We've put considerable effort into cleaning up the checksum interface to make it as unambiguous as possible, please be very careful to follow it. Broken checksum processing is really hard to detect and debug. CHECKSUM_UNNECESSARY means that some number of _specific_ checksums (indicated by csum_level) have been verified to be correct in a packet. Blindly promoting CHECKSUM_NONE to CHECKSUM_UNNECESSARY is never right. If CHECKSUM_UNNECESSARY is set in such a manner but the checksum it would refer to has not been verified and is incorrect this is a major bug. Tom On Sat, Apr 30, 2016 at 12:40 PM, Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > > > On 04/30/2016 11:33 AM, Ben Hutchings wrote: >> >> On Thu, 2016-04-28 at 12:29 +0200, Sabrina Dubroca wrote: >>> >>> Hello, > > >>>> >>>> http://dmz2.candelatech.com/?p=linux-4.4.dev.y/.git;a=commitdiff;h=8153e983c0e5eba1aafe1fc296248ed2a553f1ac;hp=454b07405d694dad52e7f41af5816eed0190da8a >>> >>> Actually, no, this is not really a regression. >> >> [...] >> >> It really is. Even though the old behaviour was a bug (raw packets >> should not be changed), if there are real applications that depend on >> that then we have to keep those applications working somehow. > > > To be honest, I fail to see why the old behaviour is a bug when sending > raw packets from user-space. If raw packets should not be changed, then > we need some way to specify what the checksum setting is to begin with, > otherwise, user-space has not enough control. > > A socket option for new programs, and sysctl configurable defaults for raw > sockets > for old binary programs would be sufficient I think. > > > Thanks, > Ben > > -- > Ben Greear <greearb@xxxxxxxxxxxxxxx> > Candela Technologies Inc http://www.candelatech.com -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html