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You can't include the source port in the hash, because this is a table of listening sockets, i.e. no connection has been established yet and the socket needs to see packets from ANY source as long as they go to the right destination.

You could suggest including the bound destination IP in the hash, but then you'd also need a separate hashtable for sockets that are bound to any IP (instead of being bound to a specific IP).

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Good catch. I did mean that mixing in the source would apply to the established table if it's constructed in the same way but doesn't do so already (which would surprise me now that I think about it properly).

I don't think that you'd need a separate table for star bound listeners if the IP is mixed in since you could just hash in 0.0.0.0 but you'd need to check both the real IP and the special value too which is a potentially damaging performance hit. It's probably done with just the destination port for a good reason.

You wouldn't need a separate hash table, you could first look up Hash(destip, destport) then if that fails to find a listener, look up Hash(0, destport).

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