When waiting for an IPv6 response, filter non-ND packets

[vpp.git] / test / vpp_pg_interface.py

diff --git a/test/vpp_pg_interface.py b/test/vpp_pg_interface.py
index 533c460..2ebcbb5 100644 (file)
--- 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) /
@@ -202,24 +238,29 @@ class VppPGInterface(VppInterface):
         pg_interface.enable_capture()
         self.test.pg_start()
         self.test.logger.info(self.test.vapi.cli("show trace"))
-        ndp_reply = pg_interface.get_capture()
-        if ndp_reply is None or len(ndp_reply) == 0:
+        replies = pg_interface.get_capture()
+        if replies is None or len(replies) == 0:
             self.test.logger.info(
                 "No NDP received on port %s" %
                 pg_interface.name)
             return
-        ndp_reply = ndp_reply[0]
-        # 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
-        except:
-            self.test.logger.error(
-                ppp("Unexpected response to NDP request:", ndp_reply))
+        # 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.
+        for ndp_reply in replies:
+            # 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
+            except:
+                self.test.logger.info(
+                    ppp("Unexpected response to NDP request:", ndp_reply))
+        # if no packets above provided the local MAC, then this failed.
+        if not hasattr(self, '_local_mac'):
             raise