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Message-ID: <87iqmu36i1.fsf@basil.nowhere.org> Date: Sat, 28 Feb 2009 16:50:46 +0100 From: Andi Kleen <andi@...stfloor.org> To: Oliver Zheng <mailinglists+netdev@...verzheng.com> Cc: netdev@...r.kernel.org Subject: Re: TCP/IP stack interpretation of acceptable packet Oliver Zheng <mailinglists+netdev@...verzheng.com> writes: > I was investigating behaviour of the TCP/IP stacks and noticed that > Linux has a peculiarity. When a packet is received with the correct > sequence number but incorrect acknowledgement number (in my tests, it > was higher than the correct acknowledgement number), the stack accepts > the packet as a valid packet and passes the data up to the application > (I do not know whether the ack information is accepted). According to > the list of tests described here in the TCP RFC 793 [1], accepting a > packet requires the packet to satisfy both sequence and > acknowledgement number tests; otherwise, the entirety of the packet > (its data and its acknowledgement information confirming reception of > previous data) should be dropped. Is this intentional, a bug, or am I > misinterpreting something? A nice flow chart that explains this > procedure is here [2]. Sounds like a bug to me, when the ack is outside the window. -Andi -- ak@...ux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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