| import os |
| import time |
| import socket |
| import struct |
| from traceback import format_exc, format_stack |
| from scapy.utils import wrpcap, rdpcap, PcapReader |
| from scapy.plist import PacketList |
| from vpp_interface import VppInterface |
| |
| from scapy.layers.l2 import Ether, ARP |
| from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\ |
| ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \ |
| IPv6ExtHdrHopByHop |
| from util import ppp, ppc |
| from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr |
| from scapy.utils import inet_pton, inet_ntop |
| |
| |
| class CaptureTimeoutError(Exception): |
| """ Exception raised if capture or packet doesn't appear within timeout """ |
| pass |
| |
| |
| def is_ipv6_misc(p): |
| """ Is packet one of uninteresting IPv6 broadcasts? """ |
| if p.haslayer(ICMPv6ND_RA): |
| if in6_ismaddr(p[IPv6].dst): |
| return True |
| if p.haslayer(IPv6ExtHdrHopByHop): |
| for o in p[IPv6ExtHdrHopByHop].options: |
| if isinstance(o, RouterAlert): |
| return True |
| return False |
| |
| |
| class VppPGInterface(VppInterface): |
| """ |
| VPP packet-generator interface |
| """ |
| |
| @property |
| def pg_index(self): |
| """packet-generator interface index assigned by VPP""" |
| return self._pg_index |
| |
| @property |
| def out_path(self): |
| """pcap file path - captured packets""" |
| return self._out_path |
| |
| @property |
| def in_path(self): |
| """ pcap file path - injected packets""" |
| return self._in_path |
| |
| @property |
| def capture_cli(self): |
| """CLI string to start capture on this interface""" |
| return self._capture_cli |
| |
| @property |
| def cap_name(self): |
| """capture name for this interface""" |
| return self._cap_name |
| |
| @property |
| def input_cli(self): |
| """CLI string to load the injected packets""" |
| return self._input_cli |
| |
| @property |
| def in_history_counter(self): |
| """Self-incrementing counter used when renaming old pcap files""" |
| v = self._in_history_counter |
| self._in_history_counter += 1 |
| return v |
| |
| @property |
| def out_history_counter(self): |
| """Self-incrementing counter used when renaming old pcap files""" |
| v = self._out_history_counter |
| self._out_history_counter += 1 |
| return v |
| |
| def __init__(self, test, pg_index): |
| """ Create VPP packet-generator interface """ |
| r = test.vapi.pg_create_interface(pg_index) |
| self._sw_if_index = r.sw_if_index |
| |
| super(VppPGInterface, self).__init__(test) |
| |
| self._in_history_counter = 0 |
| self._out_history_counter = 0 |
| self._out_assert_counter = 0 |
| self._pg_index = pg_index |
| self._out_file = "pg%u_out.pcap" % self.pg_index |
| self._out_path = self.test.tempdir + "/" + self._out_file |
| self._in_file = "pg%u_in.pcap" % self.pg_index |
| self._in_path = self.test.tempdir + "/" + self._in_file |
| self._capture_cli = "packet-generator capture pg%u pcap %s" % ( |
| self.pg_index, self.out_path) |
| self._cap_name = "pcap%u" % self.sw_if_index |
| self._input_cli = \ |
| "packet-generator new pcap %s source pg%u name %s" % ( |
| self.in_path, self.pg_index, self.cap_name) |
| |
| def enable_capture(self): |
| """ Enable capture on this packet-generator interface""" |
| try: |
| if os.path.isfile(self.out_path): |
| name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" % \ |
| (self.test.tempdir, |
| time.time(), |
| self.name, |
| self.out_history_counter, |
| self._out_file) |
| self.test.logger.debug("Renaming %s->%s" % |
| (self.out_path, name)) |
| os.rename(self.out_path, name) |
| except: |
| pass |
| # FIXME this should be an API, but no such exists atm |
| self.test.vapi.cli(self.capture_cli) |
| self._pcap_reader = None |
| |
| def add_stream(self, pkts): |
| """ |
| Add a stream of packets to this packet-generator |
| |
| :param pkts: iterable packets |
| |
| """ |
| try: |
| if os.path.isfile(self.in_path): |
| name = "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %\ |
| (self.test.tempdir, |
| time.time(), |
