test/vpp_pg_interface.py

   1 import os
   2 import shutil
   3 import socket
   4 from socket import inet_pton, inet_ntop
   5 import struct
   6 import time
   7 from traceback import format_exc, format_stack
   8
   9 from config import config
  10 import scapy.compat
  11 from scapy.utils import wrpcap, rdpcap, PcapReader
  12 from scapy.plist import PacketList
  13 from vpp_interface import VppInterface
  14 from vpp_papi import VppEnum
  15
  16 from scapy.layers.l2 import Ether, ARP
  17 from scapy.layers.inet6 import (
  18     IPv6,
  19     ICMPv6ND_NS,
  20     ICMPv6ND_NA,
  21     ICMPv6NDOptSrcLLAddr,
  22     ICMPv6NDOptDstLLAddr,
  23     ICMPv6ND_RA,
  24     RouterAlert,
  25     IPv6ExtHdrHopByHop,
  26 )
  27 from util import ppp, ppc, UnexpectedPacketError
  28 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  29
  30
  31 class CaptureTimeoutError(Exception):
  32     """Exception raised if capture or packet doesn't appear within timeout"""
  33
  34     pass
  35
  36
  37 def is_ipv6_misc(p):
  38     """Is packet one of uninteresting IPv6 broadcasts?"""
  39     if p.haslayer(ICMPv6ND_RA):
  40         if in6_ismaddr(p[IPv6].dst):
  41             return True
  42     if p.haslayer(IPv6ExtHdrHopByHop):
  43         for o in p[IPv6ExtHdrHopByHop].options:
  44             if isinstance(o, RouterAlert):
  45                 return True
  46     return False
  47
  48
  49 class VppPGInterface(VppInterface):
  50     """
  51     VPP packet-generator interface
  52     """
  53
  54     @property
  55     def pg_index(self):
  56         """packet-generator interface index assigned by VPP"""
  57         return self._pg_index
  58
  59     @property
  60     def gso_enabled(self):
  61         """gso enabled on packet-generator interface"""
  62         if self._gso_enabled == 0:
  63             return "gso-disabled"
  64         return "gso-enabled"
  65
  66     @property
  67     def gso_size(self):
  68         """gso size on packet-generator interface"""
  69         return self._gso_size
  70
  71     @property
  72     def coalesce_is_enabled(self):
  73         """coalesce enabled on packet-generator interface"""
  74         if self._coalesce_enabled == 0:
  75             return "coalesce-disabled"
  76         return "coalesce-enabled"
  77
  78     @property
  79     def out_path(self):
  80         """pcap file path - captured packets"""
  81         return self._out_path
  82
  83     def get_in_path(self, worker):
  84         """pcap file path - injected packets"""
  85         if worker is not None:
  86             return "%s/pg%u_wrk%u_in.pcap" % (self.test.tempdir, self.pg_index, worker)
  87         return "%s/pg%u_in.pcap" % (self.test.tempdir, self.pg_index)
  88
  89     @property
  90     def capture_cli(self):
  91         """CLI string to start capture on this interface"""
  92         return self._capture_cli
  93
  94     def get_cap_name(self, worker=None):
  95         """return capture name for this interface and given worker"""
  96         if worker is not None:
  97             return self._cap_name + "-worker%d" % worker
  98         return self._cap_name
  99
 100     def get_input_cli(self, nb_replays=None, worker=None):
 101         """return CLI string to load the injected packets"""
 102         input_cli = "packet-generator new pcap %s source pg%u name %s" % (
 103             self.get_in_path(worker),
 104             self.pg_index,
 105             self.get_cap_name(worker),
 106         )
 107         if nb_replays is not None:
 108             return "%s limit %d" % (input_cli, nb_replays)
 109         if worker is not None:
 110             return "%s worker %d" % (input_cli, worker)
 111         return input_cli
 112
 113     @property
 114     def in_history_counter(self):
 115         """Self-incrementing counter used when renaming old pcap files"""
 116         v = self._in_history_counter
 117         self._in_history_counter += 1
 118         return v
 119
 120     @property
