Andrey Konovalov reported crashes in ipv4_mtu()

I could reproduce the issue with KASAN kernels, between
10.246.7.151 and 10.246.7.152 :

1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 &

2) At the same time run following loop :
while :
do
 ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
 ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
done

Cong Wang attempted to add back rt->fi in commit
82486aa6 ("ipv4: restore rt->fi for reference counting")
but this proved to add some issues that were complex to solve.

Instead, I suggested to add a refcount to the metrics themselves,
being a standalone object (in particular, no reference to other objects)

I tried to make this patch as small as possible to ease its backport,
instead of being super clean. Note that we believe that only ipv4 dst
need to take care of the metric refcount. But if this is wrong,
this patch adds the basic infrastructure to extend this to other
families.

Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang
for his efforts on this problem.

Fixes: 2860583f ("ipv4: Kill rt->fi")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add messages for non-obvious errors (e.g, no need to add text for malloc
failures or ENODEV failures). This mostly covers the annoying EINVAL errors
Some message strings violate the 80-columns but searchable strings need to
trump that rule.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Plumb extack argument down to route add functions.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for ECMP hash policy choice via a new sysctl
called fib_multipath_hash_policy and also adds support for L4 hashes.
The current values for fib_multipath_hash_policy are:
 0 - layer 3 (default)
 1 - layer 4
If there's an skb hash already set and it matches the chosen policy then it
will be used instead of being calculated (currently only for L4).
In L3 mode we always calculate the hash due to the ICMP error special
case, the flow dissector's field consistentification should handle the
address order thus we can remove the address reversals.
If the skb is provided we always use it for the hash calculation,
otherwise we fallback to fl4, that is if skb is NULL fl4 has to be set.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a multipath route is hit the kernel doesn't consider nexthops that
are DEAD or LINKDOWN when IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN is set.
Devices that offload multipath routes need to be made aware of nexthop
status changes. Otherwise, the device will keep forwarding packets to
non-functional nexthops.

Add the FIB_EVENT_NH_{ADD,DEL} events to the fib notification chain,
which notify capable devices when they should add or delete a nexthop
from their tables.

Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NAndy Gospodarek <gospo@broadcom.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>

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>

fib_select_path does not call fib_select_multipath if oif is set in the
flow struct. For VRF use cases oif is always set, so multipath route
selection is bypassed. Use the FLOWI_FLAG_SKIP_NH_OIF to skip the oif
check similar to what is done in fib_table_lookup.

Add saddr and proto to the flow struct for the fib lookup done by the
VRF driver to better match hash computation for a flow.

Fixes: 613d09b3 ("net: Use VRF device index for lookups on TX")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_select_default has a single caller within the same file.
Make it static.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.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 FIB notification chain is going to be converted to an atomic chain,
which means switchdev drivers will have to offload FIB entries in
deferred work, as hardware operations entail sleeping.

However, while the work is queued fib info might be freed, so a
reference must be taken. To release the reference (and potentially free
the fib info) fib_info_put() will be called, which in turn calls
free_fib_info().

Export free_fib_info() so that modules will be able to invoke
fib_info_put().
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When deleting an IP address from an interface, there is a clean-up of
routes which refer to this local address. However, there was no check to
see that the VRF matched. This meant that deletion wasn't confined to
the VRF it should have been.

To solve this, a new field has been added to fib_info to hold a table
id. When removing fib entries corresponding to a local ip address, this
table id is also used in the comparison.

The table id is populated when the fib_info is created. This was already
done in some places, but not in ip_rt_ioctl(). This has now been fixed.

Fixes: 021dd3b8 ("net: Add routes to the table associated with the device")
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NMark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes following sparse errors :

net/ipv4/fib_semantics.c:1579:61: warning: incorrect type in argument 2
(different base types)
net/ipv4/fib_semantics.c:1579:61:    expected unsigned int [unsigned]
[usertype] key
net/ipv4/fib_semantics.c:1579:61:    got restricted __be32 const
[usertype] nh_gw

Fixes: a6db4494 ("net: ipv4: Consider failed nexthops in multipath routes")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Vegard Nossum is reporting for a crash in fib_dump_info
when nh_dev = NULL and fib_nhs == 1:

Pid: 50, comm: netlink.exe Not tainted 4.7.0-rc5+
RIP: 0033:[<00000000602b3d18>]
RSP: 0000000062623890  EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000006261b800 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000024 RDI: 000000006245ba00
RBP: 00000000626238f0 R08: 000000000000029c R09: 0000000000000000
R10: 0000000062468038 R11: 000000006245ba00 R12: 000000006245ba00
R13: 00000000625f96c0 R14: 00000000601e16f0 R15: 0000000000000000
Kernel panic - not syncing: Kernel mode fault at addr 0x2e0, ip 0x602b3d18
CPU: 0 PID: 50 Comm: netlink.exe Not tainted 4.7.0-rc5+ #581
Stack:
 626238f0 960226a02 00000400 000000fe
 62623910 600afca7 62623970 62623a48
 62468038 00000018 00000000 00000000
Call Trace:
 [<602b3e93>] rtmsg_fib+0xd3/0x190
 [<602b6680>] fib_table_insert+0x260/0x500
 [<602b0e5d>] inet_rtm_newroute+0x4d/0x60
 [<60250def>] rtnetlink_rcv_msg+0x8f/0x270
 [<60267079>] netlink_rcv_skb+0xc9/0xe0
 [<60250d4b>] rtnetlink_rcv+0x3b/0x50
 [<60265400>] netlink_unicast+0x1a0/0x2c0
 [<60265e47>] netlink_sendmsg+0x3f7/0x470
 [<6021dc9a>] sock_sendmsg+0x3a/0x90
 [<6021e0d0>] ___sys_sendmsg+0x300/0x360
 [<6021fa64>] __sys_sendmsg+0x54/0xa0
 [<6021fac0>] SyS_sendmsg+0x10/0x20
 [<6001ea68>] handle_syscall+0x88/0x90
 [<600295fd>] userspace+0x3fd/0x500
 [<6001ac55>] fork_handler+0x85/0x90

$ addr2line -e vmlinux -i 0x602b3d18
include/linux/inetdevice.h:222
net/ipv4/fib_semantics.c:1264

Problem happens when RTNH_F_LINKDOWN is provided from user space
when creating routes that do not use the flag, catched with
netlink fuzzer.

Currently, the kernel allows user space to set both flags
to nh_flags and fib_flags but this is not intentional, the
assumption was that they are not set. Fix this by rejecting
both flags with EINVAL.
Reported-by: NVegard Nossum <vegard.nossum@oracle.com>
Fixes: 0eeb075f ("net: ipv4 sysctl option to ignore routes when nexthop link is down")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Cc: Andy Gospodarek <gospo@cumulusnetworks.com>
Cc: Dinesh Dutt <ddutt@cumulusnetworks.com>
Cc: Scott Feldman <sfeldma@gmail.com>
Reviewed-by: NAndy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, when creating or updating a route, no check is performed
in both ipv4 and ipv6 code to the hoplimit value.

The caller can i.e. set hoplimit to 256, and when such route will
 be used, packets will be sent with hoplimit/ttl equal to 0.

This commit adds checks for the RTAX_HOPLIMIT value, in both ipv4
ipv6 route code, substituting any value greater than 255 with 255.

This is consistent with what is currently done for ADVMSS and MTU
in the ipv4 code.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Multipath route lookups should consider knowledge about next hops and not
select a hop that is known to be failed.

Example:

                     [h2]                   [h3]   15.0.0.5
                      |                      |
                     3|                     3|
                    [SP1]                  [SP2]--+
                     1  2                   1     2
                     |  |     /-------------+     |
                     |   \   /                    |
                     |     X                      |
                     |    / \                     |
                     |   /   \---------------\    |
                     1  2                     1   2
         12.0.0.2  [TOR1] 3-----------------3 [TOR2] 12.0.0.3
                     4                         4
                      \                       /
                        \                    /
                         \                  /
                          -------|   |-----/
                                 1   2
                                [TOR3]
                                  3|
                                   |
                                  [h1]  12.0.0.1

host h1 with IP 12.0.0.1 has 2 paths to host h3 at 15.0.0.5:

    root@h1:~# ip ro ls
    ...
    12.0.0.0/24 dev swp1  proto kernel  scope link  src 12.0.0.1
    15.0.0.0/16
            nexthop via 12.0.0.2  dev swp1 weight 1
            nexthop via 12.0.0.3  dev swp1 weight 1
    ...

If the link between tor3 and tor1 is down and the link between tor1
and tor2 then tor1 is effectively cut-off from h1. Yet the route lookups
in h1 are alternating between the 2 routes: ping 15.0.0.5 gets one and
ssh 15.0.0.5 gets the other. Connections that attempt to use the
12.0.0.2 nexthop fail since that neighbor is not reachable:

    root@h1:~# ip neigh show
    ...
    12.0.0.3 dev swp1 lladdr 00:02:00:00:00:1b REACHABLE
    12.0.0.2 dev swp1  FAILED
    ...

The failed path can be avoided by considering known neighbor information
when selecting next hops. If the neighbor lookup fails we have no
knowledge about the nexthop, so give it a shot. If there is an entry
then only select the nexthop if the state is sane. This is similar to
what fib_detect_death does.

To maintain backward compatibility use of the neighbor information is
based on a new sysctl, fib_multipath_use_neigh.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A bug report (https://bugzilla.kernel.org/show_bug.cgi?id=107071) noted
that the follwoing ip command is failing with v4.3:

    $ ip route add 10.248.5.0/24 dev bond0.250 table vlan_250 src 10.248.5.154
    RTNETLINK answers: Invalid argument

021dd3b8 changed the lookup of the given preferred source address to
use the table id passed in, but this assumes the local entries are in the
given table which is not necessarily true for non-VRF use cases. When
validating the preferred source fallback to the local table on failure.

Fixes: 021dd3b8 ("net: Add routes to the table associated with the device")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch changes how the multipath hash is computed for locally
generated flows: now the hash comprises l4 information.

This allows better utilization of the available paths when the existing
flows have the same source IP and the same destination IP: with l3 hash,
even when multiple connections are in place simultaneously, a single path
will be used, while with l4 hash we can use all the available paths.

v2 changes:
- use get_hash_from_flowi4() instead of implementing just another l4 hash
  function
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When nexthop is part of multipath route we should clear the
LINKDOWN flag when link goes UP or when first address is added.
This is needed because we always set LINKDOWN flag when DEAD flag
was set but now on UP the nexthop is not dead anymore. Examples when
LINKDOWN bit can be forgotten when no NETDEV_CHANGE is delivered:

- link goes down (LINKDOWN is set), then link goes UP and device
shows carrier OK but LINKDOWN remains set

- last address is deleted (LINKDOWN is set), then address is
added and device shows carrier OK but LINKDOWN remains set

Steps to reproduce:
modprobe dummy
ifconfig dummy0 192.168.168.1 up

here add a multipath route where one nexthop is for dummy0:

ip route add 1.2.3.4 nexthop dummy0 nexthop SOME_OTHER_DEVICE
ifconfig dummy0 down
ifconfig dummy0 up

now ip route shows nexthop that is not dead. Now set the sysctl var:

echo 1 > /proc/sys/net/ipv4/conf/dummy0/ignore_routes_with_linkdown

now ip route will show a dead nexthop because the forgotten
RTNH_F_LINKDOWN is propagated as RTNH_F_DEAD.

Fixes: 8a3d0316 ("net: track link-status of ipv4 nexthops")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When fib_netdev_event calls fib_disable_ip on NETDEV_DOWN event
we should not delete the local routes if the local address
is still present. The confusion comes from the fact that both
fib_netdev_event and fib_inetaddr_event use the NETDEV_DOWN
constant. Fix it by returning back the variable 'force'.

