Due to iOS memory limitations in 2020 (see
https://tailscale.com/blog/go-linker, etc) and wireguard-go using
multiple goroutines per peer, commit 16a9cfe2f4 introduced some
convoluted pathsways through Tailscale to look at packets before
they're delivered to wireguard-go and lazily reconfigure wireguard on
the fly before delivering a packet, only telling wireguard about peers
that are active.
We eventually want to remove that code and integrate wireguard-go's
configuration with Tailscale's existing netmap tracking.
To make it easier to find that code later, this makes it modular. It
saves 12 KB (of disk) to turn it off (at the expense of lots of RAM),
but that's not really the point. The point is rather making it obvious
(via the new constants) where this code even is.
Updates #12614
Change-Id: I113b040f3e35f7d861c457eaa710d35f47cee1cb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
I'd started to do this in the earlier ts_omit_server PR but
decided to split it into this separate PR.
Updates #17128
Change-Id: Ief8823a78d1f7bbb79e64a5cab30a7d0a5d6ff4b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This renames the package+symbols in the earlier 17ffa80138 to be
in their own package ("buildfeatures") and start with the word "Has"
like "if buildfeatures.HasFoo {".
Updates #12614
Change-Id: I510e5f65993e5b76a0e163e3aa4543755213cbf6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
So code (in upcoming PRs) can test for the build tags with consts and
get dead code elimination from the compiler+linker.
Updates #12614
Change-Id: If6160453ffd01b798f09894141e7631a93385941
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Brad Fitzpatrick