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     @property
  73     def in_path(self):
  74         """ pcap file path - injected packets"""
  75         return self._in_path
  76
  77     @property
  78     def capture_cli(self):
  79         """CLI string to start capture on this interface"""
  80         return self._capture_cli
  81
  82     @property
  83     def cap_name(self):
  84         """capture name for this interface"""
  85         return self._cap_name
  86
  87     @property
  88     def input_cli(self):
  89         """CLI string to load the injected packets"""
  90         if self._nb_replays is not None:
  91             return "%s limit %d" % (self._input_cli, self._nb_replays)
  92         if self._worker is not None:
  93             return "%s worker %d" % (self._input_cli, self._worker)
  94         return self._input_cli
  95
  96     @property
  97     def in_history_counter(self):
  98         """Self-incrementing counter used when renaming old pcap files"""
  99         v = self._in_history_counter
 100         self._in_history_counter += 1
 101         return v
 102
 103     @property
 104     def out_history_counter(self):
 105         """Self-incrementing counter used when renaming old pcap files"""
 106         v = self._out_history_counter
 107         self._out_history_counter += 1
 108         return v
 109
 110     def __init__(self, test, pg_index, gso, gso_size):
 111         """ Create VPP packet-generator interface """
 112         super(VppPGInterface, self).__init__(test)
 113
 114         r = test.vapi.pg_create_interface(pg_index, gso, gso_size)
 115         self.set_sw_if_index(r.sw_if_index)
 116
 117         self._in_history_counter = 0
 118         self._out_history_counter = 0
 119         self._out_assert_counter = 0
 120         self._pg_index = pg_index
 121         self._gso_enabled = gso
 122         self._gso_size = gso_size
 123         self._coalesce_enabled = 0
 124         self._out_file = "pg%u_out.pcap" % self.pg_index
 125         self._out_path = self.test.tempdir + "/" + self._out_file
 126         self._in_file = "pg%u_in.pcap" % self.pg_index
 127         self._in_path = self.test.tempdir + "/" + self._in_file
 128         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 129             self.pg_index, self.out_path)
 130         self._cap_name = "pcap%u-sw_if_index-%s" % (
 131             self.pg_index, self.sw_if_index)
 132         self._input_cli = \
 133             "packet-generator new pcap %s source pg%u name %s" % (
 134                 self.in_path, self.pg_index, self.cap_name)
 135         self._nb_replays = None
 136
 137     def _rename_previous_capture_file(self, path, counter, file):
 138         # if a file from a previous capture exists, rename it.
 139         try:
 140             if os.path.isfile(path):
 141                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 142                     (self.test.tempdir,
 143                      time.time(),
 144                      self.name,
 145                      counter,
 146                      file)
 147                 self.test.logger.debug("Renaming %s->%s" %
 148                                        (path, name))
 149                 os.rename(path, name)
 150         except OSError:
 151             self.test.logger.debug("OSError: Could not rename %s %s" %
 152                                    (path, file))
 153
 154     def enable_capture(self):
 155         """ Enable capture on this packet-generator interface
 156             of at most n packets.
 157             If n < 0, this is no limit
 158         """
 159         # disable the capture to flush the capture
 160         self.disable_capture()
 161         self._rename_previous_capture_file(self.out_path,
 162                                            self.out_history_counter,
 163                                            self._out_file)
 164         # FIXME this should be an API, but no such exists atm
 165         self.test.vapi.cli(self.capture_cli)
 166         self._pcap_reader = None
 167
 168     def disable_capture(self):
 169         self.test.vapi.cli("%s disable" % self.capture_cli)
 170
 171     def coalesce_enable(self):
 172         """ Enable packet coalesce on this packet-generator interface"""
 173         self._coalesce_enabled = 1
 174         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 175                                                             1)
 176
 177     def coalesce_disable(self):
 178         """ Disable packet coalesce on this packet-generator interface"""
 179         self._coalesce_enabled = 0
 180         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 181                                                             0)
 182
 183     def add_stream(self, pkts, nb_replays=None, worker=None):
 184         """
 185         Add a stream of packets to this packet-generator
 186
 187         :param pkts: iterable packets
 188
 189         """
 190         self._worker = worker
 191         self._nb_replays = nb_replays
 192         self._rename_previous_capture_file(self.in_path,
 193                                            self.in_history_counter,
 194                                            self._in_file)
 195         wrpcap(self.in_path, pkts)
 196         self.test.register_capture(self.cap_name)
 197         # FIXME this should be an API, but no such exists atm
 198         self.test.vapi.cli(self.input_cli)
 199
 200     def generate_debug_aid(self, kind):
 201         """ Create a hardlink to the out file with a counter and a file
 202         containing stack trace to ease debugging in case of multiple capture
 203         files present. """
 204         self.test.logger.debug("Generating debug aid for %s on %s" %
 205                                (kind, self._name))
 206         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 207                                  (self.test.tempdir, self._name,
