On Fri, 2006-07-14 at 12:12 -0400, Dan Reader wrote: > If we implement the approach you suggest and all data sent uses TSO, the > receiver can easily determine the expected codepoint of almost any > isolated CE packet. It simply has to look at the segment before and the > segment after (which it can wait for, thanks to delayed ACKs). If they > have the same ECT value, use that one. If they're different, then it > just has to perform a check for non-MSS (i.e. the boundary between TSOs > if send ops do not yield a multiple of MSS) and it might know.
I don't think it's that easy to guess. The TSO sizes are almost always multiples of MSS because they get trimmed or they are limited by the congestion window. The receiver will eventually make a mistake using your scheme above that the sender can reliably detect. I agree that replicating the ECT bits makes it less random, but it seems to be the simplest and best approach. In real life, there will be some TSO and some non-TSO packets making it even more difficult to guess. Randomizing the ECT bits in hardware makes verification of the nonce-sum very complicated and unreliable. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
