Instead of re-query DNS record for upstream when re-bootstrapping, just
query all records on startup, then selecting the next bootstrap ip
depends on the current network stack.
For better recovery and dealing with network stack changes, this commit
change the request flow to:
failure of any kind -> recreate transport/re-bootstrap -> retry once
That would make ctrld recover from all scenarios in theory.
At startup, ctrld gathers bootstrap IP information and use this
bootstrap IP for connecting to upstream. However, in case the network
stack changed, for example, dues to VPN connection, ctrld will still use
this old (maybe invalid) bootstrap IP for the current network stack.
This commit rework the discovering process, and re-initializing the
bootstrap IP if connecting to upstream failed.
Supported actions:
- start: install and start ctrld as a system service
- stop: stop the ctrld service
- restart: restart ctrld service
- status: show status of ctrld service
- uninstall: remove ctrld from system service
This commit adds the ability to start `ctrld` without config file. All
necessary information can be provided via command line flags, either in
base64 encoded config or launch arguments.
This commit adds config params to enable local DNS response caching and
control its behavior, allow tweaking the cache size, ttl override and
serving stale response.
Previously, for each DoH query, we use the net/http default transport
with DialContext function re-assigned. This has some problems:
- The first query to server will be slow.
- Using the default transport for all upstreams can have race condition
in case of multiple queries to multiple DoH upstreams
This commit fixes those issues, by initializing a separate transport for
each DoH upstream, the warming up the transport by doing a test query.
Later queries can take the advantage and re-use the connection.
