Dear Jim and other OpenVPN hackers, there is an OpenVPN regression, apparently affecting 2.1 on FreeBSD-8, and caused by OpenVPN configuring the local address on a P2P interface for the local AND ALSO the remote address. See http://lists.freebsd.org/pipermail/freebsd-current/2009-July/010032.html and followups for details. Am 30.07.2009, 08:40 Uhr, schrieb Stefan Bethke <stb_at_lassitu.de>: > I'm not sure if that is a more general problem with OpenVPN (at least in > --topology subnet mode), or a specific problem in the FreeBSD-specific > code. I just looked at a Linux box connected to the same OpenVPN > server, and their ifconfig invocation looks different from ours, so the > FreeBSD-specific code at least plays some role. > > I'd still like to know whether the change to the routing code is > intentional or a regression. Stefan, Which version of OpenVPN are you using? It might seem that this is a FreeBSD regression, as OpenVPN assumes this about --topology subnet, so that the using of the local address as remote is intentional. (This is from the current OpenVPN 2.1-RC manpage): subnet -- Use a subnet rather than a point-to-point topology by configuring the tun interface with a local IP address and subnet mask, similar to the topology used in --dev tap and ethernet bridging mode. This mode allocates a single IP address per con- necting client and works on Windows as well. Only available when server and clients are OpenVPN 2.1 or higher, or OpenVPN 2.0.x which has been manually patched with the --topology direc- tive code. When used on Windows, requires version 8.2 or higher of the TAP-Win32 driver. When used on *nix, requires that the tun driver supports an ifconfig(8) command which sets a subnet instead of a remote endpoint IP address. I see this in the ChangeLog: 2006.04.05 -- Version 2.1-beta12 ... * "topology subnet" fix for FreeBSD (Benoit Bourdin). ... And it appears that exactly this patch may be the culprit. This is from the OpenVPN 2.1 source repository: ------------------------------------------------------------------------ r986 | james | 2006-04-05 08:28:19 +0200 (Wed, 05 Apr 2006) | 2 lines Changed paths: M /branches/BETA21/openvpn/tun.c "topology subnet" fix for FreeBSD (Benoit Bourdin). ------------------------------------------------------------------------ Index: tun.c =================================================================== --- tun.c (Revision 985) +++ tun.c (Revision 986) _at__at_ -795,19 +795,42 _at__at_ ifconfig_remote_netmask, tun_mtu ); - else - openvpn_snprintf (command_line, sizeof (command_line), + else { + if (tt->topology == TOP_SUBNET) + openvpn_snprintf (command_line, sizeof (command_line), + IFCONFIG_PATH " %s %s %s netmask %s mtu %d up", + actual, + ifconfig_local, + ifconfig_local, + ifconfig_remote_netmask, + tun_mtu + ); + else + openvpn_snprintf (command_line, sizeof (command_line), IFCONFIG_PATH " %s %s netmask %s mtu %d up", actual, ifconfig_local, ifconfig_remote_netmask, tun_mtu ); + } msg (M_INFO, "%s", command_line); system_check (command_line, es, S_FATAL, "FreeBSD ifconfig failed"); tt->did_ifconfig = true; + /* Add a network route for the local tun interface */ + if (!tun && tt->topology == TOP_SUBNET) + { + struct route r; + CLEAR (r); + r.defined = true; + r.network = tt->local & tt->remote_netmask; + r.netmask = tt->remote_netmask; + r.gateway = tt->local; + add_route (&r, tt, 0, es); + } + #elif defined (WIN32) { /* -- Matthias AndreeReceived on Thu Jul 30 2009 - 06:11:28 UTC
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