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 capture:
 217                     if len(capture.res) == 0:
 218                         # junk filtered out, we're good
 219                         return
 220                     self.test.logger.error(
 221                         ppc("Unexpected packets captured:", capture))
 222             except:
 223                 pass
 224             if remark:
 225                 raise AssertionError(
 226                     "Non-empty capture file present for interface %s(%s)" %
 227                     (self.name, remark))
 228             else:
 229                 raise AssertionError(
 230                     "Non-empty capture file present for interface %s" %
 231                     self.name)
 232
 233     def wait_for_capture_file(self, timeout=1):
 234         """
 235         Wait until pcap capture file appears
 236
 237         :param timeout: How long to wait for the packet (default 1s)
 238
 239         :returns: True/False if the file is present or appears within timeout
 240         """
 241         limit = time.time() + timeout
 242         if not os.path.isfile(self.out_path):
 243             self.test.logger.debug("Waiting for capture file %s to appear, "
 244                                    "timeout is %ss" % (self.out_path, timeout))
 245         else:
 246             self.test.logger.debug("Capture file %s already exists" %
 247                                    self.out_path)
 248             return True
 249         while time.time() < limit:
 250             if os.path.isfile(self.out_path):
 251                 break
 252             time.sleep(0)  # yield
 253         if os.path.isfile(self.out_path):
 254             self.test.logger.debug("Capture file appeared after %fs" %
 255                                    (time.time() - (limit - timeout)))
 256         else:
 257             self.test.logger.debug("Timeout - capture file still nowhere")
 258             return False
 259         return True
 260
 261     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 262         """
 263         Wait for next packet captured with a timeout
 264
 265         :param timeout: How long to wait for the packet
 266
 267         :returns: Captured packet if no packet arrived within timeout
 268         :raises Exception: if no packet arrives within timeout
 269         """
 270         deadline = time.time() + timeout
 271         if self._pcap_reader is None:
 272             if not self.wait_for_capture_file(timeout):
 273                 raise Exception("Capture file %s did not appear within "
 274                                 "timeout" % self.out_path)
 275             while time.time() < deadline:
 276                 try:
 277                     self._pcap_reader = PcapReader(self.out_path)
 278                     break
 279                 except:
 280                     self.test.logger.debug("Exception in scapy.PcapReader(%s): "
 281                                            "%s" % (self.out_path, format_exc()))
 282         if not self._pcap_reader:
 283             raise Exception("Capture file %s did not appear within "
 284                             "timeout" % self.out_path)
 285
 286         self.test.logger.debug("Waiting for packet")
 287         while time.time() < deadline:
 288             p = self._pcap_reader.recv()
 289             if p is not None:
 290                 if filter_out_fn is not None and filter_out_fn(p):
 291                     self.test.logger.debug(
 292                         "Packet received after %ss was filtered out" %
 293                         (time.time() - (deadline - timeout)))
 294                 else:
 295                     self.test.logger.debug("Packet received after %fs" %
 296                                            (time.time() - (deadline - timeout)))
 297                     return p
 298             time.sleep(0)  # yield
 299         self.test.logger.debug("Timeout - no packets received")
 300         raise Exception("Packet didn't arrive within timeout")
 301
 302     def create_arp_req(self):
 303         """Create ARP request applicable for this interface"""
 304         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 305                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 306                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 307
 308     def create_ndp_req(self):
 309         """Create NDP - NS applicable for this interface"""
 310         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 311         d = inet_ntop(socket.AF_INET6, nsma)
 312
 313         return (Ether(dst=in6_getnsmac(nsma)) /
 314                 IPv6(dst=d, src=self.remote_ip6) /
 315                 ICMPv6ND_NS(tgt=self.local_ip6) /
 316                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 317
 318     def resolve_arp(self, pg_interface=None):
 319         """Resolve ARP using provided packet-generator interface
 320
 321         :param pg_interface: interface used to resolve, if None then this
 322             interface is used
 323
 324         """
 325         if pg_interface is None:
 326             pg_interface = self
 327         self.test.logger.info("Sending ARP request for %s on port %s" %
 328                               (self.local_ip4, pg_interface.name))
 329         arp_req = self.create_arp_req()
 330         pg_interface.add_stream(arp_req)
 331         pg_interface.enable_capture()
 332         self.test.pg_start()
 333         self.test.logger.info(self.test.vapi.cli("show trace"))
 334         try:
 335             captured_packet = pg_interface.wait_for_packet(1)
 336         except:
 337             self.test.logger.info("No ARP received on port %s" %
 338                                   pg_interface.name)
 339             return
 340         self.rotate_out_file()
 341         arp_reply = captured_packet.copy()  # keep original for exception
 342         # Make Dot1AD packet content recognizable to scapy
 343         if arp_reply.type == 0x88a8:
 344             arp_reply.type = 0x8100
 345             arp_reply = Ether(str(arp_reply))
 346         try:
 347             if arp_reply[ARP].op == ARP.is_at:
 348                 self.test.logger.info("VPP %s MAC address is %s " %
 349                                       (self.name, arp_reply[ARP].hwsrc))
 350                 self._local_mac = arp_reply[ARP].hwsrc
 351             else:
 352                 self.test.logger.info("No ARP received on port %s" %
 353                                       pg_interface.name)
 354         except:
 355             self.test.logger.error(
 356                 ppp("Unexpected response to ARP request:", captured_packet))
 357             raise
 358
 359     def resolve_ndp(self, pg_interface=None, timeout=1):
 360         """Resolve NDP using provided packet-generator interface
 361
 362         :param pg_interface: interface used to resolve, if None then this
 363             interface is used
 364         :param timeout: how long to wait for response before giving up
 365
 366         """
 367         if pg_interface is None:
 368             pg_interface = self
 369         self.test.logger.info("Sending NDP request for %s on port %s" %
 370                               (self.local_ip6, pg_interface.name))
 371         ndp_req = self.create_ndp_req()
 372         pg_interface.add_stream(ndp_req)
 373         pg_interface.enable_capture()
 374         self.test.pg_start()
 375         now = time.time()
 376         deadline = now + timeout
 377         # Enabling IPv6 on an interface can generate more than the
 378         # ND reply we are looking for (namely MLD). So loop through
 379         # the replies to look for want we want.
 380         while now < deadline:
 381             try:
 382                 captured_packet = pg_interface.wait_for_packet(
 383                     deadline - now, filter_out_fn=None)
 384             except:
 385                 self.test.logger.error("Timeout while waiting for NDP response")
 386                 raise
 387             ndp_reply = captured_packet.copy()  # keep original for exception
 388             # Make Dot1AD packet content recognizable to scapy
 389             if ndp_reply.type == 0x88a8:
 390                 ndp_reply.type = 0x8100
 391                 ndp_reply = Ether(str(ndp_reply))
 392             try:
 393                 ndp_na = ndp_reply[ICMPv6ND_NA]
 394                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 395                 self.test.logger.info("VPP %s MAC address is %s " %
 396                                       (self.name, opt.lladdr))
 397                 self._local_mac = opt.lladdr
 398                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 399                 # we now have the MAC we've been after
 400                 self.rotate_out_file()
 401                 return
 402             except:
 403                 self.test.logger.info(
 404                     ppp("Unexpected response to NDP request:", captured_packet))
 405             now = time.time()
 406
 407         self.test.logger.debug(self.test.vapi.cli("show trace"))
 408         self.rotate_out_file()
 409         raise Exception("Timeout while waiting for NDP response")