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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>
This commit is contained in:
Nicolas Dichtel 2013-08-20 12:16:06 +02:00 committed by David S. Miller
parent 7eaa48a45c
commit e837735ec4
2 changed files with 18 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
net/ipv6/addrconf.c
View File

@ -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;

4
net/ipv6/ip6_tunnel.c
View File

@ -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);
}