[patch] IPv6 fragments are assumed to be complete packets

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Currently TinyOS does not provide support for reassembling IPv6 fragments (only 
6lowpan fragments). Instead, it happily assumes that each fragment is a 
complete IPv6 packet. This is not a very wise thing to do. The attached patch 
addresses this problem by discarding such fragments before they're passed up 
the stack.

Original issue reported on code.google.com by jmatts...@dius.com.au on 10 Oct 2011 at 12:36

Attachments:

• tinyos-discard-fragments.patch

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Original comment by philip.l...@gmail.com on 14 Oct 2011 at 9:17

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Original comment by sdh...@gmail.com on 24 Oct 2011 at 3:31

• Changed state: Accepted

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I've committed and verified that this doesn't seem to break anything.  We do 
need to support IP fragmentation to be IPv6 compliant (IPv6 has a 1500 byte mtu 
that might require fragmentation) but there will be some code space overhead 
involved with doing this which I haven't been willing to do.  Maybe we make it 
an option.

Original comment by sdh...@gmail.com on 24 Oct 2011 at 9:57

• Changed state: Fixed

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Optional support for proper fragment handling would be great. The extra buffer 
space required for reassembly hurts though...

From memory there's also a shortcut taken over in the PPP code, where we only 
do 1280 instead of the RFC-mandated 1500.

Original comment by jmatts...@dius.com.au on 24 Oct 2011 at 10:05