diff --git a/include/proto/channel.h b/include/proto/channel.h
index b281119..9e02dc0 100644
--- a/include/proto/channel.h
+++ b/include/proto/channel.h
@@ -304,7 +304,7 @@
 	    chn->to_forward == CHN_INFINITE_FORWARD)
 		goto end;
 
-	transit = chn->to_forward - chn->buf->i;
+	transit = chn->buf->o + chn->to_forward - chn->buf->i;
 	if (transit < 0)
 		transit = 0;