linux-stable.git/net/ipv6/ip6_fib.c, branch linux-3.3.y

IPv6: Avoid taking write lock for /proc/net/ipv6_route

2011-12-30T22:07:33+00:00

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 
  * 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: Josh Hunt 
Signed-off-by: David S. Miller

ipv6: Kill rt6i_dev and rt6i_expires defines.

2011-12-29T01:19:20+00:00

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: David S. Miller

net: Rename dst_get_neighbour{, _raw} to dst_get_neighbour_noref{, _raw}.

2011-12-05T20:20:19+00:00

To reflect the fact that a refrence is not obtained to the
resulting neighbour entry.

Signed-off-by: David S. Miller 
Acked-by: Roland Dreier

ipv6: Various cleanups in ip6_route.c

2011-12-03T22:50:45+00:00

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: David S. Miller

ipv6: Use pr_warn() in ip6_fib.c

2011-11-17T08:18:28+00:00

Signed-off-by: David S. Miller

IPV6 Fix a crash when trying to replace non existing route

2011-11-17T08:16:25+00:00

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: Matti Vaittinen 
Signed-off-by: David S. Miller

IPv6: Removing unnecessary NULL checks.

2011-11-15T21:54:20+00:00

This patch removes unnecessary NULL checks noticed by Dan Carpenter.
Checks were introduced in commit
4a287eba2de395713d8b2b2aeaa69fa086832d34 to net-next.

Signed-off-by: Matti Vaittinen 
Signed-off-by: David S. Miller

IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag

2011-11-14T19:35:33+00:00

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: Matti Vaittinen 
Signed-off-by: David S. Miller

cleanup: remove unnecessary include.

2011-10-19T23:26:16+00:00

This cleanup patch removes unnecessary include from net/ipv6/ip6_fib.c.

Signed-off-by: Kevin Wilson 
Signed-off-by: David S. Miller

net: fix NULL dereferences in check_peer_redir()

2011-08-03T10:34:12+00:00

Gergely Kalman reported crashes in check_peer_redir().

It appears commit f39925dbde778 (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: Gergely Kalman 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller