diff mbox

[v2] net IPv6 : Fix broken IPv6 routing table after loopback down-up

Message ID CAHPKR9J=niSHrGmeX7ZM-1fosjnRA_CFrfd+ha3zwNibNGe1bg@mail.gmail.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Balakumaran Kannan March 28, 2013, 3:14 p.m. UTC 
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'.

Patch is prepared for Linux-3.9.rc4 kernel.

Signed-off-by: Balakumaran Kannan <Balakumaran.Kannan@ap.sony.com>
Signed-off-by: Maruthi Thotad <Maruthi.Thotad@ap.sony.com>
---
==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
$
---
struct in6_addr *addr)
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

David Miller March 29, 2013, 7:17 p.m. UTC | #1 
From: Balakumaran Kannan <kumaran.4353@gmail.com>
Date: Thu, 28 Mar 2013 20:44:36 +0530

>  static void addrconf_add_linklocal(struct inet6_dev *idev, const
> struct in6_addr *addr)

Your email client corrupted this patch, please resubmit but only after
you have emailed the patch to yourself and successfully applied the
patch you receive in that test email.

Thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Balakumaran Kannan March 31, 2013, 6:38 a.m. UTC | #2 
>>  static void addrconf_add_linklocal(struct inet6_dev *idev, const
>> struct in6_addr *addr)
>
> Your email client corrupted this patch, please resubmit but only after
> you have emailed the patch to yourself and successfully applied the
> patch you receive in that test email.
>
> Thanks.

I'll send working patch after verifying it.

Thank you.
K.Balakumaran
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

--- linux-3.9-rc4/net/ipv6/addrconf.c.orig	2013-03-27 10:40:26.382569527 +0530
+++ linux-3.9-rc4/net/ipv6/addrconf.c	2013-03-28 20:33:59.908228232 +0530
@@ -2529,6 +2529,9 @@  static void sit_add_v4_addrs(struct inet
 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 +2543,31 @@  static void init_loopback(struct net_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 (NULL == 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