control/controlhttp: don't assume port 80 upgrade response will work

Browse Source

Just because we get an HTTP upgrade response over port 80, don't
assume we'll be able to do bi-di Noise over it. There might be a MITM
corp proxy or anti-virus/firewall interfering. Do a bit more work to
validate the connection before proceeding to give up on the TLS port
443 dial.

Updates #4557 (probably fixes)

Change-Id: I0e1bcc195af21ad3d360ffe79daead730dfd86f1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

...

This commit is contained in:

500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f