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