Introduce IFCAP_VLAN_HWOFFLOAD for vio(4).

Add IFCAP_VLAN_HWOFFLOAD to signal hardware like vio(4) can handle
checksum or TSO offloading with inline VLAN tags.

tested by Mark Patruck, sf@ and bluhm@

ok sf@ and bluhm@

2 files changed, 7 insertions, 4 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index bc92b15c567..121bb1e8f75 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ifconfig.8,v 1.399 2024/01/11 17:22:04 jan Exp $
+.\"	$OpenBSD: ifconfig.8,v 1.400 2024/06/09 16:25:27 jan Exp $
 .\"	$NetBSD: ifconfig.8,v 1.11 1996/01/04 21:27:29 pk Exp $
 .\"     $FreeBSD: ifconfig.8,v 1.16 1998/02/01 07:03:29 steve Exp $
 .\"
@@ -31,7 +31,7 @@
 .\"
 .\"     @(#)ifconfig.8	8.4 (Berkeley) 6/1/94
 .\"
-.Dd $Mdocdate: January 11 2024 $
+.Dd $Mdocdate: June 9 2024 $
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -294,6 +294,9 @@ tag.
 On transmit, the device can add the
 .Xr vlan 4
 tag.
+.It Sy VLAN_HWOFFLOAD
+On transmit, the device can handle checksum or TSO offload without
+.Sy VLAN_HWTAGGING .
 .It Sy WOL
 The device supports Wake on LAN (WoL).
 .It Sy hardmtu
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index 2c257a430a2..3e44dce7120 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ifconfig.c,v 1.472 2024/05/18 02:44:22 jsg Exp $	*/
+/*	$OpenBSD: ifconfig.c,v 1.473 2024/06/09 16:25:27 jan Exp $	*/
 /*	$NetBSD: ifconfig.c,v 1.40 1997/10/01 02:19:43 enami Exp $	*/
 
 /*
@@ -125,7 +125,7 @@
 
 #define HWFEATURESBITS							\
 	"\024\1CSUM_IPv4\2CSUM_TCPv4\3CSUM_UDPv4"			\
-	"\5VLAN_MTU\6VLAN_HWTAGGING\10CSUM_TCPv6"			\
+	"\5VLAN_MTU\6VLAN_HWTAGGING\7VLAN_HWOFFLOAD\10CSUM_TCPv6"	\
 	"\11CSUM_UDPv6\15TSOv4\16TSOv6\17LRO\20WOL"
 
 struct ifencap {