Due to a copy/paste-o, we were monitoring address changes twice, and
not monitoring route changes at all.
Verified with 'tailscale debug --monitor' that this actually works now (while
running 'route add 10.3.0.0 mask 255.255.0.0 10.0.0.1' and 'route delete (same)'
back and forth in cmd.exe)
In practice route changes are accompanied by address changes and this
doesn't fix any known issues. I just noticed this while reading this
code again. But at least the code does what it was trying to do now.
Turns out for the particular error I was chasing, it actually returns
200 and zero data. But this code mirrors the same check in the map
poll, and is the right thing to do in the name of future debugging.
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
This function is only called in fake mode, which won't do anything more
with the packet after we respond to it anyway, so dropping it in the
prefilter is not necessary. And it's kinda semantically wrong: we did
not reject it, so telling the upper layer that it was rejected produces
an ugly error message.
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
At some point faketun got implemented as a loopback (put a packet in
from wireguard, the same packet goes back to wireguard) which is not
useful. It's supposed to be an interface that just sinks all packets,
and then wgengine adds *only* and ICMP Echo responder as a layer on
top.
This caused extremely odd bugs on darwin, where the special case that
reinjects packets from local->local was filling the loopback channel
and creating an infinite loop (which became jammed since the reader and
writer were in the same goroutine).
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
If no interfaces are up, calm down and stop spamming so much. It was
noticed as especially bad on Windows, but probably was bad
everywhere. I just have the best network conditions testing on a
Windows VM.
Updates #604
This makes it easy to compact slices that contain duplicate elements
by sorting and then uniqing.
This is an alternative to constructing an intermediate map
and then extracting elements from it. It also provides
more control over equality than using a map key does.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
So previous routes aren't shadowing resources that the operating
system might need (Windows Domain Controller, DNS server, corp HTTP
proxy, WinHTTP fetching the PAC file itself, etc).
This effectively detects when we're transitioning from, say, public
wifi to corp wifi and makes Tailscale remove all its routes and stops
its TCP connections and tries connecting to everything anew.
Updates tailscale/corp#653
Not used for anything yet (except logging), but populate the current
proxy autoconfig PAC URL in Interfaces.State.
A future change will do things based on it.
Gracefully skips touching the v6 NAT table on systems that don't have
it, and doesn't configure IPv6 at all if IPv6 is globally disabled.
Signed-off-by: David Anderson <danderson@tailscale.com>
When the network link changes, existing UDP sockets fail immediately
and permanently on macOS.
The forwarder set up a single UDP conn and never changed it.
As a result, any time there was a network link change,
all forwarded DNS queries failed.
To fix this, create a new connection when send requests
fail because of network unreachability.
This change is darwin-only, although extended it to other platforms
should be straightforward.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
While we're here, parseQuery into a plain function.
This is helpful for fuzzing. (Which I did a bit of. Didn't find anything.)
And clean up a few minor things.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
