a lightweight dns-over-tls proxy (WIP)

Not ready for production

• Basic functionality (accept query from UDP/TCP -> resolve query through dns-over-tls protocol -> forward answer to users)
• Reuse connection to prevent unnecessary handshake
• Select fastest remote dynamically
• Parallel resolve all queries
• Resolve query via mutliple remote servers (when idle)
• SSL session cache
• rfc7828 The edns-tcp-keepalive EDNS0 Option
• rfc7871 Client Subnet in DNS Queries
• rfc7830 The EDNS(0) Padding Option
• Cache
• Support TCP/UDP foreign server
• Select foreign server by rule

https://en.wikipedia.org/wiki/DNS_over_TLS

https://developers.cloudflare.com/1.1.1.1/dns-over-tls/

https://developers.google.com/speed/public-dns/docs/dns-over-tls