Commit fc882fcf authored Aug 03, 2017 by Ido Schimmel Committed by David S. Miller Aug 03, 2017

ipv6: Regenerate host route according to node pointer upon interface up



When an interface is brought back up, the kernel tries to restore the
host routes tied to its permanent addresses.

However, if the host route was removed from the FIB, then we need to
reinsert it. This is done by releasing the current dst and allocating a
new, so as to not reuse a dst with obsolete values.

Since this function is called under RTNL and using the same explanation
from the previous patch, we can test if the route is in the FIB by
checking its node pointer instead of its reference count.

Tested using the following script and Andrey's reproducer mentioned
in commit 8048ced9 ("net: ipv6: regenerate host route if moved to gc
list") and linked below:

$ ip link set dev lo up
$ ip link add dummy1 type dummy
$ ip -6 address add cafe::1/64 dev dummy1
$ ip link set dev lo down	# cafe::1/128 is removed
$ ip link set dev dummy1 up
$ ip link set dev lo up

The host route is correctly regenerated.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Link: http://lkml.kernel.org/r/CAAeHK+zSe82vc5gCRgr_EoUwiALPnWVdWJBPwJZBpbxYz=kGJw@mail.gmail.com


Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 9217d8c2

net/ipv6/addrconf.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3321,11 +3321,11 @@ static void addrconf_gre_config(struct net_device *dev)
		static int fixup_permanent_addr(struct inet6_dev *idev,
		struct inet6_ifaddr *ifp)
		{
		/* rt6i_ref == 0 means the host route was removed from the
		/* !rt6i_node means the host route was removed from the
		* FIB, for example, if 'lo' device is taken down. In that
		* case regenerate the host route.
		*/
		if (!ifp->rt \|\| !atomic_read(&ifp->rt->rt6i_ref)) {
		if (!ifp->rt \|\| !ifp->rt->rt6i_node) {
		struct rt6_info rt, prev;

		rt = addrconf_dst_alloc(idev, &ifp->addr, false);

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