Keep track of the number of correct, non-replayed UDP packets that have been
received, regardless of their content. This can be compared to the sequence
number to determine the real packet loss.
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).
We don't need to search the whole edge tree, we can use the node's own edge
tree since each edge has a pointer to its reverse. Also, we do need to make
sure we try the reflexive address often.
Before it would always use the first socket, and always send an IPv4 broadcast packet. That
works fine in a lot of situations, but it is better to try all sockets, and to send IPv6 packets
on IPv6 sockets. This is especially important for users that are on IPv6-only networks or that
have multiple physical network interfaces, although in the latter case it probably requires
them to use the ListenAddress variable to create a separate socket for each interface.
Before, when tinc saw a packet larger than the PMTU with a VLAN tag, it would
not know what to do with it, and would just forward it via TCP. Now, tinc
handles 802.1q packets correctly, as long as there is only one tag.
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.
