test/vpp_pg_interface.py

   1 import os
   2 import time
   3 import socket
   4 from traceback import format_exc, format_stack
   5 from scapy.utils import wrpcap, rdpcap, PcapReader
   6 from scapy.plist import PacketList
   7 from vpp_interface import VppInterface
   8
   9 from scapy.layers.l2 import Ether, ARP
  10 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
  11     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
  12     IPv6ExtHdrHopByHop
  13 from util import ppp, ppc
  14 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  15 from scapy.utils import inet_pton, inet_ntop
  16
  17
  18 def is_ipv6_misc(p):
  19     """ Is packet one of uninteresting IPv6 broadcasts? """
  20     if p.haslayer(ICMPv6ND_RA):
  21         if in6_ismaddr(p[IPv6].dst):
  22             return True
  23     if p.haslayer(IPv6ExtHdrHopByHop):
  24         for o in p[IPv6ExtHdrHopByHop].options:
  25             if isinstance(o, RouterAlert):
  26                 return True
  27     return False
  28
  29
  30 class VppPGInterface(VppInterface):
  31     """
  32     VPP packet-generator interface
  33     """
  34
  35     @property
  36     def pg_index(self):
  37         """packet-generator interface index assigned by VPP"""
  38         return self._pg_index
  39
  40     @property
  41     def out_path(self):
  42         """pcap file path - captured packets"""
  43         return self._out_path
  44
  45     @property
  46     def in_path(self):
  47         """ pcap file path - injected packets"""
  48         return self._in_path
  49
  50     @property
  51     def capture_cli(self):
  52         """CLI string to start capture on this interface"""
  53         return self._capture_cli
  54
  55     @property
  56     def cap_name(self):
  57         """capture name for this interface"""
  58         return self._cap_name
  59
  60     @property
  61     def input_cli(self):
  62         """CLI string to load the injected packets"""
  63         return self._input_cli
  64
  65     @property
  66     def in_history_counter(self):
  67         """Self-incrementing counter used when renaming old pcap files"""
  68         v = self._in_history_counter
  69         self._in_history_counter += 1
  70         return v
  71
  72     @property
  73     def out_history_counter(self):
  74         """Self-incrementing counter used when renaming old pcap files"""
  75         v = self._out_history_counter
  76         self._out_history_counter += 1
  77         return v
  78
  79     def __init__(self, test, pg_index):
  80         """ Create VPP packet-generator interface """
  81         r = test.vapi.pg_create_interface(pg_index)
  82         self._sw_if_index = r.sw_if_index
  83
  84         super(VppPGInterface, self).__init__(test)
  85
  86         self._in_history_counter = 0
  87         self._out_history_counter = 0
  88         self._out_assert_counter = 0
  89         self._pg_index = pg_index
  90         self._out_file = "pg%u_out.pcap" % self.pg_index
  91         self._out_path = self.test.tempdir + "/" + self._out_file
  92         self._in_file = "pg%u_in.pcap" % self.pg_index
  93         self._in_path = self.test.tempdir + "/" + self._in_file
  94         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
  95             self.pg_index, self.out_path)
  96         self._cap_name = "pcap%u" % self.sw_if_index
  97         self._input_cli = \
  98             "packet-generator new pcap %s source pg%u name %s" % (
  99                 self.in_path, self.pg_index, self.cap_name)
 100
 101     def enable_capture(self):
 102         """ Enable capture on this packet-generator interface"""
 103         try:
 104             if os.path.isfile(self.out_path):
 105                 os.rename(self.out_path,
 106                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 107                           (self.test.tempdir,
 108                            time.time(),
 109                            self.name,
 110                            self.out_history_counter,
 111                            self._out_file))
 112         except:
 113             pass
 114         # FIXME this should be an API, but no such exists atm
 115         self.test.vapi.cli(self.capture_cli)
 116         self._pcap_reader = None
 117
 118     def add_stream(self, pkts):
 119         """
 120         Add a stream of packets to this packet-generator
 121
 122         :param pkts: iterable packets
 123
 124         """
 125         try:
 126             if os.path.isfile(self.in_path):
 127                 os.rename(self.in_path,
 128                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 129                           (self.test.tempdir,
 130                            time.time(),
 131                            self.name,
 132                            self.in_history_counter,
 133                            self._in_file))
 134         except:
 135             pass
 136         wrpcap(self.in_path, pkts)
 137         self.test.register_capture(self.cap_name)
 138         # FIXME this should be an API, but no such exists atm
 139         self.test.vapi.cli(self.input_cli)
 140
 141     def generate_debug_aid(self, kind):
 142         """ Create a hardlink to the out file with a counter and a file
 143         containing stack trace to ease debugging in case of multiple capture
 144         files present. """
 145         self.test.logger.debug("Generating debug aid for %s on %s" %
 146                                (kind, self._name))
 147         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 148                                  (self.test.tempdir, self._name,
 149                                   self._out_assert_counter, kind, suffix)
 150                                  for suffix in ["pcap", "stack"]
 151                                  ]
 152         os.link(self.out_path, link_path)
 153         with open(stack_path, "w") as f:
 154             f.writelines(format_stack())
 155         self._out_assert_counter += 1
 156
 157     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 158         """ Helper method to get capture and filter it """
 159         try:
 160             if not self.wait_for_capture_file(timeout):
 161                 return None
 162             output = rdpcap(self.out_path)
 163             self.test.logger.debug("Capture has %s packets" % len(output.res))
 164         except:
 165             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 166                                    (self.out_path, format_exc()))
 167             return None
 168         before = len(output.res)
 169         if filter_out_fn:
 170             output.res = [p for p in output.res if not filter_out_fn(p)]
 171         removed = before - len(output.res)
 172         if removed:
 173             self.test.logger.debug(
 174                 "Filtered out %s packets from capture (returning %s)" %
 175                 (removed, len(output.res)))
 176         return output
 177
 178     def get_capture(self, expected_count=None, remark=None, timeout=1,
 179                     filter_out_fn=is_ipv6_misc):
 180         """ Get captured packets
 181
 182         :param expected_count: expected number of packets to capture, if None,
 183                                then self.test.packet_count_for_dst_pg_idx is
 184                                used to lookup the expected count
 185         :param remark: remark printed into debug logs
 186         :param timeout: how long to wait for packets
 187         :param filter_out_fn: filter applied to each packet, packets for which
 188                               the filter returns True are removed from capture
 189         :returns: iterable packets
 190         """
 191         remaining_time = timeout
 192         capture = None
 193         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 194         based_on = "based on provided argument"
 195         if expected_count is None:
 196             expected_count = \
 197                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 198             based_on = "based on stored packet_infos"
 199             if expected_count == 0:
 200                 raise Exception(
 201                     "Internal error, expected packet count for %s is 0!" %
 202                     name)
 203         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 204             expected_count, based_on, name))
 205         while remaining_time > 0:
 206             before = time.time()
 207             capture = self._get_capture(remaining_time, filter_out_fn)
 208             elapsed_time = time.time() - before
 209             if capture:
 210                 if len(capture.res) == expected_count:
 211                     # bingo, got the packets we expected
 212                     return capture
 213                 else:
 214                     self.test.logger.debug("Partial capture containing %s "
 215                                            "packets doesn't match expected "
 216                                            "count %s (yet?)" %
 217                                            (len(capture.res), expected_count))
 218             elif expected_count == 0:
 219                 # bingo, got None as we expected - return empty capture
 220                 return PacketList()
 221             remaining_time -= elapsed_time
 222         if capture:
 223             self.generate_debug_aid("count-mismatch")
 224             raise Exception("Captured packets mismatch, captured %s packets, "
 225                             "expected %s packets on %s" %
 226                             (len(capture.res), expected_count, name))
 227         else:
 228             raise Exception("No packets captured on %s" % name)
 229
 230     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 231         """ Assert that nothing unfiltered was captured on interface
 232
 233         :param remark: remark printed into debug logs
 234         :param filter_out_fn: filter applied to each packet, packets for which
 235                               the filter returns True are removed from capture
 236         """
 237         if os.path.isfile(self.out_path):
 238             try:
 239                 capture = self.get_capture(
 240                     0, remark=remark, filter_out_fn=filter_out_fn)
 241                 if not capture or len(capture.res) == 0:
 242                     # junk filtered out, we're good
 243                     return
 244                 self.test.logger.error(
 245                     ppc("Unexpected packets captured:", capture))
 246             except:
 247                 pass
 248             self.generate_debug_aid("empty-assert")
 249             if remark:
 250                 raise AssertionError(
 251                     "Non-empty capture file present for interface %s (%s)" %
 252                     (self.name, remark))
 253             else:
 254                 raise AssertionError("Capture file present for interface %s" %
 255                                      self.name)
 256
 257     def wait_for_capture_file(self, timeout=1):
 258         """
 259         Wait until pcap capture file appears
 260
 261         :param timeout: How long to wait for the packet (default 1s)
 262
 263         :returns: True/False if the file is present or appears within timeout
 264         """
 265         limit = time.time() + timeout
 266         if not os.path.isfile(self.out_path):
 267             self.test.logger.debug("Waiting for capture file %s to appear, "
 268                                    "timeout is %ss" % (self.out_path, timeout))
 269         else:
 270             self.test.logger.debug(
 271                 "Capture file %s already exists" %
 272                 self.out_path)
 273             return True
 274         while time.time() < limit:
 275             if os.path.isfile(self.out_path):
 276                 break
 277             time.sleep(0)  # yield
 278         if os.path.isfile(self.out_path):
 279             self.test.logger.debug("Capture file appeared after %fs" %
 280                                    (time.time() - (limit - timeout)))
 281         else:
 282             self.test.logger.debug("Timeout - capture file still nowhere")
 283             return False
 284         return True
 285
 286     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 287         """
 288         Wait for next packet captured with a timeout
 289
 290         :param timeout: How long to wait for the packet
 291
 292         :returns: Captured packet if no packet arrived within timeout
 293         :raises Exception: if no packet arrives within timeout
 294         """
 295         deadline = time.time() + timeout
 296         if self._pcap_reader is None:
 297             if not self.wait_for_capture_file(timeout):
 298                 raise Exception("Capture file %s did not appear within "
 299                                 "timeout" % self.out_path)
 300             while time.time() < deadline:
 301                 try:
 302                     self._pcap_reader = PcapReader(self.out_path)
 303                     break
 304                 except:
 305                     self.test.logger.debug(
 306                         "Exception in scapy.PcapReader(%s): %s" %
 307                         (self.out_path, format_exc()))
 308         if not self._pcap_reader:
 309             raise Exception("Capture file %s did not appear within "
 310                             "timeout" % self.out_path)
 311
 312         self.test.logger.debug("Waiting for packet")
 313         while time.time() < deadline:
 314             p = self._pcap_reader.recv()
 315             if p is not None:
 316                 if filter_out_fn is not None and filter_out_fn(p):
 317                     self.test.logger.debug(
 318                         "Packet received after %ss was filtered out" %
 319                         (time.time() - (deadline - timeout)))
 320                 else:
 321                     self.test.logger.debug(
 322                         "Packet received after %fs" %
 323                         (time.time() - (deadline - timeout)))
 324                     return p
 325             time.sleep(0)  # yield
 326         self.test.logger.debug("Timeout - no packets received")
 327         raise Exception("Packet didn't arrive within timeout")
 328
 329     def create_arp_req(self):
 330         """Create ARP request applicable for this interface"""
 331         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 332                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 333                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 334
 335     def create_ndp_req(self):
 336         """Create NDP - NS applicable for this interface"""
 337         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 338         d = inet_ntop(socket.AF_INET6, nsma)
 339
 340         return (Ether(dst=in6_getnsmac(nsma)) /
 341                 IPv6(dst=d, src=self.remote_ip6) /
 342                 ICMPv6ND_NS(tgt=self.local_ip6) /
 343                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 344
 345     def resolve_arp(self, pg_interface=None):
 346         """Resolve ARP using provided packet-generator interface
 347
 348         :param pg_interface: interface used to resolve, if None then this
 349             interface is used
 350
 351         """
 352         if pg_interface is None:
 353             pg_interface = self
 354         self.test.logger.info("Sending ARP request for %s on port %s" %
 355                               (self.local_ip4, pg_interface.name))
 356         arp_req = self.create_arp_req()
 357         pg_interface.add_stream(arp_req)
 358         pg_interface.enable_capture()
 359         self.test.pg_start()
 360         self.test.logger.info(self.test.vapi.cli("show trace"))
 361         try:
 362             captured_packet = pg_interface.wait_for_packet(1)
 363         except:
 364             self.test.logger.info("No ARP received on port %s" %
 365                                   pg_interface.name)
 366             return
 367         arp_reply = captured_packet.copy()  # keep original for exception
 368         # Make Dot1AD packet content recognizable to scapy
 369         if arp_reply.type == 0x88a8:
 370             arp_reply.type = 0x8100
 371             arp_reply = Ether(str(arp_reply))
 372         try:
 373             if arp_reply[ARP].op == ARP.is_at:
 374                 self.test.logger.info("VPP %s MAC address is %s " %
 375                                       (self.name, arp_reply[ARP].hwsrc))
 376                 self._local_mac = arp_reply[ARP].hwsrc
 377             else:
 378                 self.test.logger.info("No ARP received on port %s" %
 379                                       pg_interface.name)
 380         except:
 381             self.test.logger.error(
 382                 ppp("Unexpected response to ARP request:", captured_packet))
 383             raise
 384
 385     def resolve_ndp(self, pg_interface=None, timeout=1):
 386         """Resolve NDP using provided packet-generator interface
 387
 388         :param pg_interface: interface used to resolve, if None then this
 389             interface is used
 390         :param timeout: how long to wait for response before giving up
 391
 392         """
 393         if pg_interface is None:
 394             pg_interface = self
 395         self.test.logger.info("Sending NDP request for %s on port %s" %
 396                               (self.local_ip6, pg_interface.name))
 397         ndp_req = self.create_ndp_req()
 398         pg_interface.add_stream(ndp_req)
 399         pg_interface.enable_capture()
 400         self.test.pg_start()
 401         now = time.time()
 402         deadline = now + timeout
 403         # Enabling IPv6 on an interface can generate more than the
 404         # ND reply we are looking for (namely MLD). So loop through
 405         # the replies to look for want we want.
 406         while now < deadline:
 407             try:
 408                 captured_packet = pg_interface.wait_for_packet(
 409                     deadline - now, filter_out_fn=None)
 410             except:
 411                 self.test.logger.error(
 412                     "Timeout while waiting for NDP response")
 413                 raise
 414             ndp_reply = captured_packet.copy()  # keep original for exception
 415             # Make Dot1AD packet content recognizable to scapy
 416             if ndp_reply.type == 0x88a8:
 417                 ndp_reply.type = 0x8100
 418                 ndp_reply = Ether(str(ndp_reply))
 419             try:
 420                 ndp_na = ndp_reply[ICMPv6ND_NA]
 421                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 422                 self.test.logger.info("VPP %s MAC address is %s " %
 423                                       (self.name, opt.lladdr))
 424                 self._local_mac = opt.lladdr
 425                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 426                 # we now have the MAC we've been after
 427                 return
 428             except:
 429                 self.test.logger.info(
 430                     ppp("Unexpected response to NDP request:",
 431                         captured_packet))
 432             now = time.time()
 433
 434         self.test.logger.debug(self.test.vapi.cli("show trace"))
 435         raise Exception("Timeout while waiting for NDP response")