| self.name, |
| self.in_history_counter, |
| self._in_file) |
| self.test.logger.debug("Renaming %s->%s" % |
| (self.in_path, name)) |
| os.rename(self.in_path, name) |
| except: |
| pass |
| wrpcap(self.in_path, pkts) |
| self.test.register_capture(self.cap_name) |
| # FIXME this should be an API, but no such exists atm |
| self.test.vapi.cli(self.input_cli) |
| |
| def generate_debug_aid(self, kind): |
| """ Create a hardlink to the out file with a counter and a file |
| containing stack trace to ease debugging in case of multiple capture |
| files present. """ |
| self.test.logger.debug("Generating debug aid for %s on %s" % |
| (kind, self._name)) |
| link_path, stack_path = ["%s/debug_%s_%s_%s.%s" % |
| (self.test.tempdir, self._name, |
| self._out_assert_counter, kind, suffix) |
| for suffix in ["pcap", "stack"] |
| ] |
| os.link(self.out_path, link_path) |
| with open(stack_path, "w") as f: |
| f.writelines(format_stack()) |
| self._out_assert_counter += 1 |
| |
| def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc): |
| """ Helper method to get capture and filter it """ |
| try: |
| if not self.wait_for_capture_file(timeout): |
| return None |
| output = rdpcap(self.out_path) |
| self.test.logger.debug("Capture has %s packets" % len(output.res)) |
| except: |
| self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" % |
| (self.out_path, format_exc())) |
| return None |
| before = len(output.res) |
| if filter_out_fn: |
| output.res = [p for p in output.res if not filter_out_fn(p)] |
| removed = before - len(output.res) |
| if removed: |
| self.test.logger.debug( |
| "Filtered out %s packets from capture (returning %s)" % |
| (removed, len(output.res))) |
| return output |
| |
| def get_capture(self, expected_count=None, remark=None, timeout=1, |
| filter_out_fn=is_ipv6_misc): |
| """ Get captured packets |
| |
| :param expected_count: expected number of packets to capture, if None, |
| then self.test.packet_count_for_dst_pg_idx is |
| used to lookup the expected count |
| :param remark: remark printed into debug logs |
| :param timeout: how long to wait for packets |
| :param filter_out_fn: filter applied to each packet, packets for which |
| the filter returns True are removed from capture |
| :returns: iterable packets |
| """ |
| remaining_time = timeout |
| capture = None |
| name = self.name if remark is None else "%s (%s)" % (self.name, remark) |
| based_on = "based on provided argument" |
| if expected_count is None: |
| expected_count = \ |
| self.test.get_packet_count_for_if_idx(self.sw_if_index) |
| based_on = "based on stored packet_infos" |
| if expected_count == 0: |
| raise Exception( |
| "Internal error, expected packet count for %s is 0!" % |
| name) |
| self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % ( |
| expected_count, based_on, name)) |
| while remaining_time > 0: |
| before = time.time() |
| capture = self._get_capture(remaining_time, filter_out_fn) |
| elapsed_time = time.time() - before |
| if capture: |
| if len(capture.res) == expected_count: |
| # bingo, got the packets we expected |
| return capture |
| else: |
| self.test.logger.debug("Partial capture containing %s " |
| "packets doesn't match expected " |
| "count %s (yet?)" % |
| (len(capture.res), expected_count)) |
| elif expected_count == 0: |
| # bingo, got None as we expected - return empty capture |
| return PacketList() |
| remaining_time -= elapsed_time |
| if capture: |
| self.generate_debug_aid("count-mismatch") |
| raise Exception("Captured packets mismatch, captured %s packets, " |
| "expected %s packets on %s" % |
| (len(capture.res), expected_count, name)) |
| else: |
| raise Exception("No packets captured on %s" % name) |
| |
| def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc): |
| """ Assert that nothing unfiltered was captured on interface |
| |
| :param remark: remark printed into debug logs |
| :param filter_out_fn: filter applied to each packet, packets for which |
| the filter returns True are removed from capture |
