1 /* $FreeBSD$ */ 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 201