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: ng_socket.8,v 1.5 1999/01/25 23:46:27 archie Exp $ 37.\" 38.Dd January 19, 1999 39.Dt NG_SOCKET 8 40.Os FreeBSD 3 41.Sh NAME 42.Nm ng_socket 43.Nd netgraph socket node type 44.Sh SYNOPSIS 45.Fd #include <netgraph/ng_message.h> 46.Fd #include <netgraph/ng_socket.h> 47.Sh DESCRIPTION 48A 49.Nm socket 50node is both a BSD socket and a netgraph node. The 51.Nm socket 52node type allows user-mode processes to participate in the kernel 53.Xr netgraph 4 54networking subsystem using the BSD socket interface. 55.Pp 56A new 57.Nm socket 58node is created by creating a new socket of type 59.Dv NG_CONTROL 60in the protocol family 61.Dv PF_NETGRAPH , 62using the 63.Xr socket 2 64system call. 65Any control messages received by the node are received using 66.Xr recvfrom 2 ; 67the socket address argument is a 68.Dv "struct sockaddr_ng" 69containing the sender's netgraph address. Conversely, control messages 70can be sent to any node by calling 71.Xr sendto 2 , 72supplying the recipient's address in a 73.Dv "struct sockaddr_ng" . 74The 75.Xr bind 2 76system call may be used to assign a global netgraph name to the node. 77.Pp 78To transmit and receive netgraph data packets, a 79.Dv NG_DATA 80socket must also be created using 81.Xr socket 2 82and associated with a 83.Nm socket 84node. 85.Dv NG_DATA sockets do not automatically 86have nodes associated with them; they are bound to a specific node via the 87.Xr connect 2 88system call. The address argument is the netgraph address of the 89.Nm socket 90node already created. Once a data socket is associated with a node, 91any data packets received by the node are read using 92.Xr recvfrom 2 93and any packets to be sent out from the node are written using 94.Xr sendto 2 . 95In the case of data sockets, the 96.Dv "struct sockaddr_ng" 97contains the name of the 98.Em hook 99on which the data was received or should be sent. 100.Pp 101There is a user library that simplifies using netgraph sockets; see 102.Xr netgraph 3 . 103.Sh HOOKS 104This node type supports hooks with arbitrary names (as long as 105they are unique) and always accepts hook connection requests. 106.Sh CONTROL MESSAGES 107This node type supports only the generic control messages. 108.Sh SHUTDOWN 109This node type shuts down and disappears when both the associated 110.Dv NG_CONTROL 111and 112.Dv NG_DATA 113sockets have been closed, or a 114.Dv NGM_SHUTDOWN 115control message is received. In the latter case, attempts to write 116to the still-open sockets will return 117.Er ENOTCONN . 118.Sh BUGS 119It is not possible to reject the connection of a hook, though any 120data received on that hook can certainly be ignored. 121.Sh SEE ALSO 122.Xr socket 2 , 123.Xr netgraph 3 , 124.Xr netgraph 4 , 125.Xr ngctl 8 . 126.Sh AUTHOR 127Julian Elisher <julian@whistle.com> 128