| """ |
| if os.path.isfile(self.out_path): |
| try: |
| capture = self.get_capture( |
| 0, remark=remark, filter_out_fn=filter_out_fn) |
| if not capture or len(capture.res) == 0: |
| # junk filtered out, we're good |
| return |
| self.test.logger.error( |
| ppc("Unexpected packets captured:", capture)) |
| except: |
| pass |
| self.generate_debug_aid("empty-assert") |
| if remark: |
| raise AssertionError( |
| "Non-empty capture file present for interface %s (%s)" % |
| (self.name, remark)) |
| else: |
| raise AssertionError("Capture file present for interface %s" % |
| self.name) |
| |
| def wait_for_capture_file(self, timeout=1): |
| """ |
| Wait until pcap capture file appears |
| |
| :param timeout: How long to wait for the packet (default 1s) |
| |
| :returns: True/False if the file is present or appears within timeout |
| """ |
| deadline = time.time() + timeout |
| if not os.path.isfile(self.out_path): |
| self.test.logger.debug("Waiting for capture file %s to appear, " |
| "timeout is %ss" % (self.out_path, timeout)) |
| else: |
| self.test.logger.debug("Capture file %s already exists" % |
| self.out_path) |
| return True |
| while time.time() < deadline: |
| if os.path.isfile(self.out_path): |
| break |
| time.sleep(0) # yield |
| if os.path.isfile(self.out_path): |
| self.test.logger.debug("Capture file appeared after %fs" % |
| (time.time() - (deadline - timeout))) |
| else: |
| self.test.logger.debug("Timeout - capture file still nowhere") |
| return False |
| return True |
| |
| def verify_enough_packet_data_in_pcap(self): |
| """ |
| Check if enough data is available in file handled by internal pcap |
| reader so that a whole packet can be read. |
| |
| :returns: True if enough data present, else False |
| """ |
| orig_pos = self._pcap_reader.f.tell() # save file position |
| enough_data = False |
| # read packet header from pcap |
| packet_header_size = 16 |
| caplen = None |
| end_pos = None |
| hdr = self._pcap_reader.f.read(packet_header_size) |
| if len(hdr) == packet_header_size: |
| # parse the capture length - caplen |
| sec, usec, caplen, wirelen = struct.unpack( |
| self._pcap_reader.endian + "IIII", hdr) |
| self._pcap_reader.f.seek(0, 2) # seek to end of file |
| end_pos = self._pcap_reader.f.tell() # get position at end |
| if end_pos >= orig_pos + len(hdr) + caplen: |
| enough_data = True # yay, we have enough data |
| self._pcap_reader.f.seek(orig_pos, 0) # restore original position |
| return enough_data |
| |
| def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc): |
| """ |
| Wait for next packet captured with a timeout |
| |
| :param timeout: How long to wait for the packet |
| |
| :returns: Captured packet if no packet arrived within timeout |
| :raises Exception: if no packet arrives within timeout |
| """ |
| deadline = time.time() + timeout |
| if self._pcap_reader is None: |
| if not self.wait_for_capture_file(timeout): |
| raise CaptureTimeoutError("Capture file %s did not appear " |
| "within timeout" % self.out_path) |
| while time.time() < deadline: |
| try: |
| self._pcap_reader = PcapReader(self.out_path) |
| break |
| except: |
| self.test.logger.debug( |
| "Exception in scapy.PcapReader(%s): %s" % |
| (self.out_path, format_exc())) |
| if not self._pcap_reader: |
| raise CaptureTimeoutError("Capture file %s did not appear within " |
| "timeout" % self.out_path) |
| |
| poll = False |
| if timeout > 0: |
| self.test.logger.debug("Waiting for packet") |
| else: |
| poll = True |
| self.test.logger.debug("Polling for packet") |
| while time.time() < deadline or poll: |
| if not self.verify_enough_packet_data_in_pcap(): |
| time.sleep(0) # yield |
| poll = False |
| continue |
| p = self._pcap_reader.recv() |
| if p is not None: |
| if filter_out_fn is not None and filter_out_fn(p): |
| self.test.logger.debug( |
| "Packet received after %ss was filtered out" % |
| (time.time() - (deadline - timeout))) |
| else: |
| self.test.logger.debug( |
| "Packet received after %fs" % |
| (time.time() - (deadline - timeout))) |
