linux/net/tipc/node.h, branch v5.4

tipc: optimize link synching mechanism

2019-07-25T22:55:47Z

This commit along with the next one are to resolve the issues with the link changeover mechanism. See that commit for details. Basically, for the link synching, from now on, we will send only one single ("dummy") SYNCH message to peer. The SYNCH message does not contain any data, just a header conveying the synch point to the peer. A new node capability flag ("TIPC_TUNNEL_ENHANCED") is introduced for backward compatible! Acked-by: Ying Xue Acked-by: Jon Maloy Suggested-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: improve TIPC throughput by Gap ACK blocks

2019-04-05T01:29:25Z

During unicast link transmission, it's observed very often that because of one or a few lost/dis-ordered packets, the sending side will fastly reach the send window limit and must wait for the packets to be arrived at the receiving side or in the worst case, a retransmission must be done first. The sending side cannot release a lot of subsequent packets in its transmq even though all of them might have already been received by the receiving side. That is, one or two packets dis-ordered/lost and dozens of packets have to wait, this obviously reduces the overall throughput! This commit introduces an algorithm to overcome this by using "Gap ACK blocks". Basically, a Gap ACK block will consist of numbers that describes the link deferdq where packets have been got by the receiving side but with gaps, for example: link deferdq: [1 2 3 4 10 11 13 14 15 20] --> Gap ACK blocks: <4, 5>, <11, 1>, <15, 4>, <20, 0> The Gap ACK blocks will be sent to the sending side along with the traditional ACK or NACK message. Immediately when receiving the message the sending side will now not only release from its transmq the packets ack-ed by the ACK but also by the Gap ACK blocks! So, more packets can be enqueued and transmitted. In addition, the sending side can now do "multi-retransmissions" according to the Gaps reported in the Gap ACK blocks. The new algorithm as verified helps greatly improve the TIPC throughput especially under packet loss condition. So far, a maximum of 32 blocks is quite enough without any "Too few Gap ACK blocks" reports with a 5.0% packet loss rate, however this number can be increased in the furture if needed. Also, the patch is backward compatible. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: introduce new capability flag for cluster

2019-03-19T20:56:17Z

As a preparation for introducing a smooth switching between replicast and broadcast method for multicast message, We have to introduce a new capability flag TIPC_MCAST_RBCTL to handle this new feature. During a cluster upgrade a node can come back with this new capabilities which also must be reflected in the cluster capabilities field. The new feature is only applicable if all node in the cluster supports this new capability. Acked-by: Jon Maloy Signed-off-by: Hoang Le Signed-off-by: David S. Miller

tipc: enable tracepoints in tipc

2018-12-19T19:49:24Z

As for the sake of debugging/tracing, the commit enables tracepoints in TIPC along with some general trace_events as shown below. It also defines some 'tipc_*_dump()' functions that allow to dump TIPC object data whenever needed, that is, for general debug purposes, ie. not just for the trace_events. The following trace_events are now available: - trace_tipc_skb_dump(): allows to trace and dump TIPC msg & skb data, e.g. message type, user, droppable, skb truesize, cloned skb, etc. - trace_tipc_list_dump(): allows to trace and dump any TIPC buffers or queues, e.g. TIPC link transmq, socket receive queue, etc. - trace_tipc_sk_dump(): allows to trace and dump TIPC socket data, e.g. sk state, sk type, connection type, rmem_alloc, socket queues, etc. - trace_tipc_link_dump(): allows to trace and dump TIPC link data, e.g. link state, silent_intv_cnt, gap, bc_gap, link queues, etc. - trace_tipc_node_dump(): allows to trace and dump TIPC node data, e.g. node state, active links, capabilities, link entries, etc. How to use: Put the trace functions at any places where we want to dump TIPC data or events. Note: a) The dump functions will generate raw data only, that is, to offload the trace event's processing, it can require a tool or script to parse the data but this should be simple. b) The trace_tipc_*_dump() should be reserved for a failure cases only (e.g. the retransmission failure case) or where we do not expect to happen too often, then we can consider enabling these events by default since they will almost not take any effects under normal conditions, but once the rare condition or failure occurs, we get the dumped data fully for post-analysis. For other trace purposes, we can reuse these trace classes as template but different events. c) A trace_event is only effective when we enable it. To enable the TIPC trace_events, echo 1 to 'enable' files in the events/tipc/ directory in the 'debugfs' file system. Normally, they are located at: /sys/kernel/debug/tracing/events/tipc/ For example: To enable the tipc_link_dump event: echo 1 > /sys/kernel/debug/tracing/events/tipc/tipc_link_dump/enable To enable all the TIPC trace_events: echo 1 > /sys/kernel/debug/tracing/events/tipc/enable To collect the trace data: cat trace or cat trace_pipe > /trace.out & To disable all the TIPC trace_events: echo 0 > /sys/kernel/debug/tracing/events/tipc/enable To clear the trace buffer: echo > trace d) Like the other trace_events, the feature like 'filter' or 'trigger' is also usable for the tipc trace_events. For more details, have a look at: Documentation/trace/ftrace.txt MAINTAINERS | add two new files 'trace.h' & 'trace.c' in tipc Acked-by: Ying Xue Tested-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: add SYN bit to connection setup messages

