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[Qemu-devel] [Bug 761469] [NEW] multicast VPN breaks IPv6 Duplicate Addr
From: |
Neil Wilson |
Subject: |
[Qemu-devel] [Bug 761469] [NEW] multicast VPN breaks IPv6 Duplicate Address Detection |
Date: |
Fri, 15 Apr 2011 07:29:45 -0000 |
Public bug reported:
The multicast VPN facility in Qemu uses Multicast Loopback to make sure
that other Qemu processes on the Host server receive the transmission.
The side effect of this is that the process sending the packet also gets
the packet back on its receive channel and currently this is not
filtered but passed directly to the Virtual Machine.
You can see this effect by running tcpdump in the virtual machine. Every
packet sent appears to be duplicated.
For IPv4 it doesn't appear to cause much of a problem, however with IPv6
the duplicate neighbor solicitation packet is precisely what the system
uses to detect duplicate addresses. So IPv6 addresses fail to establish.
If you run 'ip addr' on a virtual Linux machine with IPv6 enabled you
will see 'dadfailed' next to the link local address. 'ping6' will then
not work.
Checked against 0.12.1.
** Affects: qemu
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/761469
Title:
multicast VPN breaks IPv6 Duplicate Address Detection
Status in QEMU:
New
Bug description:
The multicast VPN facility in Qemu uses Multicast Loopback to make
sure that other Qemu processes on the Host server receive the
transmission. The side effect of this is that the process sending the
packet also gets the packet back on its receive channel and currently
this is not filtered but passed directly to the Virtual Machine.
You can see this effect by running tcpdump in the virtual machine.
Every packet sent appears to be duplicated.
For IPv4 it doesn't appear to cause much of a problem, however with
IPv6 the duplicate neighbor solicitation packet is precisely what the
system uses to detect duplicate addresses. So IPv6 addresses fail to
establish.
If you run 'ip addr' on a virtual Linux machine with IPv6 enabled you
will see 'dadfailed' next to the link local address. 'ping6' will then
not work.
Checked against 0.12.1.
- [Qemu-devel] [PATCH 0/5] PPC: Add FSL (e500) MMU emulation, Alexander Graf, 2011/04/30
- [Qemu-devel] [PATCH 1/5] PPC: Make MPC8544DS obey -cpu switch, Alexander Graf, 2011/04/30
- [Qemu-devel] [PATCH 3/5] PPC: Add GS MSR definition, Alexander Graf, 2011/04/30
- [Qemu-devel] [PATCH 2/5] PPC: Make MPC8544DS emulation work w/o KVM, Alexander Graf, 2011/04/30
- [Qemu-devel] [PATCH 4/5] PPC: Add another 64 bits to instruction feature mask, Alexander Graf, 2011/04/30
- [Qemu-devel] [PATCH 5/5] PPC: Implement e500 (FSL) MMU, Alexander Graf, 2011/04/30