how does linux kernel process out-of-order tcp segment?

Question

I'm devleoping a multi rx threads ethernet driver, but this may lead to potential issuse that delivery out-of-order packets to linux network stack. this issue has been verified on PPTP connection, because GRE has sequence number and will drop out-of-order packets. So, does TCP has an tcp reassembly queue or similar mechanism to process out-of-order segment.

Answer 1

TCP has a window buffer. As packets arrive they are cached until the next expected packet sequence number is received. When the next expected packet is received (and it's valid), it's passed onto the application for receiving in order.

see https://www.quora.com/How-does-TCP-handle-the-duplicate-segments-and-out-of-order-segments