Implement websocket (ws:// and wss://) listeners

Signed-off-by: Vasyl Gello <vasek.gello@gmail.com>

src/core/link_wss.go

@@ -0,0 +1,132 @@
+package core
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/Arceliar/phony"
+	"nhooyr.io/websocket"
+)
+
+type linkWSS struct {
+	phony.Inbox
+	tlsconfig *tls.Config
+	*links
+}
+
+type linkWSSConn struct {
+	net.Conn
+}
+
+type linkWSSListener struct {
+	ch          chan *linkWSSConn
+	ctx         context.Context
+	httpServer  *http.Server
+	listener    net.Listener
+	tlslistener net.Listener
+}
+
+type wssServer struct {
+	ch  chan *linkWSSConn
+	ctx context.Context
+}
+
+func (l *linkWSSListener) Accept() (net.Conn, error) {
+	qs := <-l.ch
+	if qs == nil {
+		return nil, context.Canceled
+	}
+	return qs, nil
+}
+
+func (l *linkWSSListener) Addr() net.Addr {
+	return l.listener.Addr()
+}
+
+func (l *linkWSSListener) Close() error {
+	if err := l.httpServer.Shutdown(l.ctx); err != nil {
+		return err
+	}
+	if err := l.tlslistener.Close(); err != nil {
+		return err
+	}
+	return l.listener.Close()
+}
+
+func (s *wssServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	c, err := websocket.Accept(w, r, &websocket.AcceptOptions{
+		Subprotocols: []string{"ygg-ws"},
+	})
+
+	if err != nil {
+		return
+	}
+
+	if c.Subprotocol() != "ygg-ws" {
+		c.Close(websocket.StatusPolicyViolation, "client must speak the ygg-ws subprotocol")
+		return
+	}
+
+	netconn := websocket.NetConn(s.ctx, c, websocket.MessageBinary)
+
+	ch := s.ch
+	ch <- &linkWSSConn{
+		Conn: netconn,
+	}
+}
+
+func (l *links) newLinkWSS() *linkWSS {
+	lwss := &linkWSS{
+		links:     l,
+		tlsconfig: l.core.config.tls.Clone(),
+	}
+
+	return lwss
+}
+
+func (l *linkWSS) dial(ctx context.Context, url *url.URL, info linkInfo, options linkOptions) (net.Conn, error) {
+	wsconn, _, err := websocket.Dial(ctx, url.String(), &websocket.DialOptions{
+		Subprotocols: []string{"ygg-ws"},
+	})
+	if err != nil {
+		return nil, err
+	}
+	netconn := websocket.NetConn(ctx, wsconn, websocket.MessageBinary)
+	return &linkWSSConn{
+		Conn: netconn,
+	}, nil
+}
+
+func (l *linkWSS) listen(ctx context.Context, url *url.URL, _ string) (net.Listener, error) {
+	nl, err := net.Listen("tcp", url.Host)
+	if err != nil {
+		return nil, err
+	}
+
+	tl := tls.NewListener(nl, l.tlsconfig)
+
+	ch := make(chan *linkWSSConn)
+
+	httpServer := &http.Server{
+		Handler: &wssServer{
+			ch:  ch,
+			ctx: ctx,
+		},
+		ReadTimeout:  time.Second * 10,
+		WriteTimeout: time.Second * 10,
+	}
+
+	lwl := &linkWSSListener{
+		ch:          ch,
+		ctx:         ctx,
+		httpServer:  httpServer,
+		listener:    nl,
+		tlslistener: tl,
+	}
+	go lwl.httpServer.Serve(tl)
+	return lwl, nil
+}