Use hostname for FTPS EPSV data connection

This allows FTPS to reuse the TLS session
of the FSTP command connection for the data connection.

Author: codingtim

src/main/java/org/apache/commons/net/ftp/FTPClient.java

@@ -828,10 +828,14 @@ protected void _parseExtendedPassiveModeReply(String reply) throws MalformedServ
             throw new MalformedServerReplyException("Could not parse extended passive host information.\nServer Reply: " + reply);
         }
         // in EPSV mode, the passive host address is implicit
-        passiveHost = getRemoteAddress().getHostAddress();
+        passiveHost = _resolveExtendedPassiveModeHost();
         passivePort = port;
     }
 
+    protected String _resolveExtendedPassiveModeHost() {
+        return getRemoteAddress().getHostAddress();
+    }
+
     /**
      * Parses a reply.
      *

src/main/java/org/apache/commons/net/ftp/FTPSClient.java

@@ -1119,5 +1119,14 @@ protected void sslNegotiation() throws IOException {
             throw new SSLHandshakeException("Hostname doesn't match certificate");
         }
     }
+
+    @Override
+    protected String _resolveExtendedPassiveModeHost() {
+        if (_socket_ instanceof SSLSocket) {
+            return ((SSLSocket) _socket_).getSession().getPeerHost();
+        } else {
+            return super._resolveExtendedPassiveModeHost();
+        }
+    }
 }