[Xen-changelog] [xen-unstable] [LINUX] ipv6: Disable addrconf on Xen bridge device

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1168615387 0
# Node ID c2fd75d7e2b7ab40e98936d10d5c31dbdc37af5b
# Parent  c71fe03f086f8f705bc11b0edc252d71f0a0eb17
[LINUX] ipv6: Disable addrconf on Xen bridge device

The ipv6-no-autoconf patch didn't disable IPv6 addrconf completely.
This means that the Xen bridge device still interfered with normal
IPv6 operation by engaging the IPv6 network with a bogus MAC address.

For details please refer to
        https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=200360

The following patch completely disables IPv6 on the Xen bridge device
by temporarily setting the MTU to a value less than the minimum
allowed for IPv6.

Upstream will provide a cleaner way to disable IPv6 addrconf in
future, possibly in the form of a proc sysctl.  Of course if the Xen
loopback device is removed it would render this change unnecessary.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---
 patches/linux-2.6.16.33/ipv6-no-autoconf.patch |   18 ------------------
 patches/linux-2.6.16.33/series                 |    1 -
 tools/examples/xen-network-common.sh           |    5 +++++
 3 files changed, 5 insertions(+), 19 deletions(-)

diff -r c71fe03f086f -r c2fd75d7e2b7 
patches/linux-2.6.16.33/ipv6-no-autoconf.patch
--- a/patches/linux-2.6.16.33/ipv6-no-autoconf.patch    Fri Jan 12 15:19:23 
2007 +0000
+++ /dev/null   Thu Jan 01 00:00:00 1970 +0000
@@ -1,19 +0,0 @@
-diff -pruN ../orig-linux-2.6.16.29/net/ipv6/addrconf.c ./net/ipv6/addrconf.c
---- ../orig-linux-2.6.16.29/net/ipv6/addrconf.c        2006-09-12 
19:02:10.000000000 +0100
-+++ ./net/ipv6/addrconf.c      2006-09-19 13:59:11.000000000 +0100
-@@ -2471,6 +2471,7 @@ static void addrconf_dad_start(struct in
-       spin_lock_bh(&ifp->lock);
- 
-       if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
-+          !(dev->flags&IFF_MULTICAST) ||
-           !(ifp->flags&IFA_F_TENTATIVE)) {
-               ifp->flags &= ~IFA_F_TENTATIVE;
-               spin_unlock_bh(&ifp->lock);
-@@ -2555,6 +2556,7 @@ static void addrconf_dad_completed(struc
-       if (ifp->idev->cnf.forwarding == 0 &&
-           ifp->idev->cnf.rtr_solicits > 0 &&
-           (dev->flags&IFF_LOOPBACK) == 0 &&
-+          (dev->flags & IFF_MULTICAST) &&
-           (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)) {
-               struct in6_addr all_routers;
- 
diff -r c71fe03f086f -r c2fd75d7e2b7 patches/linux-2.6.16.33/series
--- a/patches/linux-2.6.16.33/series    Fri Jan 12 15:19:23 2007 +0000
+++ b/patches/linux-2.6.16.33/series    Fri Jan 12 15:23:07 2007 +0000
@@ -9,7 +9,6 @@ fix-hz-suspend.patch
 fix-hz-suspend.patch
 fix-ide-cd-pio-mode.patch
 i386-mach-io-check-nmi.patch
-ipv6-no-autoconf.patch
 net-csum.patch
 net-gso-0-base.patch
 net-gso-1-check-dodgy.patch
diff -r c71fe03f086f -r c2fd75d7e2b7 tools/examples/xen-network-common.sh
--- a/tools/examples/xen-network-common.sh      Fri Jan 12 15:19:23 2007 +0000
+++ b/tools/examples/xen-network-common.sh      Fri Jan 12 15:23:07 2007 +0000
@@ -117,7 +117,12 @@ create_bridge () {
         ip link set ${bridge} arp off
         ip link set ${bridge} multicast off
     fi
+
+    # A small MTU disables IPv6 (and therefore IPv6 addrconf).
+    mtu=$(ip link show ${bridge} | sed -n 's/.* mtu \([0-9]\+\).*/\1/p')
+    ip link set ${bridge} mtu 68
     ip link set ${bridge} up
+    ip link set ${bridge} mtu ${mtu:-1500}
 }
 
 # Usage: add_to_bridge bridge dev

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog