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.\" $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 NgSendAsciiMsg , 46.Nm NgSendReplyMsg , 47.Nm NgRecvMsg , 48.Nm NgRecvAsciiMsg , 49.Nm NgSendData , 50.Nm NgRecvData , 51.Nm NgSetDebug , 52.Nm NgSetErrLog 53.Nd netgraph user library 54.Sh LIBRARY 55.Lb libnetgraph 56.Sh SYNOPSIS 57.In netgraph.h 58.Ft int 59.Fn NgMkSockNode "const char *name" "int *csp" "int *dsp" 60.Ft int 61.Fn NgNameNode "int cs" "const char *path" "const char *fmt" "..." 62.Ft int 63.Fn NgSendMsg "int cs" "const char *path" "int cookie" "int cmd" "const void *arg" "size_t arglen" 64.Ft int 65.Fn NgSendAsciiMsg "int cs" "const char *path" "const char *fmt" "..." 66.Ft int 67.Fn NgSendReplyMsg "int cs" "const char *path" "const struct ng_mesg *msg" "const void *arg" "size_t arglen" 68.Ft int 69.Fn NgRecvMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path" 70.Ft int 71.Fn NgRecvAsciiMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path" 72.Ft int 73.Fn NgSendData "int ds" "const char *hook" "const u_char *buf" "size_t len" 74.Ft int 75.Fn NgRecvData "int ds" "u_char *buf" "size_t len" "char *hook" 76.Ft int 77.Fn NgSetDebug "int level" 78.Ft void 79.Fn NgSetErrLog "void (*log)(const char *fmt, ...)" "void (*logx)(const char *fmt, ...)" 80.Sh DESCRIPTION 81These functions facilitate user-mode program participation in the kernel 82.Xr netgraph 4 83graph-based networking system, by utilizing the netgraph 84.Em socket 85node type (see 86.Xr ng_socket 4 ) . 87.Pp 88.Fn NgMkSockNode 89should be called first, to create a new 90.Em socket 91type netgraph node with associated control and data sockets. If 92.Fa name 93is non-NULL, the node will have that global name assigned to it. 94.Fa "*csp" 95and 96.Fa "*dsp" 97will be set to the newly opened control and data sockets 98associated with the node; either 99.Fa "csp" 100or 101.Fa "dsp" 102may be NULL if only one socket is desired. 103.Fn NgMkSockNode 104loads the socket node type KLD if it's not already loaded. 105.Pp 106.Fn NgNameNode 107assigns a global name to the node addressed by 108.Fa path . 109.Pp 110.Fn NgSendMsg 111sends a binary control message from the socket node associated 112with control socket 113.Fa cs 114to the node addressed by 115.Fa path . 116The 117.Fa cookie 118indicates how to interpret 119.Fa cmd , 120which indicates a specific command. 121Extra argument data (if any) is specified by 122.Fa arg 123and 124.Fa arglen . 125The 126.Fa cookie , 127.Fa cmd , 128and argument data are defined by the header file corresponding 129to the type of the node being addressed. 130The unique, non-negative token value chosen for use in the message 131header is returned. This value is typically used to associate replies. 132.Pp 133Use 134.Fn NgSendReplyMsg 135to send reply to a previously received control message. 136The original message header should be pointed to by 137.Fa msg . 138.Pp 139.Fn NgSendAsciiMsg 140performs the same function as 141.Fn NgSendMsg , 142but adds support for 143.Tn ASCII 144encoding of control messages. 145.Fn NgSendAsciiMsg 146formats its input a la 147.Xr printf 3 148and then sends the resulting 149.Tn ASCII 150string to the node in a 151.Dv NGM_ASCII2BINARY 152control message. The node returns a binary version of the 153message, which is then sent back to the node just as with 154.Fn NgSendMsg . 155As with 156.Fn NgSendMsg , 157the message token value is returned. 158Note that 159.Tn ASCII 160conversion may not be supported by all node types. 161.Pp 162.Fn NgRecvMsg 163reads the next control message received by the node associated with 164control socket 165.Fa cs . 166The message and any extra argument data must fit in 167.Fa replen 168bytes. 169If 170.Fa "path" 171is non-NULL, it must point to a buffer of at least 172.Dv "NG_PATHSIZ" 173bytes, which will be filled in (and NUL terminated) with the path to 174the node from which the message was received. 175.Pp 176The length of the control message is returned. 177A return value of zero indicates that the socket was closed. 178.Pp 179.Fn NgRecvAsciiMsg 180works exactly like 181.Fn NgRecvMsg , 182except that after the message is received, any binary arguments 183are converted to 184.Tn ASCII 185by sending a 186.Dv NGM_BINARY2ASCII 187request back to the originating node. The result is the same as 188.Fn NgRecvAsciiMsg , 189with the exception that the reply arguments field will contain 190a NUL-terminated 191.Tn ASCII 192version of the arguments (and the reply 193header argument length field will be adjusted). 194.Pp 195.Fn NgSendData 196writes a data packet out on the specified hook of the node corresponding 197to data socket 198.Fa ds . 199The node must already be connected to some other node via that hook. 200.Pp 201.Fn NgRecvData 202reads the next data packet (of up to 203.Fa len 204bytes) received by the node corresponding to data socket 205.Fa ds 206and stores it in 207.Fa buf , 208which must be large enough to hold the entire packet. If 209.Fa "hook" 210is non-NULL, it must point to a buffer of at least 211.Dv "NG_HOOKSIZ" 212bytes, which will be filled in (and NUL terminated) with the name of 213the hook on which the data was received. 214.Pp 215The length of the packet is returned. 216A return value of zero indicates that the socket was closed. 217.Pp 218.Fn NgSetDebug 219and 220.Fn NgSetErrLog 221are used for debugging. 222.Fn NgSetDebug 223sets the debug level (if non-negative), and returns the old setting. 224Higher debug levels result in more verbosity. The default is zero. 225All debug and error messages are logged via the functions 226specified in the most recent call to 227.Fn NgSetErrLog . 228The default logging functions are 229.Xr vwarn 3 230and 231.Xr vwarnx 3 . 232.Pp 233At debug level 3, the library attempts to display control message arguments 234in 235.Tn ASCII 236format; however, this results in additional messages being 237sent which may interfere with debugging. At even higher levels, 238even these additional messages will be displayed, etc. 239.Pp 240Note that 241.Xr select 2 242can be used on the data and the control sockets to detect the presence of 243incoming data and control messages, respectively. 244Data and control packets are always written and read atomically, i.e., 245in one whole piece. 246.Pp 247User mode programs must be linked with the 248.Dv -lnetgraph 249flag to link in this library. 250.Sh INITIALIZATION 251To enable Netgraph in your kernel, either your kernel must be 252compiled with 253.Cd options NETGRAPH 254in the kernel configuration 255file, or else the 256.Xr netgraph 4 257and 258.Xr ng_socket 4 259KLD modules must have been loaded via 260.Xr kldload 8 . 261.Sh RETURN VALUES 262.Fn NgSetDebug 263returns the previous debug setting. 264.Fn NgSetErrLog 265has no return value. 266All other functions return \-1 if there was an error and set 267.Va errno 268accordingly. 269A return value of zero from 270.Fn NgRecvMsg 271or 272.Fn NgRecvData 273indicates that the netgraph socket has been closed. 274.Pp 275For 276.Fn NgSendAsciiMsg 277and 278.Fn NgRecvAsciiMsg , 279the following additional errors are possible: 280.Bl -tag -width Er 281.It Bq Er ENOSYS 282The node type does not know how to encode or decode the control message. 283.It Bq Er ERANGE 284The encoded or decoded arguments were too long for the supplied buffer. 285.It Bq Er ENOENT 286An unknown structure field was seen in an 287.Tn ASCII 288control message. 289.It Bq Er EALREADY 290The same structure field was specified twice in an 291.Tn ASCII 292control message. 293.It Bq Er EINVAL 294.Tn ASCII 295control message parse error or illegal value. 296.It Bq Er E2BIG 297ASCII control message array or fixed width string buffer overflow. 298.El 299.Sh SEE ALSO 300.Xr select 2 , 301.Xr socket 2 , 302.Xr warnx 3 , 303.Xr kld 4 , 304.Xr netgraph 4 , 305.Xr ng_socket 4 306.Sh HISTORY 307The 308.Nm netgraph 309system was designed and first implemented at Whistle Communications, Inc. in 310a version of 311.Fx 2.2 312customized for the Whistle InterJet. 313.Sh AUTHORS 314.An Archie Cobbs Aq Mt archie@whistle.com 315