RE: [lwip-users] Dropping existing TCP connections to service new ones

[Bill Auerbach]

> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On Behalf
> Of Art R.
> Sent: Wednesday, February 20, 2008 2:04 PM
> To: address@hidden
> Subject: [lwip-users] Dropping existing TCP connections to service new
> ones
> 
> 
> The tcp.c module has function tcp_kill_prio which is used to kill existing
> TCP connections when a new connection is being attempted and there is an
> 'out of PCBs' situation. The comment in that function says "kill the
> oldest
> active connection that has lower priority than prio", but the test it
> performs is "...pcb->prio <= prio". This appears to allow a new connection
> to kill an existing one of the same priority.
> 
> The default case is that all pcbs will have the same priority ("normal"),
> so
> the oldest is killed.
> 
> Is this a bug? Should the code read "if (pcb->prio < prio && ..."  (less
> than instead of less or equal)?
> Or is it intentional?
> 
> What would be the best way to disable the killing of active connections?
> (Preferably without modifying the lwIP source code.)

Can't you call tcp_setprio with a value of TCP_PRIO_MAX+1 for each pcb?

Bill