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 from config import config
   9 import scapy.compat
  10 from scapy.utils import wrpcap, rdpcap, PcapReader
  11 from scapy.plist import PacketList
  12 from vpp_interface import VppInterface
  13 from vpp_papi import VppEnum
  14
  15 from scapy.layers.l2 import Ether, ARP
  16 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
  17     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
  18     IPv6ExtHdrHopByHop
  19 from util import ppp, ppc, UnexpectedPacketError
  20 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  21
  22
  23 class CaptureTimeoutError(Exception):
  24     """ Exception raised if capture or packet doesn't appear within timeout """
  25     pass
  26
  27
  28 def is_ipv6_misc(p):
  29     """ Is packet one of uninteresting IPv6 broadcasts? """
  30     if p.haslayer(ICMPv6ND_RA):
  31         if in6_ismaddr(p[IPv6].dst):
  32             return True
  33     if p.haslayer(IPv6ExtHdrHopByHop):
  34         for o in p[IPv6ExtHdrHopByHop].options:
  35             if isinstance(o, RouterAlert):
  36                 return True
  37     return False
  38
  39
  40 class VppPGInterface(VppInterface):
  41     """
  42     VPP packet-generator interface
  43     """
  44
  45     @property
  46     def pg_index(self):
  47         """packet-generator interface index assigned by VPP"""
  48         return self._pg_index
  49
  50     @property
  51     def gso_enabled(self):
  52         """gso enabled on packet-generator interface"""
  53         if self._gso_enabled == 0:
  54             return "gso-disabled"
  55         return "gso-enabled"
  56
  57     @property
  58     def gso_size(self):
  59         """gso size on packet-generator interface"""
  60         return self._gso_size
  61
  62     @property
  63     def coalesce_is_enabled(self):
  64         """coalesce enabled on packet-generator interface"""
  65         if self._coalesce_enabled == 0:
  66             return "coalesce-disabled"
  67         return "coalesce-enabled"
  68
  69     @property
  70     def out_path(self):
  71         """pcap file path - captured packets"""
  72         return self._out_path
  73
  74     def get_in_path(self, worker):
  75         """ pcap file path - injected packets"""
  76         if worker is not None:
  77             return "%s/pg%u_wrk%u_in.pcap" % (self.test.tempdir, self.pg_index,
  78                                               worker)
  79         return "%s/pg%u_in.pcap" % (self.test.tempdir, self.pg_index)
  80
  81     @property
  82     def capture_cli(self):
  83         """CLI string to start capture on this interface"""
  84         return self._capture_cli
  85
  86     def get_cap_name(self, worker=None):
  87         """return capture name for this interface and given worker"""
  88         if worker is not None:
  89             return self._cap_name + "-worker%d" % worker
  90         return self._cap_name
  91
  92     def get_input_cli(self, nb_replays=None, worker=None):
  93         """return CLI string to load the injected packets"""
  94         input_cli = "packet-generator new pcap %s source pg%u name %s" % (
  95             self.get_in_path(worker), self.pg_index, self.get_cap_name(worker))
  96         if nb_replays is not None:
  97             return "%s limit %d" % (input_cli, nb_replays)
  98         if worker is not None:
  99             return "%s worker %d" % (input_cli, worker)
 100         return input_cli
 101
 102     @property
 103     def in_history_counter(self):
 104         """Self-incrementing counter used when renaming old pcap files"""
 105         v = self._in_history_counter
 106         self._in_history_counter += 1
 107         return v
 108
 109     @property
 110     def out_history_counter(self):
 111         """Self-incrementing counter used when renaming old pcap files"""
 112         v = self._out_history_counter
 113         self._out_history_counter += 1
 114         return v
 115
 116     def __init__(self, test, pg_index, gso, gso_size, mode):
 117         """ Create VPP packet-generator interface """
 118         super().__init__(test)
 119
 120         r = test.vapi.pg_create_interface_v2(pg_index, gso, gso_size, mode)
 121         self.set_sw_if_index(r.sw_if_index)
 122
 123         self._in_history_counter = 0
 124         self._out_history_counter = 0
 125         self._out_assert_counter = 0
 126         self._pg_index = pg_index
 127         self._gso_enabled = gso
 128         self._gso_size = gso_size
 129         self._coalesce_enabled = 0
 130         self._out_file = "pg%u_out.pcap" % self.pg_index
 131         self._out_path = self.test.tempdir + "/" + self._out_file
