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