When route caching is disabled (rt_caching returns false), We still use route
cache entries that are created and passed into rt_intern_hash once. These
routes need to be made usable for the one call path that holds a reference to
them, and they need to be reclaimed when they're finished with their use. To be
made usable, they need to be associated with a neighbor table entry (which they
currently are not), otherwise iproute_finish2 just discards the packet, since we
don't know which L2 peer to send the packet to. To do this binding, we need to
follow the path a bit higher up in rt_intern_hash, which calls
arp_bind_neighbour, but not assign the route entry to the hash table.
Currently, if caching is off, we simply assign the route to the rp pointer and
are reutrn success. This patch associates us with a neighbor entry first.
Secondly, we need to make sure that any single use routes like this are known to
the garbage collector when caching is off. If caching is off, and we try to
hash in a route, it will leak when its refcount reaches zero. To avoid this,
this patch calls rt_free on the route cache entry passed into rt_intern_hash.
This places us on the gc list for the route cache garbage collector, so that
when its refcount reaches zero, it will be reclaimed (Thanks to Alexey for this
suggestion).
I've tested this on a local system here, and with these patches in place, I'm
able to maintain routed connectivity to remote systems, even if I set
/proc/sys/net/ipv4/rt_cache_rebuild_count to -1, which forces rt_caching to
return false.
Signed-off-by: Neil Horman <nhorman@redhat.com>
Reported-by: Jarek Poplawski <jarkao2@gmail.com>
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't drop route if we're not caching
I recently got a report of an oops on a route lookup. Maxime was
testing what would happen if route caching was turned off (doing so by setting
making rt_caching always return 0), and found that it triggered an oops. I
looked at it and found that the problem stemmed from the fact that the route
lookup routines were returning success from their lookup paths (which is good),
but never set the **rp pointer to anything (which is bad). This happens because
in rt_intern_hash, if rt_caching returns false, we call rt_drop and return 0.
This almost emulates slient success. What we should be doing is assigning *rp =
rt and _not_ dropping the route. This way, during slow path lookups, when we
create a new route cache entry, we don't immediately discard it, rather we just
don't add it into the cache hash table, but we let this one lookup use it for
the purpose of this route request. Maxime has tested and reports it prevents
the oops. There is still a subsequent routing issue that I'm looking into
further, but I'm confident that, even if its related to this same path, this
patch makes sense to take.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the sake of power saver lovers, use a deferrable timer to fire
rt_check_expire()
As some big routers cache equilibrium depends on garbage collection
done in time, we take into account elapsed time between two
rt_check_expire() invocations to adjust the amount of slots we have to
check.
Based on an initial idea and patch from Tero Kristo
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define three accessors to get/set dst attached to a skb
struct dst_entry *skb_dst(const struct sk_buff *skb)
void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;
Delete skb->dst field
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define skb_rtable(const struct sk_buff *skb) accessor to get rtable from skb
Delete skb->rtable field
Setting rtable is not allowed, just set dst instead as rtable is an alias.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexander V. Lukyanov found a regression in 2.6.29 and made a complete
analysis found in http://bugzilla.kernel.org/show_bug.cgi?id=13339
Quoted here because its a perfect one :
begin_of_quotation
2.6.29 patch has introduced flexible route cache rebuilding. Unfortunately the
patch has at least one critical flaw, and another problem.
rt_intern_hash calculates rthi pointer, which is later used for new entry
insertion. The same loop calculates cand pointer which is used to clean the
list. If the pointers are the same, rtable leak occurs, as first the cand is
removed then the new entry is appended to it.
This leak leads to unregister_netdevice problem (usage count > 0).
Another problem of the patch is that it tries to insert the entries in certain
order, to facilitate counting of entries distinct by all but QoS parameters.
Unfortunately, referencing an existing rtable entry moves it to list beginning,
to speed up further lookups, so the carefully built order is destroyed.
For the first problem the simplest patch it to set rthi=0 when rthi==cand, but
it will also destroy the ordering.
end_of_quotation
Problematic commit is 1080d709fb
(net: implement emergency route cache rebulds when gc_elasticity is exceeded)
Trying to keep dst_entries ordered is too complex and breaks the fact that
order should depend on the frequency of use for garbage collection.
A possible fix is to make rt_intern_hash() simpler, and only makes
rt_check_expire() a litle bit smarter, being able to cope with an arbitrary
entries order. The added loop is running on cache hot data, while cpu
is prefetching next object, so should be unnoticied.
Reported-and-analyzed-by: Alexander V. Lukyanov <lav@yar.ru>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rt_check_expire() computes average and standard deviation of chain lengths,
but not correclty reset length to 0 at beginning of each chain.
This probably gives overflows for sum2 (and sum) on loaded machines instead
of meaningful results.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now we have no upper limit on the size of the route cache hash table.
