[lwip-devel] [patch #9472] tcp_kill_prio: Don't kill active connection that has the same priority

[Axel Lin]

URL:
  <http://savannah.nongnu.org/patch/?9472>

                 Summary: tcp_kill_prio: Don't kill active connection that has
the same priority
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: axellin
            Submitted on: Thu 26 Oct 2017 02:01:16 PM UTC
                Category: None
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

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Details:

When running out of pcb, the tcp_alloc call the tcp_kill_prio and it kills
active connection that has the same priority.
Using netconn APIs will always create tcp pcb with TCP_PRIO_NORMAL, thus
create new connection will always kill existing active connections rather than
fail to create new connection. This behavior looks wrong.

This patch avoid killing active connection that has the same priority, only
kills active connection with lower priority.


Note, cannot just changing "pcb->prio <= mprio" to "pcb->prio < mprio" because
with that change we do not kill the oldest active connection.
Thus I add checking mprio < prio to avoid kill the same priority pcb.




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File Attachments:


-------------------------------------------------------
Date: Thu 26 Oct 2017 02:01:16 PM UTC  Name:
0001-tcp_kill_prio-Don-t-kill-active-connection-that-has-.patch  Size: 3KiB  
By: axellin

<http://savannah.nongnu.org/patch/download.php?file_id=42269>

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