BFD: basic asynchronous session up/down

This is a work-in-progress basic BFD session handling. Only
asynchronous mode is supported at the moment. Setting the session flags
doesn't work.

Change-Id: Idba27f721b5c35be5a66a6d202a63d23ff7ecf6f
Signed-off-by: Klement Sekera <ksekera@cisco.com>

9 files changed, 926 insertions, 190 deletions

diff --git a/test/bfd.py b/test/bfd.py
new file mode 100644
index 00000000000..beacd80f687
--- /dev/null
+++ b/test/bfd.py
@@ -0,0 +1,216 @@
+from socket import AF_INET, AF_INET6
+from scapy.all import *
+from scapy.packet import *
+from scapy.fields import *
+from framework import *
+from vpp_object import *
+from util import NumericConstant
+
+
+class BFDDiagCode(NumericConstant):
+    """ BFD Diagnostic Code """
+    no_diagnostic = 0
+    control_detection_time_expired = 1
+    echo_function_failed = 2
+    neighbor_signaled_session_down = 3
+    forwarding_plane_reset = 4
+    path_down = 5
+    concatenated_path_down = 6
+    administratively_down = 7
+    reverse_concatenated_path_down = 8
+
+    desc_dict = {
+        no_diagnostic: "No diagnostic",
+        control_detection_time_expired: "Control Detection Time Expired",
+        echo_function_failed: "Echo Function Failed",
+        neighbor_signaled_session_down: "Neighbor Signaled Session Down",
+        forwarding_plane_reset: "Forwarding Plane Reset",
+        path_down: "Path Down",
+        concatenated_path_down: "Concatenated Path Down",
+        administratively_down: "Administratively Down",
+        reverse_concatenated_path_down: "Reverse Concatenated Path Down",
+    }
+
+    def __init__(self, value):
+        NumericConstant.__init__(self, value)
+
+
+class BFDState(NumericConstant):
+    """ BFD State """
+    admin_down = 0
+    down = 1
+    init = 2
+    up = 3
+
+    desc_dict = {
+        admin_down: "AdminDown",
+        down: "Down",
+        init: "Init",
+        up: "Up",
+    }
+
+    def __init__(self, value):
+        NumericConstant.__init__(self, value)
+
+
+class BFD(Packet):
+
+    udp_dport = 3784  #: BFD destination port per RFC 5881
+    udp_sport_min = 49152  #: BFD source port min value per RFC 5881
+    udp_sport_max = 65535  #: BFD source port max value per RFC 5881
+
+    name = "BFD"
+
+    fields_desc = [
+        BitField("version", 1, 3),
+        BitEnumField("diag", 0, 5, BFDDiagCode.desc_dict),
+        BitEnumField("state", 0, 2, BFDState.desc_dict),
+        FlagsField("flags", 0, 6, ['P', 'F', 'C', 'A', 'D', 'M']),
+        XByteField("detect_mult", 0),
+        XByteField("length", 24),
+        BitField("my_discriminator", 0, 32),
+        BitField("your_discriminator", 0, 32),
+        BitField("desired_min_tx_interval", 0, 32),
+        BitField("required_min_rx_interval", 0, 32),
+        BitField("required_min_echo_rx_interval", 0, 32)]
+
+    def mysummary(self):
+        return self.sprintf("BFD(my_disc=%BFD.my_discriminator%,"
+                            "your_disc=%BFD.your_discriminator%)")
+
+# glue the BFD packet class to scapy parser
+bind_layers(UDP, BFD, dport=BFD.udp_dport)
+
+
+class VppBFDUDPSession(VppObject):
+    """ Represents BFD UDP session in VPP """
+
+    @property
+    def test(self):
+        """ Test which created this session """
+        return self._test
+
+    @property
+    def interface(self):
+        """ Interface on which this session lives """
+        return self._interface
+
+    @property
+    def af(self):
+        """ Address family - AF_INET or AF_INET6 """
+        return self._af
+
+    @property
+    def bs_index(self):
+        """ BFD session index from VPP """
+        if self._bs_index is not None:
+            return self._bs_index
+        raise NotConfiguredException("not configured")
+
+    @property
+    def local_addr(self):
+        """ BFD session local address (VPP address) """
+        if self._local_addr is None:
+            return self._interface.local_ip4
+        return self._local_addr
+
+    @property
+    def local_addr_n(self):
+        """ BFD session local address (VPP address) - raw, suitable for API """
+        if self._local_addr is None:
+            return self._interface.local_ip4n
+        return self._local_addr_n
+
+    @property
+    def peer_addr(self):
+        """ BFD session peer address """
+        return self._peer_addr
+
+    @property
+    def peer_addr_n(self):
+        """ BFD session peer address - raw, suitable for API """
+        return self._peer_addr_n
+
+    @property
+    def state(self):
+        """ BFD session state """
+        result = self.test.vapi.bfd_udp_session_dump()
+        session = None
+        for s in result:
+            if s.sw_if_index == self.interface.sw_if_index:
+                if self.af == AF_INET \
+                        and s.is_ipv6 == 0 \
+                        and self.interface.local_ip4n == s.local_addr[:4] \
+                        and self.interface.remote_ip4n == s.peer_addr[:4]:
+                    session = s
+                    break
+        if session is None:
+            raise Exception(
+                "Could not find BFD session in VPP response: %s" % repr(result))
+        return session.state
+
+    @property
+    def desired_min_tx(self):
+        return self._desired_min_tx
+
+    @property
+    def required_min_rx(self):
+        return self._required_min_rx
+
+    @property
+    def detect_mult(self):
+        return self._detect_mult
+
+    def __init__(self, test, interface, peer_addr, local_addr=None, af=AF_INET):
+        self._test = test
+        self._interface = interface
+        self._af = af
+        self._local_addr = local_addr
+        self._peer_addr = peer_addr
+        self._peer_addr_n = socket.inet_pton(af, peer_addr)
+        self._bs_index = None
+        self._desired_min_tx = 200000  # 0.2s
+        self._required_min_rx = 200000  # 0.2s
+        self._detect_mult = 3  # 3 packets need to be missed
+
+    def add_vpp_config(self):
+        is_ipv6 = 1 if AF_INET6 == self.af else 0
+        result = self.test.vapi.bfd_udp_add(
+            self._interface.sw_if_index,
+            self.desired_min_tx,
+            self.required_min_rx,
+            self.detect_mult,
+            self.local_addr_n,
+            self.peer_addr_n,
+            is_ipv6=is_ipv6)
+        self._bs_index = result.bs_index
+
+    def query_vpp_config(self):
+        result = self.test.vapi.bfd_udp_session_dump()
+        session = None
+        for s in result:
+            if s.sw_if_index == self.interface.sw_if_index:
+                if self.af == AF_INET \
+                        and s.is_ipv6 == 0 \
+                        and self.interface.local_ip4n == s.local_addr[:4] \
+                        and self.interface.remote_ip4n == s.peer_addr[:4]:
+                    session = s
+                    break
+        if session is None:
+            return False
+        return True
+
+    def remove_vpp_config(self):
+        if hasattr(self, '_bs_index'):
+            is_ipv6 = 1 if AF_INET6 == self._af else 0
+            self.test.vapi.bfd_udp_del(
+                self._interface.sw_if_index,
+                self.local_addr_n,
+                self.peer_addr_n,
+                is_ipv6=is_ipv6)
+
+    def object_id(self):
+        return "bfd-udp-%d" % self.bs_index
+
+    def admin_up(self):
+        self.test.vapi.bfd_session_set_flags(self.bs_index, 1)
diff --git a/test/framework.py b/test/framework.py
index b3cbb08a4b5..aa4f2fdf8fc 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -462,6 +462,34 @@ class VppTestCase(unittest.TestCase):
             if info.dst == dst_index:
                 return info
 
