We do this by creating an umbilical between the CLI and the daemon. The
daemon pipes log messages to the CLI until it starts the main loop. The
daemon then cuts the umbilical. The CLI copies all the received log
messages to stderr, and the last byte indicates whether the daemon
started succesfully or not, so the CLI can exit with a useful exit code.
This gets rid of xasprintf() in a number of places, and removes the need
to free() the temporary strings. A few potential memory leaks have been
fixed.
This dumps the name of the invitation file, as well as the name of the
node that is being invited. This can make it easier to find the
invitation file belonging to a given node.
Instead of using the hardcoded version number in configure.ac, this
makes tinc use the live version reported by "git describe",
queried on-the-fly during the build process and regenerated for every
build.
This makes tinc version output more useful, as tinc will now display the
number of commits since the last tag as well as the commit the binary is
built from, following the format described in git-describe(1).
Here's an example of tincd --version output:
tinc version release-1.1pre10-48-gc149315 (built Jun 29 2014 15:21:10, protocol 17.3)
When building directly from a release tag, this will look like the following:
tinc version release-1.1pre10 (built Jun 29 2014 15:21:10, protocol 17.3)
(Note that the format is slightly different - because of the way the
tags are named, it says "release-1.1pre10" instead of just "1.1pre10")
If git describe fails (for example when building from a release
tarball), the build automatically falls back to the autoconf-provided
VERSION macro (i.e. the old behavior).
This makes sure MTU_INFO messages are only sent at the maximum rate of
5 per second (by default). As usual with these "probe" mechanisms, the
rate of these messages cannot be higher than the rate of data packets
themselves, since they are sent from the RX path.
This makes sure UDP_INFO messages are only sent at the maximum rate of
5 per second (by default). As usual with these "probe" mechanisms, the
rate of these messages cannot be higher than the rate of data packets
themselves, since they are sent from the RX path.
This will report possible problems in the configuration files, and in
some cases offers to fix them.
The code is far from perfect yet. It expects keys to be in their default
locations, it doesn't check for Public/PrivateKey[File] statemetns yet.
It also does not correctly handle Ed25519 public keys yet.
This introduces a new configuration option,
UDPDiscoveryKeepaliveInterval, which is used as the UDP discovery
interval once the UDP tunnel is established. The pre-existing option,
UDPDiscoveryInterval, is therefore only used before UDP connectivity
is established.
The defaults are set so that tinc sends UDP pings more aggressively
if the tunnel is not established yet. This is appropriate since the
size of probes in that scenario is very small (16 bytes).
This adds a new mechanism by which tinc can determine if a node is
reachable via UDP. The new mechanism is currently redundant with the
PMTU discovery mechanism - that will be fixed in a future commit.
Conceptually, the UDP discovery mechanism works similarly to PMTU
discovery: it sends UDP probes (of minmtu size, to make sure the tunnel
is fully usable), and assumes UDP is usable if it gets replies. It
assumes UDP is broken if too much time has passed since the last reply.
The big difference with the current PMTU discovery mechanism, however,
is that UDP discovery probes are only triggered as part of the
packet TX path (through try_tx()). This is quite interesting, because
it means tinc will never send UDP pings more often than normal packets,
and most importantly, it will automatically stop sending pings as soon
as packets stop flowing, thereby nicely reducing network chatter.
Of course, there are small drawbacks in some edge cases: for example,
if a node only sends one packet every minute to another node, these
packets will only be sent over TCP, because the interval between packets
is too long for tinc to maintain the UDP tunnel. I consider this a
feature, not a bug: I believe it is appropriate to use TCP in scenarios
where traffic is negligible, so that we don't pollute the network with
pings just to maintain a UDP tunnel that's seeing negligible usage.
The option "--disable-legacy-protocol" was added to the configure
script. The new protocol does not depend on any external crypto
libraries, so when the option is used tinc is no longer linked to
OpenSSL's libcrypto.
This introduces a new type of identifier for nodes, which complements
node names: node IDs. Node IDs are defined as the first 6 bytes of the
SHA-256 hash of the node name. They will be used in future code in lieu
of node names as unique node identifiers in contexts where space is at
a premium (such as VPN packets).
The semantics of node IDs is that they are supposed to be unique in a
tinc graph; i.e. two different nodes that are part of the same graph
should not have the same ID, otherwise things could break. This
solution provides this guarantee based on realistic probabilities:
indeed, according to the birthday problem, with a 48-bit hash, the
probability of at least one collision is 1e-13 with 10 nodes, 1e-11
with 100 nodes, 1e-9 with 1000 nodes and 1e-7 with 10000 nodes. Things
only start getting hairy with more than 1 million nodes, as the
probability gets over 0.2%.
Successfully getting an existing variable ("tinc get name") should
not result in an error exitcode (1) from the tinc command.
