linux.git/net/tipc/addr.h, branch v4.12

tipc: introduce constants for tipc address validation

2016-07-26T21:26:42+00:00

In this commit, we introduce defines for tipc address size,
offset and mask specification for Zone.Cluster.Node.
There is no functional change in this commit.

Reviewed-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: add neighbor monitoring framework

2016-06-15T21:06:28+00:00

TIPC based clusters are by default set up with full-mesh link
connectivity between all nodes. Those links are expected to provide
a short failure detection time, by default set to 1500 ms. Because
of this, the background load for neighbor monitoring in an N-node
cluster increases with a factor N on each node, while the overall
monitoring traffic through the network infrastructure increases at
a ~(N * (N - 1)) rate. Experience has shown that such clusters don't
scale well beyond ~100 nodes unless we significantly increase failure
discovery tolerance.

This commit introduces a framework and an algorithm that drastically
reduces this background load, while basically maintaining the original
failure detection times across the whole cluster. Using this algorithm,
background load will now grow at a rate of ~(2 * sqrt(N)) per node, and
at ~(2 * N * sqrt(N)) in traffic overhead. As an example, each node will
now have to actively monitor 38 neighbors in a 400-node cluster, instead
of as before 399.

This "Overlapping Ring Supervision Algorithm" is completely distributed
and employs no centralized or coordinated state. It goes as follows:

- Each node makes up a linearly ascending, circular list of all its N
  known neighbors, based on their TIPC node identity. This algorithm
  must be the same on all nodes.

- The node then selects the next M = sqrt(N) - 1 nodes downstream from
  itself in the list, and chooses to actively monitor those. This is
  called its "local monitoring domain".

- It creates a domain record describing the monitoring domain, and
  piggy-backs this in the data area of all neighbor monitoring messages
  (LINK_PROTOCOL/STATE) leaving that node. This means that all nodes in
  the cluster eventually (default within 400 ms) will learn about
  its monitoring domain.

- Whenever a node discovers a change in its local domain, e.g., a node
  has been added or has gone down, it creates and sends out a new
  version of its node record to inform all neighbors about the change.

- A node receiving a domain record from anybody outside its local domain
  matches this against its own list (which may not look the same), and
  chooses to not actively monitor those members of the received domain
  record that are also present in its own list. Instead, it relies on
  indications from the direct monitoring nodes if an indirectly
  monitored node has gone up or down. If a node is indicated lost, the
  receiving node temporarily activates its own direct monitoring towards
  that node in order to confirm, or not, that it is actually gone.

- Since each node is actively monitoring sqrt(N) downstream neighbors,
  each node is also actively monitored by the same number of upstream
  neighbors. This means that all non-direct monitoring nodes normally
  will receive sqrt(N) indications that a node is gone.

- A major drawback with ring monitoring is how it handles failures that
  cause massive network partitionings. If both a lost node and all its
  direct monitoring neighbors are inside the lost partition, the nodes in
  the remaining partition will never receive indications about the loss.
  To overcome this, each node also chooses to actively monitor some
  nodes outside its local domain. Those nodes are called remote domain
  "heads", and are selected in such a way that no node in the cluster
  will be more than two direct monitoring hops away. Because of this,
  each node, apart from monitoring the member of its local domain, will
  also typically monitor sqrt(N) remote head nodes.

- As an optimization, local list status, domain status and domain
  records are marked with a generation number. This saves senders from
  unnecessarily conveying  unaltered domain records, and receivers from
  performing unneeded re-adaptations of their node monitoring list, such
  as re-assigning domain heads.

- As a measure of caution we have added the possibility to disable the
  new algorithm through configuration. We do this by keeping a threshold
  value for the cluster size; a cluster that grows beyond this value
  will switch from full-mesh to ring monitoring, and vice versa when
  it shrinks below the value. This means that if the threshold is set to
  a value larger than any anticipated cluster size (default size is 32)
  the new algorithm is effectively disabled. A patch set for altering the
  threshold value and for listing the table contents will follow shortly.

