test/vpp_pg_interface.py

   1 import os
   2 import time
   3 import socket
   4 import struct
   5 from traceback import format_exc, format_stack
   6
   7 import scapy.compat
   8 from scapy.utils import wrpcap, rdpcap, PcapReader
   9 from scapy.plist import PacketList
  10 from vpp_interface import VppInterface
  11
  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, \
  15     IPv6ExtHdrHopByHop
  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
  19
  20
  21 class CaptureTimeoutError(Exception):
  22     """ Exception raised if capture or packet doesn't appear within timeout """
  23     pass
  24
  25
  26 def is_ipv6_misc(p):
  27     """ Is packet one of uninteresting IPv6 broadcasts? """
  28     if p.haslayer(ICMPv6ND_RA):
  29         if in6_ismaddr(p[IPv6].dst):
  30             return True
  31     if p.haslayer(IPv6ExtHdrHopByHop):
  32         for o in p[IPv6ExtHdrHopByHop].options:
  33             if isinstance(o, RouterAlert):
  34                 return True
  35     return False
  36
  37
  38 class VppPGInterface(VppInterface):
  39     """
  40     VPP packet-generator interface
  41     """
  42
  43     @property
  44     def pg_index(self):
  45         """packet-generator interface index assigned by VPP"""
  46         return self._pg_index
  47
  48     @property
  49     def out_path(self):
  50         """pcap file path - captured packets"""
  51         return self._out_path
  52
  53     @property
  54     def in_path(self):
  55         """ pcap file path - injected packets"""
  56         return self._in_path
  57
  58     @property
  59     def capture_cli(self):
  60         """CLI string to start capture on this interface"""
  61         return self._capture_cli
  62
  63     @property
  64     def cap_name(self):
  65         """capture name for this interface"""
  66         return self._cap_name
  67
  68     @property
  69     def input_cli(self):
  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
  74
  75     @property
  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
  80         return v
  81
  82     @property
  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
  87         return v
  88
  89     def __init__(self, test, pg_index):
  90         """ Create VPP packet-generator interface """
  91         super(VppPGInterface, self).__init__(test)
  92
  93         r = test.vapi.pg_create_interface(pg_index)
  94         self.set_sw_if_index(r.sw_if_index)
  95
  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
 107         self._input_cli = \
 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
 111
 112     def enable_capture(self):
 113         """ Enable capture on this packet-generator interface
 114             of at most n packets.
 115             If n < 0, this is no limit
 116         """
 117         try:
 118             if os.path.isfile(self.out_path):
 119                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 120                     (self.test.tempdir,
 121                      time.time(),
 122                      self.name,
 123                      self.out_history_counter,
 124                      self._out_file)
 125                 self.test.logger.debug("Renaming %s->%s" %
 126                                        (self.out_path, name))
 127                 os.rename(self.out_path, name)
 128         except:
 129             pass
 130         # FIXME this should be an API, but no such exists atm
 131         self.test.vapi.cli(self.capture_cli)
 132         self._pcap_reader = None
 133
 134     def disable_capture(self):
 135         self.test.vapi.cli("%s disable" % self.capture_cli)
 136
 137     def add_stream(self, pkts, nb_replays=None):
 138         """
 139         Add a stream of packets to this packet-generator
 140
 141         :param pkts: iterable packets
 142
 143         """
 144         self._nb_replays = nb_replays
 145         try:
 146             if os.path.isfile(self.in_path):
 147                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %\
 148                     (self.test.tempdir,
 149                      time.time(),
 150                      self.name,
 151                      self.in_history_counter,
 152                      self._in_file)
 153                 self.test.logger.debug("Renaming %s->%s" %
 154                                        (self.in_path, name))
 155                 os.rename(self.in_path, name)
 156         except:
 157             pass
 158         wrpcap(self.in_path, pkts)
 159         self.test.register_capture(self.cap_name)
 160         # FIXME this should be an API, but no such exists atm
 161         self.test.vapi.cli(self.input_cli)
 162
 163     def generate_debug_aid(self, kind):
 164         """ Create a hardlink to the out file with a counter and a file
 165         containing stack trace to ease debugging in case of multiple capture
 166         files present. """
 167         self.test.logger.debug("Generating debug aid for %s on %s" %
 168                                (kind, self._name))
 169         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 170                                  (self.test.tempdir, self._name,
 171                                   self._out_assert_counter, kind, suffix)
 172                                  for suffix in ["pcap", "stack"]
 173                                  ]
 174         os.link(self.out_path, link_path)
 175         with open(stack_path, "w") as f:
 176             f.writelines(format_stack())
 177         self._out_assert_counter += 1
 178
 179     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 180         """ Helper method to get capture and filter it """
 181         try:
 182             if not self.wait_for_capture_file(timeout):
 183                 return None
 184             output = rdpcap(self.out_path)
 185             self.test.logger.debug("Capture has %s packets" % len(output.res))
 186         except:
 187             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 188                                    (self.out_path, format_exc()))
