This is an effective no-op in terms of user observable behaviour.

By preventing the overwrite of non-null extra1/extra2 fields
in addrconf_sysctl() we can enable the use of proc_dointvec_minmax().

This allows us to eliminate the constant min/max (1..255) trampoline
function that is addrconf_sysctl_hop_limit().

This is nice because it simplifies the code, and allows future
sysctls with constant min/max limits to also not require trampolines.

We still can't eliminate the trampoline for mtu because it isn't
actually a constant (it depends on other tunables of the device)
and thus requires at-write-time logic to enforce range.
Signed-off-by: NMaciej Żenczykowski <maze@google.com>
Acked-by: NErik Kline <ek@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This implements:
  https://tools.ietf.org/html/rfc7559

Backoff is performed according to RFC3315 section 14:
  https://tools.ietf.org/html/rfc3315#section-14

We allow setting /proc/sys/net/ipv6/conf/*/router_solicitations
to a negative value meaning an unlimited number of retransmits,
and we make this the new default (inline with the RFC).

We also add a new setting:
  /proc/sys/net/ipv6/conf/*/router_solicitation_max_interval
defaulting to 1 hour (per RFC recommendation).
Signed-off-by: NMaciej Żenczykowski <maze@google.com>
Acked-by: NErik Kline <ek@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The parameter items(is always ICMP6_MIB_MAX) is useless for __snmp6_fill_statsdev
Signed-off-by: NJia He <hejianet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In general, when DAD detected IPv6 duplicate address, ifp->state
will be set to INET6_IFADDR_STATE_ERRDAD and DAD is stopped by a
delayed work, the call tree should be like this:

ndisc_recv_ns
  -> addrconf_dad_failure        <- missing ifp put
     -> addrconf_mod_dad_work
       -> schedule addrconf_dad_work()
         -> addrconf_dad_stop()  <- missing ifp hold before call it

addrconf_dad_failure() called with ifp refcont holding but not put.
addrconf_dad_work() call addrconf_dad_stop() without extra holding
refcount. This will not cause any issue normally.

But the race between addrconf_dad_failure() and addrconf_dad_work()
may cause ifp refcount leak and netdevice can not be unregister,
dmesg show the following messages:

IPv6: eth0: IPv6 duplicate address fe80::XX:XXXX:XXXX:XX detected!
...
unregister_netdevice: waiting for eth0 to become free. Usage count = 1

Cc: stable@vger.kernel.org
Fixes: c15b1cca ("ipv6: move DAD and addrconf_verify processing
to workqueue")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All changes are notified, but the initial state was missing.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The 'default' value was not advertised.

Fixes: f3a1bfb1 ("rtnl/ipv6: use netconf msg to advertise forwarding status")
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If DAD fails with accept_dad set to 2, global addresses and host routes
are incorrectly left in place. Even though disable_ipv6 is set,
contrary to documentation, the addresses are not dynamically deleted
from the interface. It is only on a subsequent link down/up that these
are removed. The fix is not only to set the disable_ipv6 flag, but
also to call addrconf_ifdown(), which is the action to carry out when
disabling IPv6. This results in the addresses and routes being deleted
immediately. The DAD failure for the LL addr is determined as before
via netlink, or by the absence of the LL addr (which also previously
would have had to be checked for in case of an intervening link down
and up). As the call to addrconf_ifdown() requires an rtnl lock, the
logic to disable IPv6 when DAD fails is moved to addrconf_dad_work().

Previous behavior:

root@vm1:/# sysctl net.ipv6.conf.eth3.accept_dad=2
net.ipv6.conf.eth3.accept_dad = 2
root@vm1:/# ip -6 addr add 2000::10/64 dev eth3
root@vm1:/# ip link set up eth3
root@vm1:/# ip -6 addr show dev eth3
5: eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
    inet6 2000::10/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:fe43:dd5a/64 scope link tentative dadfailed
       valid_lft forever preferred_lft forever
root@vm1:/# ip -6 route show dev eth3
2000::/64  proto kernel  metric 256
fe80::/64  proto kernel  metric 256
root@vm1:/# ip link set down eth3
root@vm1:/# ip link set up eth3
root@vm1:/# ip -6 addr show dev eth3
root@vm1:/# ip -6 route show dev eth3
root@vm1:/#

New behavior:

root@vm1:/# sysctl net.ipv6.conf.eth3.accept_dad=2
net.ipv6.conf.eth3.accept_dad = 2
root@vm1:/# ip -6 addr add 2000::10/64 dev eth3
root@vm1:/# ip link set up eth3
root@vm1:/# ip -6 addr show dev eth3
root@vm1:/# ip -6 route show dev eth3
root@vm1:/#
Signed-off-by: NMike Manning <mmanning@brocade.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If IPv6 is disabled when the option is set to keep IPv6
addresses on link down, userspace is unaware of this as
there is no such indication via netlink. The solution is to
remove the IPv6 addresses in this case, which results in
netlink messages indicating removal of addresses in the
usual manner. This fix also makes the behavior consistent
with the case of having IPv6 disabled first, which stops
IPv6 addresses from being added.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: NMike Manning <mmanning@brocade.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Using list_move() instead of list_del() + list_add().
Signed-off-by: NWei Yongjun <weiyj.lk@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Default kernel behavior is to delete IPv6 addresses on link
down, which entails deletion of the multicast and the
subnet-router anycast addresses. These deletions do not
happen with sysctl setting to keep global IPv6 addresses on
link down, so every link down/up causes an increment of the
anycast and multicast refcounts. These bogus refcounts may
stop these addrs from being removed on subsequent calls to
delete them. The solution is to leave the groups for the
multicast and subnet anycast on link down for the callflow
when global IPv6 addresses are kept.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: NMike Manning <mmanning@brocade.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All inet6_netconf_notify_devconf() callers are in process context,
so we can use GFP_KERNEL allocations if we take care of not holding
a rwlock while not needed in ip6mr (we hold RTNL there)

Fixes: d67b8c61 ("netconf: advertise mc_forwarding status")
Fixes: f3a1bfb1 ("rtnl/ipv6: use netconf msg to advertise forwarding status")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv6 version of 3f2fb9a8 ("net: l3mdev: address selection should only
consider devices in L3 domain") and the follow up commit, a17b693cdd876
("net: l3mdev: prefer VRF master for source address selection").

That is, if outbound device is given then the address preference order
is an address from that device, an address from the master device if it
is enslaved, and then an address from a device in the same L3 domain.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch exports some neighbour discovery functions which can be used
by 6lowpan neighbour discovery ops functionality then.

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Reviewed-by: NStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: NAlexander Aring <aar@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces neighbour discovery ops callback structure. The
idea is to separate the handling for 6LoWPAN into the 6lowpan module.

These callback offers 6lowpan different handling, such as 802.15.4 short
address handling or RFC6775 (Neighbor Discovery Optimization for IPv6
over 6LoWPANs).

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NAlexander Aring <aar@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch moves the functionality to add a RA PIO prefix generated
address in an own function. This move prepares to add a hook for
adding a second address for a second link-layer address. E.g. short
address for 802.15.4 6LoWPAN.

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Reviewed-by: NStefan Schmidt <stefan@osg.samsung.com>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NAlexander Aring <aar@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the autoconfiguration if a valid 802.15.4 short address
is available for 802.15.4 6LoWPAN interfaces.

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Reviewed-by: NStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: NAlexander Aring <aar@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L3 master devices are virtual devices similar to the loopback
device. Link local and multicast routes for these devices do
not make sense. The ipv6 addrconf code already skips adding a
linklocal address; do the same for the mcast route.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It was a simple idea -- save IPv6 configured addresses on a link down
so that IPv6 behaves similar to IPv4. As always the devil is in the
details and the IPv6 stack as too many behavioral differences from IPv4
making the simple idea more complicated than it needs to be.

The current implementation for keeping IPv6 addresses can panic or spit
out a warning in one of many paths:

1. IPv6 route gets an IPv4 route as its 'next' which causes a panic in
   rt6_fill_node while handling a route dump request.

2. rt->dst.obsolete is set to DST_OBSOLETE_DEAD hitting the WARN_ON in
   fib6_del

3. Panic in fib6_purge_rt because rt6i_ref count is not 1.

The root cause of all these is references related to the host route for
an address that is retained.

