implement WithDialerControl

examples/simple/main.go

@@ -26,12 +26,18 @@ var (
 
 func main() {
 	flag.Parse()
-	serverOpts := make([]corebgp.ServerOption, 0)
+	var (
+		lis net.Listener
+		err error
+	)
 	if len(*bindAddr) > 0 {
-		serverOpts = append(serverOpts, corebgp.LocalAddrs([]string{*bindAddr}))
+		lis, err = net.Listen("tcp", *bindAddr)
+		if err != nil {
+			log.Fatalf("error constructing listener: %v", err)
+		}
 	}
 	corebgp.SetLogger(log.Print)
-	srv, err := corebgp.NewServer(net.ParseIP(*routerID), serverOpts...)
+	srv, err := corebgp.NewServer(net.ParseIP(*routerID))
 	if err != nil {
 		log.Fatalf("error constructing server: %v", err)
 	}
@@ -52,7 +58,7 @@ func main() {
 
 	srvErrCh := make(chan error)
 	go func() {
-		err := srv.Serve()
+		err := srv.Serve([]net.Listener{lis})
 		srvErrCh <- err
 	}()
 

fsm.go

@@ -223,6 +223,7 @@ func (f *fsm) dialPeer() {
 		}
 		dialer := &net.Dialer{
 			LocalAddr: laddr,
+			Control:   f.peer.options.dialerControlFn,
 		}
 		conn, err := dialer.DialContext(ctx, "tcp",
 			net.JoinHostPort(f.peer.config.RemoteAddress.String(),

peer_options.go

@@ -2,6 +2,7 @@ package corebgp
 
 import (
 	"errors"
+	"syscall"
 	"time"
 )
 
@@ -11,6 +12,7 @@ type peerOptions struct {
 	connectRetryTime time.Duration
 	port             int
 	passive          bool
+	dialerControlFn  func(network, address string, c syscall.RawConn) error
 }
 
 func (p peerOptions) validate() error {
@@ -98,3 +100,13 @@ func WithPort(p int) PeerOption {
 		o.port = p
 	})
 }
+
+// WithDialerControl returns a PeerOption that sets the outbound net.Dialer
+// Control field. This is commonly used to set socket options, e.g. ip TTL, tcp
+// md5, tcp_nodelay, etc...
+func WithDialerControl(fn func(network, address string,
+	c syscall.RawConn) error) PeerOption {
+	return newFuncPeerOption(func(o *peerOptions) {
+		o.dialerControlFn = fn
+	})
+}

server.go

@@ -10,10 +10,9 @@ import (
 
 // Server is a BGP server that manages peers.
 type Server struct {
-	mu      sync.Mutex
-	id      uint32
-	peers   map[string]*peer
-	options serverOptions
+	mu    sync.Mutex
+	id    uint32
+	peers map[string]*peer
 
 	// control channels & run state
 	serving       bool
@@ -23,26 +22,16 @@ type Server struct {
 }
 
 // NewServer creates a new Server.
-func NewServer(routerID net.IP, opts ...ServerOption) (*Server, error) {
+func NewServer(routerID net.IP) (*Server, error) {
 	v4 := routerID.To4()
 	if v4 == nil {
 		return nil, errors.New("invalid router ID")
 	}
 
-	o := defaultServerOptions()
-	for _, opt := range opts {
-		opt.apply(&o)
-	}
-	err := o.validate()
-	if err != nil {
-		return nil, err
-	}
-
 	s := &Server{
 		mu:            sync.Mutex{},
 		id:            binary.BigEndian.Uint32(v4),
 		peers:         make(map[string]*peer),
-		options:       o,
 		doneServingCh: make(chan struct{}),
 		closeCh:       make(chan struct{}),
 	}
@@ -54,10 +43,10 @@ var (
 	ErrPeerNotExist = errors.New("peer does not exist")
 )
 
-// Serve starts all peers' FSMs, binds to local sockets for incoming connection
-// handling (if Server was created with LocalAddrs), and then blocks. Serve
-// returns ErrServerClosed upon Close() or a listener/bind error if one occurs.
-func (s *Server) Serve() error {
+// Serve starts all peers' FSMs, starts handling incoming connections if a
+// non-nil listener is provided, and then blocks. Serve returns ErrServerClosed
+// upon Close() or a listener error if one occurs.
+func (s *Server) Serve(listeners []net.Listener) error {
 	s.mu.Lock()
 	// check if server has been closed
 	select {
@@ -88,18 +77,7 @@ func (s *Server) Serve() error {
 		s.mu.Unlock()
 	}()
 
