Since we reverted 30902dc3cb0ea1cfc7ac2b17bcf478ff98420d74 ("ax25: Fix
std timer socket destroy handling.") we have to put some kind of fix
in to cure the issue whereby unaccepted connections do not get destroyed.

The approach used here is from Tihomir Heidelberg - 9a4gl

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

This reverts commit 30902dc3cb0ea1cfc7ac2b17bcf478ff98420d74.

It causes all kinds of problems, based upon a report by
Bernard (f6bvp) and analysis by Jarek Poplawski.

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

Since 49ffcf8f99e8d33ec8afb450956804af518fd788 ("sysctl: update
sysctl_check_table") setting struct ctl_table.procname = NULL does no
longer work as it used to the way the AX.25 code is expecting it to
resulting in the AX.25 sysctl registration code to break if
CONFIG_AX25_DAMA_SLAVE was not set as in some distribution kernels.
Kernel releases from 2.6.24 are affected.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Without CONFIG_NET_NS, namespace is always &init_net.
Compiler will be able to omit namespace comparisons with this patch.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Tihomir Heidelberg - 9a4gl, reports:

--------------------
I would like to direct you attention to one problem existing in ax.25
kernel since 2.4. If listening socket is closed and its SKB queue is
released but those sockets get weird. Those "unAccepted()" sockets
should be destroyed in ax25_std_heartbeat_expiry, but it will not
happen. And there is also a note about that in ax25_std_timer.c:
/* Magic here: If we listen() and a new link dies before it
is accepted() it isn't 'dead' so doesn't get removed. */

This issue cause ax25d to stop accepting new connections and I had to
restarted ax25d approximately each day and my services were unavailable.
Also netstat -n -l shows invalid source and device for those listening
sockets. It is strange why ax25d's listening socket get weird because of
this issue, but definitely when I solved this bug I do not have problems
with ax25d anymore and my ax25d can run for months without problems.
--------------------

Actually as far as I can see, this problem is even in releases
as far back as 2.2.x as well.

It seems senseless to special case this test on TCP_LISTEN state.
Anything still stuck in state 0 has no external references and
we can just simply kill it off directly.

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

The way that listening sockets work in ax25 is that the packet input
code path creates new socks via ax25_make_new() and attaches them
to the incoming SKB.  This SKB gets queued up into the listening
socket's receive queue.

When accept()'d the sock gets hooked up to the real parent socket.
Alternatively, if the listening socket is closed and released, any
unborn socks stuff up in the receive queue get released.

So during this time period these sockets are unreachable in any
other way, so no wakeup events nor references to their ->sk_socket
and ->sk_sleep members can occur.  And even if they do, all such
paths have to make NULL checks.

So do not deceptively initialize them in ax25_make_new() to the
values in the listening socket.  Leave them at NULL.

Finally, use sock_graft() in ax25_accept().

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

From: Jarek Poplawski <jarkao2@gmail.com>

There is only one function in AX25 calling skb_append(), and it really
looks suspicious: appends skb after previously enqueued one, but in
the meantime this previous skb could be removed from the queue.

This patch Fixes it the simple way, so this is not fully compatible with
the current method, but testing hasn't shown any problems.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

	drivers/net/ehea/ehea_main.c
	drivers/net/wireless/iwlwifi/Kconfig
	drivers/net/wireless/rt2x00/rt61pci.c
	net/ipv4/inet_timewait_sock.c
	net/ipv6/raw.c
	net/mac80211/ieee80211_sta.c

The ax25_uid_free call walks the ax25_uid_list and releases entries
from it. The problem is that after the fisrt call to hlist_del_init
the hlist_for_each_entry (which hides behind the ax25_uid_for_each)
will consider the current position to be the last and will return.

Thus, the whole list will be left not freed.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

	drivers/net/usb/rndis_host.c
	drivers/net/wireless/b43/dma.c
	net/ipv6/ndisc.c