diff --git a/include/types/connection.h b/include/types/connection.h
index 3dab54e..6cd8a3a 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -269,7 +269,7 @@
  */
 struct xprt_ops {
 	int  (*rcv_buf)(struct connection *conn, struct buffer *buf, int count); /* recv callback */
-	int  (*snd_buf)(struct connection *conn, struct buffer *buf, int flags); /* send callback */
+	size_t (*snd_buf)(struct connection *conn, const struct buffer *buf, size_t count, int flags); /* send callback */
 	int  (*rcv_pipe)(struct connection *conn, struct pipe *pipe, unsigned int count); /* recv-to-pipe callback */
 	int  (*snd_pipe)(struct connection *conn, struct pipe *pipe); /* send-to-pipe callback */
 	void (*shutr)(struct connection *, int);    /* shutr function */