Fix docker build

client/internal/firewall.go

@@ -1,5 +1,3 @@
-//go:build !linux
-
 package internal
 
 import (
@@ -7,8 +5,15 @@ import (
 	"runtime"
 
 	"github.com/netbirdio/netbird/client/firewall"
+	"github.com/netbirdio/netbird/client/firewall/iptables"
 )
 
 func buildFirewallManager() (fw firewall.Manager, err error) {
-	return nil, fmt.Errorf("not implemented for this OS: %s", runtime.GOOS)
+	switch runtime.GOOS {
+	case "linux":
+		return iptables.Create()
+
+	default:
+		return nil, fmt.Errorf("not implemented for this OS: %s", runtime.GOOS)
+	}
 }

client/internal/firewall_linux.go

@@ -1,17 +0,0 @@
-package internal
-
-import (
-	"fmt"
-
-	"github.com/netbirdio/netbird/client/firewall"
-	"github.com/netbirdio/netbird/client/firewall/iptables"
-)
-
-func buildFirewallManager() (fw firewall.Manager, err error) {
-	fw, err = iptables.Create()
-	if err != nil {
-		// TODO: handle init nftables manager when it will be implemented
-		return nil, fmt.Errorf("create iptables manager: %w", err)
-	}
-	return fw, nil
-}