On 31/05/11 11:51, Maciej Åenczykowski wrote: >>>> -A OUTPUT -p 6 --dport 888 -o eth1 -j IPMARK --addr >>>> dst --and-mask -1 --or-mask -64 --shift 0 >>>> After upgrading to iptables 1.4.11 the following iptables-restore error is >>>> produced: >>>> >>>> iptables-restore v1.4.11: IPMARK: Bad value for "and-mask" option: "-1" >>> >>> This is intentional. Bitwise operations work best when fed unsigned numbers >>> only. >> >> but this used to work, we shouldn't break this sort of things Jan. > > Assuming 2's complement arithmetic, an --and-mask of -1 should be a no-op > (since -1 is all 1's in binary) > > However when reading --and-mask -1 my first gut instinct is that this > is --and-mask ~1 and is thus clears the least significant bit. > I also instinctively incorrectly assume --or-mask -64 sets all but bit > 6, when it is actually setting all but the bottom 6 bits (ie. bits 0 > through 5)... > > To me this sort of lack of clarity is undesirable, and I can certainly > understand the desire to disable masks with negative integers. makes sense, thanks for the clarification. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
