fmt_ip6ifc(3) [debian man page]

fmt_ip6ifc(3)						     Library Functions Manual						     fmt_ip6ifc(3)

NAME

       fmt_ip6ifc - write a formatted ASCII representation of an IPv6 number

SYNTAX

       #include <ip6.h>

       unsigned int fmt_ip6ifc(char *dest,const char ip[16],uint32 scope_id);

DESCRIPTION

       fmt_ip6ifc formats an IPv6 number in ASCII representation from ip and writes the result into dest. It returns the number of bytes written.

       fmt_ip6ifc will apply "::" compression to the output.

       If ip is an IPv4-mapped IPv6 address, fmt_ip6ifc will output it as IPv4 address.

       If dest equals FMT_LEN (i.e. is zero), fmt_ip6ifc returns the number of bytes it would have written.

       fmt_ip6 does not append .

       ip6.h  defines  the integer IP6_FMT to be big enough to contain every possible fmt_ip6 output plus .  However, for fmt_ip6ifc you need to
       add 1 for the '%' and IF_NAMESIZE from <net/if.h> for the interface name.

EXAMPLE

       #include <ip6.h>

	 char buf[IP6_FMT];
	 char ip[16];
	 scope_id sid;
	 buf[fmt_ip6ifc(buf,ip,sid)]=0;

SEE ALSO

       scan_ip6(3), fmt_ip4(3)

																     fmt_ip6ifc(3)

FAITH(4)						   BSD Kernel Interfaces Manual 						  FAITH(4)

NAME

     faith -- IPv6-to-IPv4 TCP relay capturing interface

SYNOPSIS

     device faith

DESCRIPTION

     The faith interface captures IPv6 TCP traffic, for implementing userland IPv6-to-IPv4 TCP relay like faithd(8).

     Each faith interface is created at runtime using interface cloning.  This is most easily done with the ifconfig(8) create command or using
     the cloned_interfaces variable in rc.conf(5).

     Special action will be taken when IPv6 TCP traffic is seen on a router, and the routing table suggests to route it to the faith interface.
     In this case, the packet will be accepted by the router, regardless of the list of IPv6 interface addresses assigned to the router.  The
     packet will be captured by an IPv6 TCP socket, if it has the IN6P_FAITH flag turned on and matching address/port pairs.  As a result, faith
     will let you capture IPv6 TCP traffic to some specific destination addresses.  Userland programs, such as faithd(8) can use this behavior to
     relay IPv6 TCP traffic to IPv4 TCP traffic.  The program can accept some specific IPv6 TCP traffic, perform getsockname(2) to get the IPv6
     destination address specified by the client, and perform application-specific address mapping to relay IPv6 TCP to IPv4 TCP.

     The IN6P_FAITH flag on a IPv6 TCP socket can be set by using setsockopt(2), with level IPPROTO_IPV6 and optname IPv6_FAITH.

     To handle error reports by ICMPv6, some ICMPv6 packets routed to an faith interface will be delivered to IPv6 TCP, as well.

     To understand how faith can be used, take a look at the source code of faithd(8).

     As the faith interface implements potentially dangerous operations, great care must be taken when configuring it.	To avoid possible misuse,
     the sysctl(8) variable net.inet6.ip6.keepfaith must be set to 1 prior to using the interface.  When net.inet6.ip6.keepfaith is 0, no packets
     will be captured by the faith interface.

     The faith interface is intended to be used on routers, not on hosts.

SEE ALSO

     inet(4), inet6(4), faithd(8)

     Jun-ichiro itojun Hagino and Kazu Yamamoto, An IPv6-to-IPv4 transport relay translator, RFC3142.

HISTORY

     The FAITH IPv6-to-IPv4 TCP relay translator first appeared in the WIDE hydrangea IPv6 stack.

BSD
								  April 10, 1999							       BSD