linux-stable.git/net/ipv4/inetpeer.c, branch linux-3.4.y

inetpeer: get rid of ip_id_count

2014-08-14T00:42:35+00:00

[ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ]

Ideally, we would need to generate IP ID using a per destination IP
generator.

linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.

1) each inet_peer struct consumes 192 bytes

2) inetpeer cache uses a binary tree of inet_peer structs,
   with a nominal size of ~66000 elements under load.

3) lookups in this tree are hitting a lot of cache lines, as tree depth
   is about 20.

4) If server deals with many tcp flows, we have a high probability of
   not finding the inet_peer, allocating a fresh one, inserting it in
   the tree with same initial ip_id_count, (cf secure_ip_id())

5) We garbage collect inet_peer aggressively.

IP ID generation do not have to be 'perfect'

Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.

We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.

ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)

secure_ip_id() and secure_ipv6_id() no longer are needed.

Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ip: generate unique IP identificator if local fragmentation is allowed

2013-10-13T22:42:48+00:00

[ Upstream commit 703133de331a7a7df47f31fb9de51dc6f68a9de8 ]

If local fragmentation is allowed, then ip_select_ident() and
ip_select_ident_more() need to generate unique IDs to ensure
correct defragmentation on the peer.

For example, if IPsec (tunnel mode) has to encrypt large skbs
that have local_df bit set, then all IP fragments that belonged
to different ESP datagrams would have used the same identificator.
If one of these IP fragments would get lost or reordered, then
peer could possibly stitch together wrong IP fragments that did
not belong to the same datagram. This would lead to a packet loss
or data corruption.

Signed-off-by: Ansis Atteka 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

inetpeer: fix a race in inetpeer_gc_worker()

2012-07-16T16:03:45+00:00

[ Upstream commit 55432d2b543a4b6dfae54f5c432a566877a85d90 ]

commit 5faa5df1fa2024 (inetpeer: Invalidate the inetpeer tree along with
the routing cache) added a race :

Before freeing an inetpeer, we must respect a RCU grace period, and make
sure no user will attempt to increase refcnt.

inetpeer_invalidate_tree() waits for a RCU grace period before inserting
inetpeer tree into gc_list and waking the worker. At that time, no
concurrent lookup can find a inetpeer in this tree.

Signed-off-by: Eric Dumazet 
Cc: Steffen Klassert 
Acked-by: Steffen Klassert 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

route: Remove redirect_genid

2012-03-08T08:30:32+00:00

As we invalidate the inetpeer tree along with the routing cache now,
we don't need a genid to reset the redirect handling when the routing
cache is flushed.

Signed-off-by: Steffen Klassert 
Signed-off-by: David S. Miller

inetpeer: Invalidate the inetpeer tree along with the routing cache

2012-03-08T08:30:24+00:00

We initialize the routing metrics with the values cached on the
inetpeer in rt_init_metrics(). So if we have the metrics cached on the
inetpeer, we ignore the user configured fib_metrics.

To fix this issue, we replace the old tree with a fresh initialized
inet_peer_base. The old tree is removed later with a delayed work queue.

Signed-off-by: Steffen Klassert 
Signed-off-by: David S. Miller

inetpeer: initialize ->redirect_genid in inet_getpeer()

2012-01-17T20:52:12+00:00

kmemcheck complains that ->redirect_genid doesn't get initialized.
Presumably it should be set to zero.

Signed-off-by: Dan Carpenter 
Signed-off-by: David S. Miller

net: fix some sparse errors

2012-01-17T15:31:12+00:00

make C=2 CF="-D__CHECK_ENDIAN__" M=net

And fix flowi4_init_output() prototype for sport

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: Compute protocol sequence numbers and fragment IDs using MD5.

2011-08-07T01:33:19+00:00

Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.

MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)

Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation.  So the periodic
regeneration and 8-bit counter have been removed.  We compute and
use a full 32-bit sequence number.

For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.

Reported-by: Dan Kaminsky 
Tested-by: Willy Tarreau 
Signed-off-by: David S. Miller

ipv6: make fragment identifications less predictable

2011-07-22T04:25:58+00:00

IPv6 fragment identification generation is way beyond what we use for
IPv4 : It uses a single generator. Its not scalable and allows DOS
attacks.

Now inetpeer is IPv6 aware, we can use it to provide a more secure and
scalable frag ident generator (per destination, instead of system wide)

This patch :
1) defines a new secure_ipv6_id() helper
2) extends inet_getid() to provide 32bit results
3) extends ipv6_select_ident() with a new dest parameter

Reported-by: Fernando Gont 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inetpeer: kill inet_putpeer race

2011-07-12T03:25:04+00:00

We currently can free inetpeer entries too early :

[  782.636674] WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (f130f44c)
[  782.636677] 1f7b13c100000000000000000000000002000000000000000000000000000000
[  782.636686]  i i i i u u u u i i i i u u u u i i i i u u u u u u u u u u u u
[  782.636694]                          ^
[  782.636696]
[  782.636698] Pid: 4638, comm: ssh Not tainted 3.0.0-rc5+ #270 Hewlett-Packard HP Compaq 6005 Pro SFF PC/3047h
[  782.636702] EIP: 0060:[] EFLAGS: 00010286 CPU: 0
[  782.636707] EIP is at inet_getpeer+0x25b/0x5a0
[  782.636709] EAX: 00000002 EBX: 00010080 ECX: f130f3c0 EDX: f0209d30
[  782.636711] ESI: 0000bc87 EDI: 0000ea60 EBP: f0209ddc ESP: c173134c
[  782.636712]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  782.636714] CR0: 8005003b CR2: f0beca80 CR3: 30246000 CR4: 000006d0
[  782.636716] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  782.636717] DR6: ffff4ff0 DR7: 00000400
[  782.636718]  [] rt_set_nexthop.clone.45+0x56/0x220
[  782.636722]  [] __ip_route_output_key+0x309/0x860
[  782.636724]  [] tcp_v4_connect+0x124/0x450
[  782.636728]  [] inet_stream_connect+0xa3/0x270
[  782.636731]  [] sys_connect+0xa1/0xb0
[  782.636733]  [] sys_socketcall+0x25d/0x2a0
[  782.636736]  [] sysenter_do_call+0x12/0x28
[  782.636738]  [] 0xffffffff

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller