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 3 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 8 ) . 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. 127.Pp 128Use 129.Fn NgSendMsgReply 130to send reply to a previously received control message. 131The original message header should be pointed to by 132.Fa msg . 133.Pp 134.Fn NgSendAsciiMsg 135performs the same function as 136.Fn NgSendMsg , 137but adds support for 138.Tn ASCII 139encoding of control messages. 140.Fn NgSendAsciiMsg 141formats its input a la 142.Xr printf 3 143and then sends the resulting 144.Tn ASCII 145string to the node in a 146.Dv NGM_ASCII2BINARY 147control message. The node returns a binary version of the 148message, which is then sent back to the node just as with 149.Fn NgSendMsg . 150Note that 151.Tn ASCII 152conversion may not be supported by all node types. 153.Pp 154.Fn NgRecvMsg 155reads the next control message received by the node associated with 156control socket 157.Fa cs . 158The message and any extra argument data must fit in 159.Fa replen 160bytes. 161If 162.Fa "path" 163is non-NULL, it must point to a buffer of at least 164.Dv "NG_PATHLEN + 1" 165bytes, which will be filled in (and NUL terminated) with the path to 166the node from which the message was received. 167.Pp 168.Fn NgRecvAsciiMsg 169works exactly like 170.Fn NgRecvMsg , 171except that after the message is received, any binary arguments 172are converted to 173.Tn ASCII 174by sending a 175.Dv NGM_BINARY2ASCII 176request back to the originating node. The result is the same as 177.Fn NgRecvAsciiMsg , 178with the exception that the reply arguments field will contain 179a NUL-terminated 180.Tn ASCII 181version of the arguments (and the reply 182header argument length field will be adjusted). 183.Pp 184.Fn NgSendData 185writes a data packet out on the specified hook of the node corresponding 186to data socket 187.Fa ds . 188The node must already be connected to some other node via that hook. 189.Pp 190.Fn NgRecvData 191reads the next data packet (of up to 192.Fa len 193bytes) received by the node corresponding to data socket 194.Fa ds 195and stores it in 196.Fa buf , 197which must be large enough to hold the entire packet. If 198.Fa "hook" 199is non-NULL, it must point to a buffer of at least 200.Dv "NG_HOOKLEN + 1" 201bytes, which will be filled in (and NUL terminated) with the name of 202the hook on which the data was received. 203.Pp 204.Fn NgSetDebug 205and 206.Fn NgSetErrLog 207are used for debugging. 208.Fn NgSetDebug 209sets the debug level (if non-negative), and returns the old setting. 210Higher debug levels result in more verbosity. The default is zero. 211All debug and error messages are logged via the functions 212specified in the most recent call to 213.Fn NgSetErrLog . 214The default logging functions are 215.Xr vwarn 3 216and 217.Xr vwarnx 3 . 218.Pp 219At debug level 3, the library attempts to display control message arguments 220in 221.Tn ASCII 222format; however, this results in additional messages being 223sent which may interfere with debugging. At even higher levels, 224even these additional messagages will be displayed, etc. 225.Pp 226Note that 227.Xr select 2 228can be used on the data and the control sockets to detect the presence of 229incoming data and control messages, respectively. 230Data and control packets are always written and read atomically, i.e., 231in one whole piece. 232.Pp 233User mode programs must be linked with the 234.Dv -lnetgraph 235flag to link in this library. 236.Sh INITIALIZATION 237To enable Netgraph in your kernel, either your kernel must be 238compiled with 239.Dq options NETGRAPH 240in the kernel configuration 241file, or else the 242.Xr netgraph 4 243and 244.Xr ng_socket 8 245KLD modules must have been loaded via 246.Xr kldload 8 . 247.Sh DIAGNOSTICS 248All functions except 249.Fn NgSetDebug 250and 251.Fn NgSetErrLog 252return -1 if there was an error and set errno accordingly. 253.Pp 254For 255.Fn NgSendAsciiMsg 256and 257.Fn NgRecvAsciiMsg , 258the following additional errors are possible: 259.Bl -tag -width Er 260.It Bq Er ENOSYS 261The node type does not know how to encode or decode the control message. 262.It Bq Er ERANGE 263The encoded or decoded arguments were too long for the supplied buffer. 264.It Bq Er ENOENT 265An unknown structure field was seen in an 266.Tn ASCII 267control message. 268.It Bq Er EALREADY 269The same structure field was specified twice in an 270.Tn ASCII 271control message. 272.It Bq Er EINVAL 273.Tn ASCII 274control message parse error or illegal value. 275.It Bq Er E2BIG 276ASCII control message array or fixed width string buffer overflow. 277.El 278.Sh SEE ALSO 279.Xr netgraph 4 , 280.Xr kld 4 , 281.Xr socket 2 , 282.Xr select 2 , 283.Xr warnx 3 , 284.Xr ng_socket 8 285.Sh HISTORY 286The 287.Nm netgraph 288system was designed and first implemented at Whistle Communications, Inc. in 289a version of 290.Fx 2.2 291customized for the Whistle InterJet. 292.Sh AUTHORS 293.An Archie Cobbs Aq archie@whistle.com 294