Adds a public IP flag for ftp. Closes #3158

Fixed variable names

cmd/serve/ftp/ftp.go

@@ -78,6 +78,7 @@ func newServer(f fs.Fs, opt *ftpopt.Options) (*server, error) {
 		},
 		Hostname:     host,
 		Port:         portNum,
+		PublicIp:     opt.PublicIP,
 		PassivePorts: opt.PassivePorts,
 		Auth: &Auth{
 			BasicUser: opt.BasicUser,

cmd/serve/ftp/ftpflags/ftpflags.go

@@ -16,6 +16,7 @@ var (
 func AddFlagsPrefix(flagSet *pflag.FlagSet, prefix string, Opt *ftpopt.Options) {
 	rc.AddOption("ftp", &Opt)
 	flags.StringVarP(flagSet, &Opt.ListenAddr, prefix+"addr", "", Opt.ListenAddr, "IPaddress:Port or :Port to bind server to.")
+	flags.StringVarP(flagSet, &Opt.PublicIP, prefix+"public-ip", "", Opt.PublicIP, "Public IP address to advertise for passive connections.")
 	flags.StringVarP(flagSet, &Opt.PassivePorts, prefix+"passive-port", "", Opt.PassivePorts, "Passive port range to use.")
 	flags.StringVarP(flagSet, &Opt.BasicUser, prefix+"user", "", Opt.BasicUser, "User name for authentication.")
 	flags.StringVarP(flagSet, &Opt.BasicPass, prefix+"pass", "", Opt.BasicPass, "Password for authentication. (empty value allow every password)")

cmd/serve/ftp/ftpopt/ftp_options.go

@@ -24,6 +24,7 @@ You can set a single username and password with the --user and --pass flags.
 type Options struct {
 	//TODO add more options
 	ListenAddr   string // Port to listen on
+	PublicIP     string // Passive ports range
 	PassivePorts string // Passive ports range
 	BasicUser    string // single username for basic auth if not using Htpasswd
 	BasicPass    string // password for BasicUser
@@ -32,6 +33,7 @@ type Options struct {
 // DefaultOpt is the default values used for Options
 var DefaultOpt = Options{
 	ListenAddr:   "localhost:2121",
+	PublicIP:     "",
 	PassivePorts: "30000-32000",
 	BasicUser:    "anonymous",
 	BasicPass:    "",