 132         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 133             self.pg_index, self.out_path)
 134         self._cap_name = "pcap%u-sw_if_index-%s" % (
 135             self.pg_index, self.sw_if_index)
 136
 137     def handle_old_pcap_file(self, path, counter):
 138         filename = os.path.basename(path)
 139
 140         if not config.keep_pcaps:
 141             try:
 142                 self.test.logger.debug(f"Removing {path}")
 143                 os.remove(path)
 144             except OSError:
 145                 self.test.logger.debug(f"OSError: Could not remove {path}")
 146             return
 147
 148         # keep
 149         try:
 150
 151             if os.path.isfile(path):
 152                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 153                     (self.test.tempdir,
 154                      time.time(),
 155                      self.name,
 156                      counter,
 157                      filename)
 158                 self.test.logger.debug("Renaming %s->%s" % (path, name))
 159                 os.rename(path, name)
 160         except OSError:
 161             self.test.logger.debug("OSError: Could not rename %s %s" %
 162                                    (path, filename))
 163
 164     def enable_capture(self):
 165         """ Enable capture on this packet-generator interface
 166             of at most n packets.
 167             If n < 0, this is no limit
 168         """
 169         # disable the capture to flush the capture
 170         self.disable_capture()
 171         self.handle_old_pcap_file(self.out_path, self.out_history_counter)
 172         # FIXME this should be an API, but no such exists atm
 173         self.test.vapi.cli(self.capture_cli)
 174         self._pcap_reader = None
 175
 176     def disable_capture(self):
 177         self.test.vapi.cli("%s disable" % self.capture_cli)
 178
 179     def coalesce_enable(self):
 180         """ Enable packet coalesce on this packet-generator interface"""
 181         self._coalesce_enabled = 1
 182         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 183                                                             1)
 184
 185     def coalesce_disable(self):
 186         """ Disable packet coalesce on this packet-generator interface"""
 187         self._coalesce_enabled = 0
 188         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index,
 189                                                             0)
 190
 191     def add_stream(self, pkts, nb_replays=None, worker=None):
 192         """
 193         Add a stream of packets to this packet-generator
 194
 195         :param pkts: iterable packets
 196
 197         """
 198         wrpcap(self.get_in_path(worker), pkts)
 199         self.test.register_pcap(self, worker)
 200         # FIXME this should be an API, but no such exists atm
 201         self.test.vapi.cli(self.get_input_cli(nb_replays, worker))
 202
 203     def generate_debug_aid(self, kind):
 204         """ Create a hardlink to the out file with a counter and a file
 205         containing stack trace to ease debugging in case of multiple capture
 206         files present. """
 207         self.test.logger.debug("Generating debug aid for %s on %s" %
 208                                (kind, self._name))
 209         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 210                                  (self.test.tempdir, self._name,
 211                                   self._out_assert_counter, kind, suffix)
 212                                  for suffix in ["pcap", "stack"]
 213                                  ]
 214         os.link(self.out_path, link_path)
 215         with open(stack_path, "w") as f:
 216             f.writelines(format_stack())
 217         self._out_assert_counter += 1
 218
 219     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 220         """ Helper method to get capture and filter it """
 221         try:
 222             if not self.wait_for_capture_file(timeout):
 223                 return None
 224             output = rdpcap(self.out_path)
 225             self.test.logger.debug("Capture has %s packets" % len(output.res))
 226         except:
 227             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 228                                    (self.out_path, format_exc()))
 229             return None
 230         before = len(output.res)
 231         if filter_out_fn:
 232             output.res = [p for p in output.res if not filter_out_fn(p)]
 233         removed = before - len(output.res)
 234         if removed:
