buglwIP - A Lightweight TCP/IP stack - Bugs: bug #56964, lwIP2.1.2 assumes it connected to...


You are not allowed to post comments on this tracker with your current authentication level.

bug #56964: lwIP2.1.2 assumes it connected to remote server altough remote server sends "refuse" for the connection reques

Submitter:  Hunkar Ciplak <chunkar>
Submitted:  Sun 29 Sep 2019 10:38:44 AM UTC
Category:  TCP Severity:  3 - Normal
Item Group:  Feature Request Status:  Duplicate
Privacy:  Public Assigned to:  None
Open/Closed:  Closed Planned Release:  None
lwIP version:  2.1.1

Tue 08 Oct 2019 08:16:02 PM UTC, comment #3: 

Ok, please don't do that next time. And if you need to, say so. I'll close this one now.

Simon Goldschmidt <goldsimon>
Group administrator
Tue 08 Oct 2019 08:14:43 PM UTC, comment #2: 

Explanation is not clear, so i did submit new one because i couldn't update or delete this.

Hunkar Ciplak <chunkar>
Tue 08 Oct 2019 07:43:59 PM UTC, comment #1: 

What exactly is a "refuse packet"? Could you try to keep to standard wordings so everyone can understand what's meant?

Simon Goldschmidt <goldsimon>
Group administrator
Sun 29 Sep 2019 10:38:44 AM UTC, original submission:  

I came across an issue while trying to connect to remote TCP server by using non-blocking socket.
After sending the connection request by using lwip_connect, i am checking the errno and then i checking whether it writable or not by using the lwip_select. As known, when lwip_select returns "OK" then, it means client got connected to remote server successfully but lwip_connect and lwip_select does not return any error, although the connection request is refused by the remote TCP server.

Note: Just for example, on ubuntu you can send "refuse connection request" packet to clients when you follow the steps below:
1)nc -l 45678
2)CTRL+Z = stop netcad
3) After stopping netcad, when you send a connection request, ubuntu will send 'refuse' packet to your connection request. When you try to connect with your mobile phone, it will reported that it can not connect to remote server.
But when you try to connect with a non-blocking socket by using lwIP 2.1.2, then lwip_connect returns EINPROGRESS and lwip_select, returns 'socket is writable' / "OK" when the socket receives the 'refuse packet'.

Hunkar Ciplak <chunkar>


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

No files currently attached


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by goldsimon (Posted a comment)
  • -email is unavailable- added by chunkar (Submitted the item)

    There are 0 votes so far. Votes easily highlight which items people would like to see resolved in priority, independently of the priority of the item set by tracker managers.


    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-10-08 goldsimon StatusNone Duplicate
        Open/ClosedOpen Closed

    Back to the top

    Powered by Savane 3.13-b921.
    Corresponding source code