No longer needed. TCP writes metrics, but now in it's own special
cache that does not dirty the route metrics. Therefore there is no
longer any reason to pre-cow metrics in this way.
Signed-off-by: David S. Miller <davem@davemloft.net>
Maintain a local hash table of TCP dynamic metrics blobs.
Computed TCP metrics are no longer maintained in the route metrics.
The table uses RCU and an extremely simple hash so that it has low
latency and low overhead. A simple hash is legitimate because we only
make metrics blobs for fully established connections.
Some tweaking of the default hash table sizes, metric timeouts, and
the hash chain length limit certainly could use some tweaking. But
the basic design seems sound.
With help from Eric Dumazet and Joe Perches.
Signed-off-by: David S. Miller <davem@davemloft.net>
A lot of code has either the memset or an inefficient copy
from a static array that contains the all-ones broadcast
address. Introduce eth_broadcast_addr() to fill an address
with all ones, making the code clearer and allowing us to
get rid of some constant arrays.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All paths assume, when CONFIG_IP_MULTIPLE_TABLES is enabled, that any
successful call to fib_lookup() will initialize the fib_result->r
value to something.
We violated that expectation in the new fib_lookup() fast path.
Reported-by: Or Gerlitz <ogerlitz@mellanox.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If registering of one of them fails, all already registered drivers
of this module will be unregistered.
Use the new register/unregister functions in all drivers
registering more than one driver.
amd.c, realtek.c: Simplify: directly return registration result.
Tested with broadcom.c
All others compile-tested.
Signed-off-by: Christian Hohnstaedt <chohnstaedt@innominate.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The device managed flow steering API has three promiscuous modes:
1. Uplink - captures all the packets that arrive to the port.
2. Allmulti - captures all multicast packets arriving to the port.
3. Function port - for future use, this mode is not implemented yet.
Use these modes with the flow_attach and flow_detach firmware commands
according to the promiscuous state of the netdevice.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The driver is modified to support three operation modes.
If supported by firmware use the device managed flow steering
API, that which we call device managed steering mode. Else, if
the firmware supports the B0 steering mode use it, and finally,
if none of the above, use the A0 steering mode.
When the steering mode is device managed, the code is modified
such that L2 based rules set by the mlx4_en driver for Ethernet
unicast and multicast, and the IB stack multicast attach calls
done through the mlx4_ib driver are all routed to use the device
managed API.
When attaching rule using device managed flow steering API,
the firmware returns a 64 bit registration id, which is to be
provided during detach.
Currently the firmware is always programmed during HCA initialization
to use standard L2 hashing. Future work should be done to allow
configuring the flow-steering hash function with common, non
proprietary means.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for firmware commands to attach/detach a new device managed
steering mode. Such network steering rules allow the user to provide an
L2/L3/L4 flow specification to the firmware and have the device to steer
traffic that matches that specification to the provided QP.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of checking the firmware supported steering mode in various
places in the code, add a dedicated field in the mlx4 device capabilities
structure which is written once during the initialization flow and read
across the code.
This also set the grounds for add new steering modes. Currently two modes
are supported, and are named after the ConnectX HW versions A0 and B0.
A0 steering uses mac_index, vlan_index and priority to steer traffic
into pre-defined range of QPs.
B0 steering uses Ethernet L2 hashing rules and is enabled only
if the firmware supports both unicast and multicast B0 steering,
The current steering modes are relevant for Ethernet traffic only,
such that Infiniband steering remains untouched.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the user hasn't actually installed any custom rules, or fiddled
with the default ones, don't go through the whole FIB rules layer.
It's just pure overhead.
Instead do what we do with CONFIG_IP_MULTIPLE_TABLES disabled, check
the individual tables by hand, one by one.
Also, move fib_num_tclassid_users into the ipv4 network namespace.
Signed-off-by: David S. Miller <davem@davemloft.net>
Most multi-queue networking driver consider the number of online cpus when
configuring RSS queues.
This patch adds a wrapper to the number of cpus, setting an upper limit on the
number of cpus a driver should consider (by default) when allocating resources
for his queues.
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This makes for a simplified conversion away from dst_get_neighbour*().
All code outside of ipv6 will use neigh lookups via dst_neigh_lookup*().
