conntrack: simplify cleanup path

The conntrack cleanup and allocation code is spread across multiple
list invocations.  This was changed in mainline code when the timeout
expiration lists were refactored, but backporting those fixes would
be a rather large effort.  Instead, take only the changes we need
to backport "contrack: Remove nat_conn introducing key directionality"
into branch-2.17.

Signed-off-by: Aaron Conole <[email protected]>
Co-authored-by: Paolo Valerio <[email protected]>
Signed-off-by: Paolo Valerio <[email protected]>
Signed-off-by: 0-day Robot <[email protected]>

lib/conntrack.c

@@ -94,9 +94,8 @@ static bool valid_new(struct dp_packet *pkt, struct conn_key *);
 static struct conn *new_conn(struct conntrack *ct, struct dp_packet *pkt,
                              struct conn_key *, long long now,
                              uint32_t tp_id);
-static void delete_conn_cmn(struct conn *);
+static void delete_conn__(struct conn *);
 static void delete_conn(struct conn *);
-static void delete_conn_one(struct conn *conn);
 static enum ct_update_res conn_update(struct conntrack *ct, struct conn *conn,
                                       struct dp_packet *pkt,
                                       struct conn_lookup_ctx *ctx,
@@ -444,9 +443,11 @@ zone_limit_delete(struct conntrack *ct, uint16_t zone)
 }
 
 static void
-conn_clean_cmn(struct conntrack *ct, struct conn *conn)
+conn_clean(struct conntrack *ct, struct conn *conn)
     OVS_REQUIRES(ct->ct_lock)
 {
+    ovs_assert(conn->conn_type == CT_CONN_TYPE_DEFAULT);
+
     if (conn->alg) {
         expectation_clean(ct, &conn->key);
     }
@@ -458,19 +459,9 @@ conn_clean_cmn(struct conntrack *ct, struct conn *conn)
     if (zl && zl->czl.zone_limit_seq == conn->zone_limit_seq) {
         zl->czl.count--;
     }
-}
 
-/* Must be called with 'conn' of 'conn_type' CT_CONN_TYPE_DEFAULT.  Also
- * removes the associated nat 'conn' from the lookup datastructures. */
-static void
-conn_clean(struct conntrack *ct, struct conn *conn)
-    OVS_REQUIRES(ct->ct_lock)
-{
-    ovs_assert(conn->conn_type == CT_CONN_TYPE_DEFAULT);
-
-    conn_clean_cmn(ct, conn);
     if (conn->nat_conn) {
-        uint32_t hash = conn_key_hash(&conn->nat_conn->key, ct->hash_basis);
+        hash = conn_key_hash(&conn->nat_conn->key, ct->hash_basis);
         cmap_remove(&ct->conns, &conn->nat_conn->cm_node, hash);
     }
     ovs_list_remove(&conn->exp_node);
@@ -479,19 +470,6 @@ conn_clean(struct conntrack *ct, struct conn *conn)
     atomic_count_dec(&ct->n_conn);
 }
 
-static void
-conn_clean_one(struct conntrack *ct, struct conn *conn)
-    OVS_REQUIRES(ct->ct_lock)
-{
-    conn_clean_cmn(ct, conn);
-    if (conn->conn_type == CT_CONN_TYPE_DEFAULT) {
-        ovs_list_remove(&conn->exp_node);
-        conn->cleaned = true;
-        atomic_count_dec(&ct->n_conn);
-    }
-    ovsrcu_postpone(delete_conn_one, conn);
-}
-
 /* Destroys the connection tracker 'ct' and frees all the allocated memory.
  * The caller of this function must already have shut down packet input
  * and PMD threads (which would have been quiesced).  */
@@ -505,7 +483,11 @@ conntrack_destroy(struct conntrack *ct)
 
     ovs_mutex_lock(&ct->ct_lock);
     CMAP_FOR_EACH (conn, cm_node, &ct->conns) {
-        conn_clean_one(ct, conn);
+        if (conn->conn_type != CT_CONN_TYPE_DEFAULT) {
+            continue;
+        }
+
+        conn_clean(ct, conn);
     }
     cmap_destroy(&ct->conns);
 
@@ -1009,7 +991,7 @@ conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
 nat_res_exhaustion:
     free(nat_conn);
     ovs_list_remove(&nc->exp_node);
-    delete_conn_cmn(nc);
+    delete_conn__(nc);
     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
     VLOG_WARN_RL(&rl, "Unable to NAT due to tuple space exhaustion - "
                  "if DoS attack, use firewalling and/or zone partitioning.");
@@ -2475,7 +2457,7 @@ new_conn(struct conntrack *ct, struct dp_packet *pkt, struct conn_key *key,
 }
 
 static void
-delete_conn_cmn(struct conn *conn)
+delete_conn__(struct conn *conn)
 {
     free(conn->alg);
     free(conn);
@@ -2487,17 +2469,7 @@ delete_conn(struct conn *conn)
     ovs_assert(conn->conn_type == CT_CONN_TYPE_DEFAULT);
     ovs_mutex_destroy(&conn->lock);
     free(conn->nat_conn);
-    delete_conn_cmn(conn);
-}
-
-/* Only used by conn_clean_one(). */
-static void
-delete_conn_one(struct conn *conn)
-{
-    if (conn->conn_type == CT_CONN_TYPE_DEFAULT) {
-        ovs_mutex_destroy(&conn->lock);
-    }
-    delete_conn_cmn(conn);
+    delete_conn__(conn);
 }
 
 /* Convert a conntrack address 'a' into an IP address 'b' based on 'dl_type'.
@@ -2673,8 +2645,12 @@ conntrack_flush(struct conntrack *ct, const uint16_t *zone)
 
     ovs_mutex_lock(&ct->ct_lock);
     CMAP_FOR_EACH (conn, cm_node, &ct->conns) {
+        if (conn->conn_type != CT_CONN_TYPE_DEFAULT) {
+            continue;
+        }
+
         if (!zone || *zone == conn->key.zone) {
-            conn_clean_one(ct, conn);
+            conn_clean(ct, conn);
         }
     }
     ovs_mutex_unlock(&ct->ct_lock);