1.\" $NetBSD: sliplogin.8,v 1.8 2002/02/02 01:51:20 wiz Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)sliplogin.8 8.2 (Berkeley) 1/5/94 35.\" 36.Dd January 5, 1994 37.Dt SLIPLOGIN 8 38.Os 39.Sh NAME 40.Nm sliplogin 41.Nd attach a serial line network interface 42.Sh SYNOPSIS 43.Nm 44.Op Ar loginname 45.Sh DESCRIPTION 46.Nm 47is used to turn the terminal line on standard input into 48a Serial Line IP 49.Pq Tn SLIP 50link to a remote host. To do this, the program 51searches the file 52.Pa /etc/sliphome/slip.hosts 53for an entry matching 54.Ar loginname 55(which defaults to the current login name if omitted). 56If a matching entry is found, the line is configured appropriately 57for slip (8-bit transparent i/o) and converted to 58.Tn SLIP 59line 60discipline. Then a shell script is invoked to initialize the slip 61interface with the appropriate local and remote 62.Tn IP 63address, 64netmask, etc. 65.Pp 66The usual initialization script is 67.Pa /etc/sliphome/slip.login 68but, if particular hosts need special initialization, the file 69.Pa /etc/sliphome/slip.login. Ns Ar loginname 70will be executed instead if it exists. 71The script is invoked with the parameters 72.Bl -tag -width slipunit 73.It Em slipunit 74The unit number of the slip interface assigned to this line. E.g., 75.Sy 0 76for 77.Sy sl0 . 78.It Em speed 79The speed of the line. 80.It Em args 81The arguments from the 82.Pa /etc/sliphome/slip.hosts 83entry, in order starting with 84.Ar loginname . 85.El 86.Pp 87Only the super-user may attach a network interface. The interface is 88automatically detached when the other end hangs up or the 89.Nm 90process dies. If the kernel slip 91module has been configured for it, all routes through that interface will 92also disappear at the same time. If there is other processing a site 93would like done on hangup, the file 94.Pa /etc/sliphome/slip.logout 95or 96.Pa /etc/sliphome/slip.logout. Ns Ar loginname 97is executed if it exists. It is given the same arguments as the login script. 98.Ss Format of /etc/sliphome/slip.hosts 99Comments (lines starting with a `#') and blank lines are ignored. 100Other lines must start with a 101.Ar loginname 102but the remaining arguments can be whatever is appropriate for the 103.Pa slip.login 104file that will be executed for that name. 105Arguments are separated by white space and follow normal 106.Xr sh 1 107quoting conventions (however, 108.Ar loginname 109cannot be quoted). 110Usually, lines have the form 111.Bd -literal -offset indent 112loginname local-address remote-address netmask opt-args 113.Ed 114.Pp 115where 116.Em local-address 117and 118.Em remote-address 119are the IP host names or addresses of the local and remote ends of the 120slip line and 121.Em netmask 122is the appropriate IP netmask. These arguments are passed 123directly to 124.Xr ifconfig 8 . 125.Em opt-args 126are optional arguments used to configure the line. 127.Sh EXAMPLES 128The normal use of 129.Nm 130is to create a 131.Pa /etc/passwd 132entry for each legal, remote slip site with 133.Nm 134as the shell for that entry. E.g., 135.Bd -literal 136Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin 137.Ed 138.Pp 139(Our convention is to name the account used by remote host 140.Ar hostname 141as 142.Em Shostname . ) 143Then an entry is added to 144.Pa slip.hosts 145that looks like: 146.Pp 147.Bd -literal -offset indent -compact 148Sfoo `hostname` foo netmask 149.Ed 150.Pp 151where 152.Em `hostname` 153will be evaluated by 154.Xr sh 1 155to the local host name and 156.Em netmask 157is the local host IP netmask. 158.Pp 159Note that 160.Nm 161must be setuid to root and, while not a security hole, moral defectives 162can use it to place terminal lines in an unusable state and/or deny 163access to legitimate users of a remote slip line. To prevent this, 164a site can create a group, say 165.Em slip , 166that only the slip login accounts are put in then make sure that 167.Pa /usr/sbin/sliplogin 168is in group 169.Em slip 170and mode 4550 (setuid root, only group 171.Em slip 172can execute binary). 173.Sh DIAGNOSTICS 174.Nm 175logs various information to the system log daemon, 176.Xr syslogd 8 , 177with a facility code of 178.Em daemon . 179The messages are listed here, grouped by severity level. 180.Pp 181.Sy Error Severity 182.Bl -tag -width Ds -compact 183.It Sy ioctl (TCGETS): Em reason 184A 185.Dv TCGETS 186.Fn ioctl 187to get the line parameters failed. 188.Pp 189.It Sy ioctl (TCSETS): Em reason 190A 191.Dv TCSETS 192.Fn ioctl 193to set the line parameters failed. 194.Pp 195.It Sy /etc/sliphome/slip.hosts: Em reason 196The 197.Pa /etc/sliphome/slip.hosts 198file could not be opened. 199.Pp 200.It Sy access denied for Em user 201No entry for 202.Em user 203was found in 204.Pa /etc/sliphome/slip.hosts . 205.El 206.Pp 207.Sy Notice Severity 208.Bl -tag -width Ds -compact 209.It Sy "attaching slip unit" Em unit Sy for Ar loginname 210.Tn SLIP 211unit 212.Em unit 213was successfully attached. 214.El 215.Sh SEE ALSO 216.Xr sl 4 , 217.Xr slattach 8 , 218.Xr syslogd 8 219.Sh HISTORY 220The 221.Nm 222command 223.Bt 224