linux/net/tipc/node.c, branch v4.11

tipc: move premature initilalization of stack variables

2017-02-24T16:42:54Z

In the function tipc_rcv() we initialize a couple of stack variables from the message header before that same header has been validated. In rare cases when the arriving header is non-linar, the validation function itself may linearize the buffer by calling skb_may_pull(), while the wrongly initialized stack fields are not updated accordingly. We fix this in this commit. Reported-by: Matthew Wong Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2017-01-28T15:33:06Z

Two trivial overlapping changes conflicts in MPLS and mlx5. Signed-off-by: David S. Miller

tipc: fix nametbl_lock soft lockup at node/link events

2017-01-24T21:14:57Z

We trigger a soft lockup as we grab nametbl_lock twice if the node has a pending node up/down or link up/down event while: - we process an incoming named message in tipc_named_rcv() and perform an tipc_update_nametbl(). - we have pending backlog items in the name distributor queue during a nametable update using tipc_nametbl_publish() or tipc_nametbl_withdraw(). The following are the call chain associated: tipc_named_rcv() Grabs nametbl_lock tipc_update_nametbl() (publish/withdraw) tipc_node_subscribe()/unsubscribe() tipc_node_write_unlock() << lockup occurs if an outstanding node/link event exits, as we grabs nametbl_lock again >> tipc_nametbl_withdraw() Grab nametbl_lock tipc_named_process_backlog() tipc_update_nametbl() << rest as above >> The function tipc_node_write_unlock(), in addition to releasing the lock processes the outstanding node/link up/down events. To do this, we need to grab the nametbl_lock again leading to the lockup. In this commit we fix the soft lockup by introducing a fast variant of node_unlock(), where we just release the lock. We adapt the node_subscribe()/node_unsubscribe() to use the fast variants. Reported-and-Tested-by: John Thompson Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Parthasarathy Bhuvaragan Signed-off-by: David S. Miller

tipc: introduce replicast as transport option for multicast

2017-01-20T17:10:17Z

TIPC multicast messages are currently carried over a reliable 'broadcast link', making use of the underlying media's ability to transport packets as L2 broadcast or IP multicast to all nodes in the cluster. When the used bearer is lacking that ability, we can instead emulate the broadcast service by replicating and sending the packets over as many unicast links as needed to reach all identified destinations. We now introduce a new TIPC link-level 'replicast' service that does this. Reviewed-by: Parthasarathy Bhuvaragan Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: reduce risk of user starvation during link congestion

2017-01-03T16:13:05Z

The socket code currently handles link congestion by either blocking and trying to send again when the congestion has abated, or just returning to the user with -EAGAIN and let him re-try later. This mechanism is prone to starvation, because the wakeup algorithm is non-atomic. During the time the link issues a wakeup signal, until the socket wakes up and re-attempts sending, other senders may have come in between and occupied the free buffer space in the link. This in turn may lead to a socket having to make many send attempts before it is successful. In extremely loaded systems we have observed latency times of several seconds before a low-priority socket is able to send out a message. In this commit, we simplify this mechanism and reduce the risk of the described scenario happening. When a message is attempted sent via a congested link, we now let it be added to the link's backlog queue anyway, thus permitting an oversubscription of one message per source socket. We still create a wakeup item and return an error code, hence instructing the sender to block or stop sending. Only when enough space has been freed up in the link's backlog queue do we issue a wakeup event that allows the sender to continue with the next message, if any. The fact that a socket now can consider a message sent even when the link returns a congestion code means that the sending socket code can be simplified. Also, since this is a good opportunity to get rid of the obsolete 'mtu change' condition in the three socket send functions, we now choose to refactor those functions completely. Signed-off-by: Parthasarathy Bhuvaragan Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix broadcast link synchronization problem

2016-10-29T21:21:09Z

In commit 2d18ac4ba745 ("tipc: extend broadcast link initialization criteria") we tried to fix a problem with the initial synchronization of broadcast link acknowledge values. Unfortunately that solution is not sufficient to solve the issue. We have seen it happen that LINK_PROTOCOL/STATE packets with a valid non-zero unicast acknowledge number may bypass BCAST_PROTOCOL initialization, NAME_DISTRIBUTOR and other STATE packets with invalid broadcast acknowledge numbers, leading to premature opening of the broadcast link. When the bypassed packets finally arrive, they are inadvertently accepted, and the already correctly initialized acknowledge number in the broadcast receive link is overwritten by the invalid (zero) value of the said packets. After this the broadcast link goes stale. We now fix this by marking the packets where we know the acknowledge value is or may be invalid, and then ignoring the acks from those. To this purpose, we claim an unused bit in the header to indicate that the value is invalid. We set the bit to 1 in the initial BCAST_PROTOCOL synchronization packet and all initial ("bulk") NAME_DISTRIBUTOR packets, plus those LINK_PROTOCOL packets sent out before the broadcast links are fully synchronized. This minor protocol update is fully backwards compatible. Reported-by: John Thompson Tested-by: John Thompson Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: transfer broadcast nacks in link state messages

2016-09-03T00:10:24Z

When we send broadcasts in clusters of more 70-80 nodes, we sometimes see the broadcast link resetting because of an excessive number of retransmissions. This is caused by a combination of two factors: 1) A 'NACK crunch", where loss of broadcast packets is discovered and NACK'ed by several nodes simultaneously, leading to multiple redundant broadcast retransmissions. 2) The fact that the NACKS as such also are sent as broadcast, leading to excessive load and packet loss on the transmitting switch/bridge. This commit deals with the latter problem, by moving sending of broadcast nacks from the dedicated BCAST_PROTOCOL/NACK message type to regular unicast LINK_PROTOCOL/STATE messages. We allocate 10 unused bits in word 8 of the said message for this purpose, and introduce a new capability bit, TIPC_BCAST_STATE_NACK in order to keep the change backwards compatible. Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add peer removal functionality

2016-08-19T06:36:07Z

Add TIPC_NL_PEER_REMOVE netlink command. This command can remove an offline peer node from the internal data structures. This will be supported by the tipc user space tool in iproute2. Signed-off-by: Richard Alpe Reviewed-by: Jon Maloy Acked-by: Ying Xue Signed-off-by: David S. Miller

tipc: dump monitor attributes

2016-07-26T21:26:42Z

In this commit, we dump the monitor attributes when queried. The link monitor attributes are separated into two kinds: 1. general attributes per bearer 2. specific attributes per node/peer This style resembles the socket attributes and the nametable publications per socket. Reviewed-by: Jon Maloy Signed-off-by: Parthasarathy Bhuvaragan Signed-off-by: David S. Miller

tipc: get monitor threshold for the cluster

2016-07-26T21:26:42Z

In this commit, we add support to fetch the configured cluster monitoring threshold. Reviewed-by: Jon Maloy Signed-off-by: Parthasarathy Bhuvaragan Signed-off-by: David S. Miller