When bootstrapping, if the network changed, for example, firewall rules
changed during VPN connection, the bootstrap IPs may not be resolved, so
ctrld won't work. Since bootstrap IPs is necessary for ctrld to work
properly, we should wait until we can resolve upstream IP before we can
start serving requests.
Instead of always doubling the request, first we wrap the request with a
failover timeout, 500ms, which is an average time for a normal request.
If this request failed, trigger re-bootstrapping and retry the request.
When network changes, for example: connect/disconnect VPN, the old
connection will become broken, but still can be re-used for new
requests. That would cause un-necessary delay for ctrld clients:
- Time 0 - do request with broken transport, 5s timeout.
- Time 0.5 - network stack become usable.
- Time 5 - timeout reached.
- Time 5.1 - do request with new transport -> success.
Instead, we can do two requests in parallel, with the failover one using
a fresh new transport. So if the main one is broken, we still can get
the result from the failover one.
We see in practice on fresh new VM test, there's a DNS server that
return the answer with record not for the query domain.
To workaround this, filter out the answers not for the query domain.
This reverts commit 00fe7f59d13774f2ea6c325bdbb8165be58a1edd.
The purpose is disable cd mode for already installed service, which is
a hard problem than we thought. So leave it out of v1.2 cycle.
When writing default config file, the content must be marshalled to the
config object first before writing to disk.
While at it, also use full path for default config file to make it clear
to the user where the config is written.
This commit add the ability for ctrld to gather client information,
including mac/ip/hostname, and send to Control-D server through a
config per upstream.
- Add send_client_info upstream config.
- Read/Watch dnsmasq leases files on supported platforms.
- Add corresponding client info to DoH query header
All of these only apply for Control-D upstream, though.
So we don't have to depend on network stack probing to decide whether
ipv4 or ipv6 will be used.
While at it, also prevent a race report when doing the same parallel
resolving for os resolver, even though this race is harmless.
Otherwise, we experiment with ctrld slow start after rebooting, because
the network check continuously report failed status even the network
state is up. Restoring the DNS before stopping, we leave the network
state as default, as long as ctrld starts, the DNS is configured again.
