linux-toradex.git/net/tipc/discover.c, branch v4.1.10

tipc: involve reference counter for node structure

2015-03-29T19:40:28+00:00

TIPC node hash node table is protected with rcu lock on read side.
tipc_node_find() is used to look for a node object with node address
through iterating the hash node table. As the entire process of what
tipc_node_find() traverses the table is guarded with rcu read lock,
it's safe for us. However, when callers use the node object returned
by tipc_node_find(), there is no rcu read lock applied. Therefore,
this is absolutely unsafe for callers of tipc_node_find().

Now we introduce a reference counter for node structure. Before
tipc_node_find() returns node object to its caller, it first increases
the reference counter. Accordingly, after its caller used it up,
it decreases the counter again. This can prevent a node being used by
one thread from being freed by another thread.

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

tipc: add framework for node capabilities exchange

2015-03-14T18:38:32+00:00

The TIPC protocol spec has defined a 13 bit capability bitmap in
the neighbor discovery header, as a means to maintain compatibility
between different code and protocol generations. Until now this field
has been unused.

We now introduce the basic framework for exchanging capabilities
between nodes at first contact. After exchange, a peer node's
capabilities are stored as a 16 bit bitmap in struct tipc_node.

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

tipc: increase size of tipc discovery messages

2015-03-06T03:08:42+00:00

The payload area following the TIPC discovery message header is an
opaque area defined by the media. INT_H_SIZE was enough for
Ethernet/IB/IPv4 but needs to be expanded to carry IPv6 addressing
information.

Signed-off-by: Erik Hugne 
Signed-off-by: David S. Miller

tipc: reduce usage of context info in socket and link

2015-02-06T00:00:01+00:00

The most common usage of namespace information is when we fetch the
own node addess from the net structure. This leads to a lot of
passing around of a parameter of type 'struct net *' between
functions just to make them able to obtain this address.

However, in many cases this is unnecessary. The own node address
is readily available as a member of both struct tipc_sock and
tipc_link, and can be fetched from there instead.
The fact that the vast majority of functions in socket.c and link.c
anyway are maintaining a pointer to their respective base structures
makes this option even more compelling.

In this commit, we introduce the inline functions tsk_own_node()
and link_own_node() to make it easy for functions to fetch the node
address from those structs instead of having to pass along and
dereference the namespace struct.

In particular, we make calls to the msg_xx() functions in msg.{h,c}
context independent by directly passing them the own node address
as parameter when needed. Those functions should be regarded as
leaves in the code dependency tree, and it is hence desirable to
keep them namspace unaware.

Apart from a potential positive effect on cache behavior, these
changes make it easier to introduce the changes that will follow
later in this series.

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

tipc: eliminate race during node creation

2015-02-05T00:09:31+00:00

Instances of struct node are created in the function tipc_disc_rcv()
under the assumption that there is no race between received discovery
messages arriving from the same node. This assumption is wrong.
When we use more than one bearer, it is possible that discovery
messages from the same node arrive at the same moment, resulting in
creation of two instances of struct tipc_node. This may later cause
confusion during link establishment, and may result in one of the links
never becoming activated.

We fix this by making lookup and potential creation of nodes atomic.
Instead of first looking up the node, and in case of failure, create it,
we now start with looking up the node inside node_link_create(), and
return a reference to that one if found. Otherwise, we go ahead and
create the node as we did before.

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

tipc: make tipc random value aware of net namespace

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

After namespace is supported, each namespace should own its private
random value. So the global variable representing the random value
must be moved to tipc_net structure.

Signed-off-by: Ying Xue 
Tested-by: Tero Aho 
Reviewed-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 bearer list support net namespace

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

Bearer list defined as a global variable is used to store bearer
instances. When tipc supports net namespace, bearers created in
one namespace must be isolated with others allocated in other
namespaces, which requires us that the bearer list(bearer_list)
must be moved to tipc_net structure. As a result, a net namespace
pointer has to be passed to functions which access the bearer list.

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: involve namespace infrastructure

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

Involve namespace infrastructure, make the "tipc_net_id" global
variable aware of per namespace, and rename it to "net_id". In
order that the conversion can be successfully done, an instance
of networking namespace must be passed to relevant functions,
allowing them to access the "net_id" variable of per namespace.

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