Public bug reported: I found that linux kernel had had a bug in the implementation of IGMP membership report packet generation. the RFC documents for IGMP version 2 and 3 says that you must ignore the reports with a source ip address that you can't identify as belonging to a network assigned to the interface on which the packet was received. and the networking OS in the ToR switch, Force10 OS 9 does ignore it.
I've also figured out a patch has been made for this bug in Linus's Github. and there was a mark on Github that reads "v4.16-rc1". ( https://github.com/torvalds/linux/commit/a46182b00290839fa3fa159d54fd3237bd8669f0 ) I honestly have no idea how Ubuntu LTS team works with regard to this kind of patches from the fresh new upstream version of linux kernel. hope you guys will easily fix it for people like me who has no experience at building and distributing custom built kernels over a few servers. Test environment: I used two ToR switches and one linux machine for this test. I only used 2 ethernet ports on the linux machine. There was a recent version of Ubuntu with HWE kernel. I'm not sure if no-HWE one would be the same case - the version of linux-generic-hwe-16.04 was 4.13.0.32.52 - To test networking router stuff, I used the quagga from Cumulus Routing on the Host 3.3.2 ( https://cumulusnetworks.com/products/cumulus-routing-on-the-host/#roh-download-section ) What I did and saw in my case: 1. set a network interface (A) so it gets an IPv4 address, but also in vain issue "ip link set ${if_name} multicast off" 2. assign an IPv4 address to another network interface (B), but in this case with a 31-bit-long subnet mask length. 3. install quagga from cumulus, launch zebra and pimd, issue "ip pim sm" in the interface configuration mode for the interface (B) with a 31-bit-long subnet mask length 4. I checked that the source IP address part of the IGMP membership report packets from the linux machine is the address I assigned to the network interface (A) with 27-bit-long subnet mask -using dumpcap and tshark-, and that the PIM service on the switch ignored the Reports printing debugging messages including : "Invalid sender address" affects ubuntu Regards, Gunwoo -- You can find my PGP public key here: https://google.com/+DewrKim/about ** Affects: ubuntu Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1749058 Title: incorrect source address in IGMP Membership Report messages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1749058/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
