l2tp_tunnel_find() and l2tp_tunnel_find_nth() don't modify "net".
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make l2tp_pernet()'s parameter constant, so that l2tp_session_get*() can
declare their "net" variable as "const".
Also constify "ifname" in l2tp_session_get_by_ifname().
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Take a reference on the sessions returned by l2tp_session_find_nth()
(and rename it l2tp_session_get_nth() to reflect this change), so that
caller is assured that the session isn't going to disappear while
processing it.
For procfs and debugfs handlers, the session is held in the .start()
callback and dropped in .show(). Given that pppol2tp_seq_session_show()
dereferences the associated PPPoL2TP socket and that
l2tp_dfs_seq_session_show() might call pppol2tp_show(), we also need to
call the session's .ref() callback to prevent the socket from going
away from under us.
Fixes: fd558d186d ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Fixes: 0ad6614048 ("l2tp: Add debugfs files for dumping l2tp debug info")
Fixes: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Callers of l2tp_nl_session_find() need to hold a reference on the
returned session since there's no guarantee that it isn't going to
disappear from under them.
Relying on the fact that no l2tp netlink message may be processed
concurrently isn't enough: sessions can be deleted by other means
(e.g. by closing the PPPOL2TP socket of a ppp pseudowire).
l2tp_nl_cmd_session_delete() is a bit special: it runs a callback
function that may require a previous call to session->ref(). In
particular, for ppp pseudowires, the callback is l2tp_session_delete(),
which then calls pppol2tp_session_close() and dereferences the PPPOL2TP
socket. The socket might already be gone at the moment
l2tp_session_delete() calls session->ref(), so we need to take a
reference during the session lookup. So we need to pass the do_ref
variable down to l2tp_session_get() and l2tp_session_get_by_ifname().
Since all callers have to be updated, l2tp_session_find_by_ifname() and
l2tp_nl_session_find() are renamed to reflect their new behaviour.
Fixes: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
l2tp_session_create() relies on its caller for checking for duplicate
sessions. This is racy since a session can be concurrently inserted
after the caller's verification.
Fix this by letting l2tp_session_create() verify sessions uniqueness
upon insertion. Callers need to be adapted to check for
l2tp_session_create()'s return code instead of calling
l2tp_session_find().
pppol2tp_connect() is a bit special because it has to work on existing
sessions (if they're not connected) or to create a new session if none
is found. When acting on a preexisting session, a reference must be
held or it could go away on us. So we have to use l2tp_session_get()
instead of l2tp_session_find() and drop the reference before exiting.
Fixes: d9e31d17ce ("l2tp: Add L2TP ethernet pseudowire support")
Fixes: fd558d186d ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Taking a reference on sessions in l2tp_recv_common() is racy; this
has to be done by the callers.
To this end, a new function is required (l2tp_session_get()) to
atomically lookup a session and take a reference on it. Callers then
have to manually drop this reference.
Fixes: fd558d186d ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.
Use BUILD_BUG_ON in a couple ATM drivers.
In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement. Hopefully this patch inspires
someone else to trim vsprintf.c more.
Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While destroying a network namespace that contains a L2TP tunnel a
"BUG: scheduling while atomic" can be observed.
Enabling lockdep shows that this is happening because l2tp_exit_net()
is calling l2tp_tunnel_closeall() (via l2tp_tunnel_delete()) from
within an RCU critical section.
l2tp_exit_net() takes rcu_read_lock_bh()
<< list_for_each_entry_rcu() >>
l2tp_tunnel_delete()
l2tp_tunnel_closeall()
__l2tp_session_unhash()
synchronize_rcu() << Illegal inside RCU critical section >>
BUG: sleeping function called from invalid context
in_atomic(): 1, irqs_disabled(): 0, pid: 86, name: kworker/u16:2
INFO: lockdep is turned off.
