FreeBSD/Linux Kernel Cross Reference
sys/modules/netgraph/ksocket/ng_ksocket.4

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    .\" Author: Archie Cobbs <archie@freebsd.org>
    .\"
    .\" $FreeBSD$
    .\"
    .Dd November 15, 1999
    .Dt NG_KSOCKET 4
    .Os FreeBSD
    .Sh NAME
    .Nm ng_ksocket
    .Nd kernel socket netgraph node type
    .Sh SYNOPSIS
    .Fd #include <netgraph/ng_ksocket.h>
    .Sh DESCRIPTION
    A
    .Nm ksocket
    node is both a netgraph node and a BSD 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
    .Dv Em <family>/<type>/<proto> ,
    where the
    .Dv Em family ,
    .Dv Em type ,
    and
    .Dv 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 .
    .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
    .Dv "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 paramter (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
   .Dv "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 getname 2
   system call.  The name is returned as a
   .Dv "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
   .Dv "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
   .Dv "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
   .Dv "struct ng_ksocket_sockopt" .
   When sending this command, the
   .Dv value
   field should be empty; upon return, it will contain the
   retrieved value.
   .El
   .Pp
   .Sh ASCII FORM CONTROL MESSAGES
   For control messages that pass a
   .Dv "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
   .Dv "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
   .Sh HISTORY
   The
   .Nm
   node type was implemented in
   .Fx 4.0 .
   .Sh AUTHORS
   .An Archie Cobbs Aq archie@freebsd.org

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