 189             return None
 190         before = len(output.res)
 191         if filter_out_fn:
 192             output.res = [p for p in output.res if not filter_out_fn(p)]
 193         removed = before - len(output.res)
 194         if removed:
 195             self.test.logger.debug(
 196                 "Filtered out %s packets from capture (returning %s)" %
 197                 (removed, len(output.res)))
 198         return output
 199
 200     def get_capture(self, expected_count=None, remark=None, timeout=1,
 201                     filter_out_fn=is_ipv6_misc):
 202         """ Get captured packets
 203
 204         :param expected_count: expected number of packets to capture, if None,
 205                                then self.test.packet_count_for_dst_pg_idx is
 206                                used to lookup the expected count
 207         :param remark: remark printed into debug logs
 208         :param timeout: how long to wait for packets
 209         :param filter_out_fn: filter applied to each packet, packets for which
 210                               the filter returns True are removed from capture
 211         :returns: iterable packets
 212         """
 213         remaining_time = timeout
 214         capture = None
 215         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 216         based_on = "based on provided argument"
 217         if expected_count is None:
 218             expected_count = \
 219                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 220             based_on = "based on stored packet_infos"
 221             if expected_count == 0:
 222                 raise Exception(
 223                     "Internal error, expected packet count for %s is 0!" %
 224                     name)
 225         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 226             expected_count, based_on, name))
 227         while remaining_time > 0:
 228             before = time.time()
 229             capture = self._get_capture(remaining_time, filter_out_fn)
 230             elapsed_time = time.time() - before
 231             if capture:
 232                 if len(capture.res) == expected_count:
 233                     # bingo, got the packets we expected
 234                     return capture
 235                 elif len(capture.res) > expected_count:
 236                     self.test.logger.error(
 237                         ppc("Unexpected packets captured:", capture))
 238                     break
 239                 else:
 240                     self.test.logger.debug("Partial capture containing %s "
 241                                            "packets doesn't match expected "
 242                                            "count %s (yet?)" %
 243                                            (len(capture.res), expected_count))
 244             elif expected_count == 0:
 245                 # bingo, got None as we expected - return empty capture
 246                 return PacketList()
 247             remaining_time -= elapsed_time
 248         if capture:
 249             self.generate_debug_aid("count-mismatch")
 250             raise Exception("Captured packets mismatch, captured %s packets, "
 251                             "expected %s packets on %s" %
 252                             (len(capture.res), expected_count, name))
 253         else:
 254             raise Exception("No packets captured on %s" % name)
 255
 256     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 257         """ Assert that nothing unfiltered was captured on interface
 258
 259         :param remark: remark printed into debug logs
 260         :param filter_out_fn: filter applied to each packet, packets for which
 261                               the filter returns True are removed from capture
 262         """
 263         if os.path.isfile(self.out_path):
 264             try:
 265                 capture = self.get_capture(
 266                     0, remark=remark, filter_out_fn=filter_out_fn)
 267                 if not capture or len(capture.res) == 0:
 268                     # junk filtered out, we're good
 269                     return
 270             except:
 271                 pass
 272             self.generate_debug_aid("empty-assert")
 273             if remark:
 274                 raise AssertionError(
 275                     "Non-empty capture file present for interface %s (%s)" %
 276                     (self.name, remark))
 277             else:
 278                 raise AssertionError("Capture file present for interface %s" %
 279                                      self.name)
 280
 281     def wait_for_capture_file(self, timeout=1):
 282         """
 283         Wait until pcap capture file appears
 284
 285         :param timeout: How long to wait for the packet (default 1s)
 286
 287         :returns: True/False if the file is present or appears within timeout
 288         """
 289         deadline = time.time() + timeout
 290         if not os.path.isfile(self.out_path):
 291             self.test.logger.debug("Waiting for capture file %s to appear, "
 292                                    "timeout is %ss" % (self.out_path, timeout))
 293         else:
 294             self.test.logger.debug("Capture file %s already exists" %
 295                                    self.out_path)
 296             return True
 297         while time.time() < deadline:
 298             if os.path.isfile(self.out_path):
 299                 break
 300             self._test.sleep(0)  # yield
 301         if os.path.isfile(self.out_path):
 302             self.test.logger.debug("Capture file appeared after %fs" %
 303                                    (time.time() - (deadline - timeout)))
 304         else:
 305             self.test.logger.debug("Timeout - capture file still nowhere")
 306             return False
 307         return True
 308
 309     def verify_enough_packet_data_in_pcap(self):
 310         """
 311         Check if enough data is available in file handled by internal pcap
 312         reader so that a whole packet can be read.
