The generate-keys command now generates both an RSA and an ECDSA keypair,
but one can generate-rsa-keys or generate-ecdsa-keys to just generate one type.
The pid is now written first, so that a version 1.0.x tincd can be used to stop
a running version 1.1 tincd. Getsockname() is used to determine the address of
the first listening socket, so that tincctl can connect to the local tincd even
if AddressFamily = ipv6, or if BindToAddress or BindToInterface is used.
This would allow tincctl to connect to a remote tincd, or to a local tincd that
isn't listening on localhost, for example if it is using the BindToInterface or
BindToAddress options.
The control socket code was completely different from how meta connections are
handled, resulting in lots of extra code to handle requests. Also, not every
operating system has UNIX sockets, so we have to resort to another type of
sockets or pipes for those anyway. To reduce code duplication and make control
sockets work the same on all platforms, we now just connect to the TCP port
where tincd is already listening on.
To authenticate, the program that wants to control a running tinc daemon must
send the contents of a cookie file. The cookie is a random 256 bits number that
is regenerated every time tincd starts. The cookie file should only be readable
by the same user that can start a tincd.
Instead of the binary-ish protocol previously used, we now use an ASCII
protocol similar to that of the meta connections, but this can still change.
UNIX domain sockets, of course, don't exist on Windows. For now, when compiling
tinc in a MinGW environment, try to use a TCP socket bound to localhost as an
alternative.
This provides reasonable security even on Solaris. The sysadmin is
responsible for securing the control socket's ancestors from the
grandparent on.
We could add a cryptographic handshake later if desired.