| return p |
| time.sleep(0) # yield |
| poll = False |
| self.test.logger.debug("Timeout - no packets received") |
| raise CaptureTimeoutError("Packet didn't arrive within timeout") |
| |
| def create_arp_req(self): |
| """Create ARP request applicable for this interface""" |
| return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) / |
| ARP(op=ARP.who_has, pdst=self.local_ip4, |
| psrc=self.remote_ip4, hwsrc=self.remote_mac)) |
| |
| def create_ndp_req(self): |
| """Create NDP - NS applicable for this interface""" |
| nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6)) |
| d = inet_ntop(socket.AF_INET6, nsma) |
| |
| return (Ether(dst=in6_getnsmac(nsma)) / |
| IPv6(dst=d, src=self.remote_ip6) / |
| ICMPv6ND_NS(tgt=self.local_ip6) / |
| ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac)) |
| |
| def resolve_arp(self, pg_interface=None): |
| """Resolve ARP using provided packet-generator interface |
| |
| :param pg_interface: interface used to resolve, if None then this |
| interface is used |
| |
| """ |
| if pg_interface is None: |
| pg_interface = self |
| self.test.logger.info("Sending ARP request for %s on port %s" % |
| (self.local_ip4, pg_interface.name)) |
| arp_req = self.create_arp_req() |
| pg_interface.add_stream(arp_req) |
| pg_interface.enable_capture() |
| self.test.pg_start() |
| self.test.logger.info(self.test.vapi.cli("show trace")) |
| try: |
| captured_packet = pg_interface.wait_for_packet(1) |
| except: |
| self.test.logger.info("No ARP received on port %s" % |
| pg_interface.name) |
| return |
| arp_reply = captured_packet.copy() # keep original for exception |
| # Make Dot1AD packet content recognizable to scapy |
| if arp_reply.type == 0x88a8: |
| arp_reply.type = 0x8100 |
| arp_reply = Ether(str(arp_reply)) |
| try: |
| if arp_reply[ARP].op == ARP.is_at: |
| self.test.logger.info("VPP %s MAC address is %s " % |
| (self.name, arp_reply[ARP].hwsrc)) |
| self._local_mac = arp_reply[ARP].hwsrc |
| else: |
| self.test.logger.info("No ARP received on port %s" % |
| pg_interface.name) |
| except: |
| self.test.logger.error( |
| ppp("Unexpected response to ARP request:", captured_packet)) |
| raise |
| |
| def resolve_ndp(self, pg_interface=None, timeout=1): |
| """Resolve NDP using provided packet-generator interface |
| |
| :param pg_interface: interface used to resolve, if None then this |
| interface is used |
| :param timeout: how long to wait for response before giving up |
| |
| """ |
| if pg_interface is None: |
| pg_interface = self |
| self.test.logger.info("Sending NDP request for %s on port %s" % |
| (self.local_ip6, pg_interface.name)) |
| ndp_req = self.create_ndp_req() |
| pg_interface.add_stream(ndp_req) |
| pg_interface.enable_capture() |
| self.test.pg_start() |
| now = time.time() |
| deadline = now + timeout |
| # Enabling IPv6 on an interface can generate more than the |
| # ND reply we are looking for (namely MLD). So loop through |
| # the replies to look for want we want. |
| while now < deadline: |
| try: |
| captured_packet = pg_interface.wait_for_packet( |
| deadline - now, filter_out_fn=None) |
| except: |
| self.test.logger.error( |
| "Timeout while waiting for NDP response") |
| raise |
| ndp_reply = captured_packet.copy() # keep original for exception |
| # Make Dot1AD packet content recognizable to scapy |
| if ndp_reply.type == 0x88a8: |
| ndp_reply.type = 0x8100 |
| ndp_reply = Ether(str(ndp_reply)) |
| try: |
| ndp_na = ndp_reply[ICMPv6ND_NA] |
| opt = ndp_na[ICMPv6NDOptDstLLAddr] |
| self.test.logger.info("VPP %s MAC address is %s " % |
| (self.name, opt.lladdr)) |
| self._local_mac = opt.lladdr |
| self.test.logger.debug(self.test.vapi.cli("show trace")) |
| # we now have the MAC we've been after |
| return |
| except: |
| self.test.logger.info( |
| ppp("Unexpected response to NDP request:", |
| captured_packet)) |
| now = time.time() |
| |
| self.test.logger.debug(self.test.vapi.cli("show trace")) |
| raise Exception("Timeout while waiting for NDP response") |