mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2025-02-11 22:21:31 +00:00
0ddca6ab09
Until now, the nl_pid of the source address of every message sent by virNetlinkCommand has been set to the value of getpid(). Most of the time this doesn't matter, and in the one case where it does (communication with lldpad), it previously was the proper thing to do, because the netlink event service (which listens on a netlink socket for unsolicited messages from lldpad) coincidentally always happened to bind with a local nl_pid == getpid(). With the fix for: https://bugzilla.redhat.com/show_bug.cgi?id=816465 that particular nl_pid is now effectively a reserved value, so the netlink event service will always bind to something else (coincidentally "getpid() + (1 << 22)", but it really could be anything). The result is that communication between lldpad and libvirtd is broken (lldpad gets a "disconnected" error when it tries to send a directed message). The solution to this problem caused by a solution, is to query the netlink event service's nlhandle for its "local_port", and send that as the source nl_pid (but only when sending to lldpad, of course - in other cases we maintain the old behavior of sending getpid()). There are two cases where a message is being directed at lldpad - one in virNetDevLinkDump, and one in virNetDevVPortProfileOpSetLink. The case of virNetDevVPortProfileOpSetLink is simplest to explain - only if !nltarget_kernel, i.e. the message isn't targetted for the kernel, is the dst_pid set (by calling virNetDevVPortProfileGetLldpadPid()), so only in that case do we call virNetlinkEventServiceLocalPid() to set src_pid. For virNetDevLinkDump, it's a bit more complicated. The call to virNetDevVPortProfileGetLldpadPid() was effectively up one level (in virNetDevVPortProfileOpCommon), although obscured by an unnecessary passing of a function pointer. This patch removes the function pointer, and calls virNetDevVPortProfileGetLldpadPid() directly in virNetDevVPortProfileOpCommon - if it's doing this, it knows that it should also call virNetlinkEventServiceLocalPid() to set src_pid too; then it just passes src_pid and dst_pid down to virNetDevLinkDump. Since (src_pid == 0 && dst_pid == 0) implies that the kernel is the destination, there is no longer any need to send nltarget_kernel as an arg to virNetDevLinkDump, so it's been removed. The disparity between src_pid being int and dst_pid being uint32_t may be a bit disconcerting to some, but I didn't want to complicate virNetlinkEventServiceLocalPid() by having status returned separately from the value. (cherry picked from commit cc0737713a8e1ad37fc9d5393b4ea514f7708138)
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>