Signed-off-by: David S. Miller <davem@davemloft.net>
Causes the handler to use the daddr in the ipv4/ipv6 header when
the route gateway is unspecified (local subnet).
Signed-off-by: David S. Miller <davem@davemloft.net>
When a dst_confirm() happens, mark the confirmation as pending in the
dst. Then on the next packet out, when we have the neigh in-hand, do
the update.
This removes the dependency in dst_confirm() of dst's having an
attached neigh.
While we're here, remove the explicit 'dst' NULL check, all except 2
or 3 call sites ensure it's not NULL. So just fix those cases up.
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow setting of only supported flag bits in queue->flags.
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch generalizes nf_ct_l4proto_net by splitting it into chunks and
moving the corresponding protocol part to where it really belongs to.
To clarify, note that we follow two different approaches to support per-net
depending if it's built-in or run-time loadable protocol tracker.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
This ematch makes it possible to classify CAN frames (AF_CAN) according
to their identifiers. This functionality can not be easily achieved with
existing classifiers, such as u32, because CAN identifier is always stored
in native endianness, whereas u32 expects Network byte order.
Signed-off-by: Rostislav Lisovy <lisovy@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Pull networking update from David Miller:
1) Fix RX sequence number handling in mwifiex, from Stone Piao.
2) Netfilter ipset mis-compares device names, fix from Florian
Westphal.
3) Fix route leak in ipv6 IPVS, from Eric Dumazet.
4) NFS fixes. Several buffer overflows in NCI layer from Dan
Rosenberg, and release sock OOPS'er fix from Eric Dumazet.
5) Fix WEP handling ath9k, we started using a bit the chip provides to
indicate undecrypted packets but that bit turns out to be unreliable
in certain configurations. Fix from Felix Fietkau.
6) Fix Kconfig dependency bug in wlcore, from Randy Dunlap.
7) New USB IDs for rtlwifi driver from Larry Finger.
8) Fix crashes in qmi_wwan usbnet driver when disconnecting, from Bjørn
Mork.
9) Gianfar driver programs coalescing settings properly in single queue
mode, but does not do so in multi-queue mode. Fix from Claudiu
Manoil.
10) Missing module.h include in davinci_cpdma.c, from Daniel Mack.
11) Need dummy handler for IPSET_CMD_NONE otherwise we crash in ipset if
we get this via nfnetlink, fix from Tomasz Bursztyka.
12) Missing RCU unlock in nfnetlink error path, also from Tomasz.
13) Fix divide by zero in igbvf when the user tries to set an RX
coalescing value of 0 usecs, from Mitch A Williams.
14) We can process SCTP sacks for the wrong transport, oops. Fix from
Neil Horman.
15) Remove hw IP payload checksumming from e1000e driver. This has zery
value in our stack, and turning it on creates a very unintuitive
restriction for users when using jumbo MTUs.
Specifically, when IP payload checksums are on you cannot use both
receive hashing offload and jumbo MTU. Fix from Bruce Allan.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (27 commits)
e1000e: remove use of IP payload checksum
sctp: be more restrictive in transport selection on bundled sacks
igbvf: fix divide by zero
netfilter: nfnetlink: fix missing rcu_read_unlock in nfnetlink_rcv_msg
netfilter: ipset: fix crash if IPSET_CMD_NONE command is sent
davinci_cpdma: include linux/module.h
gianfar: Fix RXICr/TXICr programming for multi-queue mode
net: Downgrade CAP_SYS_MODULE deprecated message from error to warning.
net: qmi_wwan: fix Oops while disconnecting
mwifiex: fix memory leak associated with IE manamgement
ath9k: fix panic caused by returning a descriptor we have queued for reuse
mac80211: correct behaviour on unrecognised action frames
ath9k: enable serialize_regmode for non-PCIE AR9287
rtlwifi: rtl8192cu: New USB IDs
NFC: Return from rawsock_release when sk is NULL
iwlwifi: fix activating inactive stations
wlcore: drop INET dependency
ath9k: fix dynamic WEP related regression
NFC: Prevent multiple buffer overflows in NCI
netfilter: update location of my trees
...
Pull block bits from Jens Axboe:
"As vacation is coming up, thought I'd better get rid of my pending
changes in my for-linus branch for this iteration. It contains:
- Two patches for mtip32xx. Killing a non-compliant sysfs interface
and moving it to debugfs, where it belongs.
- A few patches from Asias. Two legit bug fixes, and one killing an
interface that is no longer in use.
- A patch from Jan, making the annoying partition ioctl warning a bit
less annoying, by restricting it to !CAP_SYS_RAWIO only.
- Three bug fixes for drbd from Lars Ellenberg.
- A fix for an old regression for umem, it hasn't really worked since
the plugging scheme was changed in 3.0.
- A few fixes from Tejun.
- A splice fix from Eric Dumazet, fixing an issue with pipe
resizing."
* 'for-linus' of git://git.kernel.dk/linux-block:
scsi: Silence unnecessary warnings about ioctl to partition
block: Drop dead function blk_abort_queue()
block: Mitigate lock unbalance caused by lock switching
block: Avoid missed wakeup in request waitqueue
umem: fix up unplugging
splice: fix racy pipe->buffers uses
drbd: fix null pointer dereference with on-congestion policy when diskless
drbd: fix list corruption by failing but already aborted reads
drbd: fix access of unallocated pages and kernel panic
xen/blkfront: Add WARN to deal with misbehaving backends.
blkcg: drop local variable @q from blkg_destroy()
mtip32xx: Create debugfs entries for troubleshooting
mtip32xx: Remove 'registers' and 'flags' from sysfs
blkcg: fix blkg_alloc() failure path
block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED
block: fix return value on cfq_init() failure
mtip32xx: Remove version.h header file inclusion
xen/blkback: Copy id field when doing BLKIF_DISCARD.
This patch adds the support for the Energy-Efficient Ethernet (EEE)
to the Physical Abstraction Layer.
To support the EEE we have to access to the MMD registers 3.20 and
7.60/61. So two new functions have been added to read/write the MMD
registers (clause 45).
An Ethernet driver (I tested the stmmac) can invoke the phy_init_eee to properly
check if the EEE is supported by the PHYs and it can also set the clock
stop enable bit in the 3.0 register.
The phy_get_eee_err can be used for reporting the number of time where
the PHY failed to complete its normal wake sequence.
In the end, this patch also adds the EEE ethtool support implementing:
o phy_ethtool_set_eee
o phy_ethtool_get_eee
v1: initial patch
v2: fixed some errors especially on naming convention
v3: renamed again the mmd read/write functions thank to Ben's feedback
v4: moved file to phy.c and added the ethtool support.
v5: fixed phy_adv_to_eee, phy_eee_to_supported, phy_eee_to_adv return
values according to ethtool API (thanks to Ben's feedback).
Renamed some macros to avoid too long names.
v6: fixed kernel-doc comments to be properly parsed.
Fixed the phy_init_eee function: we need to check which link mode
was autonegotiated and then the corresponding bits in 7.60 and 7.61
registers.
v7: reviewed the way to get the negotiated settings.
v8: fixed a problem in the phy_init_eee return value erroneously added
when included the phy_read_status call.
v9: do not remove the MDIO_AN_EEE_ADV_100TX and MDIO_AN_EEE_ADV_1000T
and fixed the eee_{cap,lp,adv} declaration as "int" instead of u16.
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It was noticed recently that when we send data on a transport, its possible that
we might bundle a sack that arrived on a different transport. While this isn't
a major problem, it does go against the SHOULD requirement in section 6.4 of RFC
2960:
An endpoint SHOULD transmit reply chunks (e.g., SACK, HEARTBEAT ACK,
etc.) to the same destination transport address from which it
received the DATA or control chunk to which it is replying. This
rule should also be followed if the endpoint is bundling DATA chunks
together with the reply chunk.
This patch seeks to correct that. It restricts the bundling of sack operations
to only those transports which have moved the ctsn of the association forward
since the last sack. By doing this we guarantee that we only bundle outbound
saks on a transport that has received a chunk since the last sack. This brings
us into stricter compliance with the RFC.
