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.Pp 76.Bd -literal -offset indent 77struct netent { 78 char *n_name; /* official name of net */ 79 char **n_aliases; /* alias list */ 80 int n_addrtype; /* net number type */ 81 uint32_t n_net; /* net number */ 82}; 83.Ed 84.Pp 85The members of this structure are: 86.Bl -tag -width n_addrtype 87.It Fa n_name 88The official name of the network. 89.It Fa n_aliases 90A zero terminated list of alternate names for the network. 91.It Fa n_addrtype 92The type of the network number returned; currently only AF_INET. 93.It Fa n_net 94The network number. 95Network numbers are returned in machine byte 96order. 97.El 98.Pp 99The 100.Fn getnetent 101function 102reads the next line of the file, opening the file if necessary. 103.Pp 104The 105.Fn setnetent 106function 107opens and rewinds the file. 108If the 109.Fa stayopen 110flag is non-zero, 111the net data base will not be closed after each call to 112.Fn getnetbyname 113or 114.Fn getnetbyaddr . 115.Pp 116The 117.Fn endnetent 118function 119closes the file. 120.Pp 121The 122.Fn getnetbyname 123function 124and 125.Fn getnetbyaddr 126sequentially search from the beginning 127of the file until a matching 128net name or 129net address and type is found, 130or until 131.Dv EOF 132is encountered. 133The 134.Fa type 135argument 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 thread-specific; 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