Its illegal to dereference skb after giving it to l2tp_xmit_skb()
as it might be already freed/reused.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 081b1b1bb2 (l2tp: fix l2tp_ip_sendmsg() route handling) added
a race, in case IP route cache is disabled.
In this case, we should not do the dst_release(&rt->dst), since it'll
free the dst immediately, instead of waiting a RCU grace period.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Cc: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: David S. Miller <davem@davemloft.net>
We must prevent module unloading if some devices are still attached to
l2tp_eth driver.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Generic netlink searches for -type- formatted aliases when requesting a module to
fulfill a protocol request (i.e. net-pf-16-proto-16-type-<x>, where x is a type
value). However generic netlink protocols have no well defined type numbers,
they have string names. Modify genl_ctrl_getfamily to request an alias in the
format net-pf-16-proto-16-family-<x> instead, where x is a generic string, and
add a macro that builds on the previously added MODULE_ALIAS_NET_PF_PROTO_NAME
macro to allow modules to specifify those generic strings.
Note, l2tp previously hacked together an net-pf-16-proto-16-type-l2tp alias
using the MODULE_ALIAS macro, with these updates we can convert that to use the
PROTO_NAME macro.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: James Chapman <jchapman@katalix.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
An application may call connect() to disconnect a socket using an
address with family AF_UNSPEC. The L2TP IP sockets were not handling
this case when the socket is not bound and an attempt to connect()
using AF_UNSPEC in such cases would result in an oops. This patch
addresses the problem by protecting the sk_prot->disconnect() call
against trying to unhash the socket before it is bound.
The L2TP IPv4 and IPv6 sockets have the same problem. Both are fixed
by this patch.
The patch also adds more checks that the sockaddr supplied to bind()
and connect() calls is valid.
RIP: 0010:[<ffffffff82e133b0>] [<ffffffff82e133b0>] inet_unhash+0x50/0xd0
RSP: 0018:ffff88001989be28 EFLAGS: 00010293
Stack:
ffff8800407a8000 0000000000000000 ffff88001989be78 ffffffff82e3a249
ffffffff82e3a050 ffff88001989bec8 ffff88001989be88 ffff8800407a8000
0000000000000010 ffff88001989bec8 ffff88001989bea8 ffffffff82e42639
Call Trace:
[<ffffffff82e3a249>] udp_disconnect+0x1f9/0x290
[<ffffffff82e42639>] inet_dgram_connect+0x29/0x80
[<ffffffff82d012fc>] sys_connect+0x9c/0x100
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use more current logging styles.
Add pr_fmt to prefix output appropriately.
Convert printks to pr_<level>.
Convert PRINTK macros to new l2tp_<level> macros.
Neaten some <foo>_refcount debugging macros.
Use print_hex_dump_bytes instead of hand-coded loops.
Coalesce formats and align arguments.
Some KERN_DEBUG output is not now emitted unless
dynamic_debugging is enabled.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If enabled, L2TP data packets have sequence numbers which a receiver
can use to drop out of sequence frames or try to reorder them. The
first frame has sequence number 0, but the L2TP code currently expects
it to be 1. This results in the first data frame being handled as out
of sequence.
This one-line patch fixes the problem.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When L2TP data packet reordering is enabled, packets are held in a
queue while waiting for out-of-sequence packets. If a packet gets
lost, packets will be held until the reorder timeout expires, when we
are supposed to then advance to the sequence number of the next packet
but we don't currently do so. As a result, the data channel is stuck
because we are waiting for a packet that will never arrive - all
packets age out and none are passed.
The fix is to add a flag to the session context, which is set when the
reorder timeout expires and tells the receive code to reset the next
expected sequence number to that of the next packet in the queue.
Tested in a production L2TP network with Starent and Nortel L2TP gear.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/intel/e1000e/param.c
drivers/net/wireless/iwlwifi/iwl-agn-rx.c
drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
drivers/net/wireless/iwlwifi/iwl-trans.h
Resolved the iwlwifi conflict with mainline using 3-way diff posted
by John Linville and Stephen Rothwell. In 'net' we added a bug
fix to make iwlwifi report a more accurate skb->truesize but this
conflicted with RX path changes that happened meanwhile in net-next.
In e1000e a conflict arose in the validation code for settings of
adapter->itr. 'net-next' had more sophisticated logic so that
logic was used.
Signed-off-by: David S. Miller <davem@davemloft.net>
l2tp_ip_sendmsg could return without releasing socket lock, making it all the
way to userspace, and generating the following warning:
[ 130.891594] ================================================
[ 130.894569] [ BUG: lock held when returning to user space! ]
[ 130.897257] 3.4.0-rc5-next-20120501-sasha #104 Tainted: G W
[ 130.900336] ------------------------------------------------
[ 130.902996] trinity/8384 is leaving the kernel with locks still held!
[ 130.906106] 1 lock held by trinity/8384:
[ 130.907924] #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff82b9503f>] l2tp_ip_sendmsg+0x2f/0x550
Introduced by commit 2f16270 ("l2tp: Fix locking in l2tp_ip.c").
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The netlink API lets users create unmanaged L2TPv3 tunnels using
iproute2. Until now, a request to create an unmanaged L2TPv3 IP
encapsulation tunnel over IPv6 would be rejected with
EPROTONOSUPPORT. Now that l2tp_ip6 implements sockets for L2TP IP
encapsulation over IPv6, we can add support for that tunnel type.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
L2TPv3 defines an IP encapsulation packet format where data is carried
directly over IP (no UDP). The kernel already has support for L2TP IP
encapsulation over IPv4 (l2tp_ip). This patch introduces support for
L2TP IP encapsulation over IPv6.
The implementation is derived from ipv6/raw and ipv4/l2tp_ip.
Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for unmanaged L2TPv3 tunnels over IPv6 using
the netlink API. We already support unmanaged L2TPv3 tunnels over
IPv4. A patch to iproute2 to make use of this feature will be
submitted separately.
Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an L2TP tunnel uses IPv6, make sure the l2tp debugfs file shows the
IPv6 address correctly.
Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Userspace uses connect() to associate a pppol2tp socket with a tunnel
socket. This needs to allow the caller to supply the new IPv6
sockaddr_pppol2tp structures if IPv6 is used.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The l2tp_ip socket currently maintains packet/byte stats in its
private socket structure. But these counters aren't exposed to
userspace and so serve no purpose. The counters were also
smp-unsafe. So this patch just gets rid of the stats.
While here, change a couple of internal __u32 variables to u32.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cleanup the l2tp_ip code to make use of an existing ipv4 support function.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
L2TP uses 64-bit counters but since these are not updated atomically,
we need to make them safe for smp. This patch addresses that.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that encap_rcv() works on IPv6 UDP sockets, wire L2TP up to IPv6.
Support has been tested with and without hardware offloading. This
version fixes the L2TP over localhost issue with incorrect checksums
being reported.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most machines dont use UDP encapsulation (L2TP)
Adds a static_key so that udp_queue_rcv_skb() doesnt have to perform a
test if L2TP never setup the encap_rcv on a socket.
Idea of this patch came after Simon Horman proposal to add a hook on TCP
as well.
If static_key is not yet enabled, the fast path does a single JMP .
When static_key is enabled, JMP destination is patched to reach the real
encap_type/encap_rcv logic, possibly adding cache misses.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: dev@openvswitch.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull in the 'net' tree to get CAIF bug fixes upon which
the following set of CAIF feature patches depend.
Signed-off-by: David S. Miller <davem@davemloft.net>
Applications using L2TP/IP sockets want to be able to bind() an L2TP/IP
socket to set the local tunnel id while leaving the auto-assigned source
address alone. So if no source address is supplied, don't overwrite
the address already stored in the socket.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The l2tp_ip socket close handler does not update the module refcount
correctly which prevents module unload after the first bind() call on
an L2TPv3 IP encapulation socket.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These macros contain a hidden goto, and are thus extremely error
prone and make code hard to audit.
Signed-off-by: David S. Miller <davem@davemloft.net>
When L2TP is configured as a module, requests for L2TP sockets do not result
in the l2tp_ppp module being loaded. Fix this by adding the appropriate
MODULE_ALIAS to be recognized by pppox's request_module() call.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
While testing L2TP functionality, I came across a bug in getsockname(). The
IP address returned within the pppol2tp_addr's addr memember was not being
set to the IP address in use. This bug is caused by using inet_sk() on the
wrong socket (the L2TP socket rather than the underlying UDP socket), and was
likely introduced during the addition of L2TPv3 support.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since all that include/linux/if_ppp.h does is #include <linux/ppp-ioctl.h>,
this replaces the occurrences of #include <linux/if_ppp.h> with
#include <linux/ppp-ioctl.h>.
It also corrects an error in Documentation/networking/l2tp.txt, where
it referenced include/linux/if_ppp.h as the source of some definitions
that are actually now defined in include/linux/if_pppol2tp.h.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace usage of random_ether_addr() with eth_hw_addr_random()
to set addr_assign_type correctly to NET_ADDR_RANDOM.
