text: /*	$NetBSD: if_gre.h,v 1.10 2002/02/24 17:22:20 martin Exp $ */
  /*	$FreeBSD: src/sys/net/if_gre.h,v 1.6.2.2 2002/12/03 01:17:52 peter Exp $ */
  
  /*
   * Copyright (c) 1998 The NetBSD Foundation, Inc.
   * All rights reserved
   *
   * This code is derived from software contributed to The NetBSD Foundation
   * by Heiko W.Rupp <hwr@pilhuhn.de>
   *
   * 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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *        This product includes software developed by the NetBSD
   *        Foundation, Inc. and its contributors.
   * 4. Neither the name of The NetBSD Foundation nor the names of its
   *    contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *    
   * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
   */
  
  #ifndef _NET_IF_GRE_H
  #define _NET_IF_GRE_H
  
  #include <sys/ioccom.h>
  #ifdef _KERNEL
  #include <sys/queue.h>
  
  struct gre_softc {
  	struct ifnet sc_if;
  	LIST_ENTRY(gre_softc) sc_list;
  	int gre_unit;
  	int gre_flags;
  	struct in_addr g_src;	/* source address of gre packets */
  	struct in_addr g_dst;	/* destination address of gre packets */
  	struct route route;	/* routing entry that determines, where a
  				   encapsulated packet should go */
  	u_char g_proto;		/* protocol of encapsulator */
  
  	const struct encaptab *encap;	/* encapsulation cookie */
  
  	int called;		/* infinite recursion preventer */
  
  	struct resource *r_unit;/* resource allocated for this unit */
  };	
  
  
  struct gre_h {
  	u_int16_t flags;	/* GRE flags */
  	u_int16_t ptype;	/* protocol type of payload typically 
  				   Ether protocol type*/
  /* 
   *  from here on: fields are optional, presence indicated by flags 
   *
  	u_int_16 checksum	checksum (one-complements of GRE header
  				and payload
  				Present if (ck_pres | rt_pres == 1).
  				Valid if (ck_pres == 1).
  	u_int_16 offset		offset from start of routing filed to
  				first octet of active SRE (see below).
  				Present if (ck_pres | rt_pres == 1).
  				Valid if (rt_pres == 1).
  	u_int_32 key		inserted by encapsulator e.g. for
  				authentication
  				Present if (key_pres ==1 ).
  	u_int_32 seq_num	Sequence number to allow for packet order
  				Present if (seq_pres ==1 ).
  	struct gre_sre[] routing Routing fileds (see below)
  				Present if (rt_pres == 1)
   */
  } __attribute__((__packed__));
  
  struct greip {
  	struct ip gi_i;
  	struct gre_h  gi_g;
  } __attribute__((__packed__));
  
  #define gi_pr		gi_i.ip_p
  #define gi_len		gi_i.ip_len
  #define gi_src		gi_i.ip_src
  #define gi_dst		gi_i.ip_dst
  #define gi_ptype	gi_g.ptype
  #define gi_flags	gi_g.flags
  
  #define GRE_CP		0x8000  /* Checksum Present */
  #define GRE_RP		0x4000  /* Routing Present */
  #define GRE_KP		0x2000  /* Key Present */
  #define GRE_SP		0x1000  /* Sequence Present */
  #define GRE_SS		0x0800	/* Strict Source Route */
  
  /*
   * CISCO uses special type for GRE tunnel created as part of WCCP
   * connection, while in fact those packets are just IPv4 encapsulated
   * into GRE.
   */
  #define WCCP_PROTOCOL_TYPE	0x883E
  
  /*
   * gre_sre defines a Source route Entry. These are needed if packets
   * should be routed over more than one tunnel hop by hop
   */
  struct gre_sre {
  	u_int16_t sre_family;	/* adress family */
  	u_char	sre_offset;	/* offset to first octet of active entry */
  	u_char	sre_length;	/* number of octets in the SRE. 
  				   sre_lengthl==0 -> last entry. */
  	u_char	*sre_rtinfo;	/* the routing information */
  };
  
  struct greioctl {
  	int unit;
  	struct in_addr addr;
  };
  
  /* for mobile encaps */
  
  struct mobile_h {
  	u_int16_t proto;		/* protocol and S-bit */
  	u_int16_t hcrc;			/* header checksum */
  	u_int32_t odst;			/* original destination address */
  	u_int32_t osrc;			/* original source addr, if S-bit set */
  } __attribute__((__packed__));
  
  struct mobip_h {
  	struct ip	mi;
  	struct mobile_h	mh;
  } __attribute__((__packed__));
  
  
  #define MOB_H_SIZ_S		(sizeof(struct mobile_h) - sizeof(u_int32_t))
  #define MOB_H_SIZ_L		(sizeof(struct mobile_h))
  #define MOB_H_SBIT	0x0080
  
  #define	GRE_TTL	30
  
  #endif /* _KERNEL */
  
  /* 
   * ioctls needed to manipulate the interface 
   */
  
  #define GRESADDRS	_IOW('i', 101, struct ifreq)
  #define GRESADDRD	_IOW('i', 102, struct ifreq)   
  #define GREGADDRS	_IOWR('i', 103, struct ifreq)
  #define GREGADDRD	_IOWR('i', 104, struct ifreq)
  #define GRESPROTO	_IOW('i' , 105, struct ifreq)
  #define GREGPROTO	_IOWR('i', 106, struct ifreq)
  
  #ifdef _KERNEL
  LIST_HEAD(gre_softc_head, gre_softc);
  extern struct gre_softc_head gre_softc_list;
  
  u_short	gre_in_cksum(u_short *p, u_int len);
  #endif /* _KERNEL */
  
  #endif
  