- This change is fully backwards compatible.

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

tipc: simplify include dependencies

2015-05-14T16:24:45+00:00

When we try to add new inline functions in the code, we sometimes
run into circular include dependencies.

The main problem is that the file core.h, which really should be at
the root of the dependency chain, instead is a leaf. I.e., core.h
includes a number of header files that themselves should be allowed
to include core.h. In reality this is unnecessary, because core.h does
not need to know the full signature of any of the structs it refers to,
only their type declaration.

In this commit, we remove all dependencies from core.h towards any
other tipc header file.

As a consequence of this change, we can now move the function
tipc_own_addr(net) from addr.c to addr.h, and make it inline.

There are no functional changes in this commit.

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

tipc: fix two bugs in secondary destination lookup

2015-03-29T20:47:36+00:00

A message sent to a node after a successful name table lookup may still
find that the destination socket has disappeared, because distribution
of name table updates is non-atomic. If so, the message will be rejected
back to the sender with error code TIPC_ERR_NO_PORT. If the source
socket of the message has disappeared in the meantime, the message
should be dropped.

However, in the currrent code, the message will instead be subject to an
unwanted tertiary lookup, because the function tipc_msg_lookup_dest()
doesn't check if there is an error code present in the message before
performing the lookup. In the worst case, the message may now find the
old destination again, and be redirected once more, instead of being
dropped directly as it should be.

A second bug in this function is that the "prev_node" field in the message
is not updated after successful lookup, something that may have
unpredictable consequences.

The problems arising from those bugs occur very infrequently.

The third change in this function; the test on msg_reroute_msg_cnt() is
purely cosmetic, reflecting that the returned value never can be negative.

This commit corrects the two bugs described above.

Signed-off-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: make tipc node address support net namespace

2015-01-12T21:24:33+00:00

If net namespace is supported in tipc, each namespace will be treated
as a separate tipc node. Therefore, every namespace must own its
private tipc node address. This means the "tipc_own_addr" global
variable of node address must be moved to tipc_net structure to
satisfy the requirement. It's turned out that users also can assign
node address for every namespace.

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

tipc: make tipc broadcast link support net namespace

2015-01-12T21:24:33+00:00

TIPC broadcast link is statically established and its relevant states
are maintained with the global variables: "bcbearer", "bclink" and
"bcl". Allowing different namespace to own different broadcast link
instances, these variables must be moved to tipc_net structure and
broadcast link instances would be allocated and initialized when
namespace is created.

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

tipc: make tipc node table aware of net namespace

2015-01-12T21:24:32+00:00

Global variables associated with node table are below:
- node table list (node_htable)
- node hash table list (tipc_node_list)
- node table lock (node_list_lock)
- node number counter (tipc_num_nodes)
- node link number counter (tipc_num_links)

To make node table support namespace, above global variables must be
moved to tipc_net structure in order to keep secret for different
namespaces. As a consequence, these variables are allocated and
initialized when namespace is created, and deallocated when namespace
is destroyed. After the change, functions associated with these
variables have to utilize a namespace pointer to access them. So
adding namespace pointer as a parameter of these functions is the
major change made in the commit.

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

tipc: cleanup core.c and core.h files

2015-01-12T21:24:31+00:00

Only the works of initializing and shutting down tipc module are done
in core.h and core.c files, so all stuffs which are not closely
associated with the two tasks should be moved to appropriate places.

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

tipc: explicitly include core.h in addr.h

2014-02-13T22:49:13+00:00

The inline functions in addr.h uses tipc_own_addr which is exported by
core.h, but addr.h never actually includes it. It works because it is
explicitly included where this is used, but it looks a bit strange.

Include core.h in addr.h explicitly to make the dependency clearer.

Signed-off-by: Andreas Bofjäll 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: compress out gratuitous extra carriage returns

2012-04-30T19:53:56+00:00

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: Paul Gortmaker