2 /* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc Exp $ */
5 * Copyright (C) 1999 WIDE Project.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * ECN consideration on tunnel ingress/egress operation.
35 * http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt
39 #include "opt_inet6.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
44 #include <sys/errno.h>
46 #include <netinet/in.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/ip.h>
50 #include <netinet/ip6.h>
53 #include <netinet/ip_ecn.h>
55 #include <netinet6/ip6_ecn.h>
59 * ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and
60 * decapsulation from RFC3168:
62 * Outer Hdr at Inner Hdr at
63 * Encapsulator Decapsulator
64 * Header fields: -------------------- ------------
65 * DS Field copied from inner hdr no change
66 * ECN Field constructed by (I) constructed by (E)
68 * ECN_ALLOWED (full functionality):
69 * (I) if the ECN field in the inner header is set to CE, then set the
70 * ECN field in the outer header to ECT(0).
71 * otherwise, copy the ECN field to the outer header.
73 * (E) if the ECN field in the outer header is set to CE and the ECN
74 * field of the inner header is not-ECT, drop the packet.
75 * if the ECN field in the inner header is set to ECT(0) or ECT(1)
76 * and the ECN field in the outer header is set to CE, then copy CE to
77 * the inner header. otherwise, make no change to the inner header.
79 * ECN_FORBIDDEN (limited functionality):
80 * (I) set the ECN field to not-ECT in the outer header.
82 * (E) if the ECN field in the outer header is set to CE, drop the packet.
83 * otherwise, make no change to the ECN field in the inner header.
85 * the drop rule is for backward compatibility and protection against
90 * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
93 ip_ecn_ingress(int mode, u_int8_t *outer, const u_int8_t *inner)
97 panic("NULL pointer passed to ip_ecn_ingress");
101 case ECN_ALLOWED: /* ECN allowed */
103 * full-functionality: if the inner is CE, set ECT(0)
104 * to the outer. otherwise, copy the ECN field.
106 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
107 *outer &= ~IPTOS_ECN_ECT1;
109 case ECN_FORBIDDEN: /* ECN forbidden */
111 * limited-functionality: set not-ECT to the outer
113 *outer &= ~IPTOS_ECN_MASK;
115 case ECN_NOCARE: /* no consideration to ECN */
121 * modify inner ECN (TOS) field on egress operation (tunnel decapsulation).
122 * the caller should drop the packet if the return value is 0.
125 ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner)
128 if (!outer || !inner)
129 panic("NULL pointer passed to ip_ecn_egress");
134 * full-functionality: if the outer is CE and the inner is
135 * not-ECT, should drop it. otherwise, copy CE.
137 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) {
138 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
140 *inner |= IPTOS_ECN_CE;
143 case ECN_FORBIDDEN: /* ECN forbidden */
145 * limited-functionality: if the outer is CE, should drop it.
146 * otherwise, leave the inner.
148 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
151 case ECN_NOCARE: /* no consideration to ECN */
159 ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner)
161 u_int8_t outer8, inner8;
163 if (!outer || !inner)
164 panic("NULL pointer passed to ip6_ecn_ingress");
166 inner8 = (ntohl(*inner) >> 20) & 0xff;
167 ip_ecn_ingress(mode, &outer8, &inner8);
168 *outer &= ~htonl(0xff << 20);
169 *outer |= htonl((u_int32_t)outer8 << 20);
173 ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner)
175 u_int8_t outer8, inner8, oinner8;
177 if (!outer || !inner)
178 panic("NULL pointer passed to ip6_ecn_egress");
180 outer8 = (ntohl(*outer) >> 20) & 0xff;
181 inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff;
182 if (ip_ecn_egress(mode, &outer8, &inner8) == 0)
184 if (inner8 != oinner8) {
185 *inner &= ~htonl(0xff << 20);
186 *inner |= htonl((u_int32_t)inner8 << 20);