Mbed-os: Rebinding TCPServer socket more than once results in an infinite loop

[tommikas]

1. create and open a TCPServer socket
2. bind the socket to port X
3. bind the same socket again to port Y
4. bind any TCPServer type socket to port Z

Step 4 always results in an infinite loop in lwip_tcp.c : lines 425-426.

[0xc0170]

cc @geky

[tommikas]

http://jira.arm.com/browse/IOTSFW-2863

[sg-]

Please file these issues with a test case or example program or code snippet to reproduce.

[ciarmcom]

ARM Internal Ref: IOTMORF-443

[geky]

Looking into this more, it appears lwip does not handling rebinding sockets.

In BSD sockets, bind is similarly not allowed more than once:
http://man7.org/linux/man-pages/man2/bind.2.html

Fortunately, the state of the socket can be determined from the netconn struct, so changing the behaviour to return NSAPI_ERROR_PARAMETER is preferential to a non-halt state.

[geky]

Added a check per the above behaviour here: https://github.com/ARMmbed/mbed-os/pull/2580

Let us know if there is still an issue.

[tommikas]

changing the behaviour to return NSAPI_ERROR_PARAMETER is preferential to a non-halt state

Yep, that sounds good. I'll try it out.

[tommikas]

This has been fixed. Closing.