Dinesh reported that RTA_MULTIPATH nexthops are 8-bytes larger with IPv6
than IPv4. The recent refactoring for multipath support in netlink
messages does discriminate between non-multipath which needs the OIF
and multipath which adds a rtnexthop struct for each hop making the
RTA_OIF attribute redundant. Resolve by adding a flag to the info
function to skip the oif for multipath.

Fixes: beb1afac ("net: ipv6: Add support to dump multipath routes
       via RTA_MULTIPATH attribute")
Reported-by: NDinesh Dutt <ddutt@cumulusnetworks.com>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Like commit 1f17e2f2 ("net: ipv6: ignore null_entry on route dumps"),
we need to ignore null entry in inet6_rtm_getroute() too.

Return -ENETUNREACH here to sync with IPv4 behavior, as suggested by David.

Fixes: a1a22c12 ("net: ipv6: Keep nexthop of multipath route on admin down")
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andrey reported a NULL pointer deref bug in ipv6_route_ioctl()
-> ip6_route_del() -> __ip6_del_rt_siblings() code path. This is
because ip6_null_entry is returned in this path since ip6_null_entry
is kinda default for a ipv6 route table root node. Quote from
David Ahern:

 ip6_null_entry is the root of all ipv6 fib tables making it integrated
 into the table ...

We should ignore any attempt of trying to delete it, like we do in
__ip6_del_rt() path and several others.
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Fixes: 0ae81335 ("net: ipv6: Allow shorthand delete of all nexthops in multipath route")
Cc: David Ahern <dsa@cumulusnetworks.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This will add stricter validating for RTA_MARK attribute.
Signed-off-by: NLiping Zhang <zlpnobody@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.

The datagram protocols can use MSG_CONFIRM to confirm the
neighbour. When used with MSG_PROBE we do not reach the
code where neighbour is confirmed, so we have to do the
same slow lookup by using the dst_confirm_neigh() helper.
When MSG_PROBE is not used, ip_append_data/ip6_append_data
will set the skb flag dst_pending_confirm.
Reported-by: NYueHaibing <yuehaibing@huawei.com>
Fixes: 5110effe ("net: Do delayed neigh confirmation.")
Fixes: f2bb4bed ("ipv4: Cache output routes in fib_info nexthops.")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add confirm_neigh method to dst_ops and use it from IPv4 and IPv6
to lookup and confirm the neighbour. Its usage via the new helper
dst_confirm_neigh() should be restricted to MSG_PROBE users for
performance reasons.

For XFRM prefer the last tunnel address, if present. With help
from Steffen Klassert.
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ip6_print_replace_route_err logs an error if a route replace fails with
IPv6 addresses in the full format. e.g,:

IPv6: IPV6: multipath route replace failed (check consistency of installed routes): 2001:0db8:0200:0000:0000:0000:0000:0000 nexthop 2001:0db8:0001:0000:0000:0000:0000:0016 ifi 0

Change the message to dump the addresses in the compressed format.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If an entire multipath route is deleted using prefix and len (without any
nexthops), send a single RTM_DELROUTE notification with the full route
using RTA_MULTIPATH. This is done by generating the skb before the route
delete when all of the sibling routes are still present but sending it
after the route has been removed from the FIB. The skip_notify flag
is used to tell the lower fib code not to send notifications for the
individual nexthop routes.

If a route is deleted using RTA_MULTIPATH for any nexthops or a single
nexthop entry is deleted, then the nexthops are deleted one at a time with
notifications sent as each hop is deleted. This is necessary given that
IPv6 allows individual hops within a route to be deleted.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Change ip6_route_multipath_add to send one notifciation with the full
route encoded with RTA_MULTIPATH instead of a series of individual routes.
This is done by adding a skip_notify flag to the nl_info struct. The
flag is used to skip sending of the notification in the fib code that
actually inserts the route. Once the full route has been added, a
notification is generated with all nexthops.

ip6_route_multipath_add handles 3 use cases: new routes, route replace,
and route append. The multipath notification generated needs to be
consistent with the order of the nexthops and it should be consistent
with the order in a FIB dump which means the route with the first nexthop
needs to be used as the route reference. For the first 2 cases (new and
replace), a reference to the route used to send the notification is
obtained by saving the first route added. For the append case, the last
route added is used to loop back to its first sibling route which is
the first nexthop in the multipath route.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv6 returns multipath routes as a series of individual routes making
their display and handling by userspace different and more complicated
than IPv4, putting the burden on the user to see that a route is part of
a multipath route and internally creating a multipath route if desired
(e.g., libnl does this as of commit 29b71371e764). This patch addresses
this difference, allowing multipath routes to be returned using the
RTA_MULTIPATH attribute.

