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.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)getnetent.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd June 4, 1993 32.Dt GETNETENT 3 33.Os 34.Sh NAME 35.Nm getnetent , 36.Nm getnetbyaddr , 37.Nm getnetbyname , 38.Nm setnetent , 39.Nm endnetent 40.Nd get network entry 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In netdb.h 45.Ft struct netent * 46.Fn getnetent void 47.Ft struct netent * 48.Fn getnetbyname "const char *name" 49.Ft struct netent * 50.Fn getnetbyaddr "uint32_t net" "int type" 51.Ft void 52.Fn setnetent "int stayopen" 53.Ft void 54.Fn endnetent void 55.Sh DESCRIPTION 56The 57.Fn getnetent , 58.Fn getnetbyname , 59and 60.Fn getnetbyaddr 61functions 62each return a pointer to an object with the 63following structure describing an internet network. 64This structure contains either the information obtained 65from the nameserver, 66.Xr named 8 , 67broken-out fields of a line in the network data base 68.Pa /etc/networks , 69or entries supplied by the 70.Xr yp 8 71system. 72The order of the lookups is controlled by the 73`networks' entry in 74.Xr nsswitch.conf 5 . 75.Bd -literal -offset indent 76struct netent { 77 char *n_name; /* official name of net */ 78 char **n_aliases; /* alias list */ 79 int n_addrtype; /* net number type */ 80 uint32_t n_net; /* net number */ 81}; 82.Ed 83.Pp 84The members of this structure are: 85.Bl -tag -width n_addrtype 86.It Fa n_name 87The official name of the network. 88.It Fa n_aliases 89A zero terminated list of alternate names for the network. 90.It Fa n_addrtype 91The type of the network number returned; currently only AF_INET. 92.It Fa n_net 93The network number. 94Network numbers are returned in machine byte 95order. 96.El 97.Pp 98The 99.Fn getnetent 100function 101reads the next line of the file, opening the file if necessary. 102.Pp 103The 104.Fn setnetent 105function 106opens and rewinds the file. 107If the 108.Fa stayopen 109flag is non-zero, 110the net data base will not be closed after each call to 111.Fn getnetbyname 112or 113.Fn getnetbyaddr . 114.Pp 115The 116.Fn endnetent 117function 118closes the file. 119.Pp 120The 121.Fn getnetbyname 122function 123and 124.Fn getnetbyaddr 125sequentially search from the beginning 126of the file until a matching 127net name or 128net address and type is found, 129or until 130.Dv EOF 131is encountered. 132The 133.Fa type 134argument 135must be 136.Dv AF_INET . 137Network numbers are supplied in host order. 138.Sh FILES 139.Bl -tag -width /etc/nsswitch.conf -compact 140.It Pa /etc/networks 141.It Pa /etc/nsswitch.conf 142.It Pa /etc/resolv.conf 143.El 144.Sh DIAGNOSTICS 145Null pointer returned on 146.Dv EOF 147or error. 148.Sh SEE ALSO 149.Xr networks 5 150.Pp 151.%T RFC 1101 152.Sh HISTORY 153The 154.Fn getnetent , 155.Fn getnetbyaddr , 156.Fn getnetbyname , 157.Fn setnetent , 158and 159.Fn endnetent 160functions appeared in 161.Bx 4.2 . 162.Sh BUGS 163The data space used by 164these functions is thread-specific; if future use requires the data, it should be 165copied before any subsequent calls to these functions overwrite it. 166Only Internet network 167numbers are currently understood. 168Expecting network numbers to fit 169in no more than 32 bits is probably 170naive. 171