.\" Copyright (c) 1999 Whistle Communications, Inc.
.\" All rights reserved.
.\"
.\" Subject to the following obligations and disclaimer of warranty, use and
.\" redistribution of this software, in source or object code forms, with or
.\" without modifications are expressly permitted by Whistle Communications;
.\" provided, however, that:
.\" 1. Any and all reproductions of the source or object code must include the
.\"    copyright notice above and the following disclaimer of warranties; and
.\" 2. No rights are granted, in any manner or form, to use Whistle
.\"    Communications, Inc. trademarks, including the mark "WHISTLE
.\"    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
.\"    such appears in the above copyright notice or in the software.
.\"
.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
.\" OF SUCH DAMAGE.
.\"
.\" Author: Archie Cobbs <archie@FreeBSD.org>
.\"
.\" $FreeBSD: src/share/man/man4/ng_ksocket.4,v 1.20 2005/02/05 11:31:31 ru Exp $
.\"
.Dd June 8, 2004
.Dt NG_KSOCKET 4
.Os
.Sh NAME
.Nm ng_ksocket
.Nd kernel socket netgraph node type
.Sh SYNOPSIS
.In sys/types.h
.In netgraph/ng_ksocket.h
.Sh DESCRIPTION
A
.Nm ksocket
node is both a netgraph node and a
.Bx
socket.
The
.Nm
node type allows one to open a socket inside the kernel and have
it appear as a Netgraph node.
The
.Nm
node type is the reverse of the socket node type (see
.Xr ng_socket 4 ) :
whereas the socket node type enables the user-level manipulation (via
a socket) of what is normally a kernel-level entity (the associated
Netgraph node), the
.Nm
node type enables the kernel-level manipulation (via a Netgraph node) of
what is normally a user-level entity (the associated socket).
.Pp
A
.Nm
node allows at most one hook connection.
Connecting to the node is
equivalent to opening the associated socket.
The name given to the hook
determines what kind of socket the node will open (see below).
When the hook is disconnected and/or the node is shutdown, the
associated socket is closed.
.Sh HOOKS
This node type supports a single hook connection at a time.
The name of the hook must be of the form
.Em <family>/<type>/<proto> ,
where the
.Em family ,
.Em type ,
and
.Em proto
are the decimal equivalent of the same arguments to
.Xr socket 2 .
Alternately, aliases for the commonly used values are accepted as
well.
For example
.Dv inet/dgram/udp
is a more readable but equivalent version of
.Dv 2/2/17 .
.Pp
Data received into socket is sent out via hook.
Data received on hook is sent out from socket, if the latter is
connected (an
.Dv NGM_KSOCKET_CONNECT
was sent to node before).
If socket is not connected, destination
.Vt "struct sockaddr"
must be supplied in an mbuf tag with cookie
.Dv NGM_KSOCKET_COOKIE
and type
.Dv NG_KSOCKET_TAG_SOCKADDR
attached to data.
Otherwise
.Nm
will return
.Er ENOTCONN
to sender.
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_KSOCKET_BIND
This functions exactly like the
.Xr bind 2
system call.
The
.Vt "struct sockaddr"
socket address parameter should be supplied as an argument.
.It Dv NGM_KSOCKET_LISTEN
This functions exactly like the
.Xr listen 2
system call.
The backlog parameter (a single 32 bit
.Dv int )
should be supplied as an argument.
.It Dv NGM_KSOCKET_CONNECT
This functions exactly like the
.Xr connect 2
system call.
The
.Vt "struct sockaddr"
destination address parameter should be supplied as an argument.
.It Dv NGM_KSOCKET_ACCEPT
Currently unimplemented.
.It Dv NGM_KSOCKET_GETNAME
Equivalent to the
.Xr getsockname 2
system call.
The name is returned as a
.Vt "struct sockaddr"
in the arguments field of the reply.
.It Dv NGM_KSOCKET_GETPEERNAME
Equivalent to the
.Xr getpeername 2
system call.
The name is returned as a
.Vt "struct sockaddr"
in the arguments field of the reply.
.It Dv NGM_KSOCKET_SETOPT
Equivalent to the
.Xr setsockopt 2
system call, except that the option name, level, and value are passed in a
.Vt "struct ng_ksocket_sockopt" .
.It Dv NGM_KSOCKET_GETOPT
Equivalent to the
.Xr getsockopt 2
system call, except that the option is passed in a
.Vt "struct ng_ksocket_sockopt" .
When sending this command, the
.Dv value
field should be empty; upon return, it will contain the
retrieved value.
.El
.Sh ASCII FORM CONTROL MESSAGES
For control messages that pass a
.Vt "struct sockaddr"
in the argument field, the normal
.Tn ASCII
equivalent of the C structure
is an acceptable form.
For the
.Dv PF_INET
and
.Dv PF_LOCAL
address families, a more convenient form is also used, which is
the protocol family name, followed by a slash, followed by the actual
address.
For
.Dv PF_INET ,
the address is an IP address followed by an optional colon and port number.
For
.Dv PF_LOCAL ,
the address is the pathname as a doubly quoted string.
.Pp
Examples:
.Bl -tag -width XXXXXXXXXX
.It Dv PF_LOCAL
local/"/tmp/foo.socket"
.It Dv PF_INET
inet/192.168.1.1:1234
.It Other
.Dv "\&{ family=16 len=16 data=[0x70 0x00 0x01 0x23] \&}"
.El
.Pp
For control messages that pass a
.Vt "struct ng_ksocket_sockopt" ,
the normal
.Tn ASCII
form for that structure is used.
In the future, more
convenient encoding of the more common socket options may be supported.
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, or when the hook is disconnected.
Shutdown of the node closes the associated socket.
.Sh SEE ALSO
.Xr socket 2 ,
.Xr netgraph 4 ,
.Xr ng_socket 4 ,
.Xr ngctl 8 ,
.Xr mbuf_tags 9
.Sh HISTORY
The
.Nm
node type was implemented in
.Fx 4.0 .
.Sh AUTHORS
.An Archie Cobbs Aq archie@FreeBSD.org