On 15/06/17 14:33, Nikolay Aleksandrov wrote: > On 15/06/17 00:51, Julien Gomes wrote: >> Hi Nikolay, >> >> On 06/14/2017 05:04 AM, Nikolay Aleksandrov wrote: >> >>> This has been on our todo list and I'm definitely interested in the >>> implementation. >>> A few things that need careful consideration from my POV. First are the >>> security >>> implications - this sends rtnl multicast messages but the rtnl socket has >>> the NL_CFG_F_NONROOT_RECV flag thus allowing any user on the system to >>> listen in. >>> This would allow them to see the full packets and all reports (granted they >>> can see >>> the notifications even now), but the full packet is like giving them the >>> opportunity >>> to tcpdump the PIM traffic. >> >> I definitely see how this can be an issue. >> From what I see, this means that either the packet should be >> transmitted another way, or another Netlink family should be used. >> >> NETLINK_ROUTE looks to be the logical family to choose though, >> but then I do not see a proper other way to handle this. > > Right, currently me neither, unless it provides a bind callback when > registering > the kernel socket. > >> >> However I may just not be looking into the right direction, >> maybe you currently have another approach in mind? > > I haven't gotten around to make (or even try) them but I was thinking about 2 > options > ending up with a similar result: > > 1) genetlink > It also has the NONROOT_RECV flag, but it also allows for a callback - > mcast_bind() > which can be used to filter. > > or > > 2) Providing a bind callback to the NETLINK_ROUTE socket. >
Ah nevermind, these cannot be used for filtering currently, so it seems the netlink interface would need to be extended too if going down this road. > I haven't checked in detail how feasible each option is. To me 2) seems like > the > cleaner/proper way to do it but it requires extending the rtnetlink api. > > It would be nice to get feedback and comments from more people on this. > >> >>> My second (more fixable and minor) concern is about the packet itself, how >>> do you >>> know that the packet is all linear so you can directly copy it ? >> >> Indeed, I overlooked this possibility in this version. >> I will improve that. >> > > Thanks! >
