243 lines
7.4 KiB
Groff
243 lines
7.4 KiB
Groff
.\" Copyright (c) 1999 Whistle Communications, Inc.
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.\" All rights reserved.
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.\"
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.\" Subject to the following obligations and disclaimer of warranty, use and
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.\" redistribution of this software, in source or object code forms, with or
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.\" without modifications are expressly permitted by Whistle Communications;
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.\" provided, however, that:
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.\" 1. Any and all reproductions of the source or object code must include the
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.\" copyright notice above and the following disclaimer of warranties; and
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.\" 2. No rights are granted, in any manner or form, to use Whistle
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.\" Communications, Inc. trademarks, including the mark "WHISTLE
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.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as
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.\" such appears in the above copyright notice or in the software.
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.\"
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.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
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.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
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.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
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.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
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.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
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.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
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.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
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.\" OF SUCH DAMAGE.
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.\"
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.\" Author: Archie Cobbs <archie@FreeBSD.org>
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.\"
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.\" $FreeBSD$
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.\"
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.Dd January 9, 2012
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.Dt NG_KSOCKET 4
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.Os
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.Sh NAME
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.Nm ng_ksocket
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.Nd kernel socket netgraph node type
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.Sh SYNOPSIS
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.In sys/types.h
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.In netgraph/ng_ksocket.h
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.Sh DESCRIPTION
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A
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.Nm ksocket
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node is both a netgraph node and a
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.Bx
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socket.
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The
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.Nm
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node type allows one to open a socket inside the kernel and have
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it appear as a Netgraph node.
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The
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.Nm
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node type is the reverse of the socket node type (see
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.Xr ng_socket 4 ) :
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whereas the socket node type enables the user-level manipulation (via
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a socket) of what is normally a kernel-level entity (the associated
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Netgraph node), the
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.Nm
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node type enables the kernel-level manipulation (via a Netgraph node) of
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what is normally a user-level entity (the associated socket).
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.Pp
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A
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.Nm
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node allows at most one hook connection.
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Connecting to the node is
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equivalent to opening the associated socket.
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The name given to the hook
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determines what kind of socket the node will open (see below).
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When the hook is disconnected and/or the node is shutdown, the
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associated socket is closed.
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.Sh HOOKS
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This node type supports a single hook connection at a time.
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The name of the hook must be of the form
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.Em <family>/<type>/<proto> ,
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where the
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.Em family ,
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.Em type ,
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and
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.Em proto
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are the decimal equivalent of the same arguments to
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.Xr socket 2 .
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Alternately, aliases for the commonly used values are accepted as
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well.
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For example
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.Dv inet/dgram/udp
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is a more readable but equivalent version of
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.Dv 2/2/17 .
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.Pp
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Data received into socket is sent out via hook.
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Data received on hook is sent out from socket, if the latter is
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connected (an
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.Dv NGM_KSOCKET_CONNECT
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was sent to node before).
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If socket is not connected, destination
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.Vt "struct sockaddr"
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must be supplied in an mbuf tag with cookie
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.Dv NGM_KSOCKET_COOKIE
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and type
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.Dv NG_KSOCKET_TAG_SOCKADDR
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attached to data.
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Otherwise
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.Nm
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will return
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.Er ENOTCONN
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to sender.
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.Sh CONTROL MESSAGES
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This node type supports the generic control messages, plus the following:
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.Bl -tag -width foo
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.It Dv NGM_KSOCKET_BIND Pq Ic bind
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This functions exactly like the
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.Xr bind 2
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system call.
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The
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.Vt "struct sockaddr"
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socket address parameter should be supplied as an argument.
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.It Dv NGM_KSOCKET_LISTEN Pq Ic listen
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This functions exactly like the
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.Xr listen 2
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system call.
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The backlog parameter (a single 32 bit
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.Dv int )
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should be supplied as an argument.
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.It Dv NGM_KSOCKET_CONNECT Pq Ic connect
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This functions exactly like the
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.Xr connect 2
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system call.
