Hendrik reported routes in the main table using source address are not
removed when the address is removed. The problem is that fib_sync_down_addr
does not account for devices in the default VRF which are associated
with the main table. Fix by updating the table id reference.
Fixes: 5a56a0b3a4 ("net: Don't delete routes in different VRFs")
Reported-by: Hendrik Donner <hd@os-cillation.de>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When creating a v4 route that uses a v6 nexthop from a nexthop group.
Allow the kernel to properly send the nexthop as v6 via the RTA_VIA
attribute.
Broken behavior:
$ ip nexthop add via fe80::9 dev eth0
$ ip nexthop show
id 1 via fe80::9 dev eth0 scope link
$ ip route add 4.5.6.7/32 nhid 1
$ ip route show
default via 10.0.2.2 dev eth0
4.5.6.7 nhid 1 via 254.128.0.0 dev eth0
10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15
$
Fixed behavior:
$ ip nexthop add via fe80::9 dev eth0
$ ip nexthop show
id 1 via fe80::9 dev eth0 scope link
$ ip route add 4.5.6.7/32 nhid 1
$ ip route show
default via 10.0.2.2 dev eth0
4.5.6.7 nhid 1 via inet6 fe80::9 dev eth0
10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15
$
v2, v3: Addresses code review comments from David Ahern
Fixes: dcb1ecb50e (“ipv4: Prepare for fib6_nh from a nexthop object”)
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Be optimistic about re-using a fib_info when nexthop id is given and
the route does not use metrics. Avoids a memory allocation which in
most cases is expected to be freed anyways.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for RTA_NH_ID attribute to allow a user to specify a
nexthop id to use with a route. fc_nh_id is added to fib_config to
hold the value passed in the RTA_NH_ID attribute. If a nexthop id
is given, the gateway, device, encap and multipath attributes can
not be set.
Update fib_nh_match to check ids on a route delete.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
fix an uninitialized variable:
CC net/ipv4/fib_semantics.o
net/ipv4/fib_semantics.c: In function 'fib_check_nh_v4_gw':
net/ipv4/fib_semantics.c:1027:12: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (!tbl || err) {
^~
Signed-off-by: Enrico Weigelt <info@metux.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some ISDN files that got removed in net-next had some changes
done in mainline, take the removals.
Signed-off-by: David S. Miller <davem@davemloft.net>
IS_ERR() already calls unlikely(), so this extra unlikely() call
around IS_ERR() is not needed.
Signed-off-by: Enrico Weigelt <info@metux.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add 'struct nexthop' and nh_list list_head to fib_info. nh_list is the
fib_info side of the nexthop <-> fib_info relationship.
Add fi_list list_head to 'struct nexthop' to track fib_info entries
using a nexthop instance. Add __remove_nexthop_fib and add it to
__remove_nexthop to walk the new list_head and mark those fib entries
as dead when the nexthop is deleted.
Add a few nexthop helpers for use when a nexthop is added to fib_info:
- nexthop_cmp to determine if 2 nexthops are the same
- nexthop_path_fib_result to select a path for a multipath
'struct nexthop'
- nexthop_fib_nhc to select a specific fib_nh_common within a
multipath 'struct nexthop'
Update existing fib_info_nhc to use nexthop_fib_nhc if a fib_info uses
a 'struct nexthop', and mark fib_info_nh as only used for the non-nexthop
case.
Update the fib_info functions to check for fi->nh and take a different
path as needed:
- free_fib_info_rcu - put the nexthop object reference
- fib_release_info - remove the fib_info from the nexthop's fi_list
- nh_comp - use nexthop_cmp when either fib_info references a nexthop
object
- fib_info_hashfn - use the nexthop id for the hashing vs the oif of
each fib_nh in a fib_info
- fib_nlmsg_size - add space for the RTA_NH_ID attribute
- fib_create_info - verify nexthop reference can be taken, verify
nexthop spec is valid for fib entry, and add fib_info to fi_list for
a nexthop
- fib_select_multipath - use the new nexthop_path_fib_result to select a
path when nexthop objects are used
- fib_table_lookup - if the 'struct nexthop' is a blackhole nexthop, treat
it the same as a fib entry using 'blackhole'
The bulk of the changes are in fib_semantics.c and most of that is
moving the existing change_nexthops into an else branch.
Update the nexthop code to walk fi_list on a nexthop deleted to remove
fib entries referencing it.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert more IPv4 code to use fib_nh_common over fib_nh to enable routes
to use a fib6_nh based nexthop. In the end, only code not using a
nexthop object in a fib_info should directly access fib_nh in a fib_info
without checking the famiy and going through fib_nh_common. Those
functions will be marked when it is not directly evident.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use helpers to access fib_nh and fib_nhs fields of a fib_info. Drop the
fib_dev macro which is an alias for the first nexthop. Replacements:
fi->fib_dev --> fib_info_nh(fi, 0)->fib_nh_dev
fi->fib_nh --> fib_info_nh(fi, 0)
fi->fib_nh[i] --> fib_info_nh(fi, i)
fi->fib_nhs --> fib_info_num_path(fi)
where fib_info_nh(fi, i) returns fi->fib_nh[nhsel] and fib_info_num_path
returns fi->fib_nhs.
