When forwarding was set and a new net device is register,
we need add this device to the all-router mcast group.

Signed-off-by: Li Wei <lw@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is a race condition in addrconf_sysctl_forward() and
addrconf_sysctl_disable().
These functions change idev->cnf.forwarding (resp. idev->cnf.disable_ipv6)
and then try to grab the rtnl lock before performing any actions.
If that fails they restore the original value and restart the syscall.
This creates race conditions if ipv6 code tries to access
these parameters, or if multiple instances try to do the same operation.
As an example of the former, if __ipv6_ifa_notify() finds a 0 in
idev->cnf.forwarding when invoked by addrconf_ifdown() it may not free
anycast addresses, ultimately resulting in the net_device not being freed.
This patch reads the user parameters into a temporary location and only
writes the actual parameters when the rtnl lock is acquired.
Tested in 2.6.38.8.
Signed-off-by: Francesco Ruggeri <fruggeri@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This ensures a linear behaviour when filling /proc/net/if_inet6 thus making
ifconfig run really fast on IPv6 only addresses. In fact, with this patch and
the IPv4 one sent a while ago, ifconfig will run in linear time regardless of
address type.

IPv4 related patch: f04565ddf52e401880f8ba51de0dff8ba51c99fd
	 dev: use name hash for dev_seq_ops
	 ...

Some statistics (running ifconfig > /dev/null on a different setup):

iface count / IPv6 no-patch time / IPv6 patched time / IPv4 time
----------------------------------------------------------------
      6250  |       0.23 s       |      0.13 s       |  0.11 s
     12500  |       0.62 s       |      0.28 s       |  0.22 s
     25000  |       2.91 s       |      0.57 s       |  0.46 s
     50000  |      11.37 s       |      1.21 s       |  0.94 s
    128000  |      86.78 s       |      3.05 s       |  2.54 s

Signed-off-by: Mihai Maruseac <mmaruseac@ixiacom.com>
Cc: Daniel Baluta <dbaluta@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Recently Dave noticed that a test we did in ipv6_add_addr to see if we next hop
route for the interface we're adding an addres to was wrong (see commit
7ffbcecbeed91e5874e9a1cfc4c0cbb07dac3069).  for one, it never triggers, and two,
it was completely wrong to begin with.  This test was meant to cover this
section of RFC 4429:

3.3 Modifications to RFC 2462 Stateless Address Autoconfiguration

   * (modifies section 5.5) A host MAY choose to configure a new address
        as an Optimistic Address.  A host that does not know the SLLAO
        of its router SHOULD NOT configure a new address as Optimistic.
        A router SHOULD NOT configure an Optimistic Address.

This patch should bring us into proper compliance with the above clause.  Since
we only add a SLAAC address after we've received a RA which may or may not
contain a source link layer address option, we can pass a pointer to that option
to addrconf_prefix_rcv (which may be null if the option is not present), and
only set the optimistic flag if the option was found in the RA.

Change notes:
(v2) modified the new parameter to addrconf_prefix_rcv to be a bool rather than
a pointer to make its use more clear as per request from davem.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

It just obscures that the netdevice pointer and the expires value are
implemented in the dst_entry sub-object of the ipv6 route.

And it makes grepping for dst_entry member uses much harder too.

Signed-off-by: David S. Miller <davem@davemloft.net>

The route we have here is for the address being added to the interface,
ie. for input packet processing.

Therefore using that route to determine whether an output nexthop gateway
is known and resolved doesn't make any sense.

So, simply remove this test, it never triggered anyways.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-By: Neil Horman <nhorman@tuxdriver.com>

Conflicts:
	drivers/net/ethernet/freescale/fsl_pq_mdio.c
	net/batman-adv/translation-table.c
	net/ipv6/route.c

There is no obvious reason to add a default multicast route for loopback
devices, otherwise there would be a route entry whose dst.error set to
-ENETUNREACH that would blocking all multicast packets.

====================

[ more detailed explanation ]

The problem is that the resulting routing table depends on the sequence
of interface's initialization and in some situation, that would block all
muticast packets. Suppose there are two interfaces on my computer
(lo and eth0), if we initailize 'lo' before 'eth0', the resuting routing
table(for multicast) would be

# ip -6 route show | grep ff00::
unreachable ff00::/8 dev lo metric 256 error -101
ff00::/8 dev eth0 metric 256

When sending multicasting packets, routing subsystem will return the first
route entry which with a error set to -101(ENETUNREACH).

I know the kernel will set the default ipv6 address for 'lo' when it is up
and won't set the default multicast route for it, but there is no reason to
stop 'init' program from setting address for 'lo', and that is exactly what
systemd did.

I am sure there is something wrong with kernel or systemd, currently I preferred
kernel caused this problem.

====================

Signed-off-by: Li Wei <lw@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: David S. Miller <davem@davemloft.net>