| /* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc Exp $ */ |
| |
| /*- |
| * Copyright (C) 1999 WIDE Project. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the project nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * |
| */ |
| /* |
| * ECN consideration on tunnel ingress/egress operation. |
| * http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt |
| */ |
| |
| #include <sys/bsd_cdefs.h> |
| //__FBSDID("$FreeBSD$"); |
| |
| #include "bsd_opt_inet.h" |
| #include "bsd_opt_inet6.h" |
| |
| #include <sys/bsd_param.h> |
| #include <sys/bsd_systm.h> |
| #include <sys/bsd_mbuf.h> |
| #include <sys/bsd_errno.h> |
| |
| #include <netinet/bsd_in.h> |
| #include <netinet/bsd_in_systm.h> |
| #include <netinet/bsd_ip.h> |
| #ifdef INET6 |
| #include <netinet/bsd_ip6.h> |
| #endif |
| |
| #include <netinet/bsd_ip_ecn.h> |
| #ifdef INET6 |
| #include <netinet6/bsd_ip6_ecn.h> |
| #endif |
| |
| /* |
| * ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and |
| * decapsulation from RFC3168: |
| * |
| * Outer Hdr at Inner Hdr at |
| * Encapsulator Decapsulator |
| * Header fields: -------------------- ------------ |
| * DS Field copied from inner hdr no change |
| * ECN Field constructed by (I) constructed by (E) |
| * |
| * ECN_ALLOWED (full functionality): |
| * (I) if the ECN field in the inner header is set to CE, then set the |
| * ECN field in the outer header to ECT(0). |
| * otherwise, copy the ECN field to the outer header. |
| * |
| * (E) if the ECN field in the outer header is set to CE and the ECN |
| * field of the inner header is not-ECT, drop the packet. |
| * if the ECN field in the inner header is set to ECT(0) or ECT(1) |
| * and the ECN field in the outer header is set to CE, then copy CE to |
| * the inner header. otherwise, make no change to the inner header. |
| * |
| * ECN_FORBIDDEN (limited functionality): |
| * (I) set the ECN field to not-ECT in the outer header. |
| * |
| * (E) if the ECN field in the outer header is set to CE, drop the packet. |
| * otherwise, make no change to the ECN field in the inner header. |
| * |
| * the drop rule is for backward compatibility and protection against |
| * erasure of CE. |
| */ |
| |
| /* |
| * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation). |
| */ |
| void |
| ip_ecn_ingress(int mode, u_int8_t *outer, const u_int8_t *inner) |
| { |
| |
| if (!outer || !inner) |
| panic("NULL pointer passed to ip_ecn_ingress"); |
| |
| *outer = *inner; |
| switch (mode) { |
| case ECN_ALLOWED: /* ECN allowed */ |
| /* |
| * full-functionality: if the inner is CE, set ECT(0) |
| * to the outer. otherwise, copy the ECN field. |
| */ |
| if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE) |
| *outer &= ~IPTOS_ECN_ECT1; |
| break; |
| case ECN_FORBIDDEN: /* ECN forbidden */ |
| /* |
| * limited-functionality: set not-ECT to the outer |
| */ |
| *outer &= ~IPTOS_ECN_MASK; |
| break; |
| case ECN_NOCARE: /* no consideration to ECN */ |
| break; |
| } |
| } |
| |
| /* |
| * modify inner ECN (TOS) field on egress operation (tunnel decapsulation). |
| * the caller should drop the packet if the return value is 0. |
| */ |
| int |
| ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner) |
| { |
| |
| if (!outer || !inner) |
| panic("NULL pointer passed to ip_ecn_egress"); |
| |
| switch (mode) { |
| case ECN_ALLOWED: |
| /* |
| * full-functionality: if the outer is CE and the inner is |
| * not-ECT, should drop it. otherwise, copy CE. |
| */ |
| if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) { |
| if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT) |
| return (0); |
| *inner |= IPTOS_ECN_CE; |
| } |
| break; |
| case ECN_FORBIDDEN: /* ECN forbidden */ |
| /* |
| * limited-functionality: if the outer is CE, should drop it. |
| * otherwise, leave the inner. |
| */ |
| if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) |
| return (0); |
| break; |
| case ECN_NOCARE: /* no consideration to ECN */ |
| break; |
| } |
| return (1); |
| } |
| |
| #ifdef INET6 |
| void |
| ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner) |
| { |
| u_int8_t outer8, inner8; |
| |
| if (!outer || !inner) |
| panic("NULL pointer passed to ip6_ecn_ingress"); |
| |
| inner8 = (ntohl(*inner) >> 20) & 0xff; |
| ip_ecn_ingress(mode, &outer8, &inner8); |
| *outer &= ~htonl(0xff << 20); |
| *outer |= htonl((u_int32_t)outer8 << 20); |
| } |
| |
| int |
| ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner) |
| { |
| u_int8_t outer8, inner8, oinner8; |
| |
| if (!outer || !inner) |
| panic("NULL pointer passed to ip6_ecn_egress"); |
| |
| outer8 = (ntohl(*outer) >> 20) & 0xff; |
| inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff; |
| if (ip_ecn_egress(mode, &outer8, &inner8) == 0) |
| return (0); |
| if (inner8 != oinner8) { |
| *inner &= ~htonl(0xff << 20); |
| *inner |= htonl((u_int32_t)inner8 << 20); |
| } |
| return (1); |
| } |
| #endif |