PORTS

   1 OpenVPN
   2 Copyright (C) 2002-2024 OpenVPN Inc <sales@openvpn.net>
   3
   4   OpenVPN has been written to try to avoid features
   5   that are not standardized well across different
   6   OSes, so porting OpenVPN itself will probably be
   7   straightforward if a tun or tap driver already exists.
   8
   9   Where special OS features are used, they are usually
  10   bracketed with #ifdef HAVE_SOME_FUNCTION.
  11
  12 PLATFORM STATUS:
  13
  14 Tier 1 platforms - actively tested for every source commit, across
  15 multiple operating system versions
  16
  17   * Windows 7 and newer
  18   * Windows Server 2012 and newer
  19   * Linux
  20   * FreeBSD
  21   * macOS
  22
  23 Tier 2 platforms - it worked at some point, but is not actively tested
  24 on "latest OS, latest OS libraries" so might break if larger changes
  25 are done on the platform side
  26
  27   * OpenBSD
  28   * NetBSD
  29   * DragonFly BSD
  30   * Solaris
  31   * AIX
  32
  33 For underlying CPU architecture, everything 32 bit or 64 bit (Intel, AMD,
  34 ARM, PowerPC, SPARC*) should work fine.  16 bit Architectures are unlikely
  35 to work.
  36
  37
  38 PORTING GUIDELINE TO A NEW PLATFORM:
  39
  40   * Make sure that OpenSSL will build on your
  41     platform.
  42   * Make sure that a tun or tap virtual device
  43     driver exists for your platform.  See
  44     http://vtun.sourceforge.net/tun/ for examples
  45     of tun and tap drivers that have been written
  46     for Linux, Solaris, and FreeBSD.
  47   * Make sure you have autoconf 2.50+ and
  48     automake 1.6+.
  49   * Edit configure.ac, adding platform specific
  50     config code, and a TARGET_YOUROS define.
  51   * Add platform-specific includes to syshead.h.
  52   * Add an #ifdef TARGET_YOUROS to the do_ifconfig()
  53     function in tun.c to generate a correct "ifconfig"
  54     command for your platform.  Note that OpenVPN
  55     determines the ifconfig path at ./configure time.
  56   * Possibly add an ifconfig_order() variant for your OS so
  57     openvpn knows whether to call ifconfig before
  58     or after tun/tap dev open.
  59   * Add an #ifdef TARGET_YOUROS block in tun.c and define
  60     the open_tun, close_tun, read_tun, and write_tun
  61     functions.  If your tun/tap virtual device is
  62     sufficiently generic, you may be able to use the
  63     default case.
  64   * Add appropriate code to route.c to handle
  65     the route command on your platform.  This
  66     is necessary for the --route option to
  67     work correctly.
  68   * After you successfully build OpenVPN, run
  69     the loopback tests as described in INSTALL.
  70   * For the next test, confirm that the UDP socket
  71     functionality is working independently of the
  72     tun device, by doing something like:
  73       ./openvpn --remote localhost --verb 9 --ping 1 --dev null
  74   * Now try with --remote [a real host]
  75   * Now try with a real tun/tap device, you will
  76     need to figure out the appropriate ifconfig
  77     command to use once openvpn has opened the tun/tap
  78     device.
  79   * Once you have simple tests working on the tun device,
  80     try more complex tests such as using TLS mode.
  81   * Stress test the link by doing ping -f across it.
  82   * Make sure that packet fragmenting is happening
  83     correctly by doing a ping -s 2000 or higher.
  84   * Ensure that OpenVPN on your platform will talk
  85     to OpenVPN on other platforms such as Linux.
  86     Some tun/tap driver implementations will prepend
  87     unnecessary stuff onto the datagram that must be
  88     disabled with an explicit ioctl call if cross-platform
  89     compatibility is to be preserved.  You can see some
  90     examples of this in tun.c.
  91   * Try the ultimate stress test which is --gremlin --reneg-sec 10
  92     in TLS mode then do a flood ping across the tunnel
  93     (ping -f remote-endpoint) in both directions and let
  94     it run overnight.  --gremlin will induce massive
  95     corruption and packet loss, but you win if you
  96     wake up the next morning and both peers are still
  97     running and occasionally even succeeding in their
  98     attempted once-per-10-seconds TLS handshake.
  99   * When it's working, submit your patch to
 100     <openvpn-devel@lists.sourceforge.net>
 101     and rejoice :)