 313
 314         :returns: True if enough data present, else False
 315         """
 316         orig_pos = self._pcap_reader.f.tell()  # save file position
 317         enough_data = False
 318         # read packet header from pcap
 319         packet_header_size = 16
 320         caplen = None
 321         end_pos = None
 322         hdr = self._pcap_reader.f.read(packet_header_size)
 323         if len(hdr) == packet_header_size:
 324             # parse the capture length - caplen
 325             sec, usec, caplen, wirelen = struct.unpack(
 326                 self._pcap_reader.endian + "IIII", hdr)
 327             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 328             end_pos = self._pcap_reader.f.tell()  # get position at end
 329             if end_pos >= orig_pos + len(hdr) + caplen:
 330                 enough_data = True  # yay, we have enough data
 331         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 332         return enough_data
 333
 334     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 335         """
 336         Wait for next packet captured with a timeout
 337
 338         :param timeout: How long to wait for the packet
 339
 340         :returns: Captured packet if no packet arrived within timeout
 341         :raises Exception: if no packet arrives within timeout
 342         """
 343         deadline = time.time() + timeout
 344         if self._pcap_reader is None:
 345             if not self.wait_for_capture_file(timeout):
 346                 raise CaptureTimeoutError("Capture file %s did not appear "
 347                                           "within timeout" % self.out_path)
 348             while time.time() < deadline:
 349                 try:
 350                     self._pcap_reader = PcapReader(self.out_path)
 351                     break
 352                 except:
 353                     self.test.logger.debug(
 354                         "Exception in scapy.PcapReader(%s): %s" %
 355                         (self.out_path, format_exc()))
 356         if not self._pcap_reader:
 357             raise CaptureTimeoutError("Capture file %s did not appear within "
 358                                       "timeout" % self.out_path)
 359
 360         poll = False
 361         if timeout > 0:
 362             self.test.logger.debug("Waiting for packet")
 363         else:
 364             poll = True
 365             self.test.logger.debug("Polling for packet")
 366         while time.time() < deadline or poll:
 367             if not self.verify_enough_packet_data_in_pcap():
 368                 self._test.sleep(0)  # yield
 369                 poll = False
 370                 continue
 371             p = self._pcap_reader.recv()
 372             if p is not None:
 373                 if filter_out_fn is not None and filter_out_fn(p):
 374                     self.test.logger.debug(
 375                         "Packet received after %ss was filtered out" %
 376                         (time.time() - (deadline - timeout)))
 377                 else:
 378                     self.test.logger.debug(
 379                         "Packet received after %fs" %
 380                         (time.time() - (deadline - timeout)))
 381                     return p
 382             self._test.sleep(0)  # yield
 383             poll = False
 384         self.test.logger.debug("Timeout - no packets received")
 385         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 386
 387     def create_arp_req(self):
 388         """Create ARP request applicable for this interface"""
 389         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 390                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 391                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 392
 393     def create_ndp_req(self):
 394         """Create NDP - NS applicable for this interface"""
 395         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 396         d = inet_ntop(socket.AF_INET6, nsma)
 397
 398         return (Ether(dst=in6_getnsmac(nsma)) /
 399                 IPv6(dst=d, src=self.remote_ip6) /
 400                 ICMPv6ND_NS(tgt=self.local_ip6) /
 401                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 402
 403     def resolve_arp(self, pg_interface=None):
 404         """Resolve ARP using provided packet-generator interface
 405
