#
# Configuration par defaut d'un *serveur* OpenVPN pour l'accès nomade au réseau
# privé virtuel de l'AUF.
#
# Pour toutes les options en detail : man openvpn
#

#
# NE PAS MODIFIER CE FICHIER ! Si vous pensez qu'une modification est
# indispensable, contactez d'abord thomas.noel@auf.org pour en parler.
#



# Configuration locale à cette implantation

# --config
#   Load additional config options from file where each line corresponds to one
#   command line option, but with the leading '--' removed.
# AUF RPV : fichier de configuration local (adresses IP du serveur et push vers
# le client) généré lors de l'installation de auf-rpv
config /etc/openvpn/server-nomad.conf.local



# Configuration générale à tous les serveurs RPV2 de l'AUF
# NE PAS MODIFIER... Si vous détectez un soucis, signalez-le à
# thomas.noel@auf.org pour qu'il étudie le problème dans sa globalité.


# Debug et autres


# --verb n
#   Set output verbosity to n (default=1).  Each level shows all info from the
#   previous levels.  Level 3 is recommended if you want a good summary of what’s
#   happening without being swamped by output.
#   0 -- No output except fatal errors.
#   1 to 4 -- Normal usage range.
#   5 -- Output R and W characters to the console for each packet read and
#     write, uppercase is used for TCP/UDP packets and lowercase is used for
#     TUN/TAP packets.
#   6 to 11 -- Debug info range (see errlevel.h for additional information on
#     debug levels).
;verb 1
verb 5

# --syslog [progname]
#   Direct log output to system logger, but do not become a daemon. See
#   --daemon directive above for description of progname parameter.
syslog openvpn/nomad

# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status /var/tmp/openvpn-nomad-status.log


# Mode serveur sur udp/1195, sur un périphérique TUN



# --mode m
#   Set  OpenVPN  major mode.  By default, OpenVPN runs in point-to- point mode
#   ("p2p").  OpenVPN 2.0 introduces a new  mode  ("serv‐ er") which implements
#   a multi-client server capability.
mode server


# --dev tunX | tapX | null
#   TUN/TAP virtual network device ( X can be omitted for a  dynamic device.)
#   tun devices encapsulate IPv4 while tap devices encapsulate ethernet 802.3.
#   You must use either tun devices on both ends of  the  connection or  tap
#   devices on both ends.  You cannot mix them, as they represent different
#   underlying protocols.
# AUF RPV: Creation d'une interface IP virtuelle nommmee "nomad"
dev nomad

# --dev-type device-type
#   Which  device  type  are  we using?  device-type should be tun or tap.  Use
#   this option only if the TUN/TAP device used with  --dev does not begin with
#   tun or tap.
# AUF RPV : l'interface sera une IPv4 virtuelle de type "tun"
dev-type tun

# --persist-tun
#   Don’t close and reopen TUN/TAP  device  or  run  up/down  scripts across
#   SIGUSR1 or --ping-restart restarts.
#   SIGUSR1  is  a restart signal similar to SIGHUP, but which offers
#   finer-grained control over reset options.
persist-tun

# --proto p
#   Use protocol p for communicating with remote host.  p can be udp,
#   tcp-client, or tcp-server.
# AUF RPV : tunnel sur UDP/IP
proto udp

# --port port
#   TCP/UDP  port  number for both local and remote.  The current default of
#   1194 represents the official IANA port number assignment for OpenVPN and
#   has been used since version 2.0-beta17.  Previous versions used port 5000
#   as the default.
# AUF RPV : par defaut se connecter sur le port 1194
port 1194

# --comp-lzo
# Use  fast LZO compression -- may add up to 1 byte per packet for
# incompressible data.
comp-lzo



# Delais pour coupure d'un tunnel


# --inactive n
#   (Experimental) Causes OpenVPN to exit after n seconds of inactivity on the
#   TUN/TAP device.  The time length of inactivity is measured since the last
#   incoming tunnel packet.
# AUF RPV : Fin du tunnel au bout d'une heure d'inactivite
inactive 3600
# AUF RPV : on force l'inactivité à une heure sur les clients qui se connectent
push "inactive 3600"

# --ping n
#   Ping remote over the TCP/UDP control channel if no  packets have been sent
#   for at least n seconds (specify --ping on both peers to cause ping packets
#   to be sent in both  directions since  OpenVPN ping  packets are not echoed
#   like IP ping packets).  When used in one of OpenVPN’s secure modes (where
#   --secret,  --tls-server,  or --tls-client is specified), the ping packet
#   will be cryptographically secure.
#   This option has two intended uses:
#   (1) Compatibility with stateful  firewalls.   The  periodic  ping will
#       ensure  that  a stateful firewall rule which allows OpenVPN UDP packets
#       to pass will not time out.
#   (2) To provide a basis for the remote to test  the  existence  of
#       its peer using the --ping-exit option.
# AUF RPV : Envoie d'un "ping" au correspondant toutes les 10 secondes
ping 10
# AUF RPV : on force sur le client
push "ping 10"

