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 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.In 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 "uint32_t 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 8 75system. 76The order of the lookups is controlled by the 77`networks' entry in 78.Xr nsswitch.conf 5 . 79.Pp 80.Bd -literal -offset indent 81struct netent { 82 char *n_name; /* official name of net */ 83 char **n_aliases; /* alias list */ 84 int n_addrtype; /* net number type */ 85 uint32_t n_net; /* net number */ 86}; 87.Ed 88.Pp 89The members of this structure are: 90.Bl -tag -width n_addrtype 91.It Fa n_name 92The official name of the network. 93.It Fa n_aliases 94A zero terminated list of alternate names for the network. 95.It Fa n_addrtype 96The type of the network number returned; currently only AF_INET. 97.It Fa n_net 98The network number. 99Network numbers are returned in machine byte 100order. 101.El 102.Pp 103The 104.Fn getnetent 105function 106reads the next line of the file, opening the file if necessary. 107.Pp 108The 109.Fn setnetent 110function 111opens and rewinds the file. 112If the 113.Fa stayopen 114flag is non-zero, 115the net data base will not be closed after each call to 116.Fn getnetbyname 117or 118.Fn getnetbyaddr . 119.Pp 120The 121.Fn endnetent 122function 123closes the file. 124.Pp 125The 126.Fn getnetbyname 127function 128and 129.Fn getnetbyaddr 130sequentially search from the beginning 131of the file until a matching 132net name or 133net address and type is found, 134or until 135.Dv EOF 136is encountered. 137The 138.Fa type 139argument 140must be 141.Dv AF_INET . 142Network numbers are supplied in host order. 143.Sh FILES 144.Bl -tag -width /etc/nsswitch.conf -compact 145.It Pa /etc/networks 146.It Pa /etc/nsswitch.conf 147.It Pa /etc/resolv.conf 148.El 149.Sh DIAGNOSTICS 150Null pointer 151(0) returned on 152.Dv EOF 153or error. 154.Sh SEE ALSO 155.Xr networks 5 156.Pp 157.%T RFC 1101 158.Sh HISTORY 159The 160.Fn getnetent , 161.Fn getnetbyaddr , 162.Fn getnetbyname , 163.Fn setnetent , 164and 165.Fn endnetent 166functions appeared in 167.Bx 4.2 . 168.Sh BUGS 169The data space used by 170these functions is thread-specific; if future use requires the data, it should be 171copied before any subsequent calls to these functions overwrite it. 172Only Internet network 173numbers are currently understood. 174Expecting network numbers to fit 175in no more than 32 bits is probably 176naive. 177