2018-09-29T18:24:22Z

Messages intended for intitating a connection are currently indistinguishable from regular datagram messages. The TIPC protocol specification defines bit 17 in word 0 as a SYN bit to allow sanity check of such messages in the listening socket, but this has so far never been implemented. We do that in this commit. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add sequence number check for link STATE messages

2018-07-12T06:06:14Z

Some switch infrastructures produce huge amounts of packet duplicates. This becomes a problem if those messages are STATE/NACK protocol messages, causing unnecessary retransmissions of already accepted packets. We now introduce a unique sequence number per STATE protocol message so that duplicates can be identified and ignored. This will also be useful when tracing such cases, and to avert replay attacks when TIPC is encrypted. For compatibility reasons we have to introduce a new capability flag TIPC_LINK_PROTO_SEQNO to handle this new feature. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: introduce ioctl for fetching node identity

2018-04-27T15:05:41Z

After the introduction of a 128-bit node identity it may be difficult for a user to correlate between this identity and the generated node hash address. We now try to make this easier by introducing a new ioctl() call for fetching a node identity by using the hash value as key. This will be particularly useful when we extend some of the commands in the 'tipc' tool, but we also expect regular user applications to need this feature. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: confgiure and apply UDP bearer MTU on running links

2018-04-20T15:04:05Z

Currently, we have option to configure MTU of UDP media. The configured MTU takes effect on the links going up after that moment. I.e, a user has to reset bearer to have new value applied across its links. This is confusing and disturbing on a running cluster. We now introduce the functionality to change the default UDP bearer MTU in struct tipc_bearer. Additionally, the links are updated dynamically, without any need for a reset, when bearer value is changed. We leverage the existing per-link functionality and the design being symetrical to the confguration of link tolerance. Acked-by: Jon Maloy Signed-off-by: GhantaKrishnamurthy MohanKrishna Signed-off-by: David S. Miller

tipc: handle collisions of 32-bit node address hash values

2018-03-23T17:12:18Z

When a 32-bit node address is generated from a 128-bit identifier, there is a risk of collisions which must be discovered and handled. We do this as follows: - We don't apply the generated address immediately to the node, but do instead initiate a 1 sec trial period to allow other cluster members to discover and handle such collisions. - During the trial period the node periodically sends out a new type of message, DSC_TRIAL_MSG, using broadcast or emulated broadcast, to all the other nodes in the cluster. - When a node is receiving such a message, it must check that the presented 32-bit identifier either is unused, or was used by the very same peer in a previous session. In both cases it accepts the request by not responding to it. - If it finds that the same node has been up before using a different address, it responds with a DSC_TRIAL_FAIL_MSG containing that address. - If it finds that the address has already been taken by some other node, it generates a new, unused address and returns it to the requester. - During the trial period the requesting node must always be prepared to accept a failure message, i.e., a message where a peer suggests a different (or equal) address to the one tried. In those cases it must apply the suggested value as trial address and restart the trial period. This algorithm ensures that in the vast majority of cases a node will have the same address before and after a reboot. If a legacy user configures the address explicitly, there will be no trial period and messages, so this protocol addition is completely backwards compatible. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add 128-bit node identifier

2018-03-23T17:12:18Z

We add a 128-bit node identity, as an alternative to the currently used 32-bit node address. For the sake of compatibility and to minimize message header changes we retain the existing 32-bit address field. When not set explicitly by the user, this field will be filled with a hash value generated from the much longer node identity, and be used as a shorthand value for the latter. We permit either the address or the identity to be set by configuration, but not both, so when the address value is set by a legacy user the corresponding 128-bit node identity is generated based on the that value. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller