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 FreeBSD 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.Fd #include <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 173.Fn NgRecvAsciiMsg 174works exactly like 175.Fn NgRecvMsg , 176except that after the message is received, any binary arguments 177are converted to 178.Tn ASCII 179by sending a 180.Dv NGM_BINARY2ASCII 181request back to the originating node. The result is the same as 182.Fn NgRecvAsciiMsg , 183with the exception that the reply arguments field will contain 184a NUL-terminated 185.Tn ASCII 186version of the arguments (and the reply 187header argument length field will be adjusted). 188.Pp 189.Fn NgSendData 190writes a data packet out on the specified hook of the node corresponding 191to data socket 192.Fa ds . 193The node must already be connected to some other node via that hook. 194.Pp 195.Fn NgRecvData 196reads the next data packet (of up to 197.Fa len 198bytes) received by the node corresponding to data socket 199.Fa ds 200and stores it in 201.Fa buf , 202which must be large enough to hold the entire packet. If 203.Fa "hook" 204is non-NULL, it must point to a buffer of at least 205.Dv "NG_HOOKLEN + 1" 206bytes, which will be filled in (and NUL terminated) with the name of 207the hook on which the data was received. 208.Pp 209.Fn NgSetDebug 210and 211.Fn NgSetErrLog 212are used for debugging. 213.Fn NgSetDebug 214sets the debug level (if non-negative), and returns the old setting. 215Higher debug levels result in more verbosity. The default is zero. 216All debug and error messages are logged via the functions 217specified in the most recent call to 218.Fn NgSetErrLog . 219The default logging functions are 220.Xr vwarn 3 221and 222.Xr vwarnx 3 . 223.Pp 224At debug level 3, the library attempts to display control message arguments 225in 226.Tn ASCII 227format; however, this results in additional messages being 228sent which may interfere with debugging. At even higher levels, 229even these additional messagages will be displayed, etc. 230.Pp 231Note that 232.Xr select 2 233can be used on the data and the control sockets to detect the presence of 234incoming data and control messages, respectively. 235Data and control packets are always written and read atomically, i.e., 236in one whole piece. 237.Pp 238User mode programs must be linked with the 239.Dv -lnetgraph 240flag to link in this library. 241.Sh INITIALIZATION 242To enable Netgraph in your kernel, either your kernel must be 243compiled with 244.Dq options NETGRAPH 245in the kernel configuration 246file, or else the 247.Xr netgraph 4 248and 249.Xr ng_socket 4 250KLD modules must have been loaded via 251.Xr kldload 8 . 252.Sh DIAGNOSTICS 253All functions except 254.Fn NgSetDebug 255and 256.Fn NgSetErrLog 257return -1 if there was an error and set errno accordingly. 258.Pp 259For 260.Fn NgSendAsciiMsg 261and 262.Fn NgRecvAsciiMsg , 263the following additional errors are possible: 264.Bl -tag -width Er 265.It Bq Er ENOSYS 266The node type does not know how to encode or decode the control message. 267.It Bq Er ERANGE 268The encoded or decoded arguments were too long for the supplied buffer. 269.It Bq Er ENOENT 270An unknown structure field was seen in an 271.Tn ASCII 272control message. 273.It Bq Er EALREADY 274The same structure field was specified twice in an 275.Tn ASCII 276control message. 277.It Bq Er EINVAL 278.Tn ASCII 279control message parse error or illegal value. 280.It Bq Er E2BIG 281ASCII control message array or fixed width string buffer overflow. 282.El 283.Sh SEE ALSO 284.Xr socket 2 , 285.Xr select 2 , 286.Xr warnx 3 , 287.Xr netgraph 4 , 288.Xr ng_socket 4 , 289.Xr kld 4 290.Sh HISTORY 291The 292.Nm netgraph 293system was designed and first implemented at Whistle Communications, Inc. in 294a version of 295.Fx 2.2 296customized for the Whistle InterJet. 297.Sh AUTHORS 298.An Archie Cobbs Aq archie@whistle.com 299