1/*	$NetBSD: ip_ecn.c,v 1.17 2017/12/09 08:03:07 pgoyette Exp $	*/
2/*	$KAME: ip_ecn.c,v 1.11 2001/05/03 16:09:29 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/cdefs.h>
39__KERNEL_RCSID(0, "$NetBSD: ip_ecn.c,v 1.17 2017/12/09 08:03:07 pgoyette Exp $");
40
41#ifdef _KERNEL_OPT
42#include "opt_inet.h"
43#endif
44
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/malloc.h>
48#include <sys/mbuf.h>
49#include <sys/errno.h>
50#include <sys/module.h>
51
52#include <netinet/in.h>
53#include <netinet/in_systm.h>
54#include <netinet/ip.h>
55#ifdef INET6
56#include <netinet/ip6.h>
57#endif
58
59#include <netinet/ip_ecn.h>
60
61/*
62 * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation).
63 */
64void
65ip_ecn_ingress(int mode, u_int8_t *outer, const u_int8_t *inner)
66{
67	if (!outer || !inner)
68		panic("NULL pointer passed to ip_ecn_ingress");
69
70	*outer = *inner;
71	switch (mode) {
72	case ECN_ALLOWED:		/* ECN allowed */
73		*outer &= ~IPTOS_ECN_CE;
74		break;
75	case ECN_FORBIDDEN:		/* ECN forbidden */
76		*outer &= ~(IPTOS_ECN_ECT0 | IPTOS_ECN_CE);
77		break;
78	case ECN_NOCARE:	/* no consideration to ECN */
79		break;
80	}
81}
82
83/*
84 * modify inner ECN (TOS) field on egress operation (tunnel decapsulation).
85 */
86void
87ip_ecn_egress(int mode, const u_int8_t *outer, u_int8_t *inner)
88{
89	if (!outer || !inner)
90		panic("NULL pointer passed to ip_ecn_egress");
91
92	switch (mode) {
93	case ECN_ALLOWED:
94		if (*outer & IPTOS_ECN_CE)
95			*inner |= IPTOS_ECN_CE;
96		break;
97	case ECN_FORBIDDEN:		/* ECN forbidden */
98	case ECN_NOCARE:	/* no consideration to ECN */
99		break;
100	}
101}
102
103#ifdef INET6
104void
105ip6_ecn_ingress(int mode, u_int32_t *outer, const u_int32_t *inner)
106{
107	u_int8_t outer8, inner8;
108
109	if (!outer || !inner)
110		panic("NULL pointer passed to ip6_ecn_ingress");
111
112	outer8 = (ntohl(*outer) >> 20) & 0xff;
113	inner8 = (ntohl(*inner) >> 20) & 0xff;
114	ip_ecn_ingress(mode, &outer8, &inner8);
115	*outer &= ~htonl(0xff << 20);
116	*outer |= htonl((u_int32_t)outer8 << 20);
117}
118
119void
120ip6_ecn_egress(int mode, const u_int32_t *outer, u_int32_t *inner)
121{
122	u_int8_t outer8, inner8;
123
124	if (!outer || !inner)
125		panic("NULL pointer passed to ip6_ecn_egress");
126
127	outer8 = (ntohl(*outer) >> 20) & 0xff;
128	inner8 = (ntohl(*inner) >> 20) & 0xff;
129	ip_ecn_egress(mode, &outer8, &inner8);
130	*inner &= ~htonl(0xff << 20);
131	*inner |= htonl((u_int32_t)inner8 << 20);
132}
133#endif
134
135MODULE(MODULE_CLASS_MISC, ip_ecn, NULL);
136
137static int
138ip_ecn_modcmd(modcmd_t cmd, void *arg)
139{
140
141	switch (cmd) {
142	case MODULE_CMD_INIT:
143	case MODULE_CMD_FINI:
144		return 0;
145
146	default:
147		return ENOTTY;
148        }
149}
150
151