When a node is created, tipc_net_lock read lock is first held and
then node_create_lock is grabbed in order to prevent the same node
from being created and inserted into both node list and hlist twice.
But when we query node from the two node lists, we only hold
tipc_net_lock read lock without grabbing node_create_lock. Obviously
this locking policy is unable to guarantee that the two node lists
are always synchronized especially when the operation of changing
and accessing them occurs in different contexts like currently doing.

Therefore, rename node_create_lock to node_list_lock to protect the
two node lists, that is, whenever node is inserted into them or node
is queried from them, the node_list_lock should be always held. As a
result, tipc_net_lock read lock becomes redundant and then can be
removed from the node query functions.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Reviewed-by: NErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The flag 'has_redundant_link' is defined only in RESET and ACTIVATE
protocol messages. Due to an ambiguity in the protocol specification it
is currently also transferred in STATE messages. Its value is used to
initialize a link state variable, 'permit_changeover', which is used
to inhibit futile link failover attempts when it is known that the
peer node has no working links at the moment, although the local node
may still think it has one.

The fact that 'has_redundant_link' incorrectly is read from STATE
messages has the effect that 'permit_changeover' sometimes gets a wrong
value, and permanently blocks any links from being re-established. Such
failures can only occur in in dual-link systems, and are extremely rare.
This bug seems to have always been present in the code.

Furthermore, since commit b4b56102
("tipc: Ensure both nodes recognize loss of contact between them"),
the 'permit_changeover' field serves no purpose any more. The task of
enforcing 'lost contact' cycles at both peer endpoints is now taken
by a new mechanism, using the flags WAIT_NODE_DOWN and WAIT_PEER_DOWN
in struct tipc_node to abort unnecessary failover attempts.

We therefore remove the 'has_redundant_link' flag from STATE messages,
as well as the now redundant 'permit_changeover' variable.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Reviewed-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove dead code;
       tipc_bearer_find_interface
       tipc_node_redundant_links

This may break out of tree version of TIPC if there still is one.
But that maybe a good thing :-)
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the first fragment of a long data data message is received on a link, a
reassembly buffer large enough to hold the data from this and all subsequent
fragments of the message is allocated. The payload of each new fragment is
copied into this buffer upon arrival. When the last fragment is received, the
reassembled message is delivered upwards to the port/socket layer.

Not only is this an inefficient approach, but it may also cause bursts of
reassembly failures in low memory situations. since we may fail to allocate
the necessary large buffer in the first place. Furthermore, after 100 subsequent
such failures the link will be reset, something that in reality aggravates the
situation.

To remedy this problem, this patch introduces a different approach. Instead of
allocating a big reassembly buffer, we now append the arriving fragments
to a reassembly chain on the link, and deliver the whole chain up to the
socket layer once the last fragment has been received. This is safe because
the retransmission layer of a TIPC link always delivers packets in strict
uninterrupted order, to the reassembly layer as to all other upper layers.
Hence there can never be more than one fragment chain pending reassembly at
any given time in a link, and we can trust (but still verify) that the
fragments will be chained up in the correct order.
Signed-off-by: NErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename the "supported" flag in bclink structure to "recv_permitted"
to better reflect what it is used for. When this flag is set for a
given node, we are permitted to receive and acknowledge broadcast
messages from that node.  Convert it to a bool at the same time,
since it is not used to store any numerical values.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

The "supportable" flag in bclink structure is a compatibility flag
indicating whether a peer node is capable of receiving TIPC broadcast
messages. However, all TIPC versions since tipc-1.5, and after the
inclusion in the upstream Linux kernel in 2006, support this capability.
It is highly unlikely that anybody is still using such an old
version of TIPC, let alone that they want to mix it with TIPC-2.0
nodes. Therefore, we now remove the "supportable" flag.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Some of the comment blocks are floating in limbo between two
functions, or between blocks of code.  Delete the extra line
feeds between any comment and its associated following block
of code, to be consistent with the majority of the rest of
the kernel.  Also delete trailing newlines at EOF and fix
a couple trivial typos in existing comments.

This is a 100% cosmetic change with no runtime impact.  We get
rid of over 500 lines of non-code, and being blank line deletes,
they won't even show up as noise in git blame.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Relocates information about the size of TIPC's node table index and
its associated hash function, since only node subsystem routines need
to have access to this information.

Note that these changes are essentially cosmetic in nature, and have
no impact on the actual operation of TIPC.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Adds support for the new "node signature" in neighbor discovery messages,
which is a 16 bit identifier chosen randomly when TIPC is initialized.
This field makes it possible for nodes receiving a neighbor discovery
message to detect if multiple neighboring nodes are using the same network
address (i.e. <Z.C.N>), even when the messages are arriving on different
interfaces.