CPU: 2 PID: 86 Comm: kworker/u16:2 Tainted: G W O 4.4.6-at1 #2
Hardware name: Xen HVM domU, BIOS 4.6.1-xs125300 05/09/2016
Workqueue: netns cleanup_net
0000000000000000 ffff880202417b90 ffffffff812b0013 ffff880202410ac0
ffffffff81870de8 ffff880202417bb8 ffffffff8107aee8 ffffffff81870de8
0000000000000c51 0000000000000000 ffff880202417be0 ffffffff8107b024
Call Trace:
[<ffffffff812b0013>] dump_stack+0x85/0xc2
[<ffffffff8107aee8>] ___might_sleep+0x148/0x240
[<ffffffff8107b024>] __might_sleep+0x44/0x80
[<ffffffff810b21bd>] synchronize_sched+0x2d/0xe0
[<ffffffff8109be6d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff8105c7bb>] ? __local_bh_enable_ip+0x6b/0xc0
[<ffffffff816a1b00>] ? _raw_spin_unlock_bh+0x30/0x40
[<ffffffff81667482>] __l2tp_session_unhash+0x172/0x220
[<ffffffff81667397>] ? __l2tp_session_unhash+0x87/0x220
[<ffffffff8166888b>] l2tp_tunnel_closeall+0x9b/0x140
[<ffffffff81668c74>] l2tp_tunnel_delete+0x14/0x60
[<ffffffff81668dd0>] l2tp_exit_net+0x110/0x270
[<ffffffff81668d5c>] ? l2tp_exit_net+0x9c/0x270
[<ffffffff815001c3>] ops_exit_list.isra.6+0x33/0x60
[<ffffffff81501166>] cleanup_net+0x1b6/0x280
...
This bug can easily be reproduced with a few steps:
$ sudo unshare -n bash # Create a shell in a new namespace
# ip link set lo up
# ip addr add 127.0.0.1 dev lo
# ip l2tp add tunnel remote 127.0.0.1 local 127.0.0.1 tunnel_id 1 \
peer_tunnel_id 1 udp_sport 50000 udp_dport 50000
# ip l2tp add session name foo tunnel_id 1 session_id 1 \
peer_session_id 1
# ip link set foo up
# exit # Exit the shell, in turn exiting the namespace
$ dmesg
...
[942121.089216] BUG: scheduling while atomic: kworker/u16:3/13872/0x00000200
...
To fix this, move the call to l2tp_tunnel_closeall() out of the RCU
critical section, and instead call it from l2tp_tunnel_del_work(), which
is running from the l2tp_wq workqueue.
Fixes: 2b551c6e7d ("l2tp: close sessions before initiating tunnel delete")
Signed-off-by: Ridge Kennedy <ridge.kennedy@alliedtelesis.co.nz>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
recv_seq, send_seq and lns_mode mode are all defined as
unsigned int foo:1;
Signed-off-by: Asbjoern Sloth Toennesen <asbjorn@asbjorn.st>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tunnel deletion is delayed by both a workqueue (l2tp_tunnel_delete -> wq
-> l2tp_tunnel_del_work) and RCU (sk_destruct -> RCU ->
l2tp_tunnel_destruct).
By the time l2tp_tunnel_destruct() runs to destroy the tunnel and finish
destroying the socket, the private data reserved via the net_generic
mechanism has already been freed, but l2tp_tunnel_destruct() actually
uses this data.
Make sure tunnel deletion for the netns has completed before returning
from l2tp_exit_net() by first flushing the tunnel removal workqueue, and
then waiting for RCU callbacks to complete.
Fixes: 167eb17e0b ("l2tp: create tunnel sockets in the right namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes a bug which causes the behavior of whether to ignore
udp6 checksum of udp6 encapsulated l2tp tunnel contrary to what
userspace program requests.
When the flag `L2TP_ATTR_UDP_ZERO_CSUM6_RX` is set by userspace, it is
expected that udp6 checksums of received packets of the l2tp tunnel
to create should be ignored. In `l2tp_netlink.c`:
`l2tp_nl_cmd_tunnel_create()`, `cfg.udp6_zero_rx_checksums` is set
according to the flag, and then passed to `l2tp_core.c`:
`l2tp_tunnel_create()` and then `l2tp_tunnel_sock_create()`. In
`l2tp_tunnel_sock_create()`, `udp_conf.use_udp6_rx_checksums` is set
the same to `cfg.udp6_zero_rx_checksums`. However, if we want the
checksum to be ignored, `udp_conf.use_udp6_rx_checksums` should be set
to `false`, i.e. be set to the contrary. Similarly, the same should be
done to `udp_conf.use_udp6_tx_checksums`.
Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a small chance that tunnel_free() is called before tunnel->del_work scheduled
resulting in a zero pointer dereference.
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that sk_alloc knows when a kernel socket is being allocated modify
it to not reference count the network namespace of kernel sockets.
Keep track of if a socket needs reference counting by adding a flag to
struct sock called sk_net_refcnt.
Update all of the callers of sock_create_kern to stop using
sk_change_net and sk_release_kernel as those hacks are no longer
needed, to avoid reference counting a kernel socket.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is long overdue, and is part of cleaning up how we allocate kernel
sockets that don't reference count struct net.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Simplify l2tp implementation using common UDP tunnel APIs.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This syntax error was covered by L2TP_REFCNT_DEBUG not being set by
default.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In l2tp driver call common function udp_sock_create to create the
listener UDP port.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Call common functions to set checksum for UDP tunnel.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Added new L2TP configuration options to allow TX and RX of
zero checksums in IPv6. Default is not to use them.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define separate fields in the sock structure for configuring disabling
checksums in both TX and RX-- sk_no_check_tx and sk_no_check_rx.
The SO_NO_CHECK socket option only affects sk_no_check_tx. Also,
removed UDP_CSUM_* defines since they are no longer necessary.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As suggested by several people, rename local_df to ignore_df,
since it means "ignore df bit if it is set".
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Validating the UDP checksum is now done in UDP before handing
packets to the encapsulation layer. Note that this also eliminates
the "feature" where L2TP can ignore a non-zero UDP checksum (doing
this was contrary to RFC 1122).
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_queue_xmit() assumes the skb it has to transmit is attached to an
inet socket. Commit 31c70d5956 ("l2tp: keep original skb ownership")
changed l2tp to not change skb ownership and thus broke this assumption.
One fix is to add a new 'struct sock *sk' parameter to ip_queue_xmit(),
so that we do not assume skb->sk points to the socket used by l2tp
tunnel.
Fixes: 31c70d5956 ("l2tp: keep original skb ownership")
Reported-by: Zhan Jianyu <nasa4836@gmail.com>
Tested-by: Zhan Jianyu <nasa4836@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking updates from David Miller:
"Here is my initial pull request for the networking subsystem during
this merge window:
1) Support for ESN in AH (RFC 4302) from Fan Du.
2) Add full kernel doc for ethtool command structures, from Ben
Hutchings.
3) Add BCM7xxx PHY driver, from Florian Fainelli.
4) Export computed TCP rate information in netlink socket dumps, from
Eric Dumazet.
5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
Dichtel.
6) Convert many drivers to pci_enable_msix_range(), from Alexander
Gordeev.
7) Record SKB timestamps more efficiently, from Eric Dumazet.
8) Switch to microsecond resolution for TCP round trip times, also
from Eric Dumazet.
9) Clean up and fix 6lowpan fragmentation handling by making use of
the existing inet_frag api for it's implementation.
10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.
11) Auto size SKB lengths when composing netlink messages based upon
past message sizes used, from Eric Dumazet.
12) qdisc dumps can take a long time, add a cond_resched(), From Eric
Dumazet.
13) Sanitize netpoll core and drivers wrt. SKB handling semantics.
Get rid of never-used-in-tree netpoll RX handling. From Eric W
Biederman.
14) Support inter-address-family and namespace changing in VTI tunnel
driver(s). From Steffen Klassert.
15) Add Altera TSE driver, from Vince Bridgers.
16) Optimizing csum_replace2() so that it doesn't adjust the checksum
by checksumming the entire header, from Eric Dumazet.
17) Expand BPF internal implementation for faster interpreting, more
direct translations into JIT'd code, and much cleaner uses of BPF
filtering in non-socket ocntexts. From Daniel Borkmann and Alexei
Starovoitov"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
net: Add a test to see if a skb is freeable in irq context
qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
net: ptp: move PTP classifier in its own file
net: sxgbe: make "core_ops" static
net: sxgbe: fix logical vs bitwise operation
net: sxgbe: sxgbe_mdio_register() frees the bus
Call efx_set_channels() before efx->type->dimension_resources()
xen-netback: disable rogue vif in kthread context
net/mlx4: Set proper build dependancy with vxlan
be2net: fix build dependency on VxLAN
mac802154: make csma/cca parameters per-wpan
mac802154: allow only one WPAN to be up at any given time
net: filter: minor: fix kdoc in __sk_run_filter
netlink: don't compare the nul-termination in nla_strcmp
can: c_can: Avoid led toggling for every packet.
can: c_can: Simplify TX interrupt cleanup
can: c_can: Store dlc private
can: c_can: Reduce register access
can: c_can: Make the code readable
...
Pull workqueue changes from Tejun Heo:
"PREPARE_[DELAYED_]WORK() were used to change the work function of work
items without fully reinitializing it; however, this makes workqueue
consider the work item as a different one from before and allows the
work item to start executing before the previous instance is finished
which can lead to extremely subtle issues which are painful to debug.
The interface has never been popular. This pull request contains
patches to remove existing usages and kill the interface. As one of
the changes was routed during the last devel cycle and another
depended on a pending change in nvme, for-3.15 contains a couple merge
commits.
In addition, interfaces which were deprecated quite a while ago -
__cancel_delayed_work() and WQ_NON_REENTRANT - are removed too"
* 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: remove deprecated WQ_NON_REENTRANT
workqueue: Spelling s/instensive/intensive/
workqueue: remove PREPARE_[DELAYED_]WORK()
staging/fwserial: don't use PREPARE_WORK
afs: don't use PREPARE_WORK
nvme: don't use PREPARE_WORK
usb: don't use PREPARE_DELAYED_WORK
floppy: don't use PREPARE_[DELAYED_]WORK
ps3-vuart: don't use PREPARE_WORK
wireless/rt2x00: don't use PREPARE_WORK in rt2800usb.c
workqueue: Remove deprecated __cancel_delayed_work()
Tejun Heo has made WQ_NON_REENTRANT useless in the dbf2576e37
("workqueue: make all workqueues non-reentrant"). So remove its
usages and definition.
This patch doesn't introduce any behavior changes.
tj: minor description updates.
Signed-off-by: ZhangZhen <zhenzhang.zhang@huawei.com>
Sigend-off-by: Tejun Heo <tj@kernel.org>
Acked-by: James Chapman <jchapman@katalix.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Conflicts:
drivers/net/usb/r8152.c
drivers/net/xen-netback/netback.c
Both the r8152 and netback conflicts were simple overlapping
changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp/l2tp_core.c:1111:15: warning: unused variable
'sk' [-Wunused-variable]
Fixes: 31c70d5956 ("l2tp: keep original skb ownership")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no reason to orphan skb in l2tp.
This breaks things like per socket memory limits, TCP Small queues...
Fix this before more people copy/paste it.
This is very similar to commit 8f646c922d
("vxlan: keep original skb ownership")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit e0d4435f "l2tp: Update PPP-over-L2TP driver to work over L2TPv3"
broke the PPPOL2TP_SO_SENDSEQ setsockopt. The L2TP header length was
previously computed by pppol2tp_l2t_header_len() before each call to
l2tp_xmit_skb(). Now that header length is retrieved from the hdr_len
session field, this field must be updated every time the L2TP header
format is modified, or l2tp_xmit_skb() won't push the right amount of
data for the L2TP header.
This patch uses l2tp_session_set_header_len() to adjust hdr_len every
time sequencing is (de)activated from userspace (either by the
PPPOL2TP_SO_SENDSEQ setsockopt or the L2TP_ATTR_SEND_SEQ netlink
attribute).
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
One of my pet coding style peeves is the practice of
adding extra return; at the end of function.
Kill several instances of this in network code.
I suppose some coccinelle wizardy could do this automatically.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Avoid needless export of local functions
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCP listener refactoring, part 4 :
To speed up inet lookups, we moved IPv4 addresses from inet to struct
sock_common
Now is time to do the same for IPv6, because it permits us to have fast
lookups for all kind of sockets, including upcoming SYN_RECV.
