linux-toradex.git/net/ipv4/ipmr.c, branch v3.2.74

ipmr: fix possible race resulting from improper usage of IP_INC_STATS_BH() in preemptible context.

2015-11-27T12:48:25+00:00

[ Upstream commit 44f49dd8b5a606870a1f21101522a0f9c4414784 ]

Fixes the following kernel BUG :

BUG: using __this_cpu_add() in preemptible [00000000] code: bash/2758
caller is __this_cpu_preempt_check+0x13/0x15
CPU: 0 PID: 2758 Comm: bash Tainted: P           O   3.18.19 #2
 ffffffff8170eaca ffff880110d1b788 ffffffff81482b2a 0000000000000000
 0000000000000000 ffff880110d1b7b8 ffffffff812010ae ffff880007cab800
 ffff88001a060800 ffff88013a899108 ffff880108b84240 ffff880110d1b7c8
Call Trace:
[] dump_stack+0x52/0x80
[] check_preemption_disabled+0xce/0xe1
[] __this_cpu_preempt_check+0x13/0x15
[] ipmr_queue_xmit+0x647/0x70c
[] ip_mr_forward+0x32f/0x34e
[] ip_mroute_setsockopt+0xe03/0x108c
[] ? get_parent_ip+0x11/0x42
[] ? pollwake+0x4d/0x51
[] ? default_wake_function+0x0/0xf
[] ? get_parent_ip+0x11/0x42
[] ? __wake_up_common+0x45/0x77
[] ? _raw_spin_unlock_irqrestore+0x1d/0x32
[] ? __wake_up_sync_key+0x4a/0x53
[] ? sock_def_readable+0x71/0x75
[] do_ip_setsockopt+0x9d/0xb55
[] ? unix_seqpacket_sendmsg+0x3f/0x41
[] ? sock_sendmsg+0x6d/0x86
[] ? sockfd_lookup_light+0x12/0x5d
[] ? SyS_sendto+0xf3/0x11b
[] ? new_sync_read+0x82/0xaa
[] compat_ip_setsockopt+0x3b/0x99
[] compat_raw_setsockopt+0x11/0x32
[] compat_sock_common_setsockopt+0x18/0x1f
[] compat_SyS_setsockopt+0x1a9/0x1cf
[] compat_SyS_socketcall+0x180/0x1e3
[] cstar_dispatch+0x7/0x1e

Signed-off-by: Ani Sinha 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: ipmr doesn't implement IPSTATS_MIB_OUTOCTETS]
Signed-off-by: Ben Hutchings

inetpeer: get rid of ip_id_count

2014-09-13T22:41:48+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: Ben Hutchings

net: avoid reference counter overflows on fib_rules in multicast forwarding

2014-02-15T19:20:10+00:00

[ Upstream commit 95f4a45de1a0f172b35451fc52283290adb21f6e ]

Bob Falken reported that after 4G packets, multicast forwarding stopped
working. This was because of a rule reference counter overflow which
freed the rule as soon as the overflow happend.

This patch solves this by adding the FIB_LOOKUP_NOREF flag to
fib_rules_lookup calls. This is safe even from non-rcu locked sections
as in this case the flag only implies not taking a reference to the rule,
which we don't need at all.

Rules only hold references to the namespace, which are guaranteed to be
available during the call of the non-rcu protected function reg_vif_xmit
because of the interface reference which itself holds a reference to
the net namespace.

Fixes: f0ad0860d01e47 ("ipv4: ipmr: support multiple tables")
Fixes: d1db275dd3f6e4 ("ipv6: ip6mr: support multiple tables")
Reported-by: Bob Falken 
Cc: Patrick McHardy 
Cc: Thomas Graf 
Cc: Julian Anastasov 
Cc: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ip: generate unique IP identificator if local fragmentation is allowed

2013-10-26T20:06:08+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: Ben Hutchings

net: ipv4: ipmr_expire_timer causes crash when removing net namespace

2012-09-19T14:04:57+00:00

[ Upstream commit acbb219d5f53821b2d0080d047800410c0420ea1 ]

When tearing down a net namespace, ipv4 mr_table structures are freed
without first deactivating their timers. This can result in a crash in
run_timer_softirq.
This patch mimics the corresponding behaviour in ipv6.
Locking and synchronization seem to be adequate.
We are about to kfree mrt, so existing code should already make sure that
no other references to mrt are pending or can be created by incoming traffic.
The functions invoked here do not cause new references to mrt or other
race conditions to be created.
Invoking del_timer_sync guarantees that ipmr_expire_timer is inactive.
Both ipmr_expire_process (whose completion we may have to wait in
del_timer_sync) and mroute_clean_tables internally use mfc_unres_lock
or other synchronizations when needed, and they both only modify mrt.

Tested in Linux 3.4.8.

Signed-off-by: Francesco Ruggeri 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: reintroduce missing rcu_assign_pointer() calls

2012-02-03T17:22:20+00:00

[ Upstream commit cf778b00e96df6d64f8e21b8395d1f8a859ecdc7 ]

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet 
CC: Stephen Hemminger 
CC: Paul E. McKenney 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

2011-10-31T23:30:30+00:00

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker

net: cleanup some rcu_dereference_raw

2011-08-12T09:55:28+00:00

RCU api had been completed and rcu_access_pointer() or
rcu_dereference_protected() are better than generic
rcu_dereference_raw()

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

rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER

2011-08-02T11:29:23+00:00

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// 

Signed-off-by: Stephen Hemminger 
Acked-by: Paul E. McKenney 
Signed-off-by: David S. Miller

ipv4: use RT_TOS after some rt_tos conversions

2011-07-24T03:05:31+00:00

rt_tos was changed to iph->tos but it must be filtered by RT_TOS

Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller