Commit Graph

453 Commits

Author SHA1 Message Date
Allan Stephens
47361c87c5 tipc: Fix problem with broadcast link synchronization between nodes
Corrects a problem in which a link endpoint that activates as the
result of receiving a RESET/STATE sequence of link protocol messages
fails to properly record the broadcast link status information about
the node to which it is now communicating with. (The problem does
not occur with the more common RESET/ACTIVATE sequence of messages.)
The fix ensures that the broadcast link status info is updated after
the RESET message resets the link endpoint, rather than before, thereby
preventing new information from being overwritten by the reset operation.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:16 -05:00
Allan Stephens
9349931371 tipc: Ensure broadcast link re-acquires node after link failure
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: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:16 -05:00
Allan Stephens
4d75313ce9 tipc: Prevent broadcast link stalling in dual LAN environments
Ensure that sequence number information about incoming broadcast link
messages is initialized only by the activation of the first link to a
given cluster node.  Previously, a race condition allowed reset and/or
activation messages for a second link to re-initialize this sequence
number information with obsolete values. This could trigger TIPC to
request the retransmission of previously acknowledged broadcast link
messages from that node, resulting in broadcast link processing becoming
stalled if the node had already released one or more of those messages
and was unable to perform the required retransmission.

Thanks to Laser <gotolaser@gmail.com> for identifying this problem
and assisting in the development of this fix.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:16 -05:00
Allan Stephens
92d2c905b4 tipc: Prevent transmission of outdated link protocol messages
Ensures that a link endpoint discards any previously deferred link
protocol message whenever it attempts to send a new one.

Previously, it was possible for a link protocol message that was unsent
due to congestion to be transmitted after newer protocol messages had
been sent. The stale link protocol message might then cause the receiving
link endpoint to malfunction because of its outdated conent.

Thanks to Osamu Kaminuma [okaminum@avaya.com] for diagnosing the problem
and contributing a prototype patch.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:15 -05:00
Allan Stephens
8809b255a9 tipc: improve the link deferred queue insertion algorithm
Re-code the algorithm for inserting an out-of-sequence message into
a unicast or broadcast link's deferred message queue.  It remains
functionally equivalent but should be easier to understand/maintain.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:15 -05:00
Paul Gortmaker
f19765f4f7 tipc: rename struct bearer_name to struct tipc_bearer_names
The addition of the "s" to indicate pluralization is intentional,
since the struct actually contains two name variants.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:30 -05:00
Paul Gortmaker
a18c4bc3ea tipc: rename struct link* to struct tipc_link*
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: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:30 -05:00
Paul Gortmaker
7f9ab6ac2e tipc: rename struct bcbearer* to tipc_bcbearer*
This changes both the struct bcbearer and struct bcbearer_pair to
have the "tipc_" prefix.  Runtime behaviour is unchanged.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:30 -05:00
Paul Gortmaker
6765fd6771 tipc: rename struct bclink to struct tipc_bclink
Make this rename so that it is consistent with the majority
of the other tipc structs and to assist in removing any
ambiguity with other similar names in other subsystems.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:30 -05:00
Paul Gortmaker
11f9990604 tipc: rename struct subscriber to struct tipc_subscriber
Make this rename so that it is consistent with the majority
of the other tipc structs and to assist in removing any
ambiguity with other similar names in other subsystems.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:30 -05:00
Paul Gortmaker
fead39098b tipc: rename struct subscription to struct tipc_subscription
Make this rename so that it is consistent with the majority
of the other tipc structs and to assist in removing any
ambiguity with other similar names in other subsystems.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:29 -05:00
Paul Gortmaker
4584310b4a tipc: rename struct port_list to struct tipc_port_list
Make this rename so that it is consistent with the majority
of the other tipc structs and to assist in removing any
ambiguity with other similar names in other subsystems.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:29 -05:00
Paul Gortmaker
358a0d1c9e tipc: rename struct media to struct tipc_media
Give it a meaningful prefix, as suggested by DaveM, so that it
is consistent with things like struct tipc_bearer, and so it isn't
confused with anything else.  This has no impact on the actual
runtime code behaviour.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-29 21:53:29 -05:00
Allan Stephens
f905730c7e tipc: Allow use of buf_seqno() helper routine by unicast links
Migrates the buf_seqno() helper routine from broadcast link level to
unicast link level so that it can be used both types of TIPC links.
This is a cosmetic change only, and does not affect the operation of TIPC.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:54 -05:00
Allan Stephens
3655959143 tipc: Ignore broadcast acknowledgements that are out-of-range
Adds checks to TIPC's broadcast link so that it ignores any
acknowledgement message containing a sequence number that does not
correspond to an unacknowledged message currently in the broadcast
link's transmit queue.

This change prevents the broadcast link from becoming stalled if a
newly booted node receives stale broadcast link acknowledgement
information from another node that has not yet fully synchronized
its end of the broadcast link to reflect the current state of the
new node's end.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:53 -05:00
Allan Stephens
10745cd599 tipc: Flush unsent broadcast messages when contact with last node is lost
Adds code to release any unsent broadcast messages in the broadcast link
transmit queue if TIPC loses contact with its only neighboring node.
Previously, a broadcast link that was in the congested state would hold
on to the unsent messages, even though the messages were now undeliverable.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:52 -05:00
Allan Stephens
9157bafb44 tipc: Minor optimization of broadcast link transmit queue statistic
The two broadcast link statistics fields that are used to derive the
average length of that link's transmit queue are now updated only after
a successful attempt to send a broadcast message, since there is no need
to update these values when an unsuccessful send attempt leaves the
queue unchanged.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:51 -05:00
Allan Stephens
2b78f9a002 tipc: Handle broadcast attempt when no neighboring nodes exist
Adds a check to detect when an attempt is made to send a message
via the broadcast link and no neighboring nodes are currently available
to receive it. Rather than wasting effort passing the message to the
broadcast link and broadcast bearer, who will only throw it away,
TIPC now frees the message immediately and reports success (i.e. the
message has been delivered to all available destinations).

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:50 -05:00
Allan Stephens
cd3decdfd1 tipc: Ensure broadcast link spinlock is held when updating node map
Fixes oversight that allowed broadcast link node map to be updated without
first taking the broadcast link spinlock that protects the map. As part
of this fix the node map has been incorporated into the broadcast link
structure to make the need for such protection more evident.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:48 -05:00
Allan Stephens
c47e9b9188 tipc: Eliminate dynamic allocation of broadcast link data structures
Creates global variables to hold the broadcast link's pseudo-bearer and
pseudo-link structures, rather than allocating them dynamically. There
is only a single instance of each structure, and changing over to static
allocation allows elimination of code to handle the cases where dynamic
allocation was unsuccessful.

The memset in the teardown code may look like they aren't used, but
the same teardown code is run when there is a non-fatal error at
init-time, so that stale data isn't present when the user fixes the
cause of the soft error.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:47 -05:00
Allan Stephens
945af1c39d tipc: Eliminate useless check when network address is assigned
Gets rid of an unnecessary check in the routine that updates the port id
of a node's name publications when the node is assigned a network address,
since the routine is only invoked if the new address is different from
the existing one.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:46 -05:00
Allan Stephens
97f1b625d1 tipc: Minor correction to TIPC module unloading
Modifies TIPC's module unloading logic to switch itself into "single
node" mode before starting to terminate networking support. This helps
to ensure that no operations that require TIPC to be in "networking"
mode can initiate once unloading starts.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:45 -05:00
Allan Stephens
d47ce2ece3 tipc: Eliminate useless memset operations in Ethernet media support
Gets rid of two pointless operations that zero out the array used to
record information about TIPC's Ethernet bearers. There is no need to
initialize the array on start up since it is a global variable that is
already zero'd out, and there is no need to zero it out on exit because
the array is never referenced again.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:44 -05:00
Allan Stephens
64b32f7e38 tipc: Do timely cleanup of disabled Ethernet bearer resources
Modifies Ethernet bearer disable logic to break the association between
the bearer and its device driver at the time the bearer is disabled,
rather than when the TIPC module is unloaded. This allows the array
entry used by the disabled bearer to be re-used if the same bearer (or
a different one) is subsequently enabled.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:42 -05:00
Allan Stephens
8c12118db7 tipc: Minor optimization to deactivation of Ethernet media suppot
Change TIPC's shutdown code to deactivate generic networking support
before terminating Ethernet media support. The deactivation of generic
networking support causes all existing bearers to be destroyed, meaning
the Ethernet media termination routine no longer has to bother marking
them as unavailable.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:41 -05:00
Allan Stephens
bfec73d7e4 tipc: Revise comment justifying release of configuration spinlock
Comment-only change to better explain why TIPC's configuration lock is
temporarily released while activating support for network interfaces,
and why the existing activation code doesn't require rework.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:40 -05:00
Allan Stephens
5c216e1d28 tipc: Allow run-time alteration of default link settings
Permits run-time alteration of default link settings on a per-media
and per-bearer basis, in addition to the existing per-link basis.
The following syntax can now be used:

