switch: invalid argument error while attempting to connect to client in active mode

[wmedlar]

Describe the bug Attempting to connect to a client in active mode will throw an "invalid argument" error, using v3.0.0 of ftpd on the Nintendo Switch.

To Reproduce Steps to reproduce the behavior:

1. spawn a netcat server to listen for incoming requests

   $ (nc -l 2560) &

2. attempt to list a directory in active mode

   $ nc "$SWITCH_IP" 5000 << EOF
   USER anonymous
   PORT $(ipconfig getifaddr en0 | tr . ,),10,0
   MLSD /
   EOF
   220 Hello!
   230 OK
   200 OK
   425 Can't open data connection

3. the UI will display (classic mode shows similar)

   [ERROR] connect: Invalid argument
   [RESPONSE] 425 Can't open data connection

Expected behavior The server connects to the client on the specified port and prints the directory listing.

Platform (please complete the following information):

• Client: MacOS Mojave
• System: Nintendo Switch
• System version: 10.1.0 | AMS 0.13.0 | S
• Launch method: fusee
• Classic? both

[mtheall]

Can you give more history from the log? Ideally starting with the received PORT command to the point of error.

[emannotava]

Sad that the op never replied because transfering files using passive mode is pretty annoying when you have a decently sized handful of files regardless of filesize.

[sasdallas]

Reopening this because it's happening to me. Here's the full log file.

[INFO] Started server at [XXX.XXX.X.XX]:5000
[INFO] Accepted connection from [XXX.XXX.X.XX]:59114
[RESPONSE] 220 Hello!
[COMMAND] USER ******
[RESPONSE] 230 OK
[COMMAND] SYST
[RESPONSE] 215 Unix Type: L8
[COMMAND] PORT XXX,XXX,X,XX,182,149
[RESPONSE] 200 OK
[COMMAND] LIST
[ERROR] connect: Invalid argument
[RESPONSE] 425 Can't open data connection
[COMMAND] PORT XXX,XXX,X,XX,133,83
[ERROR] connect: Invalid argument
[RESPONSE] 425 Can't open data connection