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/* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 1999 WIDE Project.
* 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.
* 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
*
*/
/*
* ECN consideration on tunnel ingress/egress operation.
* http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/ip_ecn.h>
#ifdef INET6
#include <netinet6/ip6_ecn.h>
#endif
/*
* ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and
* decapsulation from RFC3168:
*
* Outer Hdr at Inner Hdr at
* Encapsulator Decapsulator
* Header fields: -------------------- ------------
* DS Field copied from inner hdr no change
* ECN Field constructed by (I) constructed by (E)
*
* ECN_ALLOWED (full functionality):
* (I) if the ECN field in the inner header is set to CE, then set the
* ECN field in the outer header to ECT(0).
* otherwise, copy the ECN field to the outer header.
*
* (E) if the ECN field in the outer header is set to CE and the ECN
* field of the inner header is not-ECT, drop the packet.
* if the ECN field in the inner header is set to ECT(0) or ECT(1)
* and the ECN field in the outer header is set to CE, then copy CE to
* the inner header. otherwise, make no change to the inner header.
*
* ECN_FORBIDDEN (limited functionality):
* (I) set the ECN field to not-ECT in the outer header.
*
* (E) if the ECN field in the outer header is set to CE, drop the packet.
* otherwise, make no change to the ECN field in the inner header.
*
* the drop rule is for backward compatibility and protection against
* erasure of CE.
*/
/*
* modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
*/
void
ip_ecn_ingress(int mode, u_int8_t *outer, const u_int8_t *inner)
{
if (!outer || !inner)
panic("NULL pointer passed to ip_ecn_ingress");
*outer = *inner;
switch (mode) {
case ECN_ALLOWED: /* ECN allowed */
/*
* full-functionality: if the inner is CE, set ECT(0)
* to the outer. otherwise, copy the ECN field.
*/
if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
*outer &= ~IPTOS_ECN_ECT1;
break;
case ECN_FORBIDDEN: /* ECN forbidden */
/*
* limited-functionality: set not-ECT to the outer
*/
*outer &= ~IPTOS_ECN_MASK;
break;
case ECN_NOCARE: /* no consideration to ECN */
break;
}
}
/*
* modify inner ECN (TOS) field on egress operation (tunnel decapsulation).
* the caller should drop the packet if the return value is 0.
*/
int
ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner)
{
if (!outer || !inner)
panic("NULL pointer passed to ip_ecn_egress");
switch (mode) {
case ECN_ALLOWED:
/*
* full-functionality: if the outer is CE and the inner is
* not-ECT, should drop it. otherwise, copy CE.
*/
if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) {
if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
return (0);
*inner |= IPTOS_ECN_CE;
}
break;
case ECN_FORBIDDEN: /* ECN forbidden */
/*
* limited-functionality: if the outer is CE, should drop it.
* otherwise, leave the inner.
*/
if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
return (0);
break;
case ECN_NOCARE: /* no consideration to ECN */
break;
}
return (1);
}
#ifdef INET6
void
ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner)
{
u_int8_t outer8, inner8;
if (!outer || !inner)
panic("NULL pointer passed to ip6_ecn_ingress");
inner8 = (ntohl(*inner) >> 20) & 0xff;
ip_ecn_ingress(mode, &outer8, &inner8);
*outer &= ~htonl(0xff << 20);
*outer |= htonl((u_int32_t)outer8 << 20);
}
int
ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner)
{
u_int8_t outer8, inner8, oinner8;
if (!outer || !inner)
panic("NULL pointer passed to ip6_ecn_egress");
outer8 = (ntohl(*outer) >> 20) & 0xff;
inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff;
if (ip_ecn_egress(mode, &outer8, &inner8) == 0)
return (0);
if (inner8 != oinner8) {
*inner &= ~htonl(0xff << 20);
*inner |= htonl((u_int32_t)inner8 << 20);
}
return (1);
}
#endif
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