    tipc-config -lt=<link-name|bearer-name|media-name>/<tolerance>
    tipc-config -lp=<link-name|bearer-name|media-name>/<priority>
    tipc-config -lw=<link-name|bearer-name|media-name>/<window>

Note that changes to the default settings for a given media type has
no effect on the default settings used by existing bearers. Similarly,
changes to default bearer settings has no effect on existing link
endpoints that utilize that interface.

Thanks to Florian Westphal <fw@strlen.de> for his contributions to
the development of this enhancement.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:39 -05:00
Allan Stephens
d6d4577ae4 tipc: Ignore neighbor discovery messages containing invalid address
Adds a check to ensure that TIPC ignores an incoming neighbor discovery
message that specifies an invalid media address as its source. The check
ensures that the source address is a valid, non-broadcast address that
could legally be used by a neighboring link endpoint.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:38 -05:00
Allan Stephens
3d749a6a26 tipc: Hide media-specific addressing details from generic bearer code
Reworks TIPC's media address data structure and associated processing
routines to transfer all media-specific details of address conversion
to the associated TIPC media adaptation code. TIPC's generic bearer code
now only needs to know which media type an address is associated with
and whether or not it is a broadcast address, and totally ignores the
"value" field that contains the actual media-specific addressing info.

These changes eliminate the need for a number of endianness conversion
operations and will make it easier for TIPC to support new media types
in the future.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:36 -05:00
Allan Stephens
4d163a326f tipc: Add new address conversion routines for Ethernet media
Enhances TIPC's Ethernet media support to provide 3 new address conversion
routines, which allow TIPC to interpret an address that is in string form
and to convert an address to and from the 20 byte format used in TIPC's
neighbor discovery messages.

These routines are pre-requisites to a follow on commit that hides all
media-specific addressing details from TIPC's generic bearer code.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:33:27 -05:00
Allan Stephens
c61b666e26 tipc: Improve handling of media address printing errors
Enhances conversion of a media address to printable form so that an
unconvertable address will be displayed as a string of hex digits,
rather than not being displayed at all. (Also removes a pointless check
for the existence of the media-specific address conversion routine,
since the routine is not optional.)

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:06 -05:00
Allan Stephens
6c34921010 tipc: Streamline media registration error checking
Simplifies error handling performed during media registration, since
TIPC no longer supports the dynamic addition of new media types that
are potentially error-prone. These simplifications include the following:

1) No longer check for premature registration of a new media type.
2) No longer check for negative link priority values (which was pointless
   since such values are unsigned, and could cause a compiler warning).
3) No longer generate a warning describing the exact cause of any
   registration failure (just warns that overall registration failed).

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:06 -05:00
Allan Stephens
a31abe8dae tipc: Eliminate duplication of media structures
Changes TIPC's list of registered media types from an array of media
structures to an array of pointers to media structures. This eliminates
the need to copy of the contents of the structure passed in during media
registration.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:06 -05:00
Allan Stephens
c79be4549a tipc: Optimize detection of duplicate media registration
Streamlines the detection of an attempt to register a TIPC media structure
using an already registered name or type identifier. The revised logic now
reuses an existing routine to detect an existing name and no longer
unnecessarily manipulates the media type counter during an unsuccessful
registration attempt.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:06 -05:00
Allan Stephens
706767da1b tipc: Register new media using pre-compiled structure
Speeds up the registration of TIPC media types by passing in a structure
containing the required information, rather than by passing in the various
fields describing the media type individually.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:05 -05:00
Allan Stephens
2060a57744 tipc: Enable use by containers having their own network namespace
Permits a Linux container to use TIPC sockets even when it has its own
network namespace defined by removing the check that prohibits such use.
This makes it possible for users who wish to isolate their container
network traffic from normal network traffic to utilize TIPC.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-12-27 11:13:05 -05:00
Eric Dumazet
966567b764 net: two vzalloc() cleanups
We can use vzalloc() helper now instead of __vmalloc() trick

