Bug: ftpserver does not start with active mobile hotspot/tethering

[primesun]

Issue
When my phone has an active hotspot, and another device (such as a laptop) is connected to that hotspot, the FTP server doesn't work.

Expected behaviour
When I start the FTP server it correctly detects that my phone is running a hotspot, obtains its IP address in the hotspot network, and starts the FTP server successfully.

Actual behaviour
When I start the FTP server it says in the app "Failed to start the FTP server, unable to get IP address". And in the app's notification, it says "FTP Server is running at -".

App & Device Information
App version 3.1 - 30100 (16-36)
Pixel 6a
Android 16

Related Issues

• ftpserver does not start with active mobile hotspot/tethering #14 Seems to be the same issue from 2013, and it says it was fixed
• No IP address when in hotspot #134
• [FEATURE] Show Hotspot IP in addition to WIFI IP #262
• Option to autoconnect FTP Server whenever WiFi Hotspot is turned on #94 Not exactly sure if this is related or not, seems more about autoconnect.

[Xavron]

Due to complexity, some more clarifications have been made.

Third time is it :)

Found actual cause:

• Where Switftp is on hotspot server device. Samsung ROM (hotspot server w/o wifi) with Swiftp there causes "Failed to start the FTP server, unable to get IP address".

• In other words: for mobile data or no wifi/USB LAN (when ROM blocks this), IP isn't assigned here as is.

  • The previous issues were not really reflecting on the issue here. This issue does not make it clear enough as Swiftp can get assigned IP and does work with hotspot.

• Oppositely, Swiftp on the hotspot client device already works.

• When Swiftp is on hotspot server device:

  • This already works when ROM allows both wifi and hotspot to both be in use. I tested this as working. Not all ROMs allow this.

  • When hotspot force disables wifi (aka networking), Swiftp does not receive IP and fails to start.

  • To connect here, must either go into wifi on hotspot client device and obtain the ASSIGNED BY HOTSPOT SERVER gateway IP (I tested this as working) or possibly set up and connect remotely via internet (I'm not testing remote here).

  • Remote connectable IP via data may not be a good idea here as there's no router wall or similar.

#277

• To note, I'm not testing the pull request, but...

• Swiftp on hotspot server device where ROM also allows wifi at same time already works here w/o any changes. In other words, w/o the pull request. (And Swiftp on hotspot client does too).

• For Swiftp on hotspot server: The hotspot will assign its own HOTSPOT SERVER PROVIDED IP AND GATEWAY to hotspot client device. The IP in Swiftp shown could be incorrect for use even though connection can still happen when FTP client is set to connect using hotspot server gateway IP.

• This should get into deciding how to assign what IP and when as server vs client will be different IP among other variations possibly. Perhaps this could be determined by code but am not sure. That could be tricky as can't assign gateway when on client and may or may not be correct to assign network IP when on server but should be able to assign gateway. Might be easier to have a manual IP selection or edit. Idk. Hurts my brain :)

As this is the actual cause, I'm not testing or looking into it any further.