cfm: Require ccm received in demand mode.

This commit adds a new requirement that cfm session must receive
at least one ccm every 100 * cfm_interval amount of time in demand
mode.  Otherwise, even if the data packets are received on the
monitored interface, the cfm session still reports "[recv]" fault.

Since the datapath flow is not purged when the userspace Open Vswitch
crashes, data packet can still be forwarded through the tunnel and
fool the remote CFM session in demand mode.  Thus, this commit can
prevent the remote CFM session from falsely declaring tunnel liveness
in this situation.

Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/tests/cfm.at b/tests/cfm.at
index a3c44a158..fdca4ace5 100644
--- a/tests/cfm.at
+++ b/tests/cfm.at
@@ -14,6 +14,19 @@ Remote MPID $7
 ])
 ])
 
+m4_define([CFM_CHECK_EXTENDED_FAULT], [
+AT_CHECK([ovs-appctl cfm/show $1 | sed -e '/next CCM tx:/d' | sed -e '/next fault check:/d' | sed -e  '/recv since check:/d'],[0],
+[dnl
+---- $1 ----
+MPID $2: extended
+	fault: $3
+	average health: $4
+	opstate: $5
+	remote_opstate: $6
+	interval: $7
+])
+])
+
 m4_define([CFM_VSCTL_LIST_IFACE], [
 AT_CHECK([ovs-vsctl list interface $1 | sed -n '/$2/p'],[0],
 [dnl
@@ -101,6 +114,68 @@ done
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+# test demand_rx_ccm under demand mode.
+AT_SETUP([cfm - demand_rx_ccm])
+#Create 2 bridges connected by patch ports and enable cfm
+OVS_VSWITCHD_START([add-br br1 -- \
+                    set bridge br1 datapath-type=dummy \
+                    other-config:hwaddr=aa:55:aa:56:00:00 -- \
+                    add-port br1 p1 -- set Interface p1 type=patch \
+                    options:peer=p0 ofport_request=2 -- \
+                    add-port br0 p0 -- set Interface p0 type=patch \
+                    options:peer=p1 ofport_request=1 -- \
+                    set Interface p0 cfm_mpid=1 other_config:cfm_interval=300 other_config:cfm_extended=true other_config:cfm_demand=true -- \
+                    set Interface p1 cfm_mpid=2 other_config:cfm_interval=300 other_config:cfm_extended=true other_config:cfm_demand=true])
+
+ovs-appctl time/stop
+# wait for a while to stablize cfm. (need a longer time, since in demand mode
+# the fault interval is (MAX(ccm_interval_ms, 500) * 3.5) ms)
+for i in `seq 0 200`; do ovs-appctl time/warp 100; done
+CFM_CHECK_EXTENDED([p0], [1], [100], [up], [up], [300ms], [2], [up])
+CFM_CHECK_EXTENDED([p1], [2], [100], [up], [up], [300ms], [1], [up])
+
+# turn off the cfm on p1.
+AT_CHECK([ovs-vsctl clear Interface p1 cfm_mpid])
+# cfm should never go down while receiving data packets.
+for i in `seq 0 200`
+do
+    ovs-appctl time/warp 100
+    AT_CHECK([ovs-ofctl packet-out br1 3 2  "90e2ba01475000101856b2e80806000108000604000100101856b2e80202020300000000000002020202"],
+             [0], [stdout], [])
+done
+CFM_CHECK_EXTENDED([p0], [1], [0], [up], [up], [300ms], [2], [up])
+
+# wait longer, since the demand_rx_ccm interval is 100 * 300 ms.
+# since there is no ccm received, the [recv] fault should be raised.
+for i in `seq 0 200`
+do
+    ovs-appctl time/warp 100
+    AT_CHECK([ovs-ofctl packet-out br1 3 2  "90e2ba01475000101856b2e80806000108000604000100101856b2e80202020300000000000002020202"],
+             [0], [stdout], [])
+done
+CFM_CHECK_EXTENDED_FAULT([p0], [1], [recv], [0], [up], [up], [300ms])
+
+# now turn on the cfm on p1 again,
+AT_CHECK([ovs-vsctl set Interface p1 cfm_mpid=2])
+# cfm should be up for both p0 and p1
+for i in `seq 0 200`; do ovs-appctl time/warp 100; done
+CFM_CHECK_EXTENDED([p0], [1], [100], [up], [up], [300ms], [2], [up])
+CFM_CHECK_EXTENDED([p1], [2], [100], [up], [up], [300ms], [1], [up])
+
+# now turn off the cfm on p1 again
+AT_CHECK([ovs-vsctl clear Interface p1 cfm_mpid])
+# since there is no ccm received, the [recv] fault should be raised.
+for i in `seq 0 400`
+do
+    ovs-appctl time/warp 100
+    AT_CHECK([ovs-ofctl packet-out br1 3 2  "90e2ba01475000101856b2e80806000108000604000100101856b2e80202020300000000000002020202"],
+             [0], [stdout], [])
+done
+CFM_CHECK_EXTENDED_FAULT([p0], [1], [recv], [0], [up], [up], [300ms])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
 # test cfm_flap_count.
 AT_SETUP([cfm - flap_count])
 #Create 2 bridges connected by patch ports and enable cfm