Annotation of 43BSDReno/usr.sbin/sliplogin/sliplogin.8, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1990 The Regents of the University of California.
                      2: .\" All rights reserved.
                      3: .\"
                      4: .\" Redistribution and use in source and binary forms are permitted provided
                      5: .\" that: (1) source distributions retain this entire copyright notice and
                      6: .\" comment, and (2) distributions including binaries display the following
                      7: .\" acknowledgement:  ``This product includes software developed by the
                      8: .\" University of California, Berkeley and its contributors'' in the
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                     11: .\" Neither the name of the University nor the names of its contributors may
                     12: .\" be used to endorse or promote products derived from this software without
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                     14: .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
                     15: .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
                     16: .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     17: .\"
                     18: .\"    @(#)sliplogin.8 5.2 (Berkeley) 7/1/90
                     19: .\"
                     20: .TH SLIPLOGIN 8 "July 1, 1990"
                     21: .SH NAME
                     22: sliplogin \- attach a serial line network interface
                     23: .SH SYNOPSIS
                     24: .B sliplogin
                     25: [
                     26: .I loginname
                     27: ]
                     28: .SH DESCRIPTION
                     29: .B sliplogin
                     30: is used to turn the terminal line on standard input into
                     31: a Serial Line IP (SLIP) link to a remote host.  To do this, the program
                     32: searches the file
                     33: .B /etc/slip.hosts
                     34: for an entry matching
                     35: .I loginname
                     36: (which defaults to the current login name if omitted).
                     37: If a matching entry is found, the line is configured appropriately
                     38: for slip (8-bit transparent i/o) and converted to SLIP line
                     39: discipline.  Then a shell script is invoked to initialize the slip
                     40: interface with the appropriate local and remote IP address,
                     41: netmask, etc.
                     42: .PP
                     43: The usual initialization script is
                     44: .B /etc/slip.login
                     45: but, if particular hosts need special initialization, the file
                     46: .BI /etc/slip.login. loginname
                     47: will be executed instead if it exists.
                     48: The script is invoked with the parameters
                     49: .TP
                     50: .I slipunit
                     51: The unit number of the slip interface assigned to this line.  E.g.,
                     52: .B 0
                     53: for
                     54: .BR sl0 .
                     55: .TP
                     56: .I speed
                     57: The speed of the line.
                     58: .TP
                     59: .I args
                     60: The arguments from the
                     61: .B /etc/slip.hosts
                     62: entry, in order starting with
                     63: .IR loginname .
                     64: .PP
                     65: Only the super-user may attach a network interface.  The interface is
                     66: automatically detached when the other end hangs up or the
                     67: .B sliplogin
                     68: process dies.  If the kernel slip
                     69: module has been configured for it, all routes through that interface will
                     70: also disappear at the same time.  If there is other processing a site
                     71: would like done on hangup, the file
                     72: .B /etc/slip.logout
                     73: or
                     74: .BI /etc/slip.logout. loginname
                     75: is executed if it exists.  It is given the same arguments as the login script.
                     76: .SS Format of /etc/slip.hosts
                     77: Comments (lines starting with a `#') and blank lines are ignored.
                     78: Other lines must start with a
                     79: .I loginname
                     80: but the remaining arguments can be whatever is appropriate for the
                     81: .B slip.login
                     82: file that will be executed for that name.
                     83: Arguments are separated by white space and follow normal
                     84: .BR sh (1)
                     85: quoting conventions (however,
                     86: .I loginname
                     87: cannot be quoted).
                     88: Usually, lines have the form
                     89: .RS
                     90: .I
                     91: loginname local-address remote-address netmask opt-args
                     92: .RE
                     93: where
                     94: .I local-address
                     95: and
                     96: .I remote-address
                     97: are the IP host names or addresses of the local and remote ends of the
                     98: slip line and
                     99: .I netmask
                    100: is the appropriate IP netmask.  These arguments are passed
                    101: directly to
                    102: .BR ifconfig (8).
                    103: .I Opt-args
                    104: are optional arguments used to configure the line.
                    105: .SH EXAMPLE
                    106: The normal use of
                    107: .B sliplogin
                    108: is to create a
                    109: .B /etc/passwd
                    110: entry for each legal, remote slip site with
                    111: .B sliplogin
                    112: as the shell for that entry.  E.g.,
                    113: .RS
                    114: Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/etc/sliplogin
                    115: .RE
                    116: (Our convention is to name the account used by remote host
                    117: .I hostname
                    118: as
                    119: .IR Shostname .)
                    120: Then an entry is added to
                    121: .B slip.hosts
                    122: that looks like:
                    123: .RS
                    124: Sfoo   `hostname`      foo     netmask
                    125: .RE
                    126: where
                    127: .I `hostname`
                    128: will be evaluated by
                    129: .B sh
                    130: to the local host name and
                    131: .I netmask
                    132: is the local host IP netmask.
                    133: .PP
                    134: Note that
                    135: .B sliplogin
                    136: must be setuid to root and, while not a security hole, moral defectives
                    137: can use it to place terminal lines in an unusable state and/or deny
                    138: access to legitimate users of a remote slip line.  To prevent this,
                    139: a site can create a group, say
                    140: .IR slip ,
                    141: that only the slip login accounts are put in then make sure that
                    142: .B /etc/sliplogin
                    143: is in group
                    144: .I slip
                    145: and mode 4550 (setuid root, only group
                    146: .I slip
                    147: can execute binary).
                    148: .SH "DIAGNOSTICS"
                    149: .B sliplogin
                    150: logs various information to the system log daemon,
                    151: .BR syslogd (8),
                    152: with a facility code of
                    153: .BR daemon .
                    154: The messages are listed here, grouped by severity level.
                    155: .SS Err Severity
                    156: .TP
                    157: .BI "ioctl (TCGETS): " reason
                    158: A
                    159: .SB TCGETS
                    160: .B ioctl
                    161: to get the line parameters failed.
                    162: .TP
                    163: .BI "ioctl (TCSETS): " reason
                    164: A
                    165: .SB TCSETS
                    166: .B ioctl
                    167: to set the line parameters failed.
                    168: .TP
                    169: .BI "/etc/slip.hosts: " reason
                    170: The
                    171: .B /etc/slip.hosts
                    172: file could not be opened.
                    173: .TP
                    174: .BI "access denied for " user
                    175: No entry for
                    176: .I user
                    177: was found in
                    178: .BR /etc/slip.hosts .
                    179: .SS Notice Severity
                    180: .TP
                    181: .BI "attaching slip unit " unit " for " loginname
                    182: SLIP unit
                    183: .I unit
                    184: was successfully attached.
                    185: .SH "SEE ALSO"
                    186: .BR slattach (8),
                    187: .BR syslogd (8)

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