Vlad had initially suggested that we strictly allow only sack bundling on the
transport that last moved the ctsn forward. While this makes sense, I was
concerned that doing so prevented us from bundling in the case where we had
received chunks that moved the ctsn on multiple transports. In those cases, the
RFC allows us to select any of the transports having received chunks to bundle
the sack on. so I've modified the approach to allow for that, by adding a state
variable to each transport that tracks weather it has moved the ctsn since the
last sack. This I think keeps our behavior (and performance), close enough to
our current profile that I think we can do this without a sysctl knob to
enable/disable it.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yaseivch <vyasevich@gmail.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-sctp@vger.kernel.org
Reported-by: Michele Baldessari <michele@redhat.com>
Reported-by: sorin serban <sserban@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix kernel-doc warning. This struct member was removed in commit
875682648b ("irq: Remove irq_chip->release()") so remove its
associated kernel-doc entry also.
Warning(include/linux/irq.h:338): Excess struct/union/enum/typedef member 'release' description in 'irq_chip'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce IFF_LIVE_ADDR_CHANGE priv_flag and use it to disable
netif_running() check in eth_mac_addr()
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a hook in the binding path of netlink.
This is used by ctnetlink to allow module autoloading for the case
in which one user executes:
conntrack -E
So far, this resulted in nfnetlink loaded, but not
nf_conntrack_netlink.
I have received in the past many complains on this behaviour.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the following structure:
struct netlink_kernel_cfg {
unsigned int groups;
void (*input)(struct sk_buff *skb);
struct mutex *cb_mutex;
};
That can be passed to netlink_kernel_create to set optional configurations
for netlink kernel sockets.
I've populated this structure by looking for NULL and zero parameters at the
existing code. The remaining parameters that always need to be set are still
left in the original interface.
That includes optional parameters for the netlink socket creation. This allows
easy extensibility of this interface in the future.
This patch also adapts all callers to use this new interface.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
If rpfilter is off (or the SKB has an IPSEC path) and there are not
tclassid users, we don't have to do anything at all when
fib_validate_source() is invoked besides setting the itag to zero.
We monitor tclassid uses with a counter (modified only under RTNL and
marked __read_mostly) and we protect the fib_validate_source() real
work with a test against this counter and whether rpfilter is to be
done.
Having a way to know whether we need no tclassid processing or not
also opens the door for future optimized rpfilter algorithms that do
not perform full FIB lookups.
Signed-off-by: David S. Miller <davem@davemloft.net>
At Facebook, we do Layer-3 DSR via IP-in-IP tunneling. Our load balancers wrap
an extra IP header on incoming packets so they can be routed to the backend.
In the v4 tunnel driver, when these packets fall on the default tunl0 device,
the behavior is to decapsulate them and drop them back on the stack. So our
setup is that tunl0 has the VIP and eth0 has (obviously) the backend's real
address.
In IPv6 we do the same thing, but the v6 tunnel driver didn't have this same
behavior - if you didn't have an explicit tunnel setup, it would drop the
packet.
This patch brings that v4 feature to the v6 driver.
The same IPv6 address checks are performed as with any normal tunnel,
but as the fallback tunnel endpoint addresses are unspecified, the checks
must be performed on a per-packet basis, rather than at tunnel
configuration time.
[Patch description modified by phil@ipom.com]
Signed-off-by: Ville Nuorvala <ville.nuorvala@gmail.com>
Tested-by: Phil Dibowitz <phil@ipom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Checking for in_dev being NULL is pointless.
In fact, all of our callers have in_dev precomputed already,
so just pass it in and remove the NULL checking.
Signed-off-by: David S. Miller <davem@davemloft.net>
Using NLMSG_GOODSIZE results in multiple pages being used as
nlmsg_new() will automatically add the size of the netlink
header to the payload thus exceeding the page limit.
NLMSG_DEFAULT_SIZE takes this into account.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Cc: Jiri Pirko <jpirko@redhat.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Reviewed-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit changes inet_csk_route_req() so that it uses a pointer to
a struct flowi6, rather than allocating its own on the stack. This
brings its behavior in line with its IPv4 cousin,
inet_csk_route_req(), and allows a follow-on patch to fix a dst leak.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/caif/caif_hsi.c
drivers/net/usb/qmi_wwan.c
The qmi_wwan merge was trivial.
The caif_hsi.c, on the other hand, was not. It's a conflict between
1c385f1fdf ("caif-hsi: Replace platform
device with ops structure.") in the net-next tree and commit
39abbaef19 ("caif-hsi: Postpone init of
HIS until open()") in the net tree.
