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      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  */
     64 void
     65 ip_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  */
     86 void
     87 ip_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
    104 void
    105 ip6_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 
    119 void
    120 ip6_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 
    135 MODULE(MODULE_CLASS_MISC, ip_ecn, NULL);
    136 
    137 static int
    138 ip_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