| 1 |
=head1 NAME |
| 2 |
|
| 3 |
gvpe.osdep - os dependent information |
| 4 |
|
| 5 |
=head1 DESCRIPTION |
| 6 |
|
| 7 |
This file tries to capture OS-dependent configuration or build issues, |
| 8 |
quirks and platform limitations, as known. |
| 9 |
|
| 10 |
=head2 TUN vs. TAP interface |
| 11 |
|
| 12 |
Most operating systems nowadays support something called a |
| 13 |
I<tunnel>-device, which makes it possible to divert IPv4 (and often other |
| 14 |
protocols, too) into a userspace daemon like C<gvpe>. This is being |
| 15 |
referred to as a TUN-device. |
| 16 |
|
| 17 |
This is fine for point-to-point tunnels, but for a virtual ethernet, an |
| 18 |
additional ethernet header is needed. This functionality (called a TAP |
| 19 |
device here) is only provided by a subset of the configurations. |
| 20 |
|
| 21 |
On platforms only supporting a TUN-device, gvpe will invoke it's magical |
| 22 |
ethernet emulation package, which currently only handles ARP requests for |
| 23 |
the IPv4 protocol (but more could be added, bu the tincd network drivers |
| 24 |
might need to be modified for this to work). This means that on those |
| 25 |
platforms, only IPv4 will be supported. |
| 26 |
|
| 27 |
Also, since there is no way (currently) to tell gvpe which IP subnets are |
| 28 |
found on a specific host, you will either need to hardwire the MAC address |
| 29 |
for TUN-style hosts on all networks (and avoid ARP altogether, which is |
| 30 |
possible), or you need to send a packet from these hosts into the vpn |
| 31 |
network to tell gvpe the local interface address. |
| 32 |
|
| 33 |
=head2 native/linux |
| 34 |
|
| 35 |
TAP-device; already part of the kernel (only 2.4+ supported, but see |
| 36 |
tincd/linux). This is the configuration tested best, as gvpe is being |
| 37 |
developed on this platform. |
| 38 |
|
| 39 |
To configure the interface, use either iproute2: |
| 40 |
|
| 41 |
ip set $IFNAME address $MAC mtu $MTU up |
| 42 |
ip addr add $IFNAME 10.11.12.13 |
| 43 |
ip route add $IFNAME 10.11.12.13/8 |
| 44 |
|
| 45 |
Or ifconfig: |
| 46 |
|
| 47 |
ifconfig $IFNAME hw ether $MAC mtu $MTU |
| 48 |
ifconfig $IFNAME 10.11.12.13 netmask 255.0.0.0 |
| 49 |
|
| 50 |
To hardwire ARP addresses, use iproute2 (ifconfig can do it, too): |
| 51 |
|
| 52 |
MAC=fe:fd:80:00:00:$(printf "%02x" $NODEID) |
| 53 |
ip neighbour add 10.11.12.13 lladdr $MAC nud permanent dev $IFNAME |
| 54 |
|
| 55 |
=head2 tincd/linux |
| 56 |
|
| 57 |
TAP-device; already part of the kernel (2.2+ supported). See |
| 58 |
C<native/linux> for more info. |
| 59 |
|
| 60 |
=head2 native/cygwin |
| 61 |
|
| 62 |
TAP-device; The TAP device to be used must either be the CIPE driver |
| 63 |
(C<http://cipe-win32.sourceforge.net/>), or (highly recommended) the newer |
| 64 |
TAP-Win32 driver bundled with openvpn (http://openvpn.sf.net/). Just |
| 65 |
download and run the openvpn installer. The only option you need to select |
| 66 |
is the TAP driver. |
| 67 |
|
| 68 |
The MAC need not be set (and in fact I<cannot> be set). The |
| 69 |
MAC address is dynamically being patched into packets and ARP-requests, so |
| 70 |
only IPv4 works with ARP on this platform. |
| 71 |
|
| 72 |
=head2 tincd/freebsd |
| 73 |
|
| 74 |
TAP-device; part of the kernel (since 4.x, maybe earlier). To initialize |
| 75 |
the interface, use this command: |
| 76 |
|
| 77 |
ifconfig $IFNAME ether $MAC mtu $MTU up |
| 78 |
|
| 79 |
=head2 tincd/netbsd |
| 80 |
|
| 81 |
TUN-device; The interface is a point to point-device. To initialize it, |
| 82 |
you currently need to configure it as such, giving it an address on your |
| 83 |
vpn (the exact address doesn't matter), like this: |
| 84 |
|
| 85 |
ifconfig $IFNAME mtu $MTU up |
| 86 |
ifconfig $IFNAME 10.11.12.13 10.55.66.77 |
| 87 |
route add -net 10.0.0.0 10.55.66.77 255.0.0.0 |
| 88 |
ping -c1 10.55.66.77 # ping once to tell gvpe your gw ip |
| 89 |
|
| 90 |
=head2 tincd/openbsd |
| 91 |
|
| 92 |
TUN-device; already part of the kernel. See C<tincd/netbsd> for more information. |
| 93 |
|
| 94 |
=head2 tincd/darwin |
| 95 |
|
| 96 |
TUN-device; See C<tincd/netbsd> for more information. |
| 97 |
|
| 98 |
The necessary kernel extension can be found here: |
| 99 |
|
| 100 |
http://chrisp.de/en/projects/tunnel.html |
| 101 |
|
| 102 |
A newer (and reportedly much more stable) driver that also supports TAP |
| 103 |
operations is available here: |
| 104 |
|
| 105 |
http://www-user.rhrk.uni-kl.de/~nissler/tuntap/ |
| 106 |
|
| 107 |
But GVPE has not been used with it, and has not been ported to it's TAP |
| 108 |
interface. Patches are welcome. |
| 109 |
|
| 110 |
=head2 tincd/solaris |
| 111 |
|
| 112 |
TUN-device; already part of the kernel. see C<tincd/netbsd> for more |
| 113 |
information. Completely untested so far. |
| 114 |
|
| 115 |
=head2 tincd/mingw |
| 116 |
|
| 117 |
TAP-device; see C<native/cygwin> for more information. Completey untested so far. |
| 118 |
|
| 119 |
=head2 tincd/cygwin |
| 120 |
|
| 121 |
Known to be broken. |
| 122 |
|
| 123 |
|
| 124 |
=head1 SEE ALSO |
| 125 |
|
| 126 |
gvpe(5). |
| 127 |
|
| 128 |
=head1 AUTHOR |
| 129 |
|
| 130 |
Marc Lehmann <gvpe@plan9.de> |
| 131 |
|
