1 /* $OpenBSD: ip_ecn.c,v 1.4 2002/05/16 14:10:51 kjc Exp $ */
2 /* $KAME: ip_ecn.c,v 1.9 2000/10/01 12:44:48 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1999 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
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
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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
30 * SUCH DAMAGE.
31 *
32 */
33 /*
34 * ECN consideration on tunnel ingress/egress operation.
35 * http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt
36 */
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41
42 #ifdef INET
43 #include <netinet/in.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/ip.h>
46 #endif
47
48 #ifdef INET6
49 #ifndef INET
50 #include <netinet/in.h>
51 #endif
52 #include <netinet/ip6.h>
53 #endif
54
55 #include <netinet/ip_ecn.h>
56
57 /*
58 * ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and
59 * decapsulation from RFC3168:
60 *
61 * Outer Hdr at Inner Hdr at
62 * Encapsulator Decapsulator
63 * Header fields: -------------------- ------------
64 * DS Field copied from inner hdr no change
65 * ECN Field constructed by (I) constructed by (E)
66 *
67 * ECN_ALLOWED (full functionality):
68 * (I) if the ECN field in the inner header is set to CE, then set the
69 * ECN field in the outer header to ECT(0).
70 * otherwise, copy the ECN field to the outer header.
71 *
72 * (E) if the ECN field in the outer header is set to CE and the ECN
73 * field of the inner header is not-ECT, drop the packet.
74 * if the ECN field in the inner header is set to ECT(0) or ECT(1)
75 * and the ECN field in the outer header is set to CE, then copy CE to
76 * the inner header. otherwise, make no change to the inner header.
77 *
78 * ECN_FORBIDDEN (limited functionality):
79 * (I) set the ECN field to not-ECT in the outer header.
80 *
81 * (E) if the ECN field in the outer header is set to CE, drop the packet.
82 * otherwise, make no change to the ECN field in the inner header.
83 *
84 * the drop rule is for backward compatibility and protection against
85 * erasure of CE.
86 */
87
88 /*
89 * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
90 * call it after you've done the default initialization/copy for the outer.
91 */
92 void
93 ip_ecn_ingress(mode, outer, inner)
94 int mode;
95 u_int8_t *outer;
96 u_int8_t *inner;
97 {
98 if (!outer || !inner)
99 panic("NULL pointer passed to ip_ecn_ingress");
100
101 *outer = *inner;
102 switch (mode) {
103 case ECN_ALLOWED: /* ECN allowed */
104 /*
105 * full-functionality: if the inner is CE, set ECT(0)
106 * to the outer. otherwise, copy the ECN field.
107 */
108 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
109 *outer &= ~IPTOS_ECN_ECT1;
110 break;
111 case ECN_FORBIDDEN: /* ECN forbidden */
112 /*
113 * limited-functionality: set not-ECT to the outer
114 */
115 *outer &= ~IPTOS_ECN_MASK;
116 break;
117 case ECN_NOCARE: /* no consideration to ECN */
118 break;
119 }
120 }
121
122 /*
123 * modify inner ECN (TOS) field on egress operation (tunnel decapsulation).
124 * call it after you've done the default initialization/copy for the inner.
125 * the caller should drop the packet if the return value is 0.
126 */
127 int
128 ip_ecn_egress(mode, outer, inner)
129 int mode;
130 u_int8_t *outer;
131 u_int8_t *inner;
132 {
133 if (!outer || !inner)
134 panic("NULL pointer passed to ip_ecn_egress");
135
136 switch (mode) {
137 case ECN_ALLOWED:
138 /*
139 * full-functionality: if the outer is CE and the inner is
140 * not-ECT, should drop it. otherwise, copy CE.
141 */
142 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) {
143 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
144 return (0);
145 *inner |= IPTOS_ECN_CE;
146 }
147 break;
148 case ECN_FORBIDDEN: /* ECN forbidden */
149 /*
150 * limited-functionality: if the outer is CE, should drop it.
151 * otherwise, leave the inner.
152 */
153 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
154 return (0);
155 break;
156 case ECN_NOCARE: /* no consideration to ECN */
157 break;
158 }
159 return (1);
160 }
161
162 #ifdef INET6
163 void
164 ip6_ecn_ingress(mode, outer, inner)
165 int mode;
166 u_int32_t *outer;
167 u_int32_t *inner;
168 {
169 u_int8_t outer8, inner8;
170
171 if (!outer || !inner)
172 panic("NULL pointer passed to ip6_ecn_ingress");
173
174 inner8 = (ntohl(*inner) >> 20) & 0xff;
175 ip_ecn_ingress(mode, &outer8, &inner8);
176 *outer &= ~htonl(0xff << 20);
177 *outer |= htonl((u_int32_t)outer8 << 20);
178 }
179
180 int
181 ip6_ecn_egress(mode, outer, inner)
182 int mode;
183 u_int32_t *outer;
184 u_int32_t *inner;
185 {
186 u_int8_t outer8, inner8, oinner8;
187
188 if (!outer || !inner)
189 panic("NULL pointer passed to ip6_ecn_egress");
190
191 outer8 = (ntohl(*outer) >> 20) & 0xff;
192 inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff;
193 if (ip_ecn_egress(mode, &outer8, &inner8) == 0)
194 return (0);
195 if (inner8 != oinner8) {
196 *inner &= ~htonl(0xff << 20);
197 *inner |= htonl((u_int32_t)inner8 << 20);
198 }
199 return (1);
200 }
201 #endif