diff --git a/flow.c b/flow.c
index 80dd269..e257f89 100644
--- a/flow.c
+++ b/flow.c
@@ -292,17 +292,17 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 			ASSERT(false);
 			break;
 		case FLOW_TCP:
-			closed = tcp_flow_defer(flow);
+			closed = tcp_flow_defer(&flow->tcp);
 			break;
 		case FLOW_TCP_SPLICE:
-			closed = tcp_splice_flow_defer(flow);
+			closed = tcp_splice_flow_defer(&flow->tcp_splice);
 			if (!closed && timer)
-				tcp_splice_timer(c, flow);
+				tcp_splice_timer(c, &flow->tcp_splice);
 			break;
 		case FLOW_PING4:
 		case FLOW_PING6:
 			if (timer)
-				closed = icmp_ping_timer(c, flow, now);
+				closed = icmp_ping_timer(c, &flow->ping, now);
 			break;
 		default:
 			/* Assume other flow types don't need any handling */
diff --git a/icmp.c b/icmp.c
index 1c5cf84..eb559c1 100644
--- a/icmp.c
+++ b/icmp.c
@@ -289,16 +289,14 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 /**
  * icmp_ping_timer() - Handler for timed events related to a given flow
  * @c:		Execution context
- * @flow:	flow table entry to check for timeout
+ * @pingf:	Ping flow to check for timeout
  * @now:	Current timestamp
  *
  * Return: true if the flow is ready to free, false otherwise
  */
-bool icmp_ping_timer(const struct ctx *c, union flow *flow,
+bool icmp_ping_timer(const struct ctx *c, const struct icmp_ping_flow *pingf,
 		     const struct timespec *now)
 {
-	const struct icmp_ping_flow *pingf = &flow->ping;
-
 	if (now->tv_sec - pingf->ts <= ICMP_ECHO_TIMEOUT)
 		return false;
 
diff --git a/icmp_flow.h b/icmp_flow.h
index 5a2eed9..c9847ea 100644
--- a/icmp_flow.h
+++ b/icmp_flow.h
@@ -25,7 +25,7 @@ struct icmp_ping_flow {
 	uint16_t id;
 };
 
-bool icmp_ping_timer(const struct ctx *c, union flow *flow,
+bool icmp_ping_timer(const struct ctx *c, const struct icmp_ping_flow *pingf,
 		     const struct timespec *now);
 
 #endif /* ICMP_FLOW_H */
diff --git a/tcp.c b/tcp.c
index efbbc1c..109d443 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1221,15 +1221,13 @@ static struct tcp_tap_conn *tcp_hash_lookup(const struct ctx *c,
 
 /**
  * tcp_flow_defer() - Deferred per-flow handling (clean up closed connections)
- * @flow:	Flow table entry for this connection
+ * @conn:	Connection to handle
  *
- * Return: true if the flow is ready to free, false otherwise
+ * Return: true if the connection is ready to free, false otherwise
  */
-bool tcp_flow_defer(union flow *flow)
+bool tcp_flow_defer(const struct tcp_tap_conn *conn)
 {
-	const struct tcp_tap_conn *conn = &flow->tcp;
-
-	if (flow->tcp.events != CLOSED)
+	if (conn->events != CLOSED)
 		return false;
 
 	close(conn->sock);
diff --git a/tcp_conn.h b/tcp_conn.h
index d280b22..52bd815 100644
--- a/tcp_conn.h
+++ b/tcp_conn.h
@@ -155,9 +155,9 @@ struct tcp_splice_conn {
 extern int init_sock_pool4	[TCP_SOCK_POOL_SIZE];
 extern int init_sock_pool6	[TCP_SOCK_POOL_SIZE];
 
-bool tcp_flow_defer(union flow *flow);
-bool tcp_splice_flow_defer(union flow *flow);
-void tcp_splice_timer(const struct ctx *c, union flow *flow);
+bool tcp_flow_defer(const struct tcp_tap_conn *conn);
+bool tcp_splice_flow_defer(struct tcp_splice_conn *conn);
+void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn);
 int tcp_conn_pool_sock(int pool[]);
 int tcp_conn_sock(const struct ctx *c, sa_family_t af);
 int tcp_sock_refill_pool(const struct ctx *c, int pool[], sa_family_t af);
diff --git a/tcp_splice.c b/tcp_splice.c
index 4c36b72..fb00bc2 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -235,16 +235,15 @@ static void conn_event_do(const struct ctx *c, struct tcp_splice_conn *conn,
 
 /**
  * tcp_splice_flow_defer() - Deferred per-flow handling (clean up closed)
- * @flow:	Flow table entry for this connection
+ * @conn:	Connection entry to handle
  *
  * Return: true if the flow is ready to free, false otherwise
  */
-bool tcp_splice_flow_defer(union flow *flow)
+bool tcp_splice_flow_defer(struct tcp_splice_conn *conn)
 {
-	struct tcp_splice_conn *conn = &flow->tcp_splice;
 	unsigned side;
 
-	if (!(flow->tcp_splice.flags & CLOSING))
+	if (!(conn->flags & CLOSING))
 		return false;
 
 	for (side = 0; side < SIDES; side++) {
@@ -786,11 +785,10 @@ void tcp_splice_init(struct ctx *c)
 /**
  * tcp_splice_timer() - Timer for spliced connections
  * @c:		Execution context
- * @flow:	Flow table entry
+ * @conn:	Connection to handle
  */
-void tcp_splice_timer(const struct ctx *c, union flow *flow)
+void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn)
 {
-	struct tcp_splice_conn *conn = &flow->tcp_splice;
 	int side;
 
 	ASSERT(!(conn->flags & CLOSING));