Each nexthop is added like a single route in the routing table. All routes
that have the same metric/weight and destination but not the same gateway
are considering as ECMP routes. They are linked together, through a list called
rt6i_siblings.

ECMP routes can be added in one shot, with RTA_MULTIPATH attribute or one after
the other (in both case, the flag NLM_F_EXCL should not be set).

The patch is based on a previous work from
Luc Saillard <luc.saillard@6wind.com>.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib6_add_1() should consistently return errno pointers,
rather than a mixture of NULL and errno pointers.
Signed-off-by: NLin Ming <mlin@ss.pku.edu.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of error, the function fib6_add_1() returns ERR_PTR()
or NULL pointer. The ERR_PTR() case check is missing in fib6_add().

dpatch engine is used to generated this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 2bec5a36 (ipv6: fib: fix crash when changing large fib
while dumping it) introduced ability to restart the dump at tree root,
but failed to skip correctly a count of already dumped entries. Code
didn't match Patrick intent.

We must skip exactly the number of already dumped entries.

Note that like other /proc/net files or netlink producers, we could
still dump some duplicates entries.
Reported-by: NDebabrata Banerjee <dbavatar@gmail.com>
Reported-by: NJosh Hunt <johunt@akamai.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 2a0c451a.

It causes crashes, because now ip6_null_entry is used before
it is initialized.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

/proc/net/ipv6_route reflects the contents of fib_table_hash. The proc
handler is installed in ip6_route_net_init() whereas fib_table_hash is
allocated in fib6_net_init() _after_ the proc handler has been installed.

This opens up a short time frame to access fib_table_hash with its pants
down.

fib6_init() as a whole can't be moved to an earlier position as it also
registers the rtnetlink message handlers which should be registered at
the end. Therefore split it into fib6_init() which is run early and
fib6_init_late() to register the rtnetlink message handlers.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Reviewed-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 5339ab8b (ipv6: fib: Convert fib6_age() to
dst_neigh_lookup().) seems to have mistakenly inverted the
exception for cached NTF_ROUTER routes.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the current debugging style and enable dynamic_debug.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add #define pr_fmt(fmt) as appropriate.

Add "IPv6: " to appropriate files.

Convert printk(KERN_<LEVEL> to pr_<level> (but not KERN_DEBUG).
Standardize on "%s: " not "%s(): " when emitting __func__.
Use "%s: ", __func__ instead of embedding function name.
Coalesce formats, align arguments.

ADDRCONF output is now prefixed with "IPv6: "
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the ipv6 dst cache which copy from the dst generated by ICMPV6 RA packet.
this dst cache will not check expire because it has no RTF_EXPIRES flag.
So this dst cache will always be used until the dst gc run.

Change the struct dst_entry,add a union contains new pointer from and expires.
When rt6_info.rt6i_flags has no RTF_EXPIRES flag,the dst.expires has no use.
we can use this field to point to where the dst cache copy from.
The dst.from is only used in IPV6.

rt6_check_expired check if rt6_info.dst.from is expired.

ip6_rt_copy only set dst.from when the ort has flag RTF_ADDRCONF
and RTF_DEFAULT.then hold the ort.

ip6_dst_destroy release the ort.

Add some functions to operate the RTF_EXPIRES flag and expires(from) together.
and change the code to use these new adding functions.

Changes from v5:
modify ip6_route_add and ndisc_router_discovery to use new adding functions.

Only set dst.from when the ort has flag RTF_ADDRCONF
and RTF_DEFAULT.then hold the ort.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In this specific situation we know we are dealing with a gatewayed route
and therefore rt6i_gateway is not going to be in6addr_any even in future
interpretations.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

During some debugging I needed to look into how /proc/net/ipv6_route
operated and in my digging I found its calling fib6_clean_all() which uses
"write_lock_bh(&table->tb6_lock)" before doing the walk of the table. I
found this on 2.6.32, but reading the code I believe the same basic idea
exists currently. Looking at the rtnetlink code they are only calling
"read_lock_bh(&table->tb6_lock);" via fib6_dump_table(). While I realize
reading from proc isn't the recommended way of fetching the ipv6 route
table; taking a write lock seems unnecessary and would probably cause
network performance issues.

To verify this I loaded up the ipv6 route table and then ran iperf in 3
cases:
  * doing nothing
  * reading ipv6 route table via proc
    (while :; do cat /proc/net/ipv6_route > /dev/null; done)
  * reading ipv6 route table via rtnetlink
    (while :; do ip -6 route show table all > /dev/null; done)

* Load the ipv6 route table up with:
  * for ((i = 0;i < 4000;i++)); do ip route add unreachable 2000::$i; done

* iperf commands:
  * client: iperf -i 1 -V -c <ipv6 addr>
  * server: iperf -V -s

* iperf results - 3 runs each (in Mbits/sec)
  * nothing: client: 927,927,927 server: 927,927,927
  * proc: client: 179,97,96,113 server: 142,112,133
  * iproute: client: 928,927,928 server: 927,927,927

lock_stat shows taking the write lock is causing the slowdown. Using this
info I decided to write a version of fib6_clean_all() which replaces
write_lock_bh(&table->tb6_lock) with read_lock_bh(&table->tb6_lock). With
this new function I see the same results as with my rtnetlink iperf test.
Signed-off-by: NJosh Hunt <joshhunt00@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It just obscures that the netdevice pointer and the expires value are
implemented in the dst_entry sub-object of the ipv6 route.

And it makes grepping for dst_entry member uses much harder too.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To reflect the fact that a refrence is not obtained to the
resulting neighbour entry.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NRoland Dreier <roland@purestorage.com>

1) x == NULL --> !x
2) x != NULL --> x
3) if() --> if ()
4) while() --> while ()
5) (x & BIT) == 0 --> !(x & BIT)
6) (x&BIT) --> (x & BIT)
7) x=y --> x = y
8) (BIT1|BIT2) --> (BIT1 | BIT2)
9) if ((x & BIT)) --> if (x & BIT)
10) proper argument and struct member alignment
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a crash when non existing IPv6 route is tried to be changed.

When new destination node was inserted in middle of FIB6 tree, no relevant
sanity checks were performed. Later route insertion might have been prevented
due to invalid request, causing node with no rt info being left in tree.
When this node was accessed, a crash occurred.

Patch adds missing checks in fib6_add_1()
Signed-off-by: NMatti Vaittinen <Mazziesaccount@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch removes unnecessary NULL checks noticed by Dan Carpenter.
Checks were introduced in commit
4a287eba to net-next.
Signed-off-by: NMatti Vaittinen <Mazziesaccount@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The support for NLM_F_* flags at IPv6 routing requests.

If NLM_F_CREATE flag is not defined for RTM_NEWROUTE request,
warning is printed, but no error is returned. Instead new route is
added. Later NLM_F_CREATE may be required for
new route creation.

Exception is when NLM_F_REPLACE flag is given without NLM_F_CREATE, and
no matching route is found. In this case it should be safe to assume
that the request issuer is familiar with NLM_F_* flags, and does really
not want route to be created.

Specifying NLM_F_REPLACE flag will now make the kernel to search for
matching route, and replace it with new one. If no route is found and
NLM_F_CREATE is specified as well, then new route is created.

Also, specifying NLM_F_EXCL will yield returning of error if matching
route is found.

Patch created against linux-3.2-rc1
Signed-off-by: NMatti Vaittinen <Mazziesaccount@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This cleanup patch removes unnecessary include from net/ipv6/ip6_fib.c.
Signed-off-by: NKevin Wilson <wkevils@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Gergely Kalman reported crashes in check_peer_redir().

It appears commit f39925db (ipv4: Cache learned redirect
information in inetpeer.) added a race, leading to possible NULL ptr
dereference.

Since we can now change dst neighbour, we should make sure a reader can
safely use a neighbour.

Add RCU protection to dst neighbour, and make sure check_peer_redir()
can be called safely by different cpus in parallel.

As neighbours are already freed after one RCU grace period, this patch
should not add typical RCU penalty (cache cold effects)

Many thanks to Gergely for providing a pretty report pointing to the
bug.
Reported-by: NGergely Kalman <synapse@hippy.csoma.elte.hu>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dst_{get,set}_neighbour()
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It just makes it harder to see 1) what the code is doing
and 2) grep for all users of dst{->,.}neighbour
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The message size allocated for rtnl ifinfo dumps was limited to
a single page.  This is not enough for additional interface info
available with devices that support SR-IOV and caused a bug in
which VF info would not be displayed if more than approximately
40 VFs were created per interface.

Implement a new function pointer for the rtnl_register service that will
calculate the amount of data required for the ifinfo dump and allocate
enough data to satisfy the request.
Signed-off-by: NGreg Rose <gregory.v.rose@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Four years ago, Patrick made a change to hold rtnl mutex during netlink
dump callbacks.

I believe it was a wrong move. This slows down concurrent dumps, making
good old /proc/net/ files faster than rtnetlink in some situations.

This occurred to me because one "ip link show dev ..." was _very_ slow
on a workload adding/removing network devices in background.

All dump callbacks are able to use RCU locking now, so this patch does
roughly a revert of commits :

1c2d670f : [RTNETLINK]: Hold rtnl_mutex during netlink dump callbacks
6313c1e0 : [RTNETLINK]: Remove unnecessary locking in dump callbacks

This let writers fight for rtnl mutex and readers going full speed.

It also takes care of phonet : phonet_route_get() is now called from rcu
read section. I renamed it to phonet_route_get_rcu()
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add const qualifiers to structs iphdr, ipv6hdr and in6_addr pointers
where possible, to make code intention more obvious.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While doing profile analysis, I found fib_hash_table was sometime in a
cache line shared by a possibly often written kernel structure.

(CONFIG_IP_ROUTE_MULTIPATH || !CONFIG_IPV6_MULTIPLE_TABLES)

It's hard to detect because not easily reproductible.

Make sure we allocate a full cache line to keep this shared in all cpus
caches.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

remove useless union keyword in rtable, rt6_info and dn_route.