On a 128GB POWER6 box it ends up as 32MB:
IP route cache hash table entries: 4194304 (order: 9, 33554432 bytes)
It would be nice to cap this for memory consumption reasons, but a massive
hashtable also causes a significant spike when measuring OS jitter.
With a 32MB hashtable and 4 million entries, rt_worker_func is taking
5 ms to complete. On another system with more memory it's taking 14 ms.
Even though rt_worker_func does call cond_sched() to limit its impact,
in an HPC environment we want to keep all sources of OS jitter to a minimum.
With the patch applied we limit the number of entries to 512k which
can still be overriden by using the rt_entries boot option:
IP route cache hash table entries: 524288 (order: 6, 4194304 bytes)
With this patch rt_worker_func now takes 0.460 ms on the same system.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Impact: build fix
API was changed, but not all usage sites were converted:
net/ipv4/route.c: In function ‘ip_rt_init’:
net/ipv4/route.c:3379: error: too few arguments to function ‘__alloc_percpu’
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Base versions handle constant folding now.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This last patch makes the appropriate changes to use and propagate the
network namespace where needed in IPv4 multicast routing code.
This consists mainly in replacing all the remaining init_net occurences
with current netns pointer retrieved from sockets, net devices or
mfc_caches depending on the routines' contexts.
Some routines receive a new 'struct net' parameter to propagate the current
netns:
* vif_add/vif_delete
* ipmr_new_tunnel
* mroute_clean_tables
* ipmr_cache_find
* ipmr_cache_report
* ipmr_cache_unresolved
* ipmr_mfc_add/ipmr_mfc_delete
* ipmr_get_route
* rt_fill_info (in route.c)
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In future all cpumask ops will only be valid (in general) for bit
numbers < nr_cpu_ids. So use that instead of NR_CPUS in iterators
and other comparisons.
This is always safe: no cpu number can be >= nr_cpu_ids, and
nr_cpu_ids is initialized to NR_CPUS at boot.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass netns to xfrm_lookup()/__xfrm_lookup(). For that pass netns
to flow_cache_lookup() and resolver callback.
Take it from socket or netdevice. Stub DECnet to init_net.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I want to compile out proc_* and sysctl_* handlers totally and
stub them to NULL depending on config options, however usage of &
will prevent this, since taking adress of NULL pointer will break
compilation.
So, drop & in front of every ->proc_handler and every ->strategy
handler, it was never needed in fact.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u
can be replaced with %pI4
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
call_rcu() will unconditionally rewrite RCU head anyway.
Applies to
struct neigh_parms
struct neigh_table
struct net
struct cipso_v4_doi
struct in_ifaddr
struct in_device
rt->u.dst
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a patch to provide on demand route cache rebuilding. Currently, our
route cache is rebulid periodically regardless of need. This introduced
unneeded periodic latency. This patch offers a better approach. Using code
provided by Eric Dumazet, we compute the standard deviation of the average hash
bucket chain length while running rt_check_expire. Should any given chain
length grow to larger that average plus 4 standard deviations, we trigger an
emergency hash table rebuild for that net namespace. This allows for the common
case in which chains are well behaved and do not grow unevenly to not incur any
latency at all, while those systems (which may be being maliciously attacked),
only rebuild when the attack is detected. This patch take 2 other factors into
account:
1) chains with multiple entries that differ by attributes that do not affect the
hash value are only counted once, so as not to unduly bias system to rebuilding
if features like QOS are heavily used
2) if rebuilding crosses a certain threshold (which is adjustable via the added
sysctl in this patch), route caching is disabled entirely for that net
namespace, since constant rebuilding is less efficient that no caching at all
Tested successfully by me.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
net: Remove CONFIG_KMOD from net/ (towards removing CONFIG_KMOD entirely)
ipv4: Add a missing rcu_assign_pointer() in routing cache.
[netdrvr] ibmtr: PCMCIA IBMTR is ok on 64bit
xen-netfront: Avoid unaligned accesses to IP header
lmc: copy_*_user under spinlock
[netdrvr] myri10ge, ixgbe: remove broken select INTEL_IOATDMA
rt_intern_hash() is doing an update of a RCU guarded hash chain
without using rcu_assign_pointer() or equivalent barrier.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
name and nlen parameters passed to ->strategy hook are unused, remove
them. In general ->strategy hook should know what it's doing, and don't
do something tricky for which, say, pointer to original userspace array
may be needed (name).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net> [ networking bits ]
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ip_route_output() contains a check to make sure that no flows with
non-local source IP addresses are routed. This obviously makes using
such addresses impossible.
This patch introduces a flowi flag which makes omitting this check
possible. The new flag provides a way of handling transparent and
non-transparent connections differently.
