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>

Add missing .owner of struct pppox_proto. This prevents the
module from being removed from underneath its users.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

PPPoL2TP sockets should comply with the standard send*() return values
(i.e. return number of bytes sent instead of 0 upon success).

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Copy user data after PPP framing header. This prevents erasure of the
added PPP header and avoids leaking two bytes of uninitialised memory
at the end of skb's data buffer.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	drivers/nfc/microread/mei.c
	net/netfilter/nfnetlink_queue_core.c

Pull in 'net' to get Eric Biederman's AF_UNIX fix, upon which
some cleanups are going to go on-top.

Signed-off-by: David S. Miller <davem@davemloft.net>

The L2TP code for IPv6 fails to initialize the l2tp_conn_id member of
struct sockaddr_l2tpip6 and therefore leaks four bytes kernel stack
in l2tp_ip6_recvmsg() in case msg_name is set.

Initialize l2tp_conn_id with 0 to avoid the info leak.

Signed-off-by: Mathias Krause <minipli@googlemail.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>