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 enable_capture(self):
  95         """ Enable capture on this packet-generator interface"""
  96         try:
  97             if os.path.isfile(self.out_path):
  98                 os.rename(self.out_path,
  99                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 100                           (self.test.tempdir,
 101                            time.time(),
 102                            self.name,
 103                            self.out_history_counter,
 104                            self._out_file))
 105         except:
 106             pass
 107         # FIXME this should be an API, but no such exists atm
 108         self.test.vapi.cli(self.capture_cli)
 109         self._pcap_reader = None
 110
 111     def add_stream(self, pkts):
 112         """
 113         Add a stream of packets to this packet-generator
 114
 115         :param pkts: iterable packets
 116
 117         """
 118         try:
 119             if os.path.isfile(self.in_path):
 120                 os.rename(self.in_path,
 121                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 122                           (self.test.tempdir,
 123                            time.time(),
 124                            self.name,
 125                            self.in_history_counter,
 126                            self._in_file))
 127         except:
 128             pass
 129         wrpcap(self.in_path, pkts)
 130         self.test.register_capture(self.cap_name)
 131         # FIXME this should be an API, but no such exists atm
 132         self.test.vapi.cli(self.input_cli)
 133
 134     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 135         """ Helper method to get capture and filter it """
 136         try:
 137             if not self.wait_for_capture_file(timeout):
 138                 return None
 139             output = rdpcap(self.out_path)
 140             self.test.logger.debug("Capture has %s packets" % len(output.res))
 141         except:
 142             self.test.logger.debug("Exception in scapy.rdpcap(%s): %s" %
 143                                    (self.out_path, format_exc()))
 144             return None
 145         before = len(output.res)
 146         if filter_out_fn:
 147             output.res = [p for p in output.res if not filter_out_fn(p)]
 148         removed = len(output.res) - before
 149         if removed:
 150             self.test.logger.debug(
 151                 "Filtered out %s packets from capture (returning %s)" %
 152                 (removed, len(output.res)))
 153         return output
 154
 155     def get_capture(self, expected_count=None, remark=None, timeout=1,
 156                     filter_out_fn=is_ipv6_misc):
 157         """ Get captured packets
 158
 159         :param expected_count: expected number of packets to capture, if None,
 160                                then self.test.packet_count_for_dst_pg_idx is
 161                                used to lookup the expected count
 162         :param remark: remark printed into debug logs
 163         :param timeout: how long to wait for packets
 164         :param filter_out_fn: filter applied to each packet, packets for which
 165                               the filter returns True are removed from capture
 166         :returns: iterable packets
 167         """
 168         remaining_time = timeout
 169         capture = None
 170         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 171         based_on = "based on provided argument"
 172         if expected_count is None:
 173             expected_count = \
 174                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 175             based_on = "based on stored packet_infos"
 176             if expected_count == 0:
 177                 raise Exception(
 178                     "Internal error, expected packet count for %s is 0!" % name)
 179         self.test.logger.debug("Expecting to capture %s(%s) packets on %s" % (
 180             expected_count, based_on, name))
 181         while remaining_time > 0:
 182             before = time.time()
 183             capture = self._get_capture(remaining_time, filter_out_fn)
 184             elapsed_time = time.time() - before
 185             if capture:
 186                 if len(capture.res) == expected_count:
 187                     # bingo, got the packets we expected
 188                     return capture
 189             elif expected_count == 0:
 190                 return None
 191             remaining_time -= elapsed_time
 192         if capture:
 193             raise Exception("Captured packets mismatch, captured %s packets, "
 194                             "expected %s packets on %s" %
 195                             (len(capture.res), expected_count, name))
 196         else:
 197             raise Exception("No packets captured on %s" % name)
 198
 199     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 200         """ Assert that nothing unfiltered was captured on interface
 201
 202         :param remark: remark printed into debug logs
 203         :param filter_out_fn: filter applied to each packet, packets for which
 204                               the filter returns True are removed from capture
 205         """
 206         if os.path.isfile(self.out_path):
 207             try:
 208                 capture = self.get_capture(
 209                     0, remark=remark, filter_out_fn=filter_out_fn)
 210                 if capture:
 211                     if len(capture.res) == 0:
 212                         # junk filtered out, we're good
 213                         return
 214                     self.test.logger.error(
 215                         ppc("Unexpected packets captured:", capture))
 216             except:
 217                 pass
 218             if remark:
 219                 raise AssertionError(
 220                     "Non-empty capture file present for interface %s(%s)" %
 221                     (self.name, remark))
 222             else:
 223                 raise AssertionError(
 224                     "Non-empty capture file present for interface %s" %
 225                     self.name)
 226
 227     def wait_for_capture_file(self, timeout=1):
 228         """
 229         Wait until pcap capture file appears
 230
 231         :param timeout: How long to wait for the packet (default 1s)
 232
 233         :returns: True/False if the file is present or appears within timeout
 234         """
 235         limit = time.time() + timeout
 236         if not os.path.isfile(self.out_path):
 237             self.test.logger.debug("Waiting for capture file %s to appear, "
 238                                    "timeout is %ss" % (self.out_path, timeout))
 239         else:
 240             self.test.logger.debug("Capture file %s already exists" %
 241                                    self.out_path)
 242             return True
 243         while time.time() < limit:
 244             if os.path.isfile(self.out_path):
 245                 break
 246             time.sleep(0)  # yield
 247         if os.path.isfile(self.out_path):
 248             self.test.logger.debug("Capture file appeared after %fs" %