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
When scanning route cache hash table, we can avoid taking locks for
empty buckets. Both /proc/net/rt_cache and NETLINK RTM_GETROUTE
interface are taken into account.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net.ipv4.neigh should be a part of skeleton to avoid ordering problems
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let me first state that disabling the route cache hash rebuild
should not be done without extensive analysis on the risk profile
and careful deliberation.
However, there are times when this can be done safely or for
testing. For example, when you have mechanisms for ensuring
that offending parties do not exist in your network.
This patch lets the user disable the rebuild if the interval is
set to zero. This also incidentally fixes a divide-by-zero error
with name-spaces.
In addition, this patch makes the effect of an interval change
immediate rather than it taking effect at the next rebuild as
is currently the case.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch replaces dst_metric() with dst_mtu() in net/ipv4/route.c.
Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (46 commits)
tcp: MD5: Fix IPv6 signatures
skbuff: add missing kernel-doc for do_not_encrypt
net/ipv4/route.c: fix build error
tcp: MD5: Fix MD5 signatures on certain ACK packets
ipv6: Fix ip6_xmit to send fragments if ipfragok is true
ipvs: Move userspace definitions to include/linux/ip_vs.h
netdev: Fix lockdep warnings in multiqueue configurations.
netfilter: xt_hashlimit: fix race between htable_destroy and htable_gc
netfilter: ipt_recent: fix race between recent_mt_destroy and proc manipulations
netfilter: nf_conntrack_tcp: decrease timeouts while data in unacknowledged
irda: replace __FUNCTION__ with __func__
nsc-ircc: default to dongle type 9 on IBM hardware
bluetooth: add quirks for a few hci_usb devices
hysdn: remove the packed attribute from PofTimStamp_tag
isdn: use the common ascii hex helpers
tg3: adapt tg3 to use reworked PCI PM code
atm: fix direct casts of pointers to u32 in the InterPhase driver
atm: fix const assignment/discard warnings in the ATM networking driver
net: use the common ascii hex helpers
random32: seeding improvement
...
fix:
net/ipv4/route.c: In function 'ip_static_sysctl_init':
net/ipv4/route.c:3225: error: 'ipv4_route_path' undeclared (first use in this function)
net/ipv4/route.c:3225: error: (Each undeclared identifier is reported only once
net/ipv4/route.c:3225: error: for each function it appears in.)
net/ipv4/route.c:3225: error: 'ipv4_route_table' undeclared (first use in this function)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Piss-poor sysctl registration API strikes again, film at 11...
What we really need is _pathname_ required to be present in already
registered table, so that kernel could warn about bad order. That's the
next target for sysctl stuff (and generally saner and more explicit
order of initialization of ipv[46] internals wouldn't hurt either).
For the time being, here are full fixups required by ..._rotable()
stuff; we make per-net sysctl sets descendents of "ro" one and make sure
that sufficient skeleton is there before we start registering per-net
sysctls.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Running recent kernels, and using a particular vpn gateway, I've been
having to edit my mails down to get them accepted by the smtp server.
Git bisect led to commit e84f84f276 -
netns: place rt_genid into struct net. The conversion from a != test
to rt_is_expired() put one negative too many: and now my mail works.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is possible to avoid locking at all in ipv4_sysctl_rtcache_flush by
defining local ctl_table on the stack.
The patch is based on the suggestion from Eric W. Biederman.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
dst cache is marked as expired on the per/namespace basis by previous
path. Right now we have to implement selective cache shrinking. This
procedure has been ported from older OpenVz codebase.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Basically, there is no difference to atomic_read internally or pass it as
a parameter as rt_hash is inline.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
flush delay is used as an external storage for net.ipv4.route.flush sysctl
entry. It is write-only.
The ctl_table->data for this entry is used once. Fix this case to point
to the stack to remove global variable. Do this to avoid additional
variable on struct net in the next patch.
Possible race (as it was before) accessing this local variable is removed
using flush_mutex.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes CVS keywords that weren't updated for a long time
from comments.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Also removes an obsolete check for the unused flag RTCF_MASQ.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Because the IPsec output function xfrm_output_resume does its
own dst_output call it should always call __ip_local_output
instead of ip_local_output as the latter may invoke dst_output
directly. Otherwise the return values from nf_hook and dst_output
may clash as they both use the value 1 but for different purposes.
When that clash occurs this can cause a packet to be used after
it has been freed which usually leads to a crash. Because the
offending value is only returned from dst_output with qdiscs
such as HTB, this bug is normally not visible.
Thanks to Marco Berizzi for his perseverance in tracking this
down.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are functions to refer to the value of dst->metric[THE_METRIC-1]
directly without use of a inline function "dst_metric" defined in
net/dst.h.
The following patch changes them to use the inline function
consistently.
Signed-off-by: Satoru SATOH <satoru.satoh@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Neil Horman