Move the existing fib_info_nhc to nexthop.h and define the new ones
there. A later patch adds a check if a fib_info uses a nexthop object,
and defining the helpers in nexthop.h avoid circular header
dependencies.
After this all remaining open coded references to fi->fib_nhs and
fi->fib_nh are in:
- fib_create_info and helpers used to lookup an existing fib_info
entry, and
- the netdev event functions fib_sync_down_dev and fib_sync_up.
The latter two will not be reused for nexthops, and the fib_create_info
will be updated to handle a nexthop in a fib_info.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename nh_update_mtu to fib_nhc_update_mtu and export for use by the
nexthop code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add scope as input argument versus relying on fib_info reference in
fib_nh, and export fib_info_update_nh_saddr.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change fib_check_nh to take net, table and scope as input arguments
over struct fib_config and export for use by nexthop code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to the cached routes, make IPv4 exceptions accessible when
using an IPv6 nexthop struct with IPv4 routes. Simplify the exception
functions by passing in fib_nh_common since that is all it needs,
and then cleanup the call sites that have extraneous fib_nh conversions.
As with the cached routes this is a change in location only, from fib_nh
up to fib_nh_common; no functional change intended.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While the cached routes, nh_pcpu_rth_output and nh_rth_input, are IPv4
specific, a later patch wants to make them accessible for IPv6 nexthops
with IPv4 routes using a fib6_nh. Move the cached routes from fib_nh to
fib_nh_common and update references.
Initialization of the cached entries is moved to fib_nh_common_init,
and free is moved to fib_nh_common_release.
Change in location only, from fib_nh up to fib_nh_common; no functional
change intended.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.
Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().
Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:
@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)
@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
nhc_flags holds the RTNH_F flags for a given nexthop (fib{6}_nh).
All of the RTNH_F_ flags fit in an unsigned char, and since the API to
userspace (rtnh_flags and lower byte of rtm_flags) is 1 byte it can not
grow. Make nhc_flags in fib_nh_common an unsigned char and shrink the
size of the struct by 8, from 56 to 48 bytes.
Update the flags arguments for up netdevice events and fib_nexthop_info
which determines the RTNH_F flags to return on a dump/event. The RTNH_F
flags are passed in the lower byte of rtm_flags which is an unsigned int
so use a temp variable for the flags to fib_nexthop_info and combine
with rtm_flags in the caller.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, lwtunnel_fill_encap hardcodes the encap and encap type
attributes as RTA_ENCAP and RTA_ENCAP_TYPE, respectively. The nexthop
objects want to re-use this code but the encap attributes passed to
userspace as NHA_ENCAP and NHA_ENCAP_TYPE. Since that is the only
difference, change lwtunnel_fill_encap to take the attribute type as
an input.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The header contains rtnh_ macros so rename the file accordingly.
Allows a later patch to use the nexthop.h name for the new
nexthop code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Govindarajulu reported a regression with Network Manager which sends an
RTA_GATEWAY attribute with the address set to 0. Fixup the handling of
RTA_GATEWAY to only set fc_gw_family if the gateway address is actually
set.
Fixes: f35b794b3b ("ipv4: Prepare fib_config for IPv6 gateway")
Reported-by: Govindarajulu Varadarajan <govind.varadar@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for RTA_VIA and allow an IPv6 nexthop for v4 routes:
$ ip ro add 172.16.1.0/24 via inet6 2001:db8::1 dev eth0
$ ip ro ls
...
172.16.1.0/24 via inet6 2001:db8::1 dev eth0
For convenience and simplicity, userspace can use RTA_VIA to specify
AF_INET or AF_INET6 gateway.
The common fib_nexthop_info dump function compares the gateway address
family to the nh_common family to know if the gateway should be encoded
as RTA_VIA or RTA_GATEWAY.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Until support is added to the offload drivers, they need to be able to
reject routes with an IPv6 gateway. To that end add a flag to fib_info
that indicates if any fib_nh has a v6 gateway. The flag allows the drivers
to efficiently know the use of a v6 gateway without walking all fib_nh
tied to a fib_info each time a route is added.
Update mlxsw and rocker to reject the routes with extack message as to why.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helper to use fib6_nh_init to validate a nexthop spec with an IPv6
gateway.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
fib_check_nh is currently huge covering multiple uses cases - device only,
device + gateway, and device + gateway with ONLINK. The next patch adds
validation checks for IPv6 which only further complicates it. So, break
fib_check_nh into 2 helpers - one for gateway validation and one for device
only.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for an IPv6 gateway to fib_config. Since a gateway is either
IPv4 or IPv6, make it a union with fc_gw4 where fc_gw_family decides
which address is in use. Update current checks on family and gw4 to
handle ipv6 as well.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to rtable, fib_config needs to allow the gateway to be either an
IPv4 or an IPv6 address. To that end, rename fc_gw to fc_gw4 to mean an
IPv4 address and add fc_gw_family. Checks on 'is a gateway set' are changed
to see if fc_gw_family is set. In the process prepare the code for a
fc_gw_family == AF_INET6.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow the gateway in a fib_nh_common to be from a different address
family than the outer fib{6}_nh. To that end, replace nhc_has_gw with
nhc_gw_family and update users of nhc_has_gw to check nhc_gw_family.
