debug aid for %s on %s" %
167 link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
168 (self.test.tempdir, self._name,
169 self._out_assert_counter, kind, suffix)
170 for suffix in ["pcap", "stack"]
172 os.link(self.out_path, link_path)
173 with open(stack_path, "w") as f:
174 f.writelines(format_stack())
175 self._out_assert_counter += 1
177 def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
178 """ Helper method to get capture and filter it """
180 if not self.wait_for_capture_file(timeout):
182 output = rdpcap(self.out_path)
183 self.test.logger.debug("Capture has %s packets" % len(output.res))
185 self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
186 (self.out_path, format_exc()))
188 before = len(output.res)
190 output.res = [p for p in output.res if not filter_out_fn(p)]
191 removed = before - len(output.res)
193 self.test.logger.debug(
194 "Filtered out %s packets from capture (returning %s)" %
195 (removed, len(output.res)))
198 def get_capture(self, expected_count=None, remark=None, timeout=1,
199 filter_out_fn=is_ipv6_misc):
200 """ Get captured packets
202 :param expected_count: expected number of packets to capture, if None,
203 then self.test.packet_count_for_dst_pg_idx is
204 used to lookup the expected count
205 :param remark: remark printed into debug logs
206 :param timeout: how long to wait for packets
207 :param filter_out_fn: filter applied to each packet, packets for which
208 the filter returns True are removed from capture
209 :returns: iterable packets
211 remaining_time = timeout
213 name = self.name if remark is None else "%s (%s)" % (self.name, remark)
214 based_on = "based on provided argument"
215 if expected_count is None:
217 self.test.get_packet_count_for_if_idx(self.sw_if_index)
218 based_on = "based on stored packet_infos"
219 if expected_count == 0:
221 "Internal error, expected packet count for %s is 0!" %
223 self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
224 expected_count, based_on, name))
225 while remaining_time > 0:
227 capture = self._get_capture(remaining_time, filter_out_fn)
228 elapsed_time = time.time() - before
230 if len(capture.res) == expected_count:
231 # bingo, got the packets we expected
233 elif len(capture.res) > expected_count:
234 self.test.logger.error(
235 ppc("Unexpected packets captured:", capture))
238 self.test.logger.debug("Partial capture containing %s "
239 "packets doesn't match expected "
241 (len(capture.res), expected_count))
242 elif expected_count == 0:
243 # bingo, got None as we expected - return empty capture
245 remaining_time -= elapsed_time
247 self.generate_debug_aid("count-mismatch")
248 raise Exception("Captured packets mismatch, captured %s packets, "
249 "expected %s packets on %s" %
250 (len(capture.res), expected_count, name))
252 raise Exception("No packets captured on %s" % name)
254 def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
255 """ Assert that nothing unfiltered was captured on interface
257 :param remark: remark printed into debug logs
258 :param filter_out_fn: filter applied to each packet, packets for which
259 the filter returns True are removed from capture
261 if os.path.isfile(self.out_path):
263 capture = self.get_capture(
264 0, remark=remark, filter_out_fn=filter_out_fn)
265 if not capture or len(capture.res) == 0:
266 # junk filtered out, we're good
270 self.generate_debug_aid("empty-assert")
272 raise AssertionError(
273 "Non-empty capture file present for interface %s (%s)" %
276 raise AssertionError("Capture file present for interface %s" %
279 def wait_for_capture_file(self, timeout=1):
281 Wait until pcap capture file appears
283 :param timeout: How long to wait for the packet (default 1s)
285 :returns: True/False if the file is present or appears within timeout
287 deadline = time.time() + timeout
288 if not os.path.isfile(self.out_path):
289 self.test.logger.debug("Waiting for capture file %s to appear, "
290 "timeout is %ss" % (self.out_path, timeout))
292 self.test.logger.debug("Capture file %s already exists" %
295 while time.time() < deadline:
296 if os.path.isfile(self.out_path):
298 self._test.sleep(0) # yield
299 if os.path.isfile(self.out_path):
300 self.test.logger.debug("Capture file appeared after %fs" %
301 (time.time() - (deadline - timeout)))
303 self.test.logger.debug("Timeout - capture file still nowhere")
307 def verify_enough_packet_data_in_pcap(self):
309 Check if enough data is available in file handled by internal pcap
310 reader so that a whole packet can be read.
