Sorry, I saw this discussion a little late... The Internet checksum is defined as a 1's-complement sum, so if the alternate 0 does not have a special meaning in a protocol, then by 1's-complement arithmetic, 0 == ~0. So, it looks to me without the remapping that a valid checksum may also fail, if it is simply computed in a different way (or on a different architecture) such that one gets 0 and one gets ~0 as un-modified answers. Since we're checking for equality on 2's-complement machines, I think the easiest thing is to still re-map it. Otherwise, instead of testing for 0, we have to test for both 0 and ~0 in the validity checks, right?
Disclaimer: I've just glanced through the discussion, so maybe I've misunderstood the point or effect of the patch... +-DLS - 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