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 202