[client] Add experimental support for userspace routing (#3134)

client/cmd/trace.go

@@ -0,0 +1,137 @@
+package cmd
+
+import (
+	"fmt"
+	"math/rand"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"google.golang.org/grpc/status"
+
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+var traceCmd = &cobra.Command{
+	Use:   "trace <direction> <source-ip> <dest-ip>",
+	Short: "Trace a packet through the firewall",
+	Example: `
+  netbird debug trace in 192.168.1.10 10.10.0.2 -p tcp --sport 12345 --dport 443 --syn --ack
+  netbird debug trace out 10.10.0.1 8.8.8.8 -p udp  --dport 53
+  netbird debug trace in 10.10.0.2 10.10.0.1 -p icmp --type 8 --code 0
+  netbird debug trace in 100.64.1.1 self -p tcp --dport 80`,
+	Args: cobra.ExactArgs(3),
+	RunE: tracePacket,
+}
+
+func init() {
+	debugCmd.AddCommand(traceCmd)
+
+	traceCmd.Flags().StringP("protocol", "p", "tcp", "Protocol (tcp/udp/icmp)")
+	traceCmd.Flags().Uint16("sport", 0, "Source port")
+	traceCmd.Flags().Uint16("dport", 0, "Destination port")
+	traceCmd.Flags().Uint8("icmp-type", 0, "ICMP type")
+	traceCmd.Flags().Uint8("icmp-code", 0, "ICMP code")
+	traceCmd.Flags().Bool("syn", false, "TCP SYN flag")
+	traceCmd.Flags().Bool("ack", false, "TCP ACK flag")
+	traceCmd.Flags().Bool("fin", false, "TCP FIN flag")
+	traceCmd.Flags().Bool("rst", false, "TCP RST flag")
+	traceCmd.Flags().Bool("psh", false, "TCP PSH flag")
+	traceCmd.Flags().Bool("urg", false, "TCP URG flag")
+}
+
+func tracePacket(cmd *cobra.Command, args []string) error {
+	direction := strings.ToLower(args[0])
+	if direction != "in" && direction != "out" {
+		return fmt.Errorf("invalid direction: use 'in' or 'out'")
+	}
+
+	protocol := cmd.Flag("protocol").Value.String()
+	if protocol != "tcp" && protocol != "udp" && protocol != "icmp" {
+		return fmt.Errorf("invalid protocol: use tcp/udp/icmp")
+	}
+
+	sport, err := cmd.Flags().GetUint16("sport")
+	if err != nil {
+		return fmt.Errorf("invalid source port: %v", err)
+	}
+	dport, err := cmd.Flags().GetUint16("dport")
+	if err != nil {
+		return fmt.Errorf("invalid destination port: %v", err)
+	}
+
+	// For TCP/UDP, generate random ephemeral port (49152-65535) if not specified
+	if protocol != "icmp" {
+		if sport == 0 {
+			sport = uint16(rand.Intn(16383) + 49152)
+		}
+		if dport == 0 {
+			dport = uint16(rand.Intn(16383) + 49152)
+		}
+	}
+
+	var tcpFlags *proto.TCPFlags
+	if protocol == "tcp" {
+		syn, _ := cmd.Flags().GetBool("syn")
+		ack, _ := cmd.Flags().GetBool("ack")
+		fin, _ := cmd.Flags().GetBool("fin")
+		rst, _ := cmd.Flags().GetBool("rst")
+		psh, _ := cmd.Flags().GetBool("psh")
+		urg, _ := cmd.Flags().GetBool("urg")
+
+		tcpFlags = &proto.TCPFlags{
+			Syn: syn,
+			Ack: ack,
+			Fin: fin,
+			Rst: rst,
+			Psh: psh,
+			Urg: urg,
+		}
+	}
+
+	icmpType, _ := cmd.Flags().GetUint32("icmp-type")
+	icmpCode, _ := cmd.Flags().GetUint32("icmp-code")
+
+	conn, err := getClient(cmd)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	client := proto.NewDaemonServiceClient(conn)
+	resp, err := client.TracePacket(cmd.Context(), &proto.TracePacketRequest{
+		SourceIp:        args[1],
+		DestinationIp:   args[2],
+		Protocol:        protocol,
+		SourcePort:      uint32(sport),
+		DestinationPort: uint32(dport),
+		Direction:       direction,
+		TcpFlags:        tcpFlags,
+		IcmpType:        &icmpType,
+		IcmpCode:        &icmpCode,
+	})
+	if err != nil {
+		return fmt.Errorf("trace failed: %v", status.Convert(err).Message())
+	}
+
+	printTrace(cmd, args[1], args[2], protocol, sport, dport, resp)
+	return nil
+}
+
+func printTrace(cmd *cobra.Command, src, dst, proto string, sport, dport uint16, resp *proto.TracePacketResponse) {
+	cmd.Printf("Packet trace %s:%d -> %s:%d (%s)\n\n", src, sport, dst, dport, strings.ToUpper(proto))
+
+	for _, stage := range resp.Stages {
+		if stage.ForwardingDetails != nil {
+			cmd.Printf("%s: %s [%s]\n", stage.Name, stage.Message, *stage.ForwardingDetails)
+		} else {
+			cmd.Printf("%s: %s\n", stage.Name, stage.Message)
+		}
+	}
+
+	disposition := map[bool]string{
+		true:  "\033[32mALLOWED\033[0m", // Green
+		false: "\033[31mDENIED\033[0m",  // Red
+	}[resp.FinalDisposition]
+
+	cmd.Printf("\nFinal disposition: %s\n", disposition)
+}