The end result is that IPv6 multipath routes can be treated and displayed
in a format similar to IPv4:

    $ ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:200::/120 metric 1024
	    nexthop via 2001:db8:1::2  dev eth1 weight 1
	    nexthop via 2001:db8:2::2  dev eth2 weight 1
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv4 allows multipath routes to be deleted using just the prefix and
length. For example:
    $ ip ro ls vrf red
    unreachable default metric 8192
    1.1.1.0/24
        nexthop via 10.100.1.254  dev eth1 weight 1
        nexthop via 10.11.200.2  dev eth11.200 weight 1
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

    $ ip ro del 1.1.1.0/24 vrf red

    $ ip ro ls vrf red
    unreachable default metric 8192
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

The same notation does not work with IPv6 because of how multipath routes
are implemented for IPv6. For IPv6 only the first nexthop of a multipath
route is deleted if the request contains only a prefix and length. This
leads to unnecessary complexity in userspace dealing with IPv6 multipath
routes.

This patch allows all nexthops to be deleted without specifying each one
in the delete request. Internally, this is done by walking the sibling
list of the route matching the specifications given (prefix, length,
metric, protocol, etc).

    $  ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:200::/120 via 2001:db8:1::2 dev eth1 metric 1024  pref medium
    2001:db8:200::/120 via 2001:db8:2::2 dev eth2 metric 1024  pref medium
    ...

    $ ip -6 ro del vrf red 2001:db8:200::/120

    $ ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    ...

Because IPv6 allows individual nexthops to be deleted without deleting
the entire route, the ip6_route_multipath_del and non-multipath code
path (ip6_route_del) have to be discriminated so that all nexthops are
only deleted for the latter case. This is done by making the existing
fc_type in fib6_config a u16 and then adding a new u16 field with
fc_delete_all_nh as the first bit.
Suggested-by: NDinesh Dutt <ddutt@cumulusnetworks.com>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv6 stack does not set the protocol for local routes, so those routes show
up with proto "none":
    $ ip -6 ro ls table local
    local ::1 dev lo proto none metric 0  pref medium
    local 2100:3:: dev lo proto none metric 0  pref medium
    local 2100:3::4 dev lo proto none metric 0  pref medium
    local fe80:: dev lo proto none metric 0  pref medium
    ...

Set rt6i_protocol to RTPROT_KERNEL for consistency with IPv4. Now routes
show up with proto "kernel":
    $ ip -6 ro ls table local
    local ::1 dev lo proto kernel metric 0  pref medium
    local 2100:3:: dev lo proto kernel metric 0  pref medium
    local 2100:3::4 dev lo proto kernel metric 0  pref medium
    local fe80:: dev lo proto kernel metric 0  pref medium
    ...
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nothing about lwt state requires a device reference, so remove the
input argument.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

lkp-robot reported a BUG:
[   10.151226] BUG: unable to handle kernel NULL pointer dereference at 00000198
[   10.152525] IP: rt6_fill_node+0x164/0x4b8
[   10.153307] *pdpt = 0000000012ee5001 *pde = 0000000000000000
[   10.153309]
[   10.154492] Oops: 0000 [#1]
[   10.154987] CPU: 0 PID: 909 Comm: netifd Not tainted 4.10.0-rc4-00722-g41e8c70e-dirty #10
[   10.156482] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[   10.158254] task: d0deb000 task.stack: d0e0c000
[   10.159059] EIP: rt6_fill_node+0x164/0x4b8
[   10.159780] EFLAGS: 00010296 CPU: 0
[   10.160404] EAX: 00000000 EBX: d10c2358 ECX: c1f7c6cc EDX: c1f6ff44
[   10.161469] ESI: 00000000 EDI: c2059900 EBP: d0e0dc4c ESP: d0e0dbe4
[   10.162534]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
[   10.163482] CR0: 80050033 CR2: 00000198 CR3: 10d94660 CR4: 000006b0
[   10.164535] Call Trace:
[   10.164993]  ? paravirt_sched_clock+0x9/0xd
[   10.165727]  ? sched_clock+0x9/0xc
[   10.166329]  ? sched_clock_cpu+0x19/0xe9
[   10.166991]  ? lock_release+0x13e/0x36c
[   10.167652]  rt6_dump_route+0x4c/0x56
[   10.168276]  fib6_dump_node+0x1d/0x3d
[   10.168913]  fib6_walk_continue+0xab/0x167
[   10.169611]  fib6_walk+0x2a/0x40
[   10.170182]  inet6_dump_fib+0xfb/0x1e0
[   10.170855]  netlink_dump+0xcd/0x21f

