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 from scapy.utils import wrpcap, rdpcap, PcapReader
   7 from scapy.plist import PacketList
   8 from vpp_interface import VppInterface
   9
  10 from scapy.layers.l2 import Ether, ARP
  11 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
  12     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
  13     IPv6ExtHdrHopByHop
  14 from util import ppp, ppc
  15 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  16 from scapy.utils import inet_pton, inet_ntop
  17
  18
  19 class CaptureTimeoutError(Exception):
  20     """ Exception raised if capture or packet doesn't appear within timeout """
  21     pass
  22
  23
  24 def is_ipv6_misc(p):
  25     """ Is packet one of uninteresting IPv6 broadcasts? """
  26     if p.haslayer(ICMPv6ND_RA):
  27         if in6_ismaddr(p[IPv6].dst):
  28             return True
  29     if p.haslayer(IPv6ExtHdrHopByHop):
  30         for o in p[IPv6ExtHdrHopByHop].options:
  31             if isinstance(o, RouterAlert):
  32                 return True
  33     return False
  34
  35
  36 class VppPGInterface(VppInterface):
  37     """
  38     VPP packet-generator interface
  39     """
  40
  41     @property
  42     def pg_index(self):
  43         """packet-generator interface index assigned by VPP"""
  44         return self._pg_index
  45
  46     @property
  47     def out_path(self):
  48         """pcap file path - captured packets"""
  49         return self._out_path
  50
  51     @property
  52     def in_path(self):
  53         """ pcap file path - injected packets"""
  54         return self._in_path
  55
  56     @property
  57     def capture_cli(self):
  58         """CLI string to start capture on this interface"""
  59         return self._capture_cli
  60
  61     @property
  62     def cap_name(self):
  63         """capture name for this interface"""
  64         return self._cap_name
  65
  66     @property
  67     def input_cli(self):
  68         """CLI string to load the injected packets"""
  69         return self._input_cli
  70
  71     @property
  72     def in_history_counter(self):
  73         """Self-incrementing counter used when renaming old pcap files"""
  74         v = self._in_history_counter
  75         self._in_history_counter += 1
  76         return v
  77
  78     @property
  79     def out_history_counter(self):
  80         """Self-incrementing counter used when renaming old pcap files"""
  81         v = self._out_history_counter
  82         self._out_history_counter += 1
  83         return v
  84
  85     def __init__(self, test, pg_index):
  86         """ Create VPP packet-generator interface """
  87         r = test.vapi.pg_create_interface(pg_index)
  88         self._sw_if_index = r.sw_if_index
  89
  90         super(VppPGInterface, self).__init__(test)
  91
  92         self._in_history_counter = 0
  93         self._out_history_counter = 0
  94         self._out_assert_counter = 0
  95         self._pg_index = pg_index
  96         self._out_file = "pg%u_out.pcap" % self.pg_index
  97         self._out_path = self.test.tempdir + "/" + self._out_file
  98         self._in_file = "pg%u_in.pcap" % self.pg_index
  99         self._in_path = self.test.tempdir + "/" + self._in_file
 100         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
 101             self.pg_index, self.out_path)
 102         self._cap_name = "pcap%u" % self.sw_if_index
 103         self._input_cli = \
 104             "packet-generator new pcap %s source pg%u name %s" % (
 105                 self.in_path, self.pg_index, self.cap_name)
 106
 107     def enable_capture(self):
 108         """ Enable capture on this packet-generator interface"""
 109         try:
 110             if os.path.isfile(self.out_path):
 111                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \
 112                     (self.test.tempdir,
 113                      time.time(),
 114                      self.name,
 115                      self.out_history_counter,
 116                      self._out_file)
 117                 self.test.logger.debug("Renaming %s->%s" %
 118                                        (self.out_path, name))
 119                 os.rename(self.out_path, name)
 120         except:
 121             pass
 122         # FIXME this should be an API, but no such exists atm
 123         self.test.vapi.cli(self.capture_cli)
 124         self._pcap_reader = None
 125
 126     def add_stream(self, pkts):
 127         """
 128         Add a stream of packets to this packet-generator
 129
 130         :param pkts: iterable packets
 131
 132         """
 133         try:
 134             if os.path.isfile(self.in_path):
 135                 name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %\
 136                     (self.test.tempdir,
 137                      time.time(),
 138                      self.name,
 139                      self.in_history_counter,
 140                      self._in_file)
 141                 self.test.logger.debug("Renaming %s->%s" %
 142                                        (self.in_path, name))
 143                 os.rename(self.in_path, name)
 144         except:
 145             pass
 146         wrpcap(self.in_path, pkts)
 147         self.test.register_capture(self.cap_name)
 148         # FIXME this should be an API, but no such exists atm
