Annotation of sys/netinet/ip_ecn.c, Revision 1.1
1.1 ! nbrk 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
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