bfd: Send FINAL immediately after receiving POLL.

Commit 307464a11 (ofproto-dpif-monitor: Use heap to order the mport
wakeup time.) makes bfd only send packet at specified periodic instant.
This fails to meet the RFC5880 requirement, which requires bfd send
FINAL immediately after receiving POLL.

This commit fixes the above issue by scheduling bfd to send FINAL
within 100 ms after receiving POLL.

Signed-off-by: Alex Wang <alexw@nicira.com>

3 files changed, 39 insertions, 2 deletions

diff --git a/ofproto/ofproto-dpif-monitor.c b/ofproto/ofproto-dpif-monitor.c
index af66387b7..f67f0363a 100644
--- a/ofproto/ofproto-dpif-monitor.c
+++ b/ofproto/ofproto-dpif-monitor.c
@@ -225,8 +225,9 @@ monitor_run(void)
             bfd_wait(mport->bfd);
         }
         /* Computes the next wakeup time for this mport. */
-        next_wake_time = MIN(bfd_wake_time(mport->bfd), cfm_wake_time(mport->cfm));
-        heap_change(&monitor_heap, heap_max(&monitor_heap),
+        next_wake_time = MIN(bfd_wake_time(mport->bfd),
+                             cfm_wake_time(mport->cfm));
+        heap_change(&monitor_heap, &mport->heap_node,
                     MSEC_TO_PRIO(next_wake_time));
     }
 
@@ -275,3 +276,27 @@ ofproto_dpif_monitor_port_update(const struct ofport_dpif *ofport,
         monitor_running = false;
     }
 }
+
+/* Moves the mport on top of the heap.  This is necessary when
+ * for example, bfd POLL is received and the mport should
+ * immediately send FINAL back. */
+void
+ofproto_dpif_monitor_port_send_soon_safe(const struct ofport_dpif *ofport)
+{
+    ovs_rwlock_wrlock(&monitor_rwlock);
+    ofproto_dpif_monitor_port_send_soon(ofport);
+    ovs_rwlock_unlock(&monitor_rwlock);
+}
+
+void
+ofproto_dpif_monitor_port_send_soon(const struct ofport_dpif *ofport)
+    OVS_REQ_WRLOCK(monitor_rwlock)
+{
+    struct mport *mport;
+
+    monitor_init();
+    mport = mport_find(ofport);
+    if (mport) {
+        heap_change(&monitor_heap, &mport->heap_node, LLONG_MAX);
+    }
+}
diff --git a/ofproto/ofproto-dpif-monitor.h b/ofproto/ofproto-dpif-monitor.h
index f914fbe93..1f6be5cf9 100644
--- a/ofproto/ofproto-dpif-monitor.h
+++ b/ofproto/ofproto-dpif-monitor.h
@@ -23,6 +23,9 @@ struct bfd;
 struct cfm;
 struct ofport_dpif;
 
+void ofproto_dpif_monitor_port_send_soon(const struct ofport_dpif *);
+void ofproto_dpif_monitor_port_send_soon_safe(const struct ofport_dpif *);
+
 void ofproto_dpif_monitor_port_update(const struct ofport_dpif *,
                                       struct bfd *, struct cfm *,
                                       uint8_t[OFP_ETH_ALEN]);
diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index 09406b72a..848c7780b 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -42,6 +42,7 @@
 #include "ofp-actions.h"
 #include "ofproto/ofproto-dpif-ipfix.h"
 #include "ofproto/ofproto-dpif-mirror.h"
+#include "ofproto/ofproto-dpif-monitor.h"
 #include "ofproto/ofproto-dpif-sflow.h"
 #include "ofproto/ofproto-dpif.h"
 #include "ofproto/ofproto-provider.h"
@@ -1645,6 +1646,14 @@ process_special(struct xlate_ctx *ctx, const struct flow *flow,
     } else if (xport->bfd && bfd_should_process_flow(xport->bfd, flow, wc)) {
         if (packet) {
             bfd_process_packet(xport->bfd, flow, packet);
+            /* If POLL received, immediately sends FINAL back. */
+            if (bfd_should_send_packet(xport->bfd)) {
+                if (xport->peer) {
+                    ofproto_dpif_monitor_port_send_soon(xport->ofport);
+                } else {
+                    ofproto_dpif_monitor_port_send_soon_safe(xport->ofport);
+                }
+            }
         }
         return SLOW_BFD;
     } else if (xport->xbundle && xport->xbundle->lacp