+    def assert_equal(self, real_value, expected_value, name_or_class=None):
+        if name_or_class is None:
+            self.assertEqual(real_value, expected_value, msg)
+            return
+        try:
+            msg = "Invalid %s: %d('%s') does not match expected value %d('%s')"
+            msg = msg % (getdoc(name_or_class).strip(),
+                         real_value, str(name_or_class(real_value)),
+                         expected_value, str(name_or_class(expected_value)))
+        except:
+            msg = "Invalid %s: %s does not match expected value %s" % (
+                name_or_class, real_value, expected_value)
+
+        self.assertEqual(real_value, expected_value, msg)
+
+    def assert_in_range(
+            self,
+            real_value,
+            expected_min,
+            expected_max,
+            name=None):
+        if name is None:
+            msg = None
+        else:
+            msg = "Invalid %s: %s out of range <%s,%s>" % (
+                name, real_value, expected_min, expected_max)
+        self.assertTrue(expected_min <= real_value <= expected_max, msg)
+
 
 class VppTestResult(unittest.TestResult):
     """
diff --git a/test/hook.py b/test/hook.py
index 90e9bbf56b0..f3e5f8808bd 100644
--- a/test/hook.py
+++ b/test/hook.py
@@ -100,9 +100,13 @@ class PollHook(Hook):
             signaldict = dict(
                 (k, v) for v, k in reversed(sorted(signal.__dict__.items()))
                 if v.startswith('SIG') and not v.startswith('SIG_'))
+
+            if self.testcase.vpp.returncode in signaldict:
+                s = signaldict[abs(self.testcase.vpp.returncode)]
+            else:
+                s = "unknown"
             msg = "VPP subprocess died unexpectedly with returncode %d [%s]" % (
-                self.testcase.vpp.returncode,
-                signaldict[abs(self.testcase.vpp.returncode)])
+                self.testcase.vpp.returncode, s)
             self.logger.critical(msg)
             core_path = self.testcase.tempdir + '/core'
             if os.path.isfile(core_path):
@@ -110,27 +114,27 @@ class PollHook(Hook):
             self.testcase.vpp_dead = True
             raise VppDiedError(msg)
 
-    def after_api(self, api_name, api_args):
+    def before_api(self, api_name, api_args):
         """
-        Check if VPP died after executing an API
+        Check if VPP died before executing an API
 
         :param api_name: name of the API
         :param api_args: tuple containing the API arguments
         :raises VppDiedError: exception if VPP is not running anymore
 
         """
-        super(PollHook, self).after_api(api_name, api_args)
+        super(PollHook, self).before_api(api_name, api_args)
         self.poll_vpp()
 
-    def after_cli(self, cli):
+    def before_cli(self, cli):
         """
-        Check if VPP died after executing a CLI
+        Check if VPP died before executing a CLI
 
         :param cli: CLI string
         :raises Exception: exception if VPP is not running anymore
 
         """
-        super(PollHook, self).after_cli(cli)
+        super(PollHook, self).before_cli(cli)
         self.poll_vpp()
 
 
diff --git a/test/template_bd.py b/test/template_bd.py
index 6c6fb3da200..01e8b855004 100644
--- a/test/template_bd.py
+++ b/test/template_bd.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-from abc import abstractmethod
+from abc import abstractmethod, ABCMeta
 
 from scapy.layers.l2 import Ether, Raw
 from scapy.layers.inet import IP, UDP
@@ -8,6 +8,7 @@ from scapy.layers.inet import IP, UDP
 
 class BridgeDomain(object):
     """ Bridge domain abstraction """
+    __metaclass__ = ABCMeta
 
