import os import shutil import socket from socket import inet_pton, inet_ntop import struct import time from traceback import format_exc, format_stack from sh import tshark from pathlib import Path from config import config from scapy.utils import wrpcap, rdpcap, PcapReader from scapy.plist import PacketList from vpp_interface import VppInterface from vpp_papi import VppEnum 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, UnexpectedPacketError from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr 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 gso_enabled(self): """gso enabled on packet-generator interface""" if self._gso_enabled == 0: return "gso-disabled" return "gso-enabled" @property def gso_size(self): """gso size on packet-generator interface""" return self._gso_size @property def coalesce_is_enabled(self): """coalesce enabled on packet-generator interface""" if self._coalesce_enabled == 0: return "coalesce-disabled" return "coalesce-enabled" @property def out_path(self): """pcap file path - captured packets""" return self._out_path def get_in_path(self, worker): """pcap file path - injected packets""" if worker is not None: return "%s/pg%u_wrk%u_in.pcap" % (self.test.tempdir, self.pg_index, worker) return "%s/pg%u_in.pcap" % (self.test.tempdir, self.pg_index) @property def capture_cli(self): """CLI string to start capture on this interface""" return self._capture_cli def get_cap_name(self, worker=None): """return capture name for this interface and given worker""" if worker is not None: return self._cap_name + "-worker%d" % worker return self._cap_name def get_input_cli(self, nb_replays=None, worker=None): """return CLI string to load the injected packets""" input_cli = "packet-generator new pcap %s source pg%u name %s" % ( self.get_in_path(worker), self.pg_index, self.get_cap_name(worker), ) if nb_replays is not None: return "%s limit %d" % (input_cli, nb_replays) if worker is not None: return "%s worker %d" % (input_cli, worker) return 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, gso, gso_size, mode): """Create VPP packet-generator interface""" super().__init__(test) r = test.vapi.pg_create_interface_v2(pg_index, gso, gso_size, mode) self.set_sw_if_index(r.sw_if_index) self._in_history_counter = 0 self._out_history_counter = 0 self._out_assert_counter = 0 self._pg_index = pg_index self._gso_enabled = gso self._gso_size = gso_size self._coalesce_enabled = 0 self._out_file = "pg%u_out.pcap" % self.pg_index self._out_path = self.test.tempdir + "/" + self._out_file self._capture_cli = "packet-generator capture pg%u pcap %s" % ( self.pg_index, self.out_path, ) self._cap_name = "pcap%u-sw_if_index-%s" % (self.pg_index, self.sw_if_index) def link_pcap_file(self, path, direction, counter): if not config.keep_pcaps: return filename = os.path.basename(path) test_name = ( self.test_name if hasattr(self, "test_name") else f"suite{self.test.__name__}" ) name = f"{self.test.tempdir}/{test_name}.[timestamp:{time.time():.8f}].{self.name}-{direction}-{counter:04}.{filename}" if os.path.isfile(name): self.test.logger.debug( f"Skipping hard link creation: {name} already exists!" ) return try: if os.path.isfile(path): self.test.logger.debug(f"Creating hard link {path}->{name}") os.link(path, name) except OSError: self.test.logger.debug( f"OSError: Could not create hard link {path}->{name}" ) def remove_old_pcap_file(self, path): self.wait_for_pg_stop() self.test.unlink_testcase_file(self.test, Path(path)) return def decode_pcap_files(self, pcap_dir, filename_prefix): # Generate tshark packet trace of testcase pcap files pg_decode = f"{pcap_dir}/pcap-decode-{filename_prefix}.txt" if os.path.isfile(pg_decode): self.test.logger.debug( f"The pg streams decode file already exists: {pg_decode}" ) return self.test.logger.debug( f"Generating testcase pg streams decode file: {pg_decode}" ) ts_opts = "-Vxr" for p in sorted(Path(pcap_dir).glob(f"{filename_prefix}*.pcap")): self.test.logger.debug(f"Decoding {p}") with open(f"{pg_decode}", "a", buffering=1) as f: print(f"tshark {ts_opts} {p}", file=f) tshark(ts_opts, f"{p}", _out=f) print("", file=f) def enable_capture(self): """Enable capture on this packet-generator interface of at most n packets. If n < 0, this is no limit """ # disable the capture to flush the capture self.disable_capture() self.remove_old_pcap_file(self.out_path) # FIXME this should be an API, but no such exists atm self.test.vapi.cli(self.capture_cli) self._pcap_reader = None def disable_capture(self): self.test.vapi.cli("%s disable" % self.capture_cli) def coalesce_enable(self): """Enable packet coalesce on this packet-generator interface""" self._coalesce_enabled = 1 self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index, 1) def coalesce_disable(self): """Disable packet coalesce on this packet-generator interface""" self._coalesce_enabled = 0 self.test.vapi.pg_interface_enable_disable_coalesce(self.sw_if_index, 0) def add_stream(self, pkts, nb_replays=None, worker=None): """ Add a stream of packets to this packet-generator :param pkts: iterable packets """ in_pcap = self.get_in_path(worker) if os.path.isfile(in_pcap): self.remove_old_pcap_file(in_pcap) wrpcap(in_pcap, pkts) self.test.register_pcap(self, worker) # FIXME this should be an API, but no such exists atm self.test.vapi.cli(self.get_input_cli(nb_replays, worker)) self.link_pcap_file(self.get_in_path(worker), "inp", self.in_history_counter) 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(f"Capture has {len(output.res)} packets") 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 elif len(capture.res) > expected_count: self.test.logger.error( ppc( f"Unexpected packets captured, got {len(capture.res)}, expected {expected_count}:", capture, ) ) break 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") if len(capture) > 0 and 0 == expected_count: rem = f"\n{remark}" if remark else "" raise UnexpectedPacketError( capture[0], f"\n({len(capture)} packets captured in total){rem} on {name}", ) msg = f"Captured packets mismatch, captured {len(capture.res)} packets, expected {expected_count} packets on {name}:" raise Exception(f"{ppc(msg, capture)}") else: if 0 == expected_count: return raise Exception(f"No packets captured on {name} (timeout = {timeout}s)") def assert_nothing_captured( self, timeout=1, 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 """ capture = self.get_capture( 0, timeout=timeout, remark=remark, filter_out_fn=filter_out_fn ) if not capture or len(capture.res) == 0: # junk filtered out, we're good return def wait_for_pg_stop(self): # wait till packet-generator is stopped # "show packet-generator" while it is still running gives this: # Name Enabled Count Parameters # pcap0-sw_if_inde Yes 64 limit 64, ... # # also have a 5-minute timeout just in case things go terribly wrong... deadline = time.time() + 300 while self.test.vapi.cli("show packet-generator").find("Yes") != -1: self._test.sleep(0.01) # yield if time.time() > deadline: self.test.logger.debug("Timeout waiting for pg to stop") break 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 """ self.wait_for_pg_stop() deadline = time.time() + timeout if not os.path.isfile(self.out_path): self.test.logger.debug( f"Waiting for capture file {self.out_path} to appear, timeout is {timeout}s\n" f"{' '.join(format_stack(limit=10))}" ) else: self.test.logger.debug("Capture file %s already exists" % self.out_path) self.link_pcap_file(self.out_path, "out", self.out_history_counter) return True while time.time() < deadline: if os.path.isfile(self.out_path): break self._test.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 self.link_pcap_file(self.out_path, "out", self.out_history_counter) 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(): self._test.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 self._test.sleep(0) # yield poll = False self.test.logger.debug(f"Timeout ({timeout}) - no packets received") raise CaptureTimeoutError(f"Packet didn't arrive within timeout ({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, addr=None): """Create NDP - NS applicable for this interface""" if not addr: addr = self.local_ip6 nsma = in6_getnsma(inet_pton(socket.AF_INET6, addr)) d = inet_ntop(socket.AF_INET6, nsma) return ( Ether(dst=in6_getnsmac(nsma)) / IPv6(dst=d, src=self.remote_ip6) / ICMPv6ND_NS(tgt=addr) / 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 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, link_layer=False): """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 :param link_layer: resolve for global address if False (default) or for link-layer address if True """ if pg_interface is None: pg_interface = self addr = self.local_ip6_ll if link_layer else self.local_ip6 self.test.logger.info( "Sending NDP request for %s on port %s" % (addr, pg_interface.name) ) ndp_req = self.create_ndp_req(addr) 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 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")