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