 149         self.test.vapi.cli(self.input_cli)
 150
 151     def generate_debug_aid(self, kind):
 152         """ Create a hardlink to the out file with a counter and a file
 153         containing stack trace to ease debugging in case of multiple capture
 154         files present. """
 155         self.test.logger.debug("Generating debug aid for %s on %s" %
 156                                (kind, self._name))
 157         link_path, stack_path = ["%s/debug_%s_%s_%s.%s" %
 158                                  (self.test.tempdir, self._name,
 159                                   self._out_assert_counter, kind, suffix)
 160                                  for suffix in ["pcap", "stack"]
 161                                  ]
 162         os.link(self.out_path, link_path)
 163         with open(stack_path, "w") as f:
 164             f.writelines(format_stack())
 165         self._out_assert_counter += 1
 166
 167     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 168         """ Helper method to get capture and filter it """
 169         try:
 170             if not self.wait_for_capture_file(timeout):
 171                 return None
 172             output = rdpcap(self.out_path)
 173             self.test.logger.debug("Capture has %s packets" % len(output.res))
 174         except:
 175             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 176                                    (self.out_path, format_exc()))
 177             return None
 178         before = len(output.res)
 179         if filter_out_fn:
 180             output.res = [p for p in output.res if not filter_out_fn(p)]
 181         removed = before - len(output.res)
 182         if removed:
 183             self.test.logger.debug(
 184                 "Filtered out %s packets from capture (returning %s)" %
 185                 (removed, len(output.res)))
 186         return output
 187
 188     def get_capture(self, expected_count=None, remark=None, timeout=1,
 189                     filter_out_fn=is_ipv6_misc):
 190         """ Get captured packets
 191
 192         :param expected_count: expected number of packets to capture, if None,
 193                                then self.test.packet_count_for_dst_pg_idx is
 194                                used to lookup the expected count
 195         :param remark: remark printed into debug logs
 196         :param timeout: how long to wait for packets
 197         :param filter_out_fn: filter applied to each packet, packets for which
 198                               the filter returns True are removed from capture
 199         :returns: iterable packets
 200         """
 201         remaining_time = timeout
 202         capture = None
 203         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 204         based_on = "based on provided argument"
 205         if expected_count is None:
 206             expected_count = \
 207                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 208             based_on = "based on stored packet_infos"
 209             if expected_count == 0:
 210                 raise Exception(
 211                     "Internal error, expected packet count for %s is 0!" %
 212                     name)
 213         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 214             expected_count, based_on, name))
 215         while remaining_time > 0:
 216             before = time.time()
 217             capture = self._get_capture(remaining_time, filter_out_fn)
 218             elapsed_time = time.time() - before
 219             if capture:
 220                 if len(capture.res) == expected_count:
 221                     # bingo, got the packets we expected
 222                     return capture
 223                 elif len(capture.res) > expected_count:
 224                     self.test.logger.error(
 225                         ppc("Unexpected packets captured:", capture))
 226                     break
 227                 else:
 228                     self.test.logger.debug("Partial capture containing %s "
 229                                            "packets doesn't match expected "
 230                                            "count %s (yet?)" %
 231                                            (len(capture.res), expected_count))
 232             elif expected_count == 0:
 233                 # bingo, got None as we expected - return empty capture
 234                 return PacketList()
 235             remaining_time -= elapsed_time
 236         if capture:
 237             self.generate_debug_aid("count-mismatch")
 238             raise Exception("Captured packets mismatch, captured %s packets, "
 239                             "expected %s packets on %s" %
 240                             (len(capture.res), expected_count, name))
 241         else:
 242             raise Exception("No packets captured on %s" % name)
 243
 244     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 245         """ Assert that nothing unfiltered was captured on interface
 246
 247         :param remark: remark printed into debug logs
 248         :param filter_out_fn: filter applied to each packet, packets for which
 249                               the filter returns True are removed from capture
 250         """
 251         if os.path.isfile(self.out_path):
 252             try:
 253                 capture = self.get_capture(
