Guus Sliepen [Sat, 29 Oct 2016 13:24:34 +0000 (15:24 +0200)]
Use AES256 and SHA256 by default, also for the meta-connections.
At the start of the decade, there were still distributions that shipped
with versions of OpenSSL that did not support these algorithms. By now
everyone should support them. The old defaults were Blowfish and SHA1,
both of which are not considered secure anymore.
The meta-protocol now always uses AES in OFB mode, but the key length
will adapt to the one specified by the Cipher option. The digest for the
meta-protocol is hardcoded to SHA256.
Guus Sliepen [Sun, 5 Jun 2016 13:23:07 +0000 (15:23 +0200)]
Preserve IPv6 scope_id in edges.
When creating an edge after authenticating a peer, we copy the address
used for the TCP connection, but change the port to that used for UDP.
But the way we did it discarded the scope_id for IPv6 addresses. This
prevented UDP communication from working correctly when connecting to a
peer on the same LAN using an IPv6 link-local address.
Thanks to Rafał Leśniak for pointing out this issue.
Use devname() if available to support devfs cloning on BSD.
Some BSD flavors allow opening /dev/tun and/or /dev/tap, which automatically
create a new tun or tap interface with an unused number. To find out which
number the interface got, you have to call devname() on the device file
that was opened.
The semantics are different from the way Linux's /dev/tun works though.
In particular, after closing the device, the interface will continue to exist.
Restarting tincd would cause the old interface to stay around, and a new
one to be created. One could add a tinc-down script with the following line:
ifconfig $INTERFACE destroy
But that is still no guarantee that restarting tinc will give you the same
interface. So the default tun and tap device will stay /dev/tun0 and /dev/tap0
for all BSD flavors to avoid surprises for existing users.
Guus Sliepen [Sat, 27 Feb 2016 13:46:01 +0000 (14:46 +0100)]
Add warnings for bad combinations of Device and Interface.
On Linux, the name of the tun/tap interface can be set freely. However,
on most other operating systems, tinc cannot change the name of the
interface. In those situations, it is possible to specify a Device and
an Interface that conflict with each other. On BSD, this can cause
$INTERFACE to be set incorrectly, on Windows, this results in a
potentially unreliable way in which a TAP-Win32 interface is selected.
Guus Sliepen [Mon, 18 Jan 2016 12:58:46 +0000 (13:58 +0100)]
Fix compatibility with TAP-Win32 9.0.0.21 and later.
Tinc was a bit sloppy writing packets to the TAP-Win32 device using
overlapped I/O. It worked with older versions of the driver, but it
caused lots of dropped packets with newer versions of the driver (that
use the NDIS 6 API).
Guus Sliepen [Sun, 1 Nov 2015 20:07:56 +0000 (21:07 +0100)]
Update "now" after connect() when making outgoing connections.
It could be that address resolution takes a long time, don't let that
count against a connection. This is especially important when using a
nameserver from the VPN.
Fix source IP address for ICMP unreachable packets generated by tinc.
Try to send ICMP unreachable replies from an address assigned to the
local machine, instead of the destination address of the original
packet.
The address is found by looking up the route towards the sender of
the packet that generated the error; in usual configurations, this
is the tinc interface.
This also fixes the traceroute display in mtr when using the
DecrementTTL option.
Guus Sliepen [Sun, 7 Jun 2015 20:25:22 +0000 (22:25 +0200)]
Fix autoconf check for function attributes.
GCC warns when a function attribute has no effect. The autoconf check
turns warnings about attributes into errors, therefore thinking that
they did not work. The reason was that the test function returned void,
which is not suitable for checking both __malloc__ and
__warn_unused_result__.
Guus Sliepen [Sun, 3 May 2015 18:06:12 +0000 (20:06 +0200)]
Never call putenv() with data on the stack.
Even though we are using putenv() here to remove items from the
environment, there is no guarantee that putenv() doesn't add the
argument to the environment anyway. In that case, we have to make sure
that it doesn't go away. We also don't want a memory leak, so keep a
list of things we unputenv()ed around, so we can reuse things.
Thanks to Poul-Henning Kamp for pointing out this problem.
Guus Sliepen [Mon, 9 Feb 2015 14:06:12 +0000 (15:06 +0100)]
Always call res_init() before getaddrinfo().
Unfortunately, glibc assumes that /etc/resolv.conf is a static file that
never changes. Even on servers, /etc/resolv.conf might be a dynamically
generated file, and we never know when it changes. So just call
res_init() every time, so glibc uses up-to-date nameserver information.
Guus Sliepen [Mon, 22 Dec 2014 17:17:11 +0000 (18:17 +0100)]
Check whether res_init() really lives in libresolv.
On some platforms (Mac OS X for example), the res_init() function requires
linking with libresolv. On others (Linux, OpenBSD for example), res_init()
lives in libc.
Tomislav Čohar [Tue, 26 Aug 2014 22:25:12 +0000 (00:25 +0200)]
Configure minimum reconnect timeouts.
Enable the configuration of minimum reconnect timeout via a
configuration directive "MinTimeout". This functionality is missing in
the default tinc stable distribution. The minimum timeout is, in code,
set to 0 seconds. This patch makes it configurable.
You might ask yourself why is that needed at all ?
Well, we've been using tinc with success for quite some time in a cross DC
setup. Tinc is used to create a virtual network switch and to connect our
distributed database nodes into a virtual local network. Our database nodes
exchange information, synchronize and do failover over the created
tinc-backed network.
Every now and then, when a node has a physical networking issue and is
unreachable by some or all neighboring nodes, tinc will relay traffic over
reachable neighboring nodes and thus save our cluster. But, sometimes,
especially when BGP route changes take place, minor outages of physical
connectivity towards some nodes may cause tinc to become as reliable as
packet-loss is :).
Tinc is fast, it can and does re-establish a lost connection in a jiffy,
but it cannot detect the reason for the loss of the connection. A
re-established connection might last for a few seconds (ping timeout) to
get lost again just because the packet loss is huge at that time. Then it
reconnects again and the story repeats itself.
This process keeps repeating until the physical network stabilizes. Packet
loss on a physical link means disaster in a database replication scenario.
In such cases it is better for tinc to remain disconnected from the
unreachable/destabilized nodes for some time and relay traffic over the
reachable (unaffected) nodes then to use an unreliable route.
This patch enables us to slow down the re-connection process and eliminate
application level issues we had.
Guus Sliepen [Sun, 11 May 2014 14:35:37 +0000 (16:35 +0200)]
Drop h and hh length modifiers from printf format strings.
C already guarantees that chars and shorts get passed as int. The few uses in tinc are mainly
to print fields of struct addrinfo, and fields like ai_family have different sizes on different
platforms, which actually caused some warnings to be generated.