Fix quagga peering by working around the NAT

Quagga peering doesn't seem to work over the NATted openstack external
network. To work around this, directly patch the quagga instance to the
external network and give it a fixed IP in that network. Then, all the
peering traffic goes over that patched interface.

Change-Id: I8d9d8fef4e86839c821f83e564d5c49cc15e43ae
JIRA: SDNVPN-114
Signed-off-by: Romanos Skiadas <rski@intracom-telecom.com>
(cherry picked from commit 1ad4cd4d35bcd0d4d9898650eb0452b184b55f77)

3 files changed, 44 insertions, 6 deletions

diff --git a/sdnvpn/artifacts/quagga_setup.sh b/sdnvpn/artifacts/quagga_setup.sh
index 6da50e1..0b810a8 100644
--- a/sdnvpn/artifacts/quagga_setup.sh
+++ b/sdnvpn/artifacts/quagga_setup.sh
@@ -12,6 +12,11 @@ sleep 20
 # Variables to be filled in with python
 NEIGHBOR_IP=%s
 OWN_IP=%s
+# directly access the instance from the external net without NAT
+EXT_NET_MASK=%s
+
+ip link set ens7 up
+ip addr add $OWN_IP/$EXT_NET_MASK dev ens7
 
 ZEBRA_CONFIG_LOCATION="/etc/quagga/zebra.conf"
 DAEMONS_FILE_LOCATION="/etc/quagga/daemons"
diff --git a/sdnvpn/lib/quagga.py b/sdnvpn/lib/quagga.py
index e2885c2..9f8a4cd 100644
--- a/sdnvpn/lib/quagga.py
+++ b/sdnvpn/lib/quagga.py
@@ -29,10 +29,14 @@ def bootstrap_quagga(fip_addr, controller_ip):
     return rc == 0
 
 
-def gen_quagga_setup_script(controller_ip, instance_floating_ip):
+def gen_quagga_setup_script(controller_ip,
+                            fake_floating_ip,
+                            ext_net_mask):
     with open(COMMON_CONFIG.quagga_setup_script_path) as f:
         template = f.read()
-    script = template % (controller_ip, instance_floating_ip)
+    script = template % (controller_ip,
+                         fake_floating_ip,
+                         ext_net_mask)
     return script
 
 
diff --git a/sdnvpn/test/functest/testcase_3.py b/sdnvpn/test/functest/testcase_3.py
index 8bbc738..2bccb57 100644
--- a/sdnvpn/test/functest/testcase_3.py
+++ b/sdnvpn/test/functest/testcase_3.py
@@ -59,6 +59,7 @@ def main():
 
     controllers = [node for node in openstack_nodes
                    if node.is_odl()]
+    computes = [node for node in openstack_nodes if node.is_compute()]
     msg = ("Verify that OpenDaylight can start/communicate with zrpcd/Quagga")
     results.record_action(msg)
     results.add_to_summary(0, "-")
@@ -91,7 +92,6 @@ def main():
 
         results.add_to_summary(0, "-")
 
-        # TODO here we need the external ip of the controller
         start_quagga = "odl:configure-bgp -op start-bgp-server " \
                        "--as-num 100 --router-id {0}".format(controller.ip)
         test_utils.run_odl_cmd(controller, start_quagga)
@@ -187,9 +187,27 @@ def main():
     # We also create the FIP first because it is used in the
     # cloud-init script.
     fip = os_utils.create_floating_ip(neutron_client)
-
+    # fake_fip is needed to bypass NAT
+    # see below for the reason why.
+    fake_fip = os_utils.create_floating_ip(neutron_client)
+    # pin quagga to some compute
+    compute_node = nova_client.hypervisors.list()[0]
+    quagga_compute_node = "nova:" + compute_node.hypervisor_hostname
+    # Map the hypervisor used above to a compute handle
+    # returned by releng's manager
+    for comp in computes:
+        if compute_node.host_ip in comp.run_cmd("ip a"):
+            compute = comp
+            break
+    # Get the mask of ext net of the compute where quagga is running
+    # TODO check this works on apex
+    cmd = "ip a | grep br-ex | grep inet | awk '{print $2}'"
+    ext_cidr = compute.run_cmd(cmd).split("/")
+    ext_net_mask = ext_cidr[1]
     quagga_bootstrap_script = quagga.gen_quagga_setup_script(
-        controllers[0].ip, fip['fip_addr'])
+        controllers[0].ip,
+        fake_fip['fip_addr'],
+        ext_net_mask)
     quagga_vm = test_utils.create_instance(
         nova_client,
         TESTCASE_CONFIG.quagga_instance_name,
@@ -198,7 +216,9 @@ def main():
         sg_id,
         fixed_ip=TESTCASE_CONFIG.quagga_instance_ip,
         flavor=TESTCASE_CONFIG.quagga_instance_flavor,
-        userdata=quagga_bootstrap_script)
+        userdata=quagga_bootstrap_script,
+        compute_node=quagga_compute_node)
+
     fip_added = os_utils.add_floating_ip(nova_client,
                                          quagga_vm.id,
                                          fip['fip_addr'])
@@ -217,6 +237,15 @@ def main():
         results.add_failure(testcase)
     results.add_to_summary(0, "=")
 
+    # This part works around NAT
+    # What we do is attach the instance directly to the OpenStack
+    # external network. This way is is directly accessible from the
+    # controller without NAT. We assign a floating IP for this
+    # to make sure no overlaps happen.
+    libvirt_instance_name = getattr(quagga_vm, "OS-EXT-SRV-ATTR:instance_name")
+    compute.run_cmd("virsh attach-interface %s"
+                    " bridge br-ex" % libvirt_instance_name)
+
     results.add_to_summary(0, '-')
     results.add_to_summary(1, "Peer Quagga with OpenDaylight")
     results.add_to_summary(0, '-')