1. add comments, 2. optimize text message

cmd/sower/main.go

@@ -26,7 +26,7 @@ var (
 
 	conf = struct {
 		Remote struct {
-			Type     string `default:"sower" required:"true" usage:"optional: sower/trojan/socks5"`
+			Type     string `default:"sower" required:"true" usage:"option: sower/trojan/socks5"`
 			Addr     string `required:"true" usage:"proxy address, eg: proxy.com/127.0.0.1:7890"`
 			Password string `usage:"remote proxy password"`
 		}
@@ -44,24 +44,24 @@ var (
 		Router struct {
 			Block struct {
 				File       string   `usage:"block list file, local file or remote"`
-				FilePrefix string   `default:"**." usage:"parsed as 'prefix.line_text'"`
+				FilePrefix string   `default:"**." usage:"parsed as '<prefix>line_text'"`
 				Rules      []string `usage:"block list rules"`
 			}
 			Direct struct {
 				File       string   `usage:"direct list file, local file or remote"`
-				FilePrefix string   `default:"**." usage:"parsed as 'prefix.line_text'"`
+				FilePrefix string   `default:"**." usage:"parsed as '<prefix>line_text'"`
 				Rules      []string `usage:"direct list rules"`
 			}
 			Proxy struct {
 				File       string   `usage:"proxy list file, local file or remote"`
-				FilePrefix string   `default:"**." usage:"parsed as 'prefix.line_text'"`
+				FilePrefix string   `default:"**." usage:"parsed as '<prefix>line_text'"`
 				Rules      []string `usage:"proxy list rules"`
 			}
 
 			Country struct {
 				MMDB       string   `usage:"mmdb file"`
 				File       string   `usage:"CIDR block list file, local file or remote"`
-				FilePrefix string   `default:"" usage:"parsed as 'prefix.line_text'"`
+				FilePrefix string   `default:"" usage:"parsed as '<prefix>line_text'"`
 				Rules      []string `usage:"CIDR list rules"`
 			}
 		}
@@ -117,11 +117,10 @@ func main() {
 		}
 		go ServeHTTPS(lnHTTPS, r)
 
-		addr := net.JoinHostPort(conf.DNS.Serve, "53")
 		log.Info().
-			Str("listen_on", addr).
+			Str("listen_on", conf.DNS.Serve).
 			Msg("DNS proxy started")
-		if err := dns.ListenAndServe(addr, "udp", r); err != nil {
+		if err := dns.ListenAndServe(net.JoinHostPort(conf.DNS.Serve, "53"), "udp", r); err != nil {
 			log.Fatal().Err(err).Msg("serve dns")
 		}
 	}()

cmd/sowerd/main.go

@@ -119,6 +119,7 @@ func serve443(ln net.Listener, fakeSite string, sower *sower.Sower, trojan *troj
 			Msgf("relay conn to %s", addr)
 	}()
 
+	// 1. detect if it's a sower underlaying connection
 	teeconn.Reread()
 	if addr, err = sower.Unwrap(teeconn); err == nil {
 		teeconn.Stop()
@@ -127,6 +128,7 @@ func serve443(ln net.Listener, fakeSite string, sower *sower.Sower, trojan *troj
 		return
 	}
 
+	// 2. detect if it's a trojan underlaying connection
 	teeconn.Reread()
 	if addr, err = trojan.Unwrap(teeconn); err == nil {
 		teeconn.Stop()
@@ -135,6 +137,7 @@ func serve443(ln net.Listener, fakeSite string, sower *sower.Sower, trojan *troj
 		return
 	}
 
+	// 3. fallback to fake site
 	teeconn.Stop().Reread()
 	dur, err = util.RelayTo(teeconn, fakeSite)
 }

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)