1.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 2.\" All rights reserved.
|
3.\"
|
3.\" |
4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the project nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission.
|
15.\"
|
15.\" |
16.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $Id: faith.4,v 1.1.1.1 1999/08/08 23:30:37 itojun Exp $
|
29.\" $FreeBSD: head/share/man/man4/faith.4 75670 2001-04-18 15:54:10Z ru $
|
29.\" $FreeBSD: head/share/man/man4/faith.4 76175 2001-05-01 09:15:30Z schweikh $ |
30.\" 31.Dd April 10, 1999 32.Dt FAITH 4 33.Os 34.Sh NAME 35.Nm faith 36.Nd 37.Tn IPv6-to-IPv4 TCP 38relay capturing interface 39.Sh SYNOPSIS
|
40.Cd "pseudo-device faith 1"
|
40.Cd "device faith 1" |
41.Sh DESCRIPTION 42The 43.Nm 44interface captures IPv6 TCP traffic 45for implementing userland IPv6-to-IPv4 TCP relays 46like 47.Xr faithd 8 . 48.Pp 49Special action will be taken when IPv6 TCP traffic is seen on a router 50and the routing table suggests to route it to the 51.Nm 52interface. 53In this case the packet will be accepted by the router, 54regardless of the list of IPv6 interface addresses assigned to the router. 55The packet will be captured by an IPv6 TCP socket if it has the 56.Dv IN6P_FAITH 57flag turned on and it has matching address/port pairs. 58As a result, 59.Nm 60will let you divert IPv6 TCP traffic to some specific destination addresses. 61Userland programs, such as 62.Xr faithd 8 , 63can use this behavior to relay IPv6 TCP traffic to IPv4 TCP traffic. 64The program can accept some specific IPv6 TCP traffic, perform 65.Xr getsockname 2 66to get the IPv6 destination address specified by the client, 67and perform application-specific address mapping to relay IPv6 TCP to IPv4 TCP. 68.Pp 69The 70.Dv IN6P_FAITH 71flag on an IPv6 TCP socket can be set by using 72.Xr setsockopt 2 , 73with 74.Fa level 75set to 76.Dv IPPROTO_IPV6 77and 78.Fa optname 79set to 80.Dv IPv6_FAITH . 81.Pp 82To handle error reports by ICMPv6 some of the ICMPv6 packets routed to the 83.Nm 84interface will need be delivered to IPv6 TCP as well. 85.Pp 86To understand how 87.Nm 88can be used take a look at the source code of 89.Xr faithd 8 . 90.Pp 91As the 92.Nm 93interface implements potentially dangerous operations, 94great care must be taken when configuring the 95.Nm 96interface. 97To avoid possible misuse the 98.Xr sysctl 8 99variable 100.Li net.inet6.ip6.keepfaith 101must be set to 102.Li 1 103prior to the use of the interface. 104When 105.Li net.inet6.ip6.keepfaith 106is set to 107.Li 0 , 108no packets will be captured by the 109.Nm 110interface. 111.Pp 112The 113.Nm 114interface is intended to be used on routers, not on hosts. 115.\" 116.Sh SEE ALSO 117.Xr inet 4 , 118.Xr inet6 4 , 119.Xr faithd 8 120.\" .Rs 121.\" .%A Jun-ichiro itojun Hagino 122.\" .%A Kazu Yamamoto 123.\" .%T ``FAITH'' IPv6-to-IPv4 TCP relay translator 124.\" .%D July 1999 125.\" .Re 126.\" 127.Sh HISTORY 128The FAITH IPv6-to-IPv4 TCP relay translator first appeared in 129WIDE hydrangea IPv6 stack.
|