freebsd-skq/sys/net/if_tap.h
Vincenzo Maffione f8bc74e2f4 tap: add support for virtio-net offloads
This patch is part of an effort to make bhyve networking (in particular TCP)
faster. The key strategy to enhance TCP throughput is to let the whole packet
datapath work with TSO/LRO packets (up to 64KB each), so that the per-packet
overhead is amortized over a large number of bytes.
This capability is supported in the guest by means of the vtnet(4) driver,
which is able to handle TSO/LRO packets leveraging the virtio-net header
(see struct virtio_net_hdr and struct virtio_net_hdr_mrg_rxbuf).
A bhyve VM exchanges packets with the host through a network backend,
which can be vale(4) or if_tap(4).
While vale(4) supports TSO/LRO packets, if_tap(4) does not.
This patch extends if_tap(4) with the ability to understand the virtio-net
header, so that a tapX interface can process TSO/LRO packets.
A couple of ioctl commands have been added to configure and probe the
virtio-net header. Once the virtio-net header is set, the tapX interface
acquires all the IFCAP capabilities necessary for TSO/LRO.

Reviewed by:	kevans
Differential Revision:	https://reviews.freebsd.org/D21263
2019-10-18 21:53:27 +00:00

77 lines
2.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (C) 1999-2000 by Maksim Yevmenkin <m_evmenkin@yahoo.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* BASED ON:
* -------------------------------------------------------------------------
*
* Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk>
* Nottingham University 1987.
*/
/*
* $FreeBSD$
* $Id: if_tap.h,v 0.7 2000/07/12 04:12:51 max Exp $
*/
#ifndef _NET_IF_TAP_H_
#define _NET_IF_TAP_H_
#include <net/if_tun.h>
/* maximum receive packet size (hard limit) */
#define TAPMRU 65535
#define tapinfo tuninfo
/*
* ioctl's for get/set debug; these are aliases of TUN* ioctls, see net/if_tun.h
* for details.
*/
#define TAPSDEBUG TUNSDEBUG
#define TAPGDEBUG TUNGDEBUG
#define TAPSIFINFO TUNSIFINFO
#define TAPGIFINFO TUNGIFINFO
#define TAPGIFNAME TUNGIFNAME
#define TAPSVNETHDR _IOW('t', 91, int)
#define TAPGVNETHDR _IOR('t', 94, int)
/* VMware ioctl's */
#define VMIO_SIOCSIFFLAGS _IOWINT('V', 0)
#define VMIO_SIOCSKEEP _IO('V', 1)
#define VMIO_SIOCSIFBR _IO('V', 2)
#define VMIO_SIOCSLADRF _IO('V', 3)
/* XXX -- unimplemented */
#define VMIO_SIOCSETMACADDR _IO('V', 4)
/* XXX -- not used? */
#define VMIO_SIOCPORT _IO('V', 5)
#define VMIO_SIOCBRIDGE _IO('V', 6)
#define VMIO_SIOCNETIF _IO('V', 7)
#endif /* !_NET_IF_TAP_H_ */