linux-toradex.git/net/ipv6/route.c, branch v4.1.10

ipv6: fix multipath route replace error recovery

2015-10-03T11:49:14+00:00

[ Upstream commit 6b9ea5a64ed5eeb3f68f2e6fcce0ed1179801d1e ]

Problem:
The ecmp route replace support for ipv6 in the kernel, deletes the
existing ecmp route too early, ie when it installs the first nexthop.
If there is an error in installing the subsequent nexthops, its too late
to recover the already deleted existing route leaving the fib
in an inconsistent state.

This patch reduces the possibility of this by doing the following:
a) Changes the existing multipath route add code to a two stage process:
  build rt6_infos + insert them
	ip6_route_add rt6_info creation code is moved into
	ip6_route_info_create.
b) This ensures that most errors are caught during building rt6_infos
  and we fail early
c) Separates multipath add and del code. Because add needs the special
  two stage mode in a) and delete essentially does not care.
d) In any event if the code fails during inserting a route again, a
  warning is printed (This should be unlikely)

Before the patch:
$ip -6 route show
3000:1000:1000:1000::2 via fe80::202:ff:fe00:b dev swp49s0 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:d dev swp49s1 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:f dev swp49s2 metric 1024

/* Try replacing the route with a duplicate nexthop */
$ip -6 route change 3000:1000:1000:1000::2/128 nexthop via
fe80::202:ff:fe00:b dev swp49s0 nexthop via fe80::202:ff:fe00:d dev
swp49s1 nexthop via fe80::202:ff:fe00:d dev swp49s1
RTNETLINK answers: File exists

$ip -6 route show
/* previously added ecmp route 3000:1000:1000:1000::2 dissappears from
 * kernel */

After the patch:
$ip -6 route show
3000:1000:1000:1000::2 via fe80::202:ff:fe00:b dev swp49s0 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:d dev swp49s1 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:f dev swp49s2 metric 1024

/* Try replacing the route with a duplicate nexthop */
$ip -6 route change 3000:1000:1000:1000::2/128 nexthop via
fe80::202:ff:fe00:b dev swp49s0 nexthop via fe80::202:ff:fe00:d dev
swp49s1 nexthop via fe80::202:ff:fe00:d dev swp49s1
RTNETLINK answers: File exists

$ip -6 route show
3000:1000:1000:1000::2 via fe80::202:ff:fe00:b dev swp49s0 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:d dev swp49s1 metric 1024
3000:1000:1000:1000::2 via fe80::202:ff:fe00:f dev swp49s2 metric 1024

Fixes: 27596472473a ("ipv6: fix ECMP route replacement")
Signed-off-by: Roopa Prabhu 
Reviewed-by: Nikolay Aleksandrov 
Acked-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: fix ECMP route replacement

2015-05-20T16:02:26+00:00

When replacing an IPv6 multipath route with "ip route replace", i.e.
NLM_F_CREATE | NLM_F_REPLACE, fib6_add_rt2node() replaces only first
matching route without fixing its siblings, resulting in corrupted
siblings linked list; removing one of the siblings can then end in an
infinite loop.

IPv6 ECMP implementation is a bit different from IPv4 so that route
replacement cannot work in exactly the same way. This should be a
reasonable approximation:

1. If the new route is ECMP-able and there is a matching ECMP-able one
already, replace it and all its siblings (if any).

2. If the new route is ECMP-able and no matching ECMP-able route exists,
replace first matching non-ECMP-able (if any) or just add the new one.

3. If the new route is not ECMP-able, replace first matching
non-ECMP-able route (if any) or add the new route.

We also need to remove the NLM_F_REPLACE flag after replacing old
route(s) by first nexthop of an ECMP route so that each subsequent
nexthop does not replace previous one.

Fixes: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: Michal Kubecek 
Acked-by: Nicolas Dichtel 
Signed-off-by: David S. Miller

ipv6: do not delete previously existing ECMP routes if add fails

2015-05-20T16:02:25+00:00

If adding a nexthop of an IPv6 multipath route fails, comment in
ip6_route_multipath() says we are going to delete all nexthops already
added. However, current implementation deletes even the routes it
hasn't even tried to add yet. For example, running

  ip route add 1234:5678::/64 \
      nexthop via fe80::aa dev dummy1 \
      nexthop via fe80::bb dev dummy1 \
      nexthop via fe80::cc dev dummy1

twice results in removing all routes first command added.

