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Re: Possible fix for duplicated ARP entries in the FreeBSDstack
- From: Gary Thomas <gary at mlbassoc dot com>
- To: Sturle Mastberg <sturle dot mastberg at tandberg dot net>
- Cc: eCos Discussion <ecos-discuss at ecos dot sourceware dot org>
- Date: Fri, 17 Jun 2005 04:01:35 -0600
- Subject: Re: [ECOS] Possible fix for duplicated ARP entries in the FreeBSDstack
- References: <42B28F30.1070905@tandberg.net>
On Fri, 2005-06-17 at 10:52 +0200, Sturle Mastberg wrote:
> Hello,
>
> For some time I've had problem with duplicated ARP entries that have
> caused all sorts of problems. I searched the archive and discovered that
> the problem had been reported before:
>
>
> http://sourceware.org/ml/ecos-discuss/2004-11/msg00097.html
>
>
> My proposal to a fix is to make the sockaddr_inarp struct
> (include/netinet/if_ether.h) equal in size to the sockaddr struct by
> padding it at the end. This is exactly what is done to the sockaddr_in
> struct (include/netinet/in.h) for different reasons.
>
>
> I reached this conclusion after I discovered that two virutally
> identical calls to rtalloc1 (net/route.c) returned different results.
> The first instance appears in arplookup (netinet/if_ether.c) where the
> first parameter to rtalloc1 is a struct sockaddr_inarp cast to a struct
> sockaddr. The second instance appears in ip_output (netinet/ip_output)
> via rtalloc_ign (net/route.c) where the first parameter to rtalloc1 is
> an actual struct sockaddr. The rtalloc1 function does a radix tree
> search with a call to the rn_match function (net/radix.c). A closer look
> at this code reveals that it does indeed depend on the size of the
> supplied struct.
>
>
> The only conclusion a can draw from this is that the three structs:
> sockaddr, sockaddr_in and sockaddr_inarp must all be of equal size. I
> have checked the FreeBSD source repository that this is the case for the
> original code.
>
>
> While browsing the FreeBSD source repository I discovered that the
> sa_data character array member of the sockaddr struct was increased in
> size in the eCos FreeBSD stack. Does anyone know why this increase was
> introduced in eCos?
Can you provide the details of what you found? i.e. exactly how
these structures were modified during the port? [more likely, you're
looking at a newer version of the FreeBSD code than I used and the
changes happened in the BSD codebase] In any case, then we can analyze
how things are different and what might need to be done.
Thanks
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
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