mac-learning: Fix learned fdb entries not age out issue.

After user add a static fdb entry, the get_lru() function will always
return the static fdb entry.  That's normal fdb entries will not age
out through mac_learning_run().

Fix the issue by modify the get_lru() function to check the
entry->expires field and not return the entry which entry->expires is
MAC_ENTRY_AGE_STATIC_ENTRY.

Adding a unit test for this.

Fixes: ccc24fc88d59 ("ofproto-dpif: APIs and CLI option to add/delete static fdb entry.")
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Tested-by: Zhang Yuhuang <zhangyuhuang@ruijie.com.cn>
Signed-off-by: Lin Huang <linhuang@ruijie.com.cn>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

2 files changed, 37 insertions, 23 deletions

diff --git a/lib/mac-learning.c b/lib/mac-learning.c
index a60794fb2..5932e2709 100644
--- a/lib/mac-learning.c
+++ b/lib/mac-learning.c
@@ -176,12 +176,18 @@ get_lru(struct mac_learning *ml, struct mac_entry **e)
     OVS_REQ_RDLOCK(ml->rwlock)
 {
     if (!ovs_list_is_empty(&ml->lrus)) {
-        *e = mac_entry_from_lru_node(ml->lrus.next);
-        return true;
-    } else {
-        *e = NULL;
-        return false;
+        struct mac_entry *entry;
+
+        LIST_FOR_EACH (entry, lru_node, &ml->lrus) {
+            if (entry->expires != MAC_ENTRY_AGE_STATIC_ENTRY) {
+                *e = entry;
+                return true;
+            }
+        }
     }
+
+    *e = NULL;
+    return false;
 }
 
 static unsigned int
@@ -618,25 +624,10 @@ mac_learning_expire(struct mac_learning *ml, struct mac_entry *e)
 void
 mac_learning_flush(struct mac_learning *ml)
 {
-    struct mac_entry *e, *first_static_mac = NULL;
-
-    while (get_lru(ml, &e) && (e != first_static_mac)) {
-
-        /* Static mac should not be evicted. */
-        if (MAC_ENTRY_AGE_STATIC_ENTRY == e->expires) {
-
-            /* Make note of first static-mac encountered, so that this while
-             * loop will break on visting this mac again via get_lru(). */
-            if (!first_static_mac) {
-                first_static_mac = e;
-            }
+    struct mac_entry *e;
 
-            /* Remove from lru head and append it to tail. */
-            ovs_list_remove(&e->lru_node);
-            ovs_list_push_back(&ml->lrus, &e->lru_node);
-        } else {
-            mac_learning_expire(ml, e);
-        }
+    while (get_lru(ml, &e)) {
+        mac_learning_expire(ml, e);
     }
     hmap_shrink(&ml->table);
 }
diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
index 1a8de7398..73a5e8c3d 100644
--- a/tests/ofproto-dpif.at
+++ b/tests/ofproto-dpif.at
@@ -7146,6 +7146,29 @@ AT_CHECK([ovs-appctl coverage/read-counter mac_learning_static_none_move], [0],
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([ofproto-dpif - static-mac learned mac age out])
+OVS_VSWITCHD_START([set bridge br0 fail-mode=standalone -- set bridge br0 other_config:mac-aging-time=5])
+add_of_ports br0 1 2
+
+dnl Add some static mac entries.
+AT_CHECK([ovs-appctl fdb/add br0 p1 0 50:54:00:00:01:01])
+AT_CHECK([ovs-appctl fdb/add br0 p2 0 50:54:00:00:02:02])
+
+dnl Generate some dynamic fdb entries on some ports.
+OFPROTO_TRACE([ovs-dummy], [in_port(1),eth(src=60:54:00:00:00:01)], [-generate], [100,2])
+OFPROTO_TRACE([ovs-dummy], [in_port(2),eth(src=60:54:00:00:00:02)], [-generate], [100,1])
+
+dnl Waiting for aging out.
+ovs-appctl time/warp 20000
+
+dnl Count number of static entries remaining.
+AT_CHECK_UNQUOTED([ovs-appctl fdb/stats-show br0 | grep expired], [0], [dnl
+  Total number of expired MAC entries     : 2
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_SETUP([ofproto-dpif - basic truncate action])
 OVS_VSWITCHD_START
 add_of_ports br0 1 2 3 4 5