Date: Fri, 23 Nov 2001 18:08:45 -0800 (PST) From: Paul Herman <pherman@frenchfries.net> To: Ruslan Ermilov <ru@FreeBSD.ORG> Cc: <freebsd-net@FreeBSD.ORG> Subject: Re: arp_rtrequest: bad gateway value Message-ID: <20011123160634.I49441-100000@tick.sc.omation.com> In-Reply-To: <20011122113610.C32952@sunbay.com>
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On Thu, 22 Nov 2001, Ruslan Ermilov wrote:
> On Wed, Nov 21, 2001 at 05:32:27PM -0800, Paul Herman wrote:
> > Hi,
> >
> > I'd like to pick some brains before I file a PR.
> >
> There's already a PR open on this, kern/29170.
>
> [...]
>
> There's the problem with routed(8). It issues a command
> similar to "route change ip ip" for each (but last) IP address
> of an interface if the route already exists and is different.
> This results in a changed route with AF_INET gateway, but
> route's IFA still points to Ethernet device and
> rt_ifa->ifa_rtrequest == arp_rtrequest. This results in this
> message as AF_INET != AF_LINK. The message is harmless.
Well this definately seems to me like bug in the kernel, because
route_output()/arp_rtrequest() both allow me to change the gateway
from a link addr to an inet addr, but still retain the RTF_LLINFO
flag. This is an inconsistent state and should not be allowed.
Correct me if I'm wrong, but is there any (historical) case where
you would want this state?
Possible solutions:
1) Ignore the change of the gateway if the AF_ type and
RTF_ flags don't jive.
2) Return an EINVAL if you try to assign an AF_INET gateway
to an existing route that has RTF_LLINFO set.
3) If an AF_INET gateway is given to an existing route with
RTF_LLINFO set, try to convert the address to its link layer
address, and then update the route.
IMO, although #1 obeys POLA but might be to permissive, and #3 is
probably to complicated for the kernel to do, so I think #2 might
be best.
Solution #2 would break routed, of course, so it would also have to
be changed, as well. FWIW gated works fine and doesn't exhibit the
same behaviour that routed does. Dunno about zebra, haven't
checked.
I'll be happy to see if I can whip up a patch, what does everyone
else think?
-Paul.
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