test/vpp_pg_interface.py

   1 import os
   2 import time
   3 import socket
   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 from scapy.utils import inet_pton, inet_ntop
  19
  20
  21 class CaptureTimeoutError(Exception):
  22     """ Exception raised if capture or packet doesn't appear within timeout """
  23     pass
  24
  25
  26 def is_ipv6_misc(p):
  27     """ Is packet one of uninteresting IPv6 broadcasts? """
  28     if p.haslayer(ICMPv6ND_RA):
  29         if in6_ismaddr(p[IPv6].dst):
  30             return True
  31     if p.haslayer(IPv6ExtHdrHopByHop):
  32         for o in p[IPv6ExtHdrHopByHop].options:
  33             if isinstance(o, RouterAlert):
  34                 return True
  35     return False
  36
  37
  38 class VppPGInterface(VppInterface):
  39     """
  40     VPP packet-generator interface
  41     """
  42
  43     @property
  44     def pg_index(self):
  45         """packet-generator interface index assigned by VPP"""
  46         return self._pg_index
  47
  48     @property
  49     def out_path(self):
  50         """pcap file path - captured packets"""
  51         return self._out_path
  52
  53     @property
  54     def in_path(self):
  55         """ pcap file path - injected packets"""
  56         return self._in_path
  57
  58     @property
  59     def capture_cli(self):
  60         """CLI string to start capture on this interface"""
  61         return self._capture_cli
  62
  63     @property
  64     def cap_name(self):
  65         """capture name for this interface"""
  66         return self._cap_name
  67
  68     @property
  69     def input_cli(self):
  70         """CLI string to load the injected packets"""
  71         return self._input_cli
  72
  73     @property
  74     def in_history_counter(self):
  75         """Self-incrementing counter used when renaming old pcap files"""
  76         v = self._in_history_counter
  77         self._in_history_counter += 1
  78         return v
  79
  80     @property
  81     def out_history_counter(self):
  82         """Self-incrementing counter used when renaming old pcap files"""
  83         v = self._out_history_counter
  84         self._out_history_counter += 1
  85         return v
  86
  87     def __init__(self, test, pg_index):
  88         """ Create VPP packet-generator interface """
  89         super(VppPGInterface, self).__init__(test)
  90
  91         r = test.vapi.pg_create_interface(pg_index)
  92         self.set_sw_if_index(r.sw_if_index)
  93
  94         self._in_history_counter = 0
  95         self._out_history_counter = 0
  96         self._out_assert_counter = 0
  97         self._pg_index = pg_index
  98         self._out_file = "pg%u_out.pcap" % self.pg_index
  99         self._out_path = self.test.tempdir + "/" + self._out_file
 100         self._in_file = "pg%u_in.pcap" % self.pg_index
 101         self._in_path = self.test.tempdir + "/" + self._in_file
 102         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 103             self.pg_index, self.out_path)
 104         self._cap_name = "pcap%u" % self.sw_if_index
 105         self._input_cli = \
 106             "packet-generator new pcap %s source pg%u name %s" % (
 107                 self.in_path, self.pg_index, self.cap_name)
 108
 109     def enable_capture(self):
 110         """ Enable capture on this packet-generator interface"""
 111         try:
 112             if os.path.isfile(self.out_path):
 113                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 114                     (self.test.tempdir,
 115                      time.time(),
 116                      self.name,
 117                      self.out_history_counter,
 118                      self._out_file)
 119                 self.test.logger.debug("Renaming %s->%s" %
 120                                        (self.out_path, name))
 121                 os.rename(self.out_path, name)
 122         except:
 123             pass
 124         # FIXME this should be an API, but no such exists atm
 125         self.test.vapi.cli(self.capture_cli)
 126         self._pcap_reader = None
 127
 128     def add_stream(self, pkts):
 129         """
 130         Add a stream of packets to this packet-generator
 131
 132         :param pkts: iterable packets
 133
 134         """
 135         try:
 136             if os.path.isfile(self.in_path):
 137                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %\
 138                     (self.test.tempdir,
 139                      time.time(),
 140                      self.name,
 141                      self.in_history_counter,
 142                      self._in_file)
 143                 self.test.logger.debug("Renaming %s->%s" %
 144                                        (self.in_path, name))
 145                 os.rename(self.in_path, name)
 146         except:
 147             pass
 148         wrpcap(self.in_path, pkts)
 149         self.test.register_capture(self.cap_name)
 150         # FIXME this should be an API, but no such exists atm
 151         self.test.vapi.cli(self.input_cli)
 152
 153     def generate_debug_aid(self, kind):
 154         """ Create a hardlink to the out file with a counter and a file
 155         containing stack trace to ease debugging in case of multiple capture
 156         files present. """
 157         self.test.logger.debug("Generating debug aid for %s on %s" %
 158                                (kind, self._name))
 159         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 160                                  (self.test.tempdir, self._name,
 161                                   self._out_assert_counter, kind, suffix)
 162                                  for suffix in ["pcap", "stack"]
 163                                  ]
 164         os.link(self.out_path, link_path)
 165         with open(stack_path, "w") as f:
 166             f.writelines(format_stack())
 167         self._out_assert_counter += 1
 168
 169     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 170         """ Helper method to get capture and filter it """
 171         try:
 172             if not self.wait_for_capture_file(timeout):
 173                 return None
 174             output = rdpcap(self.out_path)
 175             self.test.logger.debug("Capture has %s packets" % len(output.res))
 176         except:
 177             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 178                                    (self.out_path, format_exc()))
 179             return None
 180         before = len(output.res)
 181         if filter_out_fn:
 182             output.res = [p for p in output.res if not filter_out_fn(p)]
 183         removed = before - len(output.res)
 184         if removed:
 185             self.test.logger.debug(
 186                 "Filtered out %s packets from capture (returning %s)" %
 187                 (removed, len(output.res)))
 188         return output
 189
 190     def get_capture(self, expected_count=None, remark=None, timeout=1,
 191                     filter_out_fn=is_ipv6_misc):
 192         """ Get captured packets
 193
 194         :param expected_count: expected number of packets to capture, if None,
 195                                then self.test.packet_count_for_dst_pg_idx is
 196                                used to lookup the expected count
 197         :param remark: remark printed into debug logs
 198         :param timeout: how long to wait for packets
 199         :param filter_out_fn: filter applied to each packet, packets for which
 200                               the filter returns True are removed from capture
 201         :returns: iterable packets
 202         """
 203         remaining_time = timeout
 204         capture = None
 205         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 206         based_on = "based on provided argument"
 207         if expected_count is None:
 208             expected_count = \
 209                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 210             based_on = "based on stored packet_infos"
 211             if expected_count == 0:
 212                 raise Exception(
 213                     "Internal error, expected packet count for %s is 0!" %
 214                     name)
 215         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 216             expected_count, based_on, name))
 217         while remaining_time > 0:
 218             before = time.time()
 219             capture = self._get_capture(remaining_time, filter_out_fn)
 220             elapsed_time = time.time() - before
 221             if capture:
 222                 if len(capture.res) == expected_count:
 223                     # bingo, got the packets we expected
 224                     return capture
 225                 elif len(capture.res) > expected_count:
 226                     self.test.logger.error(
 227                         ppc("Unexpected packets captured:", capture))
 228                     break
 229                 else:
 230                     self.test.logger.debug("Partial capture containing %s "
 231                                            "packets doesn't match expected "
 232                                            "count %s (yet?)" %
 233                                            (len(capture.res), expected_count))
 234             elif expected_count == 0:
 235                 # bingo, got None as we expected - return empty capture
 236                 return PacketList()
 237             remaining_time -= elapsed_time
 238         if capture:
 239             self.generate_debug_aid("count-mismatch")
 240             raise Exception("Captured packets mismatch, captured %s packets, "
 241                             "expected %s packets on %s" %
 242                             (len(capture.res), expected_count, name))
 243         else:
 244             raise Exception("No packets captured on %s" % name)
 245
 246     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 247         """ Assert that nothing unfiltered was captured on interface
 248
 249         :param remark: remark printed into debug logs
 250         :param filter_out_fn: filter applied to each packet, packets for which
 251                               the filter returns True are removed from capture
 252         """
 253         if os.path.isfile(self.out_path):
 254             try:
 255                 capture = self.get_capture(
 256                     0, remark=remark, filter_out_fn=filter_out_fn)
 257                 if not capture or len(capture.res) == 0:
 258                     # junk filtered out, we're good
 259                     return
 260             except:
 261                 pass
