Commit 25fb6ca4 authored by Balakumaran Kannan's avatar Balakumaran Kannan Committed by David S. Miller

net IPv6 : Fix broken IPv6 routing table after loopback down-up

IPv6 Routing table becomes broken once we do ifdown, ifup of the loopback(lo)
interface. After down-up, routes of other interface's IPv6 addresses through
'lo' are lost.

IPv6 addresses assigned to all interfaces are routed through 'lo' for internal
communication. Once 'lo' is down, those routing entries are removed from routing
table. But those removed entries are not being re-created properly when 'lo' is
brought up. So IPv6 addresses of other interfaces becomes unreachable from the
same machine. Also this breaks communication with other machines because of
NDISC packet processing failure.

This patch fixes this issue by reading all interface's IPv6 addresses and adding
them to IPv6 routing table while bringing up 'lo'.

==Testing==
Before applying the patch:
$ route -A inet6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2000::20/128                   ::                         U    256 0     0 eth0
fe80::/64                      ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     0 lo
2000::20/128                   ::                         Un   0   1     0 lo
fe80::xxxx:xxxx:xxxx:xxxx/128  ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
$ sudo ifdown lo
$ sudo ifup lo
$ route -A inet6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2000::20/128                   ::                         U    256 0     0 eth0
fe80::/64                      ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
$

After applying the patch:
$ route -A inet6
Kernel IPv6 routing
table
Destination                    Next Hop                   Flag Met Ref Use If
2000::20/128                   ::                         U    256 0     0 eth0
fe80::/64                      ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     0 lo
2000::20/128                   ::                         Un   0   1     0 lo
fe80::xxxx:xxxx:xxxx:xxxx/128  ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
$ sudo ifdown lo
$ sudo ifup lo
$ route -A inet6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2000::20/128                   ::                         U    256 0     0 eth0
fe80::/64                      ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
::1/128                        ::                         Un   0   1     0 lo
2000::20/128                   ::                         Un   0   1     0 lo
fe80::xxxx:xxxx:xxxx:xxxx/128  ::                         Un   0   1     0 lo
ff00::/8                       ::                         U    256 0     0 eth0
::/0                           ::                         !n   -1  1     1 lo
$
Signed-off-by: default avatarBalakumaran Kannan <Balakumaran.Kannan@ap.sony.com>
Signed-off-by: default avatarMaruthi Thotad <Maruthi.Thotad@ap.sony.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f0f6ee1f
......@@ -2529,6 +2529,9 @@ static void sit_add_v4_addrs(struct inet6_dev *idev)
static void init_loopback(struct net_device *dev)
{
struct inet6_dev *idev;
struct net_device *sp_dev;
struct inet6_ifaddr *sp_ifa;
struct rt6_info *sp_rt;
/* ::1 */
......@@ -2540,6 +2543,30 @@ static void init_loopback(struct net_device *dev)
}
add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
/* Add routes to other interface's IPv6 addresses */
for_each_netdev(dev_net(dev), sp_dev) {
if (!strcmp(sp_dev->name, dev->name))
continue;
idev = __in6_dev_get(sp_dev);
if (!idev)
continue;
read_lock_bh(&idev->lock);
list_for_each_entry(sp_ifa, &idev->addr_list, if_list) {
if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
continue;
sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, 0);
/* Failure cases are ignored */
if (!IS_ERR(sp_rt))
ip6_ins_rt(sp_rt);
}
read_unlock_bh(&idev->lock);
}
}
static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr *addr)
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment