Ignore unexpected ICMPv6 Neighbor Discovery - Neighbor Solicitation packets

We need to adapt all functional traffic scripts related to functional
IPv6 tests to ingore receiving of unexpected ICMPv6ND_NS
(ICMPv6 Neighbor Discovery - Neighbor Solicitation) packets that are
sent automatically and we cannot avoid to receive them.

The reason is to prevent false negative test results in case of csit
functional tests that could block creation of new operational branch
(csit weekly jobs), usage of new vpp builds (csit semiweekly jobs)
and merging patches - csit as well as vpp.

Change-Id: I43c90e7c766762fa769a81661338759a11b401a1
Signed-off-by: Jan Gelety <jgelety@cisco.com>

1 files changed, 33 insertions, 24 deletions

diff --git a/resources/traffic_scripts/send_ip_icmp.py b/resources/traffic_scripts/send_ip_icmp.py
index b22b5d39a8..58f2e1e4d8 100755
--- a/resources/traffic_scripts/send_ip_icmp.py
+++ b/resources/traffic_scripts/send_ip_icmp.py
@@ -19,11 +19,9 @@ the other one. Dot1q or Dot1ad tagging of the ethernet frame can be set.
 import sys
 import ipaddress
 
+from scapy.layers.l2 import Ether,  Dot1Q
 from scapy.layers.inet import ICMP, IP
-from scapy.layers.l2 import Ether
-from scapy.layers.l2 import Dot1Q
-from scapy.layers.inet6 import ICMPv6EchoRequest
-from scapy.layers.inet6 import IPv6
+from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6ND_NS
 
 from resources.libraries.python.PacketVerifier import RxQueue, TxQueue
 from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
@@ -107,8 +105,8 @@ def main():
             pkt_raw = (Ether(src=src_mac, dst=dst_mac) /
                        IP(src=src_ip, dst=dst_ip) /
                        ICMP())
-        ip_format = 'IP'
-        icmp_format = 'ICMP'
+        ip_format = IP
+        icmp_format = ICMP
     elif valid_ipv6(src_ip) and valid_ipv6(dst_ip):
         if encaps == 'Dot1q':
             pkt_raw = (Ether(src=src_mac, dst=dst_mac) /
@@ -125,8 +123,8 @@ def main():
             pkt_raw = (Ether(src=src_mac, dst=dst_mac) /
                        IPv6(src=src_ip, dst=dst_ip) /
                        ICMPv6EchoRequest())
-        ip_format = 'IPv6'
-        icmp_format = 'ICMPv6EchoRequest'
+        ip_format = IPv6
+        icmp_format = ICMPv6EchoRequest
     else:
         raise ValueError("IP(s) not in correct format")
 
@@ -134,44 +132,55 @@ def main():
     sent_packets.append(pkt_raw)
     txq.send(pkt_raw)
 
-    ether = rxq.recv(2)
+    # Receive ICMP / ICMPv6 echo reply
+    while True:
+        ether = rxq.recv(2,)
+        if ether is None:
+            raise RuntimeError('ICMP echo Rx timeout')
 
-    # Check whether received packet contains layers Ether, IP and ICMP
-    if ether is None:
-        raise RuntimeError('ICMP echo Rx timeout')
+        if ether.haslayer(ICMPv6ND_NS):
+            # read another packet in the queue if the current one is ICMPv6ND_NS
+            continue
+        else:
+            # otherwise process the current packet
+            break
 
+    # Check whether received packet contains layers IP/IPv6 and
+    # ICMP/ICMPv6EchoRequest
     if encaps_rx:
         if encaps_rx == 'Dot1q':
             if not vlan1_rx:
                 vlan1_rx = vlan1
             if not ether.haslayer(Dot1Q):
-                raise RuntimeError('Not VLAN tagged Eth frame received:\n{0}'
-                                   .format(ether.__repr__()))
+                raise RuntimeError('Not VLAN tagged Eth frame received:\n{0}'.
+                                   format(ether.__repr__()))
             elif ether[Dot1Q].vlan != int(vlan1_rx):
                 raise RuntimeError('Ethernet frame with wrong VLAN tag ({}) '
-                                   'received ({} expected):\n{}'.format(
-                    ether[Dot1Q].vlan, vlan1_rx, ether.__repr__()))
+                                   'received ({} expected):\n{}'.
+                                   format(ether[Dot1Q].vlan, vlan1_rx,
+                                          ether.__repr__()))
         elif encaps_rx == 'Dot1ad':
             if not vlan1_rx:
                 vlan1_rx = vlan1
             if not vlan2_rx:
                 vlan2_rx = vlan2
             # TODO
-            raise RuntimeError('Encapsulation {0} not implemented yet.'
-                               .format(encaps_rx))
+            raise RuntimeError('Encapsulation {0} not implemented yet.'.
+                               format(encaps_rx))
         else:
-            raise RuntimeError('Unsupported/unknown encapsulation expected: {0}'
-                               .format(encaps_rx))
+            raise RuntimeError('Unsupported encapsulation expected: {0}'.
+                               format(encaps_rx))
 
     if not ether.haslayer(ip_format):
-        raise RuntimeError('Not an IP packet received:\n{0}'
-                           .format(ether.__repr__()))
+        raise RuntimeError('Not an IP/IPv6 packet received:\n{0}'.
+                           format(ether.__repr__()))
 
     if not ether.haslayer(icmp_format):
-        raise RuntimeError('Not an ICMP packet received:\n{0}'
-                           .format(ether.__repr__()))
+        raise RuntimeError('Not an ICMP/ICMPv6EchoRequest packet received:\n'
+                           '{0}'.format(ether.__repr__()))
 
     sys.exit(0)
 
+
 if __name__ == "__main__":
     main()