1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)getnetent.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt GETNETENT 3 37.Os BSD 4.2 38.Sh NAME 39.Nm getnetent , 40.Nm getnetbyaddr , 41.Nm getnetbyname , 42.Nm setnetent , 43.Nm endnetent 44.Nd get network entry 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.Fd #include <netdb.h> 49.Ft struct netent * 50.Fn getnetent void 51.Ft struct netent * 52.Fn getnetbyname "const char *name" 53.Ft struct netent * 54.Fn getnetbyaddr "unsigned long net" "int type" 55.Ft void 56.Fn setnetent "int stayopen" 57.Ft void 58.Fn endnetent void 59.Sh DESCRIPTION 60The 61.Fn getnetent , 62.Fn getnetbyname , 63and 64.Fn getnetbyaddr 65functions 66each return a pointer to an object with the 67following structure describing an internet network. 68This structure contains either the information obtained 69from the nameserver, 70.Xr named 8 , 71broken-out fields of a line in the network data base 72.Pa /etc/networks , 73or entries supplied by the 74.Xr yp 4 75system. The order of the lookups is controlled by the 76`networks' entry in 77.Xr nsswitch.conf 5 . 78.Pp 79.Bd -literal -offset indent 80struct netent { 81 char *n_name; /* official name of net */ 82 char **n_aliases; /* alias list */ 83 int n_addrtype; /* net number type */ 84 unsigned long n_net; /* net number */ 85}; 86.Ed 87.Pp 88The members of this structure are: 89.Bl -tag -width n_addrtype 90.It Fa n_name 91The official name of the network. 92.It Fa n_aliases 93A zero terminated list of alternate names for the network. 94.It Fa n_addrtype 95The type of the network number returned; currently only AF_INET. 96.It Fa n_net 97The network number. Network numbers are returned in machine byte 98order. 99.El 100.Pp 101The 102.Fn getnetent 103function 104reads the next line of the file, opening the file if necessary. 105.Pp 106The 107.Fn setnetent 108function 109opens and rewinds the file. If the 110.Fa stayopen 111flag is non-zero, 112the net data base will not be closed after each call to 113.Fn getnetbyname 114or 115.Fn getnetbyaddr . 116.Pp 117The 118.Fn endnetent 119function 120closes the file. 121.Pp 122The 123.Fn getnetbyname 124function 125and 126.Fn getnetbyaddr 127sequentially search from the beginning 128of the file until a matching 129net name or 130net address and type is found, 131or until 132.Dv EOF 133is encountered. 134The 135.Fa type 136must be 137.Dv AF_INET . 138Network numbers are supplied in host order. 139.Sh FILES 140.Bl -tag -width /etc/nsswitch.conf -compact 141.It Pa /etc/networks 142.It Pa /etc/nsswitch.conf 143.It Pa /etc/resolv.conf 144.El 145.Sh DIAGNOSTICS 146Null pointer 147(0) returned on 148.Dv EOF 149or error. 150.Sh SEE ALSO 151.Xr networks 5 152.Pp 153.%T RFC 1101 154.Sh HISTORY 155The 156.Fn getnetent , 157.Fn getnetbyaddr , 158.Fn getnetbyname , 159.Fn setnetent , 160and 161.Fn endnetent 162functions appeared in 163.Bx 4.2 . 164.Sh BUGS 165The data space used by 166these functions is static; if future use requires the data, it should be 167copied before any subsequent calls to these functions overwrite it. 168Only Internet network 169numbers are currently understood. 170Expecting network numbers to fit 171in no more than 32 bits is probably 172naive. 173