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1 .\" Copyright (c) 1996-1999 Whistle Communications, Inc.
2 .\" All rights reserved.
3 .\"
4 .\" Subject to the following obligations and disclaimer of warranty, use and
5 .\" redistribution of this software, in source or object code forms, with or
6 .\" without modifications are expressly permitted by Whistle Communications;
7 .\" provided, however, that:
8 .\" 1. Any and all reproductions of the source or object code must include the
9 .\" copyright notice above and the following disclaimer of warranties; and
10 .\" 2. No rights are granted, in any manner or form, to use Whistle
11 .\" Communications, Inc. trademarks, including the mark "WHISTLE
12 .\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as
13 .\" such appears in the above copyright notice or in the software.
14 .\"
15 .\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
16 .\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
17 .\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
18 .\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
19 .\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
20 .\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
21 .\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
22 .\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
23 .\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
24 .\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
25 .\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
26 .\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
27 .\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
28 .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 .\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
31 .\" OF SUCH DAMAGE.
32 .\"
33 .\" Author: Archie Cobbs <archie@whistle.com>
34 .\"
35 .\" $FreeBSD: src/lib/libnetgraph/netgraph.3,v 1.4.2.10 2002/12/29 16:35:36 schweikh Exp $
36 .\" $DragonFly: src/lib/libnetgraph/netgraph.3,v 1.5 2007/06/03 23:41:25 swildner Exp $
37 .\" $Whistle: netgraph.3,v 1.7 1999/01/25 07:14:06 archie Exp $
38 .\"
39 .Dd January 19, 1999
40 .Dt NETGRAPH 3
41 .Os
42 .Sh NAME
43 .Nm NgMkSockNode ,
44 .Nm NgNameNode ,
45 .Nm NgSendMsg ,
46 .Nm NgSendAsciiMsg ,
47 .Nm NgSendReplyMsg ,
48 .Nm NgRecvMsg ,
49 .Nm NgRecvAsciiMsg ,
50 .Nm NgSendData ,
51 .Nm NgRecvData ,
52 .Nm NgSetDebug ,
53 .Nm NgSetErrLog
54 .Nd netgraph user library
55 .Sh LIBRARY
56 .Lb libnetgraph
57 .Sh SYNOPSIS
58 .In netgraph.h
59 .Ft int
60 .Fn NgMkSockNode "const char *name" "int *csp" "int *dsp"
61 .Ft int
62 .Fn NgNameNode "int cs" "const char *path" "const char *fmt" "..."
63 .Ft int
64 .Fn NgSendMsg "int cs" "const char *path" "int cookie" "int cmd" "const void *arg" "size_t arglen"
65 .Ft int
66 .Fn NgSendAsciiMsg "int cs" "const char *path" "const char *fmt" "..."
67 .Ft int
68 .Fn NgSendReplyMsg "int cs" "const char *path" "struct ng_mesg *msg" "const void *arg" "size_t arglen"
69 .Ft int
70 .Fn NgRecvMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
71 .Ft int
72 .Fn NgRecvAsciiMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
73 .Ft int
74 .Fn NgSendData "int ds" "const char *hook" "const u_char *buf" "size_t len"
75 .Ft int
76 .Fn NgRecvData "int ds" "u_char *buf" "size_t len" "char *hook"
77 .Ft int
78 .Fn NgSetDebug "int level"
79 .Ft void
80 .Fn NgSetErrLog "void (*log)(const char *fmt, ...)" "void (*logx)(const char *fmt, ...)"
81 .Sh DESCRIPTION
82 These functions facilitate user-mode program participation in the kernel
83 .Xr netgraph 4
84 graph-based networking system, by utilizing the netgraph
85 .Em socket
86 node type (see
87 .Xr ng_socket 4 ) .
88 .Pp
89 .Fn NgMkSockNode
90 should be called first, to create a new
91 .Em socket
92 type netgraph node with associated control and data sockets. If
93 .Fa name
94 is non-NULL, the node will have that global name assigned to it.
95 .Fa "*csp"
96 and
97 .Fa "*dsp"
98 will be set to the newly opened control and data sockets
99 associated with the node; either
100 .Fa "csp"
101 or
102 .Fa "dsp"
103 may be NULL if only one socket is desired.
104 .Fn NgMkSockNode
105 loads the socket node type KLD if it's not already loaded.
106 .Pp
107 .Fn NgNameNode
108 assigns a global name to the node addressed by
109 .Fa path .
110 .Pp
111 .Fn NgSendMsg
112 sends a binary control message from the socket node associated
113 with control socket
114 .Fa cs
115 to the node addressed by
116 .Fa path .
117 The
118 .Fa cookie
119 indicates how to interpret
120 .Fa cmd ,
121 which indicates a specific command.
122 Extra argument data (if any) is specified by
123 .Fa arg
124 and
125 .Fa arglen .
126 The
127 .Fa cookie ,
128 .Fa cmd ,
129 and argument data are defined by the header file corresponding
130 to the type of the node being addressed.
131 The unique, non-negative token value chosen for use in the message
132 header is returned. This value is typically used to associate replies.
133 .Pp
134 Use
135 .Fn NgSendReplyMsg
136 to send reply to a previously received control message.
137 The original message header should be pointed to by
138 .Fa msg .
139 .Pp
140 .Fn NgSendAsciiMsg
141 performs the same function as
142 .Fn NgSendMsg ,
143 but adds support for
144 .Tn ASCII
145 encoding of control messages.
