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.\" $FreeBSD$ 36.\" $Whistle: netgraph.3,v 1.7 1999/01/25 07:14:06 archie Exp $ 37.\" 38.Dd January 19, 1999 39.Dt NETGRAPH 3 40.Os 41.Sh NAME 42.Nm NgMkSockNode , 43.Nm NgNameNode , 44.Nm NgSendMsg , 45.Nm NgRecvMsg , 46.Nm NgSendData , 47.Nm NgRecvData , 48.Nm NgSetDebug , 49.Nm NgSetErrLog 50.Nd netgraph user library 51.Sh LIBRARY 52.Lb libnetgraph 53.Sh SYNOPSIS 54.In netgraph.h 55.Ft int 56.Fn NgMkSockNode "const char *name" "int *csp" "int *dsp" 57.Ft int 58.Fn NgNameNode "int cs" "const char *path" "const char *fmt" "..." 59.Ft int 60.Fn NgSendMsg "int cs" "const char *path" "int cookie" "int cmd" "const void *arg" "size_t arglen" 61.Ft int 62.Fn NgSendAsciiMsg "int cs" "const char *path" "const char *fmt" "..." 63.Ft int 64.Fn NgSendMsgReply "int cs" "const char *path" "struct ng_mesg *msg" "const void *arg" "size_t arglen" 65.Ft int 66.Fn NgRecvMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path" 67.Ft int 68.Fn NgRecvAsciiMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path" 69.Ft int 70.Fn NgSendData "int ds" "const char *hook" "const u_char *buf" "size_t len" 71.Ft int 72.Fn NgRecvData "int ds" "u_char *buf" "size_t len" "char *hook" 73.Ft int 74.Fn NgSetDebug "int level" 75.Ft void 76.Fn NgSetErrLog "void (*log)(const char *fmt, ...)" "void (*logx)(const char *fmt, ...)" 77.Sh DESCRIPTION 78These functions facilitate user-mode program participation in the kernel 79.Xr netgraph 4 80graph-based networking system, by utilizing the netgraph 81.Em socket 82node type (see 83.Xr ng_socket 4 ) . 84.Pp 85.Fn NgMkSockNode 86should be called first, to create a new 87.Em socket 88type netgraph node with associated control and data sockets. If 89.Fa name 90is non-NULL, the node will have that global name assigned to it. 91.Fa "*csp" 92and 93.Fa "*dsp" 94will be set to the newly opened control and data sockets 95associated with the node; either 96.Fa "csp" 97or 98.Fa "dsp" 99may be NULL if only one socket is desired. 100.Fn NgMkSockNode 101loads the socket node type KLD if it's not already loaded. 102.Pp 103.Fn NgNameNode 104assigns a global name to the node addressed by 105.Fa path . 106.Pp 107.Fn NgSendMsg 108sends a binary control message from the socket node associated 109with control socket 110.Fa cs 111to the node addressed by 112.Fa path . 113The 114.Fa cookie 115indicates how to interpret 116.Fa cmd , 117which indicates a specific command. 118Extra argument data (if any) is specified by 119.Fa arg 120and 121.Fa arglen . 122The 123.Fa cookie , 124.Fa cmd , 125and argument data are defined by the header file corresponding 126to the type of the node being addressed. 127The unique, non-negative token value chosen for use in the message 128header is returned. This value is typically used to associate replies. 129.Pp 130Use 131.Fn NgSendMsgReply 132to send reply to a previously received control message. 133The original message header should be pointed to by 134.Fa msg . 135.Pp 136.Fn NgSendAsciiMsg 137performs the same function as 138.Fn NgSendMsg , 139but adds support for 140.Tn ASCII 141encoding of control messages. 142.Fn NgSendAsciiMsg 143formats its input a la 144.Xr printf 3 145and then sends the resulting 146.Tn ASCII 147string to the node in a 148.Dv NGM_ASCII2BINARY 149control message. The node returns a binary version of the 150message, which is then sent back to the node just as with 151.Fn NgSendMsg . 152As with 153.Fn NgSendMsg , 154the message token value is returned. 155Note that 156.Tn ASCII 157conversion may not be supported by all node types. 158.Pp 159.Fn NgRecvMsg 160reads the next control message received by the node associated with 161control socket 162.Fa cs . 163The message and any extra argument data must fit in 164.Fa replen 165bytes. 166If 167.Fa "path" 168is non-NULL, it must point to a buffer of at least 169.Dv "NG_PATHLEN + 1" 170bytes, which will be filled in (and NUL terminated) with the path to 171the node from which the message was received. 172.Pp 173The length of the control message is returned. 174A return value of zero indicates that the socket was closed. 175.Pp 176.Fn NgRecvAsciiMsg 177works exactly like 178.Fn NgRecvMsg , 179except that after the message is received, any binary arguments 180are converted to 181.Tn ASCII 182by sending a 183.Dv NGM_BINARY2ASCII 184request back to the originating node. The result is the same as 185.Fn NgRecvAsciiMsg , 186with the exception that the reply arguments field will contain 187a NUL-terminated 188.Tn ASCII 189version of the arguments (and the reply 190header argument length field will be adjusted). 191.Pp 192.Fn NgSendData 193writes a data packet out on the specified hook of the node corresponding 194to data socket 195.Fa ds . 196The node must already be connected to some other node via that hook. 197.Pp 198.Fn NgRecvData 199reads the next data packet (of up to 200.Fa len 201bytes) received by the node corresponding to data socket 202.Fa ds 203and stores it in 204.Fa buf , 205which must be large enough to hold the entire packet. If 206.Fa "hook" 207is non-NULL, it must point to a buffer of at least 208.Dv "NG_HOOKLEN + 1" 209bytes, which will be filled in (and NUL terminated) with the name of 210the hook on which the data was received. 211.Pp 212The length of the packet is returned. 213A return value of zero indicates that the socket was closed. 214.Pp 215.Fn NgSetDebug 216and 217.Fn NgSetErrLog 218are used for debugging. 219.Fn NgSetDebug 220sets the debug level (if non-negative), and returns the old setting. 221Higher debug levels result in more verbosity. The default is zero. 222All debug and error messages are logged via the functions 223specified in the most recent call to 224.Fn NgSetErrLog . 225The default logging functions are 226.Xr vwarn 3 227and 228.Xr vwarnx 3 . 229.Pp 230At debug level 3, the library attempts to display control message arguments 231in 232.Tn ASCII 233format; however, this results in additional messages being 234sent which may interfere with debugging. At even higher levels, 235even these additional messagages will be displayed, etc. 236.Pp 237Note that 238.Xr select 2 239can be used on the data and the control sockets to detect the presence of 240incoming data and control messages, respectively. 241Data and control packets are always written and read atomically, i.e., 242in one whole piece. 243.Pp 244User mode programs must be linked with the 245.Dv -lnetgraph 246flag to link in this library. 247.Sh INITIALIZATION 248To enable Netgraph in your kernel, either your kernel must be 249compiled with 250.Dq options NETGRAPH 251in the kernel configuration 252file, or else the 253.Xr netgraph 4 254and 255.Xr ng_socket 4 256KLD modules must have been loaded via 257.Xr kldload 8 . 258.Sh RETURN VALUES 259.Fn NgSetDebug 260returns the previous debug setting. 261.Fn NgSetErrLog 262has no return value. 263All other functions return \-1 if there was an error and set 264.Va errno 265accordingly. 266A return value of zero from 267.Fn NgRecvMsg 268or 269.Fn NgRecvData 270indicates that the netgraph socket has been closed. 271.Pp 272For 273.Fn NgSendAsciiMsg 274and 275.Fn NgRecvAsciiMsg , 276the following additional errors are possible: 277.Bl -tag -width Er 278.It Bq Er ENOSYS 279The node type does not know how to encode or decode the control message. 280.It Bq Er ERANGE 281The encoded or decoded arguments were too long for the supplied buffer. 282.It Bq Er ENOENT 283An unknown structure field was seen in an 284.Tn ASCII 285control message. 286.It Bq Er EALREADY 287The same structure field was specified twice in an 288.Tn ASCII 289control message. 290.It Bq Er EINVAL 291.Tn ASCII 292control message parse error or illegal value. 293.It Bq Er E2BIG 294ASCII control message array or fixed width string buffer overflow. 295.El 296.Sh SEE ALSO 297.Xr select 2 , 298.Xr socket 2 , 299.Xr warnx 3 , 300.Xr kld 4 , 301.Xr netgraph 4 , 302.Xr ng_socket 4 303.Sh HISTORY 304The 305.Nm netgraph 306system was designed and first implemented at Whistle Communications, Inc. in 307a version of 308.Fx 2.2 309customized for the Whistle InterJet. 310.Sh AUTHORS 311.An Archie Cobbs Aq archie@whistle.com 312