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/* $OpenBSD: if_tun.h,v 1.16 2024/11/14 01:51:57 dlg Exp $ */
/*
* Copyright (c) 1988, Julian Onions <Julian.Onions@nexor.co.uk>
* Nottingham University 1987.
* 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 ``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 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.
*/
#ifndef _NET_IF_TUN_H_
#define _NET_IF_TUN_H_
#include <sys/ioccom.h>
/*
* tun_hdr is a multiple of 4 bytes, but is built out of uint16_t
* fields. This allows it to sit on a 2 byte boundary in front of
* either IP (and MPLS) or Ethernet packets for tun(4) and tap(4)
* interfaces respectively while maintaining the alignment of their
* payloads.
*
* Userland can request the use of the tun_hdr using the TUNSCAP
* ioctl. This ioctl also allows userland to specify which "offload"
* capabilities it is able to accept in packets it will read from the
* kernel. It is acceptable to enable tun_hdr without enabling any
* interface offload capabilities.
*
* Once the tap_hdr is enabled, userland can write packets into the
* kernel with any of the supported features. tun(4)/tap(4) reads
* will unconditionally handle any features specified on the packet,
* regardless of what capabilities were specified by the TUNSCAP
* ioctl.
*
* The tun_hdr can be read from one interface and written directly
* to another without interpretation or modification.
*
* Use of tun_hdr and the associated capabilities are reset when a
* tun(4)/tap(4) device is closed.
*/
struct tun_hdr {
uint16_t th_flags;
#define TUN_H_VTAG (1 << 0) /* th_vtag is set */
#define TUN_H_TCP_MSS (1 << 1) /* Cut TCP frame up by th_mss */
#define TUN_H_IPV4_CSUM (1 << 8)
#define TUN_H_TCP_CSUM (1 << 9)
#define TUN_H_UDP_CSUM (1 << 10)
#define TUN_H_ICMP_CSUM (1 << 11)
uint16_t th_pad;
uint16_t th_vtag;
uint16_t th_mss;
};
#define TUN_OPEN 0x0001
#define TUN_INITED 0x0002
#define TUN_RCOLL 0x0004 /* unused */
#define TUN_IASET 0x0008
#define TUN_DSTADDR 0x0010
#define TUN_RWAIT 0x0040
#define TUN_ASYNC 0x0080
#define TUN_NBIO 0x0100
#define TUN_BRDADDR 0x0200
#define TUN_STAYUP 0x0400
#define TUN_LAYER2 0x0800
#define TUN_READY (TUN_OPEN | TUN_INITED)
/* Maximum packet size */
#define TUNMTU 3000
/* Maximum receive packet size (hard limit) */
#define TUNMRU 16384
/* iface info */
struct tuninfo {
u_int mtu;
u_short type;
u_short flags;
u_int baudrate;
};
#define TUNSIFINFO _IOW('t', 91, struct tuninfo)
#define TUNGIFINFO _IOR('t', 92, struct tuninfo)
/* ioctl for changing the broadcast/point-to-point status */
#define TUNSIFMODE _IOW('t', 93, int)
/* ioctl's for get/set debug */
#define TUNSDEBUG _IOW('t', 94, int)
#define TUNGDEBUG _IOR('t', 95, int)
struct tun_capabilities {
uint32_t tun_if_capabilities; /* IFCAP_* from net/if.h */
};
#define TUNSCAP _IOW('t', 96, struct tun_capabilities)
#define TUNGCAP _IOR('t', 96, struct tun_capabilities)
#define TUNDCAP _IO('t', 96)
#endif /* _NET_IF_TUN_H_ */
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