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, 26 insertions, 19 deletions

diff --git a/resources/traffic_scripts/send_icmp_check_headers.py b/resources/traffic_scripts/send_icmp_check_headers.py
index c9e3a35df4..2193164b61 100755
--- a/resources/traffic_scripts/send_icmp_check_headers.py
+++ b/resources/traffic_scripts/send_icmp_check_headers.py
@@ -22,8 +22,7 @@ import sys
 import ipaddress
 from robot.api import logger
 from scapy.layers.inet import ICMP, IP
-from scapy.layers.inet6 import ICMPv6EchoRequest
-from scapy.layers.inet6 import IPv6
+from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6ND_NS
 from scapy.layers.l2 import Ether, Dot1Q
 
 from resources.libraries.python.PacketVerifier import RxQueue, TxQueue
@@ -94,28 +93,36 @@ def main():
 
     sent_packets.append(pkt_raw)
     txq.send(pkt_raw)
-    if tx_if == rx_if:
-        ether = rxq.recv(2, ignore=sent_packets)
-    else:
-        ether = rxq.recv(2)
 
-    if ether is None:
-        raise RuntimeError("ICMP echo Rx timeout")
+    while True:
+        if tx_if == rx_if:
+            ether = rxq.recv(2, ignore=sent_packets)
+        else:
+            ether = rxq.recv(2)
+        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
 
     if rx_dst_mac == ether[Ether].dst and rx_src_mac == ether[Ether].src:
         logger.trace("MAC matched")
     else:
-        raise RuntimeError(
-            "Matching packet unsuccessful: {0}".format(ether.__repr__()))
+        raise RuntimeError("Matching packet unsuccessful: {0}".
+                           format(ether.__repr__()))
 
     if encaps_rx == 'Dot1q':
         if ether[Dot1Q].vlan == int(vlan_rx):
             logger.trace("VLAN matched")
         else:
             raise RuntimeError('Ethernet frame with wrong VLAN tag ({}-'
-                               'received, {}-expected):\n{}'
-                               .format(ether[Dot1Q].vlan, vlan_rx,
-                                       ether.__repr__()))
+                               'received, {}-expected):\n{}'.
+                               format(ether[Dot1Q].vlan, vlan_rx,
+                                      ether.__repr__()))
         ip = ether[Dot1Q].payload
     elif encaps_rx == 'Dot1ad':
         raise NotImplementedError()
@@ -123,21 +130,21 @@ def main():
         ip = ether.payload
 
     if not isinstance(ip, ip_format):
-        raise RuntimeError(
-            "Not an IP packet received {0}".format(ip.__repr__()))
+        raise RuntimeError("Not an IP packet received {0}".
+                           format(ip.__repr__()))
 
     # Compare data from packets
     if src_ip == ip.src:
         logger.trace("Src IP matched")
     else:
-        raise RuntimeError("Matching Src IP unsuccessful: {} != {}"
-                           .format(src_ip, ip.src))
+        raise RuntimeError("Matching Src IP unsuccessful: {} != {}".
+                           format(src_ip, ip.src))
 
     if dst_ip == ip.dst:
         logger.trace("Dst IP matched")
     else:
-        raise RuntimeError("Matching Dst IP unsuccessful: {} != {}"
-                           .format(dst_ip, ip.dst))
+        raise RuntimeError("Matching Dst IP unsuccessful: {} != {}".
+                           format(dst_ip, ip.dst))
 
     sys.exit(0)