 406         :param pg_interface: interface used to resolve, if None then this
 407             interface is used
 408
 409         """
 410         if pg_interface is None:
 411             pg_interface = self
 412         self.test.logger.info("Sending ARP request for %s on port %s" %
 413                               (self.local_ip4, pg_interface.name))
 414         arp_req = self.create_arp_req()
 415         pg_interface.add_stream(arp_req)
 416         pg_interface.enable_capture()
 417         self.test.pg_start()
 418         self.test.logger.info(self.test.vapi.cli("show trace"))
 419         try:
 420             captured_packet = pg_interface.wait_for_packet(1)
 421         except:
 422             self.test.logger.info("No ARP received on port %s" %
 423                                   pg_interface.name)
 424             return
 425         arp_reply = captured_packet.copy()  # keep original for exception
 426         # Make Dot1AD packet content recognizable to scapy
 427         if arp_reply.type == 0x88a8:
 428             arp_reply.type = 0x8100
 429             arp_reply = Ether(scapy.compat.raw(arp_reply))
 430         try:
 431             if arp_reply[ARP].op == ARP.is_at:
 432                 self.test.logger.info("VPP %s MAC address is %s " %
 433                                       (self.name, arp_reply[ARP].hwsrc))
 434                 self._local_mac = arp_reply[ARP].hwsrc
 435             else:
 436                 self.test.logger.info("No ARP received on port %s" %
 437                                       pg_interface.name)
 438         except:
 439             self.test.logger.error(
 440                 ppp("Unexpected response to ARP request:", captured_packet))
 441             raise
 442
 443     def resolve_ndp(self, pg_interface=None, timeout=1):
 444         """Resolve NDP using provided packet-generator interface
 445
 446         :param pg_interface: interface used to resolve, if None then this
 447             interface is used
 448         :param timeout: how long to wait for response before giving up
 449
 450         """
 451         if pg_interface is None:
 452             pg_interface = self
 453         self.test.logger.info("Sending NDP request for %s on port %s" %
 454                               (self.local_ip6, pg_interface.name))
 455         ndp_req = self.create_ndp_req()
 456         pg_interface.add_stream(ndp_req)
 457         pg_interface.enable_capture()
 458         self.test.pg_start()
 459         now = time.time()
 460         deadline = now + timeout
 461         # Enabling IPv6 on an interface can generate more than the
 462         # ND reply we are looking for (namely MLD). So loop through
 463         # the replies to look for want we want.
 464         while now < deadline:
 465             try:
 466                 captured_packet = pg_interface.wait_for_packet(
 467                     deadline - now, filter_out_fn=None)
 468             except:
 469                 self.test.logger.error(
 470                     "Timeout while waiting for NDP response")
 471                 raise
 472             ndp_reply = captured_packet.copy()  # keep original for exception
 473             # Make Dot1AD packet content recognizable to scapy
 474             if ndp_reply.type == 0x88a8:
 475                 self._test.logger.info(
 476                     "Replacing EtherType: 0x88a8 with "
 477                     "0x8100 and regenerating Ethernet header. ")
 478                 ndp_reply.type = 0x8100
 479                 ndp_reply = Ether(scapy.compat.raw(ndp_reply))
 480             try:
 481                 ndp_na = ndp_reply[ICMPv6ND_NA]
 482                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 483                 self.test.logger.info("VPP %s MAC address is %s " %
 484                                       (self.name, opt.lladdr))
 485                 self._local_mac = opt.lladdr
 486                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 487                 # we now have the MAC we've been after
 488                 return
 489             except:
 490                 self.test.logger.info(
 491                     ppp("Unexpected response to NDP request:",
 492                         captured_packet))
 493             now = time.time()
 494
 495         self.test.logger.debug(self.test.vapi.cli("show trace"))
 496         raise Exception("Timeout while waiting for NDP response")