1. add comments, 2. optimize text message

router/dns.go

@@ -16,6 +16,7 @@ func (r *Router) ServeDNS(w dns.ResponseWriter, req *dns.Msg) {
 	}
 
 	domain := req.Question[0].Name
+	// 1. rule_based( block > direct > proxy )
 	switch {
 	case r.blockRule.Match(domain):
 		_ = w.WriteMsg(r.dnsFail(req, dns.RcodeNameError))
@@ -28,6 +29,7 @@ func (r *Router) ServeDNS(w dns.ResponseWriter, req *dns.Msg) {
 		return
 	}
 
+	// 2. direct with cache, do not fallback to proxy to avoid side-effect
 	c := &dnsCache{Router: r, Req: req}
 	if err := r.dns.cache.Remember(c, req.Question[0].String()); err != nil {
 		_ = w.WriteMsg(r.dnsFail(req, dns.RcodeServerFailure))

router/ping.go

@@ -30,6 +30,7 @@ type ping struct {
 }
 
 func (p *ping) Fulfill(key string) error {
+	// just like `curl -I http://domain.com:80`
 	_, err := pingClient.Head(net.JoinHostPort(key, "80"))
 	deferlog.Std.DebugWarn(err).
 		Str("domain", key).

router/router.go

@@ -107,6 +107,9 @@ func (r *Router) RouteHandle(conn net.Conn, domain string, port uint16) (err err
 
 	addr := net.JoinHostPort(domain, strconv.FormatUint(uint64(port), 10))
 
+	// 1. rule_based( block > direct > proxy )
+	// 2. detect_based( CN IP || access site )
+	// 3. fallback( proxy )
 	switch {
 	case r.blockRule.Match(domain):
 		return nil
@@ -117,9 +120,7 @@ func (r *Router) RouteHandle(conn net.Conn, domain string, port uint16) (err err
 	case r.proxyRule.Match(domain):
 		return r.ProxyHandle(conn, domain, port)
 
-	case r.localSite(domain):
-		return r.DirectHandle(conn, addr)
-	case r.isAccess(domain, port):
+	case r.localSite(domain), r.isAccess(domain, port):
 		return r.DirectHandle(conn, addr)
 	default:
 		return r.ProxyHandle(conn, domain, port)