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microsoft / net-offloads

Specs for new networking hardware offloads.
MIT License
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QUIC Connection Address Affinity #39

Closed sourad closed 1 year ago

sourad commented 1 year ago

There are UdpPort and address fields, but only for destination. We probably need the 4-tuple to match against in absence of connection ID?

nibanks commented 1 year ago

You only need one address:port to do the match. If there is no CID, then everything matching that tuple matches the connection.

sourad commented 1 year ago

Can you please clarify the confusion I have below - Say there are 2 local IPs - Local_IP1 and Local_IP2 associated with an interface and 2 connections are established one from Local_IP1:Port_x and other from Local_IP2:Port_x to the same destination dest_IP:Port_y. Judging by the doc, I think the NDIS_QUIC_CONNECTION will contain dest_IP and Port_y in its address field and port field respectively. How would that disambiguate the 2 connections being offloaded here?

nibanks commented 1 year ago

I think the source of confusion is "destination" then. It's in the perspective of the packet. For a TX packet, that will be the remote tuple. For an RX packet, that will be the local tuple. Does that help?

sourad commented 1 year ago

I see. Yes, that does clear a part of my confusion. But I have one more:

Again, consider the scenario I outlined above: For Rx, that makes sense - we'll have 2 entries one per local tuple. For Tx we'll have 1 entry (since the remote tuple is same) which will be shared between the 2 connections? Is that okay? Is it guaranteed that the encryption parameters would be same for the 2 connections (even though they go to the same destination IP/port).

Similarly say the same local IP:Port is used to connect to 2 different destinations. Will we have just 1 entry (with local tuple) for the Rx offload for both connections?

nibanks commented 1 year ago

You can't practically have two QUIC connections without CID on the same port, because there's no way to demultiplex them. So, there shouldn't ever be a case where you'd want to add two null-CID connections to the same tuple.

nibanks commented 1 year ago

I've renamed this to narrow in on the question of "What part of the local address:port should be involved in QUIC packet routing?"

nibanks commented 1 year ago

Made it clear in the psuedocode I just merged. The local address and port are used.