[lwip-devel] Re: [bug #27445] PCB hangs in Fast Retransmit due to unchanging cwnd

[address@hidden]

Bill Auerbach wrote:

> Follow-up Comment #8, bug #27445 (project lwip):
>
> Then you want:
>
> if ((u16_t)(pcb->cwnd + pcb->mss) < pcb->cwnd) { ... }
>
> If you add something to cwnd and it became less than the original cwnd, then
> it overflowed, right?
>   
The code wants to do something if it *doesn't* overflow:

/* Inflate the congestion window, but not if it means that
  the value overflows. */
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
 pcb->cwnd += pcb->mss;
}

> The initial point that I was trying to show is that the cast is meaningless
> and doesn't add anything.
>   
That's true, although that piece of code didn't get changed by what 
Kieran suggested - it's been in there for some time. Still, the cast can 
be removed, of course.

Simon