Now nhc_family is used to know if the nh_common is part of a fib_nh
or fib6_nh (used for container_of to get to route family specific data),
and nhc_gw_family represents the address family for the gateway.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Export fib_nexthop_info and fib_add_nexthop for use by IPv6 code.
Remove rt6_nexthop_info and rt6_add_nexthop in favor of the IPv4
versions. Update fib_nexthop_info for IPv6 linkdown check and
RTA_GATEWAY for AF_INET6.
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the exception of the nexthop weight, the nexthop attributes used by
fib_nexthop_info and fib_add_nexthop come from the fib_nh_common struct.
Update both to use it and change fib_nexthop_info to check the family
as needed.
nexthop weight comes from the common struct for existing use cases, but
for nexthop groups the weight is outside of the fib_nh_common to allow
the same nexthop definition to be used in multiple groups with different
weights.
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to ipv6, move addition of nexthop attributes to dump
message into helpers that are called for both single path and
multipath routes. Align the new helpers to the IPv6 variant
which most notably means computing the flags argument based on
settings in nh_flags.
The RTA_FLOW argument is unique to IPv4, so it is appended after
the new fib_nexthop_info helper. The intent of a later patch is to
make both fib_nexthop_info and fib_add_nexthop usable for both IPv4
and IPv6. This patch is stepping stone in that direction.
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most of the ipv4 code only needs data from fib_nh_common. Add
fib_nh_common selection to fib_result and update users to use it.
Right now, fib_nh_common in fib_result will point to a fib_nh struct
that is embedded within a fib_info:
fib_info --> fib_nh
fib_nh
...
fib_nh
^
fib_result->nhc ----+
Later, nhc can point to a fib_nh within a nexthop struct:
fib_info --> nexthop --> fib_nh
^
fib_result->nhc ---------------+
or for a nexthop group:
fib_info --> nexthop --> nexthop --> fib_nh
nexthop --> fib_nh
...
nexthop --> fib_nh
^
fib_result->nhc ---------------------------+
In all cases nhsel within fib_result will point to which leg in the
multipath route is used.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With fib_nh_common in place, move common initialization and release
code into helpers used by both ipv4 and ipv6. For the moment, the init
is just the lwt encap and the release is both the netdev reference and
the the lwt state reference. More will be added later.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add fib_nh_common struct with common nexthop attributes. Convert
fib_nh and fib6_nh to use it. Use macros to move existing
fib_nh_* references to the new nh_common.nhc_*.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename fib_nh entries that will be moved to a fib_nh_common struct.
Specifically, the device, oif, gateway, flags, scope, lwtstate,
nh_weight and nh_upper_bound are common with all nexthop definitions.
In the process shorten fib_nh_lwtstate to fib_nh_lws to avoid really
long lines.
Rename only; no functional change intended.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the fib_nh cleanup code from free_fib_info_rcu into a new helper,
fib_nh_release. Move classid accounting into fib_nh_release which is
called per fib_nh to make accounting symmetrical with fib_nh_init.
Export the helper to allow for use with nexthop objects in the
future.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consolidate the fib_nh initialization which is duplicated between
fib_create_info for single path and fib_get_nhs for multipath.
Export the helper to allow for use with nexthop objects in the
future.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
in_dev lookup followed by IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN check
is called in several places, some with the rcu lock and others with the
rtnl held.
Move the check to a helper similar to what IPv6 has. Since the helper
can be invoked from either context use rcu_dereference_rtnl to
dereference ip_ptr.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define fib_get_nhs to return EINVAL when CONFIG_IP_ROUTE_MULTIPATH is
not enabled and remove the ifdef check for CONFIG_IP_ROUTE_MULTIPATH
in fib_create_info.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
struct boo entry[];
};
instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add extack argument to ip_fib_metrics_init and add messages for invalid
metrics.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts were easy to resolve using immediate context mostly,
except the cls_u32.c one where I simply too the entire HEAD
chunk.
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 5aad1de5ea ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.
As Stefano described in commit e9fa1495d7 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
- if the local MTU is now lower than the PMTU, that PMTU is now
incorrect
- if the local MTU was the lowest value in the path, and is increased,
we might discover a higher PMTU
Similarly to what commit e9fa1495d7 did for IPv6, update PMTU in those
cases.
If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.
To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.
Fixes: 5aad1de5ea ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the refcounting and potential free of dst metrics associated
with a fib entry to a helper and use it in both ipv4 and ipv6.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consolidate initialization of ipv4 and ipv6 metrics when fib entries
are created into a single helper, ip_fib_metrics_init, that handles
the call to ip_metrics_convert.
If no metrics are defined for the fib entry, then the metrics is set
to dst_default_metrics.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make IPv4 consistent with IPv6 and return an extack message that the
ONLINK flag requires a nexthop device.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David Ahern