This changes the result of test/commandline.test from FAIL to PASS.
Some tinc commands, such as "tinc generate-keys", use the terminal to
ask the user for information. This can be bypassed by making sure
there is no terminal, which is trivial on *nix but might require
jumping through some hoops on Windows depending on how the command is
invoked.
This commit adds a --batch option that ensures tinc will never ask the
user for input, even if it is attached to a terminal.
When invoking tincd, tinc start currently uses the execvp() function,
which doesn't behave well in a console as the console displays a new
prompt before the subprocess finishes (which makes me suspect the exit
value is not handled at all). This new code uses spawnvp() instead,
which seems like a better fit.
When invoking "tinc start" with spaces in the path, the following
happens:
> "c:\Program Files (x86)\tinc\tinc.exe" start
c:\Program: unrecognized argument 'Files'
Try `c:\Program --help' for more information.
This is caused by inconsistent handling of command line strings between
execvp() and the spawned process' CRT, as documented on MSDN:
http://msdn.microsoft.com/library/431x4c1w.aspx
Instead of using a hardcoded version number in configure.ac, this makes
tinc use the live version reported by "git describe", queried on-the-fly
during the build process and regenerated for every build.
This provides several advantages:
- Less redundancy: git is now the source of truth for version
information, no need to store it in the repository itself.
- Simpler release process: just creating a git tag automatically
updates the version. No need to change files.
- More useful version information: tinc will now display the number of
commits since the last tag as well as the commit the binary is built
from, following the format described in git-describe(1).
Here's an example of tincd --version output:
tinc version release-1.1pre10-48-gc149315 (built Jun 29 2014 15:21:10, protocol 17.3)
When building directly from a release tag, this would like the following:
tinc version release-1.1pre10 (built Jun 29 2014 15:21:10, protocol 17.3)
(Note that the format is slightly different - because of the way the
tags are named, it says "release-1.1pre10" instead of just "1.1pre10")
This prevents the date and time shown in version information from
getting stale because of partial builds. With these changes, date and
time information is written to a dedicated object file that gets rebuilt
every time make is run, even if there are no changes.
In addition to the remote address, each edge now stores the local address from
the point of view of the "from" node. This information is then made available
to other nodes through a backwards-compatible extension to ADD_EDGE messages.
This information can be used in future code to improve packet routing.
When using socket functions, "sockerrno" is supposed to be used to
retrieve the error code as opposed to "errno", so that it is translated
to the correct call on Windows (WSAGetLastError() - Windows does not
update errno on socket errors). Unfortunately, the use of sockerrno is
inconsistent throughout the tinc codebase, as errno is often used
incorrectly on socket-related calls.
This commit fixes these oversights, which improves socket error
handling on Windows.
- Try to prevent SIGPIPE from being sent for errors sending to the control
socket. We don't outright block the SIGPIPE signal because we still want the
tinc CLI to exit when its output is actually sent to a real (broken) pipe.
- Don't call exit() from top(), and properly detect when the control socket is
closed by the tincd.
When creating invitations or using them to join a VPN, and the tinc command is
not run interactively (ie, when stdin and stdout are not connected or
redirected to/from a file), don't ask questions. If normally tinc would ask for
a confirmation, just assume the default answer instead. If tinc really needs
some input, just print an error message instead.
In case an invitation is used for a VPN which uses a netname that is already in
use on the local host, tinc will store the configuration in a temporary
directory. Normally it asks for an alternative netname and then renames the
temporary directory, but when not run interactively, it now just prints the
location of the unchanged temporary directory.
ListenAddress works the same as BindToAddress, except that from now on,
explicitly binding outgoing packets to the address of a socket is only done for
sockets specified with BindToAddress.
The tinc utility defered calling WSAStartup() until it tried to connect to a
running tinc daemon. However, socket functions are now also used for other
things (like joining another VPN using an invitation). Now we just
unconditionally call WSAStartup() early in main().
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.
As mentioned by Erik Tews, calling fchmod() after fopen() leaves a small window
for exploits. As long as tinc is single-threaded, we can use umask() instead to
reduce file permissions. This also works when creating the AF_UNIX control socket.
The umask of the user running tinc(d) is used for most files, except for the
private keys, invitation files, PID file and control socket.
In case no explicit netname of configuration directory is specified when
accepting an invitation, the netname specified in the invitation data is
used. However, this new netname is only known after making the connection
to the server. If the new netname conflicts with an existing one at the
client, we ask the user for a netname that doesn't conflict. However, we
should first finish accepting the invitation, so we don't run into the
problem that the server times out and cancels the invitation. So, we create
a random netname and store the files there, and only after we finish
accepting the invitation we ask the user for a better netname, and then
just rename the temporary directory to the final name.
