Submitted SRU request for Bionic, Cosmic. Huge thanks for the testing, Matthew!
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1794232 Title: Geneve tunnels don't work when ipv6 is disabled Status in linux package in Ubuntu: Fix Released Status in linux source package in Xenial: In Progress Status in linux source package in Bionic: In Progress Status in linux source package in Cosmic: In Progress Status in linux source package in Disco: Fix Released Bug description: SRU Justification Impact: Cannot create geneve tunnels if ipv6 is disabled dynamically. Fix: Fixed by upstream commit in v5.0: Commit: cf1c9ccba7308e48a68fa77f476287d9d614e4c7 "geneve: correctly handle ipv6.disable module parameter" Hence available in Disco and later; required in X,B,C. Testcase: 1. Boot with "ipv6.disable=1" 2. Then try and create a geneve tunnel using: # ovs-vsctl add-br br1 # ovs-vsctl add-port br1 geneve1 -- set interface geneve1 type=geneve options:remote_ip=192.168.x.z // ip of the other host Regression Potential: Low, only geneve tunnels when ipv6 dynamically disabled, current status is it doesn't work at all. Other Info: * Mainline commit msg includes reference to a fix for non-metadata tunnels (infrastructure is not yet in our tree prior to Disco), hence not being included at this time under this case. At this time, all geneve tunnels created as above are metadata-enabled. --- [Impact] When attempting to create a geneve tunnel on Ubuntu 16.04 Xenial, in an OS environment with open vswitch, where ipv6 has been disabled, the create fails with the error : “ovs-vsctl: Error detected while setting up 'geneve0': could not add network device geneve0 to ofproto (Address family not supported by protocol)." [Fix] There is an upstream commit for this in v5.0 mainline (and in Disco and later Ubuntu kernels). "geneve: correctly handle ipv6.disable module parameter" Commit: cf1c9ccba7308e48a68fa77f476287d9d614e4c7 This fix is needed on all our series prior to Disco and the v5.0 kernel: X, C, B. It is identical to the fix we implemented and tested internally with, but had not pushed upstream yet. [Test Case] (Best to do this on a kvm guest VM so as not to interfere with your system's networking) 1. On any Ubuntu Xenial kernel, disable ipv6. This example is shown with the 4.15.0-23-generic kernel (which differs slightly from 4.4.x in symptoms): - Edit /etc/default/grub to add the line: GRUB_CMDLINE_LINUX="ipv6.disable=1" - # update-grub - Reboot 2. Install OVS # apt install openvswitch-switch 3. Create a Geneve tunnel # ovs-vsctl add-br br1 # ovs-vsctl add-port br1 geneve1 -- set interface geneve1 type=geneve options:remote_ip=192.168.x.z (where remote_ip is the IP of the other host) You will see the following error message: "ovs-vsctl: Error detected while setting up 'geneve1'. See ovs-vswitchd log for details." From /var/log/openvswitch/ovs-vswitchd.log you will see: "2018-07-02T16:48:13.295Z|00026|dpif|WARN|system@ovs-system: failed to add geneve1 as port: Address family not supported by protocol" You will notice from the "ifconfig" output that the device genev_sys_6081 is not created. If you do not disable IPv6 (remove ipv6.disable=1 from /etc/default/grub + update-grub + reboot), the same 'ovs-vsctl add-port' command completes successfully. You can see that it is working properly by adding an IP to the br1 and pinging each host. On kernel 4.4 (4.4.0-128-generic), the error message doesn't happen using the 'ovs-vsctl add-port' command, no warning is shown in ovs-vswitchd.log, but the device genev_sys_6081 is also not created and ping test won't work. With the fixed test kernel, the interfaces and tunnel is created successfully. [Regression Potential] * Low -- affects the geneve driver only, and when ipv6 is disabled, and since it doesn't work in that case at all, this fix gets the tunnel up and running for the common case. [Other Info] * Analysis Geneve tunnels should work with either IPv4 or IPv6 environments as a design and support principle. Currently, however, what's in the implementation requires support for ipv6 for metadata-based tunnels which geneve is: rather than: a) ipv4 + metadata // whether ipv6 compiled or dynamically disabled b) ipv4 + metadata + ipv6 What enforces this in the current 4.4.0-x code when opening a Geneve tunnel is the following in geneve_open() : bool ipv6 = geneve->remote.sa.sa_family == AF_INET6; bool metadata = geneve->collect_md; ... #if IS_ENABLED(CONFIG_IPV6) geneve->sock6 = NULL; if (ipv6 || metadata) ret = geneve_sock_add(geneve, true); #endif if (!ret && (!ipv6 || metadata)) ret = geneve_sock_add(geneve, false); CONFIG_IPV6 is enabled, IPv6 is disabled at boot, but even though ipv6 is false, metadata is always true for a geneve open as it is set unconditionally in ovs: In /lib/dpif_netlink_rtnl.c : case OVS_VPORT_TYPE_GENEVE: nl_msg_put_flag(&request, IFLA_GENEVE_COLLECT_METADATA); The second argument of geneve_sock_add is a boolean value indicating whether it's an ipv6 address family socket or not, and we thus incorrectly pass a true value rather than false. The current "|| metadata" check is unnecessary and incorrectly sends the tunnel creation code down the ipv6 path, which fails subsequently when the code expects an ipv6 family socket. * This issue exists in all versions of the kernel upto present mainline and net-next trees. * Testing with a trivial patch to remove that and make similar changes to those made for vxlan (which had the same issue) has been successful. Patches for various versions to be attached here soon. * Example Versions (bug exists in all versions of Ubuntu and mainline): $ uname -r 4.4.0-135-generic $ lsb_release -rd Description: Ubuntu 16.04.5 LTS Release: 16.04 $ dpkg -l | grep openvswitch-switch ii openvswitch-switch 2.5.4-0ubuntu0.16.04.1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1794232/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : firstname.lastname@example.org Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp