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SubjectRe: [Masq-dev] Use daddr and dport as hash keys for faster masq redirector!
On Sat, 12 Jun 1999, Julian Anastasov wrote:

> The worse case will be if a masq module creates large number of rev
> or normal masq entries with NO_DADDR and/or NO_DPORT flags to same
> maddr and mport or to same saddr and sport and no connection take
> place (flood from outside the firewall to create such inactive
> entries).

And this case isn't too bad either - it's no worse than the current
situation of not having a destination list.

> - we must use d{addr,port} as the only hash keys for
> m_tab only when F_MPORT=1. So, better to use
> d{addr,port}+m{addr,port} as keys for m_tab.

I disagree, still. The d{addr,port} lookup in __ip_masq_in_get()
should find it quickly without having "special case" keying; this
strikes me as an unnecessary complication.

> - using prev link for each table is a way to speedup
> unhash/rehash for entries with value 0 in d{addr,port}
> or s{addr,port},

Why would it hurt other entries? I think it's a win regardless.

I think you're trying to trade clarity and flexibility for memory
footprint. I'd rather see the following lists:

s{addr,port}
d{addr,port}
m{addr,port}
s+d{addr,port}
m+d{addr,port}

...and no "special case" keying. For NO_D* | F_DLOOSE ip_masq_hash()
could simply *not hash* the entry into the destination lists. This
means 10 pointers per ms (each being a doubly-linked list), and two or
five hash operations in ip_masq_hash() depending on the flags. Is this
too expensive?

--
John Hardin KA7OHZ jhardin@wolfenet.com
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