-	// construct and bind listeners
 	lisErrCh := make(chan error)
-	listeners := make([]net.Listener, 0)
-	for laddr := range s.options.localAddrs {
-		lis, err := net.Listen("tcp", laddr)
-		if err != nil {
-			return err
-		}
-		defer lis.Close()
-		listeners = append(listeners, lis)
-	}
-
 	lisWG := &sync.WaitGroup{}
 	closingListeners := make(chan struct{})
 	for _, lis := range listeners {

test/bird_test.go

@@ -162,9 +162,7 @@ func TestCleanBGPSession(t *testing.T) {
 		event:                eventCh,
 	}
 
-	opts := make([]corebgp.ServerOption, 0)
-	opts = append(opts, corebgp.LocalAddrs([]string{fmt.Sprintf("%s:179", myAddress)}))
-	server, err := corebgp.NewServer(net.ParseIP(myAddress), opts...)
+	server, err := corebgp.NewServer(net.ParseIP(myAddress))
 	if err != nil {
 		t.Fatalf("error constructing server: %v", err)
 	}
@@ -184,7 +182,12 @@ func TestCleanBGPSession(t *testing.T) {
 	// enable BGP session on BIRD side
 	birdControl(t, "enable corebgp")
 
-	go server.Serve() // nolint: errcheck
+	lis, err := net.Listen("tcp", net.JoinHostPort(myAddress, "179"))
+	if err != nil {
+		t.Fatalf("error constructing listener: %v", err)
+	}
+	defer lis.Close()
+	go server.Serve([]net.Listener{lis}) // nolint: errcheck
 	defer server.Close()
 
 	// verify GetCapabilities
@@ -365,9 +368,7 @@ func TestNotificationSentOnOpen(t *testing.T) {
 		event:                eventCh,
 	}
 
-	opts := make([]corebgp.ServerOption, 0)
-	opts = append(opts, corebgp.LocalAddrs([]string{fmt.Sprintf("%s:179", myAddress)}))
-	server, err := corebgp.NewServer(net.ParseIP(myAddress), opts...)
+	server, err := corebgp.NewServer(net.ParseIP(myAddress))
 	if err != nil {
 		t.Fatalf("error constructing server: %v", err)
 	}
@@ -387,7 +388,12 @@ func TestNotificationSentOnOpen(t *testing.T) {
 	// enable BGP session on BIRD side
 	birdControl(t, "enable corebgp")
 
-	go server.Serve() // nolint: errcheck
+	lis, err := net.Listen("tcp", net.JoinHostPort(myAddress, "179"))
+	if err != nil {
+		t.Fatalf("error constructing listener: %v", err)
+	}
+	defer lis.Close()
+	go server.Serve([]net.Listener{lis}) // nolint: errcheck
 	defer server.Close()
 
 	// expect get caps event
@@ -451,9 +457,7 @@ func TestNotificationSentOnUpdate(t *testing.T) {
 		event:                eventCh,
 	}
 
-	opts := make([]corebgp.ServerOption, 0)
-	opts = append(opts, corebgp.LocalAddrs([]string{fmt.Sprintf("%s:179", myAddress)}))
-	server, err := corebgp.NewServer(net.ParseIP(myAddress), opts...)
+	server, err := corebgp.NewServer(net.ParseIP(myAddress))
 	if err != nil {
 		t.Fatalf("error constructing server: %v", err)
 	}
@@ -473,7 +477,12 @@ func TestNotificationSentOnUpdate(t *testing.T) {
 	// enable BGP session on BIRD side
 	birdControl(t, "enable corebgp")
 
-	go server.Serve() // nolint: errcheck
+	lis, err := net.Listen("tcp", net.JoinHostPort(myAddress, "179"))
+	if err != nil {
+		t.Fatalf("error constructing listener: %v", err)
+	}
+	defer lis.Close()
+	go server.Serve([]net.Listener{lis}) // nolint: errcheck
 	defer server.Close()
 
 	// expect get caps event