 121     def out_history_counter(self):
 122         """Self-incrementing counter used when renaming old pcap files"""
 123         v = self._out_history_counter
 124         self._out_history_counter += 1
 125         return v
 126
 127     def __init__(self, test, pg_index, gso, gso_size, mode):
 128         """Create VPP packet-generator interface"""
 129         super().__init__(test)
 130
 131         r = test.vapi.pg_create_interface_v2(pg_index, gso, gso_size, mode)
 132         self.set_sw_if_index(r.sw_if_index)
 133
 134         self._in_history_counter = 0
 135         self._out_history_counter = 0
 136         self._out_assert_counter = 0
 137         self._pg_index = pg_index
 138         self._gso_enabled = gso
 139         self._gso_size = gso_size
 140         self._coalesce_enabled = 0
 141         self._out_file = "pg%u_out.pcap" % self.pg_index
 142         self._out_path = self.test.tempdir + "/" + self._out_file
 143         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 144             self.pg_index,
 145             self.out_path,
 146         )
 147         self._cap_name = "pcap%u-sw_if_index-%s" % (self.pg_index, self.sw_if_index)
 148
 149     def handle_old_pcap_file(self, path, counter):
 150         filename = os.path.basename(path)
 151
 152         if not config.keep_pcaps:
 153             try:
 154                 self.test.logger.debug(f"Removing {path}")
 155                 os.remove(path)
 156             except OSError:
 157                 self.test.logger.debug(f"OSError: Could not remove {path}")
 158             return
 159
 160         # keep
 161         try:
 162
 163             if os.path.isfile(path):
 164                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % (
 165                     self.test.tempdir,
 166                     time.time(),
 167                     self.name,
 168                     counter,
 169                     filename,
 170                 )
 171                 self.test.logger.debug("Renaming %s->%s" % (path, name))
 172                 shutil.move(path, name)
 173         except OSError:
 174             self.test.logger.debug("OSError: Could not rename %s %s" % (path, filename))
 175
 176     def enable_capture(self):
 177         """Enable capture on this packet-generator interface
 178         of at most n packets.
 179         If n < 0, this is no limit
 180         """
 181         # disable the capture to flush the capture
 182         self.disable_capture()
 183         self.handle_old_pcap_file(self.out_path, self.out_history_counter)
 184         # FIXME this should be an API, but no such exists atm
 185         self.test.vapi.cli(self.capture_cli)
 186         self._pcap_reader = None
 187
 188     def disable_capture(self):
 189         self.test.vapi.cli("%s disable" % self.capture_cli)
 190
 191     def coalesce_enable(self):
 192         """Enable packet coalesce on this packet-generator interface"""
 193         self._coalesce_enabled = 1
 194         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index, 1)
 195
 196     def coalesce_disable(self):
 197         """Disable packet coalesce on this packet-generator interface"""
 198         self._coalesce_enabled = 0
 199         self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index, 0)
 200
 201     def add_stream(self, pkts, nb_replays=None, worker=None):
 202         """
 203         Add a stream of packets to this packet-generator
 204
 205         :param pkts: iterable packets
 206
 207         """
 208         wrpcap(self.get_in_path(worker), pkts)
 209         self.test.register_pcap(self, worker)
 210         # FIXME this should be an API, but no such exists atm
 211         self.test.vapi.cli(self.get_input_cli(nb_replays, worker))
 212
 213     def generate_debug_aid(self, kind):
 214         """Create a hardlink to the out file with a counter and a file
 215         containing stack trace to ease debugging in case of multiple capture
 216         files present."""
