This adds the ability to have multiple concurrent connections to a single device. This is primarily useful when the network has multiple physical links for aggregated bandwidth. A single connection will never see a higher rate than a single link can give, but multiple connections are load-balanced over multiple links.
It is also incidentally useful for older multi-core CPUs, where bandwidth could be limited by the TLS performance of a single CPU core -- using multiple connections achieves concurrency in the required crypto calculations...
Co-authored-by: Simon Frei <freisim93@gmail.com>
Co-authored-by: tomasz1986 <twilczynski@naver.com>
Co-authored-by: bt90 <btom1990@googlemail.com>
This makes the various protocol priorities configurable among the other
options. With this, it's possible to prefer QUIC over TCP for WAN
connections, for example. Both sides need to be similarly configured for
this to work properly.
The default priority order remains the same as previously (TCP, QUIC,
Relay, with LAN better than WAN).
To make this happen I made each dialer & listener more priority aware,
and moved the check for whether a connection is LAN or not into the
dialer / listener -- this is the new "lanChecker" type that's passed
around.
This adds a cache to the expensive key generation operations. It's fixes
size LRU/MRU stuff to keep memory usage bounded under absurd conditions.
Also closes#8600.
* lib/connections: Cache isLAN decision for later external access.
The check whether a remote device's address is on a local network
currently happens when handling the Hello message, to configure the
limiters. Save the result to the ConnectionInfo and pass it out as
part of the model's ConnectionInfo struct in ConnectionStats().
* gui: Use provided connection attribute to distinguish LAN / WAN.
Replace the dumb IP address check which didn't catch common cases and
actually could contradict what the backend decided. That could have
been confusing if the GUI says WAN, but the limiter is not actually
applied because the backend thinks it's a LAN.
Add strings for QUIC and relay connections to also differentiate
between LAN and WAN.
* gui: Redefine reception level icons for all connection types.
Move the mapping to the JS code, as it is much easier to handle
multiple switch cases by fall-through there.
QUIC is regarded no less than TCP anymore. LAN and WAN make the
difference between levels 4 / 3 and 2 / 1:
{TCP,QUIC} LAN --> {TCP,QUIC} WAN --> Relay LAN --> Relay WAN -->
Disconnected.
This replaces old style errors.Wrap with modern fmt.Errorf and removes
the (direct) dependency on github.com/pkg/errors. A couple of cases are
adjusted by hand as previously errors.Wrap(nil, ...) would return nil,
which is not what fmt.Errorf does.
* Trigger connection loop on config device addition (fixes#7600)
* Also check for device address equality
* Move EqualStrings from api_test to utils, and use in connections/service.go
* Make sure CommitConfiguration cannot block due on the deviceAddressesChanged channel
* Update lib/connections/service.go
Co-authored-by: Jakob Borg <jakob@kastelo.net>
This adds two new configuration options:
// The number of connections at which we stop trying to connect to more
// devices, zero meaning no limit. Does not affect incoming connections.
ConnectionLimitEnough int
// The maximum number of connections which we will allow in total, zero
// meaning no limit. Affects incoming connections and prevents
// attempting outgoing connections.
ConnectionLimitMax int
These can be used to limit the number of concurrent connections in
various ways.
This breaks out some methods from the connection loop to make it simpler
to manage and understand.
Some slight simplifications to remove the `seen` variable (we can filter
`nextDial` based on times are in the future or not, so we don't need to
track `seen`) and adding a minimum loop interval (5s) in case some
dialer goes haywire and requests a 0s redial interval or such.
Otherwise no significant behavioral changes.
This does two things:
- Exclude QUIC from go1.16 builds, automatically, for now, since it
doesn't work and just panics.
- Provide some fake listeners and dialers when QUIC is disabled.
These fake listeners and dialers indicate that they are disabled and
unsupported, which silences "Dialing $address: unknown address scheme:
quic" type of stuff which is not super helpful to the user.
Our authentication is based on device ID (certificate fingerprint) but
we also check the certificate name for ... historical extra security
reasons. (I don't think this adds anything but it is what it is.) Since
that check breaks in Go 1.15 this change does two things:
- Adds a manual check for the peer certificate CommonName, and if they
are equal we are happy and don't call the more advanced
VerifyHostname() function. This allows our old style certificates to
still pass the check.
- Adds the cert name "syncthing" as a DNS SAN when generating the
certificate. This is the correct way nowadays and makes VerifyHostname()
happy in Go 1.15 as well, even without the above patch.
- In the few places where we wrap errors, use the new Go 1.13 "%w"
construction instead of %s or %v.
- Where we create errors with constant strings, consistently use
errors.New and not fmt.Errorf.
- Remove capitalization from errors in the few places where we had that.
