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