test/vpp_pg_interface.py

   1 import os
   2 import socket
   3 from socket import inet_pton, inet_ntop
   4 import struct
   5 import time
   6 from traceback import format_exc, format_stack
   7
   8 import scapy.compat
   9 from scapy.utils import wrpcap, rdpcap, PcapReader
  10 from scapy.plist import PacketList
  11 from vpp_interface import VppInterface
  12
  13 from scapy.layers.l2 import Ether, ARP
  14 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
  15     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
  16     IPv6ExtHdrHopByHop
  17 from util import ppp, ppc
  18 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  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 gso_enabled(self):
  50         """gso enabled on packet-generator interface"""
  51         if self._gso_enabled == 0:
  52             return "gso-disabled"
  53         return "gso-enabled"
  54
  55     @property
  56     def gso_size(self):
  57         """gso size on packet-generator interface"""
  58         return self._gso_size
  59
  60     @property
  61     def coalesce_is_enabled(self):
  62         """coalesce enabled on packet-generator interface"""
  63         if self._coalesce_enabled == 0:
  64             return "coalesce-disabled"
  65         return "coalesce-enabled"
  66
  67     @property
  68     def out_path(self):
  69         """pcap file path - captured packets"""
  70         return self._out_path
  71
  72     def get_in_path(self, worker):
  73         """ pcap file path - injected packets"""
  74         if worker is not None:
  75             return "%s/pg%u_wrk%u_in.pcap" % (self.test.tempdir, self.pg_index,
  76                                               worker)
  77         return "%s/pg%u_in.pcap" % (self.test.tempdir, self.pg_index)
  78
  79     @property
  80     def capture_cli(self):
  81         """CLI string to start capture on this interface"""
  82         return self._capture_cli
  83
  84     def get_cap_name(self, worker=None):
  85         """return capture name for this interface and given worker"""
  86         if worker is not None:
  87             return self._cap_name + "-worker%d" % worker
  88         return self._cap_name
  89
  90     def get_input_cli(self, nb_replays=None, worker=None):
  91         """return CLI string to load the injected packets"""
  92         input_cli = "packet-generator new pcap %s source pg%u name %s" % (
  93             self.get_in_path(worker), self.pg_index, self.get_cap_name(worker))
  94         if nb_replays is not None:
  95             return "%s limit %d" % (input_cli, nb_replays)
  96         if worker is not None:
  97             return "%s worker %d" % (input_cli, worker)
  98         return input_cli
  99
 100     @property
 101     def in_history_counter(self):
 102         """Self-incrementing counter used when renaming old pcap files"""
 103         v = self._in_history_counter
 104         self._in_history_counter += 1
 105         return v
 106
 107     @property
 108     def out_history_counter(self):
 109         """Self-incrementing counter used when renaming old pcap files"""
 110         v = self._out_history_counter
 111         self._out_history_counter += 1
 112         return v
 113
 114     def __init__(self, test, pg_index, gso, gso_size):
 115         """ Create VPP packet-generator interface """
 116         super().__init__(test)
 117
 118         r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
 119         self.set_sw_if_index(r.sw_if_index)
 120
 121         self._in_history_counter = 0
 122         self._out_history_counter = 0
 123         self._out_assert_counter = 0
 124         self._pg_index = pg_index
 125         self._gso_enabled = gso
 126         self._gso_size = gso_size
 127         self._coalesce_enabled = 0
 128         self._out_file = "pg%u_out.pcap" % self.pg_index
 129         self._out_path = self.test.tempdir + "/" + self._out_file
 130         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 131             self.pg_index, self.out_path)
 132         self._cap_name = "pcap%u-sw_if_index-%s" % (
 133             self.pg_index, self.sw_if_index)
 134
 135     def rename_old_pcap_file(self, path, counter):
 136         filename = os.path.basename(path)
 137         try:
 138             if os.path.isfile(path):
 139                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 140                     (self.test.tempdir,
 141                      time.time(),
 142                      self.name,
 143                      counter,
 144                      filename)
 145                 self.test.logger.debug("Renaming %s->%s" %
 146                                        (path, name))
 147                 os.rename(path, name)
 148         except OSError:
 149             self.test.logger.debug("OSError: Could not rename %s %s" %
 150                                    (path, filename))
 151
 152     def enable_capture(self):
 153         """ Enable capture on this packet-generator interface
 154             of at most n packets.
