Add initial relay code

relay/server/server.go

@@ -0,0 +1,149 @@
+package server
+
+import (
+	"fmt"
+	"io"
+	"net"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/relay/messages"
+	"github.com/netbirdio/netbird/relay/server/listener"
+	"github.com/netbirdio/netbird/relay/server/listener/ws"
+)
+
+// Server
+// todo:
+// authentication: provide JWT token via RPC call. The MGM server can forward the token to the agents.
+// connection timeout handling
+// implement HA (High Availability) mode
+type Server struct {
+	store *Store
+
+	listener listener.Listener
+}
+
+func NewServer() *Server {
+	return &Server{
+		store: NewStore(),
+	}
+}
+
+func (r *Server) Listen(address string) error {
+	r.listener = ws.NewListener(address)
+	return r.listener.Listen(r.accept)
+}
+
+func (r *Server) Close() error {
+	if r.listener == nil {
+		return nil
+	}
+	return r.listener.Close()
+}
+
+func (r *Server) accept(conn net.Conn) {
+	peer, err := handShake(conn)
+	if err != nil {
+		log.Errorf("failed to handshake wiht %s: %s", conn.RemoteAddr(), err)
+		cErr := conn.Close()
+		if cErr != nil {
+			log.Errorf("failed to close connection, %s: %s", conn.RemoteAddr(), cErr)
+		}
+		return
+	}
+	peer.Log.Debugf("on new connection: %s", conn.RemoteAddr())
+
+	r.store.AddPeer(peer)
+	defer func() {
+		peer.Log.Debugf("teardown connection")
+		r.store.DeletePeer(peer)
+	}()
+
+	buf := make([]byte, 65535) // todo: optimize buffer size
+	for {
+		n, err := conn.Read(buf)
+		if err != nil {
+			if err != io.EOF {
+				peer.Log.Errorf("failed to read message: %s", err)
+			}
+			return
+		}
+
+		msgType, err := messages.DetermineClientMsgType(buf[:n])
+		if err != nil {
+			log.Errorf("failed to determine message type: %s", err)
+			return
+		}
+		switch msgType {
+		case messages.MsgTypeBindNewChannel:
+			dstPeerId, err := messages.UnmarshalBindNewChannel(buf[:n])
+			if err != nil {
+				log.Errorf("failed to unmarshal bind new channel message: %s", err)
+				continue
+			}
+
+			channelID := r.store.Link(peer, dstPeerId)
+
+			msg := messages.MarshalBindResponseMsg(channelID, dstPeerId)
+			_, err = conn.Write(msg)
+			if err != nil {
+				peer.Log.Errorf("failed to response to bind request: %s", err)
+				continue
+			}
+			peer.Log.Debugf("bind new channel with '%s', channelID: %d", dstPeerId, channelID)
+		case messages.MsgTypeTransport:
+			msg := buf[:n]
+			channelId, err := messages.UnmarshalTransportID(msg)
+			if err != nil {
+				peer.Log.Errorf("failed to unmarshal transport message: %s", err)
+				continue
+			}
+
+			foreignChannelID, remoteConn, err := peer.ConnByChannelID(channelId)
+			if err != nil {
+				peer.Log.Errorf("failed to transport message from peer '%s' to '%d': %s", peer.ID(), channelId, err)
+				continue
+			}
+
+			err = transportTo(remoteConn, foreignChannelID, msg)
+			if err != nil {
+				peer.Log.Errorf("failed to transport message from peer '%s' to '%d': %s", peer.ID(), channelId, err)
+				continue
+			}
+		}
+	}
+}
+
+func transportTo(conn net.Conn, channelID uint16, msg []byte) error {
+	err := messages.UpdateTransportMsg(msg, channelID)
+	if err != nil {
+		return err
+	}
+	_, err = conn.Write(msg)
+	return err
+}
+
+func handShake(conn net.Conn) (*Peer, error) {
+	buf := make([]byte, 65535) // todo: reduce the buffer size
+	n, err := conn.Read(buf)
+	if err != nil {
+		log.Errorf("failed to read message: %s", err)
+		return nil, err
+	}
+	msgType, err := messages.DetermineClientMsgType(buf[:n])
+	if err != nil {
+		return nil, err
+	}
+	if msgType != messages.MsgTypeHello {
+		tErr := fmt.Errorf("invalid message type")
+		log.Errorf("failed to handshake: %s", tErr)
+		return nil, tErr
+	}
+	peerId, err := messages.UnmarshalHelloMsg(buf[:n])
+	if err != nil {
+		log.Errorf("failed to handshake: %s", err)
+		return nil, err
+	}
+	p := NewPeer(peerId, conn)
+	return p, nil
+}