Am 13.03.2015 um 14:53 schrieb Pablo Neira Ayuso: > On Fri, Mar 13, 2015 at 02:43:54PM +0100, Richard Weinberger wrote: >> Am 13.03.2015 um 13:15 schrieb Pablo Neira Ayuso: >>> On Fri, Mar 13, 2015 at 12:31:16PM +0100, Richard Weinberger wrote: >>>> The printed values are all of type unsigned integer, therefore use >>>> %u instead of %d. Otherwise an user can face negative values. >>>> >>>> Fixes: >>>> $ cat /proc/net/netfilter/nfnetlink_queue >>>> 0 29508 278 2 65531 0 2004213241 -2129885586 1 >>>> 1 -27747 0 2 65531 0 0 0 1 >>>> 2 -27748 0 2 65531 0 0 0 1 >>> >>> I guess you want to access stats on dropped packets. >> >> Correct. :) >> >>> I prefer if you extend nfnetlink_queue to provide statistics through >>> nfnetlink_queue, so you don't have to manually parse this text-based >>> /proc entry and we can deprecate this interface. That shouldn't have >>> been there in first place. >> >> You mean statistics via netlink attributes? I can add that! > > Add a new NFQNL_CFG_CMD_STATS command to request the statistics. If > NLM_F_DUMP is set, then we'll basically provide the full list of > instances. Otherwise, in case you want to retrieve stats for a > specific netlink socket, you can use the netlink portID as index. > And you'll have to add attributes for this new command, yes. This was my plan. Thanks for the pointer! >> But I think we should also fix the format string of the proc file >> as the fix is easy and non-intrusive. > > Unfortunately we don't know how many people are relying on that > output, I prefer to remain conservative and provide a proper netlink > interface for this. I understand your concerns but an application which is able to parse positive and negative numbers can also parse pure positives. Just made a small test application, glibc's %d in sscanf() can also deal with UINT_MAX. And I don't expect that applications to check whether the returned values from /proc/net/netfilter/nfnetlink_queue are between INT_MIN and INT_MAX. That said, I'd have assumed that an user would report negative values as plain kernel bug. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
