Saves 139 KB.
Also Synology support, which I saw had its own large-ish proxy parsing
support on Linux, but support for proxies without Synology proxy
support is reasonable, so I pulled that out as its own thing.
Updates #12614
Change-Id: I22de285a3def7be77fdcf23e2bec7c83c9655593
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
In prep for most of the package funcs in net/interfaces to become
methods in a long-lived netmon.Monitor that can cache things. (Many
of the funcs are very heavy to call regularly, whereas the long-lived
netmon.Monitor can subscribe to things from the OS and remember
answers to questions it's asked regularly later)
Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299
Change-Id: Ie4e8dedb70136af2d611b990b865a822cd1797e5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>