133
143
using TLS with an OpenPGP key to ensure authenticity and
134
144
confidentiality. This client program keeps running, trying all
135
145
servers on the network, until it receives a satisfactory reply
136
or a TERM signal is received. If no servers are found, or after
137
all servers have been tried, it waits indefinitely for new
146
or a TERM signal. After all servers have been tried, all
147
servers are periodically retried. If no servers are found it
148
will wait indefinitely for new servers to appear.
151
The network interface is selected like this: If an interface is
152
specified using the <option>--interface</option> option, that
153
interface is used. Otherwise, <command>&COMMANDNAME;</command>
154
will choose any interface that is up and running and is not a
155
loopback interface, is not a point-to-point interface, is
156
capable of broadcasting and does not have the NOARP flag (see
157
<citerefentry><refentrytitle>netdevice</refentrytitle>
158
<manvolnum>7</manvolnum></citerefentry>). (If the
159
<option>--connect</option> option is used, point-to-point
160
interfaces and non-broadcast interfaces are accepted.) If no
161
acceptable interfaces are found, re-run the check but without
162
the <quote>up and running</quote> requirement, and manually take
163
the selected interface up (and later take it down on program
167
Before a network interface is selected, all <quote>network
168
hooks</quote> are run; see <xref linkend="network-hooks"/>.
141
171
This program is not meant to be run directly; it is really meant
448
<refsect1 id="network-hooks">
449
<title>NETWORK HOOKS</title>
451
If a network interface like a bridge or tunnel is required to
452
find a Mandos server, this requires the interface to be up and
453
running before <command>&COMMANDNAME;</command> starts looking
454
for Mandos servers. This can be accomplished by creating a
455
<quote>network hook</quote> program, and placing it in a special
459
Before the network is used (and again before program exit), any
460
runnable programs found in the network hook directory are run
461
with the argument <quote><literal>start</literal></quote> or
462
<quote><literal>stop</literal></quote>. This should bring up or
463
down, respectively, any network interface which
464
<command>&COMMANDNAME;</command> should use.
466
<refsect2 id="hook-requirements">
467
<title>REQUIREMENTS</title>
469
A network hook must be an executable file, and its name must
470
consist entirely of upper and lower case letters, digits,
471
underscores, periods, and hyphens.
474
A network hook will receive one argument, which can be one of
479
<term><literal>start</literal></term>
482
This should make the network hook create (if necessary)
483
and bring up a network interface.
488
<term><literal>stop</literal></term>
491
This should make the network hook take down a network
492
interface, and delete it if it did not exist previously.
497
<term><literal>files</literal></term>
500
This should make the network hook print, <emphasis>one
501
file per line</emphasis>, all the files needed for it to
502
run. (These files will be copied into the initial RAM
503
filesystem.) Typical use is for a network hook which is
504
a shell script to print its needed binaries.
507
It is not necessary to print any non-executable files
508
already in the network hook directory, these will be
509
copied implicitly if they otherwise satisfy the name
515
<term><literal>modules</literal></term>
518
This should make the network hook print, <emphasis>on
519
separate lines</emphasis>, all the kernel modules needed
520
for it to run. (These modules will be copied into the
521
initial RAM filesystem.) For instance, a tunnel
523
<quote><literal>tun</literal></quote> module.
529
The network hook will be provided with a number of environment
534
<term><envar>MANDOSNETHOOKDIR</envar></term>
537
The network hook directory, specified to
538
<command>&COMMANDNAME;</command> by the
539
<option>--network-hook-dir</option> option. Note: this
540
should <emphasis>always</emphasis> be used by the
541
network hook to refer to itself or any files in the hook
542
directory it may require.
547
<term><envar>DEVICE</envar></term>
550
The network interface, as specified to
551
<command>&COMMANDNAME;</command> by the
552
<option>--interface</option> option. If this is not the
553
interface a hook will bring up, there is no reason for a
559
<term><envar>MODE</envar></term>
562
This will be the same as the first argument;
563
i.e. <quote><literal>start</literal></quote>,
564
<quote><literal>stop</literal></quote>,
565
<quote><literal>files</literal></quote>, or
566
<quote><literal>modules</literal></quote>.
571
<term><envar>VERBOSITY</envar></term>
574
This will be the <quote><literal>1</literal></quote> if
575
the <option>--debug</option> option is passed to
576
<command>&COMMANDNAME;</command>, otherwise
577
<quote><literal>0</literal></quote>.
582
<term><envar>DELAY</envar></term>
585
This will be the same as the <option>--delay</option>
586
option passed to <command>&COMMANDNAME;</command>.
592
A hook may not read from standard input, and should be
593
restrictive in printing to standard output or standard error
594
unless <varname>VERBOSITY</varname> is
595
<quote><literal>1</literal></quote>.
390
600
<refsect1 id="files">
391
601
<title>FILES</title>