f8307e1233
NGM_BINARY2ASCII, which convert control messages to ASCII and back. This allows control messages to be sent and received in ASCII form using ngctl(8), which makes ngctl a lot more useful. This also allows all the type-specific debugging code in libnetgraph to go away -- instead, we just ask the node itself to do the ASCII translation for us. Currently, all generic control messages are supported, as well as messages associated with the following node types: async, cisco, ksocket, and ppp. See /usr/share/examples/netgraph/ngctl for an example of using this. Also give ngctl(8) the ability to print out incoming data and control messages at any time. Eventually nghook(8) may be subsumed. Several other misc. bug fixes. Reviewed by: julian
268 lines
8.5 KiB
Groff
268 lines
8.5 KiB
Groff
.\" Copyright (c) 1996-1999 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@whistle.com>
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.\"
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.\" $FreeBSD$
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.\" $Whistle: netgraph.3,v 1.7 1999/01/25 07:14:06 archie Exp $
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.\"
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.Dd January 19, 1999
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.Dt NETGRAPH 3
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.Os FreeBSD 3
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.Sh NAME
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.Nm NgMkSockNode ,
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.Nm NgNameNode ,
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.Nm NgSendMsg ,
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.Nm NgRecvMsg ,
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.Nm NgSendData ,
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.Nm NgRecvData ,
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.Nm NgSetDebug ,
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.Nm NgSetErrLog
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.Nd Netgraph user library
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.Sh SYNOPSIS
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.Fd #include <netgraph.h>
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.Ft int
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.Fn NgMkSockNode "const char *name" "int *csp" "int *dsp"
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.Ft int
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.Fn NgNameNode "int cs" "const char *path" "const char *fmt" "..."
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.Ft int
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.Fn NgSendMsg "int cs" "const char *path" "int cookie" "int cmd" "const void *arg" "size_t arglen"
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.Ft int
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.Fn NgSendAsciiMsg "int cs" "const char *path" "const char *fmt" "..."
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.Ft int
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.Fn NgSendMsgReply "int cs" "const char *path" "struct ng_mesg *msg" "const void *arg" "size_t arglen"
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.Ft int
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.Fn NgRecvMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
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.Ft int
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.Fn NgRecvAsciiMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
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.Ft int
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.Fn NgSendData "int ds" "const char *hook" "const u_char *buf" "size_t len"
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.Ft int
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.Fn NgRecvData "int ds" "u_char *buf" "size_t len" "char *hook"
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.Ft int
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.Fn NgSetDebug "int level"
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.Ft void
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.Fn NgSetErrLog "void (*log)(const char *fmt, ...)" "void (*logx)(const char *fmt, ...)"
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.Sh DESCRIPTION
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These functions facilitate user-mode program participation in the kernel
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.Xr netgraph 4
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graph-based networking system, by utilizing the netgraph
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.Em socket
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node type (see
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.Xr ng_socket 8 ")."
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.Pp
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.Fn NgMkSockNode
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should be called first, to create a new
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.Em socket
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type netgraph node with associated control and data sockets. If
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.Fa name
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is non-NULL, the node will have that global name assigned to it.
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.Fa "*csp"
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and
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.Fa "*dsp"
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will be set to the newly opened control and data sockets
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associated with the node; either
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.Fa "csp"
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or
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.Fa "dsp"
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may be NULL if only one socket is desired.
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.Pp
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.Fn NgNameNode
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assigns a global name to the node addressed by
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.Fa path .
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.Pp
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.Fn NgSendMsg
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sends a binary control message from the socket node associated
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with control socket
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.Fa cs
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to the node addressed by
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.Fa path .
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The
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.Fa cookie
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indicates how to interpret
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.Fa cmd ,
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which indicates a specific command.
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Extra argument data (if any) is specified by
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.Fa arg
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and
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.Fa arglen .
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The
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.Fa cookie ,
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.Fa cmd ,
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and argument data are defined by the header file corresponding
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to the type of the node being addressed.
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.Pp
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Use
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.Fn NgSendMsgReply
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to send reply to a previously received control message.
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The original message header should be pointed to by
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.Fa msg .
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.Pp
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.Fn NgSendAsciiMsg
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performs the same function as
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.Fn NgSendMsg ,
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but adds support for ASCII encoding of control messages.
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.Fn NgSendAsciiMsg
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formats its input a la
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.Xr printf 3
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and then sends the resulting ASCII string to the node in a
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.Dv NGM_ASCII2BINARY
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control message. The node returns a binary version of the
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message, which is then sent back to the node just as with
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.Fn NgSendMsg .