 235             self.test.logger.debug(
 236                 "Filtered out %s packets from capture (returning %s)" %
 237                 (removed, len(output.res)))
 238         return output
 239
 240     def get_capture(self, expected_count=None, remark=None, timeout=1,
 241                     filter_out_fn=is_ipv6_misc):
 242         """ Get captured packets
 243
 244         :param expected_count: expected number of packets to capture, if None,
 245                                then self.test.packet_count_for_dst_pg_idx is
 246                                used to lookup the expected count
 247         :param remark: remark printed into debug logs
 248         :param timeout: how long to wait for packets
 249         :param filter_out_fn: filter applied to each packet, packets for which
 250                               the filter returns True are removed from capture
 251         :returns: iterable packets
 252         """
 253         remaining_time = timeout
 254         capture = None
 255         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 256         based_on = "based on provided argument"
 257         if expected_count is None:
 258             expected_count = \
 259                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 260             based_on = "based on stored packet_infos"
 261             if expected_count == 0:
 262                 raise Exception(
 263                     "Internal error, expected packet count for %s is 0!" %
 264                     name)
 265         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 266             expected_count, based_on, name))
 267         while remaining_time > 0:
 268             before = time.time()
 269             capture = self._get_capture(remaining_time, filter_out_fn)
 270             elapsed_time = time.time() - before
 271             if capture:
 272                 if len(capture.res) == expected_count:
 273                     # bingo, got the packets we expected
 274                     return capture
 275                 elif len(capture.res) > expected_count:
 276                     self.test.logger.error(
 277                         ppc("Unexpected packets captured:", capture))
 278                     break
 279                 else:
 280                     self.test.logger.debug("Partial capture containing %s "
 281                                            "packets doesn't match expected "
 282                                            "count %s (yet?)" %
 283                                            (len(capture.res), expected_count))
 284             elif expected_count == 0:
 285                 # bingo, got None as we expected - return empty capture
 286                 return PacketList()
 287             remaining_time -= elapsed_time
 288         if capture:
 289             self.generate_debug_aid("count-mismatch")
 290             if len(capture) > 0 and 0 == expected_count:
 291                 rem = f"\n{remark}" if remark else ""
 292                 raise UnexpectedPacketError(
 293                     capture[0],
 294                     f"\n({len(capture)} packets captured in total){rem}")
 295             raise Exception("Captured packets mismatch, captured %s packets, "
 296                             "expected %s packets on %s" %
 297                             (len(capture.res), expected_count, name))
 298         else:
 299             if 0 == expected_count:
 300                 return
 301             raise Exception("No packets captured on %s" % name)
 302
 303     def assert_nothing_captured(self, timeout=1, remark=None,
 304                                 filter_out_fn=is_ipv6_misc):
 305         """ Assert that nothing unfiltered was captured on interface
 306
 307         :param remark: remark printed into debug logs
 308         :param filter_out_fn: filter applied to each packet, packets for which
 309                               the filter returns True are removed from capture
 310         """
 311         capture = self.get_capture(0, timeout=timeout, remark=remark,
 312                                    filter_out_fn=filter_out_fn)
 313         if not capture or len(capture.res) == 0:
 314             # junk filtered out, we're good
 315             return
 316
 317     def wait_for_pg_stop(self):
 318         # wait till packet-generator is stopped
 319         # "show packet-generator" while it is still running gives this:
 320         # Name               Enabled        Count     Parameters
 321         # pcap0-sw_if_inde     Yes           64       limit 64, ...
 322         #
 323         # also have a 5-minute timeout just in case things go terribly wrong...
