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54 lines (48 loc) · 2.07 KB
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/*
* Copyright (c) 2003 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _GRE_
#define _GRE_
struct gre_hdr {
uint16_t gre_flags;
uint16_t gre_proto;
uint16_t gre_sum; /* Optional (RFC 2784) */
uint16_t gre_reserved; /* Optional (RFC 2784) */
} __attribute__((__packed__));
#define GRE_CHECKSUM 0x8000 /* Use the checksum field */
#define GRE_VERSION 0
#define GRE_IP4PROTO 0x800 /* Required by RFC */
#define GRE_NOCKSUM_DATA(x) (u_char *)(&(x)->gre_sum)
int gre_encapsulate(ip_t *, struct addr *, struct addr *,
struct ip_hdr *, u_int);
int gre_decapsulate(struct ip_hdr *, u_short oiplen, struct ip_hdr **,
u_short *);
#endif /* _GRE_ */