This first phase of node signature support creates the signature,
incorporates it into outgoing neighbor discovery messages, and tracks
the signature used by valid neighbors. An upcoming patch builds on this
foundation to implement the improved duplicate neighbor detection checking.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Eliminates support for the broadcast tag field, which is no longer
used by broadcast link NACK messages.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Completely redesigns broadcast link ACK and NACK mechanisms to prevent
spurious retransmit requests in dual LAN networks, and to prevent the
broadcast link from stalling due to the failure of a receiving node to
acknowledge receiving a broadcast message or request its retransmission.

Note: These changes only impact the timing of when ACK and NACK messages
are sent, and not the basic broadcast link protocol itself, so inter-
operability with nodes using the "classic" algorithms is maintained.

The revised algorithms are as follows:

1) An explicit ACK message is still sent after receiving 16 in-sequence
messages, and implicit ACK information continues to be carried in other
unicast link message headers (including link state messages).  However,
the timing of explicit ACKs is now based on the receiving node's absolute
network address rather than its relative network address to ensure that
the failure of another node does not delay the ACK beyond its 16 message
target.

2) A NACK message is now typically sent only when a message gap persists
for two consecutive incoming link state messages; this ensures that a
suspected gap is not confirmed until both LANs in a dual LAN network have
had an opportunity to deliver the message, thereby preventing spurious NACKs.
A NACK message can also be generated by the arrival of a single link state
message, if the deferred queue is so big that the current message gap
cannot be the result of "normal" mis-ordering due to the use of dual LANs
(or one LAN using a bonded interface). Since link state messages typically
arrive at different nodes at different times the problem of multiple nodes
issuing identical NACKs simultaneously is inherently avoided.

3) Nodes continue to "peek" at NACK messages sent by other nodes. If
another node requests retransmission of a message gap suspected (but not
yet confirmed) by the peeking node, the peeking node forgets about the
gap and does not generate a duplicate retransmit request. (If the peeking
node subsequently fails to receive the lost message, later link state
messages will cause it to rediscover and confirm the gap and send another
NACK.)

4) Message gap "equality" is now determined by the start of the gap only.
This is sufficient to deal with the most common cases of message loss,
and eliminates the need for complex end of gap computations.

5) A peeking node no longer tries to determine whether it should send a
complementary NACK, since the most common cases of message loss don't
require it to be sent. Consequently, the node no longer examines the
"broadcast tag" field of a NACK message when peeking.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Fix a bug that can prevent TIPC from sending broadcast messages to a node
if contact with the node is lost and then regained. The problem occurs if
the broadcast link first clears the flag indicating the node is part of the
link's distribution set (when it loses contact with the node), and later
fails to restore the flag (when contact is regained); restoration fails
if contact with the node is regained by implicit unicast link activation
triggered by the arrival of a data message, rather than explicitly by the
arrival of a link activation message.

The broadcast link now uses separate fields to track whether a node is
theoretically capable of receiving broadcast messages versus whether it is
actually part of the link's distribution set. The former member is updated
by the receipt of link protocol messages, which can occur at any time; the
latter member is updated only when contact with the node is gained or lost.
This change also permits the simplification of several conditional
expressions since the broadcast link's "supported" field can now only be
set if there are working links to the associated node.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

This converts the following:

	struct link		->	struct tipc_link
	struct link_req		->	struct tipc_link_req
	struct link_name	->	struct tipc_link_name
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Enhances TIPC to ensure that a node that loses contact with a
neighboring node does not allow contact to be re-established until
it sees that its peer has also recognized the loss of contact.

Previously, nodes that were connected by two or more links could
encounter a situation in which node A would lose contact with node B
on all of its links, purge its name table of names published by B,
and then fail to repopulate those names once contact with B was restored.
This would happen because B was able to re-establish one or more links
so quickly that it never reached a point where it had no links to A --
meaning that B never saw a loss of contact with A, and consequently
didn't re-publish its names to A.

This problem is now prevented by enhancing the cleanup done by TIPC
following a loss of contact with a neighboring node to ensure that
node A ignores all messages sent by B until it receives a LINK_PROTOCOL
message that indicates B has lost contact with A, thereby preventing
the (re)establishment of links between the nodes. The loss of contact
is recognized when a RESET or ACTIVATE message is received that has
a "redundant link exists" field of 0, indicating that B's sending link
endpoint is in a reset state and that B has no other working links.

Additionally, TIPC now suppresses the sending of (most) link protocol
messages to a neighboring node while it is cleaning up after an earlier
loss of contact with that node. This stops the peer node from prematurely
activating its link endpoint, which would prevent TIPC from later
activating its own end. TIPC still allows outgoing RESET messages to
occur during cleanup, to avoid problems if its own node recognizes
the loss of contact first and tries to notify the peer of the situation.

Finally, TIPC now recognizes an impending loss of contact with a peer node
as soon as it receives a RESET message on a working link that is the
peer's only link to the node, and ensures that the link protocol
suppression mentioned above goes into effect right away -- that is,
even before its own link endpoints have failed. This is necessary to
ensure correct operation when there are redundant links between the nodes,
since otherwise TIPC would send an ACTIVATE message upon receiving a RESET
on its first link and only begin suppressing when a RESET on its second
link was received, instead of initiating suppression with the first RESET
message as it needs to.

Note: The reworked cleanup code also eliminates a check that prevented
a link endpoint's discovery object from responding to incoming messages
while stale name table entries are being purged. This check is now
unnecessary and would have slowed down re-establishment of communication
between the nodes in some situations.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Enhances link creation code as follows:

1) Detects illegal attempts to add a requested link earlier in the
   link creation process. This prevents TIPC from wasting time
   initializing a link object it then throws away, and also eliminates
   the code needed to do the throwing away.

2) Passes in the node object associated with the requested link.
   This allows TIPC to eliminate a search to locate the node object,
   as well as code that attempted to create the node if it doesn't
   exist.
Signed-off-by: NAllan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Function names like "tipc_node_has_redundant_links" are unweildy
and result in long lines even for simple lines.  The "has" doesn't
contribute any value add, so dropping that is a slight step in the
right direction.   This is a cosmetic change, basic result of:

for i in `grep -l tipc_node_has_ *` ; do sed -i s/tipc_node_has_/tipc_node_/ $i ; done
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Replaces the dynamically allocated array of pointers to the cluster's
node objects with a static hash table. Hash collisions are resolved
using chaining, with a typical hash chain having only a single node,
to avoid degrading performance during processing of incoming packets.
The conversion to a hash table reduces the memory requirements for
TIPC's node table to approximately the same size it had prior to
the previous commit.

In addition to the hash table itself, TIPC now also maintains a
linked list for the node objects, sorted by ascending network address.
This list allows TIPC to continue sending responses to user space
applications that request node and link information in sorted order.
The list also improves performance when name table update messages are
sent by making it easier to identify the nodes that must be notified.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Converts the fields of the global "tipc_net" structure into individual
variables.  Since the struct was never referenced as a complete unit,
its existence was pointless.  This will facilitate upcoming changes to
TIPC's node table and simpify upcoming relocation of the variables so
they are only visible to the files that actually use them.

This change is essentially cosmetic in nature, and doesn't affect the
operation of TIPC.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Eliminates routines, data structures, and files that were intended
to allow TIPC to support a network containing multiple clusters.
Currently, TIPC supports only networks consisting of a single cluster
within a single zone, so this code is unnecessary.
Signed-off-by: NAllan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eliminates routines and data structures that were intended to allow
TIPC to route messages to other clusters. Currently, TIPC supports only
networks consisting of a single cluster within a single zone, so this
code is unnecessary.
Signed-off-by: NAllan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eliminates routines, data structures, and files that were intended
to allows TIPC to support a network containing multiple zones.
Currently, TIPC supports only networks consisting of a single cluster
within a single zone, so this code is unnecessary.
Signed-off-by: NAllan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do some cleanups of TIPC based on make namespacecheck
  1. Don't export unused symbols
  2. Eliminate dead code
  3. Make functions and variables local
  4. Rename buf_acquire to tipc_buf_acquire since it is used in several files

Compile tested only.
This make break out of tree kernel modules that depend on TIPC routines.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NJon Maloy <jon.maloy@ericsson.com>
Acked-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ensure that TIPC does not re-establish communication with a
neighboring node until it has finished updating all data structures
containing information about that node to reflect the earlier loss of
contact.  Previously, it was possible for TIPC to perform its purge of
name table entries relating to the node once contact had already been
re-established, resulting in the unwanted removal of valid name table
entries.
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andrew Morton reported a build failure on sparc32, because TIPC
uses names like "struct node" and there is a like named data
structure defined in linux/node.h

This just regexp replaces "struct node*" to "struct tipc_node*"
to avoid this and any future similar problems.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Incorporates several related fixes:
- switchover now occurs when switching from an active link to a standby link
- failure of a standby link no longer initiates switchover
- links now display correct # of received packtes following reactivation
Signed-off-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NPer Liden <per.liden@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Tried to run the new tipc stack through sparse.
Following patch fixes all cases where 0 was used
as replacement of NULL.
Use NULL to document this is a pointer and to silence sparse.

This brough sparse warning count down with 127 to 24 warnings.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NPer Liden <per.liden@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a tipc_ prefix to all externally visible symbols.
Signed-off-by: NPer Liden <per.liden@ericsson.com>

Updated copyright notice to include the year the file was
actually created. Information about file creation dates
was extracted from the files in the old CVS repository
at tipc.sourceforge.net.
Signed-off-by: NPer Liden <per.liden@nospam.ericsson.com>

The copyright statements from different parts of Ericsson
have been merged into one.
Signed-off-by: NPer Liden <per.liden@nospam.ericsson.com>

The license header in each file now more clearly state that this
code is licensed under a dual BSD/GPL. Before this was only
evident if you looked at the MODULE_LICENSE line in core.c.
Signed-off-by: NPer Liden <per.liden@nospam.ericsson.com>

TIPC (Transparent Inter Process Communication) is a protocol designed for
intra cluster communication. For more information see
http://tipc.sourceforge.netSigned-off-by: NPer Liden <per.liden@nospam.ericsson.com>