diff --git a/lightningd/connection.c b/lightningd/connection.c
index 5a92ebaed..8ea146e23 100644
--- a/lightningd/connection.c
+++ b/lightningd/connection.c
@@ -46,7 +46,7 @@ void daemon_conn_init(tal_t *ctx, struct daemon_conn *dc, int fd,
 	io_new_conn(ctx, fd, daemon_conn_start, dc);
 }
 
-void daemon_conn_send(struct daemon_conn *dc, u8 *msg)
+void daemon_conn_send(struct daemon_conn *dc, const u8 *msg)
 {
 	msg_enqueue(&dc->out, msg);
 	io_wake(dc);
diff --git a/lightningd/connection.h b/lightningd/connection.h
index d30df1be0..8f05b08dd 100644
--- a/lightningd/connection.h
+++ b/lightningd/connection.h
@@ -44,7 +44,7 @@ void daemon_conn_init(tal_t *ctx, struct daemon_conn *dc, int fd,
 /**
  * daemon_conn_send - Enqueue an outgoing message to be sent
  */
-void daemon_conn_send(struct daemon_conn *dc, u8 *msg);
+void daemon_conn_send(struct daemon_conn *dc, const u8 *msg);
 
 /**
  * daemon_conn_write_next - Continue writing from the msg-queue