 208                                   self._out_assert_counter, kind, suffix)
 209                                  for suffix in ["pcap", "stack"]
 210                                  ]
 211         os.link(self.out_path, link_path)
 212         with open(stack_path, "w") as f:
 213             f.writelines(format_stack())
 214         self._out_assert_counter += 1
 215
 216     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 217         """ Helper method to get capture and filter it """
 218         try:
 219             if not self.wait_for_capture_file(timeout):
 220                 return None
 221             output = rdpcap(self.out_path)
 222             self.test.logger.debug("Capture has %s packets" % len(output.res))
 223         except:
 224             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 225                                    (self.out_path, format_exc()))
 226             return None
 227         before = len(output.res)
 228         if filter_out_fn:
 229             output.res = [p for p in output.res if not filter_out_fn(p)]
 230         removed = before - len(output.res)
 231         if removed:
 232             self.test.logger.debug(
 233                 "Filtered out %s packets from capture (returning %s)" %
 234                 (removed, len(output.res)))
 235         return output
 236
 237     def get_capture(self, expected_count=None, remark=None, timeout=1,
 238                     filter_out_fn=is_ipv6_misc):
 239         """ Get captured packets
 240
 241         :param expected_count: expected number of packets to capture, if None,
 242                                then self.test.packet_count_for_dst_pg_idx is
 243                                used to lookup the expected count
 244         :param remark: remark printed into debug logs
 245         :param timeout: how long to wait for packets
 246         :param filter_out_fn: filter applied to each packet, packets for which
 247                               the filter returns True are removed from capture
 248         :returns: iterable packets
 249         """
 250         remaining_time = timeout
 251         capture = None
 252         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 253         based_on = "based on provided argument"
 254         if expected_count is None:
 255             expected_count = \
 256                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 257             based_on = "based on stored packet_infos"
 258             if expected_count == 0:
 259                 raise Exception(
 260                     "Internal error, expected packet count for %s is 0!" %
 261                     name)
 262         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 263             expected_count, based_on, name))
 264         while remaining_time > 0:
 265             before = time.time()
 266             capture = self._get_capture(remaining_time, filter_out_fn)
 267             elapsed_time = time.time() - before
 268             if capture:
 269                 if len(capture.res) == expected_count:
 270                     # bingo, got the packets we expected
 271                     return capture
 272                 elif len(capture.res) > expected_count:
 273                     self.test.logger.error(
 274                         ppc("Unexpected packets captured:", capture))
 275                     break
 276                 else:
 277                     self.test.logger.debug("Partial capture containing %s "
 278                                            "packets doesn't match expected "
 279                                            "count %s (yet?)" %
 280                                            (len(capture.res), expected_count))
 281             elif expected_count == 0:
 282                 # bingo, got None as we expected - return empty capture
 283                 return PacketList()
 284             remaining_time -= elapsed_time
 285         if capture:
 286             self.generate_debug_aid("count-mismatch")
 287             raise Exception("Captured packets mismatch, captured %s packets, "
 288                             "expected %s packets on %s" %
 289                             (len(capture.res), expected_count, name))
 290         else:
 291             raise Exception("No packets captured on %s" % name)
 292
 293     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 294         """ Assert that nothing unfiltered was captured on interface
 295
 296         :param remark: remark printed into debug logs
 297         :param filter_out_fn: filter applied to each packet, packets for which
 298                               the filter returns True are removed from capture
 299         """
 300         if os.path.isfile(self.out_path):
 301             try:
 302                 capture = self.get_capture(
 303                     0, remark=remark, filter_out_fn=filter_out_fn)
 304                 if not capture or len(capture.res) == 0:
 305                     # junk filtered out, we're good
 306                     return
 307             except:
 308                 pass
 309             self.generate_debug_aid("empty-assert")
 310             if remark:
 311                 raise AssertionError(
 312                     "Non-empty capture file present for interface %s (%s)" %
 313                     (self.name, remark))
 314             else:
 315                 raise AssertionError("Capture file present for interface %s" %
 316                                      self.name)
 317
 318     def wait_for_pg_stop(self):
 319         # wait till packet-generator is stopped
 320         # "show packet-generator" while it is still running gives this:
 321         # Name               Enabled        Count     Parameters
 322         # pcap0-sw_if_inde     Yes           64       limit 64, ...
