1.\" Copyright (c) 1990, 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.\" @(#)sliplogin.8 8.2 (Berkeley) 1/5/94 33.\" $FreeBSD: src/usr.sbin/sliplogin/sliplogin.8,v 1.12.2.5 2003/03/11 22:31:33 trhodes Exp $ 34.\" $DragonFly: src/usr.sbin/sliplogin/sliplogin.8,v 1.2 2003/06/17 04:30:03 dillon Exp $ 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 Op Ar device 45.Sh DESCRIPTION 46The 47.Nm 48utility is used to turn the terminal line on standard input (or 49.Ar device ) 50into a Serial Line IP 51.Pq Tn SLIP 52link to a remote host. To do this, the program 53searches the file 54.Pa /etc/sliphome/slip.hosts 55for an entry matching 56.Ar loginname 57(which defaults to the current login name if omitted). 58If a matching entry is found, the line is configured appropriately 59for slip (8-bit transparent i/o) and converted to 60.Tn SLIP 61line discipline using the optional line discipline parameters. 62.Pp 63The optional line discipline parameters consist of one or more of 64the following; 65.Sq normal , 66.Sq compress , 67.Sq noicmp , 68or 69.Sq autocomp 70which correspond respectively to 71.Sq use normal line discipline 72(no header compression), 73.Sq enable VJ header compression , 74.Sq throw away ICMP packets , 75and 76.Sq auto enable VJ header compression 77(only if the remote end of the link also supports it). 78.Pp 79Then a shell script is invoked to initialize the slip 80interface with the appropriate local and remote 81.Tn IP 82address, 83netmask, etc. 84.Pp 85The usual initialization script is 86.Pa /etc/sliphome/slip.login 87but, if particular hosts need special initialization, the file 88.Pa /etc/sliphome/slip.login. Ns Ar loginname 89will be executed instead if it exists. 90The script is invoked with the parameters 91.Bl -tag -width slipunit 92.It Em slipunit 93The unit number of the slip interface assigned to this line. E.g., 94.Sy 0 95for 96.Sy sl0 . 97.It Em speed 98The speed of the line. 99.It Em args 100The arguments from the 101.Pa /etc/sliphome/slip.hosts 102entry, in order starting with 103.Ar loginname . 104.El 105.Pp 106Only the super-user may attach a network interface. The interface is 107automatically detached when the other end hangs up or the 108.Nm 109process dies. If the kernel slip 110module has been configured for it, all routes through that interface will 111also disappear at the same time. If there is other processing a site 112would like done on hangup, the file 113.Pa /etc/sliphome/slip.logout 114or 115.Pa /etc/sliphome/slip.logout. Ns Ar loginname 116is executed if it exists. It is given the same arguments as the login script. 117.Ss Format of /etc/sliphome/slip.hosts 118Comments (lines starting with a `#') and blank lines (or started 119with space) are ignored. 120Other lines must start with a 121.Ar loginname 122but the remaining arguments can be whatever is appropriate for the 123.Pa slip.login 124file that will be executed for that name. 125Arguments are separated by white space and follow normal 126.Xr sh 1 127quoting conventions (however, 128.Ar loginname 129cannot be quoted). 130Usually, lines have the form 131.Bd -literal -offset indent 132loginname local-address remote-address netmask opt-args 133.Ed 134.Pp 135where 136.Em local-address 137and 138.Em remote-address 139are the IP host names or addresses of the local and remote ends of the 140slip line and 141.Em netmask 142is the appropriate IP netmask. These arguments are passed 143directly to 144.Xr ifconfig 8 . 145.Em Opt-args 146are optional arguments used to configure the line. 147.Sh FreeBSD Additions 148An additional SLIP configuration file (if present) is 149.Pa /etc/sliphome/slip.slparms . 150If particular hosts need different configurations, the file 151.Pa /etc/sliphome/slip.slparms. Ns Ar loginname 152will be parsed instead if it exists. 153.Ss Format of /etc/sliphome/slip.slparms* 154Comments (lines starting with a `#') and blank lines (or started with 155space) are ignored. 156This file contains from one to three numeric parameters separated with spaces, 157in order: 158.Ar keepalive , 159.Ar outfill 160and 161.Ar slunit . 