in.c autoadding prefix route

[Max Laier]

On Fri, Nov 12, 2004 at 10:30:14AM +0200, Ruslan Ermilov wrote:
> Hi Max,
> 
> On Thu, Nov 11, 2004 at 09:24:05PM +0100, Max Laier wrote:
> > I know I have sent this a couple of times before, but never got anywhere. This 
> > time I am set to commit!
> > 
> Hey, you did it!  ;)
> 
> > The attached patch (http://people.freebsd.org/~mlaier/in.c.patch) derived from 
> > WIDE via OpenBSD in.c, rev 1.21 improves the handling of automatic prefix 
> > routes.
> > 
> > Right now you can't have two legs into the same network. If you want to, you 
> > must give on of the interfaces a host address only (netmask /32). This way it 
> > is not possible to hand over the route if one of the interfaces is 
> > "removed" (however this is done in the special case).
> > 
> > The patch allows to add more than on IPv4 address with the same prefix. In the 
> > case that there is a route already, we leave it alone and add the new address 
> > without the IFA_ROUTE flag. When we remove an address later on, that has a 
> > route associated, we try to find an alternative address to use for the route 
> > and hand it over.
> > 
> I cannot give your patch a thorough review at the moment, but I like the
> algorithm, and I don't see how it can hurt anything.
> 
> > --- ../dist/sys/netinet/in.c	Sat Nov  6 21:01:08 2004
> > +++ sys/netinet/in.c	Mon Nov  8 02:05:17 2004
> > @@ -654,14 +684,7 @@
> >  	register struct ifnet *ifp;
> >  	register struct in_ifaddr *ia;
> >  {
> > -
> > -	if ((ia->ia_flags & IFA_ROUTE) == 0)
> > -		return;
> > -	if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
> > -		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
> > -	else
> > -		rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
> > -	ia->ia_flags &= ~IFA_ROUTE;
> > +	in_scrubprefix(ia);
> >  }
> >  
> Looks like "ifp" argument is no longer needed for in_ifscrub(),
> perhaps it should be killed then.

As in_ifscrub() isn't static in in.c I think it must be considered kernel
API and hence I will wait with this cleanup 'till after the MFC. I otherwise
agree that it should be done.

> Also, there are a lot of style bugs (besides those that others
> have already mentioned), the most annoying is comments -- they
> should be written as per style(9) (make them look like the real
> sentences).

I updated the patch at: http://people.freebsd.org/~mlaier/in.c.patch with
new comments. Can you be more specific about the other style(9) violations,
as I don't seem to find them. K&R was choosen as the rest of in.c is K&R
still and I think style(9) requires that the overall style of a file is
maintained.

Thanks.

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