 324         deadline = time.time() + 300
 325         while self.test.vapi.cli('show packet-generator').find("Yes") != -1:
 326             self._test.sleep(0.01)  # yield
 327             if time.time() > deadline:
 328                 self.test.logger.debug("Timeout waiting for pg to stop")
 329                 break
 330
 331     def wait_for_capture_file(self, timeout=1):
 332         """
 333         Wait until pcap capture file appears
 334
 335         :param timeout: How long to wait for the packet (default 1s)
 336
 337         :returns: True/False if the file is present or appears within timeout
 338         """
 339         self.wait_for_pg_stop()
 340         deadline = time.time() + timeout
 341         if not os.path.isfile(self.out_path):
 342             self.test.logger.debug("Waiting for capture file %s to appear, "
 343                                    "timeout is %ss" % (self.out_path, timeout))
 344         else:
 345             self.test.logger.debug("Capture file %s already exists" %
 346                                    self.out_path)
 347             return True
 348         while time.time() < deadline:
 349             if os.path.isfile(self.out_path):
 350                 break
 351             self._test.sleep(0)  # yield
 352         if os.path.isfile(self.out_path):
 353             self.test.logger.debug("Capture file appeared after %fs" %
 354                                    (time.time() - (deadline - timeout)))
 355         else:
 356             self.test.logger.debug("Timeout - capture file still nowhere")
 357             return False
 358         return True
 359
 360     def verify_enough_packet_data_in_pcap(self):
 361         """
 362         Check if enough data is available in file handled by internal pcap
 363         reader so that a whole packet can be read.
 364
 365         :returns: True if enough data present, else False
 366         """
 367         orig_pos = self._pcap_reader.f.tell()  # save file position
 368         enough_data = False
 369         # read packet header from pcap
 370         packet_header_size = 16
 371         caplen = None
 372         end_pos = None
 373         hdr = self._pcap_reader.f.read(packet_header_size)
 374         if len(hdr) == packet_header_size:
 375             # parse the capture length - caplen
 376             sec, usec, caplen, wirelen = struct.unpack(
 377                 self._pcap_reader.endian + "IIII", hdr)
 378             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 379             end_pos = self._pcap_reader.f.tell()  # get position at end
 380             if end_pos >= orig_pos + len(hdr) + caplen:
 381                 enough_data = True  # yay, we have enough data
 382         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 383         return enough_data
 384
 385     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 386         """
 387         Wait for next packet captured with a timeout
 388
 389         :param timeout: How long to wait for the packet
 390
 391         :returns: Captured packet if no packet arrived within timeout
 392         :raises Exception: if no packet arrives within timeout
 393         """
 394         deadline = time.time() + timeout
 395         if self._pcap_reader is None:
 396             if not self.wait_for_capture_file(timeout):
 397                 raise CaptureTimeoutError("Capture file %s did not appear "
 398                                           "within timeout" % self.out_path)
 399             while time.time() < deadline:
 400                 try:
 401                     self._pcap_reader = PcapReader(self.out_path)
 402                     break
 403                 except:
 404                     self.test.logger.debug(
 405                         "Exception in scapy.PcapReader(%s): %s" %
 406                         (self.out_path, format_exc()))
 407         if not self._pcap_reader:
 408             raise CaptureTimeoutError("Capture file %s did not appear within "
 409                                       "timeout" % self.out_path)
 410
 411         poll = False
 412         if timeout > 0:
 413             self.test.logger.debug("Waiting for packet")
 414         else:
 415             poll = True
 416             self.test.logger.debug("Polling for packet")
 417         while time.time() < deadline or poll:
 418             if not self.verify_enough_packet_data_in_pcap():
 419                 self._test.sleep(0)  # yield
 420                 poll = False
 421                 continue
 422             p = self._pcap_reader.recv()
 423             if p is not None:
 424                 if filter_out_fn is not None and filter_out_fn(p):
 425                     self.test.logger.debug(
 426                         "Packet received after %ss was filtered out" %
 427                         (time.time() - (deadline - timeout)))
 428                 else:
 429                     self.test.logger.debug(
 430                         "Packet received after %fs" %
 431                         (time.time() - (deadline - timeout)))
 432                     return p
 433             self._test.sleep(0)  # yield
