From 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f Mon Sep 17 00:00:00 2001 From: Balakumaran Kannan Date: Tue, 2 Apr 2013 16:15:05 +0530 Subject: [PATCH] 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: Balakumaran Kannan Signed-off-by: Maruthi Thotad Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 26512250e095..a459c4f5b769 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -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) -- GitLab