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