 217         self.test.logger.debug("Generating debug aid for %s on %s" % (kind, self._name))
 218         link_path, stack_path = [
 219             "%s/debug_%s_%s_%s.%s"
 220             % (self.test.tempdir, self._name, self._out_assert_counter, kind, suffix)
 221             for suffix in ["pcap", "stack"]
 222         ]
 223         os.link(self.out_path, link_path)
 224         with open(stack_path, "w") as f:
 225             f.writelines(format_stack())
 226         self._out_assert_counter += 1
 227
 228     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 229         """Helper method to get capture and filter it"""
 230         try:
 231             if not self.wait_for_capture_file(timeout):
 232                 return None
 233             output = rdpcap(self.out_path)
 234             self.test.logger.debug("Capture has %s packets" % len(output.res))
 235         except:
 236             self.test.logger.debug(
 237                 "Exception in scapy.rdpcap (%s): %s" % (self.out_path, format_exc())
 238             )
 239             return None
 240         before = len(output.res)
 241         if filter_out_fn:
 242             output.res = [p for p in output.res if not filter_out_fn(p)]
 243         removed = before - len(output.res)
 244         if removed:
 245             self.test.logger.debug(
 246                 "Filtered out %s packets from capture (returning %s)"
 247                 % (removed, len(output.res))
 248             )
 249         return output
 250
 251     def get_capture(
 252         self, expected_count=None, remark=None, timeout=1, filter_out_fn=is_ipv6_misc
 253     ):
 254         """Get captured packets
 255
 256         :param expected_count: expected number of packets to capture, if None,
 257                                then self.test.packet_count_for_dst_pg_idx is
 258                                used to lookup the expected count
 259         :param remark: remark printed into debug logs
 260         :param timeout: how long to wait for packets
 261         :param filter_out_fn: filter applied to each packet, packets for which
 262                               the filter returns True are removed from capture
 263         :returns: iterable packets
 264         """
 265         remaining_time = timeout
 266         capture = None
 267         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 268         based_on = "based on provided argument"
 269         if expected_count is None:
 270             expected_count = self.test.get_packet_count_for_if_idx(self.sw_if_index)
 271             based_on = "based on stored packet_infos"
 272             if expected_count == 0:
 273                 raise Exception(
 274                     "Internal error, expected packet count for %s is 0!" % name
 275                 )
 276         self.test.logger.debug(
 277             "Expecting to capture %s (%s) packets on %s"
 278             % (expected_count, based_on, name)
 279         )
 280         while remaining_time > 0:
 281             before = time.time()
 282             capture = self._get_capture(remaining_time, filter_out_fn)
 283             elapsed_time = time.time() - before
 284             if capture:
 285                 if len(capture.res) == expected_count:
 286                     # bingo, got the packets we expected
 287                     return capture
 288                 elif len(capture.res) > expected_count:
 289                     self.test.logger.error(ppc("Unexpected packets captured:", capture))
 290                     break
 291                 else:
 292                     self.test.logger.debug(
 293                         "Partial capture containing %s "
 294                         "packets doesn't match expected "
 295                         "count %s (yet?)" % (len(capture.res), expected_count)
 296                     )
 297             elif expected_count == 0:
 298                 # bingo, got None as we expected - return empty capture
 299                 return PacketList()
 300             remaining_time -= elapsed_time
 301         if capture:
 302             self.generate_debug_aid("count-mismatch")
 303             if len(capture) > 0 and 0 == expected_count:
 304                 rem = f"\n{remark}" if remark else ""
 305                 raise UnexpectedPacketError(
 306                     capture[0], f"\n({len(capture)} packets captured in total){rem}"
 307                 )
 308             raise Exception(
 309                 "Captured packets mismatch, captured %s packets, "
 310                 "expected %s packets on %s" % (len(capture.res), expected_count, name)
 311             )
 312         else:
 313             if 0 == expected_count:
 314                 return
 315             raise Exception("No packets captured on %s" % name)
 316
 317     def assert_nothing_captured(
 318         self, timeout=1, remark=None, filter_out_fn=is_ipv6_misc
 319     ):
 320         """Assert that nothing unfiltered was captured on interface
 321
 322         :param remark: remark printed into debug logs
 323         :param filter_out_fn: filter applied to each packet, packets for which
 324                               the filter returns True are removed from capture
 325         """
 326         capture = self.get_capture(
 327             0, timeout=timeout, remark=remark, filter_out_fn=filter_out_fn
 328         )
 329         if not capture or len(capture.res) == 0:
 330             # junk filtered out, we're good
 331             return
 332
 333     def wait_for_pg_stop(self):
 334         # wait till packet-generator is stopped
 335         # "show packet-generator" while it is still running gives this:
 336         # Name               Enabled        Count     Parameters
 337         # pcap0-sw_if_inde     Yes           64       limit 64, ...
 338         #
 339         # also have a 5-minute timeout just in case things go terribly wrong...
