There are several reasons for this:
- MacOS/X doesn't support polling the tap device using kqueue, requiring a
workaround to fall back to select().
- On Windows only sockets are properly handled, therefore tinc uses a second
thread that does a blocking ReadFile() on the TAP-Win32/64 device. However,
this does not mix well with libevent.
- Libevent, event just the core, is quite large, and although it is easy to get
and install on many platforms, it can be a burden.
- Libev is more lightweight and seems technically superior, but it doesn't
abstract away all the platform differences (for example, async events are not
supported on Windows).
When set to a non-zero value, tinc will try to maintain exactly that number of
meta connections to other nodes. If there are not enough connections, it will
periodically try to set up an outgoing connection to a random node. If there
are too many connections, it will periodically try to remove an outgoing
connection.
When the Proxy option is used, outgoing connections will be made via the
specified proxy. There is no support for authentication methods or for having
the proxy forward incoming connections, and there is no attempt to proxy UDP.
When the "Broadcast = direct" option is used, broadcast packets are not sent
and forwarded via the Minimum Spanning Tree to all nodes, but are sent directly
to all nodes that can be reached in one hop.
One use for this is to allow running ad-hoc routing protocols, such as OLSR, on
top of tinc.
When the Name starts with a $, the rest will be interpreted as the name of an
environment variable containing the real Name. When Name is $HOST, but this
environment variable does not exist, gethostname() will be used to set the
Name. In both cases, illegal characters will be converted to underscores.
DeviceType = multicast allows one to specify a multicast address and port with
a Device statement. Tinc will then read/send packets to that multicast group
instead of to a tun/tap device. This allows interaction with UML, QEMU and KVM
instances that are listening on the same group.
This allows tincctl to receive log messages from a running tincd,
independent of what is logged to syslog or to file. Tincctl can receive
debug messages with an arbitrary level.
This allows administrators who frequently want to work with one tinc
network to omit the -n option. Since the NETNAME variable is set by
tincd when executing scripts, this makes it slightly easier to use
tincctl from within scripts.
The Broadcast option can be used to cause tinc to drop all broadcast and
multicast packets. This option might be expanded in the future to selectively
allow only some broadcast packet types.