# --ping-exit n
#   Causes  OpenVPN to exit after n seconds pass without reception of a ping or
#   other packet from remote.  This option can be combined with  --inactive,
#   --ping, and --ping-exit to create a two-tiered inactivity disconnect.
#   For example,
#       openvpn [options...] --inactive 3600 --ping 10 --ping-exit 60
#   when used on both peers will cause OpenVPN to exit within 60 seconds  if
#   its peer disconnects, but will exit after one hour if no actual tunnel data
#   is exchanged.
# AUF RPV : Abandon du tunnel si pas de reponse au bout de deux minutes
ping-exit 120
# AUF RPV : on force sur le client à quitter au bout d'une seule minute
push "ping-exit 60"

# NOTE : les 4 ping/ping-exit ci-dessus peuvent aussi s'écrire : 
#keepalive 10 120

# --ping-timer-rem
#   Run the --ping-exit / --ping-restart timer only if we have a remote
#   address.  Use this option if you are starting the daemon in listen  mode
#   (i.e.  without an explicit --remote peer), and you don’t want to start
#   clocking timeouts until a remote  peer  connects.
ping-timer-rem



# Securisation système


# --mlock
#    Disable paging by calling the POSIX mlockall function. Requires that
#    OpenVPN be initially run as root (though OpenVPN can subsequently
#    downgrade its UID using the --user option).
#    Using this option ensures that key material and tunnel data are never
#    written to disk due to virtual memory paging operations which occur under
#    most modern operating systems. It ensures that even if an attacker was
#    able to crack the box running OpenVPN, he would not be able to scan the
#    system swap file to recover previously used ephemeral keys, which are used
#    for a period of time governed by the --reneg options (see below), then are
#    discarded.
#    The downside of using --mlock is that it will reduce the amount of
#    physical memory available to other applications.
#mlock

# --chroot dir
#   Chroot to dir after initialization. --chroot essentially redefines dir as
#   being the top level directory tree (/). OpenVPN will therefore be unable to
#   access any files outside this tree. This can be desirable from a security
#   standpoint.
#   Since the chroot operation is delayed until after initialization, most
#   OpenVPN options that reference files will operate in a pre-chroot context.
#   In many cases, the dir parameter can point to an empty directory, however
#   complications can result when scripts or restarts are executed after the
#   chroot operation.
;chroot /var/lib/openvpn.nomad

# --up cmd
#   Shell  command  to run after successful TUN/TAP device open (pre --user UID
#   change).  The up  script  is  useful  for  specifying route  commands which
#   route IP traffic destined for private sub‐ nets which exist at the other
#   end of the VPN connection into the tunnel.
# AUF RPV : ce script desactive les rp_filter sur l'interface TUN et créée
# la prison chroot
;up /etc/openvpn/scripts/up-server
# AUF RPV : Variable d'environnement pour emplacement de la prison (utilisé par
# le script "up-server")
;setenv chroot_jail /var/lib/openvpn.nomad



# --user user
#   Change the user ID of the OpenVPN process to user after initial‐ ization,
#   dropping privileges in the  process.   This  option  is useful to protect
#   the system in the event that some hostile par‐ ty was able to gain control
#   of an OpenVPN session.  Though Open‐ VPN’s  security features make this
#   unlikely, it is provided as a second line of defense.
# AUF RPV : l'utilisateur "openvpn" a des droits spéciaux
# FIXME : est-ce nécessaire pour le serveur nomade ?
;user openvpn
user nobody
# --group group
#   Similar  to  the --user option, this option changes the group ID of the
#   OpenVPN process to group after initialization.
# AUF RPV : le groupe "openvpn" a des droits spéciaux
# FIXME : est-ce nécessaire pour le serveur nomade ?
;group openvpn
group nogroup



# Adressage des clients

# --ifconfig-pool-persist file [seconds]
#   Persist/unpersist ifconfig-pool data to file, at seconds intervals
#   (default=600), as well as on program startup and shutdown.
#   The goal of this option is to provide a long-term association between
#   clients (denoted by their common name) and the virtual IP address assigned
#   to them from the ifconfig-pool. Maintaining a long-term association is good
#   for clients because it allows them to effectively use the --persist-tun
#   option.
#   file is a comma-delimited ASCII file, formatted as <Common-Name>,<IP-address>.
#   If seconds = 0, file will be treated as read-only. This is useful if you
#   would like to treat file as a configuration file.
#   Note that the entries in this file are treated by OpenVPN as suggestions
#   only, based on past associations between a common name and IP address. They
#   do not guarantee that the given common name will always receive the given
#   IP address. If you want guaranteed assignment, use --ifconfig-push
# AUF RPV : Tant que la prison n'est pas refaite à chaque reboot, c'est utile.
ifconfig-pool-persist /var/tmp/openvpn-server.leases 60



