From 15d3ad82770ac1b2786563a1311d7e14a17a79db Mon Sep 17 00:00:00 2001
From: Sergey Berezansky <sergey@weka.io>
Date: Thu, 5 Sep 2024 09:50:26 +0300
Subject: [PATCH] refactor(CSI-249): identify source address for NFS target
 connection

---
 pkg/wekafs/apiclient/utils.go      | 36 ++++++++++++++++++++++++++++++
 pkg/wekafs/apiclient/utils_test.go | 20 +++++++++++++++++
 pkg/wekafs/nfsmount.go             | 21 +++++++++++------
 3 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/pkg/wekafs/apiclient/utils.go b/pkg/wekafs/apiclient/utils.go
index 56d43376b..9eede7da8 100644
--- a/pkg/wekafs/apiclient/utils.go
+++ b/pkg/wekafs/apiclient/utils.go
@@ -2,6 +2,7 @@ package apiclient
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"github.com/rs/zerolog/log"
 	"hash/fnv"
@@ -9,6 +10,7 @@ import (
 	"os"
 	"reflect"
 	"strings"
+	"time"
 )
 
 // ObjectsAreEqual returns true if both ApiObject have same immutable fields (other fields and nil fields are disregarded)
@@ -142,3 +144,37 @@ func GetNodeIpAddress() string {
 	}
 	return "127.0.0.1"
 }
+
+func GetNodeIpAddressByRouting(targetHost string) (string, error) {
+	rAddr, err := net.ResolveUDPAddr("udp", targetHost+":80")
+	if err != nil {
+		return "", err
+	}
+
+	// Create a UDP connection to the resolved IP address
+	conn, err := net.DialUDP("udp", nil, rAddr)
+	if err != nil {
+		return "", err
+	}
+	defer conn.Close()
+
+	// Set a deadline for the connection
+	err = conn.SetDeadline(time.Now().Add(1 * time.Second))
+	if err != nil {
+		return "", err
+	}
+
+	// Get the local address from the UDP connection
+	localAddr := conn.LocalAddr()
+	if localAddr == nil {
+		return "", errors.New("failed to get local address")
+	}
+
+	// Extract the IP address from the local address
+	localIP, _, err := net.SplitHostPort(localAddr.String())
+	if err != nil {
+		return "", err
+	}
+
+	return localIP, nil
+}
diff --git a/pkg/wekafs/apiclient/utils_test.go b/pkg/wekafs/apiclient/utils_test.go
index ede39534c..d15814dd9 100644
--- a/pkg/wekafs/apiclient/utils_test.go
+++ b/pkg/wekafs/apiclient/utils_test.go
@@ -1,6 +1,7 @@
 package apiclient
 
 import (
+	"github.com/rs/zerolog/log"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -27,3 +28,22 @@ func TestHashString(t *testing.T) {
 		})
 	}
 }
+
+func TestGetNodeIpAddressByRouting(t *testing.T) {
+	testCases := []struct {
+		targetHost string
+	}{
+		{"8.8.8.8"},
+		{"1.1.1.1"},
+		{"localhost"},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.targetHost, func(t *testing.T) {
+			ip, err := GetNodeIpAddressByRouting(tc.targetHost)
+			assert.NoError(t, err)
+			assert.NotEmpty(t, ip)
+			log.Info().Str("ip", ip).Msg("Node IP address")
+		})
+	}
+}
diff --git a/pkg/wekafs/nfsmount.go b/pkg/wekafs/nfsmount.go
index edb7c5e94..f14a35c62 100644
--- a/pkg/wekafs/nfsmount.go
+++ b/pkg/wekafs/nfsmount.go
@@ -131,23 +131,30 @@ func (m *nfsMount) doMount(ctx context.Context, apiClient *apiclient.ApiClient,
 			return errors.New("no API client for mount, cannot do NFS mount")
 		}
 
-		nodeIP := apiclient.GetNodeIpAddress()
-		if apiClient.EnsureNfsPermissions(ctx, nodeIP, m.fsName, m.clientGroupName) != nil {
-			logger.Error().Msg("Failed to ensure NFS permissions")
-			return errors.New("failed to ensure NFS permissions")
-		}
-
 		if err := m.ensureMountIpAddress(ctx, apiClient); err != nil {
 			logger.Error().Err(err).Msg("Failed to get mount IP address")
 			return err
 		}
 
+		nodeIP, err := apiclient.GetNodeIpAddressByRouting(m.mountIpAddress)
+		if err != nil {
+			logger.Error().Err(err).Msg("Failed to get routed node IP address, relying on node IP")
+			nodeIP = apiclient.GetNodeIpAddress()
+		}
+
+		if apiClient.EnsureNfsPermissions(ctx, nodeIP, m.fsName, m.clientGroupName) != nil {
+			logger.Error().Msg("Failed to ensure NFS permissions")
+			return errors.New("failed to ensure NFS permissions")
+		}
+
 		mountTarget := m.mountIpAddress + ":/" + m.fsName
 		logger.Trace().
 			Strs("mount_options", m.mountOptions.Strings()).
 			Str("mount_target", mountTarget).
+			Str("mount_ip_address", m.mountIpAddress).
 			Msg("Performing mount")
-		err := m.kMounter.MountSensitive(mountTarget, m.mountPoint, "nfs", mountOptions.Strings(), mountOptionsSensitive)
+
+		err = m.kMounter.MountSensitive(mountTarget, m.mountPoint, "nfs", mountOptions.Strings(), mountOptionsSensitive)
 		if err != nil {
 			if os.IsNotExist(err) {
 				logger.Error().Err(err).Msg("Mount target not found")