FreeBSD/Linux Kernel Cross Reference
sys/net/if_gre.h

     /*      $OpenBSD: if_gre.h,v 1.16 2021/03/10 10:21:48 jsg Exp $ */
     /*      $NetBSD: if_gre.h,v 1.5 1999/11/19 20:41:19 thorpej 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.
     *
     * 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
    
    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 fields (see below)
                                 Present if (rt_pres == 1)
    */
    } __packed;
    
    struct greip {
            struct ip gi_i;
            struct gre_h  gi_g;
    } __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 */
    
    /* 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;   /* address 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 */
   } __packed;
   
   struct mobip_h {
           struct ip       mi;
           struct mobile_h mh;
   } __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
   
   #ifdef _KERNEL
   int     gre_sysctl(int *, u_int, void *, size_t *, void *, size_t);
   int     gre_input(struct mbuf **, int *, int, int);
   int     gre_input6(struct mbuf **, int *, int, int);
   #endif
   #endif /* _NET_IF_GRE_H_ */

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