 262             self.generate_debug_aid("empty-assert")
 263             if remark:
 264                 raise AssertionError(
 265                     "Non-empty capture file present for interface %s (%s)" %
 266                     (self.name, remark))
 267             else:
 268                 raise AssertionError("Capture file present for interface %s" %
 269                                      self.name)
 270
 271     def wait_for_capture_file(self, timeout=1):
 272         """
 273         Wait until pcap capture file appears
 274
 275         :param timeout: How long to wait for the packet (default 1s)
 276
 277         :returns: True/False if the file is present or appears within timeout
 278         """
 279         deadline = time.time() + timeout
 280         if not os.path.isfile(self.out_path):
 281             self.test.logger.debug("Waiting for capture file %s to appear, "
 282                                    "timeout is %ss" % (self.out_path, timeout))
 283         else:
 284             self.test.logger.debug("Capture file %s already exists" %
 285                                    self.out_path)
 286             return True
 287         while time.time() < deadline:
 288             if os.path.isfile(self.out_path):
 289                 break
 290             self._test.sleep(0)  # yield
 291         if os.path.isfile(self.out_path):
 292             self.test.logger.debug("Capture file appeared after %fs" %
 293                                    (time.time() - (deadline - timeout)))
 294         else:
 295             self.test.logger.debug("Timeout - capture file still nowhere")
 296             return False
 297         return True
 298
 299     def verify_enough_packet_data_in_pcap(self):
 300         """
 301         Check if enough data is available in file handled by internal pcap
 302         reader so that a whole packet can be read.
 303
 304         :returns: True if enough data present, else False
 305         """
 306         orig_pos = self._pcap_reader.f.tell()  # save file position
 307         enough_data = False
 308         # read packet header from pcap
 309         packet_header_size = 16
 310         caplen = None
 311         end_pos = None
 312         hdr = self._pcap_reader.f.read(packet_header_size)
 313         if len(hdr) == packet_header_size:
 314             # parse the capture length - caplen
 315             sec, usec, caplen, wirelen = struct.unpack(
 316                 self._pcap_reader.endian + "IIII", hdr)
 317             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 318             end_pos = self._pcap_reader.f.tell()  # get position at end
 319             if end_pos >= orig_pos + len(hdr) + caplen:
 320                 enough_data = True  # yay, we have enough data
 321         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 322         return enough_data
 323
 324     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 325         """
 326         Wait for next packet captured with a timeout
 327
 328         :param timeout: How long to wait for the packet
 329
 330         :returns: Captured packet if no packet arrived within timeout
 331         :raises Exception: if no packet arrives within timeout
 332         """
 333         deadline = time.time() + timeout
 334         if self._pcap_reader is None:
 335             if not self.wait_for_capture_file(timeout):
 336                 raise CaptureTimeoutError("Capture file %s did not appear "
 337                                           "within timeout" % self.out_path)
 338             while time.time() < deadline:
 339                 try:
 340                     self._pcap_reader = PcapReader(self.out_path)
 341                     break
 342                 except:
 343                     self.test.logger.debug(
 344                         "Exception in scapy.PcapReader(%s): %s" %
 345                         (self.out_path, format_exc()))
 346         if not self._pcap_reader:
 347             raise CaptureTimeoutError("Capture file %s did not appear within "
 348                                       "timeout" % self.out_path)
 349
 350         poll = False
 351         if timeout > 0:
 352             self.test.logger.debug("Waiting for packet")
 353         else:
 354             poll = True
 355             self.test.logger.debug("Polling for packet")
 356         while time.time() < deadline or poll:
 357             if not self.verify_enough_packet_data_in_pcap():
 358                 self._test.sleep(0)  # yield
 359                 poll = False
 360                 continue
 361             p = self._pcap_reader.recv()
 362             if p is not None:
 363                 if filter_out_fn is not None and filter_out_fn(p):
 364                     self.test.logger.debug(
 365                         "Packet received after %ss was filtered out" %
 366                         (time.time() - (deadline - timeout)))
 367                 else:
 368                     self.test.logger.debug(
 369                         "Packet received after %fs" %
 370                         (time.time() - (deadline - timeout)))
 371                     return p
 372             self._test.sleep(0)  # yield
 373             poll = False
 374         self.test.logger.debug("Timeout - no packets received")
 375         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 376
