On Wed, Nov 01, 2023 at 01:07:28PM -0500, Bob Pearson wrote: > Jason, > > I wrote a test program to verify that multicast is working in rxe > since there don't seem to be any pyverbs tests that actually test this. > It turns out that it doesn't work for several reasons most of which > I have fixed. But there is one that I can't figure out. > > The rxe driver calls dev_mc_add() with a MAC address to add the > multicast MAC address to the device which shows up when you type > 'ip maddr'. But nothing comes through from the network to the driver. > Wireshark does see the packets but they don't get to the IP or > UDP layers in the netdev stack. I think you also need to attach a multicast IP address to the RXE socket ? > So creating the IP mcast address seems critical to letting the > netdev stack receive traffic. Yes > I tried creating a separate UDP socket bound to the mcast address > but it doesn't seem to create the required IP address. I don't think that is how you do it... There is a set sock opt thing you need, IIRC. It has been a long time since I last wrote code for it Check what iperf did and that will be the basic thing that has to be cloned in the kernel Jason