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-19 16:01:38 -05:00
Paul Gortmaker
bc3b2d7fb9 net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules
These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:30 -04:00
Paul Gortmaker
3a9a231d97 net: Fix files explicitly needing to include module.h
With calls to modular infrastructure, these files really
needs the full module.h header.  Call it out so some of the
cleanups of implicit and unrequired includes elsewhere can be
cleaned up.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:28 -04:00
Ying Xue
94362c7e49 tipc: Remove unused link event tracking code
Elimintes prototype link event tracking functionality that has never
been fleshed out and doesn't do anything useful at the current time.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:15 -04:00
Ying Xue
7e2447763c tipc: Remove callback field from subscription structure
Eliminate the "event_cb" member from TIPC's "subscription" structure
since the function pointer it holds always points to subscr_send_event().

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:14 -04:00
Ying Xue
245f3d342d tipc: Simplify prohibition of listen and accept for connectionless sockets
Modifies the proto_ops structure used by TIPC DGRAM and RDM sockets
so that calls to listen() and accept() are handled by existing kernel
"unsupported operation" routines, and eliminates the related checks
in the listen and accept routines used by SEQPACKET and STREAM sockets
that are no longer needed.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:12 -04:00
Ying Xue
1d835874af tipc: Add support for SO_SNDTIMEO socket option
Adds support for the SO_SNDTIMEO socket option. (This complements the
existing support for SO_RCVTIMEO that is already present.)

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:11 -04:00
Allan Stephens
9aa88c2a50 tipc: Enhance sending of bulk name table messages
Modifies the initial transfer of name table entries to a new neighboring
node so that the messages are enqueued as a unit, rather than individually.

The revised algorithm now locates the link carrying the message only once,
and eliminates unnecessary checks for link congestion, message fragmentation,
and message bundling that are not required when sending these messages.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:10 -04:00
Paul Gortmaker
1c553bb52e tipc: relocate/coalesce node cast in tipc_named_node_up
Functions like this are called using unsigned longs from
function pointers.  In this case, the function is passed in
a node which is normally internally treated as a u32 by TIPC.

Rather than add more casts into this function in the future
for each added use of node within, move the cast to a single
place on a local.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:09 -04:00
Allan Stephens
149ce37c8d tipc: Prevent fragmented messages during initial name table exchange
Reduces the maximum size of messages sent during the initial exchange
of name table information between two nodes to be no larger than the
MTU of the first link established between the nodes. This ensures that
messages will never need to be fragmented, which would add unnecessary
overhead to the name table synchronization mechanism.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:08 -04:00
Allan Stephens
909234cdd2 tipc: Lower limits for number of bearers and media types
Reduces the number of bearers a node can support to 2, which can use
identical or non-identical media. This change won't impact users,
since they are currently limited to a maximum of 2 Ethernet bearers,
and will save memory by eliminating a number of unused entries in
TIPC's media and bearer arrays.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:07 -04:00
Allan Stephens
18abf0fb6b tipc: Remove redundant search when enabling bearer
Removes obsolete code that searches for an Ethernet bearer structure entry
to use for a newly enabled bearer, since this search is now performed
at the start of the enabling algorithm.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:06 -04:00
Allan Stephens
bcd326e844 tipc: Fix unsafe device list search when enabling bearer
Ensures that the device list lock is held while trying to locate
the Ethernet device used by a newly enabled bearer, so that the
addition or removal of a device does not cause problems.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:05 -04:00
Allan Stephens
b4b5610223 tipc: Ensure both nodes recognize loss of contact between them
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: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-09-17 22:55:03 -04:00