 377     def create_arp_req(self):
 378         """Create ARP request applicable for this interface"""
 379         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 380                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 381                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 382
 383     def create_ndp_req(self):
 384         """Create NDP - NS applicable for this interface"""
 385         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 386         d = inet_ntop(socket.AF_INET6, nsma)
 387
 388         return (Ether(dst=in6_getnsmac(nsma)) /
 389                 IPv6(dst=d, src=self.remote_ip6) /
 390                 ICMPv6ND_NS(tgt=self.local_ip6) /
 391                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 392
 393     def resolve_arp(self, pg_interface=None):
 394         """Resolve ARP using provided packet-generator interface
 395
 396         :param pg_interface: interface used to resolve, if None then this
 397             interface is used
 398
 399         """
 400         if pg_interface is None:
 401             pg_interface = self
 402         self.test.logger.info("Sending ARP request for %s on port %s" %
 403                               (self.local_ip4, pg_interface.name))
 404         arp_req = self.create_arp_req()
 405         pg_interface.add_stream(arp_req)
 406         pg_interface.enable_capture()
 407         self.test.pg_start()
 408         self.test.logger.info(self.test.vapi.cli("show trace"))
 409         try:
 410             captured_packet = pg_interface.wait_for_packet(1)
 411         except:
 412             self.test.logger.info("No ARP received on port %s" %
 413                                   pg_interface.name)
 414             return
 415         arp_reply = captured_packet.copy()  # keep original for exception
 416         # Make Dot1AD packet content recognizable to scapy
 417         if arp_reply.type == 0x88a8:
 418             arp_reply.type = 0x8100
 419             arp_reply = Ether(scapy.compat.raw(arp_reply))
 420         try:
 421             if arp_reply[ARP].op == ARP.is_at:
 422                 self.test.logger.info("VPP %s MAC address is %s " %
 423                                       (self.name, arp_reply[ARP].hwsrc))
 424                 self._local_mac = arp_reply[ARP].hwsrc
 425             else:
 426                 self.test.logger.info("No ARP received on port %s" %
 427                                       pg_interface.name)
 428         except:
 429             self.test.logger.error(
 430                 ppp("Unexpected response to ARP request:", captured_packet))
 431             raise
 432
 433     def resolve_ndp(self, pg_interface=None, timeout=1):
 434         """Resolve NDP using provided packet-generator interface
 435
 436         :param pg_interface: interface used to resolve, if None then this
 437             interface is used
 438         :param timeout: how long to wait for response before giving up
 439
 440         """
 441         if pg_interface is None:
 442             pg_interface = self
 443         self.test.logger.info("Sending NDP request for %s on port %s" %
 444                               (self.local_ip6, pg_interface.name))
 445         ndp_req = self.create_ndp_req()
 446         pg_interface.add_stream(ndp_req)
 447         pg_interface.enable_capture()
 448         self.test.pg_start()
 449         now = time.time()
 450         deadline = now + timeout
 451         # Enabling IPv6 on an interface can generate more than the
 452         # ND reply we are looking for (namely MLD). So loop through
 453         # the replies to look for want we want.
 454         while now < deadline:
 455             try:
 456                 captured_packet = pg_interface.wait_for_packet(
 457                     deadline - now, filter_out_fn=None)
 458             except:
 459                 self.test.logger.error(
 460                     "Timeout while waiting for NDP response")
 461                 raise
 462             ndp_reply = captured_packet.copy()  # keep original for exception
 463             # Make Dot1AD packet content recognizable to scapy
 464             if ndp_reply.type == 0x88a8:
 465                 self._test.logger.info(
 466                     "Replacing EtherType: 0x88a8 with "
 467                     "0x8100 and regenerating Ethernet header. ")
 468                 ndp_reply.type = 0x8100
 469                 ndp_reply = Ether(scapy.compat.raw(ndp_reply))
 470             try:
 471                 ndp_na = ndp_reply[ICMPv6ND_NA]
 472                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 473                 self.test.logger.info("VPP %s MAC address is %s " %
 474                                       (self.name, opt.lladdr))
 475                 self._local_mac = opt.lladdr
 476                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 477                 # we now have the MAC we've been after
 478                 return
 479             except:
 480                 self.test.logger.info(
 481                     ppp("Unexpected response to NDP request:",
 482                         captured_packet))
 483             now = time.time()
 484
 485         self.test.logger.debug(self.test.vapi.cli("show trace"))
 486         raise Exception("Timeout while waiting for NDP response")