From 658b7d4eac1c975025e572a07707fa5e129f0f4e Mon Sep 17 00:00:00 2001
From: riastradh <riastradh@NetBSD.org>
Date: Thu, 27 Aug 2020 02:55:04 +0000
Subject: [PATCH] wg: Drop invalid message types on the floor faster.

Don't even let them reach the thread -- drop them in softint.
---
 sys/net/if_wg.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/sys/net/if_wg.c b/sys/net/if_wg.c
index a5e6961adf5a..aebbd7833897 100644
--- a/sys/net/if_wg.c
+++ b/sys/net/if_wg.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: if_wg.c,v 1.27 2020/08/27 02:54:31 riastradh Exp $	*/
+/*	$NetBSD: if_wg.c,v 1.28 2020/08/27 02:55:04 riastradh Exp $	*/
 
 /*
  * Copyright (C) Ryota Ozaki <ozaki.ryota@gmail.com>
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.27 2020/08/27 02:54:31 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.28 2020/08/27 02:55:04 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -2934,6 +2934,7 @@ wg_overudp_cb(struct mbuf **mp, int offset, struct socket *so,
 	/* Verify the mbuf chain is long enough to have a wg msg header.  */
 	KASSERT(offset <= m_length(m));
 	if (__predict_false(m_length(m) - offset < sizeof(struct wg_msg))) {
+		/* drop on the floor */
 		m_freem(m);
 		return -1;
 	}
@@ -2952,15 +2953,21 @@ wg_overudp_cb(struct mbuf **mp, int offset, struct socket *so,
 	 */
 	switch (wgm.wgm_type) {
 	case WG_MSG_TYPE_DATA:
+		/* handle immediately */
 		m_adj(m, offset);
 		wg_handle_msg_data(wg, m, src);
 		*mp = NULL;
 		return 1;
+	case WG_MSG_TYPE_INIT:
+	case WG_MSG_TYPE_RESP:
+	case WG_MSG_TYPE_COOKIE:
+		/* pass through to so_receive in wg_receive_packets */
+		return 0;
 	default:
-		break;
+		/* drop on the floor */
+		m_freem(m);
+		return -1;
 	}
-
-	return 0;
 }
 
 static int