This happens when the loopback device is set down and a ipv6 fib route
dump is requested.

ip6_null_entry is the root of all ipv6 fib tables making it integrated
into the table and hence passed to the ipv6 route dump code. The
null_entry route uses the loopback device for dst.dev but may not have
rt6i_idev set because of the order in which initializations are done --
ip6_route_net_init is run before addrconf_init has initialized the
loopback device. Fixing the initialization order is a much bigger problem
with no obvious solution thus far.

The BUG is triggered when the loopback is set down and the netif_running
check added by a1a22c12 fails. The fill_node descends to checking
rt->rt6i_idev for ignore_routes_with_linkdown and since rt6i_idev is
NULL it faults.

The null_entry route should not be processed in a dump request. Catch
and ignore. This check is done in rt6_dump_route as it is the highest
place in the callchain with knowledge of both the route and the network
namespace.

Fixes: a1a22c12("net: ipv6: Keep nexthop of multipath route on admin down")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove skb_reserve and skb_reset_mac_header from inet6_rtm_getroute. The
allocated skb is not passed through the routing engine (like it is for
IPv4) and has not since the beginning of git time.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv6 deletes route entries associated with multipath routes on an
admin down where IPv4 does not. For example:
    $ ip ro ls vrf red
    unreachable default metric 8192
    1.1.1.0/24 metric 64
            nexthop via 10.100.1.254  dev eth1 weight 1
            nexthop via 10.100.2.254  dev eth2 weight 1
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.4
    10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4

    $ ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2:: dev red proto none metric 0  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024  pref medium
    2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024  pref medium
    ...

Set link down:
    $ ip li set eth1 down

IPv4 retains the multihop route but flags eth1 route as dead:

    $ ip ro ls vrf red
    unreachable default metric 8192
    1.1.1.0/24
            nexthop via 10.100.1.16  dev eth1 weight 1 dead linkdown
            nexthop via 10.100.2.16  dev eth2 weight 1
    10.100.2.0/24 dev eth2 proto kernel scope link src 10.100.2.4

and IPv6 deletes the route as part of flushing all routes for the device:

    $ ip -6 ro ls vrf red
    2001:db8:2:: dev red proto none metric 0  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024  pref medium
    ...

Worse, on admin up of the device the multipath route has to be deleted
to get this leg of the route re-added.

This patch keeps routes that are part of a multipath route if
ignore_routes_with_linkdown is set with the dead and linkdown flags
enabling consistency between IPv4 and IPv6:

    $ ip -6 ro ls vrf red
    2001:db8:2:: dev red proto none metric 0  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:11::/120 via 2001:db8:1::16 dev eth1 metric 1024 dead linkdown  pref medium
    2001:db8:11::/120 via 2001:db8:2::17 dev eth2 metric 1024  pref medium
    ...
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Trying to add an mpls encap route when the MPLS modules are not loaded
hangs. For example:

    CONFIG_MPLS=y
    CONFIG_NET_MPLS_GSO=m
    CONFIG_MPLS_ROUTING=m
    CONFIG_MPLS_IPTUNNEL=m

    $ ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2

The ip command hangs:
root       880   826  0 21:25 pts/0    00:00:00 ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2

    $ cat /proc/880/stack
    [<ffffffff81065a9b>] call_usermodehelper_exec+0xd6/0x134
    [<ffffffff81065efc>] __request_module+0x27b/0x30a
    [<ffffffff814542f6>] lwtunnel_build_state+0xe4/0x178
    [<ffffffff814aa1e4>] fib_create_info+0x47f/0xdd4
    [<ffffffff814ae451>] fib_table_insert+0x90/0x41f
    [<ffffffff814a8010>] inet_rtm_newroute+0x4b/0x52
    ...

modprobe is trying to load rtnl-lwt-MPLS:

root       881     5  0 21:25 ?        00:00:00 /sbin/modprobe -q -- rtnl-lwt-MPLS

and it hangs after loading mpls_router:

    $ cat /proc/881/stack
    [<ffffffff81441537>] rtnl_lock+0x12/0x14
    [<ffffffff8142ca2a>] register_netdevice_notifier+0x16/0x179
    [<ffffffffa0033025>] mpls_init+0x25/0x1000 [mpls_router]
    [<ffffffff81000471>] do_one_initcall+0x8e/0x13f
    [<ffffffff81119961>] do_init_module+0x5a/0x1e5
    [<ffffffff810bd070>] load_module+0x13bd/0x17d6
    ...

The problem is that lwtunnel_build_state is called with rtnl lock
held preventing mpls_init from registering.

Given the potential references held by the time lwtunnel_build_state it
can not drop the rtnl lock to the load module. So, extract the module
loading code from lwtunnel_build_state into a new function to validate
the encap type. The new function is called while converting the user
request into a fib_config which is well before any table, device or
fib entries are examined.

Fixes: 745041e2 ("lwtunnel: autoload of lwt modules")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The prefix arg to rt6_fill_node is non-0 in only 1 path - rt6_dump_route
where a user is requesting a prefix only dump. Simplify rt6_fill_node
by removing the prefix arg and moving the prefix check to rt6_dump_route.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All callers of rt6_fill_node pass 0 for nowait arg. Remove the arg and
simplify rt6_fill_node accordingly.

rt6_fill_node passes the nowait of 0 to ip6mr_get_route. Remove the
nowait arg from it as well.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Handle failure in lwtunnel_fill_encap adding attributes to skb.

Fixes: 571e7226 ("ipv4: support for fib route lwtunnel encap attributes")
Fixes: 19e42e45 ("ipv6: support for fib route lwtunnel encap attributes")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

o s/approriate/appropriate
o s/discouvery/discovery
Signed-off-by: NAlexander Alemayhu <alexander@alemayhu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The protocol field is checked when deleting IPv4 routes, but ignored for
IPv6, which causes problems with routing daemons accidentally deleting
externally set routes (observed by multiple bird6 users).

This can be verified using `ip -6 route del <prefix> proto something`.
Signed-off-by: NMantas Mikulėnas <grawity@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Made kernel accept IPv6 routes with IPv4-mapped address as next-hop.

It is possible to configure IP interfaces with IPv4-mapped addresses, and
one can add IPv6 routes for IPv4-mapped destinations/prefixes, yet prior
to this fix the kernel returned an EINVAL when attempting to add an IPv6
route with an IPv4-mapped address as a nexthop/gateway.

RFC 4798 (a proposed standard RFC) uses IPv4-mapped addresses as nexthops,
thus in order to support that type of address configuration the kernel
needs to allow IPv4-mapped addresses as nexthops.
Signed-off-by: NErik Nordmark <nordmark@arista.com>
Signed-off-by: NBob Gilligan <gilligan@arista.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implemented RFC7527 Enhanced DAD.
IPv6 duplicate address detection can fail if there is some temporary
loopback of Ethernet frames. RFC7527 solves this by including a random
nonce in the NS messages used for DAD, and if an NS is received with the
same nonce it is assumed to be a looped back DAD probe and is ignored.
RFC7527 is enabled by default. Can be disabled by setting both of
conf/{all,interface}/enhanced_dad to zero.
Signed-off-by: NErik Nordmark <nordmark@arista.com>
Signed-off-by: NBob Gilligan <gilligan@arista.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Routes can specify an mtu explicitly or inherit the mtu from
the underlying device - this inheritance is implemented in
dst->ops->mtu handlers ip6_mtu() and ip6_blackhole_mtu().

Currently changing the mtu of a device adds mtu explicitly
to routes using that device.

ie.
  # ip link set dev lo mtu 65536
  # ip -6 route add local 2000::1 dev lo
  # ip -6 route get 2000::1
  local 2000::1 dev lo  table local  src ...  metric 1024  pref medium

  # ip link set dev lo mtu 65535
  # ip -6 route get 2000::1
  local 2000::1 dev lo  table local  src ...  metric 1024  mtu 65535 pref medium

  # ip link set dev lo mtu 65536
  # ip -6 route get 2000::1
  local 2000::1 dev lo  table local  src ...  metric 1024  mtu 65536 pref medium

  # ip -6 route del local 2000::1

After this patch the route entry no longer changes unless it already has an mtu.
There is no need: this inheritance is already done in ip6_mtu()

  # ip link set dev lo mtu 65536
  # ip -6 route add local 2000::1 dev lo
  # ip -6 route add local 2000::2 dev lo mtu 2000
  # ip -6 route get 2000::1; ip -6 route get 2000::2
  local 2000::1 dev lo  table local  src ...  metric 1024  pref medium
  local 2000::2 dev lo  table local  src ...  metric 1024  mtu 2000 pref medium

  # ip link set dev lo mtu 65535
  # ip -6 route get 2000::1; ip -6 route get 2000::2
  local 2000::1 dev lo  table local  src ...  metric 1024  pref medium
  local 2000::2 dev lo  table local  src ...  metric 1024  mtu 2000 pref medium

  # ip link set dev lo mtu 1501
  # ip -6 route get 2000::1; ip -6 route get 2000::2
  local 2000::1 dev lo  table local  src ...  metric 1024  pref medium
  local 2000::2 dev lo  table local  src ...  metric 1024  mtu 1501 pref medium

  # ip link set dev lo mtu 65536
  # ip -6 route get 2000::1; ip -6 route get 2000::2
  local 2000::1 dev lo  table local  src ...  metric 1024  pref medium
  local 2000::2 dev lo  table local  src ...  metric 1024  mtu 65536 pref medium

  # ip -6 route del local 2000::1
  # ip -6 route del local 2000::2

This is desirable because changing device mtu and then resetting it
to the previous value shouldn't change the user visible routing table.
Signed-off-by: NMaciej Żenczykowski <maze@google.com>
CC: Eric Dumazet <edumazet@google.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Use the UID in routing lookups made by protocol connect() and
  sendmsg() functions.
- Make sure that routing lookups triggered by incoming packets
  (e.g., Path MTU discovery) take the UID of the socket into
  account.
- For packets not associated with a userspace socket, (e.g., ping
  replies) use UID 0 inside the user namespace corresponding to
  the network namespace the socket belongs to. This allows
  all namespaces to apply routing and iptables rules to
  kernel-originated traffic in that namespaces by matching UID 0.
  This is better than using the UID of the kernel socket that is
  sending the traffic, because the UID of kernel sockets created
  at namespace creation time (e.g., the per-processor ICMP and
  TCP sockets) is the UID of the user that created the socket,
  which might not be mapped in the namespace.

Tested: compiles allnoconfig, allyesconfig, allmodconfig
Tested: https://android-review.googlesource.com/253302Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Define a new FIB rule attributes, FRA_UID_RANGE, to describe a
  range of UIDs.
- Define a RTA_UID attribute for per-UID route lookups and dumps.
- Support passing these attributes to and from userspace via
  rtnetlink. The value INVALID_UID indicates no UID was
  specified.
- Add a UID field to the flow structures.
Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prior to this patch, ipv6 didn't do mtu lock check in ip6_update_pmtu.
It leaded to that mtu lock doesn't really work when receiving the pkt
of ICMPV6_PKT_TOOBIG.

This patch is to add mtu lock check in __ip6_rt_update_pmtu just as ipv4
did in __ip_rt_update_pmtu.
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similar to IPv4, do not consider link state when validating next hops.

Currently, if the link is down default routes can fail to insert:
 $ ip -6 ro add vrf blue default via 2100:2::64 dev eth2
 RTNETLINK answers: No route to host

With this patch the command succeeds.

Fixes: 8c14586f ("net: ipv6: Use passed in table for nexthop lookups")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rt6_add_route_info and rt6_add_dflt_router were updated to pull the FIB
table from the device index, but the corresponding rt6_get_route_info
and rt6_get_dflt_router functions were not leading to the failure to
process RA's:

    ICMPv6: RA: ndisc_router_discovery failed to add default route

Fix the 'get' functions by using the table id associated with the
device when applicable.

Also, now that default routes can be added to tables other than the
default table, rt6_purge_dflt_routers needs to be updated as well to
look at all tables. To handle that efficiently, add a flag to the table
denoting if it is has a default route via RA.

Fixes: ca254490 ("net: Add VRF support to IPv6 stack")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since the commit below the ipmr/ip6mr rtnl_unicast() code uses the portid
instead of the previous dst_pid which was copied from in_skb's portid.
Since the skb is new the portid is 0 at that point so the packets are sent
to the kernel and we get scheduling while atomic or a deadlock (depending
on where it happens) by trying to acquire rtnl two times.
Also since this is RTM_GETROUTE, it can be triggered by a normal user.

Here's the sleeping while atomic trace:
[ 7858.212557] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
[ 7858.212748] in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/0
[ 7858.212881] 2 locks held by swapper/0/0:
[ 7858.213013]  #0:  (((&mrt->ipmr_expire_timer))){+.-...}, at: [<ffffffff810fbbf5>] call_timer_fn+0x5/0x350
[ 7858.213422]  #1:  (mfc_unres_lock){+.....}, at: [<ffffffff8161e005>] ipmr_expire_process+0x25/0x130
[ 7858.213807] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.0-rc7+ #179
[ 7858.213934] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 7858.214108]  0000000000000000 ffff88005b403c50 ffffffff813a7804 0000000000000000
[ 7858.214412]  ffffffff81a1338e ffff88005b403c78 ffffffff810a4a72 ffffffff81a1338e
[ 7858.214716]  000000000000026c 0000000000000000 ffff88005b403ca8 ffffffff810a4b9f
[ 7858.215251] Call Trace:
[ 7858.215412]  <IRQ>  [<ffffffff813a7804>] dump_stack+0x85/0xc1
[ 7858.215662]  [<ffffffff810a4a72>] ___might_sleep+0x192/0x250
[ 7858.215868]  [<ffffffff810a4b9f>] __might_sleep+0x6f/0x100
[ 7858.216072]  [<ffffffff8165bea3>] mutex_lock_nested+0x33/0x4d0
[ 7858.216279]  [<ffffffff815a7a5f>] ? netlink_lookup+0x25f/0x460
[ 7858.216487]  [<ffffffff8157474b>] rtnetlink_rcv+0x1b/0x40
[ 7858.216687]  [<ffffffff815a9a0c>] netlink_unicast+0x19c/0x260
[ 7858.216900]  [<ffffffff81573c70>] rtnl_unicast+0x20/0x30
[ 7858.217128]  [<ffffffff8161cd39>] ipmr_destroy_unres+0xa9/0xf0
[ 7858.217351]  [<ffffffff8161e06f>] ipmr_expire_process+0x8f/0x130
[ 7858.217581]  [<ffffffff8161dfe0>] ? ipmr_net_init+0x180/0x180
[ 7858.217785]  [<ffffffff8161dfe0>] ? ipmr_net_init+0x180/0x180
[ 7858.217990]  [<ffffffff810fbc95>] call_timer_fn+0xa5/0x350
[ 7858.218192]  [<ffffffff810fbbf5>] ? call_timer_fn+0x5/0x350
[ 7858.218415]  [<ffffffff8161dfe0>] ? ipmr_net_init+0x180/0x180
[ 7858.218656]  [<ffffffff810fde10>] run_timer_softirq+0x260/0x640
[ 7858.218865]  [<ffffffff8166379b>] ? __do_softirq+0xbb/0x54f
[ 7858.219068]  [<ffffffff816637c8>] __do_softirq+0xe8/0x54f
[ 7858.219269]  [<ffffffff8107a948>] irq_exit+0xb8/0xc0
[ 7858.219463]  [<ffffffff81663452>] smp_apic_timer_interrupt+0x42/0x50
[ 7858.219678]  [<ffffffff816625bc>] apic_timer_interrupt+0x8c/0xa0
[ 7858.219897]  <EOI>  [<ffffffff81055f16>] ? native_safe_halt+0x6/0x10
[ 7858.220165]  [<ffffffff810d64dd>] ? trace_hardirqs_on+0xd/0x10
[ 7858.220373]  [<ffffffff810298e3>] default_idle+0x23/0x190
[ 7858.220574]  [<ffffffff8102a20f>] arch_cpu_idle+0xf/0x20
[ 7858.220790]  [<ffffffff810c9f8c>] default_idle_call+0x4c/0x60
[ 7858.221016]  [<ffffffff810ca33b>] cpu_startup_entry+0x39b/0x4d0
[ 7858.221257]  [<ffffffff8164f995>] rest_init+0x135/0x140
[ 7858.221469]  [<ffffffff81f83014>] start_kernel+0x50e/0x51b
[ 7858.221670]  [<ffffffff81f82120>] ? early_idt_handler_array+0x120/0x120
[ 7858.221894]  [<ffffffff81f8243f>] x86_64_start_reservations+0x2a/0x2c
[ 7858.222113]  [<ffffffff81f8257c>] x86_64_start_kernel+0x13b/0x14a

Fixes: 2942e900 ("[RTNETLINK]: Use rtnl_unicast() for rtnetlink unicasts")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 8c14586f ("net: ipv6: Use passed in table for nexthop
lookups") introduced a regression: insertion of an IPv6 route in a table
not containing the appropriate connected route for the gateway but which
contained a non-connected route (like a default gateway) fails while it
was previously working:

    $ ip link add eth0 type dummy
    $ ip link set up dev eth0
    $ ip addr add 2001:db8::1/64 dev eth0
    $ ip route add ::/0 via 2001:db8::5 dev eth0 table 20
    $ ip route add 2001:db8:cafe::1/128 via 2001:db8::6 dev eth0 table 20
    RTNETLINK answers: No route to host
    $ ip -6 route show table 20
    default via 2001:db8::5 dev eth0  metric 1024  pref medium

After this patch, we get:

    $ ip route add 2001:db8:cafe::1/128 via 2001:db8::6 dev eth0 table 20
    $ ip -6 route show table 20
    2001:db8:cafe::1 via 2001:db8::6 dev eth0  metric 1024  pref medium
    default via 2001:db8::5 dev eth0  metric 1024  pref medium

Fixes: 8c14586f ("net: ipv6: Use passed in table for nexthop lookups")
Signed-off-by: NVincent Bernat <vincent@bernat.im>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make ip6_route_input_lookup available outside of ipv6 the module
similar to ip_route_input_noref in the IPv4 world.
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A previous patch added l3mdev flow update making these hooks
redundant. Remove them.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Flip the IPv6 output path to use the l3mdev tx out hook. The VRF dst
is not returned on the first FIB lookup. Instead, the dst on the
skb is switched at the beginning of the IPv6 output processing to
send the packet to the VRF driver on xmit.

Link scope addresses (linklocal and multicast) need special handling:
specifically the oif the flow struct can not be changed because we
want the lookup tied to the enslaved interface. ie., the source address
and the returned route MUST point to the interface scope passed in.
Convert the existing vrf_get_rt6_dst to handle only link scope addresses.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow an L3 master device to act as the loopback for that L3 domain.
For IPv4 the device can also have the address 127.0.0.1.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Today mpls iptunnel lwtunnel_output redirect expects the tunnel
output function to handle fragmentation. This is ok but can be
avoided if we did not do the mpls output redirect too early.
ie we could wait until ip fragmentation is done and then call
mpls output for each ip fragment.

To make this work we will need,
1) the lwtunnel state to carry encap headroom
2) and do the redirect to the encap output handler on the ip fragment
(essentially do the output redirect after fragmentation)

This patch adds tunnel headroom in lwtstate to make sure we
account for tunnel data in mtu calculations during fragmentation
and adds new xmit redirect handler to redirect to lwtunnel xmit func
after ip fragmentation.

This includes IPV6 and some mtu fixes and testing from David Ahern.
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

with the commit 8c14586f ("net: ipv6: Use passed in table for
nexthop lookups"), net hop lookup is first performed on route creation
in the passed-in table.
However device match is not enforced in table lookup, so the found
route can be later discarded due to egress device mismatch and no
global lookup will be performed.
This cause the following to fail:

ip link add dummy1 type dummy
ip link add dummy2 type dummy
ip link set dummy1 up
ip link set dummy2 up
ip route add 2001:db8:8086::/48 dev dummy1 metric 20
ip route add 2001:db8:d34d::/64 via 2001:db8:8086::2 dev dummy1 metric 20
ip route add 2001:db8:8086::/48 dev dummy2 metric 21
ip route add 2001:db8:d34d::/64 via 2001:db8:8086::2 dev dummy2 metric 21
RTNETLINK answers: No route to host

This change fixes the issue enforcing device lookup in
ip6_nh_lookup_table()

v1->v2: updated commit message title

Fixes: 8c14586f ("net: ipv6: Use passed in table for nexthop lookups")
Reported-and-tested-by: NBeniamino Galvani <bgalvani@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

VRF driver needs access to ip6_route_get_saddr code. Since it does
little beyond ipv6_dev_get_saddr and ipv6_dev_get_saddr is already
exported for modules move ip6_route_get_saddr to the header as an
inline.

Code move only; no functional change.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>