Commit Graph

5 Commits

Author SHA1 Message Date
Evgeniy Polyakov 897522ea1c [CONNECTOR]: Add userspace example code into Documentation/connector/
I was asked several times to include userspace example code into
Documentation, so if there is no policy against it, consider attached patch
for 2.6.18. This program works with included Documentation/connector/cn_test.c
connector module.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 18:42:00 -07:00
Evgeniy Polyakov b191ba0d59 [CONNECTOR]: Use netlink_has_listeners() to avoind unnecessary allocations.
Return -ESRCH from cn_netlink_send() when there are not listeners,
just as it could be done by netlink_broadcast().  Propagate
netlink_broadcast() error back to the caller.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:21:40 -08:00
Carlo Comin 18a0c23617 [CONNECTOR]: Fix documentation test module.
Patch from Carlo Comin <vl4d spine-group.org>

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-08 09:38:56 -08:00
Evgeniy Polyakov eb0d604114 [CONNECTOR]: Update documentation to match reality.
Updated documentation to reflect 2.6.14 netlink changes
about socket options, multicasting and group number.
Please concider for 2.6.14.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-13 14:42:04 -07:00
Evgeniy Polyakov 7672d0b544 [NET]: Add netlink connector.
Kernel connector - new userspace <-> kernel space easy to use
communication module which implements easy to use bidirectional
message bus using netlink as it's backend.  Connector was created to
eliminate complex skb handling both in send and receive message bus
direction.

Connector driver adds possibility to connect various agents using as
one of it's backends netlink based network.  One must register
callback and identifier. When driver receives special netlink message
with appropriate identifier, appropriate callback will be called.

From the userspace point of view it's quite straightforward:

	socket();
	bind();
	send();
	recv();

But if kernelspace want to use full power of such connections, driver
writer must create special sockets, must know about struct sk_buff
handling...  Connector allows any kernelspace agents to use netlink
based networking for inter-process communication in a significantly
easier way:

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);

struct cb_id
{
	__u32			idx;
	__u32			val;
};

idx and val are unique identifiers which must be registered in
connector.h for in-kernel usage.  void (*callback) (void *) - is a
callback function which will be called when message with above idx.val
will be received by connector core.

Using connector completely hides low-level transport layer from it's
users.

Connector uses new netlink ability to have many groups in one socket.

[ Incorporating many cleanups and fixes by myself and
  Andrew Morton -DaveM ]

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-11 19:15:07 -07:00