test/vpp_pg_interface.py

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