Limit the second (delete) run to nexthops that succeeded in the first
(add) run.

Fixes: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)")
Signed-off-by: Michal Kubecek 
Acked-by: Nicolas Dichtel 
Signed-off-by: David S. Miller

ipv6: Fixed source specific default route handling.

2015-05-09T19:58:41+00:00

If there are only IPv6 source specific default routes present, the
host gets -ENETUNREACH on e.g. connect() because ip6_dst_lookup_tail
calls ip6_route_output first, and given source address any, it fails,
and ip6_route_get_saddr is never called.

The change is to use the ip6_route_get_saddr, even if the initial
ip6_route_output fails, and then doing ip6_route_output _again_ after
we have appropriate source address available.

Note that this is '99% fix' to the problem; a correct fix would be to
do route lookups only within addrconf.c when picking a source address,
and never call ip6_route_output before source address has been
populated.

Signed-off-by: Markus Stenberg 
Signed-off-by: David S. Miller

netlink: implement nla_get_in_addr and nla_get_in6_addr

2015-03-31T17:58:35+00:00

Those are counterparts to nla_put_in_addr and nla_put_in6_addr.

Signed-off-by: Jiri Benc 
Signed-off-by: David S. Miller

netlink: implement nla_put_in_addr and nla_put_in6_addr

2015-03-31T17:58:35+00:00

IP addresses are often stored in netlink attributes. Add generic functions
to do that.

For nla_put_in_addr, it would be nicer to pass struct in_addr but this is
not used universally throughout the kernel, in way too many places __be32 is
used to store IPv4 address.

Signed-off-by: Jiri Benc 
Signed-off-by: David S. Miller

ipv6: coding style: comparison for equality with NULL

2015-03-31T17:51:54+00:00

The ipv6 code uses a mixture of coding styles. In some instances check for NULL
pointer is done as x == NULL and sometimes as !x. !x is preferred according to
checkpatch and this patch makes the code consistent by adopting the latter
form.

No changes detected by objdiff.

Signed-off-by: Ian Morris 
Signed-off-by: David S. Miller

ipv6: expose RFC4191 route preference via rtnetlink

2015-03-12T03:28:09+00:00

This makes it possible to retain the route preference when RAs are handled in
userspace.

Signed-off-by: Lubomir Rintel 
Reviewed-by: Jiri Pirko 
Signed-off-by: David S. Miller

net: Remove protocol from struct dst_ops

2015-03-09T20:06:10+00:00

After my change to neigh_hh_init to obtain the protocol from the
neigh_table there are no more users of protocol in struct dst_ops.
Remove the protocol field from dst_ops and all of it's initializers.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

ipv6: fix ipv6_cow_metrics for non DST_HOST case

2015-02-15T04:26:16+00:00

ipv6_cow_metrics() currently assumes only DST_HOST routes require
dynamic metrics allocation from inetpeer.  The assumption breaks
when ndisc discovered router with RTAX_MTU and RTAX_HOPLIMIT metric.
Refer to ndisc_router_discovery() in ndisc.c and note that dst_metric_set()
is called after the route is created.

This patch creates the metrics array (by calling dst_cow_metrics_generic) in
ipv6_cow_metrics().

Test:
radvd.conf:
interface qemubr0
{
	AdvLinkMTU 1300;
	AdvCurHopLimit 30;

	prefix fd00:face:face:face::/64
	{
		AdvOnLink on;
		AdvAutonomous on;
		AdvRouterAddr off;
	};
};

Before:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec
fe80::/64 dev eth0  proto kernel  metric 256
default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec

After:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec mtu 1300
fe80::/64 dev eth0  proto kernel  metric 256  mtu 1300
default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec mtu 1300 hoplimit 30

Fixes: 8e2ec639173f325 (ipv6: don't use inetpeer to store metrics for routes.)
Signed-off-by: Martin KaFai Lau 
Signed-off-by: David S. Miller