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, 20 insertions, 17 deletions

diff --git a/resources/traffic_scripts/send_tcp_for_classifier_test.py b/resources/traffic_scripts/send_tcp_for_classifier_test.py
index 5d8d387767..5a6873ab4e 100755
--- a/resources/traffic_scripts/send_tcp_for_classifier_test.py
+++ b/resources/traffic_scripts/send_tcp_for_classifier_test.py
@@ -17,27 +17,24 @@ Traffic script that sends an TCP packet
 from TG to DUT.
 """
 import sys
-import time
 
-from scapy.layers.inet import IP, UDP, TCP
-from scapy.layers.inet6 import IPv6
 from scapy.all import Ether, Packet, Raw
+from scapy.layers.inet import IP, TCP
+from scapy.layers.inet6 import IPv6, ICMPv6ND_NS
 
 from resources.libraries.python.SFC.VerifyPacket import *
-from resources.libraries.python.SFC.SFCConstants import SFCConstants as sfccon
+from resources.libraries.python.SFC.SFCConstants import SFCConstants as SfcCon
 from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
 from resources.libraries.python.PacketVerifier import RxQueue, TxQueue
 
-from robot.api import logger
 
 def main():
     """Send TCP packet from one traffic generator interface to DUT.
 
     :raises: If the IP address is invalid.
     """
-    args = TrafficScriptArg(
-        ['src_mac', 'dst_mac', 'src_ip', 'dst_ip',
-        'timeout', 'framesize', 'testtype'])
+    args = TrafficScriptArg(['src_mac', 'dst_mac', 'src_ip', 'dst_ip',
+                             'timeout', 'framesize', 'testtype'])
 
     src_mac = args.get_arg('src_mac')
     dst_mac = args.get_arg('dst_mac')
@@ -54,10 +51,9 @@ def main():
     sent_packets = []
 
     protocol = TCP
-    source_port = sfccon.DEF_SRC_PORT
-    destination_port = sfccon.DEF_DST_PORT
+    source_port = SfcCon.DEF_SRC_PORT
+    destination_port = SfcCon.DEF_DST_PORT
 
-    ip_version = None
     if valid_ipv4(src_ip) and valid_ipv4(dst_ip):
         ip_version = IP
     elif valid_ipv6(src_ip) and valid_ipv6(dst_ip):
@@ -66,8 +62,8 @@ def main():
         raise ValueError("Invalid IP version!")
 
     pkt_header = (Ether(src=src_mac, dst=dst_mac) /
-               ip_version(src=src_ip, dst=dst_ip) /
-               protocol(sport=int(source_port), dport=int(destination_port)))
+                  ip_version(src=src_ip, dst=dst_ip) /
+                  protocol(sport=int(source_port), dport=int(destination_port)))
 
     fsize_no_fcs = frame_size - 4
     pad_len = max(0, fsize_no_fcs - len(pkt_header))
@@ -79,10 +75,17 @@ def main():
     sent_packets.append(pkt_raw)
     txq.send(pkt_raw)
 
-    ether = rxq.recv(timeout)
-
-    if ether is None:
-        raise RuntimeError("No packet is received!")
+    while True:
+        ether = rxq.recv(timeout)
+        if ether is None:
+            raise RuntimeError('No packet is received!')
+
+        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
 
     # let us begin to check the NSH SFC loopback  packet
     VerifyPacket.check_the_nsh_sfc_packet(ether, frame_size, test_type)