 340         deadline = time.time() + 300
 341         while self.test.vapi.cli("show packet-generator").find("Yes") != -1:
 342             self._test.sleep(0.01)  # yield
 343             if time.time() > deadline:
 344                 self.test.logger.debug("Timeout waiting for pg to stop")
 345                 break
 346
 347     def wait_for_capture_file(self, timeout=1):
 348         """
 349         Wait until pcap capture file appears
 350
 351         :param timeout: How long to wait for the packet (default 1s)
 352
 353         :returns: True/False if the file is present or appears within timeout
 354         """
 355         self.wait_for_pg_stop()
 356         deadline = time.time() + timeout
 357         if not os.path.isfile(self.out_path):
 358             self.test.logger.debug(
 359                 "Waiting for capture file %s to appear, "
 360                 "timeout is %ss" % (self.out_path, timeout)
 361             )
 362         else:
 363             self.test.logger.debug("Capture file %s already exists" % self.out_path)
 364             return True
 365         while time.time() < deadline:
 366             if os.path.isfile(self.out_path):
 367                 break
 368             self._test.sleep(0)  # yield
 369         if os.path.isfile(self.out_path):
 370             self.test.logger.debug(
 371                 "Capture file appeared after %fs" % (time.time() - (deadline - timeout))
 372             )
 373         else:
 374             self.test.logger.debug("Timeout - capture file still nowhere")
 375             return False
 376         return True
 377
 378     def verify_enough_packet_data_in_pcap(self):
 379         """
 380         Check if enough data is available in file handled by internal pcap
 381         reader so that a whole packet can be read.
 382
 383         :returns: True if enough data present, else False
 384         """
 385         orig_pos = self._pcap_reader.f.tell()  # save file position
 386         enough_data = False
 387         # read packet header from pcap
 388         packet_header_size = 16
 389         caplen = None
 390         end_pos = None
 391         hdr = self._pcap_reader.f.read(packet_header_size)
 392         if len(hdr) == packet_header_size:
 393             # parse the capture length - caplen
 394             sec, usec, caplen, wirelen = struct.unpack(
 395                 self._pcap_reader.endian + "IIII", hdr
 396             )
 397             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 398             end_pos = self._pcap_reader.f.tell()  # get position at end
 399             if end_pos >= orig_pos + len(hdr) + caplen:
 400                 enough_data = True  # yay, we have enough data
 401         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 402         return enough_data
 403
 404     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 405         """
 406         Wait for next packet captured with a timeout
 407
 408         :param timeout: How long to wait for the packet
 409
 410         :returns: Captured packet if no packet arrived within timeout
 411         :raises Exception: if no packet arrives within timeout
 412         """
 413         deadline = time.time() + timeout
 414         if self._pcap_reader is None:
 415             if not self.wait_for_capture_file(timeout):
 416                 raise CaptureTimeoutError(
 417                     "Capture file %s did not appear within timeout" % self.out_path
 418                 )
 419             while time.time() < deadline:
 420                 try:
 421                     self._pcap_reader = PcapReader(self.out_path)
 422                     break
 423                 except:
 424                     self.test.logger.debug(
 425                         "Exception in scapy.PcapReader(%s): %s"
 426                         % (self.out_path, format_exc())
 427                     )
 428         if not self._pcap_reader:
 429             raise CaptureTimeoutError(
 430                 "Capture file %s did not appear within timeout" % self.out_path
 431             )
 432
 433         poll = False
 434         if timeout > 0:
 435             self.test.logger.debug("Waiting for packet")
 436         else:
 437             poll = True
 438             self.test.logger.debug("Polling for packet")
 439         while time.time() < deadline or poll:
 440             if not self.verify_enough_packet_data_in_pcap():
 441                 self._test.sleep(0)  # yield
 442                 poll = False
 443                 continue
 444             p = self._pcap_reader.recv()
 445             if p is not None:
 446                 if filter_out_fn is not None and filter_out_fn(p):
 447                     self.test.logger.debug(
 448                         "Packet received after %ss was filtered out"
 449                         % (time.time() - (deadline - timeout))
 450                     )
 451                 else:
 452                     self.test.logger.debug(
 453                         "Packet received after %fs"
 454                         % (time.time() - (deadline - timeout))
 455                     )
 456                     return p
 457             self._test.sleep(0)  # yield
 458             poll = False
 459         self.test.logger.debug("Timeout - no packets received")
 460         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 461
 462     def create_arp_req(self):
 463         """Create ARP request applicable for this interface"""
 464         return Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) / ARP(
 465             op=ARP.who_has,
 466             pdst=self.local_ip4,
 467             psrc=self.remote_ip4,
 468             hwsrc=self.remote_mac,
 469         )
 470
 471     def create_ndp_req(self, addr=None):
 472         """Create NDP - NS applicable for this interface"""
 473         if not addr:
 474             addr = self.local_ip6
 475         nsma = in6_getnsma(inet_pton(socket.AF_INET6, addr))
 476         d = inet_ntop(socket.AF_INET6, nsma)
 477
 478         return (
 479             Ether(dst=in6_getnsmac(nsma))
 480             / IPv6(dst=d, src=self.remote_ip6)
 481             / ICMPv6ND_NS(tgt=addr)
 482             / ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac)
 483         )
 484
 485     def resolve_arp(self, pg_interface=None):
 486         """Resolve ARP using provided packet-generator interface
 487
 488         :param pg_interface: interface used to resolve, if None then this
 489             interface is used
 490
 491         """
 492         if pg_interface is None:
 493             pg_interface = self
 494         self.test.logger.info(
 495             "Sending ARP request for %s on port %s"
 496             % (self.local_ip4, pg_interface.name)
 497         )
 498         arp_req = self.create_arp_req()
 499         pg_interface.add_stream(arp_req)
 500         pg_interface.enable_capture()
 501         self.test.pg_start()
 502         self.test.logger.info(self.test.vapi.cli("show trace"))
 503         try:
 504             captured_packet = pg_interface.wait_for_packet(1)
 505         except:
 506             self.test.logger.info("No ARP received on port %s" % pg_interface.name)
 507             return
 508         arp_reply = captured_packet.copy()  # keep original for exception
 509         try:
 510             if arp_reply[ARP].op == ARP.is_at:
 511                 self.test.logger.info(
 512                     "VPP %s MAC address is %s " % (self.name, arp_reply[ARP].hwsrc)
 513                 )
 514                 self._local_mac = arp_reply[ARP].hwsrc
 515             else:
 516                 self.test.logger.info("No ARP received on port %s" % pg_interface.name)
 517         except:
 518             self.test.logger.error(
 519                 ppp("Unexpected response to ARP request:", captured_packet)
 520             )
 521             raise
 522
 523     def resolve_ndp(self, pg_interface=None, timeout=1, link_layer=False):
 524         """Resolve NDP using provided packet-generator interface
 525
 526         :param pg_interface: interface used to resolve, if None then this
 527             interface is used
 528         :param timeout: how long to wait for response before giving up
 529         :param link_layer: resolve for global address if False (default)
 530             or for link-layer address if True
 531
 532         """
 533         if pg_interface is None:
 534             pg_interface = self
 535         addr = self.local_ip6_ll if link_layer else self.local_ip6
 536         self.test.logger.info(
 537             "Sending NDP request for %s on port %s" % (addr, pg_interface.name)
 538         )
 539         ndp_req = self.create_ndp_req(addr)
 540         pg_interface.add_stream(ndp_req)
 541         pg_interface.enable_capture()
 542         self.test.pg_start()
 543         now = time.time()
 544         deadline = now + timeout
 545         # Enabling IPv6 on an interface can generate more than the
 546         # ND reply we are looking for (namely MLD). So loop through
 547         # the replies to look for want we want.
 548         while now < deadline:
 549             try:
 550                 captured_packet = pg_interface.wait_for_packet(
 551                     deadline - now, filter_out_fn=None
 552                 )
 553             except:
 554                 self.test.logger.error("Timeout while waiting for NDP response")
 555                 raise
 556             ndp_reply = captured_packet.copy()  # keep original for exception
 557             try:
 558                 ndp_na = ndp_reply[ICMPv6ND_NA]
 559                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 560                 self.test.logger.info(
 561                     "VPP %s MAC address is %s " % (self.name, opt.lladdr)
 562                 )
 563                 self._local_mac = opt.lladdr
 564                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 565                 # we now have the MAC we've been after
 566                 return
 567             except:
 568                 self.test.logger.info(
 569                     ppp("Unexpected response to NDP request:", captured_packet)
 570                 )
 571             now = time.time()
 572
 573         self.test.logger.debug(self.test.vapi.cli("show trace"))
 574         raise Exception("Timeout while waiting for NDP response")