Re: switch dymmynet from mbuf based tagging to m_tag

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

:Hmm, that's problematic.  How about fixing it in following way:
:1) add a key field to ipfw rule (e.g. random number when rule was created)
:2) hash ipfw rules using above key, mainly to accelerate the following
:ipfw rule looking up
:3) when recording ipfw rule address in dummynet m_tag, the key of the
:ipfw rule is recorded in a seperate field in dummynet m_tag too
:4) in ipfw_chk(), we try finding the rule using the key recorded in
:dummynet m_tag, and compare the found ipfw rule address with the ipfw
:rule address recorded in dummynet m_tag, if they match then the rule
:is not deleted
:
:But I think that's a different problem than what the above patch
:intends to address, so I don't want to fix them in one patch :)
:
:Best Regards,
:sephe
:
:-- 
:Live Free or Die

    Yah, definitely a separate patch, don't let it interfere with your
    clean-up.

    In finding a solution we want to keep SMP in mind.  The more I look
    at it the more I worry about in-transit packets, especially when used
    with dynamic rules.

    I think putting the validation in ipfw_chk() is a good idea.  If I
    were doing it from scratch I would probably ref-count the rule structure
    and flag the deletion, but at this point in time a hash table would
    probably be less invasive.

    You don't need to generate a random key, just use the pointer address
    itself as the key.  I don't think we want to change the rule structure
    itself if we can help it, that will probably create userland
    incompatibilities.  I'll leave it up to you.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>