 155             If n < 0, this is no limit
 156         """
 157         # disable the capture to flush the capture
 158         self.disable_capture()
 159         self.rename_old_pcap_file(self.out_path, self.out_history_counter)
 160         # FIXME this should be an API, but no such exists atm
 161         self.test.vapi.cli(self.capture_cli)
 162         self._pcap_reader = None
 163
 164     def disable_capture(self):
 165         self.test.vapi.cli("%s disable" % self.capture_cli)
 166
 167     def coalesce_enable(self):
 168         """ Enable packet coalesce on this packet-generator interface"""
 169         self._coalesce_enabled = 1
 170         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 171                                                             1)
 172
 173     def coalesce_disable(self):
 174         """ Disable packet coalesce on this packet-generator interface"""
 175         self._coalesce_enabled = 0
 176         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 177                                                             0)
 178
 179     def add_stream(self, pkts, nb_replays=None, worker=None):
 180         """
 181         Add a stream of packets to this packet-generator
 182
 183         :param pkts: iterable packets
 184
 185         """
 186         wrpcap(self.get_in_path(worker), pkts)
 187         self.test.register_pcap(self, worker)
 188         # FIXME this should be an API, but no such exists atm
 189         self.test.vapi.cli(self.get_input_cli(nb_replays, worker))
 190
 191     def generate_debug_aid(self, kind):
 192         """ Create a hardlink to the out file with a counter and a file
 193         containing stack trace to ease debugging in case of multiple capture
 194         files present. """
 195         self.test.logger.debug("Generating debug aid for %s on %s" %
 196                                (kind, self._name))
 197         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 198                                  (self.test.tempdir, self._name,
 199                                   self._out_assert_counter, kind, suffix)
 200                                  for suffix in ["pcap", "stack"]
 201                                  ]
 202         os.link(self.out_path, link_path)
 203         with open(stack_path, "w") as f:
 204             f.writelines(format_stack())
 205         self._out_assert_counter += 1
 206
 207     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 208         """ Helper method to get capture and filter it """
 209         try:
 210             if not self.wait_for_capture_file(timeout):
 211                 return None
 212             output = rdpcap(self.out_path)
 213             self.test.logger.debug("Capture has %s packets" % len(output.res))
 214         except:
 215             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 216                                    (self.out_path, format_exc()))
 217             return None
 218         before = len(output.res)
 219         if filter_out_fn:
 220             output.res = [p for p in output.res if not filter_out_fn(p)]
 221         removed = before - len(output.res)
 222         if removed:
 223             self.test.logger.debug(
 224                 "Filtered out %s packets from capture (returning %s)" %
 225                 (removed, len(output.res)))
 226         return output
 227
 228     def get_capture(self, expected_count=None, remark=None, timeout=1,
 229                     filter_out_fn=is_ipv6_misc):
 230         """ Get captured packets
 231
 232         :param expected_count: expected number of packets to capture, if None,
 233                                then self.test.packet_count_for_dst_pg_idx is
 234                                used to lookup the expected count
 235         :param remark: remark printed into debug logs
 236         :param timeout: how long to wait for packets
 237         :param filter_out_fn: filter applied to each packet, packets for which
 238                               the filter returns True are removed from capture
 239         :returns: iterable packets
 240         """
 241         remaining_time = timeout
 242         capture = None
 243         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 244         based_on = "based on provided argument"
 245         if expected_count is None:
 246             expected_count = \
 247                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 248             based_on = "based on stored packet_infos"
 249             if expected_count == 0:
 250                 raise Exception(
 251                     "Internal error, expected packet count for %s is 0!" %
 252                     name)
 253         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 254             expected_count, based_on, name))
 255         while remaining_time > 0:
 256             before = time.time()
 257             capture = self._get_capture(remaining_time, filter_out_fn)
 258             elapsed_time = time.time() - before
 259             if capture:
 260                 if len(capture.res) == expected_count:
 261                     # bingo, got the packets we expected
 262                     return capture
 263                 elif len(capture.res) > expected_count:
 264                     self.test.logger.error(
 265                         ppc("Unexpected packets captured:", capture))
 266                     break
 267                 else:
 268                     self.test.logger.debug("Partial capture containing %s "
 269                                            "packets doesn't match expected "
 270                                            "count %s (yet?)" %
 271                                            (len(capture.res), expected_count))
 272             elif expected_count == 0:
 273                 # bingo, got None as we expected - return empty capture
 274                 return PacketList()
 275             remaining_time -= elapsed_time
 276         if capture:
 277             self.generate_debug_aid("count-mismatch")
 278             raise Exception("Captured packets mismatch, captured %s packets, "
 279                             "expected %s packets on %s" %
 280                             (len(capture.res), expected_count, name))
 281         else:
 282             raise Exception("No packets captured on %s" % name)
 283
 284     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 285         """ Assert that nothing unfiltered was captured on interface
 286
 287         :param remark: remark printed into debug logs
 288         :param filter_out_fn: filter applied to each packet, packets for which
 289                               the filter returns True are removed from capture
 290         """
 291         if os.path.isfile(self.out_path):
 292             try:
 293                 capture = self.get_capture(
 294                     0, remark=remark, filter_out_fn=filter_out_fn)
 295                 if not capture or len(capture.res) == 0:
 296                     # junk filtered out, we're good
 297                     return
 298             except:
 299                 pass
 300             self.generate_debug_aid("empty-assert")
 301             if remark:
 302                 raise AssertionError(
 303                     "Non-empty capture file present for interface %s (%s)" %
 304                     (self.name, remark))
 305             else:
 306                 raise AssertionError("Capture file present for interface %s" %
 307                                      self.name)
 308
 309     def wait_for_pg_stop(self):
 310         # wait till packet-generator is stopped
 311         # "show packet-generator" while it is still running gives this:
 312         # Name               Enabled        Count     Parameters
 313         # pcap0-sw_if_inde     Yes           64       limit 64, ...