 323         #
 324         # also have a 5-minute timeout just in case things go terribly wrong...
 325         deadline = time.time() + 300
 326         while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
 327             self._test.sleep(0.01)  # yield
 328             if time.time() > deadline:
 329                 self.test.logger.debug("Timeout waiting for pg to stop")
 330                 break
 331
 332     def wait_for_capture_file(self, timeout=1):
 333         """
 334         Wait until pcap capture file appears
 335
 336         :param timeout: How long to wait for the packet (default 1s)
 337
 338         :returns: True/False if the file is present or appears within timeout
 339         """
 340         self.wait_for_pg_stop()
 341         deadline = time.time() + timeout
 342         if not os.path.isfile(self.out_path):
 343             self.test.logger.debug("Waiting for capture file %s to appear, "
 344                                    "timeout is %ss" % (self.out_path, timeout))
 345         else:
 346             self.test.logger.debug("Capture file %s already exists" %
 347                                    self.out_path)
 348             return True
 349         while time.time() < deadline:
 350             if os.path.isfile(self.out_path):
 351                 break
 352             self._test.sleep(0)  # yield
 353         if os.path.isfile(self.out_path):
 354             self.test.logger.debug("Capture file appeared after %fs" %
 355                                    (time.time() - (deadline - timeout)))
 356         else:
 357             self.test.logger.debug("Timeout - capture file still nowhere")
 358             return False
 359         return True
 360
 361     def verify_enough_packet_data_in_pcap(self):
 362         """
 363         Check if enough data is available in file handled by internal pcap
 364         reader so that a whole packet can be read.
 365
 366         :returns: True if enough data present, else False
 367         """
 368         orig_pos = self._pcap_reader.f.tell()  # save file position
 369         enough_data = False
 370         # read packet header from pcap
 371         packet_header_size = 16
 372         caplen = None
 373         end_pos = None
 374         hdr = self._pcap_reader.f.read(packet_header_size)
 375         if len(hdr) == packet_header_size:
 376             # parse the capture length - caplen
 377             sec, usec, caplen, wirelen = struct.unpack(
 378                 self._pcap_reader.endian + "IIII", hdr)
 379             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 380             end_pos = self._pcap_reader.f.tell()  # get position at end
 381             if end_pos >= orig_pos + len(hdr) + caplen:
 382                 enough_data = True  # yay, we have enough data
 383         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 384         return enough_data
 385
 386     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 387         """
 388         Wait for next packet captured with a timeout
 389
 390         :param timeout: How long to wait for the packet
 391
 392         :returns: Captured packet if no packet arrived within timeout
 393         :raises Exception: if no packet arrives within timeout
 394         """
 395         deadline = time.time() + timeout
 396         if self._pcap_reader is None:
 397             if not self.wait_for_capture_file(timeout):
 398                 raise CaptureTimeoutError("Capture file %s did not appear "
 399                                           "within timeout" % self.out_path)
 400             while time.time() < deadline:
 401                 try:
 402                     self._pcap_reader = PcapReader(self.out_path)
 403                     break
 404                 except:
 405                     self.test.logger.debug(
 406                         "Exception in scapy.PcapReader(%s): %s" %
 407                         (self.out_path, format_exc()))
 408         if not self._pcap_reader:
 409             raise CaptureTimeoutError("Capture file %s did not appear within "
 410                                       "timeout" % self.out_path)
 411
 412         poll = False
 413         if timeout > 0:
 414             self.test.logger.debug("Waiting for packet")
 415         else:
 416             poll = True
 417             self.test.logger.debug("Polling for packet")
 418         while time.time() < deadline or poll:
 419             if not self.verify_enough_packet_data_in_pcap():
 420                 self._test.sleep(0)  # yield
 421                 poll = False
 422                 continue
 423             p = self._pcap_reader.recv()
 424             if p is not None:
 425                 if filter_out_fn is not None and filter_out_fn(p):
 426                     self.test.logger.debug(
 427                         "Packet received after %ss was filtered out" %
 428                         (time.time() - (deadline - timeout)))
 429                 else:
 430                     self.test.logger.debug(
 431                         "Packet received after %fs" %
 432                         (time.time() - (deadline - timeout)))
 433                     return p