So, this patch deletes the host route every time the ifdown loop runs.
Since the host route is deleted and will be re-generated an up there is
no longer a need for the l3mdev fix up. On the 'admin up' side move
addrconf_permanent_addr into the NETDEV_UP event handling so that it
runs only once versus on UP and CHANGE events.

All of the current panics and warnings appear to be related to
addresses on the loopback device, but given the catastrophic nature when
a bug is triggered this patch takes the conservative approach and evicts
all host routes rather than trying to determine when it can be re-used
and when it can not. That can be a later optimizaton if desired.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 841645b5.

Ok, this puts the feature back.  I've decided to apply David A.'s
bug fix and run with that rather than make everyone wait another
whole release for this feature.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts the following three commits:

70af921d
799977d9
f1705ec1

The feature was ill conceived, has terrible semantics, and has added
nothing but regressions to the already fragile ipv6 stack.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Separated from previous patch for readability.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Struct ctl_table_header holds pointer to sysctl table which could be used
for freeing it after unregistration. IPv4 sysctls already use that.
Remove redundant NULL assignment: ndev allocated using kzalloc.

This also saves some bytes: sysctl table could be shorter than
DEVCONF_MAX+1 if some options are disable in config.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

f1705ec1 added the option to retain user configured addresses on an
admin down. A comment to one of the later revisions suggested using the
IFA_F_PERMANENT flag rather than adding a user_managed boolean to the
ifaddr struct. A side effect of this change is that link local and
loopback addresses are also retained which is not part of the objective
of f1705ec1. Add check to drop those addresses.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The original tokenized iid support implemented via f53adae4 ("net: ipv6:
add tokenized interface identifier support") didn't allow for clearing a
device token as it was intended that this addressing mode was the only one
active for globally scoped IPv6 addresses. Later we relaxed that restriction
via 617fe29d ("net: ipv6: only invalidate previously tokenized addresses"),
and we should also allow for clearing tokens as there's no good reason why
it shouldn't be allowed.

Fixes: 617fe29d ("net: ipv6: only invalidate previously tokenized addresses")
Reported-by: NRobin H. Johnson <robbat2@gentoo.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ifupdown2 found a kernel bug with IPv6 routes and movement from the main
table to the VRF table. Sequence of events:

Create the interface and add addresses:
    ip link add dev eth4.105 link eth4 type vlan id 105
    ip addr add dev eth4.105 8.105.105.10/24
    ip -6 addr add dev eth4.105 2008:105:105::10/64

At this point IPv6 has inserted a prefix route in the main table even
though the interface is 'down'. From there the VRF device is created:
    ip link add dev vrf105 type vrf table 105
    ip addr add dev vrf105 9.9.105.10/32
    ip -6 addr add dev vrf105 2000:9:105::10/128
    ip link set vrf105 up

Then the interface is enslaved, while still in the 'down' state:
    ip link set dev eth4.105 master vrf105

Since the device is down the VRF driver cycling the device does not
send the NETDEV_UP and NETDEV_DOWN but rather the NETDEV_CHANGE event
which does not flush the routes inserted prior.

When the link is brought up
    ip link set dev eth4.105 up

the prefix route is added in the VRF table, but does not remove
the route from the main table.

Fix by handling the NETDEV_CHANGEUPPER event similar what was implemented
for IPv4 in 7f49e7a3 ("net: Flush local routes when device changes vrf
association")

Fixes: 35402e31 ("net: Add IPv6 support to VRF device")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds macro NETCONFA_ALL to represent all type of netconf
attributes for IPv4 and IPv6.
Signed-off-by: NZhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andrew and Ying Huang's test robot both reported usage count problems that
trace back to the 'keep address on ifdown' patch.

>From Andrew:
We execute CRIU test on linux-next. On the current linux-next kernel
they hangs on creating a network namespace.

The kernel log contains many massages like this:
[ 1036.122108] unregister_netdevice: waiting for lo to become free.
Usage count = 2
[ 1046.165156] unregister_netdevice: waiting for lo to become free.
Usage count = 2
[ 1056.210287] unregister_netdevice: waiting for lo to become free.
Usage count = 2

I tried to revert this patch and the bug disappeared.

