Support get IPs for both guestagent and plain mode

Signed-off-by: Songpon Srisawai <[email protected]>

Author: songponssw

pkg/guestagent/api/client/client.go

@@ -76,3 +76,11 @@ func (c *GuestAgentClient) Tunnel(ctx context.Context) (api.GuestService_TunnelC
 	}
 	return stream, nil
 }
+
+func (c *GuestAgentClient) IPv4(ctx context.Context) (*api.CommandOutput, error) {
+	return c.cli.GetIPv4(ctx, &emptypb.Empty{})
+}
+
+func (c *GuestAgentClient) IPv6(ctx context.Context) (*api.CommandOutput, error) {
+	return c.cli.GetIPv6(ctx, &emptypb.Empty{})
+}

pkg/guestagent/api/guestservice.proto

@@ -11,6 +11,8 @@ service GuestService {
   rpc PostInotify(stream Inotify) returns (google.protobuf.Empty);
 
   rpc Tunnel(stream TunnelMessage) returns (stream TunnelMessage);
+  rpc GetIPv4(google.protobuf.Empty) returns (CommandOutput);
+  rpc GetIPv6(google.protobuf.Empty) returns (CommandOutput);
 }
 
 message Info {
@@ -30,6 +32,11 @@ message IPPort {
   int32 port = 3;
 }
 
+message CommandOutput {
+  bool is_json = 1;
+  bytes payload = 2;
+}
+
 message Inotify {
   string mount_path = 1;
   google.protobuf.Timestamp time = 2;

pkg/guestagent/api/server/server.go

@@ -56,3 +56,11 @@ func (s *GuestServer) PostInotify(server api.GuestService_PostInotifyServer) err
 func (s *GuestServer) Tunnel(stream api.GuestService_TunnelServer) error {
 	return s.TunnelS.Start(stream)
 }
+
+func (s *GuestServer) GetIPv4(ctx context.Context, _ *emptypb.Empty) (*api.CommandOutput, error) {
+	return s.Agent.IPv4(ctx)
+}
+
+func (s *GuestServer) GetIPv6(ctx context.Context, _ *emptypb.Empty) (*api.CommandOutput, error) {
+	return s.Agent.IPv6(ctx)
+}

pkg/guestagent/guestagent.go

@@ -14,4 +14,10 @@ type Agent interface {
 	Events(ctx context.Context, ch chan *api.Event)
 	LocalPorts(ctx context.Context) ([]*api.IPPort, error)
 	HandleInotify(event *api.Inotify)
+	IPv4(ctx context.Context) (*api.CommandOutput, error)
+	IPv6(ctx context.Context) (*api.CommandOutput, error)
+}
+
+type RouteEntry struct {
+	Dev string `json:"dev"`
 }

pkg/guestagent/guestagent_linux.go

@@ -5,8 +5,10 @@ package guestagent
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"os"
+	"os/exec"
 	"reflect"
 	"sync"
 	"syscall"
@@ -186,6 +188,7 @@ func (a *agent) collectEvent(ctx context.Context, st eventState) (*api.Event, ev
 	}
 	ev.AddedLocalPorts, ev.RemovedLocalPorts = comparePorts(st.ports, newSt.ports)
 	ev.Time = timestamppb.Now()
+
 	return ev, newSt
 }
 
@@ -368,3 +371,77 @@ func (a *agent) HandleInotify(event *api.Inotify) {
 		}
 	}
 }
+
+func (a *agent) IPv4(ctx context.Context) (*api.CommandOutput, error) {
+	return a.getIPAddress(ctx, "4")
+}
+
+func (a *agent) IPv6(ctx context.Context) (*api.CommandOutput, error) {
+	return a.getIPAddress(ctx, "6")
+}
+
+// getIPAddress performs two steps:
+// (1) Identifies the default interface using "ip route show default".
+// (2) Retrieves interface details for IPv4 or IPv6.
+// Returns nil if no default interface is found.
+func (a *agent) getIPAddress(_ context.Context, ipVersion string) (*api.CommandOutput, error) {
+	// Get default interface
+	iface, err := getDefaultInterface(ipVersion)
+	if err != nil {
+		logrus.Errorf("Error getting default interface: %v", err)
+	}
+
+	// Get Interface info
+	output, err := getInterfaceInfo(ipVersion, iface)
+	if err != nil {
+		logrus.Errorf("Error getting interface info for %s: %v", iface, err)
+	}
+
+	return &api.CommandOutput{
+		IsJson:  true,
+		Payload: output,
+	}, err
+}
+
+// getDefaultInterface fetches the default interface for IPv4 or IPv6.
+func getDefaultInterface(ipVersion string) (string, error) {
+	args := []string{"-j", "route", "show", "default"}
+	if ipVersion == "6" {
+		args = append([]string{"-6"}, args...)
+	} else {
+		args = append([]string{"-4"}, args...)
+	}
+
+	output, err := exec.Command("ip", args...).Output()
+	if err != nil {
+		return "", errors.New("failed to run `ip route show default`")
+	}
+
+	var routes []RouteEntry
+	if err := json.Unmarshal(output, &routes); err != nil {
+		return "", errors.New("failed to unmarshal route JSON")
+	}
+
+	// return nil if no default interface
+	if len(routes) == 0 || routes[0].Dev == "" {
+		return "", nil
+	}
+
+	return routes[0].Dev, nil
+}
+
+// getInterfaceInfo fetches the interface information for IPv4 or IPv6.
+func getInterfaceInfo(ipVersion, iface string) ([]byte, error) {
+	// No default route found
+	if iface == "" {
+		return nil, nil
+	}
+
+	args := []string{"-j", "address", "show", "dev", iface}
+	if ipVersion == "6" {
+		args = append([]string{"-6"}, args...)
+	} else {
+		args = append([]string{"-4"}, args...)
+	}
+	return exec.Command("ip", args...).Output()
+}

pkg/hostagent/api/api.go

@@ -4,5 +4,7 @@
 package api
 
 type Info struct {
-	SSHLocalPort int `json:"sshLocalPort,omitempty"`
+	SSHLocalPort     int    `json:"sshLocalPort,omitempty"`
+	GuestIPv4Address string `json:"guestIPv4Address,omitempty"`
+	GuestIPv6Address string `json:"guestIPv6Address,omitempty"`
 }