routing message problem

[Li, Qing]

> 
> Dear all,
> 
> via a bug report from Preethi I figured out that there are no
> RTM_NEWADDR
> routing messages generated when an IP address is added to an interface
> and there is already an address in the same network configured.
> This is a problem for the SCTP stack.
> 
> To reproduce the problem you can
> sudo ifconfig em0 192.168.1.1
> sudo ifconfig em0 192.168.1.2 alias
> 
> and use the attached problem. It will only show the first address
> being added. This problem applies to FreeBSD 9.0 CURRENT and 7.2
> RELEASE.
> 
> Any idea how to fix the problem?
> 


  Please try my patch (not the final version) at 

	http://people.freebsd.org/~qingli/patch-8-28-rtmsg.diff


  I have tested it and seems to work as expected. You should
  get the notifications for both address insertion ("alias")
  and deletion ("-alias").

  Let me know if it's to your satisfaction.

  I found a couple of other issues while looking over the code.

  1. in_scrubprefix() is called unnecessarily in 2 locations
  2. the loopback host route is not removed for an alias

  On a related note, in.c can use some code cleanup. I think
  I will do that post 8.0 release.

  Thanks,

  -- Qing