2 Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
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.
9 Where special OS features are used, they are usually
10 bracketed with #ifdef HAVE_SOME_FUNCTION.
14 * Linux 2.2+ (supported)
16 * OpenBSD 3.0 (supported but pthreads are broken)
21 * 64 bit platforms -- I have heard reports that
22 OpenVPN runs on Alpha Linux and FreeBSD.
23 * ARM -- I have heard of at least one case
24 where OpenVPN was successfully built and
25 run on the ARM architecture.
29 * Make sure that OpenSSL will build on your
31 * Make sure that a tun or tap virtual device
32 driver exists for your platform. See
33 http://vtun.sourceforge.net/tun/ for examples
34 of tun and tap drivers that have been written
35 for Linux, Solaris, and FreeBSD.
36 * Make sure you have autoconf 2.50+ and
38 * Edit configure.ac, adding platform specific
39 config code, and a TARGET_YOUROS define.
40 * Add platform-specific includes to syshead.h.
41 * Add an #ifdef TARGET_YOUROS to the do_ifconfig()
42 function in tun.c to generate a correct "ifconfig"
43 command for your platform. Note that OpenVPN
44 determines the ifconfig path at ./configure time.
45 * Add an ifconfig_order() variant for your OS so
46 openvpn knows whether to call ifconfig before
47 or after tun/tap dev open.
48 * Add an #ifdef TARGET_YOUROS block in tun.c and define
49 the open_tun, close_tun, read_tun, and write_tun
50 functions. If your tun/tap virtual device is
51 sufficiently generic, you may be able to use the
53 * Add appropriate code to route.c to handle
54 the route command on your platform. This
55 is necessary for the --route option to
57 * After you successfully build OpenVPN, run
58 the loopback tests as described in INSTALL.
59 * For the next test, confirm that the UDP socket
60 functionality is working independently of the
61 tun device, by doing something like:
62 ./openvpn --remote localhost --verb 9 --ping 1 --dev null
63 * Now try with --remote [a real host]
64 * Now try with a real tun/tap device, you will
65 need to figure out the appropriate ifconfig
66 command to use once openvpn has opened the tun/tap
68 * Once you have simple tests working on the tun device,
69 try more complex tests such as using TLS mode.
70 * Stress test the link by doing ping -f across it.
71 * Make sure that packet fragmenting is happening
72 correctly by doing a ping -s 2000 or higher.
73 * Ensure that OpenVPN on your platform will talk
74 to OpenVPN on other platforms such as Linux.
75 Some tun/tap driver implementations will prepend
76 unnecessary stuff onto the datagram that must be
77 disabled with an explicit ioctl call if cross-platform
78 compatibility is to be preserved. You can see some
79 examples of this in tun.c.
80 * If your system supports pthreads, try building
81 with ./configure --enable-pthread and do a stress
83 * Try the ultimate stress test which is --gremlin
84 --reneg-sec 10 in TLS mode (preferably with pthreads
85 enabled), then do a flood ping across the tunnel
86 (ping -f remote-endpoint) in both directions and let
87 it run overnight. --gremlin will induce massive
88 corruption and packet loss, but you win if you
89 wake up the next morning and both peers are still
90 running and occasionally even succeeding in their
91 attempted once-per-10-seconds TLS handshake.
92 * When it's working, submit your patch to
93 <openvpn-devel@lists.sourceforge.net>