     @property
     def frame_pg0_to_pg1(self):
diff --git a/test/test_bfd.py b/test/test_bfd.py
new file mode 100644
index 00000000000..20d3aea5e0c
--- /dev/null
+++ b/test/test_bfd.py
@@ -0,0 +1,273 @@
+#!/usr/bin/env python
+
+import unittest
+import time
+from random import randint
+from bfd import *
+from framework import *
+from util import ppp
+
+
+class BFDCLITestCase(VppTestCase):
+    """Bidirectional Forwarding Detection (BFD) - CLI"""
+
+    @classmethod
+    def setUpClass(cls):
+        super(BFDCLITestCase, cls).setUpClass()
+
+        try:
+            cls.create_pg_interfaces([0])
+            cls.pg0.config_ip4()
+            cls.pg0.resolve_arp()
+
+        except Exception:
+            super(BFDCLITestCase, cls).tearDownClass()
+            raise
+
+    def test_add_bfd(self):
+        """ create a BFD session """
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
+        session.add_vpp_config()
+        self.logger.debug("Session state is %s" % str(session.state))
+        session.remove_vpp_config()
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
+        session.add_vpp_config()
+        self.logger.debug("Session state is %s" % str(session.state))
+        session.remove_vpp_config()
+
+    def test_double_add(self):
+        """ create the same BFD session twice (negative case) """
+        session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
+        session.add_vpp_config()
+        try:
+            session.add_vpp_config()
+        except:
+            session.remove_vpp_config()
+            return
+        session.remove_vpp_config()
+        raise Exception("Expected failure while adding duplicate "
+                        "configuration")
+
+
+def create_packet(interface, ttl=255, src_port=50000, **kwargs):
+    p = (Ether(src=interface.remote_mac, dst=interface.local_mac) /
+         IP(src=interface.remote_ip4, dst=interface.local_ip4, ttl=ttl) /
+         UDP(sport=src_port, dport=BFD.udp_dport) /
+         BFD(*kwargs))
+    return p
+
+
+def verify_ip(test, packet, local_ip, remote_ip):
+    """ Verify correctness of IP layer. """
+    ip = packet[IP]
+    test.assert_equal(ip.src, local_ip, "IP source address")
+    test.assert_equal(ip.dst, remote_ip, "IP destination address")
+    test.assert_equal(ip.ttl, 255, "IP TTL")
+
+
+def verify_udp(test, packet):
+    """ Verify correctness of UDP layer. """
+    udp = packet[UDP]
+    test.assert_equal(udp.dport, BFD.udp_dport, "UDP destination port")
+    test.assert_in_range(udp.sport, BFD.udp_sport_min, BFD.udp_sport_max,
+                         "UDP source port")
+
+
+class BFDTestSession(object):
+
+    def __init__(self, test, interface, detect_mult=3):
+        self.test = test
+        self.interface = interface
+        self.bfd_values = {
+            'my_discriminator': 0,
+            'desired_min_tx_interval': 500000,
+            'detect_mult': detect_mult,
+            'diag': BFDDiagCode.no_diagnostic,
+        }
+
+    def update(self, **kwargs):
+        self.bfd_values.update(kwargs)
+
+    def create_packet(self):
+        packet = create_packet(self.interface)
+        for name, value in self.bfd_values.iteritems():
+            packet[BFD].setfieldval(name, value)
+        return packet
+
+    def send_packet(self):
+        p = self.create_packet()
+        self.test.logger.debug(ppp("Sending packet:", p))
+        self.test.pg0.add_stream([p])
+        self.test.pg_start()
+
+    def verify_packet(self, packet):
+        """ Verify correctness of BFD layer. """
+        bfd = packet[BFD]
+        self.test.assert_equal(bfd.version, 1, "BFD version")
+        self.test.assert_equal(bfd.your_discriminator,
+                               self.bfd_values['my_discriminator'],
+                               "BFD - your discriminator")
+
+
+class BFDTestCase(VppTestCase):
+    """Bidirectional Forwarding Detection (BFD)"""
+
+    @classmethod
+    def setUpClass(cls):
+        super(BFDTestCase, cls).setUpClass()
+        try:
+            cls.create_pg_interfaces([0, 1])
+            cls.pg0.config_ip4()
+            cls.pg0.generate_remote_hosts()
+            cls.pg0.configure_ipv4_neighbors()
+            cls.pg0.admin_up()
+            cls.pg0.resolve_arp()
+
+        except Exception:
+            super(BFDTestCase, cls).tearDownClass()
+            raise
+
+    def setUp(self):
+        self.vapi.want_bfd_events()
+        self.vpp_session = VppBFDUDPSession(self, self.pg0, self.pg0.remote_ip4)
+        self.vpp_session.add_vpp_config()
+        self.vpp_session.admin_up()
+        self.test_session = BFDTestSession(self, self.pg0)
+
+    def tearDown(self):
+        self.vapi.want_bfd_events(enable_disable=0)
+        if not self.vpp_dead:
+            self.vpp_session.remove_vpp_config()
+        super(BFDTestCase, self).tearDown()
+
+    def verify_event(self, event, expected_state):
+        """ Verify correctness of event values. """
+        e = event
+        self.logger.debug("Event: %s" % repr(e))
+        self.assert_equal(e.bs_index, self.vpp_session.bs_index,
+                          "BFD session index")
+        self.assert_equal(e.sw_if_index, self.vpp_session.interface.sw_if_index,
+                          "BFD interface index")
+        is_ipv6 = 0
+        if self.vpp_session.af == AF_INET6:
+            is_ipv6 = 1
+        self.assert_equal(e.is_ipv6, is_ipv6, "is_ipv6")
+        if self.vpp_session.af == AF_INET:
+            self.assert_equal(e.local_addr[:4], self.vpp_session.local_addr_n,
+                              "Local IPv4 address")
+            self.assert_equal(e.peer_addr[:4], self.vpp_session.peer_addr_n,
+                              "Peer IPv4 address")
+        else:
+            self.assert_equal(e.local_addr, self.vpp_session.local_addr_n,
+                              "Local IPv6 address")
+            self.assert_equal(e.peer_addr, self.vpp_session.peer_addr_n,
+                              "Peer IPv6 address")
+        self.assert_equal(e.state, expected_state, BFDState)
+
+    def wait_for_bfd_packet(self, timeout=1):
+        p = self.pg0.wait_for_packet(timeout=timeout)
+        bfd = p[BFD]
+        if bfd is None:
+            raise Exception(ppp("Unexpected or invalid BFD packet:", p))
+        if bfd.payload:
+            raise Exception(ppp("Unexpected payload in BFD packet:", bfd))
+        verify_ip(self, p, self.pg0.local_ip4, self.pg0.remote_ip4)
+        verify_udp(self, p)
+        self.test_session.verify_packet(p)
+        return p
+
+    def test_slow_timer(self):
+        """ Slow timer """
+
+        self.pg_enable_capture([self.pg0])
+        expected_packets = 10
+        self.logger.info("Waiting for %d BFD packets" % expected_packets)
+        self.wait_for_bfd_packet()
+        for i in range(expected_packets):
+            before = time.time()
+            self.wait_for_bfd_packet()
+            after = time.time()
+            self.assert_in_range(
+                after - before, 0.75, 1, "time between slow packets")
+            before = after
+
+    def test_zero_remote_min_rx(self):
+        """ Zero RemoteMinRxInterval """
+        self.pg_enable_capture([self.pg0])
+        p = self.wait_for_bfd_packet()
+        self.test_session.update(my_discriminator=randint(0, 40000000),
+                                 your_discriminator=p[BFD].my_discriminator,
+                                 state=BFDState.init,
+                                 required_min_rx_interval=0)
+        self.test_session.send_packet()
+        e = self.vapi.wait_for_event(1, "bfd_udp_session_details")
+        self.verify_event(e, expected_state=BFDState.up)
+
+        try:
+            p = self.pg0.wait_for_packet(timeout=1)
+        except:
+            return
+        raise Exception(ppp("Received unexpected BFD packet:", p))
+
+    def bfd_conn_up(self):
+        self.pg_enable_capture([self.pg0])
+        self.logger.info("Waiting for slow hello")
+        p = self.wait_for_bfd_packet()
+        self.logger.info("Sending Init")
+        self.test_session.update(my_discriminator=randint(0, 40000000),
+                                 your_discriminator=p[BFD].my_discriminator,
+                                 state=BFDState.init,
+                                 required_min_rx_interval=500000)
+        self.test_session.send_packet()
+        self.logger.info("Waiting for event")
+        e = self.vapi.wait_for_event(1, "bfd_udp_session_details")
+        self.verify_event(e, expected_state=BFDState.up)
+        self.logger.info("Session is Up")
+        self.test_session.update(state=BFDState.up)
+
+    def test_conn_up(self):
+        """ Basic connection up """
+        self.bfd_conn_up()
+
+    def test_hold_up(self):
+        """ Hold BFD up """
+        self.bfd_conn_up()
+        for i in range(5):
+            self.wait_for_bfd_packet()
+            self.test_session.send_packet()
+
+    def test_conn_down(self):
+        """ Session down after inactivity """
+        self.bfd_conn_up()
+        self.wait_for_bfd_packet()
+        self.assert_equal(
+            0, len(self.vapi.collect_events()),
+            "number of bfd events")
+        self.wait_for_bfd_packet()
+        self.assert_equal(
+            0, len(self.vapi.collect_events()),
+            "number of bfd events")
+        e = self.vapi.wait_for_event(1, "bfd_udp_session_details")
+        self.verify_event(e, expected_state=BFDState.down)
+
+    @unittest.skip("this test is not working yet")
+    def test_large_required_min_rx(self):
+        self.bfd_conn_up()
+        interval = 5000000
+        self.test_session.update(required_min_rx_interval=interval)
+        self.test_session.send_packet()
+        now = time.time()
+        count = 1
+        while time.time() < now + interval / 1000000:
+            try:
+                p = self.wait_for_bfd_packet()
+                if count > 1:
+                    self.logger.error(ppp("Received unexpected packet:", p))
+                count += 1
+            except:
+                pass
+        self.assert_equal(count, 1, "number of packets received")
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)
diff --git a/test/util.py b/test/util.py
index 643377f5740..f6c6acd41e9 100644
--- a/test/util.py
+++ b/test/util.py
@@ -1,5 +1,6 @@
 import socket
 import sys
+from abc import abstractmethod, ABCMeta
 from cStringIO import StringIO
 
