test/vpp_pg_interface.py

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