312 :returns: True if enough data present, else False
314 orig_pos = self._pcap_reader.f.tell() # save file position
316 # read packet header from pcap
317 packet_header_size = 16
320 hdr = self._pcap_reader.f.read(packet_header_size)
321 if len(hdr) == packet_header_size:
322 # parse the capture length - caplen
323 sec, usec, caplen, wirelen = struct.unpack(
324 self._pcap_reader.endian + "IIII", hdr)
325 self._pcap_reader.f.seek(0, 2) # seek to end of file
326 end_pos = self._pcap_reader.f.tell() # get position at end
327 if end_pos >= orig_pos + len(hdr) + caplen:
328 enough_data = True # yay, we have enough data
329 self._pcap_reader.f.seek(orig_pos, 0) # restore original position
332 def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
334 Wait for next packet captured with a timeout
336 :param timeout: How long to wait for the packet
338 :returns: Captured packet if no packet arrived within timeout
339 :raises Exception: if no packet arrives within timeout
341 deadline = time.time() + timeout
342 if self._pcap_reader is None:
343 if not self.wait_for_capture_file(timeout):
344 raise CaptureTimeoutError("Capture file %s did not appear "
345 "within timeout" % self.out_path)
346 while time.time() < deadline:
348 self._pcap_reader = PcapReader(self.out_path)
351 self.test.logger.debug(
352 "Exception in scapy.PcapReader(%s): %s" %
353 (self.out_path, format_exc()))
354 if not self._pcap_reader:
355 raise CaptureTimeoutError("Capture file %s did not appear within "
356 "timeout" % self.out_path)
360 self.test.logger.debug("Waiting for packet")
363 self.test.logger.debug("Polling for packet")
364 while time.time() < deadline or poll:
365 if not self.verify_enough_packet_data_in_pcap():
366 self._test.sleep(0) # yield
369 p = self._pcap_reader.recv()
371 if filter_out_fn is not None and filter_out_fn(p):
372 self.test.logger.debug(
373 "Packet received after %ss was filtered out" %
374 (time.time() - (deadline - timeout)))
376 self.test.logger.debug(
377 "Packet received after %fs" %
378 (time.time() - (deadline - timeout)))
380 self._test.sleep(0) # yield
382 self.test.logger.debug("Timeout - no packets received")
383 raise CaptureTimeoutError("Packet didn't arrive within timeout")
385 def create_arp_req(self):
386 """Create ARP request applicable for this interface"""
387 return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
388 ARP(op=ARP.who_has, pdst=self.local_ip4,
389 psrc=self.remote_ip4, hwsrc=self.remote_mac))
391 def create_ndp_req(self):
392 """Create NDP - NS applicable for this interface"""
393 nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
394 d = inet_ntop(socket.AF_INET6, nsma)
396 return (Ether(dst=in6_getnsmac(nsma)) /
397 IPv6(dst=d, src=self.remote_ip6) /
398 ICMPv6ND_NS(tgt=self.local_ip6) /
399 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
401 def resolve_arp(self, pg_interface=None):
402 """Resolve ARP using provided packet-generator interface
404 :param pg_interface: interface used to resolve, if None then this
408 if pg_interface is None:
410 self.test.logger.info("Sending ARP request for %s on port %s" %
411 (self.local_ip4, pg_interface.name))
412 arp_req = self.create_arp_req()
413 pg_interface.add_stream(arp_req)
414 pg_interface.enable_capture()
416 self.test.logger.info(self.test.vapi.cli("show trace"))
418 captured_packet = pg_interface.wait_for_packet(1)
420 self.test.logger.info("No ARP received on port %s" %
423 arp_reply = captured_packet.copy() # keep original for exception
425 if arp_reply[ARP].op == ARP.is_at:
426 self.test.logger.info("VPP %s MAC address is %s " %
427 (self.name, arp_reply[ARP].hwsrc))
428 self._local_mac = arp_reply[ARP].hwsrc
430 self.test.logger.info("No ARP received on port %s" %
433 self.test.logger.error(
434 ppp("Unexpected response to ARP request:", captured_packet))
437 def resolve_ndp(self, pg_interface=None, timeout=1):
438 """Resolve NDP using provided packet-generator interface
440 :param pg_interface: interface used to resolve, if None then this
442 :param timeout: how long to wait for response before giving up
445 if pg_interface is None:
447 self.test.logger.info("Sending NDP request for %s on port %s" %
448 (self.local_ip6, pg_interface.name))
449 ndp_req = self.create_ndp_req()
450 pg_interface.add_stream(ndp_req)
451 pg_interface.enable_capture()
454 deadline = now + timeout
455 # Enabling IPv6 on an interface can generate more than the
456 # ND reply we are looking for (namely MLD). So loop through
457 # the replies to look for want we want.
458 while now < deadline:
460 captured_packet = pg_interface.wait_for_packet(
461 deadline - now, filter_out_fn=None)
463 self.test.logger.error(
464 "Timeout while waiting for NDP response")
466 ndp_reply = captured_packet.copy() # keep original for exception
468 ndp_na = ndp_reply[ICMPv6ND_NA]
469 opt = ndp_na[ICMPv6NDOptDstLLAddr]
470 self.test.logger.info("VPP %s MAC address is %s " %
471 (self.name, opt.lladdr))
472 self._local_mac = opt.lladdr
473 self.test.logger.debug(self.test.vapi.cli("show trace"))
474 # we now have the MAC we've been after
477 self.test.logger.info(
478 ppp("Unexpected response to NDP request:",
482 self.test.logger.debug(self.test.vapi.cli("show trace"))
483 raise Exception("Timeout while waiting for NDP response")