162.Bl -tag -width keepalive 163.It Ar keepalive 164Set SLIP "keep alive" timeout in seconds. 165If FRAME_END is not received in 166this amount of time, 167.Nm 168closes the line and exits. 169The default value is no timeout (zero). 170.It Ar outfill 171Set SLIP "out fill" timeout in seconds. 172It forces at least one FRAME_END 173to be sent during this time period, which is necessary for the "keep alive" 174timeout on the remote side. 175The default value is no timeout (zero). 176.It Ar slunit 177Set the SLIP unit number directly. 178Use with caution, because no check is made 179for two interfaces with same number. 180By default sliplogin dynamically assigns the unit number. 181.El 182.Pp 183If latter two parameters are omitted, they will not affect the 184corresponding SLIP configuration. 185If any of first two parameters is equal to zero, it will not affect 186the corresponding SLIP configuration. 187.Sh EXAMPLES 188The normal use of 189.Nm 190is to create a 191.Pa /etc/passwd 192entry for each legal, remote slip site with 193.Nm 194as the shell for that entry. E.g., 195.Bd -literal 196Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin 197.Ed 198.Pp 199(Our convention is to name the account used by remote host 200.Ar hostname 201as 202.Em Shostname . ) 203Then an entry is added to 204.Pa slip.hosts 205that looks like: 206.Pp 207.Bd -literal -offset indent -compact 208Sfoo `hostname` foo netmask 209.Ed 210.Pp 211where 212.Em `hostname` 213will be evaluated by 214.Xr sh 215to the local host name and 216.Em netmask 217is the local host IP netmask. 218.Pp 219Note that 220.Nm 221must be setuid to root and, while not a security hole, moral defectives 222can use it to place terminal lines in an unusable state and/or deny 223access to legitimate users of a remote slip line. To prevent this, 224.Nm 225is installed as user 226.Em root , 227group 228.Em network 229and mode 4550 so that only members of group 230.Em network 231may run 232.Nm . 233The system administrator should make sure that all legitimate users 234are a member of the correct group. 235.Sh DIAGNOSTICS 236The 237.Nm 238utility logs various information to the system log daemon, 239.Xr syslogd 8 , 240with a facility code of 241.Em daemon . 242The messages are listed here, grouped by severity level. 243.Pp 244.Sy Error Severity 245.Bl -tag -width Ds -compact 246.It Sy ioctl (TCGETS): Em reason 247A 248.Dv TCGETS 249.Fn ioctl 250to get the line parameters failed. 251.Pp 252.It Sy ioctl (TCSETS): Em reason 253A 254.Dv TCSETS 255.Fn ioctl 256to set the line parameters failed. 257.Pp 258.It Sy /etc/sliphome/slip.hosts: Em reason 259The 260.Pa /etc/sliphome/slip.hosts 261file could not be opened. 262.Pp 263.It Sy access denied for Em user 264No entry for 265.Em user 266was found in 267.Pa /etc/sliphome/slip.hosts . 268.El 269.Pp 270.Sy Notice Severity 271.Bl -tag -width Ds -compact 272.It Sy "attaching slip unit" Em unit Sy for Ar loginname 273.Tn SLIP 274unit 275.Em unit 276was successfully attached. 277.El 278.Sh FILES 279.Bl -tag -width indent 280.It Pa /etc/sliphome/slip.hosts 281list of host login names and parameters. 282.It Pa /etc/sliphome/slip.login 283script executed when a connection is made. 284.It Pa /etc/sliphome/slip.login. Ns Ar loginname 285script executed when a connection is made by 286.Ar loginname . 287.It Pa /etc/sliphome/slip.logout 288script executed when a connection is lost. 289.It Pa /etc/sliphome/slip.logout. Ns Ar loginname 290script executed when a connection is lost by 291.Ar loginname . 292.It Pa /etc/sliphome/slip.slparms 293extra parameters file. 294.It Pa /etc/sliphome/slip.slparms. Ns Ar loginname 295extra parameters file for 296.Ar loginname . 297.It Pa /var/run/ Ns Ar ttyXn Ns Pa .if 298contains the name of the network interface used by the sliplogin process on 299.Ar ttyXn . 300.It Pa /var/run/ Ns Ar slX Ns Pa .pid 301contains the PID of the sliplogin process which is using interface 302.Ar slX . 303.El 304.Sh SEE ALSO 305.Xr slattach 8 , 306.Xr syslogd 8 307.Pp 308.Pa /usr/share/examples/sliplogin 309.Sh HISTORY 310The 311.Nm 312utility appeared in 313.Bx 4.3 Reno . 314