 249                                    (time.time() - (limit - timeout)))
 250         else:
 251             self.test.logger.debug("Timeout - capture file still nowhere")
 252             return False
 253         return True
 254
 255     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 256         """
 257         Wait for next packet captured with a timeout
 258
 259         :param timeout: How long to wait for the packet
 260
 261         :returns: Captured packet if no packet arrived within timeout
 262         :raises Exception: if no packet arrives within timeout
 263         """
 264         deadline = time.time() + timeout
 265         if self._pcap_reader is None:
 266             if not self.wait_for_capture_file(timeout):
 267                 raise Exception("Capture file %s did not appear within "
 268                                 "timeout" % self.out_path)
 269             while time.time() < deadline:
 270                 try:
 271                     self._pcap_reader = PcapReader(self.out_path)
 272                     break
 273                 except:
 274                     self.test.logger.debug("Exception in scapy.PcapReader(%s): "
 275                                            "%s" % (self.out_path, format_exc()))
 276         if not self._pcap_reader:
 277             raise Exception("Capture file %s did not appear within "
 278                             "timeout" % self.out_path)
 279
 280         self.test.logger.debug("Waiting for packet")
 281         while time.time() < deadline:
 282             p = self._pcap_reader.recv()
 283             if p is not None:
 284                 if filter_out_fn is not None and filter_out_fn(p):
 285                     self.test.logger.debug(
 286                         "Packet received after %ss was filtered out" %
 287                         (time.time() - (deadline - timeout)))
 288                 else:
 289                     self.test.logger.debug("Packet received after %fs" %
 290                                            (time.time() - (deadline - timeout)))
 291                     return p
 292             time.sleep(0)  # yield
 293         self.test.logger.debug("Timeout - no packets received")
 294         raise Exception("Packet didn't arrive within timeout")
 295
 296     def create_arp_req(self):
 297         """Create ARP request applicable for this interface"""
 298         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 299                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 300                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 301
 302     def create_ndp_req(self):
 303         """Create NDP - NS applicable for this interface"""
 304         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 305                 IPv6(src=self.remote_ip6, dst=self.local_ip6) /
 306                 ICMPv6ND_NS(tgt=self.local_ip6) /
 307                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 308
 309     def resolve_arp(self, pg_interface=None):
 310         """Resolve ARP using provided packet-generator interface
 311
 312         :param pg_interface: interface used to resolve, if None then this
 313             interface is used
 314
 315         """
 316         if pg_interface is None:
 317             pg_interface = self
 318         self.test.logger.info("Sending ARP request for %s on port %s" %
 319                               (self.local_ip4, pg_interface.name))
 320         arp_req = self.create_arp_req()
 321         pg_interface.add_stream(arp_req)
 322         pg_interface.enable_capture()
 323         self.test.pg_start()
 324         self.test.logger.info(self.test.vapi.cli("show trace"))
 325         try:
 326             captured_packet = pg_interface.wait_for_packet(1)
 327         except:
 328             self.test.logger.info("No ARP received on port %s" %
 329                                   pg_interface.name)
 330             return
 331         arp_reply = captured_packet.copy()  # keep original for exception
 332         # Make Dot1AD packet content recognizable to scapy
 333         if arp_reply.type == 0x88a8:
 334             arp_reply.type = 0x8100
 335             arp_reply = Ether(str(arp_reply))
 336         try:
 337             if arp_reply[ARP].op == ARP.is_at:
 338                 self.test.logger.info("VPP %s MAC address is %s " %
 339                                       (self.name, arp_reply[ARP].hwsrc))
 340                 self._local_mac = arp_reply[ARP].hwsrc
 341             else:
 342                 self.test.logger.info("No ARP received on port %s" %
 343                                       pg_interface.name)
 344         except:
 345             self.test.logger.error(
 346                 ppp("Unexpected response to ARP request:", captured_packet))
 347             raise
 348
 349     def resolve_ndp(self, pg_interface=None, timeout=1):
 350         """Resolve NDP using provided packet-generator interface
 351
 352         :param pg_interface: interface used to resolve, if None then this
 353             interface is used
 354         :param timeout: how long to wait for response before giving up
 355
 356         """
 357         if pg_interface is None:
 358             pg_interface = self
 359         self.test.logger.info("Sending NDP request for %s on port %s" %
 360                               (self.local_ip6, pg_interface.name))
 361         ndp_req = self.create_ndp_req()
 362         pg_interface.add_stream(ndp_req)
 363         pg_interface.enable_capture()
 364         self.test.pg_start()
 365         now = time.time()
 366         deadline = now + timeout
 367         # Enabling IPv6 on an interface can generate more than the
 368         # ND reply we are looking for (namely MLD). So loop through
 369         # the replies to look for want we want.
 370         while now < deadline:
 371             try:
 372                 captured_packet = pg_interface.wait_for_packet(
 373                     deadline - now, filter_out_fn=None)
 374             except:
 375                 self.test.logger.error("Timeout while waiting for NDP response")
 376                 raise
 377             ndp_reply = captured_packet.copy()  # keep original for exception
 378             # Make Dot1AD packet content recognizable to scapy
 379             if ndp_reply.type == 0x88a8:
 380                 ndp_reply.type = 0x8100
 381                 ndp_reply = Ether(str(ndp_reply))
 382             try:
 383                 ndp_na = ndp_reply[ICMPv6ND_NA]
 384                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 385                 self.test.logger.info("VPP %s MAC address is %s " %
 386                                       (self.name, opt.lladdr))
 387                 self._local_mac = opt.lladdr
 388                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 389                 # we now have the MAC we've been after
 390                 return
 391             except:
 392                 self.test.logger.info(
 393                     ppp("Unexpected response to NDP request:", captured_packet))
 394             now = time.time()
 395
 396         self.test.logger.debug(self.test.vapi.cli("show trace"))
 397         raise Exception("Timeout while waiting for NDP response")