FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_ecn.c
1 /* $FreeBSD: releng/5.3/sys/netinet/ip_ecn.c 136588 2004-10-16 08:43:07Z cvs2svn $ */
2 /* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc 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 "opt_inet.h"
39 #include "opt_inet6.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/mbuf.h>
44 #include <sys/errno.h>
45
46 #include <netinet/in.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/ip.h>
49 #ifdef INET6
50 #include <netinet/ip6.h>
51 #endif
52
53 #include <netinet/ip_ecn.h>
54 #ifdef INET6
55 #include <netinet6/ip6_ecn.h>
56 #endif
57
58 /*
59 * ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and
60 * decapsulation from RFC3168:
61 *
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)
67 *
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.
72 *
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.
78 *
79 * ECN_FORBIDDEN (limited functionality):
80 * (I) set the ECN field to not-ECT in the outer header.
81 *
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.
84 *
85 * the drop rule is for backward compatibility and protection against
86 * erasure of CE.
87 */
88
89 /*
90 * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
91 */
92 void
93 ip_ecn_ingress(mode, outer, inner)
94 int mode;
95 u_int8_t *outer;
96 const 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 * the caller should drop the packet if the return value is 0.
125 */
126 int
127 ip_ecn_egress(mode, outer, inner)
128 int mode;
129 const u_int8_t *outer;
130 u_int8_t *inner;
131 {
132 if (!outer || !inner)
133 panic("NULL pointer passed to ip_ecn_egress");
134
135 switch (mode) {
136 case ECN_ALLOWED:
137 /*
138 * full-functionality: if the outer is CE and the inner is
139 * not-ECT, should drop it. otherwise, copy CE.
140 */
141 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) {
142 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
143 return (0);
144 *inner |= IPTOS_ECN_CE;
145 }
146 break;
147 case ECN_FORBIDDEN: /* ECN forbidden */
148 /*
149 * limited-functionality: if the outer is CE, should drop it.
150 * otherwise, leave the inner.
151 */
152 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
153 return (0);
154 break;
155 case ECN_NOCARE: /* no consideration to ECN */
156 break;
157 }
158 return (1);
159 }
160
161 #ifdef INET6
162 void
163 ip6_ecn_ingress(mode, outer, inner)
164 int mode;
165 u_int32_t *outer;
166 const u_int32_t *inner;
167 {
168 u_int8_t outer8, inner8;
169
170 if (!outer || !inner)
171 panic("NULL pointer passed to ip6_ecn_ingress");
172
173 inner8 = (ntohl(*inner) >> 20) & 0xff;
174 ip_ecn_ingress(mode, &outer8, &inner8);
175 *outer &= ~htonl(0xff << 20);
176 *outer |= htonl((u_int32_t)outer8 << 20);
177 }
178
179 int
180 ip6_ecn_egress(mode, outer, inner)
181 int mode;
182 const u_int32_t *outer;
183 u_int32_t *inner;
184 {
185 u_int8_t outer8, inner8, oinner8;
186
187 if (!outer || !inner)
188 panic("NULL pointer passed to ip6_ecn_egress");
189
190 outer8 = (ntohl(*outer) >> 20) & 0xff;
191 inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff;
192 if (ip_ecn_egress(mode, &outer8, &inner8) == 0)
193 return (0);
194 if (inner8 != oinner8) {
195 *inner &= ~htonl(0xff << 20);
196 *inner |= htonl((u_int32_t)inner8 << 20);
197 }
198 return (1);
199 }
200 #endif
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