ARP Changes

[Li, Qing]

>
> I know that arp has changed a lot in FreeBSD 8.  I am wondering if one
> change was by design?  In older versions of FreeBSD, if you ping a host
> that is on a local network but is down, after a few seconds ping displays:
>	ping: sendto: Host is down
>	ping: sendto: Host is down
>

  This turned out to be a regression bug. A wrong variable is used and
  the incomplete entry was timing out too fast. So the ARP probe continues
  indefinitely ...
  
>
> Using arp to display the arp table shows:
>
>	host.domain (x.x.x.x) at (incomplete) on em0 [ethernet]

  I wasn't returning incomplete entries, but now I am ...

  I have a patch for both issues, but I need to clean up the code
  because that wrong variable is used elsewhere in the same module.

  I should be able to commit a permanent fix by tomorrow.

  -- Qing