Commit e837735e authored by Nicolas Dichtel's avatar Nicolas Dichtel Committed by David S. Miller
Browse files

ip6_tunnel: ensure to always have a link local address 



When an Xin6 tunnel is set up, we check other netdevices to inherit the link-
local address. If none is available, the interface will not have any link-local
address. RFC4862 expects that each interface has a link local address.

Now than this kind of tunnels supports x-netns, it's easy to fall in this case
(by creating the tunnel in a netns where ethernet interfaces stand and then
moving it to a other netns where no ethernet interface is available).

RFC4291, Appendix A suggests two methods: the first is the one currently
implemented, the second is to generate a unique identifier, so that we can
always generate the link-local address. Let's use eth_random_addr() to generate
this interface indentifier.

I remove completly the previous method, hence for the whole life of the
interface, the link-local address remains the same (previously, it depends on
which ethernet interfaces were up when the tunnel interface was set up).

Signed-off-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7eaa48a4

net/ipv6/addrconf.c

+14 −42
Original line number Diff line number Diff line
@@ -1814,6 +1814,16 @@ static int addrconf_ifid_gre(u8 *eui, struct net_device *dev) 
	return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);

}



static int addrconf_ifid_ip6tnl(u8 *eui, struct net_device *dev)

{

	memcpy(eui, dev->perm_addr, 3);

	memcpy(eui + 5, dev->perm_addr + 3, 3);

	eui[3] = 0xFF;

	eui[4] = 0xFE;

	eui[0] ^= 2;

	return 0;

}



static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)

{

	switch (dev->type) {
@@ -1832,6 +1842,8 @@ static int ipv6_generate_eui64(u8 *eui, struct net_device *dev) 
		return addrconf_ifid_eui64(eui, dev);

	case ARPHRD_IEEE1394:

		return addrconf_ifid_ieee1394(eui, dev);

	case ARPHRD_TUNNEL6:

		return addrconf_ifid_ip6tnl(eui, dev);

	}

	return -1;

}
@@ -2709,7 +2721,8 @@ static void addrconf_dev_config(struct net_device *dev) 
	    (dev->type != ARPHRD_ARCNET) &&

	    (dev->type != ARPHRD_INFINIBAND) &&

	    (dev->type != ARPHRD_IEEE802154) &&

	    (dev->type != ARPHRD_IEEE1394)) {

	    (dev->type != ARPHRD_IEEE1394) &&

	    (dev->type != ARPHRD_TUNNEL6)) {

		/* Alas, we support only Ethernet autoconfiguration. */

		return;

	}
@@ -2795,44 +2808,6 @@ ipv6_inherit_linklocal(struct inet6_dev *idev, struct net_device *link_dev) 
	return -1;

}



static void ip6_tnl_add_linklocal(struct inet6_dev *idev)

{

	struct net_device *link_dev;

	struct net *net = dev_net(idev->dev);



	/* first try to inherit the link-local address from the link device */

	if (idev->dev->iflink &&

	    (link_dev = __dev_get_by_index(net, idev->dev->iflink))) {

		if (!ipv6_inherit_linklocal(idev, link_dev))

			return;

	}

	/* then try to inherit it from any device */

	for_each_netdev(net, link_dev) {

		if (!ipv6_inherit_linklocal(idev, link_dev))

			return;

	}

	pr_debug("init ip6-ip6: add_linklocal failed\n");

}



/*

 * Autoconfigure tunnel with a link-local address so routing protocols,

 * DHCPv6, MLD etc. can be run over the virtual link

 */



static void addrconf_ip6_tnl_config(struct net_device *dev)

{

	struct inet6_dev *idev;



	ASSERT_RTNL();



	idev = addrconf_add_dev(dev);

	if (IS_ERR(idev)) {

		pr_debug("init ip6-ip6: add_dev failed\n");

		return;

	}

	ip6_tnl_add_linklocal(idev);

}



static int addrconf_notify(struct notifier_block *this, unsigned long event,

			   void *ptr)

{
@@ -2900,9 +2875,6 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, 
			addrconf_gre_config(dev);

			break;

#endif

		case ARPHRD_TUNNEL6:

			addrconf_ip6_tnl_config(dev);

			break;

		case ARPHRD_LOOPBACK:

			init_loopback(dev);

			break;

net/ipv6/ip6_tunnel.c

+4 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <linux/netfilter_ipv6.h>

#include <linux/slab.h>

#include <linux/hash.h>

#include <linux/etherdevice.h>



#include <asm/uaccess.h>

#include <linux/atomic.h>
@@ -1471,6 +1472,9 @@ static void ip6_tnl_dev_setup(struct net_device *dev) 
	dev->flags |= IFF_NOARP;

	dev->addr_len = sizeof(struct in6_addr);

	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;

	/* This perm addr will be used as interface identifier by IPv6 */

	dev->addr_assign_type = NET_ADDR_RANDOM;

	eth_random_addr(dev->perm_addr);

}

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