linux/net/ipv6
Balakumaran Kannan 25fb6ca4ed 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 <Balakumaran.Kannan@ap.sony.com>
Signed-off-by: Maruthi Thotad <Maruthi.Thotad@ap.sony.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-02 14:37:19 -04:00
..
netfilter Merge branch 'master' of git://1984.lsi.us.es/nf 2013-03-20 10:23:52 -04:00
Kconfig Merge branch 'akpm' (incoming from Andrew) 2013-02-21 17:38:49 -08:00
Makefile ipv6: move csum_ipv6_magic() and udp6_csum_init() into static library 2013-01-08 17:56:10 -08:00
addrconf.c net IPv6 : Fix broken IPv6 routing table after loopback down-up 2013-04-02 14:37:19 -04:00
addrconf_core.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
addrlabel.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
af_inet6.c ipv6: Use FIELD_SIZEOF() in inet6_init(). 2013-01-09 23:38:23 -08:00
ah6.c net: Add skb_unclone() helper function. 2013-02-15 15:10:37 -05:00
anycast.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
datagram.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-02-05 14:12:20 -05:00
esp6.c ah6/esp6: set transport header correctly for IPsec tunnel mode. 2013-01-08 12:41:30 +01:00
exthdrs.c ipv6: Store Router Alert option in IP6CB directly. 2013-01-13 20:17:14 -05:00
exthdrs_core.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jesse/openvswitch 2012-11-30 12:01:30 -05:00
exthdrs_offload.c ipv6: Pull IPv6 GSO registration out of the module 2012-11-15 17:39:24 -05:00
fib6_rules.c ipv6: introduce ip6_rt_put() 2012-11-03 14:59:05 -04:00
icmp.c ipv6: Add an error handler for icmp6 2013-01-18 14:19:42 -05:00
inet6_connection_sock.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
inet6_hashtables.c soreuseport: TCP/IPv6 implementation 2013-01-23 13:44:01 -05:00
ip6_checksum.c ipv6: move csum_ipv6_magic() and udp6_csum_init() into static library 2013-01-08 17:56:10 -08:00
ip6_fib.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ip6_flowlabel.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
ip6_gre.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-02-08 18:02:14 -05:00
ip6_input.c ipv6: don't accept node local multicast traffic from the wire 2013-03-29 14:57:33 -04:00
ip6_offload.c v4 GRE: Add TCP segmentation offload for GRE 2013-02-15 15:17:11 -05:00
ip6_offload.h ipv6: Pull IPv6 GSO registration out of the module 2012-11-15 17:39:24 -05:00
ip6_output.c ipv6: don't let node/interface scoped multicast traffic escape on the wire 2013-02-11 14:00:54 -05:00
ip6_tunnel.c ipv6: Introduce ip6_flow_hdr() to fill version, tclass and flowlabel. 2013-01-13 20:17:13 -05:00
ip6mr.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
ipcomp6.c ipv6: Add redirect support to all protocol icmp error handlers. 2012-07-12 00:25:15 -07:00
ipv6_sockglue.c ipv6: rename datagram_send_ctl and datagram_recv_ctl 2013-01-31 13:53:08 -05:00
mcast.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
mip6.c ipv6: mip6: fix mip6_mh_filter() 2012-09-25 16:04:44 -04:00
ndisc.c ndisc: Use compound literals to build redirect message. 2013-01-21 13:33:18 -05:00
netfilter.c netfilter: ipv6: expand skb head in ip6_route_me_harder after oif change 2012-08-30 03:00:15 +02:00
output_core.c ipv6: Update ipv6 static library with newly needed functions 2012-11-15 17:39:23 -05:00
proc.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
protocol.c ipv6: Pull IPv6 GSO registration out of the module 2012-11-15 17:39:24 -05:00
raw.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
reassembly.c inet: limit length of fragment queue hash table bucket lists 2013-03-19 10:28:36 -04:00
route.c net: ipv6: Don't purge default router if accept_ra=2 2013-03-04 14:12:07 -05:00
sit.c ipv6: add anti-spoofing checks for 6to4 and 6rd 2013-01-29 15:22:03 -05:00
syncookies.c tcp: make sysctl_tcp_ecn namespace aware 2013-01-06 21:09:56 -08:00
sysctl_net_ipv6.c net: Enable some sysctls that are safe for the userns root 2012-11-18 20:33:00 -05:00
tcp_ipv6.c tcp: dont handle MTU reduction on LISTEN socket 2013-03-18 13:31:28 -04:00
tcpv6_offload.c net: Remove code duplication between offload structures 2012-11-15 17:39:51 -05:00
tunnel6.c net: ipv6: Standardize prefixes for message logging 2012-05-16 01:01:03 -04:00
udp.c udp: add encap_destroy callback 2013-03-20 12:10:38 -04:00
udp_impl.h net: Make setsockopt() optlen be unsigned. 2009-09-30 16:12:20 -07:00
udp_offload.c v4 GRE: Add TCP segmentation offload for GRE 2013-02-15 15:17:11 -05:00
udplite.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
xfrm6_input.c netfilter: ipv6: use NFPROTO values for NF_HOOK invocation 2010-03-25 16:00:49 +01:00
xfrm6_mode_beet.c ipsec: be careful of non existing mac headers 2012-02-23 16:50:45 -05:00
xfrm6_mode_ro.c
xfrm6_mode_transport.c
xfrm6_mode_tunnel.c ipv6: fix warning in xfrm6_mode_tunnel_input 2013-02-18 12:42:47 -05:00
xfrm6_output.c xfrm6: remove unneeded NULL check in __xfrm6_output() 2012-02-01 02:52:48 -05:00
xfrm6_policy.c xfrm: release neighbor upon dst destruction 2013-02-18 14:57:29 -05:00
xfrm6_state.c ipv6: use IS_ENABLED() 2012-11-01 12:41:35 -04:00
xfrm6_tunnel.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00