 
@@ -14,6 +15,27 @@ def ppp(headline, packet):
     return o.getvalue()
 
 
+class NumericConstant(object):
+    __metaclass__ = ABCMeta
+
+    desc_dict = {}
+
+    @abstractmethod
+    def __init__(self, value):
+        self._value = value
+
+    def __int__(self):
+        return self._value
+
+    def __long__(self):
+        return self._value
+
+    def __str__(self):
+        if self._value in self.desc_dict:
+            return self.desc_dict[self._value]
+        return ""
+
+
 class Host(object):
     """ Generic test host "connected" to VPPs interface. """
 
diff --git a/test/vpp_object.py b/test/vpp_object.py
new file mode 100644
index 00000000000..2b71fc1fd39
--- /dev/null
+++ b/test/vpp_object.py
@@ -0,0 +1,79 @@
+from abc import ABCMeta, abstractmethod
+
+
+class VppObject(object):
+    """ Abstract vpp object """
+    __metaclass__ = ABCMeta
+
+    def __init__(self):
+        VppObjectRegistry().register(self)
+
+    @abstractmethod
+    def add_vpp_config(self):
+        """ Add the configuration for this object to vpp. """
+        pass
+
+    @abstractmethod
+    def query_vpp_config(self):
+        """Query the vpp configuration.
+
+        :return: True if the object is configured"""
+        pass
+
+    @abstractmethod
+    def remove_vpp_config(self):
+        """ Remove the configuration for this object from vpp. """
+        pass
+
+    @abstractmethod
+    def object_id(self):
+        """ Return a unique string representing this object. """
+        pass
+
+
+class VppObjectRegistry(object):
+    """ Class which handles automatic configuration cleanup. """
+    _shared_state = {}
+
+    def __init__(self):
+        self.__dict__ = self._shared_state
+        if not hasattr(self, "_object_registry"):
+            self._object_registry = []
+        if not hasattr(self, "_object_dict"):
+            self._object_dict = dict()
+
+    def register(self, o):
+        """ Register an object in the registry. """
+        if not o.unique_id() in self._object_dict:
+            self._object_registry.append(o)
+            self._object_dict[o.unique_id()] = o
+        else:
+            print "not adding duplicate %s" % o
+
+    def remove_vpp_config(self, logger):
+        """
+        Remove configuration (if present) from vpp and then remove all objects
+        from the registry.
+        """
+        if not self._object_registry:
+            logger.info("No objects registered for auto-cleanup.")
+            return
+        logger.info("Removing VPP configuration for registered objects")
+        for o in reversed(self._object_registry):
+            if o.query_vpp_config():
+                logger.info("Removing %s", o)
+                o.remove_vpp_config()
+            else:
+                logger.info("Skipping %s, configuration not present", o)
+        failed = []
+        for o in self._object_registry:
+            if o.query_vpp_config():
+                failed.append(o)
+        self._object_registry = []
+        self._object_dict = dict()
+        if failed:
+            logger.error("Couldn't remove configuration for object(s):")
+            for x in failed:
+                logger.error(repr(x))
+            raise Exception("Couldn't remove configuration for object(s): %s" %
+                            (", ".join(str(x) for x in failed)))
diff --git a/test/vpp_papi_provider.py b/test/vpp_papi_provider.py
index 2f931803e14..5e80a03e2c5 100644
--- a/test/vpp_papi_provider.py
+++ b/test/vpp_papi_provider.py
@@ -1,7 +1,12 @@
-import os, fnmatch
-import array
+import os
+import fnmatch
+import time
 from hook import Hook
 
+# Sphinx creates auto-generated documentation by importing the python source
+# files and collecting the docstrings from them. The NO_VPP_PAPI flag allows the
+# vpp_papi_provider.py file to be importable without having to build the whole
+# vpp api if the user only wishes to generate the test documentation.
 do_import = True
 try:
     no_vpp_papi = os.getenv("NO_VPP_PAPI")
@@ -17,9 +22,11 @@ if do_import:
 MPLS_IETF_MAX_LABEL = 0xfffff
 MPLS_LABEL_INVALID = MPLS_IETF_MAX_LABEL + 1
 
+
 class L2_VTR_OP:
     L2_POP_1 = 3
 
+
 class VppPapiProvider(object):
     """VPP-api provider using vpp-papi
 
@@ -35,12 +42,13 @@ class VppPapiProvider(object):
         self.test_class = test_class
         jsonfiles = []
 
-        install_dir=os.getenv('VPP_TEST_INSTALL_PATH')
+        install_dir = os.getenv('VPP_TEST_INSTALL_PATH')
         for root, dirnames, filenames in os.walk(install_dir):
             for filename in fnmatch.filter(filenames, '*.api.json'):
                 jsonfiles.append(os.path.join(root, filename))
 
         self.papi = VPP(jsonfiles)
+        self._events = list()
 
     def register_hook(self, hook):
         """Replace hook registration with new hook
@@ -50,9 +58,35 @@ class VppPapiProvider(object):
         """
         self.hook = hook
 
+    def collect_events(self):
+        e = self._events
+        self._events = list()
+        return e
+
+    def wait_for_event(self, timeout, name=None):
+        limit = time.time() + timeout
+        while time.time() < limit:
+            if self._events:
+                e = self._events.pop(0)
+                if name and type(e).__name__ != name:
+                    raise Exception(
+                        "Unexpected event received: %s, expected: %s" %
+                        (type(e).__name__, name))
+                return e
+            time.sleep(0)  # yield
+        if name is not None:
+            raise Exception("Event %s did not occur within timeout" % name)
+        raise Exception("Event did not occur within timeout")
+
+    def __call__(self, name, event):
+        # FIXME use the name instead of relying on type(e).__name__ ?
+        # FIXME #2 if this throws, it is eaten silently, Ole?
+        self._events.append(event)
+
     def connect(self):
         """Connect the API to VPP"""
         self.papi.connect(self.name, self.shm_prefix)
+        self.papi.register_event_callback(self)
 
     def disconnect(self):
         """Disconnect the API from VPP"""
@@ -73,7 +107,7 @@ class VppPapiProvider(object):
         if hasattr(reply, 'retval') and reply.retval != expected_retval:
             msg = "API call failed, expected retval == %d, got %s" % (
                 expected_retval, repr(reply))
-            self.test_class.test_instance.logger.error(msg)
+            self.test_class.logger.error(msg)
             raise Exception(msg)
         self.hook.after_api(api_fn.__name__, api_args)
         return reply
@@ -116,7 +150,7 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.pg_create_interface,
-                        { "interface_id" : pg_index })
+                        {"interface_id": pg_index})
 
     def sw_interface_dump(self, filter=None):
         """
@@ -125,7 +159,7 @@ class VppPapiProvider(object):
 
         """
         if filter is not None:
-            args = {"name_filter_valid" : 1, "name_filter" : filter}
+            args = {"name_filter_valid": 1, "name_filter": filter}
         else:
             args = {}
         return self.api(self.papi.sw_interface_dump, args)
@@ -140,8 +174,8 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_set_table,
-                        { 'sw_if_index' : sw_if_index, 'is_ipv6' : is_ipv6,
-                          'vrf_id' : table_id})
+                        {'sw_if_index': sw_if_index, 'is_ipv6': is_ipv6,
+                         'vrf_id': table_id})
 
     def sw_interface_add_del_address(self, sw_if_index, addr, addr_len,
                                      is_ipv6=0, is_add=1, del_all=0):
@@ -156,12 +190,12 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_add_del_address,
-                        { 'sw_if_index' : sw_if_index,
-                          'is_add' : is_add,
-                          'is_ipv6' : is_ipv6,
-                          'del_all' : del_all,
-                          'address_length' : addr_len,
-                          'address' : addr})
+                        {'sw_if_index': sw_if_index,
+                         'is_add': is_add,
+                         'is_ipv6': is_ipv6,
+                         'del_all': del_all,
+                         'address_length': addr_len,
+                         'address': addr})
 
     def sw_interface_enable_disable_mpls(self, sw_if_index,
                                          is_enable=1):
@@ -172,12 +206,12 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_set_mpls_enable,
-                        {'sw_if_index' : sw_if_index,
-                         'enable' : is_enable })
+                        {'sw_if_index': sw_if_index,
+                         'enable': is_enable})
 
     def sw_interface_ra_suppress(self, sw_if_index):
         return self.api(self.papi.sw_interface_ip6nd_ra_config,
-                        {'sw_if_index' : sw_if_index })
+                        {'sw_if_index': sw_if_index})
 
     def vxlan_add_del_tunnel(
             self,
@@ -202,14 +236,14 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.vxlan_add_del_tunnel,
-                        {'is_add' : is_add,
-                         'is_ipv6' : is_ipv6,
-                         'src_address' : src_addr,
-                         'dst_address' : dst_addr,
-                         'mcast_sw_if_index' : mcast_sw_if_index,
-			 'encap_vrf_id' : encap_vrf_id,
-                         'decap_next_index' : decap_next_index,
-                         'vni' : vni})
+                        {'is_add': is_add,
+                         'is_ipv6': is_ipv6,
+                         'src_address': src_addr,
+                         'dst_address': dst_addr,
+                         'mcast_sw_if_index': mcast_sw_if_index,
+                         'encap_vrf_id': encap_vrf_id,
+                         'decap_next_index': decap_next_index,
+                         'vni': vni})
 
     def bridge_domain_add_del(self, bd_id, flood=1, uu_flood=1, forward=1,
                               learn=1, arp_term=0, is_add=1):
@@ -229,13 +263,13 @@ class VppPapiProvider(object):
         :param int is_add: Add or delete flag. (Default value = 1)
         """
         return self.api(self.papi.bridge_domain_add_del,
-                        { 'bd_id' : bd_id,
-                          'flood' : flood,
-                          'uu_flood' : uu_flood,
-                          'forward' : forward,
-                          'learn' : learn,
-                          'arp_term' : arp_term,
-                          'is_add' : is_add})
+                        {'bd_id': bd_id,
+                         'flood': flood,
+                         'uu_flood': uu_flood,
+                         'forward': forward,
+                         'learn': learn,
+                         'arp_term': arp_term,
+                         'is_add': is_add})
 
     def l2fib_add_del(self, mac, bd_id, sw_if_index, is_add=1, static_mac=0,
                       filter_mac=0, bvi_mac=0):
@@ -254,13 +288,13 @@ class VppPapiProvider(object):
             interface. (Default value = 0)
         """
         return self.api(self.papi.l2fib_add_del,
-                        { 'mac' : self._convert_mac(mac),
-                          'bd_id' : bd_id,
-                          'sw_if_index' : sw_if_index,
-                          'is_add' : is_add,
-                          'static_mac' : static_mac,
-                          'filter_mac' : filter_mac,
-                          'bvi_mac' : bvi_mac })
+                        {'mac': self._convert_mac(mac),
+                         'bd_id': bd_id,
+                         'sw_if_index': sw_if_index,
+                         'is_add': is_add,
+                         'static_mac': static_mac,
+                         'filter_mac': filter_mac,
+                         'bvi_mac': bvi_mac})
 
     def sw_interface_set_l2_bridge(self, sw_if_index, bd_id,
                                    shg=0, bvi=0, enable=1):
@@ -274,11 +308,11 @@ class VppPapiProvider(object):
         :param int enable: Add or remove interface. (Default value = 1)
         """
         return self.api(self.papi.sw_interface_set_l2_bridge,
-                        { 'rx_sw_if_index' : sw_if_index,
-                          'bd_id' : bd_id,
-                          'shg' : shg,
-                          'bvi' : bvi,
-                          'enable' : enable })
+                        {'rx_sw_if_index': sw_if_index,
+                         'bd_id': bd_id,
+                         'shg': shg,
+                         'bvi': bvi,
+                         'enable': enable})
 
     def bridge_flags(self, bd_id, is_set, feature_bitmap):
         """Enable/disable required feature of the bridge domain with defined ID.
@@ -293,9 +327,9 @@ class VppPapiProvider(object):
             - arp-term (1 << 4).
         """
         return self.api(self.papi.bridge_flags,
-                        {'bd_id' : bd_id,
-                         'is_set' : is_set,
-                         'feature_bitmap' : feature_bitmap })
+                        {'bd_id': bd_id,
+                         'is_set': is_set,
+                         'feature_bitmap': feature_bitmap})
 
     def bridge_domain_dump(self, bd_id=0):
         """
@@ -305,7 +339,7 @@ class VppPapiProvider(object):
         :return: Dictionary of bridge domain(s) data.
         """
         return self.api(self.papi.bridge_domain_dump,
-                        {'bd_id' : bd_id })
+                        {'bd_id': bd_id})
 
     def sw_interface_set_l2_xconnect(self, rx_sw_if_index, tx_sw_if_index,
                                      enable):
@@ -319,11 +353,17 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_set_l2_xconnect,
-                        { 'rx_sw_if_index' : rx_sw_if_index,
-                          'tx_sw_if_index' : tx_sw_if_index,
-                          'enable' : enable })
+                        {'rx_sw_if_index': rx_sw_if_index,
+                         'tx_sw_if_index': tx_sw_if_index,
+                         'enable': enable})
 
-    def sw_interface_set_l2_tag_rewrite(self, sw_if_index, vtr_oper, push=0, tag1=0, tag2=0):
+    def sw_interface_set_l2_tag_rewrite(
+            self,
+            sw_if_index,
+            vtr_oper,
+            push=0,
+            tag1=0,
+            tag2=0):
         """L2 interface vlan tag rewrite configure request
         :param client_index - opaque cookie to identify the sender
         :param context - sender context, to match reply w/ request
@@ -335,11 +375,11 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.l2_interface_vlan_tag_rewrite,
-                        { 'sw_if_index' : sw_if_index,
-                          'vtr_op' : vtr_oper,
-                          'push_dot1q' : push,
-                          'tag1' : tag1,
-                          'tag2' : tag2 })
+                        {'sw_if_index': sw_if_index,
+                         'vtr_op': vtr_oper,
+                         'push_dot1q': push,
+                         'tag1': tag1,
+                         'tag2': tag2})
 
     def sw_interface_set_flags(self, sw_if_index, admin_up_down,
                                link_up_down=0, deleted=0):
@@ -352,10 +392,10 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_set_flags,
-                        { 'sw_if_index' : sw_if_index,
-                          'admin_up_down' : admin_up_down,
-                          'link_up_down' : link_up_down,
-                          'deleted' : deleted })
+                        {'sw_if_index': sw_if_index,
+                         'admin_up_down': admin_up_down,
+                         'link_up_down': link_up_down,
+                         'deleted': deleted})
 
     def create_subif(self, sw_if_index, sub_id, outer_vlan, inner_vlan,
                      no_tags=0, one_tag=0, two_tags=0, dot1ad=0, exact_match=0,
@@ -379,18 +419,18 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.create_subif,
-            { 'sw_if_index' : sw_if_index,
-              'sub_id' : sub_id,
-              'no_tags' : no_tags,
-              'one_tag' : one_tag,
-              'two_tags' : two_tags,
-              'dot1ad' : dot1ad,
-              'exact_match' : exact_match,
-              'default_sub' : default_sub,
-              'outer_vlan_id_any' : outer_vlan_id_any,
-              'inner_vlan_id_any' : inner_vlan_id_any,
-              'outer_vlan_id' : outer_vlan,
-              'inner_vlan_id' : inner_vlan })
+            {'sw_if_index': sw_if_index,
+             'sub_id': sub_id,
+             'no_tags': no_tags,
+             'one_tag': one_tag,
+             'two_tags': two_tags,
+             'dot1ad': dot1ad,
+             'exact_match': exact_match,
+             'default_sub': default_sub,
+             'outer_vlan_id_any': outer_vlan_id_any,
+             'inner_vlan_id_any': inner_vlan_id_any,
+             'outer_vlan_id': outer_vlan,
+             'inner_vlan_id': inner_vlan})
 
     def delete_subif(self, sw_if_index):
         """Delete subinterface
@@ -398,7 +438,7 @@ class VppPapiProvider(object):
         :param sw_if_index:
         """
         return self.api(self.papi.delete_subif,
-                        { 'sw_if_index' : sw_if_index })
+                        {'sw_if_index': sw_if_index})
 
     def create_vlan_subif(self, sw_if_index, vlan):
         """
@@ -408,8 +448,8 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.create_vlan_subif,
-                        {'sw_if_index' : sw_if_index,
-                         'vlan_id' : vlan })
+                        {'sw_if_index': sw_if_index,
+                         'vlan_id': vlan})
 
     def create_loopback(self, mac=''):
         """
@@ -417,7 +457,7 @@ class VppPapiProvider(object):
         :param mac: (Optional)
         """
         return self.api(self.papi.create_loopback,
-                        { 'mac_address' : mac })
+                        {'mac_address': mac})
 
     def ip_add_del_route(
             self,
@@ -428,9 +468,9 @@ class VppPapiProvider(object):
             table_id=0,
             next_hop_table_id=0,
             next_hop_weight=1,
-            next_hop_n_out_labels = 0,
-            next_hop_out_label_stack = [],
-            next_hop_via_label = MPLS_LABEL_INVALID,
+            next_hop_n_out_labels=0,
+            next_hop_out_label_stack=[],
+            next_hop_via_label=MPLS_LABEL_INVALID,
             create_vrf_if_needed=0,
             is_resolve_host=0,
             is_resolve_attached=0,
@@ -470,29 +510,29 @@ class VppPapiProvider(object):
 
         return self.api(
             self.papi.ip_add_del_route,
-            { 'next_hop_sw_if_index' : next_hop_sw_if_index,
-              'table_id' : table_id,
-              'classify_table_index' : classify_table_index,
-              'next_hop_table_id' : next_hop_table_id,
-              'create_vrf_if_needed' : create_vrf_if_needed,
-              'is_add' : is_add,
-              'is_drop' : is_drop,
-              'is_unreach' : is_unreach,
-              'is_prohibit' : is_prohibit,
-              'is_ipv6' : is_ipv6,
-              'is_local' : is_local,
-              'is_classify' : is_classify,
-              'is_multipath' : is_multipath,
-              'is_resolve_host' : is_resolve_host,
-              'is_resolve_attached' : is_resolve_attached,
-              'not_last' : not_last,
-              'next_hop_weight' : next_hop_weight,
-              'dst_address_length' : dst_address_length,
-              'dst_address' : dst_address,
-              'next_hop_address' : next_hop_address,
-              'next_hop_n_out_labels' : next_hop_n_out_labels,
-              'next_hop_via_label' : next_hop_via_label,
-              'next_hop_out_label_stack' : next_hop_out_label_stack })
+            {'next_hop_sw_if_index': next_hop_sw_if_index,
+             'table_id': table_id,
+             'classify_table_index': classify_table_index,
+             'next_hop_table_id': next_hop_table_id,
+             'create_vrf_if_needed': create_vrf_if_needed,
+             'is_add': is_add,
+             'is_drop': is_drop,
+             'is_unreach': is_unreach,
+             'is_prohibit': is_prohibit,
+             'is_ipv6': is_ipv6,
+             'is_local': is_local,
+             'is_classify': is_classify,
+             'is_multipath': is_multipath,
+             'is_resolve_host': is_resolve_host,
+             'is_resolve_attached': is_resolve_attached,
+             'not_last': not_last,
+             'next_hop_weight': next_hop_weight,
+             'dst_address_length': dst_address_length,
+             'dst_address': dst_address,
+             'next_hop_address': next_hop_address,
+             'next_hop_n_out_labels': next_hop_n_out_labels,
+             'next_hop_via_label': next_hop_via_label,
+             'next_hop_out_label_stack': next_hop_out_label_stack})
 
     def ip_neighbor_add_del(self,
                             sw_if_index,
@@ -516,13 +556,13 @@ class VppPapiProvider(object):
 
         return self.api(
             self.papi.ip_neighbor_add_del,
-            { 'vrf_id' : vrf_id,
-              'sw_if_index' : sw_if_index,
-              'is_add' : is_add,
-              'is_ipv6' : is_ipv6,
-              'is_static' : is_static,
-              'mac_address' : mac_address,
-              'dst_address' : dst_address
+            {'vrf_id': vrf_id,
+             'sw_if_index': sw_if_index,
+             'is_add': is_add,
+             'is_ipv6': is_ipv6,
+             'is_static': is_static,
+             'mac_address': mac_address,
+             'dst_address': dst_address
              }
         )
 
@@ -536,9 +576,9 @@ class VppPapiProvider(object):
 
         """
         return self.api(self.papi.sw_interface_span_enable_disable,
-                        { 'sw_if_index_from' : sw_if_index_from,
-                          'sw_if_index_to' : sw_if_index_to,
-                          'state' : state })
+                        {'sw_if_index_from': sw_if_index_from,
+                         'sw_if_index_to': sw_if_index_to,
+                         'state': state})
 
     def gre_tunnel_add_del(self,
                            src_address,
@@ -559,12 +599,12 @@ class VppPapiProvider(object):
 
         return self.api(
             self.papi.gre_add_del_tunnel,
-            { 'is_add' : is_add,
-              'is_ipv6' : is_ip6,
-              'teb' : is_teb,
-              'src_address' : src_address,
-              'dst_address' : dst_address,
-              'outer_fib_id' : outer_fib_id }
+            {'is_add': is_add,
+             'is_ipv6': is_ip6,
+             'teb': is_teb,
+             'src_address': src_address,
+             'dst_address': dst_address,
+             'outer_fib_id': outer_fib_id}
         )
 
     def mpls_route_add_del(
@@ -577,9 +617,9 @@ class VppPapiProvider(object):
             table_id=0,
             next_hop_table_id=0,
             next_hop_weight=1,
-            next_hop_n_out_labels = 0,
-            next_hop_out_label_stack = [],
-            next_hop_via_label = MPLS_LABEL_INVALID,
+            next_hop_n_out_labels=0,
+            next_hop_out_label_stack=[],
+            next_hop_via_label=MPLS_LABEL_INVALID,
             create_vrf_if_needed=0,
             is_resolve_host=0,
             is_resolve_attached=0,
@@ -615,24 +655,24 @@ class VppPapiProvider(object):
 
         return self.api(
             self.papi.mpls_route_add_del,
-            { 'mr_label' : label,
-              'mr_eos' : eos,
-              'mr_table_id' : table_id,
-              'mr_classify_table_index' : classify_table_index,
-              'mr_create_table_if_needed' : create_vrf_if_needed,
-              'mr_is_add' : is_add,
-              'mr_is_classify' : is_classify,
-              'mr_is_multipath' : is_multipath,
-              'mr_is_resolve_host' : is_resolve_host,
-              'mr_is_resolve_attached' : is_resolve_attached,
-              'mr_next_hop_proto_is_ip4' : next_hop_proto_is_ip4,
-              'mr_next_hop_weight' : next_hop_weight,
-              'mr_next_hop' : next_hop_address,
-              'mr_next_hop_n_out_labels' : next_hop_n_out_labels,
-              'mr_next_hop_sw_if_index' : next_hop_sw_if_index,
-              'mr_next_hop_table_id' : next_hop_table_id,
-              'mr_next_hop_via_label' : next_hop_via_label,
-              'mr_next_hop_out_label_stack' : next_hop_out_label_stack })
+            {'mr_label': label,
+             'mr_eos': eos,
+             'mr_table_id': table_id,
+             'mr_classify_table_index': classify_table_index,
+             'mr_create_table_if_needed': create_vrf_if_needed,
+             'mr_is_add': is_add,
+             'mr_is_classify': is_classify,
+             'mr_is_multipath': is_multipath,
+             'mr_is_resolve_host': is_resolve_host,
+             'mr_is_resolve_attached': is_resolve_attached,
+             'mr_next_hop_proto_is_ip4': next_hop_proto_is_ip4,
+             'mr_next_hop_weight': next_hop_weight,
+             'mr_next_hop': next_hop_address,
+             'mr_next_hop_n_out_labels': next_hop_n_out_labels,
+             'mr_next_hop_sw_if_index': next_hop_sw_if_index,
+             'mr_next_hop_table_id': next_hop_table_id,
+             'mr_next_hop_via_label': next_hop_via_label,
+             'mr_next_hop_out_label_stack': next_hop_out_label_stack})
 
     def mpls_ip_bind_unbind(
             self,
@@ -648,14 +688,14 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.mpls_ip_bind_unbind,
-            {'mb_mpls_table_id' : table_id,
-             'mb_label' : label,
-             'mb_ip_table_id' : ip_table_id,
-             'mb_create_table_if_needed' : create_vrf_if_needed,
-             'mb_is_bind' : is_bind,
-             'mb_is_ip4' : is_ip4,
-             'mb_address_length' : dst_address_length,
-             'mb_address' : dst_address})
+            {'mb_mpls_table_id': table_id,
+             'mb_label': label,
+             'mb_ip_table_id': ip_table_id,
+             'mb_create_table_if_needed': create_vrf_if_needed,
+             'mb_is_bind': is_bind,
+             'mb_is_ip4': is_ip4,
+             'mb_address_length': dst_address_length,
+             'mb_address': dst_address})
 
