feat(forwarder): split forwarder to different file

core/tcp.go

@@ -0,0 +1,124 @@
+package core
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"net"
+
+	"tailscale.com/tsnet"
+)
+
+func runTCPForwarder(ctx context.Context, srv *tsnet.Server, rule ForwardRule, logger *slog.Logger) {
+	ip := getSelfTsnetAddr(srv)
+	ln, err := srv.Listen("tcp", fmt.Sprintf("%s:%d", ip.String(), rule.TailscalePort))
+	if err != nil {
+		logger.Error("failed to listen", "error", err)
+		return
+	}
+	logger.Debug("listening", slog.String("on", fmt.Sprintf("tailscale:%s:%d", ip.String(), rule.TailscalePort)))
+
+	go func() {
+		<-ctx.Done()
+		ln.Close()
+	}()
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			if ctx.Err() != nil {
+				return
+			}
+			logger.Error("accept error", "error", err)
+			continue
+		}
+		go handleTCPForward(ctx, srv, conn, rule, logger)
+	}
+}
+
+func handleTCPForward(ctx context.Context, srv *tsnet.Server, conn net.Conn, rule ForwardRule, logger *slog.Logger) {
+	remoteAddrStr := conn.RemoteAddr().String()
+	clog := logger.With(slog.String("remote", remoteAddrStr))
+
+	lc, err := srv.LocalClient()
+	if err == nil {
+		who, err := lc.WhoIs(ctx, remoteAddrStr)
+		if err == nil {
+			clog = clog.With(slog.String("user", who.UserProfile.LoginName))
+		}
+	}
+
+	connType := getConnType(ctx, srv, remoteAddrStr)
+	clog.Info("accepted connection",
+		slog.String("conn_type", connType),
+		slog.String("local_addr", rule.LocalAddr),
+	)
+
+	localConn, err := dialTCP(ctx, rule.LocalAddr)
+	if err != nil {
+		clog.Error("failed to dial local", "error", err)
+		conn.Close()
+		return
+	}
+
+	stop := context.AfterFunc(ctx, func() {
+		conn.Close()
+		localConn.Close()
+	})
+	defer stop()
+
+	toLocal, toTs := pipeConns(conn, localConn)
+	clog.Info("connection closed", slog.Int64("ts_rx_bytes", toLocal), slog.Int64("ts_tx_bytes", toTs))
+}
+
+func runTCPConnector(ctx context.Context, srv *tsnet.Server, rule ConnectRule, logger *slog.Logger) {
+	bindIP := rule.BindIP()
+	if rule.LANEnabled() && rule.LocalAddr != "" && rule.LocalAddr != "0.0.0.0" {
+		logger.Warn("lan_enable forces local_addr to 0.0.0.0, overriding")
+	}
+	addr := fmt.Sprintf("%s:%d", bindIP, rule.LocalPort)
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		logger.Error("failed to listen locally", "error", err)
+		return
+	}
+	logger.Info("listening", slog.String("on", addr))
+
+	go func() {
+		<-ctx.Done()
+		ln.Close()
+	}()
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			if ctx.Err() != nil {
+				return
+			}
+			logger.Error("accept error", "error", err)
+			continue
+		}
+		go handleTCPConnect(ctx, srv, conn, rule, logger)
+	}
+}
+
+func handleTCPConnect(ctx context.Context, srv *tsnet.Server, conn net.Conn, rule ConnectRule, logger *slog.Logger) {
+	clog := logger.With(slog.String("local_client", conn.RemoteAddr().String()))
+
+	tsConn, err := dialTsnet(ctx, srv, "tcp", rule.DstAddr)
+	if err != nil {
+		clog.Error("failed to dial tailscale", "error", err)
+		conn.Close()
+		return
+	}
+
+	stop := context.AfterFunc(ctx, func() {
+		conn.Close()
+		tsConn.Close()
+	})
+	defer stop()
+
+	clog.Info("accepted connection", slog.String("dst_addr", rule.DstAddr))
+	toConn, toTs := pipeConns(conn, tsConn)
+	clog.Info("connection closed", slog.Int64("ts_rx_bytes", toTs), slog.Int64("ts_tx_bytes", toConn))
+}