diff --git a/control.c b/control.c
index 0aabe15..2683cf9 100644
--- a/control.c
+++ b/control.c
@@ -592,7 +592,7 @@ static int process_stream_data(struct bufferevent *bev,
 	return 0;
 }
 
-static void handle_tcp_mux_message(const struct tcp_mux_header *tmux_hdr,
+static void handle_tcp_mux_message(struct tcp_mux_header *tmux_hdr,
 								 struct tmux_stream *cur)
 {
 	if (cur == &abandon_stream) {