diff options
Diffstat (limited to 'test/vpp_pg_interface.py')
| -rw-r--r-- | test/vpp_pg_interface.py | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/test/vpp_pg_interface.py b/test/vpp_pg_interface.py new file mode 100644 index 00000000..81e9714a --- /dev/null +++ b/test/vpp_pg_interface.py @@ -0,0 +1,481 @@ +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 + elif len(capture.res) > expected_count: + self.test.logger.error( + ppc("Unexpected packets captured:", 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") + 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 + 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") |