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Note that ASCII conversion may not be supported by all node types.
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.Pp
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.Fn NgRecvMsg
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reads the next control message received by the node associated with
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control socket
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.Fa cs .
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The message and any extra argument data must fit in
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.Fa replen
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bytes.
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If
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.Fa "path"
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is non-NULL, it must point to a buffer of at least
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.Dv "NG_PATHLEN + 1"
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bytes, which will be filled in (and NUL terminated) with the path to
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the node from which the message was received.
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.Pp
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.Fn NgRecvAsciiMsg
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works exactly like
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.Fn NgRecvMsg ,
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except that after the message is received, any binary arguments
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are converted to ASCII by sending a
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.Dv NGM_BINARY2ASCII
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request back to the originating node. The result is the same as
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.Fn NgRecvAsciiMsg ,
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with the exception that the reply arguments field will contain
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a NUL-terminated ASCII version of the arguments (and the reply
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header argument length field will be adjusted).
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.Pp
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.Fn NgSendData
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writes a data packet out on the specified hook of the node corresponding
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to data socket
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.Fa ds .
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The node must already be connected to some other node via that hook.
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.Pp
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.Fn NgRecvData
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reads the next data packet (of up to
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.Fa len
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bytes) received by the node corresponding to data socket
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.Fa ds
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and stores it in
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.Fa buf ,
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which must be large enough to hold the entire packet. If
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.Fa "hook"
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is non-NULL, it must point to a buffer of at least
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.Dv "NG_HOOKLEN + 1"
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bytes, which will be filled in (and NUL terminated) with the name of
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the hook on which the data was received.
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.Pp
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.Fn NgSetDebug
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and
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.Fn NgSetErrLog
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are used for debugging.
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.Fn NgSetDebug
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sets the debug level (if non-negative), and returns the old setting.
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Higher debug levels result in more verbosity. The default is zero.
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All debug and error messages are logged via the functions
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specified in the most recent call to
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.Fn NgSetErrLog .
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The default logging functions are
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.Xr vwarn 3
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and
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.Xr vwarnx 3 .
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.Pp
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At debug level 3, the library attempts to display control message arguments
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in ASCII format; however, this results in additional messages being
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sent which may interfere with debugging. At even higher levels,
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even these additional messagages will be displayed, etc.
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.Pp
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Note that
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.Xr select 2
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can be used on the data and the control sockets to detect the presence of
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incoming data and control messages, respectively.
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Data and control packets are always written and read atomically, i.e.,
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in one whole piece.
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.Pp
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User mode programs must be linked with the
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.Dv -lnetgraph
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flag to link in this library.
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.Sh INITIALIZATION
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To enable Netgraph in your kernel, either your kernel must be
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compiled with ``options NETGRAPH'' in the kernel configuration
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file, or else the
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.Xr netgraph 4
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and
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.Xr ng_socket 8
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KLD modules must have been loaded via
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.Xr kldload 8 .
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.Sh DIAGNOSTICS
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All functions except
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.Fn NgSetDebug
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and
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.Fn NgSetErrLog
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return -1 if there was an error and set errno accordingly.
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.Pp
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For
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.Fn NgSendAsciiMsg
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and
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.Fn NgRecvAsciiMsg ,
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the following additional errors are possible:
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.Bl -tag -width Er
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.It Bq Er ENOSYS
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The node type does not know how to encode or decode the control message.
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.It Bq Er ERANGE
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The encoded or decoded arguments were too long for the supplied buffer.
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.It Bq Er ENOENT
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An unknown structure field was seen in an ASCII control message.
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.It Bq Er EALREADY
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The same structure field was specified twice in an ASCII control message.
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.It Bq Er EINVAL
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ASCII control message parse error or illegal value.
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.It Bq Er E2BIG
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ASCII control message array or fixed width string buffer overflow.
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.El
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.Sh SEE ALSO
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.Xr netgraph 4 ,
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.Xr socket 2 ,
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.Xr select 2 ,
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.Xr warnx 3 ,
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.Xr ng_socket 8 .
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.Sh HISTORY
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The
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.Em netgraph
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system was designed and first implemented at Whistle Communications, Inc. in
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a version FreeBSD 2.2 customized for the Whistle InterJet.
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.Sh AUTHOR
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.An Archie Cobbs <archie@whistle.com>
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