It seems like a lot of overhead to call access() for every possible extension
defined in PATHEXT, but apparently this is what Windows does itself too. At
least this avoids calling system() when the script one is looking for does not
exist at all.
Since the tinc utility also needs to call scripts, execute_script() is now
split off into its own source file.
When reloading the configuration file via the tinc command, the user will get
an error message if reloading has failed. However, no such warning exists when
sending a HUP signal. Previously, tincd would exit in both cases, but with a
zero exit code. Now it will exit with code 1 when reloading fails after a
SIGHUP, but tincd will keep running if it is signaled via the tinc command.
Instead, the tinc command will exit with a non-zero exit code.
The retry() function would only abort connections that were in progress of
being made, it wouldn't reschedule the outgoing connections that had been
sleeping.
We were checking only for readability, which is not a problem for normal
connections, since the server side of a connection will always send an ID
request. But when using a proxy, the proxy server doesn't send anything before
the client, so tinc would not see that its connection to the proxy had already
been established.
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.
The tree functions were never used on the connection_tree, a list is more appropriate.
Also be more paranoid about connections disappearing while traversing the list.
Struct outgoing_ts and connection_ts were depending too much on each other,
causing lots of problems, especially the reuse of a connection_t. Now, whenever
a connection is closed it is immediately removed from the list of connections
and destroyed.
In retry() the function do_outgoing_connection() is called, which can delete
items from the connection_tree, so when walking the tree we must first save the
pointer to the next item.
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.
When making outgoing connections, tinc goes through the list of Addresses and
tries all of them until one succeeds. However, before it would consider
establishing a TCP connection a success, even when the authentication failed.
This would be a problem if the first Address would point to a hostname and port
combination that belongs to the wrong tinc node, or perhaps even to a non-tinc
service, causing tinc to endlessly try this Address instead of moving to the
next one.
Problem found by Delf Eldkraft.
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.
Apart from the platform specific tun/tap driver, link with the dummy and
raw_socket devices, and optionally with support for UML and VDE devices.
At runtime, the DeviceType option can be used to select which driver to
use.
First of all, if there really are two nodes with the same name, much
more than 10 contradicting ADD_EDGE and DEL_EDGE messages will be sent.
Also, we forgot to reset the counters when nothing happened.
In case there is a ADD_EDGE/DEL_EDGE storm, we do not shut down, but
sleep an increasing amount of time, allowing tinc to recover gracefully
from temporary failures.
Instead of UNIX time, the log messages now start with the time in RFC3339
format, which human-readable and still easy for the computer to parse and sort.
The HUP signal will also cause the log file to be closed and reopened, which is
useful when log rotation is used. If there is an error while opening the log
file, this is logged to stderr.
