With this commit series we introduce a 'Group Communication' feature in
order to resolve the datagram and multicast flow control problem. This
new feature makes it possible to instantiate multiple virtual brokerless
message buses by just creating member sockets.
The main features are as follows:
---------------------------------
- Sockets can join a group via a new setsockopt() call TIPC_GROUP_JOIN.
If it is the first socket of the group this implies creation of the
group. This call takes four parameters: 'type' serves as group
identifier, 'instance' serves as member identifier, and 'scope'
indicates the visibility of the group (node/cluster/zone). Finally,
'flags' indicates different options for the socket joining the group.
For the time being, there are only two such flags: 1) 'LOOPBACK'
indicates if the creator of the socket wants to receive a copy of
broadcast or multicast messages it sends to the group, 2) EVENTS
indicates if it wants to receive membership (JOINED/LEFT) events for
the other members of the group.
- Groups are closed, i.e., sockets which have not joined a group will
not be able to send messages to or receive messages from members of
the group, and vice versa. A socket can only be member of one group
at a time.
- There are four transmission modes.
1: Unicast. The sender transmits a message using the port identity
(node:port tuple) of the receiving socket.
2: Anycast. The sender transmits a message using a port name (type:
instance:scope) of one of the receiving sockets. If more than
one member socket matches the given address a destination is
selected according to a round-robin algorithm, but also considering
the destination load (advertised window size) as an additional
criteria.
3: Multicast. The sender transmits a message using a port name
(type:instance:scope) of one or more of the receiving sockets.
All sockets in the group matching the given address will receive
a copy of the message.
4: Broadcast. The sender transmits a message using the primtive
send(). All members of the group, irrespective of their member
identity (instance) number receive a copy of the message.
- TIPC broadcast is used for carrying messages in mode 3 or 4 when
this is deemed more efficient, i.e., depending on number of actual
destinations.
- All transmission modes are flow controlled, so that messages never
are dropped or rejected, just like we are used to from connection
oriented communication. A special algorithm guarantees that this is
true even for multipoint-to-point communication, i.e., at occasions
where many source sockets may decide to send simultaneously towards
the same destination socket.
- Sequence order is always guaranteed, even between the different
transmission modes.
- Member join/leave events are received in all other member sockets
in guaranteed order. I.e., a 'JOINED' (an empty message with the OOB
bit set) will always be received before the first data message from
a new member, and a 'LEAVE' (like 'JOINED', but with EOR bit set) will
always arrive after the last data message from a leaving member.
Jon Maloy (18):
tipc: add ability to order and receive topology events in driver
tipc: improve address sanity check in tipc_connect()
tipc: add ability to obtain node availability status from other files
tipc: refactor function filter_rcv()
tipc: add new function for sending multiple small messages
tipc: improve destination linked list
tipc: introduce communication groups
tipc: add second source address to recvmsg()/recvfrom()
tipc: receive group membership events via member socket
tipc: introduce flow control for group broadcast messages
tipc: introduce group unicast messaging
tipc: introduce group anycast messaging
tipc: introduce group multicast messaging
tipc: guarantee group unicast doesn't bypass group broadcast
tipc: guarantee that group broadcast doesn't bypass group unicast
tipc: guarantee delivery of UP event before first broadcast
tipc: guarantee delivery of last broadcast before DOWN event
tipc: add multipoint-to-point flow control
include/uapi/linux/tipc.h | 15 +
net/tipc/Makefile | 2 +-
net/tipc/bcast.c | 18 +-
net/tipc/core.h | 5 +
net/tipc/group.c | 874 ++++++++++++++++++++++++++++++++++++++++++++++
net/tipc/group.h | 73 ++++
net/tipc/link.c | 9 +-
net/tipc/msg.c | 7 +
net/tipc/msg.h | 110 +++++-
net/tipc/name_table.c | 174 ++++++---
net/tipc/name_table.h | 28 +-
net/tipc/node.c | 42 ++-
net/tipc/node.h | 5 +-
net/tipc/server.c | 121 +++++--
net/tipc/server.h | 5 +-
net/tipc/socket.c | 770 +++++++++++++++++++++++++++++++---------
16 files changed, 1988 insertions(+), 270 deletions(-)
create mode 100644 net/tipc/group.c
create mode 100644 net/tipc/group.h
--
2.1.4
