Fix TDP/RDP termination

[ibeckermayer]

In #13479 I cleaned up the Client's API and centralized the connection and memory cleanup, but I also removed a deferred c.Close() from the streaming goroutines. This change meant that in the most common case of the TDP input streaming goroutine erroring due to the browser tab being closed:

teleport/lib/srv/desktop/rdp/rdpclient/client.go

Lines 285 to 287 in 7c8da82

	msg, err := c.cfg.Conn.InputMessage()
	if errors.Is(err, io.EOF) {
	return

the RDP streaming goroutine was no longer being terminated immediately, causing it to awkwardly hang around failing calls until the idle timeout (possibly relates to #13723).

This change reintroduces the deferred c.close() to streaming goroutines and also adds insurance that the TDP connection is closed in c.close(), so that whenever one goroutine terminates, the other one isn't left far behind.

[zmb3]

I'm also curious how this behaves if windows terminates the connection - do we see any confusing warnings or errors in the console?

(test by killing/rebooting a windows VM during a session)

[ibeckermayer]

I'm also curious how this behaves if windows terminates the connection - do we see any confusing warnings or errors in the console?

(test by killing/rebooting a windows VM during a session)

Good question -- the screen just freezes for a while (which is sorta confusing), until the rust rdp client times out here

teleport/lib/srv/desktop/rdp/rdpclient/src/lib.rs

Line 619 in 6f93378

let res = client.rdp_client.lock().unwrap().read(|rdp_event| {

(takes about 20sec or so).

Nothing too crazy looking in the logs:

2022-06-27T16:58:05-04:00 DEBU [PROC:1]    Broadcasting event. event:TeleportDegraded pid:11293.1 service/supervisor.go:376
[2022-06-27T20:58:07Z ERROR rdp_client] RDP read failed: Io(Os { code: 60, kind: TimedOut, message: "Operation timed out" })
2022-06-27T16:58:07-04:00 WARN [WINDOWS_D] Failed reading RDP output frame: 1 client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 rdp-addr:172.16.97.147:3389 rdpclient/client.go:265
2022-06-27T16:58:07-04:00 WARN [WINDOWS_D] Failed reading TDP input message: read tcp [::1]:3028->[::1]:56465: use of closed network connection client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 rdp-addr:172.16.97.147:3389 rdpclient/client.go:289
2022-06-27T16:58:07-04:00 INFO [WINDOWS_D] TDP input streaming finished client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 rdp-addr:172.16.97.147:3389 rdpclient/client.go:290
[2022-06-27T20:58:07Z DEBUG rustls::conn] Sending warning alert CloseNotify
[2022-06-27T20:58:07Z ERROR rdp_client] failed writing RDP keyboard event: Io(Os { code: 32, kind: BrokenPipe, message: "Broken pipe" })
2022-06-27T16:58:07-04:00 DEBU [SSH:PROXY] Closed connection [::1]:56466. sshutils/server.go:449
2022-06-27T16:58:07-04:00 INFO [WINDOWS_D] RDP output streaming finished client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 rdp-addr:172.16.97.147:3389 rdpclient/client.go:273
2022-06-27T16:58:07-04:00 WARN [WINDOWS_D] error closing the RDP connection client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 rdp-addr:172.16.97.147:3389 rdpclient/client.go:529
2022-06-27T16:58:07-04:00 DEBU [WINDOWS_D] Windows desktop disconnected client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 desktop/windows_server.go:758
2022-06-27T16:58:07-04:00 DEBU [WINDOWS_D] Releasing associated resources - context has been closed. client-ip:::1 desktop-addr:172.16.97.147:3389 desktop-name:WIN-1E6JDI6PHQA-teleport-dev pid:11293.1 srv/monitor.go:253

@zmb3

[ibeckermayer]

@nklaassen @LKozlowski PTAL when you next have a chance

[nklaassen]

sorry, misclicked on mobile.. will review

[nklaassen]

LGTM

[github-actions]

@ibeckermayer See the table below for backport results.

Branch	Result
branch/v10	Create PR
branch/v9	Create PR