.\" $OpenBSD: icmp6.4,v 1.16 2003/10/22 20:12:25 jmc Exp $ .\" $KAME: icmp6.4,v 1.3 2000/11/24 08:44:40 itojun 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. 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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 University 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 REGENTS 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 REGENTS 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. .\" .Dd December 17, 1999 .Dt ICMP6 4 .Os .Sh NAME .Nm icmp6 .Nd Internet Control Message Protocol for IPv6 .Sh SYNOPSIS .Fd #include .Fd #include .Fd #include .Ft int .Fn socket AF_INET6 SOCK_RAW proto .Sh DESCRIPTION .Tn ICMPv6 is the error and control message protocol used by .Tn IPv6 and the Internet protocol family. It may be accessed through a .Dq raw socket for network monitoring and diagnostic functions. The .Fa proto parameter to the socket call to create an .Tn ICMPv6 socket is obtained from .Xr getprotobyname 3 , or you can use .Dv IPPROTO_ICMPV6 . .Tn ICMPv6 sockets are connectionless, and are normally used with the .Xr sendto 2 and .Xr recvfrom 2 calls, though the .Xr connect 2 call may also be used to fix the destination for future packets (in which case the .Xr read 2 or .Xr recv 2 and .Xr write 2 or .Xr send 2 system calls may be used). .Pp Outgoing packets automatically have an .Tn IPv6 header prepended to them .Pq based on the destination address . The .Tn ICMPv6 pseudo-header checksum field .Pq Li icmp6_cksum is filled automatically by the kernel. Incoming packets are received without the .Tn IPv6 header or IPv6 extension headers. Notice that this behavior is opposite to that of .Tn IPv4 raw sockets and .Tn ICMPv4 sockets. .Ss ICMPv6 type/code filter Each .Tn ICMPv6 raw socket has an associated filter whose datatype is defined as .Li struct icmp6_filter ; .Pp This structure, along with the macros and constants defined later in this section, are defined as a result of including the .Aq Li netinet/icmp6.h header. .Pp The current filter is fetched and stored using .Xr getsockopt 2 and .Xr setsockopt 2 with a level of .Dv IPPROTO_ICMPV6 and an option name of .Dv ICMP6_FILTER . .Pp Six macros operate on an icmp6_filter structure: .\" is "Fn" legal for macros? .Pp .Bl -item -compact -offset indent .It .Ft void .Fn ICMP6_FILTER_SETPASSALL "struct icmp6_filter *" .It .Ft void .Fn ICMP6_FILTER_SETBLOCKALL "struct icmp6_filter *" .It .Ft void .Fn ICMP6_FILTER_SETPASS "int" "struct icmp6_filter *" .It .Ft void .Fn ICMP6_FILTER_SETBLOCK "int" "struct icmp6_filter *" .It .Ft int .Fn ICMP6_FILTER_WILLPASS "int" "const struct icmp6_filter *" .It .Ft int .Fn ICMP6_FILTER_WILLBLOCK "int" "const struct icmp6_filter *" .El .Pp The first argument to the last four macros .Pq an integer is an .Tn ICMPv6 message type, between 0 and 255. The pointer argument to all six macros is a pointer to a filter that is modified by the first four macros examined by the last two macros. .Pp The first two macros, .Dv SETPASSALL and .Dv SETBLOCKALL , specify that all .Tn ICMPv6 messages are passed to the application or that all .Tn ICMPv6 messages are blocked from being passed to the application. .Pp The next two macros, .Dv SETPASS and .Dv SETBLOCK , specify that messages of a given .Tn ICMPv6 type should be passed to the application or not passed to the application .Pq blocked . .Pp The final two macros, .Dv WILLPASS and .Dv WILLBLOCK , return true or false depending on whether the specified message type is passed to the application or blocked from being passed to the application by the filter pointed to by the second argument. .Pp When an .Tn ICMPv6 raw socket is created, it will by default pass all .Tn ICMPv6 message types to the application. .Pp For further discussions see RFC 2292. .Sh DIAGNOSTICS A socket operation may fail with one of the following errors returned: .Bl -tag -width [EADDRNOTAVAIL] .It Bq Er EISCONN when trying to establish a connection on a socket which already has one, or when trying to send a datagram with the destination address specified and the socket is already connected. .It Bq Er ENOTCONN when trying to send a datagram, but no destination address is specified, and the socket hasn't been connected. .It Bq Er ENOBUFS when the system runs out of memory for an internal data structure. .It Bq Er EADDRNOTAVAIL when an attempt is made to create a socket with a network address for which no network interface exists. .El .Sh SEE ALSO .Xr recv 2 , .Xr send 2 , .Xr inet6 4 , .Xr ip6 4 , .Xr netintro 4 .Rs .%A W. Stevens .%A M. Thomas .%R RFC 2292 .%D February 1998 .%T "Advanced Sockets API for IPv6" .Re .Rs .%A A. Conta .%A S. Deering .%R RFC 2463 .%D December 1998 .%T "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification" .Re .Sh HISTORY The implementation is based on KAME stack .Po which is a descendant of WIDE hydrangea IPv6 stack kit .Pc . .Pp Part of the document was shamelessly copied from RFC 2292.