[Click] Click-align questions

[springbo@cs.wisc.edu]

Hello,

I've run into some issues with click-align. Anything to get me going along
the correct path would be greatly appreciated.

Click-align adds the align elements needed, but does not seem to add the
elements needed to transform the packets back to the alignment needed to
pass the packet to the host [ToHost()]. So if I pass a packet to the host
downstream of a CheckIPHeader in an click-aligned configuration
('click-align test1.click'), then a dump from the host results in
unaligned data. But if I manually change back to the correct alignment the
traffic is correctly captured ('click-align test2.click').

>From there I decided to manually enter the correct alignments before
passing data to the host, but the manual aligns seem to cause issues with
click-align. Running click-align on test3.click generated an invalid
configuration. The last line of the configuration has an align element
with no input. Are manual aligns with click-align not a good idea?

Is there way to automatically reset alignment before passing ToHost, or
better yet is there a way to get click-align to transform the alignment
back? Or am I missing something?

These results were seen on both a 686 FC6 2.6.19.2 virtual machine and a
x86_64 CentOs5 2.6.19.2 box. I downloaded and built the most recent dev
tree this morning (click-align --version => click-align (Click) 1.6.0).

Also, it does not seem that click-align catches mis-alignments do to
arguments passed to CheckIPHeader. Such that CheckIPHeader(14) still
results in "warning: IP header unaligned, cannot use fast IP checksum"
even after being passed through click-align. From the documentation of
click-align I cannot tell if this is intended or not.

Thanks for any help,
Kevin Springborn
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