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: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 3ca23e89f517a6a2db31a3978957c69c305f4d43..8549a5d0d16795c636429f10610fa3429f708501 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -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;

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index cc3bb201b8b027683d9c8a971e070705d911ed19..d6e00a39274c4d62401b08fd7142338c8fb10c8d 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -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);
 }