linux-stable.git/net/tipc/core.h, branch v3.18

tipc: add name distributor resiliency queue

2014-09-02T00:51:48+00:00

TIPC name table updates are distributed asynchronously in a cluster,
entailing a risk of certain race conditions. E.g., if two nodes
simultaneously issue conflicting (overlapping) publications, this may
not be detected until both publications have reached a third node, in
which case one of the publications will be silently dropped on that
node. Hence, we end up with an inconsistent name table.

In most cases this conflict is just a temporary race, e.g., one
node is issuing a publication under the assumption that a previous,
conflicting, publication has already been withdrawn by the other node.
However, because of the (rtt related) distributed update delay, this
may not yet hold true on all nodes. The symptom of this failure is a
syslog message: "tipc: Cannot publish {%u,%u,%u}, overlap error".

In this commit we add a resiliency queue at the receiving end of
the name table distributor. When insertion of an arriving publication
fails, we retain it in this queue for a short amount of time, assuming
that another update will arrive very soon and clear the conflict. If so
happens, we insert the publication, otherwise we drop it.

The (configurable) retention value defaults to 2000 ms. Knowing from
experience that the situation described above is extremely rare, there
is no risk that the queue will accumulate any large number of items.

Signed-off-by: Erik Hugne 
Signed-off-by: Jon Maloy 
Acked-by: Ying Xue 
Signed-off-by: David S. Miller

tipc: use pseudo message to wake up sockets after link congestion

2014-08-23T18:18:33+00:00

The current link implementation keeps a linked list of blocked ports/
sockets that is populated when there is link congestion. The purpose
of this is to let the link know which users to wake up when the
congestion abates.

This adds unnecessary complexity to the data structure and the code,
since it forces us to involve the link each time we want to delete
a socket. It also forces us to grab the spinlock port_lock within
the scope of node_lock. We want to get rid of this direct dependence,
as well as the deadlock hazard resulting from the usage of port_lock.

In this commit, we instead let the link keep list of a "wakeup" pseudo
messages for use in such situations. Those messages are sent to the
pending sockets via the ordinary message reception path, and wake up
the socket's owner when they are received.

This enables us to get rid of the 'waiting_ports' linked lists in struct
tipc_port that manifest this direct reference. As a consequence, we can
eliminate another BH entry into the socket, and hence the need to grab
port_lock. This is a further step in our effort to remove port_lock
altogether.

Signed-off-by: Jon Maloy 
Reviewed-by: Erik Hugne 
Reviewed-by: Ying Xue 
Signed-off-by: David S. Miller

tipc: improve and extend media address conversion functions

2014-05-14T19:19:48+00:00

TIPC currently handles two media specific addresses: Ethernet MAC
addresses and InfiniBand addresses. Those are kept in three different
formats:

1) A "raw" format as obtained from the device. This format is known
   only by the media specific adapter code in eth_media.c and
   ib_media.c.
2) A "generic" internal format, in the form of struct tipc_media_addr,
   which can be referenced and passed around by the generic media-
   unaware code.
3) A serialized version of the latter, to be conveyed in neighbor
   discovery messages.

Conversion between the three formats can only be done by the media
specific code, so we have function pointers for this purpose in
struct tipc_media. Here, the media adapters can install their own
conversion functions at startup.

We now introduce a new such function, 'raw2addr()', whose purpose
is to convert from format 1 to format 2 above. We also try to as far
as possible uniform commenting, variable names and usage of these
functions, with the purpose of making them more comprehensible.

We can now also remove the function tipc_l2_media_addr_set(), whose
job is done better by the new function.

Finally, we expand the field for serialized addresses (format 3)
in discovery messages from 20 to 32 bytes. This is permitted
according to the spec, and reduces the risk of problems when we
add new media in the future.

Signed-off-by: Jon Maloy 
Reviewed-by: Ying Xue 
Signed-off-by: David S. Miller

tipc: rename and move message reassembly function

2014-05-14T19:19:48+00:00

The function tipc_link_frag_rcv() is in reality a re-entrant generic
message reassemby function that has nothing in particular to do with
the link, where it is defined now. This becomes obvious when we see
the need to call the function from other places in the code.

In this commit rename it to tipc_buf_append() and move it to the file
msg.c. We also simplify its signature by moving the tail pointer to
the control block of the head buffer, hence making the head buffer
self-contained.

Signed-off-by: Jon Maloy 
Reviewed-by: Ying Xue 
Signed-off-by: David S. Miller

tipc: purge signal handler infrastructure

2014-05-05T21:26:45+00:00

In the previous commits of this series, we removed all asynchronous
actions which were based on the tasklet handler - "tipc_k_signal()".

So the moment has now come when we can completely remove the tasklet
handler infrastructure. That is done with this commit.

Signed-off-by: Ying Xue 
Reviewed-by: Erik Hugne 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: replace config_mutex lock with RTNL lock

2014-04-23T01:17:52+00:00

There have two paths where we can configure or change bearer status:
one is that bearer is configured from user space with tipc-config
tool; another one is that bearer is changed by notification events
from its attached interface. On the first path, one dedicated
config_mutex lock is guarded; on the latter path, RTNL lock has been
placed to serialize the process of dealing with interface events.
So, if RTNL lock is also used to protect the first path, this will
not only extremely help us simplify current locking policy, but also
config_mutex lock can be deleted as well.

Signed-off-by: Ying Xue 
Reviewed-by: Jon Maloy 
Reviewed-by: Erik Hugne 
Tested-by: Erik Hugne 
Signed-off-by: David S. Miller

tipc: obsolete the remote management feature

2014-03-27T17:08:36+00:00

Due to the lacking of any credential, it's allowed to accept commands
requested from remote nodes to query the local node status, which is
prone to involve potential security risks. Instead, if we login to
a remote node with ssh command, this approach is not only more safe
than the remote management feature, but also it can give us more
permissions like changing the remote node configuration. So it's
reasonable for us to obsolete the remote management feature now.

Signed-off-by: Ying Xue 
Reviewed-by: Erik Hugne 
Signed-off-by: David S. Miller

tipc: make bearer set up in module insertion stage

2014-02-22T05:00:15+00:00

Accidentally a side effect is involved by commit 6e967adf7(tipc:
relocate common functions from media to bearer). Now tipc stack
handler of receiving packets from netdevices as well as netdevice
notification handler are registered when bearer is enabled rather
than tipc module initialization stage, but the two handlers are
both unregistered in tipc module exit phase. If tipc module is
inserted and then immediately removed, the following warning
message will appear:

"dev_remove_pack: ffffffffa0380940 not found"

This is because in module insertion stage tipc stack packet handler
is not registered at all, but in module exit phase dev_remove_pack()
needs to remove it. Of course, dev_remove_pack() cannot find tipc
protocol handler from the kernel protocol handler list so that the
warning message is printed out.

But if registering the two handlers is adjusted from enabling bearer
phase into inserting module stage, the warning message will be
eliminated. Due to this change, tipc_core_start_net() and
tipc_core_stop_net() can be deleted as well.

Reported-by: Wang Weidong 
Cc: Jon Maloy 
Cc: Erik Hugne 
Signed-off-by: Ying Xue 
Reviewed-by: Paul Gortmaker 
Signed-off-by: David S. Miller

tipc: fix message corruption bug for deferred packets

2014-02-13T21:35:05+00:00

If a packet received on a link is out-of-sequence, it will be
placed on a deferred queue and later reinserted in the receive
path once the preceding packets have been processed. The problem
with this is that it will be subject to the buffer adjustment from
link_recv_buf_validate twice. The second adjustment for 20 bytes
header space will corrupt the packet.

We solve this by tagging the deferred packets and bail out from
receive buffer validation for packets that have already been
subjected to this.

Signed-off-by: Erik Hugne 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: Use instead of

2013-12-16T17:48:35+00:00

As warned by checkpatch.pl, use #include 
instead of 

Reviewed-by: Jon Maloy 
Reviewed-by: Erik Hugne 
Signed-off-by: Wang Weidong 
Signed-off-by: David S. Miller