Steps to reproduce:
modprobe dummy
ifconfig dummy0 192.168.168.1 up
ifconfig dummy0 down
ip route list table local | grep dummy | grep host
local 192.168.168.1 dev dummy0  proto kernel  scope host  src 192.168.168.1

Fixes: 8a3d0316 ("net: track link-status of ipv4 nexthops")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This command:
  ip route add 192.168.1.0/24 nexthop via 10.2.1.5 dev eth1 nexthop via 10.2.2.5 dev eth2

generated this suspicious RCU usage message:

[ 63.249262]
[ 63.249939] ===============================
[ 63.251571] [ INFO: suspicious RCU usage. ]
[ 63.253250] 4.3.0-rc3+ #298 Not tainted
[ 63.254724] -------------------------------
[ 63.256401] ../include/linux/inetdevice.h:205 suspicious rcu_dereference_check() usage!
[ 63.259450]
[ 63.259450] other info that might help us debug this:
[ 63.259450]
[ 63.262297]
[ 63.262297] rcu_scheduler_active = 1, debug_locks = 1
[ 63.264647] 1 lock held by ip/2870:
[ 63.265896] #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff813ebfb7>] rtnl_lock+0x12/0x14
[ 63.268858]
[ 63.268858] stack backtrace:
[ 63.270409] CPU: 4 PID: 2870 Comm: ip Not tainted 4.3.0-rc3+ #298
[ 63.272478] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 63.275745] 0000000000000001 ffff8800b8c9f8b8 ffffffff8125f73c ffff88013afcf301
[ 63.278185] ffff8800bab7a380 ffff8800b8c9f8e8 ffffffff8107bf30 ffff8800bb728000
[ 63.280634] ffff880139fe9a60 0000000000000000 ffff880139fe9a00 ffff8800b8c9f908
[ 63.283177] Call Trace:
[ 63.283959] [<ffffffff8125f73c>] dump_stack+0x4c/0x68
[ 63.285593] [<ffffffff8107bf30>] lockdep_rcu_suspicious+0xfa/0x103
[ 63.287500] [<ffffffff8144d752>] __in_dev_get_rcu+0x48/0x4f
[ 63.289169] [<ffffffff8144d797>] fib_rebalance+0x3e/0x127
[ 63.290753] [<ffffffff8144d986>] ? rcu_read_unlock+0x3e/0x5f
[ 63.292442] [<ffffffff8144ea45>] fib_create_info+0xaf9/0xdcc
[ 63.294093] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75
[ 63.295791] [<ffffffff8145236a>] fib_table_insert+0x8c/0x451
[ 63.297493] [<ffffffff8144bf9c>] ? fib_get_table+0x36/0x43
[ 63.299109] [<ffffffff8144c3ca>] inet_rtm_newroute+0x43/0x51
[ 63.300709] [<ffffffff813ef684>] rtnetlink_rcv_msg+0x182/0x195
[ 63.302334] [<ffffffff8107d04c>] ? trace_hardirqs_on+0xd/0xf
[ 63.303888] [<ffffffff813ebfb7>] ? rtnl_lock+0x12/0x14
[ 63.305346] [<ffffffff813ef502>] ? __rtnl_unlock+0x12/0x12
[ 63.306878] [<ffffffff81407c4c>] netlink_rcv_skb+0x3d/0x90
[ 63.308437] [<ffffffff813ec00e>] rtnetlink_rcv+0x21/0x28
[ 63.309916] [<ffffffff81407742>] netlink_unicast+0xfa/0x17f
[ 63.311447] [<ffffffff81407a5e>] netlink_sendmsg+0x297/0x2dc
[ 63.313029] [<ffffffff813c6cd4>] sock_sendmsg_nosec+0x12/0x1d
[ 63.314597] [<ffffffff813c835b>] ___sys_sendmsg+0x196/0x21b
[ 63.316125] [<ffffffff8100bf9f>] ? native_sched_clock+0x1f/0x3c
[ 63.317671] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75
[ 63.319185] [<ffffffff8106c397>] ? sched_clock_cpu+0x9d/0xb6
[ 63.320693] [<ffffffff8107e2d7>] ? __lock_is_held+0x32/0x54
[ 63.322145] [<ffffffff81159fcb>] ? __fget_light+0x4b/0x77
[ 63.323541] [<ffffffff813c8726>] __sys_sendmsg+0x3d/0x5b
[ 63.324947] [<ffffffff813c8751>] SyS_sendmsg+0xd/0x19
[ 63.326274] [<ffffffff814c8f57>] entry_SYSCALL_64_fastpath+0x12/0x6f

It looks like all of the code paths to fib_rebalance are under rtnl.

Fixes: 0e884c78 ("ipv4: L3 hash-based multipath")
Cc: Peter Nørlund <pch@ordbogen.com>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

VRF device needs the same path selection following lookup to set source
address. Rather than duplicating code, move existing code into a
function that is exported to modules.

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

This fixes

net/built-in.o: In function `fib_rebalance':
fib_semantics.c:(.text+0x9df14): undefined reference to `__divdi3'

and

net/built-in.o: In function `fib_rebalance':
net/ipv4/fib_semantics.c:572: undefined reference to `__aeabi_ldivmod'

Fixes: 0e884c78 ("ipv4: L3 hash-based multipath")
Signed-off-by: NPeter Nørlund <pch@ordbogen.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replaces the per-packet multipath with a hash-based multipath using
source and destination address.
Signed-off-by: NPeter Nørlund <pch@ordbogen.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A number of VRF patches used 'int' for table id. It should be u32 to be
consistent with the rest of the stack.

Fixes:
4e3c8992 ("net: Introduce VRF related flags and helpers")
15be405e ("net: Add inet_addr lookup by table")
30bbaa19 ("net: Fix up inet_addr_type checks")
021dd3b8 ("net: Add routes to the table associated with the device")
dc028da5 ("inet: Move VRF table lookup to inlined function")
f6d3c192 ("net: FIB tracepoints")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Reviewed-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, the following case doesn't use DCTCP, even if it should:
A responder has f.e. Cubic as system wide default, but for a specific
route to the initiating host, DCTCP is being set in RTAX_CC_ALGO. The
initiating host then uses DCTCP as congestion control, but since the
initiator sets ECT(0), tcp_ecn_create_request() doesn't set ecn_ok,
and we have to fall back to Reno after 3WHS completes.

We were thinking on how to solve this in a minimal, non-intrusive
way without bloating tcp_ecn_create_request() needlessly: lets cache
the CA ecn option flag in RTAX_FEATURES. In other words, when ECT(0)
is set on the SYN packet, set ecn_ok=1 iff route RTAX_FEATURES
contains the unexposed (internal-only) DST_FEATURE_ECN_CA. This allows
to only do a single metric feature lookup inside tcp_ecn_create_request().

Joint work with Florian Westphal.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Feature bits that are invalid should not be accepted by the kernel,
only the lower 4 bits may be configured, but not the remaining ones.
Even from these 4, 2 of them are unused.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_create_info() is already quite large, so before adding more
code to the metrics section move that to a helper, similar to
ip6_convert_metrics.
Suggested-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add cfg and family arguments to lwt build state functions. cfg is a void
pointer and will either be a pointer to a fib_config or fib6_config
structure. The family parameter indicates which one (either AF_INET
or AF_INET6).

LWT encpasulation implementation may use the fib configuration to build
the LWT state.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andreas reported breakage adding routes with local nexthops:
$ ip route show table main
...
172.28.0.0/24 dev vnf-xe1p0  proto kernel  scope link  src 172.28.0.16

$ ip route add 10.0.0.0/8 via 172.28.0.32 table 100 dev vnf-xe1p0
RTNETLINK answers: Resource temporarily unavailable

3bfd8472 changed the lookup to use the passed in table but for cases like
this the nexthop is in the local table rather than the passed in table.

