[lime-dev] routing daemons fighting to enforce sysctl settings

Hi! I'm currently helping to switch from some ancient OLSR1-based hand-crafted and hard-to-maintain firmware to a Libre-Mesh based environment. In order to integrate with the existing OLSR1 mesh, some nodes should run BMX6/7 as well as OLSRd (using 2 devices is not an option, we just don't have enough of them). While this generally works nicely due to the routing-table-import features of BMX6, there is a single very annoying problem: Both routing daemons try changing sysctl settings in conflicting ways without any means for the user to disable that 'egocentric' behaviour. olsrd[21487]: Writing '0' (was 2) to /proc/sys/net/ipv4/conf/all/rp_filter bmx7[1237]: INFO check_proc_sys_net(): changing /proc/sys/net/ipv4/conf/all/rp_filter from 0 to 2 I generally believe that a routing daemon shouldn't take-over the OS to a degree which makes co-existence with other routing daemons or other networking stuff impossible. Currently both, OLSRd and BMX repeatingly try to enforce settings even in /proc/sys/net/ipv*/conf/all/ which thus affects all interfaces and not only the ones governed by that specific protocol. I had a discussion with Henning about a similar issue I had with OLSRd changing send_redirects without any way to configure it not to touch sysctl values. Now the problem came back and kinda confirms my opinion that setting sysctl options (/proc/sys/net/*) is a task to be carried out by the OS, ie. netifd on OpenWrt/LEDE or connman or NetworkManager or whatever-you-use. Thus my demand to routing protocols developers: Please at least create a way to tell your routing daemon "don't touch my sysctl, I'll take care of it myself!". This should imho be the default for the OpenWrt/LEDE build of the routing daemons and netifd should handle stuff like rp_filter and send_redirects -- the routing daemon might still warn you about UCI settings known to cause problems under certain conditions. Cheers Daniel