Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 20 May 2013 00:14:48 +0200 | Subject | Re: [PATCH 1/1] 6lowpan: Fix fragmentation with link-local compressed addresses | From | David Hauweele <> |
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Hello,
There is a patch which fixes link-local address uncompression:
http://permalink.gmane.org/gmane.linux.network.zigbee.devel/1717
I came across a similar solution but didn't submit it as another patch already existed. This patch instead focus on fragmented packet with link-local address compression, which is related but a different bug.
2013/5/19 Alexander Aring <alex.aring@gmail.com>: > Hi David, > > can you use a link-layer address on the current net-next kernel? > > I am asking because I can't use a link-layer address currently. > Your patch doesn't help to solve my problem with link-layer addresses. > > > To your patch: > > We get the link-layer addresses from skb not from the allocated > frame->skb. > > Here is the code: > > _saddr = mac_cb(skb)->sa.hwaddr; > _daddr = mac_cb(skb)->da.hwaddr; > > Here is skb != frame->skb so we don't need to copy it to frame->skb->cb > because we already the link-layer addresses from skb->cb. > > Is there another place in the code where we get the link-layer addresses > from allocated "frame" structure?
frame->skb is used to reassemble the 6lowpan packet when new fragments are received. This is the 'fragments assembling' switch at the beginning of lowpan_process_data(). It will reassemble fragments until the packet is successfully reassembled. Once it is, skb is replaced:
dev_kfree_skb(skb); skb = frame->skb; kfree(frame);
And the process continues as with other 6lowpan packets.
In particular:
_saddr = mac_cb(skb)->sa.hwaddr; _daddr = mac_cb(skb)->da.hwaddr;
Several lines later there are:
err = lowpan_uncompress_addr(skb, &hdr.saddr, lowpan_llprefix, lowpan_unc_llconf[tmp], skb->data); err = lowpan_uncompress_addr(skb, &hdr.daddr, lowpan_llprefix, lowpan_unc_llconf[tmp], skb->data);
These two lines should use _saddr/_daddr instead of skb->data, which fixes the link-local address uncompression. I'm able to use link-layer addresses with these two patches and it works well.
> > Regards > Alex
Regards,
David
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