transport: add vaydns

[bloodflow3r]

Adds VayDNS as a new transport alongside the existing dnstt transport. Client-side only. Can be used with any outbound protocol.

VayDNS is a dnstt fork with additional features: per-query UDP sockets, forged response filtering, rate limiting, QNAME constraints, configurable timeouts, and dnstt wire compatibility mode.

Config

{
  "outbounds": [
    {
      "protocol": "socks",
      "settings": {
        "servers": [{"address": "1.1.1.1", "port": 53}]
      },
      "streamSettings": {
        "network": "vaydns",
        "vaydnsSettings": {
          "serverPublicKey": "hex-encoded-pubkey",
          "serverAddress": "t.example.com",
          "rps": 200,
          "maxNumLabels": 2
        }
      }
    }
  ]
}

Available settings

Field	Type	Description	Default
serverPublicKey	string	Server public key (hex)	required
serverAddress	string	Tunnel domain	required
resolverType	string	Resolver type (udp)	udp
dnsttCompat	bool	Use original dnstt wire format	false
clientidSize	int	ClientID size in bytes	2
maxQnameLen	int	Max QNAME wire length	101 (253 with dnsttCompat)
maxNumLabels	int	Max data labels (sub-domains before tunnel domain)	0 (unlimited)
rps	float	DNS query rate limit per second	0 (unlimited)
idleTimeout	string	Session idle timeout	10s (2m with dnsttCompat)
keepalive	string	Keepalive ping interval	2s (10s with dnsttCompat)
maxStreams	int	Max concurrent streams	256
udpWorkers	int	Concurrent UDP workers	100
udpTimeout	string	Per-query UDP timeout	400ms
udpSharedSocket	bool	Use single shared UDP socket	false
udpAcceptErrors	bool	Pass through DNS error responses	false

Only serverPublicKey and serverAddress are required. All other fields use sensible defaults.