The definition of winHTTPProxyInfo was using the wrong type (uint16 vs uint32)
for its first field. I fixed that type.
Furthermore, any UTF16 strings returned in that structure must be explicitly
freed. I added code to do this.
Finally, since this is the second time I've seen type safety errors in this code,
I switched the native API calls over to use wrappers generated by mkwinsyscall.
I know that would not have helped prevent the previous two problems, but every
bit helps IMHO.
Updates https://github.com/tailscale/tailscale/issues/4811
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The best flag to use on Win7 and Win8.0 is deprecated in Win8.1, so we resolve
the flag depending on OS version info.
Fixes https://github.com/tailscale/tailscale/issues/4201
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The Windows BOOL type is an int32. We were using a bool,
which is a one byte wide. This could be responsible for the
ERROR_INVALID_PARAMETER errors we were seeing for calls to
WinHttpGetProxyForUrl.
We manually checked all other existing Windows syscalls
for similar mistakes and did not find any.
Updates #879
Co-authored-by: Aaron Klotz <aaron@tailscale.com>
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
We often see things in logs like:
2021-03-02 17:52:45.2456258 +0800 +0800: winhttp: Open: The parameter is incorrect.
2021-03-02 17:52:45.2506261 +0800 +0800: tshttpproxy: winhttp: GetProxyForURL("https://log.tailscale.io/c/tailnode.log.tailscale.io/5037bb42f4bc330e2d6143e191a7ff7e837c6be538139231de69a439536e0d68"): ERROR_INVALID_PARAMETER [unexpected]
I have a hunch that WinHTTP has thread-local state. If so, this would fix it.
If not, this is pretty harmless.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Otherwise log upload HTTP requests generate proxy errrors which
generate logs which generate HTTP requests which generate proxy
errors which generate more logs, etc.
Fixes#879
Otherwise when PAC server is down, we log, and each log entry is a new
HTTP request (from logtail) and a new GetProxyForURL call, which again
logs, non-stop. This is also nicer to the WinHTTP service.
Then also hook up link change notifications to the cache to reset it
if there's a chance the network might work sooner.
We currently have a chickend-and-egg situation in some environments
where we can set up routes that WinHTTP's WPAD/PAC resolution service
needs to download the PAC file to evaluate GetProxyForURL, but the PAC
file is behind a route for which we need to call GetProxyForURL to
e.g. dial a DERP server.
As a short-term fix, just assume that the most recently returned proxy
is good enough for such situations.