 254                     0, remark=remark, filter_out_fn=filter_out_fn)
 255                 if not capture or len(capture.res) == 0:
 256                     # junk filtered out, we're good
 257                     return
 258             except:
 259                 pass
 260             self.generate_debug_aid("empty-assert")
 261             if remark:
 262                 raise AssertionError(
 263                     "Non-empty capture file present for interface %s (%s)" %
 264                     (self.name, remark))
 265             else:
 266                 raise AssertionError("Capture file present for interface %s" %
 267                                      self.name)
 268
 269     def wait_for_capture_file(self, timeout=1):
 270         """
 271         Wait until pcap capture file appears
 272
 273         :param timeout: How long to wait for the packet (default 1s)
 274
 275         :returns: True/False if the file is present or appears within timeout
 276         """
 277         deadline = time.time() + timeout
 278         if not os.path.isfile(self.out_path):
 279             self.test.logger.debug("Waiting for capture file %s to appear, "
 280                                    "timeout is %ss" % (self.out_path, timeout))
 281         else:
 282             self.test.logger.debug("Capture file %s already exists" %
 283                                    self.out_path)
 284             return True
 285         while time.time() < deadline:
 286             if os.path.isfile(self.out_path):
 287                 break
 288             time.sleep(0)  # yield
 289         if os.path.isfile(self.out_path):
 290             self.test.logger.debug("Capture file appeared after %fs" %
 291                                    (time.time() - (deadline - timeout)))
 292         else:
 293             self.test.logger.debug("Timeout - capture file still nowhere")
 294             return False
 295         return True
 296
 297     def verify_enough_packet_data_in_pcap(self):
 298         """
 299         Check if enough data is available in file handled by internal pcap
 300         reader so that a whole packet can be read.
 301
 302         :returns: True if enough data present, else False
 303         """
 304         orig_pos = self._pcap_reader.f.tell()  # save file position
 305         enough_data = False
 306         # read packet header from pcap
 307         packet_header_size = 16
 308         caplen = None
 309         end_pos = None
 310         hdr = self._pcap_reader.f.read(packet_header_size)
 311         if len(hdr) == packet_header_size:
 312             # parse the capture length - caplen
 313             sec, usec, caplen, wirelen = struct.unpack(
 314                 self._pcap_reader.endian + "IIII", hdr)
 315             self._pcap_reader.f.seek(0, 2)  # seek to end of file
 316             end_pos = self._pcap_reader.f.tell()  # get position at end
 317             if end_pos >= orig_pos + len(hdr) + caplen:
 318                 enough_data = True  # yay, we have enough data
 319         self._pcap_reader.f.seek(orig_pos, 0)  # restore original position
 320         return enough_data
 321
 322     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 323         """
 324         Wait for next packet captured with a timeout
 325
 326         :param timeout: How long to wait for the packet
 327
 328         :returns: Captured packet if no packet arrived within timeout
 329         :raises Exception: if no packet arrives within timeout
 330         """
 331         deadline = time.time() + timeout
 332         if self._pcap_reader is None:
 333             if not self.wait_for_capture_file(timeout):
 334                 raise CaptureTimeoutError("Capture file %s did not appear "
 335                                           "within timeout" % self.out_path)
 336             while time.time() < deadline:
 337                 try:
 338                     self._pcap_reader = PcapReader(self.out_path)
 339                     break
 340                 except:
 341                     self.test.logger.debug(
 342                         "Exception in scapy.PcapReader(%s): %s" %
 343                         (self.out_path, format_exc()))
 344         if not self._pcap_reader:
 345             raise CaptureTimeoutError("Capture file %s did not appear within "
 346                                       "timeout" % self.out_path)
 347
 348         poll = False
 349         if timeout > 0:
 350             self.test.logger.debug("Waiting for packet")
 351         else:
 352             poll = True
 353             self.test.logger.debug("Polling for packet")
 354         while time.time() < deadline or poll:
 355             if not self.verify_enough_packet_data_in_pcap():
 356                 time.sleep(0)  # yield
 357                 poll = False
 358                 continue
 359             p = self._pcap_reader.recv()
 360             if p is not None:
 361                 if filter_out_fn is not None and filter_out_fn(p):
 362                     self.test.logger.debug(
 363                         "Packet received after %ss was filtered out" %
 364                         (time.time() - (deadline - timeout)))
 365                 else:
 366                     self.test.logger.debug(
 367                         "Packet received after %fs" %
 368                         (time.time() - (deadline - timeout)))
