* [PATCH] net : Fix broken IPv6 routing table after loopback down-up
@ 2013-03-27 10:01 Balakumaran Kannan
2013-03-27 10:55 ` YOSHIFUJI Hideaki
0 siblings, 1 reply; 3+ messages in thread
From: Balakumaran Kannan @ 2013-03-27 10:01 UTC (permalink / raw)
To: davem, kuznet, jmorris, yoshfuji, kaber
Cc: netdev, Balakumaran.Kannan, maruthi.thotad
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.sm.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
$
---
--- 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 2013-03-27 10:56:45.227354856 +0530
@@ -2529,6 +2529,11 @@ 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 list_head *sp_ifap;
+ struct rt6_info *sp_rt;
+ int i = 1;
/* ::1 */
@@ -2540,6 +2545,27 @@ static void init_loopback(struct net_dev
}
add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
+
+ while ((sp_dev = dev_get_by_index(dev_net(dev), i++))) {
+
+ if (!strcmp(sp_dev->name, dev->name)) {
+ dev_put(sp_dev);
+ continue;
+ }
+
+ idev = ipv6_find_idev(sp_dev);
+ dev_put(sp_dev);
+ if (NULL == idev)
+ continue;
+
+ list_for_each(sp_ifap, &idev->addr_list) {
+ sp_ifa = list_entry(sp_ifap, struct inet6_ifaddr,
+ if_list);
+ sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, 0);
+ if (!IS_ERR(sp_rt))
+ ip6_ins_rt(sp_rt);
+ }
+ }
}
static void addrconf_add_linklocal(struct inet6_dev *idev, const
struct in6_addr *addr)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net : Fix broken IPv6 routing table after loopback down-up
2013-03-27 10:01 [PATCH] net : Fix broken IPv6 routing table after loopback down-up Balakumaran Kannan
@ 2013-03-27 10:55 ` YOSHIFUJI Hideaki
2013-03-27 15:26 ` Eric Dumazet
0 siblings, 1 reply; 3+ messages in thread
From: YOSHIFUJI Hideaki @ 2013-03-27 10:55 UTC (permalink / raw)
To: Balakumaran Kannan
Cc: davem, kuznet, jmorris, kaber, netdev, Balakumaran.Kannan,
maruthi.thotad, YOSHIFUJI Hideaki
Balakumaran Kannan wrote:
> 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.sm.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
> $
> ---
> --- 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 2013-03-27 10:56:45.227354856 +0530
> @@ -2529,6 +2529,11 @@ 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 list_head *sp_ifap;>
> static void addrconf_add_linklocal(struct inet6_dev *idev, const
> 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
>
> + struct rt6_info *sp_rt;
> + int i = 1;
>
> /* ::1 */
>
> @@ -2540,6 +2545,27 @@ static void init_loopback(struct net_dev
> }
>
> add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
> +
> + while ((sp_dev = dev_get_by_index(dev_net(dev), i++))) {
> +
I think this cannot work because we may have missing index.
Why no dev_get_by_name()?
> + if (!strcmp(sp_dev->name, dev->name)) {
> + dev_put(sp_dev);
> + continue;
> + }
> +
> + idev = ipv6_find_idev(sp_dev);
> + dev_put(sp_dev);
> + if (NULL == idev)
> + continue;
> +
> + list_for_each(sp_ifap, &idev->addr_list) {
> + sp_ifa = list_entry(sp_ifap, struct inet6_ifaddr,
> + if_list);
> + sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, 0);
> + if (!IS_ERR(sp_rt))
> + ip6_ins_rt(sp_rt);
> + }
> + }
> }
lock?
--yoshfuji
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net : Fix broken IPv6 routing table after loopback down-up
2013-03-27 10:55 ` YOSHIFUJI Hideaki
@ 2013-03-27 15:26 ` Eric Dumazet
0 siblings, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2013-03-27 15:26 UTC (permalink / raw)
To: YOSHIFUJI Hideaki
Cc: Balakumaran Kannan, davem, kuznet, jmorris, kaber, netdev,
Balakumaran.Kannan, maruthi.thotad
On Wed, 2013-03-27 at 19:55 +0900, YOSHIFUJI Hideaki wrote:
> Balakumaran Kannan wrote:
> > add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
> > +
> > + while ((sp_dev = dev_get_by_index(dev_net(dev), i++))) {
> > +
>
> I think this cannot work because we may have missing index.
> Why no dev_get_by_name()?
I might 'work' because lo interface index is 1 on all network
namespaces.
But yes, this ugly loop is not needed at all.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-03-27 15:26 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-03-27 10:01 [PATCH] net : Fix broken IPv6 routing table after loopback down-up Balakumaran Kannan
2013-03-27 10:55 ` YOSHIFUJI Hideaki
2013-03-27 15:26 ` Eric Dumazet
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).