Fixes: 3bfd8472 ("net: Use passed in table for nexthop lookups")
Reported-by: NAndreas Schultz <aschultz@tpip.net>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make fib_encap_match() static as it isn't used outside the file.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Reviewed-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The built lwtunnel_state struct has to be freed after comparison.

Fixes: 571e7226 ("ipv4: support for fib route lwtunnel encap attributes")
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_lookup() forces FIB_LOOKUP_NOREF flag, while fib_table_lookup()
does not.

This patch solves the typical message at reboot time or device
dismantle :

unregister_netdevice: waiting for eth0 to become free. Usage count = 4

Fixes: 3bfd8472 ("net: Use passed in table for nexthop lookups")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If a user passes in a table for new routes use that table for nexthop
lookups. Specifically, this solves the case where a connected route does
not exist in the main table, but only another table and then a subsequent
route is added with a next hop using the connected route. ie.,

$ ip route ls
default via 10.0.2.2 dev eth0
10.0.2.0/24 dev eth0  proto kernel  scope link  src 10.0.2.15
169.254.0.0/16 dev eth0  scope link  metric 1003
192.168.56.0/24 dev eth1  proto kernel  scope link  src 192.168.56.51

$ ip route ls table 10
1.1.1.0/24 dev eth2  scope link

Without this patch adding a nexthop route fails:

$ ip route add table 10 2.2.2.0/24 via 1.1.1.10
RTNETLINK answers: Network is unreachable

With this patch the route is added successfully.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a device associated with a VRF is brought up or down routes
should be added to/removed from the table associated with the VRF.
fib_magic defaults to using the main or local tables. Have it use
the table with the device if there is one.

A part of this is directing prefsrc validations to the correct
table as well.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently inet_addr_type and inet_dev_addr_type expect local addresses
to be in the local table. With the VRF device local routes for devices
associated with a VRF will be in the table associated with the VRF.
Provide an alternate inet_addr lookup to use a specific table rather
than defaulting to the local table.

inet_addr_type_dev_table keeps the same semantics as inet_addr_type but
if the passed in device is enslaved to a VRF then the table for that VRF
is used for the lookup.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It saves some lines and simplify a bit the code when the state is returning
by this function. It's also useful to handle a NULL entry.

To avoid too long lines, I've also renamed lwtunnel_state_get() and
lwtunnel_state_put() to lwtstate_get() and lwtstate_put().

CC: Thomas Graf <tgraf@suug.ch>
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, we do not notice if new alternative gateways
are added. We can do it by checking for present neigh
entry. Also, gateways that are currently probed (NUD_INCOMPLETE)
can be skipped from round-robin probing.
Suggested-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_select_default considers alternative routes only when
res->fi is for the first alias in res->fa_head. In the
common case this can happen only when the initial lookup
matches the first alias with highest TOS value. This
prevents the alternative routes to require specific TOS.

This patch solves the problem as follows:

- routes that require specific TOS should be returned by
fib_select_default only when TOS matches, as already done
in fib_table_lookup. This rule implies that depending on the
TOS we can have many different lists of alternative gateways
and we have to keep the last used gateway (fa_default) in first
alias for the TOS instead of using single tb_default value.

- as the aliases are ordered by many keys (TOS desc,
fib_priority asc), we restrict the possible results to
routes with matching TOS and lowest metric (fib_priority)
and routes that match any TOS, again with lowest metric.

For example, packet with TOS 8 can not use gw3 (not lowest
metric), gw4 (different TOS) and gw6 (not lowest metric),
all other gateways can be used:

tos 8 via gw1 metric 2 <--- res->fa_head and res->fi
tos 8 via gw2 metric 2
tos 8 via gw3 metric 3
tos 4 via gw4
tos 0 via gw5
tos 0 via gw6 metric 1
Reported-by: NHagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_trie starting from 4.1 can link fib aliases from
different prefixes in same list. Make sure the alternative
gateways are in same table and for same prefix (0) by
checking tb_id and fa_slen.

Fixes: 79e5ad2c ("fib_trie: Remove leaf_info")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>