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The
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.Vt "struct sockaddr"
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destination address parameter should be supplied as an argument.
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.It Dv NGM_KSOCKET_ACCEPT Pq Ic accept
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Equivalent to the
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.Xr accept 2
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system call on a non-blocking socket.
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If there is a pending connection on the queue,
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a new socket and a corresponding cloned node are created.
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Returned are the cloned node's ID and a peer name (as
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.Vt "struct sockaddr" ) .
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If there are no pending connections,
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this control message returns nothing,
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and a connected node will receive the above message asynchronously,
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when a connection is established.
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.Pp
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A cloned node supports a single hook with an arbitrary name.
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If not connected, a node disappears when its parent node is destroyed.
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Once connected, it becomes an independent node.
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.It Dv NGM_KSOCKET_GETNAME Pq Ic getname
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Equivalent to the
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.Xr getsockname 2
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system call.
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The name is returned as a
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.Vt "struct sockaddr"
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in the arguments field of the reply.
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.It Dv NGM_KSOCKET_GETPEERNAME Pq Ic getpeername
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Equivalent to the
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.Xr getpeername 2
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system call.
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The name is returned as a
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.Vt "struct sockaddr"
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in the arguments field of the reply.
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.It Dv NGM_KSOCKET_SETOPT Pq Ic setopt
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Equivalent to the
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.Xr setsockopt 2
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system call, except that the option name, level, and value are passed in a
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.Vt "struct ng_ksocket_sockopt" .
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.It Dv NGM_KSOCKET_GETOPT Pq Ic getopt
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Equivalent to the
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.Xr getsockopt 2
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system call, except that the option is passed in a
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.Vt "struct ng_ksocket_sockopt" .
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When sending this command, the
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.Dv value
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field should be empty; upon return, it will contain the
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retrieved value.
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.El
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.Sh ASCII FORM CONTROL MESSAGES
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For control messages that pass a
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.Vt "struct sockaddr"
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in the argument field, the normal
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.Tn ASCII
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equivalent of the C structure
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is an acceptable form.
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For the
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.Dv PF_INET
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and
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.Dv PF_LOCAL
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address families, a more convenient form is also used, which is
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the protocol family name, followed by a slash, followed by the actual
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address.
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For
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.Dv PF_INET ,
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the address is an IP address followed by an optional colon and port number.
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For
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.Dv PF_LOCAL ,
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the address is the pathname as a doubly quoted string.
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.Pp
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Examples:
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.Bl -tag -width "PF_LOCAL"
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.It Dv PF_LOCAL
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local/"/tmp/foo.socket"
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.It Dv PF_INET
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inet/192.168.1.1:1234
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.It Other
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.Dv "\&{ family=16 len=16 data=[0x70 0x00 0x01 0x23] \&}"
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.El
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.Pp
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For control messages that pass a
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.Vt "struct ng_ksocket_sockopt" ,
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the normal
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.Tn ASCII
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form for that structure is used.
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In the future, more
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convenient encoding of the more common socket options may be supported.
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.Pp
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Setting socket options example:
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.Bl -tag -width "PF_LOCAL"
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.It Set FIB 2 for a socket (SOL_SOCKET, SO_SETFIB):
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.Dv "setopt \&{ level=0xffff name=0x1014 data=[ 2 ] \&}"
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of a
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.Dv NGM_SHUTDOWN
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control message, or when the hook is disconnected.
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Shutdown of the node closes the associated socket.
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.Sh SEE ALSO
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.Xr socket 2 ,
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.Xr netgraph 4 ,
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.Xr ng_socket 4 ,
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.Xr ngctl 8 ,
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.Xr mbuf_tags 9 ,
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.Xr socket 9
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.Sh HISTORY
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The
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.Nm
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node type was implemented in
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.Fx 4.0 .
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.Sh AUTHORS
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.An Archie Cobbs Aq Mt archie@FreeBSD.org
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