 369                     return p
 370             time.sleep(0)  # yield
 371             poll = False
 372         self.test.logger.debug("Timeout - no packets received")
 373         raise CaptureTimeoutError("Packet didn't arrive within timeout")
 374
 375     def create_arp_req(self):
 376         """Create ARP request applicable for this interface"""
 377         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 378                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 379                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 380
 381     def create_ndp_req(self):
 382         """Create NDP - NS applicable for this interface"""
 383         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 384         d = inet_ntop(socket.AF_INET6, nsma)
 385
 386         return (Ether(dst=in6_getnsmac(nsma)) /
 387                 IPv6(dst=d, src=self.remote_ip6) /
 388                 ICMPv6ND_NS(tgt=self.local_ip6) /
 389                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 390
 391     def resolve_arp(self, pg_interface=None):
 392         """Resolve ARP using provided packet-generator interface
 393
 394         :param pg_interface: interface used to resolve, if None then this
 395             interface is used
 396
 397         """
 398         if pg_interface is None:
 399             pg_interface = self
 400         self.test.logger.info("Sending ARP request for %s on port %s" %
 401                               (self.local_ip4, pg_interface.name))
 402         arp_req = self.create_arp_req()
 403         pg_interface.add_stream(arp_req)
 404         pg_interface.enable_capture()
 405         self.test.pg_start()
 406         self.test.logger.info(self.test.vapi.cli("show trace"))
 407         try:
 408             captured_packet = pg_interface.wait_for_packet(1)
 409         except:
 410             self.test.logger.info("No ARP received on port %s" %
 411                                   pg_interface.name)
 412             return
 413         arp_reply = captured_packet.copy()  # keep original for exception
 414         # Make Dot1AD packet content recognizable to scapy
 415         if arp_reply.type == 0x88a8:
 416             arp_reply.type = 0x8100
 417             arp_reply = Ether(str(arp_reply))
 418         try:
 419             if arp_reply[ARP].op == ARP.is_at:
 420                 self.test.logger.info("VPP %s MAC address is %s " %
 421                                       (self.name, arp_reply[ARP].hwsrc))
 422                 self._local_mac = arp_reply[ARP].hwsrc
 423             else:
 424                 self.test.logger.info("No ARP received on port %s" %
 425                                       pg_interface.name)
 426         except:
 427             self.test.logger.error(
 428                 ppp("Unexpected response to ARP request:", captured_packet))
 429             raise
 430
 431     def resolve_ndp(self, pg_interface=None, timeout=1):
 432         """Resolve NDP using provided packet-generator interface
 433
 434         :param pg_interface: interface used to resolve, if None then this
 435             interface is used
 436         :param timeout: how long to wait for response before giving up
 437
 438         """
 439         if pg_interface is None:
 440             pg_interface = self
 441         self.test.logger.info("Sending NDP request for %s on port %s" %
 442                               (self.local_ip6, pg_interface.name))
 443         ndp_req = self.create_ndp_req()
 444         pg_interface.add_stream(ndp_req)
 445         pg_interface.enable_capture()
 446         self.test.pg_start()
 447         now = time.time()
 448         deadline = now + timeout
 449         # Enabling IPv6 on an interface can generate more than the
 450         # ND reply we are looking for (namely MLD). So loop through
 451         # the replies to look for want we want.
 452         while now < deadline:
 453             try:
 454                 captured_packet = pg_interface.wait_for_packet(
 455                     deadline - now, filter_out_fn=None)
 456             except:
 457                 self.test.logger.error(
 458                     "Timeout while waiting for NDP response")
 459                 raise
 460             ndp_reply = captured_packet.copy()  # keep original for exception
 461             # Make Dot1AD packet content recognizable to scapy
 462             if ndp_reply.type == 0x88a8:
 463                 ndp_reply.type = 0x8100
 464                 ndp_reply = Ether(str(ndp_reply))
 465             try:
 466                 ndp_na = ndp_reply[ICMPv6ND_NA]
 467                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 468                 self.test.logger.info("VPP %s MAC address is %s " %
 469                                       (self.name, opt.lladdr))
 470                 self._local_mac = opt.lladdr
 471                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 472                 # we now have the MAC we've been after
 473                 return
 474             except:
 475                 self.test.logger.info(
 476                     ppp("Unexpected response to NDP request:",
 477                         captured_packet))
 478             now = time.time()
 479
 480         self.test.logger.debug(self.test.vapi.cli("show trace"))
 481         raise Exception("Timeout while waiting for NDP response")