 314         #
 315         # also have a 5-minute timeout just in case things go terribly wrong...
 316         deadline = time.time() + 300
 317         while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
 318             self._test.sleep(0.01)  # yield
 319             if time.time() > deadline:
 320                 self.test.logger.debug("Timeout waiting for pg to stop")
 321                 break
 322
 323     def wait_for_capture_file(self, timeout=1):
 324         """
 325         Wait until pcap capture file appears
 326
 327         :param timeout: How long to wait for the packet (default 1s)
 328
 329         :returns: True/False if the file is present or appears within timeout
 330         """
 331         self.wait_for_pg_stop()
 332         deadline = time.time() + timeout
 333         if not os.path.isfile(self.out_path):
 334             self.test.logger.debug("Waiting for capture file %s to appear, "
 335                                    "timeout is %ss" % (self.out_path, timeout))
 336         else:
 337             self.test.logger.debug("Capture file %s already exists" %
 338                                    self.out_path)
 339             return True
 340         while time.time() < deadline:
 341             if os.path.isfile(self.out_path):
 342                 break
 343             self._test.sleep(0)  # yield
 344         if os.path.isfile(self.out_path):
 345             self.test.logger.debug("Capture file appeared after %fs" %
 346                                    (time.time() - (deadline - timeout)))
 347         else:
 348             self.test.logger.debug("Timeout - capture file still nowhere")
 349             return False
 350         return True
 351
 352     def verify_enough_packet_data_in_pcap(self):
 353         """
 354         Check if enough data is available in file handled by internal pcap
 355         reader so that a whole packet can be read.
 356
 357         :returns: True if enough data present, else False
 358         """
 359         orig_pos = self._pcap_reader.f.tell()  # save file position
 360         enough_data = False
 361         # read packet header from pcap
 362         packet_header_size = 16
 363         caplen = None
 364         end_pos = None
 365         hdr = self._pcap_reader.f.read(packet_header_size)
 366         if len(hdr) == packet_header_size:
 367             # parse the capture length - caplen
 368             sec, usec, caplen, wirelen = struct.unpack(
 369                 self._pcap_reader.endian + "IIII", hdr)
 370             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 371             end_pos = self._pcap_reader.f.tell()  # get position at end
 372             if end_pos >= orig_pos + len(hdr) + caplen:
 373                 enough_data = True  # yay, we have enough data
 374         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 375         return enough_data
 376
 377     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 378         """
 379         Wait for next packet captured with a timeout
 380
 381         :param timeout: How long to wait for the packet
 382
 383         :returns: Captured packet if no packet arrived within timeout
 384         :raises Exception: if no packet arrives within timeout
 385         """
 386         deadline = time.time() + timeout
 387         if self._pcap_reader is None:
 388             if not self.wait_for_capture_file(timeout):
 389                 raise CaptureTimeoutError("Capture file %s did not appear "
 390                                           "within timeout" % self.out_path)
 391             while time.time() < deadline:
 392                 try:
 393                     self._pcap_reader = PcapReader(self.out_path)
 394                     break
 395                 except:
 396                     self.test.logger.debug(
 397                         "Exception in scapy.PcapReader(%s): %s" %
 398                         (self.out_path, format_exc()))
 399         if not self._pcap_reader:
 400             raise CaptureTimeoutError("Capture file %s did not appear within "
 401                                       "timeout" % self.out_path)
 402
 403         poll = False
 404         if timeout > 0:
 405             self.test.logger.debug("Waiting for packet")
 406         else:
 407             poll = True
 408             self.test.logger.debug("Polling for packet")
 409         while time.time() < deadline or poll:
 410             if not self.verify_enough_packet_data_in_pcap():
 411                 self._test.sleep(0)  # yield
 412                 poll = False
 413                 continue
 414             p = self._pcap_reader.recv()
 415             if p is not None:
 416                 if filter_out_fn is not None and filter_out_fn(p):
 417                     self.test.logger.debug(
 418                         "Packet received after %ss was filtered out" %
 419                         (time.time() - (deadline - timeout)))
 420                 else:
 421                     self.test.logger.debug(
 422                         "Packet received after %fs" %
 423                         (time.time() - (deadline - timeout)))
 424                     return p