Since there is only one member in a union, the union keyword isn't useful.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sparse can help us find endianness bugs, but we need to make some
cleanups to be able to more easily spot real bugs.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

addr_bit_test() is used in various places in IPv6 routing table
subsystem.  It checks if the given fn_bit is set,
where fn_bit counts bits from MSB in words in network-order.

 fn_bit        :   0 .... 31 32 .... 64 65 .... 95 96 ....127

fn_bit >> 5 gives offset of word, and (~fn_bit & 0x1f) gives
count from LSB in the network-endian word in question.

 fn_bit >> 5   :       0          1          2          3
 ~fn_bit & 0x1f:  31 ....  0 31 ....  0 31 ....  0 31 ....  0

Thus, the mask was generated as htonl(1 << (~fn_bit & 0x1f)).
This can be optimized by "sweezle" (See include/asm-generic/bitops/le.h).

In little-endian,
  htonl(1 << bit) = 1 << (bit ^ BITOP_BE32_SWIZZLE)
where
  BITOP_BE32_SWIZZLE is (0x1f & ~7)
So,
  htonl(1 << (~fn_bit & 0x1f)) = 1 << ((~fn_bit & 0x1f) ^ (0x1f & ~7))
                               = 1 << ((~fn_bit ^ ~7) & 0x1f)
                               = 1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)

In big-endian, BITOP_BE32_SWIZZLE is equal to 0.
  1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
                               = 1 << ((~fn_bit) & 0x1f)
                               = htonl(1 << (~fn_bit & 0x1f))
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the fib size exceeds what can be dumped in a single skb, the
dump is suspended and resumed once the last skb has been received
by userspace. When the fib is changed while the dump is suspended,
the walker might contain stale pointers, causing a crash when the
dump is resumed.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
IP: [<ffffffffa01bce04>] fib6_walk_continue+0xbb/0x124 [ipv6]
PGD 5347a067 PUD 65c7067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
...
RIP: 0010:[<ffffffffa01bce04>]
[<ffffffffa01bce04>] fib6_walk_continue+0xbb/0x124 [ipv6]
...
Call Trace:
 [<ffffffff8104aca3>] ? mutex_spin_on_owner+0x59/0x71
 [<ffffffffa01bd105>] inet6_dump_fib+0x11b/0x1b9 [ipv6]
 [<ffffffff81371af4>] netlink_dump+0x5b/0x19e
 [<ffffffff8134f288>] ? consume_skb+0x28/0x2a
 [<ffffffff81373b69>] netlink_recvmsg+0x1ab/0x2c6
 [<ffffffff81372781>] ? netlink_unicast+0xfa/0x151
 [<ffffffff813483e0>] __sock_recvmsg+0x6d/0x79
 [<ffffffff81348a53>] sock_recvmsg+0xca/0xe3
 [<ffffffff81066d4b>] ? autoremove_wake_function+0x0/0x38
 [<ffffffff811ed1f8>] ? radix_tree_lookup_slot+0xe/0x10
 [<ffffffff810b3ed7>] ? find_get_page+0x90/0xa5
 [<ffffffff810b5dc5>] ? filemap_fault+0x201/0x34f
 [<ffffffff810ef152>] ? fget_light+0x2f/0xac
 [<ffffffff813519e7>] ? verify_iovec+0x4f/0x94
 [<ffffffff81349a65>] sys_recvmsg+0x14d/0x223

Store the serial number when beginning to walk the fib and reload
pointers when continuing to walk after a change occured. Similar
to other dumping functions, this might cause unrelated entries to
be missed when entries are deleted.
Tested-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

__net_init/__net_exit are apparently not going away, so use them
to full extent.

In some cases __net_init was removed, because it was called from
__net_exit code.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Choose saner defaults for xfrm[4|6] gc_thresh values on init

Currently, the xfrm[4|6] code has hard-coded initial gc_thresh values
(set to 1024).  Given that the ipv4 and ipv6 routing caches are sized
dynamically at boot time, the static selections can be non-sensical.
This patch dynamically selects an appropriate gc threshold based on
the corresponding main routing table size, using the assumption that
we should in the worst case be able to handle as many connections as
the routing table can.

For ipv4, the maximum route cache size is 16 * the number of hash
buckets in the route cache.  Given that xfrm4 starts garbage
collection at the gc_thresh and prevents new allocations at 2 *
gc_thresh, we set gc_thresh to half the maximum route cache size.

For ipv6, its a bit trickier.  there is no maximum route cache size,
but the ipv6 dst_ops gc_thresh is statically set to 1024.  It seems
sane to select a simmilar gc_thresh for the xfrm6 code that is half
the number of hash buckets in the v6 route cache times 16 (like the v4
code does).
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a fib6 table dump is prematurely ended, we won't unlink
its walker from the list.  This causes all sorts of grief for
other users of the list later.
Reported-by: NChris Caputo <ccaputo@alt.net>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ipv6_dev_get_saddr() blindly de-references dst_dev to get the network
namespace, but some callers might pass NULL.  Change callers to pass a
namespace pointer instead.
Signed-off-by: NBrian Haley <brian.haley@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.

I could make at least one BUILD_BUG_ON conversion.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>