linux-toradex.git/include/linux/netlink.h, branch v3.14.3

netlink: cleanup tap related functions

2014-01-02T04:43:36+00:00

Cleanups in netlink_tap code
 * remove unused function netlink_clear_multicast_users
 * make local function static

Signed-off-by: Stephen Hemminger 
Reviewed-by: Johannes Berg 
Signed-off-by: David S. Miller

netlink: fix splat in skb_clone with large messages

2013-06-28T05:44:16+00:00

Since (c05cdb1 netlink: allow large data transfers from user-space),
netlink splats if it invokes skb_clone on large netlink skbs since:

* skb_shared_info was not correctly initialized.
* skb->destructor is not set in the cloned skb.

This was spotted by trinity:

[  894.990671] BUG: unable to handle kernel paging request at ffffc9000047b001
[  894.991034] IP: [] skb_clone+0x24/0xc0
[...]
[  894.991034] Call Trace:
[  894.991034]  [] nl_fib_input+0x6a/0x240
[  894.991034]  [] ? _raw_read_unlock+0x26/0x40
[  894.991034]  [] netlink_unicast+0x169/0x1e0
[  894.991034]  [] netlink_sendmsg+0x251/0x3d0

Fix it by:

1) introducing a new netlink_skb_clone function that is used in nl_fib_input,
   that sets our special skb->destructor in the cloned skb. Moreover, handle
   the release of the large cloned skb head area in the destructor path.

2) not allowing large skbuffs in the netlink broadcast path. I cannot find
   any reasonable use of the large data transfer using netlink in that path,
   moreover this helps to skip extra skb_clone handling.

I found two more netlink clients that are cloning the skbs, but they are
not in the sendmsg path. Therefore, the sole client cloning that I found
seems to be the fib frontend.

Thanks to Eric Dumazet for helping to address this issue.

Reported-by: Fengguang Wu 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: David S. Miller

net: netlink: virtual tap device management

2013-06-24T23:39:05+00:00

Similarly to the networking receive path with ptype_all taps, we add
the possibility to register netdevices that are for ARPHRD_NETLINK to
the netlink subsystem, so that those can be used for netlink analyzers
resp. debuggers. We do not offer a direct callback function as out-of-tree
modules could do crap with it. Instead, a netdevice must be registered
properly and only receives a clone, managed by the netlink layer. Symbols
are exported as GPL-only.

Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

netlink: Add compare function for netlink_table

2013-06-11T09:39:42+00:00

As we know, netlink sockets are private resource of
net namespace, they can communicate with each other
only when they in the same net namespace. this works
well until we try to add namespace support for other
subsystems which use netlink.

Don't like ipv4 and route table.., it is not suited to
make these subsytems belong to net namespace, Such as
audit and crypto subsystems,they are more suitable to
user namespace.

So we must have the ability to make the netlink sockets
in same user namespace can communicate with each other.

This patch adds a new function pointer "compare" for
netlink_table, we can decide if the netlink sockets can
communicate with each other through this netlink_table
self-defined compare function.

The behavior isn't changed if we don't provide the compare
function for netlink_table.

Signed-off-by: Gao feng 
Acked-by: Serge E. Hallyn 
Signed-off-by: David S. Miller

netlink: implement memory mapped recvmsg()

2013-04-19T18:57:58+00:00

Add support for mmap'ed recvmsg(). To allow the kernel to construct messages
into the mapped area, a dataless skb is allocated and the data pointer is
set to point into the ring frame. This means frames will be delivered to
userspace in order of allocation instead of order of transmission. This
usually doesn't matter since the order is either not determinable by
userspace or message creation/transmission is serialized. The only case
where this can have a visible difference is nfnetlink_queue. Userspace
can't assume mmap'ed messages have ordered IDs anymore and needs to check
this if using batched verdicts.

For non-mapped sockets, nothing changes.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

netlink: add mmap'ed netlink helper functions

2013-04-19T18:57:57+00:00

Add helper functions for looking up mmap'ed frame headers, reading and
writing their status, allocating skbs with mmap'ed data areas and a poll
function.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

netlink: rename ssk to sk in struct netlink_skb_params

2013-04-19T18:57:56+00:00

Memory mapped netlink needs to store the receiving userspace socket
when sending from the kernel to userspace. Rename 'ssk' to 'sk' to
avoid confusion.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

UAPI: (Scripted) Disintegrate include/linux

2012-10-13T09:46:48+00:00

Signed-off-by: David Howells 
Acked-by: Arnd Bergmann 
Acked-by: Thomas Gleixner 
Acked-by: Michael Kerrisk 
Acked-by: Paul E. McKenney 
Acked-by: Dave Jones

netlink: add reference of module in netlink_dump_start

2012-10-07T04:30:56+00:00

I get a panic when I use ss -a and rmmod inet_diag at the
same time.

It's because netlink_dump uses inet_diag_dump which belongs to module
inet_diag.

I search the codes and find many modules have the same problem.  We
need to add a reference to the module which the cb->dump belongs to.

Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo.

Change From v3:
change netlink_dump_start to inline,suggestion from Pablo and
Eric.

Change From v2:
delete netlink_dump_done,and call module_put in netlink_dump
and netlink_sock_destruct.

Signed-off-by: Gao feng 
Signed-off-by: David S. Miller

netlink: Rearrange netlink_kernel_cfg to save space on 64-bit.

2012-09-23T06:09:23+00:00

Suggested by Jan Engelhardt.

Signed-off-by: David S. Miller