146 .Fn NgSendAsciiMsg
147 formats its input a la
148 .Xr printf 3
149 and then sends the resulting
150 .Tn ASCII
151 string to the node in a
152 .Dv NGM_ASCII2BINARY
153 control message. The node returns a binary version of the
154 message, which is then sent back to the node just as with
155 .Fn NgSendMsg .
156 As with
157 .Fn NgSendMsg ,
158 the message token value is returned.
159 Note that
160 .Tn ASCII
161 conversion may not be supported by all node types.
162 .Pp
163 .Fn NgRecvMsg
164 reads the next control message received by the node associated with
165 control socket
166 .Fa cs .
167 The message and any extra argument data must fit in
168 .Fa replen
169 bytes.
170 If
171 .Fa "path"
172 is non-NULL, it must point to a buffer of at least
173 .Dv "NG_PATHSIZ"
174 bytes, which will be filled in (and NUL terminated) with the path to
175 the node from which the message was received.
176 .Pp
177 The length of the control message is returned.
178 A return value of zero indicates that the socket was closed.
179 .Pp
180 .Fn NgRecvAsciiMsg
181 works exactly like
182 .Fn NgRecvMsg ,
183 except that after the message is received, any binary arguments
184 are converted to
185 .Tn ASCII
186 by sending a
187 .Dv NGM_BINARY2ASCII
188 request back to the originating node. The result is the same as
189 .Fn NgRecvAsciiMsg ,
190 with the exception that the reply arguments field will contain
191 a NUL-terminated
192 .Tn ASCII
193 version of the arguments (and the reply
194 header argument length field will be adjusted).
195 .Pp
196 .Fn NgSendData
197 writes a data packet out on the specified hook of the node corresponding
198 to data socket
199 .Fa ds .
200 The node must already be connected to some other node via that hook.
201 .Pp
202 .Fn NgRecvData
203 reads the next data packet (of up to
204 .Fa len
205 bytes) received by the node corresponding to data socket
206 .Fa ds
207 and stores it in
208 .Fa buf ,
209 which must be large enough to hold the entire packet. If
210 .Fa "hook"
211 is non-NULL, it must point to a buffer of at least
212 .Dv "NG_HOOKSIZ"
213 bytes, which will be filled in (and NUL terminated) with the name of
214 the hook on which the data was received.
215 .Pp
216 The length of the packet is returned.
217 A return value of zero indicates that the socket was closed.
218 .Pp
219 .Fn NgSetDebug
220 and
221 .Fn NgSetErrLog
222 are used for debugging.
223 .Fn NgSetDebug
224 sets the debug level (if non-negative), and returns the old setting.
225 Higher debug levels result in more verbosity. The default is zero.
226 All debug and error messages are logged via the functions
227 specified in the most recent call to
228 .Fn NgSetErrLog .
229 The default logging functions are
230 .Xr vwarn 3
231 and
232 .Xr vwarnx 3 .
233 .Pp
234 At debug level 3, the library attempts to display control message arguments
235 in
236 .Tn ASCII
237 format; however, this results in additional messages being
238 sent which may interfere with debugging. At even higher levels,
239 even these additional messages will be displayed, etc.
240 .Pp
241 Note that
242 .Xr select 2
243 can be used on the data and the control sockets to detect the presence of
244 incoming data and control messages, respectively.
245 Data and control packets are always written and read atomically, i.e.,
246 in one whole piece.
247 .Pp
248 User mode programs must be linked with the
249 .Dv -lnetgraph
250 flag to link in this library.
251 .Sh INITIALIZATION
252 To enable Netgraph in your kernel, either your kernel must be
253 compiled with
254 .Cd options NETGRAPH
255 in the kernel configuration
256 file, or else the
257 .Xr netgraph 4
258 and
259 .Xr ng_socket 4
260 KLD modules must have been loaded via
261 .Xr kldload 8 .
262 .Sh RETURN VALUES
263 .Fn NgSetDebug
264 returns the previous debug setting.
265 .Fn NgSetErrLog
266 has no return value.
267 All other functions return \-1 if there was an error and set
268 .Va errno
269 accordingly.
270 A return value of zero from
271 .Fn NgRecvMsg
272 or
273 .Fn NgRecvData
274 indicates that the netgraph socket has been closed.
275 .Pp
276 For
277 .Fn NgSendAsciiMsg
278 and
279 .Fn NgRecvAsciiMsg ,
280 the following additional errors are possible:
281 .Bl -tag -width Er
282 .It Bq Er ENOSYS
283 The node type does not know how to encode or decode the control message.
284 .It Bq Er ERANGE
285 The encoded or decoded arguments were too long for the supplied buffer.
286 .It Bq Er ENOENT
287 An unknown structure field was seen in an
288 .Tn ASCII
289 control message.
290 .It Bq Er EALREADY
291 The same structure field was specified twice in an
292 .Tn ASCII
293 control message.
294 .It Bq Er EINVAL
295 .Tn ASCII
296 control message parse error or illegal value.
297 .It Bq Er E2BIG
298 ASCII control message array or fixed width string buffer overflow.
299 .El
300 .Sh SEE ALSO
301 .Xr select 2 ,
302 .Xr socket 2 ,
303 .Xr warnx 3 ,
304 .Xr kld 4 ,
305 .Xr netgraph 4 ,
306 .Xr ng_socket 4
307 .Sh HISTORY
308 The
309 .Nm netgraph
310 system was designed and first implemented at Whistle Communications, Inc. in
311 a version of
312 .Fx 2.2
313 customized for the Whistle InterJet.
314 .Sh AUTHORS
315 .An Archie Cobbs Aq archie@whistle.com