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(int mode, u_int8_t *outer, const u_int8_t *inner) 94 { 95 96 if (!outer || !inner) 97 panic("NULL pointer passed to ip_ecn_ingress"); 98 99 *outer = *inner; 100 switch (mode) { 101 case ECN_ALLOWED: /* ECN allowed */ 102 /* 103 * full-functionality: if the inner is CE, set ECT(0) 104 * to the outer. otherwise, copy the ECN field. 105 */ 106 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE) 107 *outer &= ~IPTOS_ECN_ECT1; 108 break; 109 case ECN_FORBIDDEN: /* ECN forbidden */ 110 /* 111 * limited-functionality: set not-ECT to the outer 112 */ 113 *outer &= ~IPTOS_ECN_MASK; 114 break; 115 case ECN_NOCARE: /* no consideration to ECN */ 116 break; 117 } 118 } 119 120 /* 121 * modify inner ECN (TOS) field on egress operation (tunnel decapsulation). 122 * the caller should drop the packet if the return value is 0. 123 */ 124 int 125 ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner) 126 { 127 128 if (!outer || !inner) 129 panic("NULL pointer passed to ip_ecn_egress"); 130 131 switch (mode) { 132 case ECN_ALLOWED: 133 /* 134 * full-functionality: if the outer is CE and the inner is 135 * not-ECT, should drop it. otherwise, copy CE. 136 */ 137 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) { 138 if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT) 139 return (0); 140 *inner |= IPTOS_ECN_CE; 141 } 142 break; 143 case ECN_FORBIDDEN: /* ECN forbidden */ 144 /* 145 * limited-functionality: if the outer is CE, should drop it. 146 * otherwise, leave the inner. 147 */ 148 if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) 149 return (0); 150 break; 151 case ECN_NOCARE: /* no consideration to ECN */ 152 break; 153 } 154 return (1); 155 } 156 157 #ifdef INET6 158 void 159 ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner) 160 { 161 u_int8_t outer8, inner8; 162 163 if (!outer || !inner) 164 panic("NULL pointer passed to ip6_ecn_ingress"); 165 166 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); 170 } 171 172 int 173 ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner) 174 { 175 u_int8_t outer8, inner8, oinner8; 176 177 if (!outer || !inner) 178 panic("NULL pointer passed to ip6_ecn_egress"); 179 180 outer8 = (ntohl(*outer) >> 20) & 0xff; 181 inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff; 182 if (ip_ecn_egress(mode, &outer8, &inner8) == 0) 183 return (0); 184 if (inner8 != oinner8) { 185 *inner &= ~htonl(0xff << 20); 186 *inner |= htonl((u_int32_t)inner8 << 20); 187 } 188 return (1); 189 } 190 #endif 191