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Date:      Sun, 16 Jun 2002 15:51:31 -0700
From:      Terry Lambert <tlambert2@mindspring.com>
To:        Hajimu UMEMOTO <ume@mahoroba.org>
Cc:        arch@FreeBSD.org, hackers@FreeBSD.org
Subject:   Re: [CFR] max-child-per-ip restriction for inetd
Message-ID:  <3D0D1673.632F2386@mindspring.com>
References:  <ygey9dftiiw.wl@piano.mahoroba.org>

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Hajimu UMEMOTO wrote:
> I wish to add max-child-per-ip option to inetd.  This enables us to
> restrict maximum number of simultaneous invocations of each service
> from a single IP address.  The proposed patch can be found from:
> 
>     http://www.imasy.or.jp/~ume/FreeBSD/inetd-perip-5c.diff     (for 5-CURRENT)
>     http://www.imasy.or.jp/~ume/FreeBSD/inetd-perip-4s.diff     (for 4-STABLE)
> 
> If there is no objection, I'll commit it at next weekend.


Your search_ip() function is a linear list traversal, which
makes a lookup O(N).

Is there any change you could use a hash or a btree or a
skiplist or a trie or some other data structure *other*
than a linear list traversal?

It seems to me that this will make things incredibly slow
for everyone, if you have one IP address that's abusive
enough that it approaches the limit you set.

-- Terry

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