 434             self._test.sleep(0)  # yield
 435             poll = False
 436         self.test.logger.debug("Timeout - no packets received")
 437         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 438
 439     def create_arp_req(self):
 440         """Create ARP request applicable for this interface"""
 441         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 442                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 443                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 444
 445     def create_ndp_req(self, addr=None):
 446         """Create NDP - NS applicable for this interface"""
 447         if not addr:
 448             addr = self.local_ip6
 449         nsma = in6_getnsma(inet_pton(socket.AF_INET6, addr))
 450         d = inet_ntop(socket.AF_INET6, nsma)
 451
 452         return (Ether(dst=in6_getnsmac(nsma)) /
 453                 IPv6(dst=d, src=self.remote_ip6) /
 454                 ICMPv6ND_NS(tgt=addr) /
 455                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 456
 457     def resolve_arp(self, pg_interface=None):
 458         """Resolve ARP using provided packet-generator interface
 459
 460         :param pg_interface: interface used to resolve, if None then this
 461             interface is used
 462
 463         """
 464         if pg_interface is None:
 465             pg_interface = self
 466         self.test.logger.info("Sending ARP request for %s on port %s" %
 467                               (self.local_ip4, pg_interface.name))
 468         arp_req = self.create_arp_req()
 469         pg_interface.add_stream(arp_req)
 470         pg_interface.enable_capture()
 471         self.test.pg_start()
 472         self.test.logger.info(self.test.vapi.cli("show trace"))
 473         try:
 474             captured_packet = pg_interface.wait_for_packet(1)
 475         except:
 476             self.test.logger.info("No ARP received on port %s" %
 477                                   pg_interface.name)
 478             return
 479         arp_reply = captured_packet.copy()  # keep original for exception
 480         try:
 481             if arp_reply[ARP].op == ARP.is_at:
 482                 self.test.logger.info("VPP %s MAC address is %s " %
 483                                       (self.name, arp_reply[ARP].hwsrc))
 484                 self._local_mac = arp_reply[ARP].hwsrc
 485             else:
 486                 self.test.logger.info("No ARP received on port %s" %
 487                                       pg_interface.name)
 488         except:
 489             self.test.logger.error(
 490                 ppp("Unexpected response to ARP request:", captured_packet))
 491             raise
 492
 493     def resolve_ndp(self, pg_interface=None, timeout=1, link_layer=False):
 494         """Resolve NDP using provided packet-generator interface
 495
 496         :param pg_interface: interface used to resolve, if None then this
 497             interface is used
 498         :param timeout: how long to wait for response before giving up
 499         :param link_layer: resolve for global address if False (default)
 500             or for link-layer address if True
 501
 502         """
 503         if pg_interface is None:
 504             pg_interface = self
 505         addr = self.local_ip6_ll if link_layer else self.local_ip6
 506         self.test.logger.info("Sending NDP request for %s on port %s" %
 507                               (addr, pg_interface.name))
 508         ndp_req = self.create_ndp_req(addr)
 509         pg_interface.add_stream(ndp_req)
 510         pg_interface.enable_capture()
 511         self.test.pg_start()
 512         now = time.time()
 513         deadline = now + timeout
 514         # Enabling IPv6 on an interface can generate more than the
 515         # ND reply we are looking for (namely MLD). So loop through
 516         # the replies to look for want we want.
 517         while now < deadline:
 518             try:
 519                 captured_packet = pg_interface.wait_for_packet(
 520                     deadline - now, filter_out_fn=None)
 521             except:
 522                 self.test.logger.error(
 523                     "Timeout while waiting for NDP response")
 524                 raise
 525             ndp_reply = captured_packet.copy()  # keep original for exception
 526             try:
 527                 ndp_na = ndp_reply[ICMPv6ND_NA]
 528                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 529                 self.test.logger.info("VPP %s MAC address is %s " %
 530                                       (self.name, opt.lladdr))
 531                 self._local_mac = opt.lladdr
 532                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 533                 # we now have the MAC we've been after
 534                 return
 535             except:
 536                 self.test.logger.info(
 537                     ppp("Unexpected response to NDP request:",
 538                         captured_packet))
 539             now = time.time()
 540
 541         self.test.logger.debug(self.test.vapi.cli("show trace"))
 542         raise Exception("Timeout while waiting for NDP response")