Getting IPv6 addresses in TCP lookups currently requires two extra cache
lines, plus a dereference (and memory stall).
inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6
This patch is way bigger than its IPv4 counter part, because for IPv4,
we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6,
it's not doable easily.
inet6_sk(sk)->daddr becomes sk->sk_v6_daddr
inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr
And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr
at the same offset.
We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic
macro.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp/l2tp_core.c: In function ‘l2tp_verify_udp_checksum’:
net/l2tp/l2tp_core.c:499:22: warning: unused variable ‘tunnel’ [-Wunused-variable]
Create a helper "l2tp_tunnel()" to facilitate this, and as a side
effect get rid of a bunch of unnecessary void pointer casts.
Signed-off-by: David S. Miller <davem@davemloft.net>
If L2TP data sequence numbers are enabled and reordering is not
enabled, data reception stops if a packet is lost since the kernel
waits for a sequence number that is never resent. (When reordering is
enabled, data reception restarts when the reorder timeout expires.) If
no reorder timeout is set, we should count the number of in-sequence
packets after the out-of-sequence (OOS) condition is detected, and reset
sequence number state after a number of such packets are received.
For now, the number of in-sequence packets while in OOS state which
cause the sequence number state to be reset is hard-coded to 5. This
could be configurable later.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The L2TP datapath is not currently RFC-compliant when sequence numbers
are used in L2TP data packets. According to the L2TP RFC, any received
sequence number NR greater than or equal to the next expected NR is
acceptable, where the "greater than or equal to" test is determined by
the NR wrap point. This differs for L2TPv2 and L2TPv3, so add state in
the session context to hold the max NR value and the NR window size in
order to do the acceptable sequence number value check. These might be
configurable later, but for now we derive it from the tunnel L2TP
version, which determines the sequence number field size.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change moves some code handling data sequence numbers into a
separate function to avoid too much indentation. This is to prepare
for some changes to data sequence number handling in subsequent
patches.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a cut and paste typo. We call ->ref() a second time instead
of ->deref().
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If we postpone unhashing of l2tp sessions until the structure is freed, we
risk:
1. further packets arriving and getting queued while the pseudowire is being
closed down
2. the recv path hitting "scheduling while atomic" errors in the case that
recv drops the last reference to a session and calls l2tp_session_free
while in atomic context
As such, l2tp sessions should be unhashed from l2tp_core data structures early
in the teardown process prior to calling pseudowire close. For pseudowires
like l2tp_ppp which have multiple shutdown codepaths, provide an unhash hook.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
l2tp's u64_stats writers were incorrectly synchronised, making it possible to
deadlock a 64bit machine running a 32bit kernel simply by sending the l2tp
code netlink commands while passing data through l2tp sessions.
Previous discussion on netdev determined that alternative solutions such as
spinlock writer synchronisation or per-cpu data would bring unjustified
overhead, given that most users interested in high volume traffic will likely
be running 64bit kernels on 64bit hardware.
As such, this patch replaces l2tp's use of u64_stats with atomic_long_t,
thereby avoiding the deadlock.
Ref:
http://marc.info/?l=linux-netdev&m=134029167910731&w=2http://marc.info/?l=linux-netdev&m=134079868111131&w=2
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add calls to l2tp_session_queue_purge as a part of l2tp_tunnel_closeall
and l2tp_session_delete. Pseudowire implementations which are deleted only
via. l2tp_core l2tp_session_delete calls can dispense with their own code for
flushing the reorder queue.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an l2tp session is deleted, it is necessary to delete skbs in-flight
on the session's reorder queue before taking it down.
Rather than having each pseudowire implementation reaching into the
l2tp_session struct to handle this itself, provide a function in l2tp_core to
purge the session queue.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is valid for an existing struct sock object to have a NULL sk_socket
pointer, so don't BUG_ON in l2tp_tunnel_del_work if that should occur.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When looking up the tunnel socket in struct l2tp_tunnel, hold a reference
whether the socket was created by the kernel or by userspace.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When a user deletes a tunnel using netlink, all the sessions in the tunnel
should also be deleted. Since running sessions will pin the tunnel socket
with the references they hold, have the l2tp_tunnel_delete close all sessions
in a tunnel before finally closing the tunnel socket.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
