test/vpp_pg_interface.py

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