     def mpls_tunnel_add_del(
             self,
@@ -665,9 +705,9 @@ class VppPapiProvider(object):
             next_hop_sw_if_index=0xFFFFFFFF,
             next_hop_table_id=0,
             next_hop_weight=1,
-            next_hop_n_out_labels = 0,
-            next_hop_out_label_stack = [],
-            next_hop_via_label = MPLS_LABEL_INVALID,
+            next_hop_n_out_labels=0,
+            next_hop_out_label_stack=[],
+            next_hop_via_label=MPLS_LABEL_INVALID,
             create_vrf_if_needed=0,
             is_add=1,
             l2_only=0):
@@ -696,19 +736,16 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.mpls_tunnel_add_del,
-            {'mt_sw_if_index' : tun_sw_if_index,
-              'mt_is_add' : is_add,
-              'mt_l2_only' : l2_only,
-              'mt_next_hop_proto_is_ip4' : next_hop_proto_is_ip4,
-              'mt_next_hop_weight' : next_hop_weight,
-              'mt_next_hop' : next_hop_address,
-              'mt_next_hop_n_out_labels' : next_hop_n_out_labels,
-              'mt_next_hop_sw_if_index' :next_hop_sw_if_index,
-              'mt_next_hop_table_id' : next_hop_table_id,
-              'mt_next_hop_out_label_stack' : next_hop_out_label_stack })
-
-        return self.api(vpp_papi.sw_interface_span_enable_disable,
-                        (sw_if_index_from, sw_if_index_to, enable))
+            {'mt_sw_if_index': tun_sw_if_index,
+             'mt_is_add': is_add,
+             'mt_l2_only': l2_only,
+             'mt_next_hop_proto_is_ip4': next_hop_proto_is_ip4,
+             'mt_next_hop_weight': next_hop_weight,
+             'mt_next_hop': next_hop_address,
+             'mt_next_hop_n_out_labels': next_hop_n_out_labels,
+             'mt_next_hop_sw_if_index': next_hop_sw_if_index,
+             'mt_next_hop_table_id': next_hop_table_id,
+             'mt_next_hop_out_label_stack': next_hop_out_label_stack})
 
     def snat_interface_add_del_feature(
             self,
@@ -723,9 +760,9 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.snat_interface_add_del_feature,
-            {'is_add' : is_add,
-             'is_inside' : is_inside,
-             'sw_if_index' : sw_if_index})
+            {'is_add': is_add,
+             'is_inside': is_inside,
+             'sw_if_index': sw_if_index})
 
     def snat_add_static_mapping(
             self,
@@ -750,14 +787,14 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.snat_add_static_mapping,
-            {'is_add' : is_add,
-             'is_ip4' : is_ip4,
-             'addr_only' : addr_only,
-             'local_ip_address' : local_ip,
-             'external_ip_address' : external_ip,
-             'local_port' : local_port,
-             'external_port' : external_port,
-             'vrf_id' : vrf_id})
+            {'is_add': is_add,
+             'is_ip4': is_ip4,
+             'addr_only': addr_only,
+             'local_ip_address': local_ip,
+             'external_ip_address': external_ip,
+             'local_port': local_port,
+             'external_port': external_port,
+             'vrf_id': vrf_id})
 
     def snat_add_address_range(
             self,
@@ -774,10 +811,10 @@ class VppPapiProvider(object):
         """
         return self.api(
             self.papi.snat_add_address_range,
-            {'is_ip4' : is_ip4,
-             'first_ip_address' : first_ip_address,
-             'last_ip_address' : last_ip_address,
-             'is_add' : is_add})
+            {'is_ip4': is_ip4,
+             'first_ip_address': first_ip_address,
+             'last_ip_address': last_ip_address,
+             'is_add': is_add})
 
     def snat_address_dump(self):
         """Dump S-NAT addresses
@@ -796,3 +833,43 @@ class VppPapiProvider(object):
         :return: Dictionary of S-NAT static mappings
         """
         return self.api(self.papi.snat_static_mapping_dump, {})
+
+    def control_ping(self):
+        self.api(self.papi.control_ping)
+
+    def bfd_udp_add(self, sw_if_index, desired_min_tx, required_min_rx,
+                    detect_mult, local_addr, peer_addr, is_ipv6=0):
+        return self.api(self.papi.bfd_udp_add,
+                        {
+                            'sw_if_index': sw_if_index,
+                            'desired_min_tx': desired_min_tx,
+                            'required_min_rx': required_min_rx,
+                            'local_addr': local_addr,
+                            'peer_addr': peer_addr,
+                            'is_ipv6': is_ipv6,
+                            'detect_mult': detect_mult,
+                        })
+
+    def bfd_udp_del(self, sw_if_index, local_addr, peer_addr, is_ipv6=0):
+        return self.api(self.papi.bfd_udp_del,
+                        {
+                            'sw_if_index': sw_if_index,
+                            'local_addr': local_addr,
+                            'peer_addr': peer_addr,
+                            'is_ipv6': is_ipv6,
+                        })
+
+    def bfd_udp_session_dump(self):
+        return self.api(self.papi.bfd_udp_session_dump, {})
+
+    def bfd_session_set_flags(self, bs_idx, admin_up_down):
+        return self.api(self.papi.bfd_session_set_flags, {
+            'bs_index': bs_idx,
+            'admin_up_down': admin_up_down,
+        })
+
+    def want_bfd_events(self, enable_disable=1):
+        return self.api(self.papi.want_bfd_events, {
+            'enable_disable': enable_disable,
+            'pid': os.getpid(),
+        })
diff --git a/test/vpp_pg_interface.py b/test/vpp_pg_interface.py
index 533c4603a2e..012f5768353 100644
--- a/test/vpp_pg_interface.py
+++ b/test/vpp_pg_interface.py
@@ -1,10 +1,10 @@
 import os
 import time
-from scapy.utils import wrpcap, rdpcap
+from scapy.utils import wrpcap, rdpcap, PcapReader
 from vpp_interface import VppInterface
 
 from scapy.layers.l2 import Ether, ARP
-from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA, \
+from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr
 from util import ppp
 
@@ -93,6 +93,7 @@ class VppPGInterface(VppInterface):
             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):
         """
@@ -132,6 +133,41 @@ class VppPGInterface(VppInterface):
             return []
         return output
 
+    def wait_for_packet(self, timeout):
+        """
+        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
+        """
+        limit = time.time() + timeout
+        if self._pcap_reader is None:
+            self.test.logger.debug("Waiting for the capture file to appear")
+            while time.time() < limit:
+                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() - (limit - timeout)))
+                self._pcap_reader = PcapReader(self.out_path)
+            else:
+                self.test.logger.debug("Timeout - capture file still nowhere")
+                raise Exception("Packet didn't arrive within timeout")
+
+        self.test.logger.debug("Waiting for packet")
+        while time.time() < limit:
+            p = self._pcap_reader.recv()
+            if p is not None:
+                self.test.logger.debug("Packet received after %fs",
+                                       (time.time() - (limit - timeout)))
+                return p
+            time.sleep(0)  # yield
+        self.test.logger.debug("Timeout - no packets received")
+        raise Exception("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) /