Change the trivial cases.
v2: adapt to renamed eth_hw_addr_random()
Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
When a packet is received on an L2TP IP socket (L2TPv3 IP link
encapsulation), the l2tpip socket's backlog_rcv function calls
xfrm4_policy_check(). This is not necessary, since it was called
before the skb was added to the backlog. With CONFIG_NET_NS enabled,
xfrm4_policy_check() will oops if skb->dev is null, so this trivial
patch removes the call.
This bug has always been present, but only when CONFIG_NET_NS is
enabled does it cause problems. Most users are probably using UDP
encapsulation for L2TP, hence the problem has only recently
surfaced.
EIP: 0060:[<c12bb62b>] EFLAGS: 00210246 CPU: 0
EIP is at l2tp_ip_recvmsg+0xd4/0x2a7
EAX: 00000001 EBX: d77b5180 ECX: 00000000 EDX: 00200246
ESI: 00000000 EDI: d63cbd30 EBP: d63cbd18 ESP: d63cbcf4
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Call Trace:
[<c1218568>] sock_common_recvmsg+0x31/0x46
[<c1215c92>] __sock_recvmsg_nosec+0x45/0x4d
[<c12163a1>] __sock_recvmsg+0x31/0x3b
[<c1216828>] sock_recvmsg+0x96/0xab
[<c10b2693>] ? might_fault+0x47/0x81
[<c10b2693>] ? might_fault+0x47/0x81
[<c1167fd0>] ? _copy_from_user+0x31/0x115
[<c121e8c8>] ? copy_from_user+0x8/0xa
[<c121ebd6>] ? verify_iovec+0x3e/0x78
[<c1216604>] __sys_recvmsg+0x10a/0x1aa
[<c1216792>] ? sock_recvmsg+0x0/0xab
[<c105a99b>] ? __lock_acquire+0xbdf/0xbee
[<c12d5a99>] ? do_page_fault+0x193/0x375
[<c10d1200>] ? fcheck_files+0x9b/0xca
[<c10d1259>] ? fget_light+0x2a/0x9c
[<c1216bbb>] sys_recvmsg+0x2b/0x43
[<c1218145>] sys_socketcall+0x16d/0x1a5
[<c11679f0>] ? trace_hardirqs_on_thunk+0xc/0x10
[<c100305f>] sysenter_do_call+0x12/0x38
Code: c6 05 8c ea a8 c1 01 e8 0c d4 d9 ff 85 f6 74 07 3e ff 86 80 00 00 00 b9 17 b6 2b c1 ba 01 00 00 00 b8 78 ed 48 c1 e8 23 f6 d9 ff <ff> 76 0c 68 28 e3 30 c1 68 2d 44 41 c1 e8 89 57 01 00 83 c4 0c
Signed-off-by: James Chapman <jchapman@katalix.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using l2tp over ipsec, the tunnel will hang when rekeying
occurs. Reason is that the transformer bundle attached to the dst entry
is now in STATE_DEAD and thus xfrm_output_one() drops all packets
(XfrmOutStateExpired increases).
Fix this by calling __sk_dst_check (which drops the stale dst
if xfrm dst->check callback finds that the bundle is no longer valid).
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Misha Labjuk reported panics occurring in l2tp_recv_dequeue()
If we release reorder_q.lock, we must not keep a dangling pointer (tmp),
since another thread could manipulate reorder_q.
Instead we must restart the scan at beginning of list.
Reported-by: Misha Labjuk <spiked.yar@gmail.com>
Tested-by: Misha Labjuk <spiked.yar@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
pppol2tp_xmit() calls skb_cow_head(skb, 2) before calling
l2tp_xmit_skb()
Then l2tp_xmit_skb() calls again skb_cow_head(skb, large_headroom)
This patchs changes the first skb_cow_head() call to supply the needed
headroom to make sure at most one (expensive) pskb_expand_head() is
done.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
l2tp_xmit_skb() can leak one skb if skb_cow_head() returns an error.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (32 commits)
tg3: Remove 5719 jumbo frames and TSO blocks
tg3: Break larger frags into 4k chunks for 5719
tg3: Add tx BD budgeting code
tg3: Consolidate code that calls tg3_tx_set_bd()
tg3: Add partial fragment unmapping code
tg3: Generalize tg3_skb_error_unmap()
tg3: Remove short DMA check for 1st fragment
tg3: Simplify tx bd assignments
tg3: Reintroduce tg3_tx_ring_info
ASIX: Use only 11 bits of header for data size
ASIX: Simplify condition in rx_fixup()
Fix cdc-phonet build
bonding: reduce noise during init
bonding: fix string comparison errors
net: Audit drivers to identify those needing IFF_TX_SKB_SHARING cleared
net: add IFF_SKB_TX_SHARED flag to priv_flags
net: sock_sendmsg_nosec() is static
forcedeth: fix vlans
gianfar: fix bug caused by 87c288c6e9
gro: Only reset frag0 when skb can be pulled
...
After the last patch, We are left in a state in which only drivers calling
ether_setup have IFF_TX_SKB_SHARING set (we assume that drivers touching real
hardware call ether_setup for their net_devices and don't hold any state in
their skbs. There are a handful of drivers that violate this assumption of
course, and need to be fixed up. This patch identifies those drivers, and marks
them as not being able to support the safe transmission of skbs by clearning the
IFF_TX_SKB_SHARING flag in priv_flags
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Karsten Keil <isdn@linux-pingi.de>
CC: "David S. Miller" <davem@davemloft.net>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: Patrick McHardy <kaber@trash.net>
CC: Krzysztof Halasa <khc@pm.waw.pl>
CC: "John W. Linville" <linville@tuxdriver.com>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Marcel Holtmann <marcel@holtmann.org>
CC: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
l2tp_ip_sendmsg() in non connected mode incorrectly calls
sk_setup_caps(). Subsequent send() calls send data to wrong destination.
We can also avoid changing dst refcount in connected mode, using
appropriate rcu locking. Once output route lookups can also be done
under rcu, sendto() calls wont change dst refcounts too.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>
More fallout from struct net lifetime rules review: PTR_ERR() is *already*
negative and failing ->open() should return negatives on failure.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1446 commits)
macvlan: fix panic if lowerdev in a bond
tg3: Add braces around 5906 workaround.
tg3: Fix NETIF_F_LOOPBACK error
macvlan: remove one synchronize_rcu() call
networking: NET_CLS_ROUTE4 depends on INET
irda: Fix error propagation in ircomm_lmp_connect_response()
irda: Kill set but unused variable 'bytes' in irlan_check_command_param()
irda: Kill set but unused variable 'clen' in ircomm_connect_indication()
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_transport()
be2net: Kill set but unused variable 'req' in lancer_fw_download()
irda: Kill set but unused vars 'saddr' and 'daddr' in irlan_provider_connect_indication()
atl1c: atl1c_resume() is only used when CONFIG_PM_SLEEP is defined.
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_peer().
rxrpc: Kill set but unused variable 'local' in rxrpc_UDP_error_handler()
rxrpc: Kill set but unused variable 'sp' in rxrpc_process_connection()
rxrpc: Kill set but unused variable 'sp' in rxrpc_rotate_tx_window()
pkt_sched: Kill set but unused variable 'protocol' in tc_classify()
isdn: capi: Use pr_debug() instead of ifdefs.
tg3: Update version to 3.119
tg3: Apply rx_discards fix to 5719/5720
...
Fix up trivial conflicts in arch/x86/Kconfig and net/mac80211/agg-tx.c
as per Davem.
While trying to remove useless synchronize_rcu() calls, I found l2tp is
indeed incorrectly using two of such calls, but also bumps tunnel
refcount after list insertion.
tunnel refcount must be incremented before being made publically visible
by rcu readers.
This fix can be applied to 2.6.35+ and might need a backport for older
kernels, since things were shuffled in commit fd558d186d
(l2tp: Split pppol2tp patch into separate l2tp and ppp parts)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: James Chapman <jchapman@katalix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows us to acquire the exact route keying information from the
protocol, however that might be managed.
It handles all of the possibilities, from the simplest case of storing
the key in inet->cork.fl to the more complex setup SCTP has where
individual transports determine the flow.
Signed-off-by: David S. Miller <davem@davemloft.net>
l2tp_xmit_skb() must take the socket lock. It makes use of ip_queue_xmit()
which expects to execute in a socket atomic context.
Since we execute this function in software interrupts, we cannot use the
usual lock_sock()/release_sock() sequence, instead we have to use
bh_lock_sock() and see if a user has the socket locked, and if so drop
the packet.
Signed-off-by: David S. Miller <davem@davemloft.net>
Both l2tp_ip_connect() and l2tp_ip_sendmsg() must take the socket
lock. They both modify socket state non-atomically, and in particular
l2tp_ip_sendmsg() increments socket private counters without using
atomic operations.
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet