flow: Make unified version of flow table compaction

tcp_table_compact() will move entries in the connection/flow table to keep
it compact when other entries are removed.  The moved entries need not have
the same type as the flow removed, so it needs to be able to handle moving
any type of flow.  Therefore, move it to flow.c rather than being
purportedly TCP specific.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

flow.c

@@ -27,3 +27,42 @@ static_assert(ARRAY_SIZE(flow_type_str) == FLOW_NUM_TYPES,
 
 /* Global Flow Table */
 union flow flowtab[FLOW_MAX];
+
+/**
+ * flow_table_compact() - Perform compaction on flow table
+ * @c:		Execution context
+ * @hole:	Pointer to recently closed flow
+ */
+void flow_table_compact(struct ctx *c, union flow *hole)
+{
+	union flow *from;
+
+	if (FLOW_IDX(hole) == --c->flow_count) {
+		debug("flow: table compaction: maximum index was %u (%p)",
+		      FLOW_IDX(hole), (void *)hole);
+		memset(hole, 0, sizeof(*hole));
+		return;
+	}
+
+	from = flowtab + c->flow_count;
+	memcpy(hole, from, sizeof(*hole));
+
+	switch (from->f.type) {
+	case FLOW_TCP:
+		tcp_tap_conn_update(c, &from->tcp, &hole->tcp);
+		break;
+	case FLOW_TCP_SPLICE:
+		tcp_splice_conn_update(c, &hole->tcp_splice);
+		break;
+	default:
+		die("Unexpected %s in tcp_table_compact()",
+		    FLOW_TYPE(&from->f));
+	}
+
+	debug("flow: table compaction (%s): old index %u, new index %u, "
+	      "from: %p, to: %p",
+	      FLOW_TYPE(&from->f), FLOW_IDX(from), FLOW_IDX(hole),
+	      (void *)from, (void *)hole);
+
+	memset(from, 0, sizeof(*from));
+}

flow.h

@@ -41,4 +41,6 @@ struct flow_common {
 
 union flow;
 
+void flow_table_compact(struct ctx *c, union flow *hole);
+
 #endif /* FLOW_H */

tcp.c

@@ -1244,8 +1244,9 @@ static void tcp_hash_remove(const struct ctx *c,
  * @old:	Old location of tcp_tap_conn
  * @new:	New location of tcp_tap_conn
  */
-static void tcp_tap_conn_update(const struct ctx *c, struct tcp_tap_conn *old,
+void tcp_tap_conn_update(const struct ctx *c, struct tcp_tap_conn *old,
 			 struct tcp_tap_conn *new)
+
 {
 	struct tcp_tap_conn *entry, *prev = NULL;
 	int b = tcp_conn_hash(c, old);
@@ -1297,45 +1298,6 @@ static struct tcp_tap_conn *tcp_hash_lookup(const struct ctx *c,
 	return NULL;
 }
 
-/**
- * tcp_table_compact() - Perform compaction on connection table
- * @c:		Execution context
- * @hole:	Pointer to recently closed connection
- */
-void tcp_table_compact(struct ctx *c, union flow *hole)
-{
-	union flow *from;
-
-	if (FLOW_IDX(hole) == --c->flow_count) {
-		debug("TCP: table compaction: maximum index was %u (%p)",
-		      FLOW_IDX(hole), (void *)hole);
-		memset(hole, 0, sizeof(*hole));
-		return;
-	}
-
-	from = flowtab + c->flow_count;
-	memcpy(hole, from, sizeof(*hole));
-
-	switch (from->f.type) {
-	case FLOW_TCP:
-		tcp_tap_conn_update(c, &from->tcp, &hole->tcp);
-		break;
-	case FLOW_TCP_SPLICE:
-		tcp_splice_conn_update(c, &hole->tcp_splice);
-		break;
-	default:
-		die("Unexpected %s in tcp_table_compact()",
-		    FLOW_TYPE(&from->f));
-	}
-
-	debug("TCP: table compaction (%s): old index %u, new index %u, "
-	      "from: %p, to: %p",
-	      FLOW_TYPE(&from->f), FLOW_IDX(from), FLOW_IDX(hole),
-	      (void *)from, (void *)hole);
-
-	memset(from, 0, sizeof(*from));
-}
-
 /**
  * tcp_conn_destroy() - Close sockets, trigger hash table removal and compaction
  * @c:		Execution context
@@ -1350,7 +1312,7 @@ static void tcp_conn_destroy(struct ctx *c, union flow *flow)
 		close(conn->timer);
 
 	tcp_hash_remove(c, conn);
-	tcp_table_compact(c, flow);
+	flow_table_compact(c, flow);
 }
 
 static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);

tcp_conn.h

@@ -157,8 +157,9 @@ struct tcp_splice_conn {
 extern int init_sock_pool4	[TCP_SOCK_POOL_SIZE];
 extern int init_sock_pool6	[TCP_SOCK_POOL_SIZE];
 
+void tcp_tap_conn_update(const struct ctx *c, struct tcp_tap_conn *old,
+			 struct tcp_tap_conn *new);
 void tcp_splice_conn_update(const struct ctx *c, struct tcp_splice_conn *new);
-void tcp_table_compact(struct ctx *c, union flow *hole);
 void tcp_splice_destroy(struct ctx *c, union flow *flow);
 void tcp_splice_timer(struct ctx *c, union flow *flow);
 int tcp_conn_pool_sock(int pool[]);

tcp_splice.c

@@ -283,7 +283,7 @@ void tcp_splice_destroy(struct ctx *c, union flow *flow)
 	conn->flags = 0;
 	debug("TCP (spliced): index %u, CLOSED", FLOW_IDX(conn));
 
-	tcp_table_compact(c, flow);
+	flow_table_compact(c, flow);
 }
 
 /**