 425             self._test.sleep(0)  # yield
 426             poll = False
 427         self.test.logger.debug("Timeout - no packets received")
 428         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 429
 430     def create_arp_req(self):
 431         """Create ARP request applicable for this interface"""
 432         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 433                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 434                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 435
 436     def create_ndp_req(self, addr=None):
 437         """Create NDP - NS applicable for this interface"""
 438         if not addr:
 439             addr = self.local_ip6
 440         nsma = in6_getnsma(inet_pton(socket.AF_INET6, addr))
 441         d = inet_ntop(socket.AF_INET6, nsma)
 442
 443         return (Ether(dst=in6_getnsmac(nsma)) /
 444                 IPv6(dst=d, src=self.remote_ip6) /
 445                 ICMPv6ND_NS(tgt=addr) /
 446                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 447
 448     def resolve_arp(self, pg_interface=None):
 449         """Resolve ARP using provided packet-generator interface
 450
 451         :param pg_interface: interface used to resolve, if None then this
 452             interface is used
 453
 454         """
 455         if pg_interface is None:
 456             pg_interface = self
 457         self.test.logger.info("Sending ARP request for %s on port %s" %
 458                               (self.local_ip4, pg_interface.name))
 459         arp_req = self.create_arp_req()
 460         pg_interface.add_stream(arp_req)
 461         pg_interface.enable_capture()
 462         self.test.pg_start()
 463         self.test.logger.info(self.test.vapi.cli("show trace"))
 464         try:
 465             captured_packet = pg_interface.wait_for_packet(1)
 466         except:
 467             self.test.logger.info("No ARP received on port %s" %
 468                                   pg_interface.name)
 469             return
 470         arp_reply = captured_packet.copy()  # keep original for exception
 471         try:
 472             if arp_reply[ARP].op == ARP.is_at:
 473                 self.test.logger.info("VPP %s MAC address is %s " %
 474                                       (self.name, arp_reply[ARP].hwsrc))
 475                 self._local_mac = arp_reply[ARP].hwsrc
 476             else:
 477                 self.test.logger.info("No ARP received on port %s" %
 478                                       pg_interface.name)
 479         except:
 480             self.test.logger.error(
 481                 ppp("Unexpected response to ARP request:", captured_packet))
 482             raise
 483
 484     def resolve_ndp(self, pg_interface=None, timeout=1, link_layer=False):
 485         """Resolve NDP using provided packet-generator interface
 486
 487         :param pg_interface: interface used to resolve, if None then this
 488             interface is used
 489         :param timeout: how long to wait for response before giving up
 490         :param link_layer: resolve for global address if False (default)
 491             or for link-layer address if True
 492
 493         """
 494         if pg_interface is None:
 495             pg_interface = self
 496         addr = self.local_ip6_ll if link_layer else self.local_ip6
 497         self.test.logger.info("Sending NDP request for %s on port %s" %
 498                               (addr, pg_interface.name))
 499         ndp_req = self.create_ndp_req(addr)
 500         pg_interface.add_stream(ndp_req)
 501         pg_interface.enable_capture()
 502         self.test.pg_start()
 503         now = time.time()
 504         deadline = now + timeout
 505         # Enabling IPv6 on an interface can generate more than the
 506         # ND reply we are looking for (namely MLD). So loop through
 507         # the replies to look for want we want.
 508         while now < deadline:
 509             try:
 510                 captured_packet = pg_interface.wait_for_packet(
 511                     deadline - now, filter_out_fn=None)
 512             except:
 513                 self.test.logger.error(
 514                     "Timeout while waiting for NDP response")
 515                 raise
 516             ndp_reply = captured_packet.copy()  # keep original for exception
 517             try:
 518                 ndp_na = ndp_reply[ICMPv6ND_NA]
 519                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 520                 self.test.logger.info("VPP %s MAC address is %s " %
 521                                       (self.name, opt.lladdr))
 522                 self._local_mac = opt.lladdr
 523                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 524                 # we now have the MAC we've been after
 525                 return
 526             except:
 527                 self.test.logger.info(
 528                     ppp("Unexpected response to NDP request:",
 529                         captured_packet))
 530             now = time.time()
 531
 532         self.test.logger.debug(self.test.vapi.cli("show trace"))
 533         raise Exception("Timeout while waiting for NDP response")