 434             poll = False
 435         self.test.logger.debug("Timeout - no packets received")
 436         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 437
 438     def create_arp_req(self):
 439         """Create ARP request applicable for this interface"""
 440         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 441                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 442                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 443
 444     def create_ndp_req(self, addr=None):
 445         """Create NDP - NS applicable for this interface"""
 446         if not addr:
 447             addr = self.local_ip6
 448         nsma = in6_getnsma(inet_pton(socket.AF_INET6, addr))
 449         d = inet_ntop(socket.AF_INET6, nsma)
 450
 451         return (Ether(dst=in6_getnsmac(nsma)) /
 452                 IPv6(dst=d, src=self.remote_ip6) /
 453                 ICMPv6ND_NS(tgt=addr) /
 454                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 455
 456     def resolve_arp(self, pg_interface=None):
 457         """Resolve ARP using provided packet-generator interface
 458
 459         :param pg_interface: interface used to resolve, if None then this
 460             interface is used
 461
 462         """
 463         if pg_interface is None:
 464             pg_interface = self
 465         self.test.logger.info("Sending ARP request for %s on port %s" %
 466                               (self.local_ip4, pg_interface.name))
 467         arp_req = self.create_arp_req()
 468         pg_interface.add_stream(arp_req)
 469         pg_interface.enable_capture()
 470         self.test.pg_start()
 471         self.test.logger.info(self.test.vapi.cli("show trace"))
 472         try:
 473             captured_packet = pg_interface.wait_for_packet(1)
 474         except:
 475             self.test.logger.info("No ARP received on port %s" %
 476                                   pg_interface.name)
 477             return
 478         arp_reply = captured_packet.copy()  # keep original for exception
 479         try:
 480             if arp_reply[ARP].op == ARP.is_at:
 481                 self.test.logger.info("VPP %s MAC address is %s " %
 482                                       (self.name, arp_reply[ARP].hwsrc))
 483                 self._local_mac = arp_reply[ARP].hwsrc
 484             else:
 485                 self.test.logger.info("No ARP received on port %s" %
 486                                       pg_interface.name)
 487         except:
 488             self.test.logger.error(
 489                 ppp("Unexpected response to ARP request:", captured_packet))
 490             raise
 491
 492     def resolve_ndp(self, pg_interface=None, timeout=1, link_layer=False):
 493         """Resolve NDP using provided packet-generator interface
 494
 495         :param pg_interface: interface used to resolve, if None then this
 496             interface is used
 497         :param timeout: how long to wait for response before giving up
 498         :param link_layer: resolve for global address if False (default)
 499             or for link-layer address if True
 500
 501         """
 502         if pg_interface is None:
 503             pg_interface = self
 504         addr = self.local_ip6_ll if link_layer else self.local_ip6
 505         self.test.logger.info("Sending NDP request for %s on port %s" %
 506                               (addr, pg_interface.name))
 507         ndp_req = self.create_ndp_req(addr)
 508         pg_interface.add_stream(ndp_req)
 509         pg_interface.enable_capture()
 510         self.test.pg_start()
 511         now = time.time()
 512         deadline = now + timeout
 513         # Enabling IPv6 on an interface can generate more than the
 514         # ND reply we are looking for (namely MLD). So loop through
 515         # the replies to look for want we want.
 516         while now < deadline:
 517             try:
 518                 captured_packet = pg_interface.wait_for_packet(
 519                     deadline - now, filter_out_fn=None)
 520             except:
 521                 self.test.logger.error(
 522                     "Timeout while waiting for NDP response")
 523                 raise
 524             ndp_reply = captured_packet.copy()  # keep original for exception
 525             try:
 526                 ndp_na = ndp_reply[ICMPv6ND_NA]
 527                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 528                 self.test.logger.info("VPP %s MAC address is %s " %
 529                                       (self.name, opt.lladdr))
 530                 self._local_mac = opt.lladdr
 531                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 532                 # we now have the MAC we've been after
 533                 return
 534             except:
 535                 self.test.logger.info(
 536                     ppp("Unexpected response to NDP request:",
 537                         captured_packet))
 538             now = time.time()
 539
 540         self.test.logger.debug(self.test.vapi.cli("show trace"))
 541         raise Exception("Timeout while waiting for NDP response")