tailscale/control/controlclient/noise_test.go
David Anderson 02ad987e24 control/controlbase: make the protocol version number selectable.
This is so that we can plumb our client capability version through
the protocol as the Noise version. The capability version increments
more frequently than strictly required (the Noise version only needs
to change when cryptographically-significant changes are made to
the protocol, whereas the capability version also indicates changes
in non-cryptographically-significant parts of the protocol), but this
gives us a safe pre-auth way to determine if the client supports
future protocol features, while still relying on Noise's strong
assurance that the client and server have agreed on the same version.

Currently, the server executes the same protocol regardless of the
version number, and just presents the version to the caller so they
can do capability-based things in the upper RPC protocol. In future,
we may add a ratchet to disallow obsolete protocols, or vary the
Noise handshake behavior based on requested version.

Updates #3488

Signed-off-by: David Anderson <danderson@tailscale.com>
2022-04-07 13:25:28 -07:00

29 lines
1009 B
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package controlclient
import (
"math"
"testing"
"tailscale.com/tailcfg"
)
// maxAllowedNoiseVersion is the highest we expect the Tailscale
// capability version to ever get. It's a value close to 2^16, but
// with enough leeway that we get a very early warning that it's time
// to rework the wire protocol to allow larger versions, while still
// giving us headroom to bump this test and fix the build.
//
// Code elsewhere in the client will panic() if the tailcfg capability
// version exceeds 16 bits, so take a failure of this test seriously.
const maxAllowedNoiseVersion = math.MaxUint16 - 5000
func TestNoiseVersion(t *testing.T) {
if tailcfg.CurrentCapabilityVersion > maxAllowedNoiseVersion {
t.Fatalf("tailcfg.CurrentCapabilityVersion is %d, want <=%d", tailcfg.CurrentCapabilityVersion, maxAllowedNoiseVersion)
}
}