4736ccfd9c
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195 lines
5.8 KiB
C
195 lines
5.8 KiB
C
/* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc Exp $ */
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 1999 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/*
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* ECN consideration on tunnel ingress/egress operation.
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* http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/errno.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#ifdef INET6
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#include <netinet/ip6.h>
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#endif
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#include <netinet/ip_ecn.h>
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#ifdef INET6
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#include <netinet6/ip6_ecn.h>
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#endif
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/*
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* ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and
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* decapsulation from RFC3168:
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*
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* Outer Hdr at Inner Hdr at
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* Encapsulator Decapsulator
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* Header fields: -------------------- ------------
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* DS Field copied from inner hdr no change
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* ECN Field constructed by (I) constructed by (E)
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*
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* ECN_ALLOWED (full functionality):
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* (I) if the ECN field in the inner header is set to CE, then set the
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* ECN field in the outer header to ECT(0).
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* otherwise, copy the ECN field to the outer header.
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*
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* (E) if the ECN field in the outer header is set to CE and the ECN
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* field of the inner header is not-ECT, drop the packet.
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* if the ECN field in the inner header is set to ECT(0) or ECT(1)
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* and the ECN field in the outer header is set to CE, then copy CE to
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* the inner header. otherwise, make no change to the inner header.
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*
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* ECN_FORBIDDEN (limited functionality):
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* (I) set the ECN field to not-ECT in the outer header.
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*
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* (E) if the ECN field in the outer header is set to CE, drop the packet.
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* otherwise, make no change to the ECN field in the inner header.
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*
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* the drop rule is for backward compatibility and protection against
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* erasure of CE.
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*/
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/*
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* modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
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*/
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void
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ip_ecn_ingress(int mode, u_int8_t *outer, const u_int8_t *inner)
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{
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if (!outer || !inner)
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panic("NULL pointer passed to ip_ecn_ingress");
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*outer = *inner;
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switch (mode) {
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case ECN_ALLOWED: /* ECN allowed */
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/*
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* full-functionality: if the inner is CE, set ECT(0)
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* to the outer. otherwise, copy the ECN field.
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*/
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if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
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*outer &= ~IPTOS_ECN_ECT1;
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break;
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case ECN_FORBIDDEN: /* ECN forbidden */
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/*
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* limited-functionality: set not-ECT to the outer
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*/
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*outer &= ~IPTOS_ECN_MASK;
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break;
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case ECN_NOCARE: /* no consideration to ECN */
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break;
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}
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}
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/*
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* modify inner ECN (TOS) field on egress operation (tunnel decapsulation).
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* the caller should drop the packet if the return value is 0.
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*/
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int
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ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner)
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{
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if (!outer || !inner)
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panic("NULL pointer passed to ip_ecn_egress");
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switch (mode) {
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case ECN_ALLOWED:
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/*
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* full-functionality: if the outer is CE and the inner is
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* not-ECT, should drop it. otherwise, copy CE.
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*/
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if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) {
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if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
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return (0);
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*inner |= IPTOS_ECN_CE;
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}
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break;
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case ECN_FORBIDDEN: /* ECN forbidden */
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/*
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* limited-functionality: if the outer is CE, should drop it.
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* otherwise, leave the inner.
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*/
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if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
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return (0);
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break;
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case ECN_NOCARE: /* no consideration to ECN */
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break;
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}
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return (1);
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}
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#ifdef INET6
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void
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ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner)
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{
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u_int8_t outer8, inner8;
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if (!outer || !inner)
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panic("NULL pointer passed to ip6_ecn_ingress");
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inner8 = (ntohl(*inner) >> 20) & 0xff;
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ip_ecn_ingress(mode, &outer8, &inner8);
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*outer &= ~htonl(0xff << 20);
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*outer |= htonl((u_int32_t)outer8 << 20);
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}
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int
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ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner)
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{
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u_int8_t outer8, inner8, oinner8;
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if (!outer || !inner)
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panic("NULL pointer passed to ip6_ecn_egress");
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outer8 = (ntohl(*outer) >> 20) & 0xff;
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inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff;
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if (ip_ecn_egress(mode, &outer8, &inner8) == 0)
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return (0);
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if (inner8 != oinner8) {
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*inner &= ~htonl(0xff << 20);
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*inner |= htonl((u_int32_t)inner8 << 20);
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}
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return (1);
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}
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#endif
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