diff --git a/src/backend.c b/src/backend.c
index 17e4b7f..e40b560 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -298,14 +298,11 @@
 	struct http_msg *msg  = &txn->req;
 	struct proxy    *px   = s->be;
 	unsigned int     plen = px->url_param_len;
-	unsigned long    len  = msg->body_len;
+	unsigned long    len  = http_body_bytes(msg);
 	const char      *params = b_ptr(req->buf, (int)(msg->sov + msg->sol - req->buf->o));
 	const char      *p    = params;
 	const char      *start, *end;
 
-	if (len > buffer_len(req->buf) - msg->sov - msg->sol)
-		len = buffer_len(req->buf) - msg->sov - msg->sol;
-
 	if (len == 0)
 		return NULL;