Here is a set of commands to reproduce this bug:

[root@linux-next-test linux-next]# uname -a
Linux linux-next-test 4.5.0-rc6-next-20160301+ #3 SMP Wed Mar 2
17:32:18 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

[root@linux-next-test ~]# unshare -n
[root@linux-next-test ~]# ip link set up dev lo
[root@linux-next-test ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
[root@linux-next-test ~]# logout
[root@linux-next-test ~]# unshare -n

 -----

The problem is a change made to RTM_DELADDR case in __ipv6_ifa_notify that
was added in an early version of the offending patch and is no longer
needed.

Fixes: f1705ec1 ("net: ipv6: Make address flushing on ifdown optional")
Cc: Andrey Wagin <avagin@gmail.com>
Cc: Ying Huang <ying.huang@linux.intel.com>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NJeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit f1705ec1 allows IPv6 addresses to be retained on a link down.
The address can have a cached host route which can point to the wrong
FIB table if the L3 enslavement is changed (e.g., route can point to local
table instead of VRF table if device is added to an L3 domain).

On link up check the table of the cached host route against the FIB
table associated with the device and correct if needed.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, all ipv6 addresses are flushed when the interface is configured
down, including global, static addresses:

    $ ip -6 addr show dev eth1
    3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
        inet6 2100:1::2/120 scope global
           valid_lft forever preferred_lft forever
        inet6 fe80::e0:f9ff:fe79:34bd/64 scope link
           valid_lft forever preferred_lft forever
    $ ip link set dev eth1 down
    $ ip -6 addr show dev eth1
    << nothing; all addresses have been flushed>>

Add a new sysctl to make this behavior optional. The new setting defaults to
flush all addresses to maintain backwards compatibility. When the set global
addresses with no expire times are not flushed on an admin down. The sysctl
is per-interface or system-wide for all interfaces

    $ sysctl -w net.ipv6.conf.eth1.keep_addr_on_down=1
or
    $ sysctl -w net.ipv6.conf.all.keep_addr_on_down=1

Will keep addresses on eth1 on an admin down.

    $ ip -6 addr show dev eth1
    3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
        inet6 2100:1::2/120 scope global
           valid_lft forever preferred_lft forever
        inet6 fe80::e0:f9ff:fe79:34bd/64 scope link
           valid_lft forever preferred_lft forever
    $ ip link set dev eth1 down
    $ ip -6 addr show dev eth1
    3: eth1: <BROADCAST,MULTICAST> mtu 1500 state DOWN qlen 1000
        inet6 2100:1::2/120 scope global tentative
           valid_lft forever preferred_lft forever
        inet6 fe80::e0:f9ff:fe79:34bd/64 scope link tentative
           valid_lft forever preferred_lft forever
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An error response from a RTM_GETNETCONF request can return the positive
error value EINVAL in the struct nlmsgerr that can mislead userspace.
Signed-off-by: NAnton Protopopov <a.s.protopopov@gmail.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In certain 802.11 wireless deployments, there will be NA proxies
that use knowledge of the network to correctly answer requests.
To prevent unsolicitd advertisements on the shared medium from
being a problem, on such deployments wireless needs to drop them.

Enable this by providing an option called "drop_unsolicited_na".
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to solve a problem with 802.11, the so-called hole-196 attack,
add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if
enabled, causes the stack to drop IPv6 unicast packets encapsulated in
link-layer multi- or broadcast frames. Such frames can (as an attack)
be created by any member of the same wireless network and transmitted
as valid encrypted frames since the symmetric key for broadcast frames
is shared between all stations.
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A rcu stall with the following backtrace was seen on a system with
forwarding, optimistic_dad and use_optimistic set. To reproduce,
set these flags and allow ipv6 autoconf.

This occurs because the device write_lock is acquired while already
holding the read_lock. Back trace below -

INFO: rcu_preempt self-detected stall on CPU { 1}  (t=2100 jiffies
 g=3992 c=3991 q=4471)
<6> Task dump for CPU 1:
<2> kworker/1:0     R  running task    12168    15   2 0x00000002
<2> Workqueue: ipv6_addrconf addrconf_dad_work
<6> Call trace:
<2> [<ffffffc000084da8>] el1_irq+0x68/0xdc
<2> [<ffffffc000cc4e0c>] _raw_write_lock_bh+0x20/0x30
<2> [<ffffffc000bc5dd8>] __ipv6_dev_ac_inc+0x64/0x1b4
<2> [<ffffffc000bcbd2c>] addrconf_join_anycast+0x9c/0xc4
<2> [<ffffffc000bcf9f0>] __ipv6_ifa_notify+0x160/0x29c
<2> [<ffffffc000bcfb7c>] ipv6_ifa_notify+0x50/0x70
<2> [<ffffffc000bd035c>] addrconf_dad_work+0x314/0x334
<2> [<ffffffc0000b64c8>] process_one_work+0x244/0x3fc
<2> [<ffffffc0000b7324>] worker_thread+0x2f8/0x418
<2> [<ffffffc0000bb40c>] kthread+0xe0/0xec

v2: do addrconf_dad_kick inside read lock and then acquire write
lock for ipv6_ifa_notify as suggested by Eric

Fixes: 7fd2561e ("net: ipv6: Add a sysctl to make optimistic
addresses useful candidates")

Cc: Eric Dumazet <edumazet@google.com>
Cc: Erik Kline <ek@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The userspace needs to know why is the address being removed so that it can
perhaps obtain a new address.

Without the DADFAILED flag it's impossible to distinguish removal of a
temporary and tentative address due to DAD failure from other reasons (device
removed, manual address removal).
Signed-off-by: NLubomir Rintel <lkundrak@v3.sk>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sysctl performs restrict writes, it allows to write from
a middle position of a sysctl file, which requires us to initialize
the table data before calling proc_dostring() for the write case.

Fixes: 3d1bec99 ("ipv6: introduce secret_stable to ipv6_devconf")
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a new address generator mode, using the stable address generator
with an automatically generated secret. This is intended as a default
address generator mode for device types with no EUI64 implementation.
The new generator is used for ARPHRD_NONE interfaces initially, adding
default IPv6 autoconf support to e.g. tun interfaces.

If the addrgenmode is set to 'random', either by default or manually,
and no stable secret is available, then a random secret is used as
input for the stable-privacy address generator.  The secret can be
read and modified like manually configured secrets, using the proc
interface.  Modifying the secret will change the addrgen mode to
'stable-privacy' to indicate that it operates on a known secret.

Existing behaviour of the 'stable-privacy' mode is kept unchanged. If
a known secret is available when the device is created, then the mode
will default to 'stable-privacy' as before.  The mode can be manually
set to 'random' but it will behave exactly like 'stable-privacy' in
this case. The secret will not change.

Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: 吉藤英明 <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bjørn reported that while we switch all interfaces to privacy stable mode
when setting the secret, we don't set this mode for new interfaces. This
does not make sense, so change this behaviour.

Fixes: 622c81d5 ("ipv6: generation of stable privacy addresses for link-local and autoconf")
Reported-by: NBjørn Mork <bjorn@mork.no>
Cc: Bjørn Mork <bjorn@mork.no>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch removes ARPHRD_IEEE802154 from addrconf handling. In the
earlier days of 802.15.4 6LoWPAN, the interface type was ARPHRD_IEEE802154
which introduced several issues, because 802.15.4 interfaces used the
same type.

Since commit 965e613d ("ieee802154: 6lowpan: fix ARPHRD to
ARPHRD_6LOWPAN") we use ARPHRD_6LOWPAN for 6LoWPAN interfaces. This
patch will remove ARPHRD_IEEE802154 which is currently deadcode, because
ARPHRD_IEEE802154 doesn't reach the minimum 1280 MTU of IPv6.

Also we use 6LoWPAN EUI64 specific defines instead using link-layer
constanst from 802.15.4 link-layer header.

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 64236f3f ("ipv6: introduce IFA_F_STABLE_PRIVACY flag")
failed to update the setting of the IFA_F_OPTIMISTIC flag, causing
the IFA_F_STABLE_PRIVACY flag to be lost if IFA_F_OPTIMISTIC is set.

Cc: Erik Kline <ek@google.com>
Cc: Fernando Gont <fgont@si6networks.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: YOSHIFUJI Hideaki/吉藤英明 <hideaki.yoshifuji@miraclelinux.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Fixes: 64236f3f ("ipv6: introduce IFA_F_STABLE_PRIVACY flag")
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An interface changing type may not have IPv6 addresses. Don't
call the address configuration type change in this case.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>