# Connexion d'un client : routage

push "route 10.0.0.0 255.0.0.0"

# Config particulieres : non utilisees pour l'instant, les bidouilles
# on verra si on en a besoin plus tard...
client-config-dir /etc/openvpn/ccd

# --tmp-dir dir
#   Specify a directory dir for temporary files. This directory will be used by
#   --client-connect scripts to dynamically generate client-specific
#   configuration files.
tmp-dir /tmp



# Authentification forte (TLS)

# --tls-server
#   Enable TLS and assume server role during TLS handshake.  Note that OpenVPN
#   is designed as a  peer-to-peer application.  The designation of client or
#   server is only for the purpose of negotiating the TLS control channel.
tls-server

# --ca file
#   Certificate authority (CA) file in .pem format, also referred to as the
#   root certificate.  This file can have  multiple  certifi‐ cates  in .pem
#   format, concatenated together.
# AUF RPV : concaténation des certif de toutes les CA, automatiquement et
# périodiquement généré par "get-capath"
ca /etc/openvpn/ssl/all-ca.crt

# --cert file
#   Local peer’s signed certificate in .pem format -- must be signed by  a
#   certificate  authority whose certificate is in --ca file.
# AUF RPV: certificat fourni par le paquet de configuration local
cert /etc/openvpn/ssl/server.crt

# --key file
#   Local  peer’s  private  key in .pem format.  Use the private key which was
#   generated when you built your peer’s certificate  (see -cert file above).
# AUF RPV: clé fournie par le paquet de configuration local
key /etc/openvpn/ssl/server.key

# --persist-key
#   Don’t re-read key files across SIGUSR1 or --ping-restart.
#
#   This option can be combined with --user nobody to allow restarts triggered
#   by the SIGUSR1 signal.   Normally  if  you  drop  root privileges  in
#   OpenVPN, the daemon cannot be restarted since it will now be unable to
#   re-read protected key files.
#   This option solves the problem by persisting keys across SIGUSR1 resets, so
#   they don’t need to be re-read.
# AUF RPV: Pas de relecture des cles en cours d'execution (permet de ne pas mettre
# la clé dans le chroot, par exemple...)
persist-key

# --tls-verify cmd
#    Execute  shell  command cmd to verify the X509 name of a pending TLS
#    connection that has otherwise passed all other tests of cer‐ tification.
#    cmd  should return 0 to allow the TLS handshake to proceed, or 1 to fail.
#    cmd is executed as
#          cmd certificate_depth X509_NAME_oneline
# AUF RPV : ce script verifie le format du CN et la validité du certificat
# envoyé (notamment la révocation) via --tls-export-cert (cf ci-dessous)
;tls-verify /etc/openvpn/scripts/tls-verify-nomad

# --tls-export-cert : PATCH AUF RPV qui demande à OpenVPN de placer
# le certificat dans un fichier temporaire et indique le nom du fichier
# dans la variable d'environnement peercert
;tls-export-cert /tmp

# --dh file
#   File containing Diffie Hellman parameters in .pem format (required for
#   --tls-server only).
dh /etc/openvpn/ssl/dh1024.pem

# --reneg-sec n
#   Renegotiate data channel key after n seconds (default=3600).
# AUF RPV : Frequence de renegociation : toutes les 2 heures
reneg-sec 7200

# --hand-window n
#   Handshake Window -- the TLS-based key exchange must finalize within n
#   seconds of handshake initiation by any peer (default = 60 seconds). If the
#   handshake fails we will attempt to reset our connection with our peer and
#   try again. Even in the event of handshake failure we will still use our
#   expiring key for up to --tran-window seconds to maintain continuity of
#   transmission of tunnel data.
# AUF RPV : Delai de handshake a deux minutes pour liaisons degradees
hand-window 120


# --tls-auth file [direction]
#   Add an additional layer of HMAC authentication on top of the TLS
#   control channel to protect against DoS attacks.
#
#   In a nutshell, --tls-auth enables a kind of "HMAC  firewall"  on OpenVPN’s
#   TCP/UDP port, where TLS control channel packets bear‐ ing an incorrect HMAC
#   signature can be dropped immediately with‐ out response.
# FIXME : a ajouter !
# tls-auth /etc/openvpn/tls-auth.key