add bypass support for server nodes

bypass.go

 package gost
 
 import (
+	"bytes"
+	"fmt"
 	"net"
 
 	glob "github.com/gobwas/glob"
@@ -10,6 +12,7 @@ import (
 // it gives the match result of the given pattern for specific v.
 type Matcher interface {
 	Match(v string) bool
+	String() string
 }
 
 // NewMatcher creates a Matcher for the given pattern.
@@ -48,6 +51,10 @@ func (m *ipMatcher) Match(ip string) bool {
 	return m.ip.Equal(net.ParseIP(ip))
 }
 
+func (m *ipMatcher) String() string {
+	return "ip " + m.ip.String()
+}
+
 type cidrMatcher struct {
 	ipNet *net.IPNet
 }
@@ -66,8 +73,13 @@ func (m *cidrMatcher) Match(ip string) bool {
 	return m.ipNet.Contains(net.ParseIP(ip))
 }
 
+func (m *cidrMatcher) String() string {
+	return "cidr " + m.ipNet.String()
+}
+
 type domainMatcher struct {
-	glob glob.Glob
+	pattern string
+	glob    glob.Glob
 }
 
 // DomainMatcher creates a Matcher for a specific domain pattern,
@@ -75,7 +87,8 @@ type domainMatcher struct {
 // or a wildcard such as '*.exmaple.com'.
 func DomainMatcher(pattern string) Matcher {
 	return &domainMatcher{
-		glob: glob.MustCompile(pattern),
+		pattern: pattern,
+		glob:    glob.MustCompile(pattern),
 	}
 }
 
@@ -86,6 +99,10 @@ func (m *domainMatcher) Match(domain string) bool {
 	return m.glob.Match(domain)
 }
 
+func (m *domainMatcher) String() string {
+	return "domain " + m.pattern
+}
+
 // Bypass is a filter for address (IP or domain).
 // It contains a list of matchers.
 type Bypass struct {
@@ -116,15 +133,45 @@ func NewBypassPatterns(patterns []string, reverse bool) *Bypass {
 
 // Contains reports whether the bypass includes addr.
 func (bp *Bypass) Contains(addr string) bool {
+	if bp == nil {
+		return false
+	}
+
+	var matched bool
 	for _, matcher := range bp.matchers {
 		if matcher == nil {
 			continue
 		}
-		matched := matcher.Match(addr)
-		if (matched && !bp.reverse) ||
-			(!matched && bp.reverse) {
-			return true
+		if matcher.Match(addr) {
+			matched = true
+			break
 		}
 	}
-	return false
+	return !bp.reverse && matched ||
+		bp.reverse && !matched
+}
+
+// AddMatchers appends matchers to the bypass matcher list.
+func (bp *Bypass) AddMatchers(matchers ...Matcher) {
+	bp.matchers = append(bp.matchers, matchers...)
+}
+
+// Matchers return the bypass matcher list.
+func (bp *Bypass) Matchers() []Matcher {
+	return bp.matchers
+}
+
+// Reversed reports whether the rules of the bypass are reversed.
+func (bp *Bypass) Reversed() bool {
+	return bp.reverse
+}
+
+func (bp *Bypass) String() string {
+	b := &bytes.Buffer{}
+	fmt.Fprintf(b, "reversed: %v\n", bp.Reversed())
+	for _, m := range bp.Matchers() {
+		b.WriteString(m.String())
+		b.WriteByte('\n')
+	}
+	return b.String()
 }

cmd/gost/main.go

@@ -484,7 +484,15 @@ func (r *route) serve() error {
 			}
 		}
 
+		fBypass := node.Get("bypass")
+		if fBypass == "" {
+			fBypass = "bypass" // default bypass file
+		}
+
 		srv := &gost.Server{Listener: ln}
+		srv.Init(
+			gost.BypassServerOption(parseBypass(fBypass)),
+		)
 		go srv.Serve(handler)
 	}
 
@@ -685,3 +693,29 @@ func parseStrategy(s string) gost.Strategy {
 
 	}
 }
+
+func parseBypass(fpath string) (bypass *gost.Bypass) {
+	if fpath == "" {
+		return
+	}
+	f, err := os.Open(fpath)
+	if err != nil {
+		return
+	}
+
+	var matchers []gost.Matcher
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if n := strings.IndexByte(line, '#'); n >= 0 {
+			line = line[:n]
+		}
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		matchers = append(matchers, gost.NewMatcher(line))
+	}
+	bypass = gost.NewBypass(matchers, strings.HasPrefix(fpath, "~"))
+	return
+}

server.go

@@ -11,6 +11,17 @@ import (
 // Server is a proxy server.
 type Server struct {
 	Listener Listener
+	options  *ServerOptions
+}
+
+// Init intializes server with given options.
+func (s *Server) Init(opts ...ServerOption) {
+	if s.options == nil {
+		s.options = &ServerOptions{}
+	}
+	for _, opt := range opts {
+		opt(s.options)
+	}
 }
 
 // Addr returns the address of the server
@@ -24,7 +35,9 @@ func (s *Server) Close() error {
 }
 
 // Serve serves as a proxy server.
-func (s *Server) Serve(h Handler) error {
+func (s *Server) Serve(h Handler, opts ...ServerOption) error {
+	s.Init(opts...)
+
 	if s.Listener == nil {
 		ln, err := TCPListener("")
 		if err != nil {
@@ -57,9 +70,31 @@ func (s *Server) Serve(h Handler) error {
 			return e
 		}
 		tempDelay = 0
+
+		ip := extractIP(conn.RemoteAddr())
+		if s.options.Bypass.Contains(ip.String()) {
+			log.Log("bypass", ip.String())
+			conn.Close()
+			continue
+		}
+
 		go h.Handle(conn)
 	}
+}
+
+// ServerOptions holds the options for Server.
+type ServerOptions struct {
+	Bypass *Bypass
+}
+
+// ServerOption allows a common way to set server options.
+type ServerOption func(opts *ServerOptions)
 
+// BypassServerOption sets the bypass option of ServerOptions.
+func BypassServerOption(bypass *Bypass) ServerOption {
+	return func(opts *ServerOptions) {
+		opts.Bypass = bypass
+	}
 }
 
 // Listener is a proxy server listener, just like a net.Listener.
@@ -116,3 +151,16 @@ func transport(rw1, rw2 io.ReadWriter) error {
 	}
 	return err
 }
+
+func extractIP(addr net.Addr) net.IP {
+	switch v := addr.(type) {
+	case *net.IPAddr:
+		return v.IP
+	case *net.TCPAddr:
+		return v.IP
+	case *net.UDPAddr:
+		return v.IP
+	default:
+	}
+	return net.IPv4zero
+}