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Date:      Fri, 07 Dec 2012 16:27:06 +0400
From:      "Andrey V. Elsukov" <>
To:, freebsd-ipfw <>
Subject:   [RFC] IPv6 ifaddr hash
Message-ID:  <>

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Hi All,

We have discovered that ipfw(4) shows very low performance results with
our rules. One of the biggest problems is rules with O_IP6_XXX_ME
opcode. They checks match or not match packet's addresses with locally
configured IPv6 addresses.

For IPv4 we have an in_ifaddr hash for the quick search an address, but
not for the IPv6. So, I have implemented the first patch based on the
code for the IPv4, but there are several questions I want to discuss.

The patch is here:

1. The hash size. I made it the same what IPv4 has. But I think 512
buckets is too many.

2. What hash function is better to use?

3. Using the whole 128 bit of address to hash seems like overkill.

WBR, Andrey V. Elsukov

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