I did my best with that one and will ask Sjur to check it out.
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking update from David Miller:
1) Pairing and deadlock fixes in bluetooth from Johan Hedberg.
2) Add device IDs for AR3011 and AR3012 bluetooth chips. From
Giancarlo Formicuccia and Marek Vasut.
3) Fix wireless regulatory deadlock, from Eliad Peller.
4) Fix full TX ring panic in bnx2x driver, from Eric Dumazet.
5) Revert the two commits that added skb_orphan_try(), it causes
erratic bonding behavior with UDP clients and the gains it used to
give are mostly no longer happening due to how BQL works. From Eric
Dumazet.
6) It took two tries, but Thomas Graf fixed a problem wherein we
registered ipv6 routing procfs files before their backend data were
initialized properly.
7) Fix max GSO size setting in be2net, from Sarveshwar Bandi.
8) PHY device id mask is wrong for KSZ9021 and KS8001 chips, fix from
Jason Wang.
9) Fix use of stale SKB data pointer after skb_linearize() call in
batman-adv, from Antonio Quartulli.
10) Fix memory leak in IXGBE due to missing __GFP_COMP, from Alexander
Duyck.
11) Fix probing of Gobi devices in qmi_wwan usbnet driver, from Bjørn
Mork.
12) Fix suspend/resume and open failure handling in usbnet from Ming
Lei.
13) Attempt to fix device r8169 hangs for certain chips, from Francois
Romieu.
14) Fix advancement of RX dirty pointer in some situations in sh_eth
driver, from Yoshihiro Shimoda.
15) Attempt to fix restart of IPV6 routing table dumps when there is an
intervening table update. From Eric Dumazet.
16) Respect security_inet_conn_request() return value in ipv6 TCP. From
Neal Cardwell.
17) Add another iPAD device ID to ipheth driver, from Davide Gerhard.
18) Fix access to freed SKB in l2tp_eth_dev_xmit(), and fix l2tp lockdep
splats, from Eric Dumazet.
19) Make sure all bridge devices, regardless of whether they were
created via netlink or ioctls, have their rtnetlink ops hooked up.
From Thomas Graf and Stephen Hemminger.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (81 commits)
9p: fix min_t() casting in p9pdu_vwritef()
can: flexcan: use be32_to_cpup to handle the value of dt entry
xen/netfront: teardown the device before unregistering it.
bridge: Assign rtnl_link_ops to bridge devices created via ioctl (v2)
vhost: use USER_DS in vhost_worker thread
ixgbe: Do not pad FCoE frames as this can cause issues with FCoE DDP
net: l2tp_eth: use LLTX to avoid LOCKDEP splats
mac802154: add missed braces
net: l2tp_eth: fix l2tp_eth_dev_xmit race
net/mlx4_en: Release QP range in free_resources
net/mlx4: Use single completion vector after NOP failure
net/mlx4_en: Set correct port parameters during device initialization
ipheth: add support for iPad
caif-hsi: Add missing return in error path
caif-hsi: Bugfix - Piggyback'ed embedded CAIF frame lost
caif: Clear shutdown mask to zero at reconnect.
tcp: heed result of security_inet_conn_request() in tcp_v6_conn_request()
ipv6: fib: fix fib dump restart
batman-adv: fix race condition in TT full-table replacement
batman-adv: only drop packets of known wifi clients
...
The specific destination is the host we direct unicast replies to.
Usually this is the original packet source address, but if we are
responding to a multicast or broadcast packet we have to use something
different.
Specifically we must use the source address we would use if we were to
send a packet to the unicast source of the original packet.
The routing cache precomputes this value, but we want to remove that
precomputation because it creates a hard dependency on the expensive
rpfilter source address validation which we'd like to make cheaper.
There are only three places where this matters:
1) ICMP replies.
2) pktinfo CMSG
3) IP options
Now there will be no real users of rt->rt_spec_dst and we can simply
remove it altogether.
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename it to ip_send_unicast_reply() and add explicit 'saddr'
argument.
This removed one of the few users of rt->rt_spec_dst.
Signed-off-by: David S. Miller <davem@davemloft.net>
