From 07e23fe051f4e92acce40504eb92920a3e921838 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tam=C3=A1s=20Gul=C3=A1csi?= <T.Gulacsi@unosoft.hu>
Date: Wed, 17 Aug 2022 18:53:01 +0200
Subject: [PATCH] Use net.IP instead of netip.Addr

---
 ftp.go | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/ftp.go b/ftp.go
index 146a8fc..fb9e2bd 100644
--- a/ftp.go
+++ b/ftp.go
@@ -10,7 +10,6 @@ import (
 	"errors"
 	"io"
 	"net"
-	"net/netip"
 	"net/textproto"
 	"strconv"
 	"strings"
@@ -500,12 +499,9 @@ func (c *ServerConn) pasv() (host string, port int, err error) {
 	host = strings.Join(pasvData[0:4], ".")
 
 	if c.host != host {
-		if cmdIP, err := netip.ParseAddr(c.host); err == nil {
-			if dataIP, err := netip.ParseAddr(host); err == nil {
-				// Logic stolen from lftp (https://github.com/lavv17/lftp/blob/d67fc14d085849a6b0418bb3e912fea2e94c18d1/src/ftpclass.cc#L769)
-				if dataIP.IsMulticast() ||
-					cmdIP.IsPrivate() != dataIP.IsPrivate() ||
-					cmdIP.IsLoopback() != dataIP.IsLoopback() {
+		if cmdIP := net.ParseIP(c.host); cmdIP != nil {
+			if dataIP := net.ParseIP(host); dataIP != nil {
+				if isBogusDataIP(cmdIP, dataIP) {
 					return c.host, port, nil
 				}
 			}
@@ -514,6 +510,13 @@ func (c *ServerConn) pasv() (host string, port int, err error) {
 	return host, port, nil
 }
 
+func isBogusDataIP(cmdIP, dataIP net.IP) bool {
+	// Logic stolen from lftp (https://github.com/lavv17/lftp/blob/d67fc14d085849a6b0418bb3e912fea2e94c18d1/src/ftpclass.cc#L769)
+	return dataIP.IsMulticast() ||
+		cmdIP.IsPrivate() != dataIP.IsPrivate() ||
+		cmdIP.IsLoopback() != dataIP.IsLoopback()
+}
+
 // getDataConnPort returns a host, port for a new data connection
 // it uses the best available method to do so
 func (c *ServerConn) getDataConnPort() (string, int, error) {